Topical Estrogen Treatment Augments the Vaginal Response to Escherichia coli Flagellin

Abstract

The female climacteric or menopausal process characterised by reduced estrogen, associates with an increased risk of recurrent urinary tract infections (rUtis) linked to uropathogenic Escherichia coli (UPEC). Clinically, topical vaginal estrogen treatment has a prophylactic effect against such infections. The aim of this study was to investigate, in vitro, the effects of a topical estrogen treatment on vaginal epithelial responses following challenge with E.coli flagellin mimicking an UPEC challenge. Immortalised vaginal epithelial cells (VK2 E6/E7), modelling the vaginal epithelium were treated with either 4 nM 17β-estradiol (E) for seven days, 50 ng/ml E.coli flagellin (F) for 12 h, or 4 nM 17β-estradiol plus 50 ng/ml flagellin (E + F(12 h)). RNA was analysed by microarray gene profiling using the Illumina HumanHT-12 v 4 Expression Beadchip. Following E + F treatments expression of genes encoding host defence molecules including DEFβ4A, DEFB103A, LCN2 as well as those associated with keratinisation eg CNFN and SPRR family genes were significantly enhanced (P < 0.05) compared to either E or F treatments alone. Mutation of estrogen responsive elements (EREs) identified in the DEFβ4 gene promoter abolished the augmented gene expression suggesting estrogen functioned directly through a regulatory mechanism involving ESR1/2. Ingenuity pathway analyses also suggested the proinflammatory cytokine IL-17A to regulate the vaginal host defences during infection. Pre-treating VK2 E6/E7 cells with estrogen (4 nM) and challenging with 1L-17A & F (12 h) significantly enhanced DEFβ4, DEF103A and S100A7 expression (P < 0.05). Origins of vaginal IL-17 in vivo remain unclear, but patient biopsies support γδ T cells located within the vaginal epithelium. These data suggest that the vaginal antimicrobial response induced by flagellin activation of Toll-like Receptor 5 cell signalling is augmented following topical estrogen application.

Urinary prostaglandin E2 as a biomarker for recurrent UTI in postmenopausal women

“…EHT has been shown to affect local immune responses ( Porter et al, 2001 ). Since EHT is common among postmenopausal women ( Stanton et al, 2020 ), we evaluated the association between urinary PGE 2 and EHT. Although no association was found between EHT and urinary PGE 2 concentration, only 29% of patients in the Relapse group used EHT compared to 62% and 53% of patients in the Remission and Never groups, respectively, ( Fig S7C and Table 3 ).…”

From Menopause to Neurodegeneration—Molecular Basis and Potential Therapy

“…Moreover, loss of ERα on epithelial cells also impairs the vaginal structural integrity and increases leukocyte infiltration [89]. These effects on the epithelium protect the vagina, urinary tract, and respiratory tract from infectious agents [90][91][92]. In addition to antimicrobial ability, estrogen can modulate gastrointestinal epithelial secretions [93].…”

Suprabasin—A Review

“…We predicted four FOXO1 binding sites within 2 kbp SBSN promoter region (relative score > 0.84; −1616/1609, −1668/−1661, −1692/−1685, −1930/−1923; Figure 3 ). Interestingly, SBSN promotes aromatase expression, and SBSN was shown to be induced with 17beta-estradiol treatment [ 31 ]. This is supported with the prediction of estrogen receptor (ER) binding sites within the promoter.…”

“…This suggests that the CNFN and SBSN -16-genes containing set could be functionally connected [ 53 ]. Previously, the estrogen biosynthesis and SBSN expression were linked via elevation of aromatase transcript levels in confluent ASCs [ 30 ] and induction of SBSN expression following 17beta-estradiol treatment of immortalized vaginal epithelial cells [ 31 ]. Importantly, SBSN in ASC-conditioned medium promoted migration of ER-negative breast carcinoma cell line MDA-MB-231 in an estrogen-independent manner [ 30 ].…”

“…Additionally, cancer therapy itself (e.g., γ-radiation or 5-AC) may promote SBSN expression [ 19 ]. Multiple reports showing SBSN transcript elevation should be broadened by uncovering the SBSN molecular role, for instance, in innate immune response [ 31 , 84 , 88 ], estrogen [ 30 , 90 ], and temperature alterations [ 26 ]. Importantly, the mechanisms of SBSN post-transcriptional regulation, as observed in therapy-resistant cancer cells [ 19 ], need to be elucidated.…”