A Novel Tetramethylpyrazine Derivative Prophylactically Protects against Glutamate-Induced Excitotoxicity in Primary Neurons through the Blockage of N-Methyl-D-aspartate Receptor

Abstract

The over-activation of NMDA receptor via the excessive glutamate is believed to one of the most causal factors associated with Alzheimer’s disease (AD), a progressive neurodegenerative brain disorder. Molecules that could protect against glutamate-induced neurotoxicity may hold therapeutic values for treating AD. Herein, the neuroprotective mechanisms of dimeric DT-010, a novel derivative of naturally occurring danshensu and tetramethylpyrazine, were investigated using primary rat cerebellar granule neurons (CGNs) and hippocampal neurons. It was found that DT-010 (3–30 μM) markedly prevented excitotoxicity of CGNs caused by glutamate, as evidenced by the promotion of neuronal viability as well as the reversal of abnormal morphological changes. While its parent molecules did not show any protective effects even when their concentration reached 50 μM. Additionally, DT-010 almost fully blocked intracellular accumulation of reactive oxygen species caused by glutamate and exogenous oxidative stimulus. Moreover, Western blot results demonstrated that DT-010 remarkably attenuated the inhibition of pro-survival PI3K/Akt/GSK3β pathway caused by glutamate. Ca2+ imaging with Fluo-4 fluorescence analysis further revealed that DT-010 greatly declined glutamate-induced increase in intracellular Ca2+. Most importantly, with the use of whole-cell patch clamp electrophysiology, DT-010 directly inhibited NMDA-activated whole-cell currents in primary hippocampal neurons. Molecular docking simulation analysis further revealed a possible binding mode that inhibited NMDA receptor at the ion channel, showing that DT-010 favorably binds to Asn602 of NMDA receptor via arene hydrogen bond. These results suggest that DT-010 could be served as a novel NMDA receptor antagonist and protect against glutamate-induced excitotoxicity from blocking the upstream NMDA receptors to the subsequent Ca2+ influx and to the downstream GSK3β cascade.

<p>Tetramethylpyrazine attenuated bupivacaine-induced neurotoxicity in SH-SY5Y cells through regulating apoptosis, autophagy and oxidative damage</p>

“…9 Several studies have shown that TET exhibited strong protective effects against neurotoxicity in Alzheimer's disease and Parkinson's disease. 12,13 Hu et al studied that TET derivative could protect primary neurons against glutamate-induced excitotoxicity. 12 Moreover, TET also demonstrated a potent neuroprotective role in MPP+-induced neuro cells via activating transcription factor MEF2D.…”

“…12,13 Hu et al studied that TET derivative could protect primary neurons against glutamate-induced excitotoxicity. 12 Moreover, TET also demonstrated a potent neuroprotective role in MPP+-induced neuro cells via activating transcription factor MEF2D. 13 In spite of many reports indicating that TET plays a protective effect against neurotoxicity, little is known about the effect of TET on BUP-induced neurotoxicity.…”

Production of tetra-methylpyrazine using engineered Corynebacterium glutamicum

“…These observations highlight the importance of considering both the specific heterologous gene pathway as well as potential feedback on the chosen microbial host. With high titers of TMP, these C. glutamicum strains will facilitate rapid evaluation of TMP derivatives using candidate enzyme libraries to be expressed in a gram-positive microbial host (Hu et al., 2018; Stankevičiūtė et al., 2016; Zhang et al., 2016). Being able to produce >1 ​g/L quantities of many TMP derivatives will unlock the potential of this emerging molecule for a broader spectrum of applications.…”

Oxidative stress accelerates synaptic glutamate dyshomeostasis and NMDARs disorder during methylmercury‐induced neuronal apoptosis in rat cerebral cortex

“…With the help of glutamine synthetase (GS), Glu in astrocytes could be transformed to glutamine (Gln). Studies have suggested that inhibition of astrocytic Glu uptake may lead to the increase of Glu concentrations in the synaptic cleft, contributing to Glu‐mediated excitotoxicity including activation of the Glu receptors particularly of N ‐methyl‐ d ‐aspartic acid receptors (NMDARs), and the following of excessive Ca 2+ influx into neurons through ionic channels . Previous studies have shown that specific blockade of NMDARs largely blocks the toxicity of Glu under in vivo or in vitro conditions .…”