Feeds:
Posts
Comments

Archive for the ‘PKC’ Category

Summary of Translational Medicine – e-Series A: Cardiovascular Diseases, Volume Four – Part 1

Summary of Translational Medicine – e-Series A: Cardiovascular Diseases, Volume Four – Part 1

Author and Curator: Larry H Bernstein, MD, FCAP

and

Curator: Aviva Lev-Ari, PhD, RN

Article ID #135: Summary of Translational Medicine – e-Series A: Cardiovascular Diseases, Volume Four – Part 1. Published on 4/28/2014

WordCloud Image Produced by Adam Tubman

 

Part 1 of Volume 4 in the e-series A: Cardiovascular Diseases and Translational Medicine, provides a foundation for grasping a rapidly developing surging scientific endeavor that is transcending laboratory hypothesis testing and providing guidelines to:

  • Target genomes and multiple nucleotide sequences involved in either coding or in regulation that might have an impact on complex diseases, not necessarily genetic in nature.
  • Target signaling pathways that are demonstrably maladjusted, activated or suppressed in many common and complex diseases, or in their progression.
  • Enable a reduction in failure due to toxicities in the later stages of clinical drug trials as a result of this science-based understanding.
  • Enable a reduction in complications from the improvement of machanical devices that have already had an impact on the practice of interventional procedures in cardiology, cardiac surgery, and radiological imaging, as well as improving laboratory diagnostics at the molecular level.
  • Enable the discovery of new drugs in the continuing emergence of drug resistance.
  • Enable the construction of critical pathways and better guidelines for patient management based on population outcomes data, that will be critically dependent on computational methods and large data-bases.

What has been presented can be essentially viewed in the following Table:

 

Summary Table for TM - Part 1

Summary Table for TM – Part 1

 

 

 

There are some developments that deserve additional development:

1. The importance of mitochondrial function in the activity state of the mitochondria in cellular work (combustion) is understood, and impairments of function are identified in diseases of muscle, cardiac contraction, nerve conduction, ion transport, water balance, and the cytoskeleton – beyond the disordered metabolism in cancer.  A more detailed explanation of the energetics that was elucidated based on the electron transport chain might also be in order.

2. The processes that are enabling a more full application of technology to a host of problems in the environment we live in and in disease modification is growing rapidly, and will change the face of medicine and its allied health sciences.

 

Electron Transport and Bioenergetics

Deferred for metabolomics topic

Synthetic Biology

Introduction to Synthetic Biology and Metabolic Engineering

Kristala L. J. Prather: Part-1    <iBiology > iBioSeminars > Biophysics & Chemical Biology >

http://www.ibiology.org Lecturers generously donate their time to prepare these lectures. The project is funded by NSF and NIGMS, and is supported by the ASCB and HHMI.
Dr. Prather explains that synthetic biology involves applying engineering principles to biological systems to build “biological machines”.

Dr. Prather has received numerous awards both for her innovative research and for excellence in teaching.  Learn more about how Kris became a scientist at
Prather 1: Synthetic Biology and Metabolic Engineering  2/6/14IntroductionLecture Overview In the first part of her lecture, Dr. Prather explains that synthetic biology involves applying engineering principles to biological systems to build “biological machines”. The key material in building these machines is synthetic DNA. Synthetic DNA can be added in different combinations to biological hosts, such as bacteria, turning them into chemical factories that can produce small molecules of choice. In Part 2, Prather describes how her lab used design principles to engineer E. coli that produce glucaric acid from glucose. Glucaric acid is not naturally produced in bacteria, so Prather and her colleagues “bioprospected” enzymes from other organisms and expressed them in E. coli to build the needed enzymatic pathway. Prather walks us through the many steps of optimizing the timing, localization and levels of enzyme expression to produce the greatest yield. Speaker Bio: Kristala Jones Prather received her S.B. degree from the Massachusetts Institute of Technology and her PhD at the University of California, Berkeley both in chemical engineering. Upon graduation, Prather joined the Merck Research Labs for 4 years before returning to academia. Prather is now an Associate Professor of Chemical Engineering at MIT and an investigator with the multi-university Synthetic Biology Engineering Reseach Center (SynBERC). Her lab designs and constructs novel synthetic pathways in microorganisms converting them into tiny factories for the production of small molecules. Dr. Prather has received numerous awards both for her innovative research and for excellence in teaching.

VIEW VIDEOS

https://www.youtube.com/watch?feature=player_embedded&v=ndThuqVumAk#t=0

https://www.youtube.com/watch?feature=player_embedded&v=ndThuqVumAk#t=12

https://www.youtube.com/watch?feature=player_embedded&v=ndThuqVumAk#t=74

https://www.youtube.com/watch?feature=player_embedded&v=ndThuqVumAk#t=129

https://www.youtube.com/watch?feature=player_embedded&v=ndThuqVumAk#t=168

https://www.youtube.com/watch?feature=player_embedded&v=ndThuqVumAk

 

II. Regulatory Effects of Mammalian microRNAs

Calcium Cycling in Synthetic and Contractile Phasic or Tonic Vascular Smooth Muscle Cells

in INTECH
Current Basic and Pathological Approaches to
the Function of Muscle Cells and Tissues – From Molecules to HumansLarissa Lipskaia, Isabelle Limon, Regis Bobe and Roger Hajjar
Additional information is available at the end of the chapter
http://dx.doi.org/10.5772/48240
1. Introduction
Calcium ions (Ca ) are present in low concentrations in the cytosol (~100 nM) and in high concentrations (in mM range) in both the extracellular medium and intracellular stores (mainly sarco/endo/plasmic reticulum, SR). This differential allows the calcium ion messenger that carries information
as diverse as contraction, metabolism, apoptosis, proliferation and/or hypertrophic growth. The mechanisms responsible for generating a Ca signal greatly differ from one cell type to another.
In the different types of vascular smooth muscle cells (VSMC), enormous variations do exist with regard to the mechanisms responsible for generating Ca signal. In each VSMC phenotype (synthetic/proliferating and contractile [1], tonic or phasic), the Ca signaling system is adapted to its particular function and is due to the specific patterns of expression and regulation of Ca.
For instance, in contractile VSMCs, the initiation of contractile events is driven by mem- brane depolarization; and the principal entry-point for extracellular Ca is the voltage-operated L-type calcium channel (LTCC). In contrast, in synthetic/proliferating VSMCs, the principal way-in for extracellular Ca is the store-operated calcium (SOC) channel.
Whatever the cell type, the calcium signal consists of  limited elevations of cytosolic free calcium ions in time and space. The calcium pump, sarco/endoplasmic reticulum Ca ATPase (SERCA), has a critical role in determining the frequency of SR Ca release by upload into the sarcoplasmic
sensitivity of  SR calcium channels, Ryanodin Receptor, RyR and Inositol tri-Phosphate Receptor, IP3R.
Synthetic VSMCs have a fibroblast appearance, proliferate readily, and synthesize increased levels of various extracellular matrix components, particularly fibronectin, collagen types I and III, and tropoelastin [1].
Contractile VSMCs have a muscle-like or spindle-shaped appearance and well-developed contractile apparatus resulting from the expression and intracellular accumulation of thick and thin muscle filaments [1].
Schematic representation of Calcium Cycling in Contractile and Proliferating VSMCs

Schematic representation of Calcium Cycling in Contractile and Proliferating VSMCs

 

Figure 1. Schematic representation of Calcium Cycling in Contractile and Proliferating VSMCs.

Left panel: schematic representation of calcium cycling in quiescent /contractile VSMCs. Contractile re-sponse is initiated by extracellular Ca influx due to activation of Receptor Operated Ca (through phosphoinositol-coupled receptor) or to activation of L-Type Calcium channels (through an increase in luminal pressure). Small increase of cytosolic due IP3 binding to IP3R (puff) or RyR activation by LTCC or ROC-dependent Ca influx leads to large SR Ca IP3R or RyR clusters (“Ca -induced Ca SR calcium pumps (both SERCA2a and SERCA2b are expressed in quiescent VSMCs), maintaining high concentration of cytosolic Ca and setting the sensitivity of RyR or IP3R for the next spike.
Contraction of VSMCs occurs during oscillatory Ca transient.
Middle panel: schematic representa tion of atherosclerotic vessel wall. Contractile VSMC are located in the media layer, synthetic VSMC are located in sub-endothelial intima.
Right panel: schematic representation of calcium cycling in quiescent /contractile VSMCs. Agonist binding to phosphoinositol-coupled receptor leads to the activation of IP3R resulting in large increase in cytosolic Ca calcium pumps (only SERCA2b, having low turnover and low affinity to Ca depletion leads to translocation of SR Ca sensor STIM1 towards PM, resulting in extracellular Ca influx though opening of Store Operated Channel (CRAC). Resulted steady state Ca transient is critical for activation of proliferation-related transcription factors ‘NFAT).
Abbreviations: PLC – phospholipase C; PM – plasma membrane; PP2B – Ca /calmodulin-activated protein phosphatase 2B (calcineurin); ROC- receptor activated channel; IP3 – inositol-1,4,5-trisphosphate, IP3R – inositol-1,4,5- trisphosphate receptor; RyR – ryanodine receptor; NFAT – nuclear factor of activated T-lymphocytes; VSMC – vascular smooth muscle cells; SERCA – sarco(endo)plasmic reticulum Ca sarcoplasmic reticulum.

 

Time for New DNA Synthesis and Sequencing Cost Curves

By Rob Carlson

I’ll start with the productivity plot, as this one isn’t new. For a discussion of the substantial performance increase in sequencing compared to Moore’s Law, as well as the difficulty of finding this data, please see this post. If nothing else, keep two features of the plot in mind: 1) the consistency of the pace of Moore’s Law and 2) the inconsistency and pace of sequencing productivity. Illumina appears to be the primary driver, and beneficiary, of improvements in productivity at the moment, especially if you are looking at share prices. It looks like the recently announced NextSeq and Hiseq instruments will provide substantially higher productivities (hand waving, I would say the next datum will come in another order of magnitude higher), but I think I need a bit more data before officially putting another point on the plot.

 

cost-of-oligo-and-gene-synthesis

cost-of-oligo-and-gene-synthesis

Illumina’s instruments are now responsible for such a high percentage of sequencing output that the company is effectively setting prices for the entire industry. Illumina is being pushed by competition to increase performance, but this does not necessarily translate into lower prices. It doesn’t behoove Illumina to drop prices at this point, and we won’t see any substantial decrease until a serious competitor shows up and starts threatening Illumina’s market share. The absence of real competition is the primary reason sequencing prices have flattened out over the last couple of data points.

Note that the oligo prices above are for column-based synthesis, and that oligos synthesized on arrays are much less expensive. However, array synthesis comes with the usual caveat that the quality is generally lower, unless you are getting your DNA from Agilent, which probably means you are getting your dsDNA from Gen9.

