Endogenous and exogenous mechanisms that promote myocardial remuscularization in post infarction LV remodeling

促进心肌再肌化的内源性和外源性机制

Endogenous and exogenous mechanisms that promote myocardial remuscularization in post infarction LV remodeling Summary / Abstract The molecular and cellular basis for the progressive heart failure is the result of the inability of damaged and apoptotic myocytes to be replaced. While a number of cell- and tissue-based therapies can limit this dysfunction, the proportion of cells that survive at the site of administration for more than a few weeks after transplantation is extremely low. As such, substantial remuscularization of the infarcted region has rarely been reported; and when limited remuscularization has been reported, it is frequently accompanied by potentially lethal ventricular arrhythmias of unknown mechanism. This proposal aims at remuscularization of the injured ventricle from “within” by identifying key regulators of the cell cycle and by promoting the native cardiomyocyte (CM) reenter the cell cycle, and from “outside” by transplanting bioengineered cardiac muscle patch (hCMP) with the key regulators of CM cell cycle upregulated, and with that incorporate a functional vascular network and recapitulate some of the key micro environmental cues of native heart tissue. We recently established a novel hiPSC cell line with MHC-driven overexpression of a key regulator of CM: CCND2 (hiPSC-MHC-CCND2OE), which can remuscularize injured ventricle in rodent model. The central objective of this proposal is to “turn back the clock” of myocyte cell cycle for myocardial repair. The specific Aims ( SA) are: SA1: Identifying the key regulators that promote cell-cycle activity in the hearts of early neonatal pigs after myocardial injury. We will: 1) using state-of-the-art molecular biology and imaging technologies, and the single cell/nucleus RNA sequencing (scRNAseq or snRNAseq) technology to demonstrate these key regulators/signaling pathways that control the myocyte cell cycle; and2) test remuscularization of injured ventricle by manipulating the key regulators using either targeted modRNA or AAV9 to selectively modify these regulators in adult pigs with AMI. SA2a. Engineering hCMPs of previously unattainable size and thickness that are functionally mature and primed for in-vivo vascularization. SA2b. Evaluating the effectiveness of our hCMP constructs for myocardial recovery and remuscularization in a large-animal (swine) model of myocardial injury. We will use state-of-the-art techniques of optical mapping in combination with the 3-dimensional intramural cardiac mapping to delineate potential arrhythmia mechanisms over the entire left-ventricular surface and transmurally.