Laboratory of Pharmacobiology and Therapeutics, Faculty of Pharmacy, Meijo University, 150 Yagotoyama, Tenpaku-ku, Nagoya 468-8503, Japan.
Eur J Pharmacol. 2011 Dec 15;672(1-3):159-68. doi: 10.1016/j.ejphar.2011.09.185. Epub 2011 Oct 2.
Hyperglycemia and hyperlipidemia are considered critical to the development of diabetic nephropathy. The aim of this study is to clarify the effect of cholesterol on advanced-glycation-end-products and the mechanisms behind the advanced-glycation-end-product-cholesterol-aggregated bovine serum albumin (BSA)-induced proliferation of mesangial cells. Mesangial cells were treated with advanced-glycation-end-product-cholesterol-aggregated-BSA, and RNA and protein were isolated. Cholesterol caused a 1.5-fold increase in fluorescent intensity and 2-fold increase in advanced-glycation-end-products in vitro. Pyridoxamine, aminoguanidine, and N-acetyl-l-cycteine suppressed the production of advanced-glycation-end-product-cholesterol-aggregated-BSA. Advanced-glycation-end-product-cholesterol-BSA was analyzed by matrix-assisted-laser-desorption/ionization-time of flight mass spectrometry, and peaks were found to shift toward a higher mass. Advanced-glycation-end-product-cholesterol-aggregated-BSA induced overexpression of the mRNA of transforming growth factor-beta1, collagen type 1, collagen type 4 and receptor for advanced-glycation-end-products, and the proliferation of mesangial cells. The injection of advanced-glycation-end-product-cholesterol-aggregated-BSA caused glomerular changes and albuminuria in non-diabetic mice. A transforming-growth-factor-beta receptor 1 kinase inhibitor or Mitogen-activated-Protein-Kinase/Extracellular-Signal-regulated-Kinase kinase (ERK) inhibitor (U-0126) suppressed the proliferation of mesangial cells induced by advanced-glycation-end-product-cholesterol-aggregated-BSA dose-dependently. U-0126 inhibited the phosphorylation of ERK1/2 in advanced-glycation-end-product-cholesterol-aggregated-BSA treated mesangial cells. These findings suggested that cholesterol promotes the formation of advanced-glycation-end-products-protein and that advanced-glycation-end-product-cholesterol-aggregated protein stimulates mesangial cells to proliferate via transforming-growth-factor-beta receptors and the ERK-MAPK pathway in diabetic glomeruli.
高血糖和高血脂被认为是糖尿病肾病发展的关键。本研究旨在阐明胆固醇对晚期糖基化终产物的影响及其在晚期糖基化终产物-胆固醇聚集牛血清白蛋白（BSA）诱导的系膜细胞增殖中的作用机制。用晚期糖基化终产物-胆固醇聚集的 BSA 处理系膜细胞，分离 RNA 和蛋白质。胆固醇使荧光强度增加 1.5 倍，体外晚期糖基化终产物增加 2 倍。吡哆胺、氨基胍和 N-乙酰-L-半胱氨酸抑制晚期糖基化终产物-胆固醇聚集的 BSA 的产生。用基质辅助激光解吸/电离飞行时间质谱分析晚期糖基化终产物-胆固醇-BSA，发现峰向更高质量移动。晚期糖基化终产物-胆固醇聚集的 BSA 诱导转化生长因子-β1、胶原 1 型、胶原 4 型和晚期糖基化终产物受体的 mRNA 过度表达，以及系膜细胞的增殖。晚期糖基化终产物-胆固醇聚集的 BSA 注射导致非糖尿病小鼠肾小球变化和白蛋白尿。转化生长因子-β受体 1 激酶抑制剂或丝裂原活化蛋白激酶/细胞外信号调节激酶激酶（ERK）抑制剂（U-0126）剂量依赖性地抑制晚期糖基化终产物-胆固醇聚集的 BSA 诱导的系膜细胞增殖。U-0126 抑制晚期糖基化终产物-胆固醇聚集的 BSA 处理的系膜细胞中 ERK1/2 的磷酸化。这些发现表明胆固醇促进晚期糖基化终产物-蛋白质的形成，晚期糖基化终产物-胆固醇聚集的蛋白质通过转化生长因子-β受体和 ERK-MAPK 途径刺激糖尿病肾小球中的系膜细胞增殖。
