Induction of pericyte differentiation in human osteoblastic cell line

1.人成骨细胞系SV-HFO表达周细胞标志物，包括α-平滑肌肌动蛋白（SMA）、钙调蛋白和3G 5。在地塞米松诱导的成骨细胞分化过程中，它们的表达持续维持。此外，SMA的表达模式受到TGF-β 1和视黄酸的影响。TGF-β 1和维甲酸均减少SMA阳性细胞的数量。有趣的是，TGF-β 1在成骨细胞分化的非常早期（第4天）瞬时增加SMA阳性细胞的数量。由于TGF-β和视黄酸是SV-HFO矿化的抑制剂，它们对SMA表达的抑制作用表明成骨细胞分化和A周细胞分化受到相同的分子和生化机制的调节。SV-HFO W细胞与周细胞共享许多特征。此外，许多研究还表明周细胞是成骨细胞的前体细胞。因此，我们假设SV-HFO细胞可能与周细胞相同。SV-HFO细胞是否在体外或体内血管生成过程中起周细胞的作用值得进一步研究。2.我们研究了识别周细胞表面神经节苷脂的单克隆抗体3G 5在原位脑毛细血管上的表达。该抗体主要与毛细血管分支点或弯曲处的周细胞呈免疫反应性。Calponin、SMA和3G 5双染显示毛细血管中层周细胞同时表达Calponin和3G 5，但不表达SMA。由于3G 5抗体不能用于石蜡切片，因此calponin应该是比SMA或3G 5更好的周细胞标记物，并且对于研究肿瘤血管生成的免疫组化研究是有用的。

1. The human osteoblastic cell line, SV-HFO, expressed the pericyte markers including a-smooth muscle actin (SMA), calponin and 3G5. The expression of them was constantly mainteined during osteoblastic differentiation induced by dexamethasone. In addition, the pattern of expression of SMA was influenced by TGF-betal and retinoic acid. Both TGF-betal and retinoic acid decreased the number of SMA positive cells. Interestingly, TGF-betal transiently incereased the number of SMA positive cells in the very early stage of osteoblastic differentiation (the 4 day). Since TGF-beta and retinoic acid are the inhibitors of the mineralization of SV-HFO, the inhibitory effect of them on SMA expression suggested that osteoblastic differentiation and A pericyte differentiation are regulated by the same molecular and biochemical mechanism. SV-HFO W cells share many characteristics with pericytes. Furthermore, many studies have also suggested pericytes are the precursors to osteoblasts. Hence, we postulate that SV-HFO cells are possibly identical to pericytes. Whether SV-HFO cells function as pericytes during angiogenesis in vitro or in vivo warrant further investigation.2 .We investigated the expression of monoclonal antibody 3G5, which recognizes a ganglioside present on the surface of pericytes, on brain capillaries in situ. The antibody mainly showed immunoreactivity with pericytes located at the branching point or the curved area of the capillaries. Double staining for calponin or SMA and 3G5 demonstrated that pericytes of mid-capillaries expressed both calponin and 3G5, but not SMA. Since antibody 3G5 is not available for the paraffin sections, calponin should be a better pericyte marker than SMA or 3G5 and useful for immunohistochemical study to investigate tumor angiogenesis.