TY - JOUR
T1 - O-GlcNAcylation of myocyte-specific enhancer factor 2D negatively regulates insulin secretion from pancreatic β-cells
AU - Yoshida, Mai
AU - Yokoi, Norihide
AU - Takahashi, Harumi
AU - Hatano, Naoya
AU - Hayami, Tomohide
AU - Ogawa, Wataru
AU - Seino, Susumu
N1 - Funding Information:
This study was supported by JSPS KAKENHI Grant Numbers JP18H02364 (N.Y.) and 21H02390 (N.Y.). The Division of Molecular and Metabolic Medicine is supported by MSD K.K., Novo Nordisk Pharma Ltd., Kowa Co. Ltd., and Taisho Pharmaceutical Holdings Co. Ltd.
Funding Information:
This study was supported by JSPS KAKENHI Grant Numbers JP18H02364 (N.Y.) and 21H02390 (N.Y.). The Division of Molecular and Metabolic Medicine is supported by MSD K.K. , Novo Nordisk Pharma Ltd ., Kowa Co. Ltd., and Taisho Pharmaceutical Holdings Co. Ltd.
Publisher Copyright:
© 2022 Elsevier Inc.
PY - 2022/5/21
Y1 - 2022/5/21
N2 - Patients with type 2 diabetes often exhibit impairments in both glucose-induced insulin secretion (GIIS) and incretin-induced insulin secretion (IIIS). These phenotypes are associated with altered glucose metabolism in pancreatic β-cells, although the molecular mechanisms remain unclear. Here, we used MIN6-K8 pancreatic β-cell lines as a model to examine the effect of O-linked N-acetylglucosamine glycosylation (O-GlcNAcylation), a glucose-induced protein posttranslational modification, on insulin secretion. O-GlcNAcylation was enhanced in high-glucose-treated MIN6-K8 cells, and high levels of O-GlcNAcylation attenuated PKA-dependent phosphorylation, suggesting that the two protein modifications may compete with each other. Immunoprecipitation proteomic analysis identified six candidate proteins that were O-GlcNAcylated by high-glucose treatment, whereas the O-GlcNAcylations were removed by treatment with an incretin mimetic, exendin-4. Among these proteins, knockdown of myocyte enhancer factor 2D (Mef2d) enhanced insulin secretion, and high-glucose treatment increased the level of O-GlcNAcylation of Mef2d in MIN6-K8 cells. Furthermore, knockout of Mef2d promoted GIIS in MIN6-K8 cells, whereas adenovirus-mediated rescue of Mef2d decreased GIIS in the knockout cells. These results suggest that Mef2d negatively regulates insulin secretion through O-GlcNAcylation.
AB - Patients with type 2 diabetes often exhibit impairments in both glucose-induced insulin secretion (GIIS) and incretin-induced insulin secretion (IIIS). These phenotypes are associated with altered glucose metabolism in pancreatic β-cells, although the molecular mechanisms remain unclear. Here, we used MIN6-K8 pancreatic β-cell lines as a model to examine the effect of O-linked N-acetylglucosamine glycosylation (O-GlcNAcylation), a glucose-induced protein posttranslational modification, on insulin secretion. O-GlcNAcylation was enhanced in high-glucose-treated MIN6-K8 cells, and high levels of O-GlcNAcylation attenuated PKA-dependent phosphorylation, suggesting that the two protein modifications may compete with each other. Immunoprecipitation proteomic analysis identified six candidate proteins that were O-GlcNAcylated by high-glucose treatment, whereas the O-GlcNAcylations were removed by treatment with an incretin mimetic, exendin-4. Among these proteins, knockdown of myocyte enhancer factor 2D (Mef2d) enhanced insulin secretion, and high-glucose treatment increased the level of O-GlcNAcylation of Mef2d in MIN6-K8 cells. Furthermore, knockout of Mef2d promoted GIIS in MIN6-K8 cells, whereas adenovirus-mediated rescue of Mef2d decreased GIIS in the knockout cells. These results suggest that Mef2d negatively regulates insulin secretion through O-GlcNAcylation.
KW - Diabetes
KW - Insulin secretion
KW - O-GlcNAcylation
KW - Pancreatic β cells
KW - PKA-Dependent phosphorylation
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U2 - 10.1016/j.bbrc.2022.03.036
DO - 10.1016/j.bbrc.2022.03.036
M3 - Article
C2 - 35316768
AN - SCOPUS:85126536712
VL - 605
SP - 90
EP - 96
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
SN - 0006-291X
ER -