Histamine modulation of biliary proliferation and damage

组胺调节胆道增殖和损伤

• 批准号: 8442621
• 负责人: Heather L Francis
• 金额: --
• 依托单位: OLIN TEAGUE VETERANS CENTER
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-10-01 至 2015-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8442621
• 关键词: Affect; Alcohols; Apoptosis; Award; Bile Acids; Bile fluid; Biliary; Carbon Tetrachloride; Cell Count; Cell Line; Cells; Cholestasis; Chronic; Data; Development; Disease; Disease Progression; Down-Regulation; Duodenum; Enzymes; Epithelial Cells; Epithelium; Event; Extrahepatic Bile Ducts; Extrahepatic Cholestasis; G-Protein-Coupled Receptors; Goals; Growth; Health; Hepatic; Hepatocyte; Histamine; Histamine Receptor; Histamine Release; Histidine; Histidine Decarboxylase; Homeostasis; Hormone Responsive; Hospitalization; Hyperplasia; In Vitro; Inflammatory; Lead; Ligation; Liver; Liver diseases; Mediating; Mission; Modeling; Modification; Molecular; Morbidity - disease rate; Neurosecretory Systems; Pathology; Patients; Primary biliary cirrhosis; Proliferating; Publishing; Regulation; Research; Risk; Role; Signal Pathway; Signal Transduction; Therapeutic Intervention; Toxin; Vascular Endothelial Cell; Veterans; autocrine; base; bile duct; biliary tract; cholangiocyte; hepatotoxin; in vivo; insight; interest; intrahepatic; liver injury; mast cell; mortality; novel; overexpression; paracrine; primary sclerosing cholangitis; programs; receptor; response; therapeutic target

DESCRIPTION (provided by applicant): Cholangiocytes are key target cells in diseases such as primary biliary cirrhosis and primary sclerosing cholangitis collectively known as cholangiopathies. Cholangiocytes are epithelial cells lining the bile ducts and are responsible for the modification and release of bile into the duodenum. These cells are hormone-responsive and behave in an autocrine fashion (secreting a number of neuroendocrine factors) regulating their own growth and/or apoptosis. During the course of cholangiopathies, cholangiocytes proliferate or are lost (ductopenia) to compensate for the changes in intrahepatic biliary mass. The overall goal of this proposal is to examine the role of biliary histidine decarboxylase (HDC, the enzyme, also expressed by cholangiocytes in the liver, regulating histamine synthesis), histamine synthesis and histamine receptor interaction on cholangiocyte proliferation and/or damage. In support of our proposed objectives, we have previously shown that: (i) histamine (HA) regulates, via its four G-protein coupled receptors (H1-H4), biliary growth/damage; and (ii) the enzyme responsible for histidine to histamine conversion, HDC, is overexpressed in cholangiocytes following extrahepatic bile duct obstruction (BDL). We have also shown that: (i) cholangiocytes express all four subtypes of histamine receptors (HRs); and (ii) H1HR and H2HR stimulate cholangiocyte growth, whereas H3HR or H4HR inhibit biliary growth during cholestasis. In addition to cholangiocytes, histamine is synthesized mainly from mast cells in response to many pathologies and inflammatory diseases. After release histamine is quickly stored or degraded. On the basis of the preliminary and published data, we propose the novel hypothesis that autocrine cholangiocyte release of histamine regulates cholangiocyte response in models of proliferation/damage via HDC and specific histamine receptors. The following specific aims are proposed: Specific aim 1: To evaluate the (i) hepatic distribution/expression of HDC in liver sections and purified liver cells including cholangiocytes, hepatocytes and vascular endothelial cells; and (ii) in vivo effects of the modulation of HDC expression on biliary growth/damage in models of a. cholangiocyte proliferation induced by extrahepatic bile duct ligation (BDL); and b. biliary damage (by apoptosis) induced by treatment with the hepatotoxin, carbon tetrachloride (CCl4). The overall goal of this aim is to demonstrate that in models of proliferation (BDL) or damage (CCl4), HDC levels are increased/decreased, respectively, and that alteration of HDC and histamine synthesis will directly affect cholangiocyte proliferative responses. Specific Aim 2 - To evaluate the specific contribution of histamine receptors during cholangiocyte proliferation/damage and the downstream signaling pathways. To achieve this, we will use pharmacological and molecular approaches to block the specific HRs and to evaluate receptor- specific effects on biliary functions in vitro. The overall goals of this aim are to demonstrate that: (i) our in vivo effects are specific to cholangiocytes; and (ii) to pinpoint the specific histamine receptor responsible for the activation of secondary signaling pathways and effects on cholangiocyte proliferation. These studies will demonstrate that HDC/histamine-mediated effects are regulated by the activation of stimulatory (H1 and H2HRs) and inhibitory (H3 and H4HRs) histamine receptors. At the completion of this project, we expect to have determined the extent and the signaling mechanisms involved through which the proliferation/damage of the biliary epithelium is regulated by the autocrine synthesis of histamine by HDC. The information gained upon the successful completion of these studies are expected to provide important insights into the factors controlling cholangiocyte proliferation/damage, which will ultimately help in the identification of important signaling pathways that can be targeted for the development of therapeutic interventions for chronic cholestatic liver diseases. The study introduces the novel concept that HDC may be an important therapeutic target for the management of biliary disorders. While down-regulation of HDC and histamine synthesis may be important in the inhibition of biliary hyperplasia, overexpression of HDC (leading to enhanced histamine release) may be key for stimulating biliary proliferation in ductopenic conditions associated with biliary damage

