Blood Disorders

Coding Dimension ID: 
278
Coding Dimension path name: 
Blood Disorders

Niche-Focused Research: Discovery & Development of Hematopoietic Regenerative Factors

Funding Type: 
Research Leadership 14
Grant Number: 
LA1_C14-08014
ICOC Funds Committed: 
$5 174 715
Disease Focus: 
Blood Disorders
Stem Cell Use: 
Adult Stem Cell
Public Abstract: 
Bone marrow and peripheral blood transplantation utilizing blood stem cells can provide curative treatment for patients with cancers and non-cancerous diseases of the blood and immune systems. Such treatments can be curative because the stem cells contained within the bone marrow or peripheral blood of healthy donors are capable of replacing the entirety of the patient’s blood system and providing a new immune system which can eradicate the patient’s cancer cells. The application of blood stem cell transplantation could be applied to a much larger population of patients if methods could be developed to expand blood stem cells in vitro or in vivo. This would be particularly beneficial for the broadened application of human cord blood transplantation for the many patients who lack an immune-matched sibling or unrelated donor. Furthermore, a method to expand human blood stem cells in vivo could be highly beneficial for the thousands of patients with cancer who require toxic chemotherapy which frequently results in decreased blood counts, infections and bleeding complications. A systemic treatment (i.e. a shot) which could cause blood stem cells to grow and produce more blood cells in patients could markedly improve patient’s outcomes after they receive such chemotherapy in the curative treatment of cancer. However, the development of treatments capable of inducing human blood stem cells to grow in the body has been very slow, in part due to a lack of understanding of the processes which govern blood stem cell growth in general. In my laboratory, we have developed mouse genetic models which allow us to discover new proteins produced in the bone marrow (the “soil” where blood stem cells reside) which make blood stem cells grow. We have recently discovered that 2 proteins are secreted by blood vessels within the bone marrow and cause blood stem cells to grow rapidly following damage with radiation. We are currently in the process of developing one of these into a growth factor that we can deliver to patients via injection as a means to cause their blood stem cells to grow after cord blood transplantation or following chemotherapy treatment for cancer. In this proposal, we will utilize our unique mouse models to discover the additional growth factors that make blood stem cells grow and we will perform pre-clinical studies to test whether these newly discovered growth factors can cause human blood stem cells to grow in vitro and in vivo. This proposal has the potential to generate new understanding of how human stem cells grow in vivo and to facilitate the development of new therapies which can regenerate human blood stem cells and the blood system as a whole in patients.
Statement of Benefit to California: 
My research program has both basic science and pre-clinical components which I believe will benefit California in several important ways: First, my basic research program will contribute new fundamental knowledge in stem cell biology which will benefit students, fellows and faculty. My research will also synergize with other campus laboratories and other centers in California and will lead to collaborations and accelerated translation of these discoveries for regenerative medicine. Second, my research program has the potential to directly benefit patients in California. We have already discovered two niche-derived proteins which promote hematopoietic stem cell regeneration in vivo and are focusing substantial efforts now to develop these proteins as therapeutics for Phase I clinical trials. For example, we are developing one of the HSC regenerative factors which we discovered for a Phase I clinical trial to test its efficacy as a systemic therapy to accelerate cord blood engraftment and hematologic recovery in adult cord blood transplant patients. This has literal potential benefit for patients since approximately 10% of cord blood transplant patients die from complications of graft failure or delayed hematologic recovery. In addition, patients with cancer who receive myelosuppressive chemotherapy can potentially benefit from systemic administration of [REDACTED] or other HSC regenerative factors that we discover to accelerate hematologic recovery after chemotherapy. If we are able to show that administration of such regenerative factors can accelerate hematologic recovery in patients after chemotherapy, then remission rates for cancer patients may increase via more effective delivery of curative chemotherapy on time and to completion. Third, my research will provide new intellectual property. These inventions from my laboratory will be available for licensure to biotech or pharmaceutical companies in California. I have experience with licensing inventions from my laboratory to biotech companies and am eager to see my future inventions licensed to accelerate development for regenerative medicine. Fourth, my research program will provide new jobs and professional opportunities. At present, my research program provides partial or complete funding for more than 30 employees internally and more than 30 employees at our partner institutions in academia and biotechnology. I will also bring substantial federal research funding with me to California and will be hiring new fellows, technicians and faculty promptly upon my arrival. Taken together, I am hopeful that my research program will have a major benefit for the scientific community of California, for patients who may benefit from treatments we are developing, for the biotechnology community via the development of new intellectual property and for the larger economy via the creation of many new jobs. I sincerely look forward to the opportunity to bring my program to California.

Generation of functional cells and organs from iPSCs

Funding Type: 
Research Leadership 12
Grant Number: 
LA1_C12-06917
ICOC Funds Committed: 
$6 152 065
Disease Focus: 
Blood Disorders
Stem Cell Use: 
iPS Cell
oldStatus: 
Closed
Public Abstract: 
The development of induced pluripotent stem cell (iPSC) technology may be the most important advance in stem cell biology for the future of medicine. This technology allows one to generate a patient’s own pluripotent stem cells (PSCs) from skin or blood cells. iPSCs can then be reprogrammed to multiply and produce high quality mature cells for cell therapy. Because iPSCs are derived from a patient's own cells, therapies that use them will not stimulate unwanted immune reactions or necessitate lifelong immunosuppression. If organs can be generated from iPSCs, many patients with organ failure awaiting transplants will be helped. The goal of this project is to further develop iPSC technology to bring about personalized regenerative medicine for treating intractable diseases such as cancers, viral infections, genetic blood disorders, and organ failure. Specifically, we would like to establish three major core programs for generating from iPSCs: personalized immune cells; an unlimited supply of blood stem cells; and functional organs. First, we will generate iPSC-derived immune cells that kill viruses and cancer cells. Current immunotherapy uses immune cells that are exhausted (have limited ability to function and proliferate) after they multiply in a test tube. To supply active nonexhausted immune cells, iPSCs will be generated from a patient’s immune cells that target tumor cells and infections and then redifferentiated to mature immune cells with the same targets. Second, we aim to develop iPSC technology to generate blood stem cells that replenish all blood cells throughout life. Harvesting blood stem cells from a leukemia patient for transplantation back to the patient after chemotherapy and radiation has been challenging because few blood stem cells can be harvested and may be contaminated with cancer cells. Alternatively, transplanting blood stem cells from cord blood or another person requires genetic matching to prevent immune reactions. However, generating blood stem cells from a patient’s iPSCs may avoid contamination with cancer cells, immune reactions, and the need to find a matched donor. Furthermore, we aim to generate iPSCs from a patient with a genetic blood disease, correct the genetic defect in the iPSCs, and generate from these corrected iPSCs healthy blood stem cells that may be curative when transplanted back into the patient. Lastly, we will try to generate from iPSCs not just mature cells, but organs for transplantation, to potentially address the tremendous shortage of donated organs. In a preliminary study, we generated preclinical models that could not develop pancreases. When we injected stem cells into these models, they developed functional pancreases derived from the injected cells and survived to adulthood. We hope that within 10 years, we will be able to provide a needed organ to a patient by growing it from the patient’s own PSCs in a compatible animal.
Statement of Benefit to California: 
Cancer is the second leading cause of death, accounting for 24% of all deaths in the U.S. Nearly 55,000 people will die of the disease--about 150 people each day or one of every four deaths in California. In 2012, nearly 144,800 Californians will be diagnosed with cancer. We need effective treatment to cure cancer. End-stage organ failure is another difficult disease to treat. Transplantation of kidneys, liver, heart, lungs, pancreas, and small intestine has become an accepted treatment for organ failure. In California, more than 21,000 people are on the waiting lists at transplant centers. However, one in three of these people will die waiting for transplants because of the shortage of donated organs. While end-stage renal failure patients can survive for decades with hemodialysis treatment, they suffer from high morbidity and mortality. In addition, the high medical costs for increasing numbers of dialysis patients is a social issue. We need to find a way to increase organs that can be used for transplantation. In our proposed projects, we aim to use iPSC technology and recent discoveries to develop new methods for treating cancers, viral infections, and organ failure. More specifically, we will pursue our recent discoveries using iPSCs to: (1) multiply person’s T cells that specifically target cancers and viral infections; (2) generate normal blood-forming stem cells that can be transplanted back into a patient to correct a blood disease (3) regenerate tissues and organs from a patient’s cells for transplantation back into that patient. These projects are likely to benefit the state of California in several ways. Many of the methods, cells, and reagents generated by this research will be patentable, forming an intellectual property portfolio shared by the state and the institutions where the research is performed. The funds generated from the licensing of these technologies will provide revenue for the state, will help increase hiring of faculty and staff (many of whom will bring in other, out-of-state funds to support their research), and could be used to ameliorate the costs of clinical trials--the final step in translation of basic science research to clinical use. Most importantly, this research will set the platform for stem cell-based therapies. Because tissue stem cells are capable of lifelong self-renewal, these therapies have the potential to provide a single, curative treatment. Such therapies will address chronic diseases that have no cure and cause considerable disability, leading to substantial medical expenses and loss of work. We expect that California hospitals and health care entities will be first in line for trials and therapies. Thus, California will benefit economically and the project will help advance novel medical care.

