Sphingosine 1-phosphate acts as an activator for the porcine Gpr3 of constitutively active G protein-coupled receptors

We cloned the complete coding sequences of porcine Gpr3,Gpr6,and Gpr12 genes.Further,on the basis of their high levels of sequence similarity,these genes are identified as a subfamily of G protein-coupled receptors.These putative protein sequences also showed high sequence identity with other mammalian orthologs,including several highly conserved motifs.A wide expression of the Gpr3 gene in pigs was observed through tissue distribution analysis by reverse transcriptase-polymerase chain reaction(RT-PCR)and real-time PCR,specially in the brain,pituitary,fat,liver and oocyte,where its strong expression was observed.The Gpr3 gene was found to be located on chromosome 6 and a single exon coded for the entire open-reading frame.Expression of porcine Gpr3 in HEK293 cells resulted in constitutive activation of adenylate cyclase(AC)similar in amplitude to that produced by fully stimulated Gs-coupled receptors.Moreover,sphingosine 1-phosphate(S1P)could increase AC activation via the constitutively active Gpr3 receptor.When a Gpr3-green fluorescent protein(GFP)construct was expressed in HEK293 cells,GFP-labeled Gpr3 protein was shown to be localized in the plasmalemma and subcellular membranes.After S1P treatment,agonist-mediated internalization could be visualized by confocal microscopy.In short,our findings suggest the porcine Gpr3,Gpr6,and Gpr12 genes as a subfamily of G protein-coupled receptors,and porcine Gpr3 was a constitutively active G protein-coupled receptor.Constitutive activation of AC and agonist-mediated internalization of Gpr3 receptor could be modulated by the S1P,suggesting that S1P might act as an activator for porcine Gpr3 receptor.

PPARγ2 functions as a tumor suppressor in a translational mouse model of human prostate cancer

Peroxisome proliferator-activated receptorsγ(PPARγ)is a master regulator that controls energy metabolism and cell fate.PPARγ2,a PPARγisoform,is highly expressed in the normal prostate but expressed at lower levels in prostate cancer tissues.In the present study,PC3 and LNCaP cells were used to examine the benefits of restoring PPARγ2 activity.PPARγ2 was overexpressed in PC3 and LNCaP cells,and cell proliferation and migration were detected.Hematoxylin and eosin(H&E)staining was used to detect pathological changes.The genes regulated by PPARγ2 overexpression were detected by microarray analysis.The restoration of PPARγ2 in PC3 and LNCaP cells inhibited cell proliferation and migration.PC3-PPARγ2 tissue recombinants showed necrosis in cancerous regions and leukocyte infiltration in the surrounding stroma by H&E staining.We found higher mixed lineage kinase domain-like(MLKL)and lower microtubule-associated protein 1 light chain 3(LC3)expression in cancer tissues compared to controls by immunohistochemistry(IHC)staining.Microarray analysis showed that PPARγ2 gain of function in PC3 cells resulted in the reprogramming of lipid-and energy metabolism-associated signaling pathways.These data indicate that PPARγ2 exerts a crucial tumor-suppressive effect by triggering necrosis and an inflammatory reaction in human prostate cancer.