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Vaia Y, Bruschi F, Tagi VM, Tosi M, Montanari C, Zuccotti G, Tonduti D, Verduci E. Microbiota gut-brain axis: implications for pediatric-onset leukodystrophies. Front Nutr 2024; 11:1417981. [PMID: 39070252 PMCID: PMC11272617 DOI: 10.3389/fnut.2024.1417981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 07/02/2024] [Indexed: 07/30/2024] Open
Abstract
Neurodegenerative disorders are a group of diseases characterized by progressive degeneration of the nervous system, leading to a gradual loss of previously acquired motor, sensory and/or cognitive functions. Leukodystrophies are amongst the most frequent childhood-onset neurodegenerative diseases and primarily affect the white matter of the brain, often resulting in neuro-motor disability. Notably, gastrointestinal (GI) symptoms and complications, such as gastroesophageal reflux disease (GERD) and dysphagia, significantly impact patients' quality of life, highlighting the need for comprehensive management strategies. Gut dysbiosis, characterized by microbial imbalance, has been implicated in various GI disorders and neurodegenerative diseases. This narrative review explores the intricate relationship between GI symptoms, Gut Microbiota (GM), and neurodegeneration. Emerging evidence underscores the profound influence of GM on neurological functions via the microbiota gut-brain axis. Animal models have demonstrated alterations in GM composition associated with neuroinflammation and neurodegeneration. Our single-centre experience reveals a high prevalence of GI symptoms in leukodystrophy population, emphasizing the importance of gastroenterological assessment and nutritional intervention in affected children. The bidirectional relationship between GI disorders and neurodegeneration suggests a potential role of gut dysbiosis in disease progression. Prospective studies investigating the GM in leukodystrophies are essential to understand the role of gut-brain axis dysfunction in disease progression and identify novel therapeutic targets. In conclusion, elucidating the interplay between GI disorders, GM, and neurodegeneration holds promise for precision treatments aimed at improving patient outcomes and quality of life.
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Affiliation(s)
- Ylenia Vaia
- C.O.A.L.A. (Center for Diagnosis and Treatment of Leukodystrophies), Unit of Pediatric Neurology, V. Buzzi Children’s Hospital, Milan, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Fabio Bruschi
- C.O.A.L.A. (Center for Diagnosis and Treatment of Leukodystrophies), Unit of Pediatric Neurology, V. Buzzi Children’s Hospital, Milan, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Veronica Maria Tagi
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
- Department of Pediatrics, V. Buzzi Children's Hospital, Milan, Italy
| | - Martina Tosi
- Department of Pediatrics, V. Buzzi Children's Hospital, Milan, Italy
- Department of Health Sciences, University of Milan, Milan, Italy
| | - Chiara Montanari
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
- Department of Pediatrics, V. Buzzi Children's Hospital, Milan, Italy
| | - Gianvincenzo Zuccotti
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
- Department of Pediatrics, V. Buzzi Children's Hospital, Milan, Italy
| | - Davide Tonduti
- C.O.A.L.A. (Center for Diagnosis and Treatment of Leukodystrophies), Unit of Pediatric Neurology, V. Buzzi Children’s Hospital, Milan, Italy
- Department of Biomedical and Clinical Sciences, University of Milan, Milan, Italy
| | - Elvira Verduci
- Department of Health Sciences, University of Milan, Milan, Italy
- Metabolic Diseases Unit, Department of Pediatrics, V. Buzzi Children’s Hospital, University of Milan, Milan, Italy
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White matter microglia heterogeneity in the CNS. Acta Neuropathol 2022; 143:125-141. [PMID: 34878590 DOI: 10.1007/s00401-021-02389-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 11/17/2021] [Accepted: 11/28/2021] [Indexed: 02/07/2023]
Abstract
Microglia, the resident myeloid cells in the central nervous system (CNS) play critical roles in shaping the brain during development, responding to invading pathogens, and clearing tissue debris or aberrant protein aggregations during ageing and neurodegeneration. The original concept that like macrophages, microglia are either damaging (pro-inflammatory) or regenerative (anti-inflammatory) has been updated to a kaleidoscope view of microglia phenotypes reflecting their wide-ranging roles in maintaining homeostasis in the CNS and, their contribution to CNS diseases, as well as aiding repair. The use of new technologies including single cell/nucleus RNA sequencing has led to the identification of many novel microglia states, allowing for a better understanding of their complexity and distinguishing regional variations in the CNS. This has also revealed differences between species and diseases, and between microglia and other myeloid cells in the CNS. However, most of the data on microglia heterogeneity have been generated on cells isolated from the cortex or whole brain, whereas white matter changes and differences between white and grey matter have been relatively understudied. Considering the importance of microglia in regulating white matter health, we provide a brief update on the current knowledge of microglia heterogeneity in the white matter, how microglia are important for the development of the CNS, and how microglial ageing affects CNS white matter homeostasis. We discuss how microglia are intricately linked to the classical white matter diseases such as multiple sclerosis and genetic white matter diseases, and their putative roles in neurodegenerative diseases in which white matter is also affected. Understanding the wide variety of microglial functions in the white matter may provide the basis for microglial targeted therapies for CNS diseases.
