Colon Cell Differentiation: NAB and MUC2 Gene Expression

结肠细胞分化：NAB 和 MUC2 基因表达

• 批准号: 7031044
• 负责人: ANNA VELCICH
• 金额: $ 23.53万
• 依托单位: MONTEFIORE MEDICAL CENTER (BRONX, NY)
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-15 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7031044
• 关键词: DNA replication origin; RNA interference; butyrates; cell differentiation; chromatin immunoprecipitation; colon; gene expression; genetic promoter element; genetic regulation; genetic transcription; in situ hybridization; intestinal mucosa; microarray technology; mucins; transcription factor

DESCRIPTION (provided by applicant): The short chain fatty acid butyrate (NaB), present in high concentrations in the colonic lumen principally from the fermentation of dietary fiber, plays a physiological role in colonic homeostasis. This involves maintaining an equilibrium not only between cell proliferation in the lower section of the crypt and cell loss at the top of the crypt, but also a balance among the multiple cell lineages in the mucosa. However, butyrate effects are complex, in that butyrate induces differentiation in vitro, but promotes growth in vivo. This complexity is further emphasized by our findings demonstrating that NaB specifically represses that expression of the MUC2 gene, which encodes the major colonic mucin, and does so by inhibiting HDAC activity (Oncogene, in press). It is our hypothesis that the intestine has developed specific mechanisms to respond to natural compounds, such as NaB, present in the lumen to modulate cell differentiation as a function of cell position along the crypt axis. Alterations in this balance may increase the probability of tumor formation. Utilizing cell systems that recapitulate the goblet and ion transporter phenotypes, and molecular reagents developed in the lab, we will define the molecular determinants in cell lineage specific differentiation that can be regulated by NaB by determining: 1. Whether there are NaB responsive elements in the promoter of the human and mouse MUC2 genes. 2. Whether HDAC activity can counteract NaB mediated repression of MUC2 3. Whether there is modulation of SP1/SP3 activity, which we demonstrated is important for MUC2 regulation. 4. Whether post-translational modifications of SP1/SP3 may bring about loss of transcriptional activity. This will be done in vitro using standard immunological and molecular biology techniques. We will expand these studies in vivo, and determine, by CHIP analysis, if the chromatin structure of the gene is important for MUC2 expression. In addition, we will determine the dynamic occupancy of SP1/SP3 at functionally relevant sites, and the transcription factors and co-factors that may participate in the formation of multiprotein complexes upon interaction with SP1 and SP3 as a function of MUC2 repression. 5. Finally, we will extend our use of microarray technology to determine how NaB perturbs profiles of gene expression that define lineage specific differentiation (Velcich et al., submitted).

描述（由申请人提供）：短链脂肪酸丁酸盐（NaB）主要通过膳食纤维的发酵高浓度存在于结肠腔中，在结肠内稳态中起生理作用。这不仅需要维持隐窝下部的细胞增殖和隐窝顶部的细胞损失之间的平衡，还需要维持粘膜中多个细胞系之间的平衡。然而，丁酸盐的作用是复杂的，因为丁酸盐在体外诱导分化，但在体内促进生长。我们的研究结果进一步强调了这种复杂性，表明NaB通过抑制HDAC活性特异性地抑制MUC2基因的表达，MUC2基因编码主要的结肠粘蛋白（Oncogene, in press）。