title: Sox9 transcriptionally regulates Wnt signaling in intestinal epithelial stem cells in hypomethylated crypts in the diabetic state.
abstract: Distinctive structures called crypts harbor intestinal epithelial stem cells (IESCs) which generate progenitor and terminally differentiated cells in the intestinal epithelium. Mammalian IESCs and their daughter cells require the participation of DNA methylation and the transcription factor Sox9 for proliferation and differentiation. However, the association between Sox9 and DNA methylation in this process remains elusive.
  
  
  
  The DNA methylation of small intestinal epithelial crypts in db/db mice was detected via combining methylated DNA immunoprecipitation with microarray hybridization. DNA methylation of Sox9 promoter in crypts and IESCs was validated using bisulfite sequence analysis. The target sequence of the transcription factor Sox9 in IESCs was investigated via chromatin immunoprecipitation (ChIP) combined with deep sequencing (ChIP-seq).
  
  
  
  Increased Sox9 expression is accompanied by the loss of methylation in its promoter in IESCs. Sox9 targets the enhancers of the Wnt signaling pathway-related genes. Sox9 predominantly acts as a transcriptional activator at proximal enhancers of Wnt4, Tab2, Sox4, and Fzd8, but also functions as a potential transcriptional inhibitor at a distant enhancer of Cdk1. Lack of Sox9 transcriptional activation in specific repressors of the Wnt signaling pathway leads to the loss of intrinsic inhibitory action and ultimately produces overactivation of this pathway in db/db mice.
  
  
  
  Our study sheds light on the connections among DNA methylation, transcription factor modulation, and Wnt signaling in IESCs in the diabetic state. Hypomethylation in the Sox9 promoter is correlated to increased Sox9 expression in db/db IESCs. Although there is increased expression of Sox9 in db/db IESCs, the loss of Sox9 transcriptional activation in specific repressors of the Wnt signaling pathway might result in abnormalities in this pathway.
authors.affiliation: Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China.|Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China.
authors.forename: Can-Ze
authors.initials: CZ
authors.lastname: Huang
authors.affiliation: Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China.
authors.forename: Ji-Hao
authors.initials: JH
authors.lastname: Xu
authors.affiliation: Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China.
authors.forename: Wa
authors.initials: W
authors.lastname: Zhong
authors.affiliation: Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China.
authors.forename: Zhong-Sheng
authors.initials: ZS
authors.lastname: Xia
authors.affiliation: Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China.
authors.forename: Si-Yi
authors.initials: SY
authors.lastname: Wang
authors.affiliation: Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China.
authors.forename: Di
authors.initials: D
authors.lastname: Cheng
authors.affiliation: Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China.
authors.forename: Jie-Yao
authors.initials: JY
authors.lastname: Li
authors.affiliation: Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China.
authors.forename: Ting-Feng
authors.initials: TF
authors.lastname: Wu
authors.affiliation: Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China. qikui_chen@yeah.net.
authors.forename: Qi-Kui
authors.initials: QK
authors.lastname: Chen
authors.affiliation: Department of Gastroenterology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China. yutaosysmh@hotmail.com.|Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, 107 Yan Jiang Xi Road, Guangzhou, Guangdong, 510120, China. yutaosysmh@hotmail.com.
authors.forename: Tao
authors.initials: T
authors.lastname: Yu
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D019175:DNA Methylation / Q000235:genetics*; D003920:Diabetes Mellitus / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D018507:Gene Expression Regulation, Developmental; D059014:High-Throughput Nucleotide Sequencing; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism / Q000473:pathology; D051379:Mice; D016688:Mice, Inbred NOD; D011401:Promoter Regions, Genetic; D055758:SOX9 Transcription Factor / Q000235:genetics*; D033581:Stem Cell Transplantation; D013234:Stem Cells / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics; D060449:Wnt Signaling Pathway / Q000235:genetics
chemical_list: D055758:SOX9 Transcription Factor; C527933:Sox9 protein, mouse
keywords: DNA methylation; Diabetes mellitus; Intestinal epithelium stem cells; Sox9; Wnt signaling