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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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Lotz-Havla AS, Katzdobler S, Nuscher B, Weiß K, Levin J, Havla J, Maier EM. Serum glial fibrillary acidic protein and neurofilament light chain in patients with early treated phenylketonuria. Front Neurol 2022; 13:1011470. [PMID: 36247773 PMCID: PMC9559705 DOI: 10.3389/fneur.2022.1011470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 09/12/2022] [Indexed: 12/01/2022] Open
Abstract
To pave the way for healthy aging in early treated phenylketonuria (ETPKU) patients, a better understanding of the neurological course in this population is needed, requiring easy accessible biomarkers to monitor neurological disease progression in large cohorts. The objective of this pilot study was to investigate the potential of glial fibrillary acidic protein (GFAP) and neurofilament light chain (NfL) as blood biomarkers to indicate changes of the central nervous system in ETPKU. In this single-center cross-sectional study, GFAP and NfL concentrations in serum were quantified using the Simoa® multiplex technology in 56 ETPKU patients aged 6–36 years and 16 age matched healthy controls. Correlation analysis and hierarchical linear regression analysis were performed to investigate an association with disease-related biochemical parameters and retinal layers assessed by optical coherence tomography. ETPKU patients did not show significantly higher GFAP concentrations (mean 73 pg/ml) compared to healthy controls (mean 60 pg/ml, p = 0.140). However, individual pediatric and adult ETPKU patients had GFAP concentrations above the healthy control range. In addition, there was a significant association of GFAP concentrations with current plasma tyrosine concentrations (r = −0.482, p = 0.036), a biochemical marker in phenylketonuria, and the retinal inner nuclear layer volume (r = 0.451, p = 0.04). There was no evidence of NfL alterations in our ETPKU cohort. These pilot results encourage multicenter longitudinal studies to further investigate serum GFAP as a complementary tool to better understand and monitor neurological disease progression in ETPKU. Follow-up investigations on aging ETPKU patients are required to elucidate the potential of serum NfL as biomarker.
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Affiliation(s)
- Amelie S. Lotz-Havla
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU Munich, Munich, Germany
| | - Sabrina Katzdobler
- Department of Neurology, University Hospital, LMU Munich, Munich, Germany
| | - Brigitte Nuscher
- Department of Neurology, University Hospital, LMU Munich, Munich, Germany
| | - Katharina Weiß
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU Munich, Munich, Germany
| | - Johannes Levin
- Department of Neurology, University Hospital, LMU Munich, Munich, Germany
- German Center for Neurodegenerative Diseases, site Munich, Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Joachim Havla
- Institute of Clinical Neuroimmunology, University Hospital, LMU Munich, Munich, Germany
- Data Integration for Future Medicine (DIFUTURE) Consortium, LMU Munich, Munich, Germany
- *Correspondence: Joachim Havla
| | - Esther M. Maier
- Department of Pediatrics, Dr. von Hauner Children's Hospital, University Hospital, LMU Munich, Munich, Germany
- Esther M. Maier
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Alves MMS, Leandro P, Mertens HDT, Pereiro AB, Archer M. Impact of Fluorinated Ionic Liquids on Human Phenylalanine Hydroxylase-A Potential Drug Delivery System. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:893. [PMID: 35335706 PMCID: PMC8950220 DOI: 10.3390/nano12060893] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 03/03/2022] [Accepted: 03/04/2022] [Indexed: 12/16/2022]
Abstract
Phenylketonuria (PKU) is an autosomal recessive disease caused by deficient activity of human phenylalanine hydroxylase (hPAH), which can lead to neurologic impairments in untreated patients. Although some therapies are already available for PKU, these are not without drawbacks. Enzyme-replacement therapy through the delivery of functional hPAH could be a promising strategy. In this work, biophysical methods were used to evaluate the potential of [N1112(OH)][C4F9SO3], a biocompatible fluorinated ionic liquid (FIL), as a delivery system of hPAH. The results herein presented show that [N1112(OH)][C4F9SO3] spontaneously forms micelles in a solution that can encapsulate hPAH. This FIL has no significant effect on the secondary structure of hPAH and is able to increase its enzymatic activity, despite the negative impact on protein thermostability. The influence of [N1112(OH)][C4F9SO3] on the complex oligomerization equilibrium of hPAH was also assessed.
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Affiliation(s)
- Márcia M. S. Alves
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal;
- LAQV, REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (FCT NOVA), 2829-516 Caparica, Portugal
| | - Paula Leandro
- Research Institute for Medicines (iMed.Ulisboa) and Department of Pharmaceutical Sciences and Medicines, Faculdade de Farmácia, Universidade de Lisboa, 1649-003 Lisbon, Portugal;
| | - Haydyn D. T. Mertens
- European Molecular Biology Lamboratory (EMBL), Hamburg Unit c/o Deutches Elektronen Synchrotron (DESY), D-22607 Hamburg, Germany;
| | - Ana B. Pereiro
- LAQV, REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade Nova de Lisboa (FCT NOVA), 2829-516 Caparica, Portugal
| | - Margarida Archer
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), 2780-157 Oeiras, Portugal;
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Development of vascular disease models to explore disease causation and pathomechanisms of rare vascular diseases. Semin Immunopathol 2022; 44:259-268. [PMID: 35233690 PMCID: PMC8887661 DOI: 10.1007/s00281-022-00925-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 02/10/2022] [Indexed: 12/15/2022]
Abstract
As the field of medicine is striving forward heralded by a new era of next-generation sequencing (NGS) and integrated technologies such as bioprinting and biological material development, the utility of rare monogenetic vascular disease modeling in this landscape is starting to emerge. With their genetic simplicity and broader applicability, these patient-specific models are at the forefront of modern personalized medicine. As a collective, rare diseases are a significant burden on global healthcare systems, and rare vascular diseases make up a significant proportion of this. High costs are due to a lengthy diagnostic process, affecting all ages from infants to adults, as well as the severity and chronic nature of the disease. Their complex nature requires sophisticated disease models and integrated approaches involving multidisciplinary teams. Here, we review these emerging vascular disease models, how they contribute to our understanding of the pathomechanisms in rare vascular diseases and provide useful platforms for therapeutic discovery.
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