Intestinal adaptation and epidermal growth factor

肠道适应和表皮生长因子

• 批准号: 6872909
• 负责人: BRAD Wayne WARNER
• 金额: $ 30.55万
• 依托单位: CINCINNATI CHILDRENS HOSP MED CTR
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6872909
• 关键词: apoptosis; biological signal transduction; cell differentiation; cell migration; cell proliferation; epidermal growth factor; gastrointestinal absorption /transport; gel mobility shift assay; genetically modified animals; growth factor receptors; immunocytochemistry; intestine surgery; laboratory mouse; laser capture microdissection; northern blottings; polymerase chain reaction; postoperative state; proliferating cell nuclear antigen; receptor binding; receptor expression; small intestines; tissue /cell culture; transcription factor; western blottings

DESCRIPTION (provided by applicant): After massive small bowel resection (SBR), the remaining intestine compensates by a critical process termed adaptation. Adaptation is largely a mitogenic signal for increased enterocyte proliferation, thus generating taller villi, and greater bowel caliber and length. While the mechanism for resection-induced enterocyte proliferation is presently unknown, we have established that epidermal growth factor receptor (EGFR) signaling is critical. Using p21waf1/cip1-null mice, we determined that proliferation was paradoxically abolished after SBR in the absence of this cyclin dependent kinase inhibitor. As an extension of these observations, we propose the global hypothesis that EGFR signaling regulates the expression of p21 to initiate enterocyte proliferation after SBR. To test this hypothesis, our aims are: 1) Delineate the effects of SBR and EGFR manipulations on intestinal p21 expression. Laser capture microdissection (LCM) microscopy wilt be employed to establish a temporal, regional, and enterocyte-specific expression of p21 mRNA and protein along the crypt-villus axis after SBR. Both in vivo and in vitro models of adaptation will be studied under conditions of EGFR stimulation and inhibition. 2) Determine the mechanism for EGFR regulation of p21. To test the hypothesis that EGFR governs p21 expression via STAT, we will elucidate STAT expression and activation after SBR in vivo and in vitro. We will then delineate p21 expression during adaptation in vitro after inhibition of STAT and in vivo in STATl-null mice. 3) Determine the mechanism for blocked postresection proliferation in p21-null mice. This aim will test the hypothesis that postresection proliferation is prevented in p21-null mice because of compensatory increased expression of p27kip1. A temporal and cell compartment profile of P27 expression will be determined in p21-null mice. The magnitude of adaptation will then be elucidated in p27-null and p21/p27 double-null mice. These studies will contribute substantially toward an enhanced understanding of critical early signaling pathways involved in the regulation of adaptation. This information is fundamental toward the future development of safe and effective clinical therapy designed to amplify this important process.

描述（由申请人提供）：大面积小肠切除术（SBR）后，剩余的肠道通过称为适应的关键过程进行补偿。适应主要是肠上皮细胞增殖增加的促有丝分裂信号，从而产生更高的绒毛，以及更大的肠口径和长度。虽然切除诱导的肠上皮细胞增殖的机制目前尚不清楚，但我们已经确定表皮生长因子受体（EGFR）信号传导是关键。使用p21 waf 1/cip 1-null小鼠，我们确定，在没有这种细胞周期蛋白依赖性激酶抑制剂的情况下，SBR后的增殖被矛盾地取消。作为这些观察结果的延伸，我们提出了一个全球性的假设，即EGFR信号调节p21的表达，启动肠上皮细胞增殖后SBR。为了验证这一假设，我们的目标是：1）描述SBR和EGFR操作对肠道p21表达的影响。激光捕获显微切割（LCM）显微镜将被用来建立一个时间，区域和肠细胞特异性表达的p21 mRNA和蛋白质沿着隐窝绒毛轴后SBR。将在EGFR刺激和抑制条件下研究体内和体外适应模型。2)确定p21的EGFR调节机制。为了验证EGFR通过STAT调控p21表达的假设，我们将阐明体内和体外SBR后STAT的表达和活化。然后，我们将描绘在STAT抑制后体外适应期间和在STAT 1缺失小鼠体内适应期间的p21表达。3)确定p21基因敲除小鼠切除后增殖受阻的机制。这一目标将测试的假设，切除后增殖的p21基因敲除小鼠，因为补偿性增加表达p27 kip 1的预防。将在p21缺失小鼠中测定P27表达的时间和细胞区室谱。然后将在p27无效和p21/p27双无效小鼠中阐明适应的幅度。这些研究将大大有助于加强对参与适应调节的关键早期信号通路的理解。这些信息对于未来开发旨在放大这一重要过程的安全有效的临床治疗至关重要。