Identification and Verification of B4GALNT2 as an Epigenetic Marker in Ulcerative Colitis

Ulcerative colitis (UC) represents an inflammatory bowel disease characterized with a multifaceted pathogenesis, which may be attributed to influence by genetic factors. This study aimed to identify and validate novel markers associated with UC, with a specific focus on their regulation through DNA methylation.

Gene expression and DNA methylation profiling of intestinal mucosal tissues from UC and healthy controls was retrieved from the GEO repository. Differentially expressed and methylated genes were examined in UC. Subsequently, overlapped analyses were performed to identify highly expressed and hypomethylated genes, as well as lowly expressed and hypermethylated genes. Functional annotation, transcription factor-mRNA network analysis, and protein-protein interaction (PPI) network analysis were conducted for above genes. Dextran sodium sulfate (DSS)-induced LOVO and Caco-2 cells were established to stimulate UC injury. The expression and methylation of B4GALNT2 was verified by real-time quantitative polymerase chain reaction and methylation-specific PCR. Cell Counting Kit-8, flow cytometry, Western blot, and enzyme-linked immunosorbent assay were used to measure cell survival, apoptosis, and cytokine levels after B4GALNT2 overexpression.

Our study screened 1 downregulated and hypermethylated gene (B4GALNT2) and 114 upregulated and hypomethylated genes in UC. They were markedly associated with immune response. Totally, 10 potential transcription factors were predicted. The PPI network revealed their complex interactions. B4GALNT2 was confirmed to be downregulated and hypermethylated in DSS-induced intestinal epithelial cells and in DSS-induced UC mouse model. B4GALNT2 overexpression enhanced cell viability and weakened apoptosis and cytokine production and release of DSS-induced intestinal epithelial cells.

Collectively, this study integrally analyzed DNA methylation and gene expression in UC as well as identified and verified B4GALNT2 as a key epigenetic marker.