| Autor: |
Tomoko Okuyama, Jun Shirakawa, Hiromi Yanagisawa, Mayu Kyohara, Shunsuke Yamazaki, Kazuki Tajima, Yu Togashi, Yasuo Terauchi |
| Jazyk: |
angličtina |
| Rok vydání: |
2017 |
| Předmět: |
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| Zdroj: |
Scientific Reports, Vol 7, Iss 1, Pp 1-12 (2017) |
| Druh dokumentu: |
article |
| ISSN: |
2045-2322 |
| DOI: |
10.1038/s41598-017-02535-0 |
| Popis: |
Abstract Glucokinase-mediated glucose signaling induces insulin secretion, proliferation, and apoptosis in pancreatic β-cells. However, the precise molecular mechanisms underlying these processes are not clearly understood. Here, we demonstrated that glucokinase activation using a glucokinase activator (GKA) significantly upregulated the expression of Fibulin-5 (Fbln5), a matricellular protein involved in matrix-cell signaling, in isolated mouse islets. The islet Fbln5 expression was induced by ambient glucose in a time- and dose-dependent manner and further enhanced by high-fat diet or the deletion of insulin receptor substrate 2 (IRS-2), whereas the GKA-induced increase in Fbln5 expression was diminished in Irs-2-deficient islets. GKA-induced Fbln5 upregulation in the islets was blunted by a glucokinase inhibitor, KATP channel opener, Ca2+ channel blocker and calcineurin inhibitor, while it was augmented by harmine, a dual-specificity tyrosine phosphorylation-regulated kinase (DYRK) 1 A inhibitor. Although deletion of Fbln5 in mice had no significant effects on the glucose tolerance or β-cell functions, adenovirus-mediated Fbln5 overexpression increased glucose-stimulated insulin secretion in INS-1 rat insulinoma cells. Since the islet Fbln5 expression is regulated through a glucokinase/KATP channel/calcineurin/nuclear factor of activated T cells (NFAT) pathway crucial for the maintenance of β-cell functions, further investigation of Fbln5 functions in the islets is warranted. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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