目的研究固醇调节元件结合蛋白1c(sterol regulatory element binding protein 1c,SREBP1c)对肠道糖异生的调控作用。方法饥饿处理C57BL/6小鼠、SREBP1c纯合敲除型(SREBP1c-KO)和同窝野生型(SREBP1c-WT)小鼠,通过qPCR、Western blot检...目的研究固醇调节元件结合蛋白1c(sterol regulatory element binding protein 1c,SREBP1c)对肠道糖异生的调控作用。方法饥饿处理C57BL/6小鼠、SREBP1c纯合敲除型(SREBP1c-KO)和同窝野生型(SREBP1c-WT)小鼠,通过qPCR、Western blot检测糖异生途径限速酶葡萄糖-6-磷酸酶(glucose-6-phosphatase catalytic,G6PC)和磷酸烯醇式丙酮酸羧激酶(phosphoenolpyruvate carboxykinase 1,PCK1)在肝脏、空肠和回肠组织中的表达水平;在肠上皮细胞CaCo-2中过表达或敲低SREBP1c,检测细胞内G6PC和PCK1表达水平。结果饥饿处理后,C57BL/6小鼠空肠、回肠组织中G6PC、PCK1和SREBP1c表达水平均显著增加(P<0.05)。SREBP1c基因敲除后,小鼠空肠、回肠组织中由饥饿诱导的糖异生限速酶G6PC和PCK1的表达明显下调(P<0.05)。在肠上皮细胞CaCo-2中过表达SREBP1c,可显著上调糖异生途径关键酶G6PC和PCK1的表达,促进细胞内葡萄糖的产生(P<0.05);反之,敲低SREBP1c的表达,可明显下调G6PC和PCK1,抑制细胞内葡萄糖的产生(P<0.05)。结论饥饿状态下,SREBP1c可调控肠上皮细胞中糖异生限速酶G6PC和PCK1的表达,进而影响葡萄糖的生成,表明SREBP1c可能参与肠道糖异生的调控,机制有待进一步探索。展开更多
Glycogen storage disease type Ia(GSD-Ia)is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase-α(G6Pase-αor G6PC)that is expressed primarily in the liver,kidney,and intestine.G6...Glycogen storage disease type Ia(GSD-Ia)is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase-α(G6Pase-αor G6PC)that is expressed primarily in the liver,kidney,and intestine.G6Pase-αcatalyzes the hydrolysis of glucose-6-phosphate(G6P)to glucose and phosphate in the terminal step of gluconeogenesis and glycogenolysis,and is a key enzyme for endogenous glucose production.The active site of G6Pase-αis inside the endoplasmic reticulum(ER)lumen.For catalysis,the substrate G6P must be translocated from the cytoplasm into the ER lumen by a G6P transporter(G6PT).The functional coupling of G6Pase-αand G6PT maintains interprandial glucose homeostasis.Dietary therapies for GSD-Ia are available,but cannot prevent the long-term complication of hepatocellular adenoma that may undergo malignant transformation to hepatocellular carcinoma.Animal models of GSD-Ia are now available and are being exploited to both delineate the disease more precisely and develop new treatment approaches,including gene therapy.展开更多
文摘目的研究固醇调节元件结合蛋白1c(sterol regulatory element binding protein 1c,SREBP1c)对肠道糖异生的调控作用。方法饥饿处理C57BL/6小鼠、SREBP1c纯合敲除型(SREBP1c-KO)和同窝野生型(SREBP1c-WT)小鼠,通过qPCR、Western blot检测糖异生途径限速酶葡萄糖-6-磷酸酶(glucose-6-phosphatase catalytic,G6PC)和磷酸烯醇式丙酮酸羧激酶(phosphoenolpyruvate carboxykinase 1,PCK1)在肝脏、空肠和回肠组织中的表达水平;在肠上皮细胞CaCo-2中过表达或敲低SREBP1c,检测细胞内G6PC和PCK1表达水平。结果饥饿处理后,C57BL/6小鼠空肠、回肠组织中G6PC、PCK1和SREBP1c表达水平均显著增加(P<0.05)。SREBP1c基因敲除后,小鼠空肠、回肠组织中由饥饿诱导的糖异生限速酶G6PC和PCK1的表达明显下调(P<0.05)。在肠上皮细胞CaCo-2中过表达SREBP1c,可显著上调糖异生途径关键酶G6PC和PCK1的表达,促进细胞内葡萄糖的产生(P<0.05);反之,敲低SREBP1c的表达,可明显下调G6PC和PCK1,抑制细胞内葡萄糖的产生(P<0.05)。结论饥饿状态下,SREBP1c可调控肠上皮细胞中糖异生限速酶G6PC和PCK1的表达,进而影响葡萄糖的生成,表明SREBP1c可能参与肠道糖异生的调控,机制有待进一步探索。
基金This research was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development,National Institutes of Health(HD000912-38).
文摘Glycogen storage disease type Ia(GSD-Ia)is an autosomal recessive metabolic disorder caused by a deficiency in glucose-6-phosphatase-α(G6Pase-αor G6PC)that is expressed primarily in the liver,kidney,and intestine.G6Pase-αcatalyzes the hydrolysis of glucose-6-phosphate(G6P)to glucose and phosphate in the terminal step of gluconeogenesis and glycogenolysis,and is a key enzyme for endogenous glucose production.The active site of G6Pase-αis inside the endoplasmic reticulum(ER)lumen.For catalysis,the substrate G6P must be translocated from the cytoplasm into the ER lumen by a G6P transporter(G6PT).The functional coupling of G6Pase-αand G6PT maintains interprandial glucose homeostasis.Dietary therapies for GSD-Ia are available,but cannot prevent the long-term complication of hepatocellular adenoma that may undergo malignant transformation to hepatocellular carcinoma.Animal models of GSD-Ia are now available and are being exploited to both delineate the disease more precisely and develop new treatment approaches,including gene therapy.
