Acinar Biology and Pancreatic Disease

腺泡生物学和胰腺疾病

• 批准号: 8675844
• 负责人: GUY E GROBLEWSKI
• 金额: $ 32.03万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-08 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8675844
• 关键词: Acinar Cell; Acinus organ component; Acute; Affect; American; Apical; Biogenesis; Biology; Cell membrane; Cells; Cytoplasmic Granules; Cytoplasmic Vesicles; Data; Development; Digestion; Disease; Endocrine; Endosomes; Ensure; Enzyme Activation; Enzyme Inhibition; Enzyme Precursors; Enzymes; Exocrine Glands; Exocrine pancreas; Exocytosis; Food; Functional disorder; Gland; Hybrids; Hydrolase; Intestines; Knowledge; Lead; Lysosomes; Malignant neoplasm of pancreas; Mediating; Membrane; Membrane Proteins; Metabolism; Minor; Molecular; Mus; Nutrient; Pancreas; Pancreatic Diseases; Pancreatitis; Pathway interactions; Phase; Phosphatidylinositol Phosphates; Phosphorylation; Physiological; Play; Population; Process; Proteins; Reaction; Regulation; Regulatory Pathway; Reporting; Resistance; Role; System; TPD52 gene; Testing; Therapeutic; Vesicle; Zymogen Granules; absorption; acute pancreatitis; apical membrane; base; calcium-regulated heat-stable protein 28; cell type; cellular targeting; gastrointestinal system; genetic regulatory protein; insight; mortality; novel; phosphatidylinositol 3,5-diphosphate; premature; receptor; relating to nervous system; research study; response; syntaxin 3; therapeutic development; trafficking; tumor; vesicle-associated membrane protein

DESCRIPTION (provided by applicant): Exocrine pancreatic acinar cells manufacture, store and release large quantities of hydrolytic enzymes into the intestine that are essential for nutrient digestion and absorption. As food is derived from cellular material, acinar cells retain protective mechanisms to ensure digestive enzymes are not prematurely activated until reaching the intestine. Indeed, aberrant dysregulation of the acinar secretory pathway and premature activation of enzymes has been tied to the development of pancreatitis and pancreatic cancer, which affect over 48,000 Americans each year. It is widely believed that premature digestive enzyme activation is caused by abnormal interactions of the secretory and lysosomal pathways in acini. Thus, knowledge of the basic molecular mechanisms which orchestrate the normal interactions of these pathways is critical to understanding the pathophysiology of pancreatic disease. This proposal investigates a previously unrecognized and important regulatory pathway by which acinar cells modulate digestive enzyme trafficking within the secretory and lysosomal pathways and accordingly regulate digestive enzyme secretion. We recently reported that acinar cells express two distinct populations of zymogen granules (ZGs) based on the expression of the exocytic regulatory proteins VAMP2 and 8. Moreover, our data indicate that maturation of VAMP8 ZGs is directed by Tumor Protein D52 (aka CRHSP-28), which we have shown is uniquely expressed in acini and directly regulates Ca2+-dependent secretion. Unexpectedly, D52 was localized to a unique endosome and lysosome related compartment in acini that we term the endo-lysosomal compartment. Moreover, in CHO-K1 cells, D52 directly regulates lysosmal membrane exocytosis and when over-expressed induces a massive accumulation of cytoplasmic vesicles. This proposal aims to delineate the precise functional roles of VAMP2- and VAMP8- positive ZGs in the acinar secretory response and will test the central hypothesis that D52-regulated trafficking through the endo-lysosomal system controls the biogenesis/maturation of VAMP8-positive ZGs within a unique lysosome-related pathway. Specific Aim 1 will test the hypothesis that VAMP2-positive ZGs mediate the early immediate release of digestive enzymes, whereas VAMP8-positive ZGs mediate the sustained plateau phase of zymogen secretion following acinar stimulation. Specific Aim 2 will test the hypothesis that activation of PIKfyve to produce PtdIns(3,5)P2 in acini regulates endo-lysosomal trafficking to the lysosome and inhibits apical secretion during acinar hyperstimulation. Specific Aim 3 will test the hypothesis that D52 activation of the "minor regulated pathway" mediates the rapid insertion of important regulatory proteins into the apical membrane necessary for granule exocytosis. Understanding the basic molecular principles of how acini uniquely orchestrate the secretory or lysosomal compartments is key to the development of therapeutic strategies aimed at treating pancreatic disease.

描述（由申请方提供）：外分泌胰腺腺泡细胞产生、储存和释放大量水解酶进入肠道，这些水解酶是营养消化和吸收所必需的。由于食物来源于细胞物质，腺泡细胞保留保护机制，以确保消化酶在到达肠道之前不会过早激活。事实上，腺泡分泌途径的异常失调和酶的过早激活与胰腺炎和胰腺癌的发展有关，每年影响超过48，000名美国人。目前普遍认为，腺泡内分泌途径和溶酶体途径的异常相互作用导致消化酶过早激活。因此，了解协调这些途径正常相互作用的基本分子机制对于理解胰腺疾病的病理生理学至关重要。该建议调查了一个以前未被认识到的重要的调节途径，腺泡细胞通过该途径调节分泌和溶酶体途径内的消化酶运输，并相应地调节消化酶分泌。我们最近报道，腺泡细胞表达两个不同的群体的酶原颗粒（ZGs）的基础上表达的胞外调节蛋白VAMP 2和8。此外，我们的数据表明，VAMP 8 ZG的成熟是由肿瘤蛋白D52（又名CRHSP-28）指导的，我们已经证明，它是唯一表达在腺泡中，并直接调节Ca 2+依赖性分泌。出乎意料的是，D52定位于腺泡中独特的内体和溶酶体相关区室，我们称之为内体-溶酶体区室。此外，在CHO-K1细胞中，D52直接调节溶酶体膜胞吐作用，并且当过表达时诱导细胞质囊泡的大量积累。该提案旨在描述VAMP 2和VAMP 8阳性ZG在腺泡分泌反应中的确切功能作用，并将测试D52调节的通过内溶酶体系统的运输在独特的溶酶体相关途径内控制VAMP 8阳性ZG的生物发生/成熟的中心假设。具体目标1将检验如下假设：VAMP 2阳性ZG介导消化酶的早期立即释放，而VAMP 8阳性ZG介导腺泡刺激后酶原分泌的持续平台期。特定目的2将检验以下假设：激活PIKfyve以在腺泡中产生PtdIns（3，5）P2，调节内溶酶体向溶酶体的运输，并抑制腺泡过度刺激期间的顶端分泌。具体目标3将测试的假设，D52激活的“次要调节途径”介导的重要的调节蛋白快速插入到顶端膜颗粒胞吐所必需的。了解腺泡如何独特地协调分泌或溶酶体室的基本分子原理是开发旨在治疗胰腺疾病的治疗策略的关键。