Search

Elevated inflammatory cytokines (EMCs) at mucosal surfaces have been associated with HIV susceptibility, but the underlying mechanisms remain unclear. We characterized the soluble mucosal proteome associated with elevated cytokine expression in the female reproductive tract. A scoring system was devised based on the elevation (upper quartile) of at least three of seven inflammatory cytokines in cervicovaginal lavage. Using this score, HIV-uninfected Kenyan women were classified as either having EMC (n=28) or not (n=68). Of 455 proteins quantified in proteomic analyses, 53 were associated with EMC (5% false discovery rate threshold). EMCs were associated with proteases, cell motility, and actin cytoskeletal pathways, whereas protease inhibitor, epidermal cell differentiation, and cornified envelope pathways were decreased. Multivariate analysis identified an optimal signature of 16 proteins that distinguished the EMC group with 88% accuracy. Three proteins in this signature were neutrophil-associated proteases that correlated with many cytokines, especially GM-CSF (granulocyte-macrophage colony-stimulating factor), IL-1β (interleukin-1β), MIP-3α (macrophage inflammatory protein-3α), IL-17, and IL-8. Gene set enrichment analyses implicated activated immune cells; we verified experimentally that EMC women had an increased frequency of endocervical CD4(+) T cells. These data reveal strong linkages between mucosal cytokines, barrier function, proteases, and immune cell movement, and propose these as potential mechanisms that increase risk of HIV acquisition.

Introduction: Recent studies have identified Mx2 as a novel HIV-1 innate restriction factor that inhibits proviral integration. A pilot proteomic study of immune cells from highly exposed HIV-seronegative (HESN) individuals enrolled in the Pumwani sex worker cohort identified Mx1 as potential correlate of HIV protection. A detailed population level analysis of Mx1 and Mx2 expression and their role in reduced susceptibility to HIV infection in HESN women was conducted., Methods: Peripheral blood mononuclear cells (PBMC) were isolated from 102 HESN women and 100 high-risk negative controls enrolled in a Nairobi-based sex worker cohort. Whole-cell lysates were prepared and analyzed for Mx1 and Mx2 expression by commercial ELISA. Bivariate and multiple linear regression analyses were conducted to account for confounding epidemiological factors., Results: Mx2, but not Mx1, was found to be significantly overexpressed in HESN women compared with high-risk negative controls (P = 0.027). After multiple linear regression analysis, accounting for age, menopause, pregnancy, Depo-Provera use, recent infections and medication usage, Mx2 expression remained significantly overexpressed in the PBMC of HESN women (P = 0.05). Additionally, an interaction model analysis indicated that HESN women who use Depo-Provera have 2.6-fold higher levels of Mx2 than any other group (P < 0.001). No associations with Mx1 expression were observed., Conclusion: This is the first epidemiological report of Mx2 and its association with altered susceptibility to HIV infection in HESN women. Additionally, we show that HESN women who use Depo-Provera have the highest levels of Mx2 expression, highlighting a possible mechanism for hormonal modulation of HIV susceptibility.