Acinar Biology and Pancreatic Disease

腺泡生物学和胰腺疾病

• 批准号: 8429457
• 负责人: GUY E GROBLEWSKI
• 金额: $ 30.91万
• 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/8429457
• 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（由申请人提供）：外分泌胰腺腺泡细胞生产，存储和释放大量的水解酶，这对于营养消化和吸收至关重要。由于食物是源自细胞材料的，因此腺泡细胞保留了保护机制，以确保在达到肠道之前不会过早激活消化酶。实际上，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。人们普遍认为，过早的消化酶激活是由acini分泌和溶酶体途径异常相互作用引起的。因此，对这些途径正常相互作用的基本分子机制的了解对于理解胰腺疾病的病理生理学至关重要。该提案研究了一种先前未知且重要的调节途径，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，并因此调节消化酶分泌。我们最近报道说，腺泡细胞基于外粒细胞调节蛋白的表达表达了两种不同的酶原颗粒（ZGS）。出乎意料的是，D52被定位于Acini中的独特内体和与溶酶体相关的隔室，我们称其为内部溶菌体隔室。此外，在CHO-K1细胞中，D52直接调节溶酶体膜胞吐作用，并且当过表达时会诱导大量的细胞质囊泡积累。该提议旨在描述VAMP2-和VAMP8-正ZGS在腺泡分泌响应中的精确功能作用，并将检验以下假设，即D52通过内部溶血体系统控制D52调节的贩运可以控制型号的lysosome pathers of necore paths of the Endo-lysosomal系统。具体目标1将检验以下假设：VAMP2阳性ZG介导了早期立即释放消化酶，而VAMP8阳性ZGS介导腺泡刺激后Zymogen分泌的持续高原阶段。具体目标2将检验以下假设：在ACINI中激活Pikfyve以产生PTDINS（3,5）P2，调节对溶酶体的内部溶血体运输，并抑制腺泡过度刺激期间的根尖分泌。具体目标3将检验以下假设：D52激活“次要调节途径”会介导重要的调节蛋白的快速插入到颗粒胞吐作用所需的根尖膜中。了解Acini如何独特地协调分泌或溶酶体隔室的基本分子原理是旨在治疗胰腺疾病的治疗策略的关键。