Protein kinase B/Akt signalling is required for palmitate-induced β-cell lipotoxicity
Protein kinase B/Akt signalling is required for palmitate-induced β-cell lipotoxicity
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DOI：
10.1111/j.1463-1326.2005.00488.x
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发表时间：
2006-03-01
影响因子：
5.8
通讯作者：
Inaba, T
中科院分区：
文献类型：
--
作者：
Higa, M;Shimabukuro, M;Inaba, T
目的：方法：用棕榈酸（C16：0）或油酸（C18：1）培养大鼠胰岛素瘤INS-1细胞（含或不含显性失活突变体Akt（K179 M）），用0.2%伊红染色法测定细胞数。Akt活性通过抗3 '-磷酸肌醇依赖性蛋白激酶（Akt）/蛋白激酶B（PKB）或抗磷酸Akt（丝氨酸473）免疫印迹和核蛋白核因子-kB（NF-κ B）结合活性通过超位移分析。用棕榈酸酯处理24小时增加了0.1-0.2 mm处的INS-1细胞数，但减少了0.5-1 mm处的细胞数。棕榈酸剂量依赖性地增加Akt/PKB中第473位丝氨酸的磷酸化。Akt/PKB的K179 M形式在低剂量下消除棕榈酸酯诱导的细胞增殖，在高剂量下消除死亡。核蛋白NF-κ B B结合在0.2和0.5 mm棕榈酸盐浓度下增强，而在1.0 mm棕榈酸盐浓度下降低。结论：Akt/PK B信号通路参与了棕榈酸盐诱导的胰岛β细胞死亡和存活。
Aim: This study was conducted to clarify cell death and survival signals in pancreatic beta-cell lipotoxicity.Methods: Rat insulinoma INS-1 cells, with or without expression of dominant-negative mutant of Akt (K179M), were cultured with palmitate (C16:0) or oleate (C18:1) and cell numbers were determined by 0.2% eosin dye exclusion assay. The Akt activity was determined by anti-3'-phospho-inositide-dependent protein kinase (Akt)/protein kinase B (PKB) or anti-phospho-Akt (Serine 473) immunoblotting, and nuclear protein nuclear factor-kB (NF-kappa B)-binding activity was by supershift analysis.Results: Twenty-four hours treatment with palmitate increased the INS-1 cell number at 0.1-0.2 mm but decreased the cell number at 0.5-1 mm. Oleate did not affect cell number at 0.1-1.0 mm. Palmitate dose-dependently increased phosphorylation of 473th serine in Akt/PKB. The K179M form of Akt/PKB abolished palmitate-induced cell proliferation at the low dose and death at the high dose. Nuclear protein NF-kappa B binding was enhanced at 0.2 and 0.5 mm of palmitate but decreased at 1.0 mm.Conclusion: Results suggest that Akt/PKB signalling is involved in palmitate-induced cell death and survival of pancreatic beta cell.