Feeds:
Posts
Comments

Archive for the ‘Neurological Diseases’ Category


Gene Therapy could be a Boon to Alzheimer’s disease (AD): A first-in-human clinical trial proposed

Reporter: Dr. Premalata Pati, Ph.D., Postdoc

A recent research work performed by the Researchers at the University of California San Diego School of Medicine has shared their first-in-human Phase I clinical trial to assess the safety and viability of gene therapy to deliver a key protein into the brains of persons with Alzheimer’s Disease (AD) or Mild Cognitive Impairment (MCI), a condition that often precedes full-blown dementia.  

Mark Tuszynski, M.D., Ph.D., Professor of Neuroscience and Director of the Translational Neuroscience Institute at UC San Diego and team predicted that Gene therapy could be a boon to potential treatments for the disorders like AD and MCI.

The study provides an insight into the genetic source of these mental diseases.

The roots of mental disorders have remained an enigma for so many years. Alzheimer’s disease (AD) is an irreversible, progressive brain disorder that slowly destroys memory and thinking skills and, eventually, the ability to carry out the simplest tasks. AD is a neurodegenerative condition. A buildup of plaques and tangles in the brain, along with cell death, causes memory loss and cognitive decline. In most people with the disease, those with the late-onset type – symptoms first appear in their mid-60s. Alzheimer’s disease is the mostly appearing type of dementia in patients.

Drawing comparing a normal aged brain (left) and the brain of a person with Alzheimer’s (right).
Image Source: https://en.wikipedia.org/wiki/Alzheimer%27s_disease

What the study impart?

Despite decades of effort and billions of dollars of research investment, there are just mere two symptomatic treatments for AD. There is no cure or approved way to slow or stop the progression of the neurological disorder that afflicts more than 5 million Americans and is the sixth leading cause of death in the United States.

Prof. Tuszynski said gene therapy has been tested on multiple diseases and conditions, represents a different approach to a disease that requires new ways of thinking about the disease and new attempts at treatments.

The research team found that delivering the BDNF to the part of the brain that is affected earliest in Alzheimer’s disease; the entorhinal cortex and hippocampus – was able to protect from ongoing cell degeneration by reversing the loss of connections. “These trials were observed in aged rats, amyloid mice, and aged monkeys.”

The protein, called Brain-Derived Neurotrophic Factor or BDNF, a family of growth factors found in the Brain and Central Nervous System that support the survival of existing neurons and promote growth and differentiation of new neurons and synapses. BDNF is especially important in brain regions susceptible to degeneration in AD. It is normally produced throughout life in the entorhinal cortex, an important memory center in the brain and one of the first places where the effects of AD typically appear in the form of short-term memory loss. Persons with AD have diminished levels of BDNF.

However, BDNF is a large molecule and cannot pass through the Blood-Brain Barrier. As a solution, researchers will use gene therapy in which a harmless Adeno-Associated Virus (AAV2) is modified to carry the BDNF gene and injected directly into targeted regions of the brain, where researchers hope it will prompt the production of therapeutic BDNF in nearby cells.

Precautions were taken precisely in injecting the patient to avoid exposure to surrounding degenerating neurons since freely circulating BDNF can cause adverse effects, such as seizures or epileptic conditions.

The recent research and study speculate a safe and feasible assessment of the AAV2-BDNF pathway in humans. A previous gene therapy trial from 2001 to 2012 using AAV2 and a different protein called Nerve Growth Factor (NGF) was carried out by Prof. Tuszynski and team where they observed immense growth, axonal sprouting, and activation of functional markers in the brains of participants.

He also shared that “The BDNF gene therapy trial in AD represents an advancement over the earlier NGF trial, BDNF is a more potent growth factor than NGF for neural circuits that degenerate in AD. Besides, new methods for delivering BDNF will more effectively deliver and distribute it into the entorhinal cortex and hippocampus.”

The research team hopes that the three-year-long trial will recruit 12 participants with either diagnosed AD or MCI to receive AAV2-BDNF treatment, with another 12 persons serving as comparative controls over that period.

The researchers have plans to build on recent successes of gene therapy in other diseases, including a breakthrough success in the treatment of congenital weakness in infants (spinal muscular atrophy) and blindness (Leber Hereditary Optic Neuropathy, a form of retinitis pigmentosa).”

Main Source

https://www.universityofcalifornia.edu/news/could-gene-therapy-halt-progression-alzheimers-disease-first-human-clinical-trial-will-seek?utm_source=fiat-lux

Related Articles

https://pharmaceuticalintelligence.com/2016/04/21/alzheimers-disease-and-dm/
https://pharmaceuticalintelligence.com/2016/03/21/role-of-infectious-agent-in-alzheimers-disease/
https://pharmaceuticalintelligence.com/2016/02/15/alzheimers-disease-tau-art-thou-or-amyloid/

Read Full Post »


Two brothers with MEPAN Syndrome: A Rare Genetic Disorder

Reporter: Amandeep Kaur

In the early 40s, a married couple named Danny and Nikki, had normal pregnancy and delivered their first child in October 2011.  The couple was elated after the birth of Carson because they were uncertain about even conceiving a baby. Soon after birth, the parents started facing difficulty in feeding the newborn and had some wakeful nights, which they used to called “witching hours”. For initial six months, they were clueless that something was not correct with their infant. Shortly, they found issues in moving ability, sitting, and crawling with Carson. Their next half year went in visiting several behavioral specialists and pediatricians with no conclusion other than a suggestion that there is nothing to panic as children grow at different rates.