A Treatment For Beta-thalassemia via High-Efficiency Targeted Genome Editing of Hematopoietic Stem Cells

Funding Type: 
Strategic Partnership II
Grant Number: 
SP2-06902
ICOC Funds Committed: 
$6 374 150
Disease Focus: 
Blood Disorders
Pediatrics
Stem Cell Use: 
Adult Stem Cell
oldStatus: 
Active
Public Abstract: 
β-thalassemia is a genetic disease caused by diverse mutations of the β-globin gene that lead to profoundly reduced red blood cell (RBC) development. The unmet medical need in transfusion-dependent β-thalassemia is significant, with life expectancy of only ~30-50 years despite standard of care treatment of chronic blood transfusions and iron chelation therapy. Cardiomyopathy due to iron overload is the major cause of mortality, but iron-overload induced multiorgan dysfunction, blood-borne infections, and other disease complications impose a significant physical, psychosocial and economic impact on patients and families. An allogeneic bone marrow transplant (BMT) is curative. However, this therapy is limited due to the scarcity of HLA-matched related donors (<20%) combined with the significant risk of graft-versus-host disease (GvHD) after successful transplantation of allogeneic cells. During infancy, gamma-globin-containing fetal hemoglobin protects β-thalassemia patients from developing disease symptoms until gamma globin is replaced by adult-type β-globin chains. The proposed therapeutic intervention combines the benefits of re-activating the gamma globin gene with the curative potential of BMT, but without the toxicities associated with acute and chronic immunosuppression and GvHD. We hypothesize that harvesting hematopoietic stem and progenitor cells (HSPCs) from a patient with β-thalassemia, using genome editing to permanently re-activate the gamma globin gene, and returning these edited HSPCs to the patient could provide transfusion independence or greatly reduce the need for chronic blood transfusions, thus decreasing the morbidity and mortality associated with iron overload. The use of a patient’s own cells avoids the need for acute and chronic immunosuppression, as there would be no risk of GvHD. Moreover, due to the self-renewing capacity of HSPCs, we anticipate a lifelong correction of this severe monogenic disease.
Statement of Benefit to California: 
Our proposed treatment for transfusion dependent β-thalassemia will benefit patients in the state by offering them a significant improvement over current standard of care. β-thalassemia is a genetic disease caused by diverse mutations of the β-globin gene that lead to profoundly reduced red blood cell (RBC) development and survival resulting in the need for chronic lifelong blood transfusions, iron chelation therapy, and important pathological sequelae (e.g., endocrinopathies, cardiomyopathies, multiorgan dysfunction, bloodborne infections, and psychosocial/economic impact). Incidence is estimated at 1 in 100,000 in the US, but is more common in the state of California (incidence estimated at 1 in 55,000 births) due to immigration patterns within the State. While there are estimated to be about 1,000-2,000 β-thalassemia patients in the US, one of our proposed clinical trial sites has the largest thalassemia program in the Western United States, with a population approaching 300 patients. Thus, the state of California stands to benefit disproportionately compared to other states from our proposed treatment for transfusion dependent β-thalassemia. An allogeneic bone marrow transplant (BMT) is curative for β-thalassemia, but limited by the scarcity of HLA-matched related donors (<20%) combined with the significant risk of graft-versus-host disease (GvHD) after successful transplantation of allogeneic cells. Our approach is to genetically engineer the patient’s own stem cells and thus (i) solve the logistical challenge of finding an appropriate donor, as the patient now becomes his/her own donor; and (ii) make use of autologous cells abrogating the risk of GvHD and need for acute and chronic immunosuppression. Our approach offers a compelling pharmacoeconomic benefit to the State of California and its citizens. A lifetime of chronic blood transfusions and iron chelation therapy leads to a significant cost burden; despite this, the prognosis for a transfusion dependent β-thalassemia patient is still dire, with life expectancy of only ~30-50 years. Our proposed one-time treatment aims to reduce or eliminate the need for costly chronic blood transfusions and iron chelation therapy, while potentially improving the clinical benefit to patients, including the morbidity and mortality associated with transfusion-induced iron overload.

