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Archive for the ‘Competition in regenerative stem cell science’ Category


LIVE 2018 The 21st Gabay Award to LORENZ STUDER, Memorial Sloan Kettering Cancer Center, contributions in stem cell biology and patient-specific, cell-based therapy

REAL TIME Reporter: Aviva Lev-Ari, PhD, RN

AWARD LECTURE

Tue., Oct. 9, 2018
4:00 PM
Shapiro Campus Center Theater
Brandeis University

CURRENT WINNER

lorenzstuder.jpgLORENZ STUDER

MACARTHUR FELLOWS PROGRAM

Lorenz Studer

Stem Cell Biologist | Class of 2015

Pioneering a new method for large-scale generation of dopaminergic neurons that could provide one of the first treatments for Parkinson’s disease and prove the broader feasibility of stem cell–based therapies for other neurological disorders.

https://www.macfound.org/fellows/947/

118 publications on PubMed

https://www.ncbi.nlm.nih.gov/pubmed/?term=LORENZ+STUDER

 

PRESIDING

Dagmar Ringe Professor of Biochemistry, Chemistry and Rosenstiel Basic Medical Sciences Research Center

WELCOME

Lisa Lynch Provost and Maurice B. Hexter Professor of Social and Economic Policy Brandeis University

 

RESPONSE Lorenz Studer, MD Director, Center for Stem Cell Biology Memorial Sloan Kettering Cancer Center Member, Developmental Biology Program Memorial Sloan Kettering Cancer Center

Fully defined protocol for all ectodermal lineage

  • Nervous system: Forebrain, Midbrain, Spinal cord:
  • CNS lineage to PNS Lineage
  • Excitatory cortical neurons
  • cortical interneurons Astrocytes
  • microglia
  • Age-reset disease – late-onset during reprogramming – Is age reversible?
  • Loss of age-related markers
  • iPSC-derived cells yield stage cell upon differentiation
  • In vitro differentiation techniques: 2D Directed Differentiation 3D- Organoids
  • Graded MORPHOGEN SIGNALING
  • DOXYCYLINE: ISHH-ORGANIZER – 5 discrete forebrain regions
  • Building Human brain cells in 2D and in 3D
  • Organized cells –>>>  directed organoids –>> Organized Organoids
  • Parkinson, 1817 – Essay on Shaky Palsy (Niagrostaterial pathway)
  • Genetics and related dysfunction: affecting PD
  • Charckot, 1889
  • PD – new approach following drugs and deep brain stimulation failure in advanced disease: Fetal tissue transplant trials: Fetal Grafting
  • graft-induced dyskinesia
  • Long term, 15 years positive effects
  • Stem-cell-based regenerative therapy could transform PD therapy
  • 1995  Fetal DA neuron grafting for PD in Switzerland
  • 1998 – midbrain stem cell derived DA neuron
  • 200-2003 – Stem cell in brain implantation in WashDC
  • 2011 – Behavioral assays that are restored in mice
  • Optogenetics: manipulating – Light on the brain – control animal’s neurons
  • MOA of Graft function
  • Dopamine neurons – Stratium area of the human brain
  • From bench to bedside – WNT boost enhances EN1 expression
  • Neuron melanin induction
  • Manufacturing and QA testing: GMP – Off the shelf Allogenic Product
  • 1,000 human dose equivalents
  • cryopreserve
  • MSK-DA01 is highly enriched for mDA neuron precursors without detectable hESC Contaminants
  • FDA feedback and final steps to IND – PRE-IND MEETING: 2014, 2016
  • GLP STUDIES:
  • TUMORIGENICITY, BIODISTRIBUTION AND TOXISITY
  • HISTOLOGY OF FINAL PRODUCT
  • CLINICAL TRIAL DESIGN – STEM-PD – MSK and Weill Cornell Medicine
  • HLA expression is absent in edited iPSC with expression of HLA-E to block NK clearance
  • FUTURE: CRISPR
  • ATLaS-PD – assessing the longitudinal Symptoms/signs to moderate of severe stage
  • Development of a new PD therapy from Pluripotent Stem Cells
  • BlueRock Therapeutics – MSK-PD – Start up – $240Million funding
  • Stem cell based dopamine therapy for PD
  • Immunosuppression for 12 months
  • defined levodopa response > 45% improvement
  • Conclusions
  • Cell banks for clinical trials
  • NY state Stem cell science consortia

http://www.brandeis.edu/rosenstiel/images/pdfs/gabbay21program.pdf

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Lesson 9 Cell Signaling:  Curations and Articles of reference as supplemental information for lecture section on WNTs: #TUBiol3373

Stephen J. Wiilliams, Ph.D: Curator

The following contain curations of scientific articles from the site https://pharmaceuticalintelligence.com  intended as additional reference material  to supplement material presented in the lecture.

Wnts are a family of lipid-modified secreted glycoproteins which are involved in:

Normal physiological processes including

A. Development:

– Osteogenesis and adipogenesis (Loss of wnt/β‐catenin signaling causes cell fate shift of preosteoblasts from osteoblasts to adipocytes)

  – embryogenesis including body axis patterning, cell fate specification, cell proliferation and cell migration

B. tissue regeneration in adult tissue

read: Wnt signaling in the intestinal epithelium: from endoderm to cancer

And in pathologic processes such as oncogenesis (refer to Wnt/β-catenin Signaling [7.10]) and to your Powerpoint presentation

 

The curation Wnt/β-catenin Signaling is a comprehensive review of canonical and noncanonical Wnt signaling pathways

 

To review:

 

 

 

 

 

 

 

 

 

 

 

Activating the canonical Wnt pathway frees B-catenin from the degradation complex, resulting in B-catenin translocating to the nucleus and resultant transcription of B-catenin/TCF/LEF target genes.

Fig. 1 Canonical Wnt/FZD signaling pathway. (A) In the absence of Wnt signaling, soluble β-catenin is phosphorylated by a degradation complex consisting of the kinases GSK3β and CK1α and the scaffolding proteins APC and Axin1. Phosphorylated β-catenin is targeted for proteasomal degradation after ubiquitination by the SCF protein complex. In the nucleus and in the absence of β-catenin, TCF/LEF transcription factor activity is repressed by TLE-1; (B) activation of the canonical Wnt/FZD signaling leads to phosphorylation of Dvl/Dsh, which in turn recruits Axin1 and GSK3β adjacent to the plasma membrane, thus preventing the formation of the degradation complex. As a result, β-catenin accumulates in the cytoplasm and translocates into the nucleus, where it promotes the expression of target genes via interaction with TCF/LEF transcription factors and other proteins such as CBP, Bcl9, and Pygo.

NOTE: In the canonical signaling, the Wnt signal is transmitted via the Frizzled/LRP5/6 activated receptor to INACTIVATE the degradation complex thus allowing free B-catenin to act as the ultimate transducer of the signal.

Remember, as we discussed, the most frequent cancer-related mutations of WNT pathway constituents is in APC.

