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Zhou J, Zhang Z, Yang Y, Liao F, Zhou P, Wang Y, Zhang H, Jiang H, Alinejad T, Shan G, Wu S. Deletion of serine racemase reverses neuronal insulin signaling inhibition by amyloid-β oligomers. J Neurochem 2022; 163:8-25. [PMID: 35839294 DOI: 10.1111/jnc.15664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Revised: 04/26/2022] [Accepted: 07/06/2022] [Indexed: 11/27/2022]
Abstract
Dysregulation of insulin signaling in the Alzheimer's (AD) brain has been extensively reported. Serine racemase(SR) modulates insulin secretion in pancreatic islets. Similarly, we wonder whether or not SR regulates insulin synthesis and secretion in neurons, thereby modulating insulin signaling in the AD brain. Srr-knockout (Srr-/- ) mice generated with the CRISPR/Cas9 technique were used. Using immunofluorescence and fluorescence in situ hybridization, the levels of insulin protein and insulin(ins2) mRNA significantly increased in the hippocampal but not in the hypothalamic sections of Srr-/- mice compared with WT mice. Using real-time quantitative PCR, ins2 mRNA from primary hippocampal neuronal cultures of Srr-/- mice significantly increased compared with the cultured neurons from WT mice. Notably, the secretion of proinsulin C-peptide increased in Srr-/- neurons relative to WT neurons. By examining the membrane fractional proteins with immunoblotting, Srr-/- neurons retained ATP-dependent potassium channel on plasmalemma and correspondingly contained higher levels of p-AMPK. Under treatment by Aβ42, the phosphorylation levels of insulin receptor substrate at serine 616,636 (p-IRS1ser616,636 ) were significantly lower whereas p-AKT308 and p-AKT473 were higher in Srr-/- neurons, compared with WT neurons, respectively. The phosphorylated form of c-Jun N-terminal kinase decreased in the cultured Srr-/- neurons relative to the WT neurons upon Aβ42 treatment. In contrast, the phosphorylated protein kinase R remained at the same levels. Further, reactive oxygen species reduced in the cultured Srr-/- neurons under Aβ42 treatment relative to the WT neurons. Altogether, our study indicated that Srr deletion promoted insulin synthesis and secretion of proinsulin C-peptide, thereby reversing insulin resistance by Aβ42. This study suggests that targeting the neuronal SR may be utilized to enhance insulin signaling which is inhibited at the early stage of the AD brain.
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Affiliation(s)
- Jing Zhou
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Zhejiang, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Zhejiang, P.R. China
| | - Zhiwen Zhang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Zhejiang, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Zhejiang, P.R. China
| | - Yuanhong Yang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Zhejiang, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Zhejiang, P.R. China
| | - Fei Liao
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Zhejiang, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Zhejiang, P.R. China
| | - Piansi Zhou
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Zhejiang, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Zhejiang, P.R. China
| | - Yan Wang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Zhejiang, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Zhejiang, P.R. China
| | - He Zhang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Zhejiang, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Zhejiang, P.R. China.,College of Life and Environmental Sciences, Wenzhou University, Zhejiang, People's Republic of China
| | - Haiyan Jiang
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Zhejiang, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Zhejiang, P.R. China
| | - Tahereh Alinejad
- The Key Laboratory of Interventional Pulmonology of Zhejiang Province, Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital of Wenzhou Medical University, South Baixiang, Ouhai District, Zhejiang, China
| | - Ge Shan
- CAS Key Laboratory of Innate Immunity and Chronic Disease, CAS Center for Excellence in Molecular Cell Science, School of Life Sciences, University of Science and Technology of China, Hefei, Anhui Province, China
| | - Shengzhou Wu
- School of Optometry and Ophthalmology and the Eye Hospital, Wenzhou Medical University, Zhejiang, P.R. China.,State Key Laboratory of Optometry, Ophthalmology, and Visual Science, Zhejiang, P.R. China
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Yoshihisa Y, Rehman MU, Nakagawa M, Matsukuma S, Makino T, Mori H, Shimizu T. Inflammatory cytokine-mediated induction of serine racemase in atopic dermatitis. J Cell Mol Med 2018; 22:3133-3138. [PMID: 29566294 PMCID: PMC5980141 DOI: 10.1111/jcmm.13592] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 02/05/2018] [Indexed: 01/15/2023] Open
