title: Neuroprotection against glutamate-induced excitotoxicity and induction of neurite outgrowth by T-006, a novel multifunctional derivative of tetramethylpyrazine in neuronal cell models.
abstract: Alzheimer's disease is a progressive neurodegenerative disorder, characterized by irreversible impairment of memory and cognitive function. The exact causes of Alzheimer's disease still remain unclear and current single target drugs could only offer limited therapeutic effect to the patients. We have previously reported that T-006, a promising anti-Alzheimer's compound derived from Chinese medicinal component tetramethylpyrazine, might protect neurons through inhibiting the overproduction of intracellular reactive oxygen species (ROS) and reactive nitrogen species (RNS). In this study, we further investigated the neuroprotective effects, as well as the molecular pathways involved, of T-006 against glutamate-induced excitotoxicity in rat cerebellar granule neurons (CGNs). T-006 was also found to promote neuronal differentiation in both PC12 cells and primary cultured rat cortical neurons. The results showed that the pretreatment of T-006 (0.01-1 μM) might prevent glutamate-induced neuronal loss in a concentration-dependent manner. T-006 is found to inhibit the over-activation of NMDAR and ensued calcium overload caused by glutamate. The following activation of phosphorylated extracellular signal-regulated kinase (ERK) were also abolished. Moreover, T-006 concurrently prevented the suppression of phosphorylated protein kinase B (Akt) and glycogen synthase kinase 3β (GSK3β). T-006 was also found to promote neurite outgrowth in PC12 cells and primary cortical neurons. In our study, T-006 (0.1-3 μM) dose-dependently stimulated neurite outgrowth in PC12 cells and the efficacy was comparable to nerve growth factor (NGF). Moreover, co-treatment of T-006 and NGF revealed that T-006 could robustly potentiate the NGF-induced neuritogenesis. Further signal transduction studies indicated that T-006 rapidly up-regulated phosphorylation of ERK but did not activate tyrosine kinase receptor A (Trk A). These findings offer deeper understanding of the anti-neurodegenerative activity of T-006 and provide insight into its possible therapeutic potential for AD treatment in light of the multipotent nature of T-006.
authors.affiliation: Department of Applied Biology and Chemical Technology, Institute of Modern Chinese Medicine, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.
authors.forename: Daping
authors.initials: D
authors.lastname: Xu
authors.affiliation: Institute of New Drug Research and Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, Guangdong, China.
authors.forename: Haiyun
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of Applied Biology and Chemical Technology, Institute of Modern Chinese Medicine, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.
authors.forename: Shinghung
authors.initials: S
authors.lastname: Mak
authors.affiliation: Department of Applied Biology and Chemical Technology, Institute of Modern Chinese Medicine, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China.
authors.forename: Shengquan
authors.initials: S
authors.lastname: Hu
authors.affiliation: Division of Life Science, Center for Chinese Medicine and State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
authors.forename: Karl W K
authors.initials: KWK
authors.lastname: Tsim
authors.affiliation: State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Av. Padre Tomás Pereira S.J., Taipa, Macao 999078, China.
authors.forename: Yuanjia
authors.initials: Y
authors.lastname: Hu
authors.affiliation: Institute of New Drug Research and Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, Guangdong, China.
authors.forename: Yewei
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Institute of New Drug Research and Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, Guangdong, China.
authors.forename: Gaoxiao
authors.initials: G
authors.lastname: Zhang
authors.affiliation: Institute of New Drug Research and Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, Guangdong, China.
authors.forename: Yuqiang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Institute of New Drug Research and Guangdong Province Key Laboratory of Pharmacodynamic Constituents of Traditional Chinese Medicine, College of Pharmacy, Jinan University, Guangzhou 510632, Guangdong, China.
authors.forename: Zaijun
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: Department of Applied Biology and Chemical Technology, Institute of Modern Chinese Medicine, The Hong Kong Polytechnic University, Hung Hom, Hong Kong, China. Electronic address: bcyfhan@polyu.edu.hk.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Han
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity; D018698:Glutamic Acid / Q000633:toxicity*; D006835:Hydrazones / Q000737:chemistry / Q000494:pharmacology*; D000071446:Neuronal Outgrowth / Q000187:drug effects / Q000502:physiology*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D000066829:Neuroprotection / Q000187:drug effects / Q000502:physiology*; D016716:PC12 Cells; D011719:Pyrazines / Q000737:chemistry / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D018690:Excitatory Amino Acid Agonists; D006835:Hydrazones; D011719:Pyrazines; C000608515:T-006 compound; D018698:Glutamic Acid; C017953:tetramethylpyrazine
keywords: Alzheimer's disease; Excitotoxicity; Neurite outgrowth; Neuroprotection; Tetramethylpyrazine derivative