This shows how important the degradation complex is in controlling canonical WNT signaling.

Other cell signaling systems are controlled by protein degradation:

A.  The Forkhead family of transcription factors

Read: Regulation of FoxO protein stability via ubiquitination and proteasome degradation

B. Tumor necrosis factor α/NF κB signaling

Read: NF-κB, the first quarter-century: remarkable progress and outstanding questions

1.            Question: In cell involving G-proteins, the signal can be terminated by desensitization mechanisms.  How is both the canonical and noncanonical Wnt signal eventually terminated/desensitized?

We also discussed the noncanonical Wnt signaling pathway (independent of B-catenin induced transcriptional activity).  Note that the canonical and noncanonical involve different transducers of the signal.

Noncanonical WNT Signaling

Note: In noncanonical signaling the transducer is a G-protein and second messenger system is IP3/DAG/Ca++ and/or kinases such as MAPK, JNK.

Depending on the different combinations of WNT ligands and the receptors, WNT signaling activates several different intracellular pathways  (i.e. canonical versus noncanonical)

 

In addition different Wnt ligands are expressed at different times (temporally) and different cell types in development and in the process of oncogenesis. 

The following paper on Wnt signaling in ovarian oncogenesis shows how certain Wnt ligands are expressed in normal epithelial cells but the Wnt expression pattern changes upon transformation and ovarian oncogenesis. In addition, differential expression of canonical versus noncanonical WNT ligands occur during the process of oncogenesis (for example below the authors describe the noncanonical WNT5a is expressed in normal ovarian  epithelia yet WNT5a expression in ovarian cancer is lower than the underlying normal epithelium. However the canonical WNT10a, overexpressed in ovarian cancer cells, serves as an oncogene, promoting oncogenesis and tumor growth.

Wnt5a Suppresses Epithelial Ovarian Cancer by Promoting Cellular Senescence

Benjamin G. Bitler,1 Jasmine P. Nicodemus,1 Hua Li,1 Qi Cai,2 Hong Wu,3 Xiang Hua,4 Tianyu Li,5 Michael J. Birrer,6Andrew K. Godwin,7 Paul Cairns,8 and Rugang Zhang1,*

A.           Abstract

Epithelial ovarian cancer (EOC) remains the most lethal gynecological malignancy in the US. Thus, there is an urgent need to develop novel therapeutics for this disease. Cellular senescence is an important tumor suppression mechanism that has recently been suggested as a novel mechanism to target for developing cancer therapeutics. Wnt5a is a non-canonical Wnt ligand that plays a context-dependent role in human cancers. Here, we investigate the role of Wnt5a in regulating senescence of EOC cells. We demonstrate that Wnt5a is expressed at significantly lower levels in human EOC cell lines and in primary human EOCs (n = 130) compared with either normal ovarian surface epithelium (n = 31; p = 0.039) or fallopian tube epithelium (n = 28; p < 0.001). Notably, a lower level of Wnt5a expression correlates with tumor stage (p = 0.003) and predicts shorter overall survival in EOC patients (p = 0.003). Significantly, restoration of Wnt5a expression inhibits the proliferation of human EOC cells both in vitro and in vivo in an orthotopic EOC mouse model. Mechanistically, Wnt5a antagonizes canonical Wnt/β-catenin signaling and induces cellular senescence by activating the histone repressor A (HIRA)/promyelocytic leukemia (PML) senescence pathway. In summary, we show that loss of Wnt5a predicts poor outcome in EOC patients and Wnt5a suppresses the growth of EOC cells by triggering cellular senescence. We suggest that strategies to drive senescence in EOC cells by reconstituting Wnt5a signaling may offer an effective new strategy for EOC therapy.

Oncol Lett. 2017 Dec;14(6):6611-6617. doi: 10.3892/ol.2017.7062. Epub 2017 Sep 26.

Clinical significance and biological role of Wnt10a in ovarian cancer. 

Li P1Liu W1Xu Q1Wang C1.

Ovarian cancer is one of the five most malignant types of cancer in females, and the only currently effective therapy is surgical resection combined with chemotherapy. Wnt family member 10A (Wnt10a) has previously been identified to serve an oncogenic function in several tumor types, and was revealed to have clinical significance in renal cell carcinoma; however, there is still only limited information regarding the function of Wnt10a in the carcinogenesis of ovarian cancer. The present study identified increased expression levels of Wnt10a in two cell lines, SKOV3 and A2780, using reverse transcription-polymerase chain reaction. Functional analysis indicated that the viability rate and migratory ability of SKOV3 cells was significantly inhibited following Wnt10a knockdown using short interfering RNA (siRNA) technology. The viability rate of SKOV3 cells decreased by ~60% compared with the control and the migratory ability was only ~30% of that in the control. Furthermore, the expression levels of β-catenin, transcription factor 4, lymphoid enhancer binding factor 1 and cyclin D1 were significantly downregulated in SKOV3 cells treated with Wnt10a-siRNA3 or LGK-974, a specific inhibitor of the canonical Wnt signaling pathway. However, there were no synergistic effects observed between Wnt10a siRNA3 and LGK-974, which indicated that Wnt10a activated the Wnt/β-catenin signaling pathway in SKOV3 cells. In addition, using quantitative PCR, Wnt10a was overexpressed in the tumor tissue samples obtained from 86 patients with ovarian cancer when compared with matching paratumoral tissues. Clinicopathological association analysis revealed that Wnt10a was significantly associated with high-grade (grade III, P=0.031) and late-stage (T4, P=0.008) ovarian cancer. Furthermore, the estimated 5-year survival rate was 18.4% for patients with low Wnt10a expression levels (n=38), whereas for patients with high Wnt10a expression (n=48) the rate was 6.3%. The results of the present study suggested that Wnt10a serves an oncogenic role during the carcinogenesis and progression of ovarian cancer via the Wnt/β-catenin signaling pathway.

Targeting the Wnt Pathway includes curations of articles related to the clinical development of Wnt signaling inhibitors as a therapeutic target in various cancers including hepatocellular carcinoma, colon, breast and potentially ovarian cancer.

 

2.         Question: Given that different Wnt ligands and receptors activate different signaling pathways, AND  WNT ligands  can be deferentially and temporally expressed  in various tumor types and the process of oncogenesis, how would you approach a personalized therapy targeting the WNT signaling pathway?

3.         Question: What are the potential mechanisms of either intrinsic or acquired resistance to Wnt ligand antagonists being developed?

 

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

Targeting the Wnt Pathway [7.11]

Wnt/β-catenin Signaling [7.10]

Cancer Signaling Pathways and Tumor Progression: Images of Biological Processes in the Voice of a Pathologist Cancer Expert

e-Scientific Publishing: The Competitive Advantage of a Powerhouse for Curation of Scientific Findings and Methodology Development for e-Scientific Publishing – LPBI Group, A Case in Point 

Electronic Scientific AGORA: Comment Exchanges by Global Scientists on Articles published in the Open Access Journal @pharmaceuticalintelligence.com – Four Case Studies

 

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Colon cancer and organoids

Larry H. Bernstein, MD, FCAP, Curator

LPBI

 

 

 

Guts and Glory

An open mind and collaborative spirit have taken Hans Clevers on a journey from medicine to developmental biology, gastroenterology, cancer, and stem cells.

