The invention of GPS navigation systems has made finding your way around so much easier, providing simple instructions on how to get from point A to point B. Now, a new study shows that our bodies have their own internal navigation system that helps stem cells know where to go, and when, in order to build a human heart. And the study also shows what can go wrong when even a few cells fail to follow directions.
In this CIRM-supported study, a team of researchers at the Gladstone Institutes in San Francisco, used a new technique called single cell RNA sequencing to study what happens in a developing heart. Single cell RNA sequencing basically takes a snapshot photo of all the gene activity in a single cell at one precise moment. Using this the researchers were able to follow the activity of tens of thousands of cells as a human heart was being formed.
“This sequencing technique allowed us
to see all the different types of cells present at various stages of heart development
and helped us identify which genes are activated and suppressed along the way. We
were not only able to uncover the existence of unknown cell types, but we also
gained a better understanding of the function and behavior of individual
cells—information we could never access before.”
Then they partnered with a team at Luxembourg Centre for Systems
Biomedicine (LCSB) of the University of Luxembourg which ran a
computational analysis to identify which genes were involved in creating
different cell types. This highlighted one specific gene, called Hand2, that controls
the activity of thousands of other genes. They found that a lack of Hand2 in
mice led to an inability to form one of the heart’s chambers, which in turn led
to impaired blood flow to the lungs. The embryo was creating the cells needed
to form the chamber, but not a critical pathway that would allow those cells to
get where they were needed when they were needed.
Gifford says this has given us a deeper insight into how
cells are formed, knowledge we didn’t have before.
“Single-cell technologies can inform us about how organs
form in ways we couldn’t understand before and can provide the underlying cause
of disease associated with genetic variations. We revealed subtle differences
in very, very small subsets of cells that actually have catastrophic
consequences and could easily have been overlooked in the past. This is the
first step toward devising new therapies.”
These therapies are needed to help treat congenital heart
defects, which are the most common and deadly birth defects. There are more
than 2.5 million Americans with these defects. Deepak Srivastava, President of
Gladstone and the leader of the study, said the knowledge gained in this study
could help developed strategies to help address that.
to see the long-term consequences in adults, and right now, we don’t really
have any way to treat them. My hope is that if we can understand the genetic
causes and the cell types affected, we could potentially intervene soon after
birth to prevent the worsening of their state over time.
Students present their research finding at the 2016 CIRM Bridges conference
One of the programs people here at CIRM love is our Bridges to Stem Cell Research Awards. These are given to undergraduate and master’s level college students, to train the next generation of stem cell scientists. How good a program is it? It’s terrific. You don’t have to take my word for it. Just read this piece by a great stem cell champion, Don Reed. Don is the author of two books about CIRM, Stem Cell Battles and California Cures! so he clearly knows what he’s talking about.
ADVENTURES ON “BRIDGES”: Humboldt State Stem Cell Research
By Don C. Reed
Imagine yourself as a California college student, hoping to become a stem cell researcher. Like almost all students you are in need of financial help, and so (let’s say) you asked your college counselor if there were any scholarships available.
To your delight, she said, well, there is this wonderful internship program called Bridges, funded by the California Institution for Regenerative Medicine (CIRM) which funds training in stem cell biology and regenerative medicine — and so, naturally, you applied…
After doing some basic training at the college, you would receive a grant (roughly $40,000) for a one-year internship at a world-renowned stem cell research facility. What an incredible leap forward in your career, hands-on experience (essentially a first job, great “experience” for the resume) as well an expert education.
Where are the 14 California colleges participating in this program? Click below:
Let’s take a look at one of these college programs in action: find out what happened to a few of the students who received a Bridges award, crossing the gap between studying stem cell research and actually applying it.
HSU information is courtesy of Dr. Amy Sprowles, Associate Professor of Biological Sciences and Co-Director of the Bridges program at Humboldt State University (HSU), 279 miles north of San Francisco.
“The HSU Bridges program”, says Dr. Sprowles, “was largely developed by four people: Rollin Richmond, then HSU President, who worked closely with Susan Baxter, Executive Director of the CSU Program for Education and Research in Biotechnology, to secure the CIRM Bridges initiative; HSU Professor of Biological Sciences Jacob Varkey, who pioneered HSU’s undergraduate biomedical education program”, and Sprowles herself, at the time a lecturer with a PhD in Biochemistry.
The program has two parts: a beginning course in stem cell research, and a twelve-month internship in a premiere stem cell research laboratory. For HSU, these are at Stanford University, UC Davis, UCSF, or the Scripps Research Institute.
Like all CIRM Bridges programs, the HSU stem cell program is individually designed to suit the needs of its community.
Each of the 15 CIRM Bridges Programs fund up to ten paid internships, but the curriculum and specific activities of each are designed by their campus directors. The HSU program prepares Bridges candidates by requiring participation in a semester-long lecture and stem cell biology laboratory course before selection for the program: a course designed and taught by Sprowles since its inception.
She states, “The HSU pre-internship course ensures our students are trained in fundamental scientific concepts, laboratory skills and professional behaviors before entering their host laboratory. We find this necessary since, unlike the other Bridges campuses, we are 300+ miles away from the internship sites and are unable to fully support this kind of training during the experience. It also provides additional insights about the work ethic and mentoring needs of the individuals we select that are helpful in placing and supporting our program participants”.
How is it working?
Ten years after it began, 76 HSU students have completed the CIRM Bridges program at HSU. Of those, the overwhelming majority (over 85%) are committed to careers in regenerative medicine: either working in the field already, or continuing their education toward that goal.
But what happened to their lives? Take a brief look at the ongoing careers of a “Magnificent Seven” HSU Bridges scientists:
CARSTEN CHARLESWORTH: “Spurred by the opportunity to complete a paid internship at a world class research institution in Stem Cell Biology, I applied to the Humboldt CIRM Bridges program, and was lucky enough to be accepted. With a keen interest in the developing field of genome editing and the recent advent of the CRISPR-Cas9 system I chose to intern in the lab of a pioneer in the genome editing field, Dr. Matthew Porteus at Stanford, who focuses in genome editing hematopoietic stem cells to treat diseases such as sickle cell disease. In August of 2018 I began a PhD in Stanford’s Stem Cell and Regenerative Medicine program, where I am currently a second-year graduate student in the lab of Dr. Hiro Nakauchi, working on the development of human organs in interspecies human animal chimeras. The success that I’ve had and my acceptance into Stanford’s world class PhD program are a direct result of the opportunity that the CIRM Bridges internship provided me and the excellent training and instruction that I received from the Humboldt State Biology Program.”
ELISEBETH TORRETTI: “While looking for opportunities at HSU, I stumbled upon the CIRM Bridges program. It was perfect- a paid internship at high profile labs where I could expand my research skills for an entire year… the best fit (was) Jeanne Loring’s Lab at the Scripps Research Institute in La Jolla, CA. Dr. Loring is one of the premiere stem cell researchers in the world… (The lab’s) main focus is to develop a cure for Parkinson’s disease. (They) take skin cells known as fibroblasts and revert them into stem cells. These cells, called induced pluripotent stem cells (iPSCs) can then be differentiated into dopaminergic neurons and transplanted into the patient…. My project focused on a different disease: adenylate-cyclase 5 (ADCY5) — related dyskinesia. During my time at Dr. Loring’s lab I learned incredibly valuable research skills. I am now working in a mid-sized biotch company focusing on cancer research. I don’t think that would be possible in a competitive area like San Diego without my experience gained through the CIRM Bridges program.”
BRENDAN KELLY: “After completing my CIRM internship in Dr. Marius Wernig’s lab (in Stanford), I began working at a startup company called I Peace. I helped launch this company with Dr. Koji Tanabe, whom I met while working in my host lab. I am now at Cardiff University in Wales working on my PhD. My research involves using patient iPSC derived neurons to model Huntington’s disease. All this derived from my opportunity to partake in the CIRM-Bridges program, which opened doors for me.”
SAMANTHA SHELTON: “CIRM Bridges provided invaluable hands-on training in cell culture and stem cell techniques that have shaped my future in science. My CIRM internship in John Rubenstein’s Lab of Neural Development taught me amazing laboratory techniques such as stem cell transplantation as well as what goes into creating a harmonious and productive laboratory environment. My internship projects led to my first co-first author publication.
