Mechanisms of glucose-induced expression of pancreatic-derived factor in pancreatic beta-cells.
Pancreatic-derived factor (PANDER) is a cytokine-like peptide highly expressed in pancreatic beta-cells. PANDER was reported to promote apoptosis of pancreatic beta-cells and secrete in response to glucose. Here we explored the effects of glucose on PANDER expression, and the underlying mechanisms in murine pancreatic beta-cell line MIN6 and primary islets. Our results showed that glucose up-regulated PANDER mRNA and protein levels in a time- and dose-dependent manner in MIN6 cells and pancreatic islets. In cells expressing cAMP response element-binding protein (CREB) dominant-negative construct, glucose failed to induce PANDER gene expression and promoter activation. Treatment of the cells with calcium chelator [EGTA, 1,2-bis(o-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetra(acetoxymethyl)ester (BAPTA/AM)], the voltage-dependent Ca(2+) channel inhibitor (nifedipine), the protein kinase A (PKA) inhibitor (H89), the protein kinase C (PKC) inhibitor (Go6976), or the MAPK kinase 1/2 inhibitor (PD98059), all significantly inhibited glucose-induced PANDER gene expression and promoter activation. Further studies showed that glucose induced CREB phosphorylation through Ca(2+)-PKA-ERK1/2 and Ca(2+)-PKC pathways. Thus, the Ca(2+)-PKA-ERK1/2-CREB and Ca(2+)-PKC-CREB signaling pathways are involved in glucose-induced PANDER gene expression. Wortmannin (phosphatidylinositol 3-kinase inhibitor), ammonium pyrrolidinedithiocarbamate (nuclear factor-kappaB inhibitor and nonspecific antioxidant), and N-acetylcysteine (antioxidant) were also found to inhibit glucose-induced PANDER promoter activation and gene expression. Because there is no nuclear factor-kappaB binding site in the promoter region of PANDER gene, these results suggest that phosphatidylinositol 3-kinase and reactive oxygen species be involved in glucose-induced PANDER gene expression. In conclusion, glucose induces PANDER gene expression in pancreatic beta-cells through multiple signaling pathways. Because PANDER is expressed by pancreatic beta-cells and in response to glucose in a similar way to those of insulin, PANDER may be involved in glucose homeostasis.
Wang
Oumei
O
Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, PR China.
Cai
Kun
K
Pang
Shanshan
S
Wang
Ting
T
Qi
Dongfei
D
Zhu
Quanfeng
Q
Ni
Zimei
Z
Le
Yingying
Y
D000818:Animals; D002460:Cell Line; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D016207:Cytokines / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression / Q000187:drug effects / Q000502:physiology; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D050417:Insulin-Secreting Cells / Q000166:cytology / Q000502:physiology*; D008156:Luciferases / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000502:physiology; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection
C492004:Creb1 protein, mouse; D017362:Cyclic AMP Response Element-Binding Protein; D016207:Cytokines; C504749:PANDER protein, mouse; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D008156:Luciferases; D019869:Phosphatidylinositol 3-Kinases; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D005947:Glucose