title: Tissue kallikrein alleviates glutamate-induced neurotoxicity by activating ERK1.
abstract: Glutamate-induced neurotoxicity consequent to N-methyl-D-aspartic acid (NMDA) and 2-amino-3-(3-hydroxy-5-methyl-isoxazol-4-yl) propionic acid (AMPA) receptor activation underlies the pathogenesis of a wide range of central nervous system disorders, including brain ischemia. Prevention of ischemia/reperfusion (I/R)-induced neuronal injury has long been regarded as an effective therapeutic strategy for ischemia. Human tissue kallikrein (TK) gene transfer has been shown to protect neurons against cerebral I/R-induced apoptosis and oxidative stress, via activation of the brandykinin B2 receptor (B2R). However, little is known about the role of TK on glutamate-induced neurotoxicity. Here we report that pretreatment of cultured cortical neurons with TK largely prevented glutamate-induced morphological changes and cell death. We found that TK pretreatment alleviated glutamate-induced oxidative stress by inhibiting neuronal nitric oxide synthase (nNOS) activity, thereby reducing the generation of nitric oxide (NO) and reactive oxygen species (ROS). Blockage of NMDA and AMPA receptors by their specific antagonists MK801 and CNQX had effects similar to those of TK administration. Furthermore, we found that the extracellular signal-regulated kinase 1/2 cascade (ERK1/2), particularly ERK1, and nuclear factor-kappaB (NF-kappaB) were involved in TK neuroprotection against glutamate-induced neurotoxicity. TK pretreatment activated ERK1 and NF-kappaB, leading to enhanced expression of brain-derived neurotrophic factor (BDNF) mRNA and antiapoptotic gene Bcl-2 protein. Collectively, these findings demonstrate that TK attenuates glutamate-induced apoptosis through an intracellular signaling pathway including activation of B2R, ERK1/2, and NF-kappaB and up-regulation of BDNF and Bcl-2 expression. Thus, TK represents a promising therapeutic strategy for ischemic stroke.
authors: Department of Neurology, Jinling Hospital, Nanjing University School of Medicine, Nanjing, People's Republic of China.
authors: Ling
authors: L
authors: Liu
authors: Renliang
authors: R
authors: Zhang
authors: Kui
authors: K
authors: Liu
authors: Houguang
authors: H
authors: Zhou
authors: Yuping
authors: Y
authors: Tang
authors: Jinjin
authors: J
authors: Su
authors: Xiaoyan
authors: X
authors: Yu
authors: Xuelian
authors: X
authors: Yang
authors: Min
authors: M
authors: Tang
authors: Qiang
authors: Q
authors: Dong
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000704:Analysis of Variance; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D019610:Cytoprotection; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018698:Glutamic Acid / Q000633:toxicity*; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009569:Nitric Oxide / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D018091:Receptors, AMPA / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D020840:Tissue Kallikreins / Q000008:administration & dosage / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D018691:Excitatory Amino Acid Antagonists; D016328:NF-kappa B; D019253:Proto-Oncogene Proteins c-bcl-2; D017382:Reactive Oxygen Species; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; D009569:Nitric Oxide; D018698:Glutamic Acid; D016291:Dizocilpine Maleate; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D052248:Nitric Oxide Synthase Type I; D048052:Mitogen-Activated Protein Kinase 3; D020840:Tissue Kallikreins