The Scripps Research Institute

Stem Cell Agency Invests in New Immunotherapy Approach to HIV, Plus Promising Projects Targeting Blindness and Leukemia

/ Kevin McCormack / 8 Comments

HIV AIDS

While we have made great progress in developing therapies that control the AIDS virus, HIV/AIDS remains a chronic condition and HIV medicines themselves can give rise to a new set of medical issues. That’s why the Board of the California Institute for Regenerative Medicine (CIRM) has awarded $3.8 million to a team from City of Hope to develop an HIV immunotherapy.

The City of Hope team, led by Xiuli Wang, is developing a chimeric antigen receptor T cell or CAR-T that will enable them to target and kill HIV Infection. These CAR-T cells are designed to respond to a vaccine to expand on demand to battle residual HIV as required.

Jeff Sheehy

CIRM Board member Jeff Sheehy

Jeff Sheehy, a CIRM Board member and patient advocate for HIV/AIDS, says there is a real need for a new approach.

“With 37 million people worldwide living with HIV, including one million Americans, a single treatment that cures is desperately needed.  An exciting feature of this approach is the way it is combined with the cytomegalovirus (CMV) vaccine. Making CAR T therapies safer and more efficient would not only help produce a new HIV treatment but would help with CAR T cancer therapies and could facilitate CAR T therapies for other diseases.”

This is a late stage pre-clinical program with a goal of developing the cell therapy and getting the data needed to apply to the Food and Drug Administration (FDA) for permission to start a clinical trial.

The Board also approved three projects under its Translation Research Program, this is promising research that is building on basic scientific studies to hopefully create new therapies.

  • $5.068 million to University of California at Los Angeles’ Steven Schwartz to use a patient’s own adult cells to develop a treatment for diseases of the retina that can lead to blindness
  • $4.17 million to Karin Gaensler at the University of California at San Francisco to use a leukemia patient’s own cells to develop a vaccine that will stimulate their immune system to attack and destroy leukemia stem cells
  • Almost $4.24 million to Stanford’s Ted Leng to develop an off-the-shelf treatment for age-related macular degeneration (AMD), the leading cause of vision loss in the elderly.

The Board also approved funding for seven projects in the 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.

Application Title Institution CIRM Committed Funding
DISC2-10979 Universal Pluripotent Liver Failure Therapy (UPLiFT)

 

 Children’s Hospital of Los Angeles $1,297,512

 
DISC2-11105 Pluripotent stem cell-derived bladder epithelial progenitors for definitive cell replacement therapy of bladder cancer

 

 Stanford $1,415,016
DISC2-10973 Small Molecule Proteostasis Regulators to Treat Photoreceptor Diseases

 

 U.C. San Diego $1,160,648
DISC2-11070 Drug Development for Autism Spectrum Disorder Using Human Patient iPSCs

 

 Scripps $1,827,576
DISC2-11183 A screen for drugs to protect against chemotherapy-induced hearing loss, using sensory hair cells derived by direct lineage reprogramming from hiPSCs

 

 University of Southern California $833,971
DISC2-11199 Modulation of the Wnt pathway to restore inner ear function

 

 Stanford $1,394,870
DISC2-11109 Regenerative Thymic Tissues as Curative Cell Therapy for Patients with 22q11 Deletion Syndrome

 

 Stanford $1,415,016

Finally, the Board approved the Agency’s 2019 research budget. Given CIRM’s new partnership with the National Heart, Lung, Blood Institute (NHLBI) to accelerate promising therapies that could help people with Sickle Cell Disease (SCD) the Agency is proposing to set aside $30 million in funding for this program.

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Congresswoman Barbara Lee (D-CA 13th District)

Congresswoman Barbara Lee (D-CA 13th DIstrict)

“I am deeply grateful for organizations like CIRM and NHLBI that do vital work every day to help people struggling with Sickle Cell Disease,” said Congresswoman Barbara Lee (D-CA 13th District). “As a member of the House Appropriations Subcommittee on Labor, Health and Human Services, and Education, I know well the importance of this work. This innovative partnership between CIRM and NHLBI is an encouraging sign of progress, and I applaud both organizations for their tireless work to cure Sickle Cell Disease.”

Under the agreement CIRM and the NHLBI will coordinate efforts to identify and co-fund promising therapies targeting SCD.  Programs that are ready to start an IND-enabling or clinical trial project for sickle cell can apply to CIRM for funding from both agencies. CIRM will share application information with the NHLBI and CIRM’s Grants Working Group (GWG) – an independent panel of experts which reviews the scientific merits of applications – will review the applications and make recommendations. The NHLBI will then quickly decide if it wants to partner with CIRM on co-funding the project and if the CIRM governing Board approves the project for funding, the two organizations will agree on a cost-sharing partnership for the clinical trial. CIRM will then set the milestones and manage the single CIRM award and all monitoring of the project.

