Nucleoside Reverse Transcriptase Inhibitors Induce a Mitophagy-Associated Endothelial Cytotoxicity That Is Reversed by Coenzyme Q10 Cotreatment

Abstract

Cardiovascular complications have been documented in HIV-1 infected populations, and antiretroviral therapy may play a role. Nucleoside reverse transcriptase inhibitors (NRTIs) are antiretrovirals known to induce mitochondrial damage in endothelial cells, culminating in endothelial dysfunction, an initiating event in atherogenesis. Though the mechanism for NRTI-induced endothelial toxicity is not yet clear, our prior work suggested that a mitochondrial oxidative stress may be involved. To further delineate the mechanism of toxicity, endothelial cells were treated with NRTIs of varying subclasses, and the level of reactive oxygen species (ROS) and mitochondrial function were assessed. To test whether rescue of mitochondrial electron transport attenuated NRTI-induced endothelial cytotoxicity, in some cases, cells were cotreated with the electron transport cofactor coenzyme Q10 (Q10). At 4-6h, NRTIs increased levels of ROS but decreased the activities of electron transport chain complexes I-IV, levels of ATP and the NAD/NADH ratio. Moreover, nitric oxide levels were decreased, whereas endothelin-1 release was increased. Q10 abolished NRTI-induced mitochondria injury and effects on endothelial agonist production. Interestingly, in cells treated with NRTIs only, markers for mitochondrial toxicity returned to baseline levels by 18-24h, suggesting a compensatory mechanism for clearing damaged mitochondria. Using confocal microscopy, with confirmation utilizing the autophagy and mitophagy markers LC-3 and Nix, respectively, we observed autophagy of mitochondria at 8-10h after treatment. Q10 prevented NRTI-mediated increase in LC-3. These findings suggest that NRTI-induced mitophagy may be involved in NRTI-induced endothelial dysfunction and that this damage likely results from oxidant injury. Further, Q10 supplementation could potentially prevent NRTI-induced endothelial dysfunction.

Overexpression of mitochondrial antioxidant manganese superoxide dismutase (MnSOD) provides protection against AZT- or 3TC-induced endothelial dysfunction

“…However, while renal and other tissue toxicities are believed to be mediated by mitochondrial oxidative stress (Abraham et al, 2013; Duong Van Huyen et al, 2003; Jiang et al, 2009; Kohler et al, 2009), our studies indicate that targeted antioxidants may also be useful in preventing other NRTI side effects. Our in vitro studies support the concept of adding coenzyme Q10 to current therapies (Xue et al, 2013). Unfortunately, variable results in effects of CoQ10 treatments for mitochondrial diseases have been reported, presumably due to low bioavailability in plasma and tissues after administration (Molyneux et al, 2008; Wyman et al, 2010).…”

“…In pathological conditions, however, ET-1 production may be increased, not only by endothelial cells, but also in other types of cells, including smooth muscle cells and macrophages (Bohm and Pernow, 2007). Prior work in our laboratory demonstrated that treatment of endothelial cells with AZT, 3TC, or tenofovir induces increases in ET-1 in vitro and that co-treatment with the antioxidant coenzyme Q10 prevents this increase (Xue et al, 2013). In the current study, WT and transgenic mice treated with AZT and 3TC paralleled the in vitro results.…”

“…Additionally, these cells generated increased reactive oxygen species (ROS), reduced ATP production, and decreased electron transport chain activity, suggesting that mitochondrial oxidative stress is a key player in this dysfunction (Xue et al, 2013). Oxidative stress occurs when the production of ROS exceeds the ability of antioxidants to scavenge and neutralize them.…”

Nucleoside/nucleotide reverse transcriptase inhibitors attenuate angiogenesis and lymphangiogenesis by impairing receptor tyrosine kinases signalling in endothelial cells

“…Only cells from passages 3–8 were used for experiments. The 10 μM doses of drugs were carefully selected according to the International US AIDS Panel, and the average plasma drug concentrations were as previously reported (Chittick et al, ; Jiang et al, ; Xue et al, ). For all in vitro experiments, the cells were treated with drugs for 48 h prior to testing.…”

Effect of rosuvastatin on plasma coenzyme Q10 in HIV-infected individuals on antiretroviral therapy

“…One study conducted before effective ART showed no statistically significant difference in CoQ10 levels between HIV-infected patients and uninfected controls 28 . More recently, there is evidence that CoQ10 supplementation may ameliorate the neurotoxicity and endothelial dysfunction associated with the use of mitochondrial toxic ART 31–32 . No study has examined CoQ10 changes in response to statin therapy in chronic HIV infection.…”