Popov Violeta B, Jornayvaz Francois R, Akgul Emin O, Kanda Shoichi, Jurczak Michael J, Zhang Dongyan, Abudukadier Abulizi, Majumdar Sachin K, Guigni Blas, Petersen Kitt Falk, Manchem Vara Prasad, Bhanot Sanjay, Shulman Gerald I, Samuel Varman T
*Department of Internal Medicine, Department of Cellular and Molecular Physiology, and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA; West Haven Veterans Affairs Medical Center, West Haven, Connecticut, USA; and ISIS Pharmaceuticals, Carlsbad, California, USA.
*Department of Internal Medicine, Department of Cellular and Molecular Physiology, and Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut, USA; West Haven Veterans Affairs Medical Center, West Haven, Connecticut, USA; and ISIS Pharmaceuticals, Carlsbad, California, USA
FASEB J. 2016 Mar;30(3):1207-17. doi: 10.1096/fj.15-271999. Epub 2015 Dec 7.
Although mutations in the Wnt/β-catenin signaling pathway are linked with the metabolic syndrome and type 2 diabetes in humans, the mechanism is unclear. High-fat-fed male C57BL/6 mice were treated for 4 wk with a 2'-O-methoxyethyl chimeric antisense oligonucleotide (ASO) to decrease hepatic and adipose expression of β-catenin. β-Catenin mRNA decreased by ≈80% in the liver and by 70% in white adipose tissue relative to control ASO-treated mice. β-Catenin ASO improved hepatic insulin sensitivity and increased insulin-stimulated whole body glucose metabolism, as assessed during hyperinsulinemic-euglycemic clamp in awake mice. β-Catenin ASO altered hepatic lipid composition in high-fat-fed mice. There were reductions in hepatic triglyceride (44%, P < 0.05) and diacylglycerol content (60%, P < 0.01) but a 30% increase in ceramide content (P < 0.001). The altered lipid content was attributed to decreased expression of sn-1,2 diacylglycerol acyltransferase and mitochondrial acyl-CoA:glycerol-sn-3-phosphate acyltransferase and an increase in serine palmitoyl transferase. The decrease in cellular diacyglycerol was associated with a 33% decrease in PKCε activation (P < 0.05) and 64% increase in Akt2 phosphorylation (P < 0.05). In summary, Reducing β-catenin expression decreases expression of enzymes involved in hepatic fatty acid esterification, ameliorates hepatic steatosis and lipid-induced insulin resistance.
虽然Wnt/β-连环蛋白信号通路的突变与人类的代谢综合征和2型糖尿病有关,但其机制尚不清楚。用2'-O-甲氧基乙基嵌合反义寡核苷酸(ASO)对高脂喂养的雄性C57BL/6小鼠进行4周治疗,以降低肝脏和脂肪组织中β-连环蛋白的表达。相对于对照ASO处理的小鼠,肝脏中β-连环蛋白mRNA减少约80%,白色脂肪组织中减少70%。如在清醒小鼠的高胰岛素-正常血糖钳夹期间所评估的,β-连环蛋白ASO改善了肝脏胰岛素敏感性并增加了胰岛素刺激的全身葡萄糖代谢。β-连环蛋白ASO改变了高脂喂养小鼠的肝脏脂质组成。肝脏甘油三酯(44%,P<0.05)和二酰基甘油含量(60%,P<0.01)降低,但神经酰胺含量增加30%(P<0.001)。脂质含量的改变归因于sn-1,2二酰基甘油酰基转移酶和线粒体酰基辅酶A:甘油-sn-3-磷酸酰基转移酶的表达降低以及丝氨酸棕榈酰转移酶的增加。细胞二酰基甘油的减少与PKCε活化降低33%(P<0.05)和Akt2磷酸化增加64%(P<0.05)相关。总之,降低β-连环蛋白表达可降低参与肝脏脂肪酸酯化的酶的表达,改善肝脏脂肪变性和脂质诱导的胰岛素抵抗。