“This is an extraordinary opportunity to create a first-of-its-kind partnership with the NHLBI to accelerate the development of curative cell and gene treatments for patients suffering with Sickle Cell Disease” says Maria T. Millan, MD, President & CEO of CIRM. “This allows us to multiply the impact each dollar has to find relief for children and adults who battle with this life-threatening, disabling condition that results in a dramatically shortened lifespan.  We are pleased to be able to leverage CIRM’s acceleration model, expertise and infrastructure to partner with the NHLBI to find a cure for this condition that afflicts 100,000 Americans and millions around the globe.”

The budget for 2019 is:

Program type 2019
CLIN1 & 2

CLIN1& 2 Sickle Cell Disease

 $93 million

$30 million
TRANSLATIONAL $20 million
DISCOVER $0
EDUCATION $600K

 

 

Using biological “codes” to generate neurons in a dish

/ Pallavi Penumetcha / Leave a comment

BrainWavesInvestigators at the Scripps Research Institute are making brain waves in the field of neuroscience. Until now, neuroscience research has largely relied on a variety of animal models to understand the complexities of various brain or neuronal diseases. While beneficial for many reasons, animal models do not always allow scientists to understand the precise mechanism of neuronal dysfunction, and studies done in animals can often be difficult to translate to humans. The work done by Kristin Baldwin’s group, however, is revolutionizing this field by trying to re-create this complexity in a dish.

One of the primary hurdles that scientists have had to overcome in studying neuronal diseases, is the impressive diversity of neuronal cell types that exist. The exact number of neuronal subtypes is unknown, but scientists estimate the number to be in the hundreds.

While neurons have many similarities, such as the ability to receive and send information via chemical cues, they are also distinctly specialized. For example, some neurons are involved in sensing the external environment, whereas others may be involved in helping our muscles move. Effective medical treatment for neuronal diseases is contingent on scientists being able to understand how and why specific neuronal subtypes do not function properly.

In a study in the journal Nature, partially funded by CIRM, the scientists used pairs of transcription factors (proteins that affect gene expression and cell identity), to turn skin stem cells into neurons. These cells both physically looked like neurons and exhibited characteristic neuronal properties, such as action potential generation (the ability to conduct electrical impulses). Surprisingly, the team also found that they were able to generate neurons that had unique and specialized features based on the transcription factors pairs used.

The ability to create neuronal diversity using this method indicates that this protocol could be used to recapitulate neuronal diversity outside of the body. In a press release, Dr. Baldwin states:

KristinBaldwin

Kristin Baldwin, PhD

“Now we can be better genome detectives. Building up a database of these codes [transcription factors] and the types of neurons they produce can help us directly link genomic studies of human brain disease to a molecular understanding of what goes wrong with neurons, which is the key to finding and targeting treatments.”

These findings provide an exciting and promising tool to more effectively study the complexities of neuronal disease. The investigators of this study have made their results available on a free platform called BioGPS in the hopes that multiple labs will delve into the wealth of information they have opened up. Hopefully, this system will lead to more rapid drug discovery for disease like autism and Alzheimer’s

Celebrating Exciting CIRM-Funded Discovery Research on World Parkinson’s Day

/ Karen Ring / Leave a comment

April 11th is World Parkinson’s Disease Awareness Day. To mark the occasion, we’re featuring the work of CIRM-funded researchers who are pursuing new, promising ideas to treat patients with this debilitating neurodegenerative disease.

Birgitt Schuele, Parkinson’s Institute

CIRM Grant: Quest Award – Discovery Stage Research

Research: Birgitt and her team at the Parkinson’s Institute in Sunnyvale, California, are using CRISPR gene editing technology to reduce the levels of a toxic protein called alpha synuclein, which builds up in the dopaminergic brain cells affected by Parkinson’s disease.

Birgitt Schuele

“My hope is that I can contribute to stopping disease progression in Parkinson’s. If we can develop a drug that can get rid of accumulated protein in someone’s brain that should stop the cells from dying. If someone has early onset PD and a slight tremor and minor walking problems, stopping the disease and having a low dose of dopamine therapy to control symptoms is almost a cure.”