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Gruenenfelder FI, McLaughlin M, Griffiths IR, Garbern J, Thomson G, Kuzman P, Barrie JA, McCulloch ML, Penderis J, Stassart R, Nave KA, Edgar JM. Neural stem cells restore myelin in a demyelinating model of Pelizaeus-Merzbacher disease. Brain 2020; 143:1383-1399. [PMID: 32419025 PMCID: PMC7462093 DOI: 10.1093/brain/awaa080] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 01/20/2020] [Accepted: 02/05/2020] [Indexed: 12/13/2022] Open
Abstract
Pelizaeus-Merzbacher disease is a fatal X-linked leukodystrophy caused by mutations in the PLP1 gene, which is expressed in the CNS by oligodendrocytes. Disease onset, symptoms and mortality span a broad spectrum depending on the nature of the mutation and thus the degree of CNS hypomyelination. In the absence of an effective treatment, direct cell transplantation into the CNS to restore myelin has been tested in animal models of severe forms of the disease with failure of developmental myelination, and more recently, in severely affected patients with early disease onset due to point mutations in the PLP1 gene, and absence of myelin by MRI. In patients with a PLP1 duplication mutation, the most common cause of Pelizaeus-Merzbacher disease, the pathology is poorly defined because of a paucity of autopsy material. To address this, we examined two elderly patients with duplication of PLP1 in whom the overall syndrome, including end-stage pathology, indicated a complex disease involving dysmyelination, demyelination and axonal degeneration. Using the corresponding Plp1 transgenic mouse model, we then tested the capacity of transplanted neural stem cells to restore myelin in the context of PLP overexpression. Although developmental myelination and axonal coverage by endogenous oligodendrocytes was extensive, as assessed using electron microscopy (n = 3 at each of four end points) and immunostaining (n = 3 at each of four end points), wild-type neural precursors, transplanted into the brains of the newborn mutants, were able to effectively compete and replace the defective myelin (n = 2 at each of four end points). These data demonstrate the potential of neural stem cell therapies to restore normal myelination and protect axons in patients with PLP1 gene duplication mutation and further, provide proof of principle for the benefits of stem cell transplantation for other fatal leukodystrophies with 'normal' developmental myelination.
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Affiliation(s)
- Fredrik I Gruenenfelder
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Mark McLaughlin
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Ian R Griffiths
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - James Garbern
- Department of Neurology and Center for Molecular Medicine and Genetics, Wayne State University, Detroit, MI 48201, USA
| | - Gemma Thomson
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Peter Kuzman
- Department of Neuropathology, University Clinic Leipzig, D-04103 Leipzig, Germany
| | - Jennifer A Barrie
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.,Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK
| | - Maj-Lis McCulloch
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Jacques Penderis
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK
| | - Ruth Stassart
- Department of Neuropathology, University Clinic Leipzig, D-04103 Leipzig, Germany
| | - Klaus-Armin Nave
- Max Planck Institute for Experimental Medicine, D-37075 Goettingen, Germany
| | - Julia M Edgar
- School of Veterinary Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8TA, UK.,Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, G12 8TA, UK.,Max Planck Institute for Experimental Medicine, D-37075 Goettingen, Germany
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The wmN1 Enhancer Region of the Mouse Myelin Proteolipid Protein Gene (mPlp1) is Indispensable for Expression of an mPlp1-lacZ Transgene in Both the CNS and PNS. Neurochem Res 2019; 45:663-671. [PMID: 31782102 DOI: 10.1007/s11064-019-02919-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Revised: 11/19/2019] [Accepted: 11/22/2019] [Indexed: 10/25/2022]
Abstract
The myelin proteolipid protein gene (PLP1) encodes the most abundant protein in CNS myelin. Expression of the gene must be strictly regulated, as evidenced by human X-linked leukodystrophies resulting from variations in PLP1 copy number, including elevated dosages as well as deletions. Recently, we showed that the wmN1 region in human PLP1 (hPLP1) intron 1 is required to promote high levels of an hPLP1-lacZ transgene in mice, using a Cre-lox approach. The current study tests whether loss of the wmN1 region from a related transgene containing mouse Plp1 (mPlp1) DNA produces similar results. In addition, we investigated the effects of loss of another region (ASE) in mPlp1 intron 1. Previous studies have shown that the ASE is required to promote high levels of mPlp1-lacZ expression by transfection analysis, but had no effect when removed from the native gene in mouse. Whether this is due to compensation by another regulatory element in mPlp1 that was not included in the mPlp1-lacZ constructs, or to differences in methodology, is unclear. Two transgenic mouse lines were generated that harbor mPLP(+)Z/FL. The parental transgene utilizes mPlp1 sequences (proximal 2.3 kb of 5'-flanking DNA to the first 37 bp of exon 2) to drive expression of a lacZ reporter cassette. Here we demonstrate that mPLP(+)Z/FL is expressed in oligodendrocytes, oligodendrocyte precursor cells, olfactory ensheathing cells and neurons in brain, and Schwann cells in sciatic nerve. Loss of the wmN1 region from the parental transgene abolished expression, whereas removal of the ASE had no effect.
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Leukocyte expression profiles reveal gene sets with prognostic value for seizure-free outcome following stereotactic laser amygdalohippocampotomy. Sci Rep 2019; 9:1086. [PMID: 30705324 PMCID: PMC6355811 DOI: 10.1038/s41598-018-37763-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 12/13/2018] [Indexed: 02/08/2023] Open
Abstract
Among patients with intractable epilepsy, the most commonly performed surgical procedure is craniotomy for amygdalohippocampectomy (AH). Stereotactic laser amygdalohippocampotomy (SLAH) has also been recently employed as a minimally invasive treatment for intractable temporal lobe epilepsy (TLE). Among patients treated with AH and SLAH approximately 65% and 54% of patients become seizure-free, respectively. Therefore, selection criteria for surgical candidates with improved prognostic value for post-operative seizure-free outcome are greatly needed. In this study, we perform RNA sequencing (RNA-Seq) on whole blood leukocyte samples taken from 16 patients with intractable TLE prior to SLAH to test the hypothesis that pre-operative leukocyte RNA expression profiles are prognostic for post-operative seizure outcome. Multidimensional scaling analysis of the RNA expression data indicated separate clustering of patients with seizure free (SF) and non-seizure-free (NSF) outcomes. Differential expression (DE) analysis performed on SF versus NSF groups revealed 24 significantly differentially expressed genes (≥2.0-fold change, p-value < 0.05, FDR <0.05). Network and pathway analyses identified differential activation of pathways involved in lipid metabolism, morphology of oligodendrocytes, inflammatory response, and development of astrocytes. These results suggest that pre-operative leukocyte expression profiles have prognostic value for seizure outcome following SLAH.
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Lüders KA, Nessler S, Kusch K, Patzig J, Jung RB, Möbius W, Nave KA, Werner HB. Maintenance of high proteolipid protein level in adult central nervous system myelin is required to preserve the integrity of myelin and axons. Glia 2019; 67:634-649. [PMID: 30637801 DOI: 10.1002/glia.23549] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 09/24/2018] [Accepted: 10/01/2018] [Indexed: 12/20/2022]
Abstract
Proteolipid protein (PLP) is the most abundant integral membrane protein in central nervous system (CNS) myelin. Expression of the Plp-gene in oligodendrocytes is not essential for the biosynthesis of myelin membranes but required to prevent axonal pathology. This raises the question whether the exceptionally high level of PLP in myelin is required later in life, or whether high-level PLP expression becomes dispensable once myelin has been assembled. Both models require a better understanding of the turnover of PLP in myelin in vivo. Thus, we generated and characterized a novel line of tamoxifen-inducible Plp-mutant mice that allowed us to determine the rate of PLP turnover after developmental myelination has been completed, and to assess the possible impact of gradually decreasing amounts of PLP for myelin and axonal integrity. We found that 6 months after targeting the Plp-gene the abundance of PLP in CNS myelin was about halved, probably reflecting that myelin is slowly turned over in the adult brain. Importantly, this reduction by 50% was sufficient to cause the entire spectrum of neuropathological changes previously associated with the developmental lack of PLP, including myelin outfoldings, lamellae splittings, and axonal spheroids. In comparison to axonopathy and gliosis, the infiltration of cytotoxic T-cells was temporally delayed, suggesting a corresponding chronology also in the genetic disorders of PLP-deficiency. High-level abundance of PLP in myelin throughout adult life emerges as a requirement for the preservation of white matter integrity.
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Affiliation(s)
- Katja A Lüders
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, Göttingen, Germany
| | - Stefan Nessler
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, Germany
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Julia Patzig
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Ramona B Jung
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Hauke B Werner
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
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Abstract
Pelizaeus-Merzbacher disease (PMD) is an X-linked disorder caused by mutations in the PLP1 gene, which encodes the proteolipid protein of myelinating oligodendroglia. PMD exhibits phenotypic variability that reflects its considerable genotypic heterogeneity, but all forms of the disease result in central hypomyelination associated with early neurologic dysfunction, progressive deterioration, and ultimately death. PMD has been classified into three major subtypes, according to the age of presentation: connatal PMD, classic PMD, and transitional PMD, combining features of both connatal and classic forms. Two other less severe phenotypes were subsequently described, including the spastic paraplegia syndrome and PLP1-null disease. These disorders may be associated with duplications, as well as with point, missense, and null mutations within the PLP1 gene. A number of clinically similar Pelizaeus-Merzbacher-like disorders (PMLD) are considered in the differential diagnosis of PMD, the most prominent of which is PMLD-1, caused by misexpression of the GJC2 gene encoding connexin-47. No effective therapy for PMD exists. Yet, as a relatively pure central nervous system hypomyelinating disorder, with limited involvement of the peripheral nervous system and little attendant neuronal pathology, PMD is an attractive therapeutic target for neural stem cell and glial progenitor cell transplantation, efforts at which are now underway in a number of centers internationally.
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Affiliation(s)
- M Joana Osório
- Center for Translational Neuromedicine and Department of Neurology, University of Rochester Medical Center, Rochester, NY, United States; Center for Translational Neuromedicine, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark
| | - Steven A Goldman
- Center for Translational Neuromedicine and Department of Neurology, University of Rochester Medical Center, Rochester, NY, United States; Center for Translational Neuromedicine, University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark.
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Lüders KA, Patzig J, Simons M, Nave KA, Werner HB. Genetic dissection of oligodendroglial and neuronalPlp1function in a novel mouse model of spastic paraplegia type 2. Glia 2017; 65:1762-1776. [DOI: 10.1002/glia.23193] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 06/28/2017] [Accepted: 06/29/2017] [Indexed: 12/12/2022]
Affiliation(s)
- Katja A. Lüders
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen 37075 Germany
| | - Julia Patzig
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen 37075 Germany
| | - Mikael Simons
- Cellular Neuroscience; Max Planck Institute of Experimental Medicine; Göttingen 37075 Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen 37075 Germany
| | - Hauke B. Werner
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Göttingen 37075 Germany
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Groh J, Martini R. Neuroinflammation as modifier of genetically caused neurological disorders of the central nervous system: Understanding pathogenesis and chances for treatment. Glia 2017; 65:1407-1422. [PMID: 28568966 DOI: 10.1002/glia.23162] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/10/2017] [Accepted: 04/18/2017] [Indexed: 12/21/2022]
Abstract
Genetically caused neurological disorders of the central nervous system (CNS) are usually orphan diseases with poor or even fatal clinical outcome and few or no treatments that will improve longevity or at least quality of life. Neuroinflammation is common to many of these disorders, despite the fact that a plethora of distinct mutations and molecular changes underlie the disorders. In this article, data from corresponding animal models are analyzed to define the roles of innate and adaptive inflammation as modifiers and amplifiers of disease. We describe both common and distinct patterns of neuroinflammation in genetically mediated CNS disorders and discuss the contrasting mechanisms that lead to adverse versus neuroprotective effects. Moreover, we identify the juxtaparanode as a neuroanatomical compartment commonly associated with inflammatory cells and ongoing axonopathic changes, in models of diverse diseases. The identification of key immunological effector pathways that amplify neuropathic features should lead to realistic possibilities for translatable therapeutic interventions using existing immunomodulators. Moreover, evidence emerges that neuroinflammation is not only able to modify primary neural damage-related symptoms but also may lead to unexpected clinical outcomes such as neuropsychiatric syndromes.
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Affiliation(s)
- Janos Groh
- Department of Neurology, Developmental Neurobiology, University Hospital Würzburg, Josef-Schneider-Str. 11, Würzburg, D-97080, Germany
| | - Rudolf Martini
- Department of Neurology, Developmental Neurobiology, University Hospital Würzburg, Josef-Schneider-Str. 11, Würzburg, D-97080, Germany
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