Thymosin β4 released by mast cells under stress conditions impairs intestinal epithelial barrier via IL22RA1/JAK1/STAT3 signaling in irritable bowel syndrome

Figure 2 Thymosin β4 is a key factor in the disruption of the intestinal barrier by mucus in irritable bowel syndrome. A and B: Caco2 cells were treated with irritable bowel syndrome mucus, the cell viability was detected by cell counting kit-8 assay (A), and the TEER value was analyzed after mucus treatment for 30 minutes at 1 μg/mL (B). Bar, SD, ^aP < 0.001 vs the Mucus23 group at 0 minute, ^bP < 0.001 vs the Mucus23 group at 0 minute, ^cP < 0.01 vs the Mucus21 group at 0 minute; C and D: Intestinal barrier permeability was assessed by (C) TEER and (D) FD4 assays between mucus and thymosin β4 antibody (anti-Tβ4) groups. Anti-IgG was applied as a control. (n = 3) Bar, SD, ^dP < 0.001 vs the anti-IgG group, ^eP < 0.001 vs the Mucus group; E-G: Respective immunofluorescence images of (E) zonulin 1 and (F) Occludin, and (G) western blots in Caco2 cells treated with mucus, mucus + anti-Tβ4, anti-Tβ4 or anti-IgG. Scale bar, 50 μm. The data are presented from at least three independent experiments run in triplicate. Bar, SD, ^dP < 0.001 vs the anti-IgG group, ^fP < 0.01 vs the anti-IgG group, ^gP < 0.01 vs the Mucus group, ^hP < 0.05 vs the Mucus group. ZO-1: Zonulin 1; Tβ4: Thymosin β4; IBS: Irritable bowel syndrome.