BACKGROUND The premature activation of digestive enzyme zymogens within pancreatic acinar cells is an important early feature of acute pancreatitis. Supraphysiological concentrations of cholecystokinin (CCK) cause intrapancreatic zymogen activation and acute pancreatitis. Stimulation of vacuolar ATPase (vATPase) activity is required for zymogen activation in pancreatic acinar cells. Parkin, a multiprotein E3 ubiquitin ligase complex, promotes vATPase ubiquitination and degradation, which inhibits vATPase activity. Docosahexaenoic acid (DHA), an omega-3 fatty acid, exerts anti-inflammatory effects. It is reported to bind to G-protein coupled receptor 120 (GPR120) and GPR40. DHA induces the degradation of certain proteins by activating ubiquitin-proteasome system in various cells. This study aimed to investigate whether DHA induces Parkin and inhibits vATPase activity, resulting in zymogen inactivation in pancreatic acinar AR42J cells stimulated with cerulein, a CCK analog. RESULTS Cerulein induced the translocation of the cytosolic V1 domain (E subunit) of vATPase to the membrane, which indicated vATPase activation, and zymogen activation in AR42J cells. DHA suppressed the association of the vATPase with membranes, and zymogen activation (increased trypsin activity and amylase release) induced by cerulein. Pretreatment with a GPR120 antagonist AH-7614, a GPR40 antagonist DC260126, or an ubiquitination inhibitor PYR-41 reduced the effect of DHA on cerulein-induced zymogen activation. Treatment with PYR-41 reversed the DHA-induced decrease in vATPase activation in cerulein-treated cells. Furthermore, DHA increased the level of Parkin in membranes of cerulein-treated cells. CONCLUSIONS DHA upregulates Parkin which inhibits vATPase-mediated zymogen activation, via GPR120 and GPR40, in cerulein-stimulated pancreatic acinar cells.

中文翻译：

---

二十二碳六烯酸通过抑制蓝藻素刺激的胰腺腺泡细胞中液泡ATPase的活化来抑制酶原的活化。

背景技术胰腺腺泡细胞内的消化酶酶原的过早活化是急性胰腺炎的重要早期特征。超生理浓度的胆囊收缩素（CCK）引起胰腺内酶原激活和急性胰腺炎。胰腺液泡细胞中的酶原激活需要刺激液泡ATPase（vATPase）活性。Parkin是一种多蛋白E3泛素连接酶复合物，可促进vATPase泛素化和降解，从而抑制vATPase活性。二十二碳六烯酸（DHA）是一种omega-3脂肪酸，具有抗炎作用。据报道它与G蛋白偶联受体120（GPR120）和GPR40结合。DHA通过激活各种细胞中的泛素-蛋白酶体系统来诱导某些蛋白质的降解。这项研究旨在调查DHA是否诱导帕金蛋白并抑制vATPase活性，从而导致CCK类似物cerulein刺激的胰腺腺泡AR42J细胞中的酶原失活。结果Cerulein诱导vATPase的胞质V1结构域（E亚基）易位至膜，这表明vATPase活化和酶原活化在AR42J细胞中。DHA抑制了vATPase与膜的缔合，并抑制了铜绿素诱导的酶原激活（增加了胰蛋白酶的活性和淀粉酶的释放）。用GPR120拮抗剂AH-7614，GPR40拮抗剂DC260126或泛素化抑制剂PYR-41进行的预处理可降低DHA对青霉素诱导的酶原激活的影响。用PYR-41进行的治疗逆转了DHA诱导的，经轻皮素处理的细胞中vATPase活化的降低。此外，DHA增加了经铜粉蛋白处理的细胞膜中的帕金水平。结论DHA可以通过GPR120和GPR40上调由轻蓝素刺激的胰腺腺泡细胞中抑制vATPase介导的酶原活化的DHA。