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Investigating the Role of Mitochondrial Fission in Cardiac Myocyte Hypoxia/Re‐oxygenation‐Induced Cell Death
Author(s) -
Pratt Amina Malika,
Heine Erin,
Chen Qian,
Barsotti Robert,
Young Lindon
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.746.8
Subject(s) - mitochondrial fission , dnm1l , programmed cell death , mitochondrion , microbiology and biotechnology , apoptosis , chemistry , biology , biochemistry
Currently there is no effective pharmacological intervention to attenuate myocardial ischemia reperfusion (IR) injury. Understanding the mechanisms that govern IR injury would benefit myocardial infarction, coronary bypass and organ transplant patients. Recent studies suggest that cardiac mitochondria undergo excessive fragmentation during IR, a process that is called fission. Increased mitochondrial fission may lead to increased cell death during IR. Mitochondrial fission has been shown to be mediated by association of dynamin related protein‐1(Drp1), a GTPase that translocates from the cytosol to interact with outer mitochondrial membrane proteins, fission protein 1 and mitochondrial fission factor, to induce fission. We hypothesize that attenuating mitochondrial fission during IR may prove to be an effective strategy to mitigate IR injury. To test this hypothesis, we used a pharmacological inhibitor of Drp‐1 GTPase activity, Mdivi‐1(MW=353 g/mol). We subjected murine cardiac myocytes (HL‐1 cells) to 12 hours of hypoxia in hypoxic buffer (pH 6.8, no glucose or pyruvate) and then 1 hour of re‐oxygenation in normoxic media (pH 7.4), in the presence/absence of Mdivi‐1 (5–25μM). We predicted that HL‐1 cells subjected to simulated IR (SIR) would exhibit increased cell death in relation to their normoxic control counterparts, and that Mdivi‐1 treated cells would have attenuated SIR‐induced cell death. Cell death was determined by trypan blue (0.3%) staining. Preliminary data shows that control SIR cells (n=4) exhibited 25% cell death, by contrast Mdivi‐1 treated cells only showed 7% (5μM, n=4) and 11% (25μM n=4) cell death. Normoxic untreated (n=3) and Mdivi‐1 treated cells (5 and 25 μM; n=3) showed only 2% cell death in all study groups. The data suggests that inhibiting Drp‐1 may mitigate cardiac cell death during SIR. Future studies will determine the role of Drp‐1 in the regulation of mitochondrial dynamics during SIR. Support or Funding Information This study was supported by the Department of Bio‐Medical Sciences, Division of Research and the Center for Chronic Disorders of Aging at Philadelphia College of Osteopathic Medicine