Rapid upregulation of fibroblast growth factor receptor 1 (flg) by rat photoreceptor cells after injury.
Rapid upregulation of fibroblast growth factor receptor 1 (flg) by rat photoreceptor cells after injury.
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发表时间：
2000-02
影响因子：
4.4
通讯作者：
S. Ozaki;M. Radeke;D. Anderson
中科院分区：
文献类型：
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作者：
S. Ozaki;M. Radeke;D. Anderson
目的探讨碱性成纤维细胞生长因子（bFGF）对退化或损伤的光感受器发挥神经保护作用的机制。方法采用共聚焦免疫荧光显微镜检测成年大鼠局灶性损伤或实验性视网膜脱离后bFGF及FGF受体1 （FGFR1）表达位点。在逆转录（RT）后，使用聚合酶链反应（PCR）分析FGFR1在单个光受体细胞中的免疫组织化学表达和转录水平。实时定量RT-PCR用于测量视网膜中FGFR1 mRNA水平在损伤或脱离后的变化。结果共聚焦免疫荧光观察显示，FGFR1在大鼠视网膜中的免疫反应性主要集中在感光细胞体的核周细胞质中。从游离的大鼠感光细胞中提取总RNA进行反转录，然后使用PCR扩增FGFR1 cDNA，验证了正常大鼠感光细胞中存在FGFR1转录物；相比之下，没有检测到bFGF转录的证据。总的来说，这些结果为FGFR1基因在大鼠光感受器原位表达提供了令人信服的证据。在实验性视网膜脱离或局灶性损伤后数小时内，外核层的FGFR1免疫反应性增加两倍，并持续至少7天；光感受器间基质中bFGF的免疫反应性也明显增加。western blot分析也证实了分离和损伤后FGFR1蛋白水平的增加。实时定量RT-PCR分析显示，FGFR1 mRNA在视网膜损伤/脱离后12小时内快速上调，但随后在24小时内下降到接近基线水平。结论：这些证据有力地表明，视网膜损伤和外源性bFGF注射引起的光感受器拯救作用至少部分是由光感受器细胞上调FGFR1介导的。
PURPOSE To determine the mechanism by which basic fibroblast growth factor (bFGF) exerts its neuroprotective effects on degenerating or injured photoreceptors. METHODS Confocal immunofluorescence microscopy was used to identify sites of bFGF and FGF receptor 1 (FGFR1) expression after focal injury or experimental retinal detachment in adult rats. FGFR1 expression was analyzed immunohistochemically and at the transcription level in single photoreceptor cells, after reverse transcription (RT), using the polymerase chain reaction (PCR). Real time quantitative RT-PCR was used to measure changes in FGFR1 mRNA levels in the retina in response to injury or detachment. RESULTS Confocal immunofluorescence observations showed that FGFR1 immunoreactivity in the rat retina is concentrated primarily in the perinuclear cytoplasm of photoreceptor cell bodies. Reverse transcription of total RNA derived from dissociated rat photoreceptor cells, followed by amplification of FGFR1 cDNA using the PCR, verified the presence of FGFR1 transcripts in normal rat photoreceptor cells; in contrast, no evidence of bFGF transcription was detected. Collectively, these results provide compelling evidence for FGFR1 gene expression by rat photoreceptors in situ. Within hours after experimental retinal detachment or focal injury, there is a twofold increase in FGFR1 immunoreactivity in the outer nuclear layer that persists for at least 7 days; a similar increase in bFGF immunoreactivity in the interphotoreceptor matrix is also apparent. This increase in FGFR1 protein levels after detachment and injury also was confirmed by western blot analysis. Real time quantitative RT-PCR analyses revealed that a rapid upregulation of FGFR1 mRNA occurred within 12 hours after retinal injury/detachment, but then declined to near baseline levels by 24 hours. CONCLUSIONS This body of evidence strongly suggests that the photoreceptor rescue effect elicited by retinal injury as well as by injection of exogenous bFGF is mediated, at least in part, by upregulation of the FGFR1 by the photoreceptor cells.