Basson M D, Li G D, Hong F, Han O, Sumpio B E
Department of Surgery, Yale University School of Medicine, New Haven, Connecticut, USA.
J Cell Physiol. 1996 Aug;168(2):476-88. doi: 10.1002/(SICI)1097-4652(199608)168:2<476::AID-JCP26>3.0.CO;2-#.
Little is known about the effects of repetitive deformation during peristaltic distension and contraction or repetitive villus shortening on the proliferation and differentiation of the intestinal epithelium. We sought to characterize the effects of repetitive deformation of a physiologically relevant magnitude and frequency on the proliferation and differentiation of human intestinal epithelial Caco-2 cells, a common cell culture model for intestinal epithelial biology. Human intestinal epithelial Caco-2 cells were cultured on collagen-coated membranes deformed by -20 kPa vacuum at 10 cycles/minute, producing an average 10% strain on the adherent cells. Proliferation was assessed by cell counting and 3H-thymidine incorporation. Alkaline phosphatase and dipeptidyl dipeptidase specific activity were measured in cell lysates. Since cells at the membrane periphery experience higher strain than cells in the center, the topography of brush border enzyme histochemical and immunohistochemical staining was analyzed for strain-dependence. Cyclic strain stimulated proliferation compared to static cells. Proliferation was highest in the membrane periphery where strain was maximal. Strain also modulated differentiation independently of its mitogenic effects, selectively stimulating dipeptidyl dipeptidase while inhibiting alkaline phosphatase. Strain-associated enzyme changes were also maximal in areas of greatest strain. The PKC inhibitors staurosporine and calphostin C ablated strain mitogenic effects while intracellular PKC activity was increased by strain. The strain-associated brush border enzyme changes were attenuated but not blocked by PKC inhibition. Thus, strain of a physiologically relevant frequency and magnitude promotes proliferation and modulates the differentiation of a well-differentiated human intestinal epithelial cell line in an amplitude-dependent fashion. PKC may be involved in coupling strain to increased proliferation.
关于蠕动性扩张和收缩过程中的反复变形或绒毛反复缩短对肠上皮细胞增殖和分化的影响，人们了解甚少。我们试图描述具有生理相关幅度和频率的反复变形对人肠上皮Caco-2细胞增殖和分化的影响，Caco-2细胞是肠上皮生物学中常用的细胞培养模型。将人肠上皮Caco-2细胞培养在经胶原包被的膜上，该膜通过-20 kPa真空以每分钟10次循环进行变形，使贴壁细胞产生平均10%的应变。通过细胞计数和3H-胸腺嘧啶核苷掺入评估增殖情况。在细胞裂解物中测量碱性磷酸酶和二肽基肽酶的比活性。由于膜周边的细胞比中心的细胞经历更高的应变，因此分析刷状缘酶组织化学和免疫组织化学染色的拓扑结构以确定其应变依赖性。与静态细胞相比，周期性应变刺激了增殖。在应变最大的膜周边增殖最高。应变还独立于其促有丝分裂作用调节分化，选择性地刺激二肽基肽酶同时抑制碱性磷酸酶。与应变相关的酶变化在应变最大的区域也最大。PKC抑制剂星形孢菌素和钙泊三醇消除了应变的促有丝分裂作用，而细胞内PKC活性因应变而增加。与应变相关的刷状缘酶变化通过PKC抑制而减弱但未被阻断。因此，具有生理相关频率和幅度的应变以幅度依赖性方式促进增殖并调节高度分化的人肠上皮细胞系的分化。PKC可能参与将应变与增殖增加相偶联。
