1
|
Antipova V, Heimes D, Seidel K, Schulz J, Schmitt O, Holzmann C, Rolfs A, Bidmon HJ, González de San Román Martín E, Huesgen PF, Amunts K, Keiler J, Hammer N, Witt M, Wree A. Differently increased volumes of multiple brain areas in Npc1 mutant mice following various drug treatments. Front Neuroanat 2024; 18:1430790. [PMID: 39081805 PMCID: PMC11286580 DOI: 10.3389/fnana.2024.1430790] [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: 05/10/2024] [Accepted: 07/01/2024] [Indexed: 08/02/2024] Open
Abstract
Background Niemann-Pick disease type C1 (NPC1, MIM 257220) is a heritable lysosomal storage disease characterized by a progressive neurological degeneration that causes disability and premature death. A murine model of Npc1-/- displays a rapidly progressing form of Npc1 disease, which is characterized by weight loss, ataxia, and increased cholesterol storage. Npc1-/- mice receiving a combined therapy (COMBI) of miglustat (MIGLU), the neurosteroid allopregnanolone (ALLO) and the cyclic oligosaccharide 2-hydroxypropyl-β-cyclodextrin (HPßCD) showed prevention of Purkinje cell loss, improved motor function and reduced intracellular lipid storage. Although therapy of Npc1-/- mice with COMBI, MIGLU or HPßCD resulted in the prevention of body weight loss, reduced total brain weight was not positively influenced. Methods In order to evaluate alterations of different brain areas caused by pharmacotherapy, fresh volumes (volumes calculated from the volumes determined from paraffin embedded brain slices) of various brain structures in sham- and drug-treated wild type and mutant mice were measured using stereological methods. Results In the wild type mice, the volumes of investigated brain areas were not significantly altered by either therapy. Compared with the respective wild types, fresh volumes of specific brain areas, which were significantly reduced in sham-treated Npc1-/- mice, partly increased after the pharmacotherapies in all treatment strategies; most pronounced differences were found in the CA1 area of the hippocampus and in olfactory structures. Discussion Volumes of brain areas of Npc1-/- mice were not specifically changed in terms of functionality after administering COMBI, MIGLU, or HPßCD. Measurements of fresh volumes of brain areas in Npc1-/- mice could monitor region-specific changes and response to drug treatment that correlated, in part, with behavioral improvements in this mouse model.
Collapse
Affiliation(s)
- Veronica Antipova
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Graz, Austria
| | - Diana Heimes
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
- Department of Oral and Maxillofacial Surgery, University Medical Center Mainz, Mainz, Germany
| | - Katharina Seidel
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
- Klinik für Frauenheilkunde und Geburtshilfe, Dietrich-Bonhoeffer-Klinikum, Neubrandenburg, Germany
| | - Jennifer Schulz
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
| | - Oliver Schmitt
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
- Department of Anatomy, Medical School Hamburg, University of Applied Sciences and Medical University, Hamburg, Germany
| | - Carsten Holzmann
- Institute of Medical Genetics, Rostock University Medical Center, Rostock, Germany
- Centre of Transdisciplinary Neuroscience Rostock, Rostock, Germany
| | - Arndt Rolfs
- Medical Faculty, University of Rostock, Rostock, Germany
| | - Hans-Jürgen Bidmon
- Institute of Neurosciences and Medicine, Structural and Functional Organisation of the Brain (INM-1), Forschungszentrum Jülich, Jülich, Germany
- Central Institute of Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Jülich, Germany
| | | | - Pitter F. Huesgen
- Central Institute of Engineering, Electronics and Analytics, ZEA-3, Forschungszentrum Jülich, Jülich, Germany
- Institut für Biologie II, AG Funktional Proteomics, Freiburg, Germany
| | - Katrin Amunts
- Institute of Neurosciences and Medicine, Structural and Functional Organisation of the Brain (INM-1), Forschungszentrum Jülich, Jülich, Germany
- C. and O. Vogt Institute for Brain Research, University Hospital Düsseldorf, University Düsseldorf, Düsseldorf, Germany
| | - Jonas Keiler
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
| | - Niels Hammer
- Division of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Medical University of Graz, Graz, Austria
- Department of Orthopedic and Trauma Surgery, University of Leipzig, Leipzig, Germany
- Division of Biomechatronics, Fraunhofer Institute for Machine Tools and Forming Technology, Dresden, Germany
| | - Martin Witt
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
- Department of Anatomy, Technische Universität Dresden, Dresden, Germany
- Department of Anatomy, Institute of Biostructural Basics of Medical Sciences, Poznan Medical University, Poznan, Poland
| | - Andreas Wree
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
- Centre of Transdisciplinary Neuroscience Rostock, Rostock, Germany
| |
Collapse
|
2
|
Pfrieger FW. The Niemann-Pick type diseases – A synopsis of inborn errors in sphingolipid and cholesterol metabolism. Prog Lipid Res 2023; 90:101225. [PMID: 37003582 DOI: 10.1016/j.plipres.2023.101225] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/27/2023] [Accepted: 03/27/2023] [Indexed: 04/03/2023]
Abstract
Disturbances of lipid homeostasis in cells provoke human diseases. The elucidation of the underlying mechanisms and the development of efficient therapies represent formidable challenges for biomedical research. Exemplary cases are two rare, autosomal recessive, and ultimately fatal lysosomal diseases historically named "Niemann-Pick" honoring the physicians, whose pioneering observations led to their discovery. Acid sphingomyelinase deficiency (ASMD) and Niemann-Pick type C disease (NPCD) are caused by specific variants of the sphingomyelin phosphodiesterase 1 (SMPD1) and NPC intracellular cholesterol transporter 1 (NPC1) or NPC intracellular cholesterol transporter 2 (NPC2) genes that perturb homeostasis of two key membrane components, sphingomyelin and cholesterol, respectively. Patients with severe forms of these diseases present visceral and neurologic symptoms and succumb to premature death. This synopsis traces the tortuous discovery of the Niemann-Pick diseases, highlights important advances with respect to genetic culprits and cellular mechanisms, and exposes efforts to improve diagnosis and to explore new therapeutic approaches.
