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Unraveling the Role of NADPH Oxidase in Inflammation-associated Pancreatic Diseases

揭示 NADPH 氧化酶在炎症相关胰腺疾病中的作用

基本信息

批准号：
10006913
负责人：
Weiqin Lu
金额：
$ 33.61万
依托单位：
STATE UNIVERSITY NEW YORK STONY BROOK
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-20 至 2020-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10006913
关键词：
Ablation Acinar Cell Chronic Clinical Cysteine Data Disease Docking Duct (organ) structure Ductal Enzymes Fibrosis Generations Hospitalization Human Hyperactive behavior Inflammation Inflammation Mediators Inflammatory KRAS2 gene Knowledge Lesion Link Mediator of activation protein Medical Metaplasia Modification Molecular Morbidity - disease rate Mus Mutation NADPH Oxidase Oxidation-Reduction Pancreas Pancreatic Diseases Pancreatic Ductal Adenocarcinoma Pancreatic Intraepithelial Neoplasia Pancreatitis Pathogenesis Pathologic Pathology Patients Prevention Preventive Reactive Oxygen Species Risk Factors Role Signaling Molecule Stimulus Testing Therapeutic Tissue Sample Treatment Efficacy Work base chronic pancreatitis design effective intervention feeding gastrointestinal mortality mouse model mutant mutant mouse model novel pancreas development

项目摘要

Abstract Pancreatic inflammation is the major cause of gastrointestinal-related clinical morbidity and mortality, and effective therapeutic strategies against pancreatic inflammatory diseases remain an unmet medical need. Inflammation is a common feature in the pathogenesis of pancreatitis and associated acinar-to-ductal metaplasia (ADM), pancreatic intraepithelial neoplasia (PanIN) lesions, and pancreatic ductal adenocarcinoma (PDAC). Given the prominent role of inflammation in the spectrum of pancreatic pathologies, understanding pancreas- specific inflammatory mechanisms is critical for the prevention and treatment of the associated diseases. Inflammation is known to induce reactive oxygen species (ROS). Among known causal factors, ROS act as both a signaling molecule and a mediator of inflammation. Wild-type KRAS is subject to ROS modification on cysteine of the redox-sensitive NKC118D motif leading to a transient hyperactivation. KRAS mutants are observed in ~30% of patients with chronic pancreatitis, suggesting the critical role of KRAS mutations in pancreatic inflammation. In the past thirty years, mutant KRAS has been viewed as being locked in a constitutively active state. However, recent studies have found that mutant KRAS, at an endogenous level, is not constitutively active but can be hyper-activated by inflammatory insults leading to sustained inflammation, irreversible ADM, and PanIN lesions. However, the molecular mediator and mechanism linking inflammation to mutant KRAS hyperactivation and associated pathologies remain elusive. Studies have shown that NADPH oxidases (NOXs) are a major mediator of pancreatitis-induced inflammation and major enzymes activated by mutant KRAS for the generation of ROS. However, whether mutant KRAS is subject to the same ROS modification as wild-type KRAS leading to the observed hyperactivity in the context of inflammation is unknown. The objective of this proposal is to identify the molecular mediator and unravel the underlying mechanism on how inflammation promotes mutant KRAS hyperactivation and associated pancreatic pathologies. Notably, by ablating the NOX-docking subunit p22phox in mice expressing an endogenous level of KRASG12D/+ in pancreatic acinar cells, we demonstrate that NOX inhibition considerably curbs KRASG12D/+ hyperactivation, suggesting that NOX is not only a downstream effector but also a potential upstream regulator of KRASG12D. Thus, NOX and KRASG12D potentially form a co-activation feed-forward loop necessary to induce chronic inflammation, irreversible ADM, and PanIN lesions. We hypothesize that under inflammation, NOX generates ROS to modify the redox-sensitive motif of KRASG12D, leading to KRASG12D hyperactivation and associated pathologies. Our hypothesis will be tested with three specific aims in mouse models in the context of inflammatory insults. Aim 1 is to determine the role of NOX in pancreatic inflammation. Aim 2 is to determine if NOX is necessary for KRASG12D hyperactivation, sustained inflammation, irreversible ADM, and PanIN lesions. Aim 3 is to determine if the redox-sensitive NKC118D motif is required for KRASG12D hyperactivation and associated pathologies. Information gained in our studies will fill the outstanding knowledge gap on how inflammatory insults promote mutant KRAS hyperactivation and associated pathologies and guide the design of novel preventive and therapeutic strategies against these diseases in humans.

摘要