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Yap SH, Lee CS, Zulkifli ND, Suresh D, Hamase K, Das KT, Rajasuriar R, Leong KH. D-Amino acids differentially trigger an inflammatory environment in vitro. Amino Acids 2024; 56:6. [PMID: 38310167 PMCID: PMC10838247 DOI: 10.1007/s00726-023-03360-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 12/20/2023] [Indexed: 02/05/2024]
Abstract
Studies in vivo have demonstrated that the accumulation of D-amino acids (D-AAs) is associated with age-related diseases and increased immune activation. However, the underlying mechanism(s) of these observations are not well defined. The metabolism of D-AAs by D-amino oxidase (DAO) produces hydrogen peroxide (H2O2), a reactive oxygen species involved in several physiological processes including immune response, cell differentiation, and proliferation. Excessive levels of H2O2 contribute to oxidative stress and eventual cell death, a characteristic of age-related pathology. Here, we explored the molecular mechanisms of D-serine (D-Ser) and D-alanine (D-Ala) in human liver cancer cells, HepG2, with a focus on the production of H2O2 the downstream secretion of pro-inflammatory cytokine and chemokine, and subsequent cell death. In HepG2 cells, we demonstrated that D-Ser decreased H2O2 production and induced concentration-dependent depolarization of mitochondrial membrane potential (MMP). This was associated with the upregulation of activated NF-кB, pro-inflammatory cytokine, TNF-α, and chemokine, IL-8 secretion, and subsequent apoptosis. Conversely, D-Ala-treated cells induced H2O2 production, and were also accompanied by the upregulation of activated NF-кB, TNF-α, and IL-8, but did not cause significant apoptosis. The present study confirms the role of both D-Ser and D-Ala in inducing inflammatory responses, but each via unique activation pathways. This response was associated with apoptotic cell death only with D-Ser. Further research is required to gain a better understanding of the mechanisms underlying D-AA-induced inflammation and its downstream consequences, especially in the context of aging given the wide detection of these entities in systemic circulation.
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Affiliation(s)
- Siew Hwei Yap
- Centre of Excellence for Research in AIDS (CERiA), Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Cheng Siang Lee
- Centre of Excellence for Research in AIDS (CERiA), Universiti Malaya, Kuala Lumpur, Malaysia
| | - Nur Diyana Zulkifli
- Department of Biomedical Sciences, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, Malaysia
| | - Darshinie Suresh
- Department of Biomedical Sciences, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, Malaysia
- Department of Biological Sciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, Malaysia
| | - Kenji Hamase
- Graduate School of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kumitaa Theva Das
- Department of Biomedical Sciences, Advanced Medical and Dental Institute, Universiti Sains Malaysia, Kepala Batas, Malaysia
| | - Reena Rajasuriar
- Centre of Excellence for Research in AIDS (CERiA), Universiti Malaya, Kuala Lumpur, Malaysia
- Department of Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
- Peter Doherty Institute for Infection and Immunity, Melbourne University, Melbourne, VIC, Australia
| | - Kok Hoong Leong
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Universiti Malaya, Kuala Lumpur, Malaysia.
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2
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Rabattoni V, Motta Z, Miceli M, Molla G, Fissore A, Adinolfi S, Pollegioni L, Sacchi S. On the regulation of human D-aspartate oxidase. Protein Sci 2023; 32:e4802. [PMID: 37805834 PMCID: PMC10588558 DOI: 10.1002/pro.4802] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 09/14/2023] [Accepted: 10/03/2023] [Indexed: 10/09/2023]
Abstract
The human flavoenzyme D-aspartate oxidase (hDASPO) controls the level of D-aspartate in the brain, a molecule acting as an agonist of NMDA receptors and modulator of AMPA and mGlu5 receptors. hDASPO-induced D-aspartate degradation prevents age-dependent deterioration of brain functions and is related to psychiatric disorders such as schizophrenia and autism. Notwithstanding this crucial role, less is known about hDASPO regulation. Here, we report that hDASPO is nitrosylated in vitro, while no evidence of sulfhydration and phosphorylation is apparent: nitrosylation affects the activity of the human flavoenzyme to a limited extent. Furthermore, hDASPO interacts with the primate-specific protein pLG72 (a well-known negative chaperone of D-amino acid oxidase, the enzyme deputed to D-serine degradation in the human brain), yielding a ~114 kDa complex, with a micromolar dissociation constant, promoting the flavoenzyme inactivation. At the cellular level, pLG72 and hDASPO generate a cytosolic complex: the expression of pLG72 negatively affects the hDASPO level by reducing its half-life. We propose that pLG72 binding may represent a protective mechanism aimed at avoiding cytotoxicity due to H2 O2 produced by the hDASPO enzymatic degradation of D-aspartate, especially before the final targeting to peroxisomes.
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Affiliation(s)
- Valentina Rabattoni
- “The Protein Factory 2.0”, Dipartimento di Biotecnologie e Scienze della VitaUniversità degli studi dell'InsubriaVareseItaly
| | - Zoraide Motta
- “The Protein Factory 2.0”, Dipartimento di Biotecnologie e Scienze della VitaUniversità degli studi dell'InsubriaVareseItaly
| | - Matteo Miceli
- “The Protein Factory 2.0”, Dipartimento di Biotecnologie e Scienze della VitaUniversità degli studi dell'InsubriaVareseItaly
| | - Gianluca Molla
- “The Protein Factory 2.0”, Dipartimento di Biotecnologie e Scienze della VitaUniversità degli studi dell'InsubriaVareseItaly
| | - Alex Fissore
- Dipartimento di Scienza e Tecnologia del FarmacoUniversità di TorinoTorinoItaly
| | - Salvatore Adinolfi
- Dipartimento di Scienza e Tecnologia del FarmacoUniversità di TorinoTorinoItaly
| | - Loredano Pollegioni
- “The Protein Factory 2.0”, Dipartimento di Biotecnologie e Scienze della VitaUniversità degli studi dell'InsubriaVareseItaly
| | - Silvia Sacchi
- “The Protein Factory 2.0”, Dipartimento di Biotecnologie e Scienze della VitaUniversità degli studi dell'InsubriaVareseItaly
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3
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Chen CT, Shao Z, Fu Z. Dysfunctional peroxisomal lipid metabolisms and their ocular manifestations. Front Cell Dev Biol 2022; 10:982564. [PMID: 36187472 PMCID: PMC9524157 DOI: 10.3389/fcell.2022.982564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 08/17/2022] [Indexed: 11/13/2022] Open
Abstract
Retina is rich in lipids and dyslipidemia causes retinal dysfunction and eye diseases. In retina, lipids are not only important membrane component in cells and organelles but also fuel substrates for energy production. However, our current knowledge of lipid processing in the retina are very limited. Peroxisomes play a critical role in lipid homeostasis and genetic disorders with peroxisomal dysfunction have different types of ocular complications. In this review, we focus on the role of peroxisomes in lipid metabolism, including degradation and detoxification of very-long-chain fatty acids, branched-chain fatty acids, dicarboxylic acids, reactive oxygen/nitrogen species, glyoxylate, and amino acids, as well as biosynthesis of docosahexaenoic acid, plasmalogen and bile acids. We also discuss the potential contributions of peroxisomal pathways to eye health and summarize the reported cases of ocular symptoms in patients with peroxisomal disorders, corresponding to each disrupted peroxisomal pathway. We also review the cross-talk between peroxisomes and other organelles such as lysosomes, endoplasmic reticulum and mitochondria.
