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Bourne LE, Davies BK, Millan JL, Arnett TR, Wheeler-Jones CPD, Keen JAC, Roberts SJ, Orriss IR. Evidence that pyrophosphate acts as an extracellular signalling molecule to exert direct functional effects in primary cultures of osteoblasts and osteoclasts. Bone 2023; 176:116868. [PMID: 37549801 DOI: 10.1016/j.bone.2023.116868] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/04/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023]
Abstract
Extracellular pyrophosphate (PPi) is well known for its fundamental role as a physiochemical mineralisation inhibitor. However, information about its direct actions on bone cells remains limited. This study shows that PPi decreased osteoclast formation and resorptive activity by ≤50 %. These inhibitory actions were associated with reduced expression of genes involved in osteoclastogenesis (Tnfrsf11a, Dcstamp) and bone resorption (Ctsk, Car2, Acp5). In osteoblasts, PPi present for the entire (0-21 days) or latter stages of culture (7-21/14-21 days) decreased bone mineralisation by ≤95 %. However, PPi present for the differentiation phase only (0-7/0-14 days) increased bone formation (≤70 %). Prolonged treatment with PPi resulted in earlier matrix deposition and increased soluble collagen levels (≤2.3-fold). Expression of osteoblast (RUNX2, Bglap) and early osteocyte (E11, Dmp1) genes along with mineralisation inhibitors (Spp1, Mgp) was increased by PPi (≤3-fold). PPi levels are regulated by tissue non-specific alkaline phosphatase (TNAP) and ecto-nucleotide pyrophosphatase/phosphodiesterase 1 (NPP1). PPi reduced NPP1 expression in both cell types whereas TNAP expression (≤2.5-fold) and activity (≤35 %) were increased in osteoblasts. Breakdown of extracellular ATP by NPP1 represents a key source of PPi. ATP release from osteoclasts and osteoblasts was decreased ≤60 % by PPi and by a selective TNAP inhibitor (CAS496014-12-2). Pertussis toxin, which prevents Gαi subunit activation, was used to investigate whether G-protein coupled receptor (GPCR) signalling mediates the effects of PPi. The actions of PPi on bone mineralisation, collagen production, ATP release, gene/protein expression and osteoclast formation were abolished or attenuated by pertussis toxin. Together these findings show that PPi, modulates differentiation, function and gene expression in osteoblasts and osteoclasts. The ability of PPi to alter ATP release and NPP1/TNAP expression and activity indicates that cells can detect PPi levels and respond accordingly. Our data also raise the possibility that some actions of PPi on bone cells could be mediated by a Gαi-linked GPCR.
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Affiliation(s)
- Lucie E Bourne
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK; School of Applied Sciences, University of Brighton, UK
| | - Bethan K Davies
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK; Clinical and Experimental Endocrinology, KU, Leuven, Belgium
| | - Jose Luis Millan
- Sanford-Burnham Prebys Medical Discovery Institute, La Jolla, USA
| | - Timothy R Arnett
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK; Department of Cell and Developmental Biology, University College London, London, UK
| | | | - Jacob A C Keen
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Scott J Roberts
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK
| | - Isabel R Orriss
- Department of Comparative Biomedical Sciences, Royal Veterinary College, London, UK.