By Anna Azvolinsky    http://www.the-scientist.com/?articles.view/articleNo/45580/title/Guts-and-Glory

Ihave had to talk a lot about my science recently and it’s made me think about how science works,” says Hans Clevers. “Scientists are trained to think science is driven by hypotheses, but for [my lab], hypothesis-driven research has never worked. Instead, it has been about trying to be as open-minded as possible—which is not natural for our brains,” adds the Utrecht University molecular genetics professor. “The human mind is such that it tries to prove it’s right, so pursuing a hypothesis can result in disaster. My advice to my own team and others is to not preformulate an answer to a scientific question, but just observe and never be afraid of the unknown. What has worked well for us is to keep an open mind and do the experiments. And find a collaborator if it is outside our niche.”

“One thing I have learned is that hypothesis-driven research tends not to be productive when you are in an unknown territory.”

Clevers entered medical school at Utrecht University in The Netherlands in 1978 while simultaneously pursuing a master’s degree in biology. Drawn to working with people in the clinic, Clevers had a training position in pediatrics lined up after medical school, but then mentors persuaded him to spend an additional year converting the master’s degree to a PhD in immunology. “At the end of that year, looking back, I got more satisfaction from the research than from seeing patients.” Clevers also had an aptitude for benchwork, publishing four papers from his PhD year. “They were all projects I had made up myself. The department didn’t do the kind of research I was doing,” he says. “Now that I look back, it’s surprising that an inexperienced PhD student could come up with a project and publish independently.”

Clevers studied T- and B-cell signaling; he set up assays to visualize calcium ion flux and demonstrated that the ions act as messengers to activate human B cells, signaling through antibodies on the cell surface. “As soon as the experiment worked, I got T cells from the lab next door and did the same experiment. That was my strategy: as soon as something worked, I would apply it elsewhere and didn’t stop just because I was a B-cell biologist and not a T-cell biologist. What I learned then, that I have continued to benefit from, is that a lot of scientists tend to adhere to a niche. They cling to these niches and are not that flexible. You think scientists are, but really most are not.”

Here, Clevers talks about promoting a collaborative spirit in research, the art of doing a pilot experiment, and growing miniature organs in a dish.

Clevers Creates

Re-search? Clevers was born in Eindhoven, in the south of The Netherlands. The town was headquarters to Philips Electronics, where his father worked as a businessman, and his mother took care of Clevers and his three brothers. Clevers did well in school but his passion was sports, especially tennis and field hockey, “a big thing in Holland.” Then in 1975, at age 18, he moved to Utrecht University, where he entered an intensive, biology-focused program. “I knew I wanted to be a biology researcher since I was young. In Dutch, the word for research is ‘onderzoek’ and I knew the English word ‘research’ and had wondered why there was the ‘re’ in the word, because I wanted to search but I didn’t want to do re-search—to find what someone else had already found.”

Opportunity to travel. “I was very disappointed in my biology studies, which were old-fashioned and descriptive,” says Clevers. He thought medicine might be more interesting and enrolled in medical school while still pursuing a master’s degree in biology at Utrecht. For the master’s, Clevers had to do three rotations. He spent a year at the International Laboratory for Research on Animal Diseases (ILRAD) in Nairobi, Kenya, and six months in Bethesda, Maryland, at the National Institutes of Health. “Holland is really small, so everyone travels.” Clevers saw those two rotations more as travel explorations. In Nairobi, he went on safaris and explored the country in Land Rovers borrowed from the institute. While in Maryland in 1980, Clevers—with the consent of his advisor, who thought it was a good idea for him to get a feel for the U.S.—flew to Portland, Oregon, and drove back to Boston with a musician friend along the Canadian border. He met the fiancé of political activist and academic Angela Davis in New York City and even stayed in their empty apartment there.

Life and lab lessons. Back in Holland, Clevers joined Rudolf Eugène Ballieux’s lab at Utrecht University to pursue his PhD, for which he studied immune cell signaling. “I didn’t learn much science from him, but I learned that you always have to create trust and to trust people around you. This became a major theme in my own lab. We don’t distrust journals or reviewers or collaborators. We trust everyone and we share. There will be people who take advantage, but there have only been a few of those. So I learned from Ballieux to give everyone maximum trust and then change this strategy only if they fail that trust. We collaborate easily because we give out everything and we also easily get reagents and tools that we may need. It’s been valuable to me in my career. And it is fun!”

Clevers Concentrates

On a mission. “Once I decided to become a scientist, I knew I needed to train seriously. Up to that point, I was totally self-trained.” From an extensive reading of the immunology literature, Clevers became interested in how T cells recognize antigens, and headed off to spend a postdoc studying the problem in Cox Terhorst’s lab at Dana-Farber Cancer Institute in Boston. “Immunology was young, but it was very exciting and there was a lot to discover. I became a professional scientist there and experienced how tough science is.” In 1988, Clevers cloned and characterized the gene for a component of the T-cell receptor (TCR) called CD3-epsilon, which binds antigen and activates intracellular signaling pathways.

On the fast track in Holland. Clevers returned to Utrecht University in 1989 as a professor of immunology. Within one month of setting up his lab, he had two graduate students and a technician, and the lab had cloned the first T cell–specific transcription factor, which they called TCF-1, in human T cells. When his former thesis advisor retired, Clevers was asked, at age 33, to become head of the immunology department. While the appointment was high-risk for him and for the department, Clevers says, he was chosen because he was good at multitasking and because he got along well with everyone.

Problem-solving strategy. “My strategy in research has always been opportunistic. One thing I have learned is that hypothesis-driven research tends not to be productive when you are in an unknown territory. I think there is an art to doing pilot experiments. So we have always just set up systems in which something happens and then you try and try things until a pattern appears and maybe you formulate a small hypothesis. But as soon as it turns out not to be exactly right, you abandon it. It’s a very open-minded type of research where you question whether what you are seeing is a real phenomenon without spending a year on doing all of the proper controls.”

Trial and error. Clevers’s lab found that while TCF-1 bound to DNA, it did not alter gene expression, despite the researchers’ tinkering with promoter and enhancer assays. “For about five years this was a problem. My first PhD students were leaving and they thought the whole TCF project was a failure,” says Clevers. His lab meanwhile cloned TCF homologs from several model organisms and made many reagents including antibodies against these homologs. To try to figure out the function of TCF-1, the lab performed a two-hybrid screen and identified components of the Wnt signaling pathway as binding partners of TCF-1. “We started to read about Wnt and realized that you study Wnt not in T cells but in frogs and flies, so we rapidly transformed into a developmental biology lab. We showed that we held the key for a major issue in developmental biology, the final protein in the Wnt cascade: TCF-1 binds b-catenin when b-catenin becomes available and activates transcription.” In 1996, Clevers published the mechanism of how the TCF-1 homolog in Xenopus embryos, called XTcf-3, is integrated into the Wnt signaling pathway.

