Coxsackieviral pancreatitis: autophagy, proteolysis, and inflammation

柯萨奇病毒性胰腺炎：自噬、蛋白水解和炎症

• 批准号: 9225171
• 负责人: J. Lindsay Whitton
• 金额: $ 66.76万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-04 至 2020-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9225171
• 关键词: Ablation; Acinar Cell; Address; Affect; American; Animals; Autophagocytosis; Bacterial Infections; Cells; Cost of Illness; Coxsackie Viruses; Data; Defect; Disease; Enterovirus; Evolution; Family Picornaviridae; Gene Expression; Goals; Grant; Immune; In Vitro; Infection; Inflammation; Interferons; Interruption; Knockout Mice; Lead; Life Cycle Stages; Link; Mediating; Messenger RNA; Mus; One-Step dentin bonding system; Pancreas; Pancreatitis; Pathology; Pathway interactions; Proteins; Proteolysis; Recruitment Activity; Role; Signal Transduction; Site; Testing; Toxin; Translations; Trypsin; Trypsinogen; Viral; Viral Proteins; Virus; Virus Diseases; Virus Replication; combat; cost; experimental study; in vivo; public health relevance; receptor; receptor expression; therapeutic target; tissue/cell culture

DESCRIPTION (provided by applicant): Coxsackievirus B3 (CVB3), an enterovirus in the picornavirus family, is a frequent infectious cause of pancreatitis, a common, serious, and costly disease. Some forms of pancreatitis are known to involve the autophagy pathway; e.g., toxins that block late steps in the pathway can trigger the disease, perhaps because the blockade causes activation of intracellular trypsinogen. Paradoxically, complete inactivation of autophagy protects against those types of pancreatitis. Therefore, at least those forms of pancreatitis require that the pathway be both (i) active and (ii) blocked at a late stage. Autophagy is upregulated during, and often combats, many viral and bacterial infections. Predictably, evolution has led to several viruses developing mechanisms by which to evade the inhibitory effects of the pathway, and studies have suggested that some viruses - including CVB3 - have gone one step further, actively exploiting autophagy to enhance their replication. My lab has shown that, in acinar cells in vivo, CVB3 interrupts a late stage of the autophagy pathway. We therefore hypothesized that there might be a link between this effect of CVB3 on the autophagy pathway, and the virus' ability to cause pancreatitis. We wished to test this idea in vivo, (i.e., n the living animal, not only in tissue culture cells). To achieve this goal, we have recently developed conditional KO mice (Atg5f/f/Cre+ mice) in which a key protein in the autophagy pathway, Atg5, has been deleted only in pancreatic acinar cells. Using these mice, we have shown that CVB3 benefits from an intact autophagy pathway without which CVB3 replication in the pancreas is severely curtailed. Furthermore, virus-induced pancreatitis is dramatically reduced in the Atg5f/f/Cre+ mice. Thus, like some other types of pancreatitis, CVB pancreatitis requires that autophagy be active (as it is in wt mice), but dysfunctional (because the virus blocks the pathway). Furthermore, our unpublished data show that CVB3 infection induces autophagy-dependent trypsin activity inside acinar cells. These and other data lead me to propose that there is a common cause for all pancreatitides, viral and non- viral; I propose that they result from a late blockade of the autophagy pathway, which leads to cleavage of intracellular trypsinogen, unleashing trypsin activity inside the cell. These issues will be investigated in Aims 1 & 2. I further hypothesize that the trypsin-initiated damage can be exacerbated by T1IFN signaling into acinar cells; this will be investigated in Aim 3. If these concepts are validated, autophagy and T1IFNs would become key therapeutic targets for all forms of this currently-untreatable disease. There are three Specific Aims. Aim 1. To better define interactions among CVB3, autophagy, and trypsinogen in acinar cells in vivo. Aim 2. To evaluate how T1IFN signaling directly into acinar cells affects viral pancreatitis. Aim 3. To evaluate the role of T1IFNs in recruiting immune cells to the virus-infected pancreas.

描述（由申请人提供）：Picornavirus家族中的肠病毒Coxsackievivirus B3（CVB3）是胰腺炎的经常感染原因，一种常见，严重且昂贵的疾病。已知某些形式的胰腺炎涉及自噬途径。例如，阻断途径后期步骤的毒素可能会触发疾病，这可能是因为封锁会导致细胞内胰蛋白酶原的激活。矛盾的是，自噬的完全失活可防止这些类型的胰腺炎。因此，至少那些形式的胰腺炎要求途径既具有（i）活跃，并且（ii）在后期被阻塞。自噬在许多病毒和细菌感染期间，经常会打击中上调。可以预见的是，进化导致了几种病毒开发了逃避途径抑制作用的机制，研究表明，某些病毒（包括CVB3）已进一步迈进了一步，积极利用自噬来增强其复制。我的实验室表明，在体内腺泡细胞中，CVB3中断了自噬途径的后期。因此，我们假设CVB3对自噬途径的这种影响与病毒引起胰腺炎的能力之间可能存在联系。我们希望在体内（即，在组织培养细胞中）测试这个想法（即活动物）。为了实现这一目标，我们最近开发了有条件的KO小鼠（ATG5F/F/CRE+小鼠），其中仅在胰腺腺泡细胞中删除了自噬途径中的关键蛋白ATG5。使用这些小鼠，我们已经表明，CVB3受益于完整的自噬途径，而胰腺中的CVB3复制严重限制了。此外，在ATG5F/F/CRE+小鼠中，病毒诱导的胰腺炎大大降低。因此，像其他一些类型的胰腺炎一样，CVB胰腺炎要求自噬要活跃（如在WT小鼠中），但功能失调（因为该病毒阻止了途径）。此外，我们未发表的数据表明，CVB3感染诱导腺泡细胞内的自噬依赖性胰蛋白酶活性。这些和其他数据使我提出所有胰腺，病毒和非病毒的共同原因。我建议它们是由于对自噬途径的后期封锁而导致的，这导致细胞内胰蛋白酶原的裂解，释放细胞内的胰蛋白酶活性。这些问题将在目标1和2中进行研究。我进一步假设，T1IFN信号传导到腺泡细胞中可能会加剧胰蛋白酶引起的损伤。这将在AIM 3中进行调查。如果这些概念得到了验证，则自噬和T1IFN将成为目前无法处理疾病的所有形式的关键治疗靶标。有三个特定的目标。目的1。更好地定义体内腺泡细胞中CVB3，自噬和胰蛋白酶原之间的相互作用。目的2。评估T1IFN如何直接信号到腺泡细胞中影响病毒胰腺炎。目的3。评估T1IFN在募集免疫细胞对病毒感染胰腺中的作用。