Fok-Seang J, Miller R H
Department of Neurosciences, Case Western Reserve University, Cleveland, Ohio 44106.
J Neurosci Res. 1994 Feb 1;37(2):219-35. doi: 10.1002/jnr.490370208.
In many regions of the rat central nervous system, oligodendrocytes develop from migratory A2B5+ precursor cells. In the rat spinal cord, during early embryonic development the capacity for oligodendrogenesis appears to be restricted to ventral regions of the spinal cord, while cultures of postnatal rat spinal cord contain a distinct population of A2B5+ astrocyte precursors. To determine if, as in other regions of the CNS, spinal cord A2B5+ cells give rise directly to oligodendrocytes and astrocytes, the initial distribution, and subsequent dispersion, proliferation, and differentiation of spinal cord A2B5+ cells have been examined in both explant and dissociated cell cultures. Spinal cord oligodendrocytes develop from A2B5+ cells. At E14, A2B5+ cells are restricted to ventral regions of the spinal cord and as development proceeds they become more uniformly distributed throughout the spinal cord. In explant cultures, greater than 95% of the explants that contain oligodendrocytes also contain A2B5+ cells and a proportion of mature oligodendrocytes retain detectable A2B5 immunoreactivity briefly on their surface. The maturation of spinal cord oligodendrocyte precursors occurs in a number of distinct stages characterized by the expression of O4 immunoreactivity, which first appears at E16, and GC immunoreactivity, which first appears at E18. As spinal cord oligodendrocyte precursors acquire O4 immunoreactivity they appear to lose the ability to proliferate in response to PDGF but retain the ability to proliferate in response to bFGF, suggesting that the control of proliferation of oligodendrocyte precursors is, in part, dependent on their maturational state. In the presence of high serum, spinal cord A2B5+ cells fail to develop in isolated E14 dorsal spinal cord cultures, while in ventral cultures they subsequently differentiate into A2B5+ astrocytes suggesting that A2B5+ astrocyte precursors are also initially ventrally located. Unlike oligodendrocyte differentiation, however, the differentiation of spinal cord A2B5+ cells into astrocytes is delayed in early embryonic-derived cultures compared to those from older animals. These observations suggest that local influences may regulate the timing of spinal cord A2B5+ astrocyte development, but not spinal cord oligodendrocyte development.
在大鼠中枢神经系统的许多区域，少突胶质细胞由迁移性A2B5 +前体细胞发育而来。在大鼠脊髓中，胚胎早期发育期间，少突胶质细胞生成能力似乎局限于脊髓腹侧区域，而出生后大鼠脊髓培养物中含有一群独特的A2B5 +星形胶质细胞前体。为了确定脊髓A2B5 +细胞是否如中枢神经系统其他区域一样直接产生少突胶质细胞和星形胶质细胞，研究人员在植块培养和离体细胞培养中检测了脊髓A2B5 +细胞的初始分布以及随后的分散、增殖和分化情况。脊髓少突胶质细胞由A2B5 +细胞发育而来。在胚胎第14天（E14）时，A2B5 +细胞局限于脊髓腹侧区域，随着发育进行，它们在整个脊髓中分布得更加均匀。在植块培养中，含有少突胶质细胞的植块中超过95%也含有A2B5 +细胞，并且一部分成熟少突胶质细胞在其表面短暂保留可检测到的A2B5免疫反应性。脊髓少突胶质细胞前体的成熟发生在多个不同阶段，其特征是O4免疫反应性的表达（首次出现在E16）和GC免疫反应性的表达（首次出现在E18）。随着脊髓少突胶质细胞前体获得O4免疫反应性，它们似乎失去了对血小板源性生长因子（PDGF）增殖反应的能力，但保留了对碱性成纤维细胞生长因子（bFGF）增殖反应的能力，这表明少突胶质细胞前体增殖的控制部分取决于它们的成熟状态。在高血清存在的情况下，分离的E14脊髓背侧培养物中脊髓A2B5 +细胞无法发育，而在腹侧培养物中它们随后分化为A2B5 +星形胶质细胞，这表明A2B5 +星形胶质细胞前体最初也位于腹侧。然而，与少突胶质细胞分化不同，与来自成年动物的培养物相比，胚胎早期来源的培养物中脊髓A2B5 +细胞向星形胶质细胞的分化延迟。这些观察结果表明，局部影响可能调节脊髓A2B5 +星形胶质细胞发育的时间，但不调节脊髓少突胶质细胞的发育。