Clevers Catapults

COURTESY OF HANS CLEVERS AND JEROEN HUIJBEN, NYMUS

3DCrypt building and colon cancer.

Clevers next collaborated with Bert Vogelstein’s lab at Johns Hopkins, linking TCF to Wnt signaling in colon cancer. In colon cancer cell lines with mutated forms of the tumor suppressor gene APC, the APC protein can’t rein in b-catenin, which accumulates in the cytoplasm, forms a complex with TCF-4 (later renamed TCF7L2) in the nucleus, and caninitiate colon cancer by changing gene expression. Then, the lab showed that Wnt signaling is necessary for self-renewal of adult stem cells, as mice missing TCF-4 do not have intestinal crypts, the site in the gut where stem cells reside. “This was the first time Wnt was shown to play a role in adults, not just during development, and to be crucial for adult stem cell maintenance,” says Clevers. “Then, when I started thinking about studying the gut, I realized it was by far the best way to study stem cells. And I also realized that almost no one in the world was studying the healthy gut. Almost everyone who researched the gut was studying a disease.” The main advantages of the murine model are rapid cell turnover and the presence of millions of stereotypic crypts throughout the entire intestine.

Against the grain. In 2007, Nick Barker, a senior scientist in the Clevers lab, identified the Wnt target gene Lgr5 as a unique marker of adult stem cells in several epithelial organs, including the intestine, hair follicle, and stomach. In the intestine, the gene codes for a plasma membrane protein on crypt stem cells that enable the intestinal epithelium to self-renew, but can also give rise to adenomas of the gut. Upon making mice with adult stem cell populations tagged with a fluorescent Lgr5-binding marker, the lab helped to overturn assumptions that “stem cells are rare, impossible to find, quiescent, and divide asymmetrically.”

On to organoids. Once the lab could identify adult stem cells within the crypts of the gut, postdoc Toshiro Sato discovered that a single stem cell, in the presence of Matrigel and just three growth factors, could generate a miniature crypt structure—what is now called an organoid. “Toshi is very Japanese and doesn’t always talk much,” says Clevers. “One day I had asked him, while he was at the microscope, if the gut stem cells were growing, and he said, ‘Yes.’ Then I looked under the microscope and saw the beautiful structures and said, ‘Why didn’t you tell me?’ and he said, ‘You didn’t ask.’ For three months he had been growing them!” The lab has since also grown mini-pancreases, -livers, -stomachs, and many other mini-organs.

Tumor Organoids. Clevers showed that organoids can be grown from diseased patients’ samples, a technique that could be used in the future to screen drugs. The lab is also building biobanks of organoidsderived from tumor samples and adjacent normal tissue, which could be especially useful for monitoring responses to chemotherapies. “It’s a similar approach to getting a bacterium cultured to identify which antibiotic to take. The most basic goal is not to give a toxic chemotherapy to a patient who will not respond anyway,” says Clevers. “Tumor organoids grow slower than healthy organoids, which seems counterintuitive, but with cancer cells, often they try to divide and often things go wrong because they don’t have normal numbers of chromosomes and [have] lots of mutations. So, I am not yet convinced that this approach will work for every patient. Sometimes, the tumor organoids may just grow too slowly.”

Selective memory. “When I received the Breakthrough Prize in 2013, I invited everyone who has ever worked with me to Amsterdam, about 100 people, and the lab organized a symposium where many of the researchers gave an account of what they had done in the lab,” says Clevers. “In my experience, my lab has been a straight line from cloning TCF-1 to where we are now. But when you hear them talk it was ‘Hans told me to try this and stop this’ and ‘Half of our knockout mice were never published,’ and I realized that the lab is an endless list of failures,” Clevers recalls. “The one thing we did well is that we would start something and, as soon as it didn’t look very good, we would stop it and try something else. And the few times when we seemed to hit gold, I would regroup my entire lab. We just tried a lot of things, and the 10 percent of what worked, those are the things I remember.”

Greatest Hits

  • Cloned the first T cell–specific transcription factor, TCF-1, and identified homologous genes in model organisms including the fruit fly, frog, and worm
  • Found that transcriptional activation by the abundant β-catenin/TCF-4 [TCF7L2] complex drives cancer initiation in colon cells missing the tumor suppressor protein APC
  • First to extend the role of Wnt signaling from developmental biology to adult stem cells by showing that the two Wnt pathway transcription factors, TCF-1 and TCF-4, are necessary for maintaining the stem cell compartments in the thymus and in the crypt structures of the small intestine, respectively
  • Identified Lgr5 as an adult stem cell marker of many epithelial stem cells including those of the colon, small intestine, hair follicle, and stomach, and found that Lgr5-expressing crypt cells in the small intestine divide constantly and symmetrically, disproving the common belief that stem cell division is asymmetrical and uncommon
  • Established a three-dimensional, stable model, the “organoid,” grown from adult stem cells, to study diseased patients’ tissues from the gut, stomach, liver, and prostate
 Regenerative Medicine Comes of Age   
“Anti-Aging Medicine” Sounds Vaguely Disreputable, So Serious Scientists Prefer to Speak of “Regenerative Medicine”
  • Induced pluripotent stem cells (iPSCs) and genome-editing techniques have facilitated manipulation of living organisms in innumerable ways at the cellular and genetic levels, respectively, and will underpin many aspects of regenerative medicine as it continues to evolve.

    An attitudinal change is also occurring. Experts in regenerative medicine have increasingly begun to embrace the view that comprehensively repairing the damage of aging is a practical and feasible goal.

    A notable proponent of this view is Aubrey de Grey, Ph.D., a biomedical gerontologist who has pioneered an regenerative medicine approach called Strategies for Engineered Negligible Senescence (SENS). He works to “develop, promote, and ensure widespread access to regenerative medicine solutions to the disabilities and diseases of aging” as CSO and co-founder of the SENS Research Foundation. He is also the editor-in-chief of Rejuvenation Research, published by Mary Ann Liebert.

    Dr. de Grey points out that stem cell treatments for age-related conditions such as Parkinson’s are already in clinical trials, and immune therapies to remove molecular waste products in the extracellular space, such as amyloid in Alzheimer’s, have succeeded in such trials. Recently, there has been progress in animal models in removing toxic cells that the body is failing to kill. The most encouraging work is in cancer immunotherapy, which is rapidly advancing after decades in the doldrums.

    Many damage-repair strategies are at an  early stage of research. Although these strategies look promising, they are handicapped by a lack of funding. If that does not change soon, the scientific community is at risk of failing to capitalize on the relevant technological advances.

    Regenerative medicine has moved beyond boutique applications. In degenerative disease, cells lose their function or suffer elimination because they harbor genetic defects. iPSC therapies have the potential to be curative, replacing the defective cells and eliminating symptoms in their entirety. One of the biggest hurdles to commercialization of iPSC therapies is manufacturing.

