Abstract Body: Introduction/Background: Ischemia-reperfusion (IR) injury is a primary driver of post-infarction morbidity. While adiponectin is cardioprotective, its clinical use is hindered by its complex molecular structure. ALY688 is a novel, synthetic adiponectin receptor agonist designed for clinical translation.
Research Questions/Hypothesis: We hypothesized that ALY688 reduces myocardial IR injury by activating intracellular survival pathways and stimulating the release of cardioprotective extracellular vesicles (EVs).
Goals/Aims: To evaluate ALY688’s efficacy in a rat IR model and determine the role of the GTPase Rab8a in EV-mediated signaling.
Methods/Approach: Rats underwent 45-min ischemia followed by reperfusion. ALY688 was administered IV during ischemia and SC for 28 days. In vitro studies used H9c2 and human iPSC-derived cardiomyocytes (iPSC-CMs) under hypoxia-reoxygenation (HR). Proteomics characterized heart tissue and circulating EVs. Rab8a was deleted using CRISPR/Cas9.
Results/Data: ALY688 significantly reduced Troponin-I and infarct size (p<0.05), while preserving ejection fraction (EF) and fractional shortening (FS) at 28 days compared to vehicle. In vitro, ALY688 restored autophagic flux, reduced ROS, and decreased apoptosis. Proteomics revealed that ALY688 maintained Rab8a levels, which were otherwise downregulated by IR. ALY688 increased myocardial and plasma EV abundance; these EVs were enriched in glycolytic and anti-oxidative proteins. Treatment with ALY688-induced EVs protected iPSC-CMs from HR-induced death. Importantly, CRISPR-mediated Rab8a knockout abolished ALY688-induced EV biogenesis and negated the cytoprotective effects of these EVs.
Conclusion(s): ALY688 mitigates IR injury through dual cardioprotective mechanisms: direct effects on cardiomyocytes and a Rab8a-dependent EV signaling axis, making it a promising therapeutic candidate.