Parkinson’s disease in a dish. Dopaminergic neurons made from Parkinson’s patient induced pluripotent stem cells. (Image credit: Birgitt Schuele)

Jeanne Loring, Scripps Research Institute

CIRM Grant: Quest Award – Discovery Stage Research

Research: Jeanne Loring and her team at the Scripps Research Institute in La Jolla, California, are deriving dopaminergic neurons from the iPSCs of Parkinson’s patients. Their goal is to develop a personalized, stem cell-based therapy for PD.

Jeanne Loring

“We are working toward a patient-specific neuron replacement therapy for Parkinson’s disease.  By the time PD is diagnosed, people have lost more than half of their dopamine neurons in a specific part of the brain, and loss continues over time.  No drug can stop the loss or restore the neurons’ function, so the best possible option for long term relief of symptoms is to replace the dopamine neurons that have died.  We do this by making induced pluripotent stem cells from individual PD patients and turning them into the exact type of dopamine neuron that has been lost.  By transplanting a patient’s own cells, we will not need to use potentially dangerous immunosuppressive drugs.  We plan to begin treating patients in a year to two years, after we are granted FDA approval for the clinical therapy.”

Skin cells from a Parkinson’s patient (left) were reprogrammed into induced pluripotent stem cells (center) that were matured into dopaminergic neurons (right) to model Parkinson’s disease. (Image credit: Jeanne Loring)

Justin Cooper-White, Scaled BioLabs Inc.

CIRM Grant: Quest Award – Discovery Stage Research

Research: Justin Cooper-White and his team at Scaled Biolabs in San Francisco are developing a tool that will make clinical-grade dopaminergic neurons from the iPSCs of PD patients in a rapid and cost-effective manner.

Justin Cooper-White

“Treating Parkinson’s disease with iPSC-derived dopaminergic neuron transplantation has a strong scientific and clinical rationale. Even the best protocols are long and complex and generally have highly variable quality and yield of dopaminergic neurons. Scaled Biolabs has developed a technology platform based on high throughput microfluidics, automation, and deep data which can optimize and simplify the road from iPSC to dopaminergic neuron, making it more efficient and allowing a rapid transition to GMP-grade derivation of these cells.  In our first 6 months of CIRM-funded work, we believe we have already accelerated and simplified the production of a key intermediate progenitor population, increasing the purity from the currently reported 40-60% to more than 90%. The ultimate goal of this work is to get dopaminergic neurons to the clinic in a robust and economical manner and accelerate treatment for Parkinson’s patients.”

High throughput differentiation of dopaminergic neuron progenitors in  microbioreactor chambers in Scaled Biolabs’ cell optimization platform. Different chambers receive different differentiation factors, so that optimal treatments for conversion to dual-positive cells can be determined (blue: nuclei, red: FOXA2, green: LMX1A).

Xinnan Wang, Stanford University

CIRM Grant: Basic Biology V

Research: Xinnan Wang and her team at Stanford University are studying the role of mitochondrial dysfunction in the brain cells affected in Parkinson’s disease.

Xinnan Wang

“Mitochondria are a cell’s power plants that provide almost all the energy a cell needs. When these cellular power plants are damaged by stressful factors present in aging neurons, they release toxins (reactive oxygen species) to the rest of the neuron that can cause neuronal cell death (neurodegeneration).  We hypothesized that in Parkinson’s mutant neurons, mitochondrial quality control is impaired thereby leading to neurodegeneration. We aimed to test this hypothesis using neurons directly derived from Parkinson’s patients (induced pluripotent stem cell-derived neurons).”

Dopaminergic neurons derived from human iPSCs shown in green, yellow and red. (Image credit: Atossa Shaltouki, Stanford)

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Scientists find switch that targets immunotherapies to solid tumors

/ Karen Ring / Leave a comment

Cancer immunotherapies harness the power of the patient’s own immune system to fight cancer. One type of immunotherapy, called adoptive T cell therapy, uses immune cells called CD8+ Killer T cells to target and destroy tumors. These T cells are made in the spleen and lymph nodes and they can migrate to different locations in the body through a part of our circulatory system known as the lymphatic system.

CD8+ T cells can also leave the circulation and travel into the body’s tissues to fight infection and cancer. Scientists from the Scripps Research Institute and UC San Diego are interested in learning how these killer T cells do just that in hopes of developing better immunotherapies that can specifically target solid tumors.

In a study published last week in the journal Nature, the teams discovered that a gene called Runx3 acts as a switch that programs CD8+ T cells to set up shop within tissues outside of the circulatory system, giving them access to solid tumors.

