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Trefz F, Frauendienst-Egger G, Dienel G, Cannet C, Schmidt-Mader B, Haas D, Blau N, Himmelreich N, Spraul M, Freisinger P, Dobrowolski S, Berg D, Pilotto A. Does hyperphenylalaninemia induce brain glucose hypometabolism? Cerebral spinal fluid findings in treated adult phenylketonuric patients. Mol Genet Metab 2024; 142:108464. [PMID: 38537426 DOI: 10.1016/j.ymgme.2024.108464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 03/21/2024] [Accepted: 03/22/2024] [Indexed: 05/08/2024]
Abstract
Despite numerous studies in human patients and animal models for phenylketonuria (PKU; OMIM#261600), the pathophysiology of PKU and the underlying causes of brain dysfunction and cognitive problems in PKU patients are not well understood. In this study, lumbar cerebral spinal fluid (CSF) was obtained immediately after blood sampling from early-treated adult PKU patients who had fasted overnight. Metabolite and amino acid concentrations in the CSF of PKU patients were compared with those of non-PKU controls. The CSF concentrations and CSF/plasma ratios for glucose and lactate were found to be below normal, similar to what has been reported for glucose transporter1 (GLUT1) deficiency patients who exhibit many of the same clinical symptoms as untreated PKU patients. CSF glucose and lactate levels were negatively correlated with CSF phenylalanine (Phe), while CSF glutamine and glutamate levels were positively correlated with CSF Phe levels. Plasma glucose levels were negatively correlated with plasma Phe concentrations in PKU subjects, which partly explains the reduced CSF glucose concentrations. Although brain glucose concentrations are unlikely to be low enough to impair brain glucose utilization, it is possible that the metabolism of Phe in the brain to produce phenyllactate, which can be transported across the blood-brain barrier to the blood, may consume glucose and/or lactate to generate the carbon backbone for glutamate. This glutamate is then converted to glutamine and carries the Phe-derived ammonia from the brain to the blood. While this mechanism remains to be tested, it may explain the correlations of CSF glutamine, glucose, and lactate concentrations with CSF Phe.
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Affiliation(s)
- Friedrich Trefz
- Heidelberg University, Medical Faculty of Heidelberg, Center for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg, Germany.
| | | | - Gerald Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, AR, United States; Department of Cell Biology and Physiology, University of New Mexico, Albuquerque, NM, United States
| | | | - Brigitte Schmidt-Mader
- Heidelberg University, Medical Faculty of Heidelberg, Center for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg, Germany
| | - Dorothea Haas
- Heidelberg University, Medical Faculty of Heidelberg, Center for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, Heidelberg, Germany
| | - Nenad Blau
- University Children's Hospital Zürich, Zürich, Switzerland
| | | | | | - Peter Freisinger
- Klinikum Reutlingen, Department of Pediatrics, Reutlingen, Germany
| | - Steven Dobrowolski
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA 15224, United States
| | - Daniela Berg
- Department of Neurology, University Hospital of Schleswig-Holstein, Kiel, Germany
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Chen A, Pan Y, Chen J. Clinical, genetic, and experimental research of hyperphenylalaninemia. Front Genet 2023; 13:1051153. [PMID: 36685931 PMCID: PMC9845280 DOI: 10.3389/fgene.2022.1051153] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/06/2022] [Indexed: 01/06/2023] Open
Abstract
Hyperphenylalaninemia (HPA) is the most common amino acid metabolism defect in humans. It is an autosomal-recessive disorder of the phenylalanine (Phe) metabolism, in which high Phe concentrations and low tyrosine (Tyr) concentrations in the blood cause phenylketonuria (PKU), brain dysfunction, light pigmentation and musty odor. Newborn screening data of HPA have revealed that the prevalence varies worldwide, with an average of 1:10,000. Most cases of HPA result from phenylalanine hydroxylase (PAH) deficiency, while a small number of HPA are caused by defects in the tetrahydrobiopterin (BH4) metabolism and DnaJ heat shock protein family (Hsp40) member C12 (DNAJC12) deficiency. Currently, the molecular pathophysiology of the neuropathology associated with HPA remains incompletely understood. Dietary restriction of Phe has been highly successful, although outcomes are still suboptimal and patients find it difficult to adhere to the treatment. Pharmacological treatments, such as BH4 and phenylalanine ammonia lyase, are available. Gene therapy for HPA is still in development.
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Affiliation(s)
- Anqi Chen
- Department of Forensic Medicine, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, China
| | - Yukun Pan
- Barbell Therapeutics Co. Ltd., Shanghai, China,*Correspondence: Yukun Pan, ; Jinzhong Chen,
| | - Jinzhong Chen
- State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Sciences, Fudan University, Shanghai, China,*Correspondence: Yukun Pan, ; Jinzhong Chen,
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Elhawary NA, AlJahdali IA, Abumansour IS, Elhawary EN, Gaboon N, Dandini M, Madkhali A, Alosaimi W, Alzahrani A, Aljohani F, Melibary EM, Kensara OA. Genetic etiology and clinical challenges of phenylketonuria. Hum Genomics 2022; 16:22. [PMID: 35854334 PMCID: PMC9295449 DOI: 10.1186/s40246-022-00398-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/08/2022] [Indexed: 02/08/2023] Open
Abstract
This review discusses the epidemiology, pathophysiology, genetic etiology, and management of phenylketonuria (PKU). PKU, an autosomal recessive disease, is an inborn error of phenylalanine (Phe) metabolism caused by pathogenic variants in the phenylalanine hydroxylase (PAH) gene. The prevalence of PKU varies widely among ethnicities and geographic regions, affecting approximately 1 in 24,000 individuals worldwide. Deficiency in the PAH enzyme or, in rare cases, the cofactor tetrahydrobiopterin results in high blood Phe concentrations, causing brain dysfunction. Untreated PKU, also known as PAH deficiency, results in severe and irreversible intellectual disability, epilepsy, behavioral disorders, and clinical features such as acquired microcephaly, seizures, psychological signs, and generalized hypopigmentation of skin (including hair and eyes). Severe phenotypes are classic PKU, and less severe forms of PAH deficiency are moderate PKU, mild PKU, mild hyperphenylalaninaemia (HPA), or benign HPA. Early diagnosis and intervention must start shortly after birth to prevent major cognitive and neurological effects. Dietary treatment, including natural protein restriction and Phe-free supplements, must be used to maintain blood Phe concentrations of 120-360 μmol/L throughout the life span. Additional treatments include the casein glycomacropeptide (GMP), which contains very limited aromatic amino acids and may improve immunological function, and large neutral amino acid (LNAA) supplementation to prevent plasma Phe transport into the brain. The synthetic BH4 analog, sapropterin hydrochloride (i.e., Kuvan®, BioMarin), is another potential treatment that activates residual PAH, thus decreasing Phe concentrations in the blood of PKU patients. Moreover, daily subcutaneous injection of pegylated Phe ammonia-lyase (i.e., pegvaliase; PALYNZIQ®, BioMarin) has promised gene therapy in recent clinical trials, and mRNA approaches are also being studied.
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Affiliation(s)
- Nasser A. Elhawary
- grid.412832.e0000 0000 9137 6644Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Imad A. AlJahdali
- grid.412832.e0000 0000 9137 6644Department of Community Medicine, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Iman S. Abumansour
- grid.412832.e0000 0000 9137 6644Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Ezzeldin N. Elhawary
- grid.123047.30000000103590315Faculty of Medicine, MS Genomic Medicine Program, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Nagwa Gaboon
- grid.7269.a0000 0004 0621 1570Department of Clinical Genetics, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Mohammed Dandini
- Department of Laboratory and Blood Bank, Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Abdulelah Madkhali
- grid.415254.30000 0004 1790 7311Department of Pathology and Laboratory Medicine, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Wafaa Alosaimi
- Department of Hematology, Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Abdulmajeed Alzahrani
- Department of Laboratory and Blood Bank at Maternity and Children Hospital, Mecca, Saudi Arabia
| | - Fawzia Aljohani
- Department of Pediatric Clinics, Maternity and Children Hospital, King Salman Medical City, Madinah, Saudi Arabia
| | - Ehab M. Melibary
- grid.412832.e0000 0000 9137 6644Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Osama A. Kensara
- grid.412832.e0000 0000 9137 6644Department of Clinical Nutrition, Faculty of Applied Medical Sciences, Umm Al-Qura University, Jeddah, Saudi Arabia
- Department of Biochemistry, Batterjee Medical College, Jeddah, Saudi Arabia
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Song X, Wang X, Liao G, Pan Y, Qian Y, Qiu J. Toxic effects of fipronil and its metabolites on PC12 cell metabolism. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2021; 224:112677. [PMID: 34450423 DOI: 10.1016/j.ecoenv.2021.112677] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 08/11/2021] [Accepted: 08/16/2021] [Indexed: 06/13/2023]
Abstract
Fipronil and its metabolites (fipronil sulfone, fipronil sulfide and fipronil desulfinyl) adversely affect the environment and human health. Targeted metabolomics and lipidomics based on ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was used to analyse the alterations of glycerophospholipids and amino acids after exposure to fipronil and its metabolites at dosages of 0.5, 12.5 and 50 μM for 72 h and to evaluate their different toxic effects. Results showed that fipronil sulfone and fipronil desulfinyl are more toxic than their parent compound, with fipronil desulfinyl as the most toxic and fipronil sulfide as the least toxic. Fipronil and its metabolites affected the metabolism of PC18:1/16:0, PI18:0/20:4, arginine, leucine and tyrosine and the "phenylalanine, tyrosine and tryptophan biosynthesis" pathway, indicating their possible inducing role in cellular macromolecule damage, nerve signal transmission disturbance and energy metabolism disruption caused by oxidative stress. Importantly, fipronil sulfone and fipronil desulfinyl more strongly influenced lipid and amino acid metabolism, mainly reflected in the number of changed glycerophospholipids and differential metabolites associated with oxidative stress, including PS18:0/20:4, glutamate, phenylalanine and histidine for fipronil sulfone and PS18:0/20:4, glutamate, phenylalanine, serine and aspartic acid for fipronil desulfinyl. Therefore, the higher toxicity of fipronil desulfinyl and fipronil sulfone may be also related to oxidative stress. This study provides implications for risk assessment and toxic mechanism research on fipronil and its metabolites.
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Affiliation(s)
- Xiao Song
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture and Rural Affairs, Beijing 100081, China
| | - Xinlu Wang
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture and Rural Affairs, Beijing 100081, China
| | - Guangqin Liao
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture and Rural Affairs, Beijing 100081, China
| | - Yecan Pan
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture and Rural Affairs, Beijing 100081, China
| | - Yongzhong Qian
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture and Rural Affairs, Beijing 100081, China.
| | - Jing Qiu
- Institute of Quality Standards and Testing Technology for Agro-Products, Chinese Academy of Agricultural Sciences, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture and Rural Affairs, Beijing 100081, China.
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Abstract
Phenylketonuria (PKU; also known as phenylalanine hydroxylase (PAH) deficiency) is an autosomal recessive disorder of phenylalanine metabolism, in which especially high phenylalanine concentrations cause brain dysfunction. If untreated, this brain dysfunction results in severe intellectual disability, epilepsy and behavioural problems. The prevalence varies worldwide, with an average of about 1:10,000 newborns. Early diagnosis is based on newborn screening, and if treatment is started early and continued, intelligence is within normal limits with, on average, some suboptimal neurocognitive function. Dietary restriction of phenylalanine has been the mainstay of treatment for over 60 years and has been highly successful, although outcomes are still suboptimal and patients can find the treatment difficult to adhere to. Pharmacological treatments are available, such as tetrahydrobiopterin, which is effective in only a minority of patients (usually those with milder PKU), and pegylated phenylalanine ammonia lyase, which requires daily subcutaneous injections and causes adverse immune responses. Given the drawbacks of these approaches, other treatments are in development, such as mRNA and gene therapy. Even though PAH deficiency is the most common defect of amino acid metabolism in humans, brain dysfunction in individuals with PKU is still not well understood and further research is needed to facilitate development of pathophysiology-driven treatments.
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Affiliation(s)
- Francjan J van Spronsen
- Beatrix Children's Hospital, University Medical Centre Groningen, University of Groningen, Groningen, Netherlands.
| | - Nenad Blau
- University Children's Hospital in Zurich, Zurich, Switzerland
| | - Cary Harding
- Department of Molecular and Medical Genetics and Department of Pediatrics, Oregon Health & Science University, Oregon, USA
| | | | - Nicola Longo
- Department of Pediatrics, University of Utah, Salt Lake City, Utah, USA
| | - Annet M Bosch
- University of Amsterdam, Department of Pediatrics, Division of Metabolic Disorders, Emma Children's Hospital, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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Bortoluzzi VT, Dutra Filho CS, Wannmacher CMD. Oxidative stress in phenylketonuria-evidence from human studies and animal models, and possible implications for redox signaling. Metab Brain Dis 2021; 36:523-543. [PMID: 33580861 DOI: 10.1007/s11011-021-00676-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 01/24/2021] [Indexed: 01/11/2023]
Abstract
Phenylketonuria (PKU) is one of the commonest inborn error of amino acid metabolism. Before mass neonatal screening was possible, and the success of introducing diet therapy right after birth, the typical clinical finds in patients ranged from intellectual disability, epilepsy, motor deficits to behavioral disturbances and other neurological and psychiatric symptoms. Since early diagnosis and treatment became widespread, usually only those patients who do not strictly follow the diet present psychiatric, less severe symptoms such as anxiety, depression, sleep pattern disturbance, and concentration and memory problems. Despite the success of low protein intake in preventing otherwise severe outcomes, PKU's underlying neuropathophysiology remains to be better elucidated. Oxidative stress has gained acceptance as a disturbance implicated in the pathogenesis of PKU. The conception of oxidative stress has evolved to comprehend how it could interfere and ultimately modulate metabolic pathways regulating cell function. We summarize the evidence of oxidative damage, as well as compromised antioxidant defenses, from patients, animal models of PKU, and in vitro experiments, discussing the possible clinical significance of these findings. There are many studies on oxidative stress and PKU, but only a few went further than showing macromolecular damage and disturbance of antioxidant defenses. In this review, we argue that these few studies may point that oxidative stress may also disturb redox signaling in PKU, an aspect few authors have explored so far. The reported effect of phenylalanine on the expression or activity of enzymes participating in metabolic pathways known to be responsive to redox signaling might be mediated through oxidative stress.
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Affiliation(s)
- Vanessa Trindade Bortoluzzi
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, Porto Alegre, RS, CEP 90.035-003, Brazil.
| | - Carlos Severo Dutra Filho
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, Porto Alegre, RS, CEP 90.035-003, Brazil
| | - Clovis Milton Duval Wannmacher
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos 2600-Anexo, Porto Alegre, RS, CEP 90.035-003, Brazil
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Chen S, Sun M, Zhao X, Yang Z, Liu W, Cao J, Qiao Y, Luo X, Wen A. Neuroprotection of hydroxysafflor yellow A in experimental cerebral ischemia/reperfusion injury via metabolic inhibition of phenylalanine and mitochondrial biogenesis. Mol Med Rep 2019; 19:3009-3020. [PMID: 30816517 PMCID: PMC6423596 DOI: 10.3892/mmr.2019.9959] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 01/29/2019] [Indexed: 11/16/2022] Open
Abstract
Stroke is the second most frequent cause of mortality, resulting in a huge societal burden worldwide. Timely reperfusion is the most effective therapy; however, it is difficult to prevent ischemia/reperfusion (I/R) injury. In traditional Chinese medicine, hydroxysafflor yellow A (HSYA) has been widely used for the treatment of cerebrovascular disease and as a protective therapy against I/R injury. Evidence has demonstrated that HSYA could reduce the levels of reactive oxygen species and suppress cellular apoptosis; however, whether HSYA alters the metabolic profile as its underlying mechanism for neuroprotection remains unknown. In the present study, using a metabolomic screening, phenylalanine was identified to significantly increase in an experimental model of mouse cerebral I/R injury. Notably, western blotting and qPCR analysis were conducted to test the expression level of apoptosis-associated factors, and HSYA was identified to be able to protect neuronal cells by reducing phenylalanine level associated with I/R injury. Additionally, these findings were confirmed in primary mouse neurons and PC12 cells exposed to oxygen and glucose deprivation/reoxygenation (OGD/R) stress. Of note, HSYA was observed to regulate the mRNA expression of key metabolic enzymes, phenylalanine hydroxylase, tyrosine aminotransferase and aspartate aminotransferase, which are responsible for phenylalanine metabolism. Furthermore, by performing mitochondrial labeling and JC-1 fluorescence assay, HSYA was identified to promote mitochondrial function and biogenesis suppressed by OGD/R. The findings of the present study demonstrated that I/R injury could increase the levels of phenylalanine, and HSYA may inhibit phenylalanine synthesis to enhance mitochondrial function and biogenesis for neuroprotection. The present study proposed a novel metabolite biomarker for cerebral I/R injury and the evaluated the efficacy of HSYA as a potential therapeutic treatment I/R injury.
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Affiliation(s)
- Suning Chen
- Department of Pharmacy, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Mao Sun
- Department of Biochemistry and Molecular Biology, Center for DNA Typing, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Xianghui Zhao
- Institute of Neuroscience, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Zhifu Yang
- Department of Pharmacy, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Wenxing Liu
- Department of Pharmacy, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Jinyi Cao
- Department of Pharmacy, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Yi Qiao
- Department of Pharmacy, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Xiaoxing Luo
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
| | - Aidong Wen
- Department of Pharmacy, Xijing Hospital, The Fourth Military Medical University, Xi'an, Shaanxi 710032, P.R. China
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Lu L, Ben X, Xiao L, Peng M, Zhang Y. AMP-activated protein kinase activation in mediating phenylalanine-induced neurotoxicity in experimental models of phenylketonuria. J Inherit Metab Dis 2018; 41:679-687. [PMID: 29230603 DOI: 10.1007/s10545-017-0115-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 10/18/2022]
Abstract
Phenylketonuria (PKU), one of the most prevalent autosomal recessive disorders of amino acid metabolism, is characterized by abnormal accumulation of phenylalanine, which can lead to intellectual disability. The main pathologic changes in the central nervous system of untreated phenylketonuric patients are reductions in the number of axons, dendrites, and synapses in the brain. Such alterations are thought to be mainly associated with the toxic effects caused by phenylalanine. However, the underlying molecular mechanisms have not been fully elucidated. The present study shows that a high concentration of phenylalanine remarkably inhibited neuronal neurite formation in vitro. Interestingly, AMP-activated protein kinase (AMPK), the energy status sensor, was activated in cultured cerebral cortical neurons upon phenylalanine treatment. Pretreatment with an AMPK inhibitor ameliorated the reduction of neurite formation caused by phenylalanine. In addition, the levels of the phosphorylated AMPK, the active form of AMPK, were significantly higher in the cerebral cortices of PKU mice with elevated phenylalanine levels in this brain region compared to those in wild-type control mice, whereas the density of dendritic spines on basal secondary dendrites of pyramidal neurons in prefrontal cortices of PKU mice was significantly decreased. Collectively, these findings indicate that AMPK activation is a key event in impaired neuronal dendritic development in PKU and consequently, a potential therapeutic target for developing neuroprotective strategies against phenylalanine-evoked brain injury in PKU.
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Affiliation(s)
- Lihua Lu
- Department of Neonatology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Xiaoming Ben
- Department of Neonatology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Lingling Xiao
- Department of Neonatology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China
| | - Min Peng
- Department of Neonatology, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, China
| | - Yongjun Zhang
- Department of Neonatology, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, 1665 Kongjiang Road, Shanghai, 200092, People's Republic of China.