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Affiliation(s)
- Chuck T Chen
- Department of Nutritional Sciences, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Zhuo Shao
- Post-Graduate Medical Education, University of Toronto, Toronto, ON, Canada
- Division of Clinical and Metabolic Genetics, the Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
- The Genetics Program, North York General Hospital, University of Toronto, Toronto, ON, Canada
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA, United States
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4
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Plasma d-amino acids are associated with markers of immune activation and organ dysfunction in people with HIV. AIDS 2022; 36:911-921. [PMID: 35212669 DOI: 10.1097/qad.0000000000003207] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND d-Amino acids (d-AAs) have been associated with age-associated conditions in the general population but their relevance in people with HIV (PWH), who experience accentuated/accelerated aging has not been studied. We compared d-AA levels in HIV-infected and uninfected controls and explored their association with markers of immune activation, gut permeability and organ dysfunction. DESIGN Case-control analysis. METHOD Plasma samples from 60 antiretroviral therapy-treated HIV-infected individuals and 59 uninfected controls were analysed. A three-dimensional HPLC system was used to measure d-and l-asparagine, serine, alanine and proline and presented as %d-AA. Additionally, cell-associated and soluble markers of immune activation and senescence were characterized. Kidney and liver functions were expressed as estimated glomerular filtration rate and fibrosis-4 scores, respectively. Mann-Whitney and Spearman rank correlation coefficients were used for statistical analysis. RESULTS d-Asparagine, d-serine, d-alanine and d-proline were detectable in all plasma samples and correlated with age in HIV-infected and uninfected but not different between groups. Kynurenine/tryptophan ratio was positively correlated with all %d-AAs in PWH and with %d-serine and %d-proline in controls. %d-AAs were not consistently correlated with markers of gut permeability in both groups. All %d-AAs were also correlated with kidney function in both groups whereas age-associated accumulation of %d-asparagine, %d-serine and %d-proline were correlated with liver function and the VACS score in controls. CONCLUSION Plasma d-AAs are associated with chronological age and correlated with markers of immune activation and organ decline, though variably, in PWH and controls. Their role in the biology of aging warrants further investigation.
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Moussa S, Rosini E, Chitsaz D, Pollegioni L, Kennedy TE, Mauzeroll J. High-Throughput Strategy for Glycine Oxidase Biosensor Development Reveals Glycine Release from Cultured Cells. Anal Chem 2021; 93:16504-16511. [PMID: 34843206 DOI: 10.1021/acs.analchem.1c03620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Glycine is an important biomarker in clinical analysis due to its involvement in multiple physiological processes. As such, the need for low-cost analytical tools for glycine detection is growing. As a neurotransmitter, glycine is involved in inhibitory and excitatory neurochemical transmission in the central nervous system. In this work, we present a 10 μM Pt-based electrochemical enzymatic biosensor based on the flavoenzyme glycine oxidase (GO) for localized real-time measurements of glycine. Among GO variants at position 244, the H244K variant with increased glycine turnover was selected to develop a functional biosensor. This biosensor relies on amperometric readouts and does not require additional redox mediators. The biosensor was characterized and applied for glycine detection from cells, mainly HEK 293 cells and primary rat astrocytes. We have identified an enzyme, GO H244K, with increased glycine turnover using mutagenesis but which can be developed into a functional biosensor. Noteworthy, a glycine release of 395.7 ± 123 μM from primary astrocytes was measured, which is ∼fivefold higher than glycine release from HEK 293 cells (75.4 ± 3.91 μM) using the GO H244K biosensor.
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Affiliation(s)
- Siba Moussa
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
| | - Elena Rosini
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi deII'Insubria, via J. H. Dunant 3, Varese 21100, Italy
| | - Daryan Chitsaz
- Integrated Program in Neuroscience, McGill University, 1033 Pine Ave. W., Montreal, Quebec H3A 1A1, Canada
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi deII'Insubria, via J. H. Dunant 3, Varese 21100, Italy
| | - Timothy E Kennedy
- McGill Program in Neuroengineering, Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Janine Mauzeroll
- Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec H3A 0B8, Canada
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6
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Pollegioni L, Molla G, Sacchi S, Murtas G. Human D-aspartate Oxidase: A Key Player in D-aspartate Metabolism. Front Mol Biosci 2021; 8:689719. [PMID: 34250021 PMCID: PMC8260693 DOI: 10.3389/fmolb.2021.689719] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/09/2021] [Indexed: 11/15/2022] Open
Abstract
In recent years, the D-enantiomers of amino acids have been recognized as natural molecules present in all kingdoms, playing a variety of biological roles. In humans, d-serine and d-aspartate attracted attention for their presence in the central nervous system. Here, we focus on d-aspartate, which is involved in glutamatergic neurotransmission and the synthesis of various hormones. The biosynthesis of d-aspartate is still obscure, while its degradation is due to the peroxisomal flavin adenine dinucleotide (FAD)-containing enzyme d-aspartate oxidase. d-Aspartate emergence is strictly controlled: levels decrease in brain within the first days of life while increasing in endocrine glands postnatally and through adulthood. The human d-aspartate oxidase (hDASPO) belongs to the d-amino acid oxidase-like family: its tertiary structure closely resembles that of human d-amino acid oxidase (hDAAO), the enzyme that degrades neutral and basic d-amino acids. The structure-function relationships of the physiological isoform of hDASPO (named hDASPO_341) and the regulation of gene expression and distribution and properties of the longer isoform hDASPO_369 have all been recently elucidated. Beyond the substrate preference, hDASPO and hDAAO also differ in kinetic efficiency, FAD-binding affinity, pH profile, and oligomeric state. Such differences suggest that evolution diverged to create two different ways to modulate d-aspartate and d-serine levels in the human brain. Current knowledge about hDASPO is shedding light on the molecular mechanisms underlying the modulation of d-aspartate levels in human tissues and is pushing novel, targeted therapeutic strategies. Now, it has been proposed that dysfunction in NMDA receptor-mediated neurotransmission is caused by disrupted d-aspartate metabolism in the nervous system during the onset of various disorders (such as schizophrenia): the design of suitable hDASPO inhibitors aimed at increasing d-aspartate levels thus represents a novel and useful form of therapy.
