A86 NON-PREBIOTIC EFFECTS OF RHAMNOGALACTURONAN ON INTESTINAL EPITHELIAL BARRIER FUNCTION AND WOUND HEALING
Bibliographic record
Abstract
Dietary fibre comprises a complex group of polysaccharides that are indigestible but are fermented by gut microbiota, promoting beneficial effects to intestinal mucosa indirectly. However, studies have shown that polysaccharides also have direct effects on intestinal epithelial barrier function. Recently, we found that rhamnogalacturonan (RGal), a polysaccharide isolated from Acmella oleracea, protected mice against DSS colitis. However, the underlying mechanism of action of RGal remains unclear. We aimed to verify whether RGal directly enhances intestinal epithelial barrier function and promotes wound healing to maintain tissue health. Monolayers of human colonic epithelial Caco-2 cells were mounted in Ussing chambers and treated apically with RGal (10–1000 µg/ml). Transepithelial electrical resistance (TER) and FITC-dextran flux were measured. In a calcium-switch assay, the epithelial monolayers were temporarily exposed to zero calcium conditions (calcium-free buffer containing the calcium chelator, EGTA) to disassemble tight junctions. RGal (10–1000 µg/ml) was added during calcium-free conditions and its effect on barrier recovery during the return to Ca-containing buffer was assessed. FITC-dextran permeability was also evaluated in Caco-2 cells stimulated with IFNg plus TNF-a (25 ng/ml, basolateral) and co- or post-treated with RGal (1000 µg/ml, apical) for 48 or 24 h, respectively. Immunofluorescence staining was performed for evaluation of tight junction proteins, occludin and ZO-1. Finally, to evaluate wound healing, scratch wounds were performed on cell monolayers treated with RGal (10–1000 µg/ml) at 0 and 24 h. Wound healing was assessed over 48 h using the IncuCyte live cell imaging system. Apical treatment of cells with RGal (1000 µg/ml) significantly increased TER and reduced FITC-dextran flux compared to control. Additionally, apical addition of RGal accelerated tight junction reassembly in the calcium switch assay. Exposure to cytokines enhanced FITC-dextran flux and disrupted tight junction protein localization. Co- and post-treatment of cells with RGal (1000 µg/ml) reversed this effect on FITC-dextran flux by 13 and 16% at 60 min, respectively, and preserved the occludin and ZO-1 distribution. In the wound healing assay, RGal at concentration of 1000 µg/ml enhanced wound healing by 28% at 48 h compared to control group, under 10% serum but not serum free conditions. We demonstrated that RGal increased barrier function through acceleration of tight junction assembly, prevented cytokine-induced barrier dysfunction, and was able to increase wound healing in vitro. Elucidation of RGal mechanisms of action could lead to new approaches to the treatment of inflammatory diseases of the gut that are characterized by compromised epithelial barrier function. CIHR
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| 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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".