Blood Disorders

Coding Dimension ID: 
278
Coding Dimension path name: 
Blood Disorders
Funding Type: 
Research Leadership
Grant Number: 
LA1-06917
Investigator: 
Institution: 
Type: 
PI
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.

Progress Report: 
  • Adoptive immunotherapy with functional T cells is a potentially effective therapeutic strategy against various types of cancers and viral infections. A major challenge however lies with the “exhaustion” (loss of cytotoxic and proliferative capacities) of antigen-specific T cells during expansion in culture. For an effective adoptive immunotherapy, what we need is not the "exhausted" T cells, but large number of "young and active" CD8+ T cells that can kill tumors or virus infected cells efficiently. To address this issue, we generated induced pluripotent stem cells (iPSCs) from EBV-specific CD8+ T cells from an EBV-infected patient. We then redifferentiated these iPSCs into CD8+ T cells or we like to call them “rejuvenated” T cells since they are newly generated and highly proleferative. These rejT cells possessed antigen-specific killing activity and exhibited TCR gene rearrangement patterns identical to those of the original T cell clone from the patient. In order to confirm in vivo efficacy of these rejT cell, we innoculated EBV-induced tumors into immunodeficient mice and after confimation of tumor growth, we injected these rejT cells. Results indicated that these rejT cells eliminated tumors more efficiently than the original EBV-specific CD8+ T cells, thus confirming in vivo efficacy of these T cells.
  • Another aspect we worked on is generation of a functional organ in livestock animals. In the past, we have demonstrated generation of rat pancreas in mouse utilising a method called "blastocyst complementation". In ancillary work, we successfully generated exogenous-pig pancreata using the same principle. Whilst these studies prepared us to examine the feasibility of generating human PSC-derived pancreata in pancreatogenesis-disabled pigs, some ethical issues on making such “admix chimeras” have yet to be solved. A part of the concern comes from the possibility that human iPSC-derived cells contribute to neural or germ cells in chimeric animals. To overcome this issue, we attempted to restrict differentiation of PSC-derived cells into endodermal organs by introducing a gene that is important for the development of internal organs. When the expression of this gene was induced after transfer of embryo to foster mother, differentiation of ES-derived cells were directed toward interenal organs avoiding contribution of those cells in germ cells, skin and nervous systems. We termed this type of organ generation as "Targeted organ generation" and this should, in principle, reduce the ethical concern when making human-livestock chimeras.
  • In addition, we found that the inhibition of nuclear translocation of a molecule called b-CATENIN enhances conversion of mouse EpiSCs (non-chimera forming) to naive-like PSCs (chimera forming). Since most human ES/iPSCs are considered EpiSCs and non-chimera forming, the finding is of importance for the generation of human organs in ivestock animals.
Funding Type: 
Tools and Technologies III
Grant Number: 
RT3-07692
Investigator: 
ICOC Funds Committed: 
$1 416 600
Disease Focus: 
Blood Disorders
Stem Cell Use: 
Adult Stem Cell
Public Abstract: 

Tens of thousands of patients need bone marrow transplants (BMT) every year, some for bone marrow (BM) cancers and some for inherited diseases such as sickle cell anemia and thalassemia, but many lack a BM donor. African Americans, Asian Americans, and people of Hispanic descent are more likely than others to lack a stem cell donor.

BMTs provide hematopoietic (blood) stem and progenitor cells (HS/PCs) that replace the patient’s diseased BM with healthy BM. The new BM provides all the circulating blood cells throughout life.

Many BMTs use HS/PCs that do not come from the BM. One such ‘other’ source is umbilical cord blood (UCB). UCB HS/PCs have many advantages over other HS/PC sources (i.e., BM or peripheral blood). For example, we can easily obtain UCB HS/PCs without any risk to the donor, and we can keep the cells stored in freezers to be available when a patient needs them. However, most UCB samples contain too few HS/PCs to be used to treat people.

Expanding the number of HS/PCs in UCB samples will increase the number of clinically usable UCB samples, offering new hope for thousands of patients who currently lack a donor. We previously screened >120,000 compounds for their ability to expand UCB HS/PCS, and identified a short list of lead candidates. This grant will fund the next step in our effort to develop a novel, clinically-useful UCB HS/PC expansion protocol. Successful completion of this proposal will result in life-saving treatment for thousands of patients.

