Basic Biology IV
Cardiovascular disease (CVD) is the most common cause of morbidity and mortality in the US. In adults, it is most commonly caused by heart attack, which leads to reduced function of the LEFT ventricle (LV). At the same time, congenital heart disease (CHD) is the most common cause of birth defect in infants. Due to advances in infant cardiac surgery, it is now estimated >1 million adults have CHD, more than the number of children with CHD. However, many of these adult CHD patients will eventually develop dysfunction of RIGHT ventricle (RV) secondary to chronic volume overload and pulmonary hypertension (PHTN). This group of CHD patients can only be cured by heart transplantation, which is severely limited by chronic organ shortage. For our study, we will use human induced pluripotent stem (hiPS) cells reprogrammed from cells of human donors to investigate CVD and CHD. These hiPS cells will be genetically engineered to express colored flags in order to discriminate between the RV and LV progenitor cells. We will characterize the biological properties of these 2 different cell populations. We will transplant them into mouse models of MI and PHTN to demonstrate the potential of RV and LV cardiac progenitors for repair RV and LV dysfunction, respectively. Cell fate after transplantation will be carefully characterized by molecular imaging. In summary, these studies will provide valuable insights into two of the most common heart diseases affecting adults and children alike.
Statement of Benefit to California:
Cardiovascular disease (CVD) is the leading cause of morbidity and mortality in the US. In adults, it is most commonly caused by heart attacks causing reduced function of LEFT ventricle (LV). Congenital heart disease (CHD) is the most common cause of birth defect in infants. Due to advances in infant cardiac surgery, the number of pediatric and adult patients with congenital heart diseases has reached 1.8 million in the US and growing. Many of these CHD patients will eventually develop dysfunction of RIGHT ventricle (RV) secondary to chronic volume overload and pulmonary hypertension later in life. Hence there is an urgent need to generate new strategies such as stem cell therapy for these patients. Our proposal to engineer specific RV and LV cardiac cells from human pluripotent stem (hiPS) cells is highly relevant to the main goals of CIRM, one of which is to explore the therapeutic potential of hiPS cells in degenerative diseases. We further intend to deeply characterize at a genetic and epigenetic level the cells that we will transplant in animal models of RV or LV dysfunction, thus fulfilling the safety expectations of the CIRM in cell therapy. We believe the outcome of our project will have high clinical and basic science value in enabling a better understanding of cardiac developmental biology and a better cell therapy approach for both CVD and CHD, thus significantly benefiting the citizens of California.
The purpose of this proposal is to investigate the hypothesis that the ideal cells to repair right ventricle (RV) or left ventricle (LV) defects in the human heart are the corresponding RV or LV progenitor cells. First, the investigators plan to generate human induced pluripotent stem cells (hiPSCs) carrying genetic markers to distinguish RV and LV progenitors, optimize protocols for differentiation to each of those cell types, and characterize the genetic and epigenetic signatures of each cell type. Next, RV or LV progenitor cells will be transplanted into animal models of RV or LV dysfunction and the investigators propose to track cell fate and examine the therapeutic potential for each progenitor population to induce functional recovery following LV or RV dysfunction. Significance and Innovation - The primary significance is in the potential for the investigator to uncover important information regarding the embryonic development of the primary and secondary heart fields (i.e. the RV and LV). - While this proposal is based on sound rationale, the applicant, when discussing the current state of the field and significance of the proposed research, overlooks the work of others who have described generation of human RV and LV progenitor cells. Feasibility and Experimental Design - The application is under developed and lacks significant preliminary data (PD) to support the proposed research. - While aspects of the proposal are feasible, the research plan is not a well-developed and cohesive approach to investigating the hypothesis, and reviewers had doubts as to the likelihood that the overall objective could be achieved. - Overall, aim 3 is generally underdeveloped and the experimental design has flaws. - The selection of the animal models of disease is poorly justified, and it is not clear why one would expect the transplanted progenitor cells to improve function in the proposed RV dysfunction model. Further, the applicant’s choice of time points for analysis of transplanted cells is not supported (i.e. convincing data was not provided demonstrating the cells would still be present at the indicated time points). - Reviewers thought the proposal to be premature. The applicant’s use of human progenitor cells as the starting point for testing the hypothesis that RV and LV progenitor cells more effectively repair dysfunction when matched to the corresponding right or left ventricle is unnecessarily complex, and additional preliminary data using mouse progenitor cells to demonstrate proof of concept would have strengthened the proposal. Principal Investigator (PI) and Research Team - The PI is outstanding, has an excellent background in the proposed field of research, and is a strength of the proposal - Technically and intellectually, the environment is superb. - Though the investigators comprising the team are strong, the role of individual team members, the work of the collaborator, and execution of the collaboration are poorly described. Responsiveness to the RFA The application is responsive to the RFA; no relevant concerns were highlighted by reviewers for this review criterion.
- Shoukhrat Mitalipov