Structure and function of hepatic stellate cells
Structure and function of hepatic stellate cells
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DOI：
10.1007/s00795-003-0230-3
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发表时间：
2004-03-01
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影响因子：
--
通讯作者：
Senoo, Haruki
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文献类型：
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作者：
Senoo, Haruki
肝星状细胞（维生素A储存细胞、脂肪细胞、间质细胞、脂肪储存细胞、Ito细胞）存在于肝小叶的实质细胞和窦状内皮细胞之间的空间中，并且将全身80%的类维生素A以棕榈酸视黄酯的形式储存在细胞质中的脂滴中。在生理条件下，这些细胞在调节类维生素A稳态中发挥关键作用;它们在细胞表面表达视黄醇结合蛋白（RBP）的特异性受体，RBP是一种对视黄醇特异性的结合蛋白，并通过受体介导的内吞作用吸收视黄醇和RBP的复合物。在北极动物如北极熊和北极狐的肝星状细胞中，类维生素A的含量是人类或大鼠的20100倍。在肝纤维化等病理条件下，肝星状细胞失去类维生素A，并合成大量细胞外基质（ECM）组分，包括胶原蛋白、蛋白聚糖和粘附糖蛋白。这些细胞的形态也从星形星状细胞变为成纤维细胞或肌成纤维细胞。发现ECM组分的三维结构可逆地调节肝星状细胞的形态、增殖和功能。ECM对星状细胞可逆调控的分子机制暗示细胞表面整合素与ECM成分结合，随后是信号转导过程，然后是细胞骨架组装。星状细胞也存在于肝外器官如胰腺、肺、肾和肠中。肝星状细胞和肝外星状细胞构成星状细胞系统。
Hepatic stellate cells (vitamin A-storing cells, lipocytes, interstitial cells, fat-storing cells, Ito cells) exist in the space between parenchymal cells and sinusoidal endothelial cells of the hepatic lobule and store 80% of retinoids in the whole body as retinyl palmitate in lipid droplets in the cytoplasm. In physiological conditions, these cells play pivotal roles in the regulation of retinoid homeostasis; they express specific receptors for retinol-binding protein (RBP), a binding protein specific for retinol, on their cell surface, and take up the complex of retinol and RBP by receptor-mediated endocytosis. Hepatic stellate cells in arctic animals such as polar bears and arctic foxes store 20100 times the levels of retinoids found in humans or rats. In pathological conditions such as liver fibrosis, hepatic stellate cells lose retinoids, and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan, and adhesive glycoproteins. Morphology of these cells also changes from the star-shaped stellate cells to that of fibroblasts or myofibroblasts. The three-dimensional structure of ECM components was found to regulate reversibly the morphology, proliferation, and functions of the hepatic stellate cells. Molecular mechanisms in the reversible regulation of the stellate cells by ECM imply cell-surface integrin binding to ECM components, followed by signal transduction processes and then cytoskeleton assembly. Stellate cells also exist in extrahepatic organs such as pancreas, lung, kidney, and intestine. Hepatic and extrahepatic stellate cells form the stellate cell system.