Note also that the distinction between the price of oligos and the price of double-stranded sDNA is becoming less useful. Whether you are ordering from Life/Thermo or from your local academic facility, the cost of producing oligos is now, in most cases, independent of their length. That’s because the cost of capital (including rent, insurance, labor, etc) is now more significant than the cost of goods. Consequently, the price reflects the cost of capital rather than the cost of goods. Moreover, the cost of the columns, reagents, and shipping tubes is certainly more than the cost of the atoms in the sDNA you are ostensibly paying for. Once you get into longer oligos (substantially larger than 50-mers) this relationship breaks down and the sDNA is more expensive. But, at this point in time, most people aren’t going to use longer oligos to assemble genes unless they have a tricky job that doesn’t work using short oligos.

Looking forward, I suspect oligos aren’t going to get much cheaper unless someone sorts out how to either 1) replace the requisite human labor and thereby reduce the cost of capital, or 2) finally replace the phosphoramidite chemistry that the industry relies upon.

IDT’s gBlocks come at prices that are constant across quite substantial ranges in length. Moreover, part of the decrease in price for these products is embedded in the fact that you are buying smaller chunks of DNA that you then must assemble and integrate into your organism of choice.

Someone who has purchased and assembled an absolutely enormous amount of sDNA over the last decade, suggested that if prices fell by another order of magnitude, he could switch completely to outsourced assembly. This is a potentially interesting “tipping point”. However, what this person really needs is sDNA integrated in a particular way into a particular genome operating in a particular host. The integration and testing of the new genome in the host organism is where most of the cost is. Given the wide variety of emerging applications, and the growing array of hosts/chassis, it isn’t clear that any given technology or firm will be able to provide arbitrary synthetic sequences incorporated into arbitrary hosts.

 TrackBack URL: http://www.synthesis.cc/cgi-bin/mt/mt-t.cgi/397

 

Startup to Strengthen Synthetic Biology and Regenerative Medicine Industries with Cutting Edge Cell Products

28 Nov 2013 | PR Web

Dr. Jon Rowley and Dr. Uplaksh Kumar, Co-Founders of RoosterBio, Inc., a newly formed biotech startup located in Frederick, are paving the way for even more innovation in the rapidly growing fields of Synthetic Biology and Regenerative Medicine. Synthetic Biology combines engineering principles with basic science to build biological products, including regenerative medicines and cellular therapies. Regenerative medicine is a broad definition for innovative medical therapies that will enable the body to repair, replace, restore and regenerate damaged or diseased cells, tissues and organs. Regenerative therapies that are in clinical trials today may enable repair of damaged heart muscle following heart attack, replacement of skin for burn victims, restoration of movement after spinal cord injury, regeneration of pancreatic tissue for insulin production in diabetics and provide new treatments for Parkinson’s and Alzheimer’s diseases, to name just a few applications.

While the potential of the field is promising, the pace of development has been slow. One main reason for this is that the living cells required for these therapies are cost-prohibitive and not supplied at volumes that support many research and product development efforts. RoosterBio will manufacture large quantities of standardized primary cells at high quality and low cost, which will quicken the pace of scientific discovery and translation to the clinic. “Our goal is to accelerate the development of products that incorporate living cells by providing abundant, affordable and high quality materials to researchers that are developing and commercializing these regenerative technologies” says Dr. Rowley

 

Life at the Speed of Light

http://kcpw.org/?powerpress_pinw=92027-podcast

NHMU Lecture featuring – J. Craig Venter, Ph.D.
Founder, Chairman, and CEO – J. Craig Venter Institute; Co-Founder and CEO, Synthetic Genomics Inc.

J. Craig Venter, Ph.D., is Founder, Chairman, and CEO of the J. Craig Venter Institute (JVCI), a not-for-profit, research organization dedicated to human, microbial, plant, synthetic and environmental research. He is also Co-Founder and CEO of Synthetic Genomics Inc. (SGI), a privately-held company dedicated to commercializing genomic-driven solutions to address global needs.

In 1998, Dr. Venter founded Celera Genomics to sequence the human genome using new tools and techniques he and his team developed.  This research culminated with the February 2001 publication of the human genome in the journal, Science. Dr. Venter and his team at JVCI continue to blaze new trails in genomics.  They have sequenced and a created a bacterial cell constructed with synthetic DNA,  putting humankind at the threshold of a new phase of biological research.  Whereas, we could  previously read the genetic code (sequencing genomes), we can now write the genetic code for designing new species.

The science of synthetic genomics will have a profound impact on society, including new methods for chemical and energy production, human health and medical advances, clean water, and new food and nutritional products. One of the most prolific scientists of the 21st century for his numerous pioneering advances in genomics,  he  guides us through this emerging field, detailing its origins, current challenges, and the potential positive advances.

His work on synthetic biology truly embodies the theme of “pushing the boundaries of life.”  Essentially, Venter is seeking to “write the software of life” to create microbes designed by humans rather than only through evolution. The potential benefits and risks of this new technology are enormous. It also requires us to examine, both scientifically and philosophically, the question of “What is life?”

J Craig Venter wants to digitize DNA and transmit the signal to teleport organisms

http://pharmaceuticalintelligence.com/2013/11/01/j-craig-venter-wants-to-digitize-dna-and-transmit-the-signal-to-teleport-organisms/

2013 Genomics: The Era Beyond the Sequencing of the Human Genome: Francis Collins, Craig Venter, Eric Lander, et al.

http://pharmaceuticalintelligence.com/2013/02/11/2013-genomics-the-era-beyond-the-sequencing-human-genome-francis-collins-craig-venter-eric-lander-et-al/

Human Longevity Inc (HLI) – $70M in Financing of Venter’s New Integrative Omics and Clinical Bioinformatics

http://pharmaceuticalintelligence.com/2014/03/05/human-longevity-inc-hli-70m-in-financing-of-venters-new-integrative-omics-and-clinical-bioinformatics/

 

 

Where Will the Century of Biology Lead Us?

By Randall Mayes

A technology trend analyst offers an overview of synthetic biology, its potential applications, obstacles to its development, and prospects for public approval.

  • In addition to boosting the economy, synthetic biology projects currently in development could have profound implications for the future of manufacturing, sustainability, and medicine.
  • Before society can fully reap the benefits of synthetic biology, however, the field requires development and faces a series of hurdles in the process. Do researchers have the scientific know-how and technical capabilities to develop the field?

Biology + Engineering = Synthetic Biology

Bioengineers aim to build synthetic biological systems using compatible standardized parts that behave predictably. Bioengineers synthesize DNA parts—oligonucleotides composed of 50–100 base pairs—which make specialized components that ultimately make a biological system. As biology becomes a true engineering discipline, bioengineers will create genomes using mass-produced modular units similar to the microelectronics and computer industries.

Currently, bioengineering projects cost millions of dollars and take years to develop products. For synthetic biology to become a Schumpeterian revolution, smaller companies will need to be able to afford to use bioengineering concepts for industrial applications. This will require standardized and automated processes.

A major challenge to developing synthetic biology is the complexity of biological systems. When bioengineers assemble synthetic parts, they must prevent cross talk between signals in other biological pathways. Until researchers better understand these undesired interactions that nature has already worked out, applications such as gene therapy will have unwanted side effects. Scientists do not fully understand the effects of environmental and developmental interaction on gene expression. Currently, bioengineers must repeatedly use trial and error to create predictable systems.

Similar to physics, synthetic biology requires the ability to model systems and quantify relationships between variables in biological systems at the molecular level.

The second major challenge to ensuring the success of synthetic biology is the development of enabling technologies. With genomes having billions of nucleotides, this requires fast, powerful, and cost-efficient computers. Moore’s law, named for Intel co-founder Gordon Moore, posits that computing power progresses at a predictable rate and that the number of components in integrated circuits doubles each year until its limits are reached. Since Moore’s prediction, computer power has increased at an exponential rate while pricing has declined.

DNA sequencers and synthesizers are necessary to identify genes and make synthetic DNA sequences. Bioengineer Robert Carlson calculated that the capabilities of DNA sequencers and synthesizers have followed a pattern similar to computing. This pattern, referred to as the Carlson Curve, projects that scientists are approaching the ability to sequence a human genome for $1,000, perhaps in 2020. Carlson calculated that the costs of reading and writing new genes and genomes are falling by a factor of two every 18–24 months. (see recent Carlson comment on requirement to read and write for a variety of limiting  conditions).

Startup to Strengthen Synthetic Biology and Regenerative Medicine Industries with Cutting Edge Cell Products

http://pharmaceuticalintelligence.com/2013/11/28/startup-to-strengthen-synthetic-biology-and-regenerative-medicine-industries-with-cutting-edge-cell-products/

Synthetic Biology: On Advanced Genome Interpretation for Gene Variants and Pathways: What is the Genetic Base of Atherosclerosis and Loss of Arterial Elasticity with Aging

http://pharmaceuticalintelligence.com/2013/05/17/synthetic-biology-on-advanced-genome-interpretation-for-gene-variants-and-pathways-what-is-the-genetic-base-of-atherosclerosis-and-loss-of-arterial-elasticity-with-aging/

Synthesizing Synthetic Biology: PLOS Collections

http://pharmaceuticalintelligence.com/2012/08/17/synthesizing-synthetic-biology-plos-collections/

Capturing ten-color ultrasharp images of synthetic DNA structures resembling numerals 0 to 9

http://pharmaceuticalintelligence.com/2014/02/05/capturing-ten-color-ultrasharp-images-of-synthetic-dna-structures-resembling-numerals-0-to-9/

Silencing Cancers with Synthetic siRNAs

http://pharmaceuticalintelligence.com/2013/12/09/silencing-cancers-with-synthetic-sirnas/

Genomics Now—and Beyond the Bubble

Futurists have touted the twenty-first century as the century of biology based primarily on the promise of genomics. Medical researchers aim to use variations within genes as biomarkers for diseases, personalized treatments, and drug responses. Currently, we are experiencing a genomics bubble, but with advances in understanding biological complexity and the development of enabling technologies, synthetic biology is reviving optimism in many fields, particularly medicine.

BY MICHAEL BROOKS    17 APR, 2014     http://www.newstatesman.com/

Michael Brooks holds a PhD in quantum physics. He writes a weekly science column for the New Statesman, and his most recent book is The Secret Anarchy of Science.

The basic idea is that we take an organism – a bacterium, say – and re-engineer its genome so that it does something different. You might, for instance, make it ingest carbon dioxide from the atmosphere, process it and excrete crude oil.

