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We hypothesized that competition between NRTI-triphosphate and endogenous deoxyribonucleoside triphosphate (dNTP) may lead to depletion of dNTP pools and mitochondrial dysfunction independent of Pol-γ inhibition. We collected peripheral blood mononuclear cells from 75 adults (25 cases: HIV-infected with mitochondrial toxicity, 25 HIV-infected positive controls, and 25 HIV-negative controls). We observed statistically significant individual and group differences in ribonucleotide (RN) and deoxyribonucleotide (dRN) pools. The median RN pool was 10062 (IQR, 7090 – 12590), 4360 (IQR, 3058 –6838), and 2968 (IQR, 2538 – 4436) pmol/106 cells for negative controls, positive controls, and cases, respectively. Cases had significantly higher absolute mtDNA copy number compared to negative controls (p<0.05). Cases had significantly higher expression of Pol-γ, nucleoside transporters, cellular kinases, and ABC compared to controls. Antiretroviral therapy perturbs ribonucleotide and deoxyribonucleotide pools. Depletion of RN and dRN pools may be associated with ART-induced mitochondrial toxicity independent of Pol-γ inhibition.

Highlights d HSPCs exhibit post-transcriptional and translational mechanisms of gene regulation d mTOR is targeted for proteasomal degradation in myeloid progenitors by c-Cbl d CDK1 regulates the activation of eIF4E-dependent translation in myeloid progenitors d Aberrant mTOR expression in myeloid progenitors results in increased myeloid cells

ObjectivesWe recently observed a decrease in deoxyribonucleotide (dNTP) pools in HIV‐infected individuals on antiretroviral therapy (ART). Alterations in dNTPs result in mutations in mitochondrial DNA (mtDNA) in cell culture and animal models. Therefore, we investigated whether ART is associated with mitochondrial genome sequence variation in peripheral blood mononuclear cells (PBMCs) of HIV‐infected treatment‐experienced individuals.MethodsIn this substudy of a case−control study, 71 participants were included: 22 ‘cases’, who were HIV‐infected treatment‐experienced patients with mitochondrial toxicity, 25 HIV‐infected treatment‐experienced patients without mitochondrial toxicity, and 24 HIV‐uninfected controls. Total DNA was extracted from PBMCs and purified polymerase chain reaction (PCR) products were subjected to third‐generation sequencing using the PacBio Single Molecule Real‐Time (SMRT) sequencing technology. The sequences were aligned against the revised Cambridge reference sequence for human mitochondrial DNA (NC_012920.1) for detection of variants.ResultsWe identified a total of 123 novel variants, 39 of them in the coding region. HIV‐infected treatment‐experienced patients with and without toxicity had significantly higher average numbers of mitochondrial variants per participant than HIV‐uninfected controls. We observed a higher burden of mtDNA large‐scale deletions in HIV‐infected treatment‐experienced patients with toxicity compared with HIV‐uninfected controls (P = 0.02). The frequency of mtDNA molecules containing a common deletion (mt.δ4977) was higher in HIV‐infected treatment‐experienced patients with toxicity compared with HIV‐uninfected controls (P = 0.06). There was no statistically significant difference in mtDNA variants between HIV‐infected treatment‐experienced patients with and without toxicity.ConclusionsThe frequency of mtDNA variants (mutations and large‐scale deletions) was higher in HIV‐infected treatment‐experienced patients with or without ART‐induced toxicity than in uninfected controls.