Neural Regulation of Pancreatic Function

胰腺功能的神经调节

• 批准号: 8012161
• 负责人: NIGEL W BUNNETT
• 金额: $ 10万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-02-01 至 2011-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8012161
• 关键词: 4 hydroxynonenal; Abdominal Pain; Adhesions; Afferent Neurons; Agonist; Aldehydes; Analgesics; Animals; Anti Inflammatory Analgesics; Anti-Inflammatory Agents; Arachidonic Acids; Attenuated; Behavior; Behavior Therapy; Blood Vessels; Blood capillaries; Bradykinin; Calcitonin; Calcitonin Gene-Related Peptide; Cell surface; Cleaved cell; Endocytosis; Endosomes; Endothelial Cells; Endothelin-converting enzyme 1; Enzymes; Event; Experimental Models; Extracellular Fluid; Extravasation; Family; Fiber; G-Protein-Coupled Receptors; Gated Ion Channel; Goals; Human; Hyperemia; Infiltration; Inflammation; Inflammation Mediators; Inflammatory; Injection of therapeutic agent; Intractable Pain; Ion Channel; Learning; Ligands; Lipid Peroxidation; Mechanics; Mediating; Mediator of activation protein; Membrane Lipids; Metalloendopeptidases; Modeling; Morbidity - disease rate; Mus; Neprilysin; Nerve Growth Factors; Neurogenic Inflammation; Neurokinin A; Neurons; Neuropeptide Receptor; Neuropeptides; Nociception; PAR-2 Receptor; Pain; Pancreas; Pancreatic duct; Pancreatitis; Pathway interactions; Peptide Hydrolases; Peptide Signal Sequences; Peptides; Peripheral; Plasma; Play; Process; Protease Inhibitor; Rattus; Reactive Oxygen Species; Receptor Activation; Receptor Protein-Tyrosine Kinases; Recombinants; Recycling; Resistance; Role; Sensory; Sensory Nerve Endings; Signal Transduction; Spinal; Spinal Cord; Spinal Ganglia; Spinal cord posterior horn; Stimulus; Stress; Substance P; Substance P Receptor; Symptoms; Testing; Therapeutic; Therapeutic Agents; Tissues; Trypsin; Vanilloid; Wild Type Mouse; acute pancreatitis; afferent nerve; arteriole; capillary; design; inflammatory pain; inhibitor/antagonist; lung injury; member; mortality; neuronal cell body; neuroregulation; neutrophil; novel; novel therapeutics; overexpression; prevent; public health relevance; receptor; receptor recycling; receptor-activity-modifying protein; research study; venule

DESCRIPTION (provided by applicant): Acute pancreatitis is an inflammatory condition with 5-10% mortality rate. Severe abdominal pain is the most prominent symptom, however the mechanisms of pancreatic inflammatory pain are poorly understood and consequently the therapeutic strategies are unsophisticated. The long term goal of this proposal is to identify the major mediators of pancreatic neurogenic inflammation and pain and to develop novel therapies for these conditions. We propose to study pathways involved both in the initiation and termination of inflammatory pain in the pancreas. Although ion channels of the transient receptor potential (TRP) family are known to promote inflammation and pain in somatic models, and we have shown that TRPV1 mediates pancreatic inflammatory pain via the release of neuropeptides both in the pancreas and spinal cord, whether the newer ion channels TRPV4 and TRPA1 participate in pancreatic inflammation and pain is unknown. TRPV4 responds to mechanical sheer stress, osmotic changes, as well as certain arachidonic acid metabolites released during inflammation. TRPV4 is expressed by pancreatic sensory neurons and our preliminary results show that it mediates nociception since either injection of TRPV4 agonists into the pancreatic duct or initiation of experimental pancreatitis result in activation of nociceptive neurons in the spinal cord (assessed by fos expression) in wild-type mice with diminished effects in TRPV4-/- animals. Moreover, proteases such as trypsin, that are prematurely-activated in the inflamed pancreas and can cleave and activate protease activated receptor 2 (PAR2), sensitize TRPV4. Experiments are designed to define the mechanisms by which inflammatory mediators sensitize TRPV4 in pancreatic neurons to promote the release of neuropeptides that cause neurogenic inflammation and pain. We have recently discovered that 4-hydroxynonenal (HNE), an aldehyde generated by the action of reactive oxygen species (ROS) on membrane lipids, is an endogenous agonist of TRPA1 which causes peptide release, neurogenic inflammation and pain. TRPA1 promotes pancreatic inflammatory pain since our preliminary results show that intraductal agonists and experimental pancreatitis stimulate fos expression and inflammation in TRPA1 wild-type mice with markedly reduced effects in TRPA1-/- animals. Experiments are designed to define the expression of TRPA1 in pancreatic neurons, to determine the effects of lipid peroxidation products such as HNE on neurogenic pancreatic inflammation and nociception, to determine how the pro-inflammatory peptide bradykinin sensitizes TRPA1, and to investigate the contribution of TRPA1 to neurogenic inflammation and pain in several models of experimental pancreatitis. Finally we will investigate pathways that terminate pancreatic inflammation by examining the role of metalloendopeptidases that degrade proinflammatory peptides on the cell surface and in endosomes. We will determine whether neutral endopeptidase (NEP), a cell surface enzyme that degrades at least 11 peptides including substance P and bradykinin, attenuates pancreatic inflammation and pain, and to evaluate whether administration of recombinant human NEP is a novel anti-inflammatory and analgesic agent. We have recently discovered that endothelin converting enzyme-1 (ECE-1) degrades pro-inflammatory peptides in endosomes to thereby promote recycling and resensitization of endocytosed receptors. Experiments are designed to determine whether ECE-1 inhibitors, by preventing receptor recycling, inhibit resensitization of neurogenic inflammation in the pancreas, and are thus novel anti-inflammatory agents. PUBLIC HEALTH RELEVANCE: Pancreatic inflammation results in morbidity and mortality, with severe intractable pain. The mechanisms of acute pancreatitis and pancreatitis pain are very poorly understood. The overall objective of our proposal is to identify key mediators of pancreatic inflammation and pain, and to evaluate novel therapies for these conditions. Specifically, we will determine the role of newly-identified ion channels on pancreatic sensory nerves. Once activated or sensitized in the inflamed pancreas, these channels induce the release of neuropeptides from sensory nerves in the pancreas and the spinal cord, where peptides cause neurogenic inflammation and pain, respectively. Thus, antagonists of these channels may prevent pancreatic inflammatory pain. We will also evaluate whether recombinant human peptidases, which degrade proinflammatory and nociceptive peptides, ameliorate inflammatory pain, and are thus novel therapeutic agents. We determine whether inhibitors of peptidases in endosomes, that regulate the recycling and resensitization of neuropeptide receptors, prevent the sustained signaling of these peptides and thereby ameliorate neurogenic inflammation and pain.