That project is still under construction, but others, such as using synthesised DNA for data storage, have already been achieved. As evolution has proved, DNA is an extraordinarily stable medium that can preserve information for millions of years. In 2012, the Harvard geneticist George Church proved its potential by taking a book he had written, encoding it in a synthesised strand of DNA, and then making DNA sequencing machines read it back to him.

When we first started achieving such things it was costly and time-consuming and demanded extraordinary resources, such as those available to the millionaire biologist Craig Venter. Venter’s team spent most of the past two decades and tens of millions of dollars creating the first artificial organism, nicknamed “Synthia”. Using computer programs and robots that process the necessary chemicals, the team rebuilt the genome of the bacterium Mycoplasma mycoides from scratch. They also inserted a few watermarks and puzzles into the DNA sequence, partly as an identifying measure for safety’s sake, but mostly as a publicity stunt.

What they didn’t do was redesign the genome to do anything interesting. When the synthetic genome was inserted into an eviscerated bacterial cell, the new organism behaved exactly the same as its natural counterpart. Nevertheless, that Synthia, as Venter put it at the press conference to announce the research in 2010, was “the first self-replicating species we’ve had on the planet whose parent is a computer” made it a standout achievement.

Today, however, we have entered another era in synthetic biology and Venter faces stiff competition. The Steve Jobs to Venter’s Bill Gates is Jef Boeke, who researches yeast genetics at New York University.

Boeke wanted to redesign the yeast genome so that he could strip out various parts to see what they did. Because it took a private company a year to complete just a small part of the task, at a cost of $50,000, he realised he should go open-source. By teaching an undergraduate course on how to build a genome and teaming up with institutions all over the world, he has assembled a skilled workforce that, tinkering together, has made a synthetic chromosome for baker’s yeast.

 

Stepping into DIYbio and Synthetic Biology at ScienceHack

Posted April 22, 2014 by Heather McGaw and Kyrie Vala-Webb

We got a crash course on genetics and protein pathways, and then set out to design and build our own pathways using both the “Genomikon: Violacein Factory” kit and Synbiota platform. With Synbiota’s software, we dragged and dropped the enzymes to create the sequence that we were then going to build out. After a process of sketching ideas, mocking up pathways, and writing hypotheses, we were ready to start building!

The night stretched long, and at midnight we were forced to vacate the school. Not quite finished, we loaded our delicate bacteria, incubator, and boxes of gloves onto the bus and headed back to complete our bacterial transformation in one of our hotel rooms. Jammed in between the beds and the mini-fridge, we heat-shocked our bacteria in the hotel ice bucket. It was a surreal moment.

While waiting for our bacteria, we held an “unconference” where we explored bioethics, security and risk related to synthetic biology, 3D printing on Mars, patterns in juggling (with live demonstration!), and even did a Google Hangout with Rob Carlson. Every few hours, we would excitedly check in on our bacteria, looking for bacterial colonies and the purple hue characteristic of violacein.

Most impressive was the wildly successful and seamless integration of a diverse set of people: in a matter of hours, we were transformed from individual experts and practitioners in assorted fields into cohesive and passionate teams of DIY biologists and science hackers. The ability of everyone to connect and learn was a powerful experience, and over the course of just one weekend we were able to challenge each other and grow.

Returning to work on Monday, we were hungry for more. We wanted to find a way to bring the excitement and energy from the weekend into the studio and into the projects we’re working on. It struck us that there are strong parallels between design and DIYbio, and we knew there was an opportunity to bring some of the scientific approaches and curiosity into our studio.

 

 

Read Full Post »

Curation, HealthCare System in the US, and Calcium Signaling Effects on Cardiac Contraction, Heart Failure, and Atrial Fibrillation, and the Relationship of Calcium Release at the Myoneural Junction to Beta Adrenergic Release

Curation, HealthCare System in the US, and Calcium Signaling Effects on Cardiac Contraction, Heart Failure, and Atrial Fibrillation, and the Relationship of Calcium Release at the Myoneural Junction to Beta Adrenergic Release

Curator and e-book Contributor: Larry H. Bernstein, MD, FCAP
Curator and BioMedicine e-Series Editor-in-Chief: Aviva Lev Ari, PhD, RN

and 

Content Consultant to Six-Volume e-SERIES A: Cardiovascular Diseases: Justin Pearlman, MD, PhD, FACC

This portion summarises what we have covered and is now familiar to the reader.  There are three related topics, and an extension of this embraces other volumes and chapters before and after this reading.  This approach to the document has advantages over the multiple authored textbooks that are and have been pervasive as a result of the traditional publication technology.  It has been stated by the founder of ScoopIt, that amount of time involved is considerably less than required for the original publications used, but the organization and construction is a separate creative process.  In these curations we amassed on average five articles in one curation, to which, two or three curators contributed their views.  There were surprises, and there were unfulfilled answers along the way.  The greatest problem that is being envisioned is the building a vision that bridges and unmasks the hidden “dark matter” between the now declared “OMICS”, to get a more real perspective on what is conjecture and what is actionable.  This is in some respects unavoidable because the genome is an alphabet that is matched to the mino acid sequences of proteins, which themselves are three dimensional drivers of sequences of metabolic reactions that can be altered by the accumulation of substrates in critical placements, and in addition, the proteome has functional proteins whose activity is a regulatory function and not easily identified.  In the end, we have to have a practical conception, recognizing the breadth of evolutionary change, and make sense of what we have, while searching for more.

We introduced the content as follows:

1. We introduce the concept of curation in the digital context, and it’s application to medicine and related scientific discovery.

Topics were chosen were used to illustrate this process in the form of a pattern, which is mostly curation, but is significantly creative, as it emerges in the context of this e-book.

  • Alternative solutions in Treatment of Heart Failure (HF), medical devices, biomarkers and agent efficacy is handled all in one chapter.
  • PCI for valves vs Open heart Valve replacement
  • PDA and Complications of Surgery — only curation could create the picture of this unique combination of debate, as exemplified of Endarterectomy (CEA) vs Stenting the Carotid Artery (CAS), ischemic leg, renal artery stenosis.

2. The etiology, or causes, of cardiovascular diseases consist of mechanistic explanations for dysfunction relating to the heart or vascular system. Every one of a long list of abnormalities has a path that explains the deviation from normal. With the completion of the analysis of the human genome, in principle all of the genetic basis for function and dysfunction are delineated. While all genes are identified, and the genes code for all the gene products that constitute body functions, there remains more unknown than known.

3. Human genome, and in combination with improved imaging methods, genomics offers great promise in changing the course of disease and aging.

4. If we tie together Part 1 and Part 2, there is ample room for considering clinical outcomes based on individual and organizational factors for best performance. This can really only be realized with considerable improvement in information infrastructure, which has miles to go.

Curation

Curation is an active filtering of the web’s  and peer reviewed literature found by such means – immense amount of relevant and irrelevant content. As a result content may be disruptive. However, in doing good curation, one does more than simply assign value by presentation of creative work in any category. Great curators comment and share experience across content, authors and themes.
Great curators may see patterns others don’t, or may challenge or debate complex and apparently conflicting points of view.  Answers to specifically focused questions comes from the hard work of many in laboratory settings creatively establishing answers to definitive questions, each a part of the larger knowledge-base of reference. There are those rare “Einstein’s” who imagine a whole universe, unlike the three blindmen of the Sufi tale.  One held the tail, the other the trunk, the other the ear, and they all said this is an elephant!
In my reading, I learn that the optimal ratio of curation to creation may be as high as 90% curation to 10% creation. Creating content is expensive. Curation, by comparison, is much less expensive.  The same source says “Scoop.it is my content marketing testing “sandbox”. In sharing, he says that comments provide the framework for what and how content is shared.

Healthcare and Affordable Care Act

We enter year 2014 with the Affordable Care Act off to a slow start because of the implementation of the internet signup requiring a major repair, which is, unfortunately, as expected for such as complex job across the US, and with many states unwilling to participate.  But several states – California, Connecticut, and Kentucky – had very effective state designed signups, separate from the federal system.  There has been a very large rush and an extension to sign up. There are many features that we can take note of:

1. The healthcare system needed changes because we have the most costly system, are endowed with advanced technology, and we have inexcusable outcomes in several domains of care, including, infant mortality, and prenatal care – but not in cardiology.

2. These changes that are notable are:

  • The disparities in outcome are magnified by a large disparity in highest to lowest income bracket.
  • This is also reflected in educational status, and which plays out in childhood school lunches, and is also affected by larger class size and cutbacks in school programs.
  • This is not  helped by a large paralysis in the two party political system and the three legs of government unable to deal with work and distraction.
  • Unemployment is high, and the banking and home construction, home buying, and rental are in realignment, but interest rates are problematic.

3.  The  medical care system is affected by the issues above, but the complexity is not to be discounted.

  •  The medical schools are unable at this time to provide the influx of new physicians needed, so we depend on a major influx of physicians from other countries
  • The technology for laboratories, proteomic and genomic as well as applied medical research is rejuvenating the practice in cardiology more rapidly than any other field.
  • In fields that are imaging related the life cycle of instruments is shorter than the actual lifetime use of the instruments, which introduces a shortening of ROI.
  • Hospitals are consolidating into large consortia in order to maintain a more viable system for referral of specialty cases, and also is centralizing all terms of business related to billing.
  • There is reduction in independent physician practices that are being incorporated into the hospital enterprise with Part B billing under the Physician Organization – as in Partners in Greater Boston, with the exception of “concierge” medical practices.
  • There is consolidation of specialty laboratory services within state, with only the most specialized testing going out of state (Quest, LabCorp, etc.)
  • Medicaid is expanded substantially under the new ACA.
  • The federal government as provider of services is reducing the number of contractors for – medical devices, diabetes self-testing, etc.
  • The current rearrangements seeks to provide a balance between capital expenses and fixed labor costs that it can control, reduce variable costs (reagents, pharmaceutical), and to take in more patients with less delay and better performance – defined by outside agencies.

Cardiology, Genomics, and calcium ion signaling and ion-channels in cardiomyocyte function in health and disease – including heart failure, rhythm abnormalities, and the myoneural release of neurotransmitter at the vesicle junction.

