ABSTRACT
Objective To explore the influence of integrin redistribution on hepatoma cell alignment and migration and the influence of cytoskeleton reassembly on integrin redistribution by the method of mechanical loading unloading and fibronection(FN) coating. Method By using immuneofluescence staining, cofocal laser scanning microscopy and quantitative morphological analysis, integrin distribution change and crtoskeleton assembly adjustment were observed and the deformation of cell movement was tested and analyzed quantitatively. Results (1) cells with different forms have different integrin expressions and distribution features. The β1 integrin expression for spreading cells was higher than that for round (nonspreading) cells. For spreading cells, the strongest staining was found towards the attachment surface. While for round (nonspreading) cells, the integrin staining on the free surface towards medium was stronger than that towards the attachment surface. (2) After 5 hours of mechanical stretch, the β1 integrin expression for both spreading and round cells increased, and distribution peaks towards the attachment surface broadened. At 1 hour after unloading, the β1 integrin expression decreased and the distribution of integrin staining showed the tendency of dispersion, especially for round cells. (3) After coating the substrates with FN, the β1 integrin expression increased. The integrin staining for either spreading or round cells was more towards the attachment surface to reduce the migration of hepatoma cells. 4) After 5 hours of mechanical stretch, 60% of cells showed their orientation of major axes distributed between 70°～110° towards the stretching direction, and the cytoskeleton aligned vertically to the stretching direction. Cytoskeletons were found significantly depolymerized at 1 hour of unloading. Conclusions The change of integrin distribution is affected by cytoskeleton aligned and the number of ligand. The distribution feature of the whole integrin expression on the surface of individual round cells is related to their stronger invasion and metastasis capability.
ABSTRACT
<p><b>OBJECTIVE</b>To investigate the effects of burn serum on the viscoelasticity and the structure of rat intestinal epithelial cells.</p><p><b>METHODS</b>The rat intestinal epithelial cell strain (IEC-6) was cultured and stimulated by burn serum. The changes of IECs before and after the stimulation were dynamically observed by cytoskeleton immunohistochemistry, ELISA and the measurement of cytomembranous viscoelasticity.</p><p><b>RESULTS</b>During the early stage of burn serum stimulation, the skeleton protein expression in IEC decreased obviously with weakened positive signals of microfilaments and microtubules and with decreased cellular elasticity.</p><p><b>CONCLUSION</b>The cytoskeleton injury could cause the increase of cellular fragility and the decrease of the viscoelasticity, which ultimately lead to the change of cellular biodynamics. These changes might directly participate the development of postburn intestinal epithelial injury.</p>
Subject(s)
Animals , Male , Rats , Actins , Burns , Blood , Cell Line , Culture Media , Pharmacology , Cytoskeletal Proteins , Metabolism , Elasticity , Epithelial Cells , Cell Biology , Metabolism , Immunohistochemistry , Intestinal Mucosa , Cell Biology , Metabolism , Rats, Wistar , Tubulin , ViscosityABSTRACT
<p><b>OBJECTIVE</b>To study the effects of integrin beta1 on the chemotaxis of hepatocellular carcinoma (HCC) cells to laminin (LN).</p><p><b>METHODS</b>A micropipette technique was adopted to investigate the effect of integrin beta1 blockade on pseudopod protrusion of HCC cells in response to LN stimulation. Chemotactic pseudopod protrusion of a HCC cell was evaluated using a dual-pipette set-up, in which two pipettes filled with LN solution were positional in close contact with the same cell, and pseudopod protrusion into each pipette was viewed dynamically and recorded with a tape recorder. The lengths of pseudopods were measured, then plotted against time to obtain a pseudopod growth curve. The integrin beta1 subunit on the surfaces of HCC cells was analyzed by flow cytometry.</p><p><b>RESULTS</b>In dual pipette chemotaxis experiment, when the two pipettes were filled with LN (50microg/ml, 200microg/ml), pseudopods extended from the HCC cells into each of the pipettes nearly symmetrically. Upon addition of anti-CD29 (20microg/ml) to one of the pipettes, the pseudopod protrusion was blocked almost completely, while the pseudopod protrusion into the opposite pipette became more evidently, with larger maximum length. The expression rate of integrin beta1 on the cells was up to 95.78%.</p><p><b>CONCLUSION</b>Integrin beta1 subunit is the important receptor for mediating HCC cells chemotaxis to laminin.</p>