151
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Tzekov R, Stein L, Kaushal S. Protein misfolding and retinal degeneration. Cold Spring Harb Perspect Biol 2011; 3:a007492. [PMID: 21825021 DOI: 10.1101/cshperspect.a007492] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The retina is a highly complex and specialized organ that performs preliminary analysis of visual information. Composed of highly metabolically active tissue, the retina requires a precise and well-balanced means of maintaining its functional activity during extended periods of time. Maintenance and regulation of a vast array of different structural and functional proteins is required for normal function of the retina. This process is referred to as protein homeostasis and involves a variety of activities, including protein synthesis, folding, transport, degradation, elimination, and recycling. Deregulation of any of these activities can lead to malfunctioning of the retina, from subtle subclinical signs to severe retinal degenerative diseases leading to blindness. Examples of retinal degenerative diseases caused by disruption of protein homeostasis include retinitis pigmentosa and Stargardt's disease. A detailed discussion of the role of disruption in protein homeostasis in these and other retinal diseases is presented, followed by examples of some existing and potential treatments.
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Affiliation(s)
- Radouil Tzekov
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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152
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Hulleman JD, Kaushal S, Balch WE, Kelly JW. Compromised mutant EFEMP1 secretion associated with macular dystrophy remedied by proteostasis network alteration. Mol Biol Cell 2011; 22:4765-75. [PMID: 22031286 PMCID: PMC3237620 DOI: 10.1091/mbc.e11-08-0695] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
R345W EFEMP1 is secreted poorly, causing the macular dystrophy malattia leventinese. A novel assay shows that other substitutions (F, Y, P) at residue 345 impair secretion, partly by reducing native disulfide bonds. EFEMP1 secretion is rescued by reduced growth temperature and translational attenuation—potential strategies to delay disease. An Arg345Trp (R345W) mutation in epidermal growth factor–containing, fibulin-like extracellular matrix protein 1 (EFEMP1) causes its inefficient secretion and the macular dystrophy malattia leventinese/Doyne honeycomb retinal dystrophy (ML/DHRD). To understand the influence of the protein homeostasis (or proteostasis) network in rescuing mutant EFEMP1 misfolding and inefficient secretion linked to ML/DHRD, we developed a convenient and sensitive cell-based luminescence assay to monitor secretion versus intracellular accumulation. Fusing EFEMP1 to Gaussia luciferase faithfully recapitulates mutant EFEMP1 secretion defects observed previously using more cumbersome methodology. To understand what governs mutant intracellular retention, we generated a series of R345 mutants. These mutants revealed that aromatic residue substitutions (i.e., Trp, Tyr, and Phe) at position 345 cause significant EFEMP1 secretion deficiencies. These secretion defects appear to be caused, in part, by reduced native disulfide bonding in domain 6 harboring the 345 position. Finally, we demonstrate that mutant EFEMP1 secretion and proper disulfide formation are enhanced by adaptation of the cellular environment by a reduced growth temperature and/or translational attenuation. This study highlights the mechanisms underlying the inefficient secretion of R345W EFEMP1 and demonstrates that alteration of the proteostasis network may provide a strategy to alleviate or delay the onset of this macular dystrophy.
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Affiliation(s)
- John D Hulleman
- Departments of Chemistry and Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, CA 92037, USA.
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153
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Misfolded proteins and retinal dystrophies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2011; 664:115-21. [PMID: 20238009 DOI: 10.1007/978-1-4419-1399-9_14] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Many mutations associated with retinal degeneration lead to the production of misfolded proteins by cells of the retina. Emerging evidence suggests that these abnormal proteins cause cell death by activating the Unfolded Protein Response, a set of conserved intracellular signaling pathways that detect protein misfolding within the endoplasmic reticulum and control protective and proapoptotic signal transduction pathways. Here, we review the misfolded proteins associated with select types of retinitis pigmentosa, Stargadt-like macular degeneration, and Doyne Honeycomb Retinal Dystrophy and discuss the role that endoplasmic reticulum stress and UPR signaling play in their pathogenesis. Last, we review new therapies for these diseases based on preventing protein misfolding in the retina.
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154
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Jelcick AS, Yuan Y, Leehy BD, Cox LC, Silveira AC, Qiu F, Schenk S, Sachs AJ, Morrison MA, Nystuen AM, DeAngelis MM, Haider NB. Genetic variations strongly influence phenotypic outcome in the mouse retina. PLoS One 2011; 6:e21858. [PMID: 21779340 PMCID: PMC3136482 DOI: 10.1371/journal.pone.0021858] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 06/07/2011] [Indexed: 01/22/2023] Open
Abstract
Variation in genetic background can significantly influence the phenotypic outcome of both disease and non-disease associated traits. Additionally, differences in temporal and strain specific gene expression can also contribute to phenotypes in the mammalian retina. This is the first report of microarray based cross-strain analysis of gene expression in the retina investigating genetic background effects. Microarray analyses were performed on retinas from the following mouse strains: C57BL6/J, AKR/J, CAST/EiJ, and NOD.NON-H2-nb1 at embryonic day 18.5 (E18.5) and postnatal day 30.5 (P30.5). Over 3000 differentially expressed genes were identified between strains and developmental stages. Differential gene expression was confirmed by qRT-PCR, Western blot, and immunohistochemistry. Three major gene networks were identified that function to regulate retinal or photoreceptor development, visual perception, cellular transport, and signal transduction. Many of the genes in these networks are implicated in retinal diseases such as bradyopsia, night-blindness, and cone-rod dystrophy. Our analysis revealed strain specific variations in cone photoreceptor cell patterning and retinal function. This study highlights the substantial impact of genetic background on both development and function of the retina and the level of gene expression differences tolerated for normal retinal function. These strain specific genetic variations may also be present in other tissues. In addition, this study will provide valuable insight for the development of more accurate models for human retinal diseases.
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Affiliation(s)
- Austin S. Jelcick
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Yang Yuan
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Barrett D. Leehy
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Lakeisha C. Cox
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Alexandra C. Silveira
- Ocular Molecular Genetics Institute, Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States of America
| | - Fang Qiu
- Division of Biostatistics, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Sarah Schenk
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Andrew J. Sachs
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Margaux A. Morrison
- Ocular Molecular Genetics Institute, Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States of America
| | - Arne M. Nystuen
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Margaret M. DeAngelis
- Moran Eye Center, University of Utah, Salt Lake City, Utah, United States of America
| | - Neena B. Haider
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute, Boston, Massachusetts, United States of America
- * E-mail:
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155
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DeAngelis MM, Silveira AC, Carr EA, Kim IK. Genetics of age-related macular degeneration: current concepts, future directions. Semin Ophthalmol 2011; 26:77-93. [PMID: 21609220 PMCID: PMC4242505 DOI: 10.3109/08820538.2011.577129] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Age-related macular degeneration (AMD) is a progressive degenerative disease which leads to blindness, affecting the quality of life of millions of Americans. More than 1.75 million individuals in the United States are affected by the advanced form of AMD. The etiological pathway of AMD is not yet fully understood, but there is a clear genetic influence on disease risk. To date, the 1q32 (CFH) and 10q26 (PLEKHA1/ARMS2/HTRA1) loci are the most strongly associated with disease; however, the variation in these genomic regions alone is unable to predict disease development with high accuracy. Therefore, current genetic studies are aimed at identifying new genes associated with AMD and their modifiers, with the goal of discovering diagnostic or prognostic biomarkers. Moreover, these studies provide the foundation for further investigation into the pathophysiology of AMD by utilizing a systems-biology-based approach to elucidate underlying mechanistic pathways.
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Affiliation(s)
- Margaret M. DeAngelis
- Ocular Molecular Genetics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Alexandra C. Silveira
- Ocular Molecular Genetics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Elizabeth A. Carr
- John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Ivana K. Kim
- Retina Service, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
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156
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Song EL, Hou YP, Yu SP, Chen SG, Huang JT, Luo T, Kong LP, Xu J, Wang HQ. EFEMP1 expression promotes angiogenesis and accelerates the growth of cervical cancer in vivo. Gynecol Oncol 2011; 121:174-80. [DOI: 10.1016/j.ygyno.2010.11.004] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 11/02/2010] [Accepted: 11/04/2010] [Indexed: 10/18/2022]
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157
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Identification of a preneoplastic gene expression profile in tubal epithelium of BRCA1 mutation carriers. Neoplasia 2011; 12:993-1002. [PMID: 21170264 DOI: 10.1593/neo.101044] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2010] [Revised: 09/06/2010] [Accepted: 09/09/2010] [Indexed: 01/13/2023] Open
Abstract
Microinvasive carcinomas and high-grade intraepithelial neoplasms are commonly discovered within the fallopian tube of BRCA1 mutation carriers at the time of risk-reducing salpingo-oophorectomy, suggesting that many BRCA1-mutated ovarian carcinomas originate in tubal epithelium. We hypothesized that changes in gene expression profiles within the histologically normal fallopian tube epithelium of BRCA1 mutation carriers would overlap with the expression profiles in BRCA1-mutated ovarian carcinomas and represent a BRCA1 preneoplastic signature. Laser capture microdissection of frozen sections was used to isolate neoplastic cells or histologically normal fallopian tube epithelium, and expression profiles were generated on Affymetrix U133 Plus 2.0 gene expression arrays. Normal-risk controls were 11 women wild type for BRCA1 and BRCA2 (WT-FT). WT-FT were compared with histologically normal fallopian tube epithelium from seven women with deleterious BRCA1 mutations who had foci of at least intraepithelial neoplasm within their fallopian tube (B1-FTocc). WT-FT samples were also compared with 12 BRCA1 ovarian carcinomas (B1-CA). The comparison of WT-FT versus B1-FTocc resulted in 152 differentially expressed probe sets, and the comparison of WT-FT versus B1-CA resulted in 4079 differentially expressed probe sets. The BRCA1 preneoplastic signature was composed of the overlap between these two lists, which included 41 concordant probe sets. Genes in the BRCA1 preneoplastic signature included several known tumor suppressor genes such as CDKN1C and EFEMP1 and several thought to be important in invasion and metastasis such as E2F3. The expression of a subset of genes was validated with quantitative reverse transcription-polymerase chain reaction and immunohistochemistry.