Statement of Benefit to California: 

Our proposal seeks to establish a novel method to expand umbilical cord blood hematopoietic stem/progenitor cells (HS/PCs) to make bone marrow transplants (BMTs) available to thousands of patients who currently lack a stem cell donor. The benefits to California are wide-ranging:
• Grow California’s skilled workforce and create jobs: This project will train scientists in stem cell research and technology, and our success will attract more talent from outside California.
• Increase innovation: This proposal is highly translational, with a goal to move rapidly from bench to bedside. However, our research will also provide basic insights into stem cell biology that can be applied by other scientists to help patients more broadly.
• Enhancing the medical treatment of California residents: Compounds that expand UBC HS/PCs have the potential to improve clinical benefit and reduce health care costs by increasing the success rate of stem-cell transplants. Given California’s diverse ethnic population, we have many patients who need a BMT yet lack a donor, so our residents will directly benefit from our success.
• Attracting venture capital and commercialization: We aim to develop technology that will be highly attractive to the biotechnology industry. We have identified GE as a partner to commercialize our reagents and processes. Furthermore, commercially viable compounds will attract venture capital to fund cell therapies and create new biotech jobs for the California economy.

Funding Type: 
Alpha Stem Cell Clinics
Grant Number: 
AC1-07659
Investigator: 
Name: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$8 000 000
Disease Focus: 
Blood Disorders
Blood Cancer
Cancer
HIV/AIDS
Solid Tumor
Stem Cell Use: 
Adult Stem Cell
Public Abstract: 

As the largest provider of bone marrow cell transplants in California, and the second largest in the nation, our institution has great expertise and an excellent record of safety in the delivery of stem cell treatments. We now propose to create the Alpha Clinic for Cell Therapy and Innovation (ACT-I) in which new, state-of-the-art, stem cell treatments for cancer and devastating blood-related diseases will be conducted and evaluated. As these experimental therapies prove to be effective, and become routine practice, our ACT-I Program will serve as the clinical center for delivery of these treatments. ACT-I will be an integral part of our Hematologic Malignancy and Stem Cell Transplantation Institute, placing it in the center of our institutional strengths, expertise, infrastructure and investment over the next decade. To move quickly once the CIRM award is made, ACT-I can be launched within our institution’s Day Hospital, a brand new, outpatient blood stem cell transplantation center opened in late 2013 with California Department of Health approval for 24 hour a day operation. This will ensure that ACT-I will have all the clinical and regulatory expertise, trained personnel, state-of-the-art facilities and other infrastructure in place to conduct first-in-human clinical trials and to deliver future, stem cell-based therapies for cancer and blood-related diseases, including AIDS. When our new Ambulatory Treatment Center is complete in 2018, it will double our capacity for patient visits and allow for expansion of the ACT-I pipeline of new stem cell products in a state-of-the-art facility.

Beyond our campus, we operate satellite clinics covering an area that includes urban, suburban and rural sites. More than 17.7 million people live in this area, and represent some of the greatest racial and ethnic diversity seen in any part of the country. Our ACT-I is prepared to serve a significant, diverse and underserved portion of the population of California.

CLINICAL TRIALS. Our proposal has two lead clinical trials that will be the first to be tested in ACT-I. One will deliver transplants of blood stem cells that have been modified to treat patients suffering from AIDS and lymphoma. The second will use neural stem cells to deliver drugs directly to cancer cells hiding in the brain. These studies represent some of the new and exciting biomedical technologies being developed at our institution. In addition to the two lead trials, we have several additional clinical studies poised to use and be tested in this special facility for clinical trials. In summary, ACT-I is well prepared to accommodate the long list of clinical trials and begin to fulfill the promise of providing new stem cell therapies for the citizens of California.

Statement of Benefit to California: 

California’s citizens voted for the California Stem Cell Research and Cures Act to support the development of stem cell-based therapies that treat incurable diseases and relieve human suffering. To achieve this goal, we propose to establish an Alpha Clinic for Cellular Therapies and Innovation (ACT-I) as an integral part of our Hematological Malignancies and Stem Cell Transplantation Institute, and serve as the clinical center for the testing and delivery of new, cutting-edge, cellular treatments for cancer and other blood-related diseases. Our institution is uniquely well-suited to serve as a national leader in the study and delivery of stem cell therapeutics because we are the largest provider of stem cell transplants in California, and the second largest in the country. According to national benchmarking data, our Hematopoietic Cell Transplantation program is the only program in the nation to have achieved survival outcomes above expectation for each of the past nine years. This program currently offers financially sustainable, research-driven clinical care for patients with cancer, HIV and other life-threatening diseases. CIRM funding will allow the ACT-I clinic to ramp up quickly, drawing upon institutionally established protocols, personnel and infrastructure to conduct first-in-human clinical trials for assessment of efficacy. As CIRM funding winds down, ACT-I will have institutional support to offer proven cellular therapeutics to patients. The lead studies at the forefront of the ACT-I pipeline of clinical trials focus on treatments for HIV-1 infection and brain tumors, two devastating and incurable conditions. These first trials are closely followed by a robust queue of other stem cell therapeutics for leukemia, lymphoma, prostate cancer, brain cancers and thalassemia.

