ABSTRACT
PURPOSE: To test if nicotine counteracts the dampening effect of human cytomegalovirus (HCMV) infection of NF-kappaB in retinal pigment epithelial (RPE) cells, thereby increasing the permissiveness of RPE cells for HCMV replication. METHODS: Human ARPE-19 cells were transfected with NF-kappaB luciferase DNA, inoculated with HCMV at 24 hr post-transfection, and maintained in the absence or presence of a physiologic dose of nicotine at 1 hr prior to HCMV inoculation. RESULTS: Whereas HCMV-infected ARPE-19 cells without nicotine treatment showed a dramatic decrease in NF-kappaB levels, nicotine treatment reduced this decrease but did not abolish it completely. Nicotine treatment of uninfected ARPE-19 cells had no effect on baseline NF-kappaB levels. CONCLUSIONS: Treatment of HCMV-infected ARPE-19 cells with nicotine at a physiologic dose dampened the downregulation of NF-kappaB observed in HCMV-infected ARPE-19 cells without nicotine treatment. We conclude that nicotine can serve as a cofactor to stimulate productive, lytic replication of HCMV.
Subject(s)
Cytomegalovirus/physiology , Gene Expression/physiology , NF-kappa B/genetics , Nicotine/pharmacology , Nicotinic Agonists/pharmacology , Pigment Epithelium of Eye/drug effects , Pigment Epithelium of Eye/virology , Blotting, Western , Cell Line , Humans , NF-kappa B/metabolism , Pigment Epithelium of Eye/metabolism , Transfection , Virus ReplicationABSTRACT
To examine the mechanism of HIV-1 regulation by NF-IL6 in activated human cells, we selected a Jurkat cell line that did not contain endogenous NF-IL6. In this cellular environment, we evaluated the effect of exogenous NF-IL6 on transcription mediated by native and deleted LTR sequences. In Jurkat cells stimulated with LPS and PMA, LTR-mediated transcription was enhanced by NF-IL6. The results of deletion studies revealed a central role for the basal LTR region and the TATA element in the LTR, in upregulation of reporter gene expression by NF-IL6 in activated cells. In the selected cellular environment, regulation of transcription by NF-IL6 was not evident in studies of promoter regions of other genes. The results implied that the basal region of HIV-1 LTR includes molecular properties that support activation of HIV-1 by NF-IL6 in stimulated cells.
