A Synthetic Epoxydocosapentaenoic Acid Analogue Ameliorates Cardiac Ischemia/Reperfusion Injury: The Involvement of the Sirtuin 3-NLRP3 Pathway
Authors: John R Falck
Adeniyi Michael Adebesin
Abdul Sattar Mohammad
John M Seubert
Ahmed M Darwesh
Wesam Bassiouni
Journal: International Journal of Molecular Sciences (2020)
Discipline: CHEMISTRY
Keywords: EDP surrogates; NLRP3 inflammasome; Sirtuin 3; cardioprotection; ischemia-reperfusion injury
Affiliations: Faculty of Pharmacy and Pharmaceutical Sciences, 2026-M Katz Group Centre for Pharmacy and Health Research, University of Alberta, 11361-97 Ave, Edmonton, AB T6G 2E1, Canada., Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB T6G 2E1, Canada., Division of Chemistry, Departments of Biochemistry and Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.

Abstract:  While survival rates have markedly improved following cardiac ischemia-reperfusion (IR) injury, the resulting heart damage remains an important issue. Preserving mitochondrial quality and limiting NLRP3 inflammasome activation is an approach to limit IR injury, in which the mitochondrial deacetylase sirtuin 3 (SIRT3) has a role. Recent data demonstrate cytochrome P450 (CYP450)-derived epoxy metabolites, epoxydocosapentaenoic acids (EDPs), of docosahexaenoic acid (DHA), attenuate cardiac IR injury. EDPs undergo rapid removal and inactivation by enzymatic and non-enzymatic processes. The current study hypothesizes that the cardioprotective effects of the synthetic EDP surrogates AS-27, SA-26 and AA-4 against IR injury involve activation of SIRT3. Isolated hearts from wild type (WT) mice were perfused in the Langendorff mode with vehicle, AS-27, SA-26 or AA-4. Improved postischemic functional recovery, maintained cardiac ATP levels, reduced oxidative stress and attenuation of NLRP3 activation were observed in hearts perfused with the analogue SA-26. Assessment of cardiac mitochondria demonstrated SA-26 preserved SIRT3 activity and reduced acetylation of manganese superoxide dismutase (MnSOD) suggesting enhanced antioxidant capacity. Together, these data demonstrate that the cardioprotective effects of the EDP analogue SA-26 against IR injury involve preservation of mitochondrial SIRT3 activity, which attenuates a detrimental innate NLRP3 inflammasome response. 

Retracted: No

PubPeer comments:
 The same VDAC loading control was used in panels 3A, 4A, 4B, 4D, 4E, 5A, and 5C (please see the marked image below). Could the authors please explain? ![file] , 
 #1 First, we would like to thank you for your valuable and important question. Second, we would like to highlight the following points: 1- Basically, we detected all these proteins in the isolated mitochondrial fractions and so we used VDAC as a loading control, and these are just representative blots. VDAC was run on all mitochondria blots and relative expression changes were quantified. 2- We assessed the same proteins on each blot, we have N=4-5 repeat experiments blots. Importantly, you can detect up to 8 proteins on the same blot after efficient stripping and blocking especially if the proteins are at different molecular weights (Please take a look at the attached examples for detecting up to 8 proteins on the same blot) u2022 Bhansali, S., Bhansali, A., Dhawan, V. (2020). Metformin promotes mitophagy in mononuclear cells: a potential in vitro model for unraveling metformin s mechanism of action. Ann N Y Acad Sci, 1463, 23-36. u2022 Espinosa-Garcia, C., Atif, F., Yousuf, S., Sayeed, I., Neigh, G. N., Stein, D. G. (2020). Progesterone Attenuates Stress-Induced NLRP3 Inflammasome Activation and Enhances Autophagy following Ischemic Brain Injury. Int J Mol Sci, 21. Finally, again, we would like to thank you for your important question and greatly appreciate the opportunity to respond to the comment. ,