“Runx3 works on chromosomes inside killer T cells to program genes in a way that enables the T cells to accumulate in a solid tumor,” said Matthew Pipkin, co-senior author and Associate Professor at The Scripps Research Institute.

Study authors Adam Getzler, Dapeng Wang and Matthew Pipkin of The Scripps Research Institute collaborated with scientists at the University of California, San Diego.

They discovered Runx3 by comparing what genes were expressed in CD8+ T cells found in the lymphatic system to CD8+ T cells that were found in tissues outside of the circulation. They then screened thousands of potential factors for their ability to influence CD8+ T cells to infiltrate solid tumors.

“We found a distinct pattern,” Pipkin said. “The screens showed that Runx3 is one at the top of a list of regulators essential for T cells to reside in non-lymphoid tissues.”

The team then set out to prove that Runx3 was a key factor in getting CD8+ T cells to localize at the site of solid tumors. To do this, they took T cells that either overexpressed Runx3 or did not express Runx3 in these cells. The T cells were then transplanted into mice with melanoma through a process known as adoptive cell transfer. Overexpression of Runx3 in T cells not only reduced tumor size but also extended lifespan in the mice. On the other hand, removing Runx3 expression had a negative impact on their survival rate.

This research, which was supported in part by CIRM funding, offers a new strategy for developing better cancer immunotherapies for solid tumors.

Pipkin concluded in a Scripps Research Institutes News Release,

“Knowing that modulating Runx3 activity in T cells influences their ability to reside in solid tumors opens new opportunities for improving cancer immunotherapy. We could probably use Runx3 to reprogram adoptively transferred cells to help drive them to amass in solid tumors.”

CIRM-funded scientists discover a new way to make stem cells using antibodies

/ Karen Ring / 1 Comment

Just as learning a new skill takes time to hone, scientific discoveries take time to perfect. Such is the case with induced pluripotent stem cells (iPSCs), the Nobel Prize winning technology that reprograms mature adult cells back into a pluripotent stem cell state. iPSCs are a powerful tool because they can develop into any cell found in the body. Scientists use iPSCs to model diseases in a dish, screen for new drugs, and to develop stem cell-based therapies for patients.

iPSCs grown in a cell culture dish.

The original iPSC technology, discovered by Dr. Shinya Yamanaka in 2006, requires viral delivery of four transcription factor genes, Oct4, Sox2, Klf4, and c-Myc, into the nucleus of an adult cell. These genes are inserted into the genome where they are activated to churn out their respective proteins. The combined expression of these four factors (OSKM) turns off the genetic programming of an adult cell and turns on the programming for a pluripotent stem cell.

The technology is pretty neat and allows scientists to make iPSCs from patients using a variety of different tissue sources including skin, blood, and even urine. However, there is a catch. Inserting reprogramming genes into a cell’s genome can be disruptive if the reprogramming genes fail to switch off or can cause cancer if nefarious oncogenes are turned on.

In response to this concern, scientists are developing alternative methods for making iPSCs using non-invasive methods. A CIRM-funded team from The Scripps Research Institute (TSRI) published such a study yesterday in the journal Nature Biotechnology.

Led by senior author and CIRM grantee Dr. Kristin Baldwin, the TSRI team screened a large library of antibodies – proteins that recognize and bind to specific molecules – to identify ones that could substitute for the OSKM reprogramming factors. The hope was that some of these antibodies would bind to proteins on the surface of cells and turn on a molecular signaling cascade from the outside that would turn on the appropriate reprogramming genes from the inside of the cell.

The scientists screened over 100 million antibodies and found ones that could replace three of the four reprogramming factors (Oct4, Sox2, and c-Myc) when reprogramming mouse skin cells into iPSCs. They were unable to find an antibody to replace Klf4 in the current study but have it on their to-do list for future studies.

Dr. Baldwin explained how her team’s findings improve upon previous reprogramming methods in a TSRI news release,

Kristen Baldwin

“This result suggests that ultimately we might be able to make IPSCs without putting anything in the cell nucleus, which potentially means that these stem cells will have fewer mutations and overall better properties.”

 

Other groups have published other non-invasive iPSC reprogramming methods using cocktails of chemicals, proteins or microRNAs in place of virally delivering genes to make iPSCs. However, Baldwin’s study is the first (to our knowledge) to use antibodies to achieve this feat.

An added benefit to antibody reprogramming is that the team was able to learn more about the signaling pathways that were naturally activated by the iPSC reprogramming antibodies.

