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Hyde LF, Kong Y, Zhao L, Rao SR, Wang J, Stone L, Njaa A, Collin GB, Krebs MP, Chang B, Fliesler SJ, Nishina PM, Naggert JK. A Dpagt1 Missense Variant Causes Degenerative Retinopathy without Myasthenic Syndrome in Mice. Int J Mol Sci 2022; 23:ijms231912005. [PMID: 36233305 PMCID: PMC9570038 DOI: 10.3390/ijms231912005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 09/29/2022] [Accepted: 10/04/2022] [Indexed: 01/12/2023] Open
Abstract
Congenital disorders of glycosylation (CDG) are a heterogenous group of primarily autosomal recessive mendelian diseases caused by disruptions in the synthesis of lipid-linked oligosaccharides and their transfer to proteins. CDGs usually affect multiple organ systems and vary in presentation, even within families. There is currently no cure, and treatment is aimed at ameliorating symptoms and improving quality of life. Here, we describe a chemically induced mouse mutant, tvrm76, with early-onset photoreceptor degeneration. The recessive mutation was mapped to Chromosome 9 and associated with a missense mutation in the Dpagt1 gene encoding UDP-N-acetyl-D-glucosamine:dolichyl-phosphate N-acetyl-D-glucosaminephosphotransferase (EC 2.7.8.15). The mutation is predicted to cause a substitution of aspartic acid with glycine at residue 166 of DPAGT1. This represents the first viable animal model of a Dpagt1 mutation and a novel phenotype for a CDG. The increased expression of Ddit3, and elevated levels of HSPA5 (BiP) suggest the presence of early-onset endoplasmic reticulum (ER) stress. These changes were associated with the induction of photoreceptor apoptosis in tvrm76 retinas. Mutations in human DPAGT1 cause myasthenic syndrome-13 and severe forms of a congenital disorder of glycosylation Type Ij. In contrast, Dpagt1tvrm76 homozygous mice present with congenital photoreceptor degeneration without overt muscle or muscular junction involvement. Our results suggest the possibility of DPAGT1 mutations in human patients that present primarily with retinitis pigmentosa, with little or no muscle disease. Variants in DPAGT1 should be considered when evaluating cases of non-syndromic retinal degeneration.
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Affiliation(s)
| | - Yang Kong
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- The Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME 04469, USA
| | - Lihong Zhao
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Sriganesh Ramachandra Rao
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14203, USA
- Research Service, VA Western New York Healthcare System, Buffalo, NY 14215, USA
| | - Jieping Wang
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Andrew Njaa
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | | | | | - Bo Chang
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Steven J. Fliesler
- Departments of Ophthalmology and Biochemistry and Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, NY 14203, USA
- Research Service, VA Western New York Healthcare System, Buffalo, NY 14215, USA
| | | | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
- Correspondence: ; Tel.: +1-207-288-6382
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Pandey RS, Krebs MP, Bolisetty MT, Charette JR, Naggert JK, Robson P, Nishina PM, Carter GW. Single-Cell RNA Sequencing Reveals Molecular Features of Heterogeneity in the Murine Retinal Pigment Epithelium. Int J Mol Sci 2022; 23:ijms231810419. [PMID: 36142331 PMCID: PMC9499471 DOI: 10.3390/ijms231810419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2022] [Revised: 08/09/2022] [Accepted: 09/05/2022] [Indexed: 11/16/2022] Open
Abstract
Transcriptomic analysis of the mammalian retinal pigment epithelium (RPE) aims to identify cellular networks that influence ocular development, maintenance, function, and disease. However, available evidence points to RPE cell heterogeneity within native tissue, which adds complexity to global transcriptomic analysis. Here, to assess cell heterogeneity, we performed single-cell RNA sequencing of RPE cells from two young adult male C57BL/6J mice. Following quality control to ensure robust transcript identification limited to cell singlets, we detected 13,858 transcripts among 2667 and 2846 RPE cells. Dimensional reduction by principal component analysis and uniform manifold approximation and projection revealed six distinct cell populations. All clusters expressed transcripts typical of RPE cells; the smallest (C1, containing 1–2% of total cells) exhibited the hallmarks of stem and/or progenitor (SP) cells. Placing C1–6 along a pseudotime axis suggested a relative decrease in melanogenesis and SP gene expression and a corresponding increase in visual cycle gene expression upon RPE maturation. K-means clustering of all detected transcripts identified additional expression patterns that may advance the understanding of RPE SP cell maintenance and the evolution of cellular metabolic networks during development. This work provides new insights into the transcriptome of the mouse RPE and a baseline for identifying experimentally induced transcriptional changes in future studies of this tissue.
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Affiliation(s)
- Ravi S. Pandey
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Dr., Farmington, CT 06032, USA
| | - Mark P. Krebs
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Mohan T. Bolisetty
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Dr., Farmington, CT 06032, USA
| | | | | | - Paul Robson
- The Jackson Laboratory for Genomic Medicine, 10 Discovery Dr., Farmington, CT 06032, USA
| | - Patsy M. Nishina
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
- Correspondence: (P.M.N.); (G.W.C.)
| | - Gregory W. Carter
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
- Correspondence: (P.M.N.); (G.W.C.)
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Weatherly SM, Collin GB, Charette JR, Stone L, Damkham N, Hyde LF, Peterson JG, Hicks W, Carter GW, Naggert JK, Krebs MP, Nishina PM. Identification of Arhgef12 and Prkci as genetic modifiers of retinal dysplasia in the Crb1rd8 mouse model. PLoS Genet 2022; 18:e1009798. [PMID: 35675330 PMCID: PMC9212170 DOI: 10.1371/journal.pgen.1009798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Revised: 06/21/2022] [Accepted: 05/03/2022] [Indexed: 12/03/2022] Open
Abstract
Mutations in the apicobasal polarity gene CRB1 lead to diverse retinal diseases, such as Leber congenital amaurosis, cone-rod dystrophy, retinitis pigmentosa (with and without Coats-like vasculopathy), foveal retinoschisis, macular dystrophy, and pigmented paravenous chorioretinal atrophy. Limited correlation between disease phenotypes and CRB1 alleles, and evidence that patients sharing the same alleles often present with different disease features, suggest that genetic modifiers contribute to clinical variation. Similarly, the retinal phenotype of mice bearing the Crb1 retinal degeneration 8 (rd8) allele varies with genetic background. Here, we initiated a sensitized chemical mutagenesis screen in B6.Cg-Crb1rd8/Pjn, a strain with a mild clinical presentation, to identify genetic modifiers that cause a more severe disease phenotype. Two models from this screen, Tvrm266 and Tvrm323, exhibited increased retinal dysplasia. Genetic mapping with high-throughput exome and candidate-gene sequencing identified causative mutations in Arhgef12 and Prkci, respectively. Epistasis analysis of both strains indicated that the increased dysplastic phenotype required homozygosity of the Crb1rd8 allele. Retinal dysplastic lesions in Tvrm266 mice were smaller and caused less photoreceptor degeneration than those in Tvrm323 mice, which developed an early, large diffuse lesion phenotype. At one month of age, Müller glia and microglia mislocalization at dysplastic lesions in both modifier strains was similar to that in B6.Cg-Crb1rd8/Pjn mice but photoreceptor cell mislocalization was more extensive. External limiting membrane disruption was comparable in Tvrm266 and B6.Cg-Crb1rd8/Pjn mice but milder in Tvrm323 mice. Immunohistological analysis of mice at postnatal day 0 indicated a normal distribution of mitotic cells in Tvrm266 and Tvrm323 mice, suggesting normal early development. Aberrant electroretinography responses were observed in both models but functional decline was significant only in Tvrm323 mice. These results identify Arhgef12 and Prkci as modifier genes that differentially shape Crb1-associated retinal disease, which may be relevant to understanding clinical variability and underlying disease mechanisms in humans. Inherited eye diseases affect roughly 1:1,000 individuals worldwide. Although these diseases are often linked to variants of a single gene, it is increasingly recognized that a second variant in other genes may modify disease characteristics, including age of onset, severity, and lesion appearance. Identifying such modifier genes in humans is difficult. In this study, two modifiers of a gene associated with retinal damage leading to childhood blindness in humans (CRB1) were identified in mice. Retinal damage caused by Crb1 mutation alone was less severe than in the presence of Arhgef12 or Prkci mutations. Furthermore, the modifier gene mutations caused retinal damage only in the presence of the Crb1 mutation. Our results point to a role of mouse Crb1 and the modifying effects of Arhgef12 and Prkci in a biological network that controls adhesive interactions between cells. The variation in disease severity, lesion appearance, and visual responses in these mice provide a dramatic example of modifier gene influence. This work may lead to an improved understanding of the molecular basis of CRB1-associated retinal disease, with possible relevance to diagnostic and therapeutic intervention in humans.
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Affiliation(s)
| | - Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Nattaya Damkham
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- Graduate Program in Immunology, Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Lillian F. Hyde
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - Wanda Hicks
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | | | - Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- * E-mail: (MPK); (PMN)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- * E-mail: (MPK); (PMN)
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Ji X, Zhao L, Umapathy A, Fitzmaurice B, Wang J, Williams DS, Chang B, Naggert JK, Nishina PM. Deficiency in Lyst function leads to accumulation of secreted proteases and reduced retinal adhesion. PLoS One 2022; 17:e0254469. [PMID: 35239671 PMCID: PMC8893605 DOI: 10.1371/journal.pone.0254469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 02/18/2022] [Indexed: 11/19/2022] Open
Abstract
Chediak–Higashi syndrome, caused by mutations in the Lysosome Trafficking Regulator (Lyst) gene, is a recessive hypopigmentation disorder characterized by albinism, neuropathies, neurodegeneration, and defective immune responses, with enlargement of lysosomes and lysosome-related organelles. Although recent studies have suggested that Lyst mutations impair the regulation of sizes of lysosome and lysosome-related organelle, the underlying pathogenic mechanism of Chediak–Higashi syndrome is still unclear. Here we show striking evidence that deficiency in LYST protein function leads to accumulation of photoreceptor outer segment phagosomes in retinal pigment epithelial cells, and reduces adhesion between photoreceptor outer segment and retinal pigment epithelial cells in a mouse model of Chediak–Higashi syndrome. In addition, we observe elevated levels of cathepsins, matrix metallopeptidase (MMP) 3 and oxidative stress markers in the retinal pigment epithelium of Lyst mutants. Previous reports showed that impaired degradation of photoreceptor outer segment phagosomes causes elevated oxidative stress, which could consequently lead to increases of cysteine cathepsins and MMPs in the extracellular matrix. Taken together, we conclude that the loss of LYST function causes accumulation of phagosomes in the retinal pigment epithelium and elevation of several extracellular matrix-remodeling proteases through oxidative stress, which may, in turn, reduce retinal adhesion. Our work reveals previously unreported pathogenic events in the retinal pigment epithelium caused by Lyst deficiency. The same pathogenic events may be conserved in other professional phagocytic cells, such as macrophages in the immune system, contributing to overall Chediak–Higashi syndrome pathology.
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Affiliation(s)
- Xiaojie Ji
- The Jackson Laboratory, Bar Harbor, ME, United States of America
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, United States of America
| | - Lihong Zhao
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | - Ankita Umapathy
- Department of Ophthalmology and Stein Eye Institute, University of California, Los Angeles, CA, United States of America
| | | | - Jieping Wang
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | - David S. Williams
- Department of Ophthalmology and Stein Eye Institute, University of California, Los Angeles, CA, United States of America
- Department of Neurobiology, David Geffen School of Medicine, UCLA, Los Angeles, CA, United States of America
- Molecular Biology Institute, UCLA, Los Angeles, CA, United States of America
- Brain Research Institute, UCLA, Los Angeles, CA, United States of America
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, ME, United States of America
| | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, ME, United States of America
- * E-mail: (JKN); (PMN)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, ME, United States of America
- * E-mail: (JKN); (PMN)
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Collin GB, Shi L, Yu M, Akturk N, Charette JR, Hyde LF, Weatherly SM, Pera MF, Naggert JK, Peachey NS, Nishina PM, Krebs MP. A Splicing Mutation in Slc4a5 Results in Retinal Detachment and Retinal Pigment Epithelium Dysfunction. Int J Mol Sci 2022; 23:ijms23042220. [PMID: 35216333 PMCID: PMC8875008 DOI: 10.3390/ijms23042220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 02/13/2022] [Accepted: 02/14/2022] [Indexed: 12/29/2022] Open
Abstract
Fluid and solute transporters of the retinal pigment epithelium (RPE) are core components of the outer blood–retinal barrier. Characterizing these transporters and their role in retinal homeostasis may provide insights into ocular function and disease. Here, we describe RPE defects in tvrm77 mice, which exhibit hypopigmented patches in the central retina. Mapping and nucleotide sequencing of tvrm77 mice revealed a disrupted 5’ splice donor sequence in Slc4a5, a sodium bicarbonate cotransporter gene. Slc4a5 expression was reduced 19.7-fold in tvrm77 RPE relative to controls, and alternative splice variants were detected. SLC4A5 was localized to the Golgi apparatus of cultured human RPE cells and in apical and basal membranes. Fundus imaging, optical coherence tomography, microscopy, and electroretinography (ERG) of tvrm77 mice revealed retinal detachment, hypopigmented patches corresponding to neovascular lesions, and retinal folds. Detachment worsened and outer nuclear layer thickness decreased with age. ERG a- and b-wave response amplitudes were initially normal but declined in older mice. The direct current ERG fast oscillation and light peak were reduced in amplitude at all ages, whereas other RPE-associated responses were unaffected. These results link a new Slc4a5 mutation to subretinal fluid accumulation and altered light-evoked RPE electrophysiological responses, suggesting that SLC4A5 functions at the outer blood–retinal barrier.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Lanying Shi
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA; (M.Y.); (N.S.P.)
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - Nurten Akturk
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Jeremy R. Charette
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Lillian F. Hyde
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Sonia M. Weatherly
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Martin F. Pera
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Jürgen K. Naggert
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
| | - Neal S. Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, OH 44195, USA; (M.Y.); (N.S.P.)
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, 9500 Euclid Avenue, Cleveland, OH 44195, USA
- Research Service, Louis Stokes Cleveland VA Medical Center, 10701 East Boulevard, Cleveland, OH 44106, USA
| | - Patsy M. Nishina
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.)
| | - Mark P. Krebs
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA; (G.B.C.); (L.S.); (N.A.); (J.R.C.); (L.F.H.); (S.M.W.); (M.F.P.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.)
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Collin GB, Gogna N, Chang B, Damkham N, Pinkney J, Hyde LF, Stone L, Naggert JK, Nishina PM, Krebs MP. Mouse Models of Inherited Retinal Degeneration with Photoreceptor Cell Loss. Cells 2020; 9:cells9040931. [PMID: 32290105 PMCID: PMC7227028 DOI: 10.3390/cells9040931] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degeneration (RD) leads to the impairment or loss of vision in millions of individuals worldwide, most frequently due to the loss of photoreceptor (PR) cells. Animal models, particularly the laboratory mouse, have been used to understand the pathogenic mechanisms that underlie PR cell loss and to explore therapies that may prevent, delay, or reverse RD. Here, we reviewed entries in the Mouse Genome Informatics and PubMed databases to compile a comprehensive list of monogenic mouse models in which PR cell loss is demonstrated. The progression of PR cell loss with postnatal age was documented in mutant alleles of genes grouped by biological function. As anticipated, a wide range in the onset and rate of cell loss was observed among the reported models. The analysis underscored relationships between RD genes and ciliary function, transcription-coupled DNA damage repair, and cellular chloride homeostasis. Comparing the mouse gene list to human RD genes identified in the RetNet database revealed that mouse models are available for 40% of the known human diseases, suggesting opportunities for future research. This work may provide insight into the molecular players and pathways through which PR degenerative disease occurs and may be useful for planning translational studies.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Navdeep Gogna
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Nattaya Damkham
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jai Pinkney
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lillian F. Hyde
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
| | - Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
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Collin GB, Won J, Krebs MP, Hicks WJ, Charette JR, Naggert JK, Nishina PM. Disruption in murine Eml1 perturbs retinal lamination during early development. Sci Rep 2020; 10:5647. [PMID: 32221352 PMCID: PMC7101416 DOI: 10.1038/s41598-020-62373-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/09/2020] [Indexed: 11/23/2022] Open
Abstract
During mammalian development, establishing functional neural networks in stratified tissues of the mammalian central nervous system depends upon the proper migration and positioning of neurons, a process known as lamination. In particular, the pseudostratified neuroepithelia of the retina and cerebrocortical ventricular zones provide a platform for progenitor cell proliferation and migration. Lamination defects in these tissues lead to mispositioned neurons, disrupted neuronal connections, and abnormal function. The molecular mechanisms necessary for proper lamination in these tissues are incompletely understood. Here, we identified a nonsense mutation in the Eml1 gene in a novel murine model, tvrm360, displaying subcortical heterotopia, hydrocephalus and disorganization of retinal architecture. In the retina, Eml1 disruption caused abnormal positioning of photoreceptor cell nuclei early in development. Upon maturation, these ectopic photoreceptors possessed cilia and formed synapses but failed to produce robust outer segments, implying a late defect in photoreceptor differentiation secondary to mislocalization. In addition, abnormal positioning of Müller cell bodies and bipolar cells was evident throughout the inner neuroblastic layer. Basal displacement of mitotic nuclei in the retinal neuroepithelium was observed in tvrm360 mice at postnatal day 0. The abnormal positioning of retinal progenitor cells at birth and ectopic presence of photoreceptors and secondary neurons upon maturation suggest that EML1 functions early in eye development and is crucial for proper retinal lamination during cellular proliferation and development.
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Affiliation(s)
- G B Collin
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, 04609, USA
| | - J Won
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, 04609, USA
| | - M P Krebs
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, 04609, USA
| | - W J Hicks
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, 04609, USA
| | - J R Charette
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, 04609, USA
| | - J K Naggert
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, 04609, USA
| | - P M Nishina
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine, 04609, USA.
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Kong Y, Zhao L, Charette JR, Hicks WL, Stone L, Nishina PM, Naggert JK. An FRMD4B variant suppresses dysplastic photoreceptor lesions in models of enhanced S-cone syndrome and of Nrl deficiency. Hum Mol Genet 2019; 27:3340-3352. [PMID: 29947801 DOI: 10.1093/hmg/ddy238] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 06/04/2018] [Indexed: 12/16/2022] Open
Abstract
Photoreceptor dysplasia, characterized by formation of folds and (pseudo-)rosettes in the outer retina, is associated with loss of functional nuclear receptor subfamily 2 group E member 3 (NR2E3) and neural retina leucine-zipper (NRL) in both humans and mice. A sensitized chemical mutagenesis study to identify genetic modifiers that suppress photoreceptor dysplasia in Nr2e3rd7mutant mice identified line Tvrm222, which exhibits a normal fundus appearance in the presence of the rd7 mutation. The Tvrm222 modifier of Nr2e3rd7/rd7 was localized to Chromosome 6 and identified as a missense mutation in the FERM domain containing 4B (Frmd4b) gene. The variant is predicted to cause the substitution of a serine residue 938 with proline (S938P). The Frmd4bTvrm222 allele was also found to suppress outer nuclear layer (ONL) rosettes in Nrl-/- mice. Fragmentation of the external limiting membrane (ELM), normally observed in rd7 and Nrl-/-mouse retinas, was absent in the presence of the Frmd4bTvrm222 allele. FRMD4B, a binding partner of cytohesin 3, is proposed to participate in cell junction remodeling. Its biological function in photoreceptor dysplasia has not been previously examined. In vitro experiments showed that the FRMD4B938P variant fails to be efficiently recruited to the cell surface upon insulin stimulation. In addition, we found a reduction in protein kinase B phosphorylation and increased levels of cell junction proteins, Catenin beta 1 and tight junction protein 1, associated with the cell membrane in Tvrm222 retinas. Taken together, this study reveals a critical role of FRMD4B in maintaining ELM integrity and in rescuing morphological abnormalities of the ONL in photoreceptor dysplasia.
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Affiliation(s)
- Yang Kong
- Jackson Laboratory, Bar Harbor, ME, USA.,Graduate School of Biomedical Science and Engineering, University of Maine, Orono, ME, USA
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9
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Jaykumar AB, Caceres PS, King-Medina KN, Liao TD, Datta I, Maskey D, Naggert JK, Mendez M, Beierwaltes WH, Ortiz PA. Role of Alström syndrome 1 in the regulation of blood pressure and renal function. JCI Insight 2018; 3:95076. [PMID: 30385718 DOI: 10.1172/jci.insight.95076] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 09/26/2018] [Indexed: 01/22/2023] Open
Abstract
Elevated blood pressure (BP) and renal dysfunction are complex traits representing major global health problems. Single nucleotide polymorphisms identified by genome-wide association studies have identified the Alström syndrome 1 (ALMS1) gene locus to render susceptibility for renal dysfunction, hypertension, and chronic kidney disease (CKD). Mutations in the ALMS1 gene in humans causes Alström syndrome, characterized by progressive metabolic alterations including hypertension and CKD. Despite compelling genetic evidence, the underlying biological mechanism by which mutations in the ALMS1 gene lead to the above-mentioned pathophysiology is not understood. We modeled this effect in a KO rat model and showed that ALMS1 genetic deletion leads to hypertension. We demonstrate that the link between ALMS1 and hypertension involves the activation of the renal Na+/K+/2Cl- cotransporter NKCC2, mediated by regulation of its endocytosis. Our findings establish a link between the genetic susceptibility to hypertension, CKD, and the expression of ALMS1 through its role in a salt-reabsorbing tubular segment of the kidney. These data point to ALMS1 as a potentially novel gene involved in BP and renal function regulation.
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Affiliation(s)
- Ankita Bachhawat Jaykumar
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Paulo S Caceres
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Keyona N King-Medina
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Tang-Dong Liao
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA
| | - Indrani Datta
- Department of Public Health Sciences and.,Center for Bioinformatics, Henry Ford Health System, Detroit, Michigan, USA
| | - Dipak Maskey
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA
| | | | - Mariela Mendez
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA
| | - William H Beierwaltes
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Pablo A Ortiz
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA.,Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
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10
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Waldman M, Han JC, Reyes-Capo DP, Bryant J, Carson KA, Turkbey B, Choyke P, Naggert JK, Gahl WA, Marshall JD, Gunay-Aygun M. Alström syndrome: Renal findings in correlation with obesity, insulin resistance, dyslipidemia and cardiomyopathy in 38 patients prospectively evaluated at the NIH clinical center. Mol Genet Metab 2018; 125:181-191. [PMID: 30064963 PMCID: PMC7984722 DOI: 10.1016/j.ymgme.2018.07.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Revised: 07/19/2018] [Accepted: 07/19/2018] [Indexed: 12/15/2022]
Abstract
Alström Syndrome is a ciliopathy associated with obesity, insulin resistance/type 2 diabetes mellitus, cardiomyopathy, retinal degeneration, hearing loss, progressive liver and kidney disease, and normal cognitive function. ALMS1, the protein defective in this disorder, localizes to the cytoskeleton, microtubule organizing center, as well as the centrosomes and ciliary basal bodies and plays roles in formation and maintenance of cilia, cell cycle regulation, and endosomal trafficking. Kidney disease in this disorder has not been well characterized. We performed comprehensive multisystem evaluations on 38 patients. Kidney function decreased progressively; eGFR varied inversely with age (p = 0.002). Eighteen percent met the definition for chronic kidney disease (eGFR < 60 mL/min/1.73 m2 and proteinuria); all were adults with median age of 32.8 (20.6-37.9) years. After adjusting for age, there were no significant associations of kidney dysfunction with type 2 diabetes mellitus, dyslipidemia, hypertension, cardiomyopathy or portal hypertension suggesting that kidney disease in AS is a primary manifestation of the syndrome due to lack of ALMS1 protein. Approximately one-third of patients had hyperechogenicity of the renal parenchyma on imaging. While strict control of type 2 diabetes mellitus may decrease kidney-related morbidity and mortality in Alström syndrome, identification of novel targeted therapies is needed.
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Affiliation(s)
- Meryl Waldman
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Joan C Han
- Unit on Metabolism and Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States; Section on Growth and Obesity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States; Departments of Pediatrics and Physiology, University of Tennessee Health Science Center, Le Bonheur Children's Foundation Research Institute, Memphis, TN, United States
| | - Daniela P Reyes-Capo
- Unit on Metabolism and Neuroendocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, United States
| | - Joy Bryant
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States
| | - Kathryn A Carson
- Department of Epidemiology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA; Division of General Internal Medicine, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Baris Turkbey
- Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | - Peter Choyke
- Molecular Imaging Program, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States
| | | | - William A Gahl
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda 20892, MD, United States
| | | | - Meral Gunay-Aygun
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, United States; Johns Hopkins University School of Medicine, Department of Pediatrics and McKusick-Nathans Institute of Genetic Medicine, Baltimore, MD, United States.
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11
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Han JC, Reyes-Capo DP, Liu CY, Reynolds JC, Turkbey E, Turkbey IB, Bryant J, Marshall JD, Naggert JK, Gahl WA, Yanovski JA, Gunay-Aygun M. Comprehensive Endocrine-Metabolic Evaluation of Patients With Alström Syndrome Compared With BMI-Matched Controls. J Clin Endocrinol Metab 2018; 103:2707-2719. [PMID: 29718281 PMCID: PMC6276679 DOI: 10.1210/jc.2018-00496] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 04/24/2018] [Indexed: 12/12/2022]
Abstract
BACKGROUND Alström syndrome (AS), a monogenic form of obesity, is caused by recessive mutations in the centrosome- and basal body-associated gene ALMS1. AS is characterized by retinal dystrophy, sensory hearing loss, cardiomyopathy, childhood obesity, and metabolic derangements. OBJECTIVE We sought to characterize the endocrine and metabolic features of AS while accounting for obesity as a confounder by comparing patients with AS to body mass index (BMI)-matched controls. METHODS We evaluated 38 patients with AS (age 2 to 38 years) who were matched with 76 controls (age 2 to 48 years) by age, sex, race, and BMI. Fasting biochemistries, mixed meal test (MMT), indirect calorimetry, dual-energy X-ray absorptiometry, and MRI/magnetic resonance spectroscopy were performed. RESULTS Frequent abnormalities in AS included 76% obesity, 37% type 2 diabetes mellitus (T2DM), 29% hypothyroidism (one-third central, two-thirds primary), 3% central adrenal insufficiency, 57% adult hypogonadism (one-third central, two-thirds primary), and 25% female hyperandrogenism. Patients with AS and controls had similar BMI z scores, body fat, waist circumference, abdominal visceral fat, muscle fat, resting energy expenditure (adjusted for lean mass), free fatty acids, glucagon, prolactin, ACTH, and cortisol. Compared with controls, patients with AS were shorter and had lower IGF-1 concentrations (Ps ≤ 0.001). Patients with AS had significantly greater fasting and MMT insulin resistance indices, higher MMT glucose, insulin, and C-peptide values, higher HbA1c, and higher prevalence of T2DM (Ps < 0.001). Patients with AS had significantly higher triglycerides, lower high-density lipoprotein cholesterol, and a 10-fold greater prevalence of metabolic syndrome (Ps < 0.001). Patients with AS demonstrated significantly greater liver triglyceride accumulation and higher transaminases (P < 0.001). CONCLUSION Severe insulin resistance and T2DM are the hallmarks of AS. However, patients with AS may present with multiple other endocrinopathies affecting growth and development.
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Affiliation(s)
- Joan C Han
- Unit on Metabolism and Neuroendocrinology, Eunice Kennedy Shriver National
Institute of Child Health and Human Development, National Institutes of Health, Bethesda,
Maryland
- Section on Growth and Obesity, Eunice Kennedy Shriver National Institute of
Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
- Departments of Pediatrics and Physiology, University of Tennessee Health
Science Center and Le Bonheur Children’s Foundation Research Institute, Memphis,
Tennessee
- Correspondence and Reprint Requests: Joan C. Han, MD, Departments of Pediatrics and Physiology, University of Tennessee
Health Science Center and Le Bonheur Children’s Foundation Research Institute, 50 North
Dunlap Street, Room 454R, Memphis, Tennessee 38103. E-mail:
| | - Daniela P Reyes-Capo
- Unit on Metabolism and Neuroendocrinology, Eunice Kennedy Shriver National
Institute of Child Health and Human Development, National Institutes of Health, Bethesda,
Maryland
| | - Chia-Ying Liu
- Radiology and Imaging Sciences, National Institutes of Health Clinical Research
Center, Bethesda, Maryland
| | - James C Reynolds
- Radiology and Imaging Sciences, National Institutes of Health Clinical Research
Center, Bethesda, Maryland
| | - Evrim Turkbey
- Radiology and Imaging Sciences, National Institutes of Health Clinical Research
Center, Bethesda, Maryland
| | - Ismail Baris Turkbey
- Center for Cancer Research, National Cancer Institute, National Institutes of
Health, Bethesda, Maryland
| | - Joy Bryant
- Human Biochemical Genetics Section, Medical Genetics Branch, National Human
Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | | | | | - William A Gahl
- Human Biochemical Genetics Section, Medical Genetics Branch, National Human
Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Jack A Yanovski
- Section on Growth and Obesity, Eunice Kennedy Shriver National Institute of
Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Meral Gunay-Aygun
- Human Biochemical Genetics Section, Medical Genetics Branch, National Human
Genome Research Institute, National Institutes of Health, Bethesda, Maryland
- The McKusick-Nathans Institute of Genetic Medicine, Department of Pediatrics,
Johns Hopkins School of Medicine, Baltimore, Maryland
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12
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Kong Y, Naggert JK, Nishina PM. The Impact of Adherens and Tight Junctions on Physiological Function and Pathological Changes in the Retina. Retinal Degenerative Diseases 2018; 1074:545-551. [DOI: 10.1007/978-3-319-75402-4_66] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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13
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Krebs MP, Collin GB, Hicks WL, Yu M, Charette JR, Shi LY, Wang J, Naggert JK, Peachey NS, Nishina PM. Mouse models of human ocular disease for translational research. PLoS One 2017; 12:e0183837. [PMID: 28859131 PMCID: PMC5578669 DOI: 10.1371/journal.pone.0183837] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 08/12/2017] [Indexed: 01/24/2023] Open
Abstract
Mouse models provide a valuable tool for exploring pathogenic mechanisms underlying inherited human disease. Here, we describe seven mouse models identified through the Translational Vision Research Models (TVRM) program, each carrying a new allele of a gene previously linked to retinal developmental and/or degenerative disease. The mutations include four alleles of three genes linked to human nonsyndromic ocular diseases (Aipl1tvrm119, Aipl1tvrm127, Rpgrip1tvrm111, RhoTvrm334) and three alleles of genes associated with human syndromic diseases that exhibit ocular phentoypes (Alms1tvrm102, Clcn2nmf289, Fkrptvrm53). Phenotypic characterization of each model is provided in the context of existing literature, in some cases refining our current understanding of specific disease attributes. These murine models, on fixed genetic backgrounds, are available for distribution upon request and may be useful for understanding the function of the gene in the retina, the pathological mechanisms induced by its disruption, and for testing experimental approaches to treat the corresponding human ocular diseases.
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Affiliation(s)
- Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Wanda L. Hicks
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Minzhong Yu
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States of America
| | | | - Lan Ying Shi
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Jieping Wang
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - Neal S. Peachey
- Department of Ophthalmic Research, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, United States of America
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, Ohio, United States of America
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio, United States of America
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
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14
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Lindsey S, Brewer C, Stakhovskaya O, Kim HJ, Zalewski C, Bryant J, King KA, Naggert JK, Gahl WA, Marshall JD, Gunay-Aygun M. Auditory and otologic profile of Alström syndrome: Comprehensive single center data on 38 patients. Am J Med Genet A 2017; 173:2210-2218. [PMID: 28573831 PMCID: PMC5526054 DOI: 10.1002/ajmg.a.38316] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 04/19/2017] [Accepted: 05/16/2017] [Indexed: 12/17/2022]
Abstract
Alström syndrome (AS) is a rare autosomal recessive ciliopathy caused by mutations in the ALMS1 gene. Hallmark characteristics include childhood onset of severe retinal degeneration, sensorineural hearing loss, obesity, insulin-resistant diabetes, and cardiomyopathy. Here we comprehensively characterize the auditory and otologic manifestations in a prospective case series of 38 individuals, aged 1.7-37.9 years, with genetically confirmed AS. Hearing loss was preceded by retinal dystrophy in all cases, and had an average age of detection of 7.45 years (range 1.5-15). Audiometric assessments showed mean pure tone averages (0.5, 1, 2, 4 kHz) of 48.6 and 47.5 dB HL in the right and left ears, respectively. Hearing was within normal limits for only 8/74 ears (11%). For the 66 ears with hearing loss, the degree was mild (12%), moderate (54%), or severe (8%). Type of hearing loss was predominantly sensorineural (77%), while three ears had mixed loss, no ears had conductive loss, and type of hearing loss was indeterminate for the remaining 12 ears. Serial audiograms available for 33 patients showed hearing loss progression of approximately 10-15 dB/decade. Our data show that hearing loss associated with AS begins in childhood and is a predominantly symmetric, sensory hearing loss that may progress to a severe degree. Absent otoacoustic emissions, intact speech discrimination, and disproportionately normal auditory brainstem responses suggest an outer hair cell site of lesion. These findings indicate that individuals with AS would benefit from sound amplification and if necessary, cochlear implantation.
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Affiliation(s)
- Spencer Lindsey
- Department of Otolaryngology-Head and Neck Surgery, Georgetown University Hospital, Washington, D.C
| | - Carmen Brewer
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland
| | - Olga Stakhovskaya
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland
| | - Hung Jeffrey Kim
- Department of Otolaryngology-Head and Neck Surgery, Georgetown University Hospital, Washington, D.C
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland
| | - Chris Zalewski
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland
| | - Joy Bryant
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Kelly A King
- Otolaryngology Branch, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland
| | | | - William A Gahl
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
- NIH Undiagnosed Diseases Program, Common Fund, Office of the Director, National Institutes of Health, Bethesda, Maryland
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
| | - Jan D Marshall
- The Jackson Laboratory, Bar Harbor, Maine
- Alström Syndrome International, Bar Harbor, Maine
| | - Meral Gunay-Aygun
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland
- Johns Hopkins University School of Medicine, Department of Pediatrics and McKusick-Nathans Institute of Genetic Medicine, Baltimore, Maryland
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15
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Brofferio A, Sachdev V, Hannoush H, Marshall JD, Naggert JK, Sidenko S, Noreuil A, Sirajuddin A, Bryant J, Han JC, Arai AE, Gahl WA, Gunay-Aygun M. Characteristics of cardiomyopathy in Alström syndrome: Prospective single-center data on 38 patients. Mol Genet Metab 2017; 121:336-343. [PMID: 28610912 PMCID: PMC5555226 DOI: 10.1016/j.ymgme.2017.05.017] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 05/26/2017] [Accepted: 05/27/2017] [Indexed: 01/01/2023]
Abstract
BACKGROUND Alström syndrome (AS) is a rare monogenetic disorder with multi-organ involvement. Complex metabolic disturbances are common and cardiomyopathy is a well-recognized feature in infants as well as in older children and adults. Although the mechanism of cardiomyopathy is not known, previous reports suggest that individuals with infantile-onset cardiac disease recover completely. METHODS In this single center prospective series of 38 children and adults (age range 1.7 to 37.9years; 20 females) with AS, we evaluated cardiac manifestations in detail, in the context of specific ALMS1 mutations and multisystem involvement. All patients underwent ALMS1 sequencing, biochemical testing, electrocardiogram, and echocardiographic imaging with speckle tracking to evaluate systolic strain; 21 patients underwent cardiac magnetic resonance imaging with T1 mapping. RESULTS Approximately half of patients (17/38) had a previous diagnosis of cardiomyopathy. Global longitudinal strain, a measure of systolic contractile function, was abnormal in 94% of patients and correlated with body mass index (r=0.602, p=0.002) and C-reactive protein level (r=0.56, p=0.004), but only in children. Electrocardiographic abnormalities were seen in two-thirds of patients, and left ventricular dilatation and/or dysfunction was present in 4 adults and 4 children. CONCLUSION AS patients with a history of resolved infantile cardiomyopathy continue to have residual impairment in cardiac function. For patients with a normal ejection fraction and no prior cardiac history, strain can be abnormal, suggesting subclinical cardiac involvement. Close cardiac screening and aggressive modification of other manifestations of AS that are risk factors for cardiac disease, including obesity, inflammation, diabetes and dyslipidemia, are essential in caring for patients with AS.
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Affiliation(s)
- Alessandra Brofferio
- National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD, USA.
| | - Vandana Sachdev
- National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD, USA
| | - Hwaida Hannoush
- National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD, USA
| | | | | | - Stanislav Sidenko
- National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD, USA
| | - Anna Noreuil
- National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD, USA
| | - Arlene Sirajuddin
- National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD, USA
| | - Joy Bryant
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Joan C Han
- Section on Growth and Obesity, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA; Departments of Pediatrics and Physiology, University of Tennessee Health Science Center, and Children's Foundation Research Institute, Le Bonheur Children's Hospital, Memphis, TN, USA
| | - Andrew E Arai
- National Heart, Lung, and Blood Institute (NHLBI), National Institutes of Health, Bethesda, MD, USA
| | - William A Gahl
- Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Meral Gunay-Aygun
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA; Office of the Clinical Director, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA; Johns Hopkins University School of Medicine, Department of Pediatrics and McKusick-Nathans Institute of Genetic Medicine, Baltimore, MD, USA
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16
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Dotan G, Khetan V, Marshall JD, Affel E, Armiger-George D, Naggert JK, Collin GB, Levin AV. Spectral-domain optical coherence tomography findings in Alström syndrome. Ophthalmic Genet 2017; 38:440-445. [PMID: 28112973 DOI: 10.1080/13816810.2016.1257029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND Alström syndrome is a multi-system recessive disorder caused by mutations in ALMS1 gene. The aim of this study was to characterize morphological retinal changes in Alström patients using spectral-domain optical coherence tomography. METHODS We studied volunteer patients attending the conference of Alström Syndrome International, a support group for affected families, using hand-held spectral-domain optical coherence tomography (SD-OCT) in an office setting. Patients had a clinical dilated retinal examination. Past medical records were reviewed. RESULTS Twenty-two Alström patients (mean age 17 years, range 2-38 years, 12 males) were studied. OCT imaging demonstrated that central macular OCT changes are often mild during the first decade of life and gradually progress, demonstrating disruption of normal retinal architecture, and progressive loss of photoreceptors and retinal pigment epithelium. Other changes found included hyperreflectivities in all retinal layers, severe retinal wrinkling, optic nerve drusen, and vitreoretinal separation. Vision correlated with severity of OCT macular changes (r = 0.89, p = 0.002). CONCLUSIONS This study reports on OCT findings in a large group of patients with Alström syndrome. We document a panretinal gradual progression of retinal changes, which are often mild during the first years of life. Previously unreported observations include intraretinal opacities, optic nerve drusen, and foveal contour abnormalities. Morphological retinal changes demonstrated by SD-OCT may help in understanding the pathophysiology of the disease and defining strategies for treatment such as gene therapy.
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Affiliation(s)
- Gad Dotan
- a Ophthalmology Department, Tel Aviv Medical Center, Sackler School of Medicine , Tel Aviv University , Tel Aviv , Israel.,b Pediatric Ophthalmology and Ocular Genetics, Wills Eye Hospital , Philadelphia , Pennsylvania , USA
| | - Vikas Khetan
- b Pediatric Ophthalmology and Ocular Genetics, Wills Eye Hospital , Philadelphia , Pennsylvania , USA.,c Department of Vitreoretina and Ocular Oncology , Sankara Nethralaya , Chennai , India
| | | | - Elizabeth Affel
- e Diagnostic Center, Wills Eye Hosptial , Philadelphia , Pennsylvania , USA
| | | | | | | | - Alex V Levin
- b Pediatric Ophthalmology and Ocular Genetics, Wills Eye Hospital , Philadelphia , Pennsylvania , USA.,g Sidney Kimmel Medical College of Thomas Jefferson University , Philadelphia , Pennsylvania , USA
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Chakroun A, Ben Said M, Ennouri A, Achour I, Mnif M, Abid M, Ghorbel A, Marshall JD, Naggert JK, Masmoudi S. Long-term clinical follow-up and molecular testing for diagnosis of the first Tunisian family with Alström syndrome. Eur J Med Genet 2016; 59:444-51. [PMID: 27523285 DOI: 10.1016/j.ejmg.2016.08.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 06/16/2016] [Accepted: 08/08/2016] [Indexed: 12/20/2022]
Abstract
Alström syndrome is a clinically complex disorder characterized by progressive degeneration of sensory functions, resulting in visual and audiological impairment as well as metabolic disturbances. It is caused by recessively inherited mutations in the ALMS1 gene, which codes for a centrosomal/basal body protein. The purpose of this study was to investigate the genetic and clinical features of two Tunisian affected siblings with Alström syndrome. Detailed clinical examinations were performed including complete ophthalmic examination, serial audiograms and several biochemical and hormonal blood tests. For the molecular study, first genomic DNA was isolated using a standard protocol. Then, linkage analysis with microsatellite markers was performed and DNA array was used to detect known mutations. Subsequently, all ALMS1 exons were simultaneously sequenced for one affected patient with the TaGSCAN targeted sequencing panel. Finally, segregation of the causal variant was performed by Sanger sequencing. Both affected siblings had cone rod dystrophy with impaired visual acuity, sensorineural hearing loss and truncal obesity. One affected individual showed insulin resistance without diabetes mellitus. Other clinical features including cardiac and pulmonary dysfunction, hypothyroidism, hyperlipidemia, acanthosis nigricans, renal and hepatic dysfunction were absent. Genetic analysis showed the presence of a homozygous splice site mutation (c.10388-2A > G) in both affected siblings. Although Alström syndrome is relatively well characterized disease, this syndrome is probably misdiagnosed in Tunisia. Here, we describe the first report of Tunisian patients affected by this syndrome and carrying a homozygous ALMS1 mutation. The diagnosis was suspected after long-term clinical follow-up and confirmed by genetic testing.
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Affiliation(s)
- Amine Chakroun
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, Tunisia; Department of Otorhinolaryngology, Habib Bourguiba Teaching Hospital, University of Sfax, Tunisia.
| | - Mariem Ben Said
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, Tunisia
| | - Amine Ennouri
- Department of Ophthalmology, Habib Bourguiba Teaching Hospital, University of Sfax, Tunisia
| | - Imen Achour
- Department of Otorhinolaryngology, Habib Bourguiba Teaching Hospital, University of Sfax, Tunisia
| | - Mouna Mnif
- Department of Endocrinology, Hedi Chaker Teaching Hospital, University of Sfax, Tunisia
| | - Mohamed Abid
- Department of Endocrinology, Hedi Chaker Teaching Hospital, University of Sfax, Tunisia
| | - Abdelmonem Ghorbel
- Department of Otorhinolaryngology, Habib Bourguiba Teaching Hospital, University of Sfax, Tunisia
| | | | | | - Saber Masmoudi
- Laboratory of Molecular and Cellular Screening Processes, Center of Biotechnology of Sfax, Tunisia
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18
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Abstract
Regulation of vesicle trafficking to lysosomes and lysosome-related organelles (LROs) as well as regulation of the size of these organelles are critical to maintain their functions. Disruption of the lysosomal trafficking regulator (LYST) results in Chediak-Higashi syndrome (CHS), a rare autosomal recessive disorder characterized by oculocutaneous albinism, prolonged bleeding, severe immunodeficiency, recurrent bacterial infection, neurologic dysfunction and hemophagocytic lympohistiocytosis (HLH). The classic diagnostic feature of the syndrome is enlarged LROs in all cell types, including lysosomes, melanosomes, cytolytic granules and platelet dense bodies. The most striking CHS ocular pathology observed is an enlargement of melanosomes in the retinal pigment epithelium (RPE), which leads to aberrant distribution of eye pigmentation, and results in photophobia and decreased visual acuity. Understanding the molecular function of LYST and identification of its interacting partners may provide therapeutic targets for CHS and other diseases associated with the regulation of LRO size and/or vesicle trafficking, such as asthma, urticaria and Leishmania amazonensis infections.
