Avossa D, Pfeiffer S E
Department of Microbiology, University of Connecticut Health Center, Farmington 06030.
J Neurosci Res. 1993 Jan;34(1):113-28. doi: 10.1002/jnr.490340112.
The physiological importance of protein kinase C during oligodendrocyte progenitor maturation was investigated by analyzing the effects of the protein kinase C activator phorbol 12-myristate 13-acetate (TPA) on the morphology, proliferation, and differentiation of oligodendrocytes at sequential stages of development. Monoclonal antibodies A2B5 and O4 were used to identify the A2B5+O4- and the A2B5+O4+ galactocerebroside- progenitor stages. Anti-galactocerebroside and anti-myelin basic protein were used to identify mature, post-mitotic oligodendrocytes. Proliferation was measured by bromodeoxyuridine incorporation. Within 24 hr after addition, TPA induced a down-regulation of the O4 antigen in OL progenitors, and an increase of expression of the intermediate filament protein vimentin, leading to a phenotypic reversion from the vimentin-A2B5+O4+ phenotype to the less mature vimentin+A2B5+O4- stage. Concomitantly, TPA induced an increase in the number of bromodeoxyuridine-labeled oligodendrocyte progenitors and extensive process elongation. The response of O4+ progenitors was transient. Even with continued exposure to TPA, by 4 days after TPA addition the reverted cells ceased proliferation, reacquired O4 immunoreactivity, became vimentin-negative, and began to express galactocerebroside and myelin basic protein, and to display the complex, highly branched morphology characteristic of terminally differentiated oligodendrocytes. These results indicate that modulation of protein kinase C activity by TPA induces a transient reversion of O4+ progenitors to less mature O4- cells, causing a transient inhibition of terminal differentiation. The relationship of these data to similar responses of the OL lineage to specific growth factors and implications for remyelination after pathologic injury are discussed.
通过分析蛋白激酶C激活剂佛波醇12 -肉豆蔻酸酯13 -乙酸酯（TPA）对少突胶质细胞发育连续阶段的形态、增殖和分化的影响，研究了蛋白激酶C在少突胶质前体细胞成熟过程中的生理重要性。使用单克隆抗体A2B5和O4来识别A2B5 + O4 -和A2B5 + O4 +半乳糖脑苷脂前体细胞阶段。使用抗半乳糖脑苷脂和抗髓鞘碱性蛋白来识别成熟的、有丝分裂后的少突胶质细胞。通过溴脱氧尿苷掺入法测量增殖。添加TPA后24小时内，TPA诱导少突胶质前体细胞中O4抗原下调，中间丝蛋白波形蛋白表达增加，导致表型从波形蛋白 - A2B5 + O4 +表型逆转为不太成熟的波形蛋白 + A2B5 + O4 -阶段。同时，TPA诱导溴脱氧尿苷标记的少突胶质前体细胞数量增加和广泛的突起伸长。O4 +前体细胞的反应是短暂的。即使持续暴露于TPA，在添加TPA后4天，逆转的细胞停止增殖，重新获得O4免疫反应性，变为波形蛋白阴性，并开始表达半乳糖脑苷脂和髓鞘碱性蛋白，并呈现终末分化少突胶质细胞特有的复杂、高度分支的形态。这些结果表明，TPA对蛋白激酶C活性的调节诱导O4 +前体细胞短暂逆转为不太成熟的O4 -细胞，导致终末分化的短暂抑制。讨论了这些数据与少突胶质细胞系对特定生长因子的类似反应的关系以及对病理性损伤后髓鞘再生的意义。
