Study Helps Unravel the Tangled Origin of ALS

Study Helps Unravel the Tangled Origin of ALS

Thursday, 03 April 2014

By studying nerve cells that originated in patients with a severe neurological disease, a University of Wisconsin-Madison researcher has pinpointed an error in protein formation that could be the root of amyotrophic lateral sclerosis.

In this microscope photo of motor neurons created

in the laboratory of Su-Chun Zhang at the University

of Wisconsin-Madison, green marks the nucleus, and

red marks the nerve fibres. Zhang and co-workers at

the Waisman Center have identified a mis-regulation

of protein in the nucleus as the likely first step in the

pathology of ALS, a fatal neurological disorder that

blocks nerve signals to the muscles, and later causes

motor neurons to die. Credit: Hong Chen and

Su-Chun Zhang, Waisman Center, University of

Wisconsin-Madison.

Also called Lou Gehrig's disease, ALS causes paralysis and death. According to the ALS Association, as many as 30,000 Americans are living with ALS.

After a genetic mutation was discovered in a small group of ALS patients, scientists transferred that gene to animals and began to search for drugs that might treat those animals. But that approach has yet to work, says Su-Chun Zhang, a neuroscientist at the Waisman Center at UW-Madison, who is senior author of the new report, published April 3 in the journal Cell Stem Cell.

Zhang has been using a different approach — studying diseased human cells in lab dishes. Those cells, called motor neurons, direct muscles to contract and are the site of failure in ALS.

About 10 years ago, Zhang was the first in the world to grow motor neurons from human embryonic stem cells. More recently, he updated that approach by transforming skin cells into iPS (induced pluripotent stem) cells that were transformed, in turn, into motor neurons.

IPS cells can be used as "disease models," as they carry many of the same traits as their donor. Zhang says the iPS approach offers a key advantage over the genetic approach, which "can only study the results of a known disease-causing gene. With iPS, you can take a cell from any patient, and grow up motor neurons that have ALS. That offers a new way to look at the basic disease pathology."

In the new report, Zhang, Waisman scientist Hong Chen, and colleagues have pointed a finger at proteins that build a transport structure inside the motor neurons. Called neurofilament, this structure moves chemicals and cellular subunits to the far reaches of the nerve cell. The cargo needing movement includes neurotransmitters, which signal the muscles, and mitochondria, which process energy.

Motor neurons that control foot muscles are about three feet long, so neurotransmitters must be moved a yard from their origin in the cell body to the location where they can signal the muscles, Zhang says. A patient lacking this connection becomes paralyzed; tellingly, the first sign of ALS is often paralysis in the feet and legs.

Scientists have known for some time that in ALS, "tangles" along the nerve's projections, formed of misshapen protein, block the passage along the nerve fibres, eventually causing the nerve fibre to malfunction and die. The core of the new discovery is the source of these tangles: a shortage of one of the three proteins in the neurofilament.

The neurofilament combines structural and functional roles, Zhang says.

"Like the studs, joists and rafters of a house, the neurofilament is the backbone of the cell, but it's constantly changing. These proteins need to be shipped from the cell body, where they are produced, to the most distant part, and then be shipped back for recycling. If the proteins cannot form correctly and be transported easily, they form tangles that cause a cascade of problems."

Finding neurofilament tangles in an autopsy of an ALS patient "will not tell you how they happen, when or why they happen," Zhang says. But with millions of cells — all carrying the human disease — to work with, Zhang's research group discovered the source of the tangles in the protein subunits that compose the neurofilaments.

"Our discovery here is that the disease ALS is caused by mis-regulation of one step in the production of the neurofilament," he says.

Beyond ALS, Zhang says "very similar tangles" appear in Alzheimer's and Parkinson's diseases.

"We got really excited at the idea that when you study ALS, you may be looking at the root of many neurodegenerative disorders."

While working with motor neurons sourced in stem cells from patients, Zhang says he and his colleagues saw "quite an amazing thing.”

“The motor neurons we reprogrammed from patient skin cells were relatively young, and we found that the mis-regulation happens very early, which means it is the most likely cause of this disease. Nobody knew this before, but we think if you can target this early step in pathology, you can potentially rescue the nerve cell."

In the experiment just reported, Zhang found a way to rescue the neural cells living in his lab dishes. When his group "edited" the gene that directs formation of the deficient protein, "suddenly the cells looked normal," Zhang says.

