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Bannykh KS, Fuentes-Fayos AC, Linesch PW, Breunig JJ, Bannykh SI. Laminin Beta 2 Is Localized at the Sites of Blood-Brain Barrier and Its Disruption Is Associated With Increased Vascular Permeability, Histochemical, and Transcriptomic Study. J Histochem Cytochem 2024:221554241281896. [PMID: 39340425 DOI: 10.1369/00221554241281896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/30/2024] Open
Abstract
Heterotrimeric extracellular matrix proteins laminins are mostly deposited at basal membranes and are important in repair and neoplasia. Here, we localize laminin beta 2 (LAMB2) at the sites of blood-brain barrier (BBB). Microvasculature (MV) of normal brain is endowed with complete LAMB2 coverage. In contrast, its cognate protein laminin beta 1 (LAMB1) is absent in MV of normal brain but emerges at the sprouting tip of a growing vessels. Similarly, vascular proliferation in high-grade gliomas (HGG) is accompanied by marked overexpression of LAMB1, whereas LAMB2 shows deficient deposition. We find that many brain pathologies with presence of post-gadolinium enhancement (PGE) on magnetic resonance imaging (MRI) show disruption of LAMB2 vascular ensheathment. Inhibition of vascular endothelial growth factor signaling in HGG blocks angiogenesis, suppresses PGE in HGG, prevents expression of LAMB1, and restores LAMB2 vascular coverage. Analysis of single-cell RNA sequencing (scRNA-seq) databases shows that in quiescent brain LAMB2 is predominantly expressed by BBB-associated pericytes (PCs) and endothelial cells (ECs), whereas neither cell types produce LAMB1. In contrast, in HGG, both LAMB1 and 2 are overexpressed by endothelial precursor cells, a phenotypically unique immature group, specific to proliferating hyperplastic MV.
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Affiliation(s)
- Katherine S Bannykh
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Antonio C Fuentes-Fayos
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California
| | - Paul W Linesch
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
| | - Joshua J Breunig
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, California
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Center for Neural Sciences in Medicine, Cedars-Sinai Medical Center, Los Angeles, California
- Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Serguei I Bannykh
- Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Medical Center, Los Angeles, California
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2
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Yurchenco PD, Kulczyk AW. Polymerizing laminins in development, health, and disease. J Biol Chem 2024; 300:107429. [PMID: 38825010 PMCID: PMC11260871 DOI: 10.1016/j.jbc.2024.107429] [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: 01/11/2024] [Revised: 05/12/2024] [Accepted: 05/26/2024] [Indexed: 06/04/2024] Open
Abstract
Polymerizing laminins are multi-domain basement membrane (BM) glycoproteins that self-assemble into cell-anchored planar lattices to establish the initial BM scaffold. Nidogens, collagen-IV and proteoglycans then bind to the scaffold at different domain loci to create a mature BM. The LN domains of adjacent laminins bind to each other to form a polymer node, while the LG domains attach to cytoskeletal-anchoring integrins and dystroglycan, as well as to sulfatides and heparan sulfates. The polymer node, the repeating unit of the polymer scaffold, is organized into a near-symmetrical triskelion. The structure, recently solved by cryo-electron microscopy in combination with AlphaFold2 modeling and biochemical studies, reveals how the LN surface residues interact with each other and how mutations cause failures of self-assembly in an emerging group of diseases, the LN-lamininopathies, that include LAMA2-related dystrophy and Pierson syndrome.
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Affiliation(s)
- Peter D Yurchenco
- Department of Pathology & Laboratory Medicine, Robert Wood Johnson Medical School, Rutgers University, Piscataway, New Jersey, USA.
| | - Arkadiusz W Kulczyk
- Department of Biochemistry and Microbiology, Institute for Quantitative Biomedicine, Rutgers University, Piscataway, New Jersey, USA
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3
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Boyer O, Mollet G, Dorval G. [Neurological disorders and hereditary podocytopathies: Some fascinating pathophysiological overlaps]. Med Sci (Paris) 2023; 39:246-252. [PMID: 36943121 DOI: 10.1051/medsci/2023029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023] Open
Abstract
Genetic studies of hereditary steroid resistant nephrotic syndrome (SRNS) have identified more than 60 genes involved in the development of single-gene, isolated or syndromic forms of hereditary podocytoapthies. Sometimes, syndromic SRNS is associated with neurological disorders. Over the past decades, various studies have established links between the podocyte, an epithelial glomerular cell involved in the renal filtration barrier, and neuronal cells, both morphologically (slit diaphragm and synapse) and functionally (signaling platforms). Variants of genes encoding proteins expressed in different compartments of the podocyte and neurons are responsible for phenotypes associating renal lesions with proteinuria to central and/or peripheral neurological disorders. In this review, we aim to focus on genetic syndromes associating proteinuria and neurological disease and to present the latest advances in the description of these neuro-renal disorders.
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Affiliation(s)
- Olivia Boyer
- Service de néphrologie pédiatrique, AP-HP, Centre de référence de maladies rénales rares de l'enfant et de l'adulte (MARHEA), hôpital Necker - Enfants Malades, Paris, France - Université Paris Cité, institut Imagine, laboratoire des maladies rénales héréditaires, Inserm UMR1163, Paris, France
| | - Géraldine Mollet
- Université Paris Cité, institut Imagine, laboratoire des maladies rénales héréditaires, Inserm UMR1163, Paris, France
| | - Guillaume Dorval
- Université Paris Cité, institut Imagine, laboratoire des maladies rénales héréditaires, Inserm UMR1163, Paris, France - Service de génétique moléculaire, AP-HP, hôpital Necker-Enfants Malades, Paris, France
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4
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Nirwane A, Yao Y. Cell-specific expression and function of laminin at the neurovascular unit. J Cereb Blood Flow Metab 2022; 42:1979-1999. [PMID: 35796497 PMCID: PMC9580165 DOI: 10.1177/0271678x221113027] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/08/2022] [Accepted: 06/19/2022] [Indexed: 11/17/2022]
Abstract
Laminin, a major component of the basal lamina (BL), is a heterotrimeric protein with many isoforms. In the CNS, laminin is expressed by almost all cell types, yet different cells synthesize distinct laminin isoforms. By binding to its receptors, laminin exerts a wide variety of important functions. However, due to the reciprocal and cell-specific expression of laminin in different cells at the neurovascular unit, its functions in blood-brain barrier (BBB) maintenance and BBB repair after injury are not fully understood. In this review, we focus on the expression and functions of laminin and its receptors in the neurovascular unit under both physiological and pathological conditions. We first briefly introduce the structures of laminin and its receptors. Next, the expression and functions of laminin and its receptors in the CNS are summarized in a cell-specific manner. Finally, we identify the knowledge gap in the field and discuss key questions that need to be answered in the future. Our goal is to provide a comprehensive overview on cell-specific expression of laminin and its receptors in the CNS and their functions on BBB integrity.
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Affiliation(s)
- Abhijit Nirwane
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Yao Yao
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
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5
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Sugden CJ, Iorio V, Troughton LD, Liu K, Morais MRPT, Lennon R, Bou-Gharios G, Hamill KJ. Laminin N-terminus α31 expression during development is lethal and causes widespread tissue-specific defects in a transgenic mouse model. FASEB J 2022; 36:e22318. [PMID: 35648586 PMCID: PMC9328196 DOI: 10.1096/fj.202002588rrr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 03/28/2022] [Accepted: 04/05/2022] [Indexed: 11/11/2022]
Abstract
Laminins (LMs) are essential components of all basement membranes where they regulate an extensive array of tissue functions. Alternative splicing from the laminin α3 gene produces a non‐laminin but netrin‐like protein, Laminin N terminus α31 (LaNt α31). LaNt α31 is widely expressed in intact tissue and is upregulated in epithelial cancers and during wound healing. In vitro functional studies have shown that LaNt α31 can influence numerous aspects of epithelial cell behavior via modifying matrix organization, suggesting a new model of laminin auto‐regulation. However, the function of this protein has not been established in vivo. Here, a mouse transgenic line was generated using the ubiquitin C promoter to drive inducible expression of LaNt α31. When expression was induced at embryonic day 15.5, LaNt α31 transgenic animals were not viable at birth, exhibiting localized regions of erythema. Histologically, the most striking defect was widespread evidence of extravascular bleeding across multiple tissues. Additionally, LaNt α31 transgene expressing animals exhibited kidney epithelial detachment, tubular dilation, disruption of the epidermal basal cell layer and of the hair follicle outer root sheath, and ~50% reduction of cell numbers in the liver, associated with depletion of hematopoietic erythrocytic foci. These findings provide the first in vivo evidence that LaNt α31 can influence tissue morphogenesis.
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Affiliation(s)
- Conor J Sugden
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Valentina Iorio
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Lee D Troughton
- Department of Cell and Molecular Physiology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois, USA
| | - Ke Liu
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Mychel R P T Morais
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, The University of Manchester, Manchester, UK
| | - Rachel Lennon
- Wellcome Centre for Cell-Matrix Research, Division of Cell-Matrix Biology and Regenerative Medicine, The University of Manchester, Manchester, UK
| | - George Bou-Gharios
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Kevin J Hamill
- Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
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6
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Serjanov D, Bachay G, Hunter DD, Brunken WJ. Laminin β2 Chain Regulates Cell Cycle Dynamics in the Developing Retina. Front Cell Dev Biol 2022; 9:802593. [PMID: 35096830 PMCID: PMC8790539 DOI: 10.3389/fcell.2021.802593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Accepted: 12/20/2021] [Indexed: 11/18/2022] Open
Abstract
Vertebrate retinal development follows a highly stereotyped pattern, in which the retinal progenitor cells (RPCs) give rise to all retinal types in a conserved temporal sequence. Ensuring the proper control over RPC cell cycle exit and re-entry is, therefore, crucially important for the generation of properly functioning retina. In this study, we demonstrate that laminins, indispensible ECM components, at the retinal surface, regulate the mechanisms determining whether RPCs generate proliferative or post-mitotic progeny. In vivo deletion of laminin β2 in mice resulted in disturbing the RPC cell cycle dynamics, and premature cell cycle exit. Specifically, the RPC S-phase is shortened, with increased numbers of cells present in its late stages. This is followed by an accelerated G2-phase, leading to faster M-phase entry. Finally, the M-phase is extended, with RPCs dwelling longer in prophase. Addition of exogenous β2-containing laminins to laminin β2-deficient retinal explants restored the appropriate RPC cell cycle dynamics, as well as S and M-phase progression, leading to proper cell cycle re-entry. Moreover, we show that disruption of dystroglycan, a laminin receptor, phenocopies the laminin β2 deletion cell cycle phenotype. Together, our findings suggest that dystroglycan-mediated ECM signaling plays a critical role in regulating the RPC cell cycle dynamics, and the ensuing cell fate decisions.
