Heart Disease

Coding Dimension ID: 
295
Coding Dimension path name: 
Heart Disease
Funding Type: 
New Faculty Physician Scientist
Grant Number: 
RN3-06455
Investigator: 
Name: 
Type: 
PI
ICOC Funds Committed: 
$3 004 315
Disease Focus: 
Heart Disease
Stem Cell Use: 
iPS Cell
oldStatus: 
Active
Public Abstract: 

Despite therapeutic advances, cardiovascular disease remains a leading cause of mortality and morbidity in California. Regenerative therapies that restore normal function after a heart attack would have an enormous societal and financial impact. Although very promising, regenerative cardiac cell therapy faces a number of challenges and technological hurdles. Human induced pluripotent stem cells (hiPSC) allow the potential to deliver patient specific, well-defined cardiac progenitor cells (CPC) for regenerative clinical therapies. We propose to translate recent advances in our lab into the development of a novel, well-defined hiPSC-derived CPC therapy. All protocols will be based on clinical-grade, FDA-approvable, animal product-free methods to facilitate preclinical testing in a large animal model.
This application will attempt to translate these findings by:
-Developing techniques and protocols utilizing human induced pluripotent stem cell-derived cardiac progenitor cells at yields adequate to conduct preclinical large animal studies.
-Validation of therapeutic activity will be in small and large animal models of ischemic heart disease by demonstrating effectiveness of hiPSC-derived CPCs in regenerating damaged myocardium post myocardial infarction in small and large animal models.
This developmental candidate and techniques described here, if shown to be a feasible alternative to current approaches, would offer a novel approach to the treatment of ischemic heart disease.

Statement of Benefit to California: 

Cardiovascular disease remains the leading cause of morbidity and mortality in California and the US costing the healthcare system greater than 300 billion dollars a year. Although current therapies slow progression of heart disease, there are few options to reverse or repair the damaged heart. The limited ability of the heart to regenerate following a heart attack results in loss of function and heart failure. Human clinical trials testing the efficacy of adult stem cell therapy to restore mechanical function after a heart attack, although promising, have had variable results with modest improvements.
The discovery of human induced pluripotent stem cells offers a potentially unlimited renewable source for patient specific cardiac progenitor cells. However, practical application of pluripotent stem cells or their derivatives face a number of challenges and technological hurdles. We have demonstrated that cardiac progenitor cells, which are capable of differentiating into all cardiovascular cell types, are present during normal fetal development and can be isolated from human induced pluripotent stem cells. We propose to translate these findings into a large animal pre-clinical model and eventually to human clinical trials. This could lead to new therapies that would restore heart function after a heart attack preventing heart failure and death. This will have tremendous societal and financial benefits to patients in California and the US in treating heart failure.

Progress Report: 
  • Cardiovascular disease remains to be a major cause of morbidity and mortality in California and the United States. Despite the best medical therapies, none address the issue of irreversible myocardial tissue loss after a heart attack and thus there has been a great interest to develop approaches to induce regeneration. Our lab has focused on harvesting the full potential of patient specific induced pluripotent stem cells (iPSCs) to use to attempt to regenerate the damaged tissue. We believe that these iPSCs can be potentially used in the future to generate sufficient number of cells to be implanted in the damaged heart to regenerate the lost tissue post heart attack. Our lab has studied how these cardiac progenitors evolve in the developing heart and applied our finding to iPSCs to recapitulate the cardiac progenitors to ultimately use in clinical therapies. We have successfully derived these cardiac progenitors from patient derived iPSCs in a clinical grade fashion to ensure that we can apply same protocols in the future to clinical use if we are successful in demonstrating the efficacy of this therapy in our translational large animal studies that we will be conducting.
  • Cardiovascular disease remains to be a major cause of morbidity and mortality in California and the United States. Despite the best medical therapies, none address the issue of irreversible myocardial tissue loss after a heart attack and thus there has been a great interest to develop approaches to induce regeneration. Our lab has focused on harvesting the full potential of patient specific induced pluripotent stem cells (iPSCs) to use to attempt to regenerate the damaged tissue. We believe that these iPSCs can be potentially used in the future to generate sufficient number of cells to be implanted in the damaged heart to regenerate the lost tissue post heart attack. Our lab has studied how these cardiac progenitors evolve in the developing heart and applied our finding to iPSCs to recapitulate the cardiac progenitors to ultimately use in clinical therapies. We have successfully derived these cardiac progenitors from patient derived iPSCs in a clinical grade fashion to ensure that we can apply same protocols in the future to clinical use if we are successful in demonstrating the efficacy of this therapy in our translational large animal studies that we will be conducting. We currently are testing their in vivo regeneration potential in small animal studies to assess their safety and efficacy in regenerating the damaged heart.
Funding Type: 
Early Translational IV
Grant Number: 
TR4-06857
Investigator: 
ICOC Funds Committed: 
$6 361 618
Disease Focus: 
Heart Disease
Stem Cell Use: 
iPS Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Active
Public Abstract: 

This project uses patient hiPSC-derived cardiomyocytes to develop a safe and effective drug to treat a serious heart health condition. This research and product development will provide a novel method for a human genetic heart disorder characterized by long delay (long Q-T interval) between heart beats caused by mutations in the Na+ channel α subunit. Certain patients are genetically predisposed to a potentially fatal arrhythmogenic response to existing drugs to treat LQT3 since the drugs have off-target effects on other important ion channels in cardiomyocytes. We will use patient-derived hiPSC-cardiomyocytes to develop a safer drug (development candidate, DC) that will retain efficacy against the "leaky" Na+-channel yet minimize off-target effects in particular against the K+ hERG channel that can be responsible for the existing drug’s pro-arrhythmic effect. Since this problem is thought to occur severely in patients with the common KCHN2 variant, K897T (~33% of the white population), removing the off-target liability addresses a serious unmet clinical need. Futher, since we propose to modify an existing drug (i.e., do drug rescue), the path from patient-specific hiPSCs to clinic might be easier than for a completely new chemical entity. Lastly, an appealing aspect is that the hiPSCs were derived from a child to test his therapy, & we aim to produce a better drug for his treatment. Our goal is to complete development of the DC and initiate IND-enabling in vivo studies.

