microRNAs targeting Kit inhibit the development and maintenance of ICC

描述（由申请人提供）：Cajal间质细胞（ICC）是产生自发电慢波的起搏器细胞，并介导胃肠道运动神经元的输入。ICC网络的缺失或缺陷与胃肠道运动障碍直接相关。最近的研究表明，ICC在糖尿病性胃肠病（DGEP）的发展中起重要作用。dgp患者表现出ICC网络的缺失或缺陷，可能导致胃肠道运动障碍。ICC表达受体酪氨酸激酶KIT，是干细胞因子的受体。KIT信号是胃肠道ICC正常发育和维持所必需的。因此，dgp中ICC的缺失可能是KIT表达减少的结果。最近的研究表明Kit的表达受microRNAs （miRNAs）的调控。因此，我们的中心假设是靶向Kit的miRNAs抑制了dgp中ICC的发展和维持。为了解决这一假设，我们提出了以下具体目标：1)ICC中microRNAome的表征，2)鉴定DGEP发展过程中microrna的变化，3)miRNAs靶向Kit抑制ICC的生长和维持。为了达到具体目的，我们将利用Kit+/copGFP和2型糖尿病Kit+/copGFP两种动物模型；我们最近培育的Lepob/ob突变小鼠。这两种小鼠都以kit特异性的方式表达一种亮绿色荧光蛋白copGFP，这为研究ICC表型的功能和遗传调控提供了一个强大的新模型。完成该项目的具体目标将提供有关ICC特异性表达的mirna的信息，以及该调节分子体如何在主要胃肠道运动障碍中发生改变。我们的初步数据表明，ICC靶试剂盒中的许多mirna。本研究将描述一种涉及抑制KIT表达的mirna的新分子机制。这是一个令人兴奋的机会，了解KIT在ICC中的表达是如何被调节的，以及在dgp的发展过程中ICC是如何丢失的。鉴定抑制KIT表达的miRNA可能有助于开发一种治疗性反义miRNA药物，这种药物可能有助于阻断或逆转dgp和其他胃肠道运动和功能障碍中ICC丢失的受损ICC网络。

DESCRIPTION (provided by applicant): Interstitial cells of Cajal (ICC) are pacemaker cells that generate spontaneous electrical slow waves, and mediate inputs from motor neurons in the gastrointestinal (GI) tract. Loss or defects in ICC networks are directly linked to GI motility disorders. Recent studies have demonstrated that ICC plays an important role in the development of diabetic gastroenteropathy (DGEP). Patients with DGEP show loss or defects in ICC networks that may lead to GI motility disorders. ICC express the receptor tyrosine kinase, KIT, which is the receptor for stem cell factor. KIT signaling is required for the normal development and maintenance of ICC in the GI tract. Therefore, it is possible that loss of ICC in DGEP may be a result of reduced expression of KIT. Recent studies show that expression of Kit is regulated by microRNAs (miRNAs). Thus, our central hypothesis is that miRNAs targeting Kit inhibit the development and maintenance of ICC in DGEP. To address the hypothesis, we propose the following specific aims: 1) Characterization of microRNAome in ICC, 2) Identification of changes in microRNAs during the development of DGEP, and 3) Suppression of the growth and maintenance of ICC by miRNAs targeting Kit. To achieve the specific aims, we will utilize two animal models Kit+/copGFP and type 2 diabetic Kit+/copGFP;Lepob/ob mutant mice that we have recently generated . Both mice express a bright green fluorescent protein copGFP in a Kit-specific manner, which offers a powerful new model to study the function and genetic regulation of ICC phenotypes. Completion of the specific aims of this project will provide information about the miRNAs expressed specifically by ICC and how this body of regulatory molecules is altered in a major GI motor disorder. Our preliminary data suggest that many of the miRNAs in ICC target Kit. This study will describe a novel molecular mechanism involving miRNAs that inhibit KIT expression. This is an exciting opportunity to understand how KIT expression in ICC is regulated and how ICC are lost during the development of DGEP. Identification of the miRNAs inhibiting KIT expression may aid in the development of a therapeutic antisense miRNA drug that might be useful in blocking or reversing damaged ICC networks in DGEP and other GI motility and functional disorders in which loss of ICC occurs. PUBLIC HEALTH RELEVANCE: Loss of interstitial cells of Cajal (ICC) is directly linked to diabetic gastroenteropathy (DGEP), but the molecular mechanism underlying the ICC disruption is elusive. The present study seeks to uncover a novel mechanism involving microRNAs that lead to the loss of ICC during the development of DGEP.