Development of a cell and gene based therapy for hemophilia

Funding Type: 
Early Translational IV
Grant Number: 
TR4-06809
ICOC Funds Committed: 
$2 322 440
Disease Focus: 
Blood Disorders
Liver Disease
Pediatrics
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Closed
Public Abstract: 
Hemophilia B is a bleeding disorder caused by the lack of FIX in the plasma and affects 1/30,000 males. Patients suffer from recurrent bleeds in soft tissues leading to physical disability in addition to life threatening bleeds. Current treatment (based on FIX infusion) is transient and plagued by increased risk for blood-borne infections (HCV, HIV), high costs and limited availability. This has fueled a search for gene/cell therapy based alternatives. Being the natural site of FIX synthesis, the liver is expected to provide immune-tolerance and easy circulatory access. Liver transplantation is a successful, long-term therapeutic option but is limited by scarcity of donor livers and chronic immunosuppression; making iPSC-based cell therapy an attractive prospect. As part of this project, we plan to generate iPSCs from hemophilic patients that will then be genetically corrected by inserting DNA capable of making FIX. After validation for correction, we will then differentiate these iPSCs into liver cells that can be transplanted into our mouse model of hemophilia that is capable of accepting human hepatocytes and allowing their proliferation. These mice exhibit disease symptoms similar to human patients and we propose that by injecting our corrected liver cells they will exhibit normal clotting as measured by various biochemical and physiological assays. If successful, this will provide a long-term cure for hemophilia and other liver diseases.
Statement of Benefit to California: 
Generation of iPSCs from adult cells unlocked the potential of tissue engineering, replacement and cell transplant therapies to cure a host of debilitating diseases without the ethical concerns of working with embryos or the practical problems of immune-rejection. We aim to develop a POC for a novel cell- and gene-therapy based approach towards the treatment of hemophilia B. In addition to the obvious and direct benefit to the affected patients and families by providing a potential long-term cure; the successful development of our proposal will serve as a POC for moving other iPSC-based therapies to the clinic. Our proposal also has the potential to treat a host of other hepatic diseases like alpha-1-antitrypsin deficiency, Wilson’s disease, hereditary hypercholesterolemia, etc. These diseases have devastating effects on the patients in addition to the huge financial drain on the State in terms of the healthcare costs. There is a pressing need to find effective solutions to such chronic health problems in the current socio-economic climate. The work proposed here seeks to redress this by developing cures for diseases that, if left untreated, require substantial, prolonged medical expenditures and cause increased suffering to patients. Being global leaders in these technologies, we are ideally suited to this task, which will establish the state of California at the forefront of medical breakthroughs and strengthen its biomedical/biotechnology industries.

Beta-Globin Gene Correction of Sickle Cell Disease in Hematopoietic Stem Cells

Funding Type: 
Early Translational IV
Grant Number: 
TR4-06823
ICOC Funds Committed: 
$1 815 308
Disease Focus: 
Blood Disorders
Pediatrics
Stem Cell Use: 
Adult Stem Cell
Cell Line Generation: 
Adult Stem Cell
oldStatus: 
Active
Public Abstract: 
Disorders affecting the blood, including Sickle Cell Disease (SCD), are the most common genetic disorders in the world. SCD causes significant suffering and early death, despite major improvements in medical management and advances in understanding the complex disease-related biology. A bone marrow transplant (BMT) can greatly benefit patients with SCD, by providing a life-long source of normal red blood cells. However, BMT is limited by the availability of suitable donors and immune complications, especially for the more than 80% of patients who lack a matched sibling donor. An alternative treatment approach for SCD is to isolate some of the patient’s own bone marrow and then use gene therapy methods to correct the sickle gene defect in the blood stem cells before transplanting them back into the patient. The gene-corrected stem cells could make normal blood cells for the life of the patient, essentially eliminating the SCD. Such an approach would avoid the complications typically associated with transplants from non-matched donors. We will define the optimal techniques to correct the sickle gene mutation in the bone marrow stem cells to develop as a therapy for patients with SCD.
Statement of Benefit to California: 
Development of methods for regenerative medicine using stem cells will have widespread applications to improve the health and to provide novel, effective therapies for millions of Californians and tens of millions of people worldwide. Many severe medical conditions can be cured or improved by transplantation of blood-forming hematopoietic stem cells (HSC), including genetic diseases of blood cells, such as sickle cell disease and inborn errors of metabolism, cancer and leukemia, and HIV/AIDS. Precise genetic engineering of stem cells to repair inherited mutation may be the best way to correct genetic defects affecting the mature cells they produce. This project will advance methods to precisely repair the genetic defect that underlies sickle cell disease in hematopoietic stem cells, which can then be transplanted to ameliorate the disease. These advances will have direct and immediate applications to enhance current medical therapies of sickle cell disease and will more broadly help to advance the capacities for regenerative medicine. All scientific findings and biomedical materials produced from our studies will be publicly available to non-profit and academic organizations in California, and any intellectual property developed by this Project will be developed under the guidelines of CIRM to benefit the people of the State of California.

A Phase 1/2, Open Label Study Evaluating the Safety and Efficacy of Gene Therapy in Subjects with β-Thalassemia by Transplantation of Autologous Hematopoietic Stem Cells [REDACTED]

Funding Type: 
Strategic Partnership I
Grant Number: 
SP1-06477
Investigator: 
ICOC Funds Committed: 
$9 363 335
Disease Focus: 
Blood Disorders
Stem Cell Use: 
Adult Stem Cell
Cell Line Generation: 
Adult Stem Cell
oldStatus: 
Closed
Public Abstract: 
[REDACTED] plans to carry out a Phase 1/2 study to evaluate the safety and efficacy of [REDACTED] for the treatment of β-Thalassemia Major(BTM). [REDACTED] consists of autologous patient hematopoietic stem cells(HSC) that have been genetically modified ex vivo with a lentiviral vector that encodes a therapeutic form of the β-globin gene. [REDACTED] is administered through autologous hematopoietic cell transplant(HCT), with the goal of restoring normal levels of hemoglobin and red blood cell(RBC) production in BTM patients who are dependent on RBC transfusions for survival. Because they cannot produce functional hemoglobin, BTM patients require lifelong RBC transfusions that cause widespread organ damage from iron overload. While hemosiderosis can be mitigated with chelation therapy, poor compliance, efficacy and tolerability remain key challenges, and a majority BTM patients die in their 3rd-5th decade. The only cure for BTM is allogeneic HCT, which carries a significant risk of mortality and morbidity from immune-incompatibility between the donor and recipient, and is hampered by the limited availability of HLA matched sibling donors. By stably inserting functional copies of β-globin into the genome of a patient’s own HSC, treatment with [REDACTED] promises to be a one-time transformative therapy for BTM. The β-globin gene in the [REDACTED] vector carries a single codon mutation [REDACTED] that allows for quantitative monitoring of therapeutic globin production but that does not alter oxygen carrying capacity. Treatment with an earlier version of the vector has been shown to correct β-thalassemia in mice [REDACTED]. In a clinical trial [REDACTED], 3 BTM patients were treated–one of whom became transfusion independent 1 year after treatment and remains so 4 years later. Given the prevalence of patients with a common BTM genotype in California, [REDACTED] plans to open at least 2, and up to 4, clinical sites in California. Development activities are on track to initiate the trial in 1H 2013, and to complete the trial with 2 years of follow-up within the award window. [REDACTED] has completed a pre-IND meeting with the FDA and successfully manufactured a GMP lot of [REDACTED] vector that is available for clinical use. The Company expects to complete all IND enabling activities by Q4 2012. In the last year, the company has made scientific advances that have allowed for a significant improvement in the efficiency of HSC genetic modification that will be help ensure clinical efficacy in BTM. Moreover, through collaborations with contract manufacturers, [REDACTED] is now producing large scale GMP lots of vector, and is on track to qualify a GMP cell processing facility with commercial capabilities prior to study initiation. [REDACTED].
Statement of Benefit to California: 
The company expects to spend a major component of its financial resources conducting business within the state of California during the period of this CIRM award. Specifically: 1) we will have at least two clinical sites in California, and more likely up to 4 sites, 2) our viral vector manufacturing will occur in California, 3) our cell processing will occur in California, 4) we will hire several consultants and full-time employees within California to support the program. Overall, several million dollars will be spent employing the services of people, academic institutions, and other companies within the state of California. Moreover, the disease we aim to treat occurs at a substantially greater rate of in California than other parts of the United States. As such, it is a significant public health concern, for which our therapy could provide a dramatically improved outcome and significant reduction in the lifetime cost of treatment, along with increased productivity. Due to the prevalence of the disease in California, if brought to the market, the pharmacoeconomic and social benefit of our therapy will accrue disproportionately to the state of California.

