The effect of cell‐permeable peptides to limit TRPV‐1 activation during myocardial reperfusion injury

Abstract

Cardiac reperfusion injury has been implicated in tissue damage caused when blood supply returns after the ischemia. During the reperfusion injury, transient receptor potential channel 1 (TRPV1) mediates cellular responses to stress such as heat, pain, and noxious stimuli. TRPV1 gates calcium and can regulate mitochondrial membrane potential. We hypothesize that the TRPV1 channel and its interaction with calcineurin have a specific role in mediating cardiac cellular injury. To test the hypothesis, adult cardiomyocytes from male Sprague-Dawley rats (225–300grams) were isolated and subjected to hypoxia-reoxygenation for one and two hours, respectively. Isolated adult cardiomyocytes were further treated with cell-permeable peptides and underwent cell death assays such as LDH measurement and Trypan Blue staining to measure cell viability. Moreover, flow cytometry assay was performed to identify the apoptotic rate of cell death upon peptide treatment. According to the results, AnnexinV-FITC/PI double staining demonstrates that cardiomyocytes undergoing hypoxia and reoxygenation (HR) enter the early apoptotic state more frequently than the necrotic state. There is also a significant two-fold difference between normoxia and HR groups in detecting the apoptotic rate. Synthesized peptide against the TRPV1-calcineurin interaction site, V1-cal, maintains a higher level of cell viability when cardiomyocytes were subjected to HR. V1-cal reduces the injury after hypoxia and reoxygenation in primary cardiomyocytes. These data reveal that TRPV1 has a significant role in cardioprotection. On a larger scale, controlling the interaction site between TRPV1 and calcineurin can possibly limit the reperfusion injury. Support or Funding Information The authors would like to thank American Physiological Society (APS) for providing financial support to Z. Zhanzak as a UGREF at Stanford University, School of Medicine, Department of Anesthesiology, Perioperative and Pain Medicine under the supervision of Professor Eric Gross. Annexin V-FITC/PI double staining flow cytometry of primary cardiomyocytes to detect apoptotic rate. LDH assay on primary adult cardiomyocytes Trypan Blue assay on H9C2 cells Immunofluorescence assay on transfected H9C2 cells. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.