Later in early 2013, Caron was detected with cerebral palsy in a local regional center. The diagnosis was based on his disability to talk and delay in motor development. At the same time, Carson had his first MRI which showed no negative results. The parents convinced themselves that their child condition would be solved by therapies and thus started physical and occupational therapies. After two years, the couple gave birth to another boy child named Chase in 2013. Initially, there was nothing wrong with Chase as well. But after nine months, Chase was found to possess the same symptoms of delaying in motor development as his elder brother. It was expected that Chase may also be suffering from cerebral palsy. For around one year both boys went through enormous diagnostic tests starting from karyotyping, metabolic screen tests to diagnostic tests for Fragile X syndrome, lysosomal storage disorders, Friedreich ataxia and spinocerebellar ataxia. Gene panel tests for mitochondrial DNA and Oxidative phosphorylation (OXPHOS) deficiencies were also performed. No conclusion was drawn because each diagnostic test showed the negative results.

Over the years, the condition of boys was deteriorating as their movements became stiffer and ataxic, they were not able to crawl anymore. By the end of 2015, the boys had an MRI which showed some symmetric anomalies in their basal ganglia indicating a metabolic condition. The symptoms of Carson and Chase was not even explained by whole exome sequencing due to the absence of any positive result. The grievous journey of visits to neurologist, diagnostic tests and inconclusive results led the parents to rethink about anything happened erroneous due to them such as due to their lifestyle, insufficient intake of vitamins during pregnancy or exposure to toxic agents which left their sons in that situation.

During the diagnostic odyssey, Danny spent many restless and sleepless nights in searching PubMed for any recent cases with symptoms similar to his sons and eventually came across the NIH’s Undiagnosed Diseases Network (UDN), which gave a light of hope to the demoralized family. As soon as Danny discovered about the NIH’s Diseases Network, he gathered all the medical documents of both his sons and submitted the application. The submitted application in late 2015 got accepted a year later in December 2016 and they got their first appointment in early 2017 at the UDN site at Stanford. At Stanford, the boys had gone through whole-genome sequencing and some series of examinations which came back with inconclusive results. Finally, in February 2018, the family received some conclusive results which explained that the two boys suffer from MEPAN syndrome with pathogenic mutations in MECR gene.

  • MEPAN means Mitochondrial Enoyl CoA reductase Protein-Associated Neurodegeneration
  • MEPAN syndrome is a rare genetic neurological disorder
  • MEPAN syndrome is associated with symptoms of ataxia, optic atrophy and dystonia
  • The wild-type MECR gene encodes a mitochondrial protein which is involved in metabolic processes
  • The prevalence rate of MEPAN syndrome is 1 in 1 million
  • Currently, there are 17 patients of MEPAN syndrome worldwide

The symptoms of Carson and Chase of an early onset of motor development with no appropriate biomarkers and T-2 hyperintensity in the basal ganglia were matching with the seven known MEPAN patient at that time. The agonizing journey of five years concluded with diagnosis of rare genetic disorder.

Despite the advances in genetic testing and their low-cost, there are many families which still suffer and left undiagnostic for long years. To shorten the diagnostic journey of undiagnosed patients, the whole-exome and whole-genome sequencing can be used as a primary tool. There is need of more research to find appropriate treatments of genetic disorders and therapies to reduce the suffering of the patients and families. It is necessary to fill the gap between the researchers and clinicians to stimulate the development in diagnosis, treatment and drug development for rare genetic disorders.

The family started a foundation named “MEPAN Foundation” (https://www.mepan. org) to reach out to the world to educate people about the mutation in MECR gene. By creating awareness among the communities, clinicians, and researchers worldwide, the patients having rare genetic disorder can come closer and share their information to improve their condition and quality of life.

Reference: Danny Miller, The diagnostic odyssey: our family’s story, The American Journal of Human Genetics, Volume 108, Issue 2, 2021, Pages 217-218, ISSN 0002-9297, https://doi.org/10.1016/j.ajhg.2021.01.003 (https://www.sciencedirect.com/science/article/pii/S0002929721000033)

Sources:

https://www.variantyx.com/2020/02/26/in-silico-panel-expansion/

https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=EN&Expert=508093

https://www.mepan. org

Other related articles were published in this Open Access Online Scientific Journal, including the following:

Effect of mitochondrial stress on epigenetic modifiers

Larry H. Bernstein, MD, FCAP, Curator, LPBI

https://pharmaceuticalintelligence.com/2016/05/07/effect-of-mitochondrial-stress-on-epigenetic-modifiers/

The Three Parent Technique to Avoid Mitochondrial Disease in Embryo

Reporter and Curator: Dr. Sudipta Saha, Ph.D.

https://pharmaceuticalintelligence.com/2016/10/07/the-three-parent-technique-to-avoid-mitochondrial-disease-in-embryo/

New Insights into mtDNA, mitochondrial proteins, aging, and metabolic control

Larry H. Bernstein, MD, FCAP, Curator, LPBI

https://pharmaceuticalintelligence.com/2016/04/20/new-insights-into-mtdna-mitochondrial-proteins-aging-and-metabolic-control/