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Affiliation(s)
- Loredano Pollegioni
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Gianluca Molla
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Silvia Sacchi
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
| | - Giulia Murtas
- Department of Biotechnology and Life Sciences, University of Insubria, Varese, Italy
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7
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Sacchi S, Rabattoni V, Miceli M, Pollegioni L. Yin and Yang in Post-Translational Modifications of Human D-Amino Acid Oxidase. Front Mol Biosci 2021; 8:684934. [PMID: 34041270 PMCID: PMC8141710 DOI: 10.3389/fmolb.2021.684934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Accepted: 04/23/2021] [Indexed: 11/30/2022] Open
Abstract
In the central nervous system, the flavoprotein D-amino acid oxidase is responsible for catabolizing D-serine, the main endogenous coagonist of N-methyl-D-aspartate receptor. Dysregulation of D-serine brain levels in humans has been associated with neurodegenerative and psychiatric disorders. This D-amino acid is synthesized by the enzyme serine racemase, starting from the corresponding L-enantiomer, and degraded by both serine racemase (via an elimination reaction) and the flavoenzyme D-amino acid oxidase. To shed light on the role of human D-amino acid oxidase (hDAAO) in D-serine metabolism, the structural/functional relationships of this enzyme have been investigated in depth and several strategies aimed at controlling the enzymatic activity have been identified. Here, we focused on the effect of post-translational modifications: by using a combination of structural analyses, biochemical methods, and cellular studies, we investigated whether hDAAO is subjected to nitrosylation, sulfhydration, and phosphorylation. hDAAO is S-nitrosylated and this negatively affects its activity. In contrast, the hydrogen sulfide donor NaHS seems to alter the enzyme conformation, stabilizing a species with higher affinity for the flavin adenine dinucleotide cofactor and thus positively affecting enzymatic activity. Moreover, hDAAO is phosphorylated in cerebellum; however, the protein kinase involved is still unknown. Taken together, these findings indicate that D-serine levels can be also modulated by post-translational modifications of hDAAO as also known for the D-serine synthetic enzyme serine racemase.
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Affiliation(s)
- Silvia Sacchi
- "The Protein Factory 2.0", Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi Dell'Insubria, Varese, Italy
| | - Valentina Rabattoni
- "The Protein Factory 2.0", Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi Dell'Insubria, Varese, Italy
| | - Matteo Miceli
- "The Protein Factory 2.0", Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi Dell'Insubria, Varese, Italy
| | - Loredano Pollegioni
- "The Protein Factory 2.0", Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi Dell'Insubria, Varese, Italy
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8
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Tseng YS, Liao CH, Wu WB, Ma MC. N-methyl-d-aspartate receptor hyperfunction contributes to d-serine-mediated renal insufficiency. Am J Physiol Renal Physiol 2021; 320:F799-F813. [PMID: 33749324 DOI: 10.1152/ajprenal.00461.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 03/18/2021] [Indexed: 01/07/2023] Open
Abstract
Glutamate N-methyl-d-aspartate receptor (NMDAR) hyperfunction is known to contribute to acute renal failure due to ischemia-reperfusion and endotoxemia. d-Serine is a coagonist for NMDAR activation, but whether NMDARs play a role in d-serine-mediated nephrotoxicity remains unclear. Here, we demonstrate that NMDAR blockade ameliorated d-serine-induced renal injury. In NMDAR-expressing LLC-PK1 cells, which were used as a proximal tubule model, d-serine but not l-serine induced cytotoxicity in a dose-dependent manner, which was abrogated by the selective NMDAR blockers MK-801 and AP-5. Time-dependent oxidative stress, evidenced by gradually increased superoxide and H2O2 production, was associated with d-serine-mediated cytotoxicity; these reactive oxygen species could be alleviated not only after NMDAR inhibition but also by NADPH oxidase (NOX) inhibition. Activation of protein kinase C (PKC)-δ and PKC-ζ is a downstream signal for NMDAR-mediated NOX activation because PKC inhibition diminishes the NOX activity that is induced by d-serine. Renal injury was further confirmed in male Wistar rats that intraperitoneally received d-serine but not l-serine. Peak changes in glucosuria, proteinuria, and urinary excretion of lactate dehydrogenase and malondialdehyde were found after 24 h of treatment. Persistent tubular damage was observed after 7 days of treatment. Cotreatment with the NMDAR blocker MK-801 for 24 h abolished d-serine-induced functional insufficiency and tubular damage. MK-801 attenuated renal superoxide formation by lowering NOX activity and protein upregulation of NOX4 but not NOX2. These results reveal that NMDAR hyperfunction underlies d-serine-induced renal injury via the effects of NOX4 on triggering oxidative stress.NEW & NOTEWORTHY Ionotropic N-methyl-d-aspartate receptors (NMDARs) are not only present in the nervous system but also expressed in the kidney. Overstimulation of renal NMDARs leads to oxidative stress via the signal pathway of calcium/protein kinase C/NADPH oxidase in d-serine-mediated tubular cell damage. Intervention of NMDAR blockade may prevent acute renal injury caused by d-serine.