Curing Hematological Diseases

Funding Type: 
Early Translational I
Grant Number: 
TR1-01273
ICOC Funds Committed: 
$6 649 347
Disease Focus: 
Blood Disorders
Immune Disease
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Closed
Public Abstract: 
The primary aim of this project is to develop treatments for incurable diseases of the blood and immune system. X-linked Severe Combined Immunodeficiency (X-SCID) and Fanconi anemia (FA) are two blood diseases where mutations in a single gene results in the disease. XSCID, more commonly known as the “bubble boy” disease, is characterized by a complete failure of the immune system, and typically results in early childhood fatality. The most common treatment for X-SCID is bone marrow transplant using a matched sibling donor. Unfortunately, the lack of suitable donors limits the application of this treatment. In 2000, the first gene therapy "success" resulted in X-SCID patients with a functional immune system. These trials were stopped when it was discovered that several patients in one trial had developed lymphoma, a blood related cancer resulting from unintended consequences of the therapy. FA is a disease where the stability of the genome is compromised and results in premature cell death and lethal anemia. Gene therapy trials for such patients have been largely unsuccessful due to the inability to culture the cells long enough for the correction of the gene. Like XSCID there is a shortage of suitable bone marrow donors for patients, thus development of treatments via other methods is warranted. From this study and others we have learned 1) gene therapy can work to cure certain diseases, 2) adequate safeguards must be developed to prevent unintended cancer formation, and 3) we need better sources of matched cells and tissues to avoid the problems of rejection. Our proposal will be using one of the most exciting new developments in regenerative medicine, that is the ability to reprogram a patient’s skin, or even hair follicle back to an induced pluripotent stem (iPS) cell, which is similar to embryonic stem cells, without involving embryo destruction. The iPS cell is a good candidate for repair of the specific genetic defects that cause diseases like X-SCID and FA. The reprogrammed, genetically corrected cells are a perfect match for transplantation therapy since they come from the patient. At this stage the corrected cells will be augmented with additional safety factors that work to avoid the downstream potential for cancer. These safe and genetically corrected cells will then be coaxed back into the cells that form the blood and immune systems and used for transplant therapy. In this work we will be using mouse models that mimic the human diseases of X-SCID and FA and are amenable to treatment with human hematopoietic stem cells. We will be working with human patient and disease-specific cells to demonstrate the feasibility and evaluate the safety in a pre-clinical setting to advance these pioneering new techniques that combine the latest developments in regenerative medicine and gene therapy. Our proposed work will also benefit the successful stem cell based therapies for many other diseases like Parkinson’s and diabetes.
Statement of Benefit to California: 
The idea that embryonic stem cells (ES cells) have the ability to differentiate into a variety of cell types, tissues, and organs, opens the possibility of tissue engineering, replacement, and cell transplant therapies to cure diseases ranging from Parkinson’s, Alzheimer’s, diabetes, blood disorders and a host of other debilitating disorders. Rarely comes along a new technology that has the potential to make such a major impact on human health. Recently researchers have discovered methods to reprogram adult fibroblasts and skin cells back into a cell referred to as induced pluripotent stem cell (iPS) that appears to be indistinguishable from the pluripotent ES cell. This is accomplished without the need for embryo destruction and offers great potential to alleviate the problems of immune rejection in cell or tissue transplantation by allowing a patient’s own cells to be reprogrammed, expanded then used in therapeutic applications. The principle aim of this proposal is to develop new technologies that can be used to treat two specific devastating hematological disorders X-linked Severe Combined Immunodeficiency (X-SCID) and Fanconi Anemia (FA). Both are rare genetic diseases, and both have devastating effects on the immune and blood systems. The successful development of therapies for these diseases will have an obvious and direct effect on the patients and their families affected by these diseases. From a broader perspective, the establishment of these regenerative medicine techniques has the potential to treat a vast array of disease like Parkinson’s, Alzheimer’s, diabetes and other blood disorders like thalassemia, Sickle cell anemia, and hemophilia. These diseases all have devastating effects on the patients afflicted, but they also place a tremendous burden on the State in terms of health care cost. Ever more, we need to spend state resources wisely and finding ways to reduce the continually increasing cost of long-term medical care is critical. The work proposed here seeks to do just that by creating outright cures for diseases that if left untreated require substantial and prolonged medical expenditures and incredible suffering for the patients and their families. In other regards keeping the state of California at the forefront of medical breakthroughs and strengthening our biomedical and biotechnology industries. We are a leading force in these fields, not only across the nation but also worldwide.
Progress Report: 
  • The primary aim of this project is to develop treatments for incurable diseases of the blood and immune system. X-linked Severe Combined Immunodeficiency (X-SCID) and Fanconi anemia (FA) are two blood diseases where mutations in a single gene results in the disease. XSCID, more commonly known as the “bubble boy” disease, is characterized by a complete failure of the immune system, and typically results in early childhood fatality. The most common treatment for X-SCID is bone marrow transplant using a matched sibling donor. Unfortunately, the lack of suitable donors limits the application of this treatment. In 2000, the first gene therapy "success" resulted in X-SCID patients with a functional immune system. These trials were stopped when it was discovered that several patients in one trial had developed lymphoma, a blood related cancer resulting from unintended consequences of the therapy. FA is a disease where the stability of the genome is compromised and results in premature cell death and lethal anemia. Gene therapy trials for such patients have been largely unsuccessful due to the inability to culture the cells long enough for the correction of the gene. Like XSCID there is a shortage of suitable bone marrow donors for patients, thus development of treatments via other methods is warranted.
  • From this study and others we have learned: 1) gene therapy can work to cure certain diseases, 2) adequate safeguards must be developed to prevent unintended cancer formation, and 3) we need better sources of matched cells and tissues to avoid the problems of rejection.
  • We proposed to reprogram a patient’s skin, or even hair follicle back to an induced pluripotent stem (iPS) cell, which is similar to embryonic stem cells, without involving embryo destruction. The iPS cell is a good candidate for repair of the specific genetic defects that cause diseases like X-SCID and FA. We have reprogrammed many patients cells to generate iPS. More importantly, we have gotten early hints of success in making hematopoietic stem cells and other blood cells from them. We have also started to make iPS cells from both X-SCID patients.
