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Stankovic S, Lazic A, Parezanovic M, Stevanovic M, Pavlovic S, Stojiljkovic M, Klaassen K. Transcriptome Profiling of Phenylalanine-Treated Human Neuronal Model: Spotlight on Neurite Impairment and Synaptic Connectivity. Int J Mol Sci 2024; 25:10019. [PMID: 39337507 PMCID: PMC11431966 DOI: 10.3390/ijms251810019] [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: 07/30/2024] [Revised: 09/03/2024] [Accepted: 09/09/2024] [Indexed: 09/30/2024] Open
Abstract
Phenylketonuria (PKU) is the most common inherited disorder of amino acid metabolism, characterized by high levels of phenylalanine (Phe) in the blood and brain, leading to cognitive impairment without treatment. Nevertheless, Phe-mediated brain dysfunction is not fully understood. The objective of this study was to address gene expression alterations due to excessive Phe exposure in the human neuronal model and provide molecular advances in PKU pathophysiology. Hence, we performed NT2/D1 differentiation in culture, and, for the first time, we used Phe-treated NT2-derived neurons (NT2/N) as a novel model for Phe-mediated neuronal impairment. NT2/N were treated with 1.25 mM, 2.5 mM, 5 mM, 10 mM, and 30 mM Phe and subjected to whole-mRNA short-read sequencing. Differentially expressed genes (DEGs) were analyzed and enrichment analysis was performed. Under three different Phe concentrations (2.5 mM, 5 mM, and 10 mM), DEGs pointed to the PREX1, LRP4, CDC42BPG, GPR50, PRMT8, RASGRF2, and CDH6 genes, placing them in the context of PKU for the first time. Enriched processes included dendrite and axon impairment, synaptic transmission, and membrane assembly. In contrast to these groups, the 30 mM Phe treatment group clearly represented the neurotoxicity of Phe, exhibiting enrichment in apoptotic pathways. In conclusion, we established NT2/N as a novel model for Phe-mediated neuronal dysfunction and outlined the Phe-induced gene expression changes resulting in neurite impairment and altered synaptic connectivity.
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Affiliation(s)
- Sara Stankovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11042 Belgrade, Serbia; (S.S.); (A.L.); (M.P.); (M.S.); (S.P.); (M.S.)
| | - Andrijana Lazic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11042 Belgrade, Serbia; (S.S.); (A.L.); (M.P.); (M.S.); (S.P.); (M.S.)
| | - Marina Parezanovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11042 Belgrade, Serbia; (S.S.); (A.L.); (M.P.); (M.S.); (S.P.); (M.S.)
| | - Milena Stevanovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11042 Belgrade, Serbia; (S.S.); (A.L.); (M.P.); (M.S.); (S.P.); (M.S.)
- Institute of Physiology and Biochemistry “Ivan Djaja”, Faculty of Biology, University of Belgrade, Studentski trg 16, 11158 Belgrade, Serbia
- Serbian Academy of Sciences and Arts, Kneza Mihaila 35, 11001 Belgrade, Serbia
| | - Sonja Pavlovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11042 Belgrade, Serbia; (S.S.); (A.L.); (M.P.); (M.S.); (S.P.); (M.S.)
| | - Maja Stojiljkovic
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11042 Belgrade, Serbia; (S.S.); (A.L.); (M.P.); (M.S.); (S.P.); (M.S.)
| | - Kristel Klaassen
- Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11042 Belgrade, Serbia; (S.S.); (A.L.); (M.P.); (M.S.); (S.P.); (M.S.)
