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LeVine SM. Examining the Role of a Functional Deficiency of Iron in Lysosomal Storage Disorders with Translational Relevance to Alzheimer's Disease. Cells 2023; 12:2641. [PMID: 37998376 PMCID: PMC10670892 DOI: 10.3390/cells12222641] [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: 10/25/2023] [Revised: 11/09/2023] [Accepted: 11/13/2023] [Indexed: 11/25/2023] Open
Abstract
The recently presented Azalea Hypothesis for Alzheimer's disease asserts that iron becomes sequestered, leading to a functional iron deficiency that contributes to neurodegeneration. Iron sequestration can occur by iron being bound to protein aggregates, such as amyloid β and tau, iron-rich structures not undergoing recycling (e.g., due to disrupted ferritinophagy and impaired mitophagy), and diminished delivery of iron from the lysosome to the cytosol. Reduced iron availability for biochemical reactions causes cells to respond to acquire additional iron, resulting in an elevation in the total iron level within affected brain regions. As the amount of unavailable iron increases, the level of available iron decreases until eventually it is unable to meet cellular demands, which leads to a functional iron deficiency. Normally, the lysosome plays an integral role in cellular iron homeostasis by facilitating both the delivery of iron to the cytosol (e.g., after endocytosis of the iron-transferrin-transferrin receptor complex) and the cellular recycling of iron. During a lysosomal storage disorder, an enzyme deficiency causes undigested substrates to accumulate, causing a sequelae of pathogenic events that may include cellular iron dyshomeostasis. Thus, a functional deficiency of iron may be a pathogenic mechanism occurring within several lysosomal storage diseases and Alzheimer's disease.
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Affiliation(s)
- Steven M LeVine
- Department of Cell Biology and Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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Stroobants S, Damme M, Van der Jeugd A, Vermaercke B, Andersson C, Fogh J, Saftig P, Blanz J, D'Hooge R. Long-term enzyme replacement therapy improves neurocognitive functioning and hippocampal synaptic plasticity in immune-tolerant alpha-mannosidosis mice. Neurobiol Dis 2017; 106:255-268. [PMID: 28720484 DOI: 10.1016/j.nbd.2017.07.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/14/2017] [Indexed: 01/22/2023] Open
Abstract
Alpha-mannosidosis is a glycoproteinosis caused by deficiency of lysosomal acid alpha-mannosidase (LAMAN), which markedly affects neurons of the central nervous system (CNS), and causes pathognomonic intellectual dysfunction in the clinical condition. Cognitive improvement consequently remains a major therapeutic objective in research on this devastating genetic error. Immune-tolerant LAMAN knockout mice were developed to evaluate the effects of enzyme replacement therapy (ERT) by prolonged administration of recombinant human enzyme. Biochemical evidence suggested that hippocampus may be one of the brain structures that benefits most from long-term ERT. In the present functional study, ERT was initiated in 2-month-old immune-tolerant alpha-mannosidosis mice and continued for 9months. During the course of treatment, mice were trained in the Morris water maze task to assess spatial-cognitive performance, which was related to synaptic plasticity recordings and hippocampal histopathology. Long-term ERT reduced primary substrate storage and neuroinflammation in hippocampus, and improved spatial learning after mid-term (10weeks+) and long-term (30weeks+) treatment. Long-term treatment substantially improved the spatial-cognitive abilities of alpha-mannosidosis mice, whereas the effects of mid-term treatment were more modest. Detailed analyses of spatial memory and spatial-cognitive performance indicated that even prolonged ERT did not restore higher cognitive abilities to the level of healthy mice. However, it did demonstrate marked therapeutic effects that coincided with increased synaptic connectivity, reflected by improvements in hippocampal CA3-CA1 long-term potentiation (LTP), expression of postsynaptic marker PSD-95 as well as postsynaptic density morphology. These experiments indicate that long-term ERT may hold promise, not only for the somatic defects of alpha-mannosidosis, but also to alleviate cognitive impairments of the disorder.
