Metrnl：新的调节米色脂肪形成的细胞因子

Metrnl：a novel cytokine regulating beige fat formation

人脂肪组织一般分为白色脂肪组织（WAT）和棕色脂肪组织（BAT）两种.最近研究发现了一种特殊类型的脂肪,称之为＆quot;米色脂肪＆quot;.米色脂肪能燃烧储存的热量,减轻体重,改善糖、脂代谢,因此成为了最近研究的热点.然而,米色脂肪的形成机制一直不明确.最近有研究指出,小鼠运动后的肌肉组织和寒冷暴露后的脂肪组织中,可以产生一种细胞因子——meteorin-like（metrnl）,并能释放入血.Metrnl作用于嗜酸粒细胞,后者分泌白细胞介素（IL）-4/IL-13,进一步激活WAT中的M2型巨噬细胞,通过释放儿茶酚胺促进米色脂肪的形成.这些研究结果提示,metrnl是一新型的细胞因子,在活化米色脂肪中发挥重要作用,可能成为肥胖及相关代谢性疾病治疗的新靶点.

Generally, human adipose tissue is divided into white adipose tissue （WAT） and brown adipose tissue （BAT）.Recent studies have found there is a special type of fat named ＆quot;beige fat＆quot;.It has been demonstrated that beige fat can burn fat, reduce weight and modulate glucose lipid metabolism, thus it becomes a hot spot of recent studies.However, the formation mechanism of beige fat is not clear.Recent studies have identified a novel cytokine named meteorin-like （metrnl） , which can be induced in muscle after exercise and in adipose tissue upon cold exposure in mice.It has been reported that metrnl can activate eosinophils and promote the secretion of interleukin-4 and interleukin-13.These cytokines will further activate type 2 macrophages in white adipose tissue and increase the expression of tyrosine hydroxylase and the production of catecholamine, which then leads to the browning of adipose tissue.These results indicate that metrnl, as a novel cytokine, plays an important role in the activation of beige fat.It may become a new target for treatment of obesity and related metabolic diseases.