  • The primary aim of this project is to develop treatments for incurable diseases of the blood and immune system. X-linked Severe Combined Immunodeficiency (X-SCID) and Fanconi anemia (FA) are two blood diseases where mutations in a single gene results in the disease. XSCID, more commonly known as the “bubble boy” disease, is characterized by a complete failure of the immune system, and typically results in early childhood fatality. The most common treatment for X-SCID is bone marrow transplant using a matched sibling donor. Unfortunately, the lack of suitable donors limits the application of this treatment. In 2000, the first gene therapy "success" resulted in X-SCID patients with a functional immune system. These trials were stopped when it was discovered that several patients in one trial had developed lymphoma, a blood related cancer resulting from unintended consequences of the therapy. FA is a disease where the stability of a patients genome is compromised and results in premature cell death and lethal anemia. Gene therapy trials for such patients have been largely unsuccessful due to the inability to culture the affected cells long enough for the correction of the gene. Like XSCID there is a shortage of suitable bone marrow donors for patients, thus development of treatments via other methods is warranted.
  • From this study and others we have learned: 1) gene therapy can work to cure certain diseases, 2) adequate safeguards must be developed to prevent unintended cancer formation, and 3) we need better sources of matched cells and tissues to avoid the problems of rejection.
  • Our approach starts with a patient’s skin, hair follicle or other easily accessible adult cell/tissue sample and employs a newly developed and robust technique to safely reprogram these cells back to an induced pluripotent stem (iPS) cell fate, which is similar to that of embryonic stem cells in potential, but is patient specific thereby avoiding downstream problems of immune rejection. The iPS cell is a good candidate for repair of the specific genetic defects that cause diseases like X-SCID and FA. We have successfully reprogrammed cells from human patients of each of these diseases to generate iPS cell lines. We are employing the latest technology to perform genetic correction of these cells. In parallel we are advancing the state-of-the-art in developing reliable methods to direct the differentiation of these disease corrected stem cells into the appropriate therapeutic cell types capable of reconstituting the blood and immune systems and thereby effecting cures for these hematological diseases.
  • The primary aim of this project is to develop treatments for incurable diseases of the blood and immune system. X-linked Severe Combined Immunodeficiency (X-SCID) and Fanconi anemia (FA) are two blood diseases where mutations in a single gene results in the disease. XSCID, more commonly known as the “bubble boy” disease, is characterized by a complete failure of the immune system, and typically results in early childhood fatality. The most common treatment for X-SCID is bone marrow transplant using a matched sibling donor. Unfortunately, the lack of suitable donors limits the application of this treatment. In 2000, the first gene therapy "success" resulted in X-SCID patients with a functional immune system. These trials were stopped when it was discovered that several patients in one trial had developed lymphoma, a blood related cancer resulting from unintended consequences of the therapy. FA is a disease where the stability of a patients genome is compromised and results in premature cell death and lethal anemia. Gene therapy trials for such patients have been largely unsuccessful due to the inability to culture the affected cells long enough for the correction of the gene. Like XSCID, there is a shortage of suitable bone marrow donors for patients, thus development of treatments via other methods is warranted.
  • From this study and others we have learned: 1) gene therapy can work to cure certain diseases, 2) adequate safeguards must be developed to prevent unintended cancer formation, and 3) we need better sources of matched cells and tissues to avoid the problems of rejection.
  • Our approach starts with a patient’s skin, hair follicle or other easily accessible adult cell/tissue sample and employs a newly developed and robust technique to safely reprogram these cells back to an induced pluripotent stem (iPS) cell fate, which is similar to that of embryonic stem cells in potential, but is patient specific thereby avoiding downstream problems of immune rejection. The iPS cell is a good candidate for repair of the specific genetic defects that cause diseases like X-SCID and FA. We have successfully reprogrammed cells from human patients of each of these diseases to generate iPS cell lines. We are employing the latest technology to perform genetic correction of these cells. In parallel we are advancing the state-of-the-art in developing reliable methods to direct the differentiation of these disease corrected stem cells into the appropriate therapeutic cell types capable of reconstituting the blood and immune systems and thereby effecting cures for these hematological diseases.
  • This project is focused on developing treatments for incurable diseases of the blood and immune system. X-linked Severe Combined Immunodeficiency (X-SCID) and Fanconi anemia (FA) are two blood diseases where mutations in a single gene results in the disease. XSCID, more commonly known as the “bubble boy” disease, is characterized by a complete failure of the immune system, and typically results in early childhood fatality. The most common treatment for X-SCID is bone marrow transplant using a matched sibling donor. Unfortunately, the lack of suitable donors limits the application of this treatment. In 2000, the first gene therapy "success" resulted in X-SCID patients with a functional immune system. These trials were stopped when it was discovered that several patients in one trial had developed lymphoma, a blood related cancer resulting from unintended consequences of the therapy. FA is a disease where the stability of a patients genome is compromised and results in premature cell death and lethal anemia. Gene therapy trials for such patients have been largely unsuccessful due to the inability to culture the affected cells long enough for the correction of the gene. Like XSCID, there is a shortage of suitable bone marrow donors for patients, thus development of treatments via other methods is warranted. From this study and others we have learned: 1) gene therapy can work to cure certain diseases, 2) adequate safeguards must be developed to prevent unintended cancer formation, and 3) we need better sources of matched cells and tissues to avoid the problems of rejection.
  • Our approach starts with a patient’s skin, hair follicle or other easily accessible adult cell/tissue sample and employs newly developed and robust techniques to safely reprogram these cells back to an induced pluripotent stem (iPS) cell fate, which is similar to that of embryonic stem cells in potential, but is patient specific thereby avoiding downstream problems of immune rejection. The iPS cell is a good candidate for repair of the specific genetic defects that cause diseases like X-SCID and FA. To date, we have successfully reprogrammed cells from human patients of each of these diseases to generate iPS cell lines. We have also had success employing the latest technology to perform genetic correction of these cells, effectively repairing the DNA mutations that cause the diseases. In parallel we are advancing the state-of-the-art in developing reliable methods to direct the differentiation of these disease corrected stem cells into the appropriate therapeutic cell types capable of reconstituting the blood and immune systems and thereby effecting cures for these hematological diseases.

