Cell type-specific expression of estrogen and progesterone receptors in the human vaginal mucosa

Sex hormone signaling and regulation of immune function

Immune responses to antigens, including innocuous, self, tumor, microbial, and vaccine antigens, differ between males and females. The quest to uncover the mechanisms for biological sex differences in the immune system has intensified, with considerable literature pointing toward sex hormonal influences on immune cell function. Sex steroids, including estrogens, androgens, and progestins, have profound effects on immune function. As such, drastic changes in sex steroid concentrations that occur with aging (e.g., after puberty or during the menopause transition) or pregnancy impact immune responses and the pathogenesis of immune-related diseases. The effect of sex steroids on immunity involves both the concentration of the ligand and the density and distribution of genomic and nongenomic receptors that serve as transcriptional regulators of immune cellular responses to affect autoimmunity, allergy, infectious diseases, cancers, and responses to vaccines. The next frontier will be harnessing these effects of sex steroids to improve therapeutic outcomes.

Complex Extract of Polygonatum sibiricum and Nelumbinis semen Improves Menopause Symptoms via Regulation of Estrogen Receptor Beta in an Ovariectomized Rat Model

Menopause is a hormone-deficiency state that causes facial flushing, vaginal dryness, depression, anxiety, insomnia, obesity, osteoporosis, and cardiovascular disease as ovarian function decreases. Hormone-replacement therapy is mainly used to treat menopause; however, its long-term use is accompanied by side effects such as breast cancer and endometriosis. To identify the effect of a complex extract of Polygonatum sibiricum (PS) and Nelumbinis semen (NS) on improving menopause without side effects, an ovariectomized rat model was established to analyze several menopause symptoms. Compared to single extracts, the complex extract restored vaginal epithelial cell thickness and decreased serotonin concentration by increasing the estrogen receptors ERα (ESR1) and ERβ (ESR2), depending on the ratio. Although the complex extract exerted a lower weight-loss effect than the single extracts, improved blood-lipid metabolism was observed after increasing high-density lipoprotein cholesterol levels and decreasing low-density lipoprotein cholesterol and triglyceride levels, and ovariectomy-induced osteoporosis was alleviated by suppressing osteoclast production. Thus, by increasing only ERβ expression without regulating ERα expression in the uterus, the complex extract of PS and NS may be a natural treatment for improving menopause symptoms without side effects, such as endometriosis.

Differential expression of nuclear hormone receptors by dendritic cell subsets in human vaginal mucosa and skin

Nuclear hormone receptors (NHRs) expressed by dendritic cells (DCs), the major immune inducers and regulators, could play important roles in host immunity. Assessment of NHRs expressed by DCs in the vaginal mucosa (VM), in comparison with those expressed by DCs in other tissues, will thus help us understand the immunology of human vagina. This study identified 16 NHR transcripts that are differentially expressed among 8 different antigen-presenting cell (APC) subsets isolated from human VM, skin, and blood. The expression profiles of NHRs were largely tissue specific. VM APCs expressed increased levels of LXRA, RXRA, ESRRA, ESRRAP2, and PPARG, whereas skin and blood APCs expressed increased levels of NURR1, NOR1 and RARA. Of interest, female sex hormone receptors, ESR1 and PGR, were found to be mainly expressed by non-APC cell types in the VM; ESR1 by HLA-DR⁺CD34⁺ and PGR by HLA-DR^- cells. ERα and PR were expressed by vimentin⁺ cells in the VM, but not in human skin. ERα, but not PR, was also expressed in CD10⁺ cells in the lamina propria of VM. In conclusion, NHR expression by APC subsets is tissue- and cell type-specific. Future studies on the roles of individual NHRs expressed by different cell types, including DC subsets, in the human VM are warranted.

Female Reproductive Systems: Hormone Dependence and Receptor Expression

The female reproductive system which consists of the ovaries, uterus (myometrium, endometrium), Fallopian tubes, cervix and vagina is exquisitely sensitive to the actions of steroid hormones. The ovaries play a key role in the synthesis of bioactive steroids (oestrogens, androgens, progestins) that act both within the tissue (intracrine/paracrine) as well as on other reproductive organs following release into the blood stream (endocrine action). Sex steroid receptors encoded by the oestrogen (ESR1, ESR2), progesterone (PR) and androgen (AR) receptor genes, which are members of the superfamily of ligand activated transcription factors are widely expressed within these tissues. These receptors play critical role(s) in regulation of cell proliferation, ovulation, endometrial receptivity, myometrial cell function and inflammatory cell infiltration. Our understanding of their importance has been informed by studies on human tissues and cells, which have employed immunohistochemistry as well as a wide range of molecular and genetic methods to identify which processes are dependent steroid ligand activation. The development of mice with targeted deletions of each of these receptors has provided complementary data that has extended our appreciation of cell-cell interactions in the fine tuning of reproductive tissue function. This large body of work has formed the basis of new and improved therapeutics to treat conditions such as infertility.