Untreated phenylketonuria (PKU) patients and PKU animal models show hypomyelination in the central nervous system and white matter damages, which are accompanied by myelin basic protein (MBP) impairment. Despite many assumptions, the primary explanation of the mentioned cerebral outcomes remains elusive. In this study, MBP protein and mRNA expression on brains of wild type (WT) and phenylketonuric (ENU2) mice were analyzed throughout mice lifespan (14-60-180-270-360-540 post-natal days, PND). The results confirmed the low MBP expression at first PND times, while revealed an unprecedented progressive MBP protein expression recovery in aged ENU2 mice. Unexpectedly, unaltered MBP mRNA expression between WT and ENU2 was always observed. Additionally, for the same time intervals, a significant decrease of the phenylalanine concentration in the peripheral blood and brain of ENU2 mice was detected, to date, for the first time. In this scenario, a translational hindrance of MBP during initial and late cerebral development in ENU2 mice was hypothesized, leading to the execution of a microRNA microarray analysis on 60 PND brains, which was followed by a proteomic assay on 60 and 360 PND brains in order to validate in silico miRNA-target predictions. Taken together, miR-218-1-3p, miR-1231-3p and miR-217-5p were considered as the most impactful microRNAs, since a downregulation of their potential targets (MAG, CNTNAP2 and ANLN, respectively) can indirectly lead to a low MBP protein expression. These miRNAs, in addition, follow an opposite expression trend compared to MBP during adulthood, and their target proteins revealed a complete normalization in aged ENU2 mice. In conclusion, these results provide a new perspective on the PKU pathophysiology understanding and on a possible treatment, emphasizing the potential modulating role of differentially expressed microRNAs in MBP expression on PKU brains during PKU mouse lifespan.
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http://dx.doi.org/10.1016/j.nbd.2023.106093 | DOI Listing |
J Inherit Metab Dis
November 2024
Division of Metabolism and Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland.
Mol Genet Metab
October 2024
Department of Biomolecular Sciences, University of Urbino "Carlo Bo", via Ca' Le Suore 2, 61029 Urbino (PU), Italy; EryDel SpA, via Antonio Meucci 3, 20091 Bresso (MI), Italy.
Phenylketonuria (PKU, OMIM 261600) is a genetic disorder caused by a deficiency of the hepatic enzyme phenylalanine hydroxylase (PAH). If left untreated, PKU leads to systemic phenylalanine (Phe) accumulation, which can result in irreversible brain damage and intellectual disabilities. In the last 60 years, early and strict dietary restriction of phenylalanine (Phe) intake proved to prevent the severe clinical phenotype of untreated PKU.
View Article and Find Full Text PDFJ Inherit Metab Dis
July 2024
Fraunhofer-Institut für Molekularbiologie und Angewandte Oekologie IME, Aachen, Germany.
Phenylketonuria (PKU) is a congenital metabolic disorder that causes the systemic elevation of phenylalanine (Phe), which is neurotoxic and teratogenic. PKU is currently incurable, and management involves lifelong adherence to an unpalatable protein-restricted diet based on Phe-free amino acid mixtures. Seeking a palatable dietary alternative, we identified a Bacillus subtilis protein (GSP16O) with a well-balanced but low-Phe amino acid profile.
View Article and Find Full Text PDFJ Inherit Metab Dis
January 2024
Division of Metabolism, University Children's Hospital Zurich and Children's Research Centre, Zurich, Switzerland.
Phenylketonuria (PKU) or hyperphenylalaninemia is considered a paradigm for an inherited (metabolic) liver defect and is, based on murine models that replicate all human pathology, an exemplar model for experimental studies on liver gene therapy. Variants in the PAH gene that lead to hyperphenylalaninemia are never fatal (although devastating if untreated), newborn screening has been available for two generations, and dietary treatment has been considered for a long time as therapeutic and satisfactory. However, significant shortcomings of contemporary dietary treatment of PKU remain.
View Article and Find Full Text PDFNeurobiol Dis
May 2023
Department of Biomolecular Sciences, University of Urbino "Carlo Bo", via Saffi 2, 61029 Urbino, PU, Italy; EryDel SpA, via Antonio Meucci 3, 20091 Bresso, Milan, Italy.
Untreated phenylketonuria (PKU) patients and PKU animal models show hypomyelination in the central nervous system and white matter damages, which are accompanied by myelin basic protein (MBP) impairment. Despite many assumptions, the primary explanation of the mentioned cerebral outcomes remains elusive. In this study, MBP protein and mRNA expression on brains of wild type (WT) and phenylketonuric (ENU2) mice were analyzed throughout mice lifespan (14-60-180-270-360-540 post-natal days, PND).
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