Chymotrypsin in pancreatitis

摘要 这笔赠款的主要目标是使用转基因小鼠模型来确定如何 人类胰凝乳素的基因变化增加了慢性胰腺炎的风险。以前的研究 在人和小鼠模型中证明了糜蛋白酶对胰腺炎的保护作用。 在这个提议中，最重要的假设是保护性胰凝乳素功能的丧失导致 在其他遗传或环境危险因素的背景下的胰腺炎 胰腺内胰酶激活。为了证明这一观点，CTRB1缺失的小鼠品系(Ctrb1-del)将 与携带各种胰腺炎风险等位基因的小鼠杂交，或将暴露在酒精饮食中。 虽然CTRB1缺失的小鼠在诱发疾病时表现出高水平的胰腺炎反应 实验上是通过蓝蓝蛋白刺激；它们不会自然发展为胰腺炎。介绍 在胰凝乳素缺乏的环境中的其他危险因素被预测会导致自发性 胰腺炎的发生和发展。或者，小鼠将表现出对蓝蛋白的附加敏感性- 诱导性胰腺炎。将研究以下具体目标。(1)糜蛋白酶缺乏症协同作用 胰酶原突变会导致胰腺炎。在这个目的中，假设是小鼠缺乏 小鼠胰凝乳酶和携带阳离子胰蛋白酶原(亚型T7)的突变将产生 自发性急性胰腺炎，将进展为慢性胰腺炎。或者，老鼠会表现出 增加对雨蛙素诱导的胰腺炎的易感性。通过组合调整基因剂量 杂合子和纯合子等位基因的差异应导致发病年龄和/或严重程度的不同。(2) 胰凝乳酶和胰蛋白酶抑制剂在胰腺炎中的联合作用不足。为了达到这个目的，Ctrb1-del小鼠 将与SPINK1缺失的菌株(Spink1-KO)或携带T7胰酶原的小鼠杂交 带有p.G199R突变的等位基因，该突变传递抑制剂降解特性(功能同源 人中胰酶)。假设是胰凝乳酶和胰蛋白酶联合缺乏的小鼠 抑制剂将发展为自发性胰腺炎或将表现出更严重的蓝蛋白- 诱导性胰腺炎。(3)胰凝乳素缺乏状态下的酒精性胰腺炎。在这个目标中， 胰凝乳蛋白酶缺陷小鼠将被喂以Lieber-DeCarli酒精液体饮食。假设是，在 胰凝乳蛋白酶缺乏性酒精可通过以下途径引起自发性胰腺炎 选择性上调胰酶原。成功完成这些目标将提供决定性的 有证据表明，人类胰凝乳蛋白酶基因的改变通过以下方式促进胰腺炎的发展 与其他遗传和环境因素相互作用，增加胰腺内胰酶活性。

ABSTRACT The main objective of this grant is to use genetically engineered mouse models to determine how genetic changes in human chymotrypsin increase risk for chronic pancreatitis. Previous studies demonstrated the protective role of chymotrypsin against pancreatitis in humans and in mouse models. In this proposal, the overarching hypothesis is that loss of protective chymotrypsin function leads to pancreatitis in the context of additional genetic or environmental risk factors that facilitate intrapancreatic trypsin activation. To prove this notion, a CTRB1-deleted mouse strain (Ctrb1-del) will be crossed with mice carrying various pancreatitis risk alleles or will be exposed to an alcohol diet. Although CTRB1-deleted mice show heightened pancreatitis responses when disease is induced experimentally by cerulein stimulation; they do not develop pancreatitis naturally. Introduction of additional risk factors in the setting of chymotrypsin deficiency is predicted to result in the spontaneous onset and progression of pancreatitis. Alternatively, mice will exhibit additive susceptibility to cerulein- induced pancreatitis. The following specific aims will be studied. (1) Chymotrypsin deficiency synergizes with trypsinogen mutations to cause pancreatitis. In this aim, the hypothesis is that mice deficient in chymotrypsin and carrying mutations in mouse cationic trypsinogen (isoform T7) will develop spontaneous acute pancreatitis that will progress to chronic pancreatitis. Alternatively, mice will exhibit increased susceptibility to cerulein-induced pancreatitis. Adjusting gene dosage through combinations of heterozygous and homozygous alleles should result in variations in age of onset and/or severity. (2) Combined insufficiency of chymotrypsin and trypsin inhibitor in pancreatitis. In this aim, Ctrb1-del mice will be crossed either with a SPINK1-deleted strain (Spink1-KO) or with mice carrying a T7 trypsinogen allele with the p.G199R mutation, which conveys inhibitor-degrading properties (functional ortholog of human mesotrypsin). The hypothesis is that mice with combined deficiency in chymotrypsin and trypsin inhibitor will develop either spontaneous pancreatitis or will exhibit increased severity of cerulein- induced pancreatitis. (3) Alcoholic pancreatitis in the setting of chymotrypsin deficiency. In this aim, chymotrypsin-deficient mice will be fed the Lieber-DeCarli alcohol liquid diet. The hypothesis is that in the background of chymotrypsin-deficiency alcohol will cause spontaneous pancreatitis through selective upregulation of trypsinogen. Successful completion of these aims will offer conclusive evidence that alterations in chymotrypsin genes in humans promote the development of pancreatitis by interacting with other genetic and environmental factors that increase intrapancreatic trypsin activity.