This portion is outlined as follows:

2.1 Human Genome: Congenital Etiological Sources of Cardiovascular Disease

2.2 The Role of Calcium in Health and Disease

2.3 Vasculature and Myocardium: Diagnosing the Conditions of Disease

Genomics & Genetics of Cardiovascular Disease Diagnoses

actin cytoskeleton

wall stress, ventricular workload, contractile reserve

Genetic Base of Atherosclerosis and Loss of Arterial Elasticity with Aging

calcium and actin skeleton, signaling, cell motility

hypertension & vascular compliance

Genetics of Conduction Disease

Ca+ stimulated exostosis: calmodulin & PKC (neurotransmitter)

complications & MVR

disruption of Ca2+ homeostasis cardiac & vascular smooth muscle

synaptotagmin as Ca2+ sensor & vesicles

atherosclerosis & ion channels


It is increasingly clear that there are mutations that underlie many human diseases, and this is true of the cardiovascular system.  The mutations are mistakes in the insertion of a purine nucleotide, which may or may not have any consequence.  This is why the associations that are being discovered in research require careful validation, and even require demonstration in “models” before pursuing the design of pharmacological “target therapy”.  The genomics in cardiovascular disease involves very serious congenital disorders that are asserted early in life, but the effects of and development of atherosclerosis involving large and medium size arteries has a slow progression and is not dominated by genomic expression.  This is characterized by loss of arterial elasticity. In addition there is the development of heart failure, which involves the cardiomyocyte specifically.  The emergence of regenerative medical interventions, based on pleuripotent inducible stem cell therapy is developing rapidly as an intervention in this sector.

Finally, it is incumbent on me to call attention to the huge contribution that research on calcium (Ca2+) signaling has made toward the understanding of cardiac contraction and to the maintenance of the heart rhythm.  The heart is a syncytium, different than skeletal and smooth muscle, and the innervation is by the vagus nerve, which has terminal endings at vesicles which discharge at the myocyte junction.  The heart specifically has calmodulin kinase CaMK II, and it has been established that calmodulin is involved in the calcium spark that triggers contraction.  That is only part of the story.  Ion transport occurs into or out of the cell, the latter termed exostosis.  Exostosis involves CaMK II and pyruvate kinase (PKC), and they have independent roles.  This also involves K+-Na+-ATPase.  The cytoskeleton is also discussed, but the role of aquaporin in water transport appears elsewhere, as the transport of water between cells.  When we consider the Gibbs-Donnan equilibrium, which precedes the current work by a century, we recall that there is an essential balance between extracellular Na+ + Ca2+ and the intracellular K+ + Mg2+, and this has been superceded by an incompletely defined relationship between ions that are cytoplasmic and those that are mitochondrial.  The glass is half full!

 

Read Full Post »

Ca2+-Stimulated Exocytosis:  The Role of Calmodulin and Protein Kinase C in Ca2+ Regulation of Hormone and Neurotransmitter

Article XIII Ca2+-Stimulated Exocytosis The Role of Calmodulin and Protein Kinase C in Ca2+ Regulation of Hormone and Neurotransmitter

Writer and Curator: Larry H Bernstein, MD, FCAP
and
Curator and Content Editor: Aviva Lev-Ari, PhD, RN

This article is Part V in a series of TWELVE articles, listed at the end of this article,  on the

  1. cytoskeleton,
  2. calcium calmodulin kinase signaling,
  3. muscle and nerve transduction, and
  4. calcium,
  5. Na+-K+-ATPase,
  6. neurohumoral activity and vesicles vital and essential for all functions related to
  • cell movement,
  • migration, and
  • contraction.

Calmodulin and Protein Kinase C Increase Ca–stimulated Secretion by Modulating
Membrane-attached Exocytic Machinery

YA Chen, V Duvvuri, H Schulmani, and RH.Scheller‡
From the ‡Howard Hughes Medical Institute, Department of Molecular and Cellular Physiology,
and the Department of Neurobiology, Stanford University School of Medicine, Stanford, CA

The molecular mechanisms underlying the Ca2+ regulation of hormone and neurotransmitter release
are largely unknown.

Using a reconstituted [3H]norepinephrine release assay in permeabilized PC12 cells, we found

  • essential proteins that support the triggering stage of Ca2+-stimulated exocytosis
  • are enriched in an EGTA extract of brain membranes.
Fractionation of this extract allowed purification of two factors that stimulate secretion
  • in the absence of any other cytosolic proteins.
These are calmodulin and protein kinase Ca (PKCa). Their effects on secretion were
  • confirmed using commercial and recombinant proteins.
Calmodulin enhances secretion

  • in the absence of ATP, whereas
  • PKC requires ATP to increase secretion, suggesting that
  • phosphorylation is involved in PKC-mediated stimulation
  • but not calmodulin mediated stimulation.
  • Both proteins modulate
    • The half-maximal increase was elicited by
      3 nM PKC and 75 nM calmodulin.
These results suggest that calmodulin and PKC increase Ca2+-activated exocytosis by
  • directly modulating the membrane- or cytoskeleton-attached exocytic machinery
    downstream of Ca2+ elevation.

The abbreviations used are:

NE, norepinephrine; PKC, protein kinase C; CaM, calmodulin; SNAP-25, synaptosome-associated protein of 25 kDa; CAPS, calcium-dependent activator protein for secretion; SNARE, SNAP (soluble N-ethylmaleimide-sensitive factor attachment proteins) receptor; CaMK, Ca2+/calmodulin-dependent protein kinase; PAGE, polyacrylamide gel electrophoresis; AMP-PNP, adenosine 59-(b,g- imido) triphosphate;  HA, hydroxyapatite

*This work was supported in part by Conte Center Grant MH48108. The costs of publication of
this article were defrayed in part by the payment of page charges. This article has been marked
“advertisement” in accordance with 18 U.S.C. Section 1734.

The molecular mechanisms of presynaptic vesicle release have been extensively examined
by a combination of

  • biochemical,
  • genetic, and
  • electrophysiological techniques.

A series of protein-protein interaction cascades have been proposed to lead to vesicle
docking and fusion
(1–3). The SNARE protein family, including

  • syntaxin, SNAP-25, and vesicle-associated membrane protein
    (VAMP, also called synaptobrevin),
  • plays an essential role in promoting membrane fusion, and
  • is thought to comprise the basic fusion machinery (4, 5).

In Ca2+-stimulated exocytosis, many additional proteins are important in the Ca2+ regulation
of the basic membrane trafficking apparatus.
Calcium

  • not only triggers rapid fusion of release-competent vesicles, but is also involved in
  • earlier processes which replenish the pool of readily releasable vesicles (6).

Furthermore, it appears to be critical in initiating several forms of synaptic plasticity including

  • post-tetanic potentiation (7).

The molecular mechanisms by which Ca2+ regulates these processes is not well understood.


PC12 cells have often been utilized to study Ca2+-activated exocytosis
, as

  • they offer a homogeneous cell population that possesses the same basic exocytic machinery as neurons (8).

In this study, we used an established cracked cell assay, in which

  • [3H]norepinephrine (NE)1 labeled PC12 cells are
  • permeabilized by mechanical “cracking” and
  • then reconstituted for secretion of NE in the presence of test proteins (9).

Transmitter-filled vesicles and intracellular cytoskeletal structures

  • remain intact in these cells,
  • while cytosolic proteins leak out (10).

These cracked cells readily release NE upon addition of

  • ATP,
  • brain cytosol, and
  • 1 mM free Ca2+
    • at an elevated temperature.

We term this a “composite assay,” as

  • all essential components are added into one reaction mixture.

Alternatively, cracked cells can be

  • first primed with cytosol and ATP, washed, then
  • reconstituted for NE release with cytosol and Ca2+ (11).

This sequential priming-triggering protocol is useful

  • for determining whether a protein acts early or late in the exocytic pathway, and
  • whether its effect is dependent on Ca2+ or ATP.

This semi-intact cell system serves as

  • a bridge between an in vitro system comprised of purified components, and
  • electro-physiological systems that monitor release in vivo.
  • It provides information on protein functions in a cell with an intact membrane infrastructure while being easily manipulatable.

Ca2+ regulation by membrane depolarization is no longer a concern, as
intra-cellular Ca2+ concentration can be controlled by a buffered solution.

  • Indirect readout of neurotransmitter release using a postsynaptic cell is replaced by
  • direct readout of [3H]NE released into the buffer.

Complications associated with interpreting overlapping

  • exo- and endocytotic signals are also eliminated as only one round of exocytosis is measured.

Finally, concentration estimates are likely to be accurate, since

  • added compounds do not need to diffuse long distances along axons and dendrites to their sites of action.

Using this assay, several proteins required for NE release have been purified from rat brain cytosol, including

  • phosphatidyl-inositol transfer protein (12),
  • phosphatidylinositol-4-phosphate 5-kinase (13), and
  • calcium-dependent activator protein for secretion (CAPS) (9).

The validity of the cracked cell system is confirmed by the finding that

  • phosphatidylinositol transfer protein and CAPS are mammalian homologues of
    • yeast SEC14p (12) and
    • nematode UNC31p, respectively (14),
  • both proteins involved in membrane trafficking (15, 16).

Calmodulin is the most ubiquitous calcium mediator in eukaryotic cells, yet its involvement in membrane trafficking has not been well established. Some early studies showed

  • that calmodulin inhibitors (17–19), anti-calmodulin antibodies (20,21),

or

  • calmodulin binding inhibitory peptides (22) inhibited Ca2+-activated exocytosis.

However, in other studies, calmodulin-binding peptides and an anti-calmodulin antibody led to the conclusion that

  • calmodulin is only involved in endocytosis,
  • not exocytosis (23).

More recently, it was reported that

  1. Ca2+/ calmodulin signals the completion of docking and
  2. triggers a late step of homotypic vacuole fusion in yeast,
  • thus suggesting an essential role for Ca2+/calmodulin in constitutive intracellular membrane fusion (24).

If calmodulin indeed plays an important role in exocytosis,

  • a likely target of calmodulin is
  • Ca2+/calmodulin-dependent protein kinase II (CaMKII),
    • a multifunctional kinase that is found on synaptic vesicles (25) and
    • has been shown to potentiate neurotransmitter release (26, 27).

Another Ca2+ signaling molecule, PKC, has also been implicated in regulated exocytosis.
In various cell systems, it has been shown that

  • the phorbol esters stimulate secretion (28, 29).

It is usually assumed that phorbol esters effect on exocytosis is

  • through activation of PKC,
  • but Munc13-1 was recently shown to be a presynaptic phorbol ester receptor that enhances neurotransmitter release (30, 31),

which complicates the interpretation of some earlier reports. The mode of action of PKC remains controversial. There is evidence

  • that PKC increases the intracellular Ca2+ levels by modulating plasma membrane Ca2+ channels (32, 33),
  • that it increases the size of the release competent vesicle pool (34, 35), or
  • that it increases the Ca2+ sensitivity of the membrane trafficking apparatus (36).

no consensus on these issues has been reached.

PKC substrates that have been implicated in exocytosis include

  1. SNAP-25 (37),
  2. synaptotagmin (28),
  3. CAPS (38), and
  4. nsec1 (39).

It is believed that upon phosphorylation, these PKC substrates might

  • interact differently with their binding partners, which, in turn,
  • leads to the enhancement of exocytosis.

