Fig. 6: Dietary LCFAs promote the palmitoylation cycle of STAT3 in colitis.

A The levels of palmitoylated STAT3 were assessed using the acyl–biotin exchange (ABE) method in LPS-BSA and LPS-PA-treated cells. B IHC staining of APT2 in colonic tissues of ND+water, HPAD+water, ND + DSS, and HPAD + DSS mice from the experiment shown in Fig. 2A. C Cells were pre-treated with 2-BP (50 μM) or DMSO for 24 h, followed by stimulation with LPS-PA for 24 h. The levels of palmitoylated STAT3 were measured using the ABE method. D Cells were pre-treated with ML349 (20 μM) or DMSO for 24 h, followed by stimulation with LPS-PA for 24 h. The levels of palmitoylated STAT3 were measured using the ABE method. NCM460 cells were pre-treated with 2-BP (50 μM) [24], ML349 (20 μM) [14] or DMSO (control) for 24 h, followed by stimulation with LPS-PA for 24 h. E IF staining to evaluate the effect of 2-BP and ML349 on APT2 in the LPS-PA cell model. F Western blotting to assess the impact of 2-BP, ML349, and the control group on the LPS-PA cell model. G IF staining was used to assess the influence of 2-BP and ML349 on nuclear translocation of STAT3 and p-STAT3. H NCM460 cells were transfected with siDHHC7 or siNC, followed by LPS-PA intervention for 24 h. Western blotting of cells. I IF staining was used to assess the impact of siDHHC7 on nuclear translocation of STAT3 and p-STAT3. J WT Mice (n = 6) were administered with HPAD for 4 weeks, followed by 7 days of 3% DSS in drinking water. Starting from the first day of DSS administration, the mice received daily intraperitoneal injections of 2-BP (50 mg kg⁻¹) or vehicle control. K Changes in body weight. L Representative images and quantification of colon morphology and length in mice. M Representative images of colon H&E staining. Mucosal erosions, ulceration, and mucosal atrophy (red arrows), and swollen submucosa with inflammatory cell infiltration (red star). Improvement noted in the loss of crypts (blue arrows), and mitigation of inflammatory cell infiltration (blue star). N Changes in DAI. O Histological scoring of colonic tissue based on the morphology of colon sections. P Measurement of IL-6, TNF-α, and IL-1β levels in colonic tissue of mice (n = 6) using ELISA. Q IHC staining of APT2 in colonic tissue. R IHC staining of p-STAT3 in colonic tissue. S AB-PAS and IHC staining of MUC-2 in colonic tissue. T TUNEL staining of colonic tissue. U IHC staining of ZO-1 in colonic tissue. V Scanning electron microscopy images of colon tissue sections from mice, with magnified areas showing tight junctions. W Western blotting of colonic tissue. X NCM460 cells were transfected with HA-STAT3 (WT), HA-STAT3 (Y705F), and HA-STAT3 (C108S), and then stimulated with LPS-BSA or LPS-PA, and the levels of palmitoylated STAT3 were assessed using the ABE method. Y Western blotting of the cells. Data were expressed as the mean ± SD. P values were determined by 2-tailed Student t test.; ***p < 0.001, **p < 0.01, *p < 0.05.