Our long list of proposed treatments addresses diseases that have a major impact on the lives of Californians. Thalassemia is found in up to 1 in 2,200 children born in California; prostate cancer affects 211,300 men, and HIV-1 infection occurs in 111,000 of our citizens. From 2008 to 2010, 6,705 Californians were diagnosed with brain cancers, 4,580 of whom died. In considering hematological malignancies during this same period, 2,800 patients were diagnosed with Hodgkin lymphoma (416 died), 20,351 with non-Hodgkin lymphoma (6,241 died), 13,358 with leukemia (6,961 died), 3,900 with acute myelogenous leukemia (2,972 died), 2,129 with acute lymphoblastic leukemia (648 died) and 4,198 with chronic lymphocytic leukemia (1,271 died). Standard of care fails in many cases; mortality rates for patients with hematological malignancies range from 25% to 76%. Successful stem cell therapeutics hold the promise to reduce disease-related mortality while improving disease-related survival and quality of life for the citizens of California, and for those affected by these diseases worldwide.

Funding Type: 
Tools and Technologies III
Grant Number: 
RT3-07763
ICOC Funds Committed: 
$1 382 400
Disease Focus: 
Blood Disorders
Collaborative Funder: 
Australia
Stem Cell Use: 
Embryonic Stem Cell
Cell Line Generation: 
Embryonic Stem Cell
Public Abstract: 

Our goal is to develop tools that address major bottlenecks that have prevented the generation of blood forming stem cells in culture for therapeutic use. To help overcome these bottlenecks, we will generate a suite of human embryonic stem cell reporter lines that can be used to monitor key milestones in blood stem cell development. These lines will serve as tools to identify factor combinations to improve the in vitro differentiation of hESCs to functional blood stem cells. Once individual lines have been validated, lines that contain multiple fluorescent reporters will be generated, and a multi factor screen will be performed to optimize conditions that induce these blood stem cell regulators. To track the location and quantity of transplanted cells in recipient small animal model, we will generate hESC lines with in vivo reporter system that combines bioluminescent or PET imaging, and serum-based assay. Our in vivo tracking tools will be broadly relevant and not restricted to studying the in vivo biology of blood forming cells. These tools will help translate the promise of stem cells to cell based therapies to treat human disease.

Statement of Benefit to California: 

This project will help improve California economy as many of the vendors used for reagents and supplies are located in California. This project will also help create and maintain jobs for skilled personnel and helps train post-doctoral fellows who will become the next generation of stem cell scientists. The long-term goal of this project is to improve in vitro differentiation protocols to create transplantable blood forming stem cells for therapeutic use. If we, or others who will use our reporter lines generated in this study, achieve this goal, there will be new, theoretically unlimited sources of HLA-matched or patient specific blood stem cells that can be used for treating many serious blood diseases, including leukemias and inherited immunodeficiencies or anemias. Availability of patient specific blood stem cells for transplantation would be a major benefit in California, as there is currently limited availability of suitable bone marrow donors for individuals from mixed ethnic backgrounds.

Funding Type: 
Early Translational IV
Grant Number: 
TR4-06809
Investigator: 
Type: 
PI
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.

Progress Report: 
  • Hemophilia B is a bleeding disorder caused by the lack of FIX in the plasma and affects 1 in 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. Gene therapy with viruses is beset with problems of safety and increased immunogenicity. 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 will generate iPSCs from hemophilic patients that will be genetically corrected by inserting FIX coding DNA. After correction, we will differentiate these iPSCs into liver cells which will then be transplanted into our mouse model of hemophilia that can accept human hepatocytes and allow 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 will serve as a proof-of-concept for the treatment of other liver diseases.
  • With this long term aim, during the first year of the project, we have procured two hemophilic patient samples and two control samples from our collaborators. We have successfully generated iPSCs with no long-term genomic changes. We are currently working towards identifying the mutations in the patients that were responsible for the disease. Our efforts are presently directed towards correcting the mutations in the patient derived iPSCs so that they can now produce a functional FIX protein.
Funding Type: 
Strategic Partnership I
Grant Number: 
SP1-06477
Investigator: 
Institution: 
Type: 
PI
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.

Funding Type: 
New Faculty Physician Scientist
Grant Number: 
RN3-06479
Investigator: 
ICOC Funds Committed: 
$3 084 000
Disease Focus: 
Blood Disorders
Blood Cancer
Cancer
Stem Cell Use: 
iPS Cell
Directly Reprogrammed Cell
Cell Line Generation: 
Directly Reprogrammed Cell
oldStatus: 
Active
Public Abstract: 

The current roadblocks to hematopoietic stem cell (HSC) therapies include the rarity of matched donors for bone marrow transplant, engraftment failures, common shortages of donated blood, and the inability to expand HSCs ex vivo in large numbers. These major obstacles would cease to exist if an extensive, bankable, inexhaustible, and patient-matched supply of blood were available. The recent validation of hemogenic endothelium (blood vessel cells lining the vessel wall give rise to blood stem cells) has introduced new possibilities in hematopoietic stem cell therapy. As the phenomenon of hemogenic endothelium only occurs during embryonic development, we aim to understand the requirements for the process and to re-engineer mature human endothelium (blood vessels) into once again producing blood stem cells (HSCs). The approach of re-engineering tissue specific de-differentiation will accelerate the pace of discovery and translation to human disease. Engineering endothelium into large-scale hematopoietic factories can provide substantial numbers of pure hematopoietic stem cells for clinical use. Higher numbers of cells, and the ability to grow cells from matched donors (or the patients themselves) will increase engraftment and decrease rejection of bone marrow transplantation. In addition, the ability to program mature lineage restricted cells into more primitive versions of the same cell lineage will capitalize on cell renewal properties while minimizing malignancy risk.

