Transcriptional regulation of an insulin-sensitizing adipokine adipolin/CTRP12 in adipocytes by Krüppel-like factor 15

PLoS One. 2013 Dec 16;8(12):e83183. doi: 10.1371/journal.pone.0083183. eCollection 2013.

Abstract

Obese states characterized by chronic inflammation are closely linked to the development of metabolic dysfunction. We identified adipolin/CTRP12 as an insulin-sensitizing and anti-inflammatory adipokine. Although obese conditions down-regulate adipolin expression, its molecular mechanism is largely unknown. Here we show that the transcriptional regulator Krüppel-like factor (KLF) 15 is involved in the regulation of adipolin expression in adipocytes. White adipose tissue from diet-induced obese (DIO) mice showed decreased expression of KLF9 and KLF15 among several KLFs, which was accompanied by reduced expression of adipolin. In cultured 3T3L1 adipocytes, treatment with TNFα significantly reduced the mRNA levels of KLF9, KLF15 and adipolin. Adenovirus-mediated overexpression of KLF15 but not KLF9 reversed TNFα-induced reduction of adipolin expression in adipocytes. Conversely, gene targeting ablation of KLF15 attenuated adipolin expression in adipocytes. Expression of KLF15 but not KLF9 enhanced the promoter activity of adipolin in HEK293 cells. Pretreatment of 3T3L1 adipocytes with the JNK inhibitor SP600125, but not p38 MAPK inhibitor SB203580 blocked the inhibitory effects of TNFα on adipolin and KLF15 expression. These data suggest that adipose inflammation under conditions of obesity suppresses adipolin expression via JNK-dependent down-regulation of KLF15 in adipocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3T3-L1 Cells
  • Adipocytes / drug effects
  • Adipocytes / metabolism*
  • Adipokines / genetics*
  • Adipokines / metabolism
  • Animals
  • DNA-Binding Proteins / physiology*
  • Gene Expression Regulation* / drug effects
  • HEK293 Cells
  • Humans
  • Kruppel-Like Transcription Factors
  • Mice
  • Mice, Inbred C57BL
  • Obesity / genetics
  • Obesity / metabolism
  • Transcription Factors / physiology*
  • Transcription, Genetic / drug effects
  • Tumor Necrosis Factor-alpha / pharmacology

Substances

  • Adipokines
  • C1qtnf12 protein, mouse
  • DNA-Binding Proteins
  • Klf15 protein, mouse
  • Kruppel-Like Transcription Factors
  • Transcription Factors
  • Tumor Necrosis Factor-alpha

Grants and funding

This work was supported by Grant-in-Aid for Scientific Research, Grant-in-Aid for Challenging Exploratory Research and grants from Takeda Science Foundation, the Uehara Memorial Foundation, Daiichi-Sankyo Foundation of Life Science, and SENSHIN Medical Research Foundation to N. Ouchi. R. Shibata was supported with the Grant-in-Aid for Young Scientists B and the Uehara Memorial Foundation. K. Ohashi was supported with the Grant-in-Aid for Scientific Research and The Cardiovascular Research Fund, Tokyo, Japan. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.