Alcohol Induced Chronic Pancreatitis

描述（由申请人提供）：酒精滥用与至少70%的慢性胰腺炎（CP）和40%的急性胰腺炎病例相关。然而，只有一小部分滥用酒精的人会患上胰腺疾病。显然，还有其他生物因素易患胰腺炎，酒精滥用是一种触发机制。但这些因素是什么呢？不幸的是，迄今为止还没有动物模型已经开发出概括酒精相关的CP。因此，很难在防治这一疾病方面取得进展。然而，我们最近开发了两种新的小鼠模型，它们对酒精敏感，并且在不需要额外损伤的情况下发展为严重的CP。该模型涉及调节胰腺腺泡细胞特异性表达的突变胰蛋白酶分子。一种是在翻译时被激活的实验构建体（称为Trypon小鼠）。另一个涉及与遗传性胰腺炎相关的R122H胰蛋白酶原突变体（称为R122H小鼠）的表达。当这些突变的胰蛋白酶分子作为杂合子表达时，它们都不诱导胰腺炎或任何明显的扰动。然而，当R122G或Trypon小鼠被喂食酒精饮食时，它们会产生严重的CP。这些数据支持一个假设，即酒精敏感胰腺的因素，影响胰蛋白酶的激活或保护活性胰蛋白酶。本提案的目标是通过追求三个具体目标来了解这些影响所涉及的机制。目的#1：确定急性或慢性摄入酒精是否是表达突变胰蛋白酶的小鼠产生CP所必需的。酒精有多种影响，急性和慢性酒精的影响往往相反。重要的是要了解酒精是否需要在短期或长期在这个模型中产生慢性胰腺炎。我们还将确定酒精对胰蛋白酶活性的影响，以评估胰蛋白酶本身是否是关键机制。这些研究将共同提供有关该模型的重要基本信息。目的#2：我们将确定乙醇在这些动物中引发的腺泡细胞死亡的形式。我们假设酒精扰乱正常的细胞机制，如细胞内胰蛋白酶诱导腺泡细胞坏死。我们还将研究自噬是否参与了乙醇在该模型中的作用。目标3。确定金属硫蛋白（MT）在表达突变胰蛋白酶的酒精处理小鼠中CP发展中的作用。我们以前发现，酒精喂养会导致MT的下调，而MT通常在急性胰腺炎中起保护作用。为了了解MT在酒精相关CP中的作用，我们将研究突变型胰蛋白酶表达在MT水平高（锌处理）或低（MT缺乏）的小鼠中的作用。我们还将研究酒精减少MT表达的机制。这些新的模型和方法将为酒精和胰腺疾病之间的关系提供重要的新信息。

DESCRIPTION (provided by applicant): Alcohol abuse is associated with at least 70% of cases of chronic pancreatitis (CP) and 40% of acute pancreatitis. Yet, only a small percentage of those who abuse alcohol develop pancreatic disease. Clearly there are other biological factors which predispose to the development of pancreatitis and alcohol abuse is acting as a triggering mechanism. But what are these factors? Unfortunately, to date no animal model has been developed that recapitulates alcohol related CP. Therefore, it has been difficult to make progress against this disease. However, we have recently developed two novel mouse models which are sensitive to alcohol and develop severe CP without the need for additional insults. The models involve regulated pancreatic acinar cell specific expression of mutant trypsin molecules. One is an experimental construct that becomes activated upon translation (called Trypon mice). The other involves expression of the R122H trypsinogen mutant (called R122H mice) which is associated with hereditary pancreatitis. Neither of these mutant trypsin molecules induces pancreatitis or any obvious perturbations when expressed as a heterozygote. However, when R122G or Trypon mice are fed an alcohol diet; they develop profound CP. These data support a hypothesis that alcohol sensitizes the pancreas to factors that affect trypsin activation or protection from active trypsin. The goal of this proposal is to understand the mechanisms involved in these effects by pursuing three specific aims. Aim #1: Determine whether acute or chronic intake of alcohol is necessary to generate CP in mice expressing mutant trypsin. Alcohol has multiple effects and the effects of acute and chronic alcohol are often opposite. It will be important to understand whether alcohol is required in the short or long term to generate chronic pancreatitis in this model. We will also determine the effects of alcohol on trypsin activity to assess whether trypsin itself is the key mechanism. Together these studies will provide important basic information about the model. Aim #2: We will determine the form(s) of acinar cell death initiated in these animals by ethanol. We hypothesize that alcohol perturbs normal cellular mechanisms such that intracellular trypsin induces necrosis in acinar cells. We will also examine whether autophagy is involved in the effects of ethanol in this model. Aim #3. Determine the role of metallothionein (MT) in the development of CP in alcohol treated mice expressing mutant trypsin. We have previously found that alcohol feeding causes a down-regulation of MT, which normally plays a protective role in acute pancreatitis. To understand the role of MT in alcohol related CP we will examine the effects of mutant trypsin expression in mice with high (Zn treated) or low (MT deficient) levels of MT. We will also investigate the mechanisms of alcohol reduction of MT expression. Together these novel models and approaches will provide important new information about the relationship between alcohol and pancreatic disease.