Already, he reports, scientists at the Small Molecule Screening and Synthesis Facility at UW-Madison are looking for a way to rescue diseased motor neurons. These neurons are made by the millions from stem cells using techniques that Zhang has perfected over the years.

Zhang says "libraries" of candidate drugs, each containing a thousand or more compounds, are being tested.

"This is exciting. We can put this into action right away. The basic research is now starting to pay off. With a disease like this, there is no time to waste."

Source: University of Wisconsin-Madison

Contact: Su-Chun Zhang

Reference:

Modeling ALS with iPSCs Reveals that Mutant SOD1 Misregulates Neurofilament Balance in Motor Neurons

Hong Chen, Kun Qian, Zhongwei Du, Jingyuan Cao, Andrew Petersen, Huisheng Liu, Lisle W. Blackbourn, CindyTzu-Ling Huang, Anthony Errigo,Yingnan Yin, Jianfeng Lu, Melvin Ayala, Su-Chun Zhang

Cell Stem Cell, April 3 2014, DOI: http://dx.doi.org/10.1016/j.stem.2014.02.004

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Patient Stem Cells Help Identify Common Problem in ALS

Discovery will lead directly to clinical trials

Thursday, 03 April 2014

Harvard stem cell scientists have discovered that a recently approved medication for epilepsy may possibly be a meaningful treatment for amyotrophic lateral sclerosis (ALS) — Lou Gehrig's disease, a uniformly fatal neurodegenerative disorder. The researchers are now collaborating with Massachusetts General Hospital to design an initial clinical trial testing the safety of the treatment in ALS patients.

Kevin Eggan, a principal faculty member of the

Harvard Stem Cell Institute and Professor in

Harvard's Department of Stem Cell and

Regenerative Biology is credited with first moving

ALS – Lou Gehrig's disease into a laboratory dish

in 2008, paving the way for the study of treatments

using human cells. Credit: B.D. Colen/Harvard

University. 

The investigators all caution that a great deal needs to be done to assure the safety and efficacy of the treatment in ALS patients, before physicians should start offering it.

The work, laid out in two related papers in the April 3 online editions of Cell Stem Cell and Cell Reports, is the long-term fruition of studies by Harvard Stem Cell Institute (HSCI) Principal Faculty member Kevin Eggan, PhD, who, in a 2008 Science paper, first raised the possibility of using ALS patient-derived stem cells to better understand the disease and identify therapeutic targets for new drugs.

Now Eggan and HSCI colleague Clifford Woolf, MD, PhD, have found that the many independent mutations that cause ALS may be linked by their ability to trigger abnormally high activity in motor neurons. Using neurons derived from stem cells made from ALS patient skin cells, the two research teams conducted clinical trials of the anti-epilepsy medication on neurons in laboratory dishes, finding that it reduced the hyper-excitability of the cells.

ALS is a devastating and currently untreatable degradation of motor neurons, the long nerve cells that connect the spinal cord to the muscles of the body. While several potential treatments have looked promising in mice, all proved disappointing in the clinic.

"The big problem in ALS is that there are more than a hundred mutations in dozens of genes that all cause the disease, but almost all of the therapeutics that have gone forward in the clinic have done so for just one of those mutations, SOD1, which almost everyone studies in mice," said Eggan, a professor in Harvard's Department of Stem and Regenerative Biology.

"And so, the key question that we really wanted to address was — are clinical efforts failing because the mouse is taking us on a wild goose chase, or is it simply that people haven't had the opportunity to pre-test whether their ideas are true across lots of forms of ALS?", he continued.

In the Cell Stem Cell study, Eggan and postdoctoral fellow Evangelos Kiskinis, PhD, led an effort to make stem cell lines from two women with ALS who have SOD1 mutations to compare human biology and mouse biology. Using a technology called RNA sequencing to look at how the mutation changes gene expression in these lines, the researchers then traced the changes to their impact on biological pathways.

"We found that the mutation makes changes in the motor neurons, which aren't so different from the changes that you see in the mice," Eggan said.

"I think our paper says that while there are definitely some human-specific biology, the mice weren't totally misleading."

Eggan's lab then created more stem cell-derived motor neurons from patients with another form of ALS, as well as people without the disease, to see what changes occur in ALS cells and if these were present across independent genetic mutations.

The surprising result, reported in the Cell Reports study, was that the motor neurons that possessed ALS mutations had a sporadic increase in motor neuron firing while the healthy neurons were quiet unless stimulated in some way.