“The scientists found that one of the Sox2-replacing antibodies binds to a protein on the cell membrane called Basp1. This binding event blocks Basp1’s normal activity and thus removes the restraints on WT1, a transcription factor protein that works in the cell nucleus. WT1, unleashed, then alters the activity of multiple genes, ultimately including Sox2’s, to promote the stem cell state using a different order of events than when using the original reprogramming factors.”

iPSCs made by antibody reprogramming could address some of the long-standing issues associated with more traditional reprogramming methods and could offer further insights into the complex signaling required to turn adult cells back into a pluripotent state. Baldwin and her team are now on the hunt for antibodies that will reprogram human (rather than mouse) cells into iPSCs. Stay tuned!

Stories that caught our eye: stem cell transplants help put MS in remission; unlocking the cause of autism; and a day to discover what stem cells are all about

/ Kevin McCormack / Leave a comment
multiple-sclerosis

Motor neurons

Stem cell transplants help put MS in remission: A combination of high dose immunosuppressive therapy and transplant of a person’s own blood stem cells seems to be a powerful tool in helping people with relapsing-remitting multiple sclerosis (RRMS) go into sustained remission.

Multiple sclerosis (MS) is an autoimmune disorder where the body’s own immune system attacks the brain and spinal cord, causing a wide variety of symptoms including overwhelming fatigue, blurred vision and mobility problems. RRMS is the most common form of MS, affecting up to 85 percent of people, and is characterized by attacks followed by periods of remission.

The HALT-MS trial, which was sponsored by the National Institute of Allergy and Infectious Diseases (NIAID), took the patient’s own blood stem cells, gave the individual chemotherapy to deplete their immune system, then returned the blood stem cells to the patient. The stem cells created a new blood supply and seemed to help repair the immune system.

Five years after the treatment, most of the patients were still in remission, despite not taking any medications for MS. Some people even recovered some mobility or other capabilities that they had lost due to the disease.

In a news release, Dr. Anthony Fauci, Director of NIAID, said anything that holds the disease at bay and helps people avoid taking medications is important:

“These extended findings suggest that one-time treatment with HDIT/HCT may be substantially more effective than long-term treatment with the best available medications for people with a certain type of MS. These encouraging results support the development of a large, randomized trial to directly compare HDIT/HCT to standard of care for this often-debilitating disease.”

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Scripps Research Institute

Using stem cells to model brain development disorders. (Karen Ring) CIRM-funded scientists from the Scripps Research Institute are interested in understanding how the brain develops and what goes wrong to cause intellectual disabilities like Fragile X syndrome, a genetic disease that is a common cause of autism spectrum disorder.

Because studying developmental disorders in humans is very difficult, the Scripps team turned to stem cell models for answers. This week, in the journal Brain, they published a breakthrough in our understanding of the early stages of brain development. They took induced pluripotent stem cells (iPSCs), made from cells from Fragile X syndrome patients, and turned these cells into brain cells called neurons in a cell culture dish.

They noticed an obvious difference between Fragile X patient iPSCs and healthy iPSCs: the patient stem cells took longer to develop into neurons, a result that suggests a similar delay in fetal brain development. The neurons from Fragile X patients also had difficulty forming synaptic connections, which are bridges that allow for information to pass from one neuron to another.

Scripps Research professor Jeanne Loring said that their findings could help to identify new drug therapies to treat Fragile X syndrome. She explained in a press release;

“We’re the first to see that these changes happen very early in brain development. This may be the only way we’ll be able to identify possible drug treatments to minimize the effects of the disorder.”

Looking ahead, Loring and her team will apply their stem cell model to other developmental diseases. She said, “Now we have the tools to ask the questions to advance people’s health.”

A Day to Discover What Stem Cells Are All about.  (Karen Ring) Everyone is familiar with the word stem cells, but do they really know what these cells are and what they are capable of? Scientists are finding creative ways to educate the public and students about the power of stem cells and stem cell research. A great example is the University of Southern California (USC), which is hosting a Stem Cell Day of Discovery to educate middle and high school students and their families about stem cell research.

The event is this Saturday at the USC Health Sciences Campus and will feature science talks, lab tours, hands-on experiments, stem cell lab video games, and a resource fair. It’s a wonderful opportunity for families to engage in science and also to expose young students to science in a fun and engaging way.

Interest in Stem Cell Day has been so high that the event has already sold out. But don’t worry, there will be another stem cell day next year. And for those of you who don’t live in Southern California, mark your calendars for the 2017 Stem Cell Awareness Day on Wednesday, October 11th. There will be stem cell education events all over California and in other parts of the country during that week in honor of this important day.