描述（由申请人提供）：急性胰腺炎是一种炎症性疾病，死亡率为5-10%。严重腹痛是最突出的症状，然而胰腺炎性疼痛的机制知之甚少，因此治疗策略不成熟。这项提案的长期目标是确定胰腺神经源性炎症和疼痛的主要介质，并为这些疾病开发新的治疗方法。我们建议研究参与胰腺炎性疼痛的启动和终止的途径。虽然已知瞬时受体电位（TRP）家族的离子通道在体细胞模型中促进炎症和疼痛，并且我们已经表明TRPV 1通过胰腺和脊髓中神经肽的释放介导胰腺炎性疼痛，但较新的离子通道TRPV 4和TRPA 1是否参与胰腺炎症和疼痛尚不清楚。TRPV 4对机械剪切应力、渗透压变化以及炎症期间释放的某些花生四烯酸代谢物作出反应。TRPV 4由胰腺感觉神经元表达，我们的初步结果表明，它介导伤害性感受，因为将TRPV 4激动剂注射到胰管中或引发实验性胰腺炎导致野生型小鼠脊髓中伤害性感受神经元的激活（通过fos表达评估），而在TRPV 4-/-动物中的作用减弱。此外，在发炎的胰腺中过早激活并可切割和激活蛋白酶激活受体2（PAR 2）的蛋白酶如胰蛋白酶使TRPV 4敏化。实验旨在确定炎症介质使胰腺神经元中的TRPV 4敏感以促进引起神经源性炎症和疼痛的神经肽的释放的机制。我们最近发现，4-羟基壬烯醛（HNE），一种由活性氧（ROS）对膜脂质的作用产生的醛，是TRPA 1的内源性激动剂，其引起肽释放，神经源性炎症和疼痛。TRPA 1促进胰腺炎性疼痛，因为我们的初步结果表明，导管内激动剂和实验性胰腺炎刺激TRPA 1野生型小鼠中的fos表达和炎症，而在TRPA 1-/-动物中的作用显著降低。实验旨在确定TRPA 1在胰腺神经元中的表达，以确定脂质过氧化产物如HNE对神经源性胰腺炎症和伤害感受的影响，以确定促炎肽缓激肽如何使TRPA 1敏感，并研究TRPA 1在几种实验性胰腺炎模型中对神经源性炎症和疼痛的贡献。最后，我们将通过检测金属内肽酶降解细胞表面和内体中促炎肽的作用来研究终止胰腺炎症的途径。我们将确定是否中性内肽酶（NEP），细胞表面酶，降解至少11肽，包括P物质和缓激肽，减轻胰腺炎症和疼痛，并评估重组人NEP的管理是否是一种新的抗炎和镇痛剂。我们最近发现内皮素转换酶-1（ECE-1）降解内体中的促炎肽，从而促进内吞受体的再循环和再敏感。设计实验以确定ECE-1抑制剂是否通过阻止受体再循环来抑制胰腺中神经源性炎症的再敏化，并且因此是新的抗炎剂。公共卫生相关性：胰腺炎导致发病率和死亡率，并伴有严重的顽固性疼痛。急性胰腺炎和胰腺炎疼痛的机制知之甚少。我们建议的总体目标是确定胰腺炎症和疼痛的关键介质，并评估这些疾病的新疗法。具体来说，我们将确定新发现的离子通道对胰腺感觉神经的作用。一旦在发炎的胰腺中被激活或致敏，这些通道诱导神经肽从胰腺和脊髓中的感觉神经释放，其中肽分别引起神经源性炎症和疼痛。因此，这些通道的拮抗剂可以预防胰腺炎性疼痛。我们还将评估重组人肽酶，降解促炎和伤害感受肽，改善炎性疼痛，因此是新的治疗药物。我们确定是否抑制剂的内体中的肽酶，调节神经肽受体的回收和再敏化，防止这些肽的持续信号，从而改善神经源性炎症和疼痛。