  • Building Stem Cell Factories

    Cellular Dynamics International (CDI) has been developing clinically compatible induced pluripotent stem cells (iPSCs) and iPSC-derived human retinal pigment epithelial (RPE) cells. CDI’s MyCell Retinal Pigment Epithelial Cells are part of a possible therapy for macular degeneration. They can be grown on bioengineered, nanofibrous scaffolds, and then the RPE cell–enriched scaffolds can be transplanted into patients’ eyes. In this pseudo-colored image, RPE cells are shown growing over the nanofibers. Each cell has thousands of “tongue” and “rod” protrusions that could naturally support rod and cone cells in the eye.

    “Now that an infrastructure is being developed to make unlimited cells for the tools business, new opportunities are being created. These cells can be employed in a therapeutic context, and they can be used to understand the efficacy and safety of drugs,” asserts Chris Parker, executive vice president and CBO, Cellular Dynamics International (CDI). “CDI has the capability to make a lot of cells from a single iPSC line that represents one person (a capability termed scale-up) as well as the capability to do it in parallel for multiple individuals (a capability termed scale-out).”

    Minimally manipulated adult stem cells have progressed relatively quickly to the clinic. In this scenario, cells are taken out of the body, expanded unchanged, then reintroduced. More preclinical rigor applies to potential iPSC therapy. In this case, hematopoietic blood cells are used to make stem cells, which are manufactured into the cell type of interest before reintroduction. Preclinical tests must demonstrate that iPSC-derived cells perform as intended, are safe, and possess little or no off-target activity.

    For example, CDI developed a Parkinsonian model in which iPSC-derived dopaminergic neurons were introduced to primates. The model showed engraftment and enervation, and it appeared to be free of proliferative stem cells.

    • “You will see iPSCs first used in clinical trials as a surrogate to understand efficacy and safety,” notes Mr. Parker. “In an ongoing drug-repurposing trial with GlaxoSmithKline and Harvard University, iPSC-derived motor neurons will be produced from patients with amyotrophic lateral sclerosis and tested in parallel with the drug.” CDI has three cell-therapy programs in their commercialization pipeline focusing on macular degeneration, Parkinson’s disease, and postmyocardial infarction.

    • Keeping an Eye on Aging Eyes

      The California Project to Cure Blindness is evaluating a stem cell–based treatment strategy for age-related macular degeneration. The strategy involves growing retinal pigment epithelium (RPE) cells on a biostable, synthetic scaffold, then implanting the RPE cell–enriched scaffold to replace RPE cells that are dying or dysfunctional. One of the project’s directors, Dennis Clegg, Ph.D., a researcher at the University of California, Santa Barbara, provided this image, which shows stem cell–derived RPE cells. Cell borders are green, and nuclei are red.

      The eye has multiple advantages over other organ systems for regenerative medicine. Advanced surgical methods can access the back of the eye, noninvasive imaging methods can follow the transplanted cells, good outcome parameters exist, and relatively few cells are needed.

      These advantages have attracted many groups to tackle ocular disease, in particular age-related macular degeneration, the leading cause of blindness in the elderly in the United States. Most cases of age-related macular degeneration are thought to be due to the death or dysfunction of cells in the retinal pigment epithelium (RPE). RPE cells are crucial support cells for the rods, cones, and photoreceptors. When RPE cells stop working or die, the photoreceptors die and a vision deficit results.

      A regenerated and restored RPE might prevent the irreversible loss of photoreceptors, possibly via the the transplantation of functionally polarized RPE monolayers derived from human embryonic stem cells. This approach is being explored by the California Project to Cure Blindness, a collaborative effort involving the University of Southern California (USC), the University of California, Santa Barbara (UCSB), the California Institute of Technology, City of Hope, and Regenerative Patch Technologies.

      The project, which is funded by the California Institute of Regenerative Medicine (CIRM), started in 2010, and an IND was filed early 2015. Clinical trial recruitment has begun.

      One of the project’s leaders is Dennis Clegg, Ph.D., Wilcox Family Chair in BioMedicine, UCSB. His laboratory developed the protocol to turn undifferentiated H9 embryonic stem cells into a homogenous population of RPE cells.

      “These are not easy experiments,” remarks Dr. Clegg. “Figuring out the biology and how to make the cell of interest is a challenge that everyone in regenerative medicine faces. About 100,000 RPE cells will be grown as a sheet on a 3 × 5 mm biostable, synthetic scaffold, and then implanted in the patients to replace the cells that are dying or dysfunctional. The idea is to preserve the photoreceptors and to halt disease progression.”

      Moving therapies such as this RPE treatment from concept to clinic is a huge team effort and requires various kinds of expertise. Besides benefitting from Dr. Clegg’s contribution, the RPE project incorporates the work of Mark Humayun, M.D., Ph.D., co-director of the USC Eye Institute and director of the USC Institute for Biomedical Therapeutics and recipient of the National Medal of Technology and Innovation, and David Hinton, Ph.D., a researcher at USC who has studied how actvated RPE cells can alter the local retinal microenvironment.

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Observing the spleen colonies in mice and proving the existence of stem cells – Till and McCulloch

Larry H. Bernstein, MD, FCAP, Curator

Leaders in Pharmaceutical Innovation

Series E. 2; 7.2

 

Till & McCulloch are Doctors James Till and Ernest McCulloch who, while studying the effect of radiation on the bone marrow of mice at the Ontario Cancer Institute, in Toronto, demonstrated the existence of multipotent stem cells in 1961.

Now recognized as the Fathers of Stem Cell Science, Till & McCulloch exemplified the importance of multidisciplinary collaboration in scientific research and have received many awards for their collaborative and ground-breaking research.

They first published their findings of the discovery of stem cells in the journal Radiation Research.[1][2] In later work, joined by graduate student Andy Becker, they cemented their stem cell theory and published the results in the journal Nature in 1963.[3]

After their pioneering discovery, Till & McCulloch continued to help this new field develop; not only by continuing to expand their research activities, but also by mentoring other young scientists. Together, Till & McCulloch spawned successive generations of scientists who continue to deepen the understanding of how the different types of stem cells work and their application to different diseases and medical conditions—many have also become globally recognized leaders in their field.

Dr. Till’s focus shifted increasingly towards the evaluation of cancer therapies and quality of life issues in the 1980s. He has held a wide range of positions in organizations ranging from the Stem Cell Network to Project Open Source to the Canadian Breast Cancer Foundation, and many others.

Dr. McCulloch continued to expand the depth of work in his field with a heavy emphasis on cellular and molecular mechanisms affecting the growth of malignant blast stem cells from the blood of patients with Acute Myeloblastic Leukemia. Unfortunately, Dr. McCulloch died on January 20, 2011, shortly before the 50th anniversary of the publication of the 1961 paper in Radiation Research.

