Department of Immunology , Center of Biostructure Research, Medical University of Warsaw , Warsaw , Poland ; Genomic Medicine, Department of General, Transplant and Liver Surgery , Medical University of Warsaw , Warsaw , Poland.
Department of Immunology , Center of Biostructure Research, Medical University of Warsaw , Warsaw , Poland.
BMJ Open Diabetes Res Care. 2014 Apr 26;2(1):e000017. doi: 10.1136/bmjdrc-2014-000017. eCollection 2014.
Considering the increasing number of clinical observations indicating hyperglycemic effects of statins, this study was designed to measure the influence of statins on the uptake of glucose analogs by human cells derived from liver, adipose tissue, and skeletal muscle.
Flow cytometry and scintillation counting were used to measure the uptake of fluorescently labeled or tritiated glucose analogs by differentiated visceral preadipocytes, skeletal muscle cells, skeletal muscle myoblasts, and contact-inhibited human hepatocellular carcinoma cells. A bioinformatics approach was used to predict the structure of human glucose transporter 1 (GLUT1) and to identify the presence of putative cholesterol-binding (cholesterol recognition/interaction amino acid consensus (CRAC)) motifs within this transporter. Mutagenesis of CRAC motifs in SLC2A1 gene and limited proteolysis of membrane GLUT1 were used to determine the molecular effects of statins.
Statins significantly inhibit the uptake of glucose analogs in all cell types. Similar effects are induced by methyl-β-cyclodextrin, which removes membrane cholesterol. Statin effects can be rescued by addition of mevalonic acid, or supplementation with exogenous cholesterol. Limited proteolysis of GLUT1 and mutagenesis of CRAC motifs revealed that statins induce conformational changes in GLUTs.
Statins impair glucose uptake by cells involved in regulation of glucose homeostasis by inducing cholesterol-dependent conformational changes in GLUTs. This molecular mechanism might explain hyperglycemic effects of statins observed in clinical trials.
鉴于越来越多的临床观察表明他汀类药物具有升高血糖的作用，本研究旨在测量他汀类药物对人源肝、脂肪组织和骨骼肌细胞摄取葡萄糖类似物的影响。
使用流式细胞术和闪烁计数法测量荧光标记或氚标记的葡萄糖类似物在分化的内脏前体脂肪细胞、骨骼肌细胞、骨骼肌成肌细胞和接触抑制的人肝癌细胞中的摄取情况。采用生物信息学方法预测人葡萄糖转运蛋白 1（GLUT1）的结构，并鉴定该转运蛋白中存在潜在的胆固醇结合（胆固醇识别/相互作用氨基酸共识（CRAC））基序。在 SLC2A1 基因中突变 CRAC 基序并对膜 GLUT1 进行有限水解，以确定他汀类药物的分子作用。
他汀类药物显著抑制所有细胞类型中葡萄糖类似物的摄取。甲基-β-环糊精也会诱导类似的作用，它可以去除膜胆固醇。添加甲羟戊酸或补充外源性胆固醇可以挽救他汀类药物的作用。GLUT1 的有限水解和 CRAC 基序的突变表明，他汀类药物通过诱导 GLUTs 的构象变化来抑制葡萄糖的摄取。
他汀类药物通过诱导 GLUTs 中的胆固醇依赖性构象变化，损害参与葡萄糖稳态调节的细胞对葡萄糖的摄取，从而导致高血糖。这种分子机制可能解释了临床试验中观察到的他汀类药物的升糖作用。
