Chronic ethanol consumption-induced pancreatic β dysfunction and apoptosis through glucokinase nitration and its down-regulation

Ji Yeon Kim, Eun Hyun Song, Hyun Jung Lee, Yeo Kyoung Oh, Yoon Shin Park, Joo Won Park, Bong Jo Kim, Dae Jin Kim, Inkyu Lee, Jihyun Song, Won Ho Kim

Research output: Contribution to journalArticlepeer-review

64 Scopus citations

Abstract

Chronic ethanol consumption is known as an independent risk factor for type 2 diabetes, which is characterized by impaired glucose homeostasis and insulin resistance; however, there is a great deal of controversy concerning the relationships between alcohol consumption and the development of type 2 diabetes. We investigated the effects of chronic ethanol consumption on pancreatic β-cell dysfunction and whether generated peroxynitrite participates in the impaired glucose homeostasis. Here we show that chronic ethanol feeding decreases the ability of pancreatic β-cells to mediate insulin secretion and ATP production in coordination with the decrease of glucokinase, Glut2, and insulin expression. Specific blockade of ATF3 using siRNA or C-terminally deleted ATF3(ΔC) attenuated ethanol-induced pancreatic β-cell apoptosis or dysfunction and restored the down-regulation of glucokinase (GCK), insulin, and pancreatic duodenal homeobox-1 induced by ethanol. GCK inactivation and down-regulation were predominantly mediated by ethanol metabolism-generated peroxynitrite, which were suppressed by the peroxynitrite scavengers Nγ-monomethyl-L-arginine, uric acid, and deferoxamine but not by the S-nitrosylation inhibitor DTT, indicating that tyrosine nitration is the predominant modification associated with GCK down-regulation and inactivation rather than S-nitrosylation of cysteine. Tyrosine nitration of GCK prevented its association with pBad, and GCK translocation into the mitochondria results in subsequent proteasomal degradation of GCK following ubiquitination. This study identified a novel and efficient pathway by which chronic ethanol consumption may induce GCK down-regulation and inactivation by inducing tyrosine nitration of GCK, resulting in pancreatic β-cell apoptosis and dysfunction. Peroxynitrite-induced ATF3 may also serve as a potent upstream regulator of GCK down-regulation and β-cell apoptosis.

Original languageEnglish
Pages (from-to)37251-37262
Number of pages12
JournalJournal of Biological Chemistry
Volume285
Issue number48
DOIs
StatePublished - 26 Nov 2010

Fingerprint

Dive into the research topics of 'Chronic ethanol consumption-induced pancreatic β dysfunction and apoptosis through glucokinase nitration and its down-regulation'. Together they form a unique fingerprint.

Cite this