Statement of Benefit to California: 

Bone marrow transplantation saves the lives of millions with leukemia and other diseases including genetic or immunologic blood disorders. California has over 15 centers serving the population for bone marrow transplantation. While bone marrow transplantation can be seen as a standard to which all stem cell therapies should aspire, there still remains the difficulty of finding matched donors, complications such as graft versus host disease, and the recurrence of malignancy. While cord blood has provided another donor source of stem cells and improved engraftment, it still requires pooling from multiple donors for sufficient cell numbers to be transplanted, which may increase transplant risk. By understanding how to reprogram blood vessels (such as those in the umbilical cord) for production of blood stem cells (as it once did during human development), it could eventually be possible to bank umbilical cord vessels to provide a patient matched reproducible supply of pure blood stem cells for the entire life of the patient. Higher numbers of cells, and the ability to grow cells from matched donors (or the patients themselves) will increase engraftment and decrease rejection of bone marrow transplantation. In addition, the proposed work will introduce a new approach to engineering human cells. The ability to turn back the clock to near mature cell specific stages without going all the way back to early embryonic stem cell stages will reduce the risk of malignancy.

Progress Report: 
  • We aim to understand how blood stem cells develop from blood vessels during development. We are also interested in learning whether the blood-making program can be turned back on in blood vessel cells for blood production outside the human body. During the past year we have been able to extract and culture blood vessel cells that once had blood making capacity. We have also started experiments that will help uncover the regulation of the blood making program. In addition, we have developed tools to help the process of understanding whether iPS technology can "turn back time" in mature blood vessels and turn on the blood making program.
  • We aim to understand how blood stem cells develop from blood vessels during development. We are also interested in learning whether the blood-making program can be turned back on in blood vessel cells for bloodproduction outside the human body. During the past year we have made progress in understanding early human hematopoiesis such that we have designed new tools that may enable us to try and generate hematopoietic cells in culture. We have also gained ground in refining our screening strategy that we hope to adapt for finding new regulators of blood development that can be used for culturing hematopoietic stem cells.
Funding Type: 
Early Translational I
Grant Number: 
TR1-01273
Investigator: 
Type: 
PI
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.
Funding Type: 
Transplantation Immunology
Grant Number: 
RM1-01733
Investigator: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$1 403 557
Disease Focus: 
Blood Disorders
Immune Disease
Muscular Dystrophy
Stem Cell Use: 
Adult Stem Cell
oldStatus: 
Active
Public Abstract: 

Blood and immune cells originate and mature in the bone marrow. Bone marrow cells are mixtures of blood cells at different stages of development, and include rare populations of blood-forming stem cells. These stem cells are the only cells capable of generating the blood system for the life of an individual. Bone marrow transplants (BMT) have been performed > 50 years, to replace a diseased patient’s blood system with that of a donor. Unfortunately, BMT have associated dangers which make the procedure high risk. Major risks include a syndrome called graft-versus-host disease (GvHD) which results when the donor’s mature blood cells attack the organs of the host, and toxicity from the treatments (radiation and chemotherapy) required to permit the donor cells to take in the recipient. These risk factor limit the use of BMT to only immediate life-threatening diseases.

If made safer, BMT could cure many other debilitating diseases. In addition to being curative of blood cancers and non-malignant blood diseases (such as sickle-cell anemia), these transplants can cure autoimmune diseases, such as juvenile (type I) diabetes and multiple sclerosis. In addition, simultaneous BMT with organ transplants induces “tolerance” to the new organ, meaning the recipient will not reject the graft because the new blood system provides continuous proteins to re-train the recipient immune system not to attack it. This establishment of tolerance eliminates the need for drugs that suppress the immune system.

In efforts to make BMT safer, our research has focused on isolating the blood stem cells away from the other bone marrow cells because transplants of pure stem cells do not cause GvHD. We developed the methods to purify the blood stem cells from mouse and human blood forming sources and showed in mice that transplants of blood stem cells can cure autoimmune disease and induce tolerance to solid organ transplants. However, this technology has not been tested in human clinical trials because safer methods must be developed that permit the stem cells to engraft in recipients.