Lifetime Achievement: Drs. James Till and Ernest McCulloch

http://oicr.on.ca/news/portal-news/lifetime-achievement-drs-james-till-and-ernest-mcculloch

In the early 1960s, two Canadian scientists started a series of experiments involving injection of bone marrow cells into irradiated mice.

Dr. James E. Till, a native of Saskatchewan who completed his PhD in biophysics at Yale, and Dr. Ernest McCulloch, a Toronto-born doctor who completed his research training in England, were working together on research related to leukemia at the Ontario Cancer Institute. Their immediate aim was to investigate a controversial new finding by Colorado scientist Theodore Puck, which seemed to show that normal cells are just as susceptible to radiation as cancer cells. At the time, scientists believed radiation “melted” away cancer cells while leaving normal tissue intact. While there was no doubt that radiation is an effective way to kill cancer cells, Puck’s research suggested scientists must be wrong about the way it acts on cells.

Till and McCulloch’s study proved Puck’s finding was correct. But this wasn’t all that their research proved.

In the mouse experiments, they observed nodules in the animals’ spleens when the bone marrow cells were injected. These nodules appeared in proportion to the number of cells injected, leading the two young scientists to speculate that the nodules – which they termed “spleen colonies” – were arising from a single marrow cell. If this were true, the experiment would be a breakthrough, since scientists had not yet proved that it was possible for cells to act in this fashion.

Till and McCulloch conducted further experiments that proved the cells they were observing were indeed stem cells. The rest, as they say, is history.

Still a groundbreaking field

Stem cell research is often discussed in the media as a new, groundbreaking field, but the idea that certain special cells might be responsible for creating many other types of cell goes back quite a bit further than Till and McCulloch’s experiments in the 1960s. The problem of where cells come from is fundamental to biology; for centuries, or perhaps longer, scientists have searched for the origin of the building blocks of life.

Since early in the 1900s, scientists had suspected that there must be some sort of stem cell in the blood forming system. But stem cells proved extraordinarily tricky to observe.

By observing the spleen colonies in mice and proving the existence of stem cells, Till and McCulloch sparked worldwide interest. Once they had established proof that spleen colonies originate from stem cells, there was solid reason to believe that other cells originate from them too – something that has been confirmed through further research.

Developments in technology, biology and research ethics have recently propelled stem cell research to the forefront of public debates on science. Scientists now know that embryonic stem cells can differentiate into all of the specialized embryonic tissues, while adult organisms’ stem cells and progenitor cells can act as a repair system for the body, replenishing specialized cells and maintaining the normal turnover of regenerative organs, such as blood, skin or intestinal tissues.
In the United States, and to a lesser extent in other countries, controversy has erupted as scientists have proposed to explore using human embryonic stem cells – which, by definition, have to be harvested from human embryos – as treatments for disease.

While they tend to garner fewer headlines, there are also many projects exploring the use of adult stem cells in medicine to regenerate parts of the body affected by disease or injury. Research in this area has become very promising since 2006, when Shinya Yamanaka, a researcher at Kyoto University in Japan, showed that adult somatic cells can be “reprogrammed” to act like embryonic stem cells – opening the possibility of using pluripotent stem cells in medicine without harvesting cells from human embryos. The reprogrammed cells, called induced pluripotent stem cells, are an area of intense research activity. In the few years since Yamanaka’s discovery, researchers have already refined and improved techniques for creating induced pluripotent stem cells.

Remarkable careers

In the decades after their discovery, Till and McCulloch continued their research on stem cells, publishing several groundbreaking papers and eventually developing the framework through which stem cells are currently understood. They later moved on to other projects, with McCulloch focusing on cellular and molecular mechanisms affecting the growth of malignant blast stem cells obtained from the blood of patients with acute myeloblastic leukemia, and Till branching out into a number of other health-related fields including evaluation of cancer therapies, quality of life issues and the ethics of Internet research.

Till and McCulloch have received many honours for their research, including the Albert Lasker Award for Basic Medical Research and the Gairdner International Award, Canada’s major award for biomedical research. Both are University Professors Emeritus at the University of Toronto, Officers of the Order of Canada and members of the Order of Ontario and the Canadian Medical Hall of Fame. Till’s research on the impact of the Internet and advocacy for open access to research publications continues to this day. McCulloch is now retired.

Although Till and McCulloch are no longer working in the stem cell field, there are plenty of Ontario scientists who are. The University of Toronto and Ontario Cancer Institute have retained their early lead, developing programs to harness stem cell research for a wide range of applications in medicine. The province rose to international prominence again in the 1990s when Dr. John Dick, a scientist at the Ontario Cancer Institute, proved the existence of cancer stem cells – a subpopulation of cancer cells that are responsible for the growth and spread of cancer.

In the years since, Dick has established a major hub of cancer stem cell research in Ontario. In 2007 the Ontario Institute for Cancer Research appointed Dick as Director of a new Cancer Stem Cell Program to develop and implement a strategy to further understand cancer stem cells and use the concept as the basis for developing new treatments. The program has already recruited rising stars in the cancer stem cell field and has begun working on its ambitious research plan.

“The truly remarkable thing about Drs. Till and McCulloch is that the stem cell discovery was just one part of two very outstanding careers. They also worked tirelessly behind the scenes as builders, teachers and mentors in the decades when Ontario solidified its presence in cancer research,” says Dr. Bob Phillips, Deputy Director of OICR and a former colleague of Till and McCulloch’s at the Ontario Cancer Institute.

“And the remarkable thing about the discovery itself is that we’re just starting to realize the potential of stem cells for medicine. In the 1960s, scientists recognized that Drs. Till and McCulloch’s discovery was important, but I don’t think anyone could have imagined that more than 45 years down the road their work would still be laying the basis for new ideas, new strategies, even new research institutes built around the concept of stem cells.”

Ernest McCulloch: Cell Biology – Conducted a series of experiments that would eventually result in the first proof of the existence of stem cells, a discovery that would revolutionize our understanding of human biology and disease.

“I learned enough about myself to settle on a career in medicine: I did not like discipline – therefore I wanted to work for myself – to be my own boss.”

On an ordinary Sunday more than half a century ago, so ordinary a day that its exact date would later be forgotten, a young faculty member at the Ontario Cancer Institute in Toronto went to work to perform a routine check on his experimental animals. Many years later, he only remembered that it was a cold day, perhaps in the autumn. Navigating his way through quiet streets, Dr. Ernest McCulloch arrived at the Institute and entered the building. After donning his lab coat, McCulloch went to the animal quarters and checked his experimental mice. McCulloch followed a routine process for obtaining samples of their blood-forming tissues, a process which he had done many times before. His goal, working with his research partner James Till, was to determine if, by irradiating mouse bone marrow cells before transplanting them into irradiated mice, changes might later be found in the kinds of cells responsible for blood formation. It was a routine collection of samples on an ordinary day, noteworthy only because it was a Sunday.

After the samples were processed McCulloch, ever the sharp-eyed observer, noticed the unexpected presence of several small rounded bumps on the spleens of mice that had received bone marrow cells, and he decided to count them. He found that the number of nodules on each spleen was directly related to the number of bone marrow cells the mouse had received.