Statement of Benefit to California: 

In the US, an estimated 850,000 adults are hospitalized for arrhythmias each year, making arrhythmias one of the top five causes of healthcare expenditures in the US with a direct cost of more than $40 billion annually for diagnosis, treatment & rehabilitation. The State of California has approximately 12% of the US population which translates to 102,000 individuals hospitalized every year for arrhythmias. Another 30,000 Californians die of sudden arrhythmic death syndrome every year. Arrhythmias are very common in older adults and because the population of California is aging, research to address this issue is important for human health and the State economy. Most serious arrhythmias affect people older than 60. This is because older adults are more likely to have heart disease & other health problems that can lead to arrhythmias. Older adults also tend to be more sensitive to the side effects of medicines, some of which can cause arrhythmias. Some medicines used to treat arrhythmias can even cause arrhythmias as a side effect. In the US, atrial fibrillation (a common type of arrhythmia that can cause problems) affects millions of people & the number is rising. Accordingly, the same problem is present in California. Thus, successful completion of this work will not only provide citizens of California much needed advances in cardiovascular health technology & improvement in health care but an improved heart drug. This will provide high paying jobs & significant tax revenue.

Progress Report: 
  • The project objective is to design, synthesize and test a sodium-channel inhibitor analog that selectively inhibits the sodium channel and not the potassium channel in patient-derived IPSCs. The strategy is to first work out the approach with wild-type human IPSCs in advance of the patient-derived cells. The status is that the milestones for Year 1 have largely been accomplished. The achievements for this reporting period include nearly locking down the IPSC protocol, developing ultra high throughput kinetic analysis of human cardiomyocytes, developing an enantioselective synthesis of sodium-channel inhibitors and analogs and identifying from a pool of only 49 compounds, a promising sodium-channel inhibitor that provides insight into selective sodium channel inhibition.
Funding Type: 
Tissue Collection for Disease Modeling
Grant Number: 
IT1-06596
Investigator: 
Name: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$1 435 371
Disease Focus: 
Heart Disease
oldStatus: 
Active
Public Abstract: 

Heart failure is a very common and chronic condition defined by an inability of the heart to pump blood effectively. Over half of cases of heart failure are caused by a condition called dilated cardiomyopathy, which involves dilation of the heart cavity and weakening of the muscle. Importantly, many cases of this disease do not have a known cause and are called “idiopathic” (i.e., physicians do not know why). Over the past 2 decades, doctors and scientists started realizing the disease can cluster in families, leading them to think there is a genetic cause to the disease. This resulted in discovering multiple genes that cause this disease. Nonetheless, the majority of cases of dilated hearts that cluster in families do not have a known genetic cause. Now scientists can turn blood and skin cells into heart cells by genetically manipulating them and creating engineered stem cells called “induced pluripotent stem cells” or iPSCs. This approach enables the scientists to study what chemical or genetic changes are happening to cause the problem. Also because these cells behave similar to the cells in the heart, scientists can now test new medicines on these cells first before trying them in patients. Here we aim to collect tissue from 800 patients without a known cause for their dilated hearts (and 200 control individuals) to help accelerate our understanding of this debilitating disease and hopefully offer new and better treatments.

Statement of Benefit to California: 

Heart failure is a significant health burden in California with rising hospitalization and death rates in the state. We have a very limited understanding of the disease and so far the existing treatments only slow down the disease and the changes that happen rather than target the root cause. By studying a subgroup of the dilated cardiomyopathy patients who have no identified cause, we can work on identifying genetic causes of the disease, some of the biology happening inside the heart cell, and provide new treatments that can prevent the disease from happening or progressing. Improving the outcome of this debilitating disease and providing new treatments will go a long way to helping a large group of Californians lead healthier and longer lives. There are estimates that the US economy loses $10 billion (not counting medical costs), because heart failure patients are unable to work. Hence new knowledge and developments gained from this research can go a long way to ameliorating that cost. Finally, heart failure is the most common chronic disease patients in California are hospitalized for. This research targets over half of those admissions. If this research is able to cut the hospitalization rate even by 1%, this would translate to millions of dollars in savings to the state. Continuing to invest in innovation will make our state a hotbed for the biotechnology industry, which in turn advances the state’s economic and educational status.

Progress Report: 
  • Heart failure is a leading cause of morbidity and mortality in California and the Western world with a significant economic burden due to the disease. Over half of heart failure cases are due to dilated cardiomyopathy, a disorder of progressive ventricular dilation and decreased contractility. However, after ischemic cardiomyopathy, the majority of familial cases of dilated cardiomyopathy are unknown or "idiopathic", suggesting a polygenic etiology with a complex genetic-environmental interaction. Traditionally, studying this disorder has been impaired by inability to access cardiac tissue and the limitation of mouse models in recapitulating the disorder. Thus, we propose using human induced pluripotent stem cells (iPSCs) to study idiopathic familial dilated cardiomyopathy (IFDC). We propose collecting tissue from individuals identified with the disorder In summary, this proposal represents a unique
  • opportunity to improve our understanding of idiopathic familial dilated cardiomyopathy (which remains largely a mystery), identifying novel genetic causes (rendering many of these patients no longer “idiopathic), and proposing new therapeutic targets.
Funding Type: 
Tools and Technologies II
Grant Number: 
RT2-02060
Investigator: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$1 869 487
Disease Focus: 
Blood Disorders
Heart Disease
Liver Disease
Stem Cell Use: 
Embryonic Stem Cell
iPS Cell
oldStatus: 
Active
Public Abstract: 

