Targeted myocardial transgenic expression of HIV Tat causes cardiomyopathy and mitochondrial damage

Abstract

Cardiac effects of human immunodeficiency virus (HIV) transactivator (Tat) are unclear, but Tat decreases liver glutathione (an important mitochondrial antioxidant) when ubiquitously expressed in transgenic mice (TG). With an alpha-myosin heavy chain promoter, Tat was selectively targeted to murine cardiac myocytes. One high-expression hemizygous ((+/-)Tat(high); 12 copies) and two low-expression ((+/-)Tat(lowA,B); 2-5 copies) TG lines were created. Cardiomyopathy was documented with increased left ventricle (LV) mass, ventricular expression of atrial natriuretic factor (ANF) mRNA, mitochondrial ultrastructural defects, and myocardial depletion of glutathione. In (+/-)Tat(high) TGs, normalized LV mass (determined echocardiographically) increased 46% (90 days), 134% (240 days), and 96% (365 days) compared with wild-type littermates (WT). LV fractional shortening was decreased to 28% (90 days), 27% (240 days), and 19% (365 days). (+/-)Tat(low) LV mass was unchanged (<or=365 days). ANF in (+/-)Tat(high) ventricles (180 days) was twofold WT values. Glutathione was selectively decreased in (+/-)Tat(high) hearts (120 days). (+/-)Tat(high) hearts contained damaged mitochondria (>or=210 days); however, profound mitochondrial destruction occurred in homozygous (+/+)Tat(high) hearts (10 days) and the pups died (14 days). Tat caused cardiac dysfunction in this TG and may impact on cardiomyopathy in acquired immunodeficiency syndrome.

HIV viral protein R causes atrial cardiomyocyte mitosis, mesenchymal tumor, dysrhythmia, and heart failure

“…Although indirectly supportive, findings from TGs with cardiac-targeted Nef and Vpu each independently yielded no cardiac structural or functional phenotype. Taken together with the findings from the Vpr TGs, and our previous findings in which an oxidative stress phenotype was observed in cardiac-targeted HIV Tat, 13 the Vpr TG here offers insights into effects of other HIV structural and accessory proteins on cardiac function and structure.…”

“…13 For Southern blotting, 10 mg of mouse genomic tail DNA was digested overnight at 371C. The digested DNA was subjected to electrophoresis in a 0.7% agarose gel and transferred to a positively charged nylon membrane (Schleicher & Schuell, Keene, NH, USA) overnight.…”

“…13 Total RNA was extracted from mouse tissues with TRI reagent (Molecular Research, Cincinnati, OH, USA). RNA (10 mg) was subjected to electrophoresis with the NorthernMax kit (Ambion, Austin, TX, USA) in a 1% agarose gel and transferred to a positively charged nylon membrane (Roche Applied Science) overnight.…”

Transgenic expression of the deoxynucleotide carrier causes mitochondrial damage that is enhanced by NRTIs for AIDS

“…6 A 963-bp fragment containing the human DNC gene was amplified using the primers DNC5 0 and DNC3 0 and cloned into a pBluescript 5K vector. The a-MyHC clone 26 (compliments of Jeff Robbins, Children's Research Foundation, Cincinnati, OH, USA 7 ) was digested with SalI and HindIII (Roche Applied Science, Indianapolis, IN, USA) to facilitate construction of the final vector.…”

“…6 Echocardiography (ECHO) in DNC TG and WT For ECHO observations in the HAART protocols with AZT backbone, TG þ AZT HAART N ¼ 9;…”