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Affiliation(s)
- Stijn Stroobants
- Laboratory of Biological Psychology, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium.
| | - Markus Damme
- Institute of Biochemistry, University of Kiel, Olshausenstrasse 40, 24098 Kiel, Germany.
| | - Ann Van der Jeugd
- Laboratory of Biological Psychology, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium.
| | - Ben Vermaercke
- Laboratory of Biological Psychology, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium.
| | | | - Jens Fogh
- Zymenex A/S, Roskildevej 12C, 3400 Hillerød, Denmark.
| | - Paul Saftig
- Institute of Biochemistry, University of Kiel, Olshausenstrasse 40, 24098 Kiel, Germany.
| | - Judith Blanz
- Institute of Biochemistry, University of Kiel, Olshausenstrasse 40, 24098 Kiel, Germany.
| | - Rudi D'Hooge
- Laboratory of Biological Psychology, KU Leuven, Tiensestraat 102, 3000 Leuven, Belgium.
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Borgwardt L, Thuesen AM, Olsen KJ, Fogh J, Dali CI, Lund AM. Cognitive profile and activities of daily living: 35 patients with alpha-mannosidosis. J Inherit Metab Dis 2015; 38:1119-27. [PMID: 26016802 DOI: 10.1007/s10545-015-9862-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 05/05/2015] [Accepted: 05/11/2015] [Indexed: 10/23/2022]
Abstract
BACKGROUND Alpha-mannosidosis (OMIM 248500) (AM) is a rare lysosomal storage disease caused by a deficiency of the alpha-mannosidase enzyme. The typical signs consist of hearing impairment, intellectual disabilities, coarse facial features and motor function disturbances. We report on the cognitive function and activities of daily living in patients with AM. METHODS Thirty five AM patients, age 6-35 years, were included in the study. As a cognitive function test, we used the Leiter international performance scale-revised (Leiter-R), which consists of two batteries: the visual function and reasoning battery and the memory and attention battery, the latter including a memory screening. Additional two questionnaires, The Childhood Health Assessment Questionnaire (CHAQ) and EQ-5D-5 L, were filled out. RESULTS We found IQ in the range of 30-81 in our cohort. The total equivalent age (mental age) was significantly reduced, between 3-9 years old for the visual function and reasoning battery, between 2.3-10.2 years for the memory screening. Data suggested a specific developmental profile for AM with a positive intellectual development until the chronological age 10-12 years, followed by a static or slightly increasing intellectual level. All patients were to varying degrees socially and practically dependent and unable to take care of themselves in daily life. CONCLUSIONS Intellectual disability is a consistent finding in patients with alpha-mannosidosis but with extensive variation. We assess that this group of patients has, despite their intellectual disabilities, a potential for continuous cognitive development, especially during childhood and early teenage years. This should be included and supported in the individual educational planning.
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Affiliation(s)
- L Borgwardt
- Department of Clinical Genetics, Centre for Inherited Metabolic Diseases, Copenhagen University Hospital, Rigshospitalet, 9 Blegdamsvej, 2100, Copenhagen, Denmark.
| | | | | | - J Fogh
- Zymenex A/S (Chiesi Group), Hilleroed, Denmark
| | - C I Dali
- Department of Clinical Genetics, Centre for Inherited Metabolic Diseases, Copenhagen University Hospital, Rigshospitalet, 9 Blegdamsvej, 2100, Copenhagen, Denmark
| | - A M Lund
- Department of Clinical Genetics, Centre for Inherited Metabolic Diseases, Copenhagen University Hospital, Rigshospitalet, 9 Blegdamsvej, 2100, Copenhagen, Denmark
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Goddyn H, Callaerts-Vegh Z, D'Hooge R. Functional Dissociation of Group III Metabotropic Glutamate Receptors Revealed by Direct Comparison between the Behavioral Profiles of Knockout Mouse Lines. Int J Neuropsychopharmacol 2015; 18:pyv053. [PMID: 25999589 PMCID: PMC4756720 DOI: 10.1093/ijnp/pyv053] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 05/07/2015] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Group III metabotropic glutamate receptors (mGlu4, mGlu7, mGlu8) display differential brain distribution, which suggests different behavioral functions. However, comparison across the available animal studies remains methodologically hazardous and controversial. The present report directly compares knockouts for each group III receptor subtype using a single behavioral test battery and multivariate analysis. METHODS The behavioral phenotypes of C57BL/6J mice lacking mGlu4, mGlu7, or mGlu8 and their respective littermates were examined using a multimetric test battery, which included elements of neuromotor performance, exploratory behavior, and learning and memory. Multivariate statistical methods were used to identify subtype-specific behavioral profiles and variables that distinguished between these mouse lines. RESULTS It generally appears that mGlu7 plays a significant role in hippocampus-dependent spatial learning and in some fear-related behaviors, whereas mGlu4 is most clearly involved in startle and motivational processes. Excepting its influence on body weight, the effect of mGlu8 deletion on behavior appears more subtle than that of the other group III receptors. These receptors have been proposed as potential drug targets for a variety of psychopathological conditions. CONCLUSION On the basis of these controlled comparisons, we presently conclude that the different group III receptors indeed have quite distinct behavioral functions.
