Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA.
Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA; Department of Pharmacology, Yale School of Medicine, New Haven, CT, USA; Department of Epidemiology & Public Health, Yale School of Public Health, New Haven, CT, USA.
Antiviral Res. 2020 Nov;183:104948. doi: 10.1016/j.antiviral.2020.104948. Epub 2020 Sep 24.
In clinical trials, the concentration of tenofovir diphosphate (TFV-DP) in peripheral mononuclear cells was 4 to 5-fold higher in individuals treated with tenofovir alafenamide (TAF) compared to individuals treated with tenofovir disoproxil fumarate (TDF). We hypothesized that the higher intracellular accumulation of TFV-DP could cause mitochondrial toxicity from either polymerase gamma (Pol-γ)-dependent or Pol-γ-independent mechanism(s). To test this hypothesis, we cultured human T lymphoblastoid cell line (CEM cells) for up to 12 days with TAF or TDF (multiplicities of C) to investigate the effects on mitochondrial function and respiration, and cholesterol biosynthesis. Both TAF and TDF treatments had no significant effect on cell growth, mitochondrial potential (ΔΨ), production of reactive oxygen species (ROS), and mitochondrial respiratory parameters. TAF had no statistically significant effect on expression of Pol-γ mRNA, mitochondria DNA (mtDNA) content, expression of proteins of the electron transport chain (ETC), and key genes of cholesterol biosynthesis. TDF had significant reduction in mtDNA content at 8xC, and statistically significant reduction in mRNA expression of squalene epoxidase (SQLE). Our findings do not support our hypothesis that the higher intracellular accumulation of TFV-DP in cells treated with TAF could cause mitochondrial dysfunction. In conclusion, our findings add to the emerging data that TAF may have a low potential for causing mitochondrial toxicity in HIV-infected individuals on TAF-containing regimens.
在临床试验中，与接受替诺福韦二吡呋酯（TDF）治疗的个体相比，接受替诺福韦艾拉酚胺（TAF）治疗的个体外周血单个核细胞中的替诺福韦二磷酸（TFV-DP）浓度高 4 至 5 倍。我们假设，TFV-DP 在细胞内的积累增加可能导致线粒体毒性，其机制可能依赖于聚合酶γ（Pol-γ）或不依赖于 Pol-γ。为了验证这一假设，我们用 TAF 或 TDF（C 的倍数）培养人 T 淋巴母细胞系（CEM 细胞）长达 12 天，以研究对线粒体功能和呼吸以及胆固醇生物合成的影响。TAF 和 TDF 处理均对细胞生长、线粒体膜电位（ΔΨ）、活性氧（ROS）的产生以及线粒体呼吸参数没有显著影响。TAF 对 Pol-γ mRNA 的表达、线粒体 DNA（mtDNA）含量、电子传递链（ETC）蛋白的表达以及胆固醇生物合成的关键基因均无统计学显著影响。TDF 在 8xC 时 mtDNA 含量显著降低，并且 SQLE（鲨烯环氧化酶）的 mRNA 表达显著降低。我们的研究结果不支持我们的假设，即 TAF 治疗组细胞内 TFV-DP 的积累增加可能导致线粒体功能障碍。总之，我们的研究结果进一步证实了 TAF 可能在接受 TAF 为基础方案治疗的 HIV 感染者中引起线粒体毒性的风险较低。