Purity is as important for cell-based therapies as it is for treatments based on small-molecule drugs or biologics. Pluripotent stem cells possess two properties: they are capable of self regeneration and they can differentiate to all different tissue types (i.e. muscle, brain, heart, etc.). Despite the promise of pluripotent stem cells as a tool for regenerative medicine, these cells cannot be directly transplanted into patients. In their undifferentiated state they harbor the potential to develop into tumors. Thus, tissue-specific stem cells as they exist in the body or as derived from pluripotent cells are the true targets of stem cell-based therapeutic research, and the cell types most likely to be used clinically. Existing protocols for the generation of these target cells involve large scale differentiation cultures of pluripotent cells that often produce a mixture of different cell types, only a small fraction of which may possess therapeutic potential. Furthermore, there remains the real danger that a small number of these cells remains undifferentiated and retains tumor-forming potential. The ideal pluripotent stem cell-based therapeutic would be a pure population of tissue specific stem cells, devoid of impurities such as undifferentiated or aberrantly-differentiated cells.
We propose to develop antibody-based tools and protocols to purify therapeutic stem cells from heterogeneous cultures. We offer two general strategies to achieve this goal. The first is to develop antibodies and protocols to identify undifferentiated tumor-forming cells and remove them from cultures. The second strategy is to develop antibodies that can identify and isolate heart stem cells, and blood-forming stem cells capable of engraftment from cultures of pluripotent stem cells. The biological underpinning of our approach is that each cell type can be identified by a signature surface marker expression profile.
Antibodies that are specific to cell surface markers can be used to identify and isolate stem cells using flow cytometry. We can detect and isolate rare tissue stem cells by using combinations of antibodies that correspond to the surface marker signature for the given tissue stem cell. We can then functionally characterize the potential of these cells for use in regenerative medicine.
Our proposal aims to speed the clinical application of therapies derived from pluripotent cell products by reducing the risk of transplanting the wrong cell type - whether it is a tumor-causing residual pluripotent cell or a cell that is not native to the site of transplant - into patients. Antibodies, which exhibit exquisitely high sensitivity and specificity to target cellular populations, are the cornerstone of our proposal. The antibodies (and other technologies and reagents) identified and generated as a result of our experiments will greatly increase the safety of pluripotent stem cell-derived cellular therapies.

Statement of Benefit to California: 

Starting with human embryonic stem cells (hESC), which are capable of generating all cell types in the body, we aim to identify and isolate two tissue-specific stem cells – those that can make the heart and the blood – and remove cells that could cause tumors. Heart disease remains the leading cause of mortality and morbidity in the West. In California, 70,000 people die annually from cardiovascular diseases, and the cost exceeded $48 billion in 2006. Despite major advancement in treatments for patients with heart failure, which is mainly due to cellular loss upon myocardial injury, the mortality rate remains high. Similarly, diseases of the blood-forming system, e.g. leukemias, remain a major health problem in our state.
hESC and induced pluripotent stem cells (collectively, pluripotent stem cells, or PSC) could provide an attractive therapeutic option to treat patients with damaged or defective organs. PCS can differentiate into, and may represent a major source of regenerating, cells for these organs. However, the major issues that delay the clinical translation of PSC derivatives include lack of purification technologies for heart- or blood-specific stem cells from PSC cultures and persistence of pluripotent cells that develop into teratomas. We propose to develop reagents that can prospectively identify and isolate heart and blood stem cells, and to test their functional benefit upon engraftment in mice. We will develop reagents to identify and remove residual PSC, which give rise to teratomas. These reagents will enable us to purify patient-specific stem cells, which lack cancer-initiating potential, to replenish defective or damaged tissue.
The reagents generated in these studies can be patented forming an intellectual property portfolio shared by the state and the institutions where the research is carried out. 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. Only California businesses are likely to be able to license these reagents and to develop them into diagnostic and therapeutic entities; such businesses are at the heart of the CIRM strategy to enhance the California economy. Most importantly, this research will set the platform for future stem cell-based therapies. Because tissue stem cells are capable of lifelong self-renewal, stem cell therapies have the potential to be a single, curative treatment. Such therapies will address chronic diseases with no cure that cause considerable disability, leading to substantial medical expense. We expect that California hospitals and health care entities will be first in line for trials and therapies. Thus, California will benefit economically and it will help advance novel medical care.