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Affiliation(s)
- Hannelore Goddyn
- KU Leuven, Laboratory of Biological Psychology, Leuven, Belgium (Drs Goddyn, Callaerts-Vegh, and D'Hooge)
| | - Zsuzsanna Callaerts-Vegh
- KU Leuven, Laboratory of Biological Psychology, Leuven, Belgium (Drs Goddyn, Callaerts-Vegh, and D'Hooge)
| | - Rudi D'Hooge
- KU Leuven, Laboratory of Biological Psychology, Leuven, Belgium (Drs Goddyn, Callaerts-Vegh, and D'Hooge).
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Robinson L, Plano A, Cobb S, Riedel G. Long-term home cage activity scans reveal lowered exploratory behaviour in symptomatic female Rett mice. Behav Brain Res 2013; 250:148-56. [PMID: 23643691 PMCID: PMC3885800 DOI: 10.1016/j.bbr.2013.04.041] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Revised: 04/22/2013] [Accepted: 04/25/2013] [Indexed: 01/25/2023]
Abstract
Numerous experimental models have been developed to reiterate endophenotypes of Rett syndrome, a neurodevelopmental disorder with a multitude of motor, cognitive and vegetative symptoms. Here, female Mecp2(Stop) mice [1] were characterised at mild symptomatic conditions in tests for anxiety (open field, elevated plus maze) and home cage observation systems for food intake, locomotor activity and circadian rhythms. Aged 8-9 months, Mecp2(Stop) mice presented with heightened body weight, lower overall activity in the open field, but no anxiety phenotype. Although home cage activity scans conducted in two different observation systems, PhenoMaster and PhenoTyper, confirmed normal circadian activity, they revealed severely compromised habituation to a novel environment in all parameters registered including those derived from a non-linear decay model such as initial exploration maximum, decay half-life of activity and span, as well as plateau. Furthermore, overall activity was significantly reduced in nocturnal periods due to reductions in both fast ambulatory movements, but also a slow lingering. In contrast, light-period activity profiles during which the amount of sleep was highest remained normal in Mecp2(Stop) mice. These data confirm the slow and progressive development of Rett-like symptoms in female Mecp2(Stop) mice resulting in a prominent reduction of overall locomotor activity, while circadian rhythms are maintained. Alterations in the time-course of habituation may indicate deficiencies in cognitive processing.
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Affiliation(s)
- Lianne Robinson
- School of Medical Science, College of Life Science and Medicine, University of Aberdeen, Aberdeen, AB25 2ZD Scotland, UK
| | - Andrea Plano
- School of Medical Science, College of Life Science and Medicine, University of Aberdeen, Aberdeen, AB25 2ZD Scotland, UK
| | - Stuart Cobb
- Institute of Neuroscience and Psychology, University of Glasgow, G12 8QQ, UK
| | - Gernot Riedel
- School of Medical Science, College of Life Science and Medicine, University of Aberdeen, Aberdeen, AB25 2ZD Scotland, UK
- Corresponding author at: School of Medical Sciences, College of Life Science and Medicine, Institute of Medical Science, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK. Tel.: +44 01224 437377; fax: +44 01224 437465.
