Background: Micro (mi) RNAs have been found to play an important role in the regulation of adipogenesis and insulin sensitivity. However, associations between miRNA and insulin signalling-related gene expressions in abdominal adipose tissues in obese subjects remain unclear.
Methods: We used a microarray platform to screen miRNA expressions in abdominal adipose tissues between genders in severely obese subjects and found that the top-ranking miRNA in abdominal omental adipose tissues was miRNA-125a-3p. MicroR-125a-3p and insulin signalling-related gene expressions in abdominal omental adipose tissues of all subjects (11 men and 10 women) were subsequently quantified by a real-time PCR. Also, associations of miR-125a-3p with insulin signalling-related gene expression and biochemical markers in obese subjects were analyzed by a linear regression analysis.
Results: miR-125a-3p expressed by abdominal omental adipose tissues was much higher in obese men than women. No gender difference was observed in abdominal subcutaneous adipose tissues. Concomitant with high miR-125a-3p, c-Jun N-terminal kinase gene expression was also higher, whereas insulin receptor was lower in men than women. There were negative associations of miR-125a-3p with the insulin receptor and phosphatidylinositol 3-kinase expressions. Fasting plasma glucose and cholesterol levels were positively associated with miR- 125a-3p expression. These associations were obvious in obese men but not women.
Conclusion: Our results support the involvement of miR-125a-3p in regulating the insulin signalling pathway and imply that increased miR- 125a-3p expression in omental adipose tissues may be a characteristic feature of insulin resistance in obese men.
背景：微形核糖核酸(miRNA)在調節脂肪生合成及胰島素抗性扮演重要角色， 但是肥胖者腹腔脂肪組織miRNA 與胰島素訊息傳遞相關基因表現之間的相關 性仍不確知。方法: 本研究利用微陣列的平台來篩檢不同性別重度肥胖者腹腔 脂肪組織中miRNA 的表現，發現在腹腔網膜脂肪表現量最高的是miRNA- 125a-3p，所以我們再用即時聚合酶鏈鎖反應確認並定量所有肥胖者(11 位男性 及10 位女性)腹腔網膜脂肪中miRNA-125a-3p 及胰島素訊息傳遞相關基因的 表現，同時也以線性迴歸法分析miRNA-125a-3p 與胰島素訊息傳遞相關基因 表現及血中生化指標間的相關性。結果: 肥胖男性腹腔網膜脂肪miRNA-125a- 3p 的表現較女性為高，腹腔皮下脂肪則無性別間之差異，有高miRNA-125a- 3p 表現量的肥胖男性，其c-Jun N-terminal kinase 的基因表現量也會高，而胰 島素接受器的表現量則較肥胖女性為低。miRNA-125a-3p 與胰島素接受器及 phosphatidylinositol 3-kinase 的表現成負相關， 而空腹血糖和膽固醇值與 miRNA-125a-3p 的表現則成正相關。這些相關性在肥胖男性很顯著，但在肥胖 女性則不明顯。結論:本研究結果顯示miRNA-125a-3p 參與了胰島素訊息傳遞 路徑的調節，而腹腔網膜脂肪miRNA-125a-3p 表現量增加可能是肥胖男性胰 島素抗性的一個表徵。