Suddenly things got very exciting for this unlikely duo of researchers. McCulloch was short, a medical doctor, raised in affluent downtown Toronto, with a penchant for classical literature, cinema and poetry. Till, on the other hand, was tall and athletic, a straight-shooting biophysicist who grew up on the Canadian Prairies and loved the sport of curling.

Although it had long been postulated that a single type of cell—a so-called stem cell— could give rise to multiple different cell types, no definitive evidence proved that they existed. The potential of such a “stem cell”, if discovered, would be dramatic, because its ability to regenerate different human body tissues could be used to treat all sorts of diseases. Following this cold, ordinary yet ultimately incredibly exciting day, McCulloch and Till went on to perform a series of seminal experiments in the 1960s that proved, for the first time, the existence of stem cells detected by their “spleen colony formation” assays.

The initial discovery of a direct relationship between the number of colonies and the number of transplanted cells suggested that single rare cells were able to initiate these colonies, but the suggestion required further validation. They knew that they were onto something very interesting, because they found that the colonies contained a variety of precursors of mature blood cell types—red cells, white cells and platelets—the normal cellular components of blood. These foundational observations were published in the specialty journal “Radiation Research” in 1961 under the un-dramatic title “A Direct Measurement of Radiation Sensitivity of Normal Bone Marrow Cells”. The paper did not use the words ”stem cell”, because Till and McCulloch, being rigorous scientists, required stronger evidence before making such a bold interpretation of their findings. Hence, their paper went unnoticed by the general biology community.

Their next paper, published in Nature in 1963, changed this and really brought Till and McCulloch to the forefront of hematological biology —the study of blood. Till’s PhD student Andy Becker found a way to trace the source of the cells in the spleen colonies to demonstrate that they originated from individual cells (not clusters of cells) in the bone marrow and could generate three types of progenitors required to make blood. The paper, titled “Cytological Demonstration of the Clonal Nature of Spleen Colonies Derived from Transplanted Mouse Marrow Cells”, still did not use the word “stem cell” as this was not the nature of these exacting scientists, who demanded that any degree of doubt be extinguished before making such claims.

McCulloch and Till went on to publish a number of subsequent papers, which have now been cited thousands of times, unequivocally demonstrating the presence of special cells within the bone marrow. They, with colleague Louis Siminovitch, offered the first biological definition of stem cells, which included two key characteristics: 1) self renewal – to be a stem cell, a cell must be able to give rise to new copies of itself; 2) differentiation – stem cells are able to divide and generate more mature cells that, following subsequent divisions, are eventually able to generate the highly specialized and functional cells essential for complex multi-cellular organisms work. An example of this can be seen in the hematopoietic (e.g. blood forming) stem cells they described, with a single undifferentiated stem cell being able to eventually form all the different types of cells that comprise our blood.

After these breakthroughs in the 1960s, the pair continued to work together in the field of experimental hematology for the next two decades.  Although they continued to make more discoveries, it was those first findings that caused a huge impact on biology today by demonstrating the presence of stem cells. The field of stem cell biology has expanded dramatically and is now on the verge of a potential revolution in how we understand health and treat disease.

Born in an affluent neighborhood of Toronto, on Warren Road south of St. Clair Avenue, Ernest “Bun” McCulloch was raised well, with a private school education at Upper Canada College and summers at the cottage in the country. Given the nickname “Bun” by his grandmother, the name stuck with him for his entire life. McCulloch was educated as a medical doctor at the University of Toronto, graduating with an MD in 1948, then going on to the Lister Institute in London, England, where he had his first experience with scientific research.

“Bun” returned to Canada in 1949 where he interned at the Toronto General Hospital, specializing in internal medicine. His medical career began at the Sunnybrook Hospital in Toronto where he became an assistant resident and a research fellow in pathology at the Banting Institute. In 1954, McCulloch joined the University of Toronto as a teacher in the Department of Medicine. His next move, taking on the Head of Hematology in the Biology Division at the Ontario Cancer Institute in 1957, would result in his most famous work. He became part of a team of new promising young cancer researchers in the newly founded Department of Medical Biophysics, McCulloch quickly partnered up with James Till to study the effects of radiation on mouse bone marrow cells. The pair conducted a series of experiments that would eventually result in the first proof of the existence of stem cells, a discovery that would revolutionize our understanding of human biology and disease.

Ernest McCulloch was a man of incredible personality and charm. He was extremely well read and enjoyed discussing a wide variety of poetry, classical literature and theatre with his colleagues. He is known for his long-lasting impact on the Canadian medical research community. A list of the notable scientists mentored by Till and McCulloch is a who’s who of Canadian medical scientists, including (but not limited to): former president of the Canadian Institute for Health Research, Alan Bernstein; the discoverer of the T-cell receptor, Tak Mak, and a world leader in the field of hematopoietic stem cell biology, Connie Eaves.

McCulloch and Till’s work resulted in almost every top honor in science, except for the Noble Prize. Widely expected to be a joint winner of this top prize in science with Jim Till, sadly McCulloch passed away in 2011 preventing him from receiving this distinction. Till and McCulloch’s legacy in Canadian biomedical research cannot be understated, with their foundational work in establishing the presence of stem cells within bone marrow and prolific scientific mentorship. With two recent Nobel prizes, 2007 and 2012, going to stem cell researchers who worked on embryonic stem cells and induced pluripotent stem cells, respectively, it is still expected by many scientists that Till’s seminal experiments on adult stem cells will garner him the Nobel prize in the future.

by Ben Paylor

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Metabolic Genomics and Pharmaceutics, Vol. 1 of BioMed Series D available on Amazon Kindle


Metabolic Genomics and Pharmaceutics, Vol. 1 of BioMed Series D available on Amazon Kindle

Reporter: Stephen S Williams, PhD

 

Leaders in Pharmaceutical Business Intelligence would like to announce the First volume of their BioMedical E-Book Series D:

Metabolic Genomics & Pharmaceutics, Vol. I

SACHS FLYER 2014 Metabolomics SeriesDindividualred-page2

which is now available on Amazon Kindle at

http://www.amazon.com/dp/B012BB0ZF0.

This e-Book is a comprehensive review of recent Original Research on  METABOLOMICS and related opportunities for Targeted Therapy written by Experts, Authors, Writers. This is the first volume of the Series D: e-Books on BioMedicine – Metabolomics, Immunology, Infectious Diseases.  It is written for comprehension at the third year medical student level, or as a reference for licensing board exams, but it is also written for the education of a first time baccalaureate degree reader in the biological sciences.  Hopefully, it can be read with great interest by the undergraduate student who is undecided in the choice of a career. The results of Original Research are gaining value added for the e-Reader by the Methodology of Curation. The e-Book’s articles have been published on the Open Access Online Scientific Journal, since April 2012.  All new articles on this subject, will continue to be incorporated, as published with periodical updates.

We invite e-Readers to write an Article Reviews on Amazon for this e-Book on Amazon.