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Affiliation(s)
- Xiaojie Ji
- The Jackson Laboratory, 04609, Bar Harbor, ME, USA. .,Graduate School of Biomedical Sciences and Engineering, University of Maine, 600 Main Street, Orono, USA.
| | - Bo Chang
- The Jackson Laboratory, 04609, Bar Harbor, ME, USA.
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19
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Charette JR, Samuels IS, Yu M, Stone L, Hicks W, Shi LY, Krebs MP, Naggert JK, Nishina PM, Peachey NS. A Chemical Mutagenesis Screen Identifies Mouse Models with ERG Defects. Adv Exp Med Biol 2016; 854:177-83. [PMID: 26427409 DOI: 10.1007/978-3-319-17121-0_24] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mouse models provide important resources for many areas of vision research, pertaining to retinal development, retinal function and retinal disease. The Translational Vision Research Models (TVRM) program uses chemical mutagenesis to generate new mouse models for vision research. In this chapter, we report the identification of mouse models for Grm1, Grk1 and Lrit3. Each of these is characterized by a primary defect in the electroretinogram. All are available without restriction to the research community.
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Affiliation(s)
| | - Ivy S Samuels
- Louis Stokes Cleveland VA Medical Center, 44106, Cleveland, OH, USA.
| | - Minzhong Yu
- Cole Eye Institute, Cleveland Clinic, 44195, Cleveland, OH, USA.
| | - Lisa Stone
- The Jackson Laboratory, 04609, Bar Harbor, ME, USA.
| | - Wanda Hicks
- The Jackson Laboratory, 04609, Bar Harbor, ME, USA.
| | - Lan Ying Shi
- The Jackson Laboratory, 04609, Bar Harbor, ME, USA.
| | - Mark P Krebs
- The Jackson Laboratory, 04609, Bar Harbor, ME, USA.
| | | | | | - Neal S Peachey
- Louis Stokes Cleveland VA Medical Center, 44106, Cleveland, OH, USA.
- Cole Eye Institute, Cleveland Clinic, 44195, Cleveland, OH, USA.
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA.
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20
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Citton V, Maffei P, Marshall JD, Baglione A, Collin GB, Milan G, Vettor R, Naggert JK, Manara R. Pituitary morphovolumetric changes in Alström syndrome. J Neuroradiol 2015; 43:195-9. [PMID: 26704672 DOI: 10.1016/j.neurad.2015.10.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2015] [Revised: 10/19/2015] [Accepted: 10/26/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE Alström syndrome (AS) is a rare monogenic ciliopathy characterized by cone-code dystrophy, leading to early blindness, and obesity. Early endocrinological dysfunctions, especially growth hormone deficiency and hypogonadism, are detected in about half of AS patients. This MRI study investigates the presence of pituitary gland abnormalities in a large cohort of AS patients. METHODS Pituitary morphological changes (gland flattening with partial or total empty sella) were evaluated on midsagittal high-resolution T1-weighted images of 32 AS patients (mean-age 23.2±9.4 years; range: 6-45, 15 females) and 21 unrelated healthy subjects (mean age 23.2±11.2 years; range: 6-43; 10 females). RESULTS Among AS patients, 11/32 (34%) had total empty sella and 6/32 (19%) partial empty sella, while 3/21 (14%) of controls had partial empty sella and none presented with total empty sella (P<0.005). AS patients harboring a total or partial empty sella did not differ from those with normal pituitary gland for gender (P=0.98), BMI (P=0.10) or visual impairment (P=0.21), while the presence of empty sella was associated with an older age (P=0.007) being especially frequent above the age of 30. CONCLUSIONS Total or partial empty sella appears commonly during the course of AS. Pituitary gland flattening might represent the morphological underpinning of subtle endocrinologic dysfunctions and raises the need to further investigate the pituitary function in this rare ciliopathy.
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Affiliation(s)
- Valentina Citton
- University Hospital of Padua, Department of Neuroradiology, 35100 Padua, Italy.
| | - Pietro Maffei
- Internal Medicine, Department of Medicine, University Hospital of Padua, Padua, Italy
| | | | | | | | - Gabriella Milan
- Internal Medicine, Department of Medicine, University Hospital of Padua, Padua, Italy
| | - Roberto Vettor
- Internal Medicine, Department of Medicine, University Hospital of Padua, Padua, Italy
| | | | - Renzo Manara
- Department of Neurosciences,Neuroradiology Unit, University of Salerno, Salerno, Italy
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21
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Collin GB, Hubmacher D, Charette JR, Hicks WL, Stone L, Yu M, Naggert JK, Krebs MP, Peachey NS, Apte SS, Nishina PM. Disruption of murine Adamtsl4 results in zonular fiber detachment from the lens and in retinal pigment epithelium dedifferentiation. Hum Mol Genet 2015; 24:6958-74. [PMID: 26405179 DOI: 10.1093/hmg/ddv399] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 09/21/2015] [Indexed: 12/16/2022] Open
Abstract
Human gene mutations have revealed that a significant number of ADAMTS (a disintegrin-like and metalloproteinase (reprolysin type) with thrombospondin type 1 motifs) proteins are necessary for normal ocular development and eye function. Mutations in human ADAMTSL4, encoding an ADAMTS-like protein which has been implicated in fibrillin microfibril biogenesis, cause ectopia lentis (EL) and EL et pupillae. Here, we report the first ADAMTSL4 mouse model, tvrm267, bearing a nonsense mutation in Adamtsl4. Homozygous Adamtsl4(tvrm267) mice recapitulate the EL phenotype observed in humans, and our analysis strongly suggests that ADAMTSL4 is required for stable anchorage of zonule fibers to the lens capsule. Unexpectedly, homozygous Adamtsl4(tvrm267) mice exhibit focal retinal pigment epithelium (RPE) defects primarily in the inferior eye. RPE dedifferentiation was indicated by reduced pigmentation, altered cellular morphology and a reduction in RPE-specific transcripts. Finally, as with a subset of patients with ADAMTSL4 mutations, increased axial length, relative to age-matched controls, was observed and was associated with the severity of the RPE phenotype. In summary, the Adamtsl4(tvrm267) model provides a valuable tool to further elucidate the molecular basis of zonule formation, the pathophysiology of EL and ADAMTSL4 function in the maintenance of the RPE.
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Affiliation(s)
| | - Dirk Hubmacher
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
| | | | | | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, ME, USA
| | - Minzhong Yu
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA, Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA and
| | | | | | - Neal S Peachey
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH, USA, Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, USA and Louis Stokes Cleveland VA Medical Center, Cleveland, OH, USA
| | - Suneel S Apte
- Department of Biomedical Engineering, Cleveland Clinic Lerner Research Institute, Cleveland, OH, USA
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22
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Maddox DM, Collin GB, Ikeda A, Pratt CH, Ikeda S, Johnson BA, Hurd RE, Shopland LS, Naggert JK, Chang B, Krebs MP, Nishina PM. A Mutation in Syne2 Causes Early Retinal Defects in Photoreceptors, Secondary Neurons, and Müller Glia. Invest Ophthalmol Vis Sci 2015; 56:3776-87. [PMID: 26066746 DOI: 10.1167/iovs.14-16047] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
PURPOSE The purpose of this study was to identify the molecular basis and characterize the pathological consequences of a spontaneous mutation named cone photoreceptor function loss 8 (cpfl8) in a mouse model with a significantly reduced cone electroretinography (ERG) response. METHODS The chromosomal position for the recessive cpfl8 mutation was determined by DNA pooling and by subsequent genotyping with simple sequence length polymorphic markers in an F2 intercross phenotyped by ERG. Genes within the candidate region of both mutants and controls were directly sequenced and compared. The effects of the mutation were examined in longitudinal studies by light microscopy, marker analysis, transmission electron microscopy, and ERG. RESULTS The cpfl8 mutation was mapped to Chromosome 12, and a premature stop codon was identified in the spectrin repeat containing nuclear envelope 2 (Syne2) gene. The reduced cone ERG response was due to a significant reduction in cone photoreceptors. Longitudinal studies of the early postnatal retina indicated that the cone photoreceptors fail to develop properly, rod photoreceptors mislocalize to the inner nuclear layer, and both rods and cones undergo apoptosis prematurely. Moreover, we observed migration defects of secondary neurons and ectopic Müller cell bodies in the outer nuclear layer in early postnatal development. CONCLUSIONS SYNE2 is important for normal retinal development. We have determined that not only is photoreceptor nuclear migration affected, but also the positions of Müller glia and secondary neurons are disturbed early in retinal development. The cpfl8 mouse model will serve as an important resource for further examining the role of nuclear scaffolding and migration in the developing retina.
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Affiliation(s)
| | | | - Akihiro Ikeda
- University of Wisconsin-Madison, Department of Medical Genetics, Madison, Wisconsin, United States
| | | | - Sakae Ikeda
- University of Wisconsin-Madison, Department of Medical Genetics, Madison, Wisconsin, United States
| | - Britt A Johnson
- University of Wisconsin-Madison, Department of Medical Genetics, Madison, Wisconsin, United States 3University of Miami, Miller School of Medicine, Miami, Florida, United States
| | - Ron E Hurd
- The Jackson Laboratory Bar Harbor, Maine, United States
| | | | | | - Bo Chang
- The Jackson Laboratory Bar Harbor, Maine, United States
| | - Mark P Krebs
- The Jackson Laboratory Bar Harbor, Maine, United States
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23
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Marshall JD, Muller J, Collin GB, Milan G, Kingsmore SF, Dinwiddie D, Farrow EG, Miller NA, Favaretto F, Maffei P, Dollfus H, Vettor R, Naggert JK. Alström Syndrome: Mutation Spectrum of ALMS1. Hum Mutat 2015; 36:660-8. [PMID: 25846608 DOI: 10.1002/humu.22796] [Citation(s) in RCA: 108] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 03/25/2015] [Accepted: 03/29/2015] [Indexed: 12/24/2022]
Abstract
Alström Syndrome (ALMS), a recessive, monogenic ciliopathy caused by mutations in ALMS1, is typically characterized by multisystem involvement including early cone-rod retinal dystrophy and blindness, hearing loss, childhood obesity, type 2 diabetes mellitus, cardiomyopathy, fibrosis, and multiple organ failure. The precise function of ALMS1 remains elusive, but roles in endosomal and ciliary transport and cell cycle regulation have been shown. The aim of our study was to further define the spectrum of ALMS1 mutations in patients with clinical features of ALMS. Mutational analysis in a world-wide cohort of 204 families identified 109 novel mutations, extending the number of known ALMS1 mutations to 239 and highlighting the allelic heterogeneity of this disorder. This study represents the most comprehensive mutation analysis in patients with ALMS, identifying the largest number of novel mutations in a single study worldwide. Here, we also provide an overview of all ALMS1 mutations identified to date.
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Affiliation(s)
- Jan D Marshall
- The Jackson Laboratory, Bar Harbor, Maine.,Alström Syndrome International, Mount Desert, Maine
| | - Jean Muller
- IGBMC, CNRS UMR 7104/INSERM U964/University of Strasbourg, Illkirch Cedex, France.,Laboratoire ICUBE, UMR CNRS 7357, LBGI, Université de Strasbourg, Strasbourg, France.,Laboratoire de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Strasbourg Cedex, France
| | | | | | - Stephen F Kingsmore
- Center for Pediatric Genomic Medicine, Children's Mercy Hospital, Kansas City, Missouri
| | - Darrell Dinwiddie
- Center for Pediatric Genomic Medicine, Children's Mercy Hospital, Kansas City, Missouri.,Department of Pediatrics, University of New Mexico, Albuquerque, New Mexico
| | - Emily G Farrow
- Center for Pediatric Genomic Medicine, Children's Mercy Hospital, Kansas City, Missouri
| | - Neil A Miller
- Center for Pediatric Genomic Medicine, Children's Mercy Hospital, Kansas City, Missouri
| | | | - Pietro Maffei
- Department of Medicine, University of Padua, Padua, Italy
| | - Hélène Dollfus
- Laboratoire de Génétique médicale, UMR_S INSERM U1112, IGMA, Faculté de Médecine FMTS, Université de Strasbourg, Strasbourg, France.,Service de Génétique Médicale, Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO), Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Roberto Vettor
- Department of Medicine, University of Padua, Padua, Italy
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24
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Butler MG, Wang K, Marshall JD, Naggert JK, Rethmeyer JA, Gunewardena SS, Manzardo AM. Coding and noncoding expression patterns associated with rare obesity-related disorders: Prader-Willi and Alström syndromes. ACTA ACUST UNITED AC 2015; 2015:53-75. [PMID: 25705109 DOI: 10.2147/agg.s74598] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Obesity is accompanied by hyperphagia in several classical genetic obesity-related syndromes that are rare, including Prader-Willi syndrome (PWS) and Alström syndrome (ALMS). We compared coding and noncoding gene expression in adult males with PWS, ALMS, and nonsyndromic obesity relative to nonobese males using readily available lymphoblastoid cells to identify disease-specific molecular patterns and disturbed mechanisms in obesity. We found 231 genes upregulated in ALMS compared with nonobese males, but no genes were found to be upregulated in obese or PWS males and 124 genes were downregulated in ALMS. The metallothionein gene (MT1X) was significantly downregulated in ALMS, in common with obese males. Only the complex SNRPN locus was disturbed (downregulated) in PWS along with several downregulated small nucleolar RNAs (snoRNAs) in the 15q11-q13 region (SNORD116, SNORD109B, SNORD109A, SNORD107). Eleven upregulated and ten downregulated snoRNAs targeting multiple genes impacting rRNA processing, developmental pathways, and associated diseases were found in ALMS. Fifty-two miRNAs associated with multiple, overlapping gene expression disturbances were upregulated in ALMS, and four were shared with obese males but not PWS males. For example, seven passenger strand microRNAs (miRNAs) (miR-93*, miR-373*, miR-29b-2*, miR-30c-1*, miR27a*, miR27b*, and miR-149*) were disturbed in association with six separate downregulated target genes (CD68, FAM102A, MXI1, MYO1D, TP53INP1, and ZRANB1). Cell cycle (eg, PPP3CA), transcription (eg, POLE2), and development may be impacted by upregulated genes in ALMS, while downregulated genes were found to be involved with metabolic processes (eg, FABP3), immune responses (eg, IL32), and cell signaling (eg, IL1B). The high number of gene and noncoding RNA disturbances in ALMS contrast with observations in PWS and males with nonsyndromic obesity and may reflect the progressing multiorgan pathology of the ALMS disease process.
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Affiliation(s)
- Merlin G Butler
- Department of Psychiatry and Behavioral Sciences, University of Kansas Medical Center, Kansas City, KS, USA ; Department of Pediatrics, University of Kansas Medical Center, Kansas City, KS, USA
| | - Kun Wang
- Department of Psychiatry and Behavioral Sciences, University of Kansas Medical Center, Kansas City, KS, USA
| | | | | | - Jasmine A Rethmeyer
- Department of Psychiatry and Behavioral Sciences, University of Kansas Medical Center, Kansas City, KS, USA
| | - Sumedha S Gunewardena
- Department of Biostatistics, Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA
| | - Ann M Manzardo
- Department of Psychiatry and Behavioral Sciences, University of Kansas Medical Center, Kansas City, KS, USA
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25
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Manara R, Citton V, Maffei P, Marshall JD, Naggert JK, Milan G, Vettor R, Baglione A, Vitale A, Briani C, Di Salle F, Favaro A. Degeneration and plasticity of the optic pathway in Alström syndrome. AJNR Am J Neuroradiol 2015; 36:160-5. [PMID: 25355816 PMCID: PMC7965932 DOI: 10.3174/ajnr.a4115] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/04/2014] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Alström syndrome is a rare inherited ciliopathy in which early progressive cone-rod dystrophy leads to childhood blindness. We investigated functional and structural changes of the optic pathway in Alström syndrome by using MR imaging to provide insight into the underlying pathogenic mechanisms. MATERIALS AND METHODS Eleven patients with genetically proved Alström syndrome (mean age, 23 years; range, 6-45 years; 5 females) and 19 age- and sex-matched controls underwent brain MR imaging. The study protocol included conventional sequences, resting-state functional MR imaging, and diffusion tensor imaging. RESULTS In patients with Alström syndrome, the evaluation of the occipital regions showed the following: 1) diffuse white matter volume decrease while gray matter volume decrease spared the occipital poles (voxel-based morphometry), 2) diffuse fractional anisotropy decrease and radial diffusivity increase while mean and axial diffusivities were normal (tract-based spatial statistics), and 3) reduced connectivity in the medial visual network strikingly sparing the occipital poles (independent component analysis). After we placed seeds in both occipital poles, the seed-based analysis revealed significantly increased connectivity in patients with Alström syndrome toward the left frontal operculum, inferior and middle frontal gyri, and the medial portion of both thalami (left seed) and toward the anterior portion of the left insula (right and left seeds). CONCLUSIONS The protean occipital brain changes in patients with Alström syndrome likely reflect the coexistence of diffuse primary myelin derangement, anterograde trans-synaptic degeneration, and complex cortical reorganization affecting the anterior and posterior visual cortex to different degrees.
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Affiliation(s)
- R Manara
- From the Department of Medicine and Surgery (R.M., A.V., F.D.S.), Neuroradiology, University of Salerno, Salerno, Italy
| | - V Citton
- Department of Radiology (V.C.), Neuroradiology Unit, IRCCS San Camillo Hospital, Venezia, Italy
| | - P Maffei
- Department of Internal Medicine (P.M., G.M., R.V.), University Hospital of Padova, Padova, Italy
| | - J D Marshall
- Jackson Laboratory (J.D.M., J.K.N.), Bar Harbor, Maine
| | - J K Naggert
- Jackson Laboratory (J.D.M., J.K.N.), Bar Harbor, Maine
| | - G Milan
- Department of Internal Medicine (P.M., G.M., R.V.), University Hospital of Padova, Padova, Italy
| | - R Vettor
- Department of Internal Medicine (P.M., G.M., R.V.), University Hospital of Padova, Padova, Italy
| | - A Baglione
- Department of Neurosciences (A.B., C.B., A.F.), University of Padua, Padova, Italy
| | - A Vitale
- From the Department of Medicine and Surgery (R.M., A.V., F.D.S.), Neuroradiology, University of Salerno, Salerno, Italy
| | - C Briani
- Department of Neurosciences (A.B., C.B., A.F.), University of Padua, Padova, Italy
| | - F Di Salle
- From the Department of Medicine and Surgery (R.M., A.V., F.D.S.), Neuroradiology, University of Salerno, Salerno, Italy
| | - A Favaro
- Department of Neurosciences (A.B., C.B., A.F.), University of Padua, Padova, Italy
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26
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Ozantürk A, Marshall JD, Collin GB, Düzenli S, Marshall RP, Candan Ş, Tos T, Esen İ, Taşkesen M, Çayır A, Öztürk Ş, Üstün İ, Ataman E, Karaca E, Özdemir TR, Erol İ, Eroğlu FK, Torun D, Parıltay E, Yılmaz-Güleç E, Karaca E, Atabek ME, Elçioğlu N, Satman İ, Möller C, Muller J, Naggert JK, Özgül RK. The phenotypic and molecular genetic spectrum of Alström syndrome in 44 Turkish kindreds and a literature review of Alström syndrome in Turkey. J Hum Genet 2014; 60:1-9. [PMID: 25296579 DOI: 10.1038/jhg.2014.85] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Revised: 09/06/2014] [Accepted: 09/08/2014] [Indexed: 02/07/2023]
Abstract
Alström syndrome (ALMS) is an autosomal recessive disease characterized by multiple organ involvement, including neurosensory vision and hearing loss, childhood obesity, diabetes mellitus, cardiomyopathy, hypogonadism, and pulmonary, hepatic, renal failure and systemic fibrosis. Alström Syndrome is caused by mutations in ALMS1, and ALMS1 protein is thought to have a role in microtubule organization, intraflagellar transport, endosome recycling and cell cycle regulation. Here, we report extensive phenotypic and genetic analysis of a large cohort of Turkish patients with ALMS. We evaluated 61 Turkish patients, including 11 previously reported, for both clinical spectrum and mutations in ALMS1. To reveal the molecular diagnosis of the patients, different approaches were used in combination, a cohort of patients were screened by the gene array to detect the common mutations in ALMS1 gene, then in patients having any of the common ALMS1 mutations were subjected to direct DNA sequencing or next-generation sequencing for the screening of mutations in all coding regions of the gene. In total, 20 distinct disease-causing nucleotide changes in ALMS1 have been identified, eight of which are novel, thereby increasing the reported ALMS1 mutations by 6% (8/120). Five disease-causing variants were identified in more than one kindred, but most of the alleles were unique to each single patient and identified only once (16/20). So far, 16 mutations identified were specific to the Turkish population, and four have also been reported in other ethnicities. In addition, 49 variants of uncertain pathogenicity were noted, and four of these were very rare and probably or likely deleterious according to in silico mutation prediction analyses. ALMS has a relatively high incidence in Turkey and the present study shows that the ALMS1 mutations are largely heterogeneous; thus, these data from a particular population may provide a unique source for the identification of additional mutations underlying Alström Syndrome and contribute to genotype-phenotype correlation studies.
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Affiliation(s)
- Ayşegül Ozantürk
- Institute of Child Health and Metabolism Unit, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
| | | | | | - Selma Düzenli
- Department of Medical Genetics, Abant İzzet Baysal University, Bolu, Turkey
| | | | - Şükrü Candan
- Department of Medical Genetics, Atatürk State Hospital, Balıkesir, Turkey
| | - Tülay Tos
- Dr. Sami Ulus Maternity and Children's Hospital, Ankara, Turkey
| | - İhsan Esen
- Ankara Pediatric Health and Hematology Oncology Hospital, Ankara,Turkey
| | | | - Atilla Çayır
- Pediatric Endocrinology Unit, Department of Medical Genetics, Atatürk University and Erzurum Regional Training and Research Hospital, Erzurum, Turkey
| | - Şükrü Öztürk
- Department of Medical Genetics, Istanbul Medical Faculty, İstanbul University, İstanbul, Turkey
| | - İhsan Üstün
- Department of Endocrinology, Mustafa Kemal University Hospital, Hatay, Turkey
| | - Esra Ataman
- Department of Medical Genetics, Ege University, İzmir, Turkey
| | - Emin Karaca
- 304;zmir Tepecik Training and Research Hospital Genetic Diagnostic Center, İzmir, Turkey
| | - Taha Reşid Özdemir
- 304;zmir Tepecik Training and Research Hospital Genetic Diagnostic Center, İzmir, Turkey
| | - İlknur Erol
- Division of Pediatric Neurology, Adana Teaching and Medical Research Center, Başkent University, Adana, Turkey
| | - Fehime Kara Eroğlu
- Nephrology Unit, Department of Pediatrics, Hacettepe University, Ankara, Turkey
| | - Deniz Torun
- Gülhane Military Medical Faculty, Department of Medical Genetics, Ankara, Turkey
| | - Erhan Parıltay
- Department of Medical Genetics, Ege University, İzmir, Turkey
| | - Elif Yılmaz-Güleç
- Kanuni Sultan Süleyman Training and Research Hospital, İstanbul, Turkey
| | - Ender Karaca
- Kanuni Sultan Süleyman Training and Research Hospital, İstanbul, Turkey
| | - M Emre Atabek
- Department of Pediatric Endocrinology, Necmettin Erbakan University, Konya, Turkey
| | - Nursel Elçioğlu
- Department of Pediatric Genetics, Marmara University Pendik Hospital, İstanbul, Turkey
| | - İlhan Satman
- Division of Endocrinology and Metabolism, İstanbul Faculty of Medicine, İstanbul University, İstanbul, Turkey
| | - Claes Möller
- Department Audiology, The Swedish Institute for Disability Research, Örebro University Hospital, Örebro, Sweden
| | - Jean Muller
- 1] Laboratoire ICUBE, UMR CNRS 7357, LBGI, Université de Strasbourg, Strasbourg, France [2] Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), CNRS UMR 7104/INSERM U964/Université de Strasbourg, Illkirch, France [3] Laboratoire de diagnostic génétique, Hôtpitaux Universitaires de Strasbourg, Strasbourg, France
| | | | - Rıza Köksal Özgül
- Institute of Child Health and Metabolism Unit, Department of Pediatrics, Faculty of Medicine, Hacettepe University, Ankara, Turkey
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Shenje LT, Andersen P, Halushka MK, Lui C, Fernandez L, Collin GB, Amat-Alarcon N, Meschino W, Cutz E, Chang K, Yonescu R, Batista DAS, Chen Y, Chelko S, Crosson JE, Scheel J, Vricella L, Craig BD, Marosy BA, Mohr DW, Hetrick KN, Romm JM, Scott AF, Valle D, Naggert JK, Kwon C, Doheny KF, Judge DP. Mutations in Alström protein impair terminal differentiation of cardiomyocytes. Nat Commun 2014; 5:3416. [PMID: 24595103 PMCID: PMC3992616 DOI: 10.1038/ncomms4416] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2013] [Accepted: 02/10/2014] [Indexed: 02/08/2023] Open
Abstract
Cardiomyocyte cell division and replication in mammals proceed through embryonic development and abruptly decline soon after birth. The process governing cardiomyocyte cell cycle arrest is poorly understood. Here we carry out whole exome sequencing in an infant with evidence of persistent postnatal cardiomyocyte replication to determine the genetic risk factors. We identify compound heterozygous ALMS1 mutations in the proband, and confirm their presence in her affected sibling, one copy inherited from each heterozygous parent. Next, we recognise homozygous or compound heterozygous truncating mutations in ALMS1 in four other children with high levels of postnatal cardiomyocyte proliferation. Alms1 mRNA knockdown increases multiple markers of proliferation in cardiomyocytes, the percentage of cardiomyocytes in G2/M phases, and the number of cardiomyocytes by 10% in cultured cells. Homozygous Alms1-mutant mice have increased cardiomyocyte proliferation at two weeks postnatal compared to wild-type littermates. We conclude that deficiency of Alström protein impairs postnatal cardiomyocyte cell cycle arrest.
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Affiliation(s)
- Lincoln T Shenje
- 1] Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA [2]
| | - Peter Andersen
- 1] Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA [2]
| | - Marc K Halushka
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Cecillia Lui
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Laviel Fernandez
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | | | - Nuria Amat-Alarcon
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Wendy Meschino
- North York General Hospital, Toronto, Ontario, Canada M2K 1E1
| | - Ernest Cutz
- Division of Pathology, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8
| | - Kenneth Chang
- 1] Division of Pathology, Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8 [2] KK Women's and Children's Hospital and Duke-NUS Graduate Medical School, Singapore 229899, Singapore
| | - Raluca Yonescu
- 1] Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA [2] McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Denise A S Batista
- 1] Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA [2] McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Yan Chen
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Stephen Chelko
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Jane E Crosson
- Division of Cardiology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Janet Scheel
- Division of Cardiology, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Luca Vricella
- Division of Cardiothoracic Surgery, Department of Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Brian D Craig
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Beth A Marosy
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - David W Mohr
- 1] McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA [2] High Throughput Sequencing Facility, Genetic Resources Core Facility, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Kurt N Hetrick
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Jane M Romm
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Alan F Scott
- 1] McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA [2] High Throughput Sequencing Facility, Genetic Resources Core Facility, McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - David Valle
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | | | - Chulan Kwon
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Kimberly F Doheny
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Daniel P Judge
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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Won J, Charette JR, Philip VM, Stearns TM, Zhang W, Naggert JK, Krebs MP, Nishina PM. Genetic modifier loci of mouse Mfrp(rd6) identified by quantitative trait locus analysis. Exp Eye Res 2013; 118:30-5. [PMID: 24200520 DOI: 10.1016/j.exer.2013.10.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/27/2013] [Indexed: 11/25/2022]
Abstract
The identification of genes that modify pathological ocular phenotypes in mouse models may improve our understanding of disease mechanisms and lead to new treatment strategies. Here, we identify modifier loci affecting photoreceptor cell loss in homozygous Mfrp(rd6) mice, which exhibit a slowly progressive photoreceptor degeneration. A cohort of 63 F2 homozygous Mfrp(rd6) mice from a (B6.C3Ga-Mfrp(rd6)/J × CAST/EiJ) F1 intercross exhibited a variable number of cell bodies in the retinal outer nuclear layer at 20 weeks of age. Mice were genotyped with a panel of single nucleotide polymorphism markers, and genotypes were correlated with phenotype by quantitative trait locus (QTL) analysis to map modifier loci. A genome-wide scan revealed a statistically significant, protective candidate locus on CAST/EiJ Chromosome 1 and suggestive modifier loci on Chromosomes 6 and 11. Multiple regression analysis of a three-QTL model indicated that the modifier loci on Chromosomes 1 and 6 together account for 26% of the observed phenotypic variation, while the modifier locus on Chromosome 11 explains only an additional 4%. Our findings indicate that the severity of the Mfrp(rd6) retinal degenerative phenotype in mice depends on the strain genetic background and that a significant modifier locus on CAST/EiJ Chromosome 1 protects against Mfrp(rd6)-associated photoreceptor loss.
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Affiliation(s)
- Jungyeon Won
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | | | - Vivek M Philip
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | | | - Weidong Zhang
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Jürgen K Naggert
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Mark P Krebs
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Patsy M Nishina
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA.
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Romano S, Maffei P, Bettini V, Milan G, Favaretto F, Gardiman M, Marshall JD, Greggio NA, Pozzan GB, Collin GB, Naggert JK, Bronson R, Vettor R. Alström syndrome is associated with short stature and reduced GH reserve. Clin Endocrinol (Oxf) 2013; 79:529-36. [PMID: 23445176 PMCID: PMC3718851 DOI: 10.1111/cen.12180] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 02/01/2013] [Accepted: 02/09/2013] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Alström syndrome (ALMS) is a rare autosomal recessive monogenic disease included in an emerging class of genetic disorders called 'ciliopathies' and is likely to impact the central nervous system as well as metabolic and endocrine function. Individuals with ALMS present clinical features resembling a growth hormone deficiency (GHD) condition, but thus far no study has specifically investigated this aspect in a large population. MATERIAL AND METHODS Twenty-three patients with ALMS (age, 1-52 years; 11 males, 12 females) were evaluated for anthropometric parameters (growth charts and standard deviation score (SDS) of height, weight, BMI), GH secretion by growth hormone-releasing hormone + arginine test (GHRH-arg), bone age, and hypothalamic-pituitary magnetic resonance imaging (MRI). A group of 17 healthy subjects served as controls in the GH secretion study. Longitudinal retrospective and prospective data were utilized. RESULTS The length-for-age measurements from birth to 36 months showed normal growth with most values falling within -0·67 SDS to +1·28 SDS. A progressive decrease in stature-for-age was observed after 10 years of age, with a low final height in almost all ALMS subjects (>16-20 years; mean SDS, -2·22 ± 1·16). The subset of 12 patients with ALMS tested for GHRH-arg showed a significantly shorter stature than age-matched controls (154·7 ± 10·6 cm vs 162·9 ± 4·8 cm, P = 0·009) and a mild increase in BMI (Kg/m(2) ) (27·8 ± 4·8 vs 24·1 ± 2·5, P = 0·007). Peak GH after GHRH-arg was significantly lower in patients with ALMS in comparison with controls (11·9 ± 6·9 μg/l vs 86·1 ± 33·2 μg/l, P < 0·0001). Severe GHD was evident biochemically in 50% of patients with ALMS. The 10 adult ALMS patients with GHD showed a reduced height in comparison with those without GHD (149·7 ± 6·2 cm vs 161·9 ± 9·2 cm, P = 0·04). MRIs of the diencephalic and pituitary regions were normal in 11 of 12 patients. Bone age was advanced in 43% of cases. CONCLUSIONS Our study shows that 50% of nonobese ALMS patients have an inadequate GH reserve to GHRH-arg and may be functionally GH deficient. The short stature reported in ALMS may be at least partially influenced by impairment of GH secretion.
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Affiliation(s)
- S Romano
- Department of Medicine, University of Padua, Padua, Italy
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Citton V, Favaro A, Bettini V, Gabrieli J, Milan G, Greggio NA, Marshall JD, Naggert JK, Manara R, Maffei P. Brain involvement in Alström syndrome. Orphanet J Rare Dis 2013; 8:24. [PMID: 23406482 PMCID: PMC3584911 DOI: 10.1186/1750-1172-8-24] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Accepted: 01/29/2013] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Alström Syndrome (AS) is a rare ciliopathy characterized by cone-rod retinal dystrophy, sensorineural hearing loss, obesity, type 2 diabetes mellitus and cardiomyopathy. Most patients do not present with neurological issues and demonstrate normal intelligence, although delayed psychomotor development and psychiatric disorders have been reported. To date, brain Magnetic Resonance Imaging (MRI) abnormalities in AS have not been explored. METHODS We investigated structural brain changes in 12 genetically proven AS patients (mean-age 22 years; range: 6-45, 6 females) and 19 matched healthy and positive controls (mean-age 23 years; range: 6-43; 12 females) using conventional MRI, Voxel-Based Morphometry (VBM) and Diffusion Tensor Imaging (DTI). RESULTS 6/12 AS patients presented with brain abnormalities such as ventricular enlargement (4/12), periventricular white matter abnormalities (3/12) and lacune-like lesions (1/12); all patients older than 30 years had vascular-like lesions. VBM detected grey and white matter volume reduction in AS patients, especially in the posterior regions. DTI revealed significant fractional anisotropy decrease and radial diffusivity increase in the supratentorial white matter, also diffusely involving those regions that appeared normal on conventional imaging. On the contrary, axial and mean diffusivity did not differ from controls except in the fornix. CONCLUSIONS Brain involvement in Alström syndrome is not uncommon. Early vascular-like lesions, gray and white matter atrophy, mostly involving the posterior regions, and diffuse supratentorial white matter derangement suggest a role of cilia in endothelial cell and oligodendrocyte function.
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Affiliation(s)
- Valentina Citton
- Neuroradiology Unit, IRCCS San Camillo Hospital Venezia, and Department of Neurosciences, University of Padua, Padova, Italy.
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Collin GB, Marshall JD, King BL, Milan G, Maffei P, Jagger DJ, Naggert JK. The Alström syndrome protein, ALMS1, interacts with α-actinin and components of the endosome recycling pathway. PLoS One 2012; 7:e37925. [PMID: 22693585 PMCID: PMC3365098 DOI: 10.1371/journal.pone.0037925] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Accepted: 04/30/2012] [Indexed: 01/26/2023] Open
Abstract
Alström syndrome (ALMS) is a progressive multi-systemic disorder characterized by cone-rod dystrophy, sensorineural hearing loss, childhood obesity, insulin resistance and cardiac, renal, and hepatic dysfunction. The gene responsible for Alström syndrome, ALMS1, is ubiquitously expressed and has multiple splice variants. The protein encoded by this gene has been implicated in ciliary function, cell cycle control, and intracellular transport. To gain better insight into the pathways through which ALMS1 functions, we carried out a yeast two hybrid (Y2H) screen in several mouse tissue libraries to identify ALMS1 interacting partners. The majority of proteins found to interact with the murine carboxy-terminal end (19/32) of ALMS1 were α-actinin isoforms. Interestingly, several of the identified ALMS1 interacting partners (α-actinin 1, α-actinin 4, myosin Vb, rad50 interacting 1 and huntingtin associated protein1A) have been previously associated with endosome recycling and/or centrosome function. We examined dermal fibroblasts from human subjects bearing a disruption in ALMS1 for defects in the endocytic pathway. Fibroblasts from these patients had a lower uptake of transferrin and reduced clearance of transferrin compared to controls. Antibodies directed against ALMS1 N- and C-terminal epitopes label centrosomes and endosomal structures at the cleavage furrow of dividing MDCK cells, respectively, suggesting isoform-specific cellular functions. Our results suggest a role for ALMS1 variants in the recycling endosome pathway and give us new insights into the pathogenesis of a subset of clinical phenotypes associated with ALMS.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Jan D. Marshall
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Benjamin L. King
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- Mount Desert Island Biological Laboratory, Salisbury Cove, Maine, United States of America
| | - Gabriella Milan
- Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - Pietro Maffei
- Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - Daniel J. Jagger
- UCL Ear Institute, University College London, London, United Kingdom
| | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- * E-mail:
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Taşdemir S, Güzel-Ozantürk A, Marshall JD, Collin GB, Ozgül RK, Narin N, Dündar M, Naggert JK. Atypical presentation and a novel mutation in ALMS1: implications for clinical and molecular diagnostic strategies for Alström syndrome. Clin Genet 2012; 83:96-8. [PMID: 22533542 DOI: 10.1111/j.1399-0004.2012.01883.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Maddox DM, Ikeda S, Ikeda A, Zhang W, Krebs MP, Nishina PM, Naggert JK. An allele of microtubule-associated protein 1A (Mtap1a) reduces photoreceptor degeneration in Tulp1 and Tub Mutant Mice. Invest Ophthalmol Vis Sci 2012; 53:1663-9. [PMID: 22323461 DOI: 10.1167/iovs.11-8871] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify genes that modify photoreceptor cell loss in the retinas of homozygous Tulp1(tm1Pjn) and Tub(tub) mice, which exhibit juvenile retinitis pigmentosa. METHODS Modifier loci were identified by genetic quantitative trait locus analysis. F2 Tulp1(tm1Pjn/tm1Pjn) mutant mice from a B6-Tulp1(tm1Pjn/tm1Pjn) × AKR/J intercross were genotyped with a panel of single nucleotide polymorphism markers and phenotyped by histology for photoreceptor nuclei remaining at 9 weeks of age. Genotype and phenotype data were correlated and examined with Pseudomarker 2.02 using 128 imputations to map modifier loci. Thresholds for the 63%, 10%, 5%, and 1% significance levels were obtained from 100 permutations. A significant, protective candidate modifier was identified by bioinformatic analysis and confirmed by crossing transgenic mice bearing a protective allele of this gene with Tulp1- and Tub-deficient mice. RESULTS A significant, protective modifier locus on chromosome 2 and a suggestive locus on chromosome 13 that increases photoreceptor loss were identified in a B6-Tulp1(tm1Pjn/tm1Pjn) × AKR/J intercross. The chromosome 2 locus mapped near Mtap1a, which encodes a protein associated with microtubule-based intracellular transport and synapse function. The protective Mtap1a(129P2/OlaHsd) allele was shown to reduce photoreceptor loss in both Tulp1(tm1Pjn/tm1Pjn) and Tub(tub/tub) mice. CONCLUSIONS It was demonstrated that the gene Mtap1a, which modifies hearing loss in Tub(tub/tub) mice, also modifies retinal degeneration in Tub(tub/tub) and Tulp1(tm1Pjn/tm1Pjn) mice. These results suggest that functionally nonredundant members of the TULP family (TUB and TULP1) share a common functional interaction with MTAP1A.
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Collin GB, Won J, Hicks WL, Cook SA, Nishina PM, Naggert JK. Meckelin is necessary for photoreceptor intraciliary transport and outer segment morphogenesis. Invest Ophthalmol Vis Sci 2012; 53:967-74. [PMID: 22247471 PMCID: PMC3317434 DOI: 10.1167/iovs.11-8766] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Revised: 12/21/2011] [Accepted: 12/30/2011] [Indexed: 01/16/2023] Open
Abstract
PURPOSE Cilia, complex structures found ubiquitously in most vertebrate cells, serve a variety of functions ranging from cell and fluid movement, cell signaling, tissue homeostasis, to sensory perception. Meckelin is a component of ciliary and cell membranes and is encoded by Tmem67 (Mks3). In this study, the retinal morphology and ciliary function in a mouse model for Meckel Syndrome Type 3 (MKS3) throughout the course of photoreceptor development was examined. METHODS To study the effects of a disruption in the Mks3 gene on the retina, the authors introduced a functional allele of Pde6b into B6C3Fe a/a-bpck/J mice and evaluated their retinas by ophthalmoscopic, histologic, and ultrastructural examination. In addition, immunofluorescence microscopy was used to assess protein trafficking through the connecting cilium and to examine the localization of ciliary and synaptic proteins in Tmem67(bpck) mice and controls. RESULTS Photoreceptors degenerate early and rapidly in bpck/bpck mutant mice. In addition, phototransduction proteins, such as rhodopsin, arrestin, and transducin, are mislocalized. Ultrastructural examination of photoreceptors reveal morphologically intact connecting cilia but dysmorphic and misoriented outer segment (OS) discs, at the earliest time point examined. CONCLUSIONS These findings underscore the important role for meckelin in intraciliary transport of phototransduction molecules and their effects on subsequent OS morphogenesis and maintenance.
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Möller A, Xie SQ, Hosp F, Lang B, Phatnani HP, James S, Ramirez F, Collin GB, Naggert JK, Babu MM, Greenleaf AL, Selbach M, Pombo A. Proteomic analysis of mitotic RNA polymerase II reveals novel interactors and association with proteins dysfunctional in disease. Mol Cell Proteomics 2011; 11:M111.011767. [PMID: 22199231 DOI: 10.1074/mcp.m111.011767] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RNA polymerase II (RNAPII) transcribes protein-coding genes in eukaryotes and interacts with factors involved in chromatin remodeling, transcriptional activation, elongation, and RNA processing. Here, we present the isolation of native RNAPII complexes using mild extraction conditions and immunoaffinity purification. RNAPII complexes were extracted from mitotic cells, where they exist dissociated from chromatin. The proteomic content of native complexes in total and size-fractionated extracts was determined using highly sensitive LC-MS/MS. Protein associations with RNAPII were validated by high-resolution immunolocalization experiments in both mitotic cells and in interphase nuclei. Functional assays of transcriptional activity were performed after siRNA-mediated knockdown. We identify >400 RNAPII associated proteins in mitosis, among these previously uncharacterized proteins for which we show roles in transcriptional elongation. We also identify, as novel functional RNAPII interactors, two proteins involved in human disease, ALMS1 and TFG, emphasizing the importance of gene regulation for normal development and physiology.
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Affiliation(s)
- André Möller
- MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital Campus, London W12 0NN, United Kingdom.
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Taşkesen M, Collin GB, Evsikov AV, Güzel A, Özgül RK, Marshall JD, Naggert JK. Novel Alu retrotransposon insertion leading to Alström syndrome. Hum Genet 2011; 131:407-13. [PMID: 21877133 DOI: 10.1007/s00439-011-1083-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 08/17/2011] [Indexed: 01/12/2023]
Abstract
Alström syndrome is a clinically complex disorder characterized by childhood retinal degeneration leading to blindness, sensorineural hearing loss, obesity, type 2 diabetes mellitus, cardiomyopathy, systemic fibrosis, and pulmonary, hepatic, and renal failure. Alström syndrome is caused by recessively inherited mutations in the ALMS1 gene, which codes for a putative ciliary protein. Alström syndrome is characterized by extensive allelic heterogeneity, however, founder effects have been observed in some populations. To date, more than 100 causative ALMS1 mutations have been identified, mostly frameshift and non-sense alterations resulting in termination signals in ALMS1. Here, we report a complex Turkish kindred in which sequence analysis uncovered an insertion of a novel 333 basepair Alu Ya5 SINE retrotransposon in the ALMS1 coding sequence, a previously unrecognized mechanism underlying the mutations causing Alström syndrome. It is extraordinarily rare to encounter the insertion of an Alu retrotransposon in the coding sequence of a gene. The high frequency of the mutant ALMS1 allele in this isolated population suggests that this recent retrotransposition event spreads quickly, and may be used as a model to study the population dynamics of deleterious alleles in isolated communities.
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Affiliation(s)
- Mustafa Taşkesen
- Department of Pediatrics, Dicle University School of Medicine, 21280 Diyarbakır, Turkey
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Maddox DM, Hicks WL, Vollrath D, LaVail MM, Naggert JK, Nishina PM. An ENU-induced mutation in the Mertk gene (Mertknmf12) leads to a slow form of retinal degeneration. Invest Ophthalmol Vis Sci 2011; 52:4703-9. [PMID: 21436282 PMCID: PMC3175976 DOI: 10.1167/iovs.10-7077] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 02/15/2011] [Accepted: 03/07/2011] [Indexed: 12/14/2022] Open
Abstract
PURPOSE To determine the basis and to characterize the phenotype of a chemically induced mutation in a mouse model of retinal degeneration. METHODS Screening by indirect ophthalmoscopy identified a line of N-ethyl-N-nitrosourea (ENU) mutagenized mice demonstrating retinal patches. Longitudinal studies of retinal histologic sections showed photoreceptors in the peripheral retina undergoing slow, progressive degeneration. The mutation was named neuroscience mutagenesis facility 12 (nmf12), and mapping localized the critical region to Chromosome 2. RESULTS Sequencing of nmf12 DNA revealed a point mutation in the c-mer tyrosine kinase gene, designated Mertk(nmf12). We detected elevated levels of tumor necrosis factor (Tnf, previously Tnfa) in retinas of Mertk(nmf12) homozygotes relative to wild-type controls and investigated whether the increase of TNF, an inflammatory cytokine produced by macrophages/monocytes that signals intracellularly to cause necrosis or apoptosis, could underlie the retinal degeneration observed in Mertk(nmf12) homozygotes. Mertk(nmf12) homozygous mice were mated to mice lacking the entire Tnf gene and partial coding sequences of the Lta (Tnfb) and Ltb (Tnfc) genes.(2) B6.129P2-Ltb/Tnf/Lta(tm1Dvk)/J homozygotes did not exhibit a retinal degeneration phenotype and will, hereafter, be referred to as Tnfabc(-/-) mice. Surprisingly, mice homozygous for both the Mertk(nmf12) and the Ltb/Tnf/Lta(tm1Dvk) allele (Tnfabc(-/-)) demonstrated an increase in the rate of retinal degeneration. CONCLUSIONS These findings illustrate that a mutation in the Mertk gene leads to a significantly slower progressive retinal degeneration compared with other alleles of Mertk. These results demonstrate that TNF family members play a role in protecting photoreceptors of Mertk(nmf12) homozygotes from cell death.
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Affiliation(s)
- Dennis M. Maddox
- From the Nishina Laboratory and
- Genetic Resource Sciences, The Jackson Laboratory, Bar Harbor, Maine
| | | | - Douglas Vollrath
- Stanford University School of Medicine, Palo Alto, California; and
| | - Matthew M. LaVail
- Beckman Vision Center, University of California, San Francisco, California
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Boldt K, Mans DA, Won J, van Reeuwijk J, Vogt A, Kinkl N, Letteboer SJF, Hicks WL, Hurd RE, Naggert JK, Texier Y, den Hollander AI, Koenekoop RK, Bennett J, Cremers FPM, Gloeckner CJ, Nishina PM, Roepman R, Ueffing M. Disruption of intraflagellar protein transport in photoreceptor cilia causes Leber congenital amaurosis in humans and mice. J Clin Invest 2011; 121:2169-80. [PMID: 21606596 DOI: 10.1172/jci45627] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Accepted: 04/12/2011] [Indexed: 01/19/2023] Open
Abstract
The mutations that cause Leber congenital amaurosis (LCA) lead to photoreceptor cell death at an early age, causing childhood blindness. To unravel the molecular basis of LCA, we analyzed how mutations in LCA5 affect the connectivity of the encoded protein lebercilin at the interactome level. In photoreceptors, lebercilin is uniquely localized at the cilium that bridges the inner and outer segments. Using a generally applicable affinity proteomics approach, we showed that lebercilin specifically interacted with the intraflagellar transport (IFT) machinery in HEK293T cells. This interaction disappeared when 2 human LCA-associated lebercilin mutations were introduced, implicating a specific disruption of IFT-dependent protein transport, an evolutionarily conserved basic mechanism found in all cilia. Lca5 inactivation in mice led to partial displacement of opsins and light-induced translocation of arrestin from photoreceptor outer segments. This was consistent with a defect in IFT at the connecting cilium, leading to failure of proper outer segment formation and subsequent photoreceptor degeneration. These data suggest that lebercilin functions as an integral element of selective protein transport through photoreceptor cilia and provide a molecular demonstration that disrupted IFT can lead to LCA.
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Affiliation(s)
- Karsten Boldt
- Division of Experimental Ophthalmology and Medical Proteome Center, Center of Ophthalmology, University of Tübingen, Tübingen, Germany
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Marshall JD, Maffei P, Collin GB, Naggert JK. Alström syndrome: genetics and clinical overview. Curr Genomics 2011; 12:225-35. [PMID: 22043170 PMCID: PMC3137007 DOI: 10.2174/138920211795677912] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Revised: 03/19/2011] [Accepted: 03/22/2011] [Indexed: 12/11/2022] Open
Abstract
Alström syndrome is a rare autosomal recessive genetic disorder characterized by cone-rod dystrophy, hearing loss, childhood truncal obesity, insulin resistance and hyperinsulinemia, type 2 diabetes, hypertriglyceridemia, short stature in adulthood, cardiomyopathy, and progressive pulmonary, hepatic, and renal dysfunction. Symptoms first appear in infancy and progressive development of multi-organ pathology leads to a reduced life expectancy. Variability in age of onset and severity of clinical symptoms, even within families, is likely due to genetic background.Alström syndrome is caused by mutations in ALMS1, a large gene comprised of 23 exons and coding for a protein of 4,169 amino acids. In general, ALMS1 gene defects include insertions, deletions, and nonsense mutations leading to protein truncations and found primarily in exons 8, 10 and 16. Multiple alternate splice forms exist. ALMS1 protein is found in centrosomes, basal bodies, and cytosol of all tissues affected by the disease. The identification of ALMS1 as a ciliary protein explains the range of observed phenotypes and their similarity to those of other ciliopathies such as Bardet-Biedl syndrome.Studies involving murine and cellular models of Alström syndrome have provided insight into the pathogenic mechanisms underlying obesity and type 2 diabetes, and other clinical problems. Ultimately, research into the pathogenesis of Alström syndrome should lead to better management and treatments for individuals, and have potentially important ramifications for other rare ciliopathies, as well as more common causes of obesity and diabetes, and other conditions common in the general population.
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Affiliation(s)
| | - Pietro Maffei
- Dipartimento di Scienze Mediche e Chirurgiche, Clinica Medica 3, Azienda Ospedaliera di Padova, Italy
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Zulato E, Favaretto F, Veronese C, Campanaro S, Marshall JD, Romano S, Cabrelle A, Collin GB, Zavan B, Belloni AS, Rampazzo E, Naggert JK, Abatangelo G, Sicolo N, Maffei P, Milan G, Vettor R. ALMS1-deficient fibroblasts over-express extra-cellular matrix components, display cell cycle delay and are resistant to apoptosis. PLoS One 2011; 6:e19081. [PMID: 21541333 PMCID: PMC3082548 DOI: 10.1371/journal.pone.0019081] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 03/28/2011] [Indexed: 12/30/2022] Open
Abstract
Alström Syndrome (ALMS) is a rare genetic disorder (483 living cases), characterized by many clinical manifestations, including blindness, obesity, type 2 diabetes and cardiomyopathy. ALMS is caused by mutations in the ALMS1 gene, encoding for a large protein with implicated roles in ciliary function, cellular quiescence and intracellular transport. Patients with ALMS have extensive fibrosis in nearly all tissues resulting in a progressive organ failure which is often the ultimate cause of death. To focus on the role of ALMS1 mutations in the generation and maintenance of this pathological fibrosis, we performed gene expression analysis, ultrastructural characterization and functional assays in 4 dermal fibroblast cultures from ALMS patients. Using a genome-wide gene expression analysis we found alterations in genes belonging to specific categories (cell cycle, extracellular matrix (ECM) and fibrosis, cellular architecture/motility and apoptosis). ALMS fibroblasts display cytoskeleton abnormalities and migration impairment, up-regulate the expression and production of collagens and despite the increase in the cell cycle length are more resistant to apoptosis. Therefore ALMS1-deficient fibroblasts showed a constitutively activated myofibroblast phenotype even if they do not derive from a fibrotic lesion. Our results support a genetic basis for the fibrosis observed in ALMS and show that both an excessive ECM production and a failure to eliminate myofibroblasts are key mechanisms. Furthermore, our findings suggest new roles for ALMS1 in both intra- and extra-cellular events which are essential not only for the normal cellular function but also for cell-cell and ECM-cell interactions.
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Affiliation(s)
- Elisabetta Zulato
- Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - Francesca Favaretto
- Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - Caterina Veronese
- Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - Stefano Campanaro
- Department of Biology, CRIBI (Centro Ricerca Interdipartimentale Biotecnologie Innovative), University of Padua, Padua, Italy
| | - Jan D. Marshall
- The Jackson Laboratory, Bar Harbor, Maine, United State of America
| | - Sara Romano
- Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - Anna Cabrelle
- Department of Clinical and Experimental Medicine, University of Padua, Padua, Italy
| | - Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, United State of America
| | - Barbara Zavan
- Department of Histology, Microbiology and Biomedical Technologies, University of Padua, Padua, Italy
| | - Anna S. Belloni
- Department of Human Anatomy and Physiology, University of Padua, Padua, Italy
| | - Enrica Rampazzo
- Department of Oncology and Surgical Sciences, University of Padua, Padua, Italy
| | | | - Giovanni Abatangelo
- Department of Histology, Microbiology and Biomedical Technologies, University of Padua, Padua, Italy
| | - Nicola Sicolo
- Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - Pietro Maffei
- Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - Gabriella Milan
- Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
| | - Roberto Vettor
- Department of Medical and Surgical Sciences, University of Padua, Padua, Italy
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Pereiro I, Hoskins BE, Marshall JD, Collin GB, Naggert JK, Piñeiro-Gallego T, Oitmaa E, Katsanis N, Valverde D, Beales PL. Arrayed primer extension technology simplifies mutation detection in Bardet-Biedl and Alström syndrome. Eur J Hum Genet 2010; 19:485-8. [PMID: 21157496 DOI: 10.1038/ejhg.2010.207] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Bardet-Biedl syndrome (BBS; OMIM no. 209 900) and Alström syndrome (ALMS; OMIM no. 203 800) are rare, multisystem genetic disorders showing both a highly variable phenotype and considerable phenotypic overlap; they are included in the emerging group of diseases called ciliopathies. The genetic heterogeneity of BBS with 14 causal genes described to date, serves to further complicate mutational analysis. The development of the BBS-ALMS array which detects known mutations in these genes has allowed us to detect at least one mutation in 40.5% of BBS families and in 26.7% of ALMS families validating this as an efficient and cost-effective first pass screening modality. Furthermore, using this method, we found two BBS families segregating three BBS alleles further supporting oligogenicity or modifier roles for additional mutations. We did not observe more than two mutations in any ALMS family.
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Affiliation(s)
- Ines Pereiro
- Departamento de Bioquímica, Genética e Inmunología, Facultad de Biología, Universidad de Vigo, Vigo, Spain
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Won J, Marín de Evsikova C, Smith RS, Hicks WL, Edwards MM, Longo-Guess C, Li T, Naggert JK, Nishina PM. NPHP4 is necessary for normal photoreceptor ribbon synapse maintenance and outer segment formation, and for sperm development. Hum Mol Genet 2010; 20:482-96. [PMID: 21078623 DOI: 10.1093/hmg/ddq494] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Nephronophthisis (NPHP) is an autosomal recessive kidney disease that is often associated with vision and/or brain defects. To date, 11 genes are known to cause NPHP. The gene products, while structurally unrelated, all localize to cilia or centrosomes. Although mouse models of NPHP are available for 9 of the 11 genes, none has been described for nephronophthisis 4 (Nphp4). Here we report a novel, chemically induced mutant, nmf192, that bears a nonsense mutation in exon 4 of Nphp4. Homozygous mutant Nphp4(nmf192/nmf192) mice do not exhibit renal defects, phenotypes observed in human patients bearing mutations in NPHP4, but they do develop severe photoreceptor degeneration and extinguished rod and cone ERG responses by 9 weeks of age. Photoreceptor outer segments (OS) fail to develop properly, and some OS markers mislocalize to the inner segments and outer nuclear layer in the Nphp4(nmf192/nmf192) mutant retina. Despite NPHP4 localization to the transition zone in the connecting cilia (CC), the CC appear to be normal in structure and ciliary transport function is partially retained. Likewise, synaptic ribbons develop normally but then rapidly degenerate by P14. Finally, Nphp4(nmf192/nmf192) male mutants are sterile and show reduced sperm motility and epididymal sperm counts. Although Nphp4(nmf192/nmf192) mice fail to recapitulate the kidney phenotype of NPHP, they will provide a valuable tool to further elucidate how NPHP4 functions in the retina and male reproductive organs.
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Affiliation(s)
- Jungyeon Won
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
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43
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Edwards MM, Marín de Evsikova C, Collin GB, Gifford E, Wu J, Hicks WL, Whiting C, Varvel NH, Maphis N, Lamb BT, Naggert JK, Nishina PM, Peachey NS. Photoreceptor degeneration, azoospermia, leukoencephalopathy, and abnormal RPE cell function in mice expressing an early stop mutation in CLCN2. Invest Ophthalmol Vis Sci 2010; 51:3264-72. [PMID: 20071672 DOI: 10.1167/iovs.09-4887] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the molecular basis and the pathologic consequences of a chemically induced mutation in a mouse model of photoreceptor degeneration, nmf240. METHODS Mice from a G3 N-ethyl-N-nitrosourea mutagenesis program were screened by indirect ophthalmoscopy for abnormal fundi. A chromosomal position for the recessive nmf240 mutation was determined by a genome-wide linkage analysis by use of simple sequence length polymorphic markers in an F2 intercross. The critical region was refined, and candidate genes were screened by direct sequencing. The nmf240 phenotype was characterized by histologic analysis of the retina, brain, and male reproductive organs and by electroretinogram (ERG)-based studies of the retina and retinal pigment epithelium (RPE). RESULTS Clinically, homozygous nmf240 mutants exhibit a grainy retina that progresses to panretinal patches of depigmentation. The mutation was localized to a region on chromosome 16 containing Clcn2, a gene associated with retinal degeneration. Sequencing identified a missense C-T mutation at nucleotide 1063 in Clcn2 that converts a glutamine to a stop codon. Mice homozygous for the Clcn2(nmf240) mutation experience a severe loss of photoreceptor cells at 14 days of age that is preceded by an elongation of RPE apical microvilli. Homozygous mutants also experience leukoencephalopathy in multiple brain areas and male sterility. Despite a normal retinal histology in nmf240 heterozygotes, the ERG light peak, generated by the RPE, is reduced. CONCLUSIONS The nmf240 phenotype closely resembles that reported for Clcn2 knockout mice. The observation that heterozygous nmf240 mice present with a reduced ERG light peak component suggests that CLCN2 is necessary for the generation of this response component.
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Edwards MM, Mammadova-Bach E, Alpy F, Klein A, Hicks WL, Roux M, Simon-Assmann P, Smith RS, Orend G, Wu J, Peachey NS, Naggert JK, Lefebvre O, Nishina PM. Mutations in Lama1 disrupt retinal vascular development and inner limiting membrane formation. J Biol Chem 2010; 285:7697-711. [PMID: 20048158 DOI: 10.1074/jbc.m109.069575] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The Neuromutagenesis Facility at the Jackson Laboratory generated a mouse model of retinal vasculopathy, nmf223, which is characterized clinically by vitreal fibroplasia and vessel tortuosity. nmf223 homozygotes also have reduced electroretinogram responses, which are coupled histologically with a thinning of the inner nuclear layer. The nmf223 locus was mapped to chromosome 17, and a missense mutation was identified in Lama1 that leads to the substitution of cysteine for a tyrosine at amino acid 265 of laminin alpha1, a basement membrane protein. Despite normal localization of laminin alpha1 and other components of the inner limiting membrane, a reduced integrity of this structure was suggested by ectopic cells and blood vessels within the vitreous. Immunohistochemical characterization of nmf223 homozygous retinas demonstrated the abnormal migration of retinal astrocytes into the vitreous along with the persistence of hyaloid vasculature. The Y265C mutation significantly reduced laminin N-terminal domain (LN) interactions in a bacterial two-hybrid system. Therefore, this mutation could affect interactions between laminin alpha1 and other laminin chains. To expand upon these findings, a Lama1 null mutant, Lama1(tm1.1Olf), was generated that exhibits a similar but more severe retinal phenotype than that seen in nmf223 homozygotes. The increased severity of the Lama1 null mutant phenotype is probably due to the complete loss of the inner limiting membrane in these mice. This first report of viable Lama1 mouse mutants emphasizes the importance of this gene in retinal development. The data presented herein suggest that hypomorphic mutations in human LAMA1 could lead to retinal disease.
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Abstract
The TALLYHO/Jng (TH) mouse strain is a polygenic model for type 2 diabetes (T2D) characterized by moderate obesity, impaired glucose tolerance and uptake, insulin resistance, and hyperinsulinemia. The goal of this study was to elucidate the molecular mechanisms responsible for the reduced glucose uptake and insulin resistance in the adipose tissue of this model. The translocation and localization of glucose transporter 4 (GLUT4) to the adipocyte plasma membrane were impaired in TH mice compared to control C57BL6/J (B6) mice. These defects were associated with decreased GLUT4 protein, reduced phosphatidylinositol 3-kinase activity, and alterations in the phosphorylation status of insulin receptor substrate 1 (IRS1). Activation of c-Jun N-terminal kinase 1/2, which can phosphorylate IRS1 on Ser307, was significantly higher in TH mice compared with B6 controls. IRS1 protein but not mRNA levels was found to be lower in TH mice than controls. Immunoprecipitation with anti-ubiquitin and western blot analysis of IRS1 protein revealed increased total IRS1 ubiquitination in adipose tissue of TH mice. Suppressor of cytokine signaling 1, known to promote IRS1 ubiquitination and subsequent degradation, was found at significantly higher levels in TH mice compared with B6. Immunohistochemistry showed that IRS1 colocalized with the 20S proteasome in proteasomal structures in TH adipocytes, supporting the notion that IRS1 is actively degraded. Our findings suggest that increased IRS1 degradation and subsequent impaired GLUT4 mobilization play a role in the reduced glucose uptake in insulin resistant TH mice. Since low-IRS1 levels are often observed in human T2D, the TH mouse is an attractive model to investigate mechanisms of insulin resistance and explore new treatments.
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Affiliation(s)
- Yun Wang
- The Jackson Laboratory, 600 Main Street, Bar Harbor, Maine 04609, USA
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Won J, Gifford E, Smith RS, Yi H, Ferreira PA, Hicks WL, Li T, Naggert JK, Nishina PM. RPGRIP1 is essential for normal rod photoreceptor outer segment elaboration and morphogenesis. Hum Mol Genet 2009; 18:4329-39. [PMID: 19679561 DOI: 10.1093/hmg/ddp385] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The function of the retinitis pigmentosa GTPase regulator interacting protein 1 (RPGRIP1) gene is currently not known. However, mutations within the gene lead to Leber Congenital Amaurosis and autosomal recessive retinitis pigmentosa in human patients. In a previously described knockout mouse model of the long splice variant of Rpgrip1, herein referred to as Rpgrip1(tm1Tili) mice, mislocalization of key outer segment proteins and dysmorphogenesis of outer segment discs preceded subsequent photoreceptor degeneration. In this report, we describe a new mouse model carrying a splice acceptor site mutation in Rpgrip1, herein referred to as Rpgrip1(nmf247) that is phenotypically distinct from Rpgrip1(tm1Tili) mice. Photoreceptor degeneration in homozygous Rpgrip1(nmf247) mice is earlier in onset and more severe when compared with Rpgrip1(tm1Tili) mice. Also, ultrastructural studies reveal that whereas Rpgrip1(nmf247) mutants have a normal structure and number of connecting cilia, unlike Rpgrip1(tm1Tili) mice, they do not elaborate rod outer segments (OS). Therefore, in addition to its role in OS disc morphogenesis, RPGRIP1 is essential for rod OS formation. Our study indicates the absence of multiple Rpgrip1 isoforms in Rpgrip1(nmf247) mice, suggesting different isoforms may play different roles in photoreceptors and underscores the importance of considering splice variants when generating targeted null mutations.
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Affiliation(s)
- Jungyeon Won
- The Jackson Laboratory, Bar Harbor, ME 04609, USA
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Matsumura H, Kano K, Marín de Evsikova C, Young JA, Nishina PM, Naggert JK, Naito K. Transcriptome analysis reveals an unexpected role of a collagen tyrosine kinase receptor gene, Ddr2, as a regulator of ovarian function. Physiol Genomics 2009; 39:120-9. [PMID: 19671659 DOI: 10.1152/physiolgenomics.00073.2009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mice homozygous for the smallie (slie) mutation lack a collagen receptor, discoidin domain receptor 2 (DDR2), and are dwarfed and infertile due to peripheral dysregulation of the endocrine system of unknown etiology. We used a systems biology approach to identify biological networks affected by Ddr2(slie/slie) mutation in ovaries using microarray analysis and validate findings using molecular, cellular, and functional biological assays. Transcriptome analysis indicated several altered gene categories in Ddr2(slie/slie) mutants, including gonadal development, ovulation, antiapoptosis, and steroid hormones. Subsequent biological experiments confirmed the transcriptome analysis predictions. For instance, a significant increase of TUNEL-positive follicles was found in Ddr2(slie/slie) mutants vs. wild type, which confirm the transcriptome prediction for decreased chromatin maintenance and antiapoptosis. Decreases in gene expression were confirmed by RT-PCR and/or qPCR; luteinizing hormone receptor and prostaglandin type E and F receptors in Ddr2(slie/slie) mutants, compared with wild type, confirm hormonal signaling pathways involved in ovulation. Furthermore, deficiencies in immunohistochemistry for DDR2 and luteinizing hormone receptor in the somatic cells, but not the oocytes, of Ddr2(slie/slie) mutant ovaries suggest against an intrinsic defect in germ cells. Indeed, Ddr2(slie/slie) mutants ovulated significantly fewer oocytes; their oocytes were competent to complete meiosis and fertilization in vitro. Taken together, our convergent data signify DDR2 as a novel critical player in ovarian function, which acts upon classical endocrine pathways in somatic, rather than germline, cells.
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Affiliation(s)
- Hirokazu Matsumura
- Laboratory of Applied Genetics, Graduate School of Agricultural and Life Science, University of Tokyo, Tokyo, Japan
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Abstract
Metabolic syndrome (MS) encompasses a clustering of risk factors for cardiovascular disease, including obesity, insulin resistance, and dyslipidemia. We characterized a new mouse model carrying a dominant mutation, C57BL/6J-Nmf15/+ (B6-Nmf15/+), which develops additional complications of MS such as adipose tissue inflammation and cardiomyopathy. A backcross was used to genetically map the Nmf15 locus. Mice were examined in the comprehensive laboratory animal monitoring system, and dual energy X-ray absorptiometry and blood chemistry analyses were performed. Hypothalamic LEPR, SOCS1, and STAT3 phosphorylation were examined. Cardiac function was assessed by echo- and electrocardiography. Adipose tissue inflammation was characterized by in situ hybridization and measurement of Jun kinase activity. The Nmf15 locus mapped to distal mouse chromosome 5 with an LOD (logarithm of odds) score of 13.8. Nmf15 mice developed obesity by 12 weeks of age. Plasma leptin levels were significantly elevated in pre-obese Nmf15 mice at 8 weeks of age and an attenuated STAT3 phosphorylation in the hypothalamus suggests a primary leptin resistance. Adipose tissue from Nmf15 mice showed a remarkable degree of inflammation and macrophage infiltration as indicated by expression of the F4/80 marker and increased phosphorylation of JUN N-terminal kinase 1/2. Lipidosis was observed in tubular epithelial cells and glomeruli of the kidney. Nmf15 mice demonstrate both histological and pathophysiological evidence of cardiomyopathy. The Nmf15 mouse model provides a new entry point into pathways mediating leptin resistance and obesity. It is one of few models that combine many aspects of MS and can be useful for testing new therapeutic approaches for combating obesity complications, particularly cardiomyopathy.
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Affiliation(s)
- Yun Wang
- The Jackson Laboratory, Bar Harbor, Maine 04609, USA
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Lee NC, Marshall JD, Collin GB, Naggert JK, Chien YH, Tsai WY, Hwu WL. Caloric restriction in Alström syndrome prevents hyperinsulinemia. Am J Med Genet A 2009; 149A:666-8. [PMID: 19283853 DOI: 10.1002/ajmg.a.32730] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Alström syndrome (AS; OMIM 203800) is an autosomal recessive disorder characterized by cone-rod dystrophy, dilated cardiomyopathy, sensorineural hearing impairment, developmental delay, and most case had both childhood-onset obesity and hyperinsulinemia. Currently, the pathogenesis of this disease is not clear. Here we report on an 18-month-old boy with Alström syndrome. He had obesity but with normal insulin and glucose levels. Molecular analysis of the ALMS1 gene revealed a 19 base pair homozygous deletion 11116_11134del in exon 16. His body mass index decreased from 25.0 to 20.7 after calorie restriction for 9 months, and his insulin and glucose levels remained normal. Finding in this case suggests that hyperinsulinemia is a secondary event in Alström syndrome, and early-commenced treatment prevents hyperinsulinemia.
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Affiliation(s)
- Ni-Chung Lee
- Department of Medical Genetics, National Taiwan University Hospital, Taipei, Taiwan
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50
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Duchesnes CE, Naggert JK, Tatnell MA, Beckman N, Marnane RN, Rodrigues JA, Halim A, Pontré B, Stewart AW, Wolff GL, Elliott R, Mountjoy KG. New Zealand Ginger mouse: novel model that associates the tyrp1b pigmentation gene locus with regulation of lean body mass. Physiol Genomics 2009; 37:164-74. [PMID: 19293329 DOI: 10.1152/physiolgenomics.90336.2008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The study of spontaneous mutations in mice over the last century has been fundamental to our understanding of normal physiology and mechanisms of disease. Here we studied the phenotype and genotype of a novel mouse model we have called the New Zealand Ginger (NZG/Kgm) mouse. NZG/Kgm mice are very large, rapidly growing, ginger-colored mice with pink eyes. Breeding NZG/Kgm mice with CAST/Ei or C57BL/6J mice showed that the ginger coat colour is a recessive trait, while the excessive body weight and large body size exhibit a semidominant pattern of inheritance. Backcrossing F1 (NZG/Kgm x CAST/Ei) to NZG/Kgm mice to produce the N2 generation determined that the NZG/Kgm mouse has two recessive pigmentation variant genes (oca2(p) and tyrp-1(b)) and that the tyrp-1(b) gene locus associates with large body size. Three coat colors appeared in the N2 generation; ginger, brown, and dark. Strikingly, N2 male coat colour associated with body weight; the brown-colored mice weighed the most followed by ginger and then dark. The male brown coat-colored offspring reached adult body weights indistinguishable from NZG/Kgm males. The large NZG/Kgm mouse body size is a result of excessive lean body mass since these mice are not obese or diabetic. NZG/Kgm mice exhibit an unusual pattern of fat distribution; compared with other mouse strains they have disproportionately higher amounts of subcutaneous and gonadal fat. These mice are susceptible to high-fat diet-induced obesity but are resistant to high-fat diet-induced diabetes. We propose NZG/Kgm mice as a novel model to delineate gene(s) that regulate 1) growth and metabolism, 2) resistance to Type 2 diabetes, and 3) preferential fat deposition in the subcutaneous and gonadal areas.
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Affiliation(s)
- Cécile E Duchesnes
- Department of Physiology, Faculty of Medical and Health Sciences, University of Auckland, New Zealand
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