Fig. 7: RNASE4 is a potential IBD diagnostic biomarker and therapeutic target.

a Quantitative mRNA expression of RNASE4 in colon samples from healthy participants (Ctrl, n = 25) and patients with IBD (n = 73), including ulcerative colitis (n = 27) and Crohn’s disease (n = 46). Expression values were normalized to β-actin. b Quantitative mRNA expression of RNASE4 in normal and inflamed colon samples from patients with IBD (n = 40). c, d Representative immunoblotting pictures (c) and quantitative results (d) of RNASE4 protein in normal and inflamed colonic tissues from patients with IBD (n = 20). e, f RNASE4 concentration (e) and relative abundance of Parasutterella (f) in stool samples from healthy participants (Ctrl, n = 45) and patients with IBD (n = 64), including UC (n = 15) and CD (n = 49). g Correlation between RNASE4 level and the abundance of Parasutterella in stool samples. h Scheme of oral RNASE4 treatment in Rnase4^−/− mice to analyze its preventive potential. i, j Body weight loss (i) and colon length (j) of WT, Rnase4^−/−, and Rnase4^−/− supplemented with the recombinant RNASE4 protein (Rnase4^−/−+RNASE4) mice during DSS-induced colitis (n = 6). k Relative abundance of Parasutterella in stool samples from WT, Rnase4^−/−, and Rnase4^−/− + RNASE4 mice (n = 6). Data are presented as mean ± SEM for (a, e, f, i, j and k); * p < 0.05; ** p < 0.01; ** p < 0.001 by two-tailed paired Student’s t-test (b and d), and two-tailed unpaired Student’s t-test (a, e, f, i, j and k). The correlation was assessed by simple linear regression analysis (g).