Fig 2: Colonic FPRL1 expression is present in IBD patients. (A) Colonic FPRL1 mRNA expression in normal, UC, and CD patients. (B) Immunohistochemistry of FPRL1 protein. The FPRL1 expression is located at the mucosal lining and the submucosal region as indicated by arrows. Magnification 200X. (C) Scatter plot shows that there was no correlation between colonic FPRL1 mRNA expression and clinical disease activity in UC patients. (D) Scatter plot shows that there was no correlation between colonic FPRL1 mRNA expression and clinical disease activity in CD patients. Data consist of colonic tissues from 40 normal, 50 UC, and 44 CD patients of cohort 1.

Fig 3: Subcutaneous CSA13 administration suppressed colonic fibrosis via FPRL1. (A) Experimental plan of TNBS colitis. (B) Changes in body weight. TNBS treatment significantly reduced body weight. (C) H&E staining. (D) Masson Trichrome staining. Blue color indicates deposition of collagen. (E) Histology score. (F) Fibrosis score. (G) Alpha diversity (richness as measured by Chao1) is shown for fecal samples of the mice (3–4 mice per group). (H) Principal coordinates plot of unweighted UniFrac for all mice. The significance of differences in microbial composition (beta diversity) across groups was determined using a permutational method (PERMANOVA) and the p-value is shown in the plot. (I) Colonic mRNA expression. Each group consists of 6 mice in 2 separate experiments.

Fig 4: CSA13 did not affect cell viability and cell migration of fibroblasts. (A) Human CCD18Co fibroblasts were transiently transfected with control or FPRL1 siRNA overnight, followed by CSA13 for 24 hours. Each PCR array (Human Fibrosis PAHS120ZE-4, Qiagen, CA) detects 84 genes. Only CSA13-dependent genes are shown here. (B) The CCD-18Co fibroblasts were treated with CSA13 for 24 hours. The cell viability was determined by MTS assay at 490 nm. (C) The 3T3 fibroblasts were treated with CSA13 for 72 hours. The scratch gaps were recorded at 100X magnification. The results are representative of 3 experiments.

Fig 5: Kaempferol restored epithelial‐fibroblast homeostasis by suppressing fibroblast activation via ANXA1/FPR2 signaling upregulation. (A) Co‐IP analysis of specific binding between ANXA1 and FPR family members (FPR1, FPR2, and FPR3). Input: Lysates from fibroblasts co‐cultured with the indicated epithelial cell groups, probed for ANXA1, FPR1, FPR2, and FPR3. IP‐ANXA1: Immunoprecipitates from fibroblast lysates (co‐cultured with the indicated epithelial cell groups) using ANXA1 antibody, probed for FPR1, FPR2, and FPR3. (B) IF staining of ANXA1 and FPR2 expressions in fibroblasts (scale bar = 25 μm). (C) Western blot analysis of fibroblast activation markers (FAP, VIM, α‐SMA, and MMP1). (D) IF staining of α‐SMA expression in fibroblasts (scale bar = 25 μm). *p < 0.05 vs. OSF, # p < 0.05 vs. OSF + Kaempferol, and p < 0.05 vs. OSF + Kaempferol+sh‐NC. (E) IF staining of ANXA1 and FPR2 expressions in fibroblasts (scale bar = 25 μm). (F) Western blot analysis of fibroblast activation markers (FAP, VIM, α‐SMA, and MMP1). (G) IF staining of α‐SMA expression in fibroblasts (scale bar = 25 μm). Data are presented as mean ± SD (n = 3). *p < 0.05 vs. sh‐N C.