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Affiliation(s)
- Dmitri Serjanov
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, United States
| | - Galina Bachay
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, United States
| | - Dale D Hunter
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, United States
| | - William J Brunken
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, United States
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7
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Boyer O, Mollet G, Dorval G. Neurological involvement in monogenic podocytopathies. Pediatr Nephrol 2021; 36:3571-3583. [PMID: 33791874 DOI: 10.1007/s00467-020-04903-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 10/27/2020] [Accepted: 12/11/2020] [Indexed: 01/22/2023]
Abstract
Genetic studies of hereditary nephrotic syndrome (NS) have identified more than 50 genes that, if mutated, are responsible for monogenic forms of steroid-resistant NS (SRNS), either isolated or syndromic. Most of these genes encode proteins expressed in the podocyte with various functions such as transcription factors, mitochondrial proteins, or enzymes, but mainly structural proteins of the slit diaphragm (SD) as well as cytoskeletal binding and regulator proteins. Syndromic NS is sometimes associated with neurological features. Over recent decades, various studies have established links between the physiology of podocytes and neurons, both morphologically (slit diaphragm and synapse) and functionally (signaling platforms). Variants in genes expressed in different compartments of the podocyte and neurons are responsible for phenotypes associating kidney lesions with proteinuria (mainly Focal and Segmental Glomerulosclerosis (FSGS) or Diffuse Mesangial Sclerosis (DMS)) and central and/or peripheral neurological disorders. The Galloway-Mowat syndrome (GAMOS, OMIM#251300) associates neurological defects, microcephaly, and proteinuria and is caused by variants in genes encoding proteins of various functions (microtubule cytoskeleton regulation (WDR73), regulation of protein synthesis via transfer RNAs (KEOPS and WDR4 complexes)). Pierson syndrome (OMIM#609049) associating congenital nephrotic syndrome and central neurological and ophthalmological anomalies is secondary to variants in LAMB2, involved in glomerular and ocular basement membranes. Finally, Charcot-Marie-Tooth-FSGS (OMIM#614455) combines peripheral sensory-motor neuropathy and proteinuria and arises from INF2 variants, resulting in cytoskeletal polymerization defects. This review focuses on genetic syndromes associating nephrotic range proteinuria and neurological involvement and provides the latest advances in the description of these neuro-renal disorders.
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Affiliation(s)
- Olivia Boyer
- Service de Néphrologie Pédiatrique, AP-HP, Centre de Référence de maladies rénales rares de l'enfant et de l'adulte (MARHEA), Hôpital Necker - Enfants Malades, 149 Rue de Sèvres, 75015, Paris, France.
- Institut Imagine, Laboratoire des maladies rénales héréditaires, INSERM UMR 1163, Université de Paris, Paris, France.
| | - Géraldine Mollet
- Institut Imagine, Laboratoire des maladies rénales héréditaires, INSERM UMR 1163, Université de Paris, Paris, France
| | - Guillaume Dorval
- Institut Imagine, Laboratoire des maladies rénales héréditaires, INSERM UMR 1163, Université de Paris, Paris, France
- Service de Génétique Moléculaire, AP-HP, Hôpital Necker-Enfants Malades, Paris, France
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8
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Quantitative proteomic analysis to identify differentially expressed proteins in patients with epilepsy. Epilepsy Res 2021; 174:106674. [PMID: 34029912 DOI: 10.1016/j.eplepsyres.2021.106674] [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: 01/14/2021] [Revised: 04/19/2021] [Accepted: 05/13/2021] [Indexed: 01/16/2023]
Abstract
There is a great need for biomarkers in epilepsy, particularly markers of epileptogenesis. A first seizure will lead to epilepsy in 20-45 % of cases, but biomarkers that can identify these individuals are missing. The purpose of this study was to identify potential biomarkers of epilepsy/epileptogenesis in a cohort of adults with new-onset seizures, using quantitative proteomic analysis. Plasma was collected from 55 adults with new-onset seizures and sufficient follow-up to identify epilepsy. After a follow up period of two years, 63.6 % of the cohort had a diagnosis of epilepsy, whereas 36.4 % of patients only had a single seizure. Plasma proteins were extracted and labelled with tandem mass tags, then analyzed using mass spectrometry approach. Proteins that were up- or downregulated by ≥20 % and with a p-value of <0.05 were considered as differentially expressed and were also annotated to their processes and pathways. Several proteins were differentially expressed in the epilepsy group compared to controls. A total of 1075 proteins were detected, out of which 41 proteins were found to be significantly dysregulated in epilepsy patients. Many of these have been identified in experimental studies of epilepogenesis. We report plasma proteome profiling in new-onset epilepsy in a pilot study with 55 individuals. The identified proteins could be involved in pathways associated with epileptogenesis. The results should be seen as hypothesis-generating and targeted, confirmatory studies are needed.
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9
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Zhang KY, Johnson TV. The internal limiting membrane: Roles in retinal development and implications for emerging ocular therapies. Exp Eye Res 2021; 206:108545. [PMID: 33753089 DOI: 10.1016/j.exer.2021.108545] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 03/02/2021] [Accepted: 03/16/2021] [Indexed: 12/17/2022]
Abstract
Basement membranes help to establish, maintain, and separate their associated tissues. They also provide growth and signaling substrates for nearby resident cells. The internal limiting membrane (ILM) is the basement membrane at the ocular vitreoretinal interface. While the ILM is essential for normal retinal development, it is dispensable in adulthood. Moreover, the ILM may constitute a significant barrier to emerging ocular therapeutics, such as viral gene therapy or stem cell transplantation. Here we take a neurodevelopmental perspective in examining how retinal neurons, glia, and vasculature interact with individual extracellular matrix constituents at the ILM. In addition, we review evidence that the ILM may impede novel ocular therapies and discuss approaches for achieving retinal parenchymal targeting of gene vectors and cell transplants delivered into the vitreous cavity by manipulating interactions with the ILM.
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Affiliation(s)
- Kevin Y Zhang
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Maumenee B-110, Baltimore, MD, 21287, USA
| | - Thomas V Johnson
- Glaucoma Center of Excellence, Wilmer Eye Institute, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Maumenee B-110, Baltimore, MD, 21287, USA.
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10
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AlTaisan A, Magliyah M, Abouammoh MA, Taskintuna I, Alzahrani Y, Chang E, Alsulaiman SM. Posterior Segment Characterization in Children With Pierson Syndrome. Ophthalmic Surg Lasers Imaging Retina 2020; 51:618-627. [DOI: 10.3928/23258160-20201104-03] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 09/10/2020] [Indexed: 01/25/2023]
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11
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Enhanced proliferation and differentiation of neural stem cells by peptide-containing temperature-sensitive hydrogel scaffold. MATERIALS SCIENCE & ENGINEERING. C, MATERIALS FOR BIOLOGICAL APPLICATIONS 2020; 116:111258. [PMID: 32806302 DOI: 10.1016/j.msec.2020.111258] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Revised: 06/29/2020] [Accepted: 06/30/2020] [Indexed: 01/03/2023]
Abstract
Hydrogel has attracted great attention in the past few years as a widely used material for repairing central nerve damage. However, conventional hydrogel bio-scaffold, such as chitosan, gelatin, and sodium alginate, lack sufficient biological activity and have limited nerve repair capabilities. Therefore, to explore biologically active and intelligent hydrogel materials is particularly important and necessary for central nerve repair. Herein, we developed a temperature-sensitive hydrogel grafted with a bioactive peptide IKVAV (Ile-Lys-Val-Ala-Val, IKVAV). The hydrogel was prepared by copolymerization of N-propan-2-ylprop-2-enamide (NIPAM) and AC-PEG-IKVAV copolymers via reversible addition-fracture chain transfer (RAFT) polymerization, using polyethylene glycol (PEGDA) and N, N'-Methylenebisacrylamide (BISAM) as cross-linking agents. The prepared hydrogel scaffold demonstrates a series of excellent properties such as rapid (de)swelling performance, good biocompatibility, regular three-dimensional porous structure, and in particular good biological activity, which can guide cell fate and mediate neuron's differentiation. Therefore, the developed peptide hydrogel scaffold provides a new strategy for designing biomaterials that are widely used in tissue engineering for central nervous system injury.
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Liu Y, Yu M, Shang X, Nguyen MHH, Balakrishnan S, Sager R, Hu H. Eyes shut homolog (EYS) interacts with matriglycan of O-mannosyl glycans whose deficiency results in EYS mislocalization and degeneration of photoreceptors. Sci Rep 2020; 10:7795. [PMID: 32385361 PMCID: PMC7210881 DOI: 10.1038/s41598-020-64752-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 04/21/2020] [Indexed: 12/12/2022] Open
Abstract
Mutations in eyes shut homolog (EYS), a secreted extracellular matrix protein containing multiple laminin globular (LG) domains, and in protein O-mannose β1, 2-N-acetylglucosaminyl transferase 1 (POMGnT1), an enzyme involved in O-mannosyl glycosylation, cause retinitis pigmentosa (RP), RP25 and RP76, respectively. How EYS and POMGnT1 regulate photoreceptor survival is poorly understood. Since some LG domain-containing proteins function by binding to the matriglycan moiety of O-mannosyl glycans, we hypothesized that EYS interacted with matriglycans as well. To test this hypothesis, we performed EYS Far-Western blotting assay and generated pomgnt1 mutant zebrafish. The results showed that EYS bound to matriglycans. Pomgnt1 mutation in zebrafish resulted in a loss of matriglycan, retention of synaptotagmin-1-positive EYS secretory vesicles within the outer nuclear layer, and diminished EYS protein near the connecting cilia. Photoreceptor density in 2-month old pomgnt1 mutant retina was similar to the wild-type animals but was significantly reduced at 6-months. These results indicate that EYS protein localization to the connecting cilia requires interaction with the matriglycan and that O-mannosyl glycosylation is required for photoreceptor survival in zebrafish. This study identified a novel interaction between EYS and matriglycan demonstrating that RP25 and RP76 are mechanistically linked in that O-mannosyl glycosylation controls targeting of EYS protein.