Abstract
Serine racemase (SR) is an enzyme that catalyses the synthesis of d‐serine, an endogenous coagonist for N‐methyl‐D‐aspartate (NMDA)‐type glutamate receptor in the central nervous system. Our previous study demonstrated that SR was expressed in the epidermis of wild‐type (WT) mice but not in SR knockout (KO) mice. In addition, SR immune‐reactivity was only found in the granular and cornified layers of the epidermis in WT mice. These findings suggested that SR is involved in the differentiation of epidermal keratinocytes and the formation of the skin barrier. However, its role in skin barrier dysfunction such as atopic dermatitis (AD) remains elusive. AD is a chronic inflammatory disease of skin, and the clinical presentation of AD has been reported to be occasionally associated with psychological factors. Therefore, this study examined the content of d‐serine in stratum corneum in AD patients and healthy controls using a tape‐stripping method. Skin samples were collected from the cheek and upper arm skin of AD patient's lesion and healthy individuals. The d‐serine content was significantly increased in the involved skin of AD in comparison with healthy individuals. An immunohistochemical analysis also revealed an increased SR expression in the epidermis of AD patients. Furthermore, the SR expression in cultured human keratinocytes was significantly increased by the stimulation with tumour necrosis factor ‐α or macrophage migration inhibitory factor. Taken together, these findings suggest that d‐serine expressed particularly strongly in AD lesional skin and that the SR expression in the keratinocytes is linked to inflammatory cytokines.
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Affiliation(s)
- Yoko Yoshihisa
- Department of Dermatology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Mati Ur Rehman
- Department of Radiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Maho Nakagawa
- Advanced Technology Research Center, FANCL Research Institute, Yokohama, Japan
| | - Shoko Matsukuma
- Advanced Technology Research Center, FANCL Research Institute, Yokohama, Japan
| | - Teruhiko Makino
- Department of Dermatology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Hisashi Mori
- Department of Molecular Neuroscience, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
| | - Tadamichi Shimizu
- Department of Dermatology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan
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Zhang H, Song L, Chang Y, Wu M, Kuang X, Jiang H, Wu S. Potential deficit from decreased cerebellar granule cell migration in serine racemase-deficient mice is reversed by increased expression of GluN2B and elevated levels of NMDAR agonists. Mol Cell Neurosci 2017; 85:119-126. [PMID: 28939329 DOI: 10.1016/j.mcn.2017.09.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2017] [Revised: 08/27/2017] [Accepted: 09/14/2017] [Indexed: 12/19/2022] Open
Abstract
Inward migration of cerebellar granule cells (CGCs) after birth is critical for lamination in the cerebellar cortex. N-methyl-d-aspartate (NMDA) subtype of glutamate receptor (NMDAR) tethering CGCs into Bergmann glial fibers mediates the inward movement during the glial-dependent migratory phase. Activation of NMDAR depends on simultaneous binding of the GluN2 subunit by glutamate, and of the GluN1 subunit by d-serine or glycine; d-serine is believed to be an endogenous ligand of NMDAR. We hypothesized that lamination of the cerebellar cortex may be compromised in Srr (the gene for serine racemase (SR)) mutated mice (Srrnull) because of significantly low levels of d-serine per se. Indeed, the external germinal cell layer (EGL) in Srrnull was thicker than in sibling wild-type (WT) mice on postnatal day7 (P7), which accords with decreased CGC migration in Srrnull mice. However, the cerebellar laminar structure in Srrnull mice was normal on P12 and later. Feeding d-serine to pregnant mice abrogated the increased EGL thickness in Srrnull mice on P7. To determine the underlying mechanism of abnormal laminar structure during cerebellar development in Srrnull mice, we examined NMDAR subunits and their ligands. We found increased GluN2B on P10 and increased glycine during P7-12 in the cerebellar homogenates from Srrnull mice compared with the corresponding values from sibling WT mice. In summary, the study revealed how the potential defect in early cerebellar development caused by Srr mutation is circumvented by a compensatory mechanism. This knowledge advances understanding of the adaptation of cerebellar development under the condition of Srr mutation.