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2
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Tao X, Yang C, He J, Liu Q, Wu S, Tang W, Wang J. Serum alkaline phosphatase was independently associated with depression in patients with cerebrovascular disease. Front Psychiatry 2023; 14:1184673. [PMID: 37469359 PMCID: PMC10352498 DOI: 10.3389/fpsyt.2023.1184673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 06/16/2023] [Indexed: 07/21/2023] Open
Abstract
Background and purpose Blood markers have important value in the diagnosis of depressive disorders. Serum alkaline phosphatase (ALP) not only predicts stroke recurrence and poor functional prognosis in cerebrovascular disease (CVD) patients but also increases significantly in middle-aged women with depression. Thus, it has not been reported whether serum ALP is associated with the development of depression and/or vascular depression (VDe) in CVD patients. Methods This was a cross-sectional study of 353 CVD patients (stroke patients, n = 291; cerebral small vessel disease (CSVD) patients, n = 62). Baseline demographic information, fasting blood markers (such as blood counts, liver function, kidney function and lipids), and brain CT/MRI scans were collected. CVD patients were divided into non-depression, suspected vascular depression (SVD), and positive vascular depression (PVD) groups according to their Hamilton Rating Scale for Depression (HAMD) scores. Univariate analysis of baseline data, blood markers, and the prevalence of lesions (> 1.5 cm) was performed. Subsequently, the diagnostic performance of the univariate and combined variables for SVD and PVD was analyzed using binary logistic regression. The diagnostic value of the multivariate model for VDe was analyzed by ordinal logistic regression. Results (1) Serum ALP (p = 0.003) and hypersensitive C-reactive protein (hs-CRP, p = 0.001) concentrations increased as HAMD scores increased, and the prevalence of brain atrophy (p = 0.016) and lesions in the basal ganglia (p = 0.001) and parietal (p = 0.001), temporal (p = 0.002), and frontal lobes (p = 0.003) also increased, whereas the concentrations of hemoglobin (Hb, p = 0.003), cholinesterase (ChE, p = 0.001), and high-density lipoprotein cholesterol (HDL-C, p = 0.005) declined. Among these variables, hs-CRP (r = 0.218, p < 0.001) had a weak positively association with HAMD scores, and ChE (r = -0.226, p < 0.001) had a weak negative association. (2) The combination of Hb, hs-CRP, ChE, ALP, and HDL-C improved diagnostic performance for VDe [AUC = 0.775, 95% CI (0.706, 0.844), p < 0.001]. (3) Hb (OR = 0.986, p = 0.049), ChE (OR = 0.999, p = 0.020), ALP (OR = 1.017, p = 0.003), and basal ganglia lesions (OR = 2.197, p < 0.001) were important factors impacting VDe development. After adjusting for Hb, hs-CRP, ChE, HDL-C, lesions in the above mentioned four locations, sex, age and the prevalence of CSVD and brain atrophy, ALP [OR = 1.016, 95% CI (1.005, 1.027), p = 0.004] was independently associated with VDe. Conclusion Hb, hs-CRP, ChE, ALP, and HDL-C concentrations are potential blood markers of depression in CVD patients and, when combined, may improve diagnostic performance for VDe. Serum ALP was independently associated with VDe in patients with CVD.
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Affiliation(s)
- Xi Tao
- Department of Neurological Rehabilitation, Hunan Provincial People’s Hospital, Hunan Normal University, Changsha, Hunan Province, China
- Clinical Research Center for Cerebrovascular Disease Rehabilitation in Hunan Province, Changsha, Hunan Province, China
- Hunan Provincical Key Laboratory of Neurorestoratology, Hunan Normal University, Changsha, Hunan, China
| | - Chen Yang
- Department of Neurological Rehabilitation, Hunan Provincial People’s Hospital, Hunan Normal University, Changsha, Hunan Province, China
| | - Juan He
- Department of Neurosurgery, Hunan Provincial People’s Hospital, Hunan Normal University, Changsha, Hunan Province, China
| | - Qianrong Liu
- Department of Neurological Rehabilitation, Hunan Provincial People’s Hospital, Hunan Normal University, Changsha, Hunan Province, China
- Clinical Research Center for Cerebrovascular Disease Rehabilitation in Hunan Province, Changsha, Hunan Province, China
| | - Siyuan Wu
- Department of Neurological Rehabilitation, Hunan Provincial People’s Hospital, Hunan Normal University, Changsha, Hunan Province, China
| | - Wenjing Tang
- Department of Rehabilitation, Rehabilitation Hospital of Hunan Province, Changsha, Hunan Province, China
| | - Jia Wang
- Department of Scientific Research, Hunan Provincial People’s Hospital, Hunan Normal University, Changsha, Hunan Province, China
