MicroRNA-143 up-regulated in the adipose tissue of high-fat diet-induced obese mice
Rieko Takanabe1, Koh Ono2, Tomohide Takaya1, Takahiro Horie2, Hiromichi Wada1, Toru Kita2, Akira Shimatsu1, Koji Hasegawa1.
- Division of Translational Research, National Hospital Organization Kyoto Medical Center, Kyoto, Japan.
- Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
The 18th Great Wall International Congress of Cardiology (Beijing, China), 2007/10/11 (Poster).
Abstract
MicroRNAs (miRNAs) are approximately 17-24 nt single stranded RNA, that post-transcriptionally regulate gene expression. Recently, miRNAs has been proposed to play a role in the differentiation of preadipocytes into mature adipocytes in culture. Since changes in gene expression during adipocyte differentiation are closely associated with insulin resistance and cardiovascular diseases, we hypothesized that regulated expression of miRNAs in the adult adipose tissue play a pathophysiological role in obesity in vivo. C57BL/6 mice were fed with either high-fat diet or normal chow. Eight weeks later, severe obesity and insulin resistance was observed in mice on high-fat diet. We measured expression levels of miR-143 in mesenteric adipose tissue by real-time PCR. Expression of miR-143 was significantly up-regulated (3-fold) in the adipose tissue on high-fat diet compared to normal chow. One of miR-143 targets is ERK5/BMK1, activation of which has been proposed to inhibit inflammation as well as to promote cell proliferation. Western blot analysis demonstrated that expression of ERK5 in the mesenteric fat tissue was down-regulated by high-fat diet. These findings provide the first evidence for up-regulated expression of miR-143 in the adipose tissue of obese mice, which might contribute to inflammation and adipocyte hypertrophy through down-regulation of ERK5.