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Affiliation(s)
- He Zhang
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, P.R. China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, P.R. China
| | - Liping Song
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, P.R. China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, P.R. China
| | - Yuhua Chang
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, P.R. China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, P.R. China
| | - Mengjuan Wu
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, P.R. China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, P.R. China
| | - Xiuli Kuang
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, P.R. China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, P.R. China
| | - Haiyan Jiang
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, P.R. China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, P.R. China
| | - Shengzhou Wu
- School of Optometry and Ophthalmolgy and the Eye Hospital, Wenzhou Medical University, P.R. China; State Key Laboratory of Optometry, Ophthalmology, and Visual Science, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, P.R. China.
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Jiang H, Wang X, Zhang H, Chang Y, Feng M, Wu S. Loss-of-function mutation of serine racemase attenuates excitotoxicity by intravitreal injection of N
-methyl-D-aspartate. J Neurochem 2015; 136:186-93. [PMID: 26485193 DOI: 10.1111/jnc.13400] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 09/07/2015] [Accepted: 10/12/2015] [Indexed: 02/01/2023]
Affiliation(s)
- Haiyan Jiang
- School of Optometry and Ophthalmology and the Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| | - Xianwei Wang
- School of Optometry and Ophthalmology and the Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| | - He Zhang
- School of Optometry and Ophthalmology and the Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| | - Yuhua Chang
- School of Optometry and Ophthalmology and the Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| | - Meiling Feng
- School of Optometry and Ophthalmology and the Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
| | - Shengzhou Wu
- School of Optometry and Ophthalmology and the Eye Hospital; Wenzhou Medical University; Wenzhou Zhejiang China
- State Key Laboratory Cultivation Base and Key Laboratory of Vision Science; Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry; Wenzhou Zhejiang China
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Zhang H, Kuang XL, Chang Y, Lu J, Jiang H, Wu S. Reduced serine racemase expression in aging rat cerebellum is associated with oxidative DNA stress and hypermethylation in the promoter. Brain Res 2015; 1629:221-30. [PMID: 26505919 DOI: 10.1016/j.brainres.2015.10.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 10/16/2015] [Accepted: 10/17/2015] [Indexed: 12/16/2022]
Abstract
Regulation of serine racemase (SR) occurs at transcriptional and translational levels; post-translational modification, cytosolic distribution as well as allosteric effect regulate SR activity. In this study, we report a new route of SR regulation, i.e. oxidative stress and hypermethylation of the srr (gene of SR) promoter correlate with its reduced transcription in aging rat cerebella. We first showed that the mRNA and protein level of srr were decreased in the homogenates of rat cerebellum at age 12 months compared with the counterparts from age 20 days. The reduction of SR protein level in aging cerebella was evidenced by decreased immunostaining observed in the cell body of granule cells or Purkinje cells. Staining for 8-hydroxy-2'-deoxyguanosine (8-OHdG), a marker for oxidative stress to DNA, was much stronger in granule cell or Purkinje cell nuclei from rat cerebella at 12 months compared with staining at 20 days. We further detected srr promoter hypermethylation at 12 months compared with that at 20 days by use of bisulfite sequencing PCR, coinciding with elevated protein levels of DNA methyltransferase 1 (DNMT1) in homogenates of aging cerebella. In vitro, we demonstrated that chronic treatment with the oxidant, menadione (VK3), reduced srr mRNA levels, which was reversed by the DNA demethylating agent 5-Aza-dC-2'-deoxycytidine (5-Aza-dC) in primary cerebellar granule cell cultures. Together, the in vivo and ex vivo results suggest that oxidative DNA stress and srr promoter hypermethylation are associated with reduced srr gene transcription and corresponding reduced protein expression in aging cerebella.
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Affiliation(s)
- He Zhang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China; State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China
| | - Xiu-Li Kuang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China; State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China
| | - Yuhua Chang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China; State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China
| | - Jinfang Lu
- Department of Genetics, Dingli Clinical Medical School, Wenzhou Medical University, Key Laboratory of Birth Defects, Wenzhou, Zhejiang, China
| | - Haiyan Jiang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China; State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China
| | - Shengzhou Wu
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China; State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, China.
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6
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Jiang H, Fang J, Wu B, Yin G, Sun L, Qu J, Barger SW, Wu S. Overexpression of serine racemase in retina and overproduction of D-serine in eyes of streptozotocin-induced diabetic retinopathy. J Neuroinflammation 2011; 8:119. [PMID: 21939517 PMCID: PMC3207970 DOI: 10.1186/1742-2094-8-119] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2011] [Accepted: 09/22/2011] [Indexed: 11/12/2022] Open
Abstract
Background Recent data indicate that inflammatory mechanisms contribute to diabetic retinopathy (DR). We have determined that serine racemase (SR) expression is increased by inflammatory stimuli including liposaccharide (LPS), amyloid β-peptide (A-beta), and secreted amyloid precursor protein (sAPP); expression is decreased by the anti-inflammatory drug, dexamethasone. We tested possibility that SR and its product, D-serine, were altered in a rat model of DR. Methods Intraperitoneal injection of streptozotocin (STZ; 70 mg/kg body weight) to Sprague-Dawley rats produced type-I diabetic mellitus (fasting blood sugar higher than 300 mg/dL). At 3 and 5 months after STZ or saline injection, retinas from some rats were subjected to cryosectioning for immunofluorescent analysis of SR and TUNEL assay of apoptosis. Retinal homogenates were used to detect SR levels and Jun N-terminal kinase (JNK) activation by immunoblotting. Aqueous humor and retina were also collected to assay for neurotransmitters, including glutamate and D-serine, by reverse-phase HPLC. Results Compared to saline-injected rats, STZ-injected (diabetic) rats showed elevation of SR protein levels in retinal homogenates, attributed to the inner nuclear layer (INL) by immunofluorescence. Aqueous humor fluid from STZ-injected rats contained significantly higher levels of glutamate and D-serine compared to controls; by contrast, D-serine levels in retinas did not differ. Levels of activated JNK were elevated in diabetic retinas compared to controls. Conclusions Increased expression of SR in retina and higher levels of glutamate and D-serine in aqueous humor of STZ-treated rats may result from activation of the JNK pathway in diabetic sequelae. Our data suggest that the inflammatory conditions that prevail during DR result in elevation of D-serine, a neurotransmitter contributing to glutamate toxicity, potentially exacerbating the death of retinal ganglion cells in this condition.