The ALS hyper-excitability was further examined by Woolf's team, led by Harvard Medical School neurologist Brian Wainger, MD, PhD. Working with Eggan and Kiskinis collectively, they found a cyclical relationship between the increased neuron activity and abnormal protein folding. In the two papers, they describe how the over-excitable ALS neurons generate more abnormally folded proteins, further increasing their excitability. The strain of this cycle seems to put the neurons in a vulnerable state where they are more likely to die.

"The convergence on a single mechanism offered a very attractive place to intervene therapeutically," said Woolf, a Harvard Medical School professor in neurology and neurobiology at Boston Children's Hospital, who also co-leads HSCI's Nervous System Diseases Program.

"It looked like there's a deficit in potassium channels in the ALS motor neurons and that led us to then test whether drugs that open the potassium channels may reduce this hyper-excitability — and indeed that's exactly what we found," he said.

"We found that retigabine, which has recently been approved as an anticonvulsive, normalized this activity; so now we can formally go from the dish to the patient and actually explore whether the drug might have any beneficial effect."

Massachusetts General Hospital neurologist Merit Cudkowicz, MD, with Wainger, will be running the clinical trials, which will first test for side effects when giving the drug to ALS patients. The researchers caution against calling this work a breakthrough or having doctors prescribe this drug to patients immediately. Clinical trials are necessary to determine whether there are any unusual interactions between the drug and having ALS, as having a particular disease can make someone more sensitive to certain types of drugs.

"The whole intact nervous system is more complicated than the cells that we have in the dish at the moment," Eggan said.

"And now the next step is to say whether or not the drug will be helpful in that context, and it's too early to say for sure."

The scientists credit emerging technologies and the unique collaboration between a stem cell lab and a neuron physiology lab as an essential part of making this research clinically relevant for ALS patients.

"I think it's the beginning of a complete change in the way we do medicine for serious diseases like this," Woolf said.

"In a traditional clinical trial, you give the patient the placebo or an active ingredient to see the effects they have and it's over. Here we can take the same stem cell lines and have an infinite capacity to do clinical trials in a dish."

Source: Harvard University 

Contact: B.D. Colen

References:

Intrinsic membrane hyperexcitability of amyotrophic lateral sclerosis patient-derived motor neurons 

Brian J. Wainger, Evangelos Kiskinis, Cassidy Mellin, Ole Wiskow, Steve S.W. Han, Jackson Sandoe, Numa P. Perez, Luis A. Williams, Seungkyu Lee, Gabriella Boulting, James D. Berry, Robert H. Brown Jr., Merit E. Cudkowicz, Bruce P. Bean, Kevin Eggan, Clifford J. Woolf

Cell Reports, April 24, 2014 [published early online April 3, 2014]

Pathways disrupted in human ALS motor neurons identified through genetic correction of mutant SOD1 

Cell Stem Cell, June 5, 2014 [published early online April 3, 2014]

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A New Way to Make Muscle Cells from Human Stem Cells

A New Way to Make Muscle Cells from Human Stem Cells

Friday, 21 March 2014

Muscle cells are stained green in this micrograph

of cells grown from embryonic stem cells in the

lab of Masatoshi Suzuki at the University of

Wisconsin–Madison. Cell nuclei are stained blue;

the muscle fibres contain multiple nuclei. Nuclei

outside the green fibres are from non-muscle cells.

Suzuki has developed a new method of growing

stem cells into muscle cells that could be more

suitable for treating disease. Suzuki hopes to

experiment next with animals that model muscular

dystrophy and amyotrophic lateral sclerosis.

Credit: Masatoshi Suzuki. 

As stem cells continue their gradual transition from the lab to the clinic, a research group at the University of Wisconsin-Madison has discovered a new way to make large concentrations of skeletal muscle cells and muscle progenitors from human stem cells.

The new method, described in the journal Stem Cells Translational Medicine, could be used to generate large numbers of muscle cells and muscle progenitors directly from human pluripotent stem cells. These stem cells, such as embryonic (ES) or induced pluripotent stem (iPS) cells, can be made into virtually any adult cell in the body.

Adapting a method previously used to make brain cells, Masatoshi Suzuki, an assistant professor of comparative biosciences in the School of Veterinary Medicine, has directed those universal stem cells to become both adult muscle cells and muscle progenitors.

Importantly, the new technique grows the pluripotent stem cells as floating spheres in high concentrations of two growth factors, fibroblast growth factor-2 and epidermal growth factor. These growth factors "urge" the stem cells to become muscle cells.

"Researchers have been looking for an easy way to efficiently differentiate stem cells into muscle cells that would be allowable in the clinic," says Suzuki. The novelty of this technique is that it generates a larger number of muscle stem cells without using genetic modification, which is required by existing methods for making muscle cells.

"Many other protocols have been used to enhance the number of cells that go to a muscle fate," says co-author Jonathan Van Dyke, a post-doctoral fellow in Suzuki's laboratory.

"But what's exciting about the new protocol is that we avoid some techniques that would prohibit clinical applications. We think this new method has great promise for alleviating human suffering."

Last year, Suzuki demonstrated that transplants of another type of human stem cells somewhat improved survival and muscle function in rats that model amyotrophic lateral sclerosis (ALS). Also known as Lou Gehrig's disease, ALS destroys nerves and causes a loss of muscle control. The muscle progenitors generated with Suzuki's new method could potentially play a similar role but with enhanced effect.

The new technique can also be used to grow muscle cells from iPS cells from patients with neuromuscular diseases like ALS, spinal muscular atrophy and muscular dystrophy. Thus, the technique could produce adult muscle cells in a dish that carry genetic diseases. These cells could then be used as a tool for studying these diseases and screening potential drug compounds, says Suzuki.

"Our protocol can work in multiple ways and so we hope to provide a resource for people who are exploring specific neuromuscular diseases in the laboratory."

The new protocol incorporates a number of advantages. First, the cells are grown in defined supplements without animal products such as bovine serum, enhancing the clinical safety for the muscle stem cells. Second, when grown as spheres, the cells grow faster than with previous techniques. Third, 40 to 60 percent of the cells grown using the process are either muscle cells or muscle progenitors, a high proportion compared to traditional non-genetic techniques of generating muscle cells from human ES and iPS cells.

Suzuki and his group hope that by further manipulating the chemical environment of the spheres of stem cells, they may increase that number, further easing the path toward human treatment.

Source: University of Wisconsin-Madison 

Contact: Masatoshi Suzuki

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Reinventing Drug Discovery using Stem Cells

Promising drug target for ALS

Thursday, 18 April 2013

Using a new stem-cell based drug screening technology with the potential to reinvent and greatly reduce the cost of the way new pharmaceuticals are developed, Harvard Stem Cell Institute (HSCI) researchers have found a compound more effective in protecting the neurons killed in amyotrophic lateral sclerosis (ALS) – Lou Gehrig's disease – than two drugs that failed in human clinical trials after hundreds of millions of dollars had been invested in them.

The new stem cell screening technique developed by Lee Rubin, a member of HSCI's Executive Committee and a professor in Harvard's Department of Stem Cell and Regenerative Biology, successfully predicted that the two drugs that eventually failed in the third and final stage of human testing would, in fact, fail.

"It's a deep, dark secret of drug discovery that very few drugs have been tested on human-diseased cells before being tested in a live person," said Rubin, who heads HSCI's program in translational medicine.

"We were interested in the notion that we can use stem cells to correct that situation."

Rubin's model is built on an earlier proof-of-concept developed by HSCI Principal Faculty member Kevin Eggan, who demonstrated that it was possible to move a neuron-based disease into a laboratory dish using stem cells carrying the genes of patients with the disease.

The c-Jun-mediated cell death pathway (marked

by red nuclei that are positive for phospho-cjun) is

activated in stem cell-derived motor neurons (green)

exposed to trophic factor withdrawal (upper left panel).

C-Jun activation and cell death are blocked by

kenpaullone, an inhibitor GSK-3 and HGK (MAP4K4)

kinases (lower right panel; kenpaullone structure

superimposed). Credit: Cell Stem Cell, Yang et al..

In a paper published today in the journal Cell Stem Cell, Rubin lays out how he and his colleagues applied their new method of stem cell-based drug discovery to ALS. The disease is associated with the progressive death of motor neurons, which pass information between the brain and the muscles. As cells die, people with ALS experience weakness in their limbs followed by rapid paralysis and respiratory failure. The disease typically strikes later in life. Ten percent of cases are genetically predisposed, but for most patients there is no known trigger.

Rubin's lab began by first studying the disease in mice, growing billions of motor neurons from mouse embryonic stem cells, half normal and half with a genetic mutation known to cause ALS.

Investigators starved the cells of nutrients and then screened five thousand drug-like molecules to find any that would keep the motor neurons alive.

