Fig. 4: Intestinal cells with Tm6sf2 deficiency secrete free fatty acids to induce gut microbiota dysbiosis.
a, Experimental schematic of untargeted metabolomic profiling on the culture supernatant of IECs isolated from Tm6sf2ΔIEC and Tm6sf2fl mice. Created with BioRender.com. b, PCA analysis and heat map of differential metabolites secreted by IECs from mice (n = 8 per group). c, Metabolomics targeting free fatty acids on the cultural supernatant of isolated IECs (n = 8 per group). d, Representative small intestine images of H&E staining and intestinal triglyceride of Tm6sf2ΔIEC mice fed with NC (n = 5 per group) or CD-HFD (n = 9 per group). e, Silver staining coupled with mass spectrometry analysis after pull-down assay on mouse intestinal tissues. f, Co-immunoprecipitation of TM6SF2 and FABP5 using mouse intestinal proteins. g, MST assay for direct binding between TM6SF2 and FABP5 with dissociation constant (Kd) provided. h, Representative structure of molecular docking between TM6SF2 (purple) and FABP5 (blue). i, Metabolomics targeting free fatty acids in TM6SF2 KO Caco2 cells with or without FABP5 overexpression (n = 6 per group). j, Experimental schematic and intestinal permeability by FITC-labelled dextran assay in mice supplemented with the top differential free fatty acids (n = 5 per group). k, Permeability of Caco2 cell monolayers treated with arachidic acid or arachidonic acid (n = 3 per group). l,m, Heat map of differential faecal microorganisms (l) and LPA-targeting metabolomics on portal vein serum (m) of mice treated with free fatty acids (n = 4–5 per group). Results are presented as the mean ± s.d. Experiments were repeated three times with similar results (e and f). Statistical significance was determined by two-tailed Student’s t-test (c, d, i and k) or one-way ANOVA followed by Turkey’s multiple comparison (j and m).