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Affiliation(s)
- Yu Liu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
| | - Miao Yu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
| | - Xuanze Shang
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
| | - My Hong Hoai Nguyen
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
- Department of Biological Sciences, State University of New York at Plattsburgh, 101 Broad St., Plattsburgh, New York, 12901, USA
| | - Shanmuganathan Balakrishnan
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
| | - Rachel Sager
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA
| | - Huaiyu Hu
- Center for Vision Research, Departments of Neuroscience and Physiology and of Ophthalmology and Visual Sciences, Upstate Medical University, Syracuse, NY, 13210, USA.
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13
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Affiliation(s)
- Minkyung Kang
- From the Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA
| | - Yao Yao
- From the Department of Pharmaceutical and Biomedical Sciences, University of Georgia, Athens, GA
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14
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Tahoun M, Chandler JC, Ashton E, Haston S, Hannan A, Kim JS, D’Arco F, Bockenhauer D, Anderson G, Lin MH, Marzouk S, Saied MH, Miner JH, Dattani MT, Waters AM. Mutations in LAMB2 Are Associated With Albuminuria and Optic Nerve Hypoplasia With Hypopituitarism. J Clin Endocrinol Metab 2020; 105:5643661. [PMID: 31769495 PMCID: PMC7048679 DOI: 10.1210/clinem/dgz216] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 11/25/2019] [Indexed: 01/15/2023]
Abstract
CONTEXT Mutations in LAMB2, encoding the basement membrane protein, laminin β2, are associated with an autosomal recessive disorder characterized by congenital nephrotic syndrome, ocular abnormalities, and neurodevelopmental delay (Pierson syndrome). CASE DESCRIPTION This report describes a 12-year-old boy with short stature, visual impairment, and developmental delay who presented with macroscopic hematuria and albuminuria. He had isolated growth hormone deficiency, optic nerve hypoplasia, and a small anterior pituitary with corpus callosum dysgenesis on his cranial magnetic resonance imaging, thereby supporting a diagnosis of optic nerve hypoplasia syndrome. Renal histopathology revealed focal segmental glomerulosclerosis. Using next-generation sequencing on a targeted gene panel for steroid-resistant nephrotic syndrome, compound heterozygous missense mutations were identified in LAMB2 (c.737G>A p.Arg246Gln, c.3982G>C p.Gly1328Arg). Immunohistochemical analysis revealed reduced glomerular laminin β2 expression compared to control kidney and a thin basement membrane on electron microscopy. Laminin β2 is expressed during pituitary development and Lamb2-/- mice exhibit stunted growth, abnormal neural retinae, and here we show, abnormal parenchyma of the anterior pituitary gland. CONCLUSION We propose that patients with genetically undefined optic nerve hypoplasia syndrome should be screened for albuminuria and, if present, screened for mutations in LAMB2.
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Affiliation(s)
- Mona Tahoun
- Clinical and Chemical Pathology Department, Faculty of Medicine, Alexandria University, Egypt
| | - Jennifer C Chandler
- UCL Great Ormond Street Institute of Child Health, University College London, UK
| | - Emma Ashton
- Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | - Scott Haston
- UCL Great Ormond Street Institute of Child Health, University College London, UK
| | - Athia Hannan
- Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | - Ji Soo Kim
- UCL Great Ormond Street Institute of Child Health, University College London, UK
| | - Felipe D’Arco
- Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | - D Bockenhauer
- Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | - G Anderson
- Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | - Meei-Hua Lin
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St Louis, Missouri
| | - Salah Marzouk
- Clinical and Chemical Pathology Department, Faculty of Medicine, Alexandria University, Egypt
| | - Marwa H Saied
- Clinical and Chemical Pathology Department, Faculty of Medicine, Alexandria University, Egypt
| | - Jeffrey H Miner
- Division of Nephrology, Department of Medicine, Washington University School of Medicine, St Louis, Missouri
| | - Mehul T Dattani
- UCL Great Ormond Street Institute of Child Health, University College London, UK
- Great Ormond Street Hospital NHS Foundation Trust, London, UK
| | - Aoife M Waters
- UCL Great Ormond Street Institute of Child Health, University College London, UK
- Great Ormond Street Hospital NHS Foundation Trust, London, UK
- Correspondence: Aoife Waters, MB, BAO, MSc, PhD, FRCPCH, Programme of Developmental Biology of Birth Defects, UCL Great Ormond Street Institute of Child Health, London WC1N 1EH, UK; Consultant Paediatric Nephrologist, Great Ormond Street Hospital NHS Foundation Trust, London, UK. E-mail: ;
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15
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Sijilmassi O, López-Alonso JM, Barrio Asensio MDC, Del Río Sevilla A. Alteration of lens and retina textures from mice embryos with folic acid deficiency: image processing analysis. Graefes Arch Clin Exp Ophthalmol 2018; 257:111-123. [PMID: 30392021 DOI: 10.1007/s00417-018-4176-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 10/15/2018] [Accepted: 10/25/2018] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Folic acid (FA) is an essential vitamin for embryonic development. It plays particularly a critical role in RNA, DNA and protein synthesis. On the other hand, the collagen IV and laminin-1 are important proteins during embryonic development. This study was done to find if FA deficiency at a short and a long term in mothers could alter the tissue texture of retina and lens of the progeny. METHODS Collagen IV and laminin-1 were localized by immunohistochemistry in the lens and retina of the FA-deficient embryos. To carry out the image processing, texture segmentation was performed through canny edge detection and Fourier transform (FT). We defined a parameter, the grain size, to describe the texture of the lens and retina. A bootstrap method to estimate the distribution and confidence intervals of the mean, standard deviation, skewness and kurtosis of the grain size has been developed. RESULTS Analysis through image processing using Matlab showed changes in the grain size between control- and FA-deficient groups in both studied molecules. Measures of texture based on FT exhibited changes in the directionality and arrangements of type IV collagen and laminin-1. CONCLUSIONS Changes introduced by FA deficiency were visible in the short term (2 weeks) and evident in the long term (8 weeks) in both grain size and orientation of fibre structures in the tissues analysed (lens and retina). This is the first work devoted to study the effect of FA deficit in the texture of eye tissues using image processing techniques.
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Affiliation(s)
- Ouafa Sijilmassi
- Faculty of Optics and Optometry, Anatomy and Human Embryology Department, Universidad Complutense De Madrid, Avda. Arcos de Jalón, 118, 28037, Madrid, Spain. .,Faculty of Optics and Optometry, Optics Department, Universidad Complutense De Madrid, Avda. Arcos de Jalón, 118, 28037, Madrid, Spain.
| | - José Manuel López-Alonso
- Faculty of Optics and Optometry, Optics Department, Universidad Complutense De Madrid, Avda. Arcos de Jalón, 118, 28037, Madrid, Spain
| | - María Del Carmen Barrio Asensio
- Faculty of Optics and Optometry, Anatomy and Human Embryology Department, Universidad Complutense De Madrid, Avda. Arcos de Jalón, 118, 28037, Madrid, Spain
| | - Aurora Del Río Sevilla
- Faculty of Optics and Optometry, Anatomy and Human Embryology Department, Universidad Complutense De Madrid, Avda. Arcos de Jalón, 118, 28037, Madrid, Spain
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16
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Extracellular matrix component expression in human pluripotent stem cell-derived retinal organoids recapitulates retinogenesis in vivo and reveals an important role for IMPG1 and CD44 in the development of photoreceptors and interphotoreceptor matrix. Acta Biomater 2018; 74:207-221. [PMID: 29777959 DOI: 10.1016/j.actbio.2018.05.023] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 05/07/2018] [Accepted: 05/15/2018] [Indexed: 02/08/2023]
Abstract
The extracellular matrix (ECM) plays an important role in numerous processes including cellular proliferation, differentiation, migration, maturation, adhesion guidance and axonal growth. To date, there has been no detailed analysis of the ECM distribution during retinal ontogenesis in humans and the functional importance of many ECM components is poorly understood. In this study, the expression of key ECM components in adult mouse and monkey retina, developing and adult human retina and retinal organoids derived from human pluripotent stem cells was studied. Our data indicate that basement membrane ECMs (Fibronectin and Collagen IV) were expressed in Bruch's membrane and the inner limiting membrane of the developing human retina, whilst the hyalectins (Versican and Brevican), cluster of differentiation 44 (CD44), photoreceptor-specific ECMs Interphotoreceptor Matrix Proteoglycan 1 (IMPG1) and Interphotoreceptor Matrix Proteoglycan 2 (IMPG2) were detected in the developing interphotoreceptor matrix (IPM). The expression of IMPG1, Versican and Brevican in the developing IPM was conserved between human developing retina and human pluripotent stem cell-derived retinal organoids. Blocking the action of CD44 and IMPG1 in pluripotent stem cell derived retinal organoids affected the development of photoreceptors, their inner/outer segments and connecting cilia and disrupted IPM formation, with IMPG1 having an earlier and more significant impact. Together, our data suggest an important role for IMPG1 and CD44 in the development of photoreceptors and IPM formation during human retinogenesis. STATEMENT OF SIGNIFICANCE The expression and the role of many extracellular matrix (ECM) components during human retinal development is not fully understood. In this study, expression of key ECM components (Collagen IV, Fibronectin, Brevican, Versican, IMPG1 and IMPG2) was investigated during human retinal ontogenesis. Collagen IV and Fibronectin were expressed in Bruch's membrane; whereas Brevican, Versican, IMPG1 & IMPG2 in the developing interphotoreceptor matrix (IPM). Retinal organoids were successfully generated from pluripotent stem cells. The expression of ECM components was examined in the retinal organoids and found to recapitulate human retinal development in vivo. Using functional blocking experiments, we were able to highlight an important role for IMPG1 and CD44 in the development of photoreceptors and IPM formation.