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Affiliation(s)
- Yi-Shiou Tseng
- Division of Urology, Department of Surgery, Far Eastern Memorial Hospital, New Taipei, Taiwan
| | - Chun-Hou Liao
- Divisions of Urology, Department of Surgery, Cardinal Tien Hospital, New Taipei, Taiwan
- School of Medicine, Fu Jen Catholic University, New Taipei, Taiwan
| | - Wen-Bin Wu
- School of Medicine, Fu Jen Catholic University, New Taipei, Taiwan
| | - Ming-Chieh Ma
- School of Medicine, Fu Jen Catholic University, New Taipei, Taiwan
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9
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Kashyap S, Shivakumar N, Sejian V, Deutz NEP, Preston T, Sreeman S, Devi S, Kurpad AV. Goat milk protein digestibility in relation to intestinal function. Am J Clin Nutr 2021; 113:845-853. [PMID: 33677496 PMCID: PMC8023838 DOI: 10.1093/ajcn/nqaa400] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 11/27/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Milk is an important high-quality animal protein source in low- and middle-income countries (LMICs). Although the true ileal digestibility and absorption of milk has been shown to be high in French adults, this may be lower in individuals from LMICs who are at risk of environmental enteropathy. OBJECTIVE To determine the true ileal indispensable amino acid (IAA) digestibility of intrinsically labeled goat milk protein in South Indian women of reproductive age (WRA), using the dual-isotope tracer technique, and to measure intestinal absorption of amino acid and inert sugar in the same participants using L-allo-isoleucine and a dual-sugar assay. METHODS Milk with 2H-labeled protein collected from a lactating goat fed intrinsically 2H-labeled fodder (maize and cowpea) was spray dried. Labeled milk protein was administered in a plateau feeding protocol to WRA with normal BMI, in whom urinary lactulose and mannitol recovery and the lactulose/mannitol ratio (LMR) were measured, to determine its true ileal IAA digestibility by the dual-isotope tracer technique with a reference U-13C-amino acid mixture. A phenylalanine absorption index was calculated from the plasma to meal ratio of 13C9 phenylalanine within the digestibility protocol. On a separate day, the allo-isoleucine absorption index was estimated from the ratio of plasma allo-isoleucine enrichments after oral 13C6-15N-L- and intravenous 2H10-L-allo-isoleucine administration. RESULTS The means ± SDs of true ileal IAA digestibility of goat milk protein, lactulose and mannitol recovery, LMR, allo-isoleucine and phenylalanine absorption index were 94.0 ± 2.9%, 0.09 ± 0.03%, 7.9 ± 2.3%, 0.012 ± 0.004, 88.4 ± 3.8% and 24.5 ± 1.6%, respectively. The LMR correlated with the allo-isoleucine absorption index (rs = -0.93, P = 0.008). CONCLUSION The true ileal digestibility of goat milk protein in South Indian WRA with normal intestinal absorptive function and integrity was comparable to earlier estimates in healthy French adults.
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Affiliation(s)
- Sindhu Kashyap
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Nirupama Shivakumar
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Veerasamy Sejian
- ICAR—National Institute of Animal Nutrition and Physiology, Adugodi, Bangalore, India
| | - Nicolaas E P Deutz
- Center for Translational Research in Aging and Longevity, Department of Health and Kinesiology, Texas A&M University, College Station, TX, USA
| | - Thomas Preston
- Scottish Universities Environmental Research Centre, East Kilbride, Scotland, UK
| | - Sheshshayee Sreeman
- Department of Crop Physiology, University of Agricultural Sciences, Bangalore, India
| | - Sarita Devi
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
| | - Anura V Kurpad
- Division of Nutrition, St. John's Research Institute, St. John's National Academy of Health Sciences, Bangalore, India
- Department of Physiology, St. John's Medical College, St. John's National Academy of Health Sciences, Bangalore, India
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10
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Pei JC, Luo DZ, Gau SS, Chang CY, Lai WS. Directly and Indirectly Targeting the Glycine Modulatory Site to Modulate NMDA Receptor Function to Address Unmet Medical Needs of Patients With Schizophrenia. Front Psychiatry 2021; 12:742058. [PMID: 34658976 PMCID: PMC8517243 DOI: 10.3389/fpsyt.2021.742058] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 09/02/2021] [Indexed: 12/30/2022] Open
Abstract
Schizophrenia is a severe mental illness that affects ~1% of the world's population. It is clinically characterized by positive, negative, and cognitive symptoms. Currently available antipsychotic medications are relatively ineffective in improving negative and cognitive deficits, which are related to a patient's functional outcomes and quality of life. Negative symptoms and cognitive deficits are unmet by the antipsychotic medications developed to date. In recent decades, compelling animal and clinical studies have supported the NMDA receptor (NMDAR) hypofunction hypothesis of schizophrenia and have suggested some promising therapeutic agents. Notably, several NMDAR-enhancing agents, especially those that function through the glycine modulatory site (GMS) of NMDAR, cause significant reduction in psychotic and cognitive symptoms in patients with schizophrenia. Given that the NMDAR-mediated signaling pathway has been implicated in cognitive/social functions and that GMS is a potential therapeutic target for enhancing the activation of NMDARs, there is great interest in investigating the effects of direct and indirect GMS modulators and their therapeutic potential. In this review, we focus on describing preclinical and clinical studies of direct and indirect GMS modulators in the treatment of schizophrenia, including glycine, D-cycloserine, D-serine, glycine transporter 1 (GlyT1) inhibitors, and D-amino acid oxidase (DAO or DAAO) inhibitors. We highlight some of the most promising recently developed pharmacological compounds designed to either directly or indirectly target GMS and thus augment NMDAR function to treat the cognitive and negative symptoms of schizophrenia. Overall, the current findings suggest that indirectly targeting of GMS appears to be more beneficial and leads to less adverse effects than direct targeting of GMS to modulate NMDAR functions. Indirect GMS modulators, especially GlyT1 inhibitors and DAO inhibitors, open new avenues for the treatment of unmet medical needs for patients with schizophrenia.