Collapse
|
3
|
Li JK, Rao YQ, Koh SK, Zhao P, Zhou L, Li J. Proteomic analysis of s-acylated proteins in human retinal pigment epithelial cells and the role of palmitoylation of Niemann-Pick type C1 protein in cholesterol transport. Front Aging Neurosci 2022; 14:965943. [PMID: 36262888 PMCID: PMC9576141 DOI: 10.3389/fnagi.2022.965943] [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: 06/10/2022] [Accepted: 08/26/2022] [Indexed: 11/13/2022] Open
Abstract
Palmitoylation is a dynamic process that regulates the activity of the modified proteins. Retinal pigment epithelial (RPE) cells play pivotal roles in the visual cycle and maintaining healthy photoreceptor cells. Dysfunctional RPE cells are often associated with degenerative retinal diseases. The aim of the study was to identify potentially palmitoylated proteins in human RPE cells. By using the detergent-resistant membrane, we found 312 potentially palmitoylated peptides which corresponded to 192 proteins in RPE cells, including 55 new candidate proteins which were not reported before. Gene enrichment analysis highlighted significant enrichment of palmitoylated proteins in cell-matrix adhesion, cell-cell recognition, protein cellular localization, and translation, among others. We further studied the effect of 3 potential palmitoylation sites (Cys 799, 900, and 816) of Niemann-Pick type C1 protein (NPC1) on cholesterol accumulation. We found that mutation of any single Cys alone had no significant effect on intracellular cholesterol accumulation while simultaneous mutation of Cys799 and 800 caused significant cholesterol accumulation in the late endosome. No further cholesterol accumulation was observed by adding another mutation at Cys 816. However, the mutation did not alter the cellular localization of the protein. Conclusion: PRE cells have an abundant number of palmitoylated proteins which are involved in cellular processes critical to visual function. The palmitoylation at Cys799 and 800 was needed for cholesterol export, but not the intracellular localization of NPC1.
Collapse
Affiliation(s)
- Jia Kai Li
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yu Qing Rao
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Siew Kwan Koh
- Singapore Eye Research Institute, Singapore, Singapore
| | - Peiquan Zhao
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Lei Zhou
- Singapore Eye Research Institute, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Research Program, Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
- *Correspondence: Lei Zhou,
| | - Jing Li
- Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Jing Li,
| |
Collapse
|
4
|
Yefimova MG, Béré E, Cantereau-Becq A, Meunier-Balandre AC, Merceron B, Burel A, Merienne K, Ravel C, Becq F, Bourmeyster N. Myelinosome Organelles in the Retina of R6/1 Huntington Disease (HD) Mice: Ubiquitous Distribution and Possible Role in Disease Spreading. Int J Mol Sci 2021; 22:ijms222312771. [PMID: 34884576 PMCID: PMC8657466 DOI: 10.3390/ijms222312771] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/08/2021] [Accepted: 11/22/2021] [Indexed: 12/12/2022] Open
Abstract
Visual deficit is one of the complications of Huntington disease (HD), a fatal neurological disorder caused by CAG trinucleotide expansions in the Huntingtin gene, leading to the production of mutant Huntingtin (mHTT) protein. Transgenic HD R6/1 mice expressing human HTT exon1 with 115 CAG repeats recapitulate major features of the human pathology and exhibit a degeneration of the retina. Our aim was to gain insight into the ultrastructure of the pathological HD R6/1 retina by electron microscopy (EM). We show that the HD R6/1 retina is enriched with unusual organelles myelinosomes, produced by retinal neurons and glia. Myelinosomes are present in all nuclear and plexiform layers, in the synaptic terminals of photoreceptors, in the processes of retinal neurons and glial cells, and in the subretinal space. In vitro study shows that myelinosomes secreted by human retinal glial Müller MIO-M1 cells transfected with EGFP-mHTT-exon1 carry EGFP-mHTT-exon1 protein, as revealed by immuno-EM and Western-blotting. Myelinosomes loaded with mHTT-exon1 are incorporated by naive neuronal/neuroblastoma SH-SY5Y cells. This results in the emergence of mHTT-exon1 in recipient cells. This process is blocked by membrane fusion inhibitor MDL 28170. Conclusion: Incorporation of myelinosomes carrying mHTT-exon1 in recipient cells may contribute to HD spreading in the retina. Exploring ocular fluids for myelinosome presence could bring an additional biomarker for HD diagnostics.
Collapse
Affiliation(s)
- Marina G. Yefimova
- Laboratoire Signalisation et Transports Ioniques Membranaires, Université de Poitiers/CNRS, 1 Rue Georges Bonnet, 86022 Poitiers, France; (A.C.-B.); (A.-C.M.-B.); (F.B.); (N.B.)
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, 44 Pr. Thorez, 194233 St. Petersburg, Russia
- Laboratoire de Biologie de la Reproduction-CECOS, Hopital SUD, 16 Bd de Bulgarie, CEDEX, 35000 Rennes, France;
- Correspondence:
| | - Emile Béré
- Plateforme IMAGE-UP, 1 Rue Georges Bonnet, 86022 Poitiers, France; (E.B.); (B.M.)
| | - Anne Cantereau-Becq
- Laboratoire Signalisation et Transports Ioniques Membranaires, Université de Poitiers/CNRS, 1 Rue Georges Bonnet, 86022 Poitiers, France; (A.C.-B.); (A.-C.M.-B.); (F.B.); (N.B.)