All forthcoming BioMed e-Book Titles can be viewed at:

https://pharmaceuticalintelligence.com/biomed-e-books/

Leaders in Pharmaceutical Business Intelligence, launched in April 2012 an Open Access Online Scientific Journal is a scientific, medical and business multi expert authoring environment in several domains of  life sciences, pharmaceutical, healthcare & medicine industries. The venture operates as an online scientific intellectual exchange at their website http://pharmaceuticalintelligence.com and for curation and reporting on frontiers in biomedical, biological sciences, healthcare economics, pharmacology, pharmaceuticals & medicine. In addition the venture publishes a Medical E-book Series available on Amazon’s Kindle platform.

Analyzing and sharing the vast and rapidly expanding volume of scientific knowledge has never been so crucial to innovation in the medical field. WE are addressing need of overcoming this scientific information overload by:

  • delivering curation and summary interpretations of latest findings and innovations on an open-access, Web 2.0 platform with future goals of providing primarily concept-driven search in the near future
  • providing a social platform for scientists and clinicians to enter into discussion using social media
  • compiling recent discoveries and issues in yearly-updated Medical E-book Series on Amazon’s mobile Kindle platform

This curation offers better organization and visibility to the critical information useful for the next innovations in academic, clinical, and industrial research by providing these hybrid networks.

Table of Contents for Metabolic Genomics & Pharmaceutics, Vol. I

Chapter 1: Metabolic Pathways

Chapter 2: Lipid Metabolism

Chapter 3: Cell Signaling

Chapter 4: Protein Synthesis and Degradation

Chapter 5: Sub-cellular Structure

Chapter 6: Proteomics

Chapter 7: Metabolomics

Chapter 8:  Impairments in Pathological States: Endocrine Disorders; Stress

                   Hypermetabolism and Cancer

Chapter 9: Genomic Expression in Health and Disease 

 

Summary 

Epilogue

 

 

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Optogenetics: The Promise for development of Biological Alternatives to the Electronic Pacemaker: Pacing and Resynchronizing Heartbeat by Activating Light-sensitive Proteins: ion-channel ChR2, overexpressed in Excitable cells in Heart Muscle Cells to modulate their Electrical Activity

Reporter: Aviva Lev-Ari, PhD, RN

Optogenetics for in vivo cardiac pacing and resynchronization therapies

Nature Biotechnology 33, 750–754 (2015) doi:10.1038/nbt.3268
Received
28 February 2014
Accepted
22 May 2015
Published online
22 June 2015

Abnormalities in the specialized cardiac conduction system may result in slow heart rate or mechanical dyssynchrony. Here we apply optogenetics, widely used to modulate neuronal excitability1, 2, 3, 4, for cardiac pacing and resynchronization. We used adeno-associated virus (AAV) 9 to express the Channelrhodopsin-2 (ChR2) transgene at one or more ventricular sites in rats. This allowed optogenetic pacing of the hearts at different beating frequencies with blue-light illumination both in vivo and in isolated perfused hearts. Optical mapping confirmed that the source of the new pacemaker activity was the site of ChR2 transgene delivery. Notably, diffuse illumination of hearts where the ChR2 transgene was delivered to several ventricular sites resulted in electrical synchronization and significant shortening of ventricular activation times. These findings highlight the unique potential of optogenetics for cardiac pacing and resynchronization therapies.

The study was conducted by Dr. Udi Nussinovitch as part of his PhD work in Professor Gepstein’s laboratory at the Technion. Dr. Nussinovitch is currently an intern at the Department of Internal Medicine at Rambam.

The optogenetic technology employed allowed researchers to selectively activate light-sensitive proteins (such as the ion-channel ChR2, first identified in algae), which were overexpressed in excitable cells (such as nerve or muscle cells), in an attempt to modulate (either augment or suppress) their electrical activity. Optogenetics has become an important tool in brain research and the current study is the first to translate this important innovation to pace and resynchronize the heartbeat.

In the study, conducted in rats, the researchers first directed a beam of blue light at an area in the heart where the light-sensitive genes were delivered. This resulted in effective pacing of the heart at different rates as dictated by the frequency of the blue light flashes applied. Subsequently, a more advanced experiment was conducted, in which various locations in the rat hearts expressing ChR2 were activated simultaneously by light, resulting in improved synchronization of the contractions of the ventricles.

Professor Gepstein stresses that this is a preliminary study, and that “in order to translate the aforementioned approach to the clinical arena, we must overcome some significant hurdles. We must

  • improve the penetration of light through the tissues,
  • ensure continuous expression of the protein in the heart for many years, and
  • develop a unique pacing device that will provide the necessary illumination.

But despite all of this, the results of the study demonstrate the unique potential of optogenetics for both

  • cardiac pacing (as an alternative to electronic pacemakers) and
  • resynchronization (for the treatment of heart failure with ventricular dys-synchrony) therapies.”

SOURCES

Nature Biotechnology 33, 750–754 (2015) doi:10.1038/nbt.3268

http://pard.technion.ac.il/2015/06/22/the-illuminated-heart/

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

All Articles in the Electrophysiology Research Category in the Journal

https://pharmaceuticalintelligence.wordpress.com/wp-admin/edit.php?category_name=electrophysiology

Atrioventricular (AV) Conduction Disease (block): Human Mutations affecting the Voltage Clock

Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2013/12/18/atrioventricular-av-conduction-disease-block-human-mutations-affecting-the-voltage-clock/

Selective Ion Conduction

Larry H Bernstein, MD, FCAP

https://pharmaceuticalintelligence.com/2013/10/07/selective-ion-conduction/

Genetics of Conduction Disease: Atrioventricular (AV) Conduction Disease (block): Gene Mutations – Transcription, Excitability, and Energy Homeostasis

Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2013/04/28/genetics-of-conduction-disease-atrioventricular-av-conduction-disease-block-gene-mutations-transcription-excitability-and-energy-homeostasis/

Obesity associated with reduced posterior LA endocardial voltage and infiltration of contiguous posterior LA muscle by epicardial fat, representing a unique substrate for atrial fibrillation (AF)

Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2015/07/07/obesity-associated-with-reduced-posterior-la-endocardial-voltage-and-infiltration-of-contiguous-posterior-la-muscle-by-epicardial-fat-representing-a-unique-substrate-for-atrial-fibrillation-af/

Diagnostics Industry and Drug Development in the Genomics Era: Mid 80s to Present

Larry H Bernstein, MD, FCAP

https://pharmaceuticalintelligence.com/2014/11/21/diagnostics-industry-and-drug-development-in-the-genomics-era-mid-80s-to-present/

Cardiovascular Biology  – A Bibliography of Research @Technion

Aviva Lev-Ari, PhD, RN

https://pharmaceuticalintelligence.com/2014/05/27/cardiovascular-biology-a-bibliography-of-research-technion/

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

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

https://pharmaceuticalintelligence.com/2014/04/28/summary-of-translational-medicine-cardiovascular-diseases-part-1/

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