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Affiliation(s)
- Haiyan Jiang
- School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical College, 270 Xueyuan Road, Wenzhou, Zhejiang 325003, P.R. China
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7
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Conti P, Tamborini L, Pinto A, Blondel A, Minoprio P, Mozzarelli A, De Micheli C. Drug Discovery Targeting Amino Acid Racemases. Chem Rev 2011; 111:6919-46. [DOI: 10.1021/cr2000702] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Paola Conti
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
| | - Lucia Tamborini
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
| | - Andrea Pinto
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
| | - Arnaud Blondel
- Institut Pasteur, Unité de Bioinformatique Structurale, CNRS-URA 2185, Département de Biologie Structurale et Chimie, 25 rue du Dr. Roux, 75724 Paris, France
| | - Paola Minoprio
- Institut Pasteur, Laboratoire des Processus Infectieux à Trypanosoma; Département d’Infection et Epidémiologie; 25 rue du Dr. Roux, 75724 Paris, France
| | - Andrea Mozzarelli
- Dipartimento di Biochimica e Biologia Molecolare, via G. P. Usberti 23/A, 43100 Parma, Italy
- Istituto di Biostrutture e Biosistemi, viale Medaglie d’oro, Roma, Italy
| | - Carlo De Micheli
- Dipartimento di Scienze Farmaceutiche “P. Pratesi”, via Mangiagalli 25, 20133 Milano, Italy
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Keularts IMLW, Leroy PLJM, Rubio-Gozalbo EM, Spaapen LJM, Weber B, Dorland B, de Koning TJ, Verhoeven-Duif NM. Fatal cerebral edema associated with serine deficiency in CSF. J Inherit Metab Dis 2010; 33 Suppl 3:S181-5. [PMID: 20300853 PMCID: PMC3757259 DOI: 10.1007/s10545-010-9067-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 02/04/2010] [Accepted: 02/09/2010] [Indexed: 11/17/2022]
Abstract
Two young girls without a notable medical history except for asthma presented with an acute toxic encephalopathy with very low serine concentrations both in plasma and cerebrospinal fluid (CSF) comparable to patients with 3-phosphoglycerate dehydrogenase (3-PGDH) deficiency. Clinical symptoms and enzyme measurement (in one patient) excluded 3-PGDH deficiency. Deficiencies in other serine biosynthesis enzymes were highly unlikely on clinical grounds. On basis of the fasting state, ketone bodies and lactate in plasma, urine and CSF, we speculate that reduced serine levels were due to its use as gluconeogenic substrate, conversion to pyruvate by brain serine racemase or decreased L-serine production because of a lack of glucose. These are the first strikingly similar cases of patients with a clear secondary serine deficiency associated with a toxic encephalopathy.
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Affiliation(s)
- Irene M L W Keularts
- Laboratory for Biochemical Genetics, Dept Clinical Genetics, Maastricht University Medical Center, P Debyelaan 25, 6229 HX Maastricht, The Netherlands.
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9
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d-Serine modulates neurogenic relaxation in rat corpus cavernosum. Biochem Pharmacol 2010; 79:1791-6. [DOI: 10.1016/j.bcp.2010.02.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 02/06/2010] [Accepted: 02/10/2010] [Indexed: 11/23/2022]
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Oliet SHR, Mothet JP. Regulation of N-methyl-D-aspartate receptors by astrocytic D-serine. Neuroscience 2008; 158:275-83. [PMID: 18358625 DOI: 10.1016/j.neuroscience.2008.01.071] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2007] [Revised: 01/28/2008] [Accepted: 01/28/2008] [Indexed: 10/22/2022]
Abstract
NMDA receptors (NMDARs) are key glutamatergic receptors in the CNS. Their permeability to Ca2+ and their voltage-dependent Mg2+ block make them essential for synaptic transmission, synaptic plasticity, rhythmogenesis, gene expression and excitotoxicity. One very peculiar property is that their activation requires the binding of both glutamate and a co-agonist like glycine or D-serine. There is a growing body of evidence indicating that D-serine, rather than glycine as originally thought, is the endogenous ligand for NMDARs in many brain structures. D-serine is synthesized mainly in glial cells and it is released upon activation of glutamate receptors. Its concentration in the synaptic cleft controls the number of NMDAR available for activation by glutamate. Consequently, the glial environment of neurons has a critical impact on the direction and magnitude of NMDAR-dependent synaptic plasticity.
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Affiliation(s)
- S H R Oliet
- Neurocentre Magendie, INSERM U862, 146 rue Léo Saignat, 33077 Bordeaux, France.
