RESUMO
BACKGROUND: HIV triggers the decline of CD4+ T cells and leads to progressive dysfunction of cell-mediated immunity. Although an increased susceptibility to cell death occurs during the acute phase of HIV infection, persistently-infected macrophages and quiescent T-cells seem to be resistant to cell death, representing a potential reservoir for virus production. RESULTS: Lymphoid (H9/HTLVIIIB and J1.1) and pro-monocytic (U1) HIV-1 persistently-infected cell lines were treated with hydrogen peroxide (H2O2) and staurosporine (STS) for 24 h, and susceptibility to apoptosis was evaluated and compared with uninfected counterparts (H9, Jurkat and U937 respectively). When exposed to different pro-apoptotic stimuli, all persistently-infected cell lines showed a dramatic reduction in the frequency of apoptotic cells in comparison with uninfected cells. This effect was independent of the magnitude of viral replication, since the induction of viral production in lymphoid or pro-monocytic cells by exposure to TNF-alpha or PMA did not significantly change their susceptibility to H2O2- or STS-induced cell death. A mechanistic analysis revealed significant diferences in mitochondrial membrane potential (MMP) and caspase-3 activation between uninfected and persistently-infected cells. In addition, Western blot assays showed a dramatic reduction of the levels of pro-apototic Bax in mitochondria of persistently-infected cells treated with H2O2 or STS, but not in uninfected cells. CONCLUSION: This study represents the first evidence showing that resistance to apoptosis in persistently-infected lymphoid and monocytic cells is independent of active viral production and involves modulation of the mitochondrial pathway. Understanding this effect is critical to specifically target the persistence of viral reservoirs, and provide insights for future therapeutic strategies in order to promote complete viral eradication.
Assuntos
Apoptose/fisiologia , Infecções por HIV/patologia , Infecções por HIV/virologia , HIV-1/fisiologia , Mitocôndrias/fisiologia , Antivirais/farmacologia , Apoptose/efeitos dos fármacos , Western Blotting , Caspase 3/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Citometria de Fluxo , Humanos , Peróxido de Hidrogênio/farmacologia , Células Jurkat , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/virologia , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Estaurosporina/farmacologia , Linfócitos T/virologia , Células U937 , Replicação Viral , Proteína X Associada a bcl-2/metabolismoRESUMO
Sexually transmitted infections (STIs) have shown to enhance the transmission of human immunodeficiency virus (HIV) and to be more common among female commercial sex workers (FSWs). A cross-sectional study was conducted among 625 FSWs in six cities of Argentina in 2000-2002. The seroprevalence of HIV, hepatitis B virus (HBV), hepatitis C virus (HCV), human T-cell lymphotropic virus type I/II, and syphilis was 3.2%, 14.4%, 4.3%, 1.6%, and 45.7%, respectively. Syphilis was associated with older age (>/= 30 years, adjusted odds ratio [AOR] = 2.6 to 4.9), >/= 10 years in sex work (AOR = 2.2), use of illegal drugs (AOR = 2.1), and a prior history of an STI (AOR = 3.0). HBV and syphilis was the most common co-infection in 44 (7.5%) subjects. FSWs in Argentina are exposed to HIV and other STIs due to high-risk sexual and illegal drug use behavior. Renewed efforts are necessary to intervene effectively in this high-risk population.