HIV infection of macrophages is enhanced in the presence of increased expression of CD163 induced by substance P. Issue 1 (27th February 2014) - Tuluc, Florin
Abstract : HIV infection in macrophages is enhanced by substance P through a mechanism dependent on the haptoglobinhemoglobin scavenger receptor CD163. ABSTRACT: Activation of NK1R by SP contributes to increased HIV-1 infection in macrophages. The scavenger receptor CD163 is expressed on cells of monocyte-macrophage origin. Our main goal was to determine if there is interplay among SP, CD163 expression, and HIV infection in macrophages. We showed that SP triggers intracellular calcium elevation and increased CD163 expression in human monocytes in a time- and concentration-dependent manner. The role of CD163 on HIV infection was examined by RT-PCR in sorted monocytes (CD163 low and CD163 high ) and in macrophages having CD163 knocked down using siRNA. We found that the productivity of HIV infection was higher in CD163 high cells. Additionally, in macrophages with CD163 expression knocked down, we found a significant decrease of HIV infection. Furthermore, Hb-Hp complexes, which function as an endogenous ligand for CD163, decreased HIV infection in macrophages in a dose-dependent manner. Thus, we demonstrate that SP induces higher levels of CD163 in monocytes and that high expression of CD163 is associated with increases HIV infection in macrophages. Thus, in addition to being a prognostic marker of HIV infection, the expression of CD163 on macrophages may be critical in HIV immunopathogenesis.