Mitochondrial Isocitrate Dehydrogenase and Variants

Writer and Curator: Larry H. Bernstein, MD, FCAP

https://pharmaceuticalintelligence.com/2015/04/02/mitochondrial-isocitrate-dehydrogenase-and-variants/

Update on mitochondrial function, respiration, and associated disorders

Larry H. Benstein, MD, FCAP, Gurator and writer

https://pharmaceuticalintelligence.com/2014/07/08/update-on-mitochondrial-function-respiration-and-associated-disorders/

Read Full Post »


Dysregulation of ncRNAs in association with Neurodegenerative Disorders

Curator: Amandeep Kaur

Research over the years has added evidences to the hypothesis of “RNA world” which explains the evolution of DNA and protein from a simple RNA molecule. Our understanding of RNA biology has dramatically changed over the last 50 years and rendered the scientists with the conclusion that apart from coding for protein synthesis, RNA also plays an important role in regulation of gene expression.

Figure: Overall Taxonomy of ncRNAs
Figure: Overall Taxonomy of ncRNAs
https://www.nature.com/articles/s42256-019-0051-2

The universe of non-coding RNAs (ncRNAs) is transcending the margins of preconception and altered the traditional thought that the coding RNAs or messenger RNAs (mRNAs) are more prevalent in our cells. Research on the potential use of ncRNAs in therapeutic relevance increased greatly after the discovery of RNA interference (RNAi) and provided important insights into our further understanding of etiology of complex disorders.

Figure: Atomic Structure of Non-coding RNA
https://en.wikipedia.org/wiki/Non-coding_RNA

Latest research on neurodegenerative disorders has shown the perturbed expression of ncRNAs which provides the functional association between neurodegeneration and ncRNAs dysfunction. Due to the diversity of functions and abundance of ncRNAs, they are classified into Housekeeping RNAs and Regulatory ncRNAs.

The best known classes of ncRNAs are the microRNAs (miRNAs) which are extensively studied and are of research focus. miRNAs are present in both intronic and exonic regions of matured RNA (mRNA) and are crucial for development of CNS. The reduction of Dicer-1, a miRNA biogenesis-related protein affects neural development and the elimination of Dicer in specifically dopaminergic neurons causes progressive degeneration of these neuronal cells in striatum of mice.

A new class of regulatory ncRNAs, tRNAs-derived fragments (tRFs) is superabundantly present in brain cells. tRFs are considered as risk factors in conditions of neural degeneration because of accumulation with aging. tRFs have heterogenous functions with regulation of gene expression at multiple layers including regulation of mRNA processing and translation, inducing the activity of silencing of target genes, controlling cell growth and differentiation processes.

The existence of long non-coding RNAs (lncRNAs) was comfirmed by the ENCODE project. Numerous studies reported that approximately 40% of lncRNAs are involved in gene expression, imprinting and pluripotency regulation in the CNS. lncRNA H19 is of paramount significance in neural viability and contribute in epilepsy condition by activating glial cells. Other lncRNAs are highly bountiful in neurons including Evf2 and MALAT1 which play important function in regulating neural differentiation and synapse formation and development of dendritic cells respectively.

Recently, a review article in Nature mentioned about the complex mechanisms of ncRNAs contributing to neurodegenerative conditions. The ncRNA-mediated mechanisms of regulation are as follows:

  • Epigenetic regulation: Various lncRNAs such as BDNF-AS, TUG1, MEG3, NEAT1 and TUNA are differentially expressed in brain tissue and act as epigenetic regulators.
  • RNAi: RNA interference includes post-transcriptional repression by small-interfering RNAs (siRNAs) and binding of miRNAs to target genes. In a wide spectrum of neurodegenerative diseases such as Alzheimer’s disease, Parkinson disease, Huntington’s disease, Amyotrophic lateral sclerosis, Fragile X syndrome, Frontotemporal dementia, and Spinocerebellar ataxia, have shown perturbed expression of miRNA.
  • Alternative splicing: Variation in splicing of transcripts of ncRNAs has shown adverse affects in neuropathology of degenerative diseases.
  • mRNA stability: The stability of mRNA may be affected by RNA-RNA duplex formation which leads to the degradation of sense mRNA or blocking the access to proteins involved in RNA turnover and modify the progression of neurodegenerative disorders.
  • Translational regulation: Numerous ncRNAs including BC200 directly control the translational process of transcripts of mRNAs and effect human brain of Alzheimer’s disease.
  • Molecular decoys: Non-coding RNAs (ncRNAs) dilute the expression of other RNAs by molecular trapping, also known as competing endogenous RNAs (ceRNAs) which hinder the normal functioning of RNAs. The ceRNAs proportion must be equivalent to the number of target miRNAs that can be sequestered by each ncRNAs in order to induce consequential de-repression of the target molecules.
Table: ncRNAs and related processes involved in neurodegenerative disorders
https://www.nature.com/articles/nrn.2017.90

The unknown functions of numerous annotated ncRNAs may explain the underlying complexity in neurodegenerative disorders. The profiling of ncRNAs of patients suffering from neurodevelopmental and neurodegenerative conditions are required to outline the changes in ncRNAs and their role in specific regions of brain and cells. Analysis of Large-scale gene expression and functional studies of ncRNAs may contribute to our understanding of these diseases and their remarkable connections. Therefore, targeting ncRNAs may provide effective therapeutic perspective for the treatment of neurodegenerative diseases.