Our studies in mice show that we can replace the toxic drugs and radiation used to prepare recipients for BMT with non-toxic proteins that target the cells responsible for rejection of blood stem cells. The goal of this study is to translate this technology from mice to patient clinical trials. If successful, the studies will open the door to the use of blood stem cell transplants to the many thousands of patients who could benefit from this approach. The science behind achieving blood stem cell engraftment by the methods we propose look toward the future when blood stem cells and other tissues will be developed from pluripotent stem cells (ES, NT and iPS). We envision that the blood stem cells will induce tolerance to tissues derived from the same pluripotent stem cell line, in the same way that adult blood stem cells induce tolerance to organs from the same living donor.

Statement of Benefit to California: 

The science and the preclinical pathway to induce human immune tolerance in patients with degenerative diseases so that new blood and tissue stem cells can regenerate their lost tissues: For stem cell biology to launch the era of regenerative medicine, stem cells capable of robust and specific regeneration upon transplantation must be found, and methods for safe patient administration must be developed. In the cases where cell donation cannot come from the host, immune responses will reject the donor stem cells. Successful transplants of blood-forming stem cells (HSC) leads to elimination immune cells that reject organ grafts from donors. While bone marrow or cord blood transplants contain immune cells called T cells that will attack the host in a potentially lethal graft against host immune reaction, purified HSC do not do this. Pluripotent stem cells (ES, NT, iPS) can make all cell types in the body and provide a shortcut to find tissue and organ stem cells. Just as co-transplants of adult HSC prevent rejection of organs from the same donor, co-transplants of HSC derived from pluripotent cells should protect tissues derived from the same pluripotent line. Attack by a patient's blood system against one’s own organs cause the syndromes of autoimmune disease including juvenile diabetes, multiple sclerosis, and lupus. Transplanted HSC from donor mice genetically resistant to these diseases end the autoimmune attack permanently. We have in mice, substituted minimally toxic antibodies for toxic chemoradiotherapy to prepare the host for HSC transplants. Now it is time to take these advances to humans, with human immune cell and HSC-targeting antibodies.

Long-term potential benefits to the state of California and its residents: The justification for Proposition 71 was to establish in California centers of research not funded adequately in the areas of stem cell biology and regenerative medicine. This research, if successful, is the platform for the application of stem cell biology to regenerative medicine. The costs for long-term immune suppression to patients who receive organ transplants are enormous, both in terms of quality of life, even survival, and healthcare resources. Add to that the lifetime costs of insulin to treat juvenile diabetes, with the inevitable premature diseases of compromised blood vessels and organs, and the shortened lifespan of patients. Add to that the costs to lives and the healthcare system of lupus, of multiple sclerosis, of other autoimmune diseases like juvenile and adult rheumatoid arthritis and scleroderma, and of muscular dystrophy, to mention a few, and the value to Californians and people everywhere is obvious. If our studies are successful, and if the clinical trials were first done in California, our citizens will have the first chance at successful treatment. Further, if these studies are successful - new antibodies, if produced by CIRM funds, will generate royalties which eventually will return to the state.