Progress Report: 
  • Our program is focused on improving methods that can be used to purify stem cells so that they can be used safely and effectively for therapy. A significant limitation in translating laboratory discoveries into clinical practice remains our inability to separate specific stem cells that generate one type of desired tissue from a mixture of ‘pluripotent’ stem cells, which generate various types of tissue. An ideal transplant would then consist of only tissue-specific stem cells that retain a robust regenerative potential. Pluripotent cells, on the other hand, pose the risk, when transplanted, of generating normal tissue in the wrong location, abnormal tissue, or cancer. Thus, we have concentrated our efforts to devise strategies to either make pluripotent cells develop into desired tissue-specific stem cells or to separate these desired cells from a mixture of many types of cells.
  • Our approach to separating tissue-specific stem cells from mixed cultures is based on the theory that every type of cell has a very specific set of molecules on its surface that can act as a signature. Once this signature is known, antibodies (molecules that specifically bind to these surface markers) can be used to tag all the cells of a desired type and remove them from a mixed population. To improve stem cell therapy, our aim is to identify the signature markers on: (1) the stem cells that are pluripotent or especially likely to generate tumors; and (2) the tissue-specific stem cells. By then developing antibodies to the pluripotent or tumor-causing cells, we can exclude them from a group of cells to be transplanted. By developing antibodies to the tissue-specific stem cells, we can remove them from a mixture to select them for transplantation. For the second approach, we are particularly interested in targeting stem cells that develop into heart (cardiac) tissue and cells that develop into mature blood cells. As we develop ways to isolate the desired cells, we test them by transplanting them into animals and observing how they grow.
  • Thus, the first goal of our program is to develop tools to isolate pluripotent stem cells, especially those that can generate tumors in transplant recipients. To this end, we tested an antibody aimed at a pluripotent cell marker (stage-specific embryonic antigen-5 [SSEA-5]) that we previously identified. We transplanted into animals a population of stem cells that either had the SSEA-5-expressing cells removed or did not have them removed. The animals that received the transplants lacking the SSEA-5-expressing cells developed smaller and fewer teratomas (tumors consisting of an abnormal mixture of many tissues). Approaching the problem from another angle, we analyzed teratomas in animals that had received stem cell transplants. We found SSEA-5 on a small group of cells we believe to be responsible for generating the entire tumor.
  • The second goal of the program is to develop methods to selectively culture cardiac stem cells or isolate them from mixed cultures. Thus, in the last year we tested procedures for culturing pluripotent stem cells under conditions that cause them to develop into cardiac stem cells. We also tested a combination of four markers that we hypothesized would tag cardiac stem cells for separation. When these cells were grown under the proper conditions, they began to ‘beat’ and had electrical activity similar to that seen in normal heart cells. When we transplanted the cells with the four markers into mice with normal or damaged hearts, they seemed to develop into mature heart cells. However, these (human) cells did not integrate with the native (mouse) heart cells, perhaps because of the species difference. So we varied the approach and transplanted the human heart stem cells into human heart tissue that had been previously implanted in mice. In this case, we found some evidence that the transplanted cells differentiated into mature heart cells and integrated with the surrounding human cells.
  • The third goal of our project is to culture stem cells that give rise only to blood cells and test them for transplantation. In the past year, we developed a new procedure for treating cultures of pluripotent stem cells so that they differentiate into specific stem cells that generate blood cells and blood vessels. We are now working to refine our understanding and methods so that we end up with a culture of differentiated stem cells that generates only blood cells and not vessels.
  • In summary, we have discovered markers and tested combinations of antibodies for these markers that may select unwanted cells for removal or wanted cells for inclusion in stem cell transplants. We have also begun to develop techniques for taking a group of stem cells that can generate many tissue types, and growing them under conditions that cause them to develop into tissue-specific stem cells that can be used safely for transplantation.
  • Our program is focused on improving methods to purify blood-forming and heart-forming stem cells so that they can be used safely and effectively for therapy. Current methods to identify and isolate blood-forming stem cells from bone marrow and blood are efficient. In addition, we found that if blood-forming stem cells are transplanted, they create in the recipient an immune system that will tolerate (i.e., not reject) organs, tissues, or other types of tissue stem cells (e.g. skin, brain, or heart) from the same donor. Many living or recently deceased donors often cannot contribute these stem cells, so we need, in the future, a single biological source of each of the different types of stem cells (e.g., blood and heart) to change the entire field of regenerative medicine. The ultimate reason to fund embryonic stem cell and other pluripotent stem cell research is to create safe banks of predefined pluripotent cells. Protocols to differentiate these cells to the appropriate blood-forming stem cells could then be used to induce tolerance of other tissue stem cells from the same embryonic stem cell line. However, existing protocols to differentiation stem cells often lead to pluripotent cells (cells that generate multiple types of tissue), which pose a risk of generating normal tissue in the wrong location, abnormal tissue, or cancers called teratomas. To address these problems, we have concentrated our efforts to devise strategies to (a) make pluripotent cells develop into desired tissue-specific stem cells, and (b) to separate these desired cells from all other cells, including teratoma-causing cells. In the first funding period of this grant, we succeeded in raising antibodies that identify and eliminate teratoma-causing cells.
  • In the past year, we identified surface markers of cells that can only give rise to heart tissue. First we studied the genes that were activated in these cells, further confirming that they would likely give rise to heart tissue. Using antibodies against these surface markers, we purified heart stem cells to a higher concentration than has been achieved by other purification methods. We showed that these heart stem cells can be transplanted such that they integrate into the human heart, but not mouse heart, and participate in strong and correctly timed beating.
  • In the embryo, a group of early stem cells in the developing heart give rise to (a) heart cells; (b) cells lining the inner walls of blood vessels; and (c) muscle cells surrounding blood vessels. We identified cell surface markers that could be used to separate each of these subsets from each other and from their common stem cell parents. Finally, we determined that a specific chemical in the body, fibroblast growth factor, increased the growth of a group of pluripotent stem cells that give rise to more specific stem cells that produce either blood cells or the lining of blood vessels. This chemical also prevented blood-forming stem cells from developing into specific blood cells.
  • In the very early embryo, pluripotent cells separate into three distinct categories called ‘germ layers’: the endoderm, mesoderm, and ectoderm. Each of these germ layers later gives rise to certain organs. Our studies of the precursors of mesoderm (the layer that generates the heart, blood vessels, blood, etc.) led us by exclusion to develop techniques to direct ES cell differentiation towards endoderm (the layer that gives rise to liver, pancreas, intestinal lining, etc.). A graduate student before performed most of this work before he joined in our effort to find ways to make functional blood forming stem cells from ES cells. He had identified a group of proteins that we could use to sequentially direct embryonic stem cells to develop almost exclusively into endoderm, then subsets of digestive tract cells, and finally liver stem cells. These liver stem cells derived from embryonic stem cells integrated into mouse livers and showed signs of normal liver tissue function (e.g., secretion of albumin, a major protein in the blood). Using the guidelines of the protocols that generated these liver stem cells, we have now turned our attention back to our goal of generating from mesoderm the predecessors of blood-forming stem cells, and, ultimately, blood-forming stem cells.
  • In summary, we have continued to discover signals that cause pluripotent stem cells (which can generate many types of tissue) to become tissue-specific stem cells that exclusively develop into only heart, blood cells, blood vessel lining cells, cells that line certain sections of the digestive tract, or liver cells. This work has also involved determining the distinguishing molecules on the surface of various cells that allow them to be isolated and nearly purified. These results bring us closer to being able to purify a desired type of stem cell to be transplanted safely to generate only a single type of tissue.
  • The main focus of our program is to improve methods to generate pure populations of tissue-specific stem cells that form only heart tissue or blood. Such tissue-specific stem cells are necessary for developing safe and effective therapies. If injected into patients with heart damage, heart-forming stem cells might be used to regenerate healthy heart tissue. Blood-forming stem cells are capable of regenerating the blood-forming system after cancer therapy and replacing a defective blood forming-system. We showed that blood-forming stem cells from a given donor induce in the recipient permanent transplant tolerance of all organs, tissues, or other tissue stem cells from the same donor. Therefore, having a single biological source of each of the different types of stem cells (e.g., blood and heart) would revolutionize regenerative medicine.
  • Our projects involve generating tissue-specific stem cells from pluripotent stem cells (PSCs), the latter of which are stem cells that can form all tissues of the body. PSCs (which include embryonic stem cells and induced pluripotent stem cells) can turn into all types of more specialized cells in a process known as “differentiation.” Because PSCs can be grown to very large numbers, differentiating PSCs into tissue-specific stem cells could lead to banks of defined tissue stem cells for transplantation into patients—the ultimate reason to conduct PSC research.
  • However, current methods to differentiate PSCs often generate mixtures of various cell types that are unsafe for injection into patients. Therefore, generating a pure population of a desired cell type from PSC is pivotal for regenerative medicine—purity is a key concern for cell therapy as it is with medications.
  • We have invented technologies to purify desired types of cells from complex cell populations, allowing us to precisely isolate a pure population of tissue-specific stem cells from differentiating PSCs for cell therapy. For instance, in our work on heart-forming cells, we developed labels for cells that progressively give rise to heart cells. We used these labeled cells to clarify the natural, stepwise, differentiation process that leads from PSCs to heart-forming stem cells, and finally to different cells within the heart. Exploiting these technologies to isolate desired cell types, we have completed the first step of turning human PSCs into heart-forming stem cells. In the laboratory, when we transplanted these heart-forming stem cells into a human heart, they integrated with the surrounding tissue and participated in correctly timed beating. In the future we hope to deliver heart-forming stem cells into the damaged heart to regenerate healthy tissue.
  • We have also attempted to turn PSCs into blood-forming stem cells by understanding the complex process of blood formation in the early embryo. As mentioned above, if blood-forming stem cells are transplanted into patients, they create in the recipient an immune system that will tolerate (i.e., not reject) other tissues and types of tissue stem cells (e.g., for skin or heart) from the same donor. Thus, turning PSCs into blood-forming stem cells will provide the basis for all regenerative medicine, whereby the blood-forming stem cells and the needed other tissue stem cells can be generated from the same pluripotent cell line and be transplanted together.
  • In parallel studies to those above, we have turned PSCs into liver-forming stem cells. In the embryo, the liver emerges from a cell type known as endoderm, whereas the blood and heart emerge from a different cell type known as mesoderm. We learned that PSCs could only be steered to form endoderm (and subsequently, liver) by diverting them away from the path that leads to mesoderm. Through this approach, we could turn human PSCs into endoderm cells (at >99% purity) and then into liver-forming stem cells that, when injected into the mouse liver, gave rise to human liver cells. This could be of therapeutic importance for human patients with liver damage.
  • Finally, we have developed methods to deplete PSCs from mixtures of cells differentiated from PSCs, because residual PSCs in these mixtures can form tumors (known as teratomas). These methods should increase the safety of PSC-derived tissue stem cell therapy.
  • In summary, we have developed methods to turn PSCs to tissue-specific stem cells that exclusively develop into only heart, blood cells, or liver cells. This work has involved determining the distinguishing molecules on the surface of various cells that allow them to be isolated and nearly purified. These results bring us closer to being able to purify a desired type of stem cell to be transplanted safely to generate only a single type of tissue.
Funding Type: 
Early Translational III
Grant Number: 
TR3-05593
Investigator: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$6 319 110
Disease Focus: 
Heart Disease
Stem Cell Use: 
Directly Reprogrammed Cell
oldStatus: 
Active
Public Abstract: 

