title: Carnosine decreased neuronal cell death through targeting glutamate system and astrocyte mitochondrial bioenergetics in cultured neuron/astrocyte exposed to OGD/recovery.
abstract: Previously, we showed that carnosine upregulated the expression level of glutamate transporter 1 (GLT-1), which has been recognized as an important participant in the astrocyte-neuron lactate shuttle (ANLS), with ischemic model in vitro and in vivo. This study was designed to investigate the protective effect of carnosine on neuron/astrocyte co-cultures exposed to OGD/recovery, and to explore whether the ANLS or any other mechanism contributes to carnosine-induced neuroprotection on neuron/astrocyte. Co-cultures were treated with carnosine and exposed to OGD/recovery. Cell death and the extracellular levels of glutamate and GABA were measured. The mitochondrial respiration and glycolysis were detected by Seahorse Bioscience XF96 Extracellular Flux Analyzer. Results showed that carnosine decreased neuronal cell death, increased extracellular GABA level, and abolished the increase in extracellular glutamate and reversed the mitochondrial energy metabolism disorder induced by OGD/recovery. Carnosine also upregulated the mRNA level of neuronal glutamate transporter EAAC1 at 2h after OGD. Dihydrokainate, a specific inhibitor of GLT-1, decreased glycolysis but it did not affect mitochondrial respiration of the cells, and it could not reverse the increase in mitochondrial OXPHOS induced by carnosine in the co-cultures. The levels of mRNAs for monocarboxylate transporter1, 4 (MCT1, 4), which were expressed in astrocytes, and MCT2, the main neuronal MCT, were significantly increased at the early stage of recovery. Carnosine only partly reversed the increased expression of astrocytic MCT1 and MCT4. These results suggest that regulating astrocytic energy metabolism and extracellular glutamate and GABA levels but not the ANLS are involved in the carnosine-induced neuroprotection.
authors.affiliation: Key Laboratory of Laboratory Medicine, Ministry of Education and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, PR China.
authors.forename: Li
authors.initials: L
authors.lastname: Ouyang
authors.affiliation: Key Laboratory of Laboratory Medicine, Ministry of Education and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, PR China.
authors.forename: Yueyang
authors.initials: Y
authors.lastname: Tian
authors.affiliation: Key Laboratory of Laboratory Medicine, Ministry of Education and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, PR China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Bao
authors.affiliation: Key Laboratory of Laboratory Medicine, Ministry of Education and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, PR China; Department of Pharmacology, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Huijuan
authors.initials: H
authors.lastname: Xu
authors.affiliation: Key Laboratory of Laboratory Medicine, Ministry of Education and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, PR China.
authors.forename: Jiaoyan
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Laboratory Medicine, Ministry of Education and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, PR China.
authors.forename: Bingyu
authors.initials: B
authors.lastname: Wang
authors.affiliation: Key Laboratory of Laboratory Medicine, Ministry of Education and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, PR China. Electronic address: yueshen-2002@163.com.
authors.forename: Yao
authors.initials: Y
authors.lastname: Shen
authors.affiliation: Department of Pharmacology, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, Zhejiang Province Key Laboratory of Neurobiology, College of Pharmaceutical Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, PR China.
authors.forename: Zhong
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Key Laboratory of Laboratory Medicine, Ministry of Education and Zhejiang Provincial Key Laboratory of Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325035, PR China.
authors.forename: Jianxin
authors.initials: J
authors.lastname: Lyu
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects*; D002336:Carnosine / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D015687:Cell Hypoxia / Q000187:drug effects*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D018920:Coculture Techniques; D004734:Energy Metabolism / Q000187:drug effects*; D005947:Glucose / Q000172:deficiency; D018698:Glutamic Acid / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000187:drug effects*; D010101:Oxygen Consumption / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D018698:Glutamic Acid; D002336:Carnosine; D005947:Glucose
keywords: Astrocyte-neuron lactate shuttle; Carnosine; Energy metabolism; GABA; Glutamate; OGD/recovery