 

 

A TWIST in mesenchymal stem cell trials: protein predicts therapy’s potential

/ Todd Dubnicoff / Leave a comment

Mesenchymal stem cells are adult stem cells with the potential to specialize into a somewhat limited number of cell types – those responsible for making fat, bone and cartilage. But MSCs are also known for their anti-inflammatory properties which are carried out via the release of protein factors.  This ability to dampen the immune system makes the MSC an extremely attractive source material for cell therapies. In fact, there are over 500  mesenchymal stem cell-based clinical trials testing treatments for diseases that target a wide range of tissues including spinal cord injury, diabetes, multiple sclerosis, respiratory disorders and graft versus host disease, just to name a few.

Human_MSCs_4x_0

Human mesenchymal stem cells grown in a single layer on the bottom of a flask; 4x magnification Image source: EuroStemCell

 MSCs and the Variability Problem
While some MSC-based human trials have had promising results in patients, other studies haven’t been as successful. A key culprit of these mixed results is the lack of standardization on what exactly is a MSC. It’s well documented that preparations of MSC vary significantly from one patient to the next. Even the composition of MSCs from one patient is far from a pure population of cells. And few of the cell surface markers used to define MSCs provide a measure of the cells’ function. This is a real problem for demonstrating the effectiveness and the marketability of MSC-based cell therapies which rely on the delivery of cell product with a consistent, well-defined composition and functional activity.

Help is now on the way based on research reported this week in EBioMedicine by a research team led by Professor Donald Phinney at the Florida campus of The Scripps Research Institute. In the study, the team found that the amount of TWIST1, a protein that regulates gene activity, in a given batch of MSCs could reliably predict the therapeutic effectiveness of those cells.

Meet TWIST1: predictor of a MSC therapy’s potential
They set their sights on TWIST1 because previous research described its important role in driving a MSC fate during human development. The team examined the natural variability of TWIST1 levels in human MSCs from several donors. They showed that lower levels of TWIST1 correlated to MSCs with stronger anti-inflammatory properties. Higher levels of TWIST1, on the other hand, were consistent with MSCs that induced angiogenesis, or blood vessel growth, another known ability of this versatile cell type. In another set of experiments, TWIST1 production was silenced using genetic tools. As predicted by the earlier results, these MSCs showed increased anti-inflammatory properties.

Move over Ritcher, Say Hello to the CLIP Scale

CLIPscale

The Clinical Indication Prediction (CLIP) scale. Image: Boregowda et al. EBioMedicine, Volume 4 , 62-73

Putting this data together, the team devised a scale they call Clinical Indication Prediction, or CLIP for short. The scale gives a clinical researcher an indication of the therapeutic potential of a given batch of donor MSCs based on the TWIST1 protein levels. This information could have a major impact on a clinical trial’s fate. Depending on the goal of a MSC-based cell therapy, a clinical team could set themselves up for failure before the trial even gets underway if they don’t take TWIST1 levels into account. First author Siddaraju V. Boregowda explains this scenario in a press release:

boregowda_siddaraju copy

Siddaraju V. Boregowda

“There are a number of clinical trials testing mesenchymal stem cells to treat arthritis. Since angiogenesis is a key part of the disease process, stem cells with high levels of TWIST1 (indicating they are more angiogenic) would not be beneficial. These cells might be helpful instead for indications such as peripheral vascular disease where new vascularization is beneficial. The proposed CLIP scale accurately predicts these indications and contra-indications.”

We’ll be keeping our eye on this exciting discovery to see if CLIP becomes an integral step in developing MSC-based cell therapies. If it pans out, the CLIP scale could help accelerate the development of new therapies by providing scientists with more clarity and confidence around classifying the identity of a MSC cell product. Stay tuned!

Cell survival strategy gives mesenchymal stem cells their “paramedic” properties

/ Todd Dubnicoff / 3 Comments
Electron micrograph of a human mesenchymal stem cells (Credit: Robert M. Hunt)

Electron micrograph of a human mesenchymal stem cells (Image credit: Robert M. Hunt)

A cell for all therapies
Type “mesenchymal stem cells” into the federal online database of registered clinical trials, and you’ll get a sprawling list of 527 trials testing treatments for diabetes, multiple sclerosis as well as diseases of the kidney, lung, and heart, to name just a few. Mesenchymal stem cells (MSCs) have the capacity to specialize into bone, cartilage, muscle and fat cells but their popularity as a therapeutic agent mostly comes from their ability to reduce inflammation and to help repair tissues.