Heart disease is a leading cause of mortality. The underlying pathology is typically loss of heart muscle cells that leads to heart failure. Because heart muscle has little or no regenerative capacity after birth, current therapeutic approaches are limited for the over 5 million Americans who suffer from heart failure. Our recent findings regarding direct reprogramming of a type of structural cell of the heart, called fibroblasts, into cardiac muscle-like cells using just three genes offers a novel approach to achieving cardiac regeneration. 50% of cells in the human heart are cardiac fibroblasts, providing a potential source of new heart muscle cells for regenerative therapy. We simulated a heart attack in mice by blocking the coronary artery, and have been able to reprogram existing mouse cardiac fibroblasts in to new muscle by delivering the three genes into the heart. We found a significant reduction in scar size and an improvement in cardiac function that persists after injury. The reprogramming of cells in the intact organ was more complete than in cells in a dish. We now propose to develop the optimal gene therapy approach to introduce cardiac reprogramming genes into the heart, to establish the optimal delivery approach to administer virus encoding cardiac reprogramming factors that results in improvement in cardiac function in a preclinical model of cardiac injury, and to establish the safety profile of in vivo cardiac reprogramming in a preclinical model.

Statement of Benefit to California: 

This research will benefit the state of California and its citizens by helping develop a new therapeutic approach to cardiac regeneration. Heart disease is a leading cause of death in adults and children in California, but there is no current treatment that can promote cardiac regeneration. This proposal will lay the groundwork for a clinical trial that could result in generation of new heart muscle cells from within the heart. If successful, there is potential economic benefit in terms of productive lives saved and in the commercialization of this technology.

