IDDF2024-ABS-0164 7-Ketositosterol in ultra-processed foods aggravates colitis by gut dysbiosis induced-PDLIM3 activation

<h3>Background</h3> Diet and gut microbiota alteration are considered as the most important environmental factors triggering inflammatory bowel disease. Excessive ultra-processed foods (UPFs) consumption has been reported to be associated with the development of inflammatory bowel disease (IBD). As an important ingredient, 7-ketositosterol (KS) is mainly synthesized from high-temperature heating oils and exerts pro-inflammatory effects. It remains unknown whether KS could promote colonic inflammation and alter gut microbiota. <h3>Methods</h3> The fried and baked foods intake was collected and compared in IBD patients and healthy individuals. KS was synthesized from β-sitosterol and the impacts of KS on intestinal inflammation were evaluated in colitis mice models. Gut microbiota depletion and fecal microbiota transplantation (FMT) combined with 16s rRNA and Transcriptomic sequencing are conducted to explore the correlation between gut microbiota and genetic modulation. The protein interaction of <i>Staphylococcus_lentus</i> and PDZ and LIM Domain 3 (PDLIM3) was explored by co-immunoprecipitation and LC-MS analysis. <h3>Results</h3> The fried and baked foods intake in IBD patients was much more than that of healthy individuals, with higher exposure to KS. KS aggravated mice colitis (IDDF2024-ABS-0164 Figure 1 (a-c)). KS increased the abundance of potential pathogens such as <i>Staphylococcus</i> (<i>P</i>=0.004) and decreased the abundance of short-chain fatty acids-producing bacteria (IDDF2024-ABS-0164 Figure 1 (d)). Transcriptome data and Western blotting showed KS increased the expression of PDLIM3 (p=0.004), and the expression tendency of p-p38 and p-p65 was consistent with PDLIM3 (IDDF2024-ABS-0164 Figure 2 (a-b)). In addition, KS did not exacerbate DSS-induced colitis after antibiotic cocktail treatment, and PDLIM3 expression decreased in parallel (IDDF2024-ABS-0164 Figure 2 (c)). The gut microbiota from KS also aggravated DSS-induced colitis in antibiotic-treated mice (IDDF2024-ABS-0164 Figure 2 (d)). Oral administration of <i>Staphylococcus_lentus</i> (SL) aggravated colitis and SL-derived Lysin motif peptidoglycan-binding domain-containing protein could interact with PDLIM3 (IDDF2024-ABS-0164 Figure 2 (e)). Furthermore, tubuloside B, selected by high-throughput screening, blocked the binding interfaces and ameliorated SL-induced colitis. <h3>Conclusions</h3> 7-ketositosterol in UPFs could aggravate colitis by modulation of gut microbiota. Gut microbiota, especially Lysin motif peptidoglycan-binding domain-containing protein from <i>Staphylococcus lentus</i>, could interact with PDLIM3 and activate p38MAPK/NF-κB signaling pathway.