高碳水化合物条件下鼠肌GLUT4表达与CaMK/HDAC5关系的研究

Relationship between GLUT4 Expression and CaMK/HDAC5 in Rat Skeletal Muscle under Different Carbohydrates

观察Caffeine诱导骨骼肌细胞GLUT4表达的潜在分子调控机制是否是Caffeine-Ca2+-CaMKⅡ-HDAC5信号通路。8周龄雄性Wistar大鼠42只,随机分为高碳Caffeine组(HGC)、高碳KN62组(HGK)、低碳Caffeine组(LGC)和低碳KN62组(LGK),每组12只。分别给予不同饮食加Caffeine或KN62刺激。检测CaMKⅡ(Thr286)位点、HDAC5(Ser498)位点和HDAC5(Ser259)位点磷酸化水平以及GLUT4蛋白表达水平。与HGC组相比LGC组GLUT4蛋白表达、CaMKⅡ(Thr286)、HDAC5(Ser498)HDAC5(Ser259)磷酸化水平都显著增加性高于HGC组和LGK组。无论是在低碳还是在高碳浓度下骨骼肌细胞GLUT4蛋白表达变化都对应着上游CaMKⅡ蛋白位点(Thr286)磷酸化水平和下游HDAC5蛋白位点(Ser498)和(Ser259)磷酸化的变化,所以CaMKⅡ调节GLUT4表达的机制至少涉及到CaMKⅡ征用转录抑制子HDAC5。

To find out whether the effect of Caffeine on regulating the GLUT4 expression was related with Caffeine-Ca2 ＋ - CaMK Ⅱ -HDAC5 signal pathway. 48 male Wistar rats which were 8-week-old were randomly divided into four groups （ n = 12）, named as HGC group, HGK group, LGC group and LGK group. The rats were fed with different diet and induced by Caffeine or KN62. And CaMK Ⅱ （ Thr286 ）, HDAC5 （ Ser498 ） and HDAC5 （Ser＇259）phosphorylation and GLUT4 protein expression were tested by western blotting. Compared with the LGK group, both CaMK Ⅱ （ Thr286 ） and HDAC5 （Ser259） and ItDAC5 （Ser498） phosphorylatlon increased significantly in skeletal muscle cells in LGC group. Compared with the LGK and LGC group, CaMK Ⅱ （ Thr286 ） ,HDAC5 （ Ser498 ） and HDAC5 （ Ser259 ） phosphorylation decreased obviously in HGC and HGK group. Meanwhile, the changes of CaMK Ⅱ （ Thr286 ） ,HDAC5 （ Ser498 ） and HDAC5 （ Ser：259 ） phosphorylation in HGC group had no significant difference with that in HGK group. Therefore （1） Caffeine could remarkably increase the expression of GLUT4, and increase the CaMK Ⅱ （Thr286） ,HDAC5 （ Ser498 ） and HDAC5 （ Ser259 ） phosphorylation and exist a remarkably positive correlation. While KN62 could significantly decrease the CaMK Ⅱ （Thr286） ,HDAC5 （Ser498） and HDAC5 （Ser259）phosphorylation and the expression GLUT4. They demonstrated that the effect of Ca2 ＊ signal which was induced by Caffeine on increasing the expression of GLUT4 was possibly related with Caffeine-Ca2 ＋ - CaMK Ⅱ -HDAC5 signal pathway. （ 2 ） Whatever the rats were fed with, the expression of GLUT4 was corresponded with CaMK Ⅱ （ Thr286 ） ,HDAC5 （ Ser498 ） and HDAC5 （ Ser259 ） in skeletal muscle cells. So the effect of CaMK lI on regulating the expression of GLUT4 in skeletal muscle was related with inducing HDAC5 and regulating its （ Ser 498 ） site and（ Ser 259 ） site.