References https://www.nature.com/scitable/topicpage/rna-functions-352/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6035743/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7695195/ https://link.springer.com/article/10.1007/s13670-012-0023-4 https://www.nature.com/articles/nrn.2017.90

 

Other related articles were published in this Open Access Online Scientific Journal, including the following:

RNA in synthetic biology

Curator: Larry H. Bernstein, MD, FCAP

https://pharmaceuticalintelligence.com/2016/03/26/rna-in-synthetic-biology/

mRNA Data Survival Analysis

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

https://pharmaceuticalintelligence.com/2016/06/18/mrna-data-survival-analysis/

Recent progress in neurodegenerative diseases and gliomas

Curator: Larry H. Bernstein, MD, FCAP

https://pharmaceuticalintelligence.com/2016/05/28/recent-progress-in-neurodegenerative-diseases-and-gliomas/

Genomic Promise for Neurodegenerative Diseases, Dementias, Autism Spectrum, Schizophrenia, and Serious Depression

Reporter and writer: Larry H Bernstein, MD, FCAP

https://pharmaceuticalintelligence.com/2013/02/19/genomic-promise-for-neurodegenerative-diseases-dementias-autism-spectrum-schizophrenia-and-serious-depression/

Read Full Post »


Reporter: Adina Hazan, PhD

Elizabeth Unger from the Tian group at UC Davis, Jacob Keller from the Looger lab from HHMI, Michael Altermatt from the Gradinaru group at California Institute of Technology, and colleagues did just this, by redesigned the binding pocket of periplasmic binding proteins (PBPs) using artificial intelligence, such that it became a fluorescent sensor specific for serotonin. Not only this, the group showed that it could express and use this molecule to detect serotonin on the cell, tissue, and whole animal level.

By starting with a microbial PBP and early version of an acetyl choline sensor (iAChSnFR), the scientists used machine learning and modeling to redesign the binding site to exhibit a higher affinity and specificity to serotonin. After three repeats of mutagenesis, modeling, and library readouts, they produced iSeroSnFR. This version harbors 19 mutations compared to iAChSnFR0.6 and a Kd of 310 µM. This results in an increase in fluorescence in HEK293T cells expressing the serotonin receptor of 800%. Of over 40 neurotransmitters, amino acids, and small molecules screened, only two endogenous molecules evoked some fluorescence, but at significantly higher concentrations.

To acutely test the ability of the sensor to detect rapid changes of serotonin in the environment, the researchers used caged serotonin, a technique in which the serotonin is rapidly released into the environment with light pulses, and showed that iSeroSnFR accurately and robustly produced a signal with each flash of light. With this tool, it was then possible to move to ex-vivo mouse brain slices and detect endogenous serotonin release patterns across the brain. Three weeks after targeted injection of iSeroSnFR to specifically deliver the receptor into the prefrontal cortex and dorsal striatum, strong fluorescent signal could be detected during perfusion of serotonin or electrical stimulation.

Most significantly, this molecule was also shown to be detected in freely moving mice, a tool which could offer critical insight into the acute role of serotonin regulation during important functions such as mood and alertness. Through optical fiber placements in the basolateral amygdala and prefrontal cortex, the team measured dynamic and real-time changes in serotonin release in fear-trained mice, social interactions, and sleep wake cycles. For example, while both areas of the brain have been established as relevant to the fear response, they reliably tracked that the PFC response was immediate, while the BSA displayed a delayed response. This additional temporal resolution of neuromodulation may have important implications in neurotransmitter pharmacology of the central nervous system.

This study provided the scientific community with several insights and tools. The serotonin sensor itself will be a critical tool in the study of the central nervous system and possibly beyond. Additionally, an AI approach to mutagenesis in order to redesign a binding pocket of a receptor opens new avenues to the development of pharmacological tools and may lead to many new designs in therapeutics and research.

SOURCE:

Read Full Post »


Connecting the Immune Response to Amyloid-β Aggregation in Alzheimer’s Disease via IFITM3

Reporter : Irina Robu, PhD

Alzheimer’s disease is a complex condition and it begins with slow aggregation of amyloid-β deposits over the course of years. This produces a mild cognitive impairment and a state of chronic inflammation enough to trigger harmful aggregation of the altered tau protein. Clearing amyloid-β from the brain hasn’t produced telling benefits to patients suggesting that it is not the key process in the development of the condition.

Recent research indicates that beta-amyloid has antiviral and antimicrobial properties, indicating a possible link between the immune response against infections and development of Alzheimer’s disease. Scientists have discovered evidence that protein interferon-induced transmembrane protein 3 (IFITM3) is involved in immune response to pathogens and play a key role in the accumulation of beta amyloid in plaques. IFITM3 is able to alter the activity of gamma-secretase enzyme, which breaks down the precursor proteins into fragments of beta-amyloid that make up plaques. 

Yet it was determined that the production of IFITM3 starts in reply to activation of the immune system by invading viruses and bacteria. Indeed, researchers found that the level of IFITM3 in human brain samples correlated with levels of certain viral infections as well as with gamma-secretase activity and beta-amyloid production. Age is the number one risk factor for Alzheimer’s and the levels of both inflammatory markers and IFITM3 increased with advancing age in mice.

