Lamp2a参与Plin5在肝脏脂质分解中的作用

摘要

目的:探讨肝脏中lamp2a对plin5表达及其功能的影响.方法:利用Western blot及免疫组化检测正常人和脂肪肝患者肝脏中lamp2a与plin5表达相关性.利用HepG2细胞构建lamp2a敲减的细胞系HepG2-L2A,通过给予油酸刺激、溶酶体抑制剂处理等进一步在细胞水平证实其相关性.结果:Western-Blot及免疫组化检测显示脂肪肝患者肝组织中lamp2a的表达明显下降,而plin5表达显著升高.Western-Blot试验提示正常培养的HepG2-L2A细胞中plin5表达较HepG2细胞中升高,Bodipy染色提示HepG2-L2A细胞中脂滴数量也明显增加(124± 15.3 vs 273± 19.1).在分解试验中,HepG2细胞中plin5明显降低,脂滴数量也明显减少(282± 24.1 vs 192± 17.5);而HepG2-L2A细胞中plin5仍然处于高水平,脂滴数量仍然较多(325± 24.0 vs 286土28.7).当给予溶酶体抑制剂处理时,HepG2细胞中plin5降解明显抑制,而HepG2-L2A中plin5水平未见明显改变.结论:肝脏中lamp2a的异常表达影响plin5的表达,进而影响了脂质的分解.%Objective:To explore the effect that lamp2a regulates expression and function ofplin5 in liver.Methods:Western Blot and immunohistochemical staining were applied to detect the expression of lamp2a and plin5 as well as their relationship in liver.To further investigate their relation in cellular level,we built a cell lines named HepG2-L2A that lamp2a was knocked out.In the condition of containing oil acid or lysosome inhibitor,the expression level of lamp2a and plin5 was detected in HepG2 and HepG2-L2A cells.Results:Western Blot and immunohistochemical staining suggested,in the liver of patients with nonalcoholic fatty liver disease,the expression of lamp2a was significantly reduced but plin5 markedly increased as compared to normal humans.Western Blot showed that expression of plin5 in HepG2-L2A was moderately increased in regular cultivation,Bodipy staining showed number of lipid droplets in HepG2-L2A also increased (124± 15.3 vs 273± 19.1).However,the level ofplin5 was sharply reduced in HepG2 but no obvious alteration was observed in HepG2-L2A when cells were cultivated with medium not contained serum after oil acid was taken.Likewise,the number of lipid droplets was obviously lessened in HepG2(282± 24.1 vs 192±17.5)but no significant reduce in HepG2-L2A(325± 24.0 vs 286±28.7)when cultivated as above.Besides,there was distinct increase in plin5 expression in HepG2 when lysosome inhibitor was given,but no change of plin5 expression in HepG2-L2A.Conclusions:In liver,the abnomal expression of lamp2a influenced the expression of plin5 as well as lipidolysis.