- Plateforme IMAGE-UP, 1 Rue Georges Bonnet, 86022 Poitiers, France; (E.B.); (B.M.)
| | - Annie-Claire Meunier-Balandre
- Laboratoire Signalisation et Transports Ioniques Membranaires, Université de Poitiers/CNRS, 1 Rue Georges Bonnet, 86022 Poitiers, France; (A.C.-B.); (A.-C.M.-B.); (F.B.); (N.B.)
| | - Bruno Merceron
- Plateforme IMAGE-UP, 1 Rue Georges Bonnet, 86022 Poitiers, France; (E.B.); (B.M.)
| | - Agnès Burel
- Plateforme Mric TEM, BIOSIT UMS 34 80, Université de Rennes 1, 2 Av. Pr. Léon Bernard, CEDEX, 35043 Rennes, France;
| | - Karine Merienne
- Laboratory of Cognitive and Adaptive Neurosciences (LNCA), University of Strasbourg, 67000 Strasbourg, France;
- CNRS UMR 7364, 67000 Strasbourg, France
| | - Célia Ravel
- Laboratoire de Biologie de la Reproduction-CECOS, Hopital SUD, 16 Bd de Bulgarie, CEDEX, 35000 Rennes, France;
| | - Frédéric Becq
- Laboratoire Signalisation et Transports Ioniques Membranaires, Université de Poitiers/CNRS, 1 Rue Georges Bonnet, 86022 Poitiers, France; (A.C.-B.); (A.-C.M.-B.); (F.B.); (N.B.)
| | - Nicolas Bourmeyster
- Laboratoire Signalisation et Transports Ioniques Membranaires, Université de Poitiers/CNRS, 1 Rue Georges Bonnet, 86022 Poitiers, France; (A.C.-B.); (A.-C.M.-B.); (F.B.); (N.B.)
- Service de Biochimie, CHU de Poitiers, 1, Rue de la Milétrie, 86021 Poitiers, France
| |
Collapse
|
5
|
Glial contribution to cyclodextrin-mediated reversal of cholesterol accumulation in murine NPC1-deficient neurons in vivo. Neurobiol Dis 2021; 158:105469. [PMID: 34364974 DOI: 10.1016/j.nbd.2021.105469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 07/17/2021] [Accepted: 08/02/2021] [Indexed: 12/11/2022] Open
Abstract
Niemann-Pick type C disease is a rare and fatal lysosomal storage disorder presenting severe neurovisceral symptoms. Disease-causing mutations in genes encoding either NPC1 or NPC2 protein provoke accumulation of cholesterol and other lipids in specific structures of the endosomal-lysosomal system and degeneration of specific cells, notably neurons in the central nervous system (CNS). 2-hydroxypropyl-beta-cyclodextrin (CD) emerged as potential therapeutic approach based on animal studies and clinical data, but the mechanism of action in neurons has remained unclear. To address this topic in vivo, we took advantage of the retina as highly accessible part of the CNS and intravitreal injections as mode of drug administration. Coupling CD to gold nanoparticles allowed us to trace its intracellular location. We report that CD enters the endosomal-lysosomal system of neurons in vivo and enables the release of lipid-laden lamellar inclusions, which are then removed from the extracellular space by specific types of glial cells. Our data suggest that CD induces a concerted action of neurons and glial cells to restore lipid homeostasis in the central nervous system.
Collapse
|
6
|
Holzmann C, Witt M, Rolfs A, Antipova V, Wree A. Gender-Specific Effects of Two Treatment Strategies in a Mouse Model of Niemann-Pick Disease Type C1. Int J Mol Sci 2021; 22:ijms22052539. [PMID: 33802605 PMCID: PMC7962008 DOI: 10.3390/ijms22052539] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 02/24/2021] [Accepted: 02/26/2021] [Indexed: 12/16/2022] Open
Abstract
In a mouse model of Niemann-Pick disease type C1 (NPC1), a combination therapy (COMBI) of miglustat (MIGLU), the neurosteroid allopregnanolone (ALLO) and the cyclic oligosaccharide 2-hydroxypropyl-β-cyclodextrin (HPßCD) has previously resulted in, among other things, significantly improved motor function. The present study was designed to compare the therapeutic effects of the COMBI therapy with that of MIGLU or HPßCD alone on body and brain weight and the behavior of NPC1−/− mice in a larger cohort, with special reference to gender differences. A total of 117 NPC1−/− and 123 NPC1+/+ mice underwent either COMBI, MIGLU only, HPßCD only, or vehicle treatment (Sham), or received no treatment at all (None). In male and female NPC1−/− mice, all treatments led to decreased loss of body weight and, partly, brain weight. Concerning motor coordination, as revealed by the accelerod test, male NPC1−/− mice benefited from COMBI treatment, whereas female mice benefited from COMBI, MIGLU, and HPßCD treatment. As seen in the open field test, the reduced locomotor activity of male and female NPC1−/− mice was not significantly ameliorated in either treatment group. Our results suggest that in NPC1−/− mice, each drug treatment scheme had a beneficial effect on at least some of the parameters evaluated compared with Sham-treated mice. Only in COMBI-treated male and female NPC+/+ mice were drug effects seen in reduced body and brain weights. Upon COMBI treatment, the increased dosage of drugs necessary for anesthesia in Sham-treated male and female NPC1−/− mice was almost completely reduced only in the female groups.
