IMPLICATIONS OF ASTROCYTIC NRF2-ARE SIGNALING PATHWAY IN METHAMPHETAMINE AND HIV-1gp120 INDUCED OXIDATIVE STRESS

Despite the advent of the antiretroviral therapy, HIV-1 associated neurocognitive disorders (HAND) continue to be a significant issue for HIV-1 infected patients. HIV-1 infection of CNS combined with Methamphetamine (METH) abuse causes overall increase in oxidative stress in astrocyte. In HAND patients, oxidative stress induced apoptosis in astrocyte compromises the normal physiology and function of CNS. NF-E2–related factor 2 (Nrf2) transcription factor plays vital role in cellular protective response against oxidative stress due to environmental agents such as electrophiles, drug abuse, smoking, radiation. Although HIV-1 gp120and METH have been implicated in the pathogenesis of HAND, little is known about their combined effect on the regulation of Nrf2 in human astrocytes. In this study, we investigated the combinatorial effect of gp120 and METH on Nrf2-ARE signaling pathway in primary human fetal astrocytes. Astrocytes were treated with METH and gp120 followed by immunocytochemistry analysis. The oxidative stress and apoptosis was detected by protein carbonylation and DNA fragmentation, respectively. The levels of phospho-Nrf2 and Nrf2 were analyzed by western blot. Repeated treatment of METH and gp120 induced the reactive astrocyte phenotype as observed by GFAP immunostaining. METH and gp120 significantly increased oxidative stress and apoptosis. Further investigation revealed that METH and gp120 significantly increased Nrf2 phosphorylation and nuclear translocation in a time-dependent manner. Taken together, these results suggest the involvement of Nrf2-ARE signaling pathway as a protective response to METH- and gp120- induced oxidative stress in human astrocytes. Purpose (a): Despite the advent of the antiretroviral therapy, HIV-1 associated neurocognitive disorders (HAND) continue to be a significant issue for HIV-1 infected patients. HIV-1 infection of CNS combined with Methamphetamine (METH) abuse causes overall increase in oxidative stress in astrocyte. In HAND patients, oxidative stress induced apoptosis in astrocyte compromises the normal physiology and function of CNS. NF-E2–related factor 2 (Nrf2) transcription factor plays vital role in cellular protective response against oxidative stress due to environmental agents such as electrophiles, drug abuse, smoking, radiation. Although HIV-1 gp120and METH have been implicated in the pathogenesis of HAND, little is known about their combined effect on the regulation of Nrf2 in human astrocytes. In this study, we investigated the combinatorial effect of gp120 and METH on Nrf2-ARE signaling pathway in primary human fetal astrocytes. Methods (b): Astrocytes were treated with METH and gp120 followed by immunocytochemistry analysis. The oxidative stress and apoptosis was detected by protein carbonylation and DNA fragmentation, respectively. The levels of phospho-Nrf2 and Nrf2 were analyzed by western blot. Results (c): Repeated treatment of METH and gp120 induced the reactive astrocyte phenotype as observed by GFAP immunostaining. METH and gp120 significantly increased oxidative stress and apoptosis. Further investigation revealed that METH and gp120 significantly increased Nrf2 phosphorylation and nuclear translocation in a time-dependent manner. Conclusions (d): Taken together, these results suggest the involvement of Nrf2-ARE signaling pathway as a protective response to METH- and gp120- induced oxidative stress in human astrocytes.