Several hits were identified, but the molecule that best prolonged the life of both normal and ALS motor neurons was kenpaullone, previously known for blocking the action of an enzyme (GSK-3) that switches on and off several cellular processes, including cell growth and death.

"Shockingly, this molecule keeps cells alive better than the standard culture medium that everybody keeps motor neurons in," Rubin said.

Kenpaullone proved effective in several follow-up experiments that put mouse motor neurons in situations of certain death. Neuron survival increased in the presence of the molecule whether the cells were programmed to die or placed in a toxic environment.

After further investigation, Rubin's lab discovered kenpaullone's potency comes from its ability to also inhibit HGK – an enzyme that sets off a chain of reactions that leads to motor neuron death. This enzyme was not previously known to be important in motor neurons or associated with ALS, marking the discovery of a new drug target for the disease.

"I think that stem-cell screens will discover new compounds that have never been discovered before by other methods," Rubin said.

"I'm excited to think that someday one of them might actually be good enough to go into the clinic."

To find out if kenpaullone works in diseased human cells, Rubin's lab exposed patient motor neurons and motor neurons grown from human embryonic stem cells to the molecule, as well as two drugs that did well in mice but failed in phase III human clinical trials for ALS. Once again, kenpaullone increased the rate of neuron survival, while one drug saw little response, and the other drug failed to keep any cells alive.

According to Rubin, before kenpaullone could be used as a drug, it would need a substantial molecular makeover to make it better able to target cells and find its way into the spinal cord so it can access motor neurons.

"This is kind of a proof of principle on the do-ability of the whole thing," he said.

"I think it's possible to use this method to discover new drug targets and to pre-validate compounds on real human disease cells before putting them in the clinic."

In the meantime, Rubin's next steps will be to continue searching for better drug-like compounds that can inhibit HGK and thus enhance motor neuron survival. He believes that the new information that comes out of this research will be useful to academia and the pharmaceutical industry.

"These kinds of exploratory screens are hard to fund, so being part of the HSCI" – which provided some of the funding – "has been absolutely essential," Rubin said.

Source: Harvard University 

Contact: B. D. Colen

Reference:

A Small Molecule Screen in Stem-Cell-Derived Motor Neurons Identifies a Kinase Inhibitor as a Candidate Therapeutic for ALS

Yin M. Yang, Shailesh K. Gupta, Kevin J. Kim, Berit E. Powers, Antonio Cerqueira, Brian J. Wainger, Hien D. Ngo, Kathryn A. Rosowski, Pamela A. Schein, Courtney A. Ackeifi, Anthony C. Arvanites, Lance S. Davidow, Clifford J. Woolf, and Lee L. Rubin
Cell Stem Cell 18 April 2013, 10.1016/j.stem.2013.04.003

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New York’s Investment in Stem Cell Research

Program generate new medical treatments and innovative research

Sunday, 06 May 2012

The Associated Medical Schools of New York (AMSNY) today released a 2012 report showing how New York’s stem cell program has enabled it to emerge as a leader in stem cell research, and strengthened the state’s economy through job creation.

“This report demonstrates the foresight of New York’s leaders in funding stem cell research. Not only are scientists across the state making progress towards understanding how to treat or prevent debilitating diseases, New York’s stem cell program generates jobs, attracts promising young women and men into medical and scientific careers, and enhances our state’s leadership in biomedical research,” said Dr. Lee Goldman, AMSNY’s chair, and executive vice president and dean of the Columbia University College of Physicians & Surgeons.

In 2007, New York State allocated $600 million over 11 years to the Empire State Stem Cell Program (NYSTEM), making it the second largest publically-financed stem cell program in the country. To date, New York has awarded nearly $223 million of the $600 million to support stem cell research for the purpose of exploring innovative cures and treatment to life threatening and chronic illnesses, such as Alzheimer’s, and Arterial Lateral Sclerosis (ALS).

In addition to supporting ground-breaking stem cell research projects, the state’s investment has been a tool for economic development by creating or maintaining more than 400 jobs at AMSNY institutions since the program’s inception, and is attracting world-renowned researchers and scientists to New York.

Dr. Ronald G. Crystal, chairman and professor of Genetic Medicine, Weill Cornell Medical College, said:

“Stem cell research holds the promise of tomorrow’s medical breakthroughs to improve human health. Continuing to advance stem cell research in New York is vital since we are one of the strongest and largest centres of stem cell science in the world and home to some of the most talented medical researchers. Funding for stem cell research in New York is critical and any reduction in support will slow our progress toward securing the important discoveries and cures for the devastating diseases that affect New Yorkers.”