In addition, evidence is accumulating that PKC and calmodulin interfere with each others actions, as

  • PKC phosphorylation sites are embedded in the calmodulin-binding domains of substrates such as
  • neuromodulin and
  • neurogranin (40).

It is therefore possible that PKC could modulate exocytosis via

  • a calmodulin-dependent pathway by synchronously releasing calmodulin from storage proteins.

In this study, we fractionated an EGTA extract of brain membranes in order to identify active components that could reconstitute release in the cracked cell assay system. We identified calmodulin and PKC as two active factors. Thus, we demonstrate that

  • calmodulin and PKC play a role in the Ca2+ regulation of exocytosis, and provide further insight into the mechanisms of their action.

DISCUSSION

 In this study, we first identified an EGTA extract of brain membranes as a protein source
  •  capable of reconstituting Ca2+- activated exocytosis in cracked PC12 cells.
EGTA only extracts a small pool of Ca2+-dependent membrane-associating proteins,
  • it served as an efficient initial purification step.
Further protein chromatography led to the identification of two active factors in the starting extract,
  • calmodulin and PKC,
  • which together accounted for about half of the starting activity.
Upon confirmation with commercially obtained proteins, this result unambiguously demonstrated
  • that calmodulin and PKC mediate aspects of Ca2+-dependent processes in exocytosis.
The finding that brain membrane EGTA extract alone is able
  • to replace cytosol in supporting Ca2+-triggered NE secretion
 in PC12 cells is somewhat surprising. We suggest that the likely explanation is 2-fold.
  1. some cytosolic proteins essential for exocytosis have a membrane-bound pool
    within permeabilized cells, whose activity might be sufficient for a normal level of exocytosis.
  2. although the 100,000 3 g membrane pellet was washed to remove as many cytosolic proteins as possible,
  • some cytosolic proteins that associate with membranes in a
    • Ca2+-independent manner are probably present in the membrane EGTA extract.
  • these proteins likely constitute only a small percentage of the proteins in the extract, as
    • the characteristics of the activity triggered by the membrane extract
    • are quite different to that of cytosol (Fig. 2).
 Using an unbiased biochemical purification method, we demonstrated that
  •  calmodulin and PKC directly modulate the exocytotic machinery downstream of Ca2+ entry
  • they signal through membrane-attached molecules to increase exocytosis.
 These targets include integral and peripheral membrane proteins, and cytosolic proteins that have a significant
membrane-bound pool.  The modest stimulation by calmodulin and PKC on secretion might suggest a regulatory
role. However, it is also possible that some intermediates in their signaling pathways are in limiting amounts in the
cell ghosts, so that their full effects were not observed. Half-maximal stimulation was obtained at
  • about 3 nM for PKC and
  • at about 75 nM for calmodulin.
This is consistent with an enzymatic role for PKC, and predicts a high-affinity interaction between
  • calmodulin and its substrate protein.
 Ca2+ regulates exocytosis at many different levels. Prior studies indicated that Ca2+ signaling occurs in

  • the priming steps as well
  • as in triggering steps (49, 50).
Our priming triggering protocol 
  1. does not allow Ca2+-dependent priming events to be assayed, as EGTA is present in the priming reaction.
  2. a different approach revealed the existence of both high and low Ca2+-dependent processes (Fig. 2).
  3. this analysis indicated that late triggering events require high [Ca2+], whereas
  4. early priming events require low [Ca2+]. If, as proposed, there is
a pronounced intracellular spatial and temporal [Ca2+] gradient from
  • the point of Ca2+ entry during depolarization (51),
  • perhaps triggered events occur closer to the point of Ca2+ entry,
  • while Ca2+-dependent priming events occur further away from the point of Ca2+ entry.
Fig 2A. measurements of range of [Ca2+]total - average [Ca2+]free values._page_004
Fig. 2B. measurements of range of [Ca2+] total - average [Ca2+]free values_edited-1
Distinct Ca2+ sensors at these stages might be appropriately tuned to different [Ca2+] to handle different tasks.
By analyzing the Ca2+ sensitivity of calmodulin-and PKC-stimulated release, we addressed the question of
  • whether calmodulin and PKC plays an early or a late role in vesicle release.
  •  they both require relatively high [Ca2+] (Fig. 8B),
  • implying that calmodulin and PKC both mediate late triggering events, consistent with some earlier reports
    (34, 52, 53).

In addition, it is interesting to note that PKC does not alter the calcium sensitivity of release in cracked cells, in contrast

to observations from the chick ciliary ganglion (36). Therefore, in contrast to previous electrophysiological studies (28),
we are able to limit the possible modes of PKC action in our system to an increase in the readily releasable vesicle pool or
release sites, or an enhancement of the probability of release of individual vesicles upon Ca2+ influx.
The experiments assaying the calcium sensitivity of release (Figs. 2, 5, and 8) demonstrated
  • a drop in release at very high [Ca2+].

FIG. 5 calmodulin action_page_005

FIG. 8. PKC and calmodulin stimulate... the late triggering reaction_page_006
This decline in release at high [Ca2+] has been previously reported (49, 51), and may represent
  • the true Ca2+ sensitivity of the Ca2+-sensing mechanism inside cells.

However, in our system, it could also be due to the activation of a variety of Ca2+ -activated proteases, as experiments are usually performed in the presence of crude extracts, which include unsequestered proteases.

What might the molecular targets of PKC and calmodulin be? An obvious calmodulin target molecule is CaMKII.
  • but calmodulin’s effect on exocytosis is ATP-independent, rendering the involvement of a kinase unlikely.
 Calmodulin has also been shown to associate with
  • synaptic vesicles in a Ca2+-dependent fashion through synaptotagmin (54),
  • probably by binding to its C-terminal tail (55), and to promote Rab3A dissociation from synaptic vesicles (56).
  • However, there was little calcium-dependent binding of calmodulin to synaptotagmin
    • either on synaptic vesicles, in a bead binding assay with recombinant proteins,
    • or in a calmodulin overlay (data not shown).

In addition, using immobilized calmodulin, we did not see

  • significant Ca2+-dependent pull-down of synaptotagmin or Rab3A from rat brain extract (data not shown).
Recent work has suggested three other candidate targets for calmodulin, Munc13, Pollux, and CRAG (57).
  • Pollux has similarity to a portion of a yeast Rab GTPase-activating protein, while
  • CRAG is related to Rab3 GTPase exchange proteins.
Further work is required to investigate the role of their interactions with calmodulin in vivo.
The recent report that calmodulin mediates yeast vacuole fusion (24) is intriguing, as it raises the possibility that
  • calmodulin, a highly conserved ubiquitous molecule,
    • may mediate many membrane trafficking events.

It is not yet known if

  • the effector molecule of calmodulin is conserved or variable across species and different trafficking steps.

It is enticing to propose a model for Ca2+ sensing whereby

  • calmodulin is a high affinity Ca2+ sensor for both constitutive and regulated membrane fusion.
  1. In the case of constitutive fusion, calmodulin may be the predominant Ca2+ sensor.
  2. In the case of slow, non-local exocytosis of large dense core granules, an additional requirement for
  3. the concerted actions of other molecule(s) that are better tuned to intermediate rises in [Ca2+] might exist.
At the highly localized sites of fast exocytosis of small clear vesicles where high [Ca2+] is reached,
  • specialized low affinity sensor(s) are likely required
  • in addition to calmodulin to achieve membrane fusion.

Therefore, although calmodulin participates in multiple types of vesicle fusion,

  • the impact of Ca2+ sensing by calmodulin on vesicle release likely varies.
Due to the fact that calmodulin binding to some proteins can be modulated by PKC phosphorylation, one might suspect
  • PKC action on exocytosis proceeds through a calmodulin-dependent pathway.
  • but the effects of calmodulin and PKC are additive within our system,
    • suggesting that PKC does not act by releasing calmodulin from a substrate
      • that functions as a calmodulin storage protein.
How Ca2+ regulates presynaptic vesicle release has been an open question for many years. By

  • identifying calmodulin and PKC as modulators of Ca21-regulated exocytosis and clarifying their functions,
  • we have extended our knowledge of the release process.

While the basic machinery of membrane fusion is becoming better understood,

  • the multiple effects of Ca2+ on exocytosis remain to be elucidated at the molecular level.

In addition, the ways that Ca2+ regulation may be important to

  • the mechanisms of synaptic plasticity in the central nervous system

EXPERIMENTAL PROCEDURES

Materials
Rat Brain Cytosol Preparation
Membrane EGTA Extract Preparation

Cracked Cell Assay

PC12 cells were maintained and [3H]NE labeled as described previously (11). Labeled cells were harvested by pipetting with ice-cold potassium glutamate buffer (50 mM Hepes, pH 7.2, 105 mM potassium glutamate, 20 mM potassium acetate, 2 mM EGTA) containing 0.1% bovine serum albumin. Subsequent manipulations were carried out at 0–4 °C. Labeled cells (1–1.5 ml/dish) were mechanically permeabilized passage through a stainless steel homogenizer. The cracked cells were adjusted to 11 mM EGTA and

  • incubated on ice for 0.5–3 h, followed by three washes in which
  • the cells were centrifuged at 800 3 g for 5 min and
  • resuspended in potassium glutamate buffer containing 0.1% bovine serum albumin.

Composite Assay 

Each release reaction contains 0.5–1 million cracked cells, 1.5 mM free Ca2+, 2 mM MgATP,
and the protein solution to be tested in potassium glutamate buffer. Release reactions were initiated
by incubation at 30 °C and terminated by returning to ice. The supernatant of each reaction was
isolated by centrifugation at 2,500 3 g for 30 min at 4 °C, and the

  • released [3H]NE was quantified by scintillation counting (Beckman LS6000IC).

Cell pellets were dissolved in 1% Triton X-100, 0.02% azide and similarly counted. NE release

  • was calculated as a percentage of total [3H] in the supernatant.

Priming Assay

A priming reaction contains about

  • 1–2 million cracked cells,
  • 2 mM MgATP, and
  • the protein solution to be tested.
  • Ca2+ is omitted.

The primed cells were spun down, washed once with fresh potassium glutamate buffer, and

  • distributed into two triggering reactions, each containing
  • rat brain cytosol and free Ca2+
  • The triggering reaction was performed at 30 °C for 3 min, and
  • the NE release was measured
    • as in a composite assay.

Triggering Assay

Cracked cells were primed …, centrifuged, washed …, and

distributed into triggering reactions containing

  • 1.5 mM free Ca2+ and the protein solution 

To inhibit any ATP dependent activity in the triggering reaction,  an

  • ATP depletion system of
    1. hexokinase
    2. MgCl2,
    3. glucose or
  • a non-hydrolyzable ATP analogue AMPPNP

was added into the triggering reaction. NE release was measured as above.

