Role of Claudin-2 in Inflammatory Diseases and Colon Cancer

Claudin-2 在炎症性疾病和结肠癌中的作用

• 批准号: 8187549
• 负责人: Amar B Singh
• 金额: $ 39万
• 依托单位: VANDERBILT UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-08-03 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8187549
• 关键词: Adoptive Transfer; Animal Model; Apoptosis; Architecture; Biology; Caco-2 Cells; Cellular biology; Characteristics; Chronic; Citrobacter rodentium; Clinical; Colitis; Colon; Colon Carcinoma; Crohn' s disease; Data; Disease; Engineering; Epithelial; Epithelial Cell Proliferation; Epithelial Cells; Epithelium; Event; Experimental Models; Family; Gene Expression; Homeostasis; Immigration; Immune; Immune response; Inflammation; Inflammatory; Inflammatory Bowel Diseases; Interleukin-1; Length; Malignant Neoplasms; Mediating; Microarray Analysis; Modeling; Molecular; Mucositis; Mus; Natural regeneration; Outcome; Pathogenesis; Pathway interactions; Patients; Permeability; Play; Protein Family; Proteins; Publishing; Regulation; Resistance; Risk; Role; Sampling; Severity of illness; Signal Transduction; Sodium Dextran Sulfate; T-Lymphocyte; TNF gene; Testing; Therapeutic Intervention; Tight Junctions; Tissues; Transgenic Mice; Ulcerative Colitis; Undifferentiated; Wild Type Mouse; base; cell motility; claudin 3; clinically relevant; colitis associated cancer; cytokine; drinking water; insight; large bowel Crohn' s disease; migration; novel; overexpression; repaired; villin

DESCRIPTION (provided by applicant): Increased mucosal permeability is a key characteristic of the inflammatory bowel disease (IBD). The claudin family of proteins constitutes the tight junctions (TJs), which are the sole determinants of the paracellular permeability in an intact epithelium. Importantly, a common finding from the analysis of the IBD (Crohn's and Ulcerative Colitis) patient samples and related animal models is that claudin-2 expression is highly upregulated in the IBD. In the claudin family, Claudin-2 is unique as its expression correlates with the epithelial leakiness. However, it is also noteworthy that the colonic claudin-2 is expressed among the undifferentiated colonocytes at the crypt base, the proliferative zone. Furthermore, outcome from our preliminary studies and recently published studies from other labs suggest potential correlation of claudin-2 expression with the colonic epithelial cell proliferation and/or migration. It is further noteworthy that claudin-2 is a target of the Wnt/¿-catenin signaling. However, role of claudin-2 in the pathogenesis of IBD is not known. To investigate, we generated Villin-claudin-2 transgenic (Cl-2Tg) mice that overexpress claudin-2 in the colon, a condition similar to the IBD. Our studies using these mice have provided novel outcomes: 1) Colonic epithelial permeability in Cl-2Tg mice is significantly increased compared to the WT littermates (p<0.05); 2) the colon and crypt lengths in Cl-2Tg mice are significantly increased compared to the wild type (WT) littermates (p<0.001 for both); and 3) Cl-2Tg mice are significantly protected from experimental-colitis [induced using dextran sodium sulfate (DSS, 4% w/v in drinking water)] compared to WT littermates (p<0.001). Our further data show sharp decreases in the DSS-induced expressions of proinflammatory cytokines including IL-1a, IL- 1¿, TNF-a in Cl-2Tg mice compared to the WT littermates. On the other hand, gene expressions related with proliferation were upregulated in the DSS-treated Cl-2Tg mice compared to the DSS-treated WT littermates. Taken together, we postulate that claudin-2 plays an important role in the regulation of colonic homeostasis. We further hypothesize that immune adaptation/tolerance due to the constitutive increase in the mucosal permeability and/or modulations of the colonic epithelial cell proliferation/apoptosis or combination of both underlie the protection from DSS-colitis in Cl-2Tg mice. To test our hypothesis, we have proposed following specific aims: 1) To determine whether claudin-2 TG mice are protected against mucosal inflammation and disease; 2) To determine the role of claudin-2 in colitis-associated regeneration, repair and colitis-associated cancer; and 3) To determine the cellular and molecular mechanism/s underlying protection from colitis in claudin-2 TG mice. We anticipate that our studies will provide valuable and clinically relevant information that will have direct impact upon the understanding of the regulation of IBD pathogenesis and its progression to cancer, and will create potential new opportunities for therapeutic interventions. PUBLIC HEALTH RELEVANCE: We will investigate the role of mucosal permeability in colonic inflammation using mice engineered to over- express claudin-2, a tight junction integral protein. We will further determine the role of claudin-2 in the regulation of colonic homeostasis, epithelial cell proliferation and a causal role in the IBD-associated cancer.

