Thursday, April 10, 2025
4/10/2025
Silicon nanowire engineered human isogenic cardiac organoids for heart repair - Project Summary: Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) hold remarkable promise for treating infarcted hearts. However, the traditional strategy of intramyocardial injections of a large number of dissociated hPSC-CMs (e.g., 1E7: 1x107 hPSC-CMs/rat) has been limited by low cell survival, moderate functional improvement, arrhythmogenic risk, and poor scalability. To address this, our lab developed prevascularized, nanowired human cardiac organoids composed of hPSC-CMs, cardiac fibroblasts, endothelial cells, stromal cells, and electrically conductive silicon nanowires (e-SiNWs). Our in vivo data showed that the nanowired organoids showed superior functional recovery (~69% Fractional Shortening (FS) recovery) to previous studies that injected 10-fold greater dissociated hPSC-CMs/rat. These exciting results motivated us to further improve e-SiNWs for organoid fabrication. Both mechanism (Eq. 1 in Research Strategy) and our preliminary data showed that e-SiNW geometry (e.g., surface roughness) significantly affects their interactions with hPSC-CMs. In addition, only ~30% injected organoids engrafted into I/R injured hearts 1-week post- implantation. To address this, we used Molidustat, a selective Prolyl Hydroxylase Domain enzyme 2 (PHD2) inhibitor, to activate Hypoxia Inducible Factor (HIF) pathway to significantly improve prevascularization in the organoids and cellular survival in an ischemic condition. Lastly, we developed isogenic hPSC cardiac organoids using cardiomyocytes (hPSC-CMs), cardiac fibroblasts (-cFBs), and endothelial cells (-ECs) differentiated from a single hPSC donor to develop a patient specific cardiac regenerative therapy. The goal of this proposal is to improve the function of each isogenic organoid by optimizing nanowire roughness (Aim 1a) and increase the number of the survived organoids through PHD2 inhibition (Aim 1b) post-implantation. We will synergize the optimized e-SiNWs and PHD2 inhibitor to identify the minimal organoid dose to achieve nearly full (>90%) FS recovery in Aim 2, and the optimized organoid dose will be validated in a porcine model in Aim 3. The central hypotheses of this proposal are: 1) e-SiNW roughness significantly affects its electrical interactions with hPSC-CMs, and 2) PHD2 inhibition mediated pseudohypoxia engineering improves organoid survival post-implantation. The innovations of the proposal are that, for the first time, we will 1) reveal the effects of surface roughness of conductive nanomaterials on cardiac tissue constructs and 2) establish PHD2 inhibition as a powerful preconditioning strategy to improve hPSC-CM survival post-implantation. Accordingly, we will pursue the following 3 Aims: 1) Determine the effects of e-SiNW surface roughness and pseudohypoxia- engineering on hPSC isogenic cardiac organoids, 2) Determine the minimal dose of pseudohypoxia-engineered, nanowired isogenic organoids to treat I/R injured rat hearts, and 3) Determine therapeutic efficacy of pseudohypoxia-engineered, nanowired organoids in a porcine I/R model. The proposed studies will lay the foundation for clinical translations of the nanowired organoids as a personalized cardiac regenerative medicine.
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