CHEMOKINE CXCL8 MODULATES HIV-1 REPLICATION IN HUMAN MONOCYTE-DERIVED MACROPHAGES

Purpose: Chemokine CXCL8 is an important neutrophil chemoattractant implicated in various neurodegenerative disorders. We previously reported that HIV-1 infection is linked to upregulation of CXCL8 in brain tissue. We also reported that SHP2 and MAPK pathways regulate the expression of CXCL8 in human astrocytes. In the post-ART era, low level of productive replication of HIV-1 in brain is a critical component of neuropathogenesis regulation. The present study investigated the effect of CXCL8 on productive infection of HIV-1 in human monocytes-derived macrophages (MDM). Methods: Human MDM were infected with blood and brain-derived HIV-1 isolates, HIVADA and HIVJR-FL. HIV p24 levels were assayed from culture supernatants with ELISA. DNA was isolated from infected cells treated with/without CXCL8 (10-100ng/ml) and amplified for two-LTR circles, as a measure of integration We employed human promonocytic cell line U937 as an efficient transfection system. U937 cells were transfected with pHIV-LTR and promoter activity was measured by luciferase reporter assay. Results: Treatment with CXCL8 led to significant upregulation (p<0.01) in HIV-1 p24 levels in supernatants of HIV-infected MDM, as determined by ELISA. Reverse transcriptase (RT) activity was significantly increased (p<0.01) in HIV-infected MDM treated with CXCL8. We compared the formation of 2-LTR circles in CXCL8 treated vs untreated HIV-infected MDM by RT-PCR, as a measure of viral genome integration. Transient transfection of U937 cells with HIV-LTR construct containing luciferase reporter gene resulted in increased luciferase activity when treated with CXCL8. Conclusions: The results show that CXCL8 mediates productive infection of HIV-1 in MDM and induces HIV-1 LTR promoter activity in U937 cells. Detailed understanding of the mechanisms involved could aid in therapeutic intervention strategies by modulating levels of this chemokine in the brain.