Innate immunity is also correlated with Alzheimer’s disease1, but the influence of immune activation on the production of amyloid beta is unknown. They were able to identify IFITM3 as γ-secretase modulatory protein, and establish a mechanism by which inflammation affects the generation of amyloid-β.

According to the current research, inflammatory cytokines induce the expression of IFITM3 in neurons and astrocytes, which binds to γ-secretase and upregulates its activity, thereby increasing the production of amyloid-β. The expression of IFITM3 is increased with ageing and in mouse models that express Alzheimer’s disease genes. IFITM3 protein is upregulated in tissue samples from a subset of patients with late-onset Alzheimer’s disease that exhibit higher γ-secretase activity. The amount of IFITM3 in the γ-secretase complex has a strong and positive correlation with γ-secretase activity in samples from patients with late-onset Alzheimer’s disease. These conclusions disclose a mechanism in which γ-secretase is controlled by neuroinflammation via IFITM3 and the risk of Alzheimer’s disease is thus amplified

SOURCE

https://www.nature.com/articles/s41586-020-2681-2

Read Full Post »


Lesson 7 of Cell Signaling 7 Motility: Tubulin and Tutorial Quizes for #TUBiol3373

Stephen J. Williams, Ph.D.

This lesson (lesson 7) will discuss the last type of cytoskeletal structure: microtubules and tubulin.  In addition I want to go over the last quiz answers and also introduce some new poll quizes.

I had given the lecture 7 over Canvas and each of you can download and go over the lecture but I will highlight a few slides in the lecture.

Let’s first review:

Remember that microtubules are the largest of the three cytoskeletal structures:

actin microfilaments < intermediate filaments < microtubules

This is very important to understand as the microtubules, as shown later, shuttle organelles and cellular structures like synaptic vesicles, as well as forming the centrisome and spindle fibers of mitosis.

 

 

 

 

 

 

 

 

 

 

 

 

 

Now remember the quiz question from last time

Remember that actin monomers (the G actin binds ATP)  while tubulin, the protein which makes up the microtubules binds GTP {although it is a little more complex than that as the following diagram shows}

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

See how the growth at the plus end is dependent on tubulin heterodimer GTP while when GDP is only bound to tubulin (both forms) you get a destabilization of the plus end and removal of tubulin dimers (catastrophe) if there is no source of tubulin GTP dimers (alpha tubulin GTP with beta tubulin GTP).

 

 

 

 

Also remember that like actin microfilaments you can have treadmilling (the plus end  continues growing while minus end undergoes catasrophe).  The VIDEO below describes these processes:

 

 

 

Certain SNPs and mutants of tubulin are found and can result in drastic phenotypic changes in microtubule stability and structure. Below is an article where a mutation in tubulin can result in microtubule catastrophe or destabilization of microtubule structures.

 

From: A mutation uncouples the tubulin conformational and GTPase cycles, revealing allosteric control of microtubule dynamics;, E.A. Geyer et al..; elife 2015;4:e10113

Abstract

Microtubule dynamic instability depends on the GTPase activity of the polymerizing αβ-tubulin subunits, which cycle through at least three distinct conformations as they move into and out of microtubules. How this conformational cycle contributes to microtubule growing, shrinking, and switching remains unknown. Here, we report that a buried mutation in αβ-tubulin yields microtubules with dramatically reduced shrinking rate and catastrophe frequency. The mutation causes these effects by suppressing a conformational change that normally occurs in response to GTP hydrolysis in the lattice, without detectably changing the conformation of unpolymerized αβ-tubulin. Thus, the mutation weakens the coupling between the conformational and GTPase cycles of αβ-tubulin. By showing that the mutation predominantly affects post-GTPase conformational and dynamic properties of microtubules, our data reveal that the strength of the allosteric response to GDP in the lattice dictates the frequency of catastrophe and the severity of rapid shrinking.

https://doi.org/10.7554/eLife.10113.001

 

Remember the term allosterism: change in the affinity for binding of a ligand or substrate that is caused by the binding of another ligand away from the active site (for example like 2,3 DPG effect on oxygen binding to hemoglobin

 

Cellular transport of organelles and vesicles: a function of microtubules

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Now the above figure (figure 9 in your Powerpoint) shows the movement of organelles and vesicles in two different types of cells along microtubules.

Note the magenta arrow which goes from the nucleus toward the plus end of the microtubule (at cell membrane) is referred to as anterograde transport and is movement away from center of cell to the periphery.  Retrograde transport is movement of organelles and vesicles from periphery of cell to the center of the cell.

Note that kinesin is involved in anterograde transport while dyenin is involved in retrograde transport

Also refer to the Wiki page which shows a nice cartoon of this walking down a microtubule on the right hand side of the page

https://en.wikipedia.org/wiki/Axonal_transport

 

 

 

 

 

 

 

Cilia; a cellular structure of microtubules (we will talk about cilia later)

for more information on structure of Cillia please see https://www.ncbi.nlm.nih.gov/books/NBK21698/

This is from a posting by Dr. Larry Bernstein of Yale University at https://pharmaceuticalintelligence.com/2015/11/04/cilia-and-tubulin/

 

RESEARCHERS VIDEO AND MEASURE TUBULIN TRANSPORT IN CILIA FOR THE FIRST TIME.

http://health-innovations.org/2015/01/27/researchers-image-and-measure-tubulin-transport-in-cilia/

 

 

https://michellepetersen76.files.wordpress.com/2015/01/uga-researchers-image-and-measure-tubulin-transport-in-cilia-healthinnovations1.png

 

Defective cilia can lead to a host of diseases and conditions in the human body, from rare, inherited bone malformations to blindness, male infertility, kidney disease and obesity. It is known that these tiny cell organelles become deformed and cause these diseases because of a problem related to their assembly, which requires the translocation of vast quantities of the vital cell protein tubulin. What they didn’t know was how tubulin and another cell organelle known as flagella fit into the process.