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Ditamo Y, Dentesano YM, Purro SA, Arce CA, Bisig CG. Post-Translational Incorporation of L-Phenylalanine into the C-Terminus of α-Tubulin as a Possible Cause of Neuronal Dysfunction. Sci Rep 2016; 6:38140. [PMID: 27905536 PMCID: PMC5131269 DOI: 10.1038/srep38140] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 11/07/2016] [Indexed: 11/23/2022] Open
Abstract
α-Tubulin C-terminus undergoes post-translational, cyclic tyrosination/detyrosination, and L-Phenylalanine (Phe) can be incorporated in place of tyrosine. Using cultured mouse brain-derived cells and an antibody specific to Phe-tubulin, we showed that: (i) Phe incorporation into tubulin is reversible; (ii) such incorporation is not due to de novo synthesis; (iii) the proportion of modified tubulin is significant; (iv) Phe incorporation reduces cell proliferation without affecting cell viability; (v) the rate of neurite retraction declines as level of C-terminal Phe incorporation increases; (vi) this inhibitory effect of Phe on neurite retraction is blocked by the co-presence of tyrosine; (vii) microtubule dynamics is reduced when Phe-tubulin level in cells is high as a result of exogenous Phe addition and returns to normal values when Phe is removed; moreover, microtubule dynamics is also reduced when Phe-tubulin is expressed (plasmid transfection). It is known that Phe levels are greatly elevated in blood of phenylketonuria (PKU) patients. The molecular mechanism underlying the brain dysfunction characteristic of PKU is unknown. Beyond the differences between human and mouse cells, it is conceivable the possibility that Phe incorporation into tubulin is the first event (or among the initial events) in the molecular pathways leading to brain dysfunctions that characterize PKU.
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Affiliation(s)
- Yanina Ditamo
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC-CONICET, and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
| | - Yanela M Dentesano
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC-CONICET, and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
| | - Silvia A Purro
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC-CONICET, and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
| | - Carlos A Arce
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC-CONICET, and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
| | - C Gastón Bisig
- Centro de Investigaciones en Química Biológica de Córdoba, CIQUIBIC-CONICET, and Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, X5000HUA, Córdoba, Argentina
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10
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Li D, Gu X, Lu L, Liang L. Effects of phenylalanine on the survival and neurite outgrowth of rat cortical neurons in primary cultures: possible involvement of brain-derived neurotrophic factor. Mol Cell Biochem 2010; 339:1-7. [PMID: 20101519 DOI: 10.1007/s11010-009-0364-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2009] [Accepted: 12/16/2009] [Indexed: 12/15/2022]
Abstract
Phenylketonuria (PKU) is characterized by elevated levels of phenylalanine (Phe) in plasma and cerebrospinal fluid of PKU patients, leading to mental retardation. The developmental delay in the cerebral cortex is one of the characteristic pathologic changes in untreated phenylketonuria patients. This is thought to be due to the toxic effects of Phe and/or its metabolites; however, the underlying mechanisms are as yet unknown. In this study, using a model system in which cultured cortical neurons were induced with Phe, we observed that Phe inhibited the longest neurite outgrowth and induced the neuronal death. We further demonstrated that the expression of BDNF mRNA and protein was significantly decreased by Phe, together with a decrease in extracellular signal-regulated kinase (ERK) and Akt phosphorylation activity. There was no change in expression of TrkB mRNA and protein. Considering the important role of BDNF in normal brain development and function, these L: -Phe-induced changes in BDNF in PKU brain may be a critical element of the neurological symptoms of PKU.
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Affiliation(s)
- Duan Li
- Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Institute for Pediatric Research, 1665 Kong Jiang Rd, Shanghai 200092, China.
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11
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High concentrations of phenylalanine stimulate peroxisome proliferator-activated receptor γ: Implications for the pathophysiology of phenylketonuria. Neurobiol Dis 2008; 32:385-90. [DOI: 10.1016/j.nbd.2008.07.020] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2008] [Revised: 07/25/2008] [Accepted: 07/29/2008] [Indexed: 11/17/2022] Open
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Finas D, Huszar M, Agic A, Dogan S, Kiefel H, Riedle S, Gast D, Marcovich R, Noack F, Altevogt P, Fogel M, Hornung D. L1 cell adhesion molecule (L1CAM) as a pathogenetic factor in endometriosis. Hum Reprod 2008; 23:1053-62. [DOI: 10.1093/humrep/den044] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
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Ding XQ, Fiehler J, Kohlschütter B, Wittkugel O, Grzyska U, Zeumer H, Ullrich K. MRI abnormalities in normal-appearing brain tissue of treated adult PKU patients. J Magn Reson Imaging 2008; 27:998-1004. [PMID: 18425822 DOI: 10.1002/jmri.21289] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Xiao-Qi Ding
- Department of Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
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