MSCs may be great tools for scientists to fight disease, but what is it about their natural function that make MSCs – as UC Davis researcher Jan Nolta likes to calls them – the body’s “paramedics”? A fascinating study reported yesterday in Nature Communications by scientists at the Florida campus of The Scripps Research Institute (TSRI) and the University of Pittsburgh suggest that it’s a trait the cells gain as a result of their complex cell survival mechanisms.

The TSRI team came to this conclusion by studying how MSCs respond to oxygen-related stress. MSCs reside in the bone marrow where they help maintain and regulate blood stem cells. The bone marrow is naturally a hypoxic, or low oxygen, environment. Growing MSCs in the lab at oxygen levels found in the air we breathe are much higher than what is found in the marrow. This creates oxidative stress in which the excess oxygen leads to unwanted chemical reactions which disrupt a cell’s molecules.

One cell’s trash is another’s treasure
One result of this oxidative stress is damage to the MSCs’ mitochondria, structures responsible for generating the energy needs of a cell. The team found that MSCs package the faulty mitochondria into sacs, or vesicles, which travel to the cell surface to be dumped out of the cell. At this point, another resident of the bone marrow comes into the picture: the macrophage. Previous research has shown that macrophages and MSCs work closely together to maintain the health of the blood stem cells in the bone marrow.

Screen Shot 2015-11-04 at 9.58.48 AM

White arrow shows vesicles (red) carrying mitochondra (green) to the surface of the MSC  and being ingested by a macrophage (round shape in lower half) – (From Fig 2 Nat Commun. 2015 Oct 7;6:8472)

In a high oxygen stress environment, the team observed that MSCs can recruit macrophages to engulf the damaged mitochondria-containing vesicles and repurpose them for their own use. In fact, the researchers measured improved energy production in the macrophages after ingesting the MSCs’ mitochondria. Blocking the transfer of the damaged mitochondria from MSCs to macrophages caused the MSCs to die, confirming that this off-loading of mitochondria to macrophages is critical for MSC survival.

Evolving tricks for cell survival
Macrophages (macro=big; phages=eaters), key players of the immune system and the inflammation response, also rid the body of invading bacteria or damaged cells by devouring them. To avoid being swallowed up by the macrophage while donating its mitochondria, the stressed MSCs have another trick up their sleeve. The research team identified the release of other vesicles from the MSCs that contain molecules called microRNAs which stimulate anti-inflammatory properties in the macrophages. This prevented the macrophages from attacking and eating the MSCs.

And there you have it: as a result of relying on macrophages to survive stressful environments, MSCs appear to have evolved anti-inflammatory activities that turn out to be a handy tool for numerous ongoing and future cell therapy trials.

In a TSRI press release picked up by Newswise, professor Donald Phinney co-leader of study points out the groundbreaking aspect of the study:

Donald G. Phinney

Donald Phinney (photo: TSRI)

“This is the first time anyone has shown how mesenchymal stem cells provide for their own survival by recruiting and then suppressing normal macrophage activity.”

 

 

Goodnight, Stem Cells: How Well Rested Cells Keep Us Healthy

/ Todd Dubnicoff / Leave a comment

Plenty of studies show that a lack of sleep is nothing but bad news and can contribute to a whole host of health problems like heart disease, poor memory, high blood pressure and obesity.

HSCs_Sleeping_graphic100x100

Even stem cells need rest to stay healthy

In a sense, the same holds true for the stem cells in our body. In response to injury, adult stem cells go to work by dividing and specializing into the cells needed to heal specific tissues and organs. But they also need to rest for long-lasting health. Each cell division carries a risk of introducing DNA mutations—and with it, a risk for cancer. Too much cell division can also deplete the stem cell supply, crippling the healing process. So it’s just as important for the stem cells to assume an inactive, or quiescent, state to maintain their ability to mend the body. Blood stem cells for instance are mostly quiescent and only divide about every two months to renew their reserves.

Even though the importance of this balance is well documented, exactly how it’s achieved is not well understood; that is, until now. Earlier this week, a CIRM-funded research team from The Scripps Research Institute (TSRI) reported on the identification of an enzyme that’s key in controlling the work-rest balance in blood stem cells, also called hematopoietic stem cells (HSCs). Their study, published in the journal Blood, could point the way to drugs that treat anemias, blood cancers, and other blood disorders.

Previous studies in other cell types suggested that this key enzyme, called ItpkB, might play a role in promoting a rested state in HSCs. Senior author Karsten Sauer explained their reasoning for focusing on the enzyme in a press release:

“What made ItpkB an attractive protein to study is that it can dampen activating signaling in other cells. We hypothesized that ItpkB might do the same in HSCs to keep them at rest. Moreover, ItpkB is an enzyme whose function can be controlled by small molecules. This might facilitate drug development if our hypothesis were true.”

Senior author Karsten Sauer is an associate professor at The Scripps Research Institute.

Senior author Karsten Sauer is an associate professor at The Scripps Research Institute.

To test their hypothesis, the team studied HSCs in mice that completely lacked ItpkB. Sure enough, without ItpkB the HSCs got stuck in the “on” position and continually multiplied until the supply of HSCs stores in the bone marrow were exhausted. Without these stem cells, the mice could no longer produce red blood cells, which deliver oxygen to the body or white blood cells, which fight off infection. As a result the animals died due to severe anemia and bone marrow failure. Sauer used a great analogy to describe the result:

“It’s like a car—you need to hit the gas pedal to get some activity, but if you hit it too hard, you can crash into a wall. ItpkB is that spring that prevents you from pushing the pedal all the way through.”

With this new understanding of how balancing stem cell activation and deactivation works, Sauer and his team have their sights set on human therapies:

“If we can show that ItpkB also keeps human HSCs healthy, this could open avenues to target ItpkB to improve HSC function in bone marrow failure syndromes and immunodeficiencies or to increase the success rates of HSC transplantation therapies for leukemias and lymphomas.”

CIRM-Funded Scripps Team Replicates Pain in a Lab Dish; Seeks New Treatments for Chronic Sufferers

/ Todd Dubnicoff / 1 Comment

Pain hurts but it also protects. Thanks to nerve cells called sensory neurons, which weave their nerve fibers throughout our skin and other tissues, we are alerted to dangerous events like touching a hot plate or even to the sense of having a full bladder.

However, trauma such as a spinal cord injury or diseases like HIV and diabetes can damage sensory neurons and cause chronic pain that debilitates rather than protects those affected. Sadly, conventional pain treatments are usually not effective for the stinging, burning, tingling and numbness associated with this type of pain. Clearly, new innovations are needed.

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These induced sensory neurons could be useful in the testing of potential new therapies for pain, itch and related conditions. Credit: Baldwin Lab, The Scripps Research Institute

Last week, a CIRM-funded research team from The Scripps Research Institute, reported in Nature Neuroscience that they developed a technique, which induces human skin cells to transform into sensory neurons in a petri dish. Up until now, the field mostly relied on mouse studies due to the difficulty of collecting and growing human sensory neurons in the lab. This may explain the lack of success in clinical trials for treating chronic pain. As co-lead author Joel Blanchard, a PhD candidate in Kristin Baldwin’s laboratory, stated in the institute’s press release:

“Mouse models don’t represent the full diversity of the human response. [With these human sensory neurons] we can start to understand how individuals respond uniquely to pain, cold, itch and so on.”

Kevin Eade, research associate, and Joel Blanchard, graduate student, co-lead authors of the report Credit: Cindy Brauer, The Scripps Research Institute

Kevin Eade, research associate, and Joel Blanchard, graduate student, co-lead authors of the report. Credit: Cindy Brauer, The Scripps Research Institute

To generate the nerve cells, the Baldwin research team inserted, into human skin cells, a combination of genes known to produce proteins that are key controllers of sensory neuron function. The resulting cells had the appearance of sensory neurons and responded appropriately when exposed to heat in the form of the active ingredient in chili peppers as well as activating a cold response when exposed to menthol. Adding more confidence to these results, an independent research team from the Harvard Stem Cell Institute reported in the same Nature Neuroscience   issue and in a press release that they too had successfully generated human sensory neurons from skin cells.

This direct reprogramming of one cell type directly into another is a variant of the induced pluripotent stem cell (iPS) technique in which a cell, often skin, is first reprogrammed into an embryonic stem cell-like state and then coaxed to form into virtually any cell type of the body.

Now that the Baldwin lab has nailed down the recipe for making human sensory neurons, they now can seek out treatments to bring relief to chronic pain sufferers. Dr. Baldwin looks forward to this future work:

Kristin Baldwin, Associate Professor Department of Molecular and Cellular Neuroscience. Credit: The Scripps Research Institute

Kristin Baldwin
Associate Professor
Credit: The Scripps Research Institute

“This method is rapid, robust and scalable. Therefore we hope that these induced sensory neurons will allow our group and others to identify new compounds that block pain and itch and to better understand and treat neurodegenerative disease and spinal cord injury.”

Watch the short video below to hear from a pioneer of direct reprogramming of nerve cells, CIRM grantee Marius Wernig of Stanford University: