Dong Xiaoying, Tang Shengqiu, Zhang Wei, Gao Weihua, Chen Yanfei
a College of Yingdong Agricultural Science and Engineering, Shaoguan University , Shaoguan , P.R. China .
b Hubei Key Laboratory of Animal Embryo and Molecular Breeding, Hubei Academy of Agricultural Science , Wuhan , P.R. China .
J Recept Signal Transduct Res. 2016;36(2):130-8. doi: 10.3109/10799893.2015.1056308. Epub 2015 Nov 2.
The orphan G protein-coupled receptor (GPR) 39 was originally identified as the receptor of obestatin. In this study, the effects and mechanisms of GPR39 on cell proliferation and differentiation were investigated in cultured porcine intramuscular preadipocytes.
Morphology of preadipocytes and accumulated lipid droplets within cells were identified by an inverted microscope. After transfected with constructed pCMV-GPR39 plasmid, cell proliferation was measured by using methyl thiazolyl tetrazolium method, mRNA expression of GPR39, CCAAT/enhancer binding protein-α (C/EBPα), peroxisome proliferator-activated receptor-γ (PPARγ), Caspase-9 and adipocyte determination and differentiation factor-1 (ADD1) was determined by RNA preparation and reverse transcription polymerase chain reaction, protein expression of phosphoinositide-3 kinase (PI3K), 3-phosphoinositide-dependent protein kinase 1, phosphorylated glycogen synthase kinase 3 (pGSK3), total Akt and phosphorylated Akt (pAkt) was analyzed by Western blot.
It found that GPR39 mRNA and protein were expressed in porcine intramuscular preadipocytes and its expression was significantly up-regulated after treatment with Zn(2+) whose function is found to be mediated by GPR39. Furthermore, over-expression of GPR39 further promoted the optical density value of cells, enhanced mRNA expression of PPARγ, C/EBPα and ADD1, and inhibited mRNA expression of Caspase-9. Protein expression of pGSK3 and pAkt was also increased by GPR39 stimulation. In addition, GPR39-induced proliferation and differentiation of porcine intramuscular preadipocytes was partially blocked by the Akt inhibitor (PDTC) and the PI3K inhibitor (LY294002).
It indicated that GPR39 was a transducer of Zn(2+), and enhanced proliferation and differentiation of porcine intramuscular preadipocytes through activation of the PI3K/Akt signaling pathway.
孤儿G蛋白偶联受体（GPR）39最初被鉴定为肥胖抑制素的受体。在本研究中，我们在培养的猪肌内前体脂肪细胞中研究了GPR39对细胞增殖和分化的影响及其机制。
通过倒置显微镜观察前体脂肪细胞的形态以及细胞内积累的脂滴。用构建的pCMV - GPR39质粒转染细胞后，采用甲基噻唑基四氮唑法检测细胞增殖，通过RNA提取和逆转录聚合酶链反应测定GPR39、CCAAT/增强子结合蛋白α（C/EBPα）、过氧化物酶体增殖物激活受体γ（PPARγ）、半胱天冬酶 - 9（Caspase - 9）和脂肪细胞决定和分化因子 - 1（ADD1）的mRNA表达，通过蛋白质印迹分析磷酸肌醇 - 3激酶（PI3K）、3 - 磷酸肌醇依赖性蛋白激酶1、磷酸化糖原合酶激酶3（pGSK3）、总Akt和磷酸化Akt（pAkt）的蛋白表达。
发现GPR39 mRNA和蛋白在猪肌内前体脂肪细胞中表达，在用锌离子（Zn(2+)）处理后其表达显著上调，且发现锌离子的作用是由GPR39介导的。此外，GPR39的过表达进一步提高了细胞的光密度值，增强了PPARγ、C/EBPα和ADD1的mRNA表达，并抑制了Caspase - 9的mRNA表达。GPR39刺激还增加了pGSK3和pAkt的蛋白表达。此外，Akt抑制剂（PDTC）和PI3K抑制剂（LY294002）部分阻断了GPR39诱导的猪肌内前体脂肪细胞的增殖和分化。
表明GPR39是锌离子的转导分子，并通过激活PI3K/Akt信号通路增强猪肌内前体脂肪细胞的增殖和分化。