描述（由申请方提供）：粘膜通透性增加是炎症性肠病（IBD）的关键特征。 紧密连接蛋白家族的蛋白质构成了紧密连接（TJ），这是在完整的上皮细胞的细胞旁通透性的唯一决定因素。 重要的是，来自IBD（克罗恩病和溃疡性结肠炎）患者样品和相关动物模型的分析的共同发现是在IBD中紧密连接蛋白-2表达高度上调。 在claudin家族中，Claudin-2是独特的，因为其表达与上皮渗漏相关。 然而，还值得注意的是，结肠claudin-2在隐窝基部（增殖区）的未分化的结肠细胞中表达。 此外，我们的初步研究和最近发表的其他实验室的研究结果表明，claudin-2表达与结肠上皮细胞增殖和/或迁移的潜在相关性。 进一步值得注意的是，密蛋白-2是Wnt/β-连环蛋白信号传导的靶标。 然而，claudin-2在IBD发病机制中的作用尚不清楚。 为了研究，我们产生了在结肠中过表达紧密连接蛋白-2的Villin-claudin-2转基因（Cl-2 Tg）小鼠，这是一种类似于IBD的病症。 我们使用这些小鼠的研究提供了新的结果：1）与WT同窝小鼠相比，Cl-2 Tg小鼠的结肠上皮通透性显著增加（p<0.05）; 2）与野生型（WT）同窝小鼠相比，Cl-2 Tg小鼠的结肠和隐窝长度显著增加（两者均为p<0.001）;和3）与WT同窝出生的小鼠相比，Cl-2 Tg小鼠被显著保护免于实验性结肠炎[使用葡聚糖硫酸钠（DSS，4%w/v，在饮用水中）诱导]（p<0.001）。 我们进一步的数据显示，与WT同窝小鼠相比，在Cl-2 Tg小鼠中DSS诱导的促炎细胞因子（包括IL-1 a、IL- 1？、TNF-α）的表达急剧下降。 另一方面，与DSS处理的WT同窝小鼠相比，DSS处理的Cl-2 Tg小鼠中与增殖相关的基因表达上调。 综上所述，我们推测claudin-2在调节结肠稳态中起着重要作用。 我们进一步假设，由于粘膜渗透性的组成性增加和/或结肠上皮细胞增殖/凋亡的调节或两者的组合导致的免疫适应/耐受是Cl-2 Tg小鼠中DSS结肠炎保护的基础。 为了验证我们的假设，我们提出了以下具体目标：1）确定claudin-2 TG小鼠是否被保护免受粘膜炎症和疾病; 2）确定claudin-2在结肠炎相关再生、修复和结肠炎相关癌症中的作用;和3）确定claudin-2 TG小鼠中保护免受结肠炎的细胞和分子机制。 我们预计，我们的研究将提供有价值的临床相关信息，这些信息将直接影响对IBD发病机制及其向癌症进展的调控的理解，并将为治疗干预创造潜在的新机会。 公共卫生相关性：我们将使用过表达紧密连接蛋白2（一种紧密连接整合蛋白）的小鼠研究粘膜通透性在结肠炎症中的作用。 我们将进一步确定密蛋白-2在调节结肠稳态、上皮细胞增殖中的作用以及在IBD相关癌症中的因果作用。