Free Ca2+ Concentration Determination

The range of Ca2+free in the release reaction (Fig. 2B) was achieved

  • by adding Ca2+ into potassium glutamate buffer to reach final [Ca2+] total values of
    • 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 1.9, and 2.0 mM.
  • The pH of the reaction was 7.24 when no Ca2+ was added and
  • 7.04 when 2.0 mM Ca2+ was added
    • in the absence of protein extracts or cracked cells.
Fig. 2B. measurements of range of [Ca2+] total - average [Ca2+]free values_edited-1
Fig. 2B.   The range of [Ca21]free in the release reaction (Fig. 2B)
Free Ca2+ concentrations were determined using video microscopic
measurements of fura-2 fluorescence
 (41). [Ca2+]free was calculated from the equation
  • [Ca2+]free 5 Kd*3 (R 2 Rmin)/(Rmax 2 R) (42).
The values of Rmin, Rmax, and Kd* were determined in the following solutions: 
potassium glutamate buffer (PGB) containing
  • 8 x 3 10^6 cracked cells/ml, 2 mM MgATP (PGB+CC)
1) Rmin:  PGB+CC and 10 mM additional EGTA;
2) Rmax: PBG+CC, and 10 mM total Ca2+;
3) Kd*: PGB+CC, 28 mM additional EGTA, and 18 mM total Ca2+, pH 7.2
([Ca2+]free 5 = 169 nM, determined in the absence of cells and MgATP
  • based on fura-2 calibration in cell-free solutions).
These solutions were
  1. incubated at 37 °C ,
  2. mixed with fura-2 pentapotassium salt
    (100 mM; Molecular Probes, Eugene, OR), and
  3. imaged.
This procedure allowed us to take into account
  • changes in fura-2 properties
  • caused by the presence of
    • permeabilized cells.
Duplicate measurements of the above range of [Ca2+] total gave
  • the following average [Ca2+] free values:
  • 106, 146, 277, 462, 971, 1468, 1847, and 2484 nM.

Purification of Active Proteins

All procedures were carried out at 4 °C or on ice. Membrane
EGTA extract of one or two bovine brain(s) was

  1. filtered through cheesecloth and
  2. loaded overnight onto a column packed with DEAE-Sepharose
    CL-6B beads (Amersham Pharmacia Biotech).

The column was then

  1. washed with
    (20 mM Hepes, pH 7.5, 0.25 mM sucrose, 2 mM EGTA, 1 mM dithiothreitol) and 
  2. step eluted with 10 column volumes of elution buffer
    (20 mM Hepes, pH 7.5, 2 mM EGTA, 400 mM KCl, 1 mM dithiothreitol).
    100 ml of every other fraction was
  3. dialyzed overnight into PGB, and
  4. tested in a composite release assay for activity.
  • The active fractions were pooled and dialyzed into zero salt buffer
    (20 mM Hepes, pH 7.5, 2 mM EGTA) and
  • batch bound to 10 ml of Affi-Gel Blue beads (Bio-Rad) or DyeMatrex-Green A beads (Amicon)

Blue beads were used in earlier experiments, and Green beads were used later to

  • specifically deplete CAPS, which was known to bind to Green beads (9).

The unbound material was

  1. collected,
  2. concentrated to about 2 ml using a Centriprep-10 (Amicon), and
  3. loaded onto a 120-ml HiPrep Sephacryl S-200 gel filtration column
    (Amersham Pharmacia Biotech).
Samples were run on the S-200 column in PGB at a flow rate of 7 ml/h.
  • 10–50 ml of every other fraction was tested for
    • activity in the cracked cell composite assay, and
  • two peaks of activity were observed (Fig. 3).

FIG. 3. Gel filtration chromatography reveals two stimulatory_page_004

The first peak of activity had a predicted molecular mass of 85 kDa.
The corresponding material was

  • adjusted to 10 mM potassium phosphate concentration (pH 7.2) and
  • loaded onto a 1-ml column packed with hydroxyapatite Bio-Gel HT
    (Bio-Rad).

The bound material was

  • eluted with a linear K-PO4 gradient from 10 to 500 mM (pH 7.2)
  •  at a flow rate of about 0.1 ml/min, and
  • 0.4–0.5-ml fractions were collected.
  •  each fraction was dialyzed into PGB and
  • tested for activity.

The fractions were also analyzed by

  • SDS-PAGE and silver staining (Sigma silver stain kit).

The active material was concentrated and resolved

  • on an 8% poly-acrylamide gel.

Two Coomassie-stained protein bands that matched the activity profile (Fig. 6)

  • were excised from the gel,
  • sequenced by the Stanford PAN facility.

FIG. 6. Purification of the high molecular weight active factor_page_001

The two polypeptide sequences obtained from the upper band were:

  1. LLNQEEGEYYNVPIXEGD
  2. IRSTLNPRWDESFT.

The only bovine protein that contains both polypeptides is PKCa.
The four polypeptide sequences obtained from the lower band were:

  1. YELTGKFERLIVGLMRPPAY,
  2. LIEILASRTNEQIHQLVAA,
  3. MLVVLLQGTREEDDVVSEDL, and
  4. EMSGDVRDVFVAIVQSVK.

Based on these sequences, the protein band was

  • unambiguously identified to be bovine annexin VI.

The second S-200 peak has a predicted molecular mass of 25 kDa.
The corresponding material was

  • dialyzed into zero salt buffer
    (20 mM Tris, pH 7.5, 1 mM EGTA) and
  • injected onto a Mono-Q HR 5/5 FPLC column
    (Pharmacia).

The FPLC run was performed at 18 °C at 1 ml/min and

  • 1-ml fractions were collected
  • with a linear salt gradient from 0 to 1 M KCl over 71 ml.

The fractions containing proteins (determined by A280) were

  • dialyzed into PGB and
  • tested in the cracked cell assay.

Western Blot

Anti-calmodulin antibody and anti-PKC antibody were used, and

  • ECL (Amersham) was used for detection.

RESULTS

A Membrane EGTA Extract Supports NE Release 

Brain cytosol, prepared as the supernatant of the brain homogenate,
  • effectively stimulates NE release
  • in the cracked cell assay (Fig. 1)
    as previously shown (9). 

Fig. 1 EGTA extract can support NE release_page_003_edited-2

We wondered whether crude extracts other than cytosol
  • could support NE release, and we focused on
  • extractable peripheral membrane proteins.
We found that a salt or EGTA extract of brain membranes,
membranes defined as the
  • 100,000 3 g pellet of the crude homogenate,
  • reconstituted secretion in the absence of cytosol.
  • the salt extract only slightly enhanced NE release
    above background (data not shown), the 
EGTA extract not only stimulated NE release to a high level,
  • similar to that supported by cytosol, but also
  • had a higher specific activity than cytosol (Fig. 1). 
Fig. 1 EGTA extract can support NE release_page_003_edited-3
FIG. 1. The EGTA extract of brain membranes can support NE release in the absence of cytosol. Rat brain membrane EGTA extract (closed triangles) and rat brain cytosol (closed squares) were prepared as described under “Experimental Procedures.” NE release was measured in a composite reaction mixture of cracked cells, MgATP, Ca2+, and the indicated amount of crude extracts.
The ability of the membrane EGTA extract to support secretion is consistent with the fact that
  • following cracking, the cells are immediately extracted with EGTA, and are presumably
  • devoid of most membrane EGTA-extractable factors.

This also suggests that these factors, some of which are probably

  • Ca2+-dependent membrane-associating proteins,
  • participate in Ca2+- triggered exocytosis.

The Membrane EGTA Extract Is Enriched in Triggering Fators

NE release in cracked cells can be resolved into two sequential stages,
  • an ATP-dependent priming stage and
  • an ATP-independent Ca21-dependent triggering stage (11), and
  • proteins can be tested for activity in either stage.
An effect in priming indicates
  1. an early role for the protein, and
  2. an effect in triggering a late ATP-independent role.
Since the protein composition of the
  • membrane EGTA extract and cytosol are different,
we tested whether they had different activities
  • in the priming stage versus the triggering stage.
We found that the membrane EGTA extract is enriched in factors that
  • act during triggering stage of NE releaseas
  • the same amount of protein from the membrane EGTA extract as cytosol
  • gave a higher stimulation in the triggering assay, but
  • not in the priming assay (Fig. 2A). 

Fig 2A. measurements of range of [Ca2+]total - average [Ca2+]free values._page_004

Regular cytosol is prepared in a buffer containing 2 mM EGTA, and thus

  • presumably contains some of the proteins present in the membrane EGTA extract.
Cytosol prepared in the absence of EGTA showed an even lower specific activity
  • in the triggering assay compared with regular cytosol (Fig. 2A).

Identification of Calmodulin as an Active Triggering Factor in the EGTA Extract

Biochemical fractionation of the bovine brain membrane EGTA extract was carried out

  • to identify the active components capable of reconstituting NE release.

Activity was assayed in a composite reaction mixture containing

  • cracked cells,
  • ATP,
  • Ca2+, and
  • the test protein(s).

Except for the presence of bovine serum albumin in the basal buffer,

  • no other proteins were added to the cell ghosts except for the test protein(s).

Initial tests indicated that at least

  1. part of the activity in the membrane EGTA extract binds to and
  2. can be efficiently eluted from an anion exchanger and hydroxyapatite resin,
  3. but does not bind to Amicon color resins.

The starting material was, therefore, sequentially purified using

  • DEAE, Affi-Gel Blue (or Matrex Green-A), and gel filtration chromotography.

Gel filtration fractionation indicated the presence of two peaks of activity with

  • predicted molecular masses of 25 and 85 kDa, respectively (Fig. 3).

FIG. 3. Gel filtration chromatography reveals two stimulatory_page_004

FIG. 3. Gel filtration chromatography reveals two stimulatory factors in the membrane EGTA extract.

In order to purify the active component(s) in the membrane EGTA extract, the crude extract from one bovine brain was fractionated chromatographically (see Experimental Procedures” for details). Fractions from a Sephacryl S-200 gel filtration column were tested for their activity in stimulating NE release in the composite assay. The two activity peaks have predicted molecular masses of 85 and 25 kDa, respectively. The arrows indicate the retention volume of standard proteins run on the same column.

The low molecular weight active factor was purified to homogeneity, as judged by a

  • Coomassie-stained SDS-PAGE gel, after a subsequent Mono-Q fractionation (Fig. 4).

