Park Yeeun, Ku Leeyeon, Lim Joo Weon, Kim Hyeyoung
Department of Food and Nutrition, Brain Korea 21 PLUS Project, College of Human Ecology, Yonsei University, Seoul, 03722, Korea.
Genes Nutr. 2020 Mar 23;15(1):6. doi: 10.1186/s12263-020-00664-2.
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.
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.
DHA upregulates Parkin which inhibits vATPase-mediated zymogen activation, via GPR120 and GPR40, in cerulein-stimulated pancreatic acinar cells.
胰腺腺泡细胞内消化酶原的过早激活是急性胰腺炎的一个重要早期特征。超生理浓度的胆囊收缩素（CCK）可导致胰腺内酶原激活和急性胰腺炎。胰腺腺泡细胞中酶原激活需要液泡型ATP酶（vATPase）活性的刺激。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ω-3脂肪酸，具有抗炎作用。据报道，它可与G蛋白偶联受体120（GPR120）和GPR40结合。DHA可通过激活各种细胞中的泛素-蛋白酶体系统诱导某些蛋白质的降解。本研究旨在探讨DHA是否诱导Parkin并抑制vATPase活性，从而导致在蛙皮素（一种CCK类似物）刺激的胰腺腺泡AR42J细胞中酶原失活。
蛙皮素诱导vATPase的胞质V1结构域（E亚基）向膜的转位，这表明vATPase激活以及AR42J细胞中的酶原激活。DHA抑制了vATPase与膜的结合以及蛙皮素诱导的酶原激活（胰蛋白酶活性增加和淀粉酶释放）。用GPR120拮抗剂AH-7614、GPR40拮抗剂DC260126或泛素化抑制剂PYR-41预处理可降低DHA对蛙皮素诱导的酶原激活的作用。用PYR-41处理可逆转DHA诱导的蛙皮素处理细胞中vATPase激活的降低。此外，DHA增加了蛙皮素处理细胞的膜中Parkin的水平。
在蛙皮素刺激的胰腺腺泡细胞中，DHA通过GPR120和GPR40上调Parkin，从而抑制vATPase介导的酶原激活。
