Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Genética, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Inmunología, Genética y Metabolismo (INIGEM), Buenos Aires, Argentina.
Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Cátedra de Fisiología, Buenos Aires, Argentina; CONICET-Universidad de Buenos Aires, Instituto de Química y Metabolismo del Fármaco (IQUIMEFA), Buenos Aires, Argentina.
Biochim Biophys Acta Mol Basis Dis. 2019 Feb 1;1865(2):485-493. doi: 10.1016/j.bbadis.2018.12.004. Epub 2018 Dec 7.
Increasing evidence shows that the endoplasmic reticulum (ER) stress is an early event that injures pancreatic acinar cells and contributes to the pathogenesis of acute pancreatitis. In the present work we sought to establish whether atrial natriuretic peptide (ANP) alleviated ER stress in rats with cerulein-induced pancreatitis. The major components of the unfolded protein response (UPR) and their downstream effectors were assessed by immunoblotting or fluorimetry and the ultrastructure of ER evaluated by electron transmission microscopy. Cross-talk with autophagy was evaluated by beclin-1 expression. ANP reduced binding immunoglobulin protein (Bip) expression (UPR major controller) which under non-stress conditions keeps inactive the stress sensor proteins: protein kinase-like ER kinase (PERK), inositol-requiring enzyme-1 (IRE1) and activating transcription factor 6 (ATF6). Although ANP did not change PERK expression it decreased p-eIF2α and enhanced downstream effector CHOP, suggesting that ANP stimulates ER-dependent apoptosis. In accordance, ANP also decreased Bcl2 expression and enhanced proapoptotic proteins Bax and Bak. The atrial peptide enhanced ATF6 expression and although it did not affect IRE1/sXBP1 signaling, it increased caspase-2 activity, also involved in ER-dependent apoptosis. Furthermore, ANP decreased beclin-1 expression. The ultrastructure of the RE revealed decreased swelling and conserved ribosomes in the presence of ANP. Present findings support that ANP alleviates ER stress in acute pancreatitis by modulating the three branches of the UPR and stimulates ER-dependent apoptosis. Gaining insights into the modulation of ER stress may help to develop specific therapeutic strategies for acute pancreatitis and/or medical interventions at risk of its developing like endoscopic retrograde cholangiopancreatography.
越来越多的证据表明，内质网（ER）应激是损伤胰腺腺泡细胞并导致急性胰腺炎发病机制的早期事件。在本工作中，我们试图确定心钠肽（ANP）是否减轻了 Cerulein 诱导的胰腺炎大鼠的 ER 应激。通过免疫印迹或荧光法评估未折叠蛋白反应（UPR）的主要成分及其下游效应物，并通过电子透射显微镜评估 ER 的超微结构。通过 beclin-1 表达评估与自噬的串扰。ANP 降低结合免疫球蛋白蛋白（Bip）表达（UPR 主要控制器），在非应激条件下，Bip 使应激传感器蛋白：蛋白激酶样内质网激酶（PERK）、肌醇需求酶 1（IRE1）和激活转录因子 6（ATF6）保持非活性。尽管 ANP 不改变 PERK 表达，但它降低了 p-eIF2α 并增强了下游效应物 CHOP，表明 ANP 刺激 ER 依赖性细胞凋亡。相应地，ANP 还降低了 Bcl2 表达并增强了促凋亡蛋白 Bax 和 Bak。心钠肽增强了 ATF6 的表达，尽管它不影响 IRE1/sXBP1 信号，但它增加了半胱天冬酶-2 活性，也参与 ER 依赖性细胞凋亡。此外，ANP 降低了 beclin-1 的表达。RE 的超微结构显示，在存在 ANP 的情况下，肿胀减轻，核糖体保持。目前的研究结果支持 ANP 通过调节 UPR 的三个分支减轻急性胰腺炎中的 ER 应激，并刺激 ER 依赖性细胞凋亡。深入了解 ER 应激的调节可能有助于为急性胰腺炎开发特定的治疗策略，或为有发展为急性胰腺炎风险的医疗干预措施提供医学干预。