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158
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Abouzeid H, Boisset G, Favez T, Youssef M, Marzouk I, Shakankiry N, Bayoumi N, Descombes P, Agosti C, Munier FL, Schorderet DF. Mutations in the SPARC-related modular calcium-binding protein 1 gene, SMOC1, cause waardenburg anophthalmia syndrome. Am J Hum Genet 2011; 88:92-8. [PMID: 21194680 DOI: 10.1016/j.ajhg.2010.12.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 12/01/2010] [Accepted: 12/08/2010] [Indexed: 11/19/2022] Open
Abstract
Waardenburg anophthalmia syndrome, also known as microphthalmia with limb anomalies, ophthalmoacromelic syndrome, and anophthalmia-syndactyly, is a rare autosomal-recessive developmental disorder that has been mapped to 10p11.23. Here we show that this disease is heterogeneous by reporting on a consanguineous family, not linked to the 10p11.23 locus, whose two affected children have a homozygous mutation in SMOC1. Knockdown experiments of the zebrafish smoc1 revealed that smoc1 is important in eye development and that it is expressed in many organs, including brain and somites.
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Affiliation(s)
- Hana Abouzeid
- IRO - Institute for Research in Ophthalmology, 1950 Sion, Switzerland; Jules-Gonin Eye Hospital, University of Lausanne, 1003 Lausanne
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159
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Tropoelastin and fibulin overexpression in the subepithelial connective tissue of human pterygium. Am J Ophthalmol 2011; 151:44-52. [PMID: 21094933 DOI: 10.1016/j.ajo.2010.07.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2010] [Revised: 07/21/2010] [Accepted: 07/23/2010] [Indexed: 11/22/2022]
Abstract
PURPOSE To evaluate possible changes in the collagen and elastic components of the subepithelial connective tissue of human pterygium. DESIGN Immunohistochemical study. METHODS Immunohistochemical staining using antitropoelastin, anti-fibulin-2, and anti-fibulin-3 antibodies was performed in 10 normal conjunctival and 20 pterygium specimens. Masson trichome staining also was performed to study subepithelial connective tissue. Sirius red staining was used to identify collagen type I and III components. Tropoelastin, fibulin-2, and fibulin-3 messenger ribonucleic acid (mRNA) expressions were analyzed in 9 conjunctival and 12 pterygium specimens by quantitative real-time polymerase chain reaction assay. RESULTS The subepithelial connective tissue and vessels were more predominant in pterygium compared with the normal conjunctival tissue. Amorphous subepithelial zones were observed in the areas of the pterygium tissue, but not in normal conjunctiva. Increased tropoelastin staining was seen in the pterygium tissue with areas of degenerative changes or immature formation of elastic fibers, as well an increase in tropoelastin mRNA, in contrast with fibulin-2 and fibulin-3 messenger levels. Fibulin-2 and fibulin-3 expression was colocalized in the subepithelial connective tissue and was distributed along blood and lymphatic vessels. Collagen type III, an immature form of collagen, was increased in the pathologic samples in association with a tissue remodeling process. CONCLUSIONS Elastin metabolism is dysregulated in the pathogenesis of human pterygium with tropoelastin, fibulin-2, and fibulin-3 overexpression in the subepithelial connective tissue.
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160
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Zhao C, Yasumura D, Li X, Matthes M, Lloyd M, Nielsen G, Ahern K, Snyder M, Bok D, Dunaief JL, LaVail MM, Vollrath D. mTOR-mediated dedifferentiation of the retinal pigment epithelium initiates photoreceptor degeneration in mice. J Clin Invest 2010; 121:369-83. [PMID: 21135502 DOI: 10.1172/jci44303] [Citation(s) in RCA: 254] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2010] [Accepted: 10/22/2010] [Indexed: 01/28/2023] Open
Abstract
Retinal pigment epithelial (RPE) cell dysfunction plays a central role in various retinal degenerative diseases, but knowledge is limited regarding the pathways responsible for adult RPE stress responses in vivo. RPE mitochondrial dysfunction has been implicated in the pathogenesis of several forms of retinal degeneration. Here we have shown that postnatal ablation of RPE mitochondrial oxidative phosphorylation in mice triggers gradual epithelium dedifferentiation, typified by reduction of RPE-characteristic proteins and cellular hypertrophy. The electrical response of the retina to light decreased and photoreceptors eventually degenerated. Abnormal RPE cell behavior was associated with increased glycolysis and activation of, and dependence upon, the hepatocyte growth factor/met proto-oncogene pathway. RPE dedifferentiation and hypertrophy arose through stimulation of the AKT/mammalian target of rapamycin (AKT/mTOR) pathway. Administration of an oxidant to wild-type mice also caused RPE dedifferentiation and mTOR activation. Importantly, treatment with the mTOR inhibitor rapamycin blunted key aspects of dedifferentiation and preserved photoreceptor function for both insults. These results reveal an in vivo response of the mature RPE to diverse stressors that prolongs RPE cell survival at the expense of epithelial attributes and photoreceptor function. Our findings provide a rationale for mTOR pathway inhibition as a therapeutic strategy for retinal degenerative diseases involving RPE stress.
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Affiliation(s)
- Chen Zhao
- Department of Genetics, Stanford University School of Medicine, Stanford, California 94305-5120, USA
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161
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Kahle JJ, Gulbahce N, Shaw CA, Lim J, Hill DE, Barabási AL, Zoghbi HY. Comparison of an expanded ataxia interactome with patient medical records reveals a relationship between macular degeneration and ataxia. Hum Mol Genet 2010; 20:510-27. [PMID: 21078624 PMCID: PMC3016911 DOI: 10.1093/hmg/ddq496] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Spinocerebellar ataxias 6 and 7 (SCA6 and SCA7) are neurodegenerative disorders caused by expansion of CAG repeats encoding polyglutamine (polyQ) tracts in CACNA1A, the alpha1A subunit of the P/Q-type calcium channel, and ataxin-7 (ATXN7), a component of a chromatin-remodeling complex, respectively. We hypothesized that finding new protein partners for ATXN7 and CACNA1A would provide insight into the biology of their respective diseases and their relationship to other ataxia-causing proteins. We identified 118 protein interactions for CACNA1A and ATXN7 linking them to other ataxia-causing proteins and the ataxia network. To begin to understand the biological relevance of these protein interactions within the ataxia network, we used OMIM to identify diseases associated with the expanded ataxia network. We then used Medicare patient records to determine if any of these diseases co-occur with hereditary ataxia. We found that patients with ataxia are at 3.03-fold greater risk of these diseases than Medicare patients overall. One of the diseases comorbid with ataxia is macular degeneration (MD). The ataxia network is significantly (P= 7.37 × 10−5) enriched for proteins that interact with known MD-causing proteins, forming a MD subnetwork. We found that at least two of the proteins in the MD subnetwork have altered expression in the retina of Ataxin-7266Q/+ mice suggesting an in vivo functional relationship with ATXN7. Together these data reveal novel protein interactions and suggest potential pathways that can contribute to the pathophysiology of ataxia, MD, and diseases comorbid with ataxia.
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Affiliation(s)
- Juliette J Kahle
- Department of Cellular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
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162
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Meyer KJ, Davis LK, Schindler EI, Beck JS, Rudd DS, Grundstad AJ, Scheetz TE, Braun TA, Fingert JH, Alward WL, Kwon YH, Folk JC, Russell SR, Wassink TH, Stone EM, Sheffield VC. Genome-wide analysis of copy number variants in age-related macular degeneration. Hum Genet 2010; 129:91-100. [PMID: 20981449 DOI: 10.1007/s00439-010-0904-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Accepted: 10/17/2010] [Indexed: 10/18/2022]
Abstract
Age-related macular degeneration (AMD) is a complex genetic disease, with many loci demonstrating appreciable attributable disease risk. Despite significant progress toward understanding the genetic and environmental etiology of AMD, identification of additional risk factors is necessary to fully appreciate and treat AMD pathology. In this study, we investigated copy number variants (CNVs) as potential AMD risk variants in a cohort of 400 AMD patients and 500 AMD-free controls ascertained at the University of Iowa. We used three publicly available copy number programs to analyze signal intensity data from Affymetrix GeneChip SNP Microarrays. CNVs were ranked based on prevalence in the disease cohort and absence from the control group; high interest CNVs were subsequently confirmed by qPCR. While we did not observe a single-locus "risk CNV" that could account for a major fraction of AMD, we identified several rare and overlapping CNVs containing or flanking compelling candidate genes such as NPHP1 and EFEMP1. These and other candidate genes highlighted by this study deserve further scrutiny as sources of genetic risk for AMD.