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Affiliation(s)
- Ju-Chun Pei
- Department of Psychology, National Taiwan University, Taipei, Taiwan
| | - Da-Zhong Luo
- Department of Psychology, National Taiwan University, Taipei, Taiwan
| | - Shiang-Shin Gau
- Department of Psychology, National Taiwan University, Taipei, Taiwan
| | - Chia-Yuan Chang
- Department of Psychology, National Taiwan University, Taipei, Taiwan.,Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan
| | - Wen-Sung Lai
- Department of Psychology, National Taiwan University, Taipei, Taiwan.,Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, Taiwan.,Graduate Institute of Brain and Mind Sciences, National Taiwan University, Taipei, Taiwan
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11
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Orzylowski M, Fujiwara E, Mousseau DD, Baker GB. An Overview of the Involvement of D-Serine in Cognitive Impairment in Normal Aging and Dementia. Front Psychiatry 2021; 12:754032. [PMID: 34707525 PMCID: PMC8542907 DOI: 10.3389/fpsyt.2021.754032] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 09/02/2021] [Indexed: 12/14/2022] Open
Abstract
Dementia, of which Alzheimer's disease (AD) is the most common form, is characterized by progressive cognitive deterioration, including profound memory loss, which affects functioning in many aspects of life. Although cognitive deterioration is relatively common in aging and aging is a risk factor for AD, the condition is not necessarily a part of the aging process. The N-methyl-D-aspartate glutamate receptor (NMDAR) and its co-agonist D-serine are currently of great interest as potential important contributors to cognitive function in normal aging and dementia. D-Serine is necessary for activation of the NMDAR and in maintenance of long-term potentiation (LTP) and is involved in brain development, neuronal connectivity, synaptic plasticity and regulation of learning and memory. In this paper, we review evidence, from both preclinical and human studies, on the involvement of D-serine (and the enzymes involved in its metabolism) in regulation of cognition. Potential mechanisms of action of D-serine are discussed in the context of normal aging and in dementia, as is the potential for using D-serine as a potential biomarker and/or therapeutic agent in dementia. Although there is some controversy in the literature, it has been proposed that in normal aging there is decreased expression of serine racemase and decreased levels of D-serine and down-regulation of NMDARs, resulting in impaired synaptic plasticity and deficits in learning and memory. In contrast, in AD there appears to be activation of serine racemase, increased levels of D-serine and overstimulation of NMDARs, resulting in cytotoxicity, synaptic deficits, and dementia.
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Affiliation(s)
- Magdalena Orzylowski
- Villa Caritas Geriatric Psychiatry Hospital, Edmonton, AB, Canada.,Department of Psychiatry, University of Alberta, Edmonton, AB, Canada
| | - Esther Fujiwara
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
| | - Darrell D Mousseau
- Department of Psychiatry, University of Saskatchewan, Saskatoon, SK, Canada
| | - Glen B Baker
- Department of Psychiatry, University of Alberta, Edmonton, AB, Canada.,Neuroscience and Mental Health Institute, University of Alberta, Edmonton, AB, Canada
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12
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Murtas G, Marcone GL, Sacchi S, Pollegioni L. L-serine synthesis via the phosphorylated pathway in humans. Cell Mol Life Sci 2020; 77:5131-5148. [PMID: 32594192 PMCID: PMC11105101 DOI: 10.1007/s00018-020-03574-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 06/03/2020] [Accepted: 06/12/2020] [Indexed: 12/12/2022]
Abstract
L-serine is a nonessential amino acid in eukaryotic cells, used for protein synthesis and in producing phosphoglycerides, glycerides, sphingolipids, phosphatidylserine, and methylenetetrahydrofolate. Moreover, L-serine is the precursor of two relevant coagonists of NMDA receptors: glycine (through the enzyme serine hydroxymethyltransferase), which preferentially acts on extrasynaptic receptors and D-serine (through the enzyme serine racemase), dominant at synaptic receptors. The cytosolic "phosphorylated pathway" regulates de novo biosynthesis of L-serine, employing 3-phosphoglycerate generated by glycolysis and the enzymes 3-phosphoglycerate dehydrogenase, phosphoserine aminotransferase, and phosphoserine phosphatase (the latter representing the irreversible step). In the human brain, L-serine is primarily found in glial cells and is supplied to neurons for D-serine synthesis. Serine-deficient patients show severe neurological symptoms, including congenital microcephaly, psychomotor retardation, and intractable seizures, thus highlighting the relevance of de novo production of this amino acid in brain development and morphogenesis. Indeed, the phosphorylated pathway is strictly linked to cancer. Moreover, L-serine has been suggested as a ready-to-use treatment, as also recently proposed for Alzheimer's disease. Here, we present our current state of knowledge concerning the three mammalian enzymes of the phosphorylated pathway and known mutations related to pathological conditions: although the structure of these enzymes has been solved, how enzyme activity is regulated remains largely unknown. We believe that an in-depth investigation of these enzymes is crucial to identify the molecular mechanisms involved in modulating concentrations of the serine enantiomers and for studying the interplay between glial and neuronal cells and also to determine the most suitable therapeutic approach for various diseases.
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Affiliation(s)
- Giulia Murtas
- Department of Biotechnology and Life Sciences, University of Insubria, Via J. H. Dunant 3, 21100, Varese, Italy
| | - Giorgia Letizia Marcone
- Department of Biotechnology and Life Sciences, University of Insubria, Via J. H. Dunant 3, 21100, Varese, Italy
| | - Silvia Sacchi
- Department of Biotechnology and Life Sciences, University of Insubria, Via J. H. Dunant 3, 21100, Varese, Italy
| | - Loredano Pollegioni
- Department of Biotechnology and Life Sciences, University of Insubria, Via J. H. Dunant 3, 21100, Varese, Italy.
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13
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Mechanistic insights into the loss-of-function mechanisms of rare human D-amino acid oxidase variants implicated in amyotrophic lateral sclerosis. Sci Rep 2020; 10:17146. [PMID: 33051492 PMCID: PMC7555490 DOI: 10.1038/s41598-020-74048-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/25/2020] [Indexed: 12/13/2022] Open
Abstract
Impaired enzymatic activity in D-amino acid oxidase (DAAO) caused by missense mutations has been shown to trigger amyotrophic lateral sclerosis (ALS) through an abnormal accumulation of D-serine in the spinal cord. While loss of enzymatic functions of certain ALS-causing DAAO variants have been studied before, a detailed understanding of structure-dynamics-function relationship of the rare DAAO variants has not been investigated hitherto. To address this, we carried out a comprehensive study of all the reported rare DAAO variants. By employing a spectrum of bioinformatics analyses along with extensive structural dynamics simulations, we show that certain rare variants disrupted key interactions with the active site and decreased the conformational flexibility of active site loop comprising residues 216-228, which is essential for substrate binding and product release. Moreover, these variants lost crucial interactions with the cofactor flavin-adenine-dinucleotide, resulting in weaker binding affinity. A detailed inspection revealed that these variants exhibited such characteristics due to the abrogation of specific salt bridges. Taken together, our study provides a gateway into the structural-dynamic features of the rare DAAO variants and highlights the importance of informatics-based integrated analyses in the screening and prioritization of variants a priori to the clinical-functional characterization.