Prospective isolation of hESC-derived hematopoietic and cardiomyocyte stem cells

Funding Type: 
Comprehensive Grant
Grant Number: 
RC1-00354
ICOC Funds Committed: 
$2 636 900
Disease Focus: 
Blood Disorders
Heart Disease
Immune Disease
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 
The capacity of human embryonic stem cells (hESCs) to perpetuate themselves indefinitely in culture and to differentiate to all cell types of the body has lead to numerous studies that aim to isolate therapeutically relevant cells for the benefit of patients, and also to study how genetic diseases develop. However, hESCs can cause tumors called teratomas when placed in the body and therefore, we need to separate potentially beneficial cells from hazardous hESCs. Thus, potential therapeutics cannot advance until the development of methodologies that eliminate undifferentiated cells and enrich tissue stem cells. In our proposal we hope to define the cell surface markers that are differentially expressed by committed hESC-derived stem cells and others that are expressed by teratogenic hESCs. To do this we will carry out a large screen of cell subsets that form during differentiation using a collection of unique reagents called monoclonal antibodies, many already obtained or made by us, to define the cell-surface markers that are expressed by teratogenic cells and others that detect valuable tissue stem cells. This collection, after filing for IP protection, would be available for CIRM investigators in California. We were the first to isolate mouse and human adult blood-forming stem cells, human brain stem cells, and mouse muscle stem cells, all by antibody mediated cell-sorting approaches. Antibody mediated identification of cell subsets that arise during early hESC differentiation will allow separation and characterization of defined subpopulations; we would isolate cells that are committed to the earliest lineage known to form multiple cell types in the body including bone, blood, heart and muscle. These cells would be induced to differentiate further to the blood forming and heart muscle forming lineages. Enriched, and eventually purified hESC-derived blood-forming stem cells and heart muscle stem cells will be tested for their potential capacity to engraft and improve function in animal models. Blood stem cells will be transplanted into immunodeficient mice to test their capacity to give rise to all blood cell types; and heart muscle stem cells will be transferred to mouse hearts that had an artificial coronary artery blockage, a model for heart attack damage. Finally, we will test the capacity of blood stem cell transplantation to induce transplantation tolerance towards heart muscle stem cells from the same donor cell line. Transplantation tolerance in this case means that the heart cells would be accepted as ‘self’ by the mouse that had it’s unrelated donor immune system replaced wholly or in part by blood forming stem cells from the same hESC line that gave rise to the transplantable heart stem cells, and therefore would not be rejected by it’s own immune system. This procedure would allow transplantation of beneficial tissues such as heart, insulin-producing cells, etc., without the use of immunosuppressive drugs.
Statement of Benefit to California: 
The principle objective of this proposal is to develop reagents which, in combinations, can identify and isolate tissue-regenerating stem cells derived from hESC lines. The undifferentiated hESCs are dangerous for transplantation into humans, as they cause tumors. We propose to prepare reagents that identify and can be used to delete or prospectively isolate these tumor-causing undifferentiated hESCs. HESC-derived tissue stem cells have the potential to regenerate damaged tissues and organs, and don’t cause tumors. We propose to develop reagents that can be used to identify and prospectively isolate pure human blood-forming stem cells derived from hESCs, and separately other reagents that can be used to identify and prospectively isolate pure heart-forming stem or progenitor cells. These “decontaminated” hESC-derived tissue stem cells may eventually be used to treat human tissue degenerative diseases. These reagents could also be used to isolate the same cells from somatic cell nuclear transfer (SCNT)-derived pluripotent stem cell lines from patients with genetic diseases. This procedure would enable us to analyze the effects of the genetic abnormalities on blood stem and progenitor cells in patients with genetic blood and immune system disorders, and on heart stem and progenitor cells in patients with heart disorders. The antibodies and stem cells (hESCs, tissue regenerating, etc) that will be isolated from patients with specific diseases will be invaluable tools that can be used to create model(s) for understanding the diseases and their progression. In addition, the antibodies and the stem cells generated in these studies are entities that could be patented or protected by copyright, forming an intellectual property portfolio shared by the state and the state institutions wherein the research was carried out. The funds generated from the licensing of these technologies will help pay back the state, will help support increasing faculty and staff (many of whom bring in other, out of state funds for their research), and could be used to ameliorate the costs of clinical trials. Only California businesses are likely to be able to license these antibodies and cells, to develop them into diagnostic and therapeutic entities; such businesses are the heart of the CIRM strategy to enhance the California economy. Most importantly, however, is that this research will lead to tissue stem cell therapies. Such therapies will address chronic diseases that cause considerable disability and misery, currently have no cure, and therefore lead to huge medical expenses. Because tissue stem cells renew themselves for life, stem cell therapies are one-time therapies with curative intent. We expect that California hospitals and health care entities will be first in line for trials and therapies, and for CIRM to negotiate discounts on such therapies for California taxpayers, thus California will benefit both economically and with advanced novel medical care.
Progress Report: 
  • The objectives of our proposal are the isolations of blood-forming and heart-forming stem cells from human embryonic stem cell (hESCs) cultures, and the generation of monoclonal antibodies (mAbs) that eliminate residual teratogenic cells from transplantable populations of differentiated hESCs. For isolation of progenitors, we hypothesized that precursors derived from hESCs could be identified and isolated using mAbs that label unique combinations of lineage-specific cell surface molecules. We used hundreds of defined mAbs, generated hundreds of novel anti-hESC mAbs, and used these to isolate and characterize dozens of hESC-derived populations. We discovered four precursor types from early stages of differentiating cells, each expressing genes indicative of commitment to either embryonic or extraembryonic tissues. Together, these progenitors are candidates to give rise to meso-endodermal lineages (heart, blood, pancreas, etc), and yolk sac, umbilical cord and placental tissues, respectively. Importantly, we have found that cells of the meso-endodermal population give rise to beating cardiomyocytes. We are currently enriching cardiomyocyte precursors from this population using cardiac-specific genetic markers, and are assaying the putative progenitors using