HIV-1 gp120-mediated increases in IL-8 production in astrocytes are mediated through the NF-κB pathway and can be silenced by gp120-specific siRNA

Background: the exact mechanism underlying hiv-associated neurocognitive disorders still remains largely unresolved. however,viral genes (for example gp120 and tat) and their effect on cytokine/chemokine expressions have been linked with neuroinflammation. conversely,interlekin-8 (il-8) is a known proinflammatory chemokine and is known to be over-expressed in human brain microvascular endothelial cells in response to gp120. in this study,we sought to address whether hiv-1gp120 could affect il-8 expression in astrocytes and whether the nf-κb pathway is involved in this phenomenon.methods: svga astrocytes were transfected with a plasmid expressing hiv-1 psyn gp120 jr-fl using lipofectamine2000. the cells were harvested at different time points after transfection,and total cellular rna was used for quantification of il-8 using a real time pcr. il-8 protein expression was also determined in supernatants collected at different time points after transfection. involvement of the nf-κb pathway was addressed using both pharmacological inhibitors and an sirna approach. in order to explore gene specificity,gp120-specific sirnas were designed and il-8 expression was monitored at both mrna and protein levels.results: gp120 increased il-8 expression both at mrna and protein levels by 7.1 ± 1.04 and 2.41 ± 0.35 fold at 6 and 48 hours post-transfection,respectively. this increase was time-dependent and was abrogated by use of gp120-specific sirna. we have also shown that the nf-κb pathway is involved in gp120-mediated il-8 overexpression as ikk-2 and ikkβ inhibitors inhibited il-8 expression by 63.5% and 57.5%,respectively at the mrna level,and by 67.3% and 58.6% at the protein level. these results were also confirmed with use of nf-κb-specific sirna.conclusion: these results indicate that gp120 can modulate expression of a pro-inflammatory chemokine (il-8) in astrocytes in a time-dependent manner with significant up-regulation at different times. this phenomenon is specific and is mediated by the nf-κb pathway. © 2010 shah and kumar; licensee biomed central ltd.