Senoo Haruki, Imai Katsuyuki, Matano Yoshikazu, Sato Mitsuru
Department of Anatomy, Akita University School of Medicine, Akita, Japan.
J Gastroenterol Hepatol. 1998 Sep;13(S1):S19-S32. doi: 10.1111/jgh.1998.13.s1.19.
Hepatic stellate cells (vitamin A-storing cells, lipocytes, interstitial cells, fat-storing cells, Ito cells) exist in the perisinusoidal space of the hepatic lobule and store 80% of the body's retinoids as retinyl palmitate in lipid droplets in the cytoplasm. Under 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. However, in pathological conditions such as liver fibrosis, these cells lose retinoids and synthesize a large amount of extracellular matrix (ECM) components including collagen, proteoglycan and adhesive glycoproteins. The morphology of these cells also changes from 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 hepatic stellate cells. Molecular mechanisms in the reversible regulation of stellate cells by ECM imply cell surface integrin binding to ECM components followed by signal transduction processes and then cytoskeleton assembly.
肝星状细胞（维生素A储存细胞、脂肪细胞、间质细胞、贮脂细胞、伊托细胞）存在于肝小叶的窦周间隙，将机体80%的类视黄醇以棕榈酸视黄酯的形式储存于细胞质的脂滴中。在生理条件下，这些细胞在类视黄醇稳态调节中起关键作用；它们在细胞表面表达视黄醇结合蛋白（RBP，一种视黄醇特异性结合蛋白）的特异性受体，并通过受体介导的内吞作用摄取视黄醇与RBP的复合物。然而，在肝纤维化等病理条件下，这些细胞失去类视黄醇并合成大量细胞外基质（ECM）成分，包括胶原蛋白、蛋白聚糖和黏附糖蛋白。这些细胞的形态也从星形的星状细胞转变为成纤维细胞或肌成纤维细胞的形态。已发现ECM成分的三维结构可可逆地调节肝星状细胞的形态、增殖和功能。ECM对星状细胞可逆调节的分子机制意味着细胞表面整合素与ECM成分结合，随后进行信号转导过程，然后是细胞骨架组装。