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17
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EVALUATION OF FULL-FIELD ELECTRORETINOGRAM REDUCTIONS AFTER OCRIPLASMIN TREATMENT: Results of the OASIS Trial ERG Substudy. Retina 2018; 38:364-378. [PMID: 28198785 PMCID: PMC5841857 DOI: 10.1097/iae.0000000000001536] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The Ocriplasmin for Treatment for Symptomatic Vitreomacular Adhesion Including Macular Hole (OASIS) trial electroretinogram substudy assessed a possible association between vitreomacular adhesion and best-corrected visual acuity with changes to full-field electroretinograms as part of a prospective, randomized, double-masked, sham-controlled clinical trial studying the efficacy and safety of ocriplasmin for the treatment of symptomatic vitreomacular adhesion. Purpose: To explore a possible association between full-field electroretinograms with vitreomacular adhesion resolution and best-corrected visual acuity as part of the prospective, randomized, double-masked, sham-controlled Ocriplasmin for Treatment for Symptomatic Vitreomacular Adhesion Including Macular Hole (OASIS) trial studying ocriplasmin. Methods: The ERG substudy enrolled 62 of 220 OASIS subjects (randomized 2:1) and analyzed full-field electroretinograms and their association with both vitreomacular adhesion resolution and best-corrected visual acuity from baseline through Month 24. Electroretinogram reductions were defined as acute full-field electroretinogram reductions in amplitude of ≥40% from baseline occurring at postinjection Day 7 or Day 28. Results: In the ocriplasmin group, 16/40 (40%) subjects developed ERG reductions, compared to 1/21 (4.8%) in the sham group; 13/16 (81.3%) and 1/1 (100%) resolved by study end, respectively. A total of 11/16 (68.8%) ocriplasmin-treated subjects with ERG reductions achieved vitreomacular adhesion resolution, compared to those without (9/24, 37.5%). The ocriplasmin-treated subjects with ERG reductions also gained more letters on average (11.3 vs. 9.3 letters) from baseline and had a difference of 6.7 letters in mean best-corrected visual acuity by study end compared to those without ERG reductions. Conclusion: Ocriplasmin-treated subjects with ERG reductions had a higher rate of vitreomacular adhesion resolution and showed better visual improvement than their counterparts without ERG reductions or sham subjects by study end.
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18
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Dorgau B, Felemban M, Sharpe A, Bauer R, Hallam D, Steel DH, Lindsay S, Mellough C, Lako M. Laminin γ3 plays an important role in retinal lamination, photoreceptor organisation and ganglion cell differentiation. Cell Death Dis 2018; 9:615. [PMID: 29795281 PMCID: PMC5966411 DOI: 10.1038/s41419-018-0648-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Revised: 04/12/2018] [Accepted: 04/26/2018] [Indexed: 01/02/2023]
Abstract
Laminins are heterotrimeric glycoproteins of the extracellular matrix. Eleven different laminin chains have been identified in vertebrates. They are ubiquitously expressed in the human body, with a distinct tissue distribution. Laminin expression in neural retina and their functional role during human retinogenesis is still unknown. This study investigated the laminin expression in human developing and adult retina, showing laminin α1, α5, β1, β2 and γ1 to be predominantly expressed in Bruch's membrane and the inner limiting membrane. Laminin-332 and laminin γ3 expression were mainly observed in the neural retina during retinal histogenesis. These expression patterns were largely conserved in pluripotent stem cell-derived retinal organoids. Blocking of laminin γ3 function in retinal organoids resulted in the disruption of laminar organisation and synapse formation, the loss of photoreceptor organisation and retinal ganglion cells. Our data demonstrate a unique temporal and spatial expression for laminins and reveal a novel role for laminin γ3 during human retinogenesis.
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Affiliation(s)
- Birthe Dorgau
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Majed Felemban
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Alexander Sharpe
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Roman Bauer
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Dean Hallam
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - David H Steel
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Susan Lindsay
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Carla Mellough
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom
- Lions Eye Institute, Centre for Ophthalmology and Visual Science, University of Western Australia, Nedlands WA, Australia
| | - Majlinda Lako
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom.
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Assessment of Ocriplasmin Effects on the Vitreoretinal Compartment in Porcine and Human Model Systems. J Ophthalmol 2017; 2017:2060765. [PMID: 29214073 PMCID: PMC5682056 DOI: 10.1155/2017/2060765] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Accepted: 09/17/2017] [Indexed: 11/17/2022] Open
Abstract
Ocriplasmin (Jetrea®) is a recombinant protease used to treat vitreomacular traction. To gain insight into vitreoretinal observations reported after ocriplasmin treatment, we have developed an in vivo porcine ocriplasmin-induced posterior vitreous detachment (PVD) model in which we investigated vitreoretinal tissues by optical coherence tomography, histology, and cytokine profiling. Eight weeks postinjection, ocriplasmin yielded PVD in 82% of eyes. Subretinal fluid (85%) and vitreous hyperreflective spots (45%) were resolved by week 3. Histological analysis of extracellular matrix (ECM) proteins such as laminin, fibronectin, and collagen IV indicated no retinal ocriplasmin-induced ECM distribution changes. Retinal morphology was unaffected in all eyes. Cytokine profiles of ocriplasmin-treated eyes were not different from vehicle. In cell-based electrical resistance assays, blood-retinal barrier permeability was altered by ocriplasmin concentrations of 6 μg/mL and higher, with all effects being nontoxic, cell-type specific, and reversible. Ocriplasmin was actively taken up by RPE and Müller cells, and our data suggest both lysosomal and transcellular clearance routes for ocriplasmin. In conclusion, transient hyperreflective spots and fluid in a porcine ocriplasmin-induced PVD model did not correlate with retinal ECM rearrangement nor inflammation. Reversible in vitro effects on blood-retinal barrier permeability provide grounds for a hypothesis on the mechanisms behind transient subretinal fluid observed in ocriplasmin-treated patients.
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20
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Hunter DD, Manglapus MK, Bachay G, Claudepierre T, Dolan MW, Gesuelli KA, Brunken WJ. CNS synapses are stabilized trans-synaptically by laminins and laminin-interacting proteins. J Comp Neurol 2017; 527:67-86. [PMID: 29023785 DOI: 10.1002/cne.24338] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 09/21/2017] [Accepted: 09/29/2017] [Indexed: 01/05/2023]
Abstract
The retina expresses several laminins in the outer plexiform layer (OPL), where they may provide an extracellular scaffold for synapse stabilization. Mice with a targeted deletion of the laminin β2 gene (Lamb2) exhibit retinal disruptions: photoreceptor synapses in the OPL are disorganized and the retinal physiological response is attenuated. We hypothesize that laminins are required for proper trans-synaptic alignment. To test this, we compared the distribution, expression, association and modification of several pre- and post-synaptic elements in wild-type and Lamb2-null retinae. A potential laminin receptor, integrin α3, is at the presynaptic side of the wild-type OPL. Another potential laminin receptor, dystroglycan, is at the post-synaptic side of the wild-type OPL. Integrin α3 and dystroglycan can be co-immunoprecipitated with the laminin β2 chain, demonstrating that they may bind laminins. In the absence of the laminin β2 chain, the expression of many pre-synaptic components (bassoon, kinesin, among others) is relatively undisturbed although their spatial organization and anchoring to the membrane is disrupted. In contrast, in the Lamb2-null, β-dystroglycan (β-DG) expression is altered, co-localization of β-DG with dystrophin and the glutamate receptor mGluR6 is disrupted, and the post-synaptic bipolar cell components mGluR6 and GPR179 become dissociated, suggesting that laminins mediate scaffolding of post-synaptic components. In addition, although pikachurin remains associated with β-DG, pikachurin is no longer closely associated with mGluR6 or α-DG in the Lamb2-null. These data suggest that laminins act as links among pre- and post-synaptic laminin receptors and α-DG and pikachurin in the synaptic space to maintain proper trans-synaptic alignment.
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Affiliation(s)
- Dale D Hunter
- Department of Anatomy and Cellular Biology, Tufts University and Tufts Center for Vision Research, Boston, Massachusetts.,Department of Ophthalmology and the SUNY Eye Institute, Upstate Medical University, Syracuse, New York
| | - Mary K Manglapus
- Department of Anatomy and Cellular Biology, Tufts University and Tufts Center for Vision Research, Boston, Massachusetts
| | - Galina Bachay
- Department of Ophthalmology and the SUNY Eye Institute, Upstate Medical University, Syracuse, New York
| | - Thomas Claudepierre
- Department of Anatomy and Cellular Biology, Tufts University and Tufts Center for Vision Research, Boston, Massachusetts
| | - Michael W Dolan
- Department of Ophthalmology and the SUNY Eye Institute, Upstate Medical University, Syracuse, New York
| | - Kelly-Ann Gesuelli
- Department of Ophthalmology and the SUNY Eye Institute, Upstate Medical University, Syracuse, New York
| | - William J Brunken
- Department of Anatomy and Cellular Biology, Tufts University and Tufts Center for Vision Research, Boston, Massachusetts.,Department of Ophthalmology and the SUNY Eye Institute, Upstate Medical University, Syracuse, New York
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21
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Schumann RG, Langer J, Compera D, Luedtke K, Schaumberger MM, Kreutzer T, Mayer WJ, Wolf A, Priglinger SG. Assessment of intravitreal ocriplasmin treatment for vitreomacular traction in clinical practice. Graefes Arch Clin Exp Ophthalmol 2017; 255:2081-2089. [PMID: 28755165 DOI: 10.1007/s00417-017-3747-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 06/29/2017] [Accepted: 07/05/2017] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To assess treatment effects following intravitreal injection of ocriplasmin for vitreomacular traction (VMT), with or without full-thickness macular hole (FTMH), in real-life setting. METHODS This is a monocentric, retrospective, consecutive series of 82 eyes from 82 patients who underwent ocriplasmin treatment between July 2013 and December 2016. We included 57 eyes with pure VMT, 17 eyes with small FTMHs, and eight eyes with medium FTMHs. Primary outcome measures were VMT release and MH closure rates. Secondary outcomes were visual acuity (VA), morphological changes, and subjective visual impairment after 1, 3, and 6 months and at last follow-up. RESULTS After a median follow-up of 10 months, VMT release was achieved by pharmacologic vitreolysis in 57% of all eyes, whereas the macular hole closure rate was 32%. In those presenting with five or more positive prognostic factors (PPF), eyes with pure VMT showed nonsurgical traction release in 88%, and FTMHs were released in 93%, with a closure rate of 20%. Small FTMHs closed in 41% and medium FTMHs in 13%. The mean change in VA (LogMAR) was -0.07 ± 0.24 (median - 0.10) in all eyes. Subretinal fluid accumulation and ellipsoid zone changes were seen in 31% and 37% of all eyes, respectively. They were more frequent in eyes with traction release, but were self-limited. CONCLUSIONS In a real-life setting, release of VMT by ocriplasmin injection can be achieved in the majority of eyes, relying on a strict patient selection. Closure of FTMHs rather correlates with hole diameter than with presence of PPF, and remains a rare finding in medium FTMHs.
