Funding opportunities

Optimizing human embryonic stem cell-derived neural stem/progenitor cells for stroke cell therapy

Funding Type: 
SEED Grant
Grant Number: 
RS1-00440
Funds requested: 
$658 125
Funding Recommendations: 
Not recommended
Grant approved: 
No
Public Abstract: 
Stroke has the highest annual incidence of any neurological disorder, it affects more people than Alzheimer’s disease, traumatic brain injury, epilepsy and Parkinson’s disease. In the United States, more than 750,000 individuals suffer from stroke every year. There are also approximately 5.4 million stroke survivors and about one-third of them are unable to care for themselves and almost 75% are impaired in some activities of their daily life. The estimated economic burden from stroke exceeds $56.8 billion per year in the United States. Due to the lack of effective therapies, these numbers will increase in the future. A recent study reports that the total cost of stroke from 2005-2050 in the US is projected to top $2 trillion dollars. Currently the only approved stroke treatment is a type of drug called a thrombolytic that breaks up the blood clot that caused the stroke. This drug is only effective within three hours after the clot forms and before severe brain damage can occur. However, if the stroke victim has a pre-existing medical condition, then thrombolytic treatment is too risky because it may cause excessive bleeding. Thus, only 1-4% of stroke patients are eligible and benefit from this treatment. Regenerative medicine is developing as a promising approach to repair diseased or injured brain through stem cell-based therapy. The rationale behind such an approach is to replace lost neural cells and allow or enhance the re-establishment of tissue function. Recent studies have demonstrated that multiple cell types can reverse behavioral deficits in animal models of stroke. However, unlike the human embryonic stem cells (hESCs), these cells are neither suitable for large-scale production nor for the appropriate quality assurance program needed to safely treat a sufficient patient population in multi-center clinical trials. In humans, the safety of the cell transplantation procedure has been demonstrated. The research proposed in this application aims to fill the void in therapeutic options by developing a suitable neural stem/progenitor cell lines (NSPCs) from the hESCs and by establishing parameters to safely transplant these neural cells into patient’s brain to repair tissue damages caused by stroke. This will be achieved by first studying how the hESCs behave in the culture dishes and by isolating the NSPCs from them. We will then make sure that the neurons produced are functional and non tumorigenic. Then, we will test the safety and efficacy of these functional neurons to restore the function of the stroke damaged neural tissue. If successful, the hESCs-derived NSPCs will represent a technically innovative and a viable option for clinical studies.
Statement of Benefit to California: 
Stroke has the highest annual incidence of any neurological disorder, it affects more people than Alzheimer’s disease, traumatic brain injury, epilepsy and Parkinson’s disease. In the United States, more than 750,000 individuals suffer from stroke every year. There are also approximately 5.4 million stroke survivors and about one-third of them are unable to care for themselves and almost 75% are impaired in some activities of their daily life. The estimated economic burden from stroke exceeds $56.8 billion per year in the United States. Due to the lack of effective therapies, these numbers will increase in the future. A recent study reports that the total cost of stroke from 2005-2050 in the US is projected to top $2 trillion dollars. Currently the only approved stroke treatment is a type of drug called a thrombolytic that breaks up the blood clot that caused the stroke. This drug is only effective within three hours after the clot forms and before severe brain damage can occur. However, if the stroke victim has a pre-existing medical condition, then thrombolytic treatment is too risky because it may cause excessive bleeding. Thus, only 1-4% of stroke patients are eligible and benefit from this treatment. Regenerative medicine is developing as a promising approach to repair diseased or injured brain cells through stem cell-based therapy. The rationale is to replace lost brain cells and allow or improve the re-establishment of tissue function. Recent study results in animal models of stroke are encouraging us to move this research forward. In humans, the safety of the concept of cell transplantation has been demonstrated. However, further studies are hampered by the need to find an ideal cell line that is not only safe and improves the patient’s medical condition but one that also can be economically produced in large scale