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11
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Williams SM, Diaz CM, Macnab LT, Sullivan RKP, Pow DV. Immunocytochemical analysis of D-serine distribution in the mammalian brain reveals novel anatomical compartmentalizations in glia and neurons. Glia 2006; 53:401-11. [PMID: 16342169 DOI: 10.1002/glia.20300] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
D-Serine is a co-agonist at the NMDA receptor glycine-binding site. Early studies have emphasized a glial localization for D-serine. However the nature of the glial cells has not been fully resolved, because previous D-serine antibodies needed glutaraldehyde-fixation, precluding co-localization with fixation-sensitive antigens. We have raised a new D-serine antibody optimized for formaldehyde-fixation. Light and electron microscopic observations indicated that D-serine was concentrated into vesicle-like compartments in astrocytes and radial glial cells, rather than being distributed uniformly in the cytoplasm. In aged animals, patches of cortex and hippocampus were devoid of immunolabeling for D-serine, suggesting that impaired glial modulation of forebrain glutamatergic signaling might occur. Dual immunofluorescence labeling for glutamate and D-serine revealed D-serine in a subset of glutamatergic neurons, particularly in brainstem regions and in the olfactory bulbs. Microglia also contain D-serine. We suggest that some D-serine may be derived from the periphery. Collectively, our data suggest that the cellular compartmentation and distribution of D-serine may be more complex and extensive than previously thought and may have significant implications for our understanding of the role of D-serine in disease states including hypoxia and schizophrenia.
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Affiliation(s)
- Susan M Williams
- Department of Anatomy, School of Biomedical Sciences, University of Newcastle, Callaghan, New South Wales 2308, Australia
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12
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Oliet SHR, Mothet JP. Molecular determinants ofD-serine-mediated gliotransmission: From release to function. Glia 2006; 54:726-737. [PMID: 17006901 DOI: 10.1002/glia.20356] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Since the late 80s, it is recognized that functional activation of N-methyl D-aspartate receptors (NMDARs) requires the binding of both glutamate and glycine. However, the surprising discovery that the wrong isomer of serine, D-serine, is present in mammals has profoundly challenged this dogmatic model of NMDARs activation. Indeed, there are accumulating evidence indicating that D-serine is the endogenous ligand for the glycine modulatory binding site in many brain areas. D-Serine is synthesized in glial cells by serine racemase (SR) and released upon activation of glutamate receptors. Here, we will provide an overview of recent findings on the molecular and cellular mechanisms involved in the synthesis and release of this gliotransmitter. We will also emphasize the function of this novel messenger in regulating synaptic excitatory transmission and plasticity in different brain areas. Because it fulfils all criteria for a gliotransmitter, D-serine regulatory action on glutamatergic transmission further illustrates the emerging concept of the "tripartite synapse".
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Affiliation(s)
- Stéphane H R Oliet
- INSERM U378 and Université Victor Segalen Bordeaux 2, 146 rue Léo Saignat, 33077 Bordeaux, France
| | - Jean-Pierre Mothet
- INSERM U378 and Université Victor Segalen Bordeaux 2, 146 rue Léo Saignat, 33077 Bordeaux, France
- Institut de Neurobiologie Alfred Fessard, Laboratoire de Neurobiologie Cellulaire et Moléculaire, CNRS UPR9040, 1 avenue de la Terrasse, 91198 Gif-sur-Yvette, France
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Wu SZ, Jiang S, Sims TJ, Barger SW. Schwann cells exhibit excitotoxicity consistent with release of NMDA receptor agonists. J Neurosci Res 2005; 79:638-43. [PMID: 15672444 DOI: 10.1002/jnr.20401] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Neurodegenerative effects of Schwann cells transplanted into the central nervous system have been observed previously. We report here that conditioned medium from Schwann cell cultures exhibit degenerative influences on hippocampal neurons. Aliquots of Schwann cell-conditioned medium compromised the morphologic integrity of the neurons, markedly elevated their intracellular calcium concentrations, and decreased their viability. The degenerative effects of Schwann cell medium on neuronal morphology and viability were blocked by N-methyl-D-aspartate (NMDA) receptor antagonists D-(-)-2-amino-5-phosphonopentanoic acid (D-APV) and 5,7-dicholorokynurenic acid (DCKA). Glutamate was detected in Schwann cell-conditioned medium at a concentration on the order of 10(-5) M. D-Amino acid oxidase (DAAOx) also attenuated the neurotoxicity exhibited by Schwann cells. These data suggest that Schwann cells release biologically relevant concentrations of excitotoxins that include glutamate and D-serine.
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Affiliation(s)
- Sheng-Zhou Wu
- Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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