title: Uncoupling protein 2 promoter polymorphism -866G/A affects its expression in beta-cells and modulates clinical profiles of Japanese type 2 diabetic patients.
abstract: Common uncoupling protein 2 (UCP2) promoter polymorphism -866G/A is reported to be associated with its expression in adipose tissue and the risk of obesity in Caucasians. On the other hand, several studies suggested that UCP2 expression in beta-cells is an important determinant of insulin secretion. In the Japanese population, morbid obesity is very rare, and insulin secretion capacity is relatively low as compared with Caucasians. Because UCP2 would link to insulin secretion and obesity, it might explain this ethnic difference. Here, we report that the UCP2 promoter with the A allele showed higher promoter activity in the INS-1 beta-cell line. The frequency of the A allele is higher in our Japanese study than that in Caucasians. Type 2 diabetic patients with the A allele need insulin therapy earlier and showed higher frequency of insulin treatment. Moreover glucose-induced early insulin secretion is significantly lower in patients with the A allele. However, there was no difference in allele frequency between obese and lean type 2 diabetic patients. In conclusion, UCP2 promoter polymorphism -866G/A does not affect obesity in Japanese type 2 diabetic patients but affects its transcription in beta-cells and modulates glucose-induced insulin secretion and eventually insulin requirement in Japanese type 2 diabetic patients. Higher A allele frequency in the Japanese population might partly explain the ethnic difference of insulin secretion capacity.
authors.affiliation: First Department of Medicine, Wakayama Medical University, Wakayama, Japan.
authors.forename: Miyoshi
authors.initials: M
authors.lastname: Sasahara
authors.forename: Masahiro
authors.initials: M
authors.lastname: Nishi
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Kawashima
authors.forename: Kazuya
authors.initials: K
authors.lastname: Ueda
authors.forename: Setsuya
authors.initials: S
authors.lastname: Sakagashira
authors.forename: Hiroto
authors.initials: H
authors.lastname: Furuta
authors.forename: Eisaku
authors.initials: E
authors.lastname: Matsumoto
authors.forename: Tadashi
authors.initials: T
authors.lastname: Hanabusa
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Sasaki
authors.forename: Kishio
authors.initials: K
authors.lastname: Nanjo
mesh_terms: D000368:Aged; D044466:Asian People; D001483:Base Sequence; D017931:DNA Primers; D003920:Diabetes Mellitus / Q000235:genetics; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics* / Q000473:pathology; D005260:Female; D005838:Genotype; D006801:Humans; D007473:Ion Channels; D007515:Islets of Langerhans / Q000473:pathology*; D007564:Japan; D008297:Male; D026901:Membrane Transport Proteins / Q000235:genetics*; D024101:Mitochondrial Proteins / Q000235:genetics*; D009765:Obesity; D020641:Polymorphism, Single Nucleotide; D012016:Reference Values; D000071246:Uncoupling Protein 2
chemical_list: D017931:DNA Primers; D007473:Ion Channels; D026901:Membrane Transport Proteins; D024101:Mitochondrial Proteins; C000604389:UCP2 protein, human; D000071246:Uncoupling Protein 2