Project Summary: Exosome therapy holds remarkable promise to treat acute infarction, a major cause of heart
failure that affects over 6 million people in the US. Exosomes are nanoparticles secreted by cells to facilitate
intercellular signaling through their bioactive cargos such as microRNAs (miRNAs). Compared to cell-based
therapies, exosomes have distinct advantages including low immunogenicity, absence of tumorigenic risk, and
amenable for large scale production and off-of-shelf storage. Among various exosomes used for cardiac
regenerative medicine, exosomes from human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have
received significant attention. While 2D culture has been considered as “gold standard” for exosome production,
recent studies show 3D culture promote the production of pro-reparative exosomes. To this end, we developed
nanowired human cardiac organoids, which are composed of hPSC-CMs, human primary cardiac fibroblasts,
endothelial cells, stromal cells, and electrically conductive silicon nanowires (e-SiNWs). Compared to 2D hPSC-
CM culture, organoids provide a myocardium mimetic microtissue platform, and the e-SiNWs creates a
conductive microenvironment to enhance exosome biogenesis and secretion. Compared to the unwired
organoids (without e-SiNWs), the nanowired organoids showed the significantly higher ability to improve
vascularization, preserve myocardium, attenuate pathological hypertrophy of the infarcted hearts and recover
their contractile function. To improve the reproducibility of exosomes, we developed isogenic hPSC cardiac
organoids using hPSC-CMs, -cFBs (cardiac fibroblasts), and -ECs (endothelial cells) derived from a single hPSC
line. The goal of this proposal is to determine the effects of key variables of the nanowired hPSC cardiac
organoids (i.e., size, cell composition and e-SiNW structures) on their exosome production and functionality. The
central hypothesis of the proposal is the nanowired hPSC cardiac organoids provide an electrically conductive,
biomimetic environment for hPSC-CMs, -cFBs, and -ECs to produce therapeutically potent exosomes for cardiac
repair. The proposal is innovative is that, for the first time, we will synergize electrical nanomaterials with
human cardiac organoids to enhance exosome production and functionality. Accordingly, we will pursue 2 Aims:
1): Determine the effects of cell seeding ratio, size and e-SiNW structure of the nanowired isogenic hPSC cardiac
organoids on exosome production and function, 2): Determine the therapeutic efficacy of the exosomes derived
from the optimized nanowired organoids. The proposed studies are significant in that we aim to shift the current
paradigm of exosome production to develop organ-specific therapeutic exosomes by leveraging the recent
advances in nanofabrication and engineered human cardiac organoids. These studies will provide a guiding
principle to design and develop next generation of tissue engineering constructs that can provide a source of
sustained exosome production after implantation in addition to a cell replacement therapy.