Herrema Hilde, Czajkowska Dominika, Théard Delphine, van der Wouden Johanna M, Kalicharan Dharamdajal, Zolghadr Behnam, Hoekstra Dick, van Ijzendoorn Sven C D
Membrane Cell Biology and Electron Microscopy, Department of Cell Biology, University Medical Center Groningen, University of Groningen, 9713 AV Groningen, The Netherlands.
Mol Biol Cell. 2006 Jul;17(7):3291-303. doi: 10.1091/mbc.e06-01-0067. Epub 2006 May 10.
The molecular mechanisms that regulate multicellular architecture and the development of extended apical bile canalicular lumens in hepatocytes are poorly understood. Here, we show that hepatic HepG2 cells cultured on glass coverslips first develop intercellular apical lumens typically formed by a pair of cells. Prolonged cell culture results in extensive organizational changes, including cell clustering, multilayering, and apical lumen morphogenesis. The latter includes the development of large acinar structures and subsequent elongated canalicular lumens that span multiple cells. These morphological changes closely resemble the early organizational pattern during development, regeneration, and neoplasia of the liver and are rapidly induced when cells are cultured on predeposited extracellular matrix (ECM). Inhibition of Rho kinase or its target myosin-II ATPase in cells cultured on glass coverslips mimics the morphogenic response to ECM. Consistently, stimulation of Rho kinase and subsequent myosin-II ATPase activity by lipoxygenase-controlled eicosatetranoic acid metabolism inhibits ECM-mediated cell multilayering and apical lumen morphogenesis but not initial apical lumen formation. Furthermore, apical lumen remodeling but not cell multilayering requires basal p42/44 MAPK activity. Together, the data suggest a role for hepatocyte-derived ECM in the spatial organization of hepatocytes and apical lumen morphogenesis and identify Rho kinase, myosin-II, and MAPK as potentially important players in different aspects of bile canalicular lumen morphogenesis.
调节多细胞结构以及肝细胞中扩展的顶端胆小管腔发育的分子机制尚不清楚。在此，我们表明，在玻璃盖玻片上培养的肝HepG2细胞首先形成通常由一对细胞形成的细胞间顶端腔。长时间的细胞培养导致广泛的组织变化，包括细胞聚集、多层化和顶端腔形态发生。后者包括大腺泡结构的发育以及随后跨越多个细胞的细长胆小管腔的形成。这些形态变化与肝脏发育、再生和肿瘤形成过程中的早期组织模式非常相似，并且当细胞在预先沉积的细胞外基质（ECM）上培养时会迅速诱导。在玻璃盖玻片上培养的细胞中抑制Rho激酶或其靶标肌球蛋白-II ATP酶可模拟对ECM的形态发生反应。一致地，脂氧合酶控制的二十碳四烯酸代谢对Rho激酶和随后的肌球蛋白-II ATP酶活性的刺激会抑制ECM介导的细胞多层化和顶端腔形态发生，但不会抑制初始顶端腔的形成。此外，顶端腔重塑而非细胞多层化需要基础p42/44 MAPK活性。总之，这些数据表明肝细胞衍生的ECM在肝细胞的空间组织和顶端腔形态发生中起作用，并确定Rho激酶、肌球蛋白-II和MAPK是胆小管腔形态发生不同方面的潜在重要参与者。
