Site-Specific Blockade of LPA–TRPV1 Interaction at K710 Residue Influences on Myocardial Ischemia/Reperfusion Injury in Ex Vivo Mouse Hearts

BACKGROUND: Myocardial ischemia/reperfusion (I/R) injury commonly occurs in patients undergoing cardiac or noncardiac surgeries, increasing perioperative mortality risk. Although numerous endogenous mediators released during I/R contribute to myocardial damage, their mechanisms require further elucidation. We investigated whether lysophosphatidic acid (LPA), a bioactive phospholipid, mediates myocardial I/R injury by interacting with cardiac transient receptor potential vanilloid 1 (TRPV1). METHODS: A TRPV1K710N knock-in mouse model was generated by CRISPR/Cas9, introducing a point mutation at K710, the known LPA-binding site on TRPV1. Langendorff perfused isolated hearts from TRPV1K710N and wild-type (WT) mice underwent global I/R injury with or without exogenous LPA (10 μM). Myocardial infarct size, coronary effluent LDH levels, and mitochondrial ultrastructure/function were assessed. Additionally, H9c2 cardiomyocytes were transfected with a pCMV6-entry plasmid carrying TRPV1-K710N or TRPV1-WT for mitochondrial calcium influx and cell viability assays. The V1-Cal peptide (1μM), targeting the K710 region, was applied ex vivo and in vitro to block LPA-TRPV1 interaction. RESULTS: TRPV1K710N hearts exhibited resistance to global I/R injury versus WT hearts, with reduced infarct size (28.3 ± 2.4% vs 39.9 ±2.3%, respectively, P= 0006), lower LDH levels, and attenuated mitochondrial damage. Exogenous LPA exacerbated I/R injury in WT hearts, increasing infarct size (63.7 ± 1.2% vs vehicle: 38.4 ± 2.4%; P <.0001), LDH release, and mitochondrial damage. TRPV1K710N hearts were resistant to LPA-induced injury, with no significant increase in infarct size after LPA treatment. Exogenous LPA induced pronounced swelling in mitochondria isolated from WT hearts, while mitochondria from TRPV1K710N hearts showed resistance to LPA challenge. In H9c2 cells, LPA significantly decreased viability in rTRPV1-WT cells and elevated mitochondrial calcium influx relative to rTRPV1-K710N cells. V1-Cal peptide attenuated LPA-mediated myocardial injury in WT hearts and reduced mitochondrial calcium overload in H9c2 cells. CONCLUSIONS: Blockade of the TRPV1 K710 site by K710N mutation or V1-Cal peptide mitigates LPA-mediated myocardial injury and mitochondrial damage/dysfunction in isolated mouse hearts. Targeting the cardiac LPA-TRPV1 interaction represents a promising therapeutic strategy against perioperative myocardial injury.