Espinosa de los Monteros A, Kumar S, Scully S, Cole R, de Vellis J
Department of Anatomy and Cell Biology, University of California, Los Angeles.
J Neurosci Res. 1990 Apr;25(4):576-80. doi: 10.1002/jnr.490250416.
We have previously shown by immunocytochemistry in rat primary glial cultures that transferrin (Tf) is an early developmental marker for oligodendrocytes. The present work addresses the issue of Tf gene expression and synthesis by neural cells in vitro. For this purpose, we used rat embryonic neuronal cultures and newborn glial cultures of astrocytes and oligodendrocytes. Cultured fibroblasts and C6 glioma cells were used as negative controls. We found that Tf mRNA is present in oligodendrocytes, astrocytes, and neurons. However, oligodendrocytes and astrocytes, but not neurons, were shown to synthesize and secrete Tf. Neither fibroblasts nor C6 glioma cells expressed detectable amounts of Tf mRNA. Tf mRNA levels in astrocyte cultures appeared to be under hormonal control since hydrocortisone markedly reduced message levels. These results show that both astrocytes and oligodendrocytes can synthesize and secrete Tf under cell culture conditions. However, epigenetic factors, such as hydrocortisone, may repress the expression of Tf in astrocytes in vivo.
我们之前通过免疫细胞化学方法在大鼠原代神经胶质细胞培养物中发现，转铁蛋白（Tf）是少突胶质细胞早期发育的标志物。目前的工作探讨了神经细胞在体外对Tf基因的表达和合成问题。为此，我们使用了大鼠胚胎神经元培养物以及新生星形胶质细胞和少突胶质细胞的神经胶质细胞培养物。培养的成纤维细胞和C6胶质瘤细胞用作阴性对照。我们发现，Tf mRNA存在于少突胶质细胞、星形胶质细胞和神经元中。然而，研究表明，少突胶质细胞和星形胶质细胞能够合成并分泌Tf，而神经元则不能。成纤维细胞和C6胶质瘤细胞均未表达可检测量的Tf mRNA。星形胶质细胞培养物中的Tf mRNA水平似乎受激素控制，因为氢化可的松显著降低了其mRNA水平。这些结果表明，在细胞培养条件下，星形胶质细胞和少突胶质细胞均能合成并分泌Tf。然而，诸如氢化可的松等表观遗传因素可能在体内抑制星形胶质细胞中Tf的表达。