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14
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Seckler JM, Lewis SJ. Advances in D-Amino Acids in Neurological Research. Int J Mol Sci 2020; 21:ijms21197325. [PMID: 33023061 PMCID: PMC7582301 DOI: 10.3390/ijms21197325] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/29/2020] [Accepted: 09/29/2020] [Indexed: 12/16/2022] Open
Abstract
D-amino acids have been known to exist in the human brain for nearly 40 years, and they continue to be a field of active study to today. This review article aims to give a concise overview of the recent advances in D-amino acid research as they relate to the brain and neurological disorders. This work has largely been focused on modulation of the N-methyl-D-aspartate (NMDA) receptor and its relationship to Alzheimer’s disease and Schizophrenia, but there has been a wealth of novel research which has elucidated a novel role for several D-amino acids in altering brain chemistry in a neuroprotective manner. D-amino acids which have no currently known activity in the brain but which have active derivatives will also be reviewed.
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Affiliation(s)
- James M. Seckler
- Department Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106, USA
- Correspondence:
| | - Stephen J. Lewis
- Department Pediatrics, Case Western Reserve University, Cleveland, OH 44106, USA;
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15
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Dysfunctional d-aspartate metabolism in BTBR mouse model of idiopathic autism. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140531. [PMID: 32853769 DOI: 10.1016/j.bbapap.2020.140531] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Revised: 07/22/2020] [Accepted: 07/31/2020] [Indexed: 12/16/2022]
Abstract
BACKGROUND Autism spectrum disorders (ASD) comprise a heterogeneous group of neurodevelopmental conditions characterized by impairment in social interaction, deviance in communication, and repetitive behaviors. Dysfunctional ionotropic NMDA and AMPA receptors, and metabotropic glutamate receptor 5 activity at excitatory synapses has been recently linked to multiple forms of ASD. Despite emerging evidence showing that d-aspartate and d-serine are important neuromodulators of glutamatergic transmission, no systematic investigation on the occurrence of these D-amino acids in preclinical ASD models has been carried out. METHODS Through HPLC and qPCR analyses we investigated d-aspartate and d-serine metabolism in the brain and serum of four ASD mouse models. These include BTBR mice, an idiopathic model of ASD, and Cntnap2-/-, Shank3-/-, and 16p11.2+/- mice, three established genetic mouse lines recapitulating high confidence ASD-associated mutations. RESULTS Biochemical and gene expression mapping in Cntnap2-/-, Shank3-/-, and 16p11.2+/- failed to find gross cerebral and serum alterations in d-aspartate and d-serine metabolism. Conversely, we found a striking and stereoselective increased d-aspartate content in the prefrontal cortex, hippocampus and serum of inbred BTBR mice. Consistent with biochemical assessments, in the same brain areas we also found a robust reduction in mRNA levels of d-aspartate oxidase, encoding the enzyme responsible for d-aspartate catabolism. CONCLUSIONS Our results demonstrated the presence of disrupted d-aspartate metabolism in a widely used animal model of idiopathic ASD. GENERAL SIGNIFICANCE Overall, this work calls for a deeper investigation of D-amino acids in the etiopathology of ASD and related developmental disorders.
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Puggioni V, Savinelli A, Miceli M, Molla G, Pollegioni L, Sacchi S. Biochemical characterization of mouse d-aspartate oxidase. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140472. [PMID: 32553892 DOI: 10.1016/j.bbapap.2020.140472] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 05/27/2020] [Accepted: 06/10/2020] [Indexed: 12/15/2022]
Abstract
D-amino acids research field has recently gained an increased interest since these atypical molecules have been discovered to play a plethora of different roles. In the mammalian central nervous system, d-aspartate (D-Asp) is critically involved in the regulation of glutamatergic neurotransmission by acting as an agonist of NMDA receptor. Accordingly, alterations in its metabolism have been related to different pathologies. D-Asp shows a peculiar temporal pattern of emergence during ontogenesis and soon after birth its brain levels are strictly regulated by the catabolic enzyme d-aspartate oxidase (DASPO), a FAD-dependent oxidase. Rodents have been widely used as in vivo models for deciphering molecular mechanisms and for testing novel therapeutic targets and drugs, but human targets can significantly differ. Based on these considerations, here we investigated the structural and functional properties of the mouse DASPO, in particular kinetic properties, ligand and flavin binding, oligomerization state and protein stability. We compared the obtained findings with those of the human enzyme (80% sequence identity) highlighting a different oligomeric state and a lower activity for the mouse DASPO, which apoprotein species exists in solution in two forms differing in FAD affinity. The features that distinguish mouse and human DASPO suggest that this flavoenzyme might control in a distinct way the brain D-Asp levels in different organisms.
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Affiliation(s)
- Vincenzo Puggioni
- "The Protein Factory 2.0", Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| | - Antonio Savinelli
- "The Protein Factory 2.0", Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| | - Matteo Miceli
- "The Protein Factory 2.0", Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| | - Gianluca Molla
- "The Protein Factory 2.0", Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy
| | - Loredano Pollegioni
- "The Protein Factory 2.0", Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy; International Research Center on D-amino acids DAAIR, via Lepetit 34, 21040, Gerenzano (VA), Italy
| | - Silvia Sacchi
- "The Protein Factory 2.0", Dipartimento di Biotecnologie e Scienze della Vita, Università degli studi dell'Insubria, via J. H. Dunant 3, 21100 Varese, Italy; International Research Center on D-amino acids DAAIR, via Lepetit 34, 21040, Gerenzano (VA), Italy.
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17
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Development of a cognitive function marker based on D-amino acid proportions using new chiral tandem LC-MS/MS systems. Sci Rep 2020; 10:804. [PMID: 31965028 PMCID: PMC6972825 DOI: 10.1038/s41598-020-57878-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/27/2019] [Indexed: 12/14/2022] Open
Abstract
The incidence of dementia, a clinical symptom characterized by severe cognitive decline, is increasing worldwide. Predictive biomarkers are therefore required for early identification and management. D-amino acids in the brain contribute to cognitive function and are suggested as useful biomarkers for diagnosing dementia risk. To clarify their relationship with human cognitive decline, we developed an identification method of chiral metabolomics for detecting slight differences in chiral amino acid amounts. Chiral tandem liquid chromatography-tandem mass spectrometry systems were applied for sensitive and selective amino acid species along with chiral species determination based on anion and zwitterion exchange mechanisms. In a comprehensive health cohort (cross-sectional study), we measured blood chiral amino acid levels from 305 women (65–80 years old) classified into Control, Mild-cognitive-Impairment (MCI), and Dementia groups using the Mini-Mental State Examination. MCI exhibited higher D-Pro (D-Pro/(D-Pro + L-Pro)) proportion vs the Control group, suggesting this proportion as a useful biomarker for MCI. Biomarker accuracy was improved in combination with D-Ser proportion. Receiver operating characteristics analysis of the Control vs. MCI proportion obtained area under the curve (0.80) with 70% sensitivity and 84% specificity at the optimal cutoff value (0.30). Thus, dementia monitoring can be improved by including trace D-amino acids measurements.