Now, a new study from University of Georgia shows the mechanism behind tubulin transport and its assembly into cilia, including the first video imagery of the process. The study was published in the Journal of Cell Biology.

Cilia are found throughout the body, so defects in cilia formation affect cells that line airways, brain ventricles or the reproductive track.  One of the main causes of male infertility is the cilia won’t function properly.

The team used total internal reflection fluorescence microscopy to analyze moving protein particles inside the cilia of Chlamydomonas reinhardtii, a green alga widely used as a model for cilia analysis.

The team exploited the natural behaviour of the organism, which is to attach by its cilia to a smooth surface, such as a microscope glass cover. This positions the cilia within the 200-nanometer reach of the total internal reflection fluorescence microscope allowing for the imaging of individual proteins as they move inside the cilia.  A video explaining the process was published along with the study.

Tubulin is transported by this process called intraflagellar transport, or IFT.  Though it has long been suspected in the field and there was indirect evidence to support the theory, this is the first time it has been shown directly, through live imaging, that IFT does function as a tubulin pump.  The team observed that about 400,000 tubulin dimers need to be transported within 60 minutes to assemble a single cilium. Being able to see tubulin moving into cilia allowed for first insights into how this transport is regulated to make sure cilia will have the correct size.

The new findings are expected to have wide implications for a variety of diseases and conditions related to cilia defects in the body.  The team state that they are on the very basic side of this research.  But because more and more diseases are being connected to cilia-related conditions, including obesity and even diabetes, the number of people working on cilia has greatly expanded over the last few years.

 

So here are the answer to last weeks polls

  1. Actin filaments are the SMALLEST of the cytoskeletal structures.  As shown in this lecture it is tubulin that binds GTP.  Actin binds ATP.
  2.  ARP2/3 or actin related proteins 2 and 3 are nucleating proteins that assist in initiating growth of branched chain micofiliment networks.  Formins are associated with unbranched actin formations.
  3.  The answer is GAPs or GTPase activating proteins.  Remember RAS in active state when GTP is bound and when you hydrolyze the GTP to GDP Ras is inactive state

 

 

 

 

 

4.  Okay so I did a type here but the best answer was acetylcholinesterase (AchE) degrading acetylcholine.  Acetylcholinesterase degrades the neurotransmitter acetylcholine into choline and acetate not as I accidentally put into acetylCoA.  The freed choline can then be taken back up into the presynaptic neuron and then, with a new acetyl group (with Coenzyme A) will form acetylcholine.

 

Synthesis of the neurotransmitter acetylcholine

 

 

 

The neuromuscular junction

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Thanks to all who took the quiz.  Remember it is for your benefit.

 

 

 

 

Read Full Post »


Reporter and Curator: Dr. Sudipta Saha, Ph.D.

 

Parkinson’s Disease (PD), characterized by both motor and non-motor system pathology, is a common neurodegenerative disorder affecting about 1% of the population over age 60. Its prevalence presents an increasing social burden as the population ages. Since its introduction in the 1960’s, dopamine (DA)-replacement therapy (e.g., L-DOPA) has remained the gold standard treatment. While improving PD patients’ quality of life, the effects of treatment fade with disease progression and prolonged usage of these medications often (>80%) results in side effects including dyskinesias and motor fluctuations. Since the selective degeneration of A9 mDA neurons (mDANs) in the substantia nigra (SN) is a key pathological feature of the disease and is directly associated with the cardinal motor symptoms, dopaminergic cell transplantation has been proposed as a therapeutic strategy.

 

Researchers showed that mammalian fibroblasts can be converted into embryonic stem cell (ESC)-like induced pluripotent stem cells (iPSCs) by introducing four transcription factors i.e., Oct4, Sox2, Klf4, and c-Myc. This was then accomplished with human somatic cells, reprogramming them into human iPSCs (hiPSCs), offering the possibility of generating patient-specific stem cells. There are several major barriers to implementation of hiPSC-based cell therapy for PD. First, probably due to the limited understanding of the reprogramming process, wide variability exists between the differentiation potential of individual hiPSC lines. Second, the safety of hiPSC-based cell therapy has yet to be fully established. In particular, since any hiPSCs that remain undifferentiated or bear sub-clonal tumorigenic mutations have neoplastic potential, it is critical to eliminate completely such cells from a therapeutic product.

 

In the present study the researchers established human induced pluripotent stem cell (hiPSC)-based autologous cell therapy. Researchers reported a platform of core techniques for the production of mDA progenitors as a safe and effective therapeutic product. First, by combining metabolism-regulating microRNAs with reprogramming factors, a method was developed to more efficiently generate clinical grade iPSCs, as evidenced by genomic integrity and unbiased pluripotent potential. Second, a “spotting”-based in vitro differentiation methodology was established to generate functional and healthy mDA cells in a scalable manner. Third, a chemical method was developed that safely eliminates undifferentiated cells from the final product. Dopaminergic cells thus produced can express high levels of characteristic mDA markers, produce and secrete dopamine, and exhibit electrophysiological features typical of mDA cells. Transplantation of these cells into rodent models of PD robustly restored motor dysfunction and reinnervated host brain, while showing no evidence of tumor formation or redistribution of the implanted cells.

