A174 A NOVEL MECHANISM OF CROHN’S DISEASE SEVERITY IN WOMEN: EVALUATING THE IMPACT OF AN ESTROGEN-FARNESOID X RECEPTOR INTERACTION ON INTESTINAL BARRIER FUNCTION
Bibliographic record
Abstract
Abstract Background Crohn’s disease (CD) is associated with deficits in intestinal barrier function. Activation of bile acid-sensing nuclear receptor Farnesoid X receptor (NR1H4, FXR) is associated with protective effects against reduced intestinal barrier function; namely through promoting tight junction complex genes (TJCGs) and reducing expression of inflammatory cytokines. The FXR -1G>T variant is associated with decreased FXR activation and increased risk of, and early progression to, CD-related surgery in females only. It is hypothesized an estrogen-FXR interaction is mediating this effect. Purpose We aimed to assess the combined effect of estrogen and FXR genetic variation on intestinal barrier function using a cell-based model and its impact in a clinical cohort. Method Caco-2 cells were characterized for expression of TJCGs (zonula occludens-1, occludin, junctional adhesion molecule A, and claudin-1 and claudin-2), FXR, and nuclear estrogen receptors (ERα, ERβ) by qPCR. The influence of FXR activation on TJCGs was characterized by incubation of Caco-2 cells with chenodeoxycholic acid (CDCA). FXR-knockout stable Caco-2 line was developed using CRISPR-Cas9 methods and verified by qPCR and genotyping. The effect of estradiol on expression of TJCGs in FXR-knockout and wildtype Caco-2 cell monolayers was compared by qPCR. Future experiments include comparison of FXR-knockout and wildtype monolayer permeability with estrogen exposure by transwell permeability assay. The effect of FXR genotype and exogenous estrogen CD severity (surgery, hospitalization, fistulizing disease) was evaluated in our female cohort by multivariate analysis. Result(s) Increased expression of TJCGs was seen in native Caco-2 monolayers incubated with CDCA. FXR-knockout cell line was then successfully created and confirmed. FXR-knockout cells showed decreased expression of TJCGs with the exception of zonula occludens-1. Estradiol exposure resulted in a dose-dependent decline in TJCGs expression in the wildtype Caco-2 cell line, however this effect was lost in the FXR-knockout cell line. Preliminary analysis of patient cohort data (n=359) showed exogenous estrogen was associated with lower surgery risk (OR = 0.603, 95% CI= 0.373–0.964, p < 0.05; Fischer’s exact test) and trended towards decreasing fistulizing disease risk in a multiple logistic regression model which included FXR genotype. The association of FXR genotype with increased surgery risk was also confirmed in this logistic regression model. Conclusion(s) Herein, we show that FXR activity affects expression of TJCGs, and this effect is attenuated by estrogen interactions. Our patient cohort preliminary analysis confirmed an increased CD severity risk associated with FXR genotype and demonstrated a trend of decreasing CD severity with exogenous estrogen exposure. Further studies will assess the mechanisms by which FXR and estrogen interact to influence intestinal permeability. Please acknowledge all funding agencies by checking the applicable boxes below Other Please indicate your source of funding; Department of Medicine, Western University Disclosure of Interest D. Taylor: None Declared, L. Donovan: None Declared, J. Choi: None Declared, R. Kim: None Declared, U. Schwarz: None Declared, A. Wilson Consultant of: Consulting fees from Fresenius Kabi, Speakers bureau of: Speaking fees from Takeda and Pfizer
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.003 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".