This project will result in a culture system to generate a therapeutic cell population from embryonic stem (ES) cells as well as a method for cell delivery to treat cardiac disease. This system will serve as a model for the translation of ES cells to fully differentiated cell types based on a biomimetic approach that closely approximates the embryonic development of cardiovascular structures in the heart. This approach overcomes the limitations in differentiation efficiency of current ES cell technology that is primarily focused on inducing differentiation via soluble signals. The unique aspect of this work is the novel use of protein-immobilized beads and insoluble factors in 3D matrix culture to encourage differentiated cell function. The Principal Investigator's (PI's) engineered systems have been designed to provide the necessary instructional cues that comprise the cellular microenvironment during development. The PI proposes to accomplish the overarching goal through a staged differentiation process that will initially drive differentiation towards a uniform mesodermal progenitor. Subsequent steps will facilitate differentiation towards a therapeutic cell population that can contribute towards cardiac repair.
Broader Impact:
The success of the research objectives would result in cell culture techniques that will serve as templates for the generation of functional, tissue-engineered constructs. The intent is to design a protocol for the generation of a readily available progenitor cell population combined with a tailored delivery system to treat patients following myocardial infarction. This would provide the scientific foundation for a timely clinical solution with none of the complications involved in tissue harvest. The educational goals are tightly linked via the ideological concept of engineering design. As a junior faculty, the PI has conceived of and implemented the entire Biomedical Engineering senior design sequence at UT Austin. The PI has a strong and continuing passion for design and its instruction and proposes that design should be integrated at all educational levels. The outreach activities described in this proposal extend from precollege through the level of the college instructor. Specific tools will be developed including teaching modules, online course resources, as well as instructional tools for use by existing pre-college outreach programs.
Heart disease remains one of the deadliest diseases in the United States, accounting for nearly 1 million deaths annually (www.theheartfoundation.org). Recently, new strategies have been developed to improve upon current treatment options, which can be invasive and high risk. Cell therapy, in which heart cells, or cardiomyocytes, are injected back into the heart to improve tissue regeneration after a heart attack, is one of such strategies. Embryonic stem cells are ideal candidates for cell therapy because they have the potential to become any cell type, including cardiomyocytes; however, the challenge is in deriving a sufficient number of cardiomyocytes to promote tissue regeneration. In our research, we developed novel regimens to generate heart cells from embryonic stem cells for the purpose of regenerating damaged tissue following heart attacks. We developed a mechanical stimulation method that can change the genes that are expressed by embryonic stem cells such that they become cardiomyocytes as opposed to any other cell type. We found that if tiny magnetic beads are coated with cell adhesion molecules, and these beads are attached to embryonic stem cells, when magnetized, they can increase the expression of cardiomyocyte-specific markers. Our research suggests that by changing the timing of mechanical stimulation, we can increase the population of cardiomyocytes, potentially developing a new method for generating cardiomyocytes from embryonic stem cells. Another important factor of successful cell therapy is cell delivery into the heart. If cells are injected directly into the damaged myocardium, they are lost soon after injection. To address this, cells are inorporated into a biomaterial, which is non-toxic and degradable, in order to physically encapsulate the cells at the site of injury. Our group has developed a fibrin-based material that can retain cells in the heart following a heart attack. In our research, we observed that this materials can also keep cardiomyocytes functional: they continue to exhibit a contracting phenotype and remain viable. This outcome, however, largely depends on how the cells are combined with the fibrin: when cells are directly incorporated into the matrix, contractile behavior stops, yet when the cells are grown on top of the matrix, they remain contractile. This research, therefore, has provided additional information on how we can generate a clinically relevant population of cardiomyocytes for the treatment of heart disease, and in addition, we can further improve functional outcomes by combining these cells with a fibrin-based material.
