Stromal down-regulation of macrophage CD4/CCR5 expression and NF-κB activation mediates HIV-1 non-permissiveness in intestinal macrophages

PLoS Pathog. 2011 May;7(5):e1002060. doi: 10.1371/journal.ppat.1002060. Epub 2011 May 26.

Abstract

Tissue macrophages are derived exclusively from blood monocytes, which as monocyte-derived macrophages support HIV-1 replication. However, among human tissue macrophages only intestinal macrophages are non-permissive to HIV-1, suggesting that the unique microenvironment in human intestinal mucosa renders lamina propria macrophages non-permissive to HIV-1. We investigated this hypothesis using blood monocytes and intestinal extracellular matrix (stroma)-conditioned media (S-CM) to model the exposure of newly recruited monocytes and resident macrophages to lamina propria stroma, where the cells take up residence in the intestinal mucosa. Exposure of monocytes to S-CM blocked up-regulation of CD4 and CCR5 expression during monocyte differentiation into macrophages and inhibited productive HIV-1 infection in differentiated macrophages. Importantly, exposure of monocyte-derived macrophages simultaneously to S-CM and HIV-1 also inhibited viral replication, and sorted CD4+ intestinal macrophages, a proportion of which expressed CCR5+, did not support HIV-1 replication, indicating that the non-permissiveness to HIV-1 was not due to reduced receptor expression alone. Consistent with this conclusion, S-CM also potently inhibited replication of HIV-1 pseudotyped with vesicular stomatitis virus glycoprotein, which provides CD4/CCR5-independent entry. Neutralization of TGF-β in S-CM and recombinant TGF-β studies showed that stromal TGF-β inhibited macrophage nuclear translocation of NF-κB and HIV-1 replication. Thus, the profound inability of intestinal macrophages to support productive HIV-1 infection is likely the consequence of microenvironmental down-regulation of macrophage HIV-1 receptor/coreceptor expression and NF-κB activation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • CD4 Antigens / metabolism*
  • Cells, Cultured
  • Culture Media, Conditioned / pharmacology
  • Down-Regulation / physiology*
  • HIV-1 / isolation & purification
  • HIV-1 / pathogenicity
  • HIV-1 / physiology*
  • Humans
  • Intestinal Mucosa / virology*
  • Macrophages / cytology
  • Macrophages / drug effects
  • Macrophages / metabolism*
  • NF-kappa B / metabolism*
  • Receptors, CCR5 / metabolism*
  • Signal Transduction / physiology
  • Transforming Growth Factor beta / pharmacology
  • Virus Replication / drug effects
  • Virus Replication / physiology

Substances

  • CD4 Antigens
  • Culture Media, Conditioned
  • NF-kappa B
  • Receptors, CCR5
  • Transforming Growth Factor beta