Targeted Mitochondrial COQ₁₀ Delivery Attenuates Antiretroviral-Drug-Induced Senescence of Neural Progenitor Cells

Abstract

HIV infection is associated with symptoms of accelerated or accentuated aging that are likely to be driven not only by HIV itself but also by the toxicity of long-term use of antiretroviral drugs. Therefore, it is crucially important to understand the mechanisms by which antiretroviral drugs may contribute to aging. The aim of this study was to investigate the hypothesis that antiretroviral drugs cause increased reactive oxygen species (ROS) generation that results in mitochondrial dysfunction and culminates in promoting cellular senescence. In addition, we applied targeted nanoparticle (NP)-based delivery to specifically enrich mitochondria with coenzyme Q10 (CoQ10) in order to enhance antioxidant protection. The studies employed neural progenitor cells (NPCs), as differentiation of these cells into mature neurons is affected both during HIV infection and in the aging process. Exposure of cultured NPCs to various combinations of HIV antiretroviral therapy (ART) induced a more than 2-fold increase in mitochondrial ROS generation and mitochondrial membrane potential, a more than 50% decrease in oxygen consumption and ATP levels, a 60% decrease in SIRT3 expression, and a 42% decrease in cell proliferation relative to control levels. These alterations were accompanied by a 37% increase in beta-galactosidase staining and a shortening of the telomere length to more than half of the length of controls as assessed by quantitative telomere-FISH labeling, indicating accelerated NPC senescence in response to ART exposure. Importantly, CoQ10 delivered by targeted nanoparticles effectively attenuated these effects. Overall, these results indicate that ART promotes cellular senescence by causing mitochondrial dysfunction, which can be successfully reversed by supplementation with mitochondria-targeted CoQ10.

A guide to assessing cellular senescence in vitro and in vivo

“…As introduced above, mitochondria have been used as a druggable target in senescence, with drugs and nanoparticles directed at specific mitochondrial moieties. For example, Tri-phenyl Phosphine (TPP), a lipophilic cation moiety that targets mitochondria with increased membrane potential [74], has been re-engineered as MitoTam (combined with a modified version of Tamoxifen) and as part of polymer-based nanoparticles named PLGA to efficiently target senescent cells [75,76]. Further, a gold nanoparticle system, in which TPP was used in conjunction with the surface marker B2MG, has been reported to specifically target senescence as well [73].…”

Therapeutic Strategies for Regulating Mitochondrial Oxidative Stress

“…The dendrimers successfully accumulated in mitochondria of the activated microglia at the site of the injury, contributing to the removal of ROS. A TPP-modified PLGA carrier encapsulating CoQ 10 has been reported to prevent and treat neurocognitive impairment, which is a symptom of HIV and is a side effect associated with multidrug therapy [85]. Treatment of mouse or human neural progenitor cells (NPCs) with a TPP-modified PLGA carrier encapsulating CoQ 10 before treatment with anti-HIV drugs resulted in a significant reduction in the amount of ROS.…”

Cerebral Vascular Toxicity of Antiretroviral Therapy

“…Because of the close interactions between the BBB and NPCs, we extended our studies on ART-induced dysfunction of the brain endothelium to other cells of the neurovascular unit and/or the cells that are located in the immediate proximity of the BBB. Our recently published study indicated that exposure to ART causes increased reactive oxygen species (ROS) generation which results in mitochondrial dysfunction, thus promoting cellular senescence (Velichkovska et al 2018 ). The study employed several ART combinations, such as Tenofovir and Emtricitabine (both nucleoside reverse transcriptase inhibitors, NRTIs), Tenofovir, Emtricitabine, and Raltegravir (NRTIs plus a protease inhibitor), and Tenofovir, Emtricitabine, Ritonavir, and Darunavir (NRTIs plus integrase inhibitors).…”

“…Inhibition of its function has in fact been associated with the pathogenesis of neurodegenerative diseases (Schapira 2010 ). A commonly used research method to estimate electron transport chain function is measuring the oxygen consumption rate (OCR), and we (and others) have shown that ART drug combinations induce alternations of OCR (Apostolova et al 2015a ; Cohen et al 2017 ; Velichkovska et al 2018 ). An interesting observation also indicates that the inhibition of Complex I and alterations to the electron transport chain function may occur without any changes in the OCR levels (Ciavatta et al 2017 ).…”

“…There is extensive evidence for oxidative stress induction in correlation with ART in different brain cell types and as the result of exposure to different antiretroviral drug classes (Mollace et al 2001 ; Steiner et al 2006 ). The human brain microvascular endothelial cell line (hCMEC/D3) was shown to exhibit increased ROS as well as mitochondrial superoxide levels after exposure to Zidovudine and Indinavir (Prasad et al 2016 ), and both of these parameters were also increased due to Tenofovir, Emtricitabine, Ritonavir, and Darunavir (NRTIs, protease, and integrase inhibitors combination) exposure to NPCs (Velichkovska et al 2018 ). Furthermore, as a representative of a potent NRTIs, Zalcitabine was found to increase oxidative stress in isolated mitochondria and synaptosomes as indicated by alternations of protein carbonyls and 3-nitrotyrosine levels (Opii et al 2007 ).…”