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Sebastián-Serrano Á, Merchán-Rubira J, Di-Lauro C, Bianchi C, Soria-Tobar L, Narisawa S, Millán JL, Ávila J, Hernández F, Díaz-Hernández M. TNAP upregulation is a critical factor in Tauopathies and its blockade ameliorates neurotoxicity and increases life-expectancy. Neurobiol Dis 2022; 165:105632. [DOI: 10.1016/j.nbd.2022.105632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 12/22/2022] Open
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Sekaran S, Vimalraj S, Thangavelu L. The Physiological and Pathological Role of Tissue Nonspecific Alkaline Phosphatase beyond Mineralization. Biomolecules 2021; 11:1564. [PMID: 34827562 PMCID: PMC8615537 DOI: 10.3390/biom11111564] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Revised: 10/12/2021] [Accepted: 10/12/2021] [Indexed: 12/17/2022] Open
Abstract
Tissue-nonspecific alkaline phosphatase (TNAP) is a key enzyme responsible for skeletal tissue mineralization. It is involved in the dephosphorylation of various physiological substrates, and has vital physiological functions, including extra-skeletal functions, such as neuronal development, detoxification of lipopolysaccharide (LPS), an anti-inflammatory role, bile pH regulation, and the maintenance of the blood brain barrier (BBB). TNAP is also implicated in ectopic pathological calcification of soft tissues, especially the vasculature. Although it is the crucial enzyme in mineralization of skeletal and dental tissues, it is a logical clinical target to attenuate vascular calcification. Various tools and studies have been developed to inhibit its activity to arrest soft tissue mineralization. However, we should not neglect its other physiological functions prior to therapies targeting TNAP. Therefore, a better understanding into the mechanisms mediated by TNAP is needed for minimizing off targeted effects and aid in the betterment of various pathological scenarios. In this review, we have discussed the mechanism of mineralization and functions of TNAP beyond its primary role of hard tissue mineralization.
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Affiliation(s)
- Saravanan Sekaran
- Department of Pharmacology, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College and Hospitals, Saveetha University, Chennai 600 077, Tamil Nadu, India;
| | - Selvaraj Vimalraj
- Department of Pharmacology, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College and Hospitals, Saveetha University, Chennai 600 077, Tamil Nadu, India;
- Centre for Biotechnology, Anna University, Chennai 600 025, Tamil Nadu, India
| | - Lakshmi Thangavelu
- Department of Pharmacology, Saveetha Institute of Medical and Technical Sciences, Saveetha Dental College and Hospitals, Saveetha University, Chennai 600 077, Tamil Nadu, India;
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P2X7 receptor blockade reduces tau induced toxicity, therapeutic implications in tauopathies. Prog Neurobiol 2021; 208:102173. [PMID: 34516970 DOI: 10.1016/j.pneurobio.2021.102173] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 09/02/2021] [Accepted: 09/07/2021] [Indexed: 01/28/2023]
Abstract
Tauopathies are neurodegenerative diseases characterized by the presence of aberrant intraneuronal aggregates of hyperphosphorylated Tau protein. Recent studies suggest that associated chronic neuroinflammation may contribute to the pathological Tau dissemination. However, the underlying molecular mechanisms remain unknown. Since purinergic P2X7 receptors (P2X7) can sense the rise of extracellular ATP levels associated with neuroinflammation, its involvement in neurodegeneration-associated inflammation was suggested. We found a P2X7 upregulation in patients diagnosed with different tauopathies and in a tauopathy mouse model, P301S mice. In vivo pharmacological or genetic blockade of P2X7 reverted microglial activation in P301S mice leading to a reduction in microglial migratory, secretory, and proliferative capacities, and promoting phagocytic function. Furthermore, it reduced the intraneuronal phosphorylated Tau levels in a GSK3-dependent way and increased extracellular phosphorylated Tau levels by reducing the expression of ectoenzyme TNAP. Accordingly, pharmacological or genetic blockade of P2X7 improved the cellular survival, motor and memory deficits and anxiolytic profile in P301S mice. Contrary, P2X7 overexpression caused a significant worsening of Tau-induced toxicity and aggravated the deteriorated motor and memory deficits in P301S mice. Our results indicate that P2X7 plays a deleterious role in tauopathies and suggest that its blockade may be a promising approach to treat Tauopathies.