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Cerebellar alterations and gait defects as therapeutic outcome measures for enzyme replacement therapy in α-mannosidosis. J Neuropathol Exp Neurol 2011; 70:83-94. [PMID: 21157375 DOI: 10.1097/nen.0b013e31820428fa] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
α-Mannosidosis is a rare lysosomal storage disease with accumulation of undegraded mannosyl-linked oligosaccharides in cells throughout the body, most notably in the CNS. This leads to a broad spectrum of neurological manifestations, including progressive intellectual impairment, disturbed motor functions, and cerebellar atrophy. To develop therapeutic outcome measures for enzyme replacement therapy that could be used for human patients, a gene knockout model of α-mannosidosis in mice was analyzed for CNS pathology and motor deficits. In the cerebellar molecular layer, α-mannosidosis mice display clusters of activated Bergman glia, infiltration of phagocytic macrophages, and accumulation of free cholesterol and gangliosides (GM1), notably in regions lacking Purkinje cells. α-Mannosidosis brain lysates also displayed increased expression of Lamp1 and hyperglycosylation of the cholesterol binding protein NPC2. Detailed assessment of motor function revealed age-dependent gait defects in the mice that resemble the disturbed motor function in human patients. Short-term enzyme replacement therapy partially reversed the observed cerebellar pathology with fewer activated macrophages and astrocytes but unchanged levels of hyperglycosylated NPC2, gangliosides, and cholesterol. The present study demonstrates cerebellar alterations in α-mannosidosis mice that relate to the motor deficits and pathological changes seen in human patients and can be used as therapeutic outcome measures.
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Kollmann K, Damme M, Deuschl F, Kahle J, D’Hooge R, Lüllmann-Rauch R, Lübke T. Molecular characterization and gene disruption of mouse lysosomal putative serine carboxypeptidase 1. FEBS J 2009; 276:1356-69. [DOI: 10.1111/j.1742-4658.2009.06877.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Blanz J, Stroobants S, Lüllmann-Rauch R, Morelle W, Lüdemann M, D'Hooge R, Reuterwall H, Michalski JC, Fogh J, Andersson C, Saftig P. Reversal of peripheral and central neural storage and ataxia after recombinant enzyme replacement therapy in α-mannosidosis mice. Hum Mol Genet 2008; 17:3437-45. [DOI: 10.1093/hmg/ddn237] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Absence of functional peroxisomes from mouse CNS causes dysmyelination and axon degeneration. J Neurosci 2008; 28:4015-27. [PMID: 18400901 DOI: 10.1523/jneurosci.4968-07.2008] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Peroxisomal metabolism is essential for normal brain development both in men and in mice. Using conditional knock-out mice, we recently showed that peroxisome deficiency in liver has a severe and persistent impact on the formation of cortex and cerebellum, whereas absence of functional peroxisomes from the CNS only causes developmental delays without obvious alteration of brain architecture. We now report that a substantial fraction of the latter Nes-Pex5 knock-out mice survive into adulthood but develop progressive motoric and coordination problems, impaired exploration, and a deficit in cognition and die before the age of 6 months. Histopathologically, both the white and gray matter of the CNS displayed a region-specific accumulation of neutral lipids, astrogliosis and microgliosis, upregulation of catalase, and scattered cell death. Nes-Pex5 knock-out mice featured a dramatic reduction of myelin staining in corpus callosum, whereas cerebellum and other white matter tracts were less affected or unchanged. This was accompanied by a depletion of alkenylphospholipids in myelin and differentially reduced immunoreactivity of myelin proteins. EM analysis revealed that myelin wrappings around axons did still form, but they showed a reduction in thickness relative to axon diameters. Remarkably, multifocal axonal damage occurred in the corpus callosum. Thereby, debris accumulated between axolemma and inner myelin surface and axons collapsed, although myelin sheaths remained present. These anomalies of myelinated axons were already present in juvenile mice but aggravated in adulthood. Together, loss of CNS peroxisomal metabolism both affects myelin sheaths and axonal integrity possibly via independent pathways.
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