Progress Report: 
  • Heart disease is a leading cause of mortality. The underlying pathology is typically loss of heart muscle cells that leads to heart failure. Because heart muscle has little or no regenerative capacity after birth, current therapeutic approaches are limited for the over 5 million Americans who suffer from heart failure. Our recent findings regarding direct reprogramming of a type of structural cell of the heart, called fibroblasts, into cardiac muscle-like cells using just three genes offers a novel approach to achieving cardiac regeneration. 50% of cells in the human heart are cardiac fibroblasts, providing a potential source of new heart muscle cells for regenerative therapy. We simulated a heart attack in mice by blocking the coronary artery, and have been able to reprogram existing mouse cardiac fibroblasts into new muscle by delivering the three genes into the heart. We found a significant reduction in scar size and an improvement in cardiac function that persists after injury. The reprogramming of cells in the intact organ was more complete than in cells in a dish. We now identified a combination of factors that reprogram human and pig cardiac fibroblasts and are optimizing a gene therapy approach to introduce cardiac reprogramming genes into the heart of pigs. In a pig model of cardiac injury, these factors were able to convert non-muscle cells into new muscle in the area of injury. We also found a viral vector that can preferentially infect the fibroblasts compare to the muscle cells. We are now in a position to test for functional improvement in pigs.
  • Heart disease is a leading cause of mortality. The underlying pathology is typically loss of heart muscle cells that leads to heart failure. Because heart muscle has little or no regenerative capacity after birth, current therapeutic approaches are limited for the over 5 million Americans who suffer from heart failure. Our recent findings regarding direct reprogramming of a type of structural cell of the heart, called fibroblasts, into cardiac muscle-like cells using just three genes offers a novel approach to achieving cardiac regeneration. We simulated a heart attack in mice by blocking the coronary artery, and have regenerated damaged hearts by converting existing mouse cardiac fibroblasts into new muscle by delivering the three genes into the heart. We have found that a combination of the three genes used in mice plus two additional factors were sufficient to identified to reprogram human and pig cardiac fibroblasts and are optimizing a gene therapy approach to introduce cardiac reprogramming genes into the heart of pigs. In a pig model of cardiac injury, we identified the optimal combination of factors that was able to convert non-muscle cells into new muscle in the area of injury. We have completed a pilot study of these five factors for functional improvement using MRI to measure cardiac output 3 days after injury and 2 months after treatment with the reprogramming factors. We also found a viral vector that can preferentially infect the fibroblasts compare to the muscle cells and have confirmed this activity. We are now testing for functional improvement in pigs using various viral vectors.
Funding Type: 
Research Leadership
Grant Number: 
LA1-08015
Investigator: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$6 368 285
Disease Focus: 
Heart Disease
Neurological Disorders
Pediatrics
Stem Cell Use: 
Embryonic Stem Cell
iPS Cell
Directly Reprogrammed Cell
Public Abstract: 

Tissues derived from stem cells can serve multiple purposes to enhance biomedical therapies. Human tissues engineered from stem cells hold tremendous potential to serve as better substrates for the discovery and development of new drugs, accurately model development or disease progression, and one day ultimately be used directly to repair, restore and replace traumatically injured and chronically degenerative organs. However, realizing the full potential of stem cells for regenerative medicine applications will require the ability to produce constructs that not only resemble the structure of real tissues, but also recapitulate appropriate physiological functions. In addition, engineered tissues should behave similarly regardless of the varying source of cells, thus requiring robust, reproducible and scalable methods of biofabrication that can be achieved using a holistic systems engineering approach. The primary objective of this research proposal is to create models of cardiac and neural human tissues from stem cells that can be used for various purposes to improve the quality of human health.

Statement of Benefit to California: 

California has become internationally renowned as home to the world's most cutting-edge stem cell biology and a global leader of clinical translation and commercialization activities for stem cell technologies and therapies. California has become the focus of worldwide attention due in large part to the significant investment made by the citizens of the state to prioritize innovative stem cell research as a critical step in advancing future biomedical therapies that can significantly improve the quality of life for countless numbers of people suffering from traumatic injuries, congenital disorders and chronic degenerative diseases. At this stage, additional investment in integration of novel tissue engineering principles with fundamental stem cell research will enable the development of novel human tissue constructs that can be used to further the translational use of stem cell-derived tissues for regenerative medicine applications. This proposal would enable the recruitment of a leading biomedical engineer with significant tissue engineering experience to collaborate with leading cardiovascular and neural investigators. The expected result will be development of new approaches to engineer transplantable tissues from pluripotent stem cell sources leading to new regenerative therapies as well as an enhanced understanding of mechanisms regulating human tissue development.

Funding Type: 
Tools and Technologies III
Grant Number: 
RT3-07899
Investigator: 
Type: 
PI
ICOC Funds Committed: 
$1 368 517
Disease Focus: 
Heart Disease
Stem Cell Use: 
Embryonic Stem Cell
Cell Line Generation: 
Embryonic Stem Cell
Public Abstract: 

Heart, stroke and other cardiovascular diseases are responsible for ~17 million deaths per year globally and this number is predicted to reach 23.3 million by 2030. Cardiovascular diseases impose a staggering annual cost of $300 billion on the U.S. health care system. Heart transplantation is the ultimate solution to end-stage heart failure. However, a major limitation in treating cardiac injury is the limited availability of donors; as a result, only a small fraction of patients will benefit from heart transplantation. Tissue engineering holds a great promise to create functional tissue constructs that can reestablish the structure and function of injured tissue with exciting success stories. However, many challenges regarding their development still remain. It is the goal of this project to develop a novel 3D bioprinting technology to fabricate cardiac tissues made from cell-laden hydrogels with engineered microvasculature. By integrating the advanced 3D bioprinting with stem cell technology, functional cardiac tissues will be created with biomimetic 3D microarchitecture and functional vasculature. This novel 3D-printed cardiac tissue will heal the damaged heart and improve its function to pave the way for a superior treatment option for the millions of cardiac patients in the U.S.

Statement of Benefit to California: 

Heart disease and other cardiovascular diseases are the #1 killer in California and remain a leading cause of disability and death. A major limitation in treating cardiac injury is the failure of current therapies to induce myocardium regeneration. Due to the limited availability of donors, only a fraction of individuals who could benefit from heart transplantations actually receive them. One possible avenue for remedying this situation is to artificially engineer cardiac tissues. Tissue engineering techniques have been successfully applied to engineer many types of tissue; however, many challenges regarding their development still remain. This proposal aims to make an advance in tissue engineering by developing a novel 3D bioprinting technology to fabricate tissues made from cell-laden hydrogels with engineered microvasculature. The completion of this work will be a paradigm shift and a landmark achievement in efforts towards clinical treatments of vascularized cardiac tissue using stem cells. This advanced technology can also have a significant economical impact as heart diseases impose a staggering annual cost of $300 billion on the U.S. health care system. In addition, the development of the 3D bioprinting technology and advanced biomaterials will keep California and the U.S. as a whole in the leading position in this emerging field.

