Abstract
The expression of CXCR4, a membrane protein which is involved in the entry of HIV-1, is down-modulated from the cell surface by Phorbol 12-myristate 13-acetate (PMA) and the Ca+ ionophore, Ionomycin. Inducible co-stimulator (ICOS), which contributes to lymphocyte proliferation, is up-regulated by PMA/Ionomycin. We examined the influence of S-nitrosoglutathione (SNG), an inhibitor of Vacuolar H+-ATPase (V-ATPase), on the expression of CXCR4 and ICOS in PMA/Ionomycin-treated peripheral mononuclear cells (PBMC), and of CXCR4 alone in lymphoid cell lines. In this report, we show that SNG interferes with both effects of PMA/Ionomycin, namely CXCR4 down-regulation and ICOS up-regulation. These studies imply opposing roles of V-ATPase in the regulation of CXCR4 and ICOS. The influence of SNG in modulating the susceptibility of T cells to HIV-1 and on their immune responses needs further investigation.
Key words: S-nitrosoglutathione (SNG), CXCR4, ICOS, HIV-1
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Abbreviations used
- SNG
S-nitrosoglutathione
- PMA
phorbol 12-myristate 13-acetate
- V-ATPase
vacuolar H+-ATPase
- ICOS
inducible co-stimulator
- HIV
human immunodeficiency virus
- CCP
clathlin-coated pit
- PBMC
peripheral mononuclear cells
- GRK
G-protein coupled receptor kinase
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