Sex Hormones and Aging Modulate Interferon Lambda 1 Production and Signaling by Human Uterine Epithelial Cells and Fibroblasts.

Estradiol (E2) and progesterone (P) have potent effects on immune function in the human uterine endometrium which is essential for creating an environment conducive for successful reproduction. Type III/lambda (λ) interferons (IFN) are implicated in immune defense of the placenta against viral pathogens, which occurs against the backdrop of high E2 and P levels. However, the effect of E2 and P in modulating the expression and function of IFNλ1 in the non-pregnant human uterine endometrium is unknown. We generated purified in vitro cultures of human uterine epithelial cells and stromal fibroblast cells recovered from hysterectomy specimens. Poly (I:C), a viral dsRNA mimic, potently increased secretion of IFNλ1 by both epithelial cells and fibroblasts. The secretion of IFNλ1 by epithelial cells significantly increased with increasing age following poly (I:C) stimulation. Stimulation of either cell type with E2 (5x10-8M) or P (1x10-7M) had no effect on expression or secretion of IFNλ1 either alone or in the presence of poly (I:C). E2 suppressed the IFNλ1-induced upregulation of the antiviral IFN-stimulated genes (ISGs) MxA, OAS2 and ISG15 in epithelial cells, but not fibroblasts. Estrogen receptor alpha (ERα) blockade using Raloxifene indicated that E2 mediated its inhibitory effects on ISG expression via ERα. In contrast to E2, P potentiated the upregulation of ISG15 in response to IFNλ1 but had no effect on MxA and OAS2 in epithelial cells. Our results demonstrate that the effects of E2 and P on IFNλ1-induced ISGs are cell-type specific. E2-mediated suppression, and selective P-mediated stimulation, of IFNλ1-induced ISG expression in uterine epithelial cells suggest that the effects of IFNλ1 varies with menstrual cycle stage, pregnancy, and menopausal status. The suppressive effect of E2 could be a potential mechanism by which ascending pathogens from the lower reproductive tract can infect the pregnant and non-pregnant endometrium.

Neutrophil extracellular traps prevent HIV infection in the female genital tract.

Women acquire human immunodeficiency virus (HIV) mainly through sexual intercourse. However, low transmission rates per sexual act indicate that local immune mechanisms contribute to HIV prevention. Neutrophils represent 10-20% of the genital immune cells in healthy women. Neutrophils mediate mucosal protection against bacterial and fungal pathogens through different mechanisms, including the release of neutrophil extracellular traps (NETs). NETs are DNA fragments associated with antimicrobial granular proteins. Despite neutrophil abundance and central contributions to innate immunity in the genital tract, their role in protection against HIV acquisition is unknown. We found that stimulation of human genital neutrophils with HIV viral-like particles (HIV-VLPs) induced NET release within minutes of viral exposure, through reactive oxygen species-independent mechanisms that resulted in immediate entrapment of HIV-VLPs. Incubation of infectious HIV with pre-formed genital NETs prevented infection of susceptible cells through irreversible viral inactivation. HIV inactivation by NETs from genital neutrophils could represent a previously unrecognized form of mucosal protection against HIV acquisition.

Isolation of Dendritic Cells from the Human Female Reproductive Tract for Phenotypical and Functional Studies.

The characterization of the human dendritic cells (DCs) resident in mucosal tissues is challenging due to the difficulty in obtaining samples, and the low numbers of DCs present per tissue. Yet, as the phenotype and function of DCs is modified by the tissue environment, it is necessary to analyze tissue resident DC populations, since blood derived DCs incompletely reflect the complexities of DCs in tissues. Here we present a protocol to isolate DCs from the human female reproductive tract (FRT) using hysterectomy specimens that allows both phenotypical and functional analyses. The protocol consists of tissue digestion to generate a single cell mixed cell suspension, followed by positive magnetic bead selection. Our tissue digestion protocol does not cleave surface markers, which allows phenotypical and functional analysis of DCs in the steady state, without overnight incubation or cell activation. This protocol can be adapted for the isolation of other immune cell types or isolation of DCs from other tissues.

Aging impacts CD103+ CD8+ T cell presence and induction by dendritic cells in the genital tract.

As women age, susceptibility to systemic and genital infections increases. Tissue-resident memory T cells (TRMs) are CD103+ CD8+ long-lived lymphocytes that provide critical mucosal immune protection. Mucosal dendritic cells (DCs) are known to induce CD103 expression on CD8+ T cells. While CD103+ CD8+ T cells are found throughout the female reproductive tract (FRT), the extent to which aging impacts their presence and induction by DCs remains unknown. Using hysterectomy tissues, we found that endometrial CD103+ CD8+ T cells were increased in postmenopausal compared to premenopausal women. Endometrial DCs from postmenopausal women were significantly more effective at inducing CD103 expression on allogeneic naïve CD8+ T cells than DCs from premenopausal women; CD103 upregulation was mediated through membrane-bound TGFß signaling. In contrast, cervical CD103+ T cells and DC numbers declined in postmenopausal women with age. Decreases in DCs correlated with decreased CD103+ T cells in endocervix, but not ectocervix. Our findings demonstrate a previously unrecognized compartmentalization of TRMs in the FRT of postmenopausal women, with loss of TRMs and DCs in the cervix with aging, and increased TRMs and DC induction capacity in the endometrium. These findings are relevant to understanding immune protection in the FRT and to the design of vaccines for women of all ages.