FIG. 4. The low molecular weight active factor is calmodulin_page_004

FIG. 4. The low molecular wen.ight active factor is calmodulin

A, the  membrane EGTA extract from one bovine brain (Start) was subjected to sequential fractionation on DEAE, Blue A, and
Sephacryl S-200 columns. The pooled material containing the activity after each chromotographic step was analyzed by SDS-
PAGE and Coomassie staining. The arrowheads indicate the presence of calmodulin in all the lanes. Calmodulin shows a
mobility shift depending on whether or not Ca2+ is present during electrophoresis (see panel C).
B, the active material  pooled from Sephacryl S-200 was fractionated on a Mono-Q FPLC column and the fractions
(5 ml/fraction) were tested for activity in a composite assay. The activity peak is shown.
C, the active Mono-Q fractions (5 ml/fraction) were subjected to SDS-PAGE in the presence of 1 mM EGTA or 0.1 mM Ca2+,
and the gels stained with Coomassie Blue.
D, fraction 47 (1 ml) was probed by Western blotting with a monoclonal anti-calmodulin antibody. No Ca2+ or EGTA was
added during SDS-PAGE.

We reasoned that the protein might be calmodulin (43) based on the following:

1) It is a relatively small protein (14–18 kDa) that is abundant in the
starting extract (Fig. 4A).
2) It elutes at a very high salt concentration (0.41 M KCl) on the
Mono-Q column.
3) It stains negatively in silver stain (data not shown).
4) Its electrophoretic mobility shifts depending on the presence or
absence of Ca21 (Fig. 4C).

A Western blot with an anti-calmodulin monoclonal antibody gave a
positive signal (Fig. 4D), confirming our prediction.

Properties of Calmodulin-stimulated Exocytosis

We used commercial calmodulin or bacterially expressed recombinant calmodulin to confirm our purification result; both sources of authentic calmodulin stimulated NE release as expected. Moreover, we found that calmodulin stimulates secretion in a triggering assay as well as in a composite assay (Fig. 5A).

FIG. 5A calmodulin action_page 5

The half-maximal increase was at 75 nM (250 ng/200 ml) final calmodulin concentration. This is within the broad
range of affinities between calmodulin and its various targets and suggests that the interaction between
calmodulin and its target molecule in exocytosis is in the physiological range. When the triggering reaction was
performed at different Ca2+ concentrations, calmodulin increased NE release only at high [Ca2+] (0.4 – 2 mM)
similar to the crude EGTA extract (Fig. 5B),

FIG. 5B calmodulin action_page_5

suggesting that calmodulin contributes to the triggering activity of the membrane EGTA extract.  Calmodulin’s affinity for Ca2+ has
been  reported to be around 1 mM (25),

  • consistent with the Ca2+ requirement for
  • calmodulin-stimulated secretion that we observed.

FIG. 5 calmodulin action_page_005

FIG. 5. Calmodulin stimulates NE release in the triggering stage.
A, calmodulin (obtained from Sigma) increased NE release in the
triggering assay in a dose-dependent fashion, in the absence of ATP
or any other cytosolic proteins. In this particular experiment, the
maximal release achieved by addition of rat brain cytosol was 46.5%.

B, the triggering assay was performed with different concentrations
of free Ca2+. Calmodulin (3 mg bacterially expressed recombinant
protein; closed squares) increased NE release with a similar Ca2+
sensitivity to rat brain membrane EGTA extract (10 mg; closed
triangles), as compared with conditions in which no protein was
added (open squares).

Western analysis with commercial protein as standards indicated that calmodulin 

  •  constitutes about 5% of total proteins in the rat brain membrane EGTA extract
  • and about 2% of total proteins in the rat brain cytosol (data not shown).

In addition, a significant amount of calmodulin appears to be left

  • in the washed cell ghosts (data not shown).

Based on the activity of saturating levels of

  • pure calmodulin (releasing 6–10% of total [3H]NE)
  • and crude EGTA extract (releasing ;45% of total [3H]NE),

we estimated that

  • calmodulin accounts for 13–22% of total activity of the extract.

Consistent with this,

  • a high affinity calmodulin-binding peptide
    (CaMKIIa(291–312) (44), used at 5 mM) and
  • an anti-calmodulin antibody (2 mg/200 ml)
  • inhibited about 20% of the membrane EGTA extract-stimulated release
    (6.7 mg of extract added; data not shown).

We showed that calmodulin increased NE release

  • in the triggering stage.

Since regular triggering reactions were performed

  • in the absence of any added ATP,

this suggests that

  • calmodulin enhanced secretion in an ATP-independent fashion.

Furthermore, residual ATP in the cell ghosts did not play a role, since

  •  addition of a hexokinase ATP depletion system that
  • can deplete millimolar concentrations of ATP
    • within a few minutes (11) had little effect, as did
    • addition of 5 mM AMPPNP,
  • which blocks ATP-dependent enzymatic activity (Fig.8A).

Therefore, we ruled out the possibility that a kinase mediates calmodulin’s effect.

FIG. 8. PKC and calmodulin stimulate... the late triggering reaction_page_006

FIG. 8. PKC and calmodulin stimulate the late triggering reaction in
an ATP-dependent and ATP-independent manner respectively.
A, triggering assays were performed to test the activity of calmodulin
(recombinant; black bars) and PKC (purified rat brain PKC from
Calbiochem; shaded bars) in the absence of ATP. A regular triggering
assay is done in the absence of ATP (2ATP). To deplete residual ATP
in the cells, hexokinase-based ATP depletion was employed (1Hexo).
Alternatively, 5 mM AMP-PNP (1AMP-PNP) was added in the triggering
reaction. Under all three conditions, calmodulin increased release
as compared with the background (buffer only; white bars), whereas
PKC did not.
B, NE release in a composite assay was measured with varying
concentrations of free Ca2+ in the presence of 10 mg of calmodulin
(recombinant; closed triangles), 70 ng of PKC  (purified rat brain PKC
from Calbiochem; closed squares), or buffer only (open squares).

A series of calmodulin mutants from Paramecium and chicken were tested

  • for their ability to enhance Ca2+-stimulated secretion, and
  • none of the mutations abolished the calmodulin effect (data not shown).

These mutations include

  • S101F, M145V, E54K, G40E/D50N, V35I/D50N within Paramecium
  • calmodulin (45), and M124Q, M51A/V55A, and M51A/V55A/L32A
    within chicken calmodulin (46, 47).

The Paramecium calmodulin mutants are the result of

  • naturally occurring mutations that result in aberrations in their behavior.

These mutants can be grouped into two categories according to their
behavior, reflecting their loss of either

  1. a Ca2+-dependent Na1 current
     (calmodulin N-terminal lobe mutants: E54K, G40E/D50N, and
     V35I/D50N) or
  2. a Ca21-dependent K1 current
    (calmodulin C-terminal lobe mutants: S101F and M145V) (45).

The chicken calmodulin mutants have been shown to

  • differentially activate myosin light chain kinase
    (M124Q, M51A/V55A, and M51A/V55A/L32A),
    CaMKII (M124Q),  
    and CaMKIV (M124Q),

and the mutated residues are thought to be important in

  • defining calmodulin’s binding specificity (46, 47).

Our finding that these mutant calmodulins can stimulate exocytosis suggests that

  • calmodulin-binding domains similar to those of Paramecium Ca2+/calmodulin-dependent
    ion channels, myosin light chain kinase, CaMKII, and CaMKIV,
  • are unlikely to mediate release utilizing the conserved SNARE fusion machinery, as they
  • could be completely abolished by addition of exogenous syntaxin H3 domains (data not shown).
  • the same molecular pathway was not activated, since their effects were additive (data not shown).

 

Acknowledgments
We thank Diana Bautista and Dr. Richard S.Lewis for generous help
with [Ca21]free determination; Dr. Ching Kung for providing the Paramecium calmodulin
mutants, and Dr. Anthony R. Means for providing the chicken calmodulin mutants. We also
thank Dr. Jesse C. Hay for the initial setup of the cracked cell assay, and Dr. Suzie J.
Scales for helpful comments on the manuscript.

REFERENCES

1. Calakos, N., and Scheller, R. H. (1996) Physiol. Rev. 76, 1–29
2. Su¨ dhof, T. C. (1995) Nature 375, 645–653
3. Zucker, R. S. (1996) Neuron 17, 1049–1055
4. Hanson, P. I., Heuser, J. E., and Jahn, R. (1997) Curr. Opin. Neurobiol. 7, 310–315
5. Chen, Y. A., Scales, S. J., Patel, S. M., Doung, Y.-C., and Scheller, R. H. (1999) Cell 97, 165–174
6. Neher, E., and Zucker, R. S. (1993) Neuron 10, 21–30
7. Kamiya, H., and Zucker, R. S. (1994) Nature 371, 603–606
SOURCE

Other related articles published in this Open Access Online Scientific Journal include the following:

The role of ion channels in Na(+)-K(+)-ATPase: regulation of ion transport across the plasma membrane has been studies by our Team in 2012 and 2013. Chiefly, our sources of inspiration were the following:

1. 2013 Nobel work on vesicles and calcium flux at the neuromuscular junction Machinery Regulating Vesicle Traffic, A Major Transport System in our Cells The 2013 Nobel Prize in Physiology or Medicine is awarded to Dr. James E. Rothman, Dr. Randy W. Schekman and Dr. Thomas C. Südhof

  • for their discoveries of machinery regulating vesicle traffic,
  • a major transport system in our cells.

This represents a paradigm shift in our understanding of how the eukaryotic cell, with its complex internal compartmentalization, organizes

  • the routing of molecules packaged in vesicles
  • to various intracellular destinations,
  • as well as to the outside of the cell

Specificity in the delivery of molecular cargo is essential for cell function and survival.

http://www.nobelprize.org/nobel_prizes/medicine/laureates/2013/advanced-medicineprize2013.pdf

Synaptotagmin functions as a Calcium Sensor: How Calcium Ions Regulate the fusion of vesicles with
cell membranes during Neurotransmission

Larry H Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2013/09/10/synaptotagmin-functions-as-a-calcium-sensor-
how-calcium-ions-regulate-the-fusion-of-vesicles-with-cell-membranes-during-neurotransmission/

2. Perspectives on Nitric Oxide in Disease Mechanisms

available on Kindle Store @ Amazon.com

http://www.amazon.com/dp/B00DINFFYC

http://pharmaceuticalintelligence.com/biomed-e-books/series-a-e-books-on-cardiovascular-diseases/
perspectives-on-nitric-oxide-in-disease-mechanisms-v2/

3. Professor David Lichtstein, Hebrew University of Jerusalem, Dean, School of Medicine

Lichtstein’s main research focus is the regulation of ion transport across the plasma membrane of eukaryotic cells.

His work led to the discovery that specific steroids that have crucial roles, as

  • the regulation of cell viability,
  • heart contractility,
  • blood pressure and
  • brain function.

His research has implications for the fundamental understanding of body functions,

  • as well as for several pathological states such as
    • heart failure, hypertension
    • and neurological and psychiatric diseases.

