HIV-1 Protein Tat 1–72 Impairs Neuronal Dendrites via Activation of PP1 and Regulation of the CREB/BDNF Pathway

Abstract

Despite the success of combined antiretroviral therapy in recent years, the prevalence of human immunodeficiency virus (HIV)-associated neurocognitive disorders in people living with HIV-1 is increasing, significantly reducing the health-related quality of their lives. Although neurons cannot be infected by HIV-1, shed viral proteins such as transactivator of transcription (Tat) can cause dendritic damage. However, the detailed molecular mechanism of Tat-induced neuronal impairment remains unknown. In this study, we first showed that recombinant Tat (1–72 aa) induced neurotoxicity in primary cultured mouse neurons. Second, exposure to Tat_1–72 was shown to reduce the length and number of dendrites in cultured neurons. Third, Tat_1–72 (0–6 h) modulates protein phosphatase 1 (PP1) expression and enhances its activity by decreasing the phosphorylation level of PP1 at Thr320. Finally, Tat_1–72 (24 h) downregulates CREB activity and CREB-mediated gene (BDNF, c-fos, Egr-1) expression. Together, these findings suggest that Tat_1–72 might impair cognitive function by regulating the activity of PP1 and the CREB/BDNF pathway.

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