Collapse
Affiliation(s)
- Carsten Holzmann
- Institute of Medical Genetics, Rostock University Medical Center, D-18057 Rostock, Germany;
- Centre of Transdisciplinary Neuroscience Rostock, D-18147 Rostock, Germany;
| | - Martin Witt
- Centre of Transdisciplinary Neuroscience Rostock, D-18147 Rostock, Germany;
- Institute of Anatomy, Rostock University Medical Center, D-18057 Rostock, Germany;
| | - Arndt Rolfs
- Centogene AG, Rostock, Am Strande 7, 18055 Rostock, Germany;
- University of Rostock, 18055 Rostock, Germany
| | - Veronica Antipova
- Institute of Anatomy, Rostock University Medical Center, D-18057 Rostock, Germany;
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Macroscopic and Clinical Anatomy, Medical University of Graz, A-8010 Graz, Austria
| | - Andreas Wree
- Centre of Transdisciplinary Neuroscience Rostock, D-18147 Rostock, Germany;
- Institute of Anatomy, Rostock University Medical Center, D-18057 Rostock, Germany;
- Correspondence: ; Tel.: +49-381-494-8429
| |
Collapse
|
7
|
Abstract
Cholesterol is a quantitatively and biologically significant constituent of all mammalian cell membrane, including those that comprise the retina. Retinal cholesterol homeostasis entails the interplay between de novo synthesis, uptake, intraretinal sterol transport, metabolism, and efflux. Defects in these complex processes are associated with several congenital and age-related disorders of the visual system. Herein, we provide an overview of the following topics: (a) cholesterol synthesis in the neural retina; (b) lipoprotein uptake and intraretinal sterol transport in the neural retina and the retinal pigment epithelium (RPE); (c) cholesterol efflux from the neural retina and the RPE; and (d) biology and pathobiology of defects in sterol synthesis and sterol oxidation in the neural retina and the RPE. We focus, in particular, on studies involving animal models of monogenic disorders pertinent to the above topics, as well as in vitro models using biochemical, metabolic, and omic approaches. We also identify current knowledge gaps and opportunities in the field that beg further research in this topic area.
Collapse
Affiliation(s)
- Sriganesh Ramachandra Rao
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY, USA
| | - Steven J Fliesler
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York- University at Buffalo, Buffalo, NY, USA; Research Service, VA Western NY Healthcare System, Buffalo, NY, USA.
| |
Collapse
|
8
|
Retinal axonal degeneration in Niemann-Pick type C disease. J Neurol 2020; 267:2070-2082. [PMID: 32222928 PMCID: PMC7320959 DOI: 10.1007/s00415-020-09796-2] [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: 02/08/2020] [Revised: 03/13/2020] [Accepted: 03/14/2020] [Indexed: 11/21/2022]
Abstract
Objective Niemann–Pick disease type C1 (NPC1) is a rare autosomal-recessive lysosomal storage disorder presenting with a broad clinical spectrum ranging from a severe infantile-onset neurovisceral disorder to late-onset neurodegenerative disease. Optical coherence tomography (OCT) is established to detect retinal degeneration in vivo. We examined NPC1-patients (NPC1-P), clinically asymptomatic NPC1-mutation carriers (NPC1-MC), and healthy controls (HC) to (1) identify retinal degeneration in NPC1-disease and (2) to investigate possible subclinical retinal degeneration in NPC1-MC. Methods Fourteen NPC1-P, 17 NPC1-MC, and 31 age-matched HC were examined using spectral-domain OCT. Neurological examinations, clinical scales [modified Disability Rating Scale (mDRS); Scale for the Rating and Assessment of Ataxia (SARA); Spinocerebellar Ataxia Functional Index (SCAFI)], and video-oculography (VOG) were correlated with OCT data. Results Macular retinal nerve fiber layer and volumes of combined ganglion cell and inner plexiform layer were significantly lower in NPC1-P compared to HC [mRNFL (µm):0.13 ± 0.01 vs. 0.14 ± 0.02; p = 0.01; GCIPL (mm3):0.60 ± 0.05 vs. 0.62 ± 0.04; p = 0.04]. No significant differences were found in NPC1-MC in comparison to HC. In NPC1-P, the amplitude of upward vertical saccades showed positive associations with peripapillary RNFL (ρ = 0.645; p < 0.05), and thinned GCIP (ρ = 0.609; p < 0.05), but not in NPC1-MC. In NPC1-P correlations between combined outer plexiform layer and outer nuclear layer (OPONL) with mDRS (r = − 0.617; p < 0.05) and GCIP with SARA (r = − 0.622; p < 0.05) were observed. Furthermore, in NPC1-MC, motor scores were negatively associated with pRNFL (ρ = − 0.677; p < 0.01). Conclusions Using OCT, we showed retinal degeneration in NPC1-P and significant correlation between retinal neuroaxonal degeneration with clinical measurements. We observed a non-significant trend of retinal degeneration in NPC1-MC correlating with subclinical motor abnormalities. Based on these preliminary data, OCT may be an important marker of neurodegeneration in NPC1-disease after onset of clinical symptoms.
Collapse
|
9
|
Bräuer AU, Kuhla A, Holzmann C, Wree A, Witt M. Current Challenges in Understanding the Cellular and Molecular Mechanisms in Niemann-Pick Disease Type C1. Int J Mol Sci 2019; 20:ijms20184392. [PMID: 31500175 PMCID: PMC6771135 DOI: 10.3390/ijms20184392] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 02/06/2023] Open
Abstract
Rare diseases are a heterogeneous group of very different clinical syndromes. Their most common causes are defects in the hereditary material, and they can therefore be passed on to descendants. Rare diseases become manifest in almost all organs and often have a systemic expressivity, i.e., they affect several organs simultaneously. An effective causal therapy is often not available and can only be developed when the underlying causes of the disease are understood. In this review, we focus on Niemann–Pick disease type C1 (NPC1), which is a rare lipid-storage disorder. Lipids, in particular phospholipids, are a major component of the cell membrane and play important roles in cellular functions, such as extracellular receptor signaling, intracellular second messengers and cellular pressure regulation. An excessive storage of fats, as seen in NPC1, can cause permanent damage to cells and tissues in the brain and peripheral nervous system, but also in other parts of the body. Here, we summarize the impact of NPC1 pathology on several organ systems, as revealed in experimental animal models and humans, and give an overview of current available treatment options.
Collapse
Affiliation(s)
- Anja U Bräuer
- Research Group Anatomy, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, D-26129 Oldenburg, Germany.