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Affiliation(s)
- Kacie J Meyer
- Interdisciplinary Genetics Program, University of Iowa, Iowa City, IA 52242, USA
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163
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Bandah-Rozenfeld D, Collin RWJ, Banin E, van den Born LI, Coene KLM, Siemiatkowska AM, Zelinger L, Khan MI, Lefeber DJ, Erdinest I, Testa F, Simonelli F, Voesenek K, Blokland EAW, Strom TM, Klaver CCW, Qamar R, Banfi S, Cremers FPM, Sharon D, den Hollander AI. Mutations in IMPG2, encoding interphotoreceptor matrix proteoglycan 2, cause autosomal-recessive retinitis pigmentosa. Am J Hum Genet 2010; 87:199-208. [PMID: 20673862 DOI: 10.1016/j.ajhg.2010.07.004] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 06/25/2010] [Accepted: 07/11/2010] [Indexed: 11/17/2022] Open
Abstract
Retinitis pigmentosa (RP) is a heterogeneous group of inherited retinal diseases caused by progressive degeneration of the photoreceptor cells. Using autozygosity mapping, we identified two families, each with three affected siblings sharing large overlapping homozygous regions that harbored the IMPG2 gene on chromosome 3. Sequence analysis of IMPG2 in the two index cases revealed homozygous mutations cosegregating with the disease in the respective families: three affected siblings of Iraqi Jewish ancestry displayed a nonsense mutation, and a Dutch family displayed a 1.8 kb genomic deletion that removes exon 9 and results in the absence of seven amino acids in a conserved SEA domain of the IMPG2 protein. Transient transfection of COS-1 cells showed that a construct expressing the wild-type SEA domain is properly targeted to the plasma membrane, whereas the mutant lacking the seven amino acids appears to be retained in the endoplasmic reticulum. Mutation analysis in ten additional index cases that were of Dutch, Israeli, Italian, and Pakistani origin and had homozygous regions encompassing IMPG2 revealed five additional mutations; four nonsense mutations and one missense mutation affecting a highly conserved phenylalanine residue. Most patients with IMPG2 mutations showed an early-onset form of RP with progressive visual-field loss and deterioration of visual acuity. The patient with the missense mutation, however, was diagnosed with maculopathy. The IMPG2 gene encodes the interphotoreceptor matrix proteoglycan IMPG2, which is a constituent of the interphotoreceptor matrix. Our data therefore show that mutations in a structural component of the interphotoreceptor matrix can cause arRP.
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Affiliation(s)
- Dikla Bandah-Rozenfeld
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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164
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Chavali VRM, Sommer JR, Petters RM, Ayyagari R. Identification of a promoter for the human C1Q-tumor necrosis factor-related protein-5 gene associated with late-onset retinal degeneration. Invest Ophthalmol Vis Sci 2010; 51:5499-507. [PMID: 20554618 DOI: 10.1167/iovs.10-5543] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The Complement-1q tumor necrosis factor-related protein 5 (C1QTNF5/CTRP5) gene is located in the 3' untranslated region of the Membrane Frizzled Related Protein (MFRP) gene, and these two genes are reported to be dicistronic. The authors examined the 5' upstream sequence of CTRP5 for the presence of a promoter regulating the expression of this gene. METHODS The sequence upstream of the translational start site of human CTRP5 (hCTRP5) was analyzed by Promoter Inspector software. A series of plasmids containing segments of hCTRP5 putative promoter sequence (-29 bp to -3.6 kb) upstream of the luciferase gene were generated. Cells were transiently transfected with these plasmids, and luciferase activity was measured. 5' RACE analysis was performed to determine the functional transcription start site. V5 tagged-pig CTRP5 (pCTRP5) gene, cloned downstream of the hCTRP5 putative promoter, was expressed in a human retinal cell line (ARPE-19) and a Chinese hamster ovary cell line (CHO-K1) to study the functionality of the putative promoter. RESULTS Bioinformatic analysis identified a putative promoter region between nt -1322 and +1 sequence of hCTRP5. 5' RACE analysis revealed the presence of the transcriptional start site (TSS) at 62 bp upstream of the start codon in the CTRP5. The 1.3-kb sequence of the hCTRP5 predicted promoter produced higher levels of luciferase activity, indicating the strength of the cloned CTRP5 promoter. The promoter sequence between nt -1322 bp to -29 bp upstream of the first ATG of CTRP5 was found to be essential for this promoter activity. The predicted hCTRP5 promoter was found to control the expression of V5-tagged pCTRP5 and nuclear GFP, indicating that the promoter was functional. CONCLUSIONS This study revealed the presence of a functional promoter for the CTRP5 gene located 5' of its start site. Understanding the regulation of CTRP5 gene transcription may provide insights into the possible role of CTRP5 in the retina and the pathology underlying late-onset retinal degeneration caused by mutations in this gene. In addition, these studies will determine whether CTRP5 and MFRP are functionally dicistronic.
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Affiliation(s)
- Venkata R M Chavali
- Department of Ophthalmology, University of California San Diego, La Jolla, California, USA
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165
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Samuels IS, Sturgill GM, Grossman GH, Rayborn ME, Hollyfield JG, Peachey NS. Light-evoked responses of the retinal pigment epithelium: changes accompanying photoreceptor loss in the mouse. J Neurophysiol 2010; 104:391-402. [PMID: 20484527 DOI: 10.1152/jn.00088.2010] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Mutations in genes expressed in the retinal pigment epithelium (RPE) underlie a number of human inherited retinal disorders that manifest with photoreceptor degeneration. Because light-evoked responses of the RPE are generated secondary to rod photoreceptor activity, RPE response reductions observed in human patients or animal models may simply reflect decreased photoreceptor input. The purpose of this study was to define how the electrophysiological characteristics of the RPE change when the complement of rod photoreceptors is decreased. To measure RPE function, we used an electroretinogram (dc-ERG)-based technique. We studied a slowly progressive mouse model of photoreceptor degeneration (Prph(Rd2/+)), which was crossed onto a Nyx(nob) background to eliminate the b-wave and most other postreceptoral ERG components. On this background, Prph(Rd2/+) mice display characteristic reductions in a-wave amplitude, which parallel those in slow PIII amplitude and the loss of rod photoreceptors. At 2 and 4 mo of age, the amplitude of each dc-ERG component (c-wave, fast oscillation, light peak, and off response) was larger in Prph(Rd2/+) mice than predicted by rod photoreceptor activity (Rm(P3)) or anatomical analysis. At 4 mo of age, the RPE in Prph(Rd2/+) mice showed several structural abnormalities including vacuoles and swollen, hypertrophic cells. These data demonstrate that insights into RPE function can be gained despite a loss of photoreceptors and structural changes in RPE cells and, moreover, that RPE function can be evaluated in a broader range of mouse models of human retinal disease.
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Affiliation(s)
- Ivy S Samuels
- Research Service, Louis Stokes Cleveland VA Medical Center, Cleveland, Ohio 44106, USA.
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166
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Diagnostic and therapeutic challenges. Retina 2010; 31:413-8. [PMID: 20458258 DOI: 10.1097/iae.0b013e3181dc58db] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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167
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Abstract
Age-related macular degeneration (AMD) is a complex disorder of the eye and the third leading cause of blindness worldwide. With a multifactorial etiology, AMD results in progressive loss of central vision affecting the macular region of the eye in elderly. While the prevalence is relatively higher in the Caucasian populations, it has gradually become a major public health issue among the non-Caucasian populations (including Indians) as well due to senescence, rapidly changing demographics and life-style factors. Recent genome-wide association studies (GWAS) on large case-control cohorts have helped in mapping genes in the complement cascade that are involved in the regulation of innate immunity with AMD susceptibility. Genes involved with mitochondrial oxidative stress and extracellular matrix regulation also play a role in AMD pathogenesis. Majority of the associations observed in complement (CFH, CFB, C2 and C3) and other (ARMS2 and HTRA1) genes have been replicated in diverse populations worldwide. Gene-gene (CFH with ARMS2 and HTRA1) interactions and correlations with environmental traits (smoking and body mass index) have been established as significant covariates in AMD pathology. In this review, we have provided an overview on the underlying molecular genetic mechanisms in AMD worldwide and highlight the AMD-associated-candidate genes and their potential role in disease pathogenesis.
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168
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En-lin S, Sheng-guo C, Hua-qiao W. The expression of EFEMP1 in cervical carcinoma and its relationship with prognosis. Gynecol Oncol 2010; 117:417-22. [PMID: 20378157 DOI: 10.1016/j.ygyno.2009.12.016] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2009] [Revised: 12/08/2009] [Accepted: 12/10/2009] [Indexed: 11/28/2022]
Abstract
OBJECTIVE The study was to explore the role of EFEMP1 protein in angiogenesis and its relationship with prognosis of cervical carcinoma. METHODS EFEMP1 expression was evaluated by immunohistochemistry. The microvascular density (MVD) was detected with CD34 staining, and VEGF mRNA expression was evaluated by hybridization in situ. The associations of EFEMP1 with clinicopathologic characteristics, MVD, VEGF mRNA and overall survival were studied. RESULTS EFEMP1 expression was positively correlated with MVD and VEGF mRNA, and its overexpression was found to be significantly associated with lymph node metastasis, vascular invasion and poor survival. Multivariate analysis showed that EFEMP1 overexpression was independently related to poor prognosis of cervical cancer. CONCLUSIONS EFEMP1 promotes angiogenesis and associates with lymph node metastasis, vascular invasion and poor prognosis of cervical carcinoma. The current study shows that EFEMP1 may be a useful prognostic factor for patients with cervical carcinoma.
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Affiliation(s)
- Song En-lin
- Biomedical Engineering Center, Department of Anatomy, the Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, Guangdong 510080, China
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169
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Yanagisawa H, Davis EC. Unraveling the mechanism of elastic fiber assembly: The roles of short fibulins. Int J Biochem Cell Biol 2010; 42:1084-93. [PMID: 20236620 DOI: 10.1016/j.biocel.2010.03.009] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Revised: 02/20/2010] [Accepted: 03/08/2010] [Indexed: 12/29/2022]
Abstract
Evolution of elastic fibers is associated with establishment of the closed circulation system. Primary roles of elastic fibers are to provide elasticity and recoiling to tissues and organs and to maintain the structural integrity against mechanical strain over a lifetime. Elastic fibers are comprised of an insoluble elastin core and surrounding mantle of microfibrils. Elastic fibers are formed in a regulated, stepwise manner, which includes the formation of a microfibrillar scaffold, deposition and integration of tropoelastin monomers into the scaffold, and cross-linking of the monomers to form an insoluble, functional polymer. In recent years, an increasing number of glycoproteins have been identified and shown to be located on or surrounding elastic fibers. Among them, the short fibulins-3, -4 and -5 particularly drew attention because of their potent elastogenic activity. Fibulins-3, -4 and -5 are characterized by tandem repeats of calcium binding EGF-like motifs and a C-terminal fibulin module, which is conserved throughout fibulin family members. Initial biochemical characterization and gene expression studies predicted that fibulins might be involved in structural support and/or matrix-cell interactions. Recent analyses of short fibulin knockout mice have revealed their critical roles in elastic fiber development in vivo. We review recent findings on the elastogenic functions of short fibulins and discuss the molecular mechanism underlying their activity in vitro and in vivo.
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Affiliation(s)
- Hiromi Yanagisawa
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9148, USA.
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170
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Ramkumar HL, Zhang J, Chan CC. Retinal ultrastructure of murine models of dry age-related macular degeneration (AMD). Prog Retin Eye Res 2010; 29:169-90. [PMID: 20206286 DOI: 10.1016/j.preteyeres.2010.02.002] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Age-related macular degeneration (AMD) is the most prevalent form of irreversible blindness worldwide in the elderly population. The pathology of dry AMD consists of macular degeneration of photoreceptors and the RPE, lipofuscin (A2E) accumulation, and drusen formation. Mice have been widely used for generating models that simulate human AMD features for investigating the pathogenesis, treatment and prevention of the disease. Although the mouse has no macula, focal atrophy of photoreceptors and RPE, lipofuscin accumulation, and increased A2E can develop in aged mouse eyes. However, drusen are rarely seen in mice because of their simpler Bruch's membrane and different process of lipofuscin extrusion compared with humans. Thus, analyzing basal deposits at the ultrastructural level and understanding the ultrastructural pathologic differences between various mouse AMD models are critical to comprehending the significance of research findings and response to possible therapeutic options for dry AMD. Based on the multifactorial pathogenesis of AMD, murine dry AMD models can be classified into three groups. First, genetically engineered mice that target genes related to juvenile macular dystrophies are the most common models, and they include abcr(-/-) (Stargardt disease), transgenic ELOVL4 (Stargardt-3 dominant inheritary disease), Efemp1(R345W/R345W) (Doyne honeycomb retinal dystrophy), and Timp3(S156C/S156C) (Sorsby fundus dystrophy) mice. Other murine models target genes relevant to AMD, including inflammatory genes such as Cfh(-/-), Ccl2(-/-), Ccr2(-/-), Cx3cr1(-/-), and Ccl2(-/-)/cx3cr1(-/-), oxidative stress associated genes such as Sod1(-/-) and Sod2 knockdown, metabolic pathway genes such as neprilysin(-/-) (amyloid beta), transgenic mcd/mcd (cathepsin D), Cp(-/-)/Heph(-/Y) (ferroxidase ceruloplasmin/hepaestin, iron metabolism), and transgenic ApoE4 on high fat and high cholesterol diet (lipid metabolism). Second, mice have also been immunologically manipulated by immunization with carboxyethylpyrrole (CEP), an oxidative fragment of DHA found in drusen, and found to present with dry AMD features. Third, natural mouse strains such as arrd2/arrd2 (Mdm gene mutation) and the senescence accelerated mice (SAM) spontaneously develop features of dry AMD like photoreceptor atrophy and thickening of Bruch's membrane. All the aforementioned models develop retinal lesions with various features that simulate dry AMD lesions: focal photoreceptor degeneration, abnormal RPE with increased lipofuscin, basal infolding, decreased melanosomes and degeneration. However, Bruch's membrane changes are less common. Most mice develop retinal lesions at an older age (6-24 months, depending on the models), while the Ccl2(-/-)/cx3cr1(-/-) mice develop lesions by 4-6 weeks. Although murine models present various degrees of retinal and/or RPE degeneration, classical drusen is extremely rare. Using electron microscopy, small drusenoid deposits are found between RPE and Bruch's membrane in a few models including Efemp1(R345W/R345W), Ccl2(-/-)/cx3cr1(-/-), neprilysin(-/-), transgenic mcd/mcd, and ApoE4 transgenic mice on a high fat diet. High A2E levels are measured in the retinas of abcr(-/-), transgenic ELOVL4, and Ccl2(-/-)/cx3cr1(-/-) mice. In summary, murine models provide useful tools for studying AMD pathogenesis and evaluating novel therapies for this disease. This review compares the major dry AMD murine models and discusses retinal pathology at the ultrastructural level.
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Affiliation(s)
- Hema L Ramkumar
- Immunopathology Section, Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, MD 20892-1857, USA
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171
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Brew K, Nagase H. The tissue inhibitors of metalloproteinases (TIMPs): an ancient family with structural and functional diversity. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:55-71. [PMID: 20080133 DOI: 10.1016/j.bbamcr.2010.01.003] [Citation(s) in RCA: 889] [Impact Index Per Article: 63.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Revised: 12/17/2009] [Accepted: 01/04/2010] [Indexed: 12/14/2022]
Abstract
Tissue inhibitors of metalloproteinases (TIMPs) are widely distributed in the animal kingdom and the human genome contains four paralogous genes encoding TIMPs 1 to 4. TIMPs were originally characterized as inhibitors of matrix metalloproteinases (MMPs), but their range of activities has now been found to be broader as it includes the inhibition of several of the disintegrin-metalloproteinases, ADAMs and ADAMTSs. TIMPs are therefore key regulators of the metalloproteinases that degrade the extracellular matrix and shed cell surface molecules. Structural studies of TIMP-MMP complexes have elucidated the inhibition mechanism of TIMPs and the multiple sites through which they interact with target enzymes, allowing the generation of TIMP variants that selectively inhibit different groups of metalloproteinases. Engineering such variants is complicated by the fact that TIMPs can undergo changes in molecular dynamics induced by their interactions with proteases. TIMPs also have biological activities that are independent of metalloproteinases; these include effects on cell growth and differentiation, cell migration, anti-angiogenesis, anti- and pro-apoptosis, and synaptic plasticity. Receptors responsible for some of these activities have been identified and their signaling pathways have been investigated. A series of studies using mice with specific TIMP gene deletions has illuminated the importance of these molecules in biology and pathology.
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Affiliation(s)
- Keith Brew
- Department of Basic Science, College of Biomedical Science, Florida Atlantic University, Boca Raton, FL 33431, USA
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172
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Wakabayashi T, Matsumine A, Nakazora S, Hasegawa M, Iino T, Ota H, Sonoda H, Sudo A, Uchida A. Fibulin-3 negatively regulates chondrocyte differentiation. Biochem Biophys Res Commun 2009; 391:1116-21. [PMID: 20005202 DOI: 10.1016/j.bbrc.2009.12.034] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 12/08/2009] [Indexed: 01/29/2023]
Abstract
Fibulin-3 is a member of the fibulin family that has been newly recognized as extracellular matrix proteins. We assessed the effects of fibulin-3 overexpression on chondrocyte differentiation using the clonal murine cell line ATDC5. The ATDC5-FBLN3 stably expressing fibulin-3 protein was spindle-shaped cell compared to the ATDC5-mock with plump cell. The cell growth in the ATDC5-FBLN3 was accelerated in comparison to that in the ATDC5-mock. The ATDC5-FBLN3 was not stained by Alcian blue, nor was there any cartilage aggregate formed after the induction of chondrogenic differentiation. The expression of type II collagen, aggrecan, and type X collagen was completely suppressed in ATDC5-FBLN3 even after the induction of differentiation. The overexpression of fibulin-3 reduced the expression of Sox5 and Sox6, while it maintained the expression of Sox9. These findings suggest that fibulin-3 may play an important role as a negative regulator of chondrocyte differentiation.
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Affiliation(s)
- Toru Wakabayashi
- Department of Orthopaedic Surgery, Mie University Graduate School of Medicine, 2-174 Edobashi, Tsu-city, Mie 514-8507, Japan
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173
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Mellough CB, Steel DHW, Lako M. Genetic basis of inherited macular dystrophies and implications for stem cell therapy. Stem Cells 2009; 27:2833-45. [PMID: 19551904 PMCID: PMC2962903 DOI: 10.1002/stem.159] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2009] [Accepted: 06/11/2009] [Indexed: 12/25/2022]
Abstract
Untreatable hereditary macular dystrophy (HMD) presents a major burden to society in terms of the resulting patient disability and the cost to the healthcare provision system. HMD results in central vision loss in humans sufficiently severe for blind registration, and key issues in the development of therapeutic strategies to target these conditions are greater understanding of the causes of photoreceptor loss and the development of restorative procedures. More effective and precise analytical techniques coupled to the development of transgenic models of disease have led to a prolific growth in the identification and our understanding of the genetic mutations that underly HMD. Recent successes in driving differentiation of pluripotent cells towards specific somatic lineages have led to the development of more efficient protocols that can yield enriched populations of a desired phenotype. Retinal pigmented epithelial cells and photoreceptors derived from these are some of the most promising cells that may soon be used in the treatment of specific HMD, especially since rapid developments in the field of induced pluripotency have now set the stage for the production of patient-derived stem cells that overcome the ethical and methodological issues surrounding the use of embryonic derivatives. In this review we highlight a selection of HMD which appear suitable candidates for combinatorial restorative therapy, focusing specifically on where those photoreceptor loss occurs. This technology, along with increased genetic screening, opens up an entirely new pathway to restore vision in patients affected by HMD.
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Affiliation(s)
- Carla B Mellough
- Institute of Human Genetics andInternational Centre for LifeNewcastle Upon Tyne, United Kingdom
| | - David HW Steel
- Sunderland Eye InfirmaryQueen Alexandra Road, Sunderland, Tyne and Wear, United Kingdom
| | - Majlinda Lako
- North East Stem Cell Institute, Newcastle University, International Centre for LifeNewcastle Upon Tyne, United Kingdom
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174
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Differential expression of fibulins in the uterosacral ligaments of women with uterine prolapse. Arch Gynecol Obstet 2009; 282:389-94. [DOI: 10.1007/s00404-009-1262-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Accepted: 10/08/2009] [Indexed: 01/21/2023]
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175
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Fibulin-4 conducts proper elastogenesis via interaction with cross-linking enzyme lysyl oxidase. Proc Natl Acad Sci U S A 2009; 106:19029-34. [PMID: 19855011 DOI: 10.1073/pnas.0908268106] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Great arteries, as well as lungs and skin, contain elastic fibers as important components to maintain their physiological functions. Although recent studies have revealed that a glycoprotein fibulin-4 (FBLN4) is indispensable for the assembly of mature elastic fibers, it remains to be elucidated how FBLN4 takes part in elastogenesis. Here, we report a dose-dependent requirement for FBLN4 in the development of the elastic fibers in arteries, and a specific role of FBLN4 in recruiting the elastin-cross-linking enzyme, lysyl oxidase (LOX). Reduced expression of Fbln4, which was achieved with a smooth muscle-specific Cre-mediated gene deletion, caused arterial stiffness. Electron-microscopic examination revealed disorganized thick elastic laminae with aberrant deposition of elastin. Aneurysmal dilation of the ascending aorta was found when the Fbln4 expression level was reduced to an even lower level, whereas systemic Fbln4 null mice died perinatally from rupture of the diaphragm. We also found a specific interaction between FBLN4 and the propeptide of LOX, which efficiently promotes assembly of LOX onto tropoelastin. These data suggest a mechanism of elastogenesis, in which a sufficient amount of FBLN4 is essential for tethering LOX to tropoelastin to facilitate cross-linking.
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176
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Takeuchi T, Hayashi T, Bedell M, Zhang K, Yamada H, Tsuneoka H. A novel haplotype with the R345W mutation in the EFEMP1 gene associated with autosomal dominant drusen in a Japanese family. Invest Ophthalmol Vis Sci 2009; 51:1643-50. [PMID: 19850834 DOI: 10.1167/iovs.09-4497] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
PURPOSE To describe ophthalmic and molecular genetic findings in a family of Japanese patients with Malattia leventinese (ML)/Doyne honeycomb retinal dystrophy (DHRD), also known as autosomal dominant drusen. METHODS Four patients with ML/DHRD, including a 42-year-old female proband, were ascertained. The proband underwent complete ophthalmic examinations, including fundus and electrodiagnostic investigations, and Humphrey visual field (VF) perimetry. Mutation screening of the EFEMP1 gene and haplotype analysis were performed in the family, an Indian ML/DHRD family, and a branch of 1 of 39 ML/DHRD families in the United States, in which all affected patients shared a common haplotype. RESULTS A heterozygous missense mutation (p.R345W) was identified in all four Japanese patients and in affected patients of the other two families. This mutation was the only mutation that has been exclusively found in the gene. The disease haplotype in the Japanese family was different from those of the other two families. Clinically, central retinas were prominently affected in the proband and her mother, and subsequently the proband developed subfoveal choroidal neovascularization in the left eye, whereas her younger sister with the mutation, who was asymptomatic, exhibited only fine macular drusen. Long-term follow-up of Humphrey VF and multifocal-electroretinography (mfERG) in the proband also revealed progressive attenuation of macular function in the right eye. CONCLUSIONS This is the first report to describe a Japanese family with variable expressivity of ML/DHRD, in which a novel disease haplotype was identified. Humphrey VF and mfERG testing may be helpful in determining the long-term outcome of macular function.
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Affiliation(s)
- Tomokazu Takeuchi
- Department of Ophthalmology, he Jikei University School of Medicine, Tokyo, Japan.
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177
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Zhang Y, Marmorstein LY. Focus on molecules: fibulin-3 (EFEMP1). Exp Eye Res 2009; 90:374-5. [PMID: 19799900 DOI: 10.1016/j.exer.2009.09.018] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Accepted: 09/22/2009] [Indexed: 12/01/2022]
Affiliation(s)
- Youwen Zhang
- Department of Ophthalmology and Vision Science, University of Arizona, 655 N Alvernon Way, Tucson, AZ 85711, USA
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178
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Expressed sequence tag analysis of adult human optic nerve for NEIBank: identification of cell type and tissue markers. BMC Neurosci 2009; 10:121. [PMID: 19778450 PMCID: PMC2762980 DOI: 10.1186/1471-2202-10-121] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2008] [Accepted: 09/24/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The optic nerve is a pure white matter central nervous system (CNS) tract with an isolated blood supply, and is widely used in physiological studies of white matter response to various insults. We examined the gene expression profile of human optic nerve (ON) and, through the NEIBANK online resource, to provide a resource of sequenced verified cDNA clones. An un-normalized cDNA library was constructed from pooled human ON tissues and was used in expressed sequence tag (EST) analysis. Location of an abundant oligodendrocyte marker was examined by immunofluorescence. Quantitative real time polymerase chain reaction (qRT-PCR) and Western analysis were used to compare levels of expression for key calcium channel protein genes and protein product in primate and rodent ON. RESULTS Our analyses revealed a profile similar in many respects to other white matter related tissues, but significantly different from previously available ON cDNA libraries. The previous libraries were found to include specific markers for other eye tissues, suggesting contamination. Immune/inflammatory markers were abundant in the new ON library. The oligodendrocyte marker QKI was abundant at the EST level. Immunofluorescence revealed that this protein is a useful oligodendrocyte cell-type marker in rodent and primate ONs. L-type calcium channel EST abundance was found to be particularly low. A qRT-PCR-based comparative mammalian species analysis reveals that L-type calcium channel expression levels are significantly lower in primate than in rodent ON, which may help account for the class-specific difference in responsiveness to calcium channel blocking agents. Several known eye disease genes are abundantly expressed in ON. Many genes associated with normal axonal function, mRNAs associated with axonal transport, inflammation and neuroprotection are observed. CONCLUSION We conclude that the new cDNA library is a faithful representation of human ON and EST data provide an initial overview of gene expression patterns in this tissue. The data provide clues for tissue-specific and species-specific properties of human ON that will help in design of therapeutic models.
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179
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Vukovic J, Marmorstein LY, McLaughlin PJ, Sasaki T, Plant GW, Harvey AR, Ruitenberg MJ. Lack of fibulin-3 alters regenerative tissue responses in the primary olfactory pathway. Matrix Biol 2009; 28:406-15. [DOI: 10.1016/j.matbio.2009.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2009] [Revised: 06/02/2009] [Accepted: 06/02/2009] [Indexed: 01/16/2023]
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180
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181
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Diagnostic and therapeutic challenges. Retina 2009; 29:708-14. [PMID: 19430282 DOI: 10.1097/iae.0b013e3181a0bde9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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182
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Parry DA, Toomes C, Bida L, Danciger M, Towns KV, McKibbin M, Jacobson SG, Logan CV, Ali M, Bond J, Chance R, Swendeman S, Daniele LL, Springell K, Adams M, Johnson CA, Booth AP, Jafri H, Rashid Y, Banin E, Strom TM, Farber DB, Sharon D, Blobel CP, Pugh EN, Pierce EA, Inglehearn CF. Loss of the metalloprotease ADAM9 leads to cone-rod dystrophy in humans and retinal degeneration in mice. Am J Hum Genet 2009; 84:683-91. [PMID: 19409519 PMCID: PMC2681008 DOI: 10.1016/j.ajhg.2009.04.005] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 04/06/2009] [Accepted: 04/09/2009] [Indexed: 01/28/2023] Open
Abstract
Cone-rod dystrophy (CRD) is an inherited progressive retinal dystrophy affecting the function of cone and rod photoreceptors. By autozygosity mapping, we identified null mutations in the ADAM metallopeptidase domain 9 (ADAM9) gene in four consanguineous families with recessively inherited early-onset CRD. We also found reduced photoreceptor responses in Adam9 knockout mice, previously reported to be asymptomatic. In 12-month-old knockout mice, photoreceptors appear normal, but the apical processes of the retinal pigment epithelium (RPE) cells are disorganized and contact between photoreceptor outer segments (POSs) and the RPE apical surface is compromised. In 20-month-old mice, there is clear evidence of progressive retinal degeneration with disorganized POS and thinning of the outer nuclear layer (ONL) in addition to the anomaly at the POS-RPE junction. RPE basal deposits and macrophages were also apparent in older mice. These findings therefore not only identify ADAM9 as a CRD gene but also identify a form of pathology wherein retinal disease first manifests at the POS-RPE junction.
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Abstract
The retinal pigment epithelium (RPE) is a cellular monolayer between the choriocapillaris and the photoreceptors which controls the uptake of nutrients by the retina and the disposal of shed photoreceptor outer segments from the retina. The RPE is responsible for a continuous supply of rhodopsin by the retinol cycle and blocking of light by its pigmentation to minimize light-induced oxidation of retinal lipids and proteins. Proteins encoded by genes in which mutations are responsible for hereditary disorders of the retina and the RPE are involved in all these functions. In this article these genes and disorders are reviewed in the context of a functional network.
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Affiliation(s)
- M N Preising
- Klinik und Poliklinik für Augenheilkunde Justus-Liebig-Universität Giessen, Universitätsklinikum Giessen und Marburg GmbH, Standort Giessen, Giessen, Deutschland.
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184
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Vukovic J, Ruitenberg MJ, Roet K, Franssen E, Arulpragasam A, Sasaki T, Verhaagen J, Harvey AR, Busfield SJ, Plant GW. The glycoprotein fibulin-3 regulates morphology and motility of olfactory ensheathing cellsin vitro. Glia 2009; 57:424-43. [DOI: 10.1002/glia.20771] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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185
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Seeliger H, Camaj P, Ischenko I, Kleespies A, De Toni EN, Thieme SE, Blum H, Assmann G, Jauch KW, Bruns CJ. EFEMP1 expression promotes in vivo tumor growth in human pancreatic adenocarcinoma. Mol Cancer Res 2009; 7:189-98. [PMID: 19208748 DOI: 10.1158/1541-7786.mcr-08-0132] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The progression of pancreatic cancer is dependent on local tumor growth, angiogenesis, and metastasis. EFEMP1, a recently discovered member of the fibulin family, was characterized with regard to these key elements of pancreatic cancer progression. Differential gene expression was assessed by mRNA microarray hybridization in FG human pancreatic adenocarcinoma cells and L3.6pl cells, a highly metastatic variant of FG. In vivo orthotopic tumor growth of EFEMP1-transfected FG cells was examined in nude mice. To assess the angiogenic properties of EFEMP1, vascular endothelial growth factor (VEGF) production of tumor cells, endothelial cell proliferation and migration, and tumor microvessel density were analyzed in response to EFEMP1. Further, tumor cell apoptosis, cell cycle progression, and resistance to cytotoxic agents were quantitated by propidium iodide staining and flow cytometry. In microarray hybridization, EFEMP1 was shown to be significantly up-regulated in L3.6pl cells compared with FG cells. Concordantly, EFEMP1 transfection of FG cells stimulated orthotopic and metastatic tumor growth in vivo. EFEMP1 expression resulted in a stimulation of VEGF production by tumor cells and an increased number of CD31-positive microvessels. Endothelial cell proliferation and migration were not altered by EFEMP1, indicating an indirect angiogenic effect. Further, EFEMP1 expression decreased apoptosis and promoted cell cycle progression in response to serum starvation or exposure to gemcitabine, 5-fluorouracil, and irinotecan. EFEMP1 has protumorigenic effects on pancreatic cancer in vivo and in vitro mediated by VEGF-driven angiogenesis and antiapoptotic mechanisms. Hence, EFEMP1 is a promising candidate for assessing prognosis and individualizing therapy in a clinical tumor setting.
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Affiliation(s)
- Hendrik Seeliger
- Munich University Medical Center, Department of Surgery, Munich, Germany.
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186
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Sherwin JC, Hewitt AW, Ruddle JB, Mackey DA. Genetic isolates in ophthalmic diseases. Ophthalmic Genet 2008; 29:149-61. [PMID: 19005985 DOI: 10.1080/13816810802334341] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In recent years, noteworthy gains have been made in unravelling the genetic contribution to some complex ocular diseases, principally age-related macular degeneration. Yet, a relatively poor understanding of the genetic aetiology for many other heritable blinding diseases, such as glaucoma, keratoconus and myopia, remains. Genetic isolates, populations with varying degrees of geographical or cultural seclusion, provide an effective means for investigating the molecular mechanisms involved in human diseases. This is particularly true for rare diseases in which founded alleles can be rapidly driven to a high frequency due to restriction of gene flow in the population. Recent success in complex gene mapping has resulted from the widened linkage disequilibrium (LD) in the genome of genetically isolated populations. An improved understanding of the predisposing genetic risk factors allows for enhanced screening modalities and paves the foundations for the translation of genomic technology into the clinic. This review focuses on the role population isolates have had in the investigation of genes underlying complex eye diseases and discusses their likely usefulness given the expansion of large-scale case-control association studies.
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Affiliation(s)
- Justin C Sherwin
- Department of Ophthalmology, Centre for Eye Research Australia, University of Melbourne, elbourne, Australia
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Forrester JV. Privilege revisited: an evaluation of the eye's defence mechanisms. Eye (Lond) 2008; 23:756-66. [PMID: 18989350 DOI: 10.1038/eye.2008.259] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Immune privilege has been considered for many years to be an interesting phenomenon associated with certain specialised tissues such as the eye and the brain. In recent years however, it has become clear that the active and passive mechanisms which underpin immune privilege are in fact a form of tissue-based immunological tolerance, perhaps of equal importance in providing defence against antigenic attack as the well established mechanisms based on the thymus (central tolerance) and circulating regulatory cells (peripheral tolerance). It would appear that each tissue possesses a degree of intrinsic immunological resistance which varies depending on the tissues and provides some degree of protection. In some tissues, such as the eye, this is protection from 'danger' has been developed to a high level of sophistication, but at a price. The mechanisms involved are presented in his lecture.
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Affiliation(s)
- J V Forrester
- Department of Ophthalmology, University of Aberdeen, Institute of Medical Sciences, Aberdeen, Scotland, UK.
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188
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Retinal microstructure in patients with EFEMP1 retinal dystrophy evaluated by Fourier domain OCT. Eye (Lond) 2008; 23:480-3. [PMID: 18791549 DOI: 10.1038/eye.2008.251] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVES To investigate retinal microstructure of patients affected with malattia leventinese (MLVT) and mutation in the EFEMP1 gene using high-resolution optical coherence tomography (OCT). METHODS Patients diagnosed with MLVT received a comprehensive eye exam, full-field and multifocal electroretinogram testing and imaging with a high-resolution Fourier domain OCT (Fd-OCT, UC Davis Medical Center, Davis, USA; axial resolution: 4.5 microm, acquisition speed: 9 frames s(-1), 1000 A scans s(-1)) combined with a flexible scanning head (Bioptigen Inc. Durham, NC, USA). RESULTS Two related patients aged 30 and 60 years, with MLVT and identified c.R345W mutation in the EFEMP1 gene, were tested. Mother and daughter showed a variable phenotype with reduced vision function in the younger patient, whereas the mother had a 'form frustre'. Fd-OCT revealed extensive or focal sub-retinal pigment epithelium (RPE) deposits, separation of RPE and Bruch's membrane, and disruption of the photoreceptor outer and inner segment layers. No outer retinal changes were visible outside areas with sub-RPE deposits. CONCLUSION Retinal structure in EFEMP1 retinal dystrophy is reflected by morphological changes within the RPE/Bruch's membrane complex with accumulation of sub-RPE material associated with disrupted photoreceptor integrity. The pattern of microstructural retinal abnormalities is similar but with a different extent in patients with variable phenotypes.
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189
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Barbazetto IA, Yannuzzi NA, Klais CM, Merriam JE, Zernant J, Peiretti E, Yannuzzi LA, Allikmets R. Pseudo-vitelliform macular detachment and cuticular drusen: exclusion of 6 candidate genes. Ophthalmic Genet 2008; 28:192-7. [PMID: 18161617 DOI: 10.1080/13816810701538596] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
PURPOSE The etiology and genetic cause of pseudo-vitelliform macular detachment with cuticular drusen (PVMD/CD) are unknown; nor is it clear if this phenotype represents a separate disease entity, or is a sub-phenotype of disorders with overlapping clinical presentation. To answer this question, we screened a cohort of patients affected with PVMD/CD for variation in six plausible candidate genes (ABCA4, VMD2, TIMP-3, peripherin/RDS, fibulin 5 (FIBL5) and complement factor H (CFH)) associated with diseases of overlapping phenotypes. METHODS Twenty-eight patients, diagnosed with pseudo-vitelliform macular detachment and cuticular drusen, were evaluated by clinical examination, fundus photography, fluorescein angiography and autofluorescence imaging. DNA from all study subjects were screened for variants in the ABCA4, VMD2, TIMP-3, peripherin/RDS, FIBL5 and CFH genes by a combination of DHPLC, array screening and direct sequencing. RESULTS All patients presented with cuticular drusen; pseudo-vitelliform detachment was seen in 21 cases, while atrophic changes following regression of the detachment were seen in the remaining 7 subjects. Visual acuity ranged from 20/20 to CF. The screening revealed an I32V mutation in peripherin/RDS in one patient and 2ABCA4 variants, T897I and G1961E, in 2 more patients. No amino acid-altering variants were detected in VMD2, TIMP-3, and FIBL5 genes. The frequency of the CFH Y402H variant in this cohort corresponded to that detected in the general population. CONCLUSIONS Screening of 6 candidate genes detected possibly disease-associated mutations in only 3/28 (10.7%) of patients presenting with PVMD/CD, eliminating these genes as causal for this phenotype.
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Affiliation(s)
- Irene A Barbazetto
- Department of Ophthalmology, Columbia University, New York, New York 10032, USA
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190
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Abstract
Elastic fibers provide recoil to tissues that undergo repeated stretch, such as the large arteries and lung. These large extracellular matrix (ECM) structures contain numerous components, and our understanding of elastic fiber assembly is changing as we learn more about the various molecules associated with the assembly process. The main components of elastic fibers are elastin and microfibrils. Elastin makes up the bulk of the mature fiber and is encoded by a single gene. Microfibrils consist mainly of fibrillin, but also contain or associate with proteins such as microfibril associated glycoproteins (MAGPs), fibulins, and EMILIN-1. Microfibrils were thought to facilitate alignment of elastin monomers prior to cross-linking by lysyl oxidase (LOX). We now know that their role, as well as the overall assembly process, is more complex. Elastic fiber formation involves elaborate spatial and temporal regulation of all of the involved proteins and is difficult to recapitulate in adult tissues. This report summarizes the known interactions between elastin and the microfibrillar proteins and their role in elastic fiber assembly based on in vitro studies and evidence from knockout mice. We also propose a model of elastic fiber assembly based on the current data that incorporates interactions between elastin, LOXs, fibulins and the microfibril, as well as the pivotal role played by cells in structuring the final functional fiber.
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Affiliation(s)
- Jessica E Wagenseil
- Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
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191
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Expression and Cell Compartmentalization of EFEMP1, a Protein Associated with Malattia Leventinese. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008. [DOI: 10.1007/978-0-387-74904-4_32] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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192
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Stone EM. Leber congenital amaurosis - a model for efficient genetic testing of heterogeneous disorders: LXIV Edward Jackson Memorial Lecture. Am J Ophthalmol 2007; 144:791-811. [PMID: 17964524 DOI: 10.1016/j.ajo.2007.08.022] [Citation(s) in RCA: 212] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Revised: 07/26/2007] [Accepted: 08/07/2007] [Indexed: 01/24/2023]
Abstract
PURPOSE To critically evaluate our experience in molecular testing of Leber congenital amaurosis (LCA) and to use this information to devise a general approach to heterogeneous recessive disorders. Careful clinical and molecular characterization of large cohorts of patients affected with inherited eye diseases will be an essential step in the development of effective therapy for these diseases, especially when the therapy involves gene replacement. DESIGN A molecular genetic case-control study. METHODS Six hundred forty-two unrelated individuals with the clinical diagnosis of LCA and 200 unrelated control individuals were screened for disease-causing sequence variations in eight genes using various combinations of single-strand conformational polymorphism analysis (SSCP), automated DNA sequencing, multiplex allele-specific ligation analysis (SNPlex), and high-density solid-phase single nucleotide polymorphism genotyping. RESULTS Four hundred forty instances of 189 different disease-causing sequence variations were observed in this study, 98 of which have not been previously reported. One hundred forty-six of the 189 variations (77%) were observed in only a single individual. The observed variations were not evenly distributed among the LCA patients or among the eight genes. Empirical analysis of this uneven distribution was used to devise a multi-platform mutation detection strategy that is four times more efficient than a more conventional strategy of completely sequencing all of the coding regions of all LCA genes in all subjects. Hardy-Weinberg analysis of the observed mutations suggests that these eight genes are collectively responsible for about 70% of the cases of LCA in North America. The carrier frequency of the most common LCA allele (an intron 26 variation in CEP290) was found to be 2/3,248, which suggests that the overall prevalence of LCA in this population is about 1/81,000. An allele-specific ligation assay (SNPlex) was designed to detect 68 of the most common LCA-causing alleles, and semi-quantitative analysis of the data from this assay also revealed examples of gene deletion and isodisomy in the cohort. CONCLUSIONS The data demonstrates that a tiered screening strategy combining allele-specific detection with automated DNA sequencing can increase the efficiency of autosomal recessive mutation detection four-fold when compared with DNA sequencing alone. However, the very high rate of unique mutations observed in this study (77%) suggests that DNA sequencing will remain an important part of the overall strategy if high sensitivity is to be achieved.
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193
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Yang Z, Tong Z, Chorich LJ, Pearson E, Yang X, Moore A, Hunt DM, Zhang K. Clinical characterization and genetic mapping of North Carolina macular dystrophy. Vision Res 2007; 48:470-7. [PMID: 17976682 DOI: 10.1016/j.visres.2007.09.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2007] [Revised: 08/09/2007] [Accepted: 09/10/2007] [Indexed: 10/22/2022]
Abstract
North Carolina macular dystrophy (NCMD) is an autosomal dominant macular disease, was mapped to 6q14-q16.2, the disease-causing gene has yet not been identified. It shares phenotypic similarity with age-related macular degeneration including drusen and choroidal neovascularization. We collected six families with NCMD including 75 members, and conducted clinical characterization and genetic mapping for these families. Forty-five patients were diagnosed as NCMD; all six NCMD families were mapped to MCDR1 locus using genetic linkage analysis. MCDR1 interval was refined to 3 cM (1.8mb) between D6S1716 to D6S1671 via fine mapping using microsatellite markers in these six families, all eleven annotated genes within the interval were analyzed by mutation screening in coding regions, no mutation was found, suggesting a potential novel gene or a new pathological mechanism causing NCMD. The refinement of MCDR1 locus will aid the disease-causing gene identification. Functional studies of NCMD genes should provide important insights into pathogenetic mechanisms of NCMD and age-related macular degeneration.
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Affiliation(s)
- Zhenglin Yang
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences Center, Salt Lake City, UT 84132, USA.
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194
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McLaughlin PJ, Bakall B, Choi J, Liu Z, Sasaki T, Davis EC, Marmorstein AD, Marmorstein LY. Lack of fibulin-3 causes early aging and herniation, but not macular degeneration in mice. Hum Mol Genet 2007; 16:3059-70. [PMID: 17872905 DOI: 10.1093/hmg/ddm264] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
A mutation in the EFEMP1 gene causes Malattia Leventinese, an inherited macular degenerative disease with strong similarities to age-related macular degeneration. EFEMP1 encodes fibulin-3, an extracellular matrix protein of unknown function. To investigate its biological role, the murine Efemp1 gene was inactivated through targeted disruption. Efemp1(-/-) mice exhibited reduced reproductivity, and displayed an early onset of aging-associated phenotypes including reduced lifespan, decreased body mass, lordokyphosis, reduced hair growth, and generalized fat, muscle and organ atrophy. However, these mice appeared to have normal wound healing ability. Efemp1(-/-) mice on a C57BL/6 genetic background developed multiple large hernias including inguinal hernias, pelvic prolapse and protrusions of the xiphoid process. In contrast, Efemp1(-/-) mice on a BALB/c background rarely had any forms of hernias, indicating the presence of modifiers for fibulin-3's function in different mouse strains. Histological analysis revealed a marked reduction of elastic fibers in fascia, a thin layer of connective tissue maintaining and protecting structures throughout the body. No apparent macular degeneration associated defects were found in Efemp1(-/-) mice, suggesting that loss of fibulin-3 function is not the mechanism by which the mutation in EFEMP1 causes macular degeneration. These data demonstrate that fibulin-3 plays an important role in maintaining the integrity of fascia connective tissues and regulates aging.
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Affiliation(s)
- Precious J McLaughlin
- Department of Ophthalmology and Vision Science, University of Arizona, Tucson, AZ, USA
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195
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Radeke MJ, Peterson KE, Johnson LV, Anderson DH. Disease susceptibility of the human macula: Differential gene transcription in the retinal pigmented epithelium/choroid. Exp Eye Res 2007; 85:366-80. [PMID: 17662275 DOI: 10.1016/j.exer.2007.05.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 05/18/2007] [Accepted: 05/22/2007] [Indexed: 10/23/2022]
Abstract
The discoveries of gene variants associated with macular diseases have provided valuable insight into their molecular mechanisms, but they have not clarified why the macula is particularly vulnerable to degenerative disease. Its predisposition may be attributable to specialized structural features and/or functional properties of the underlying macular RPE/choroid. To examine the molecular basis for the macula's disease susceptibility, we compared the gene expression profile of the human RPE/choroid in the macula with the profile in the extramacular region using DNA microarrays. Seventy-five candidate genes with differences in macular:extramacular expression levels were identified by microarray analysis, of which 29 were selected for further analysis. Quantitative PCR confirmed that 21 showed statistically significant differences in expression. Five genes were expressed at higher levels in the macula. Two showed significant changes in the macular:extramacular expression ratio; another two exhibited changes in absolute expression level, as a function of age or AMD. Several of the differentially expressed genes have potential relevance to AMD pathobiology. One is an RPE cell growth factor (TFPI2), five are extracellular matrix components (DCN, MYOC, OGN, SMOC2, TFPI2), and six are related to inflammation (CCL19, CCL26, CXCL14, SLIT2) and/or angiogenesis (CXCL14, SLIT2, TFPI2, WFDC1). The identification of regional differences in gene expression in the RPE/choroid is a first step in clarifying the macula's propensity for degeneration. These findings lay the groundwork for further studies into the roles of the corresponding gene products in the normal, aged, and diseased macula.
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Affiliation(s)
- Monte J Radeke
- Center for the Study of Macular Degeneration, Neuroscience Research Institute, University of California, Santa Barbara, CA 93106, USA.
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196
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Ducros E, Berthaut A, Mirshahi P, Lemarchand S, Soria J, Legeais JM, Mirshahi M. Expression of extracellular matrix proteins fibulin-1 and fibulin-2 by human corneal fibroblasts. Curr Eye Res 2007; 32:481-90. [PMID: 17612964 DOI: 10.1080/02713680701411269] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE The fibulins are a family of extracellular matrix (ECM) molecules that regulate the organ shape along with other growth factors and stromal cells. We report here the in vitro expression of ECM proteins fibulin-1 and fibulin-2 by human corneal fibroblasts. The ability of fibulin-1 to modulate cell motility was investigated. METHODS Fibulin-1 and fibulin-2 mRNA and proteins expression were analyzed in primary and immortalized human corneal fibroblasts (CHN) respectively by gene array, RT-PCR, and immunocytochemistry. The motility and adhesion of the cells transfected with fibulin-1 siRNA were analyzed on tissue culture polystyrene coated with Matrigel or ECM secreted by those fibroblasts. RESULTS (1) The microarray analysis shows the expression of fibulin-1, fibulin-2, and their binding partners (i.e., fibronectin, nidogen-1, aggrecan, fibrilin-1, endostatin, and laminin alpha-2 chain). Interestingly, a matrix metalloprotease, ADAMTS-1, for which fibulin-1 acts as a cofactor, was also detected in CHN. (2) The synthesis by CHN of fibulin-1 and 2 mRNA and proteins was confirmed respectively by RT-PCR and immunocytochemistry. (3) Transfection of CHN by fibulin-1 siRNA has no effect on cell adhesion but increases cell migration compared with that of the control cells. This observation suggests an important role of fibulin-1 on cell motility. CONCLUSIONS The expression of fibulins and that of their binding partners by human corneal fibroblasts indicate the important role of these proteins in the organization of supramolecular ECM structures of cornea. The variation of their expression and the structural changes of fibulins remain to be determined in corneal pathology.
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Affiliation(s)
- E Ducros
- UMRS 736 INSERM - Université Pierre et Marie Curie (Paris 6), Faculté de Médecine Paris VI, Paris, France
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197
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Fu L, Garland D, Yang Z, Shukla D, Rajendran A, Pearson E, Stone EM, Zhang K, Pierce EA. The R345W mutation in EFEMP1 is pathogenic and causes AMD-like deposits in mice. Hum Mol Genet 2007; 16:2411-22. [PMID: 17666404 DOI: 10.1093/hmg/ddm198] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most common cause of vision loss in developed countries. A defining characteristic of this disorder is the accumulation of material between Bruch's membrane and the retinal pigment epithelium (RPE), first as microscopic basal deposits and later as clinically evident drusen. The pathogenesis of these deposits remains to be defined. Biochemical and genetic studies have suggested that inflammation and complement activation may play roles in AMD. Several lines of evidence also suggest that alterations to the extracellular matrix (ECM) of the RPE and choroid contribute to the development of AMD. The inherited macular degeneration Doyne honeycomb retinal dystrophy/Malattia Leventinese is thought to be caused by an R345W mutation in the EFEMP1 gene (also called fibulin-3). The pathogenicity of this mutation has been questioned because all individuals identified to date with the R345W mutation have shared a common haplotype. We investigated the pathogenicity of this mutation in families with early-onset macular degeneration and by generating Efemp1-R345W knockin mice. Genetic studies show that one of the identified families with the R345W mutation has a novel haplotype. The mutant Efemp1-R345W mice develop deposits of material between Bruch's membrane and the RPE, which resemble basal deposits in patients with AMD. These basal deposits contain Efemp1 and Timp3, an Efemp1 interacting protein. Evidence of complement activation was detected in the RPE and Bruch's membrane of the mutant mice. These results confirm that the R345W mutation in EFEMP1 is pathogenic. Further, they suggest that alterations in the ECM may stimulate complement activation, demonstrating a potential connection between these two etiologic factors in macular degeneration.
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Affiliation(s)
- Li Fu
- F.M. Kirby Center for Molecular Ophthalmology, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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198
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Lotery A, Trump D. Progress in defining the molecular biology of age related macular degeneration. Hum Genet 2007; 122:219-36. [PMID: 17659362 DOI: 10.1007/s00439-007-0406-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Accepted: 07/11/2007] [Indexed: 01/15/2023]
Abstract
Age related macular degeneration (AMD) is an extremely prevalent complex genetic disorder. Its incidence rises exponentially in the elderly to a frequency of 1 in 2 in the general population by age 85. It affects approximately 25 million people and is the commonest cause of irreversible visual loss in the Western world. It is therefore a major public health problem. However, until recently its aetiology was unknown. Our understanding of both the molecular biology of AMD and the relevant clinical treatments has progressed dramatically in the last 2 years. Two genes of large effect have been identified which together contribute to over 70% of the population attributable risk of AMD. Treatments which inhibit expression of vascular endothelial growth factor have been developed which can rescue vision in the "wet" form of the disease. The association of complement factor H with AMD highlights the importance of the alternative complement pathway in the development of AMD whilst the pathophysiology of the serine protease HTRA1 is now under intensive study. This review will give an insight into these developments and will summarise our current knowledge of the molecular biology of AMD.
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Affiliation(s)
- Andrew Lotery
- Clinical Neurosciences Division, University of Southampton, Southampton General Hospital, Southampton, SO16 6YD, UK.
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199
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Patel N, Adewoyin T, Chong NV. Age-related macular degeneration: a perspective on genetic studies. Eye (Lond) 2007; 22:768-76. [PMID: 17491602 DOI: 10.1038/sj.eye.6702844] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
AIM Age-related macular degeneration (AMD) is a common macular disease in the developed world and recent studies have shown that specific genes may be associated with it and may contribute to a higher risk of developing AMD. OBJECTIVE Our objective was to review systematically recent publications related to the genetics of AMD and provide relevant information that would help both scientists and clinicians in advising patients. METHOD A systematic search was performed on PubMed, Medline, and National Library of Medicine as well as ARVO abstracts using key words relevant to the genetic associations of AMD. RESULTS The most important genetic associations in AMD involved the complement factor H (CFH) gene, which showed that possession of the variant Y402H polymorphism significantly increases the risk for AMD. Protective genes have also been identified such as those on either factor B (BFor complement factor B (CFB)) or complement component 2 (C2) genes. The genes involved in inherited macular dystrophies such as ATP-binding cassette, subfamily A (ABC1), member 4 (ABCA4), vitelliform macular dystrophy (VMD2), tissue inhibitor of matrix metalloproteinase-3 (TIMP3), and EFEMP1have yielded some important information but further confirmatory work has yet to establish a clear association with AMD. CONCLUSION Patients with AMD possess specific genetic variants of the CFHgene, which put them at a higher risk of developing the disease. Other unaffected individuals may possess certain protective genetic variants, which could prevent them from developing AMD. Further research will no doubt shed light on other such mechanisms and these will be useful in identifying possible direct targets for drugs or indirectly through modulation of the genes responsible for disease presentation.
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Affiliation(s)
- N Patel
- Laser and Retinal Research Unit, Kings College Hospital, London, UK
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