Progress Report: 
  • The successful transplantation of blood forming stem cells from one person to another can alter the recipient immune system in profound ways. The transplanted blood forming cells can condition the recipient to accept organs from the original stem cell donor without the need for drugs to suppress their immune system; and such transplantations can be curative of autoimmune diseases such as childhood diabetes and multiple sclerosis. Modification of the immune system in these ways is called immune tolerance induction.
  • Unfortunately, the current practice of blood stem cell transplantation is associated with serious risks, including risk of death in 10-20% of recipients. It has been a long-standing goal of investigators in this field to make transplantations safer so that patients that must undergo this procedure have better outcomes, and so that patients who need an organ graft or that suffer from an autoimmune disorder can be effectively treated by this powerful form of cellular therapy. The major objectives of our proposal are to achieve this goal by developing methods to prepare patients to accept blood forming stem cell grafts with reagents that specifically target cell populations in recipients that constitute the barriers to engraftment, and to transplant only purified blood forming stem cells thereby avoiding the potentially lethal complication call graft-vs-host disease.
  • The proposal has four Specific Aims. Aims 1 and 2 focus on development of biologic agents that specifically target recipient barrier cells. Aims 3 and 4 propose to test the reagents and approaches developed in the first two aims in mouse models to induce tolerance to co-transplanted tissues and to cure animals with Type 1 diabetes mellitus or multiple sclerosis. These aims have not changed in this reporting period.
  • One parameter of success in this project is the development of one or more biologic reagents that can replace toxic radiation and chemotherapy that can be used in human clinical trials by the end of the third year of funding (Aim 2). In this regard, significant progress has been made in the last year. A reagent critical to the success of donor blood forming stem cell engraftment is one that targets and eliminates the stem cells that already reside in the recipients. Recipient blood stem cells block the ability of donor stem cells to take. In our prior mouse studies we determined that a protein (antibody) that specifically targets a molecule on the surface of blood forming stem cells called CD117 is capable of eliminating recipient blood stem cells thus opening up special niches and allowing donor stem cells to engraft. This antibody was highly effective in permitting engraftment of purified donor blood stem cells in mice that lack a functional immune system. In this application we proposed to develop and test reagents that could target and eliminate human blood forming stem cells by targeting human CD117. This year we have identified and tested such an antibody which is manufactured by a third party. This anti-CD117 antibody has been evaluated in early clinical trials for an indication separate from our proposed use and appears to be non-toxic. In mice that we generated to house a human blood system, the antibody was capable eliminating the human blood forming stem cells. We plan to pursue the use of this reagent in a clinical trial as a non-toxic way to prepare children with a disease called severe combined immunodeficiency (SCID) for transplantation. Without a transplant children with SCID will die. The use of the anti-CD117 antibody and transplantation of purified blood forming stem cells has the potential to significantly reduce the complications of such transplants and improve the outcomes for these patients. The trial will be the first step to using this form of targeted therapy and serve as a pioneering study for all indications for which a blood forming stem cell transplant is needed, including the induction of immune tolerance.
  • The transplantation of blood forming stem cells from one individual to another can alter the recipient immune system in profound ways. Transplanted blood forming cells can condition the recipient to accept organs from the original stem cell donor without the need for drugs to suppress their immune system. Such transplantations can also be curative of autoimmune diseases such as childhood diabetes and multiple sclerosis. Modification of the immune system in these ways is called immune tolerance induction.
  • The major goal of this project is to enable the use of blood forming stem cell transplantation for the purpose of immune tolerance induction without unwanted side effects. The current practice of blood stem cell transplantation is associated with serious risks, including risk of death in 10-20% of recipients due to complications of transplant conditioning and graft-versus-host disease. We aim to abolish or reduce the risks of these transplantations so that this curative form of stem cell therapy can safely treat patients who need an organ graft or who suffer from an autoimmune disorder. To achieve our goals, we proposed the development of methods to prepare patients to accept blood forming stem cell grafts with reagents that specifically target recipient cell populations that constitute the barriers to engraftment, and to transplant only purified blood forming stem cells, thereby avoiding graft-versus-host disease.
  • The proposal has four Specific Aims. Aims 1 and 2 focus on development of biologic agents that specifically target recipient barrier cells. Aims 3 and 4 propose testing the reagents and approaches developed in the first two aims in mouse models to induce tolerance to co-transplanted tissues and to cure animals with muscular dystrophy, Type 1 diabetes mellitus and multiple sclerosis. These aims have not changed in this reporting period.
  • In this reporting period, significant progress has been made in the first three aims. In prior years we identified a biologic reagent that has the potential to replace toxic radiation and chemotherapy. Radiation and chemotherapy are used in transplantation to eliminate the blood forming stem cells of recipients because recipient stem cells block the ability of donor cells to take. The novel reagent we have studied is a protein, called a monoclonal antibody, which differs from radiation and chemotherapy because it specifically targets and eliminates recipient blood stem cells. This antibody reagent recognizes a molecule on the surface of blood stem cells called CD117. In years 1 and 2 we began testing of an anti-human CD117 (anti-hCD117) antibody in mice. Mice were engrafted with human blood cells and we showed that this antibody safely and specifically eliminated the human blood forming cells. These studies were proof-of-concept that the antibody is appropriate for use in human clinical trials.
  • This last year we were awarded a CIRM Disease Team grant to move the testing of this anti-hCD117 from the experimental phase in mice to a clinical trial for the treatment of children with a disease call severe combined immunodeficiency (SCID), also known as the “bubble boy” disease. Children with SCID are missing certain types of white blood cells (lymphocytes) so they cannot defend themselves from infections. Without a transplant, children with SCID will die. The use of the anti-CD117 antibody and transplantation of purified blood forming stem cells has the potential to significantly reduce the complications of such transplants and improve the outcomes for these patients. The use of the anti-CD117 antibody and transplantation of purified blood forming stem cells has the potential to significantly reduce the complications of such transplants and improve the outcomes for these patients. The trial will be the first step to using this form of targeted therapy and serve as a pioneering study for all indications for which a blood forming stem cell transplant is needed, including the induction of immune tolerance.
  • In the last year we have moved forward with the purification of skeletal muscle stem cells based upon labeling and sorting of primitive muscle cells that express an array of molecules on the cell surface. We have also transplanted a special strain of mice (mdx) that are a model for muscular dystrophy with blood forming stem cells from normal mouse donors. In the coming year we will perform simultaneous transplants of blood forming stem cells and skeletal muscle stem cells from normal donor mice into the mdx mice. We will determine if the blood stem cells permit the long-term survival of the muscle stem cells in recipients transplanted across histocompatibility barriers. Our ultimate goal is to achieve long-term recovery of muscle cell function in the recipients of these co-transplantations.
  • The transplantation of blood forming stem cells from one individual to another is widely used to treat patients with otherwise incurable cancers. Because such transplantations alter the recipient immune system in profound ways there are many other applications for this powerful form of therapy. The studies proposed in this grant focused on the use of blood stem cell transplantation for the purpose of immune tolerance induction. Tolerance induction in this setting means that transplantation of blood stem cells trains the body of a recipient to accept organs from same stem cell donor without the need for drugs to suppress their immune system. Blood stem transplantations can also reverse aberrant immune responses in individuals with autoimmune diseases such as childhood diabetes and multiple sclerosis.
  • In this project we sought to develop new ways to perform blood stem cell transplants to make the procedure safer and therefore more widely useable for a broad spectrum of patients. Transplants can be dangerous and sometimes fatal. Serious complications are caused by the toxic chemotherapy or radiation which are used to permit stem cells to engraft, and by a syndrome called graft-versus-host disease. Our research has aimed to replace the toxic treatments by testing novel reagents that more specifically target and eliminate the cells in recipients that constitute the barriers to stem cell engraftment. Furthermore, we perform transplantations of purified blood forming stem cells, and thus are able to avoid the problem of graft-versus-host disease which is caused by non-stem cell “passenger” immune cells in the donor grafts.
  • The proposal has four Specific Aims. Aims 1 and 2 focus on development of biologic agents that specifically target recipient barrier cells. Aims 3 and 4 propose testing the reagents and approaches developed in the first two aims in mouse models to induce tolerance to co-transplanted tissues and to cure animals with muscular dystrophy, Type 1 diabetes mellitus and multiple sclerosis. These aims have not changed in this reporting period.
  • Our prior reports highlighted our progress in Aim 2, which is now complete. Aim 2 focused on the identification and testing of an antibody directed against a molecule called CD117 present on surface of human blood stem cells. We demonstrated that this antibody can safely target and eliminate human blood stem cells in mice that had been previously engrafted with human cells. Based upon these studies we were awarded a CIRM Disease Team Grant, which will test this anti-human CD117 antibody in a clinical trial for the treatment of children with severe combined immune deficiency (SCID), also known as the “bubble boy” disease. Children with SCID are missing certain types of white blood cells (lymphocytes) so they cannot defend themselves from infections. Without a transplant, SCID patients usually die before the age of two. Our proposed clinical study has the potential to significantly improve the success of transplants for these patients. This clinical trial will be a first to test a reagent that specifically targets recipient stem cells to clear niche space and allow replacement therapy by healthy donor stem cells.
  • In the last year we have continued to make significant progress on Aims 1, 3 and 4. Aim 1 proposed to study how to improve blood stem cell engraftment using novel agents in mice that have intact immune systems. The anti-CD117 antibody discussed above works well in recipients that lack lymphocytes but not recipients with normal immune function. We have tested the anti-CD117 antibody in mice that lack more defined lymphocyte subsets to narrow down which lymphocyte type must be neutralized or eliminated. We have also tested novel reagents that inhibit the activity of specific immune cells and observed a stronger effect of the anti-CD117 antibody when co-administered with these reagents. For Aims 3 and 4, we have successfully achieved our goal of performing blood stem cell transplants that result in the stable mixing of blood cells between donor and recipients (called partial chimerism). For Aim 3, recipients are from a specialized mouse strain that models muscular dystrophy (MDX mice). We have transplanted purified skeletal muscle stem cells (SMSC) and observed engraftment of SMSC in MDX mice injected with genetically-matched SMSC. The next step is to test if co-transplants of blood stem cells plus SMSC from genetically mismatched donors will permanently engraft and expand in MDX recipients. For Aim 4, two mouse models are studied: (1) NOD mice which model childhood diabetes, and (2) mice that develop multiple sclerosis. We can successfully block the progression of disease in these animals with blood stem cell transplants. Our next steps are to apply the therapies developed in Aim 1 to these disease models. In the post-award period we will continue to carry out studies testing the novel approaches developed here in models of tolerance induction.
Funding Type: 
Transplantation Immunology
Grant Number: 
RM1-01730
Investigator: 
Type: 
PI
ICOC Funds Committed: 
$958 808
Disease Focus: 
Blood Disorders
Stem Cell Use: 
Adult Stem Cell
Cell Line Generation: 
Adult Stem Cell
oldStatus: 
Closed
Public Abstract: 