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2
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Daga KR, Larey AM, Morfin MG, Chen K, Bitarafan S, Carpenter JM, Hynds HM, Hines KM, Wood LB, Marklein RA. Microglia Morphological Response to Mesenchymal Stromal Cell Extracellular Vesicles Demonstrates EV Therapeutic Potential for Modulating Neuroinflammation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.01.601612. [PMID: 39005342 PMCID: PMC11245023 DOI: 10.1101/2024.07.01.601612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/16/2024]
Abstract
Background Mesenchymal stromal cell derived extracellular vesicles (MSC-EVs) are a promising therapeutic for neuroinflammation. MSC-EVs can interact with microglia, the resident immune cells of the brain, to exert their immunomodulatory effects. In response to inflammatory cues, such as cytokines, microglia undergo phenotypic changes indicative of their function e.g. morphology and secretion. However, these changes in response to MSC-EVs are not well understood. Additionally, no disease-relevant screening tools to assess MSC-EV bioactivity exist, which has further impeded clinical translation. Here, we developed a quantitative, high throughput morphological profiling approach to assess the response of microglia to neuroinflammation-relevant signals and whether this morphological response can be used to indicate the bioactivity of MSC-EVs. Results Using an immortalized human microglia cell-line, we observed increased size (perimeter, major axis length) and complexity (form factor) upon stimulation with interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α). Upon treatment with MSC-EVs, the overall morphological score (determined using principal component analysis) shifted towards the unstimulated morphology, indicating that MSC-EVs are bioactive and modulate microglia. The morphological effects of MSC-EVs in TNF-γ/IFN-α stimulated cells were concomitant with reduced secretion of 14 chemokines/cytokines (e.g. CXCL6, CXCL9) and increased secretion of 12 chemokines/cytokines (e.g. CXCL8, CXCL10). Proteomic analysis of cell lysates revealed significant increases in 192 proteins (e.g. HIBADH, MEAK7, LAMC1) and decreases in 257 proteins (e.g. PTEN, TOM1, MFF) with MSC-EV treatment. Of note, many of these proteins are involved in regulation of cell morphology and migration. Gene Set Variation Analysis revealed upregulation of pathways associated with immune response, such as regulation of cytokine production, immune cell infiltration (e.g. T cells, NK cells) and morphological changes (e.g. Semaphorin, RHO/Rac signaling). Additionally, changes in microglia mitochondrial morphology were measured suggesting that MSC-EV modulate mitochondrial metabolism. Conclusion This study comprehensively demonstrates the effects of MSC-EVs on human microglial morphology, cytokine secretion, cellular proteome, and mitochondrial content. Our high-throughput, rapid, low-cost morphological approach enables screening of MSC-EV batches and manufacturing conditions to enhance EV function and mitigate EV functional heterogeneity in a disease relevant manner. This approach is highly generalizable and can be further adapted and refined based on selection of the disease-relevant signal, target cell, and therapeutic product.
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Affiliation(s)
- Kanupriya R Daga
- School of Chemical, Materials, and Biomedical Engineering, University of Georgia, Athens, GA, USA
- Regenerative Bioscience Center, University of Georgia, Athens, GA, USA
| | - Andrew M Larey
- School of Chemical, Materials, and Biomedical Engineering, University of Georgia, Athens, GA, USA
- Regenerative Bioscience Center, University of Georgia, Athens, GA, USA
| | - Maria G Morfin
- School of Chemical, Materials, and Biomedical Engineering, University of Georgia, Athens, GA, USA
| | - Kailin Chen
- Regenerative Bioscience Center, University of Georgia, Athens, GA, USA
- Franklin College of Arts and Sciences, University of Georgia, Athens, GA, USA
| | - Sara Bitarafan
- George W. Woodruff School of Mechanical Engineering and Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | | | - Hannah M Hynds
- Department of Chemistry, University of Georgia, Athens, GA, USA
| | - Kelly M Hines
- Department of Chemistry, University of Georgia, Athens, GA, USA
| | - Levi B Wood
- George W. Woodruff School of Mechanical Engineering and Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, USA
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA, USA
| | - Ross A Marklein
- School of Chemical, Materials, and Biomedical Engineering, University of Georgia, Athens, GA, USA
- Regenerative Bioscience Center, University of Georgia, Athens, GA, USA
- Center for Biologics Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD, USA
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Wang X, Chen J, Xu H, Fan Y, Wang X, Zhang M, Liu Y, Li B, Liu J, Zhou H. Construction of an ultrasensitive dual-mode chiral molecules sensing platform based on molecularly imprinted polymer modified bipolar electrode. Biosens Bioelectron 2024; 243:115759. [PMID: 37857064 DOI: 10.1016/j.bios.2023.115759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 10/09/2023] [Accepted: 10/12/2023] [Indexed: 10/21/2023]
Abstract
Chiral molecules are abundant in nature. Phenylketonuria (PKU) is caused by the abnormal transformation of chiral molecules L-phenylalanine (L-Phe) in the human blood, which can cause irreversible harm to the human body. In this work, we documented an electrochemiluminescent (ECL) dual-mode sensor platform based on molecularly imprinted polymer (MIP) modified closed bipolar electrodes for high sensitivity detection of L-Phe and D-phenylalanine (D-Phe). In the anode chamber of a bipolar electrode modified with phenylalanine imprinting, Ru (bpy)32+ underwent a redox reaction to produce a chemiluminescence response under the stimulation of a driving voltage. At the same time, the reduction of the cathode film of the bipolar electrode was promoted, and the color changed from dark blue to nearly white. Thus, the dual-mode detection of target molecules is realized. The detection range of the sensor for phenylalanine reached 0.01-10,000 nM, and the detection limits of L-Phe and D-Phe were 3.9 pM and 4.6 pM (S/N = 3), respectively. This dual-mode system achieved high stability and high specificity, and also successfully realized the detection of actual samples, which is expected to achieve future clinical applications.
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Affiliation(s)
- Xinli Wang
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, Shandong Key Laboratory of Biochemical Analysis, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Jiahe Chen
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, Shandong Key Laboratory of Biochemical Analysis, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Hui Xu
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, Shandong Key Laboratory of Biochemical Analysis, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Yufei Fan
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, Shandong Key Laboratory of Biochemical Analysis, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Xue Wang
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, Shandong Key Laboratory of Biochemical Analysis, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Meng Zhang
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, Shandong Key Laboratory of Biochemical Analysis, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Yue Liu
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, Shandong Key Laboratory of Biochemical Analysis, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China
| | - Binxiao Li
- Department of Chemistry, Shanghai Stomatological Hospital, State Key Laboratory of Molecular Engineering of Polymers and Institute of Biomedical Sciences, Fudan University, Shanghai, 200433, PR China.
| | - Jing Liu
- College of Chemical and Biological Engineering, Shandong University of Science and Technology, Qingdao, Shandong, 266590, PR China.
| | - Hong Zhou
- Key Laboratory of Optic-electric Sensing and Analytical Chemistry for Life Science, Ministry of Education, Shandong Key Laboratory of Biochemical Analysis, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao, 266042, PR China.
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Theron M, Jeannesson E, Canton M, Namour F, Oussalah A, Feillet F, Wiedemann A. Blood phenylalanine fluctuation in phenylketonuric children treated by BH4 or low-phenylalanine diet from birth. Sci Rep 2023; 13:9559. [PMID: 37308610 DOI: 10.1038/s41598-023-36550-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2022] [Accepted: 06/06/2023] [Indexed: 06/14/2023] Open
Abstract
The prognosis of phenylketonuria (PKU) is related to the quality of metabolic control all life-long. PKU treatment is based on a low-Phe diet, 6R-tetrahydrobiopterin (BH4) treatment for the BH4-responsive PKU patients or enzyme replacement therapy. Fluctuations in blood phenylalanine (Phe) concentrations may be an important determinant of intellectual outcome in patients with early and continuously treated phenylketonuria (PKU). The aim of this work is to study the fluctuation of Blood Phe in patients treated by BH4 from birth in comparison with patients treated by low-Phe diet. We conducted a retrospective study in a national reference center for PKU management. We compared mean phenylalanine blood concentration and its fluctuation in 10 BH4-responder patients (BH4R) and in 10 BH4 non-responder patients (BH4NR) treated from birth. The mean blood Phe concentration is similar between the two groups before 10 years of age (290 ± 135 (BH4R) vs. 329 ± 187 µmol/L, p = 0.066 (BH4NR)) while it is lower in the BH4R group after 10 years of age. (209 ± 69 vs. 579 ± 136 µmol/L, p = 0.0008). Blood Phe fluctuation is significantly lower in the BH4R group compared to the BH4NR group (70.2 ± 75.6 vs. 104.4 ± 111.6 µmol/L, p < 0.01) before 6 years of age. There are no significant differences observed on nutritional status, growth, and neuropsychological tests between the two groups. BH4 introduced in the neonatal period is associated with less blood Phe fluctuation before 6 years. Additional time and patients are required to determine if the decrease in Phe fluctuation would positively impact the long-term outcome of PKU patients.
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Affiliation(s)
- Maurane Theron
- Pediatric Unit, Reference Center for Inborn Errors of Metabolism, University Hospital of Nancy, Nancy, France
| | - Elise Jeannesson
- Department of Molecular Medicine, Division of Biochemistry, University Hospital of Nancy, Nancy, France
- INSERM UMR_S 1256, Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, Nancy, France
| | - Marie Canton
- Pediatric Unit, Reference Center for Inborn Errors of Metabolism, University Hospital of Nancy, Nancy, France
| | - Farès Namour
- Department of Molecular Medicine, Division of Biochemistry, University Hospital of Nancy, Nancy, France
- INSERM UMR_S 1256, Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, Nancy, France
| | - Abderrahim Oussalah
- Department of Molecular Medicine, Division of Biochemistry, University Hospital of Nancy, Nancy, France
- INSERM UMR_S 1256, Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, Nancy, France
| | - François Feillet
- Pediatric Unit, Reference Center for Inborn Errors of Metabolism, University Hospital of Nancy, Nancy, France.
- INSERM UMR_S 1256, Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, Nancy, France.
| | - Arnaud Wiedemann
- Pediatric Unit, Reference Center for Inborn Errors of Metabolism, University Hospital of Nancy, Nancy, France
- INSERM UMR_S 1256, Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, Nancy, France
- Pediatric Intensive Care Unit, University Hospital of Nancy, Nancy, France
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Rovelli V, Longo N. Phenylketonuria and the brain. Mol Genet Metab 2023; 139:107583. [PMID: 37105048 DOI: 10.1016/j.ymgme.2023.107583] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 04/14/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023]
Abstract
Classic phenylketonuria (PKU) is caused by defective activity of phenylalanine hydroxylase (PAH), the enzyme that coverts phenylalanine (Phe) to tyrosine. Toxic accumulation of phenylalanine and its metabolites, left untreated, affects brain development and function depending on the timing of exposure to elevated levels. The specific mechanisms of Phe-induced brain damage are not completely understood, but they correlate to phenylalanine levels and on the stage of brain growth. During fetal life, high levels of phenylalanine such as those seen in maternal PKU can result in microcephaly, neuronal loss and corpus callosum hypoplasia. Elevated phenylalanine levels during the first few years of life can cause acquired microcephaly, severe cognitive impairment and epilepsy, likely due to the impairment of synaptogenesis. During late childhood, elevated phenylalanine can cause alterations in neurological functioning, leading to ADHD, speech delay and mild IQ reduction. In adolescents and adults, executive function and mood are affected, with some of the abnormalities reversed by better control of phenylalanine levels. Altered brain myelination can be present at this stage. In this article, we review the current knowledge about the consequences of high phenylalanine levels in PKU patients and animal models through different stages of brain development and its effect on cognitive, behavioural and neuropsychological function.
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Affiliation(s)
- Valentina Rovelli
- Clinical Department of Pediatrics, University of Milan, ASST Santi Paolo e Carlo, San Paolo Hospital, Milan, Italy.
| | - Nicola Longo
- Division of Medical Genetics, Department of Pediatrics, University of Utah, Salt Lake City, UT, USA
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Thau-Zuchman O, Pallier PN, Savelkoul PJM, Kuipers AAM, Verkuyl JM, Michael-Titus AT. High phenylalanine concentrations induce demyelination and microglial activation in mouse cerebellar organotypic slices. Front Neurosci 2022; 16:926023. [PMID: 36248632 PMCID: PMC9559601 DOI: 10.3389/fnins.2022.926023] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 09/05/2022] [Indexed: 11/29/2022] Open
Abstract
Phenylketonuria (PKU) is an inborn error of metabolism. Mutations in the enzyme phenylalanine hydroxylase (PAH)-encoding gene lead to a decreased metabolism of the amino acid phenylalanine (Phe). The deficiency in PAH increases Phe levels in blood and brain. Accumulation of Phe can lead to delayed development, psychiatric problems and cognitive impairment. White matter (WM) damage is a neuropathological hallmark of PKU and can be seen even in early detected and treated PKU patients. The mechanisms linking high Phe concentrations to WM abnormalities remain unclear. We tested the effects of high Phe concentrations on myelin in three in vitro models of increasing complexity: two simple cell culture models and one model that preserves local brain tissue architecture, a cerebellar organotypic slice culture prepared from postnatal day (P) 8 CD-1 mice. Various Phe concentrations (0.1–10 mM) and durations of exposure were tested. We found no toxic effect of high Phe in the cell culture models. On the contrary, the treatment promoted the maturation of oligodendrocytes, particularly at the highest, non-physiological Phe concentrations. Exposure of cerebellar organotypic slices to 2.4 mM Phe for 21 days in vitro (DIV), but not 7 or 10 DIV, resulted in a significant decrease in myelin basic protein (MBP), calbindin-stained neurites, and neurites co-stained with MBP. Following exposure to a toxic concentration of Phe, a switch to the control medium for 7 days did not lead to remyelination, while very active remyelination was seen in slices following demyelination with lysolecithin. An enhanced number of microglia, displaying an activated type morphology, was seen after exposure of the slices to 2.4 mM Phe for 10 or 21 DIV. The results suggest that prolonged exposure to high Phe concentrations can induce microglial activation preceding significant disruption of myelin.
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Affiliation(s)
- Orli Thau-Zuchman
- Centre for Neuroscience, Surgery and Trauma, Barts and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
| | - Patrick N. Pallier
- Centre for Neuroscience, Surgery and Trauma, Barts and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
- *Correspondence: Patrick N. Pallier,
| | | | | | | | - Adina T. Michael-Titus
- Centre for Neuroscience, Surgery and Trauma, Barts and The London School of Medicine and Dentistry, The Blizard Institute, Queen Mary University of London, London, United Kingdom
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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: 25] [Impact Index Per Article: 12.5] [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
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Imad A. AlJahdali
- Department of Community Medicine, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Iman S. Abumansour
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Ezzeldin N. Elhawary
- Faculty of Medicine, MS Genomic Medicine Program, University of Southampton, Southampton General Hospital, Southampton, UK
| | - Nagwa Gaboon
- Department 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
- Department 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
- Department of Medical Genetics, College of Medicine, Umm Al-Qura University, P.O. Box 57543, Mecca, 21955 Saudi Arabia
| | - Osama A. Kensara
- Department 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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Erimban S, Daschakraborty S. How does excess phenylalanine affect the packing density and fluidity of a lipid membrane? Phys Chem Chem Phys 2021; 23:27294-27303. [PMID: 34850794 DOI: 10.1039/d1cp05004d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phenylketonuria (PKU) is an autosomal recessive error of phenylalanine (Phe) metabolism, where untreated Phe becomes cytotoxic. Previous experiments found that excess Phe decreases the packing density and increases the fluidity and permeability of a lipid membrane. It was proposed that Phe forms cytotoxic nanoscopic amyloid-like fibrils. In another study, the Phe fibrils were not visible near the lipid membrane. So, what leads to the deleterious effect of Phe on the lipid membrane? We put forward a molecular mechanism for the observed effect of excess Phe on the lipid membrane using all-atom molecular dynamics simulation. This study suggests that Phe monomers spontaneously intercalate into the membrane and form small hydrogen-bonded clusters, some of which locally perturb the membrane. These local effects result in an overall reduction in the membrane packing density, enhancement of membrane fluidity, and an increase of water permeability, observed in experiments. The present study does not observe any effect of the nanoscopic fibrillar structure of Phe on the membrane. This study, therefore, provides alternative insights into the excess Phe cytotoxicity in PKU disease.
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Affiliation(s)
- Shakkira Erimban
- Department of Chemistry, Indian Institute of Technology Patna, Bihar, 801106, India.
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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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Gallo M, Ferrara L, Calogero A, Montesano D, Naviglio D. Relationships between food and diseases: What to know to ensure food safety. Food Res Int 2020; 137:109414. [DOI: 10.1016/j.foodres.2020.109414] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2020] [Revised: 05/21/2020] [Accepted: 06/04/2020] [Indexed: 02/07/2023]
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Lu L, Xia Z, Guo J, Xiao L, Zhang Y. Metabolomics analysis reveals perturbations of cerebrocortical metabolic pathways in the Pah enu2 mouse model of phenylketonuria. CNS Neurosci Ther 2020; 26:486-493. [PMID: 31471952 PMCID: PMC7080435 DOI: 10.1111/cns.13214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2019] [Revised: 07/26/2019] [Accepted: 08/10/2019] [Indexed: 01/03/2023] Open
Abstract
AIMS Phenylketonuria (PKU), which is caused by mutations in the phenylalanine hydroxylase (PAH) gene, is one of the most common inherited diseases of amino acid metabolism. Phenylketonuria is characterized by an abnormal accumulation of phenylalanine and its metabolites in body fluids and brain tissues, subsequently leading to severe brain dysfunction. Various pathophysiological and molecular mechanisms underlying brain dysfunction in PKU have been described. However, the metabolic changes and their impacts on the function of cerebral cortices of patients with PKU remain largely unknown. METHODS We measured the levels of small molecule metabolites in the cerebrocortical tissues of PKU mice and wild-type control mice using liquid chromatography-mass spectrometry (LC-MS)-based metabolome analysis. Differential metabolites were further subjected to metabolic pathway and enrichment analysis. RESULTS Metabolome analysis revealed 35 compounds among 143 detected metabolites were significantly changed in PKU mice as compared to those in their wild-type littermates. Metabolic pathway and enrichment analysis of these differential metabolites showed that multiple metabolic pathways, including phenylalanine, tyrosine, and tryptophan biosynthesis; valine, leucine, and isoleucine biosynthesis; alanine, aspartate, and glutamate metabolism; purine metabolism; arginine and proline metabolism and methionine metabolism, were impacted in the cerebral cortices of PKU mice. CONCLUSIONS The data revealed that multiple metabolic pathways in cerebral cortices of PKU mice were disturbed, suggesting that the disturbances of the metabolic pathways might contribute to neurological or neurodevelopmental dysfunction in PKU, which could thus provide new insights into brain pathogenic mechanisms in PKU as well as mechanistic insights for better understanding the complexity of the metabolic mechanisms of the brain dysfunction in PKU.
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Affiliation(s)
- Li‐Hua Lu
- Department of NeonatologyShanghai First Maternity and Infant Hospital, Tongji University School of MedicineShanghaiChina
| | - Zheng‐Xiang Xia
- Department of Pharmacy, Shanghai Engineering Research Center of Tooth Restoration and RegenerationSchool & Hospital of Stomatology, Tongji UniversityShanghaiChina
| | - Jia‐Lin Guo
- Department of NeonatologyShanghai First Maternity and Infant Hospital, Tongji University School of MedicineShanghaiChina
| | - Ling‐Ling Xiao
- Department of NeonatologyObstetrics and Gynecology Hospital of Fudan UniversityShanghaiChina
| | - Yong‐Jun Zhang
- Department of NeonatologyXinhua Hospital, Shanghai Jiaotong University School of MedicineShanghaiChina
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12
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Feng S, Mei J, Yang L, Luo P, Wang X, Wang Y, Yao J, Cui L, Pan L, Wang Z, Xin L. Benzene Derivatives from Ink Lead to False Positive Results in Neonatal Hyperphenylalaninemia Screening with Ninhydrin Fluorometric Method. Int J Neonatal Screen 2020; 6:14. [PMID: 33073012 PMCID: PMC7422975 DOI: 10.3390/ijns6010014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/18/2020] [Indexed: 11/16/2022] Open
Abstract
Ninhydrin-based fluorometric quantification of phenylalanine is one of the most widely used methods for hyperphenylalaninemia (HPA) screening in neonates due to its high sensitivity, high accuracy, and low cost. Here we report an increase of false positive cases in neonatal HPA screening with this method, caused by contamination of blood specimen collection devices during the printing process. Through multiple steps of verification, the contaminants were identified from ink circles printed on the collection devices to indicate the positions and sizes of blood drops. Blood specimens from HPA-negative persons collected on these contaminated collection devices showed positive results in the fluorometric tests, but negative results in tandem mass spectroscopy (MS/MS) experiments. Contaminants on the collection devices could be extracted by 80% ethanol and showed an absorption peak around 245 nm, suggesting that these contaminants may contain benzene derivatives with similar structure to phenylalanine. High-performance liquid chromatography (HPLC) analysis of the ethanol extracts from contaminated collection devices identified two prominent peaks specifically from the devices. Methyl-2-benzoylbenzoate (MBB, CAS#606-28-0) was found as one of the major chemicals from contaminated collection devices. This report aims to remind colleagues in the field of this potential contamination and call for tighter regulation and quality control of specimen collection devices.
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Affiliation(s)
- Shuren Feng
- Tianjin Women's and Children's Health Centre, Tianjin 300070, China; (J.Y.); (L.C.); (L.P.); (L.X.)
| | - Joanne Mei
- Newborn Screening and Molecular Biology Branch, Division of Laboratory Sciences, Centers for Disease Control and Prevention, Atlanta, GA 30341, USA;
| | - Lu Yang
- Department of Biology, College of Life Sciences, Tianjin University, Tianjin 300072, China; (L.Y.); (Z.W.)
| | - Ping Luo
- Department of Basic Medicine, Tianjin Medical College, Tianjin 300222, China;
| | - Xiaonan Wang
- Tianjin Medical Laboratory, BGI-Tianjin, BGI-Shenzhen, Tianjin 300308, China;
| | - Yuan Wang
- Binhai Genomics Institute, BGI-Tianjin, BGI-Shenzhen, Tianjin 300308, China;
| | - Jingyi Yao
- Tianjin Women's and Children's Health Centre, Tianjin 300070, China; (J.Y.); (L.C.); (L.P.); (L.X.)
| | - Lan Cui
- Tianjin Women's and Children's Health Centre, Tianjin 300070, China; (J.Y.); (L.C.); (L.P.); (L.X.)
| | - Lei Pan
- Tianjin Women's and Children's Health Centre, Tianjin 300070, China; (J.Y.); (L.C.); (L.P.); (L.X.)
| | - Zefang Wang
- Department of Biology, College of Life Sciences, Tianjin University, Tianjin 300072, China; (L.Y.); (Z.W.)
| | - Li Xin
- Tianjin Women's and Children's Health Centre, Tianjin 300070, China; (J.Y.); (L.C.); (L.P.); (L.X.)
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13
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Ashe K, Kelso W, Farrand S, Panetta J, Fazio T, De Jong G, Walterfang M. Psychiatric and Cognitive Aspects of Phenylketonuria: The Limitations of Diet and Promise of New Treatments. Front Psychiatry 2019; 10:561. [PMID: 31551819 PMCID: PMC6748028 DOI: 10.3389/fpsyt.2019.00561] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 07/17/2019] [Indexed: 12/30/2022] Open
Abstract
Phenylketonuria (PKU) is a recessive disorder of phenylalanine metabolism due to mutations in the gene for phenylalanine hydroxylase (PAH). Reduced PAH activity results in significant hyperphenylalaninemia, which leads to alterations in cerebral myelin and protein synthesis, as well as reduced levels of serotonin, dopamine, and noradrenaline in the brain. When untreated, brain development is grossly disrupted and significant intellectual impairment and behavioral disturbance occur. The advent of neonatal heel prick screening has allowed for diagnosis at birth, and the institution of a phenylalanine restricted diet. Dietary treatment, particularly when maintained across neurodevelopment and well into adulthood, has resulted in markedly improved outcomes at a cognitive and psychiatric level for individuals with PKU. However, few individuals can maintain full dietary control lifelong, and even with good control, an elevated risk remains of-in particular-mood, anxiety, and attentional disorders across the lifespan. Increasingly, dietary recommendations focus on maintaining continuous dietary treatment lifelong to optimize psychiatric and cognitive outcomes, although the effect of long-term protein restricted diets on brain function remains unknown. While psychiatric illness is very common in adult PKU populations, very little data exist to guide clinicians on optimal treatment. The advent of new treatments that do not require restrictive dietary management, such as the enzyme therapy Pegvaliase, holds the promise of allowing patients a relatively normal diet alongside optimized mental health and cognitive functioning.
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Affiliation(s)
- Killian Ashe
- Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Wendy Kelso
- Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Sarah Farrand
- Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Julie Panetta
- Statewide Adult Metabolic Service, Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Tim Fazio
- Statewide Adult Metabolic Service, Royal Melbourne Hospital, Melbourne, VIC, Australia.,Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia
| | - Gerard De Jong
- Statewide Adult Metabolic Service, Royal Melbourne Hospital, Melbourne, VIC, Australia.,Melbourne Medical School, University of Melbourne, Melbourne, VIC, Australia
| | - Mark Walterfang
- Neuropsychiatry Unit, Royal Melbourne Hospital, Melbourne, VIC, Australia.,Melbourne Neuropsychiatry Centre, University of Melbourne and North-Western Mental Health, Melbourne, VIC, Australia.,Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
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14
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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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15
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van der Goot E, Bruinenberg VM, Hormann FM, Eisel ULM, van Spronsen FJ, Van der Zee EA. Hippocampal microglia modifications in C57Bl/6 Pah enu2 and BTBR Pah enu2 phenylketonuria (PKU) mice depend on the genetic background, irrespective of disturbed sleep patterns. Neurobiol Learn Mem 2018; 160:139-143. [PMID: 29772389 DOI: 10.1016/j.nlm.2018.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 05/08/2018] [Accepted: 05/12/2018] [Indexed: 12/14/2022]
Abstract
Toxic levels of phenylalanine in blood and brain is a characteristic of (untreated) phenylketonuria (PKU), leading to cognitive deficits in PKU mice. In addition, our recent findings showed that PKU mice (as well as PKU patients) have a disturbed sleep/wake cycle. As a consequence, sleep loss may contribute to cognitive deficits in PKU. Sleep loss has been linked to increased activation of microglia in the hippocampus. In this study, we set out to examine morphological features of the microglia population in the hippocampus of the mouse PKU model, using both the C57Bl/6 and the BTBR strain and their wild-type controls (age 5.3 ± 0.5 months; n = 16 per group, both males and females; n = 8 each). Microglial activation is reflected by retraction and thickening of the dendritic branches and an increase in cell body size of a microglial cell. Such morphological changes of microglia were studied by way of immunohistochemical staining for Iba-1, a microglia-specific calcium binding protein. We measured the number of microglia in seven subregions of the dorsal hippocampus. The level of microglial activation was determined, based on the ratio between the soma size and total cell size (soma size plus the area covered by the dendritic branches). Results showed subtle but statistical significant activation of hippocampal microglia in the C57Bl6, but not in the BTBR, PKU mice when compared with their wild-type controls. Also the total number of microglia was higher in the C57Bl/6 PKU (compared to the wild-type) mouse, but not in the BTBR PKU mouse. It is concluded that the C57Bl/6 PKU mouse has mildly higher microglia activity, which may support rather than hamper hippocampal homeostasis. The results further indicate that high levels of phenylalanine or disturbed sleep patterns do not consequently cause hippocampal microglial activation in the PKU mouse. It is currently unknown why the two PKU mouse strains show these differences in number and activation level of their hippocampal microglia, and to what extent it influences hippocampal functioning. Further scrutinizing the role of microglia functioning in the context of PKU is therefore warranted.
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Affiliation(s)
- Els van der Goot
- Groningen Institute for Evolutionary Life Sciences (GELIFES), Molecular Neurobiology, University of Groningen, Groningen, The Netherlands
| | - Vibeke M Bruinenberg
- Groningen Institute for Evolutionary Life Sciences (GELIFES), Molecular Neurobiology, University of Groningen, Groningen, The Netherlands
| | - Femke M Hormann
- Groningen Institute for Evolutionary Life Sciences (GELIFES), Molecular Neurobiology, University of Groningen, Groningen, The Netherlands
| | - Ulrich L M Eisel
- Groningen Institute for Evolutionary Life Sciences (GELIFES), Molecular Neurobiology, University of Groningen, Groningen, The Netherlands
| | - Francjan J van Spronsen
- Division of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center of Groningen, University of Groningen, Groningen, The Netherlands
| | - Eddy A Van der Zee
- Groningen Institute for Evolutionary Life Sciences (GELIFES), Molecular Neurobiology, University of Groningen, Groningen, The Netherlands.
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16
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Intrinsic property of phenylalanine to trigger protein aggregation and hemolysis has a direct relevance to phenylketonuria. Sci Rep 2017; 7:11146. [PMID: 28894147 PMCID: PMC5593866 DOI: 10.1038/s41598-017-10911-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/15/2017] [Indexed: 01/31/2023] Open
Abstract
Excess accumulation of phenylalanine is the characteristic of untreated Phenylketonuria (PKU), a well-known genetic abnormality, which triggers several neurological, physical and developmental severities. However, the fundamental mechanism behind the origin of such diverse health problems, particularly the issue of how they are related to the build-up of phenylalanine molecules in the body, is largely unknown. Here, we show cross-seeding ability of phenylalanine fibrils that can effectively initiate an aggregation process in proteins under physiological conditions, converting native protein structures to β-sheet assembly. The resultant fibrils were found to cause severe hemolysis, yielding a plethora of deformed erythrocytes that is highly relevant to phenylketonuria. Unique arrangement of zwitterionic phenylalanine molecules in their amyloid-like higher order entities is predicted to promote both hydrophobic and electrostatic interaction, sufficient enough to trap proteins and to preferentially interact with the membrane components of RBCs. Since the prevalence of hemolysis and amyloid related psychoneurological severities are mostly observed in PKU patients, we propose that the inherent property of phenylalanine fibrils to trigger hemolysis and to induce protein aggregation may have direct relevance to the disease mechanism of PKU.
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17
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Bruinenberg VM, van der Goot E, van Vliet D, de Groot MJ, Mazzola PN, Heiner-Fokkema MR, van Faassen M, van Spronsen FJ, van der Zee EA. The Behavioral Consequence of Phenylketonuria in Mice Depends on the Genetic Background. Front Behav Neurosci 2016; 10:233. [PMID: 28066199 PMCID: PMC5167755 DOI: 10.3389/fnbeh.2016.00233] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 11/28/2016] [Indexed: 12/31/2022] Open
Abstract
To unravel the role of gene mutations in the healthy and the diseased state, countless studies have tried to link genotype with phenotype. However, over the years, it became clear that the strain of mice can influence these results. Nevertheless, identical gene mutations in different strains are often still considered equals. An example of this, is the research done in phenylketonuria (PKU), an inheritable metabolic disorder. In this field, a PKU mouse model (either on a BTBR or C57Bl/6 background) is often used to examine underlying mechanisms of the disease and/or new treatment strategies. Both strains have a point mutation in the gene coding for the enzyme phenylalanine hydroxylase which causes toxic concentrations of the amino acid phenylalanine in blood and brain, as found in PKU patients. Although the mutation is identical and therefore assumed to equally affect physiology and behavior in both strains, no studies directly compared the two genetic backgrounds to test this assumption. Therefore, this study compared the BTBR and C57Bl/6 wild-type and PKU mice on PKU-relevant amino acid- and neurotransmitter-levels and at a behavioral level. The behavioral paradigms were selected from previous literature on the PKU mouse model and address four domains, namely (1) activity levels, (2) motor performance, (3) anxiety and/or depression-like behavior, and (4) learning and memory. The results of this study showed comparable biochemical changes in phenylalanine and neurotransmitter concentrations. In contrast, clear differences in behavioral outcome between the strains in all four above-mentioned domains were found, most notably in the learning and memory domain. The outcome in this domain seem to be primarily due to factors inherent to the genetic background of the mouse and much less by differences in PKU-specific biochemical parameters in blood and brain. The difference in behavioral outcome between PKU of both strains emphasizes that the consequence of the PAH mutation is influenced by other factors than Phe levels alone. Therefore, future research should consider these differences when choosing one of the genetic strains to investigate the pathophysiological mechanism underlying PKU-related behavior, especially when combined with new treatment strategies.
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Affiliation(s)
- Vibeke M Bruinenberg
- Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences, University of Groningen Groningen, Netherlands
| | - Els van der Goot
- Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences, University of Groningen Groningen, Netherlands
| | - Danique van Vliet
- Department of Pediatrics, Beatrix Children's Hospital, University Medical Center Groningen Groningen, Netherlands
| | - Martijn J de Groot
- Department of Pediatrics, Beatrix Children's Hospital, University Medical Center Groningen Groningen, Netherlands
| | - Priscila N Mazzola
- Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences, University of GroningenGroningen, Netherlands; Department of Pediatrics, Beatrix Children's Hospital, University Medical Center GroningenGroningen, Netherlands
| | | | - Martijn van Faassen
- Laboratory Medicine, University of Groningen, University Medical Center Groningen, Netherlands
| | - Francjan J van Spronsen
- Department of Pediatrics, Beatrix Children's Hospital, University Medical Center Groningen Groningen, Netherlands
| | - Eddy A van der Zee
- Molecular Neurobiology, Groningen Institute for Evolutionary Life Sciences, University of Groningen Groningen, Netherlands
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