Myricetin Protects Against High Glucose-Induced β-Cell Apoptosis by Attenuating Endoplasmic Reticulum Stress via Inactivation of Cyclin-Dependent Kinase 5
- Author:
Udayakumar KARUNAKARAN
1
;
Suma ELUMALAI
;
Jun Sung MOON
;
Jae Han JEON
;
Nam Doo KIM
;
Keun Gyu PARK
;
Kyu Chang WON
;
Jaechan LEEM
;
In Kyu LEE
Author Information
- Publication Type:Original Article
- Keywords: Apoptosis; Cyclin-dependent kinase 5; Endoplasmic reticulum stress; Insulin-secreting cells; Myricetin
- MeSH: Animals; Apoptosis; Blotting, Western; Calcium-Transporting ATPases; Cyclin-Dependent Kinase 5; Diabetes Mellitus, Type 2; Down-Regulation; Endoplasmic Reticulum Stress; Endoplasmic Reticulum; Gene Expression; Genes, Homeobox; Glucose; Hyperglycemia; Insulin-Secreting Cells; Membrane Potential, Mitochondrial; Polymerase Chain Reaction; Rats; Reactive Oxygen Species; Reticulum; Reverse Transcription; Up-Regulation
- From:Diabetes & Metabolism Journal 2019;43(2):192-205
- CountryRepublic of Korea
- Language:English
- Abstract: BACKGROUND: Chronic hyperglycemia has deleterious effects on pancreatic β-cell function and turnover. Recent studies support the view that cyclin-dependent kinase 5 (CDK5) plays a role in β-cell failure under hyperglycemic conditions. However, little is known about how CDK5 impair β-cell function. Myricetin, a natural flavonoid, has therapeutic potential for the treatment of type 2 diabetes mellitus. In this study, we examined the effect of myricetin on high glucose (HG)-induced β-cell apoptosis and explored the relationship between myricetin and CDK5. METHODS: To address this question, we subjected INS-1 cells and isolated rat islets to HG conditions (30 mM) in the presence or absence of myricetin. Docking studies were conducted to validate the interaction between myricetin and CDK5. Gene expression and protein levels of endoplasmic reticulum (ER) stress markers were measured by real-time reverse transcription polymerase chain reaction and Western blot analysis. RESULTS: Activation of CDK5 in response to HG coupled with the induction of ER stress via the down regulation of sarcoendoplasmic reticulum calcium ATPase 2b (SERCA2b) gene expression and reduced the nuclear accumulation of pancreatic duodenal homeobox 1 (PDX1) leads to β-cell apoptosis. Docking study predicts that myricetin inhibit CDK5 activation by direct binding in the ATP-binding pocket. Myricetin counteracted the decrease in the levels of PDX1 and SERCA2b by HG. Moreover, myricetin attenuated HG-induced apoptosis in INS-1 cells and rat islets and reduce the mitochondrial dysfunction by decreasing reactive oxygen species production and mitochondrial membrane potential (Δψm) loss. CONCLUSION: Myricetin protects the β-cells against HG-induced apoptosis by inhibiting ER stress, possibly through inactivation of CDK5 and consequent upregulation of PDX1 and SERCA2b.
