Myoblast mitochondrial respiration is decreased in chronic binge alcohol administered simian immunodeficiency virus-infected antiretroviral-treated rhesus macaques

Abstract

Work from our group demonstrated that chronic binge alcohol (CBA)‐induces mitochondrial gene dysregulation at end‐stage disease of simian immunodeficiency virus (SIV) infection in antiretroviral therapy (ART) naïve rhesus macaques. Alterations in gene expression can disrupt mitochondrial homeostasis and in turn contribute to the risk of metabolic comorbidities characterized by loss of skeletal muscle (SKM) functional mass that are associated with CBA, human immunodeficiency virus (HIV) infection, and prolonged ART. The aim of this study was to examine the interaction of CBA and ART on SKM fiber oxidative capacity and myoblast mitochondrial respiration in asymptomatic SIV‐infected macaques. SKM biopsies were obtained and myoblasts isolated at baseline and 11 months post‐SIV infection from CBA/SIV/ART+ and from sucrose (SUC)‐treated SIV‐infected (SUC/SIV/ART+) macaques. CBA and ART decreased succinate dehydrogenase (SDH) activity in type 1 and type 2b fibers as determined by immunohistochemistry. Myoblasts isolated from CBA/SIV/ART+ macaques showed decreased maximal oxygen consumption rate (OCR) compared to myoblasts from control macaques. Maximal OCR was significantly increased in control myoblasts following incubation with formoterol, a beta adrenergic agonist, and this was associated with increased PGC‐1α expression and mtDNA quantity. Additionally, formoterol treatment of myoblasts isolated from CBA/SIV/ART+ macaques partially restored maximal OCR to levels not significantly different from control. These results show that CBA in combination with ART impairs myoblast mitochondrial homeostasis in SIV‐infected macaques. Moreover, our findings suggest that adrenergic agonists can potentially ameliorate mitochondrial dysfunction. Future studies will elucidate whether physical exercise in HIV patients with alcohol use disorder can improve mitochondrial health.

Differential contribution of chronic binge alcohol and antiretroviral therapy to metabolic dysregulation in SIV-infected male macaques

“…There was an ART-mediated increase in hepatic gene expression of key gluconeogenic and fatty acid synthesis enzymes. This adds to our previous reports of CBA-mediated decreases in AIRg, DI, circulating adiponectin levels (20), in vitro differentiation potential of skeletal muscle myoblasts (58), and mitochondrial function in skeletal muscle and myoblasts (18) (Fig. 7).…”

“…However, our tightly controlled studies allow the outcome measures to reflect alterations because of the manipulated variables and suggest an ART (nucleoside reverse transcriptase inhibitor, NRTI)-mediated metabolic dysregulation. Though the current study did not focus on mitochondrial function in the liver and adipose tissue, we recently published that alcohol and SIV mediate mitochondrial dysfunction in skeletal muscle myoblasts, even in ARTtreated, virally suppressed SIV-infected macaques (18). It is suggested that cells with mitochondrial dysfunction promote cell survival by activating the AMPK pathway and autophagy (71).…”

“…This was characterized by increased skeletal muscle proteasomal activity, attenuation of anabolic pathways, alterations in insulin signaling (35), a profibrotic milieu (17), dysregulation of gene networks that regulate muscle homeostasis (59), and altered mitochondrial function (19). Our recent work also provides evidence that CBA decreases myoblast differentiation (58) and dysregulates mitochondrial function (18) in ART-treated macaques. These findings suggest that CBA potentially affects skeletal muscle insulin responsiveness in SIV-infected animals.…”

HEMA 3 Staining: A Simple Alternative for the Assessment of Myoblast Differentiation

“…Subsequent analysis will depend on experimental design. Myoblasts or differentiated myotubes can also be used for other downstream applications including assessing mitochondrial function (Duplanty et al, 2018) and anabolic functions such as insulin-responsive glucose uptake and protein synthesis.…”

“…This protocol provides a method for isolating primary myoblasts from skeletal muscle tissue. We have successfully used this protocol to isolate PAX7 + /integrin α7 + myoblasts from rhesus macaque (Duplanty, Siggins, Allerton, Simon, & Molina, 2018;Simon et al, 2014), human, rat, and mice (unpublished) skeletal muscle. After washing muscle tissue, mechanical and enzymatic means are used to disrupt the tissue.…”