Azidothymidine-triphosphate impairs mitochondrial dynamics by disrupting the quality control system

• Published in: Redox biology Vol. 13; no. C; pp. 407 - 417
• Main Authors: Nomura, Ryosuke, Sato, Takeya, Sato, Yuka, Medin, Jeffrey A., Kushimoto, Shigeki, Yanagisawa, Teruyuki
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.2017; Elsevier
• Subjects: Animals; Anti-HIV Agents - adverse effects; Anti-HIV Agents - toxicity; Cardiomyopathy; Cardiotoxicity - etiology; Cell Line; Dynamins - genetics; Dynamins - metabolism; GTP Phosphohydrolases - genetics; GTP Phosphohydrolases - metabolism; Metabolites; Mitochondria - drug effects; Mitochondria - metabolism; Mitochondrial Dynamics; Mitochondrial function; Oxidative phosphorylation; Oxidative stress; Rats; Research Paper; Zidovudine - adverse effects; Zidovudine - toxicity; DHE; Oxidative stress; GTP; mtDNA; Cardiomyopathy; Mitochondrial dynamics; HRP; AZT-TP; IgG; FACS; Mff; mPTP; Drp1; DMEM; TMPK; calcein-AM; Mfn; Opa1; Metabolites; p-Drp1; Mitochondrial function; FBS; AZT-DP; cDNA; NRTI; WT; HPLC; MA-5; PBS; pol-γ; AZT-MP; HIV; Oxidative phosphorylation; ROS; nDNA; AZT; ATP; GAPDH; GTPase; HAART; JC-1; OCR
• ISSN: 2213-2317; 2213-2317
• DOI: 10.1016/j.redox.2017.06.011

Highly active anti-retrovirus therapy (HAART) has been used to block the progression and symptoms of human immunodeficiency virus infection. Although it decreases morbidity and mortality, clinical use of HAART has also been linked to various adverse effects such as severe cardiomyopathy resulting from compromised mitochondrial functioning. However, the mechanistic basis for these effects remains unclear. Here, we demonstrate that a key component of HAART, 3ꞌ-azido-3ꞌ-deoxythymidine (AZT), particularly, its active metabolite AZT-triphosphate (AZT-TP), caused mitochondrial dysfunction, leading to induction of cell death in H9c2 cells derived from rat embryonic myoblasts, which serve as a model for cardiomyopathy. Specifically, treatment with 100µM AZT for 48h disrupted the mitochondrial tubular network via accumulation of AZT-TP. The mRNA expression of dynamin-related protein (Drp)1 and the Drp1 receptor mitochondrial fission factor (Mff) was upregulated whereas that of optic atrophy 1 (Opa1) was downregulated following AZT treatment. Increased mitochondrial translocation of Drp1, Mff upregulation, and decreased functional Opa1 expression induced by AZT impaired the balance of mitochondrial fission vs. fusion. These data demonstrate that AZT-TP causes cell death by altering mitochondrial dynamics. •TMPK mutants efficiently converted AZT to its active metabolite AZT-TP.•Accumulated AZT-TP impaired mitochondrial network structure and dynamics.•AZT-TP but not AZT-MP caused mitochondrial dysfunction and ROS production.•Mitochondrial DNA copy number was unaffected by AZT-TP accumulation.•TMPK-expressing H9c2 cells are a suitable model for evaluating AZT toxicity.