- Research Center for Neurosensory Science, Carl von Ossietzky University Oldenburg, D-26129 Oldenburg, Germany.
| | - Angela Kuhla
- Institute for Experimental Surgery, Rostock University Medical Center, Schillingallee 69a, 18057 Rostock, Germany.
- Center of Transdisciplinary Neuroscience Rostock, D-18147 Rostock, Germany.
| | - Carsten Holzmann
- Center of Transdisciplinary Neuroscience Rostock, D-18147 Rostock, Germany.
- Institute of Medical Genetics, Rostock University Medical Center, D-18057 Rostock, Germany.
| | - Andreas Wree
- Center of Transdisciplinary Neuroscience Rostock, D-18147 Rostock, Germany.
- Institute of Anatomy, Rostock University Medical Center, D-18057 Rostock, Germany.
| | - Martin Witt
- Center of Transdisciplinary Neuroscience Rostock, D-18147 Rostock, Germany.
- Institute of Anatomy, Rostock University Medical Center, D-18057 Rostock, Germany.
| |
Collapse
|
10
|
Multimodal imaging including optical coherence tomography angiography in patients with type B Niemann-Pick disease. Int Ophthalmol 2019; 39:2545-2552. [PMID: 30977024 DOI: 10.1007/s10792-019-01102-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/01/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE To evaluate accumulation patterns of deposits in retinal layers of type B Niemann-Pick patients by multimodal imaging. METHODS Seven patients with type B Niemann-Pick disease were included in this study. All participants underwent a complete ophthalmologic evaluation, high-resolution digital colour imaging, spectral-domain optical coherence tomography, blue light fundus autofluorescence and optical coherence tomography angiography (OCTA). RESULTS We demonstrated different accumulation patterns in the retinal ganglion cell layer, the retinal nerve fibre layer and the subfoveolar region by multimodal imaging. Local retinal capillary nonflow areas in the superficial plexus, increased vascular tortuosity and deformed foveal avascular areas were shown in OCTA scans. CONCLUSION Multimodal imaging including OCTA is a useful technique for the identification of different types of accumulation patterns, diagnosis and follow-up of type B Niemann-Pick patients.
Collapse
|
11
|
Witt M, Thiemer R, Meyer A, Schmitt O, Wree A. Main Olfactory and Vomeronasal Epithelium Are Differently Affected in Niemann-Pick Disease Type C1. Int J Mol Sci 2018; 19:ijms19113563. [PMID: 30424529 PMCID: PMC6274921 DOI: 10.3390/ijms19113563] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/01/2018] [Accepted: 11/08/2018] [Indexed: 12/31/2022] Open
Abstract
INTRODUCTION Olfactory impairment is one of the earliest symptoms in neurodegenerative disorders that has also been documented in Niemann-Pick disease type C1 (NPC1). NPC1 is a very rare, neurovisceral lipid storage disorder, characterized by a deficiency of Npc1 gene function that leads to progressive neurodegeneration. Here, we compared the pathologic effect of defective Npc1 gene on the vomeronasal neuroepithelium (VNE) with that of the olfactory epithelium (OE) in an NPC1 mouse model. METHODS Proliferation in the VNE and OE was assessed by applying a bromodeoxyuridine (BrdU) protocol. We further compared the immunoreactivities of anti-olfactory marker protein (OMP), and the lysosomal marker cathepsin-D in both epithelia. To investigate if degenerative effects of both olfactory systems can be prevented or reversed, some animals were treated with a combination of miglustat/allopregnanolone/2-hydroxypropyl-cyclodextrin (HPβCD), or a monotherapy with HPβCD alone. RESULTS Using BrdU to label dividing cells of the VNE, we detected a proliferation increase of 215% ± 12% in Npc1-/- mice, and 270% ± 10% in combination- treated Npc1-/- animals. The monotherapy with HPβCD led to an increase of 261% ± 10.5% compared to sham-treated Npc1-/- mice. Similar to the OE, we assessed the high regenerative potential of vomeronasal progenitor cells. OMP reactivity in the VNE of Npc1-/- mice was not affected, in contrast to that observed in the OE. Concomitantly, cathepsin-D reactivity in the VNE was virtually absent. Conclusion: Vomeronasal receptor neurons are less susceptible against NPC1 pathology than olfactory receptor neurons. Compared to control mice, however, the VNE of Npc1-/- mice displays an increased neuroregenerative potential, indicating compensatory cell renewal.
Collapse
Affiliation(s)
- Martin Witt
- Department of Anatomy, University of Rostock, 18057 Rostock, Germany.
| | - René Thiemer
- Department of Anatomy, University of Rostock, 18057 Rostock, Germany.
| | - Anja Meyer
- Department of Anatomy, University of Rostock, 18057 Rostock, Germany.
| | - Oliver Schmitt
- Department of Anatomy, University of Rostock, 18057 Rostock, Germany.
| | - Andreas Wree
- Department of Anatomy, University of Rostock, 18057 Rostock, Germany.
| |
Collapse
|
12
|
Meyer A, Gläser A, Bräuer AU, Wree A, Strotmann J, Rolfs A, Witt M. Olfactory Performance as an Indicator for Protective Treatment Effects in an Animal Model of Neurodegeneration. Front Integr Neurosci 2018; 12:35. [PMID: 30154701 PMCID: PMC6102364 DOI: 10.3389/fnint.2018.00035] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 07/26/2018] [Indexed: 12/12/2022] Open
Abstract
Background: Neurodegenerative diseases are often accompanied by olfactory deficits. Here we use a rare neurovisceral lipid storage disorder, Niemann–Pick disease C1 (NPC1), to illustrate disease-specific dynamics of olfactory dysfunction and its reaction upon therapy. Previous findings in a transgenic mouse model (NPC1-/-) showed severe morphological and electrophysiological alterations of the olfactory epithelium (OE) and the olfactory bulb (OB) that ameliorated under therapy with combined 2-hydroxypropyl-ß-cyclodextrin (HPßCD)/allopregnanolone/miglustat or HPßCD alone. Methods: A buried pellet test was conducted to assess olfactory performance. qPCR for olfactory key markers and several olfactory receptors was applied to determine if their expression was changed under treatment conditions. In order to investigate the cell dynamics of the OB, we determined proliferative and apoptotic activities using a bromodeoxyuridine (BrdU) protocol and caspase-3 (cas-3) activity. Further, we performed immunohistochemistry and western blotting for microglia (Iba1), astroglia (GFAP) and tyrosine hydroxylase (TH). Results: The buried pellet test revealed a significant olfactory deterioration in NPC1-/- mice, which reverted to normal levels after treatment. At the OE level, mRNA for olfactory markers showed no changes; the mRNA level of classical olfactory receptor (ORs) was unaltered, that of unique ORs was reduced. In the OB of untreated NPC1-/- mice, BrdU and cas-3 data showed increased proliferation and apoptotic activity, respectively. At the protein level, Iba1 and GFAP in the OB indicated increased microgliosis and astrogliosis, which was prevented by treatment. Conclusion: Due to the unique plasticity especially of peripheral olfactory components the results show a successful treatment in NPC1 condition with respect to normalization of olfaction. Unchanged mRNA levels for olfactory marker protein and distinct olfactory receptors indicate no effects in the OE in NPC1-/- mice. Olfactory deficits are thus likely due to central deficits at the level of the OB. Further studies are needed to examine if olfactory performance can also be changed at a later onset and interrupted treatment of the disease. Taken together, our results demonstrate that olfactory testing in patients with NPC1 may be successfully used as a biomarker during the monitoring of the treatment.
Collapse
Affiliation(s)
- Anja Meyer
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
| | - Anne Gläser
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany.,Research Group Anatomy, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Anja U Bräuer
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany.,Research Group Anatomy, School of Medicine and Health Sciences, Carl von Ossietzky University Oldenburg, Oldenburg, Germany.,Research Center for Neurosensory Science, Carl von Ossietzky University Oldenburg, Oldenburg, Germany
| | - Andreas Wree
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
| | - Jörg Strotmann
- Institute of Physiology, University of Hohenheim, Stuttgart, Germany
| | - Arndt Rolfs
- Albrecht-Kossel-Institute for Neuroregeneration, Rostock University Medical Center, Rostock, Germany
| | - Martin Witt
- Institute of Anatomy, Rostock University Medical Center, Rostock, Germany
| |
Collapse
|
13
|
Ebner L, Gläser A, Bräuer A, Witt M, Wree A, Rolfs A, Frank M, Vollmar B, Kuhla A. Evaluation of Two Liver Treatment Strategies in a Mouse Model of Niemann-Pick-Disease Type C1. Int J Mol Sci 2018; 19:ijms19040972. [PMID: 29587349 PMCID: PMC5979582 DOI: 10.3390/ijms19040972] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 03/14/2018] [Accepted: 03/20/2018] [Indexed: 11/16/2022] Open
Abstract
Niemann–Pick-disease type C1 (NPC1) is an autosomal-recessive cholesterol-storage disorder. Besides other symptoms, NPC1 patients develop liver dysfunction and hepatosplenomegaly. The mechanisms of hepatomegaly and alterations of lipid metabolism-related genes in NPC1 disease are still poorly understood. Here, we used an NPC1 mouse model to study an additive hepatoprotective effect of a combination of 2-hydroxypropyl-β-cyclodextrin (HPβCD), miglustat and allopregnanolone (combination therapy) with the previously established monotherapy using HPβCD. We examined transgene effects as well as treatment effects on liver morphology and hepatic lipid metabolism, focusing on hepatic cholesterol transporter genes. Livers of Npc1−/− mice showed hepatic cholesterol sequestration with consecutive liver injury, an increase of lipogenetic gene expression, e.g., HMG-CoA, a decrease of lipolytic gene expression, e.g., pparα and acox1, and a decrease of lipid transporter gene expression, e.g., acat1, abca1 and fatp2. Both, combination therapy and monotherapy, led to a reduction of hepatic lipids and an amelioration of NPC1 liver disease symptoms. Monotherapy effects were related to pparα- and acox1-associated lipolysis/β-oxidation and to fatp2-induced fatty acid transport, whereas the combination therapy additionally increased the cholesterol transport via abca1 and apoE. However, HPβCD monotherapy additionally increased cholesterol synthesis as indicated by a marked increase of the HMG-CoA and srebp-2 mRNA expression, probably as a result of increased hepatocellular proliferation.
Collapse
Affiliation(s)
- Lynn Ebner
- Institute for Experimental Surgery, Rostock University Medical Center, Schillingallee 69a, 18057 Rostock, Germany.
| | - Anne Gläser
- Institute of Anatomy, Rostock University Medical Center, Gertrudenstraße 9, 18057 Rostock, Germany.
| | - Anja Bräuer
- Institute of Anatomy, Rostock University Medical Center, Gertrudenstraße 9, 18057 Rostock, Germany.
| | - Martin Witt
- Institute of Anatomy, Rostock University Medical Center, Gertrudenstraße 9, 18057 Rostock, Germany.
| | - Andreas Wree
- Institute of Anatomy, Rostock University Medical Center, Gertrudenstraße 9, 18057 Rostock, Germany.
| | - Arndt Rolfs
- Albrecht Kossel Institute for Neuroregeneration, Rostock University Medical Center, Gehlsheimer Straße 20, 18147 Rostock, Germany.
| | - Marcus Frank
- Medical Biology and Electron Microscopy Center, Rostock University Medical Center, 18057 Rostock, Germany.
| | - Brigitte Vollmar
- Institute for Experimental Surgery, Rostock University Medical Center, Schillingallee 69a, 18057 Rostock, Germany.
| | - Angela Kuhla
- Institute for Experimental Surgery, Rostock University Medical Center, Schillingallee 69a, 18057 Rostock, Germany.
| |
Collapse
|
14
|
Marshall CA, Watkins-Chow DE, Palladino G, Deutsch G, Chandran K, Pavan WJ, Erickson RP. In Niemann-Pick C1 mouse models, glial-only expression of the normal gene extends survival much further than do changes in genetic background or treatment with hydroxypropyl-beta-cyclodextrin. Gene 2017; 643:117-123. [PMID: 29223359 DOI: 10.1016/j.gene.2017.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 12/01/2017] [Accepted: 12/06/2017] [Indexed: 11/19/2022]
Abstract
The Npc1nmf164 allele of Npc1 provides a mouse model for Niemann-Pick disease type C1 (NPC1), a genetic disease known to have a widely variable phenotype. The transfer of the Npc1nmf164 mutation from the C57BL/6J inbred strain to the BALB/cJ inbred strain increased the mean lifespan from 117.8days to 153.1days, confirming that the severity of the NPC1 phenotype is strongly influenced by genetic background. The transfer of another Npc1 allele, Npc1nih, to this background also extended survival of the homozygotes indicating that the modifying effect of BALB/cJ is not limited to a single allele of Npc1. The increased longevity due to the BALB/cJ background did not map to a previously mapped modifier on chromosome 19, indicating the presence of additional genes impacting disease severity. The previously studied Glial Fibrillary Acidic Protein promoter-Npc1 cDNA transgene (GFAP-Npc1) which only expresses NPC1 in astrocytes further extended the lifespan of Npc1nmf164 homozygotes on a BALB/cJ background (up to 600days). Hydroxypropyl-β-cyclodextrin (HPβCD) treatment, not previously tested in the Npc1nmf164 mutant, extended life in the Npc1nmf164 homozygotes but not the transgenic, Npc1nmf164 mice on the BALB/cJ background. In all cases, lack of weight gain and early cerebellar symptoms of loss of motor control were found. At termination, the one mouse sacrificed for histological studies showed severe, diffuse pulmonary alveolar proteinosis suggesting that pulmonary abnormalities in NPC1 mouse models are not unique to the Npc1nih allele.
Collapse
Affiliation(s)
- Craig A Marshall
- Department of Pediatrics, University of Arizona College of Medicine, Tucson, AZ 85724-5073, United States
| | - Dawn E Watkins-Chow
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Giampiero Palladino
- Department of Pediatrics, University of Arizona College of Medicine, Tucson, AZ 85724-5073, United States
| | - Gail Deutsch
- Department of Pathology, Seattle Children's Hospital, Seattle, WA, United States
| | - Keshav Chandran
- Department of Pediatrics, University of Arizona College of Medicine, Tucson, AZ 85724-5073, United States
| | - William J Pavan
- National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Robert P Erickson
- Department of Pediatrics, University of Arizona College of Medicine, Tucson, AZ 85724-5073, United States.
| |
Collapse
|
15
|
Hindle SJ, Hebbar S, Schwudke D, Elliott CJH, Sweeney ST. A saposin deficiency model in Drosophila: Lysosomal storage, progressive neurodegeneration and sensory physiological decline. Neurobiol Dis 2016; 98:77-87. [PMID: 27913291 PMCID: PMC5319729 DOI: 10.1016/j.nbd.2016.11.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 11/10/2016] [Accepted: 11/25/2016] [Indexed: 02/06/2023] Open
Abstract
Saposin deficiency is a childhood neurodegenerative lysosomal storage disorder (LSD) that can cause premature death within three months of life. Saposins are activator proteins that promote the function of lysosomal hydrolases that mediate the degradation of sphingolipids. There are four saposin proteins in humans, which are encoded by the prosaposin gene. Mutations causing an absence or impaired function of individual saposins or the whole prosaposin gene lead to distinct LSDs due to the storage of different classes of sphingolipids. The pathological events leading to neuronal dysfunction induced by lysosomal storage of sphingolipids are as yet poorly defined. We have generated and characterised a Drosophila model of saposin deficiency that shows striking similarities to the human diseases. Drosophila saposin-related (dSap-r) mutants show a reduced longevity, progressive neurodegeneration, lysosomal storage, dramatic swelling of neuronal soma, perturbations in sphingolipid catabolism, and sensory physiological deterioration. Our data suggests a genetic interaction with a calcium exchanger (Calx) pointing to a possible calcium homeostasis deficit in dSap-r mutants. Together these findings support the use of dSap-r mutants in advancing our understanding of the cellular pathology implicated in saposin deficiency and related LSDs. Drosophila model of PSD recapitulates neurodegenerative phenotype of human PSD. Preferential degeneration of sensory regions correlates with loss of sensory function. Sphingosine levels rise with age with an imbalance in sphingosine/ceramide ratios. Genetic interaction with the Na +/Ca + exchanger points to a calcium regulation deficit.
Collapse
Affiliation(s)
| | - Sarita Hebbar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India
| | - Dominik Schwudke
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, Karnataka 560065, India
| | | | - Sean T Sweeney
- Department of Biology, University of York, York YO10 5DD, UK.
| |
Collapse
|
16
|
Adebali O, Reznik AO, Ory DS, Zhulin IB. Establishing the precise evolutionary history of a gene improves prediction of disease-causing missense mutations. Genet Med 2016; 18:1029-36. [PMID: 26890452 PMCID: PMC4990510 DOI: 10.1038/gim.2015.208] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/09/2015] [Indexed: 11/29/2022] Open
Abstract
Purpose: Predicting the phenotypic effects of mutations has become an important application in clinical genetic diagnostics. Computational tools evaluate the behavior of the variant over evolutionary time and assume that variations seen during the course of evolution are probably benign in humans. However, current tools do not take into account orthologous/paralogous relationships. Paralogs have dramatically different roles in Mendelian diseases. For example, whereas inactivating mutations in the NPC1 gene cause the neurodegenerative disorder Niemann-Pick C, inactivating mutations in its paralog NPC1L1 are not disease-causing and, moreover, are implicated in protection from coronary heart disease. Methods: We identified major events in NPC1 evolution and revealed and compared orthologs and paralogs of the human NPC1 gene through phylogenetic and protein sequence analyses. We predicted whether an amino acid substitution affects protein function by reducing the organism’s fitness. Results: Removing the paralogs and distant homologs improved the overall performance of categorizing disease-causing and benign amino acid substitutions. Conclusion: The results show that a thorough evolutionary analysis followed by identification of orthologs improves the accuracy in predicting disease-causing missense mutations. We anticipate that this approach will be used as a reference in the interpretation of variants in other genetic diseases as well. Genet Med18 10, 1029–1036.
Collapse
Affiliation(s)
- Ogun Adebali
- Graduate School of Genome Science and Technology, University of Tennessee-Oak Ridge National Laboratory, Knoxville, Tennessee, USA.,Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.,Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| | - Alexander O Reznik
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA.,Present address: Center for Bioinformatics, Pavlov First Saint Petersburg State Medical University, Saint Petersburg, Russia
| | - Daniel S Ory
- Diabetes Cardiovascular Disease Center, Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Igor B Zhulin
- Graduate School of Genome Science and Technology, University of Tennessee-Oak Ridge National Laboratory, Knoxville, Tennessee, USA.,Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA.,Department of Microbiology, University of Tennessee, Knoxville, Tennessee, USA
| |
Collapse
|
17
|
Palladino G, Loizzo S, Fortuna A, Canterini S, Palombi F, Erickson RP, Mangia F, Fiorenza MT. Visual evoked potentials of Niemann-Pick type C1 mice reveal an impairment of the visual pathway that is rescued by 2-hydroxypropyl-ß-cyclodextrin. Orphanet J Rare Dis 2015; 10:133. [PMID: 26458950 PMCID: PMC4603821 DOI: 10.1186/s13023-015-0348-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Accepted: 09/27/2015] [Indexed: 12/21/2022] Open
Abstract
Background The lysosomal storage disorder, Niemann Pick type C1 (NPC1), presents a variable phenotype including neurovisceral and neurological symptoms. 2-Hydroxypropyl-ß-cyclodextrin (HPßCD)-based therapies are presently the most promising route of intervention. While severe cerebellar dysfunction remains the main disabling feature of NPC1, sensory functions including auditory and olfactory ones are also affected. Morphological and functional anomalies of Npc1−/− mouse retina have also been observed, although the functional integrity of the visual pathway from retina to visual cortex is still unsettled. We have addressed this issue by characterizing the visual evoked potential (VEP) response of Npc1−/− mice and determining if/how HPßCD administration influences the VEPs of both Npc1−/− and Npc1+/+ mice. Methods VEP elicited by a brief visual stimulus were recorded from the scalp overlying the visual cortex of adult (PN, postnatal days 60, 75, 85 and 100) Npc1+/+ and Npc1−/− mice that had received repeated injections of either HPßCD or plain vehicle. The first injection was given at PN4 and was followed by a second one at PN7 and thereafter by weekly injections up to PN49. Cholesterol accumulation and myelin loss were finally assessed by filipin staining and myelin basic protein immunohistochemistry, respectively. Results and discussion We have found that the transmission of visual signals from retina to visual cortex is negatively influenced by the loss of Npc1 function. In fact, the VEP response of Npc1−/− mice displayed a highly significant increase in the latency compared to that of Npc1+/+ mice. HPßCD administration fully rescued this defect and counteracted the cholesterol accumulation in retinal ganglion cells and dorsal lateral geniculate nucleus neurons, as well as the myelin loss in optic nerve fibers and axons projecting to the visual cortex observed in of Npc1−/− mice. By contrast, HPßCD administration had no effect on the VEP response of Npc1+/+ mice, further strengthening the treatment efficacy. Conclusions This study pinpoints the analysis of VEP response as a potentially accurate and non-invasive approach to assess neural activity and visual information processing in NPC1 patients, as well as for monitoring the progression of the disease and assessing the efficacy of potential therapies. Electronic supplementary material The online version of this article (doi:10.1186/s13023-015-0348-0) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Giampiero Palladino
- Department of Psychology, Section of Neuroscience and "Daniel Bovet" Neurobiology Research Center, Sapienza University of Rome, 00185, Rome, Italy
| | - Stefano Loizzo
- Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, via Regina Elena 299, 00161, Rome, Italy
| | - Andrea Fortuna
- Department of Therapeutic Research and Medicines Evaluation, Istituto Superiore di Sanità, via Regina Elena 299, 00161, Rome, Italy
| | - Sonia Canterini
- Department of Psychology, Section of Neuroscience and "Daniel Bovet" Neurobiology Research Center, Sapienza University of Rome, 00185, Rome, Italy
| | - Fioretta Palombi
- Department of Anatomy, Histology, Forensic Medicine and Orthopedics, Unit of Histology and Medical Embryology, Sapienza University of Rome, 00161, Rome, Italy
| | - Robert P Erickson
- Department of Pediatrics, University of Arizona, Tucson, AZ, 85724-5073, USA
| | - Franco Mangia
- Department of Psychology, Section of Neuroscience and "Daniel Bovet" Neurobiology Research Center, Sapienza University of Rome, 00185, Rome, Italy
| | - Maria Teresa Fiorenza
- Department of Psychology, Section of Neuroscience and "Daniel Bovet" Neurobiology Research Center, Sapienza University of Rome, 00185, Rome, Italy.
| |
Collapse
|