Sanders E J, Cheung E
Department of Physiology, University of Alberta, Edmonton, Canada.
In Vitro Cell Dev Biol. 1988 Jun;24(6):581-7. doi: 10.1007/BF02629094.
Very early embryonic mesoderm cells were taken from the primitive streak-stage chick embryo and cultured in a matrix of type I collagen in the presence of serum. Previous work has shown that under these conditions cells do not leave the explant and move in the collagen in the absence of supplemented avian transferrin. Cells explanted onto tissue culture plastic in the presence of serum do not require this transferrin supplement. These observations were investigated further by culturing cells in collagen in the presence of the lipophilic iron chelator, ferric pyridoxal isonicotinoyl hydrazone (FePIH), which can replace transferrin as an iron-delivery agent. Under conditions in which FePIH could effectively stimulate chick embryo myoblast growth, no such long-term stimulation was obtained with the early mesoderm cells in collagen. This suggested that for mesoderm cells, FePIH could not replace transferrin. Antibody to the transferrin receptor and to transferrin itself inhibited growth of myoblasts in collagen and on plastic, and of mesoderm cells in collagen. Mesoderm cells on plastic, however, were refractory to the presence of the antibody directed to the receptor and seemed to show a low dependency on transferrin-delivered iron under these conditions, inasmuch as antiserum to transferrin itself only caused a partial inhibition of outgrowth. The results suggest that mesoderm cells in collagen require transferrin for both iron uptake and for another unspecified function. It is consistent with the results to propose that transferrin binding might modulate the cells' attachment to collagen, thus influencing outgrowth. The distribution of the actin cytoskeleton in mesoderm cells actively migrating in collagen, such as in the presence of transferrin, suggests a stronger attachment to the collagen than nonmigrating cells.
极早期胚胎中胚层细胞取自原条期鸡胚，并在血清存在的情况下于I型胶原蛋白基质中培养。先前的研究表明，在这些条件下，若不添加禽转铁蛋白，细胞不会离开外植体并在胶原蛋白中移动。在血清存在的情况下接种到组织培养塑料上的细胞则不需要这种转铁蛋白补充剂。通过在亲脂性铁螯合剂吡啶醛异烟酰腙铁（FePIH）存在的情况下于胶原蛋白中培养细胞，对这些观察结果进行了进一步研究，FePIH可替代转铁蛋白作为铁传递剂。在FePIH能够有效刺激鸡胚成肌细胞生长的条件下，胶原蛋白中的早期中胚层细胞未获得这种长期刺激。这表明对于中胚层细胞，FePIH无法替代转铁蛋白。转铁蛋白受体抗体和转铁蛋白本身抗体抑制了胶原蛋白中和塑料上的成肌细胞以及胶原蛋白中的中胚层细胞的生长。然而，塑料上的中胚层细胞对针对受体的抗体不敏感，并且在这些条件下似乎对转铁蛋白传递铁的依赖性较低，因为转铁蛋白本身的抗血清仅导致生长的部分抑制。结果表明，胶原蛋白中的中胚层细胞摄取铁以及另一种未明确的功能都需要转铁蛋白。提出转铁蛋白结合可能调节细胞与胶原蛋白的附着，从而影响生长，这与结果是一致的。在胶原蛋白中活跃迁移的中胚层细胞（如在转铁蛋白存在的情况下）中肌动蛋白细胞骨架的分布表明，其与胶原蛋白的附着比未迁移细胞更强。