Funding Type: 
Tools and Technologies III
Grant Number: 
RT3-07838
Investigator: 
Institution: 
Type: 
PI
Institution: 
Type: 
Co-PI
ICOC Funds Committed: 
$899 728
Disease Focus: 
Heart Disease
Stem Cell Use: 
Embryonic Stem Cell
Public Abstract: 

As ongoing CIRM-funded development of regenerative medicine (RM) progresses, the demand for increasing numbers of pluripotent stem cells and their differentiated derivatives has also increased. We have established a scalable suspension culture system for the production of large quantities of hESC for banking and to seed production of a number of regenerative medicine cell types, notably retinal pigmented epithelia, neural stem cells, dopaminergic neurons and cardiomyocytes, that support a number of CIRM and NIH-funded groups. In addition, we have adapted this system for the suspension production of several hESC derivative cell types, notably cardiomyocytes. While our system has provided unprecedented production capability for a number of cell products in pre-clinical and imminent clinical studies, it has proven impractical to scale up to the level that will be required for clinical trials for some hESC cell products, notably cardiomyocytes, due to high expected human doses. This project will resolve this scale-up challenge by adapting our suspension cell culture system, that is limited to 1-3L spinner culture flasks, to a more readily scalable and controllable suspension bioreactor system that utilizes “bags” capable of volumes up to 500L. Achieving this objective will remove a key barrier to progressing RM for cardiac applications as well as open the door to large clinical trials and commercialization of other regenerative medicine cell products in the years to come.

Statement of Benefit to California: 

We have developed GMP-compliant suspension cell culture processes for scalable production of hPSC and derivatives. These processes have been invaluable in our support of CIRM- and NIH-funded regenerative medicine projects, including those with RPE, NSC, DA neurons and cardiomyocytes (CM), as well as for production of GMP banks of hPSC for various projects. Our GMP-compliant suspension culture CM production process has made pre-clinical animal studies and small early clinical trials practical. However, while our current CM system is readily transferred to other groups and is meeting current production requirements, the scale requirements for anticipated high dose clinical trials is beyond the practical limitation of our spinner flask-based system. hPSC and CM are sensitive to changes in shear encountered at every scale-up step and re-optimizing conditions at each step is prohibitively expensive. Our experience using bag-based bioreactors for non-hESC products suggests that scale-up in bags will be more controllable and predictable than spinners or stir-tanks reactors. It is also a readily transferred technology. We propose to adapt our suspension hPSC and CM processes to a bag system, optimize conditions at a small scale, then demonstrate scalability at a moderate scale. Success in this project will remove a key barrier to developing many regenerative medicine products, and in particular those where high human doses are anticipated, such as CM.

Funding Type: 
Basic Biology IV
Grant Number: 
RB4-06215
Investigator: 
Type: 
PI
ICOC Funds Committed: 
$1 367 604
Disease Focus: 
Heart Disease
Stem Cell Use: 
Adult Stem Cell
oldStatus: 
Active
Public Abstract: 

In the process of a heart attack, clots form suddenly on top of cholesterol-laden plaques, blocking blood flow to heart muscle. As a result, living heart tissue dies and is replaced by scar. The larger the scar, the higher the chance of premature death and disability following the heart attack. While conventional treatments aim to limit the initial injury (by promptly opening the clogged artery) and to prevent further damage (using various drugs), regenerative therapy for heart attacks seeks to regrow healthy heart muscle and to dissolve scar. To date, cell therapy with CDCs is the only intervention which has been shown to be clinically effective in regenerating the injured human heart. However, the cellular origin of the newly-formed heart muscle and the mechanisms underlying its generation remain unknown. The present grant seeks to understand those basic mechanisms in detail, relying upon state-of-the-art scientific methods and preclinical disease models. Our work to date suggests that much of the benefit is due to an indirect effect of transplanted CDCs to stimulate the proliferation of surrounding host heart cells. This represents a major, previously-unrecognized mechanism of cardiac regeneration in response to cell therapy. The proposed project will open up novel mechanistic insights which will hopefully enable us to boost the efficacy of stem cell-based treatments by bolstering the regeneration of injured heart muscle.

Statement of Benefit to California: 

Coronary artery disease is the predominant cause of premature death and disability in California. Clots form suddenly on top of cholesterol-laden plaques in the wall of a coronary artery, blocking blood flow to the heart muscle. This leads to a “heart attack”, in which living heart muscle dies and is replaced by scar. The larger the scar, the greater the chance of death and disability following the heart attack. While conventional treatments aim to limit the initial injury (by promptly opening the clogged artery) and to prevent further injury (using various drugs), regenerative therapy for heart attacks seeks to regrow healthy heart muscle and to dissolve scar. To date, cell therapy with CDCs is the only intervention that has been shown to be clinically effective in regenerating the injured human heart. However, the cellular origin of the newly-formed heart muscle and the mechanisms underlying its generation remain unknown. The present grant seeks to understand those basic mechanisms in detail, relying upon state-of-the-art scientific methods and preclinical disease models. The resulting insights will enable more rational development of novel therapeutic approaches, to the benefit of the public health of the citizens of California. Economic benefits may also accrue from licensing of new technology.

Progress Report: 
  • Key abbreviations:
  • CDCs: cardiosphere-derived cells
  • MI: myocardial infarction
  • The present award tests the hypothesis that CDCs promote regrowth of normal mammalian heart tissue through induction of adult cardiomyocyte cell cycle re-entry and proliferation (as occurs naturally in zebrafish and neonatal mice). Such a mechanism, if established, would challenge the dogma that terminally-differentiated adult cardiomyocytes cannot re-enter the cell cycle. We have employed an inducible cardiomyocyte-specific fate-mapping approach (to specifically mark resident myocytes and their progeny), coupled with novel methods of myocyte purification and rigorous quantification. We have also developed assays that enable us to exclude potential technical confounding factors. The use of bitransgenic mice is essential for our experimental design (as it enables fate mapping of resident myocytes in a mammalian model), while the use of mouse CDCs in our in vivo experiments (as opposed to human CDCs) enables us to avoid immunosuppression and its complications. To date, mouse, rat and pig models have proven to be reliable in predicting clinical effects of CDC therapy in humans, and results with human and mouse CDCs in comparable models (e.g., SCID mice for human CDCs versus wild-type mice for mouse CDCs) have not revealed any major mechanistic divergence. Our results demonstrate that induction of cardiomyocyte proliferation represents a major, previously-unrecognized mechanism of cardiac regeneration in response to cell therapy. One full-length publication describing these findings has appeared (K. Malliaras et al., EMBO Mol Med, 2013, 5:191-209), and another paper has been submitted. The work has already begun to open up novel mechanistic insights which will enable us to improve the efficacy of stem cell-based treatments and bolster cardiomyocyte repopulation of infarcted myocardium.
  • CDCs: cardiosphere-derived cells
  • MI: myocardial infarction
  • The present award tests the hypothesis that CDCs promote regrowth of normal mammalian heart tissue through induction of adult cardiomyocyte cell cycle re-entry and proliferation (as occurs naturally in zebrafish and neonatal mice). Such a mechanism, if established, would challenge the dogma that terminally-differentiated adult cardiomyocytes cannot reenter the cell cycle. We have employed an inducible cardiomyocyte-specific fate-mapping approach (to specifically mark resident myocytes and their progeny), coupled with novel methods of myocyte purification and rigorous quantification. We have also developed assays that enable us to exclude potential technical confounding factors. The use of bitransgenic mice is essential for our experimental design (as it enables fate mapping of resident myocytes in a mammalian model), while the use of mouse CDCs in our in vivo experiments (as opposed to human CDCs) enables us to avoid immunosuppression and its complications. To date, mouse, rat, and pig models have proven to be reliable in predicting clinical effects of CDC therapy in humans, and results with human and mouse CDCs in comparable models (e.g., SCID mice for human CDCs versus wild-type mice for mouse CDCs) have not revealed any major mechanistic divergence. Our results demonstrate that induction of cardiomyocyte proliferation represents a major, previously-unrecognized mechanism of cardiac regeneration in response to cell therapy. Two full-length publications describing these findings has appeared (Malliaras, K, et al., EMBO Mol Med. 2014, 6:760-777; Malliaras K, et al., EMBO Mol Med, 2013, 5:191-209). The work has already begun to open up novel mechanistic insights which will enable us to improve the efficacy of stem cell-based treatments and bolster cardiomyocyte repopulation of infarcted myocardium.
Funding Type: 
Basic Biology IV
Grant Number: 
RB4-06035
Investigator: 
Name: 
Institution: 
Type: 
PI
ICOC Funds Committed: 
$1 708 560
Disease Focus: 
Heart Disease
Stem Cell Use: 
Directly Reprogrammed Cell
Cell Line Generation: 
iPS Cell
oldStatus: 
Active
Public Abstract: 

Recently, we devised and reported a new regenerative medicine paradigm that entails temporal/transient overexpression of induced pluripotent stem cell based reprogramming factors in skin cells, leading to the rapid generation of “activated” cells, which can then be directed by specific growth factors and small molecules to “relax” back into various defined and homogenous tissue-specific precursor cell types (including nervous cells, heart cells, blood vessel cells, and pancreas and liver progenitor cells), which can be expanded and further differentiated into mature cells entirely distinct from fibroblasts.

In this proposal, combined with small molecules that can functionally replace reprogramming transcription factors as well as substantially improve reprogramming efficiency and kinetics, we aim to further develop and mechanistically characterize chemically defined, non-integrating approaches (e.g., mRNA, miRNA, episomal plasmids and/or small molecule-based) to robustly and efficiently reprogram skin fibroblast cells into expandable heart precursor cells. Specifically, we will: determine if we can use non-integrating methods to destabilize human fibroblasts and facilitate their direct reprogramming into the heart precursor cells; characterize of heart cells generated by the direct programming methods, both in the tissue culture dish and in a mouse model of heart attack; and characterize newly identified reprogramming enhancing small molecules mechanistically.

Statement of Benefit to California: 

This study will develop and mechanistically characterize a new method of generating safe patient specific heart cells that could be useful in treating heart failure which afflicts millions of Californians and accounts for billions of dollars in healthcare spending annually. Additionally, the small molecules discovered in this study could be good candidates for future drug development as well as being broadly useful for other regenerative medicine applications. These advances could also be a platform for new personalized medicine/ cell banking businesses which could bring economic growth in addition to improving the health of Californians.

Progress Report: 
  • During the reporting period, we have made very significant progress toward the following research aims: (1) Using the Oct4-based reprogramming assay system established, we were able to screen for and identify small molecules that can replace the other three genes in the Cell-Activation and Signaling-Directed (CASD) lineage conversion paradigm for reprogramming fibroblasts into cardiac lineage. (2) Using in-depth assays, we have examined the process using lineage-tracing methods and characterized those Oct4/small molecules-reprogrammed cardiac cells in vitro. (3) Most importantly, we were able to identify a baseline condition that appears to reprogram human fibroblasts into cardiac cells using defined conditions.
  • Cardiomyocyte-like cells can be reprogrammed from somatic fibroblasts by combinations of genes in vitro1 and in vivo, providing a new avenue for cardiac regenerative therapy. However, transdifferentiating human cells to generate fully functional cardiomyocytes remains a challenge. Moreover, genetic manipulations with multiple factors used in such conventional strategies pose safety, efficacy, and technical concerns that may limit their clinical potential. In the work funded by CIRM we identified and demonstrated that functional cardiomyocytes can be rapidly and efficiently generated from fibroblasts by a combination of small molecules. These cardiomyocytes express characteristic cardiac markers, have a well-organized sarcomeric structure, contract spontaneously, and respond to pharmacological modulations. They closely resemble cardiomyocytes in their global gene expression profiles, and electrophysiological properties. This novel pharmacological reprogramming approach may have important implications in cardiac regenerative medicine.

Pages