Wang Tongguang, Zhang Wei, Pei Zhong, Block Michelle, Wilson Belinda, Reece Jeffrey M, Miller David S, Hong Jau-Shyong
Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences/National Institutes of Health, Research Triangle Park,North Carolina, USA.
FASEB J. 2006 May;20(7):906-15. doi: 10.1096/fj.05-5053com.
It has been reported that extracellular matrix (ECM) molecules regulate monocyte activation by binding with a 67 kDa nonintegrin laminin receptor (LR). As microgliosis is a pivotal factor in propelling the progress of chronic neurodegeneration in the brain, we hypothesized that LR may regulate the microgliosis and subsequent neurotoxicity. Using 1-methyl-4-phenylpyridinium (MPP+) -treated C57 mice primary mesencephalic neuron-glia cultures as an in vitro Parkinson's disease (PD) model, we observed that MPP+ treatment increased LR expression only in the mixed neuron-glia but not in microglia-enriched or microglia-depleted cultures, indicating that MPP+-induced increase of LR expression is associated with neuron-microglia interaction. Using confocal microscopic examination, we found that LR was localized in the microglia, which were F4/80 positive. Treatment with the antibody (Ab) against LR (LR-Ab) or YIGSR, a synthetic pentapeptide inhibitor for LR, significantly attenuated the MPP+-increased F4/80 immunoreactivity (24 h) and dopaminergic (DA) neurotoxicity. LR-Ab also attenuated MPP+-increased microglial phagocytotic activity (48 h) and the superoxide production (4 days). Further study demonstrated that exogenous laminin (1-10 microg/ml) treatment induced microglial activation and DA neurotoxicity, in a dose-dependent manner, which was partially attenuated by the LR-Ab. We concluded that by regulating cell-ECM interaction, LR plays important roles in mediating microgliosis and subsequent DA neurotoxicity. Laminin is a potential ligand for activating this LR receptor. This study also suggests that laminin/LR is a potential target for developing new therapeutic drugs against neurodegenerative disorders such as PD.
据报道，细胞外基质（ECM）分子通过与67 kDa非整合素层粘连蛋白受体（LR）结合来调节单核细胞活化。由于小胶质细胞增生是推动大脑慢性神经退行性变进展的关键因素，我们推测LR可能调节小胶质细胞增生及随后的神经毒性。使用1-甲基-4-苯基吡啶离子（MPP+）处理的C57小鼠原代中脑神经元-胶质细胞培养物作为体外帕金森病（PD）模型，我们观察到MPP+处理仅在混合神经元-胶质细胞中增加LR表达，而在富含小胶质细胞或去除小胶质细胞的培养物中未增加，表明MPP+诱导的LR表达增加与神经元-小胶质细胞相互作用有关。通过共聚焦显微镜检查，我们发现LR定位于F4/80阳性的小胶质细胞中。用抗LR抗体（LR-Ab）或YIGSR（一种LR的合成五肽抑制剂）处理可显著减弱MPP+增加的F4/80免疫反应性（24小时）和多巴胺能（DA）神经毒性。LR-Ab还减弱了MPP+增加的小胶质细胞吞噬活性（48小时）和超氧化物产生（4天）。进一步研究表明，外源性层粘连蛋白（1-10微克/毫升）处理以剂量依赖方式诱导小胶质细胞活化和DA神经毒性，LR-Ab可部分减弱这种作用。我们得出结论，通过调节细胞-ECM相互作用，LR在介导小胶质细胞增生及随后的DA神经毒性中起重要作用。层粘连蛋白是激活该LR受体的潜在配体。本研究还表明，层粘连蛋白/LR是开发针对PD等神经退行性疾病的新治疗药物的潜在靶点。
