Hormonal Contraceptives Drive Genital Lipid Metabolism Reprogramming and Susceptibility to HIV Infection

Heterosexual genital HIV transmission is a major driver of new infections, particularly in women, making them disproportionately vulnerable to HIV acquisition. Previous studies have associated injectable hormonal contraceptives (HC) with increasing susceptibility to HIV. Yet, the underlying molecular mechanism remains incompletely understood. Given the structural and signaling role of lipids in the female genital tract, cervicovaginal lipidomic profiling has the potential to reveal the mechanistic interplay among HC, lipidome, and HIV susceptibility in the female genital tract. We conducted untargeted cervicovaginal lipidomics study in a cohort of high-risk, HIV-negative, Kenyan sex workers who were using injectable depot medroxyprogesterone acetate (DMPA), oral contraceptive pill (OCP), or no hormonal contraception (NH). Genital lipids were quantitatively analyzed using liquid chromatography-mass spectrometry (LC-MS) and bioinformatics platforms. A total of 1045 lipid species were identified in the cervicovaginal lavage samples. Injectable DMPA significantly downregulated major structural and signaling membrane lipids, including phospholipids, ceramides, sphingomyelins, and glycosphingolipids (p<0.001, FDR<0.05), and markedly upregulated storage lipids (triglycerides) and sterols when compared with OCP or NH groups. Interestingly, microbial communities contributed significantly to the DMPA-driven genital lipidomic shifting, suggesting the intricate interplay among sex hormones, microbiome, and lipidome. In contrast, OCP, which contains estrogen, consistently lowered genital triglycerides and increased the fatty acid and diacylglycerol substrates compared with the NH group, implying that estrogen affects genital lipid metabolism by contrasting the lipogenesis effect of DMPA. Differential lipidomic pathway analysis further confirmed that DMPA suppressed the de novo phospholipid and sphingolipid biosynthesis, but enhanced salvaging of various lipids from reaction intermediates and from cell membrane lipid pool, shifting them towards TG accumulation. Our findings of dysregulated depletion of several membrane and signaling phospholipids, ceramides, sphingomyelins, glycosphingolipids, along with upregulation of triglycerides in the DMPA users provides insights into the underlying molecular mechanism by which DMPA may increase in susceptibility to HIV infection by weakening the epithelial barrier and increasing chronic inflammation. These findings underscore the need to address cervicovaginal lipidomic dysregulation associated with HCs while designing interventions to improve the reproductive health of women. Key Words: Lipidomics, hormonal contraceptives, LC-MS, phospholipids, sphingolipids, HIV susceptibility, microbial lipids, pathway analysis