One of the great promises of stem cell research is that it will one day be possible to prepare replacement cells or organs from stem cells such as embryonic stem cells, which can be transplanted to patients to substitute for diseased or defective patient tissues or organs. Unfortunately, the immune system reacts against, and rejects, transplanted tissues that are not perfectly matched with the recipient. A promising approach around this problem is a two step procedure, in which a patient is first transplanted with blood stem cells of a specific type, and later with replacement tissues or cells derived from the same embryonic stem cells as the blood stem cells. If the blood cell transplant is successful, the patient’s blood cells will forever after be composed of a mixture of their own blood cells and the donor blood cells (“chimerism”). It is known that blood cell chimerism induces the recipient to be accept diverse types of grafts of the same source as the blood cells. Thus, the blood cell graft prepares the recipient to accept other types of grafts derived from the same stem cells. Unfortunately, blood stem cell grafts are themselves subject to a specific type of immune rejection, mediated by natural killer (NK) cells. Hence, successful application of the two step procedure requires the development of methods to prevent NK cells from rejecting blood cell grafts.
We have developed evidence that NK cells can be induced to become tolerant of mismatched blood cell grafts. We propose studies to develop a general procedure to induce tolerance of a recipient’s NK cells to mismatched blood cell grafts. Using an experimental model, we will test whether the procedure facilitates transplantation of blood cells derived from embryonic stem cells, the generation of blood cell chimerism, and the subsequent transplantation of other tissues in a two step procedure.

