Anthocyanins abrogate glutamate-induced AMPK activation, oxidative stress, neuroinflammation, and neurodegeneration in postnatal rat brain.
Glutamate-induced excitotoxicity, oxidative damage, and neuroinflammation are believed to play an important role in the development of a number of CNS disorders. We recently reported that a high dose of glutamate could induce AMPK-mediated neurodegeneration in the postnatal day 7 (PND7) rat brain. Yet, the mechanism of glutamate-induced oxidative stress and neuroinflammation in the postnatal brain is not well understood. Here, we report for the first time the mechanism of glutamate-induced oxidative damage, neuroinflammation, and neuroprotection by polyphenolic anthocyanins in PND7.



PND7 rat brains, SH-SY5Y, and BV2 cells treated either alone with glutamate or in combination with anthocyanins and compound C were examined with Western blot and immunofluorescence techniques. Additionally, reactive oxygen species (ROS) assay and other ELISA kit assays were employed to know the therapeutic efficacy of anthocyanins against glutamate.



A single injection of glutamate to developing rats significantly increased brain glutamate levels, activated and phosphorylated AMPK induction, and inhibited nuclear factor-E2-related factor 2 (Nrf2) after 2, 3, and 4 h in a time-dependent manner. In contrast, anthocyanin co-treatment significantly reduced glutamate-induced AMPK induction, ROS production, neuroinflammation, and neurodegeneration in the developing rat brain. Most importantly, anthocyanins increased glutathione (GSH and GSSG) levels and stimulated the endogenous antioxidant system, including Nrf2 and heme oxygenase-1 (HO-1), against glutamate-induced oxidative stress. Interestingly, blocking AMPK with compound C in young rats abolished glutamate-induced neurotoxicity. Similarly, all these experiments were replicated in SH-SY5Y cells by silencing AMPK with siRNA, which suggests that AMPK is the key mediator in glutamate-induced neurotoxicity.



Here, we report for the first time that anthocyanins can potentially decrease glutamate-induced neurotoxicity in young rats. Our work demonstrates that glutamate is toxic to the developing rat brain and that anthocyanins can minimize the severity of glutamate-induced neurotoxicity in an AMPK-dependent manner.
Neuroscience Pioneer Research Center, Department of Biology and Applied Life Science (BK21), College of Natural Sciences, Gyeongsang National University, Jinju, 660-701, Republic of Korea.
Shahid Ali
SA
Shah
Neuroscience Pioneer Research Center, Department of Biology and Applied Life Science (BK21), College of Natural Sciences, Gyeongsang National University, Jinju, 660-701, Republic of Korea.
Faiz Ul
FU
Amin
Neuroscience Pioneer Research Center, Department of Biology and Applied Life Science (BK21), College of Natural Sciences, Gyeongsang National University, Jinju, 660-701, Republic of Korea.
Mehtab
M
Khan
Neuroscience Pioneer Research Center, Department of Biology and Applied Life Science (BK21), College of Natural Sciences, Gyeongsang National University, Jinju, 660-701, Republic of Korea.
Muhammad Noman
MN
Abid
Neuroscience Pioneer Research Center, Department of Biology and Applied Life Science (BK21), College of Natural Sciences, Gyeongsang National University, Jinju, 660-701, Republic of Korea.
Shafiq Ur
SU
Rehman
Neuroscience Pioneer Research Center, Department of Biology and Applied Life Science (BK21), College of Natural Sciences, Gyeongsang National University, Jinju, 660-701, Republic of Korea.
Tae Hyun
TH
Kim
Neuroscience Pioneer Research Center, Department of Biology and Applied Life Science (BK21), College of Natural Sciences, Gyeongsang National University, Jinju, 660-701, Republic of Korea.
Min Woo
MW
Kim
Neuroscience Pioneer Research Center, Department of Biology and Applied Life Science (BK21), College of Natural Sciences, Gyeongsang National University, Jinju, 660-701, Republic of Korea. mokim@gsnu.ac.kr.
Myeong Ok
MO
Kim
D055372:AMP-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000831:Animals, Newborn; D000872:Anthocyanins / Q000494:pharmacology* / Q000627:therapeutic use*; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use; D002461:Cell Line, Transformed; D051546:Cyclooxygenase 2 / Q000378:metabolism; D004660:Encephalitis / Q000139:chemically induced / Q000188:drug therapy*; D004789:Enzyme Activation / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects; D005973:Glutamine / Q000633:toxicity; D006801:Humans; D009410:Nerve Degeneration / Q000139:chemically induced / Q000188:drug therapy*; D009447:Neuroblastoma / Q000473:pathology; D018384:Oxidative Stress / Q000187:drug effects*; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects
D000872:Anthocyanins; D000975:Antioxidants; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; D005973:Glutamine; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat; D055372:AMP-Activated Protein Kinases
AMPK; Anthocyanins; Glutamate; Neurotoxicity; Nrf2; ROS