A40 IDENTIFYING NOVEL ROLES FOR TLR2 SIGNALING IN THE INTESTINAL EPITHELIUM USING ORGANOIDS
Bibliographic record
Abstract
Abstract Background Inflammatory bowel disease (IBD) is thought to result from an imbalance between protective and damaging immune responses to the resident microbiota and other luminal antigens. Increasing evidence suggests that toll-like-receptor (TLR)-mediated innate immune dysfunction contributes to the pathogenesis of IBD. Among the receptors in the TLR family, TLR2 and its signalling pathway appears to play an important protective role in the gastrointestinal (GI) tract. Notably, our group previously discovered that Tlr2 expression by nonhematopoietic cells played an important protective role in the Citrobacter rodentium model of infectious colitis. Aims To determine if intestinal epithelial cells (IECs) control Tlr2 dependent tissue protective responses, we sought to characterize the role of Tlr2 signalling in intestinal organoids. In addition, to better define the role of Tlr2 during C. rodentium infection, we developed a novel in vitro model of C. rodentium infection using organoid-derived monolayers. Methods Organoids were derived from the colonic tissue of wild type (C57BL/6J) and Tlr2 deficient (-/-) mice and then stimulated with Tlr2 agonists, and their responses were evaluated by qPCR, ELISA, Western blot and immunostaining. In addition, 2D monolayers were grown from organoids, and infected with C. rodentium to explore whether Tlr2 signaling regulates other protective IEC functions such as barrier proteins and cell death in response to noxious stimuli. Results Stimulation of WT, but not Tlr2-/- mouse orgnaoids led to increased transcription of chemokine and cytokine genes Ccl20, Mcp-1, Cxcl1 and Tnf-α. This was accompanied by increased protein secretion through a NF-κB and p38 MAP kinase dependent mechanism. Interestingly, organoids derived from the distal colon displayed stronger Tlr2 responses than organoids from the proximal colon. During C. rodentium infection of monolayers, Tlr2 signaling had no effect on the distribution of tight junction proteins such as ZO-1 or Claudin3, however, Tlr2 did regulate levels of IEC apoptosis upon C. rodentium infection. Conclusions Our study demonstrates that colonic organoids express functional Tlr2, which upon stimulation, leads to pro-inflammatory responses as well as control over cell death. Our novel C. rodentium infection model enables us to further study the role of IEC in promoting host defense during bacterial infection. Futher work will examine how interactions with Tlr2 dependent cytokines (ie. IL-6, IL-22) impact IEC responses to C. rodentium. Funding Agencies CCC, CIHRCH.I.L.D
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 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".