摘要
背景:肝脏来源的胞外膜粒可介导细胞间通讯、调控肝细胞的增殖与分化,在肝病诊断、肝癌防治、肝脏再生和细胞移植等技术的研究应用中均有重要价值。但由于对膜粒的发生和类型归属缺乏认识,制约了该领域的进展。隧道纳米管是介导细胞间通讯的另一新发现的结构,是否存在于肝细胞间尚无报道。目的:通过对比人正常胎肝细胞和肝癌细胞表面超微结构的特点,寻找两种细胞的差异,揭示胞外膜粒的生物发生过程,判断其类型归属,明确隧道纳米管是否存在。方法:用扫描电镜观察处于增殖周期中的贴壁培养胎肝 L02 和肝癌 BEL-7402 细胞样品,分析其细胞表面超微结构的共性和差异。结果与结论:首次显示人胎肝 L02 和肝癌 BEL-7402 细胞表面均具有大量微绒毛样突起,其特征与静止期细胞的典型微绒毛有显著差异。L02 细胞上微绒毛样突起的平均长度和密度均超过 BEL-7402 细胞,可作为区分两种细胞的指标。两种细胞上的微绒毛样突起均既可产生纳米膜粒,又可转化为隧道纳米管。纳米膜粒的产生方式有出芽和串珠样缢缩两种类型。总之,高分辨率扫描电镜图像可作为鉴定肝脏来源细胞表面超微结构特征和胞外膜粒来源的金标准。
BACKGROUND：Liver-derived extracellular membrane particles can mediate cell-cell communication and regulate proliferation/differentiation of hepatocytes, and therefore have important application values in diagnosis of liver diseases, in prevention and treatment of liver cancers, and in development of techniques for liver regeneration and cell transplantation.However, progress in the field is hampered by limited knowledge about the origination and typological classification of liver-derived membrane particles.Tunneling nanotube （TNT） is anther newly discovered structure that also mediates cell-cell communication.However, the question whether TNT exists in hepatocytes remains unanswered.OBJECTIVE：By comparing ultrastructural characteristics of the cell surfaces of human normal fetal liver and hepatocellular carcinoma cells, the study is aimed to find the differences between normal and cancerous cells, to uncover the biogenesis of membrane particles so as to accurately classify the particles, and to assure the existence of TNT in liver cells.METHODS：A scanning electron microscope （SEM） was used to probe the samples prepared from cycling adhered fetal hepatocytes L02 and hepatocellular carcinoma BEL-7402 cells to analyze the commonness and difference of cell surface ultrastructure.RESULTS AND CONCLUSION：Extensive microvillus-like protrusions were revealed for the first time on the cell surfaces of both L02 and BEL-7402 cells.The protrusions were characteristically different with the typical microvilli on resting cells.Compared with the BEL-7402 cells, however, the average length and density of the microvillus-like protrusions were longer and higher on the L02 cells, which could be used as a guide to differentiate the two cells.Microvillus-like protrusions from the two cells could either generate nanoparticles or transform into TNT.Two types of nanoparticle biogenesis, budding and pearl-forming constriction, were observed.Taken together, high-resolution SEM images can be served as gold standard to characterize the surface ultrastructures on liver-derived cells, and to pinpoint the sources of extracellular membrane particles.
出处
《中国组织工程研究与临床康复》
CAS
CSCD
北大核心
2010年第36期6785-6789,共5页
Journal of Clinical Rehabilitative Tissue Engineering Research
基金
国家自然科学基金资助项目(30570413)
北京大学985细胞生物学重点学科建设项目~~