Statement of Benefit to California: 

The proposed research is designed to provide novel methods to facilitate therapeutic transplantation of stem cell derived cells and tissues to patient’s suffering from numerous disorders and diseases. Such approaches will ultimately benefit millions of Californians suffering from diabetes, heart disease, neurodegenerative diseases, etc. Breakthroughs in stem cell research in California will also generate new industries, reducing joblessness and bolstering the California economy.

Progress Report: 
  • Our plan is to find ways to facilitate transplants of stem cell-derived cells to genetically different recipients. We propose to inactivate the rejection capability of natural killer cells, a white blood cell type that can reject transplanted cells. To explore this we started with a mouse model. Previously we generated evidence that there are one or more cell types in normal mice can inactivate the rejection capacity of natural killer cells. Our first aim is to identify that cell type to see it can be injected into mice to inactivate the natural killer cells. In the last year we have generated evidence that the relevant cell type is a non-blood cell type. We will now test various non-blood cell types to see which ones have this capability. The hope is that once the cell type has been identified, it could be generated from stem cells and injected into patients to facilitate transplants of other cell types derived from the same stem cells.
  • Our plan is to find ways to facilitate transplants of stem cell-derived cells to genetically different recipients. We propose to inactivate the rejection capability of natural killer cells, a white blood cell type that can reject transplanted cells. To explore this we started with a mouse model. Previously we generated evidence that there are one or more cell types in normal mice can inactivate the rejection capacity of natural killer cells. Our first aim is to identify that cell type to see it can be injected into mice to inactivate the natural killer cells. In the last year we discovered that the relevant cells include both blood cell types and non blood cell types. We showed however, that tolerance induced by non-blood cell types induces a more stable type of tolerance than that induced by blood cell types. We went on to develop a system in live mice to test subtypes of cells that can induce tolerance. Using this system, we could show that a heterogeneous mixture of blood cell types could induce tolerance. The system is suitable for testing specific blood cell, or non blood cell, types for their capacity to induce tolerance. We will undertake those studies in the coming months. The hope is that once the cell type has been identified, it could be generated from stem cells and injected into patients to facilitate transplants of other cell types derived from the same stem cells.
  • Stem cell therapy involves transfer of stem cells to patients. Transferring stem cells from a donor to a patient holds particular promise, because the stem cells may be reliably modified to rectify a specific defect and restore a particular function. This approach is limited by the patient’s immune response, which may reject the foreign transplant. Immune suppressive drugs can be used to prevent rejection of the stem cell, but these drugs leave patients sensitive to infections. We aim to find new, less debilitating methods to facilitate transplantation of foreign stem cell derived tissues. One approach is to establish a state of immune tolerance in the patient, by transplanting blood cells to generate blood cell mixing, called chimerism— that the patient tolerates. Once that is successful, stem cells of other tissues will also be tolerated, as long as they are from the same donor as the donor blood cells. Our efforts have focused on enabling patients to accept foreign blood cells—the first step in this approach. Natural killer cells are immune cells that are known to reject foreign blood cells, when the donor cells are mismatched at genes that control tissue rejection. We have shown that natural killer cells can be rapidly converted to a tolerant state when exposed to specific foreign cells from a donor. Subsequently, they will ignore transplants from the same donor. These findings suggested we could develop methods to readily prevent rejection of foreign blood cells by natural killer cells, but we also learned that this tolerance is fragile: when infections occurred, the tolerance could be reversed and the donor cells rejected. If this occurred after stem cell therapy, the donor stem cells would be rejected, abrogating the benefit of stem cell therapy. However, we also learned that this outcome did not occur in all circumstances. We learned that the fragile state of tolerance occurred when natural killer cells were exposed to foreign blood cells, but a distinct or deeper state of tolerance occurred when NK cells were exposed to other types of foreign cells, not of the blood cell lineages. In that case, tolerance was much less fragile and was sustained even when infections occurred. Our research is geared to identifying the key cell types that induce a deeper and less fragile form of tolerance of natural killer cells, in order to improve the effectiveness of therapeutic stem cell therapy.

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