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18
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Murtas G, Sacchi S, Pollegioni L. Substitution of Arginine 120 in Human D-Amino Acid Oxidase Favors FAD-Binding and Nuclear Mistargeting. Front Mol Biosci 2019; 6:125. [PMID: 31799256 PMCID: PMC6862323 DOI: 10.3389/fmolb.2019.00125] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 10/28/2019] [Indexed: 01/23/2023] Open
Abstract
The peroxisomal enzyme human D-amino acid oxidase (hDAAO) is attracting attention owing to its role in degrading D-serine, the main co-agonist of N-methyl D-aspartate receptors in brain, and its involvement in brain functions and diseases. Here, we focused on arginine 120, a residue located at the protein interface, 20 Å from the assumed second ligand-binding site, showing a different orientation of the side chain in the hDAAO-benzoate complex, and corresponding to Ser119 in rat DAAO, which is part of a putative nuclear translocation signal (NTS). By substituting Arg120 in hDAAO with a glutamate (to mimic the active NTS) or a leucine (to eliminate the positive charge) the protein conformation, thermal stability, and kinetic properties are slightly altered, while the dimeric structure and the ligand-binding properties are unchanged. The most relevant alteration in Arg120 variants is the strongest interaction with FAD. Nevertheless, the activity assayed at low D-serine and FAD concentrations (resembling physiological conditions) was quite similar for wild-type and Arg120 hDAAO variants. These results resemble the ones obtained substituting another residue located at the interface region (i.e., the W209R variant), indicating that substitutions at the monomer-monomer interface mainly affects the FAD binding in hDAAO. Indeed, U87 glioblastoma cells transiently transfected for hDAAO variants show that substitution of Arg120 favors mistargeting: the increase in cytosolic localization observed for the variants promotes nuclear targeting, especially for the R120E hDAAO, without affecting cell viability. Notably, mistargeting to the nucleus is an innate process as it is apparent for the wild-type hDAAO, too: whether such a process is related to specific pathologic processes is still unknown.
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Affiliation(s)
- Giulia Murtas
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
| | - Silvia Sacchi
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
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19
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Bastings JJ, van Eijk HM, Olde Damink SW, Rensen SS. d-amino Acids in Health and Disease: A Focus on Cancer. Nutrients 2019; 11:nu11092205. [PMID: 31547425 PMCID: PMC6770864 DOI: 10.3390/nu11092205] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 09/06/2019] [Accepted: 09/09/2019] [Indexed: 01/09/2023] Open
Abstract
d-amino acids, the enantiomeric counterparts of l-amino acids, were long considered to be non-functional or not even present in living organisms. Nowadays, d-amino acids are acknowledged to play important roles in numerous physiological processes in the human body. The most commonly studied link between d-amino acids and human physiology concerns the contribution of d-serine and d-aspartate to neurotransmission. These d-amino acids and several others have also been implicated in regulating innate immunity and gut barrier function. Importantly, the presence of certain d-amino acids in the human body has been linked to several diseases including schizophrenia, amyotrophic lateral sclerosis, and age-related disorders such as cataract and atherosclerosis. Furthermore, increasing evidence supports a role for d-amino acids in the development, pathophysiology, and treatment of cancer. In this review, we aim to provide an overview of the various sources of d-amino acids, their metabolism, as well as their contribution to physiological processes and diseases in man, with a focus on cancer.
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Affiliation(s)
- Jacco J.A.J. Bastings
- Department of Surgery, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, 6200 MD Maastricht, The Netherlands (H.M.v.E.); (S.W.O.D.)
- Department of Human Biology, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, 6200 MD Maastricht, The Netherlands
| | - Hans M. van Eijk
- Department of Surgery, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, 6200 MD Maastricht, The Netherlands (H.M.v.E.); (S.W.O.D.)
| | - Steven W. Olde Damink
- Department of Surgery, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, 6200 MD Maastricht, The Netherlands (H.M.v.E.); (S.W.O.D.)
- Department of General, Visceral and Transplantation Surgery, RWTH University Hospital Aachen, 52074 Aachen, Germany
| | - Sander S. Rensen
- Department of Surgery, NUTRIM School of Nutrition and Translational Research in Metabolism, Maastricht University, 6200 MD Maastricht, The Netherlands (H.M.v.E.); (S.W.O.D.)
- Correspondence:
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20
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The levels of the NMDA receptor co-agonist D-serine are reduced in the substantia nigra of MPTP-lesioned macaques and in the cerebrospinal fluid of Parkinson's disease patients. Sci Rep 2019; 9:8898. [PMID: 31222058 PMCID: PMC6586824 DOI: 10.1038/s41598-019-45419-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 06/03/2019] [Indexed: 01/31/2023] Open
Abstract
Dysfunction of NMDA receptor (NMDAR)-mediated transmission is supposed to contribute to the motor and non-motor symptoms of Parkinson’s Disease (PD), and to L-DOPA-induced dyskinesia. Besides the main agonist L-glutamate, two other amino acids in the atypical D-configuration, D-serine and D-aspartate, activate NMDARs. In the present work, we investigated the effect of dopamine depletion on D-amino acids metabolism in the brain of MPTP-lesioned Macaca mulatta, and in the serum and cerebrospinal fluid of PD patients. We found that MPTP treatment increases D-aspartate and D-serine in the monkey putamen while L-DOPA rescues both D-amino acids levels. Conversely, dopaminergic denervation is associated with selective D-serine reduction in the substantia nigra. Such decrease suggests that the beneficial effect of D-serine adjuvant therapy previously reported in PD patients may derive from the normalization of endogenous D-serine levels and consequent improvement of nigrostriatal hypoglutamatergic transmission at glycine binding site. We also found reduced D-serine concentration in the cerebrospinal fluid of L-DOPA-free PD patients. These results further confirm the existence of deep interaction between dopaminergic and glutamatergic neurotransmission in PD and disclose a possible direct influence of D-amino acids variations in the changes of NMDAR transmission occurring under dopamine denervation and L-DOPA therapy.
