Fig. 1: Hepatic Usp39 expression is decreased in NAFLD and NASH.

a, b Heatmap showed the expression of core U4/U6. U5 tri-snRNP components in the mouse liver models of NAFLD (n = 6) and NASH (n = 8) compared with controls using publicly available RNA-seq data (GSE165855 and (GSE154892). The quantification data was shown in Supplementary Fig. S1a, b. c Interaction network analysis of 16 U4/U6. U5 tri-snRNP components using RNA-seq data (GSE165855) and (GSE154892) visualized with Cytoscape. U4/U6. U5 complex related splicing factors were classified into U5 snRNP (orange), U4/U6 snRNP (green), and tri-snRNP (blue) according to Spliceosome DB⁴². d Correlation analysis of U4/U6. U5 splicing factors expression and NALFD activity score based on RNA-seq data of a human NAFLD cohort of 271 patients. e USP39 mRNA expression was compared between high (score ≥ 3) (n = 196) and low (score <3) (n = 75) NALFD activity score group. The bounds of the box were the upper and lower quartile with the median value in the center. The whiskers indicated the minima and maxima. The range from 10–90 percentile. f USP39 mRNA expression was compared between stage 0–1 (n = 78) and stage 2–4 (n = 192) fibrosis stage group. g, h Immunoblotting was performed to measure Usp39 protein in the livers of HFD-fed (n = 7 per group) and MCD-fed (n = 6 per group) male mice and chow-fed mice. i The USP39 protein level was measured in human healthy (n = 5) and NASH (n = 4) livers. j Immunohistochemical (IHC) staining of Usp39 in the liver sections of MCD-fed and HFD-fed male mice compared to those of the chow-fed mice (n = 12 per group). Scale bars, 50 µm. IHC image were quantified by pathologists. Resultes were shown in Fig. S1i. All immunoblotting band intensities were quantified by Image J. The p-value was obtained by Pearson R Correlation (d) and others performed unpaired two-sided Student’s t-test, and the results are presented as the mean ± S.D. CD, control diet. MW, molecular weight. Source data are provided as a Source data file.