Menopausal status influences the expression of programmed death (PD)-1 and its ligand PD-L1 on immune cells from the human female reproductive tract.

PROBLEM: The programmed death 1 (PD-1)/PD-L1 pathway regulates peripheral tolerance, immune responses, and is up-regulated in chronic viral infections, including HIV infection. However, expression of PD-1/PD-L1 on immune cells from the human female reproductive tract (FRT) and possible regulation by menopause and sex hormones are poorly understood. METHOD OF STUDY: PD-1/PD-L1 expression was analyzed on CD4(+) and CD8(+) T cells, CD163(+) macrophages, and CD11c(+) dendritic cells (DC) from endometrium (EM), endocervix (CX) and ectocervix (ECX). Expression after hormone treatment in culture was also evaluated. RESULTS: PD-1 and PD-L1 were constitutively expressed on CD4(+) and CD8(+) T cells from the FRT. PD-L1(+) CD4(+) T cells were increased in CX compared to EM and ECX, while no differences were found for PD-1 or between CD8(+) T cells from different sites. Macrophages and DCs constitutively expressed PD-L1, but not PD-1, with no differences observed between FRT sites. Pre-menopausal FRT tissues showed increased PD-L1 expression on CD8(+) T cells, but decreased expression on DCs when compared to post-menopausal women. In vitro estradiol treatment up-regulated PD-L1 expression specifically on CD8(+) T cells from CX, but had no effect on PD-1/PD-L1 expression on the other cell types. CONCLUSION: Our results suggest that PD-L1 may be involved in the differential regulation of FRT immune responses between pre-menopausal and post-menopausal women.

Estradiol reduces susceptibility of CD4+ T cells and macrophages to HIV-infection.

The magnitude of the HIV epidemic in women requires urgent efforts to find effective preventive methods. Even though sex hormones have been described to influence HIV infection in epidemiological studies and regulate different immune responses that may affect HIV infection, the direct role that female sex hormones play in altering the susceptibility of target cells to HIV-infection is largely unknown. Here we evaluated the direct effect of 17-ß-estradiol (E2) and ethinyl estradiol (EE) in HIV-infection of CD4(+) T-cells and macrophages. Purified CD4(+) T-cells and monocyte-derived macrophages were generated in vitro from peripheral blood and infected with R5 and X4 viruses. Treatment of CD4(+) T-cells and macrophages with E2 prior to viral challenge reduced their susceptibility to HIV infection in a dose-dependent manner. Addition of E2 2 h after viral challenge however did not result in reduced infection. In contrast, EE reduced infection in macrophages to a lesser extent than E2 and had no effect on CD4(+) T-cell infection. Reduction of HIV-infection induced by E2 in CD4(+) T-cells was not due to CCR5 down-regulation, but was an entry-mediated mechanism since infection with VSV-G pseudotyped HIV was not modified by E2. In macrophages, despite the lack of an effect of E2 on CCR5 expression, E2-treatment reduced viral entry 2 h after challenge and increased MIP-1ß secretion. These results demonstrate the direct effect of E2 on susceptibility of HIV-target cells to infection and indicate that inhibition of target cell infection involves cell-entry related mechanisms.

Disruption of histone modification and CARM1 recruitment by arsenic represses transcription at glucocorticoid receptor-regulated promoters.

Chronic exposure to inorganic arsenic (iAs) found in the environment is one of the most significant and widespread environmental health risks in the U.S. and throughout the world. It is associated with a broad range of health effects from cancer to diabetes as well as reproductive and developmental anomalies. This diversity of diseases can also result from disruption of metabolic and other cellular processes regulated by steroid hormone receptors via aberrant transcriptional regulation. Significantly, exposure to iAs inhibits steroid hormone-mediated gene activation. iAs exposure is associated with disease, but is also used therapeutically to treat specific cancers complicating an understanding of iAs action. Transcriptional activation by steroid hormone receptors is accompanied by changes in histone and non-histone protein post-translational modification (PTM) that result from the enzymatic activity of coactivator and corepressor proteins such as GRIP1 and CARM1. This study addresses how iAs represses steroid receptor-regulated gene transcription. PTMs on histones H3 and H4 at the glucocorticoid receptor (GR)-activated mouse mammary tumor virus (MMTV) promoter were identified by chromatin immunoprecipitation analysis following exposure to steroid hormone+/-iAs. Histone H3K18 and H3R17 amino acid residues had significantly different patterns of PTMs after treatment with iAs. Promoter interaction of the coactivator CARM1 was disrupted, but the interaction of GRIP1, a p160 coactivator through which CARM1 interacts with a promoter, was intact. Over-expression of CARM1 was able to fully restore and GRIP1 partially restored iAs-repressed transcription indicating that these coactivators are functionally associated with iAs-mediated transcriptional repression. Both are essential for robust transcription at steroid hormone regulated genes and both are associated with disease when inappropriately expressed. We postulate that iAs effects on CARM1 and GRIP1 may underlie some of its therapeutic effects and as well be associated with its toxic effects.