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21
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Pollegioni L, Sacchi S, Murtas G. Human D-Amino Acid Oxidase: Structure, Function, and Regulation. Front Mol Biosci 2018; 5:107. [PMID: 30547037 PMCID: PMC6279847 DOI: 10.3389/fmolb.2018.00107] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 11/12/2018] [Indexed: 12/11/2022] Open
Abstract
D-Amino acid oxidase (DAAO) is an FAD-containing flavoenzyme that catalyzes with absolute stereoselectivity the oxidative deamination of all natural D-amino acids, the only exception being the acidic ones. This flavoenzyme plays different roles during evolution and in different tissues in humans. Its three-dimensional structure is well conserved during evolution: minute changes are responsible for the functional differences between enzymes from microorganism sources and those from humans. In recent years several investigations focused on human DAAO, mainly because of its role in degrading the neuromodulator D-serine in the central nervous system. D-Serine is the main coagonist of N-methyl D-aspartate receptors, i.e., excitatory amino acid receptors critically involved in main brain functions and pathologic conditions. Human DAAO possesses a weak interaction with the FAD cofactor; thus, in vivo it should be largely present in the inactive, apoprotein form. Binding of active-site ligands and the substrate stabilizes flavin binding, thus pushing the acquisition of catalytic competence. Interestingly, the kinetic efficiency of the enzyme on D-serine is very low. Human DAAO interacts with various proteins, in this way modulating its activity, targeting, and cell stability. The known properties of human DAAO suggest that its activity must be finely tuned to fulfill a main physiological function such as the control of D-serine levels in the brain. At present, studies are focusing on the epigenetic modulation of human DAAO expression and the role of post-translational modifications on its main biochemical properties at the cellular level.
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Affiliation(s)
- Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
| | - Silvia Sacchi
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
| | - Giulia Murtas
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
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22
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Ball J, Gannavaram S, Gadda G. Structural determinants for substrate specificity of flavoenzymes oxidizing d-amino acids. Arch Biochem Biophys 2018; 660:87-96. [PMID: 30312594 DOI: 10.1016/j.abb.2018.10.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 10/01/2018] [Accepted: 10/08/2018] [Indexed: 12/26/2022]
Abstract
The oxidation of d-amino acids is relevant to neurodegenerative diseases, detoxification, and nutrition in microorganisms and mammals. It is also important for the resolution of racemic amino acid mixtures and the preparation of chiral building blocks for the pharmaceutical and food industry. Considerable biochemical and structural knowledge has been accrued in recent years on the enzymes that carry out the oxidation of the Cα-N bond of d-amino acids. These enzymes contain FAD as a required coenzyme, share similar overall three-dimensional folds and highly conserved active sites, but differ in their specificity for substrates with neutral, anionic, or cationic side-chains. Here, we summarize the current biochemical and structural knowledge regarding substrate specificity on d-amino acid oxidase, d-aspartate oxidase, and d-arginine dehydrogenase for which a wealth of biochemical and structural studies is available.
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Affiliation(s)
- Jacob Ball
- Departments of Chemistry, Georgia State University, Atlanta, GA, 30302-3965, USA
| | - Swathi Gannavaram
- Departments of Chemistry, Georgia State University, Atlanta, GA, 30302-3965, USA
| | - Giovanni Gadda
- Departments of Chemistry, Georgia State University, Atlanta, GA, 30302-3965, USA; Departments of Biology, Georgia State University, Atlanta, GA, 30302-3965, USA; Center for Biotechnology and Drug Design, Georgia State University, Atlanta, GA, 30302-3965, USA; Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, GA, 30302-3965, USA.
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23
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Szilágyi B, Ferenczy GG, Keserű GM. Drug discovery strategies and the preclinical development of D-amino-acid oxidase inhibitors as antipsychotic therapies. Expert Opin Drug Discov 2018; 13:973-982. [DOI: 10.1080/17460441.2018.1524459] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Bence Szilágyi
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - György G. Ferenczy
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - György M. Keserű
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
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24
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Sacchi S, Cappelletti P, Murtas G. Biochemical Properties of Human D-amino Acid Oxidase Variants and Their Potential Significance in Pathologies. Front Mol Biosci 2018; 5:55. [PMID: 29946548 PMCID: PMC6005901 DOI: 10.3389/fmolb.2018.00055] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 05/23/2018] [Indexed: 12/11/2022] Open
Abstract
The stereoselective flavoenzyme D-amino acid oxidase (DAAO) catalyzes the oxidative deamination of neutral and polar D-amino acids producing the corresponding α-keto acids, ammonia, and hydrogen peroxide. Despite its peculiar and atypical substrates, DAAO is widespread expressed in most eukaryotic organisms. In mammals (and humans in particular), DAAO is involved in relevant physiological processes ranging from D-amino acid detoxification in kidney to neurotransmission in the central nervous system, where DAAO is responsible of the catabolism of D-serine, a key endogenous co-agonist of N-methyl-D-aspartate receptors. Recently, structural and functional studies have brought to the fore the distinctive biochemical properties of human DAAO (hDAAO). It appears to have evolved to allow a strict regulation of its activity, so that the enzyme can finely control the concentration of substrates (such as D-serine in the brain) without yielding to an excessive production of hydrogen peroxide, a potentially toxic reactive oxygen species (ROS). Indeed, dysregulation in D-serine metabolism, likely resulting from altered levels of hDAAO expression and activity, has been implicated in several pathologies, ranging from renal disease to neurological, neurodegenerative, and psychiatric disorders. Only one mutation in DAO gene was unequivocally associated to a human disease. However, several single nucleotide polymorphisms (SNPs) are reported in the database and the biochemical characterization of the corresponding recombinant hDAAO variants is of great interest for investigating the effect of mutations. Here we reviewed recently published data focusing on the modifications of the structural and functional properties induced by amino acid substitutions encoded by confirmed SNPs and on their effect on D-serine cellular levels. The potential significance of the different hDAAO variants in human pathologies will be also discussed.
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Affiliation(s)
- Silvia Sacchi
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy.,The Protein Factory, Politecnico di Milano and Università degli Studi dell'Insubria, Milan, Italy
| | - Pamela Cappelletti
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy.,The Protein Factory, Politecnico di Milano and Università degli Studi dell'Insubria, Milan, Italy
| | - Giulia Murtas
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell'Insubria, Varese, Italy
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