Initiation of the Sterile Inflammatory Response in Acute Pancreatitis

描述(由申请人提供)：急性胰腺炎(AP)是由胰腺腺泡细胞损伤导致酶原激活而引发的。这种最初的侮辱导致迅速的无菌炎症反应(SIR)，其特征是水肿、细胞浸润性和进一步的腺泡细胞死亡。许多证据表明SIR在胰腺损伤中起重要作用，但腺泡细胞损伤和SIR的诱导之间的关键联系尚未确定。我们的初步数据表明，在雨蛙素诱导的急性胰腺炎中：1.在缺乏TLR9或炎症组分ASC、NLRP3和Caspase-1的情况下，SIR和腺泡细胞损伤减少。二、TLR9抑制剂可减少SIR和腺泡细胞死亡。三、在体内，TLR9的表达定位于常驻免疫细胞、内皮细胞和胰管细胞。我们假设，最初的腺泡细胞损伤释放损伤相关的分子模式(DAMP)，驻留的胰腺细胞感受到这种模式，导致SIR，从而增加腺泡细胞的死亡。目的1：鉴定胰腺湿敏细胞。(A)将构建骨髓嵌合体以确定免疫细胞和实质细胞对SIR的相对贡献。(B)选择性耗竭将决定单个细胞群体对SIR的贡献。目的2：确定炎性小体激活的哪些成分可引起腺泡细胞毒性。(A)IL-1β和IL-18，以及(B)与目标1中确定的潮湿敏感细胞共培养。目的3：确定TLR4激活在急性胰腺炎中对炎症体和TLR9信号的调节。TLR4激活调节(A)NLRP3炎症体和(B)TLR9信号的能力将在AIM 1中确定的潮湿敏感细胞中进行评估。这项拟议的工作将确定急性胰腺炎启动炎症反应的详细细胞和分子机制。

DESCRIPTION (provided by applicant): Acute pancreatitis (AP) is initiated by injury to pancreatic acinar cells resulting in zymogen activation. This initial insult induces a rapid sterile inflammatory response (SIR) characterized by edema, cellular infiltrate, and further acinar cell death. Many lines of evidence point towards the SIR having a vital role in pancreatic damage, but the crucial link between acinar cell injury and induction of the SIR has not been identified. Our preliminary data demonstrate that in caerulein-induced acute pancreatitis: i. In the absence of TLR9 or the inflammasome components ASC, NLRP3, and caspase-1 there is reduced SIR and acinar cell injury. ii. Inhibitors of TLR9 can reduce the SIR and acinar cell death. iii. TLR9 expression is localized to resident immune, endothelial, and pancreatic duct cells in vivo. We hypothesize that initial acinar cell injury releases damage associated molecular patterns (DAMPs) which are sensed by resident pancreatic cells, resulting in the SIR which increases acinar cell death. Aim 1: Identify the pancreatic DAMP-sensing cell. (a) Bone marrow chimeras will be constructed to identify the relative contribution of immune and parenchymal cells to the SIR. (b) Selective depletion will determine the contributions of individual cell populations to the SIR. Aim 2: Identify which components of inflammasome activation induce acinar cell cytotoxicity. Acinar cells will be isolated and assessed for cell death and zymogen activation in response to (a) IL-1beta and IL-18, and (b) co-culture with the DAMP-sensing cell identified in Aim 1. Aim 3: Identify the regulation of the inflammasome and TLR9 signaling by TLR4 activation in acute pancreatitis. The ability of TLR4 activation to regulate both (a) NLRP3 inflammasome and (b) TLR9 signaling will be assessed in the DAMP-sensing cells identified in Aim 1. The proposed work will identify a detailed cellular and molecular mechanism for the initiation of the inflammatory response in acute pancreatitis.