Optically Promoting Cardiac Maturation Using Engineered Peptides

项目总结

PROJECT SUMMARY The promise of human stem cell-derived cardiomyocytes (hSC-CMs) opens doors towards the feasibility of personalized medicine against cardiac diseases and for performing more accurate drug discovery studies. Moreover, hSC-CMs overcome the issue of species differences when using animal models for high throughput screening studies. However, one of the bottlenecks for scaling up the use of hSC-CMs is their ability to accurately reflect the native structure and function of adult human cardiomyocytes. Current efforts to address this critical challenge involve maturation protocols that use biophysical cues such as electrical and mechanical stimulation. These methods often utilize electrode contacts for field stimulation, bulky instrumentation for mechanical or sustained chemical stimulation, or genetically modifying cells to be light-responsive. Although we have seen successes through these induction and stimulation approaches, the field would benefit from a stimulation approach with minimal culture contact to reduce risk of infection during long-term cultures, as well as a light-based approach with higher spatiotemporal resolution than electrode-based stimulation. Here, we propose a new paradigm for stimulating hSC-CMs towards maturation by interfacing these cells with peptide-based substrates that are engineered to convert light to electrical cues. Our team will develop peptides engineered with chromophore units and cell-binding epitopes as materials that can be used for photoelectrical conditioning of hSC-CMs towards maturation. The long-term goal of this project is to establish photoelectrical conditioning via engineered peptides as a viable method to electrically stimulate cardiomyocytes and promote hSC-CM maturation in an electrodeless and non-genetic manner, with higher spatiotemporal resolution than field stimulation. We hypothesize that transient charging and other associated light-induced processes at the cardiomyocyte-biomaterial interface can influence extracellular potential, resulting in the photoelectrical stimulation of hSC-CMs towards maturation. Our rationale for proposing a materials-based approach for stimulating hSC-CMs stems from previous reports of conjugated polymers being used as a photoactive substrate for triggering action potentials of other excitable cells. To test our hypothesis, we propose the following specific aims: (1) establishing design parameters for peptide nanoassemblies with optimal photostimulation efficiency; (2) test the cellular- and tissue-level impact of peptide-mediated photostimulation; and (3) elucidate the effect of the proposed photoelectrical conditioning method on hSC-CM maturation. By establishing the design rules for the proposed photoexcitable peptides for stimulating hSC-CMs and ensuring their capability to locally excite cardiac cells, this innovative approach offers a new strategy for a “wireless” stimulation of cardiac tissues and can significantly contribute towards addressing the grand challenge of stem cell immaturity. 1