描述（由申请人提供）： 胆管细胞是诸如原发性胆道肝硬化和原发性硬化胆管炎等疾病中的关键靶细胞。胆管细胞是胆管内衬的上皮细胞，并负责将胆汁的修饰和释放到十二指肠。这些细胞具有激素反应性，并以自分泌方式（分泌多种神经内分泌因素）来调节其自身生长和/或凋亡。在胆管疾病的过程中，胆管细胞增殖或丢失（延性），以补偿肝内胆道质量的变化。该提案的总体目的是检查胆道组氨酸脱羧酶（HDC，酶，也以胆管细胞的形式表达，调节组胺合成），组胺合成和组胺受体受体相互作用在胆管细胞增殖和/或损伤上。为了支持我们提出的目标，我们先前已经表明：（i）组胺（HA）通过其四个G蛋白偶联受体（H1-H4），胆道生长/损害来调节； （ii）负责组胺转化为组胺转化的酶HDC在肝外胆管梗阻（BDL）后在胆管细胞中过表达。我们还表明：（i）胆管细胞表达组胺受体的所有四个亚型（HRS）； （ii）H1HR和H2HR刺激胆管细胞的生长，而H3HR或H4HR抑制胆汁淤积过程中的胆汁生长。除胆管细胞外，组胺主要是从肥大细胞中合成的，响应许多病理和炎症性疾病。释放后，组胺很快被储存或降解。根据初步和发布的数据，我们提出了一种新的假设，即组胺的自分泌细胞释放组胺可调节通过HDC和特定组胺受体的增殖/损伤模型中的胆管细胞反应。提出了以下特定目的：特定目的1：评估肝脏切片和纯化的肝细胞中HDC的（i）肝分布/表达 包括胆管细胞，肝细胞和血管内皮细胞； （ii）HDC表达调节对a的模型中胆道生长/损伤的体内影响。肝外胆管连接（BDL）诱导的胆管细胞增殖；和b。用肝毒素，四氯化碳（CCL4）治疗引起的胆道损伤（通过凋亡）。该目标的总体目标是证明在增殖模型（BDL）或损伤（CCL4）中，HDC水平分别提高/降低，并且HDC和组胺合成的改变将直接影响胆管细胞增殖反应。具体目标2-评估胆管细胞增殖/损伤和下游信号通路期间组胺受体的特定贡献。为了实现这一目标，我们将使用药理和分子方法来阻止特定的HRS并评估体外对胆道功能的受体特异性影响。该目标的总体目标是证明：（i）我们的体内 作用特定于胆管细胞； （ii）查明负责次级信号通路激活的特定组胺受体以及对胆管细胞增殖的影响。这些研究将表明，HDC/组胺介导的作用受刺激性（H1和H2HR）和抑制（H3和H4HRS）组胺受体的激活来调节。该项目完成时，我们希望确定涉及的程度和信号传导机制，通过HDC通过组胺的自分泌合成来调节胆道上皮的增殖/损伤。预计成功完成这些研究后，获得的信息将为控制胆管细胞增殖/损害的因素提供重要的见解，这最终将有助于识别重要的信号传导途径，这些信号通路可用于开发慢性胆汁淤积性肝疾病的治疗干预措施。该研究介绍了一个新颖的概念，即HDC可能是管理胆道疾病的重要治疗靶点。虽然HDC和组胺合成的下调对于抑制胆道增生可能很重要，但HDC的过表达（导致组胺释放增强）可能是刺激与胆汁损伤有关的胆汁胆汁增殖的关键。