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Nwafor DC, Brichacek AL, Ali A, Brown CM. Tissue-Nonspecific Alkaline Phosphatase in Central Nervous System Health and Disease: A Focus on Brain Microvascular Endothelial Cells. Int J Mol Sci 2021; 22:5257. [PMID: 34067629 PMCID: PMC8156423 DOI: 10.3390/ijms22105257] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 05/11/2021] [Accepted: 05/12/2021] [Indexed: 12/21/2022] Open
Abstract
Tissue-nonspecific alkaline phosphatase (TNAP) is an ectoenzyme bound to the plasma membranes of numerous cells via a glycosylphosphatidylinositol (GPI) moiety. TNAP's function is well-recognized from earlier studies establishing its important role in bone mineralization. TNAP is also highly expressed in cerebral microvessels; however, its function in brain cerebral microvessels is poorly understood. In recent years, few studies have begun to delineate a role for TNAP in brain microvascular endothelial cells (BMECs)-a key component of cerebral microvessels. This review summarizes important information on the role of BMEC TNAP, and its implication in health and disease. Furthermore, we discuss current models and tools that may assist researchers in elucidating the function of TNAP in BMECs.
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Affiliation(s)
- Divine C. Nwafor
- Department of Neuroscience, School of Medicine, West Virginia University Health Science Center, Morgantown, WV 26506, USA; (D.C.N.); (A.A.)
- Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, USA
| | - Allison L. Brichacek
- Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University Health Science Center, Morgantown, WV 26506, USA;
| | - Ahsan Ali
- Department of Neuroscience, School of Medicine, West Virginia University Health Science Center, Morgantown, WV 26506, USA; (D.C.N.); (A.A.)
- Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, USA
| | - Candice M. Brown
- Department of Neuroscience, School of Medicine, West Virginia University Health Science Center, Morgantown, WV 26506, USA; (D.C.N.); (A.A.)
- Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV 26506, USA
- Department of Microbiology, Immunology, and Cell Biology, School of Medicine, West Virginia University Health Science Center, Morgantown, WV 26506, USA;
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7
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TNAP as a New Player in Chronic Inflammatory Conditions and Metabolism. Int J Mol Sci 2021; 22:ijms22020919. [PMID: 33477631 PMCID: PMC7831495 DOI: 10.3390/ijms22020919] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/14/2021] [Accepted: 01/14/2021] [Indexed: 12/19/2022] Open
Abstract
This review summarizes important information on the ectoenzyme tissue-nonspecific alkaline phosphatase (TNAP) and gives a brief insight into the symptoms, diagnostics, and treatment of the rare disease Hypophosphatasia (HPP), which is resulting from mutations in the TNAP encoding ALPL gene. We emphasize the role of TNAP beyond its well-known contribution to mineralization processes. Therefore, above all, the impact of the enzyme on central molecular processes in the nervous system and on inflammation is presented here.
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8
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Tissue-Nonspecific Alkaline Phosphatase-A Gatekeeper of Physiological Conditions in Health and a Modulator of Biological Environments in Disease. Biomolecules 2020; 10:biom10121648. [PMID: 33302551 PMCID: PMC7763311 DOI: 10.3390/biom10121648] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/30/2020] [Accepted: 12/05/2020] [Indexed: 12/15/2022] Open
Abstract
Tissue-nonspecific alkaline phosphatase (TNAP) is a ubiquitously expressed enzyme that is best known for its role during mineralization processes in bones and skeleton. The enzyme metabolizes phosphate compounds like inorganic pyrophosphate and pyridoxal-5′-phosphate to provide, among others, inorganic phosphate for the mineralization and transportable vitamin B6 molecules. Patients with inherited loss of function mutations in the ALPL gene and consequently altered TNAP activity are suffering from the rare metabolic disease hypophosphatasia (HPP). This systemic disease is mainly characterized by impaired bone and dental mineralization but may also be accompanied by neurological symptoms, like anxiety disorders, seizures, and depression. HPP characteristically affects all ages and shows a wide range of clinical symptoms and disease severity, which results in the classification into different clinical subtypes. This review describes the molecular function of TNAP during the mineralization of bones and teeth, further discusses the current knowledge on the enzyme’s role in the nervous system and in sensory perception. An additional focus is set on the molecular role of TNAP in health and on functional observations reported in common laboratory vertebrate disease models, like rodents and zebrafish.
