Antiretroviral nucleosides, deoxynucleotide carrier and mitochondrial DNA: evidence supporting the DNA pol γ hypothesis

Abstract

NRTIs deplete mtDNA and polypeptides, cause mitochondrial structural and functional defects in vivo, follow inhibition kinetics with DNA pol gamma in vitro, and are corroborated by molecular models. Disrupted pools of nucleotide precursors and inhibition of DNA pol gamma by specific NRTIs are mechanistically important in mitochondrial toxicity.

Decreased mtDNA, oxidative stress, cardiomyopathy, and death from transgenic cardiac targeted human mutant polymerase γ

“…27,29,31,32 Genotyping For the TG line a-MyHC/Y955C, the presence of the mutant transgene was detected in the founders and their offspring using Southern blotting and real-time PCR essentially as recently described. 27,29,32 TG Gene Copy Analysis Four transgenic lines were established for the targeted overexpression of mutant POLG. To determine the relative copy number in each, the level of human Y955C POLG was analyzed semiquantitatively from tail DNA extracts using realtime PCR and Light Cycler TaqMan Master kit.…”

“…mtDNA and Nuclear DNA (nDNA) Quantitation in Heart Tissue from Y955C Pol c TGs Using Real-Time PCR Methods employed were based on modifications of those used by others 34,35 and detailed by us recently. 32 Briefly, DNA sequences for primers and probes used for quantization of mitochondrial and nuclear DNA with real-time PCR technique were adapted from others. 25 The accessory subunit of murine mitochondrial DNA polymerase gamma (ASPG) and mouse mitochondrial cytochrome oxidase subunit 1 (COX) were the subjects of separate quantization of mouse nuclear and mitochondrial DNA, respectively.…”

“…In those studies, TGs were treated with NRTIs that compete with native nucleotides for intramitochondrial phosphorylation and transport. 31,32,39,46,47 Data indicated transport of nucleotides into mitochondria may be disrupted by NRTIs.…”

“…Such mutations yield mtDNA depletion. 'Acquired mtDNA depletion' from administration of NRTIs for AIDS 31,32 offers a pharmacological model to deplete mtDNA in vivo. NRTI chemical structure, dose, and duration of therapy each impacted the extent of mtDNA depletion and tissue target.…”

Cardiovascular complications in the acquired immunodeficiency syndrome

“…Disrupted pools of nucleotide precursors and inhibition of DNA pol-gamma by specific nucleoside reverse transcriptase inhibitors are mechanistically important in mitochondrial toxicity 63 . This effect has been especially described with use of stavudine and was correlated with length of exposure to this drug 64 .…”