Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Hosur Road, Bangalore, 560 029, India.
Mol Neurobiol. 2015;51(3):995-1007. doi: 10.1007/s12035-014-8757-y. Epub 2014 Jun 1.
Vascular endothelial growth factor (VEGF), the well-known angiogenic factor is both neurotrophic and neuroprotective. Altered VEGF signalling is implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS), a fatal degenerative disease of motor neurons. We have shown earlier that VEGF protects NSC-34 motor neuronal cell line, when exposed to cerebrospinal fluid (CSF) from sporadic ALS patients (ALS-CSF). Here, we have investigated the consequences of ALS-CSF and VEGF supplementation on the VEGFR2 receptor and endogenous VEGF expression. ALS-CSF caused significant down-regulation of VEGFR2 as well as the Calbindin-D28K levels, but not endogenous VEGF. Exogenous supplementation restored the depletion of VEGFR2 and Calbindin-D28K with a concomitant up-regulation of endogenous VEGF. The up-regulated caspase 3 in the ALS-CSF group was reinstated to basal levels along with a significant reduction in the number of TUNEL-positive cells. Electron photomicrographs of ALS-CSF-exposed cells divulged presence of cytoplasmic vacuoles alongside severe damage to organelles like mitochondria, endoplasmic reticulum, etc. Substantial recovery of most of the damaged organelles was noted in response to VEGF supplementation. While the enhancement in endogenous VEGF levels highlights the autocrine functions, the up-regulation of VEGFR2 receptor emphasizes the paracrine functions of VEGF in modulating its neuroprotective effect against ALS-CSF. The revival of cellular organellar structure, increased calbindin expression and enhanced survival in response to VEGF supplementation consolidates the opinion that VEGF indeed has a therapeutic potential in sporadic ALS.
血管内皮生长因子（VEGF）是一种众所周知的血管生成因子，具有神经营养和神经保护作用。VEGF 信号的改变与肌萎缩侧索硬化症（ALS）的发病机制有关，ALS 是一种致命的运动神经元退行性疾病。我们之前已经表明，VEGF 可以保护 NSC-34 运动神经元细胞系，当暴露于来自散发性 ALS 患者的脑脊液（ALS-CSF）时。在这里，我们研究了 ALS-CSF 和 VEGF 补充对 VEGFR2 受体和内源性 VEGF 表达的影响。ALS-CSF 导致 VEGFR2 以及钙结合蛋白-D28K 水平的显著下调，但不影响内源性 VEGF。外源性补充恢复了 VEGFR2 和钙结合蛋白-D28K 的耗竭，同时伴有内源性 VEGF 的上调。ALS-CSF 组中上调的 caspase 3 恢复到基础水平，同时 TUNEL 阳性细胞的数量显著减少。暴露于 ALS-CSF 的细胞的电子显微镜照片显示细胞质空泡的存在，以及线粒体、内质网等细胞器的严重损伤。VEGF 补充后，大多数受损细胞器得到了显著的恢复。虽然内源性 VEGF 水平的提高突出了其自分泌功能，但是 VEGFR2 受体的上调强调了 VEGF 在调节其对 ALS-CSF 的神经保护作用中的旁分泌功能。细胞细胞器结构的恢复、钙结合蛋白表达的增加以及对 VEGF 补充的存活增加，证实了 VEGF 确实具有治疗散发性 ALS 的潜力。
