Novel extracellular matrix structures in the neural stem cell niche capture the neurogenic factor fibroblast growth factor 2 from the extracellular milieu
Novel extracellular matrix structures in the neural stem cell niche capture the neurogenic factor fibroblast growth factor 2 from the extracellular milieu
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DOI：
10.1634/stemcells.2007-0082
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发表时间：
2007-09-01
期刊：
影响因子：
5.2
通讯作者：
Mercier, Frederic
中科院分区：
文献类型：
--
作者：
Kerever, Aurelien;Schnack, Jason;Mercier, Frederic
这种新的细胞外基质结构称为fractones，发现于侧脑室壁，主要的成人脑干细胞龛。通过电子显微镜，显示fractones接触神经干细胞和祖细胞（NSPC），这表明在神经发生中的作用。在这里，我们研究了增殖NSPC和fractones之间的空间关系，并确定了基本组件和fractones的第一个功能。使用溴脱氧尿苷（BrdU）在成年小鼠侧脑室壁的出生日期的细胞，我们发现大多数有丝分裂细胞旁边的碎片，虽然一些细胞出现在毛细血管旁边。像毛细血管基底膜，fractones免疫反应层粘连蛋白β 1和γ 1，胶原IV，巢蛋白，串珠素，但不是层粘连蛋白-α 1，在成年大鼠，小鼠和人类。有趣的是，N-硫酸乙酰肝素硫酸蛋白多糖（HSPG）的免疫反应仅限于fractone亚群和罕见的室管膜下毛细血管。BrdU和N-硫酸HSPG的双重免疫标记显示，优先有丝分裂的N-硫酸HSPG免疫反应性片段。为了确定是否N硫酸HSPG免疫反应内fractones反映了潜在的结合神经源性生长因子，我们确定了生物素化的成纤维细胞生长因子2（FGF-2）的结合位点原位冷冻切片，并在体内后，脑室内注射生物素化的FGF-2在成年大鼠或小鼠。两种结合试验均显示，在fractone亚群和罕见的室管膜下毛细血管上生物素化FGF-2。生物素化的FGF-2的结合是特异性的，并依赖于HSPG，如在体外和体内通过肝素酶抑制和N-硫酸HSPG免疫反应性的伴随消失所证明的。这些结果强烈表明，fractones促进生长因子的活性在神经干细胞龛。
The novel extracellular matrix structures called fractones are found in the lateral ventricle walls, the principal adult brain stem cell niche. By electron microscopy, fractones were shown to contact neural stem and progenitor cells (NSPC), suggesting a role in neurogenesis. Here, we investigated spatial relationships between proliferating NSPC and fractones and identified basic components and the first function of fractones. Using bromodeoxyuridine (BrdU) for birth-dating cells in the adult mouse lateral ventricle wall, we found most mitotic cells next to fractones, although some cells emerged next to capillaries. Like capillary basement membranes, fractones were immunoreactive for laminin beta 1 and gamma 1, collagen IV, nidogen, and perlecan, but not laminin-alpha 1, in the adult rat, mouse, and human. Intriguingly, N-sulfate heparan sulfate proteoglycan (HSPG) immunoreactivity was restricted to fractone subpopulations and infrequent subependymal capillaries. Double immunolabel for BrdU and N-sulfate HSPG revealed preferential mitosis next to N-sulfate HSPG inummoreactive fractones. To determine whether N sulfate HSPG immunoreactivity within fractones reflects a potential for binding neurogenic growth factors, we identified biotinylated fibroblast growth factor 2 (FGF-2) binding sites in situ on frozen sections, and in vivo after intracerebroventricular injection of biotinylated FGF-2 in the adult rat or mouse. Both binding assays revealed biotinylated FGF-2 on fractone subpopulations and on infrequent subependymal capillaries. The binding of biotinylated FGF-2 was specific and dependent upon HSPG, as demonstrated in vitro and in vivo by inhibition with heparatinase and by the concomitant disappearance of N-sulfate HSPG immunoreactivity. These results strongly suggest that fractones promote growth factor activity in the neural stem cell niche.