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9
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Bianchi ML, Bishop NJ, Guañabens N, Hofmann C, Jakob F, Roux C, Zillikens MC. Hypophosphatasia in adolescents and adults: overview of diagnosis and treatment. Osteoporos Int 2020; 31:1445-1460. [PMID: 32162014 DOI: 10.1007/s00198-020-05345-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 02/11/2020] [Indexed: 12/11/2022]
Abstract
This article provides an overview of the current knowledge on hypophosphatasia-a rare genetic disease of very variable presentation and severity-with a special focus on adolescents and adults. It summarizes the available information on the many known mutations of tissue-nonspecific alkaline phosphatase (TNSALP), the epidemiology and clinical presentation of the disease in adolescents and adults, and the essential diagnostic clues. The last section reviews the therapeutic approaches, including recent reports on enzyme replacement therapy (EnzRT).
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Affiliation(s)
- M L Bianchi
- Laboratorio sperimentale di ricerche sul metabolismo osseo infantile, Centro Malattie Metaboliche Ossee, Istituto Auxologico Italiano IRCCS, Milan, Italy.
| | - N J Bishop
- Department of Oncology and Metabolism, University of Sheffield, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - N Guañabens
- Servicio de Reumatología, Hospital Clínic, Universidad de Barcelona, IDIBAPS CIBERehd, Barcelona, Spain
| | - C Hofmann
- Children's Hospital, University of Würzburg, Würzburg, Germany
| | - F Jakob
- Orthopedic Centre for Musculoskeletal Research, University of Würzburg, Würzburg, Germany
| | - C Roux
- INSERM U1153 APHP Centre, Université de Paris, Department of Rheumatology, Paris, France
| | - M C Zillikens
- Department of Internal Medicine, Endocrinology Section, Erasmus Medical Centre, Rotterdam, The Netherlands
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de Diego-García L, Sebastián-Serrano Á, Bianchi C, Di Lauro C, Díaz-Hernández M. ATP Measurement in Cerebrospinal Fluid Using a Microplate Reader. Methods Mol Biol 2020; 2041:233-241. [PMID: 31646493 DOI: 10.1007/978-1-4939-9717-6_17] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Imbalance in extracellular ATP levels in brain tissue has been suggested as a triggering factor for several neurological disorders. Here, we describe the most sensitive and reliable technique for monitoring the ATP levels in mice cerebrospinal samples collected by cisterna magna puncture technique and quantified using a microplate reader.
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Affiliation(s)
- Laura de Diego-García
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.,Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland.,FutureNeuro Research Center, Dublin, Ireland
| | - Álvaro Sebastián-Serrano
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.,Instituto de Investigaciones Biomédicas "Alberto Sols", Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), Madrid, Spain
| | - Carolina Bianchi
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Caterina Di Lauro
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Madrid, Spain.,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
| | - Miguel Díaz-Hernández
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Madrid, Spain. .,Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain.
