Rieger D K, Navarro E, Buendia I, Parada E, González-Lafuente L, Leon R, Costa A P, Heinrich I A, Nascimento K S, Cavada B S, Lopez M G, Egea J, Leal R B
Programa de Pós-graduação em Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, Brazil.
Departamento de Bioquímica, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, SC, 88040-900, Brazil.
Neurochem Res. 2017 Feb;42(2):347-359. doi: 10.1007/s11064-016-2078-7. Epub 2016 Oct 17.
Lectins are proteins that bind cellular glycans and can modulate various neuronal functions. We have evaluated the neuroprotective effect of ConBr, a lectin purified from the seeds of Canavalia brasiliensis in a model of rat organotypic hippocampal cultures (OHCs) exposed to oxygen and glucose deprivation (OGD). OGD for 15 min followed by 24 h re-oxygenation significantly increased cell death, caused mitochondrial depolarization and increased reactive oxygen species (ROS) in CA1 region of OHCs. ConBr (0.1 μg/mL) added during the re-oxygenation period counteracted cell death, mitochondrial depolarization and overproduction of ROS induced by OGD. Moreover, ConBr restored the levels of Akt and ERK1 phosphorylation that were reduced by OGD. Modulation of intracellular Ca by ConBr was evaluated in isolated hippocampal neurons loaded with the fluorescent calcium dye Fluo-4/AM. ConBr (0.1 and 1 µg/mL) reduced by 25-30 % the Ca increment induced by 70 mM K. A sub effective concentration of ConBr (0.01 µg/mL) together with a sub effective concentration of the L-type calcium channel antagonist nifedipine (0.3 µM) conferred a synergic neuroprotective effect in OHCs subjected to OGD. In conclusion, ConBr provides OHCs neuroprotection against OGD. The mechanism was not fully addressed but it may involve modulation of L-type voltage-gated Ca channels by ConBr.
凝集素是一类能结合细胞聚糖并可调节多种神经元功能的蛋白质。我们评估了从巴西刀豆种子中纯化得到的凝集素ConBr在大鼠器官型海马培养物（OHCs）暴露于氧糖剥夺（OGD）模型中的神经保护作用。15分钟的OGD后再进行24小时复氧，显著增加了细胞死亡，导致线粒体去极化，并增加了OHCs海马CA1区的活性氧（ROS）。在复氧期添加ConBr（0.1μg/mL）可抵消OGD诱导的细胞死亡、线粒体去极化和ROS的过量产生。此外，ConBr恢复了被OGD降低的Akt和ERK1磷酸化水平。在加载了荧光钙染料Fluo-4/AM的分离海马神经元中评估了ConBr对细胞内钙的调节作用。ConBr（0.1和1μg/mL）使70mM钾诱导的钙增加降低了25 - 30%。亚有效浓度的ConBr（0.01μg/mL）与亚有效浓度的L型钙通道拮抗剂硝苯地平（0.3μM）一起，在经受OGD的OHCs中发挥了协同神经保护作用。总之，ConBr为OHCs提供了针对OGD的神经保护。其机制尚未完全阐明，但可能涉及ConBr对L型电压门控钙通道的调节。