 

Together these results supported the promise of these techniques to provide clinically applicable personalized autologous cell therapy for PD. It was recognized by researchers that this methodology is likely to be more costly in dollars and manpower than techniques using off-the-shelf methods and allogenic cell lines. Nevertheless, the cost for autologous cell therapy may be expected to decrease steadily with technological refinement and automation. Given the significant advantages inherent in a cell source free of ethical concerns and with the potential to obviate the need for immunosuppression, with its attendant costs and dangers, it was proposed that this platform is suitable for the successful implementation of human personalized autologous cell therapy for PD.

 

References:

 

https://www.jci.org/articles/view/130767/pdf?elqTrackId=2fd7d0edee744f9cb6d70a686d7b273b

 

https://www.ncbi.nlm.nih.gov/pubmed/31714896

 

https://www.ncbi.nlm.nih.gov/pubmed/23666606

 

https://www.ncbi.nlm.nih.gov/pubmed/27343168

 

https://www.ncbi.nlm.nih.gov/pubmed/21495962

 

https://www.ncbi.nlm.nih.gov/pubmed/28083784

 

https://www.ncbi.nlm.nih.gov/pubmed/20336395

 

https://www.ncbi.nlm.nih.gov/pubmed/28585381

 

Read Full Post »


Contributions to Neuronal Systems by University Professors Eve Marder and Irv Epstein at Brandeis University

Reporter: Aviva Lev-Ari, PhD, RN

Oscillators: Chemicals, Neurons and People: A Celebration of Eve Marder, Irving Epstein and the Volen Center for Complex Systems
Sunday, Nov. 17, 2019, 1 – 5:30 p.m.
Location Schwartz
Room Auditorium
Event Sponsor(S) Office of the Provost
Website www.brandeis.edu…

A celebration for new university professors Eve Marder and Irving Epstein, and the 25th anniversary of the Volen Center!

Schedule of Events

  • 1p.m. – Opening remarks: Leslie Griffith, Nancy Lurie Marks Professor of Neuroscience and Director of the Volen National Center for Complex Systems
  • 1:30 p.m. – Panel Discussion: “Oscillators: Chemicals, Neurons and People”
    • Moderator: Gina Turrigiano, Joseph Levitan Professor of Vision Science
    • Panelist: Jorge Golowasch, Professor, Department of Biological Sciences, New Jersey Institute of Technology
    • Panelist: Nancy Kopell, Professor of Mathematics, Boston University
    • Panelist: Horacio Rotstein, Professor of Mathematical Biology & Computational Neuroscience, Department of Biological Sciences, New Jersey Institute of Technology
    • Panelist: Frances Skinner, Senior Scientist, Krembil Research Institute and Professor, Division of Neurology, Department of Medicine and Department of Physiology, University of Toront
  • 2:30 p.m. – Coffee
  • 3 p.m. – Irving Epstein: “How I Wandered into an Oscillatory State”
  • 4 p.m. – Eve Marder: “The Challenges Posed by Neuronal Oscillators that are both Stable and Plastic”
  • 5 p.m. – Closing remarks: Leslie Griffith

 

Eve Marder and Irv Epstein recall the collaborations that started it all

The University Professors will lead a public symposium on Nov. 17

headshots of University Professors Eve Marder, left, and Irv EpsteinPhoto/Mike LovettUniversity professors Eve Marder ’69, Left, and Irving R. Epstein

University Professors Eve Marder ’69 and Irv Epstein will help celebrate the 25th anniversary of the Volen National Center for Complex Systems in a public symposium November 17.

Marder, the Victor and Gwendolyn Beinfield Professor of Neuroscience, and Epstein, the Henry F. Fischbach Professor of Chemistry, were named University Professors last spring in recognition of their pioneering interdisciplinary achievements. At the symposium, they will each deliver a lecture drawing on their collaborative research on oscillators. In the case of Epstein, these are oscillating chemical reactions. In Marder’s case, it is rhythmically active neurons and/or circuits.   

But some 35 years ago, before they were leaders in their fields, Epstein and Marder saw the benefit of sharing ideas. A mutual colleague noticed that the chemical reactions recorded on the chart recorder Epstein was using looked intriguingly similar to the neuronal signals Marder was recording in her research.

“It’s relatively unusual behavior for chemistry, but it’s sort of the essence of what goes on in neuronal systems,” said Epstein, who soon learned some rudiments of neuroscience from Marder and began mathematically modeling groups of neurons. For her part, Marder “got an appreciation for what interacting with theorists could bring, to help her answer the kind of questions she wanted to answer,” said Epstein.

These days, Marder’s research on small neural circuits found in lobsters and crabs is credited with revolutionizing understanding of the fundamental nature of neuronal circuit operation, including how neuromodulators control behavioral outputs and how the stability of circuits is maintained over time. She has won many top prizes in neuroscience, including the Gruber Award in Neuroscience, the Kavli Prize in Neuroscience, and the National Academy of Sciences Neuroscience Prize. In March, she will receive the Carnegie Prize in Mind and Brain Science from Carnegie Mellon University.