Dr. Allen M. Spiegel, dean of Albert Einstein College of Medicine said:

“The Albert Einstein College of Medicine has made a major commitment to the stem cell research field because it offers tremendous potential for understanding the causes of and developing better treatments for diseases like cancer, type 1 diabetes, and Parkinson's. The NYSTEM program has been critical in helping Einstein support innovative and technically advanced work in this vital field.”

Dennis S. Charney, MD, Anne and Joel Ehrenkranz Dean, Mount Sinai School of Medicine, and executive vice president for Academic Affairs at the Mount Sinai Medical Center said:

“Stem cell research has the potential to transform the way medicine is practiced and it is an area that has been one of Mount Sinai’s top priorities. Our researchers at the Black Family Stem Cell Institute, with funding from The Empire State Stem Cell Program, were the first to develop abnormal heart cells from human stem cells, allowing them to study potential treatments for cardiomyopathy. Maintaining funding for stem cell research is essential to the continued success of our research programs which, in addition to studying heart disease, include researching potential treatments for schizophrenia, autism, Alzheimer’s disease and diabetes.”

Ruth Lehmann, PhD, Director of the Kimmel Center for Stem Cell Biology and the Skirball Institute of Biomolecular Medicine at NYU School of Medicine, part of the NYU Langone Medical Center, said:

“In the current political and economic climate, where the government’s funding choices are being scrutinized, it is important to realize the impact of continuing to support early stage research and development, particularly in stem cell biology. The majority of scientific and medical discoveries originate in early stage laboratory research. By focusing its support on early stage research, NYSTEM has attracted new researchers to the field of stem cell biology who are bringing creative ideas and new approaches to this important field. At NYU Langone, this support has contributed to understanding the underlying causes of leukaemia and to developing new approaches for cancer stem cell therapies. Without this funding, academic medical centres cannot thrive, and our leadership as innovators in health and science is threatened.”

According to the report, New York’s funding commitment is critical to the state’s stem cell research and patient communities given its unique nature. NYSTEM funds early stage projects that have not been able to access other funding sources such as those granted by the National Institutes of Health (NIH). NYSTEM also is distinct among other research grants in that it provides funding for capital projects and equipment, allowing institutions to develop or expand their stem cell research infrastructure.

“NYSTEM has made it possible for cutting-edge stem cell research to thrive in New York,” said Jo Wiederhorn, AMSNY’s president and CEO.

“Across the state, medical schools and research institutions have been renovating laboratories and building state-of-the-art stem cell centers – spurring economic development and fostering medical innovation. None of this would have been possible without NYSTEM.”

The program also has stimulated state research institutions to make their own investments in stem cell research, which in turn has improved their ability to win additional NIH grants and attract private sector and philanthropic funding.

Source: AMSNY 2012 STEM Cell Report

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Grafting of Human Spinal Stem Cells into ALS Rats Best with Immunosuppressant Combination

Grafting of Human Spinal Stem Cells into ALS Rats Best with Immunosuppressant Combination  
Monday, 19 December 2011

A team of researchers grafting human spinal stem cells into rats modeled with amyotrophic lateral sclerosis (ALS), also known as "Lou Gehrig's Disease," a degenerative, lethal, neuromuscular disease, have tested four different immunosuppressive protocols aimed at determining which regimen improved long-term therapeutic effects. Their study demonstrated that a combined, systematically delivered immunosuppression regimen of two drugs significantly improved the survival of the human spinal stem cells. Their results are published in the current issue of Cell Transplantation (20:8).

"There are no therapeutic strategies that successfully modify ALS progression or outcome," said study corresponding author Dr. Michael P. Hefferan of the University of California at San Diego Neurodegeneration Laboratory.

"Cell-based transplantation therapies have emerged as potential treatments for several neurological disorders, including ALS. However, cell graft survival seems to greatly depend on an accompanying immunosuppression regimen, yet there are differential responses to identical immunosuppressive therapies."

While the reason for this differential response is unclear, the study authors suggest that several mechanisms, including distinct types of acute and inflammatory responses, may be to blame.

Their study aimed at optimizing an immunosuppressive protocol for transplanting human spinal cord cells into pre-symptomatic ALS G93A rats with the G93A superoxide dismutase (SOD1) mutation. Two drugs, tacrolimus (FK506) and mycophenolate, were used alone and in combination.

"Although FK506 has been used successfully as monotherapy in our previous studies of spinal ischemia, it failed in the present study on ALS," explained Dr. Hefferan, who speculated that inflammation played a role in the failure.

"In contrast to ALS, where spinal inflammation continues and likely worsens until end stage, the traumatically-injured spinal cord is typically characterized by an acute inflammatory phase followed by a progressive loss of most inflammatory markers."

According to the researchers, the animals receiving combined immunosuppression of both FK506 and mycophenolate likely benefited from the longer half-life of mycophenolate rather than from its action.

"The addition of mycophenolate seemed to supplement inhibition of T-cell formation and led to a robust graft survival when analyzed three weeks after grafting," concluded Dr. Hefferan.

Source: Cell Transplantation Center of Excellence for Aging and Brain Repair

Contact: David Eve

Reference:

Optimization of Immunosuppressive Therapy for Spinal Grafting of Human Spinal Stem Cells in a Rat Model of ALS
Hefferan, M. P.; Johe, K.; Hazel, T.; Feldman, E. L.; Lunn, J. S.; Marsala, M.
Cell Transplant. 20(8):1153-1161; 2011
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Researchers Turn Embryonic Stem Cells into Functioning Neurons

Implanted neurons, grown in the lab, take charge of brain circuitry 
Tuesday, 22 November 2011

Among the many hurdles to be cleared before human embryonic stem cells can achieve their therapeutic potential is determining whether or not transplanted cells can functionally integrate into target organs or tissues.

Writing today (Monday, Nov. 21) in the Proceedings of the National Academy of Sciences, a team of Wisconsin scientists reports that neurons, forged in the lab from blank slate human embryonic stem cells and implanted into the brains of mice, can successfully fuse with the brain's wiring and both send and receive signals.

Neurons are specialized, impulse conducting cells that are the most elementary functional unit of the central nervous system. The 100 billion or so neurons in the human brain are constantly sending and receiving the signals that govern everything from walking and talking to thinking. The work represents a crucial step toward deploying customized cells to repair damaged or diseased brains, the most complex human organ.

"The big question was can these cells integrate in a functional way," says Jason P. Weick, the lead author of the new study and a staff scientist at the University of Wisconsin-Madison's Waisman Center.

"We show for the first time that these transplanted cells can both listen and talk to surrounding neurons of the adult brain."

The Wisconsin team tested the ability of their lab grown neurons to integrate into the brain's circuitry by transplanting the cells into the adult mouse hippocampus, a well-studied region of the brain that plays a key role in processing memory and spatial navigation. The capacity of the cells to integrate was observed in live tissue taken from the animals that received the cell transplants.

Weick and colleagues also reported that the human neurons adopted the rhythmic firing behavior of many brain cells talking to one another in unison. And, perhaps more importantly, that the human cells could modify the way the neural network behaved.

A critical tool that allowed the UW group to answer this question was a new technology known as optogenetics, where light, instead of electric current, is used to stimulate the activity of the neurons.

"Previously, we've been limited in how efficiently we could stimulate transplanted cells. Now we have a tool that allows us to specifically stimulate only the transplanted human cells, and lots of them at once in a non-invasive way," says Weick.

Weick explains that the capacity to modulate the implanted cells was a necessary step in determining the function of implanted cells because previous technologies were too imprecise and unreliable to accurately determine what transplanted neurons were doing.

Embryonic stem cells, and the closely related induced pluripotent stem cells can give rise to all of the 220 types of tissues in the human body, and have been directed in the lab to become many types of cells, including brain cells.

The appeal of human embryonic stem cells and induced pluripotent cells is the potential to manufacture limitless supplies of healthy, specialized cells to replace diseased or damaged cells. Brain disorders such as Parkinson's disease and amyotrophic lateral sclerosis, more widely known as Lou Gehrig's disease, are conditions that scientists think may be alleviated by using healthy lab grown cells to replace faulty ones. Multiple studies over the past decade have shown that both embryonic stem cells and induced cells can alleviate deficits of these disorders in animal models.

The new study opens the door to the potential for clinicians to deploy light-based stimulation technology to manipulate transplanted tissue and cells.

"The marriage between stem cells and optogenetics has the potential to assist in the treatment of a number of debilitating neurodegenerative disorders," notes Su-Chun Zhang, a UW-Madison professor of neuroscience and one of the authors of the new PNAS report.

"You can imagine that if the transplanted cells don't behave as they should, you could use this system to modulate them using light."