After my Bridges internship, I joined the Graduate Program for Neuroscience at Boston University. My PhD work aims to discover types of stem cells in the brain and how the structure of the brain develops early in life. During this time, I have focused on changes in brain development after Zika virus infection to better understand how microcephaly (small skulls and brains, often a symptom of Zika-DR) is caused. There is no doubt that CIRM not only made me a more competitive candidate for a doctoral degree but also provided me with tools to progress towards my ultimate goal of understanding and treating neurological diseases with stem cell technologies.”
DU CHENG: “Both my academic and business tracks started in the CIRM-funded…fellowship (at Stanford) where I invented the technology (the LabCam Microscope adapter) that I formed my company on (iDU Optics LLC). The instructor of the class, Dr. Amy Sprowles, encouraged me to carry on the idea. Later, I was able to get in the MD-PhD program at Weill Cornell Medical College because of the invaluable research experiences CIRM’s research program provided me. CIRM initiated the momentum to get me where I am today. Looking back, the CIRM Bridges Program is an instrumental jump-starter on my early career… I would not remotely be where I am without it.…”
CODY KIME: “Securing a CIRM grant helped me to take a position in the Nobel Prize winning Shinya Yamanaka Lab at the Gladstone Institutes, one of the most competitive labs in the new field of cell reprogramming. I then explored my own reprogramming interests, moving to the Kyoto University of Medicine, Doctor of Medical Sciences Program in Japan, and building a reprogramming team in the Masayo Takahashi Lab at RIKEN. My studies explore inducing cells to their highest total potential using less intrusive means and hacking the cell program. My systems are designed to inform my hypotheses toward a true お好みの細胞 (okonomi no cybo) technology, meaning ‘cells as you wish’ in Japanese, that could rapidly change any cell into another desired cell type or tissue.”
SARA MILLS: “The CIRM Bridges program was the key early influencer which aided in my hiring of my first industry position at ViaCyte, Inc. Also a strongly CIRM funded institution, I was ultimately responsible for the process development of the VC-01™ fill, finish processes and cGMP documentation development. Most recently, with over two years at the boutique consulting firm of Dark Horse Consulting, Inc., I have been focusing on aseptic and cGMP manufacturing process development, risk analysis, CMC and regulatory filings, facility design and project management to advise growing cell and gene therapy companies, worldwide.”
Like warriors fighting to save lives, these young scientists are engaged in an effort to study and defeat chronic disease. It is to be hoped the California stem cell program will have its funding renewed, so the “Bridges” program can continue.
For more information on the Bridges program, which might help a young scientist (perhaps yourself) cut and paste the following URL:
One closing paragraph perhaps best sums up the Bridges experience:
“During my CIRM Bridges training in Stanford University, I was fortunate to work with Dr. Jill Helms, who so patiently mentored me on research design and execution. I ended up publishing 7 papers with her during the two-year CIRM internship and helped making significant progress of turning a Stem Cell factor into applicable therapeutic form, that is currently in preparation for clinical trial by a biotech company in Silicon Valley. I also learned from her how to write grants and publications, but more importantly, (to) never limit your potential by what you already know.” — Du Cheng
The news that President Trump’s administration has told scientists employed by the National Institutes of Health (NIH) that they can’t buy any new human fetal tissue for research has left many scientists frustrated and worried.
The news has also highlighted the reason why voters created CIRM in the first place and the importance of having an independent source of funding for potentially life-saving research such as this.
The Trump administration imposed the suspension of all new acquisitions saying it wants to review all fetal tissue research funded by the federal government. The impact was felt immediately.
In an article on ScienceMag.com, Warner Greene, director of the Center for HIV Cure Research at the Gladstone Institutes in San Francisco, said the decision derailed collaboration between his lab and one at Rocky Mountain Laboratories in Hamilton, Montana. The research focused on an antibody that previous studies showed might prevent HIV from establishing reservoirs in the human body.
“We were all poised to go and then the bombshell was dropped. The decision completely knocked our collaboration off the rails. We were devastated.”
Right now, it’s not clear if the “halt” is temporary or permanent, or if it will ultimately be expanded beyond scientists employed by the NIH to all scientists funded by the NIH who use fetal tissue.
In 2001, President George W. Bush’s decision to impose restrictions on federal funding for embryonic stem cell research helped generate support for Proposition 71, the voter-approved initiation that created CIRM. People felt that stem cell research had potential to develop treatments and cures for deadly diseases and that if the federal government wasn’t going to support it then California would.