electrophysiological assays and by transplantation into animal hearts (a test for restoration of heart function). In addition, we established in vitro conditions that effectively promote hESC-differentiation towards the hematopoietic (blood) lineages and isolated populations that resemble hematopoietic stem cells (HSCs) in both surface phenotype as well as lineage potentials, as determined by assays in vitro. We have generated hESC-lines that express the anti-apoptotic gene BCL2, and have found that these cells produce significantly greater amounts of hematopoietic and cardiac cells, because of their increased survival during culturing and sorting. We are currently isolating hematopoietic precursors from BCL2-hESCs and will test their ability to engraft in immunodeficient mice, to examine the capacity of hESC-derived HSCs to regenerate the blood system. Finally, we have utilized the novel mAbs that we prepared against undifferentiated hESCs, to deplete residual teratogenic cells from differentiated cultures that were transplanted into animal models. We discovered that following depletion teratoma rarely formed, and we expect to determine a final cocktail of mAbs for removal of teratogenic cells from transplantation products this year.
  • The main objective of our proposal is to isolate therapeutic stem cells and progenitors from human embryonic stem cells (hESCs) that give rise to blood and heart cells. Our approach involves isolation of differentiated precursor subset of cells using monoclonal antibodies (mAbs) and cell sorting instruments, and subsequent characterization of their respective hematopoietic and cardiomyogenic potential in culture as well as following engraftment into mouse models of disease. In addition, we aim to develop mAbs that specifically bind to undifferentiated hESCs for removal of residual teratoma-initiating cells from therapeutic cell preparations, to ensure transplantation safety.
  • We have made substantial advancement towards achieving these goals. First, we discovered that the initial differentiation of hESCs occurs through only 4-5 different progenitor types, of which one is destined to give rise to heart lineages. We purified this population using three novel cell surface markers, and found a significant enrichment of cardiomyocyte clones in colony formation assays that we developed. This subset also expressed particularly high levels of cardiac genes and was receptive to further differentiation into beating cardiomyocytes or vascular endothelial cells. When transplanted into immunodeficient mice these progenitors differentiated into ventricular myocytes and vascular endothelial cells. In the coming year we will perform transplantation experiments to evaluate whether they improve the functional outcome of heart infarction in hearts of mice. Second, we have optimized cell culture conditions and cell surface markers to sort hematopoietic progenitors derived from hESCs. We have also begun to transplant these populations into immunodeficient mouse recipients to identify blood-reconstituting hematopoietic populations. Third, we identified 5 commercial and 1 custom mAbs that are specific to human pluripotent cells (hESCs and induced pluripotent cells). We are currently testing the capacity of combinations of 3 pluripotency surface markers to remove all teratoma-initiating cells from transplanted differentiated cell populations. In summary, we expect provide functional validation of the blood and heart precursor populations that we identified from hESCs by the end term of this grant.
  • The main objective of our proposal is to isolate therapeutic stem and progenitor cells derived from human embryonic stem cells (hESCs) that can give rise to blood and heart cells. Our approach involves developing differentiation protocols to drive hematopoietic (blood) and cardiac (heart) development of hESCs, then to identify and isolate stem/progenitor cells using monoclonal antibodies (mAbs) specific to surface markers expressed on blood and heart stem/progenitor cells, and finally to characterize their functional properties in vitro and in vivo. In addition, we sought to develop mAbs that specifically bind to undifferentiated hESCs for removal of residual teratoma (tumor)-initiating cells from therapeutic preparations, to ensure transplantation safety.
  • We have made substantial progress toward achieving these goals. First, we discovered that the initial differentiation of hESCs occurs through only 4-5 different progenitor types, of which one is destined to give rise to heart lineages. We purified this population using four novel cell surface markers (ROR2, PDGFRα, KDR, and CD13), and found a significant enrichment of cardiomyocyte clones in colony formation assays that we developed. This subset also expressed particularly high levels of cardiac genes and was receptive to further differentiation into beating cardiomyocytes or vascular endothelial cells. When transplanted into immunodeficient mice these progenitors differentiated into ventricular myocytes and vascular endothelial cells. We have also successfully developed a human fetal heart xenograft model to test hESC-derived cardiomyocyte stem/progenitor cells in human heart tissue for engraftment and function.
  • Second, we have optimized cell culture conditions and cell surface markers to sort hematopoietic progenitors derived from hESCs. In doing so, we have mapped the earliest stages of hematopoietic specification and commitment from a bipotent hematoendothelial precursor. Our culture conditions drive robust hematopoietic differentiation in vitro but these hESC-derived hematopoietic progenitors do not achieve hematopoietic engraftment when transplanted in mouse models. Furthermore, we overexpressed the anti-apoptotic protein BCL2 in hESCs, and discovered a significant improvement in viability upon single cell sorting, embryoid body formation, and in cultures lacking serum replacement. Moving forward, we feel the survival advantages exhibited by this BCL2-expressing hESC line will improve our chances of engrafting hESC-derived hematopoietic stem/progenitor cells.
  • Third, we identified a cocktail of 5 commercial and 1 novel mAbs that enable specific identification of human pluripotent cells (hESCs and induced pluripotent cells). We have found combinations of 3 pluripotency surface markers that can remove all teratoma-initiating cells from differentiated hESC and induced pluripotent stem cell (iPSC) populations prior to transplant. While these combinations can vary depending on the differentiation culture, we have generated a simple, easy-to-follow protocol to remove all teratogenic cells from large-scale differentiation cultures.
  • In summary, we accomplished most of the goals stated in our original proposal. We successfully achieved cardiac engraftment of an hESC-derived cardiomyocyte progenitor using a novel human heart model of engraftment. While we unfortunately did not attain hematopoietic engraftment of hESC-derived cells, we are exploring a strategy to address this. Our research has led to four manuscripts: one on the protective effects of BCL2 expression on hESC viability and pluripotency (published in PNAS, 2011), another describing markers of pluripotency and their use in depleting teratogenic potential in differentiated PSCs (accepted for publication in Nature Biotechnology), and two submitted manuscripts, one describing a novel xenograft assay to test PSC-derived cardiomyocytes for functional engraftment and the other describing the earliest fate decisions downstream of a PSC.

