Aims/hypothesis Amylin, a secretory protein mainly produced by pancreatic beta cells, is elevated in the circulation of patients with diseases related to acute and chronic inflammation, including acute pancreatitis, pancreas graft rejection, obesity and insulin resistance. TNF-α is involved in these disorders. We investigated the effect of TNF-α on amylin levels and the underlying mechanisms, using murine pancreatic beta cell line MIN6 and pancreatic islets. Methods Amylin, proinsulin and prohormone convertase 1/3, 2 (Pc1/3, Pc2 [also known as Pcsk1/3 and Pcsk2, respectively]) mRNA levels, and amylin promoter and nuclear factor κB (NF-κB) activation were examined by real-time PCR and luciferase reporter assay, respectively. Amylin protein level and mitogen-activated protein kinase phosphorylation were detected by western blot. Activator protein 1 (AP1) activation was examined by electrophoretic mobility shift assay (EMSA).Results TNF-α acutely induced amylin expression at the transcriptional level and increased proamylin and the intermediate form of amylin in MIN6 cells and islets. However, it had no effect on proinsulin, Pc1/3 and Pc2 expression. Studies with (1) MIN6 cells treated with inhibitors of MEK1/2, c-Jun-N-terminal kinase (JNK) or protein kinase CK PKC ð z Þ, (2) MIN6 cells expressing a c-Jun-dominant negative construct and (3) islets from Fos knockout mice demonstrated that TNF-α induced amylin expression through the PKC z Àextracellular signal-regulated kinase (ERK)/JNK pathways. EMSA showed that PKC z , JNK and ERK1/2 were involved in TNF-α-induced AP1 activation, suggesting that TNF-α induces murine amylin expression through the PKC z ÀERK1=2ÀAP1 and PKC z À JNKÀAP1 pathways. Further studies showed that TNF-α also induced murine amylin expression through the phosphatidylinositol 3 kinase-NF-κB signalling pathway and enhanced human amylin promoter activation through NF-κB and AP1. Conclusions/interpretation TNF-α acutely induces amylin gene expression in beta cells through multiple signalling pathways, possibly contributing to amylin elevation in acute inflammation-related pancreatic disorders.
The solvothermal reaction of 4,4′-bipyridine (Bipy) and mercury nitrate in a mixed acetonitrile/water solution leads to a novel mercury coordination compound with the in situ formation of cyanide ions Hg(Bipy)(CN) 2 (1). Its structure is determined by single crystal X-ray diffraction (XRD), and further characterized by powder XRD, elemental analysis, and IR spectroscopy. Compound 1 exhibits a 1D zigzag [Hg(Bipy)(CN) 2 ] n chain structure. The solid-state photoluminescent properties of 1 are also investigated.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.