SETD2 Deficiency Promotes Inflammatory Bowel Disease via Oxidative Stress and FasL-Mediated Apoptosis

Author(s): Yueduo Wang, Shenghai Shen, Haorui Zhu

Background: SET-domain-containing 2 (SETD2) is known as the only trimethyltransferase for regulating histone H3 lysine 36 (H3K36) methylation, being involved in the generation and development of many diseases. Although SETD2 has been found to modulate oxidative stress in the intestinal epithelial tissue of inflammatory bowel disease (IBD) samples, the specific functions of SETD2 in IBD development are yet to be fully understood.

Methods: Setd2-flox (Setd2F/F) mice were crossed with Villin-cre transgenic (Setd2Vli-Cre) mice to generate intestinal epithelium-specific deletion of Setd2 (Setd2Vli-KO) mice, followed by genotyping with PCR. RNA-seq expression profiles were gathered from the GEO database for differential expression analysis. According to gene ontology (GO) analysis, four genes were selected as indicators for further expression validation. Total RNA from IBD-induced Setd2Vil-KO mice intestinal epithelium tissue was extracted for RT-qPCR. TUNEL assay was conducted for detecting the apoptotic signaling level, and immunofluorescence was utilized for detecting the FasL protein expression in IBD-induced Setd2Vil-KO mice intestinal epithelium tissue.

Results: Four genes (Cybb, Lpo, FasL, Tnfrsf8) related to oxidation-reduction and apoptotic process-promotion were identified as indicators. Compared with wild-type mice, down-regulation of Cybb and Lpo was detected, as well as the up-regulation of FasL and Tnfrsf8 were up-regulated in the intestinal epithelial tissue of Setd2Vli-KO mice via RT-qPCR validation. Furthermore, TUNEL assay and immunofluorescence revealed significant enhancement in apoptotic signaling and FasL protein expression.

Conclusions: SETD2 deficiency promotes FasL-mediated apoptosis and oxidative stress in IBD intestinal epithelium tissue and hence plays an essential role in IBD pathogenesis. Altogether, our research provided new insights into IBD development.