Cardioprotective Properties of a Synthetic, Structurally Mimetic 19,20- Epoxydocosapentaenoic Acid Analog: Implications of SIRT3 Potentiation on Ischemia Reperfusion Injury

• Author / Creator

  Kranrod, Joshua W

• Mounting evidence suggests that CYP epoxygenase-derived metabolites of docosahexaenoic acid, called epoxydocosapentaenoic acids (EDPs), limit mitochondrial damage following cardiac injury. In particular, the 19,20-EDP regioisomer has demonstrated potent cardioprotective action. Thus, we investigated our novel synthetic 19,20-EDP analog SA-22 for protection against cardiac IR injury. Isolated C57BL/6J mouse hearts were perfused via Langendorff apparatus for 20 minutes to obtain baseline function followed by 30 minutes of global ischemia. Hearts were then treated with either vehicle, 19,20-EDP, SA-22, or SA-22 with the pan-sirtuin inhibitor nicotinamide (NAM), or the SIRT3-selective inhibitor 3-(1H-1,2,3-triazol-4-yl) pyridine (3-TYP) at the start of 40 minutes reperfusion (n = 5-8). We assessed IR injury-induced changes in recovery of myocardial function, using left ventricular developed pressure, systolic and diastolic pressure change. Tissues were assessed for electron transport chain (ETC) function, SIRT-1 and -3, optic atrophy type-1 (OPA1), and caspase-1. We also utilized H9c2 cells and neonatal rat cardiomyocytes (NRCMs) as in vitro models of hypoxia/reoxygenation injury. Perfusion with SA-22 significantly enhanced LVDP and dp/dt-max functional recovery (+50 percentage points) compared to vehicle alone, preserved ETC function, SIRT activity, and reduced activation of pyroptosis in response to IR and HR injury. Interestingly, while NAM co-treatment worsened functional outcomes, cell survival, and attenuated sirtuin activity, it failed to completely attenuate SA-22-induced protection against pyroptosis, possibly indicating EDPs exert cytoprotection through pleiotropic mechanisms. In short, these data demonstrate the potential of our novel synthetic 19,20-EDP analog SA-22 against IR/HR injury and justifies further development of therapeutic agents based upon 19,20-EDP.

• Subjects / Keywords

  • Epoxylipid
  • Ischemia
  • Analog
  • 19,20-EDP
  • Cardiac

• Graduation date

  Fall 2024

• Type of Item

  Thesis

• Degree

  Master of Science

• DOI

  https://doi.org/10.7939/r3-eb26-r114

• License

  This thesis is made available by the University of Alberta Library with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.