Physiologist, Professor Lichtstein, Chair in Heart Studies at The Hebrew University elected
Dean of the Faculty of Medicine at The Hebrew University of Jerusalem

Reporter: Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2013/12/18/physiologist-professor-lichtstein-chair-in-heart-studies-
at-the-hebrew-university-elected-dean-of-the-faculty-of-medicine-at-the-hebrew-university-of-jerusalem/

4. Professor Roger J. Hajjar, MD at Mount Sinai School of Medicine

Calcium Cycling (ATPase Pump) in Cardiac Gene Therapy: Inhalable Gene Therapy for Pulmonary Arterial Hypertension
and Percutaneous Intra-coronary Artery Infusion for Heart Failure: Contributions by Roger J. Hajjar, MD

Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2013/08/01/calcium-molecule-in-cardiac-gene-therapy-inhalable-gene-therapy-for-
pulmonary-arterial-hypertension-and-percutaneous-intra-coronary-artery-infusion-for-heart-failure-contributions-by-roger-j-hajjar/

5.            Seminal Curations by Dr. Aviva Lev-Ari on Genetics and Genomics of Cardiovascular Diseases with a focus on Conduction and Cardiac Contractility

Aviva Lev-Ari, PhD, RN

Aviva Lev-Ari, PhD, RN

Aviva Lev-Ari, PhD, RN and Larry H. Bernstein, MD, FCAP

Justin Pearlman, MD, PhD, FACC, Larry H Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN

6. Atherosclerosis Independence: Genetic Polymorphisms of Ion Channels Role in the Pathogenesis of Coronary Microvascular Dysfunction and Myocardial Ischemia (Coronary Artery Disease (CAD))

Larry H Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2013/12/21/genetic-polymorphisms-of-ion-channels-have-a-role-in-the-pathogenesis-of-coronary-microvascular-dysfunction-and-ischemic-heart-disease/

This study presents  the possible correlation between Myocardial Ischemia (Coronary Artery Disease (CAD)) aka Ischemic Heart Disease (IHD) and single-nucleotide polymorphisms (SNPs) genes encoding several regulators involved in Coronary Blood Flow Regulation (CBFR), including

  • ion channels acting in vascular smooth muscle and/or
  • endothelial cells of coronary arteries.

They completely analyzed exon 3 of both KCNJ8 and KCNJ11 genes (Kir6.1 and Kir6.2 subunit, respectively) as well as

  • the whole coding region of KCN5A gene (Kv1.5 channel).

The work suggests certain genetic polymorphisms may represent a non-modifiable protective factor that could be

  • used to identify individuals at relatively low-risk for cardiovascular disease
    • an independent protective role of the
    • rs5215_GG against developing CAD and
    • a trend for rs5219_AA to be associated with protection against coronary microvascular dysfunction

Other related articles published on this Open Access Online Scientific Journal include the following:

ION CHANNEL and Cardiovascular Diseases

http://pharmaceuticalintelligence.com/?s=Ion+Channel

Calcium Role in Cardiovascular Diseases

Part I: Identification of Biomarkers that are Related to the Actin Cytoskeleton
Larry H Bernstein, MD, FCAP
http://pharmaceuticalintelligence.com/2012/12/10/identification-of-biomarkers-
that-are-related-to-the-actin-cytoskeleton/

Part II: Role of Calcium, the Actin Skeleton, and Lipid Structures in Signaling and Cell Motility
Larry H. Bernstein, MD, FCAP, Stephen Williams, PhD and Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2013/08/26/role-of-calcium-the-actin-
skeleton-and-lipid-structures-in-signaling-and-cell-motility/

Part III: Renal Distal Tubular Ca2+ Exchange Mechanism in Health and Disease
Larry H. Bernstein, MD, FCAP, Stephen J. Williams, PhD
and Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2013/09/02/renal-distal-tubular-ca2-
exchange-mechanism-in-health-and-disease/

Part IV: The Centrality of Ca(2+) Signaling and Cytoskeleton Involving Calmodulin Kinases and
Ryanodine Receptors in Cardiac Failure, Arterial Smooth Muscle, Post-ischemic Arrhythmia,
Similarities and Differences, and Pharmaceutical Targets
Larry H Bernstein, MD, FCAP, Justin Pearlman, MD, PhD, FACC and Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2013/09/08/the-centrality-of-ca2-signaling-and-cytoskeleton-
involving-calmodulin-kinases-and-ryanodine-receptors-in-cardiac-failure-arterial-smooth-muscle-
post-ischemic-arrhythmia-similarities-and-differen/

Part V: Ca2+-Stimulated Exocytosis:  The Role of Calmodulin and Protein Kinase C in Ca2+ Regulation of Hormone and Neurotransmitter

Larry H Bernstein, MD, FCAP
and
Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2013/12/23/calmodulin-and-protein-kinase-c-drive-the-ca2-regulation-of-hormone-and-neurotransmitter-release-that-triggers-ca2-stimulated-exocytosis/

Part VI: Calcium Cycling (ATPase Pump) in Cardiac Gene Therapy: Inhalable Gene Therapy for Pulmonary

Arterial Hypertension and Percutaneous Intra-coronary Artery Infusion for Heart Failure: Contributions by Roger J. Hajjar, MD
Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2013/08/01/calcium-molecule-in-cardiac-gene-therapy-inhalable-gene-therapy-
for-pulmonary-arterial-hypertension-and-percutaneous-intra-coronary-artery-infusion-for-heart-failure-contributions-by-roger-j-hajjar/

Part VII: Cardiac Contractility & Myocardium Performance: Ventricular Arrhythmias and Non-ischemic Heart Failure –
Therapeutic Implications for Cardiomyocyte Ryanopathy (Calcium Release-related Contractile Dysfunction) and Catecholamine Responses
Justin Pearlman, MD, PhD, FACC, Larry H Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2013/08/28/cardiac-contractility-myocardium-performance-ventricular-arrhythmias-
and-non-ischemic-heart-failure-therapeutic-implications-for-cardiomyocyte-ryanopathy-calcium-release-related-contractile/

Part VIII: Disruption of Calcium Homeostasis: Cardiomyocytes and Vascular Smooth Muscle Cells:
The Cardiac and Cardiovascular Calcium Signaling Mechanism
Justin Pearlman, MD, PhD, FACC, Larry H Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2013/09/12/disruption-of-calcium-homeostasis-cardiomyocytes-and-vascular-smooth-
muscle-cells-the-cardiac-and-cardiovascular-calcium-signaling-mechanism/

Part IX: Calcium-Channel Blockers, Calcium Release-related Contractile Dysfunction
(Ryanopathy) and Calcium as Neurotransmitter Sensor
Justin Pearlman, MD, PhD, FACC, Larry H Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2013/09/16/calcium-channel-blocker-calcium-as-neurotransmitter-sensor-
and-calcium-release-related-contractile-dysfunction-ryanopathy/

Part X: Synaptotagmin functions as a Calcium Sensor: How Calcium Ions Regulate the fusion of
vesicles with cell membranes during Neurotransmission
Larry H Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2013/09/10/synaptotagmin-functions-as-a-calcium-sensor-how-calcium-ions-
regulate-the-fusion-of-vesicles-with-cell-membranes-during-neurotransmission/

Part XI: Sensors and Signaling in Oxidative Stress
Larry H. Bernstein, MD, FCAP
http://pharmaceuticalintelligence.com/2013/11/01/sensors-and-signaling-in-oxidative-stress/

Part XII: Atherosclerosis Independence: Genetic Polymorphisms of Ion Channels Role in the Pathogenesis of Coronary Microvascular Dysfunction and Myocardial Ischemia (Coronary Artery Disease (CAD))

Larry H Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN

http://pharmaceuticalintelligence.com/2013/12/21/genetic-polymorphisms-of-ion-channels-have-a-role-in-the-pathogenesis-of-coronary-microvascular-dysfunction-and-ischemic-heart-disease/

 

Mitochondria and its Role in Cardiovascular Diseases

Mitochondria and Oxidative Stress Role in Cardiovascular Diseases Reversal of Cardiac Mitochondrial Dysfunction
Larry H. Bernstein, MD, FCAP
http://pharmaceuticalintelligence.com/2013/04/14/reversal-of-cardiac-mitochondrial-dysfunction/

Calcium Signaling, Cardiac Mitochondria and Metabolic Syndrome
Larry H. Bernstein, MD, FCAP and Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2013/11/09/calcium-signaling-cardiac-mitochondria-and-metabolic-syndrome/

Mitochondrial Dysfunction and Cardiac Disorders
Larry H. Bernstein, MD, FCAP
http://pharmaceuticalintelligence.com/2013/04/14/mitochondrial-dysfunction-and-cardiac-disorders/

Mitochondrial Metabolism and Cardiac Function
Larry H. Bernstein, MD, FCAP
http://pharmaceuticalintelligence.com/2013/04/14/mitochondrial-metabolism-and-cardiac-function/

Mitochondria and Cardiovascular Disease: A Tribute to Richard Bing
Larry H. Bernstein, MD, FCAP
http://pharmaceuticalintelligence.com/2013/04/14/chapter-5-mitochondria-and-cardiovascular-disease/

MIT Scientists on Proteomics: All the Proteins in the Mitochondrial Matrix Identified
Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2013/02/03/mit-scientists-on-proteomics-all-the-proteins-
in-the-mitochondrial-matrix-identified/

Mitochondrial Dynamics and Cardiovascular Diseases
Ritu Saxena, Ph.D.
http://pharmaceuticalintelligence.com/2012/11/14/mitochondrial-dynamics-and-cardiovascular-diseases/

Mitochondrial Damage and Repair under Oxidative Stress
Larry H Bernstein, MD, FCAP
http://pharmaceuticalintelligence.com/2012/10/28/mitochondrial-damage-and-repair-under-oxidative-stress/

Nitric Oxide has a Ubiquitous Role in the Regulation of Glycolysis -with a Concomitant Influence on Mitochondrial Function
Larry H. Bernstein, MD, FACP
http://pharmaceuticalintelligence.com/2012/09/16/nitric-oxide-has-a-ubiquitous-role-in-the-regulation-of-
glycolysis-with-a-concomitant-influence-on-mitochondrial-function/

Mitochondrial Mechanisms of Disease in Diabetes Mellitus
Aviva Lev-Ari, PhD, RN
http://pharmaceuticalintelligence.com/2012/08/01/mitochondrial-mechanisms-of-disease-in-diabetes-mellitus/

Mitochondria Dysfunction and Cardiovascular Disease – Mitochondria: More than just the “Powerhouse of the Cell”
Ritu Saxena, PhD
http://pharmaceuticalintelligence.com/2012/07/09/mitochondria-more-than-just-the-powerhouse-of-the-cell/

Read Full Post »

« Newer Posts