Byrne, E.H., Farcasanu, M., Bloom, S., Xulu, N., Xu, J., Handley, S., Bramante, J., Mitchell, C., Villani, A.-C., and Kwon, D.S.
Background: Injectable progestin-only contraceptives (IPCs), including Depo-Provera (DMPA), have been associated with HIV acquisition risk in some epidemiological studies and in animal models. This risk has not been consistently observed and the risk of IPCs must be weighed against the known benefits of effective contraception. Regardless, understanding how IPCs shape the mucosal environment of the female genital tract can help elucidate biological mechanisms underlying their potential impact on HIV acquisition risk and may lead to new HIV prevention strategies. Methods: Cervical cytobrushes were collected from HIV-uninfected women aged 18 to 23 years through the FRESH (Females Rising through Education, Support, and Health) study in Umlazi, South Africa, and cervical epithelial and CD4+ T cells were FACS-sorted. RNAseq was performed on the sorted cells and data was analyzed using STAR, HTSeq, DESeq2, and GSEA. Results: Cervical epithelial cells were compared between women who reported using DMPA (n = 6) and women in the follicular phase of the menstrual cycle by reported last menstrual period (n = 6). tSNE clustering showed clear segregation between groups, and 369 genes were significantly differentially expressed. Of these genes, two of the most highly expressed in DMPA users were CCL3 and CCL3L3, mediators of T cell homing. GSEA analysis demonstrated that the epithelial gene sets most significantly over-expressed in DMPA-using women were keratinization, cellular response to IFNg, and keratinocyte differentiation (FDR q < 0.05). Parallel analysis of cervical CD4+ T cells identified 5 significantly differentially expressed genes (fold change >90) and a significantly enriched gene set in DMPA users, 'positive regulation of T cell mediated immunity' (FDR q-val 0.087). Conclusions: In DMPA users, cervical epithelial cells express higher levels of the T cell homing cytokines CCL3 and CCL3L3, while cervical CD4+ T cells exhibit inflammatory gene set enrichment. At the same time, keratinization pathways may be altered in DMPA users, as suggested in previous literature. Together, these results suggest possible mechanisms by which progestins may contribute to genital inflammation and/or differential barrier function in the genital mucosa. These findings may point towards potential biological approaches to reduce HIV acquisition risk in women., OA19.03 E.H. Byrne (1); M. Farcasanu (2); S. Bloom (3); N. Xulu (4); J. Xu (2); S. Handley (5); J. Bramante (2); C. Mitchell (6); A.-C. Villani (7) and D.S. [...]