Improving microenvironments to promote hematopoietic stem cell development from human embryonic stem cells

Funding Type: 
SEED Grant
Grant Number: 
RS1-00420
ICOC Funds Committed: 
$577 037
Disease Focus: 
Blood Disorders
Stem Cell Use: 
Embryonic Stem Cell
Public Abstract: 
Hematopoietic stem cells (HSC) have been used successfully to cure various life-threatening blood diseases. Yet, matching HSCs are not available for every patient. Human embryonic stem cells (hESC) may provide an unlimited source of HSCs for therapeutic use. However, hESC derived hematopoietic cells do not develop properly in those culture conditions that are currently used, and thereby their function is impaired. Hematopoietic cells that are derived from human ES cells lack the ability to self-renew, which is a prerequisite for the ability to generate blood cells for the individual’s lifetime. HSCs can only develop and function normally if they receive correct signal from their microenvironment, the stem cell niche. The goal of our proposal is take advantage of our knowledge of development of hematopoietic stem cells during embryogenesis, and mimic the environments where HSCs normally develop to provide the cues for proper HSC development in culture. We will attempt to mimic physiological HSC niches by deriving stroma lines from human placentas, which we have shown to be an important site for HSC development. We will further modify these lines by adding regulatory molecules that are known to aid HSC self-renewal, or inhibit molecules that might promote premature differentiation. Alternatively, we will use placental villi as a niche where ES cell derived hematopoietic cells could develop during culture. Subsequently, hESC derived cells are tested in animal models where human hematopoietic tissues have been implanted to provide an optimal environment for human HSCs to function. These studies are expected to shed light on the mechanisms that enable human HSCs to establish and maintain self-renewal ability and multipotency, and improve the differentiation of hESCs towards functional HSCs, which could be used to treat leukemias, other cancers, and inherited disease of the blood and immune system. To ensure hESC lines derived in different conditions respond in a similar way to these developmental cues, non-federally approved lines have to be used in this study, and thus governmental funding is not attainable for this project {REDACTED}.
Statement of Benefit to California: 
We aim to develop hematopoietic stem cells (HSC) from human ES cells (hESC) for ultimate theraoutic use for blood diseases. Only up to 50% of the patients that could be cured by HSC transplantation are able to receive this treatment, as matching donors are not available for every patient. If functional HSCs could be generated from hESCs, patients in California that suffer from leukemias or other acquired or inherited diseases of the blood and immune system could be treated. We aim to develop novel approaches to differentiate HSCs from hESCs by mimicking the physiological niches where human HSCs normally develop. Through these studies, we aim to understand what the critical properties in HSC microenvironment are that signal for HSCs to preserve their functionality. Identification of the regulatory cues that alter HSC fates between self-renewal and differentiation might also lead to innovative discoveries that could be developed into biotechnological or pharmaceutical products in California, thereby improving the industry and economy in California.
Progress Report: 
  • Our goal has been to improve the microenvironment where human embryonic stem cells (hESC) differentiate in order to generate functional hematopoietic stem/progenitor cells (HS/PC) in culture, with the ultimate goal to use these HS/PCs for the treatment of leukemias and other blood diseases. We have tested various human and mouse stroma lines for their ability to support expansion of multipotential human HS/PCs as well as hematopoietic specification from hESCs. So far mouse mesenchymal stem cells (MSC) have proven to provide the best supportive ability for human hematopoiesis. By combining embryoid body differentiation and co-culture on mouse MSC stroma, we have succesfully generated HS/PCs that phenotypically resemble bona fide human HSCs (CD34+CD38-CD90+CD45+). However, so far their differentiation ability has been biased toward myeloerythroid cells, with poor ability to generate B-cells in culture. Based on microarray data that we obtained from a related project supported by the CIRM New Faculty Award, we have identified molecular programs that are defective in hES derived HS/PCs. Future efforts will be directed in modifying the culture microenvironment as well as the cell intrinsic regulatory machinery in hES derived HS/PCs in order to improve their differentiation and self-renewal potential.
  • Our goal has been to improve the microenvironment where human embryonic stem cells (hESC) differentiate in order to generate functional hematopoietic stem/progenitor cells (HS/PC) in culture, with the ultimate goal to use these HS/PCs for the treatment of leukemias and other blood diseases. We have optimized a two step differentiation protocol that combines embryoid body differentiation and subsequent stroma co-culture to generate HS/PCs that exhibit the same phenotype as HSCs obtained from human hematopoietic tissues (CD34+CD38-CD90+CD45+). However, our findings indicate that the hESC derived HS/PCs have restricted developmental potential as compared to fetal liver or cord blood derived HS/PCs, and they senesce prematurely in culture, and are unable to generate B-cells . Our functional and molecular studies suggest that hES-derived HS/PCs resemble closely lineage-restricted progenitors found early in development in human hematopoietic tissues. Our recent studies have focused on exploring the possibility that another precursor that develops in the embryoid bodies could have lymphoid potential when placed in an appropriate microenvironment. Our preliminary data suggests that development of T-lymphocytes from hESCs in vitro may be feasible. Our future work will continue to focus on generating fully functional HSCs by improving the in vitro microenvironment where HS/PCs develop, and/or programming HSC transcriptional program using inducible lentiviral vectors.

Generation of long-term cultures of human hematopoietic multipotent progenitors from embryonic stem cells

Funding Type: 
SEED Grant
Grant Number: 
RS1-00280
ICOC Funds Committed: 
$538 211
Disease Focus: 
Blood Disorders
Stem Cell Use: 
Embryonic Stem Cell
oldStatus: 
Closed
Public Abstract: 
For many therapeutic reasons it is important to have available large numbers of blood cells. However, it is difficult to generate large numbers of specialized blood cells that have the ability to neutralize autoimmunity and response to tumor cell growth. In this study we would develop a technique that would allow the production of large numbers of different types of blood cells from human embryonic stem cells. For example, a subset of white blood cells, called dendrititc cells, is currently manipulated in the laboratory in a manner that allows them to attack cancer cells. The same cells also are altered in the laboratory to counter-act the development of autoimmune diseases. A problem with these experiments is that it is difficult to isolate large numbers of these cells, since they are relatively rare. With the technology that is described in this grant application we would be able to generate large numbers of such cells in the laboratory using as a starting point, human embryonic stem cells.
Statement of Benefit to California: 
In this study we would develop an approach that would allow the production of large numbers of different types of blood cells from human embryonic stem cells. For example, a subset of white blood cells, called dendrititc cells, is currently manipulated in the laboratory in a manner that allows them to attack cancer cells. The same cells also are altered in the laboratory to counter-act the development of autoimmune diseases. A problem with these experiments is that it is difficult to isolate large numbers of these cells, since they are relatively rare. With the technology that is described in this grant application we would be able to generate large numbers of such cells in the laboratory using as a starting point, human embryonic stem cells. The approach is novel and straightforward and could be applied immediately once it has been established.
Progress Report: 
  • A prominent subset of white blood cells, named CD4 helper T cells, are critical in modulating the immune response against viral and bacterial pathogens. During HIV infection, the CD4 compartment is selectively reduced, suppressing the activity and response of cytolytic CD8 T cells, needed to abolish cells infected with the virus. Pharmaceutical therapies have been developed but they are not consistently effective and multidrug resistant viral strains are increasingly prevalent. Similarly, in vitro manipulated human dendritic cells are now being explored to tolerize against autoimmune disease or to stimulate antitumor responses. However, the number of dendritic cells that can be isolated form patients using current technologies is small. Consequently, different approaches need to be developed to enhance T cell reconstitution. In principle, multipotent hematopoietic progenitors could be derived from hESCs without long-term in vitro culture. A drawback is that the number of human hematopoietic progenitors derived from human ES cell cultures is limited using current culture conditions. Consequently, a subset of studies involving in vitro manipulated human cells would be difficult to perform. The transduction of human progenitor cells can be achieved using a tissue culture system in which human cord blood progenitors are differentiated in the presence of stromal cells that express the Notch ligand DL-1 towards the T cell lineage. However, the efficiency by which human progenitor cells differentiate into the T lineage cells is low. In the original application we proposed to develop a novel strategy that would permit the generation of large numbers of human T cell progenitors (up to 109) from human hematopoietic stem cells. To accomplish this objective we would target a critical regulator of early hematopoieisis, named E2A. Indeed during the two years period funded by CIRM we have demonstrated that murine hematopoietic progenitors that overexpress an inhibitor of E2A, named Id2, can be grown indefinitely in culture without losing their ability to generate many different types of white blood cells in the laboratory. This strategy is unconventional since it would permit the growth and isolation of large numbers of T cell progenitors, which has not been achieved so far by conventional culture conditions. We will continue these studies and use the same strategy to establish a long-term culture of human hematopoietic progenitor cells. If successful the approach would enable clinicians to reconstitute the hematopoietic compartments of patients carrying invading pathogens, including HIV infected patients, with large numbers of T cells that either express either a wild-type TCR repertoire or TCRs with specificities directed against invading pathogens. I expect this to succeed since we have already achieved this objective using murine progenitors as demonstrated during the past two years using funds obtained form the CIRM.

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