HIV-1 kills renal tubular epithelial cells in vitro by triggering an apoptotic pathway involving caspase activation and Fas upregulation.
HIV-infected patients suffer several renal syndromes, which can progress rapidly from renal insufficiency to end-stage renal disease. Histologically, HIV-induced nephropathy is characterized by prominent tubulopathy with apoptosis of tubular cells. Clinical and experimental evidence suggests that renal injury may be directly related to virus infection. Although HIV-1 is a polytropic and not solely lymphotropic pathogen, the susceptibility of renal cells to HIV-1 remains to be determined. This paper demonstrates in vitro the permissiveness of proximal tubular epithelial cells (PTEC) to HIV-1 and describes the effects of PTEC infection to explain the pathogenesis of tubular damage in vivo. The results indicate that PTEC express HIV-specific receptor and coreceptors and sustain virus replication. We observed that HIV-1 infection causes the death of tubular cells by triggering an apoptotic pathway involving caspase activation. Fas upregulation but not Fas ligand expression was found in the infected PTEC. However, after HIV-1 infection, tubular cells became susceptible to apoptosis induced through Fas stimulation. Caspase inhibition prevented the death of the infected PTEC in spite of persistent viral replication. These findings may explain the prominent histopathology of HIV-associated nephropathy and demonstrate that the apoptosis of nonlymphoid cells can be directly induced by HIV-1.
Conaldi
P G
PG
Division of Microbiology, Department of Clinical and Biological Sciences, University of Insubria, Varese 21100, Italy. pgiulio@working.it
Biancone
L
L
Bottelli
A
A
Wade-Evans
A
A
Racusen
L C
LC
Boccellino
M
M
Orlandi
V
V
Serra
C
C
Camussi
G
G
Toniolo
A
A
D017209:Apoptosis; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism*; D002470:Cell Survival; D002478:Cells, Cultured; D053938:DNA Fragmentation; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D053222:Fas Ligand Protein; D005434:Flow Cytometry; D016655:HIV Core Protein p24 / Q000378:metabolism; D015658:HIV Infections / Q000378:metabolism* / Q000473:pathology; D015497:HIV-1; D006651:Histocytochemistry; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology / Q000494:pharmacology; D007684:Kidney Tubules / Q000378:metabolism* / Q000473:pathology / Q000821:virology*; D008562:Membrane Glycoproteins / Q000378:metabolism*; D009842:Oligopeptides / Q000494:pharmacology; D015854:Up-Regulation
D004791:Enzyme Inhibitors; C505661:FASLG protein, human; D053222:Fas Ligand Protein; D016655:HIV Core Protein p24; D007075:Immunoglobulin M; D008562:Membrane Glycoproteins; D009842:Oligopeptides; C103712:benzyloxycarbonyl-valyl-alanyl-aspartyl-fluoromethane; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases