ASSOCIATION OF IMMUNE DYSFUNCTION WITH MICROBIAL DYNAMICS AND ABERRANT ESTROGEN METABOLISM IN REPRODUCTIVE DISORDERS

Author

Nhung Xuan Hong Le, Southern Illinois University CarbondaleFollow

Date of Award

6-1-2021

Degree Name

Doctor of Philosophy

Department

Molecular Biology, Microbiology and Biochemistry

First Advisor

Torry, Donald

Second Advisor

Braudmeier-Fleming, Andrea

Abstract

Chronic inflammation is associated with the pathophysiology of obstetrical disorders (e.g. preterm birth [PTB]) and gynecological diseases (e.g. endometriosis); however, the exact mechanism(s) for these conditions are unknown. Numerous immunological conditions and disease states (e.g. inflammatory bowel disease, Crohn’s disease, systemic lupus erythematomus) also disrupt the microbiome homeostasis by inducing a number of changes in the microbial flora when compared to that of healthy individuals. Furthermore, the gastrointestinal (GI) microbiome is one of the principal regulators of circulating estrogens which are known to directly impact the female reproductive disorders endometriosis and PTB. Thus, an alteration of microbial species could indicate a shift in immune balance from homeostatic to pro-inflammatory, and an aberrant estrogen metabolism that precipitates the development of disease stages in endometriosis and/or PTB. The Braundmeier-Fleming lab has developed a systems biology model that investigates the interactions between the immune system, microbial dynamics (in the GI and reproductive system) and estrogen metabolism, in women, as a potential diagnostic tool for endometriosis and PTB. This dissertation, therefore, examined how inflammation triggered by female reproductive disorders (endometriosis or PTB) alter the systemic and localization immune responses, the microbial communities in the urogenital (UG), peritoneal and GI mucosal epithelium, as well as levels of excreted conjugated estrogen. The first specific hypothesis is that inflammation associated with endometriosis alters microbial dynamics and functions that are distinct from those of non-diseased patients. Preliminary data indicated that reproductive tract microbial communities from patients with endometriosis are unique when compared to non-disease patients. Therefore, the central aims of this study are to identify the immune and microbial profiles of patients diagnosed with endometriosis and determine if an alteration of these profiles impact estrogen signaling, thus driving disease pathogenesis. Additionally, I hypothesized that surgery or hormonal therapy will temporarily restore the microbiome and estrogen levels of patients with endometriosis. Differences in systemic (blood) regulatory T cell (Treg) and T-helper 17 (Th17) cell populations (tolerant and inflammatory, respectively) were measured by flow cytometry, and the immune mediators was measured by serum cytokine levels via 10-plex-ELISA kits. Immunohistochemistry was used to identify resident Th17/Treg immune cell distribution within the endometrium and ectopic endometriotic lesions, and RORγt+/FOXP3+ transcripts within these same tissues were analyzed by real-time-qPCR. We implemented high-throughput non genomic sequencing targeting bacterial-V4 16S rRNA and robust bioinformatics analyses to characterize microbial composition/diversity within the GI (fecal swab), vaginal (vaginal swab), and UG (urine) cavities. Alterations in estrogen metabolism, parent estrogens and metabolites, in urine were analyzed via LC-MS/MS. Patients with endometriosis exhibit 1) systemic and localized inflammation within ectopic and endometrial tissues, 2) altered GI/UG microbial dynamics, 3) aberrant levels of endogenous estrogen and estrogen metabolites, 4) dampened inflammation (caused by disease) due to hormonal therapy, 5) altered bacteria populations in the gut and vaginal canal of patients with endometriosis due to hormonal therapy treatment, and 6) increased post-surgical variability in microbial community dynamics. The second specific aims examined the hypothesis that induction of endometriosis in baboons (P. Anubis) results in chronic systemic and tissue specific inflammation through regulation of Th17 and Treg populations. Further, the induction of endometriosis altered GI/UG/peritoneal cavity microbial communities that are distinct from non-diseased animals. Utilizing a non-human primate animal model of induced endometriosis allowed us to characterize factors involved at the early onset of endometriosis and throughout the disease progression. We collected samples from 8 baboons at pre-inoculation (no evidence of disease) and at 3, 6, 9, and 15 months post-induction of the disease. We found that the induction of endometriosis decreased peripheral Tregs cells while Th17 cells increased at all post-induction collections with reduced ratio of total Tregs to Th17 cells indicating systemic inflammation. Microbial community diversities as well as abundances at each sample site (GI, UG [vagina, urine] tracts and peritoneal cavity) were also altered at post-induction. These results therefore suggest that induction of endometriosis in non-human primates caused an inflammatory shift. Disease induction also resulted in altered vaginal, urinary and fecal microbial profiles, which may drive inflammation through the production of inflammatory mediators. The last specific aims studied the hypothesis that patients who deliver preterm have a systemic and placental inflammatory phenotype and abnormal estrogen levels during pregnancy that are distinct from those of patients with term delivery. Biological samples were collected at 8-12 weeks, 20-24 weeks, 32-36 weeks, at delivery and 6 weeks postpartum. Subjects with PTB showed signs of systemic inflammation with an elevation in Th17:Treg ratio, greater Th17 and lower levels of natural Tregs during the 2nd trimester, and lower inducible Tregs during the 3rd trimester and at delivery. Placental tissues from subjects with PTB also had an inflammatory immune phenotype (higher Th17) within the decidua basalis and maternal-fetal interface. Immunological shifts from tolerant to inflammatory were observed in both patient groups, but these shifts occurred early in gestation for subjects with PTB and at a later gestational age for subjects delivering at term. Levels of conjugated parent estrogens and estrogen metabolites were reduced in subjects with PTB, indicative of an abnormal production of estrogen. These analyses gave us a better understanding of the inflammatory cascade with estrogen metabolism associated with pregnancy, and how these effects are correlated with premature labor. The data from this study suggest that the levels of endogenous estrogen and estrogen metabolites of estrogen metabolism were abnormal in PTB and endometriosis disease models of inflammation compared to their respective controls. In the human and non-human primate model of endometriosis studies, we observed that both patients and baboons with endometriosis had systemic and resident inflammatory phenotypes and an alteration in mucosal microbial community dynamics compared to their respective controls. All together, our long-term goal is to identify factors from the microbiome and/or the immune system that would allow us to have early non-invasive diagnostics for endometriosis or to predict which mothers are most at risk to encounter PTB. Furthermore, it would allow us to determine whether the mucosal microbiome may be a good indicator of immune stress, and if alternative therapies can alter microbial community dynamics—thereby eliminating immune stress associated with female reproductive diseases. These findings may have a substantial impact on the obstetrical care and management of patients with endometriosis and women at risk for PTB, as well as provide evidence to support the development of novel therapeutics to treat these diseases.