Source: University of Wisconsin-Madison

Contact: Jason P. Weick

Reference:

Human embryonic stem cell-derived neurons adopt and regulate the activity of an established neural network
Jason P. Weick, Yan Liu, and Su-Chun Zhang
Proceedings of the National Academy of Sciences, November 21, 2011, doi:10.1073/pnas.1108487108
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ZenMaster

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For more on stem cells and cloning, go to CellNEWS at

http://cellnews-blog.blogspot.com/

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Stem Cell Model of Inherited ALS

Offers clues to cause of the disease
Wednesday, 22 June 2011

An international team of scientists led by researchers at the University of California, San Diego School of Medicine, have used induced pluripotent stem cells (iPSCs) derived from patients with amyotrophic lateral sclerosis (ALS). This work reveals for the first time how reduced levels of a specific protein may play a central role in causing at least one inherited form of the disease.

The work, published in the June 2011 online issue of the journal Human Molecular Genetics, could help scientists overcome a major hurdle in the study and treatment of ALS, an incurable neuromuscular disorder also known as Lou Gehrig's disease. ALS is universally fatal, with a median age of onset of 55 years and survival of two to five years after symptoms appear. Past research efforts have long been stymied by difficulties in translating successful drug tests in animal models of ALS to humans.

"There is an urgent need for ALS human models that can be translated into clinical trials to verify therapeutic targets in the human genetic background," said Alysson R. Muotri, PhD, assistant professor in the UCSD Departments of Pediatrics and Cellular and Molecular Medicine, and one of the study's senior authors.

"Rodents have been used in the past and still have a critical impact in unveiling the complexity of ALS, but the vast majority of drugs that have demonstrated efficacy in rodent models have not done the same in preclinical and clinical human trials."

In the new work, Muotri and colleagues turned to iPSCs derived from the skin cells of patients with a familial form of ALS called ALS8 to create motor neurons that provided a novel in vitro model of the disease. iPSCs from ALS patients have been described before, but finding cellular and molecular phenotypes has proved to be a continuing challenge. The use of a familial form of ALS offered an advantage since the mutated gene could be tracked during motor neuron differentiation.

"We don't know what causes most cases of ALS, but for roughly 10 percent of patients with ALS, the disease is the result of inherited genetic mutations," Muotri said.

"One of these familial forms is ALS8, which results from mutations in the VAPB gene. Using iPSCs from several patients from two independent families, we found that VAPB protein levels are reduced in ALS8-derived motor neurons compared to similar cells from non-carrier siblings of ALS8 patients."

Muotri said the finding suggests reduced VAPB protein levels may be a key to the development of ALS8 and perhaps other forms of the disease as well, including sporadic or non-hereditary ALS, where reduced VAPB protein levels have also been documented.

"The VAPB protein is involved in many cellular processes, so it seems likely it contributes to the pathogenesis of other forms of ALS," Muotri said.

"We don't yet know how the loss of VAPB is involved in causing familial or sporadic ALS, but the new ability to study this disease in human cells provides an unprecedented opportunity to answer that question, to develop new early diagnostic tools and to identify new targets for future drugs and therapies."

About ALS
Amyotrophic lateral sclerosis is a rapidly progressive, invariably fatal neurological disease that attacks the neurons responsible for controlling voluntary muscle movement. It does not generally impair cognitive function. An estimated 20,000 to 30,000 Americans have ALS, with 5,000 new cases diagnosed each year. ALS strikes most commonly between the ages of 40 and 60, affecting men more often than women, but with no distinction of race or ethnic background. In 90 percent of all ALS cases, the disease appears to occur randomly without clearly associated risk factors. Ten percent of cases are inherited, due to gene mutations.


Source: University of California at San Diego
Contact: Scott LaFee

Reference:
Downregulation of VAPB expression in motor neurons derived from induced pluripotent stem-cells of ALS8 patients
Miguel Mitne-Neto, Marcela Machado-Costa, Maria C. N. Marchetto, Mario H. Bengtson, Claudio A. Joazeiro, Hiroshi Tsuda, Hugo J. Bellen, Helga A. C. Silva, Acary S.B. Oliveira, Monize Lazar, Alysson R. Muotri, and Mayana Zatz Hum. Mol. Genet. (2011) ddr284 first published online June 17, 2011 doi:10.1093/hmg/ddr284
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ZenMaster

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For more on stem cells and cloning, go to CellNEWS at
http://cellnews-blog.blogspot.com/

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