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11
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Wilson MP, Plecko B, Mills PB, Clayton PT. Disorders affecting vitamin B 6 metabolism. J Inherit Metab Dis 2019; 42:629-646. [PMID: 30671974 DOI: 10.1002/jimd.12060] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 12/12/2018] [Indexed: 12/21/2022]
Abstract
Vitamin B6 is present in our diet in many forms, however, only pyridoxal 5'-phosphate (PLP) can function as a cofactor for enzymes. The intestine absorbs nonphosphorylated B6 vitamers, which are converted by specific enzymes to the active PLP form. The role of PLP is enabled by its reactive aldehyde group. Pathways reliant on PLP include amino acid and neurotransmitter metabolism, folate and 1-carbon metabolism, protein and polyamine synthesis, carbohydrate and lipid metabolism, mitochondrial function and erythropoiesis. Besides the role of PLP as a cofactor B6 vitamers also play other cellular roles, for example, as antioxidants, modifying expression and action of steroid hormone receptors, affecting immune function, as chaperones and as an antagonist of Adenosine-5'-triphosphate (ATP) at P2 purinoceptors. Because of the vital role of PLP in neurotransmitter metabolism, particularly synthesis of the inhibitory transmitter γ-aminobutyric acid, it is not surprising that various inborn errors leading to PLP deficiency manifest as B6 -responsive epilepsy, usually of early onset. This includes pyridox(am)ine phosphate oxidase deficiency (a disorder affecting PLP synthesis and recycling), disorders affecting PLP import into the brain (hypophosphatasia and glycosylphosphatidylinositol anchor synthesis defects), a disorder of an intracellular PLP-binding protein (PLPBP, previously named PROSC) and disorders where metabolites accumulate that inactivate PLP, for example, ALDH7A1 deficiency and hyperprolinaemia type II. Patients with these disorders can show rapid control of seizures in response to either pyridoxine and/or PLP with a lifelong dependency on supraphysiological vitamin B6 supply. The clinical and biochemical features of disorders leading to B6 -responsive seizures and the treatment of these disorders are described in this review.
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Affiliation(s)
- Matthew P Wilson
- Genetics and Genomic Medicine, UCL GOS Institute of Child Health, London, UK
| | - Barbara Plecko
- Department of Pediatrics and Adolescent Medicine, Division of General Pediatrics, University Childrens' Hospital Graz, Medical University Graz, Graz, Austria
| | - Philippa B Mills
- Genetics and Genomic Medicine, UCL GOS Institute of Child Health, London, UK
| | - Peter T Clayton
- Genetics and Genomic Medicine, UCL GOS Institute of Child Health, London, UK
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Sebastián-Serrano Á, de Diego-García L, di Lauro C, Bianchi C, Díaz-Hernández M. Nucleotides regulate the common molecular mechanisms that underlie neurodegenerative diseases; Therapeutic implications. Brain Res Bull 2019; 151:84-91. [PMID: 30721769 DOI: 10.1016/j.brainresbull.2019.01.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/22/2019] [Accepted: 01/30/2019] [Indexed: 02/06/2023]
Abstract
Neurodegenerative diseases (ND) are a heterogeneous group of neurological disorders characterized by a progressive loss of neuronal function which results in neuronal death. Although a specific toxic factor has been identified for each ND, all of them share common pathological molecular mechanisms favouring the disease development. In the final stages of ND, patients become unable to take care of themselves and decline to a total functional incapacitation that leads to their death. Some of the main factors which contribute to the disease progression include proteasomal dysfunction, neuroinflammation, synaptic alterations, protein aggregation, and oxidative stress. Over recent years, evidence has been accumulated to suggest that purinergic signaling plays a key role in the aforementioned molecular pathways. In this review, we revise the implications of the purinergic signaling in the common molecular mechanism underlying the ND. In particular, we focus on the role of the purinergic receptors P2X7, P2Y2 and the ectoenzyme tissue-nonspecific alkaline phosphatase (TNAP).
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Affiliation(s)
- Álvaro Sebastián-Serrano
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Avda. Puerta de Hierro S/N, Madrid, Spain; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, IdISSC, Madrid, Spain
| | - Laura de Diego-García
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Avda. Puerta de Hierro S/N, Madrid, Spain; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, IdISSC, Madrid, Spain
| | - Caterina di Lauro
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Avda. Puerta de Hierro S/N, Madrid, Spain; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, IdISSC, Madrid, Spain
| | - Carolina Bianchi
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Avda. Puerta de Hierro S/N, Madrid, Spain; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, IdISSC, Madrid, Spain
| | - Miguel Díaz-Hernández
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Avda. Puerta de Hierro S/N, Madrid, Spain; Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, IdISSC, Madrid, Spain.
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