Epstein, a Howard Hughes Medical Institute professor, pioneered the field of chemical oscillators. “When we got into the field of oscillating reactions, there were just three that were known, and they were all discovered accidentally,” said Epstein. “We decided that if we really understood these systems, we should be able to design them.”

Although it took him several years and three unsuccessful grant applications to secure funding for his ideas, Epstein and his lab ultimately won funding, and within a few months succeeded in developing their first novel chemical oscillating reaction.

Writ large, Marder and Epstein collaboratively demonstrate that the kinds of phenomena seen in neurons are also found in chemical and physical systems. “What you learn from modeling chemical reactions can help you understand how neurons work, and vice versa,” said Epstein.

“Volen is a place where you get all kinds of collaborations,” said Marder. “One of Brandeis’ strengths is its interactivity; those early days were quite catalytic.”

 

Categories: ResearchScience and Technology

SOURCE

https://www.brandeis.edu/now/2019/november/eve-irv-volen.html

Read Full Post »


Real Time Coverage @BIOConvention #BIO2019: Gene Therapy 2.0: No Longer Science Fiction 1:00-2:15 pm June 3 Philadelphia PA

Reporter: Stephen J. Williams Ph.D. @StephenJWillia2

kkjk

Other Articles on Gene Therapy on this Open Access Journal Include:

Read Full Post »


Lesson 5 Cell Signaling And Motility: Cytoskeleton & Actin: Curations and Articles of reference as supplemental information: #TUBiol3373

Curator: Stephen J. Williams, Ph.D.

Cell motility or migration is an essential cellular process for a variety of biological events. In embryonic development, cells migrate to appropriate locations for the morphogenesis of tissues and organs. Cells need to migrate to heal the wound in repairing damaged tissue. Vascular endothelial cells (ECs) migrate to form new capillaries during angiogenesis. White blood cells migrate to the sites of inflammation to kill bacteria. Cancer cell metastasis involves their migration through the blood vessel wall to invade surrounding tissues.

Please Click on the Following Powerpoint Presentation for Lesson 4 on the Cytoskeleton, Actin, and Filaments

CLICK ON LINK BELOW

cell signaling 5 lesson

This post will be updated with further information when we get into Lesson 6 and complete our discussion on the Cytoskeleton

Please see the following articles on Actin and the Cytoskeleton in Cellular Signaling

Role of Calcium, the Actin Skeleton, and Lipid Structures in Signaling and Cell Motility

This article, constitutes a broad, but not complete review of the emerging discoveries of the critical role of calcium signaling on cell motility and, by extension, embryonic development, cancer metastasis, changes in vascular compliance at the junction between the endothelium and the underlying interstitial layer.  The effect of calcium signaling on the heart in arrhtmogenesis and heart failure will be a third in this series, while the binding of calcium to troponin C in the synchronous contraction of the myocardium had been discussed by Dr. Lev-Ari in Part I.

Universal MOTIFs essential to skeletal muscle, smooth muscle, cardiac syncytial muscle, endothelium, neovascularization, atherosclerosis and hypertension, cell division, embryogenesis, and cancer metastasis. The discussion will be presented in several parts:
1.  Biochemical and signaling cascades in cell motility
2.  Extracellular matrix and cell-ECM adhesions
3.  Actin dynamics in cell-cell adhesion
4.  Effect of intracellular Ca++ action on cell motility
5.  Regulation of the cytoskeleton
6.  Role of thymosin in actin-sequestration
7.  T-lymphocyte signaling and the actin cytoskeleton

 

Identification of Biomarkers that are Related to the Actin Cytoskeleton

In this article the Dr. Larry Bernstein covers two types of biomarker on the function of actin in cytoskeleton mobility in situ.

  • First, is an application in developing the actin or other component, for a biotarget and then, to be able to follow it as

(a) a biomarker either for diagnosis, or

(b) for the potential treatment prediction of disease free survival.

  • Second, is mostly in the context of MI, for which there is an abundance of work to reference, and a substantial body of knowledge about

(a) treatment and long term effects of diet, exercise, and

(b) underlying effects of therapeutic drugs.

Microtubule-Associated Protein Assembled on Polymerized Microtubules

(This article has a great 3D visualization of a microtuble structure as well as description of genetic diseases which result from mutations in tubulin and effects on intracellular trafficking of proteins.

A latticework of tiny tubes called microtubules gives your cells their shape and also acts like a railroad track that essential proteins travel on. But if there is a glitch in the connection between train and track, diseases can occur. In the November 24, 2015 issue of PNAS, Tatyana Polenova, Ph.D., Professor of Chemistry and Biochemistry, and her team at the University of Delaware (UD), together with John C. Williams, Ph.D., Associate Professor at the Beckman Research Institute of City of Hope in Duarte, California, reveal for the first time — atom by atom — the structure of a protein bound to a microtubule. The protein of focus, CAP-Gly, short for “cytoskeleton-associated protein-glycine-rich domains,” is a component of dynactin, which binds with the motor protein dynein to move cargoes of essential proteins along the microtubule tracks. Mutations in CAP-Gly have been linked to such neurological diseases and disorders as Perry syndrome and distal spinal bulbar muscular dystrophy.

 

Read Full Post »

Older Posts »