Optically Promoting Cardiac Maturation Using Engineered Peptides

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 stimulation or substrate-
induced tissue alignment. Methods for electrical stimulation often utilize electrode contacts for field stimulation,
bulky instrumentation for combining electrical stimuli delivery with 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 can induce tissue anisotropy and
are engineered to convert light to stimulatory cues. Our team will develop peptides functionalized with
chromophore units and cell-binding epitopes as materials that can be used for light-based stimulation of hSC-
CMs, in combination with induction of tissue alignment, towards maturation. The long-term goal of this project is
to establish light stimulation via engineered peptides as a viable method to stimulate cardiomyocytes and
promote hSC-CM maturation in an electrodeless and non-genetic manner. We hypothesize that transient
charging and other associated light-induced processes at the cardiomyocyte-biomaterial interface can influence
extracellular potential, resulting in the photostimulation 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 engineered
peptide substrates with optimal photostimulation efficiency; (2) test the cellular- and tissue-level impact of
peptide-mediated photostimulation in combination with anisotropic cues; and (3) elucidate the effect of the
proposed photostimulation method, along with anisotropy cues, on hSC-CM maturation. By establishing the
design rules for the proposed photoexcitable peptides for eliciting combinatorial cues to stimulate hSC-CMs and
ensure their capability to excite cardiac cells, this innovative approach offers a new strategy for a “wireless”
stimulation of cardiac tissues towards maturation, and can therefore significantly contribute towards addressing
the grand challenge of immaturity of stem cell-derived cardiomyocytes.

Grant Number: 5R01HL164348-03
NIH Institute/Center: NIH
Principal Investigator: Herdeline Ann Ardona