CIRM Board member, and Patient Advocate for HIV/AIDS, Jeff Sheehy says the current actions could have wide-reaching impact.
“While the initial focus of the emerging ban on the use of fetal tissue has been on projects related to HIV, this action undermines a spectrum of vital research initiatives that seek to cure multiple life-threatening diseases and conditions. Many regenerative medicine cell-based or gene therapies require pre-clinical safety studies in humanized mice created with fetal tissue. These mice effectively have human immune systems, which allows researchers to examine the effects of products on the immune system. Work to prevent and treat infectious diseases, including vaccine efforts, require this animal model to do initial testing. Development of vaccines to respond to actual threats requires use of this animal model. This action could have damaging effects on the health of Americans.”
Do we know how to pick ‘em or what? For a number of years now we have been funding the work of Stanford’s Dr. Marius Wernig, who is doing groundbreaking work in helping advance stem cell research. Just how groundbreaking was emphasized this week when he was named as the winner of the 2018 Ogawa-Yamanaka Stem Cell Prize.
Marius Wernig, MD, PhD. [Photo: Stanford University]
The prestigious award, from San Francisco’s Gladstone Institutes, honors Wernig for his innovative work in developing a faster, more direct method of turning ordinary cells into, for example, brain cells, and for his work advancing the development of disease models for diseases of the brain and skin disorders.
Dr. Deepak Srivastava, the President of Gladstone, announced the award in a news release:
“Dr. Wernig is a leader in his field with extraordinary accomplishments in stem cell reprogramming. His team was the first to develop neuronal cells reprogrammed directly from skin cells. He is now investigating therapeutic gene targeting and cell transplantation–based strategies for diseases with mutations in a single gene.”
Wernig was understandably delighted at the news:
“It is a great honor to receive this esteemed prize. My lab’s goal is to discover novel biology using reprogrammed cells that aids in the development of effective treatments.”
Wernig will be presented with the award, and a check for $150,000, at a ceremony on Oct. 15 at the Gladstone Institutes in San Francisco.
A stem cell trifecta for teeth research
It was a tooth trifecta among stem cell scientists this week. At Tufts University School of Medicine, researchers made an important advance in the development of bioengineered teeth. The current standard for tooth replacement is a dental implant. This screw-shaped device acts as an artificial tooth root that’s inserted into the jawbone. Implants have been used for 30 years and though successful they can lead to implant failure since they lack many of the properties of natural teeth. By implanting postnatal dental cells along with a gel material into mice, the team demonstrated, in a Journal of Dental Research report, the development of natural tooth buds. As explained in Dentistry Today, these teeth “include features resembling natural tooth buds such as the dental epithelial stem cell niche, enamel knot signaling centers, transient amplifying cells, and mineralized dental tissue formation.”
Another challenge with the development of a bioengineered tooth replacement is reestablishing nerve connections within the tooth, which plays a critical role in its function and protection but doesn’t occur spontaneously after an injury. A research team across the “Pond” at the French National Institute of Health and Medical Research, showed that bone marrow-derived mesenchymal stem cells in the presence of a nerve fiber can help the nerve cells make connections with bioengineered teeth. The study was also published in the Journal of Dental Research.
And finally, a research report about stem cells and the dreaded root canal. When the living soft tissue, or dental pulp, of a tooth becomes infected, the primary course of action is the removal of that tissue via a root canal. The big downside to this procedure is that it leaves the patient with a dead tooth which can be susceptible to future infections. To combat this side effect, researchers at the New Jersey Institute of Technology report the development of a potential remedy: a gel containing a fragment of a protein that stimulates the growth of new blood vessels as well as a fragment of a protein that spurs dental stem cells to divide and grow. Though this technology is still at an early stage, it promises to help keep teeth alive and healthy after root canal. The study was presented this week at the National Meeting of the American Chemical Society.
Here’s an animated video that helps explain the research:
A program hoping to supercharge a patient’s own immune system cells to attack and kill a treatment resistant form of prostate cancer was today awarded $3.99 million by the governing Board of the California Institute for Regenerative Medicine (CIRM)
In the U.S., prostate cancer is the second most common cause of cancer deaths in men. An estimated 170,000 new cases are diagnosed each year and over 29,000 deaths are estimated in 2018. Early stage prostate cancer is usually managed by surgery, radiation and/or hormone therapy. However, for men diagnosed with castrate-resistant metastatic prostate cancer (CRPC) these treatments often fail to work and the disease eventually proves fatal.
