Boraldi Federica, Croce Maria Antonietta, Quaglino Daniela, Sammarco Rita, Carnevali Elena, Tiozzo Roberta, Pasquali-Ronchetti Ivonne
Department of Biomedical Sciences, University of Modena and Reggio Emilia, Via Campi, 287, Modena 41100, Italy.
Tissue Cell. 2003 Feb;35(1):37-45. doi: 10.1016/s0040-8166(02)00101-5.
Normal human skin fibroblasts were grown in a three-dimensional collagen gel or in monolayer in the presence or absence of high molecular weight hyaluronan (HA) to assess the influence of extracellular HA on cell-matrix interactions. HA incorporated into the collagen gel or added to the culture medium did not modify lattice retraction with time. The effect was independent from HA molecular weight (from 7.5 x 10(5) to 2.7 x 10(6) Da) and concentration (from 0.1 up to 1 mg/ml). HA did not affect shape and distribution of fibroblasts within the gel, whereas it induced the actin filaments to organise into thicker cables running underneath the plasma membrane. The same phenomenon was observed in fibroblasts grown in monolayer. By contrast, vimentin cytoskeleton and cell-substrate focal adhesions were not modified by exogenous HA. The number of fibroblasts attached to HA-coated dishes was always significantly lower compared to plastic and to collagen type I-coated plates. By contrast, adhesion was not affected by soluble HA added to the medium nor by anti-CD44 and anti-RHAMM-IHABP polyclonals. After 24-h seeding on collagen type I or on plastic, cells were large and spread. Conversely, cells adherent to HA-coated surfaces were long, thin and aligned into rows; alcian blue showed that cells were attached to the plastic in between HA bundles. Therefore, normal human skin fibroblasts exhibit very scarce, if any, adhesion to matrix HA, either soluble or immobilised. Moreover, even at high concentration, HA molecules do not exert any visco-mechanical effect on lattice retraction and do not interfere with fibroblast-collagen interactions nor with focal adhesion contacts of fibroblasts with the substrate. This is probably relevant in organogenesis and wound repair. By contrast, HA greatly modifies the organisation of the actin cytoskeleton, suggesting that CD44-mediated signal transduction by HA may affect cell locomotion and orientation, as indicated by the fusiform shape of fibroblasts grown in the presence of immobilised HA. A role of HA in cell orientation could be relevant for the deposition of collagen fibrils in regeneration and tissue remodelling.
将正常人皮肤成纤维细胞培养于三维胶原凝胶中，或在有无高分子量透明质酸（HA）存在的情况下进行单层培养，以评估细胞外HA对细胞-基质相互作用的影响。掺入胶原凝胶或添加到培养基中的HA不会随时间改变凝胶收缩。该效应与HA分子量（7.5×10⁵至2.7×10⁶Da）和浓度（0.1至1mg/ml）无关。HA不影响凝胶中成纤维细胞的形态和分布，而它会诱导肌动蛋白丝组织成更粗的束，在质膜下延伸。在单层培养的成纤维细胞中也观察到了同样的现象。相比之下，波形蛋白细胞骨架和细胞-底物黏着斑不受外源性HA的影响。与塑料培养皿和I型胶原包被的培养板相比，附着在HA包被培养皿上的成纤维细胞数量总是显著更低。相比之下，添加到培养基中的可溶性HA以及抗CD44和抗RHAMM-IHABP多克隆抗体均不影响细胞黏附。在I型胶原或塑料上接种24小时后，细胞大且铺展。相反，附着在HA包被表面的细胞长而细，并排列成行；阿尔辛蓝显示细胞附着在HA束之间的塑料上。因此，正常人皮肤成纤维细胞对基质HA（无论是可溶性还是固定化的）的黏附极少，甚至可以说几乎没有。此外，即使在高浓度下，HA分子对凝胶收缩也不产生任何黏弹性力学效应，并且不干扰成纤维细胞-胶原相互作用，也不干扰成纤维细胞与底物的黏着斑接触。这可能与器官发生和伤口修复有关。相比之下，HA极大地改变了肌动蛋白细胞骨架的组织，表明HA通过CD44介导的信号转导可能影响细胞运动和方向，固定化HA存在时生长的成纤维细胞呈梭形就表明了这一点。HA在细胞定向中的作用可能与再生和组织重塑过程中胶原纤维的沉积有关。