for clinical use. Our research is developing neural cell lines from human embryonic stem cells (hESCs) for their transplantation into a patient’s brain to repair tissue damaged by stroke. If successful, these cells will be valuable as a viable option for clinical studies. Californians who suffer from a stroke and those who care for them would benefit from this therapy that can potentially enhance the patient’s motor function and make them less dependent. This will improve the California health care system and reduce the long-term health care cost burden. In addition, the development of stem cell-based therapies and the intellectual property behind them will benefit California’s economy by creating jobs and treatments that will generate substantial tax revenue.
Review Summary: 
SYNOPSIS: Embryonic stem cells possess a nearly unlimited self-renewal capacity and developmental potential to differentiate into virtually any cell type of the organism. As such, human embryonic stem cells (hESCs) are currently the preferred cell source for regenerative medicine. Recently, the Principal Investigator (PI) claims to have demonstrated that primary neural progenitors induced motor behavioral improvement after transplantation into the rat stroke model. However, unlike the hESCs, the primary neural progenitors are neither amenable for large-scale production nor for the appropriate quality assurance program needed to meet a sufficient patient population for multi-center clinical trials. Therefore, it is proposed to use the same experimental paradigm to test the safety and efficacy of the hESC-derived neural stem/progenitor cells (NSPCs) in the rat stroke model. Aim 1. To optimize and characterize one of the NSPC-derived cell lines (SUD56) for transplantation. Aim 2. To assess survival, neurite outgrowth and interaction with stroke-damaged explants. Aim 3. To transplant optimized populations of SUD56 into the animal model. INNOVATION AND SIGNIFICANCE: There is no question that stroke offers a very reasonable target for a potent stem cell-derived neural precursor cell for replacement approaches because of the often focal nature of the injury. hESCs are without question a potent stem cell source for generating large numbers of neural precursor cells that could be used for this therapeutic approach once the proper ex vivo growth conditions and in vivo models and transplant approaches are developed and refined. The claim that this approach is limited by presently limited supplies of neural precursor cells is true, and the nearly unlimited self-renewal capacity of EhSCs and their ability to generate multilineage neural cell diversity makes them a prime target for the types of studies proposed here. STRENGTHS: The recent preliminary studies from the PI’s lab, looking at hESC-derived NSPCs in a defined media for long-term passaging (using a new single-cell dissociation protocol) and expansion, seem promising. The observation that they express uniquely neural markers, and that the lines did not express any of the hESC pluripotent markers (e.g. SSEA3 aand Oct4) is very encouraging. It is a strength that this proposal will focus on an already established line (SUD56) using protocols already in place in the PI’s lab for in vitro optimization and characterization, as well for in vitro (explant) and in vivo transplantation studies. The PI is a stroke expert who will challenge hESC-derived neural precursor cell lines to operate in a hostile adult CNS setting. He/she has the appropriate experience and is asking the right questions to meet this challenge. Neurite-growth assays are important for establishing the ability of hES –derived NSPCs to properly integrate in the ischemic cortex. The recruitment of Dr. Malenka to help with the functional characterization of the NSPCs into different CNS neuron types is a big plus. WEAKNESSES: The reviewer is not convinced that the explant-SUD56 cell line co-culture experiments are properly designed to allow for the best characterization of the functional maturation of these new neurons. Long-term explant-grafted precursor cell protocols have been developed by others (e.g. see Benninger et al., 2003) that could facilitate such studies. If the explant is deteriorating as expected during the NSCP cell maturation following co-planting, the information gleaned from these tedious and time-consuming studies may not be that useful. The behavioral studies in Aim 3 seems a bit over-ambitious for a 2 year study as proposed here, since the cell characterization of the new cell lines in Aim 1, including rigorous neurite growth assays needed, and the potentially problematic organotypic studies of Aim 2, are together a substantial body of work to complete. DISCUSSION: There was no discussion following the reviewers' comments
Conflicts: 

© 2013 California Institute for Regenerative Medicine