Poseida Therapeutics will be funded by CIRM to develop genetically engineered chimeric antigen receptor T cells (CAR-T) to treat metastatic CRPC. In cancer, there is a breakdown in the natural ability of immune T-cells to survey the body and recognize, bind to and kill cancerous cells. Poseida is engineering T cells and T memory stem cells to express a chimeric antigen receptor that arms these cells to more efficiently target, bind to and destroy the cancer cell. Millions of these cells are then grown in the laboratory and then re-infused into the patient. The CAR-T memory stem cells have the potential to persist long-term and kill residual cancer calls.
“This is a promising approach to an incurable disease where patients have few options,” says Maria T. Millan, M.D., President and CEO of CIRM. “The use of chimeric antigen receptor engineered T cells has led to impressive results in blood malignancies and a natural extension of this promising approach is to tackle currently untreatable solid malignancies, such as castrate resistant metastatic prostate cancer. CIRM is pleased to partner on this program and to add it to its portfolio that involves CAR T memory stem cells.”
Poseida Therapeutics plans to use the funding to complete the late-stage testing needed to apply to the Food and Drug Administration for the go-ahead to start a clinical trial in people.
The CIRM Board also voted to approve investing $10 million for eight projects under its Discovery Quest Program. The Quest program promotes the discovery of promising new stem cell-based technologies that will be ready to move to the next level, the translational category, within two years, with an ultimate goal of improving patient care.
Among those approved for funding are:
Eric Adler at UC San Diego is using genetically modified blood stem cells to treat Danon Disease, a rare and fatal condition that affects the heart
Li Gan at the Gladstone Institutes will use induced pluripotent stem cells to develop a therapy for a familial form of dementia
Saul Priceman at City of Hope will use CAR-T therapy to develop a treatment for recurrent ovarian cancer
Because the amount of funding for the recommended applications exceeded the money set aside, the Application Subcommittee voted to approve partial funding for two projects, DISC2-11192 and DISC2-11109 and to recommend, at the next full Board meeting in October, that the projects get the remainder of the funds needed to complete their research.
The successful applications are:
CIRM COMMITTED FUNDING
Genetically Modified Hematopoietic Stem Cells for the
Treatment of Danon Disease
U.C San Diego
Preclinical Development of An HSC-Engineered Off-
The-Shelf iNKT Cell Therapy for Cancer
U.C. Los Angeles
Non-viral reprogramming of the endogenous TCRα
locus to direct stem memory T cells against shared
neoantigens in malignant gliomas
U.C. San Francisco
Therapeutic immune tolerant human islet-like
organoids (HILOs) for Type 1 Diabetes
Chimeric Antigen Receptor-Engineered Stem/Memory
T Cells for the Treatment of Recurrent Ovarian Cancer
City of Hope
Develop iPSC-derived microglia to treat progranulin-
In need of an extra dose of inspiration? You might read a great book or listen to that podcast your friend recommended. You might even take a stroll along the beach. But I can do you one better: go to a conference poster session where young stem cell scientists describe their research.
That’s what I did last week at the City College of San Francisco’s (CCSF) Bioscience Symposium held at UC San Francisco’s Genentech Hall. It’s a day-long conference that showcases the work of CCSF Bioscience interns and gives them a chance to present the results of their research projects, network with their peers and researchers, hear panelists talk about careers in biotechnology and participate in practice job interviews.
CCSF’s CIRM Bridges Scholars (clockwise from top left): Vanessa Lynn Herrara, Viktoriia Volobuieva, Christopher Nosworthy and Sofiana E. Hamama.
CCSF’s CIRM Bridges Scholars (clockwise from top left): Seema Niddapu, Mark Koontz, Karolina Kaminska and Iris Avellano
Eight of the dozens of students in attendance at the Symposium are part of the CIRM-funded Bridges Stem Cell Internship program at CCSF. It’s one of 14 CIRM Bridges programs throughout the state that provides paid stem cell research internships to students at universities and colleges that don’t have major stem cell research programs. Each Bridges internship includes thorough hands-on training and education in stem cell research, and direct patient engagement and outreach activities that engage California’s diverse communities.
In the CCSF Bridges Program, directed by Dr. Carin Zimmerman, the students do a 9-month paid internship in top notch labs at UCSF, the Gladstone Institutes and Blood System Research Institute. As I walked from poster to poster and chatted with each Bridges scholar, their excitement and enthusiasm for carrying out stem cell research was plain to see. It left me with the feeling that the future of stem cell research is in good hands and, as I walked into the CIRM office the next day, I felt re-energized to tackle the Agency’s mission to accelerate stem cell treatment for patients with unmet medical needs. But don’t take my word for it, listen to the enthusiastic perspectives of Bridges scholars Mark Koontz and Iris Avellano in this short video.
With a clinical trial failure rate of 99% over the past 15 years or so, the path to a cure for Alzheimer’s disease is riddled with disappointment. In many cases, candidate therapies looked very promising in pre-clinical animal studies, only to flop when tested in people. Now, a CIRM-funded Nature Medicine study by researchers at the Gladstone Institutes sheds some light on a source of this discrepancy. And more importantly, the study points to a potential treatment strategy that can remove the hallmarks of Alzheimer’s in human brain cells.
For several decades, researchers have known the ApoE gene can influence the risk for an Alzheimer’s diagnosis in individuals 65 years and older. The gene comes in a few flavors with ApoE3 and ApoE4 differing in only one spot in their DNA sequences. Though nearly identical, the resulting ApoE3 and E4 proteins have very different shapes with differing function. In fact, people who inherit two copies of the ApoE4 gene have a twelve times higher risk for Alzheimer’s compared to those with the more common ApoE3.
To better understand what’s happening at the cellular level, Yadong Huang, PhD and his team at the Gladstone Institutes obtained skin samples from Alzheimer’s donors carrying two copies of the ApoE4 gene and healthy donors with two copies of ApoE3. The skin cells were reprogrammed into induced pluripotent stem cells (iPSCs) and then matured into nerve cells, or neurons.
Compared to ApoE3 cells, the researchers observed that the ApoE4 neurons accumulated higher levels of proteins called p-tau and amyloid beta, which are hallmarks of Alzheimer’s disease. Repeating this same experiment in iPSC-derived mouse neurons showed no difference in the production of amyloid beta levels between the ApoE3 and E4 neurons. This result points to the importance of studying human disease in human cells, as first author Chengzhong Wang, PhD, points out in a press release:
“There’s an important species difference in the effect of apoE4 on amyloid beta. Increased amyloid beta production is not seen in mouse neurons and could potentially explain some of the discrepancies between mice and humans regarding drug efficacy. This will be very important information for future drug development.”
Further experiments aimed to answer a long sought-after question: is it the absence of ApoE3 or the presence of ApoE4 that causes the damaging effects on neurons? Using gene-editing techniques, the team removed both ApoE forms from the donor-derived neurons. The resulting cells appeared healthy but when ApoE4 was added back in, Alzheimer’s-associated problems emerged. This finding points to the toxicity of ApoE4 to neurons.
With this new insight in hand, the team examined what would happen if they converted the ApoE4 form into the ApoE3 form. The team had previously designed molecules, they dubbed “structure correctors”, that physically interact with the ApoE4 protein and cause it to take on the shape of the ApoE3 form found in healthy individuals. When these correctors were added to the ApoE4 neurons, it brought back normal function to the cells.
Given that the structure corrector is a chemical compound that works in human brain cells, it’s tantalizing to think about its possible use as a novel Alzheimer’s drug. And you can bet Dr. Huang and his group are eagerly embarking on that new path.
Modern medicine often involves the development of a drug or treatment outside the body, which is then given to a patient to fix, improve or even prevent their condition. But what if you could regenerate or heal the body using the cells and tissue already inside a patient?
Scientists at the Gladstone Institutes are pursuing such a strategy for heart disease. In a CIRM-funded study published today in the journal Cell, the team identified four genes that can stimulate adult heart muscle cells, called cardiomyocytes, to divide and proliferate within the hearts of living mice. This discovery could be further developed as a strategy to repair cardiac tissue damage caused by heart disease and heart attacks.
Regenerating the Heart
Heart disease is the leading cause of death in the US and affects over 24 million people around the world. When patients experience a heart attack, blood flow is restricted to the heart, and parts of the heart muscle are damaged or die due to the lack of oxygen. The heart is unable to regenerate new healthy heart muscle, and instead, cardiac fibroblasts generate fibrous scar tissue to heal the injury. This scar tissue impairs the heart’s ability to pump blood, causing it to work harder and putting patients at risk for future heart failure.
Deepak Srivastava, President of the Gladstone Institutes and a senior investigator there, has dedicated his life’s research to finding new ways to regenerate heart tissue. Previously, his team developed methods to reprogram mouse and human cardiac fibroblasts into beating cardiomyocytes in hopes of one day restoring heart function in patients. The team is advancing this research with the help of a CIRM Discovery Stage research grant, which will aid them in developing a gene therapy product that delivers reprogramming factors into scar tissue cells to regenerate new heart muscle.
In this new study, Srivastava took a slightly different approach and attempted to coax cardiomyocytes, rather than cardiac fibroblasts, to divide and regenerate the heart. During development, fetal cardiomyocytes rapidly divide to create heart tissue. This regenerative ability is lost in adult cardiomyocytes, which are unable to divide because they’ve already exited the cell cycle (a series of phases that a cell goes through that ultimately results in its division).
Deepak Srivastava (left) and first author Tamer Mohamed (right). Photo credits: Diana Rothery.
Unlocking proliferative potential
Srivastava had a hunch that genes specifically involved in the cell division could be used to jump-start an adult cardiomyocyte’s re-entry into the cell cycle. After some research, they identified four genes (referred to as 4F) involved in controlling cell division. When these genes were turned on in adult cardiomyocytes, the cells started to divide and create new heart tissue.
This 4F strategy worked in mouse and rat cardiomyocytes and also was successful in stimulating cell division in 15%-20% of human cardiomyocytes. When they injected 4F into the hearts of mice that had suffered heart attacks, they observed an improvement in their heart function after three months and a reduction in the size of the scar tissue compared to mice that did not receive the injection.
The team was able to further refine their method by replacing two of the four genes with chemical inhibitors that had similar functions. Throughout the process, the team did not observe the development of heart tumors caused by the 4F treatment. They attributed this fact to the short-term expression of 4F in the cardiomyocytes. However, Srivastava expressed caution towards using this method in a Gladstone news release:
“In human organs, the delivery of genes would have to be controlled carefully, since excessive or unwanted cell division could cause tumors.”
First stop heart, next stop …
This study suggests that it’s possible to regenerate our tissues and organs from within by triggering adult cells to re-enter the cell cycle. While more research is needed to ensure this method is safe and worthy of clinical development, it could lead to a regenerative treatment strategy for heart failure.
Srivastava will continue to unravel the secrets to the proliferative potential of cardiomyocytes but predicts that other labs will pursue similar methods to test the regenerative potential of adult cells in other tissues and organs.
“Heart cells were particularly challenging because when they exit the cell cycle after birth, their state is really locked down—which might explain why we don’t get heart tumors. Now that we know our method is successful with this difficult cell type, we think it could be used to unlock other cells’ potential to divide, including nerve cells, pancreatic cells, hair cells in the ear, and retinal cells.”
(Credit: Jon Enriquez/Mann Lab/Columbia’s Zuckerman Institute).
This rainbow sherbet-colored scientific art is a microscopy image of a fruit fly nervous system in which brain cells were randomly labeled with different colors. It was a figure in a Neuron study published this week showing how cells derived from the same stem cells can go down very different developmental paths but then later are “reunited” to carry out key functions, such as in this case, the nervous system control of leg movements.
Many animal models of Parkinson’s disease are created by mutating specific genes to cause symptoms that mimic this incurable, neurodegenerative disorder. But, by far, most cases of Parkinson’s are idiopathic, a fancy term for spontaneous with no known genetic cause. So, researchers at the Buck Institute took another approach: they generated a mouse model of Parkinson’s disease using the pesticide, paraquat, exposure to which is known to increase the risk of the idiopathic form of Parkinson’s.