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Affiliation(s)
- Ricarda G Schumann
- Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany.
| | - Julian Langer
- Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany
| | - Denise Compera
- Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany
| | - Katharina Luedtke
- Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany
| | - Markus M Schaumberger
- Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany
| | - Thomas Kreutzer
- Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany
| | - Wolfgang J Mayer
- Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany
| | - Armin Wolf
- Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany
| | - Siegfried G Priglinger
- Department of Ophthalmology, Ludwig-Maximilians-University, Mathildenstrasse 8, 80336, Munich, Germany
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22
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Kino J, Tsukaguchi H, Kimata T, Nguyen HT, Nakano Y, Miyake N, Matsumoto N, Kaneko K. Nephron development and extrarenal features in a child with congenital nephrotic syndrome caused by null LAMB2 mutations. BMC Nephrol 2017; 18:220. [PMID: 28683731 PMCID: PMC5501564 DOI: 10.1186/s12882-017-0632-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 06/22/2017] [Indexed: 01/15/2023] Open
Abstract
BACKGROUND Congenital nephrotic syndrome (CNS) is a rare disorder caused by various structural and developmental defects of glomeruli. It occurs typically as an isolated kidney disorder but associates sometimes with other systemic, extrarenal manifestations. CASE PRESENTATIONS An infant presented with severe CNS, which progressed rapidly to renal failure at age of 3 months and death at 27 months. The clinical phenotypes and genetic causes were studied, including the renal pathology at autopsy. Besides the CNS, the affected child had remarkable right-side predominant eye-ball hypoplasia with bilateral anterior chamber dysgenesis (microcoria). Brain MRI revealed grossly normal development in the cerebrum, cerebellum, and brain stem. Auditory brainstem responses were bilaterally blunted, suggesting a defective auditory system. At autopsy, both kidneys were mildly atrophied with persistent fetal lobulation. Microscopic examination showed a diffuse global sclerosis. However, despite of the smaller size of glomeruli, the nephron number remained similar to that of the age-matched control. Whole-exome sequencing revealed that the affected child was compound heterozygous for novel truncating LAMB2 mutations: a 4-bp insertion (p.Gly1693Alafs*8) and a splicing donor-site substitution (c.1225 + 1G > A), presumably deleting the coiled-coil domains that form the laminin 5-2-1 heterotrimer complex. CONCLUSIONS Our case represents a variation of Pierson syndrome that accompanies CNS with unilateral ocular hypoplasia. The average number but smaller glomeruli could reflect either mal-development or glomerulosclerosis. Heterogeneous clinical expression of LAMB2 defects may associate with the difference in fetal β1 subtype compensation among affected tissues. Further study is necessary to evaluate incidence and features of auditory defect under LAMB2 deficiency.
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Affiliation(s)
- Jiro Kino
- Department of Pediatrics, Kansai Medical University, 2-5-1 Shimachi, Hirakata, Osaka, 573-1010, Japan
| | - Hiroyasu Tsukaguchi
- Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi Hirakata, Osaka, 573-1010, Japan.
| | - Takahisa Kimata
- Department of Pediatrics, Kansai Medical University, 2-5-1 Shimachi, Hirakata, Osaka, 573-1010, Japan
| | - Huan Thanh Nguyen
- Second Department of Internal Medicine, Kansai Medical University, 2-5-1 Shinmachi Hirakata, Osaka, 573-1010, Japan
| | - Yorika Nakano
- Department of Pathology and Laboratory Medicine, Kansai Medical University, Osaka, Japan.,Present Address: Department of Histopathology and Cytology, Japanese Red Cross Kyoto Daini Hospital, Kyoto, Japan
| | - Noriko Miyake
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan
| | - Kazunari Kaneko
- Department of Pediatrics, Kansai Medical University, 2-5-1 Shimachi, Hirakata, Osaka, 573-1010, Japan
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23
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Yao Y. Laminin: loss-of-function studies. Cell Mol Life Sci 2017; 74:1095-1115. [PMID: 27696112 PMCID: PMC11107706 DOI: 10.1007/s00018-016-2381-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/25/2016] [Accepted: 09/26/2016] [Indexed: 01/13/2023]
Abstract
Laminin, one of the most widely expressed extracellular matrix proteins, exerts many important functions in multiple organs/systems and at various developmental stages. Although its critical roles in embryonic development have been demonstrated, laminin's functions at later stages remain largely unknown, mainly due to its intrinsic complexity and lack of research tools (most laminin mutants are embryonic lethal). With the advance of genetic and molecular techniques, many new laminin mutants have been generated recently. These new mutants usually have a longer lifespan and show previously unidentified phenotypes. Not only do these studies suggest novel functions of laminin, but also they provide invaluable animal models that allow investigation of laminin's functions at late stages. Here, I first briefly introduce the nomenclature, structure, and biochemistry of laminin in general. Next, all the loss-of-function mutants/models for each laminin chain are discussed and their phenotypes compared. I hope to provide a comprehensive review on laminin functions and its loss-of-function models, which could serve as a reference for future research in this understudied field.
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Affiliation(s)
- Yao Yao
- College of Pharmacy, University of Minnesota, Duluth, MN, 55812, USA.
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24
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Autoimmunity against laminins. Clin Immunol 2016; 170:39-52. [PMID: 27464450 DOI: 10.1016/j.clim.2016.07.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 04/30/2016] [Accepted: 07/22/2016] [Indexed: 12/12/2022]
Abstract
Laminins are ubiquitous constituents of the basement membranes with major architectural and functional role as supported by the fact that absence or mutations of laminins lead to either lethal or severely impairing phenotypes. Besides genetic defects, laminins are involved in a wide range of human diseases including cancer, infections, and inflammatory diseases, as well as autoimmune disorders. A growing body of evidence implicates several laminin chains as autoantigens in blistering skin diseases, collagenoses, vasculitis, or post-infectious autoimmunity. The current paper reviews the existing knowledge on autoimmunity against laminins referring to both experimental and clinical data, and on therapeutic implications of anti-laminin antibodies. Further investigation of relevant laminin epitopes in pathogenic autoimmunity would facilitate the development of appropriate diagnostic tools for thorough characterization of patients' antibody specificities and should decisively contribute to designing more specific therapeutic interventions.
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25
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Morescalchi F, Gambicorti E, Duse S, Costagliola C, Semeraro F. From the analysis of pharmacologic vitreolysis to the comprehension of ocriplasmin safety. Expert Opin Drug Saf 2016; 15:1267-78. [PMID: 27388220 DOI: 10.1080/14740338.2016.1208169] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
INTRODUCTION Pharmacologic vitreolysis is a strategy used to treat anomalous posterior vitreous detachment, by weakening vitreoretinal adhesion with an intravitreal drug. Pharmacologic vitreolysis facilitates surgery, and abnormalities of the vitreoretinal interface including vitreomacular traction (VMT) and early stage macular hole (MH) could be resolved. Ocriplasmin is a recombinant protease, active against fibronectin and laminin, which are important components of the vitreoretinal interface. Ocriplasmin has been approved for symptomatic treatment of VMT and MH with visible traction, and it functions by dissolving the proteins that link the vitreous to the macula, thereby creating a complete posterior vitreous detachment (PVD). AREAS COVERED This paper reviews the current knowledge and status of investigations regarding the use of ocriplasmin for pharmacologic vitreolysis and its safety. EXPERT OPINION Ocriplasmin is a non-specific enzyme; therefore, it dissolves vitreal proteins as well as possibly proteins associated with visual function in the retina, choroid, and lens. Ocular adverse events (OAEs) of ocriplasmin include transient visual loss, intraocular inflammation, vitreous floaters, lens opacification, zonular instability of the lens, and intraocular hemorrhage. The prevalence of the OAEs is very low; however, on rare occasions, they can result in widespread retinal dysfunction. Research into the acute and long-term safety of ocriplasmin is required.
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Affiliation(s)
- Francesco Morescalchi
- a Ophthalmology Clinic, Spedali Civili di Brescia, Department of Medical and Surgical Specialties, Radiological Specialties and Public Health , University of Brescia , Brescia , Italy
| | - Elena Gambicorti
- a Ophthalmology Clinic, Spedali Civili di Brescia, Department of Medical and Surgical Specialties, Radiological Specialties and Public Health , University of Brescia , Brescia , Italy
| | - Sarah Duse
- a Ophthalmology Clinic, Spedali Civili di Brescia, Department of Medical and Surgical Specialties, Radiological Specialties and Public Health , University of Brescia , Brescia , Italy
| | - Ciro Costagliola
- b Ophthalmology Clinic, Department of Health Science , University of Molise , Campobasso , Italy.,c Istituto Neurologico Mediterraneo, I.R.C.C.S Neuromed , Pozzilli ( Isernia ), Italy
| | - Francesco Semeraro
- a Ophthalmology Clinic, Spedali Civili di Brescia, Department of Medical and Surgical Specialties, Radiological Specialties and Public Health , University of Brescia , Brescia , Italy
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Maxeiner S, Luo F, Tan A, Schmitz F, Südhof TC. How to make a synaptic ribbon: RIBEYE deletion abolishes ribbons in retinal synapses and disrupts neurotransmitter release. EMBO J 2016; 35:1098-114. [PMID: 26929012 DOI: 10.15252/embj.201592701] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Accepted: 02/01/2016] [Indexed: 12/21/2022] Open
Abstract
Synaptic ribbons are large proteinaceous scaffolds at the active zone of ribbon synapses that are specialized for rapid sustained synaptic vesicles exocytosis. A single ribbon-specific protein is known, RIBEYE, suggesting that ribbons may be constructed from RIBEYE protein. RIBEYE knockdown in zebrafish, however, only reduced but did not eliminate ribbons, indicating a more ancillary role. Here, we show in mice that full deletion of RIBEYE abolishes all presynaptic ribbons in retina synapses. Using paired recordings in acute retina slices, we demonstrate that deletion of RIBEYE severely impaired fast and sustained neurotransmitter release at bipolar neuron/AII amacrine cell synapses and rendered spontaneous miniature release sensitive to the slow Ca(2+)-buffer EGTA, suggesting that synaptic ribbons mediate nano-domain coupling of Ca(2+) channels to synaptic vesicle exocytosis. Our results show that RIBEYE is essential for synaptic ribbons as such, and may organize presynaptic nano-domains that position release-ready synaptic vesicles adjacent to Ca(2+) channels.
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Affiliation(s)
- Stephan Maxeiner
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute Stanford University School of Medicine, Stanford, CA, USA Department of Neuroanatomy, Institute for Anatomy and Cell Biology Medical School Saarland University, Homburg/Saar, Germany
| | - Fujun Luo
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute Stanford University School of Medicine, Stanford, CA, USA
| | - Alison Tan
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute Stanford University School of Medicine, Stanford, CA, USA
| | - Frank Schmitz
- Department of Neuroanatomy, Institute for Anatomy and Cell Biology Medical School Saarland University, Homburg/Saar, Germany
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Howard Hughes Medical Institute Stanford University School of Medicine, Stanford, CA, USA
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Small KW, Shaya FS, La Fontaine M. Post-Market Experience With Ocriplasmin Including Chronic Electrophysiologic Changes. Ophthalmic Surg Lasers Imaging Retina 2015; 46:956-62. [DOI: 10.3928/23258160-20151008-09] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 06/18/2015] [Indexed: 11/20/2022]
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Chen YM, Liapis H. Focal segmental glomerulosclerosis: molecular genetics and targeted therapies. BMC Nephrol 2015; 16:101. [PMID: 26156092 PMCID: PMC4496884 DOI: 10.1186/s12882-015-0090-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 06/16/2015] [Indexed: 12/18/2022] Open
Abstract
Recent advances show that human focal segmental glomerulosclerosis (FSGS) is a primary podocytopathy caused by podocyte-specific gene mutations including NPHS1, NPHS2, WT-1, LAMB2, CD2AP, TRPC6, ACTN4 and INF2. This review focuses on genes discovered in the investigation of complex FSGS pathomechanisms that may have implications for the current FSGS classification scheme. It also recounts recent recommendations for clinical management of FSGS based on translational studies and clinical trials. The advent of next-generation sequencing promises to provide nephrologists with rapid and novel approaches for the diagnosis and treatment of FSGS. A stratified and targeted approach based on the underlying molecular defects is evolving.
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Affiliation(s)
- Ying Maggie Chen
- Renal Division, Washington University School of Medicine, 660 S. Euclid Ave., St. Louis, MO, 63110, USA.
| | - Helen Liapis
- , Nephropath, Little Rock, Arkansas
- Pathology & Immunology, Washington University School of Medicine, St. Louis, MO, USA
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Levy C, Brooks JM, Chen J, Su J, Fox MA. Cell-specific and developmental expression of lectican-cleaving proteases in mouse hippocampus and neocortex. J Comp Neurol 2014; 523:629-48. [PMID: 25349050 DOI: 10.1002/cne.23701] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 10/20/2014] [Accepted: 10/21/2014] [Indexed: 12/31/2022]
Abstract
Mounting evidence has demonstrated that a specialized extracellular matrix exists in the mammalian brain and that this glycoprotein-rich matrix contributes to many aspects of brain development and function. The most prominent supramolecular assemblies of these extracellular matrix glycoproteins are perineuronal nets, specialized lattice-like structures that surround the cell bodies and proximal neurites of select classes of interneurons. Perineuronal nets are composed of lecticans, a family of chondroitin sulfate proteoglycans that includes aggrecan, brevican, neurocan, and versican. These lattice-like structures emerge late in postnatal brain development, coinciding with the ending of critical periods of brain development. Despite our knowledge of the presence of lecticans in perineuronal nets and their importance in regulating synaptic plasticity, we know little about the development or distribution of the extracellular proteases that are responsible for their cleavage and turnover. A subset of a large family of extracellular proteases (called a disintegrin and metalloproteinase with thrombospondin motifs [ADAMTS]) is responsible for endogenously cleaving lecticans. We therefore explored the expression pattern of two aggrecan-degrading ADAMTS family members, ADAMTS15 and ADAMTS4, in the hippocampus and neocortex. Here, we show that both lectican-degrading metalloproteases are present in these brain regions and that each exhibits a distinct temporal and spatial expression pattern. Adamts15 mRNA is expressed exclusively by parvalbumin-expressing interneurons during synaptogenesis, whereas Adamts4 mRNA is exclusively generated by telencephalic oligodendrocytes during myelination. Thus, ADAMTS15 and ADAMTS4 not only exhibit unique cellular expression patterns but their developmental upregulation by these cell types coincides with critical aspects of neural development.
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Affiliation(s)
- C Levy
- Virginia Tech Carilion Research Institute, Roanoke, Virginia, 24016; Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, 24061
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Abstract
Blindness represents an increasing global problem with significant social and economic impact upon affected patients and society as a whole. In Europe, approximately one in 30 individuals experience sight loss and 75% of those are unemployed, a social burden which is very likely to increase as the population of Europe ages. Diseases affecting the retina account for approximately 26% of blindness globally and 70% of blindness in the United Kingdom. To date, there are no treatments to restore lost retinal cells and improve visual function, highlighting an urgent need for new therapeutic approaches. A pioneering breakthrough has demonstrated the ability to generate synthetic retina from pluripotent stem cells under laboratory conditions, a finding with immense relevance for basic research, in vitro disease modeling, drug discovery, and cell replacement therapies. This review summarizes the current achievements in pluripotent stem cell differentiation toward retinal cells and highlights the steps that need to be completed in order to generate human synthetic retinae with high efficiency and reproducibly from patient-specific pluripotent stem cells.
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Abstract
The b-wave is a major component of the electroretinogram that reflects the activity of depolarizing bipolar cells (DBCs). The b-wave is used diagnostically to identify patients with defects in DBC signaling or in transmission from photoreceptors to DBCs. In mouse models, an abnormal b-wave has been used to demonstrate a critical role of a particular protein in the release of glutamate from photoreceptor terminals, in establishing the structure of the photoreceptor-to-DBC synapse, in DBC signal transduction, and also in DBC development, survival, or metabolic support. The purpose of this review is to summarize these models and how they have advanced our understanding of outer retinal function.
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Hochman-Mendez C, Lacerda de Menezes JR, Sholl-Franco A, Coelho-Sampaio T. Polylaminin recognition by retinal cells. J Neurosci Res 2013; 92:24-34. [PMID: 24265135 DOI: 10.1002/jnr.23298] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Revised: 08/14/2013] [Accepted: 08/23/2013] [Indexed: 11/05/2022]
Abstract
Polylaminin (polyLM) is a flat biomimetic polymer of laminin capable of promoting axonal growth both in vitro and in vivo. It is assembled in a cell-free system when laminin 111 is incubated in acidic pH, whereas incubation in neutral buffer leads to the formation of bulky and irregular polymers (LM). In the present work, we compared the behaviors of cells isolated from the P1 rat retina on polyLM and LM. PolyLM induced cellular spreading and the outgrowth of neurites in contact with the substrate, whereas LM led to the formation of large clusters of cells, with neurites growing only inward. After 24 hr in culture, the number of cells on polyLM increased threefold, and this increase was inhibited by 60% in the presence of the PKA inhibitor H89 and by 41% in the presence of the PKC inhibitor chelerythrine chloride, whereas both inhibitors abolished neuritogenesis. Neither the cell number nor the outgrowth of neurites was affected by the ERK1/2 inhibitor PD98059 on polyLM. On the other hand, PD98059 was able to reduce the cell number on LM, whereas the other inhibitors were not. Immunostaining of P1 retina with an antilaminin antibody revealed that the protein was expressed not only at its inner surface but also within the neuroblast layer in close contact with individual cells. Our results indicate that, when provided in its active polymerized form, laminin can influence both neuritogenesis and proliferation of retinal cells.
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Affiliation(s)
- Camila Hochman-Mendez
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
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Chen YM, Zhou Y, Go G, Marmerstein JT, Kikkawa Y, Miner JH. Laminin β2 gene missense mutation produces endoplasmic reticulum stress in podocytes. J Am Soc Nephrol 2013; 24:1223-33. [PMID: 23723427 DOI: 10.1681/asn.2012121149] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Mutations in the laminin β2 gene (LAMB2) cause Pierson syndrome, a severe congenital nephrotic syndrome with ocular and neurologic defects. LAMB2 is a component of the laminin-521 (α5β2γ1) trimer, an important constituent of the glomerular basement membrane (GBM). The C321R-LAMB2 missense mutation leads to congenital nephrotic syndrome but only mild extrarenal symptoms; the mechanisms underlying the development of proteinuria with this mutation are unclear. We generated three transgenic mouse lines, in which rat C321R-LAMB2 replaced mouse LAMB2 in the GBM. During the first postnatal month, expression of C321R-LAMB2 attenuated the severe proteinuria exhibited by Lamb2(-/-) mice in a dose-dependent fashion; proteinuria eventually increased, however, leading to renal failure. The C321R mutation caused defective secretion of laminin-521 from podocytes to the GBM accompanied by podocyte endoplasmic reticulum (ER) stress, likely resulting from protein misfolding. Moreover, ER stress preceded the onset of significant proteinuria and was manifested by induction of the ER-initiated apoptotic signal C/EBP homologous protein (CHOP), ER distention, and podocyte injury. Treatment of cells expressing C321R-LAMB2 with the chemical chaperone taurodeoxycholic acid (TUDCA), which can facilitate protein folding and trafficking, greatly increased the secretion of the mutant LAMB2. Taken together, these results suggest that the mild variant of Pierson syndrome caused by the C321R-LAMB2 mutation may be a prototypical ER storage disease, which may benefit from treatment approaches that target the handling of misfolded proteins.
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Affiliation(s)
- Ying Maggie Chen
- Renal Division, Washington University School of Medicine, St. Louis, MO 63110, USA
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35
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Cheng TY, Chen MH, Chang WH, Huang MY, Wang TW. Neural stem cells encapsulated in a functionalized self-assembling peptide hydrogel for brain tissue engineering. Biomaterials 2013; 34:2005-16. [DOI: 10.1016/j.biomaterials.2012.11.043] [Citation(s) in RCA: 232] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2012] [Accepted: 11/23/2012] [Indexed: 02/08/2023]
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Abstract
The mechanisms controlling vascular development, both normal and pathological, are not yet fully understood. Many diseases, including cancer and diabetic retinopathy, involve abnormal blood vessel formation. Therefore, increasing knowledge of these mechanisms may help develop novel therapeutic targets. The identification of novel proteins or cells involved in this process would be particularly useful. The retina is an ideal model for studying vascular development because it is easy to access, particularly in rodents where this process occurs post-natally. Recent studies have suggested potential roles for laminin chains in vascular development of the retina. This review will provide an overview of these studies, demonstrating the importance of further research into the involvement of laminins in retinal blood vessel formation.
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Radner S, Banos C, Bachay G, Li YN, Hunter DD, Brunken WJ, Yee KT. β2 and γ3 laminins are critical cortical basement membrane components: Ablation of Lamb2 and Lamc3 genes disrupts cortical lamination and produces dysplasia. Dev Neurobiol 2012; 73:209-29. [DOI: 10.1002/dneu.22057] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2012] [Revised: 07/20/2012] [Accepted: 08/31/2012] [Indexed: 11/10/2022]
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Chen YM, Miner JH. Glomerular basement membrane and related glomerular disease. Transl Res 2012; 160:291-7. [PMID: 22683419 PMCID: PMC3477400 DOI: 10.1016/j.trsl.2012.03.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2011] [Revised: 02/20/2012] [Accepted: 03/15/2012] [Indexed: 01/11/2023]
Abstract
The glomerular basement membrane (GBM) is lined by fenestrated endothelium from the capillary-lumen side and by interdigitating foot processes of the podocytes from the urinary- space side. These three layers of the glomerular capillary wall constitute the functional unit of the glomerular filtration barrier. The GBM is assembled through an interweaving of type IV collagen with laminins, nidogen, and sulfated proteoglycans. Mutations in genes encoding LAMB2, COL4A3, COL4A4, and COL4A5 cause glomerular disease in humans as well as in mice. In addition, laminin α5 mutation in podocytes leads to proteinuria and renal failure in mice. Moreover, more neoepitopes in Goodpasture's disease and for the first time alloepitopes in Alport post-transplantation nephritis have been located in the collagen α5(IV) NC1 domain. These discoveries underscore the importance of the GBM in establishing and maintaining the integrity of the glomerular filtration barrier.
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Affiliation(s)
- Ying Maggie Chen
- Renal Division, Washington University School of Medicine, St. Louis, MO, USA.
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39
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Klaassen LJ, Fahrenfort I, Kamermans M. Connexin hemichannel mediated ephaptic inhibition in the retina. Brain Res 2012; 1487:25-38. [PMID: 22796289 DOI: 10.1016/j.brainres.2012.04.059] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 04/11/2012] [Indexed: 11/25/2022]
Abstract
Connexins are the building blocks of gap-junctions; sign conserving electrical synapses. Recently it has been shown that connexins can also function as hemichannels and can mediate a sign inverting inhibitory synaptic signal from horizontal cells to cones via an ephaptic mechanism. In this review we will discuss the critical requirements for such an ephaptic interaction and relate these to the available experimental evidence. The highly conserved morphological structure of the cone synapse together with a number of specific connexin proteins and proteoglycans present in the synaptic complex of the cones creates a synaptic environment that allows ephaptic interactions. The connexins involved are members of a special group of connexins, encoded by the GJA9 and GJA10 genes. Surprisingly, in contrast to many other vertebrates, mouse and other rodents seem to lack a GJA9 encoded connexin. The specific combination of substances that block feedback and the highly specific modification of feedback in a zebrafish lacking Cx55.5 hemichannels all point to an ephaptic feedback mechanism from horizontal cells to cones. This article is part of a Special Issue entitled Electrical Synapses.
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Affiliation(s)
- Lauw J Klaassen
- The Netherlands Institute for Neuroscience, Department of Retinal Signal Processing, Meibergdreef 47, 1105 BA Amsterdam, The Netherlands
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40
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Tomita K, Gotoh H, Tomita K, Yamauchi N, Sanbo M. Multiple patterns of spatiotemporal changes in layer-specific gene expression in the developing visual cortex of higher mammals. Neurosci Res 2012; 73:207-17. [PMID: 22575756 DOI: 10.1016/j.neures.2012.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 04/24/2012] [Indexed: 10/28/2022]
Abstract
The mammalian cerebral cortex, which is stratified into six layers, has functional domains that vertically span the six layers, thereby requiring tight interlaminar connectivity within a domain. The synaptic connections in individual layers are first broadly formed under predetermined programs and later reinforced between neurons which reside in the same functional domain via experience-dependent reorganization during the critical period. However, the molecular mechanisms that control these two processes within each layer are still unclear. Therefore, we performed a differential screen for candidates and found seven genes with layer-specific expression during postnatal development of cat visual cortex. APLP1, a transmembrane protein mediating synaptogenesis, started dual-layer expression in layers 2/3 and 5 before the critical period, suggesting that it might execute coarse synapse formation of these layers. STMN2 (SCG10), which promotes microtubule turnover, was unique, as it dramatically shifted its dual-layer distribution from layers 2/3 and 5 to the deeper layers 4 and 6 at the onset of the critical period; it lost this new expression pattern in the adult. Surprisingly, brief dark rearing disturbed the shift in its dual-layer distribution around the onset of the critical period. Thus, by accelerating structural remodeling, STMN2 (SCG10) might launch experience-dependent reorganization of particular layers.
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Affiliation(s)
- Koichi Tomita
- Center for Genetic Analysis of Behavior, National Institute for Physiological Sciences, 5-1 Higashiyama, Myodaiji-cho, Okazaki, Aichi 444-8787, Japan.
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The dynamic architecture of photoreceptor ribbon synapses: cytoskeletal, extracellular matrix, and intramembrane proteins. Vis Neurosci 2012; 28:453-71. [PMID: 22192503 DOI: 10.1017/s0952523811000356] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Rod and cone photoreceptors possess ribbon synapses that assist in the transmission of graded light responses to second-order bipolar and horizontal cells of the vertebrate retina. Proper functioning of the synapse requires the juxtaposition of presynaptic release sites immediately adjacent to postsynaptic receptors. In this review, we focus on the synaptic, cytoskeletal, and extracellular matrix proteins that help to organize photoreceptor ribbon synapses in the outer plexiform layer. We examine the proteins that foster the clustering of release proteins, calcium channels, and synaptic vesicles in the presynaptic terminals of photoreceptors adjacent to their postsynaptic contacts. Although many proteins interact with one another in the presynaptic terminal and synaptic cleft, these protein-protein interactions do not create a static and immutable structure. Instead, photoreceptor ribbon synapses are remarkably dynamic, exhibiting structural changes on both rapid and slow time scales.
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Li YN, Radner S, French MM, Pinzón-Duarte G, Daly GH, Burgeson RE, Koch M, Brunken WJ. The γ3 chain of laminin is widely but differentially expressed in murine basement membranes: expression and functional studies. Matrix Biol 2011; 31:120-34. [PMID: 22222602 DOI: 10.1016/j.matbio.2011.12.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2011] [Revised: 12/09/2011] [Accepted: 12/09/2011] [Indexed: 10/14/2022]
Abstract
Laminins are heterotrimeric extracellular glycoproteins found in, but not confined to, basement membranes (BMs). They are important components in formation of the molecular networks of BMs as well as in cell polarity, cell differentiation and tissue morphogenesis. Each laminin is composed by an α, a β and a γ chain. Previous studies have shown that the γ3 chain is partnered with either the β1 chain (in placenta) or β2 chain (in the CNS) (Libby et al., 2000). Several studies, including our own, suggested that the γ3 chain is expressed in both apical and basal compartments (Koch et al., 1999; Gersdorff et al., 2005; Yan and Cheng, 2006). This study investigates the expression pattern of the γ3 chain in mouse. We developed three new γ3-reactive antibodies, and we show that the γ3 chain is present in BMs. The distribution pattern is considerably more restricted than that of the γ1 chain and within any tissue there is differential deposition into BM compartments. This is particularly true in the retina and brain, where γ3 is uniquely expressed in a subset of the vascular basement membranes and the pial surface. We used conventional genetic ablation techniques to remove the γ3 chain in mice; unlike other laminin null mice (α5, β2, γ1 nulls), these mice live a normal lifespan and have only minor abnormalities, the most striking of which are ectopic granule cells in the cerebellum and an apparent increase in capillary branching in the outer retina. These data support the suggestion that the γ3 chain is deposited in BMs and contributes some unique properties to their function, particularly in the nervous system.
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Affiliation(s)
- Yong N Li
- Sackler School for Biomedical Sciences, Tufts University School of Medicine, 136 Harrison Avenue, Boston, MA 02111, United States
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Nishimune H. Molecular mechanism of active zone organization at vertebrate neuromuscular junctions. Mol Neurobiol 2011; 45:1-16. [PMID: 22135013 DOI: 10.1007/s12035-011-8216-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Accepted: 10/24/2011] [Indexed: 02/08/2023]
Abstract
Organization of presynaptic active zones is essential for development, plasticity, and pathology of the nervous system. Recent studies indicate a trans-synaptic molecular mechanism that organizes the active zones by connecting the pre- and the postsynaptic specialization. The presynaptic component of this trans-synaptic mechanism is comprised of cytosolic active zone proteins bound to the cytosolic domains of voltage-dependent calcium channels (P/Q-, N-, and L-type) on the presynaptic membrane. The postsynaptic component of this mechanism is the synapse organizer (laminin β2) that is expressed by the postsynaptic cell and accumulates specifically on top of the postsynaptic specialization. The pre- and the postsynaptic components interact directly between the extracellular domains of calcium channels and laminin β2 to anchor the presynaptic protein complex in front of the postsynaptic specialization. Hence, the presynaptic calcium channel functions as a scaffolding protein for active zone organization and as an ion-conducting channel for synaptic transmission. In contrast to the requirement of calcium influx for synaptic transmission, the formation of the active zone does not require the calcium influx through the calcium channels. Importantly, the active zones of adult synapses are not stable structures and require maintenance for their integrity. Furthermore, aging or diseases of the central and peripheral nervous system impair the active zones. This review will focus on the molecular mechanisms that organize the presynaptic active zones and summarize recent findings at the neuromuscular junctions and other synapses.
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Affiliation(s)
- Hiroshi Nishimune
- Department of Anatomy and Cell Biology, and Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical School, 3901 Rainbow Blvd., MS 3051, HLSIC Rm. 2073, Kansas City, KS 66160, USA.
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44
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Miner JH. Glomerular basement membrane composition and the filtration barrier. Pediatr Nephrol 2011; 26:1413-7. [PMID: 21327778 PMCID: PMC3108006 DOI: 10.1007/s00467-011-1785-1] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/20/2011] [Accepted: 01/21/2011] [Indexed: 01/11/2023]
Abstract
The glomerular basement membrane (GBM) is an especially thick basement membrane that contributes importantly to the kidney's filtration barrier. The GBM derives from the fusion of separate podocyte and endothelial cell basement membranes during glomerulogenesis and consists primarily of laminin-521 (α5β2γ1), collagen α3α4α5(IV), nidogens-1 and -2, and agrin. Of these nine proteins, mutations in the genes encoding four of them (LAMB2, COL4A3, COL4A4, and COL4A5) cause glomerular disease in humans as well as in mice. Furthermore, mutation of a fifth (Lama5) gene in podocytes in mice causes proteinuria, nephrotic syndrome, and progression to renal failure. These results highlight the importance of the GBM for establishing and maintaining a properly functioning glomerular filtration barrier.
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Affiliation(s)
- Jeffrey H Miner
- Renal Division, Department of Internal Medicine, School of Medicine, Washington University, 660 S. Euclid Ave., Box 8126, St. Louis, MO 63110, USA.
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45
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Nishimune H. Transsynaptic channelosomes: non-conducting roles of ion channels in synapse formation. Channels (Austin) 2011; 5:432-9. [PMID: 21654201 PMCID: PMC3265764 DOI: 10.4161/chan.5.5.16472] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Revised: 04/14/2011] [Accepted: 04/14/2011] [Indexed: 11/19/2022] Open
Abstract
Recent findings demonstrate that synaptic channels are directly involved in the formation and maintenance of synapses by interacting with synapse organizers. The synaptic channels on the pre- and postsynaptic membranes possess non-conducting roles in addition to their functional roles as ion-conducting channels required for synaptic transmission. For example, presynaptic voltage-dependent calcium channels link the target-derived synapse organizer laminin β2 to cytomatrix of the active zone and function as scaffolding proteins to organize the presynaptic active zones. Furthermore, postsynaptic δ2-type glutamate receptors organize the synapses by forming transsynaptic protein complexes with presynaptic neurexins through synapse organizer cerebellin 1 precursor proteins. Interestingly, the synaptic clustering of AMPA receptors is regulated by neuronal activity-regulated pentraxins, while postsynaptic differentiation is induced by the interaction of postsynaptic calcium channels and thrombospondins. This review will focus on the non-conducting functions of ion-channels that contribute to the synapse formation in concert with synapse organizers and active-zone-specific proteins.
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Affiliation(s)
- Hiroshi Nishimune
- Department of Anatomy and Cell Biology, Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical School, Kansas City, KS, USA.
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Chen YM, Kikkawa Y, Miner JH. A missense LAMB2 mutation causes congenital nephrotic syndrome by impairing laminin secretion. J Am Soc Nephrol 2011; 22:849-58. [PMID: 21511833 DOI: 10.1681/asn.2010060632] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Laminin β2 is a component of laminin-521, which is an important constituent of the glomerular basement membrane (GBM). Null mutations in laminin β2 (LAMB2) cause Pierson syndrome, a severe congenital nephrotic syndrome with ocular and neurologic defects. In contrast, patients with LAMB2 missense mutations, such as R246Q, can have less severe extrarenal defects but still exhibit congenital nephrotic syndrome. To investigate how such missense mutations in LAMB2 cause proteinuria, we generated three transgenic lines of mice in which R246Q-mutant rat laminin β2 replaced the wild-type mouse laminin β2 in the GBM. These transgenic mice developed much less severe proteinuria than their nontransgenic Lamb2-deficient littermates; the level of proteinuria correlated inversely with R246Q-LAMB2 expression. At the onset of proteinuria, expression and localization of proteins associated with the slit diaphragm and foot processes were normal, and there were no obvious ultrastructural abnormalities. Low transgene expressors developed heavy proteinuria, foot process effacement, GBM thickening, and renal failure by 3 months, but high expressors developed only mild proteinuria by 9 months. In vitro studies demonstrated that the R246Q mutation results in impaired secretion of laminin. Taken together, these results suggest that the R246Q mutation causes nephrotic syndrome by impairing secretion of laminin-521 from podocytes into the GBM; however, increased expression of the mutant protein is able to overcome this secretion defect and improve glomerular permselectivity.
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Affiliation(s)
- Ying Maggie Chen
- Renal Division, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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Miner JH. Organogenesis of the kidney glomerulus: focus on the glomerular basement membrane. Organogenesis 2011; 7:75-82. [PMID: 21519194 DOI: 10.4161/org.7.2.15275] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The glomerular basement membrane (GBM) is a crucial component of the kidney's filtration barrier that separates the vasculature from the urinary space. During glomerulogenesis, the GBM is formed from fusion of two distinct basement membranes, one synthesized by the glomerular epithelial cell (podocyte) and the other by the glomerular endothelial cell. The main components of the GBM are laminin-521 (α5β2γ1), collagen α3α4α5(IV), nidogen and the heparan sulfate proteoglycan, agrin. By studying mice lacking specific GBM components, we have shown that during glomerulogenesis, laminin is the only one that is required for GBM integrity and in turn, the GBM is required for completion of glomerulogenesis and glomerular vascularization. In addition, our results from laminin β2-null mice suggest that laminin-521, and thus the GBM, contribute to the establishment and maintenance of the glomerular filtration barrier to plasma albumin. In contrast, mutations that affect GBM collagen IV or agrin do not impair glomerular development or cause immediate leakage of plasma proteins. However, collagen IV mutation, which causes Alport syndrome and ESRD in humans, leads to gradual damage to the GBM that eventually leads to albuminuria and renal failure. These results highlight the importance of the GBM for establishing and maintaining a perfectly functioning, highly selective glomerular filter.
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Affiliation(s)
- Jeffrey H Miner
- Renal Division,Washington University School of Medicine; St. Louis, MO, USA.
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Hirrlinger PG, Pannicke T, Winkler U, Claudepierre T, Varshney S, Schulze C, Reichenbach A, Brunken WJ, Hirrlinger J. Genetic deletion of laminin isoforms β2 and γ3 induces a reduction in Kir4.1 and aquaporin-4 expression and function in the retina. PLoS One 2011; 6:e16106. [PMID: 21283711 PMCID: PMC3025027 DOI: 10.1371/journal.pone.0016106] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Accepted: 12/07/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Glial cells such as retinal Müller glial cells are involved in potassium ion and water homeostasis of the neural tissue. In these cells, inwardly rectifying potassium (Kir) channels and aquaporin-4 water channels play an important role in the process of spatial potassium buffering and water drainage. Moreover, Kir4.1 channels are involved in the maintenance of the negative Müller cell membrane potential. The subcellular distribution of Kir4.1 and aquaporin-4 channels appears to be maintained by interactions with extracellular and intracellular molecules. Laminins in the extracellular matrix, dystroglycan in the membrane, and dystrophins in the cytomatrix form a complex mediating the polarized expression of Kir4.1 and aquaporin-4 in Müller cells. METHODOLOGY/PRINCIPAL FINDINGS The aim of the present study was to test the function of the β2 and γ3 containing laminins in murine Müller cells. We used knockout mice with genetic deletion of both β2 and γ3 laminin genes to assay the effects on Kir4.1 and aquaporin-4. We studied protein and mRNA expression by immunohistochemistry, Western Blot, and quantitative RT-PCR, respectively, and membrane currents of isolated cells by patch-clamp experiments. We found a down-regulation of mRNA and protein of Kir4.1 as well as of aquaporin-4 protein in laminin knockout mice. Moreover, Müller cells from laminin β2 and γ3 knockout mice had reduced Kir-mediated inward currents and their membrane potentials were more positive than those in age-matched wild-type mice. CONCLUSION These findings demonstrate a strong impact of laminin β2 and γ3 subunits on the expression and function of both aquaporin-4 and Kir4.1, two important membrane proteins in Müller cells.
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Affiliation(s)
- Petra G Hirrlinger
- Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany.
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Mohney BG, Pulido JS, Lindor NM, Hogan MC, Consugar MB, Peters J, Pankratz VS, Nasr SH, Smith SJ, Gloor J, Kubly V, Spencer D, Nielson R, Puffenberger EG, Strauss KA, Morton DH, Eldahdah L, Harris PC. A novel mutation of LAMB2 in a multigenerational mennonite family reveals a new phenotypic variant of Pierson syndrome. Ophthalmology 2011; 118:1137-44. [PMID: 21236492 DOI: 10.1016/j.ophtha.2010.10.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2010] [Revised: 09/30/2010] [Accepted: 10/05/2010] [Indexed: 01/15/2023] Open
Abstract
PURPOSE To describe a novel laminin β-2 (LAMB2) mutation associated with nephrotic syndrome and severe retinal disease without microcoria in a large, multigenerational family with Pierson syndrome. DESIGN Retrospective chart review and prospective family examination. PARTICIPANTS An extended consanguineous family of 52 members. METHODS The eyes, urine, and serum DNA were evaluated in all family members after discovering 2 patients, both younger than 10 years, with bilateral retinal detachments and concurrent renal dysfunction. Linkage analysis was performed in the 9 living affected individuals, 7 using the Illumina Human Hap370 Duo Bead Array (Illumina, San Diego, CA) and 2 using GeneChip 10K (Affymetrix, Santa Clara, CA) mapping arrays. MAIN OUTCOME MEASURES The prevalence and severity of ocular and kidney involvement and genetic findings. RESULTS Eleven affected family members were identified (9 living), all manifesting chronic kidney disease and bilateral chorioretinal pigmentary changes, with or without retinal detachments, but without microcoria or neurodevelopmental deficits, segregating in an autosomal recessive pattern. The causative gene was localized to a 9-Mb region on chromosome 3. Comprehensive gene sequencing revealed a novel LAMB2 variant (c.440A → G; His147R) that was homozygous in the 9 living, affected family members, observed at a frequency of 2.1% in the Old Order Mennonite population, and absent in 91 non-Mennonite controls. The mutation is located in a highly conserved site in the N-terminal domain VI of LAMB2. CONCLUSIONS This study describes a novel mutation of LAMB2 and further expands the spectrum of eye and renal manifestations associated with defects in the laminin β-2 chain. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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Affiliation(s)
- Brian G Mohney
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota 55905, USA.
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Hu H, Li J, Zhang Z, Yu M. Pikachurin interaction with dystroglycan is diminished by defective O-mannosyl glycosylation in congenital muscular dystrophy models and rescued by LARGE overexpression. Neurosci Lett 2010; 489:10-5. [PMID: 21129441 DOI: 10.1016/j.neulet.2010.11.056] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Revised: 11/19/2010] [Accepted: 11/19/2010] [Indexed: 11/24/2022]
Abstract
Congenital muscular dystrophies (CMD) such as muscle-eye-brain disease caused by defective glycosylation of α-dystroglycan (α-DG) exhibit defective photoreceptor synaptic function. Mouse knockouts of dystroglycan and its extracellular matrix binding partner pikachurin recapitulate this phenotype. In this study, pikachurin-α-dystroglycan interactions in several mouse models of CMD were examined by pikachurin overlay experiments. The results show that hypoglycosylation of α-dystroglycan resulted in markedly reduced pikachurin-α-dystroglycan interactions. Expression of pikachurin is abolished at the outer plexiform layer of two mouse models, protein O-mannose N-acetylglucosaminyl transferase 1 (POMGnT1) knockout and Large(myd) mice. Overexpressing LARGE restored this interaction in POMGnT1 knockout cells. These results indicate that pikachurin interactions with α-dystroglycan and its localization at the photoreceptor ribbon synapse require normal glycosylation of α-dystroglycan.
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Affiliation(s)
- Huaiyu Hu
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, United States.
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