Positive regulation by GABAbR1 subunit of leptin expression through gene transactivation in adipocytes

Yukari Nakamura, Eiichi Hinoi, Takeshi Takarada, Yoshifumi Takahata, Tomomi Yamamoto, Hiroyuki Fujita, Saya Takada, Syota Hashizume, Yukio Yoneda

研究成果: ジャーナルへの寄稿学術誌査読

17 被引用数 (Scopus)


Background: The view that γ-aminobutyric acid (GABA) plays a functional role in non-neuronal tissues, in addition to an inhibitory neurotransmitter role in the mammalian central nervous system, is prevailing, while little attention has been paid to GABAergic signaling machineries expressed by adipocytes to date. In this study, we attempted to demonstrate the possible functional expression of GABAergic signaling machineries by adipocytes. Methodology/Principal Findings: GABAB receptor 1 (GABABR1) subunit was constitutively expressed by mouse embryonic fibroblasts differentiated into adipocytes and adipocytic 3T3-L1 cells in culture, as well as mouse white adipose tissue, with no responsiveness to GABABR ligands. However, no prominent expression was seen with mRNA for GABABR2 subunit required for heteromeric orchestration of the functional GABABR by any adipocytic cells and tissues. Leptin mRNA expression was significantly and selectively decreased in adipose tissue and embryonic fibroblasts, along with drastically reduced plasma leptin levels, in GABABR1-null mice than in wild-type mice. Knockdown by siRNA of GABABR1 subunit led to significant decreases in leptin promoter activity and leptin mRNA levels in 3T3-L1 cells. Conclusions/Significance: Our results indicate that GABABR1 subunit is constitutively expressed by adipocytes to primarily regulate leptin expression at the transcriptional level through a mechanism not relevant to the function as a partner of heterodimeric assembly to the functional GABABR.

ジャーナルPloS one
出版ステータス出版済み - 2011

!!!All Science Journal Classification (ASJC) codes

  • 生化学、遺伝学、分子生物学(全般)
  • 農業および生物科学(全般)
  • 一般


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