Their CIRM-funded study in Cell Reports showed that exposure to paraquat leads to cell senescence – in which cells shut down and stop dividing – particularly in astrocytes, brain cells that support the function of nerve cells. Ridding the mice of these astrocytes relieved some of the Parkinson’s like symptoms. What makes these results so intriguing is the team’s analysis of post-mortem brains from Parkinson’s patients also showed the hallmarks of increased senescence in astrocytes. Perhaps, therapeutic approaches that can remove senescent cells may yield novel Parkinson’s treatments.
Another CIRM-funded study published this week in Nature Neuroscience may also help pave the way to new treatment strategies for neurologic disorders like Parkinson’s disease. A team at Sanford Burnham Prebys Medical Discovery Institute (SBP) discovered a novel gene regulation system that brain stem cells use to maintain their ability to self-renew.
The study centers around messenger RNA, a molecular courier that transcribes a gene’s DNA code and carries it off to be translated into a protein. The team found that the removal of a chemical tag on mRNA inside mouse brain stem cells caused them to lose their stem cell properties. Instead, too many cells specialized into mature brain cells leading to abnormal brain development in animal studies. Team lead Jing Crystal Zhao, explained how this finding is important for future therapeutic development:
“As NSCs are increasingly explored as a cell replacement therapy for neurological disorders, understanding the basic biology of NSCs–including how they self-renew–is essential to harnessing control of their in vivo functions in the brain.”
Our regular readers are most likely familiar with both CRISPR gene editing and induced pluripotent stem cell (iPSC) technologies. But, in case you missed it late last week, a Cell Stem Cell study out of Sheng Ding’s lab at the Gladstone Institutes, for the first time, combined the two by using CRISPR to make iPSCs. The study got a lot of attention including a review by Paul Knoepfler in his blog The Niche. Check it out for more details!
For eight long years, researchers who were trying to develop a stem cell-based therapy for Parkinson’s disease – an incurable movement disorder marked by uncontrollable shaking, body stiffness and difficulty walking – found themselves lost in the proverbial wilderness. In initial studies, rodent stem cells were successfully coaxed to specialize into dopamine-producing nerve cells, the type that are lost in Parkinson’s disease. And further animal studies showed these cells could treat Parkinson’s like symptoms when transplanted into the brain.
Lorenz Studer, MD Photo Credit: Sloan Kettering
But when identical recipes were used to make human stem cell-derived dopamine nerve cells the same animal experiments didn’t work. By examining the normal developmental biology of dopamine neurons much more closely, Lorenz Studer cracked the case in 2011. Now seven years later, Dr. Studer, director of the Center for Stem Cell Biology at the Memorial-Sloan Kettering Cancer Center, and his team are on the verge of beginning clinical trials to test their Parkinson’s cell therapy in patients
It’s for these bottleneck-busting contributions to the stem cell field that Dr. Studer was awarded the Gladstone Institutes’ 2017 Ogawa-Yamanaka Stem Cell Prize. Now in its third year, the prize was founded by philanthropists Hiro and Betty Ogawa along with Shinya Yamanaka, Gladstone researcher and director of the Center for iPS Cell Research and Application at Kyoto University, and is meant to inspire and celebrate discoveries that build upon Yamanaka’s Nobel prize winning discovery of induced pluripotent stem cells (iPSCs).
(L to R) Shinya Yamanaka, Andrew Ogawa, Deepak Srivastava present Lorenz Studer the 2017 Ogawa-Yamanaka Stem Cell Prize at Gladstone Institutes. Photo Credit: Todd Dubnicoff/CIRM
Studer was honored at the Gladstone in November and presented the Ogawa-Yamanka Stem Cell Prize Lecture. He was kind enough to sit down with me for a brief video interview (watch it below) a few minutes before he took the stage. He touched upon his Parkinson’s disease research as well as newer work related to hirschsprung disease, a dangerous intestinal disorder often diagnosed at birth that is caused by the loss of nerve cells in the gut. Using human embryonic stem cells and iPSCs derived from hirschsprung patients, Studer’s team has worked out the methods for making the gut nerve cells that are lost in the disease. This accomplishment has allowed his lab to better understand the disease and to make solid progress toward a stem cell-based therapy.
His groundbreaking work has also opened up the gates for other Parkinson’s researchers to make important insights in the field. In fact, CIRM is funding several interesting early stage projects aimed at moving therapy development forward: