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Chen X, Shi C, He M, Xiong S, Xia X. Endoplasmic reticulum stress: molecular mechanism and therapeutic targets. Signal Transduct Target Ther 2023; 8:352. [PMID: 37709773 PMCID: PMC10502142 DOI: 10.1038/s41392-023-01570-w] [Citation(s) in RCA: 64] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 06/17/2023] [Accepted: 07/14/2023] [Indexed: 09/16/2023] Open
Abstract
The endoplasmic reticulum (ER) functions as a quality-control organelle for protein homeostasis, or "proteostasis". The protein quality control systems involve ER-associated degradation, protein chaperons, and autophagy. ER stress is activated when proteostasis is broken with an accumulation of misfolded and unfolded proteins in the ER. ER stress activates an adaptive unfolded protein response to restore proteostasis by initiating protein kinase R-like ER kinase, activating transcription factor 6, and inositol requiring enzyme 1. ER stress is multifaceted, and acts on aspects at the epigenetic level, including transcription and protein processing. Accumulated data indicates its key role in protein homeostasis and other diverse functions involved in various ocular diseases, such as glaucoma, diabetic retinopathy, age-related macular degeneration, retinitis pigmentosa, achromatopsia, cataracts, ocular tumors, ocular surface diseases, and myopia. This review summarizes the molecular mechanisms underlying the aforementioned ocular diseases from an ER stress perspective. Drugs (chemicals, neurotrophic factors, and nanoparticles), gene therapy, and stem cell therapy are used to treat ocular diseases by alleviating ER stress. We delineate the advancement of therapy targeting ER stress to provide new treatment strategies for ocular diseases.
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Affiliation(s)
- Xingyi Chen
- Eye Center of Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Central South University, 410008, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Chaoran Shi
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Meihui He
- Eye Center of Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China
- Hunan Key Laboratory of Ophthalmology, Central South University, 410008, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Siqi Xiong
- Eye Center of Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China.
- Hunan Key Laboratory of Ophthalmology, Central South University, 410008, Changsha, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.
| | - Xiaobo Xia
- Eye Center of Xiangya Hospital, Central South University, 410008, Changsha, Hunan, China.
- Hunan Key Laboratory of Ophthalmology, Central South University, 410008, Changsha, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.
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2
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Reduced OPA1, Mitochondrial Fragmentation and Increased Susceptibility to Apoptosis in Granular Corneal Dystrophy Type 2 Corneal Fibroblasts. Genes (Basel) 2023; 14:genes14030566. [PMID: 36980838 PMCID: PMC10048436 DOI: 10.3390/genes14030566] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/20/2023] [Accepted: 02/22/2023] [Indexed: 03/03/2023] Open
Abstract
The progressive degeneration of granular corneal dystrophy type 2 (GCD2) corneal fibroblasts is associated with altered mitochondrial function, but the underlying mechanisms are incompletely understood. We investigated whether an imbalance of mitochondrial dynamics contributes to mitochondrial dysfunction of GCD2 corneal fibroblasts. Transmission electron microscopy revealed several small, structurally abnormal mitochondria with altered cristae morphology in GCD2 corneal fibroblasts. Confocal microscopy showed enhanced mitochondrial fission and fragmented mitochondrial tubular networks. Western blotting revealed higher levels of MFN1, MFN2, and pDRP1 and decreased levels of OPA1 and FIS1 in GCD2. OPA1 reduction by short hairpin RNA (shRNA) resulted in fragmented mitochondrial tubular networks and increased susceptibility to mitochondrial stress-induced apoptosis. A decrease in the mitochondrial biogenesis-related transcription factors NRF1 and PGC1α was observed, while there was an increase in the mitochondrial membrane proteins TOM20 and TIM23. Additionally, reduced levels of mitochondrial DNA (mtDNA) were exhibited in GCD2 corneal fibroblasts. These observations suggest that altered mitochondrial fission/fusion and biogenesis are the critical molecular mechanisms that cause mitochondrial dysfunction contributing to the degeneration of GCD2 corneal fibroblasts.
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3
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Ji YW, Ahn H, Shin KJ, Kim TI, Seo KY, Stulting RD, Kim EK. De Novo L509P Mutation of the TGFBI Gene Associated with Slit-Lamp Findings of Lattice Corneal Dystrophy Type IIIA. J Clin Med 2022; 11:jcm11113055. [PMID: 35683443 PMCID: PMC9181583 DOI: 10.3390/jcm11113055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Mutations of the transforming growth factor-β-induced (TGFBI) gene produce various types of corneal dystrophy. Here, we report a novel de novo L509P mutation not located in a known hot spot of the transforming growth factor-β-induced (TGFBI) gene and its clinical phenotype, which resembles that of lattice corneal dystrophy type IIIA (LCD IIIA). Case presentation: A 36-year-old man (proband) visited our clinic due to decreased visual acuity with intermittent ocular irritation in conjunction with painful recurrent erosions in both eyes for 10 years. Molecular genetic analyses revealed a TGFBI L509P mutation (c.1526T>C) in the proband and one of his sons. Interestingly, neither TGFBI mutations nor corneal abnormalities were detected in either of the proband’s biological parents, indicating the occurrence of a de novo L509P mutation. Clinical examinations, including slit-lamp retro-illumination and Fourier-domain anterior segment optical coherence tomography (FD-OCT), revealed gray deposits in the anterior stroma and deeper refractile lines extending from limbus to limbus in both corneas of the proband, consistent with a diagnosis of LCD IIIA. Superficial diffuse haze and surface irregularity were observed in conjunction with corneal erosions and visual impairment, necessitating phototherapeutic keratectomy (PTK). A 60 μm PTK of the Bowman layer and anterior stroma of the proband’s left eye was performed following the removal of the epithelium in order to remove superficial corneal opacities. His BCVA improved from 20/400 to 20/50 at postoperative week 8 and was maintained for 45 months. Pinhole-corrected VA was 20/20 at the last visit, and corneal opacities had not recurred. Conclusions: An inheritable de novo mutation of L509P in the TGFBI gene can produce severe LCD IIIA, which can be successfully treated with OCT-guided PRK.
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Affiliation(s)
- Yong Woo Ji
- Department of Ophthalmology, Yongin Severance Hospital, Yonsei University College of Medicine, Yongin 16995, Korea;
| | - Hyunmin Ahn
- Department of Ophthalmology, Institute of Vision Research, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea; (H.A.); (T.-i.K.); (K.Y.S.)
| | - Kyoung-Jin Shin
- Department of Forensic Medicine, Yonsei University College of Medicine, Seoul 03722, Korea;
| | - Tae-im Kim
- Department of Ophthalmology, Institute of Vision Research, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea; (H.A.); (T.-i.K.); (K.Y.S.)
- Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Kyoung Yul Seo
- Department of Ophthalmology, Institute of Vision Research, Severance Hospital, Yonsei University College of Medicine, Seoul 03722, Korea; (H.A.); (T.-i.K.); (K.Y.S.)
| | | | - Eung Kweon Kim
- Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul 03722, Korea
- Saevit Eye Hospital, Goyang 10447, Korea
- Correspondence:
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de Barros MRM, Chakravarti S. Pathogenesis of keratoconus: NRF2-antioxidant, extracellular matrix and cellular dysfunctions. Exp Eye Res 2022; 219:109062. [PMID: 35385756 DOI: 10.1016/j.exer.2022.109062] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 03/19/2022] [Accepted: 03/30/2022] [Indexed: 11/04/2022]
Abstract
Keratoconus (KC) is a degenerative disease associated with cell and extracellular matrix (ECM) loss that causes gradual thinning and steepening of the cornea and loss of vision. Collagen cross linking with ultraviolet light treatment can strengthen the ECM and delay weakening of the cornea, but severe cases require corneal transplantation. KC is multifactorial and multigenic, but its pathophysiology is still an enigma. Multiple approaches are being pursued to elucidate the molecular changes that underlie the corneal phenotype to identify relevant genes for tailored candidate searches and to develop potential biomarkers and targets for therapeutic interventions. Recent proteomic and transcriptomic studies suggest dysregulations in oxidative stress, NRF2-regulated antioxidant programs, WNT-signaling, TGF-β, ECM and matrix metalloproteinases. This review aims to provide a broad update on the transcriptomic and proteomic studies of KC with a focus on findings that relate to oxidative stress, and dysregulations in cellular and extracellular matrix functions.
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Affiliation(s)
| | - Shukti Chakravarti
- Department of Ophthalmology, NYU Grossman School of Medicine, NY, 10016, USA; Department of Pathology, NYU Grossman School of Medicine, NY, 10016, USA.
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Kim SY, Lee SM, Shin J, Lee JE, Kim SJ. Two Cases of Ocular Manifestations in Patients with Microdeletion of the Chromosome 7 Long Arm. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2021. [DOI: 10.3341/jkos.2021.62.7.1003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Purpose: We report ocular manifestations in two patients with 7q microdeletion. Case summary: (Case 1) A 62-day-old male infant was admitted to the ophthalmology outpatient department for ocular examination after being diagnosed with microdeletion of chromosome seven (7q36.2q36.3 deletion) in DNA microarray comparative genomic hybridization (DNA microarray CGH) and fluorescence in situ hybridization (FISH) tests. Fundus examination showed optic disc hypoplasia in both eyes and retinopathy of prematurity, accompanied by retinal hemorrhage in his right eye. Around the age of 24 months, the patient was diagnosed with intermittent exotropia with anisometropia and was prescribed spectacles. (Case 2) A 3-year-old male infant was referred to the ophthalmology clinic to evaluate poor fixation, which was found during rehabilitation therapy for cerebral palsy and developmental delay. Fundus examination showed an increased cup/disc ratio bilaterally. A flash visual evoked potential test indicated a decrease in amplitude in his right eye. Intermittent exotropia of forty prism diopters was observed. DNA microarray CGH and FISH tests performed at another hospital revealed microdeletion of chromosome seven (7q35 microdeletion) and CNTNAP2 gene loss. Conclusions: When genetic anomalies associated with ocular development are identified, it is necessary to detect the ophthalmic abnormalities early and provide the appropriate treatment to allow for the development of normal visual function.
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Chu HS, Peterson C, Jun A, Foster J. Targeting the integrated stress response in ophthalmology. Curr Eye Res 2021; 46:1075-1088. [PMID: 33474991 DOI: 10.1080/02713683.2020.1867748] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Purpose: To summarize the Integrated Stress Response (ISR) in the context of ophthalmology, with special interest on the cornea and anterior segment. Results: The ISR is a powerful and conserved signaling pathway that allows for cells to respond to a diverse array of both intracellular and extracellular stressors. The pathway is classically responsible for coordination of the cellular response to amino acid starvation, ultraviolet light, heme dysregulation, viral infection, and unfolded protein. Under normal circumstances, it is considered pro-survival and a necessary mechanism through which protein translation is controlled. However, in cases of severe or prolonged stress the pathway can promote apoptosis, and loss of normal cellular phenotype. The activation of this pathway culminates in the global inhibition of cap-dependent protein translation and the canonical expression of the activating transcription factor 4 (ATF4). Conclusion:The eye is uniquely exposed to ISR responsive stressors due to its environmental exposure and relative isolation from the circulatory system which are necessary for its function. We will discuss how this pathway is critical for the proper function of the tissue, its role in development, as well as how targeting of the pathway could alleviate key aspects of diverse ophthalmic diseases.
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Affiliation(s)
- Hsiao-Sang Chu
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University, Baltimore, MD, USA.,Department of Ophthalmology, National Taiwan University Hospital, College of Medicine, National Taiwan University, Taipei City, Taiwan.,Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei City, Taiwan
| | - Cornelia Peterson
- Department of Molecular & Comparative Pathobiology, Johns Hopkins University, Baltimore, MD, USA
| | - Albert Jun
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University, Baltimore, MD, USA
| | - James Foster
- Wilmer Eye Institute, Department of Ophthalmology, Johns Hopkins University, Baltimore, MD, USA
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Choi SI, Woo JH, Kim EK. Lysosomal dysfunction of corneal fibroblasts underlies the pathogenesis of Granular Corneal Dystrophy Type 2 and can be rescued by TFEB. J Cell Mol Med 2020; 24:10343-10355. [PMID: 32667742 PMCID: PMC7521267 DOI: 10.1111/jcmm.15646] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 02/17/2020] [Accepted: 04/17/2020] [Indexed: 01/13/2023] Open
Abstract
Granular corneal dystrophy type 2 (GCD2) is the most common form of transforming growth factor β‐induced (TGFBI) gene‐linked corneal dystrophy and is pathologically characterized by the corneal deposition of mutant‐TGFBIp. The defective autophagic degradation of pathogenic mutant‐TGFBIp has been shown in GCD2; however, its exact mechanisms are unknown. To address this, we investigated lysosomal functions using corneal fibroblasts. Levels of cathepsins K and L (CTSK and CTSL) were significantly decreased in GCD2 cells, but of cathepsins B and D (CTSB and CTSD) did not change. The maturation of the pro‐enzymes to their active forms (CTSB, CTSK and CTSL) was inhibited in GCD2 cells. CTSL enzymes directly degraded both LC3 (autophagosomes marker) and mutant‐TGFBIp. Exogenous CTSL expression dramatically reduced mutant‐TGFBIp in GCD2 cells, but not TGFBIp in WT cells. An increased lysosomal pH and clustered lysosomal perinuclear position were found in GCD2 cells. Transcription factor EB (TFEB) levels were significantly reduced in GCD2 cells, compared to WT. Notably, exogenous TFEB expression improved mutant‐TGFBIp clearance and lysosomal abnormalities in GCD2 cells. Taken together, lysosomal dysfunction in the corneal fibroblasts underlies the pathogenesis of GCD2, and TFEB has a therapeutic potential in the treatment of GCD2.
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Affiliation(s)
- Seung-Il Choi
- Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Jong Hwan Woo
- Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Eung Kweon Kim
- Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea.,Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea.,Institute of Vision Research, Yonsei University College of Medicine, Seoul, South Korea
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Familial association of keratoconus and granular corneal dystrophy: The familial case series. North Clin Istanb 2019; 6:176-183. [PMID: 31297486 PMCID: PMC6593915 DOI: 10.14744/nci.2018.08860] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 04/23/2018] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE: The aim of the present study was to evaluate the coexistence of bilateral keratoconus and granular corneal dystrophy (GCD) in the members of a family. METHODS: A total of 22 patients were examined in four generations of the family tree in this family screening study. Visual acuity test, biomicroscopic examination, and fundus examination were performed in all patients. The diagnosis of granular dystrophy was based on biomicroscopic examination findings. Corneal topography was performed on the patients diagnosed with granular dystrophy and other family members aged >5 years with normal examination findings. Corneal photographs were obtained from all patients with granular dystrophy except one case. RESULTS: Keratoconus or subclinical keratoconus was detected in seven cases. In addition, GCD type 1 was found in six of the seven cases. All patients diagnosed with keratoconus and granular dystrophy were females. On the other hand, there was no ophthalmologic problem in the men of the family tree. Although an autosomal dominant inheritance was found, the onset of the disease only in women suggests that there may be a variant expression. CONCLUSION: The present study showed an association of GCD and keratoconus in four generations of a family. More research is required to further explain this association.
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Kim EK, Kim S, Maeng YS. Generation of TGFBI knockout ABCG2+/ABCB5+ double-positive limbal epithelial stem cells by CRISPR/Cas9-mediated genome editing. PLoS One 2019; 14:e0211864. [PMID: 30753226 PMCID: PMC6372159 DOI: 10.1371/journal.pone.0211864] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 01/23/2019] [Indexed: 12/26/2022] Open
Abstract
Corneal dystrophy is an autosomal dominant disorder caused by mutations of the transforming growth factor β-induced (TGFBI) gene on chromosome 5q31.8. This disease is therefore ideally suited for gene therapy using genome-editing technology. Here, we isolated human limbal epithelial stem cells (ABCG2+/ABCB5+ double-positive LESCs) and established a TGFBI knockout using RNA-guided clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 genome editing. An LESC clone generated with a single-guide RNA (sgRNA) targeting exon 4 of the TGFBI gene was sequenced in order to identify potential genomic insertions and deletions near the Cas9/sgRNA-target sites. A detailed analysis of the differences between wild type LESCs and the single LESC clone modified by the TGFBI-targeting sgRNA revealed two distinct mutations, an 8 bp deletion and a 14 bp deletion flanked by a single point mutation. These mutations each lead to a frameshift missense mutation and generate premature stop codons downstream in exon 4. To validate the TGFBI knockout LESC clone, we used single cell culture to isolate four individual sub-clones, each of which was found to possess both mutations present in the parent clone, indicating that the population is homogenous. Furthermore, we confirmed that TGFBI protein expression is abolished in the TGFBI knockout LESC clone using western blot analysis. Collectively, our results suggest that genome editing of TGFBI in LESCs by CRISPR/Cas9 may be useful strategy to treat corneal dystrophy.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily G, Member 2/genetics
- CRISPR-Cas Systems/genetics
- Corneal Dystrophies, Hereditary/genetics
- Corneal Dystrophies, Hereditary/pathology
- Corneal Dystrophies, Hereditary/therapy
- Epithelial Cells/metabolism
- Epithelial Cells/pathology
- Extracellular Matrix Proteins/genetics
- Extremities/growth & development
- Extremities/pathology
- Gene Editing
- Gene Expression Regulation/genetics
- Gene Knockout Techniques
- Genetic Therapy
- Humans
- Primary Cell Culture
- RNA, Guide, CRISPR-Cas Systems/genetics
- Sequence Deletion/genetics
- Single-Cell Analysis
- Stem Cells/metabolism
- Transforming Growth Factor beta/genetics
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Affiliation(s)
- Eung Kweon Kim
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
- Institute of Vision Research, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Seunghyuk Kim
- Institute of Vision Research, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Yong-Sun Maeng
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
- Department of Obstetrics and Gynecology, Institute of Women’s Life Medical Science, Yonsei University College of Medicine, Seoul, Republic of Korea
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Nejat F, Aghamollaei H, Pirhadi S, Jadidi K, Nejat MA. Simultaneous Presence of Macular Corneal Dystrophy and Retinitis Pigmentosa in Three Members of a Family. IRANIAN JOURNAL OF MEDICAL SCIENCES 2018; 43:227-230. [PMID: 29749994 PMCID: PMC5936857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Macular corneal dystrophy (MCD) is an autosomal recessive hereditary disease. In most cases, various mutations in carbohydrate sulfotransferase 6 (CHST6) gene are the main cause of MCD. These mutations lead to a defect in keratan sulfate synthesis. Retinitis pigmentosa (RP) is another eye disorder with nyctalopia as its common symptom. It has been shown that more than 65 genes have been implicated in different forms of RP. Herein, we report on a 9-member family with 2 girls and 5 boys. Both parents, one of the girls and one of the boys had normal eye vision and another boy had keratoconus. Other children (1 girl and 2 boys) suffered from both MCD and RP. Corneal transplantation and medical supplements were used for MCD and RP during the follow-up period, respectively. Based on the family tree, it seems that the inheritance of both diseases is autosomal recessive. Based on our search of databases, there is no report on the simultaneous presence of MCD and RP. To the best of our knowledge, the present article is the first case report on this topic. Molecular genetic investigation is needed to clarify the mechanism of concurrent MCD and RP.
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Affiliation(s)
| | - Hossein Aghamollaei
- Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Shiva Pirhadi
- Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - Khosrow Jadidi
- Department of Ophthalmology, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammad Amin Nejat
- Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
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Qu C, Yu M, Guo X, Li J, Liu X, Shi Y, Gong B. Transforming growth factor β induced mutation-associated phenotype in a Chinese family exhibiting lattice corneal dystrophy. Biomed Rep 2017; 7:314-318. [PMID: 29085627 DOI: 10.3892/br.2017.975] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 08/18/2017] [Indexed: 01/15/2023] Open
Abstract
Lattice corneal dystrophy type I (LCDI) is associated with a large number of missense mutations in the transforming growth factor β induced (TGFBI) gene. The aim of the present study was to analyze TGFBI mutation in a Chinese family with LCDI, and to describe the clinical features and phenotype-genotype correlation within this family. Three generations of this family with LCDI were enrolled in the current study. Complete ophthalmic examinations were performed on all family members and mutation screenings of the coding regions of TGFBI were analyzed using a direct sequencing method. All family members underwent slit-lamp examination, and two patients and one of normal members in the family were evaluated by laser scanning in vivo confocal microscopy. A single heterozygous c.370C>T (p.R124C) mutation was identified in exon 4 of the TGFBI gene in five affected individuals, but not in the other family members and 400 normal control subjects. The affected members exhibited similar clinical features of LCDI, except that patient III:5 presented with mild symptoms. Confocal microscopy in vivo examination demonstrated that the proband (II:2) and his affected niece (III:4) had disruptions in multiple corneal layers, including the basal epithelial cells, stroma cells and Bowman's membrane. Thus, the R124C mutation in the TGFBI gene was identified in a Chinese family with LCDI. These results characterized the clinical features and revealed a genotype-associated phenotype in this family, which may contribute to understanding the pathogenesis of LCDI.
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Affiliation(s)
- Chao Qu
- Sichuan Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, P.R. China.,Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, P.R. China
| | - Man Yu
- Sichuan Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, P.R. China.,Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, P.R. China
| | - Xiaoxin Guo
- Sichuan Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, P.R. China
| | - Jing Li
- Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, P.R. China
| | - Xiaoqi Liu
- Sichuan Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, P.R. China
| | - Yi Shi
- Sichuan Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, P.R. China
| | - Bo Gong
- Sichuan Key Laboratory for Disease Gene Study, Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan 610072, P.R. China
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On the Origin of Superoxide Dismutase: An Evolutionary Perspective of Superoxide-Mediated Redox Signaling. Antioxidants (Basel) 2017; 6:antiox6040082. [PMID: 29084153 PMCID: PMC5745492 DOI: 10.3390/antiox6040082] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 10/23/2017] [Accepted: 10/27/2017] [Indexed: 12/15/2022] Open
Abstract
The field of free radical biology originated with the discovery of superoxide dismutase (SOD) in 1969. Over the last 5 decades, a plethora of research has been performed in species ranging from bacteria to mammals that has elucidated the molecular reaction, subcellular location, and specific isoforms of SOD. However, while humans have only begun to study this class of enzymes over the past 50 years, it has been estimated that these enzymes have existed for billions of years, and may be some of the original enzymes found in primitive life. As life evolved over this expanse of time, these enzymes have taken on new and different functional roles potentially in contrast to how they were originally derived. Herein, examination of the evolutionary history of these enzymes provides both an explanation and further inquiries into the modern-day role of SOD in physiology and disease.
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Choi SI, Lee E, Akuzum B, Jeong JB, Maeng YS, Kim TI, Kim EK. Melatonin reduces endoplasmic reticulum stress and corneal dystrophy-associated TGFBIp through activation of endoplasmic reticulum-associated protein degradation. J Pineal Res 2017; 63. [PMID: 28580641 DOI: 10.1111/jpi.12426] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 05/31/2017] [Indexed: 02/06/2023]
Abstract
Endoplasmic reticulum (ER) stress is emerging as a factor for the pathogenesis of granular corneal dystrophy type 2 (GCD2). This study was designed to investigate the molecular mechanisms underlying the protective effects of melatonin on ER stress in GCD2. Our results showed that GCD2 corneal fibroblasts were more susceptible to ER stress-induced death than were wild-type cells. Melatonin significantly inhibited GCD2 corneal cell death, caspase-3 activation, and poly (ADP-ribose) polymerase 1 cleavage caused by the ER stress inducer, tunicamycin. Under ER stress, melatonin significantly suppressed the induction of immunoglobulin heavy-chain-binding protein (BiP) and activation of inositol-requiring enzyme 1α (IRE1α), and their downstream target, alternative splicing of X-box binding protein 1(XBP1). Notably, the reduction in BiP and IRE1α by melatonin was suppressed by the ubiquitin-proteasome inhibitor, MG132, but not by the autophagy inhibitor, bafilomycin A1, indicating involvement of the ER-associated protein degradation (ERAD) system. Melatonin treatment reduced the levels of transforming growth factor-β-induced protein (TGFBIp) significantly, and this reduction was suppressed by MG132. We also found reduced mRNA expression of the ERAD system components HRD1 and SEL1L, and a reduced level of SEL1L protein in GCD2 cells. Interestingly, melatonin treatments enhanced SEL1L levels and suppressed the inhibition of SEL1L N-glycosylation caused by tunicamycin. In conclusion, this study provides new insights into the mechanisms by which melatonin confers its protective actions during ER stress. The results also indicate that melatonin might have potential as a therapeutic agent for ER stress-related diseases including GCD2.
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Affiliation(s)
- Seung-Il Choi
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Eunhee Lee
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Begum Akuzum
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Jang Bin Jeong
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Yong-Sun Maeng
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Tae-Im Kim
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Korea
- Institute of Vision Research, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
| | - Eung Kweon Kim
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Korea
- Institute of Vision Research, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Korea
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Choi SI, Lee E, Jeong JB, Akuzum B, Maeng YS, Kim TI, Kim EK. 4-Phenylbutyric acid reduces mutant-TGFBIp levels and ER stress through activation of ERAD pathway in corneal fibroblasts of granular corneal dystrophy type 2. Biochem Biophys Res Commun 2016; 477:841-846. [PMID: 27373828 DOI: 10.1016/j.bbrc.2016.06.146] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Accepted: 06/28/2016] [Indexed: 11/28/2022]
Abstract
Granular corneal dystrophy type 2 (GCD2) is caused by a point mutation (R124H) in the transforming growth factor β-induced (TGFBI) gene. In GCD2 corneal fibroblasts, secretion of the accumulated mutant TGFBI-encoded protein (TGFBIp) is delayed via the endoplasmic reticulum (ER)/Golgi-dependent secretory pathway. However, ER stress as the pathogenic mechanism underlying GCD2 has not been fully characterized. The aim of this study was to confirm whether ER stress is linked to GCD2 pathogenesis and whether the chemical chaperone, 4-phenylbutyric acid (4-PBA), could be exploited as a therapy for GCD2. We found that the ER chaperone binding immunoglobulin protein (BiP) and the protein disulfide isomerase (PDI) were elevated in GCD2. Western bolt analysis also showed a significant increase in both the protein levels and the phosphorylation of the key ER stress kinases, inositol-requiring enzyme 1α (IRE1α) and double stranded RNA activated protein kinase (PKR)-like ER kinase, as well as in levels of their downstream targets, X box-binding protein 1 (XBP1) and activating transcription factor 4, respectively, in GCD2 corneal fibroblasts. GCD2 cells were found to be more susceptible to ER stress-induced cell death than were wild-type corneal fibroblasts. Treatment with 4-PBA considerably reduced the levels of BiP, IRE1α, and XBP1 in GCD2 cells; notably, 4-PBA treatment significantly reduced the levels of TGFBIp without change in TGFBI mRNA levels. In addition, TGFBIp levels were significantly reduced under ER stress and this reduction was considerably suppressed by the ubiquitin proteasome inhibitor MG132, indicating TGFBIp degradation via the ER-associated degradation pathway. Treatment with 4-PBA not only protected against the GCD2 cell death induced by ER stress but also significantly suppressed the MG132-mediated increase in TGFBIp levels under ER stress. Together, these results suggest that ER stress might comprise an important factor in GCD2 pathophysiology and that the effects of 4-PBA treatment might have important implications for the development of GCD2 therapeutics.
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Affiliation(s)
- Seung-Il Choi
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Eunhee Lee
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Jang Bin Jeong
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Begum Akuzum
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Yong-Sun Maeng
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Tae-Im Kim
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea; Institute of Vision Research, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Eung Kweon Kim
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea; Institute of Vision Research, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, South Korea.
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Choi SI, Kim EK. Autophagy in granular corneal dystrophy type 2. Exp Eye Res 2016; 144:14-21. [DOI: 10.1016/j.exer.2015.09.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 08/28/2015] [Accepted: 09/15/2015] [Indexed: 01/07/2023]
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TGF-β regulates TGFBIp expression in corneal fibroblasts via miR-21, miR-181a, and Smad signaling. Biochem Biophys Res Commun 2016; 472:150-5. [DOI: 10.1016/j.bbrc.2016.02.086] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Accepted: 02/21/2016] [Indexed: 12/12/2022]
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Pathogenesis and treatments of TGFBI corneal dystrophies. Prog Retin Eye Res 2015; 50:67-88. [PMID: 26612778 DOI: 10.1016/j.preteyeres.2015.11.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/12/2015] [Accepted: 11/16/2015] [Indexed: 11/22/2022]
Abstract
Transforming growth factor beta-induced (TGFBI) corneal dystrophies are a group of inherited progressive corneal diseases. Accumulation of transforming growth factor beta-induced protein (TGFBIp) is involved in the pathogenesis of TGFBI corneal dystrophies; however, the exact molecular mechanisms are not fully elucidated. In this review article, we summarize the current knowledge of TGFBI corneal dystrophies including clinical manifestations, epidemiology, most common and recently reported associated mutations for each disease, and treatment modalities. We review our current understanding of the molecular mechanisms of granular corneal dystrophy type 2 (GCD2) and studies of other TGFBI corneal dystrophies. In GCD2 corneal fibroblasts, alterations of morphological characteristics of corneal fibroblasts, increased susceptibility to intracellular oxidative stress, dysfunctional and fragmented mitochondria, defective autophagy, and alterations of cell cycle were observed. Other studies of mutated TGFBIp show changes in conformational structure, stability and proteolytic properties in lattice and granular corneal dystrophies. Future research should be directed toward elucidation of the biochemical mechanism of deposit formation, the relationship between the mutated TGFBIp and the other materials in the extracellular matrix, and the development of gene therapy and pharmaceutical agents.
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Maeng YS, Lee GH, Choi SI, Kim KS, Kim EK. Histone methylation levels correlate with TGFBIp and extracellular matrix gene expression in normal and granular corneal dystrophy type 2 corneal fibroblasts. BMC Med Genomics 2015; 8:74. [PMID: 26553048 PMCID: PMC4638082 DOI: 10.1186/s12920-015-0151-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 11/04/2015] [Indexed: 01/01/2023] Open
Abstract
Background TGFβ1-induced expression of transforming growth factor β-induced protein (TGFBIp) and extracellular matrix (ECM) genes plays a major role in the development of granular corneal dystrophy type 2 (GCD2: also called Avellino corneal dystrophy). Although some key transcription factors are known, the epigenetic mechanisms modulating TGFBIp and ECM expression remain unclear. We examined the role of chromatin markers such as histone H3 lysine methylation (H3Kme) in TGFβ1-induced TGFBIp and ECM gene expression in normal and GCD2-derived human corneal fibroblasts. Methods Wild-type (n = 3), GCD2-heterozygous (n = 1), and GCD2-homozygous (n = 3) primary human corneal fibroblasts were harvested from human donors and patients prepared. Microarray and gene-expression profiling, Chromatin immunoprecipitation microarray analysis, and Methylated DNA isolation assay-assisted CpG microarrays was performed in Wild-type and GCD2-homozygous human cells. Results Transcription and extracellular-secretion levels of TGFBIp were high in normal cells compared with those in GCD2-derived cells and were related to H3K4me3 levels but not to DNA methylation over the TGFBI locus. TGFβ1 increased the expression of TGFBIp and the ECM-associated genes connective tissue growth factor, collagen-α2[Ι], and plasminogen activator inhibitor-1 in normal corneal fibroblasts. Increased levels of gene-activating markers (H3K4me1/3) and decreased levels of repressive markers (H3K27me3) at the promoters of those gene accompanied the changes in expression. TGFβ1 also increased recruitment of the H3K4 methyltransferase MLL1 and of SET7/9 and also the binding of Smad3 to the promoters. Knockdown of both MLL1 and SET7/9 significantly blocked the TGFβ1-induced gene expression and inhibited TGFβ1-induced changes in promoter H3K4me1/3 levels. Those effects were very weak, however, in GCD2-derived corneal fibroblasts. Conclusions Taken together, the results show the functional role of H3K4me in TGFβ1-mediated TGFBIp and ECM gene expression in corneal fibroblasts. Pharmacologic and other therapies that regulate these modifications could have potential cornea-protective effects for granular corneal dystrophy. Electronic supplementary material The online version of this article (doi:10.1186/s12920-015-0151-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Yong-Sun Maeng
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul, 120-752, South Korea
| | - Ga-Hyun Lee
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul, 120-752, South Korea
| | - Seung-Il Choi
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul, 120-752, South Korea
| | - Kyu Seo Kim
- Emory University School of Medicine, Atlanta, GA, USA
| | - Eung Kweon Kim
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, 250 Seongsanno, Seodaemun-gu, Seoul, 120-752, South Korea. .,Institute of Vision Research, Severance Biomedical Science Institute, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea.
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Saleh S, Brownstein S, Manusow JS, Jastrzebski A, Lam K, Sassani JW, Mintsioulis G, Gilberg SM. Secondary corneal amyloidosis after perforating corneal trauma: A series of 5 cases and review of the literature. Surv Ophthalmol 2015; 60:590-5. [PMID: 26253297 DOI: 10.1016/j.survophthal.2015.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Revised: 06/25/2015] [Accepted: 07/17/2015] [Indexed: 10/23/2022]
Abstract
We retrospectively reviewed the clinical and surgical histories of 5 patients with traumatic secondary corneal amyloidosis, a relatively rare sequela of nonsurgical and surgical perforating corneal trauma. Four had history of nonsurgical trauma, and 1 had surgical trauma to the cornea. Three specimens were obtained by penetrating keratoplasties and 2 by excision of the cornea during evisceration of the ocular contents. All the corneal specimens showed full-thickness scars of a prior perforating wound with congophilic amyloid deposits that exhibited apple-green birefringence under polarized light and dichroism. All cases had variable degrees of predominantly chronic nongranulomatous inflammation. Ultrastructural examination in 1 patient disclosed 8-nm diameter fibrils in disarray, consistent with amyloid. Amyloid P immunostaining was positive in all 3 patients tested for this protein.
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Affiliation(s)
- Solin Saleh
- Department of Ophthalmology, The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Pathology, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Seymour Brownstein
- Department of Ophthalmology, The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Pathology, The Ottawa Hospital, Ottawa, Ontario, Canada.
| | - Joshua S Manusow
- Department of Ophthalmology, The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Pathology, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - André Jastrzebski
- Department of Ophthalmology, The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Pathology, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Kay Lam
- Department of Ophthalmology, The Ottawa Hospital, Ottawa, Ontario, Canada; Department of Pathology, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Joseph W Sassani
- Department of Ophthalmology, Milton S. Hershey Medical Centre, Pennsylvania State University, Hershey, Pennsylvania, USA; Department of Pathology, Milton S. Hershey Medical Centre, Pennsylvania State University, Hershey, Pennsylvania, USA
| | - George Mintsioulis
- Department of Ophthalmology, The Ottawa Hospital, Ottawa, Ontario, Canada
| | - Steven M Gilberg
- Department of Ophthalmology, The Ottawa Hospital, Ottawa, Ontario, Canada
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Kim EK, Lee H, Choi SI. Molecular Pathogenesis of Corneal Dystrophies: Schnyder Dystrophy and Granular Corneal Dystrophy type 2. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:99-115. [PMID: 26310152 DOI: 10.1016/bs.pmbts.2015.05.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The International Committee for Classification of Corneal Dystrophies (IC3D) provides updated data to ophthalmologists by incorporating traditional definitions of corneal dystrophies with new genetic, clinical, and pathologic information. Recent advances in the genetics of corneal dystrophies facilitate more precise classifications and elucidate each classification's molecular mechanisms. Unfortunately, the molecular mechanisms and underlying pathogenic mechanisms have remained obscure, with the exception of Schnyder corneal dystrophy (CD), granular CD type 2 (GCD2), and Fuch's endothelial CD. Here, we review the pathogenesis of Schnyder CD and GCD2.
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Affiliation(s)
- Eung Kweon Kim
- Department of Ophthalmology, Vision Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea; Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea; BK21 Plus Project for Medical Science and Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, Republic of Korea.
| | - Hun Lee
- Department of Ophthalmology, Vision Research Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea; Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Seung-Il Choi
- Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea
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Inhibitory Effect of Tranilast on Transforming Growth Factor-Beta-Induced Protein in Granular Corneal Dystrophy Type 2 Corneal Fibroblasts. Cornea 2015; 34:950-8. [PMID: 26020822 DOI: 10.1097/ico.0000000000000466] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE To investigate the effects of tranilast, an inhibitor of chemical mediators and fibroblast proliferation, on the expression of transforming growth factor-beta (TGF-β)-induced protein (TGFBIp) in wild-type (WT) and homozygous (HO) granular corneal dystrophy type 2 corneal fibroblasts. METHODS Cell proliferation and cytotoxicity were measured by Cell Counting Kit-8 and lactate dehydrogenase assay. Western blotting and real-time polymerase chain reaction were used to determine changes in the expression of TGFBIp and TGFBI mRNA. We determined the effects of tranilast on phosphorylated Smad2 (pSmad2) and pSmad3, wound-healing, and expression of alpha-smooth muscle actin (α-SMA), type I collagen, and integrins. RESULTS High concentrations of tranilast decreased proliferation of corneal fibroblasts but did not cause elevation of lactate dehydrogenase, except at 1.0 mM tranilast. TGF-β increased the expression of TGFBIp and TGFBI mRNA in WT and HO corneal fibroblasts. Cotreatment of corneal fibroblasts with tranilast and TGF-β reduced the levels of TGFBIp and TGFBI mRNA. In addition, application of tranilast reduced pSmad2 in WT and HO corneal fibroblasts and pSmad3 in HO corneal fibroblasts, both of which were increased initially by TGF-β. Tranilast delayed wound healing and reduced the expression of α-SMA, type I collagen, and some of integrins in WT and HO corneal fibroblasts. CONCLUSIONS Application of tranilast in WT and HO corneal fibroblasts inhibited the expression of TGFBIp by blocking TGF-β signaling. Thus, tranilast may be useful in delaying or preventing the recurrence of corneal opacity in TGFBI-linked corneal dystrophies if clinical studies confirm these findings.
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Jung JW, Kim SA, Kang EM, Kim TI, Cho HS, Kim EK. Lattice corneal dystrophy type IIIA with hyaline component from a novel A620P mutation and distinct surgical treatments. Cornea 2015; 33:1324-31. [PMID: 25321938 DOI: 10.1097/ico.0000000000000281] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The aim of this study was to report a lattice corneal dystrophy (LCD) family with a novel mutation of A620P in the TGFBI gene, its long-term treatment, follow-up data, and related pathologic findings. METHODS A total of 28 family members were clinically examined, and blood samples or buccal epithelial cells were taken for DNA analysis. All exons from the entire TGFBI gene coding region were analyzed for mutations in 3 affected members. Exon 14 was amplified in other family members and in 100 normal Korean persons as control. Corneal tissues from 1 affected family member were examined using light and electron microscopy. RESULTS Clinical examination revealed relatively late-onset LCD with asymmetric progression and recurrent corneal erosion. The affected family members have been treated with penetrating keratoplasty, deep lamellar keratoplasty, and phototherapeutic keratectomy for up to 19 years. Screening of the TGFBI gene revealed a novel A620P mutation, which was found in all affected members. The amyloid origin of deposits was confirmed by Congo red and was also partially stained with Masson trichrome. Although there were no electron-dense bodies as in granular dystrophy, transmission electron microscopy demonstrated that the stromal deposits were not homogenous and contained a variety of constituents with different electron densities. CONCLUSIONS We present the characteristics and surgical treatment of corneas with a novel A620P mutation in TGFBI showing LCD type IIIA with hyaline component.
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Affiliation(s)
- Ji Won Jung
- *Department of Ophthalmology, Severance Hospital, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, Korea; †Department of Systems Biology, Yonsei University College of Life Science and Biotechnology, Seoul, Korea; and ‡Institute of Vision Research, Severance Biomedical Science Institute, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
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Choi SI, Maeng YS, Kim TI, Lee Y, Kim YS, Kim EK. Lysosomal trafficking of TGFBIp via caveolae-mediated endocytosis. PLoS One 2015; 10:e0119561. [PMID: 25853243 PMCID: PMC4390356 DOI: 10.1371/journal.pone.0119561] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Accepted: 01/10/2015] [Indexed: 11/18/2022] Open
Abstract
Transforming growth factor-beta-induced protein (TGFBIp) is ubiquitously expressed in the extracellular matrix (ECM) of various tissues and cell lines. Progressive accumulation of mutant TGFBIp is directly involved in the pathogenesis of TGFBI-linked corneal dystrophy. Recent studies reported that mutant TGFBIp accumulates in cells; however, the trafficking of TGFBIp is poorly understood. Therefore, we investigated TGFBIp trafficking to determine the route of its internalization and secretion and to elucidate its roles in the pathogenesis of granular corneal dystrophy type 2 (GCD2). Our data indicate that newly synthesized TGFBIp was secreted via the endoplasmic reticulum/Golgi-dependent secretory pathway, and this secretion was delayed in the corneal fibroblasts of patients with GCD2. We also found that TGFBIp was internalized by caveolae-mediated endocytosis, and the internalized TGFBIp accumulated after treatment with bafilomycin A1, an inhibitor of lysosomal degradation. In addition, the proteasome inhibitor MG132 inhibits the endocytosis of TGFBIp. Co-immunoprecipitation revealed that TGFBIp interacted with integrin αVβ3. Moreover, treatment with arginine-glycine-aspartic acid (RGD) tripeptide suppressed the internalization of TGFBIp. These insights on TGFBIp trafficking could lead to the identification of novel targets and the development of new therapies for TGFBI-linked corneal dystrophy.
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Affiliation(s)
- Seung-il Choi
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Yong-Sun Maeng
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
| | - Tae-im Kim
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
- Institute of Vision Research, Severance Biomedical Science Institute, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
| | - Yangsin Lee
- Department of Integrated Omics for Biomedical Science, Graduate School, Yonsei University, Seoul, South Korea
| | - Yong-Sun Kim
- Ilsong Institute of Life Science, Hallym University, Anyang, South Korea
- Department of Microbiology, College of Medicine, Hallym University, Chuncheon, South Korea
| | - Eung Kweon Kim
- Department of Ophthalmology, Corneal Dystrophy Research Institute, Yonsei University College of Medicine, Seoul, South Korea
- Institute of Vision Research, Severance Biomedical Science Institute, Brain Korea 21 Plus Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea
- * E-mail:
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Yoo YJ, Kim MK, Wee WR. Clinical Outcomes of Combined Photorefractive Keratectomy and Cataract Surgery in Patients with Granular Corneal Dystrophy. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2015. [DOI: 10.3341/jkos.2015.56.8.1170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Yung Ju Yoo
- Department of Ophthalmology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Mee Kum Kim
- Department of Ophthalmology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
- Biomedical Research Institute, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Won Ryang Wee
- Department of Ophthalmology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
- Biomedical Research Institute, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
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Foster J, Wu WH, Scott SG, Bassi M, Mohan D, Daoud Y, Stark WJ, Jun AS, Chakravarti S. Transforming growth factor β and insulin signal changes in stromal fibroblasts of individual keratoconus patients. PLoS One 2014; 9:e106556. [PMID: 25247416 PMCID: PMC4172437 DOI: 10.1371/journal.pone.0106556] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 08/07/2014] [Indexed: 11/19/2022] Open
Abstract
Keratoconus (KC) is a complex thinning disease of the cornea that often requires transplantation. The underlying pathogenic molecular changes in this disease are poorly understood. Earlier studies reported oxidative stress, metabolic dysfunctions and accelerated death of stromal keratocytes in keratoconus (KC) patients. Utilizing mass spectrometry we found reduced stromal extracellular matrix (ECM) proteins in KC, suggesting ECM-regulatory changes that may be due to altered TGFβ signals. Here we investigated properties of stromal cells from donor (DN) and KC corneas grown as fibroblasts in serum containing DMEM: F12 or in serum-free medium containing insulin, transferrin, selenium (ITS). Phosphorylation of SMAD2/3 of the canonical TGFβ pathway, was high in serum-starved DN and KC fibroblast protein extracts, but pSMAD1/5/8 low at base line, was induced within 30 minutes of TGFβ1 stimulation, more so in KC than DN, suggesting a novel TGFβ1-SMAD1/5/8 axis in the cornea, that may be altered in KC. The serine/threonine kinases AKT, known to regulate proliferation, survival and biosynthetic activities of cells, were poorly activated in KC fibroblasts in high glucose media. Concordantly, alcohol dehydrogenase 1 (ADH1), an indicator of increased glucose uptake and metabolism, was reduced in KC compared to DN fibroblasts. By contrast, in low glucose (5.5 mM, normoglycemic) serum-free DMEM and ITS, cell survival and pAKT levels were comparable in KC and DN cells. Therefore, high glucose combined with serum-deprivation presents some cellular stress difficult to overcome by the KC stromal cells. Our study provides molecular insights into AKT and TGFβ signal changes in KC, and a mechanism for functional studies of stromal cells from KC corneas.
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Affiliation(s)
- James Foster
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Wai-Hong Wu
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Sherri-Gae Scott
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Mehak Bassi
- All India Institute of Medical Sciences, New Delhi, India
| | - Divya Mohan
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Yassine Daoud
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Walter J. Stark
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Albert S. Jun
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Shukti Chakravarti
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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Choi SI, Maeng YS, Kim KS, Kim TI, Kim EK. Autophagy is induced by raptor degradation via the ubiquitin/proteasome system in granular corneal dystrophy type 2. Biochem Biophys Res Commun 2014; 450:1505-11. [DOI: 10.1016/j.bbrc.2014.07.035] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 07/05/2014] [Indexed: 11/30/2022]
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Gonzalez-Rodriguez J, Ramirez-Miranda A, Hernandez-Da Mota SE, Zenteno JC. TGFBI, CHST6, and GSN gene analysis in Mexican patients with stromal corneal dystrophies. Graefes Arch Clin Exp Ophthalmol 2014; 252:1267-72. [PMID: 24801599 DOI: 10.1007/s00417-014-2648-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Revised: 04/07/2014] [Accepted: 04/11/2014] [Indexed: 10/25/2022] Open
Abstract
OBJECTIVES The purpose of our study was to describe the results of molecular screening of TGFBI, CHST6, and GSN genes in a group of Mexican patients with different stromal corneal dystrophies (CD). MATERIAL AND METHODS A total of 16 CD Mexican patients pertaining to nine different pedigrees were subjected to a complete ophthalmological investigation. A clinical diagnosis of lattice CD was performed in 10 patients from five pedigrees. Three patients from two pedigrees were diagnosed with granular CD type 2, two patients with unrelated probands had Finnish-type corneal amyloidosis, and one patient had macular CD. Genetic analysis included DNA isolation from blood leukocytes and polymerase chain reaction (PCR) amplification and direct nucleotide sequencing of TGFBI, CHST6, and GSN genes. RESULTS Seven lattice CD patients from four unrelated families had an identical p.H626R mutation in TGFBI, three patients from a single lattice CD family carried a p.R124C substitution in TGFBI, and a granular type 2 CD pedigree was demonstrated to carry a heterozygous TGFBI p.M619K substitution. A patient having Finnish-type corneal amyloidosis had a p.D187N mutation in GSN. Finally, molecular analysis of CHST6 in a patient with macular CD disclosed the presence of a homozygous p.Y110C change. CONCLUSIONS This study improves the knowledge of the genetic features of Mexican patients with corneal stromal dystrophies by identifying mutations in the TGFBI, CHST6, and GSN genes. Genetic screening of larger samples of patients from distinct ethnic groups would be of great importance for a better understanding of the mutational spectrum of stromal CD.
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Affiliation(s)
- Johanna Gonzalez-Rodriguez
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
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Lakshminarayanan R, Chaurasia SS, Anandalakshmi V, Chai SM, Murugan E, Vithana EN, Beuerman RW, Mehta JS. Clinical and genetic aspects of the TGFBI-associated corneal dystrophies. Ocul Surf 2014; 12:234-51. [PMID: 25284770 DOI: 10.1016/j.jtos.2013.12.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 12/05/2013] [Accepted: 12/05/2013] [Indexed: 11/16/2022]
Abstract
Corneal dystrophies are a group of inherited disorders localized to various layers of the cornea that affect corneal transparency and visual acuity. The deposition of insoluble protein materials in the form of extracellular deposits or intracellular cysts is pathognomic. Mutations in TGFBI are responsible for superficial and stromal corneal dystrophies. The gene product, transforming growth factor β induced protein (TGFBIp) accumulates as insoluble deposits in various forms. The severity, clinicopathogenic variations, age of the onset, and location of the deposits depend on the type of amino acid alterations in the protein. Until 2006, 38 different pathogenic mutants were reported for the TGFBI-associated corneal dystrophies. This number has increased to 63 mutants, reported in more than 30 countries. There is no effective treatment to prevent, halt, or reverse the deposition of TGFBIp. This review presents a complete mutation update, classification of phenotypes, comprehensive reported incidents of various mutations, and current treatment options and their shortcomings. Future research directions and possible approaches to inhibiting disease progression are discussed.
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Affiliation(s)
- R Lakshminarayanan
- Singapore Eye Research Institute, Singapore; SRP Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore
| | - Shyam S Chaurasia
- Singapore Eye Research Institute, Singapore; SRP Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | - Shu-Ming Chai
- Singapore Eye Research Institute, Singapore; Singapore National Eye Centre, Singapore
| | | | - Eranga N Vithana
- Singapore Eye Research Institute, Singapore; SRP Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Roger W Beuerman
- Singapore Eye Research Institute, Singapore; SRP Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jodhbir S Mehta
- Singapore Eye Research Institute, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Singapore National Eye Centre, Singapore; Department of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore.
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Abstract
PURPOSE The purpose of this case report is to review granular corneal dystrophy (GCD) and examine the new paradigm in its classification and treatment. CASE REPORT A 49-year-old white male patient reported yearly for monitoring of GCD. He had an ocular surgical history in the left eye for penetrating keratoplasty in 1989 and phototherapeutic keratectomy with mitomycin C for graft recurrence of stromal bread-crumb opacities 17+ years later in 2002. At his last examination, the patient's vision and comfort was stable in each eye, with minimal recurrence of granular opacities in the left surgical eye, stable granular opacities in the right eye, no recurrent corneal erosion symptoms in either eye, and best spectacle-corrected vision of 20/40 OD and 20/30 OS. CONCLUSIONS GCD is a Category 1, Stromal, TGFBI-associated corneal dystrophy. Although it is classified as a stromal dystrophy, research suggests the possibility that the granular opacities have an origination to the corneal epithelium with a migratory effect to the corneal stroma. Patients with Groenouw I, like the one in this report, usually do not have severely compromised vision. When vision is significantly affected or recurrent corneal erosion occurs, despite first- and second-line treatments, viable management options thereafter include photokeratectomy and other new surgical treatments such as femtosecond deep anterior lamellar keratoplasty and femtosecond laser-assisted keratoplasty. Future advancements in diagnostic technology, immunohistologic and genetic testing, medications, and surgery will allow for advancements in treating and managing patients with GCD.
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Park YM, Kim HY, Lee JS. Confocal Microscopic Findings of Avellino Corneal Dystrophy According to Disease Severity. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2014. [DOI: 10.3341/jkos.2014.55.3.361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Young Min Park
- Department of Ophthalmology, Pusan National University Hospital, Pusan National University & Medical Research Institute, School of Medicine, Busan, Korea
| | - Ho Yun Kim
- Department of Ophthalmology, Pusan National University Hospital, Pusan National University & Medical Research Institute, School of Medicine, Busan, Korea
| | - Jong Soo Lee
- Department of Ophthalmology, Pusan National University Hospital, Pusan National University & Medical Research Institute, School of Medicine, Busan, Korea
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Changes of Clinical Manifestation of Granular Corneal Deposits Because of Recurrent Corneal Erosion in Granular Corneal Dystrophy Types 1 and 2. Cornea 2013; 32:e113-20. [DOI: 10.1097/ico.0b013e3182700620] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Choi SI, Kim KS, Oh JY, Jin JY, Lee GH, Kim EK. Melatonin induces autophagy via an mTOR-dependent pathway and enhances clearance of mutant-TGFBIp. J Pineal Res 2013; 54:361-72. [PMID: 23363291 DOI: 10.1111/jpi.12039] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 12/21/2012] [Indexed: 12/19/2022]
Abstract
The hallmark of granular corneal dystrophy type 2 (GCD2) is the deposit of mutant transforming growth factor-β (TGF-β)-induced protein (TGFBIp) in the cornea. We have recently shown that there is a delay in autophagic degradation of mutant-TGFBIp via impaired autophagic flux in GCD2 corneal fibroblasts. We hypothesized that melatonin can specifically induce autophagy and consequently eliminate mutant-TGFBIp in GCD corneal fibroblasts. Our results show that melatonin activates autophagy in both wild-type (WT) and GCD2-homozygous (HO) corneal fibroblast cell lines via the mammalian target of rapamycin (mTOR)-dependent pathway. Melatonin treatment also led to increased levels of beclin 1, which is involved in autophagosome formation and maturation. Furthermore, melatonin significantly reduced the amounts of mutant- and WT-TGFBIp. Treatment with melatonin counteracted the autophagy-inhibitory effects of bafilomycin A1, a potent inhibitor of autophagic flux, demonstrating that melatonin enhances activation of autophagy and increases degradation of TGFBIp. Cotreatment with melatonin and rapamycin, an autophagy inducer, had an additive effect on mutant-TGFBIp clearance compared to treatment with either drug alone. Treatment with the selective melatonin receptor antagonist luzindole did not block melatonin-induced autophagy. Given its ability to activate autophagy, melatonin is a potential therapeutic agent for GCD2.
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Affiliation(s)
- Seung-Il Choi
- Corneal Dystrophy Research Institute; Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea
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Cao W, Yan M, Hao Q, Wang S, Wu L, Liu Q, Li M, Biddle FG, Wu W. Autosomal-dominant Meesmann epithelial corneal dystrophy without an exon mutation in the keratin-3 or keratin-12 gene in a Chinese family. J Int Med Res 2013; 41:511-8. [PMID: 23569037 DOI: 10.1177/0300060513477306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Meesmann epithelial corneal dystrophy (MECD) is a dominantly inherited disorder, characterized by fragility of the anterior corneal epithelium and formation of intraepithelial microcysts. It has been described in a number of different ancestral groups. To date, all reported cases of MECD have been associated with either a single mutation in one exon of the keratin-3 gene (KRT3) or a single mutation in one of two exons of the keratin-12 gene (KRT12). Each mutation leads to a predicted amino acid change in the respective keratin-3 or keratin-12 proteins that combine to form the corneal-specific heterodimeric intermediate filament protein. This case report describes a four-generation Chinese kindred with typical autosomal-dominant MECD. Exon sequencing of KRT3 and KRT12 in six affected and eight unaffected individuals (including two spouses) did not detect any mutations or nucleotide sequence variants. This kindred demonstrates that single mis-sense mutations may be sufficient but are not required in all individuals with the MECD phenotype. It provides a unique opportunity to investigate further genomic and functional heterogeneity in MECD.
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Affiliation(s)
- Wei Cao
- Clinical Research Centre, People's Hospital of Zhengzhou, Zhengzhou, Henan, China.
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Mohammad-Rabei H, Shojaei A, Aslani M. Concurrent macular corneal dystrophy and keratoconus. Middle East Afr J Ophthalmol 2013; 19:251-3. [PMID: 22623870 PMCID: PMC3353679 DOI: 10.4103/0974-9233.95266] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
A 21-year-old female presented with progressive bilateral visual loss for the past 8 years. The patient had no history of systemic disease, surgery or medications. Complete ophthalmologic examination and topography were performed. On ophthalmic examination, uncorrected visual acuity was counting fingers at 2.5 m (20/50 with pinhole) in the right and left eyes. Both corneas appeared hazy on gross examination. On slit-lamp biomicroscopy, focal grayish-white opacities with indistinct borders were noted in the superficial and deep corneal stroma of both eyes. Both corneas were thin and bulging. Corneal topography showed a pattern consistent with keratoconus. The patient underwent penetrating keratoplasty (PKP). Histopathologic studies after PKP confirmed the diagnosis of macular corneal dystrophy and keratoconus in the same eye. The patient was clinically diagnosed as a case of concurrent macular dystrophy and keratoconus, which is a very rare presentation.
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Choi SI, Kim BY, Dadakhujaev S, Oh JY, Kim TI, Kim JY, Kim EK. Impaired autophagy and delayed autophagic clearance of transforming growth factor β-induced protein (TGFBI) in granular corneal dystrophy type 2. Autophagy 2012; 8:1782-97. [PMID: 22995918 DOI: 10.4161/auto.22067] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Granular corneal dystrophy type 2 (GCD2) is an autosomal dominant disease characterized by a progressive age-dependent extracellular accumulation of transforming growth factor β-induced protein (TGFBI). Corneal fibroblasts from GCD2 patients also have progressive degenerative features, but the mechanism underlying this degeneration remains unknown. Here we observed that TGFBI was degraded by autophagy, but not by the ubiquitin/proteasome-dependent pathway. We also found that GCD2 homozygous corneal fibroblasts displayed a greater number of fragmented mitochondria. Most notably, mutant TGFBI (mut-TGFBI) extensively colocalized with microtubule-associated protein 1 light chain 3β (MAP1LC3B, hereafter referred to as LC3)-enriched cytosolic vesicles and CTSD in primary cultured GCD2 corneal fibroblasts. Levels of LC3-II, a marker of autophagy activation, were significantly increased in GCD2 corneal fibroblasts. Nevertheless, levels of SQSTM1/p62 and of polyubiquitinated protein were also significantly increased in GCD2 corneal fibroblasts compared with wild-type (WT) cells. However, LC3-II levels did not differ significantly between WT and GCD2 cells, as assessed by the presence of bafilomycin A 1, the fusion blocker of autophagosomes and lysosomes. Likewise, bafilomycin A 1 caused a similar change in levels of SQSTM1. Thus, the increase in autophagosomes containing mut-TGFBI may be due to inefficient fusion between autophagosomes and lysosomes. Rapamycin, an autophagy activator, decreased mut-TGFBI, whereas inhibition of autophagy increased active caspase-3, poly (ADP-ribose) polymerase 1 (PARP1) and reduced the viability of GCD2 corneal fibroblasts compared with WT controls. These data suggest that defective autophagy may play a critical role in the pathogenesis of GCD2.
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Affiliation(s)
- Seung-Il Choi
- Corneal Dystrophy Research Institute and Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea
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Jeon ES, Kim JH, Ryu H, Kim EK. Lysophosphatidic acid activates TGFBIp expression in human corneal fibroblasts through a TGF-β1-dependent pathway. Cell Signal 2012; 24:1241-50. [DOI: 10.1016/j.cellsig.2012.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 02/14/2012] [Accepted: 02/14/2012] [Indexed: 11/24/2022]
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Abstract
Keratoconus is the most common ectatic disorder of the corneal. Genetic and environmental factors may contribute to its pathogenesis. The focus of this article is to summarize current research into the complex genetics of keratoconus. We discuss the evidence of genetic etiology including family-based linkage studies, twin studies, genetic mutations, and genome-wide association studies. The genes implicated potentially include VSX1, miR-184, DOCK9, SOD1, RAB3GAP1, and HGF. Besides the coding mutations, we also highlight the potential contribution of DNA copy number variants in the pathogenesis of keratoconus. Finally, we present future directions for genetic research in the understanding of the complex genetics of keratoconus and its clinical significance. As new functional, candidate genes for keratoconus are being discovered at a rapid pace, the molecular genetic mechanisms underlying keratoconus pathogenesis will advance our understanding of keratoconus and promote the development of a novel therapy.
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Affiliation(s)
- Joshua Wheeler
- Center for Human Genetics, Department of Medicine, Duke University Medical Center, Durham, NC, USA 27710
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Lee EJ, Kim KJ, Kim HN, Bok J, Jung SC, Kim EK, Lee JY, Kim HL. Genome-wide scan of granular corneal dystrophy, type II: confirmation of chromosome 5q31 and identification of new co-segregated loci on chromosome 3q26.3. Exp Mol Med 2011; 43:393-400. [PMID: 21628991 DOI: 10.3858/emm.2011.43.7.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Granular corneal dystrophy, type II (CGD2; Avellino corneal dystrophy) is the most common corneal dystrophy among Koreans, but its pathophysiology is still poorly understood. Many reports showed that even though the causative mutation is the same TGFBI R124H mutation, there are severe and mild phenotypes of the corneal dystrophy. We also observed the phenotype differences in our samples. For this reason, we focused our effort on the identification of unknown genetic factor related to phenotype variation. A total 551 individuals from 59 families were genotyped with SNP chip and used in genome-wide linkage analysis. From single-point linkage analyses, we confirmed the known 5q31 region for TGFBI gene, and selected novel nine candidate loci for CGD2. In simulation analysis, the only 3q26.3 region including neuroligin 1 gene (NLGN1) was supported by empirical statistic significance. To investigate the effect of genetic heterogeneity in linkage analysis, we classified CGD2 families into two subgroups. Although we could not find a significant evidence for correlation between the 3q26.3 region and CGD2 phenotypes, this first genome-wide analysis with CGD2 families in Korea has a very important value for offering insights in genetics of CGD2. In addition, the co-segregating loci with CGD2 including 3q26.3 would be a good target for further study to understand the pathophysiology of CGD2.
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Affiliation(s)
- Eun Ju Lee
- Department of Biochemistry School of Medicine Ewha Womans University Seoul, Korea
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Analysis of deposit depth and morphology in granular corneal dystrophy type 2 using fourier domain optical coherence tomography. Cornea 2011; 30:729-38. [PMID: 21242786 DOI: 10.1097/ico.0b013e3182000933] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Granular corneal dystrophy type 2 (GCD2) causes the formation of corneal deposits having 3 different morphological types. We used Fourier domain optical coherence tomography to assess the depths of each type according to the morphology. METHODS A prospective study was performed in 54 eyes of 54 heterozygous patients with GCD2. Corneal deposits of 54 patients with GCD2 were classified into 3 morphological types: type 1, diffuse haze; type 2, granular shape (2 subgroups: type 2a, round granulated and type 2b, round spiculated); and type 3, linear shape (2 subgroups: type 3a, short side branched and type 3b, long side branched). Using Fourier domain optical coherence tomography, we measured the distances from the Bowman layer to the upper surface of the deposits (USBL), to the lower surface of the deposits (LSBL), and the thickness of the deposits (TD). The deposits formed along the flap interface were also examined among 19 patients who had LASIK. RESULTS Types 1 and 2 deposits were always adjacent to the Bowman layer; thus the USBLs for each were 0.0 ± 0.0 μm, whereas that of type 3 deposits was 65.4 ± 48.0 μm (P < 0.0001). The LSBL and TD of linear deposits with long side branches (type 3) (313.3 ± 71.4 and 246.2 ± 71.9 μm) were greater than those of type 1 (47.7 ± 10.2 and 47.7 ± 10.2 μm) and type 2 (91.3 ± 39.5 and 91.3 ± 39.5 μm) (P < 0.0001). There were no differences in the measurements between the subgroups type 2a and type 2b or between types 3a and 3b. USBL of the laser in situ keratomileusis group was 54.5 ± 29.8 μm. CONCLUSIONS The depths of corneal deposits in patients with GCD2 were associated with the morphology of the deposits. The linear deposits were located most deeply in the cornea, followed by granular deposits and diffuse haze moving anteriorly. Several deposits have distinct depths according to the morphological types.
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Choi SI, Dadakhujaev S, Ryu H, Im Kim T, Kim EK. Melatonin protects against oxidative stress in granular corneal dystrophy type 2 corneal fibroblasts by mechanisms that involve membrane melatonin receptors. J Pineal Res 2011; 51:94-103. [PMID: 21392093 DOI: 10.1111/j.1600-079x.2011.00866.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Considering that oxidative stress plays a role in corneal fibroblast degeneration during granular corneal dystrophy type 2 (GCD2) and melatonin is an effective antioxidant, we examined the ability of melatonin to protect against oxidative stress-induced cell death of primary cultured normal and GCD2-homozygous corneal fibroblasts. Melatonin treatment protected primary cultured normal and GCD2 corneal fibroblasts from paraquat (PQ)-induced oxidative stress and caused increased expression levels of Cu/Zn-superoxide dismutase (SOD1) and glutathione reductase (GR) in both types of cells. Interestingly, catalase expression increased in normal corneal fibroblasts, but decreased in GCD2 corneal fibroblasts after melatonin treatment. Melatonin also reduced the levels of intracellular reactive oxygen species and H(2)O(2) in both cell types. In addition, the selective melatonin receptor antagonist luzindole blocked melatonin-induced expression of SOD1 and GR. The expression levels of melatonin receptors 1A (MT1) and 1B (MT2) were significantly higher in GCD2 corneal fibroblasts than in normal cells. These results suggest that increased expression of melatonin receptors may be involved in the defense mechanisms against oxidative stress in GCD2 corneal fibroblasts, and melatonin may have potential therapeutic implications for GCD2 treatment.
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Kim TI, Kim H, Lee DJ, Choi SI, Kang SW, Kim EK. Altered mitochondrial function in type 2 granular corneal dystrophy. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 179:684-92. [PMID: 21699880 DOI: 10.1016/j.ajpath.2011.04.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 03/15/2011] [Accepted: 04/18/2011] [Indexed: 12/31/2022]
Abstract
Type 2 granular corneal dystrophy (GCD2) is caused by point mutation R124H in the transforming growth factor-β-induced gene (TGFBI) and is characterized by age-dependent progression of corneal deposits. Mitochondrial features in heterozygous GCD2 and normal corneal tissues was evaluated using electron microscopy. Primary corneal fibroblasts of homozygous and normal corneas were cultured to passage 4 or 8. Keratocytes of normal corneal tissue are narrow, and details of their intracellular organelles are difficult to distinguish. Keratocytes of heterozygous GCD2 tissues exhibited many degenerative mitochondria. MitoTracker and cytochrome c staining demonstrated increased mitochondrial activity in mutated cells at early passages. Decreases in depolarized mitochondria, cellular proliferation, and expression of complexes I to V and increases in apoptotic change were observed in late-passage mutant fibroblasts. PGC-1α, ANT-1, p-Akt, and p-mTOR but not NF-κB expression demonstrated a passage-dependent decrease in all cells. Increased passage- or mutation-related intracellular reactive oxygen species and delayed proliferation of methanethiosulfonate (MTS) were recovered using application of antioxidant butylated hydroxyanisole. Mitochondrial features and function were altered in mutated GCD2 keratocytes, in particular in older cells. Alteration of mitochondrial function is critical for understanding the pathogenesis of GCD2.
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Affiliation(s)
- Tae-im Kim
- Corneal Dystrophy Research Institute, the Department of Ophthalmology, Yonsei University College of Medicine, Seoul, South Korea
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Long Y, Gu YS, Han W, Li XY, Yu P, Qi M. Genotype-phenotype correlations in Chinese patients with TGFBI gene-linked corneal dystrophy. J Zhejiang Univ Sci B 2011; 12:287-92. [PMID: 21462384 DOI: 10.1631/jzus.b1000154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this paper, we report the clinical and molecular features of the distinct TGFBI (human transforming growth factor β-induced, OMIM No. 601692) gene-linked corneal dystrophy. Altogether, five pedigrees and ten unrelated individuals diagnosed as corneal dystrophy were recruited. Peripheral venous DNA was extracted, and then amplified by polymerase chain reaction (PCR) and scanned for mutation by single-stranded conformation polymorphism (SSCP). Direct DNA sequencing was used to analyze the mutations of the TGFBI gene. In our study, thirty patients from five pedigrees and ten sporadic patients were diagnosed as four TGFBI gene-linked corneal dystrophies of granular corneal dystrophy type I (GGCD I), Avellino corneal dystrophy (ACD), lattice corneal dystrophy type I (LCD I), and lattice corneal dystrophy type IIIA (LCD IIIA), and in total, seven disease-causing mutations, namely R555W, A546D, A546T, and T538P mutations in exon 12, R124H and R124C mutations in exon 4, and P501T mutation in exon 11, were identified, while four polymorphisms of V327V, L472L, F540F, and 1665-1666insC were screened in exons 8, 11, and 12. The study ascertained the tight genotype-phenotype relationship and confirmed the clinical and genetic features of four TGFBI gene-linked corneal dystrophies.
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Affiliation(s)
- Yan Long
- Department of Ophthalmology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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44
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Abstract
PURPOSE Both granular and lattice deposits are present in Avellino corneal dystrophy (ACD), primarily associated with the R124H mutation of transforming growth factor-β-induced (TGFBIp). We investigated the presence of these deposits in other TGFBI mutations and the use of Thioflavin-T (ThT), a fluorescent amyloid stain for characterizing corneal amyloid deposits. METHODS Surgical corneal specimens of 3 unrelated patients clinically diagnosed with ACD were studied. Corneal sections from normal individuals and patients with prior lattice corneal dystrophy (LCD) were used as controls. Histochemical studies were performed with Congo red and Masson trichrome stains, and fluorescent imaging with scanning laser confocal microscopy was performed for ThT and anti-TGFBIp antibody staining. RESULTS Clinical and histopathological findings supported the diagnoses of ACD in these 3 cases in whom granular deposits stained with Masson trichrome and lattice deposits stained with ThT and Congo red showed birefringence and dichroism as expected. However, genotyping revealed a heterozygous R124C mutation in each case. In addition to classical stromal deposits, unique subepithelial TGFBIp aggregates, which stain with neither ThT nor trichrome, were observed. In control LCD sections, stromal deposits were stained with ThT but not with trichrome, confirming lack of granular deposits. CONCLUSIONS Our results demonstrate that both granular and lattice corneal deposits can be associated with R124C mutation in addition to the more common R124H mutation. An additional feature of nonhyaline, nonamyloid, TGFBIp subepithelial deposits might substantiate the categorization of such cases as a variant form of ACD. This study further validates ThT staining for detection of amyloid TGFBIp deposits.
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SAXS models of TGFBIp reveal a trimeric structure and show that the overall shape is not affected by the Arg124His mutation. J Mol Biol 2011; 408:503-13. [PMID: 21371477 DOI: 10.1016/j.jmb.2011.02.052] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Revised: 02/21/2011] [Accepted: 02/23/2011] [Indexed: 11/23/2022]
Abstract
Human transforming growth factor β induced protein (TGFBIp) is composed of 683 residues, including an N-terminal cysteine-rich (EMI) domain, four homologous fasciclin domains, and an Arg-Gly-Asp (RGD) motif near the C-terminus. The protein is of interest because mutations in the TGFBI gene encoding TGFBIp lead to corneal dystrophy (CD), a condition where protein aggregates within the cornea compromise transparency. The complete three-dimensional structure of TGFBIp is not yet available, with the exception of a partial X-ray structure of the archetype FAS1 domain derived from Drosophila fasciclin-1. In this study, small-angle X-ray scattering (SAXS) models of intact wild-type (WT) human TGFBIp and a mutant (R124H) are presented. The mutation R124H leads to a variant of granular CD. The deduced structure of the TGFBIp monomer consists of four FAS1 domains in a simple "beads-on-a-string" arrangement, constructed by the superimposition of four consecutive Drosophila fasciclin domains. The SAXS-based model of the TGFBIp R124H mutant displayed no structural differences from WT. Both WT TGFBIp and the R124H mutant formed trimers at higher protein concentrations. The similar association properties and three-dimensional shape of the two proteins suggest that the mutation does not induce any major structural rearrangements, but points towards the role of other corneal-specific factors in the formation of corneal R124H deposits.
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Pedersen JS, Andersen CB, Otzen DE. Amyloid structure--one but not the same: the many levels of fibrillar polymorphism. FEBS J 2010; 277:4591-601. [PMID: 20977663 DOI: 10.1111/j.1742-4658.2010.07888.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Many proteins and peptides can form amyloid-like structures both in vivo and in vitro. Although strikingly similar fibrillar structures can be observed across a variety of amino acid sequences, the fibrils formed often exhibit a stunning wealth of polymorphisms at the level of electron or atomic force microscopy. This appears to violate the Anfinsen principle seen for globular proteins, where each protein sequence codes for just one well-defined fold. To a large extent, polymorphism reflects variable packing of a single protofilament structure in the mature fibrils. However, we and others have recently demonstrated that polymorphism can also reflect real structural differences in the molecular packing of the polypeptide chains leading to several possible protofilament structures and diverse mature fibrillar structures. Glucagon has been a particularly useful model system for studying the fibrillogenesis mechanisms that lead to the formation of structural polymorphism, thanks to its single tryptophan residue and the availability of large quantities at pharmaceutical-grade quality. Combinations of structural investigations and seed extension experiments have revealed the reproducible formation of at least five different self-propagating fibril types from subtle variations in growth conditions. These reflect the underlying complexity of the peptide conformational landscape and provide a link to natively disordered proteins, where structure is dictated by context in the form of different binding partners. Here we review some of the latest advances in the study of glucagon fibrillar polymorphism and their implications for mechanisms of fibril formation in general.
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Affiliation(s)
- Jesper S Pedersen
- Department of Biochemistry, Molecular Biology, and Cell Biology, Rice Institute for Biomedical Research, Northwestern University, Evanston, IL 60208, USA.
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Lee JH, Cristol SM, Kim WC, Chung ES, Tchah H, Kim MS, Nam CM, Cho HS, Kim EK. Prevalence of granular corneal dystrophy type 2 (Avellino corneal dystrophy) in the Korean population. Ophthalmic Epidemiol 2010; 17:160-5. [PMID: 20455845 DOI: 10.3109/09286581003624939] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE This study investigates the prevalence of granular corneal dystrophy type 2 (GCD2; Avellino corneal dystrophy) in the Korean population. METHODS GCD2 homozygotes were identified through a collaboration of Korean referral centers for corneal disease. The genetic status of the patients and their immediate families were verified by DNA analysis. A lower bound for the gene prevalence was calculated using a model based on the Hardy-Weinberg principle. A second population-based model was developed to correct for known underestimation in the primary model. The corrected model used population data from the 2005 Korean census and fertility rates from historical Korean census data. RESULTS We identified 21 individuals homozygous for GCD2 (R124H mutation) from 16 Korean families. From this, we estimate that the overall prevalence (combining heterozygotes and homozygotes) is at least 8.25 affected persons/10,000 persons. Our corrected estimate for overall prevalence is 11.5 affected persons/10,000 persons. CONCLUSION We present the first estimate of the prevalence of GCD2. Although uncommon, the prevalence of GCD2 in Korea is greater than anticipated. We believe that our approach could potentially be applied to estimating the prevalence of other rare diseases.
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Affiliation(s)
- Jae Hwan Lee
- Corneal Dystrophy Research Institute, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
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Mitomycin C Does Not Inhibit Exacerbation of Granular Corneal Dystrophy Type II Induced by Refractive Surface Ablation. Cornea 2010; 29:490-6. [DOI: 10.1097/ico.0b013e3181c3258a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Cholesterol crystals piercing the arterial plaque and intima trigger local and systemic inflammation. J Clin Lipidol 2010; 4:156-64. [PMID: 21122648 DOI: 10.1016/j.jacl.2010.03.003] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 03/03/2010] [Accepted: 03/05/2010] [Indexed: 11/20/2022]
Abstract
The response to arterial wall injury is an inflammatory process, which over time becomes integral to the development of atherosclerosis and subsequent plaque instability. However, the underlying injurious agent, critical to this process, has not received much attention. In this review, a model of plaque rupture is hypothesized with two stages of inflammatory activity. In stage I (cholesterol crystal-induced cell injury and apoptosis), intracellular cholesterol crystals induce foam cell apoptosis, setting up a vicious cycle by signaling more macrophages, resulting in accumulation of extra cellular lipids. This local inflammation eventually leads to the formation of a semi-liquid, lipid-rich necrotic core of a vulnerable plaque. In stage II (cholesterol crystal-induced arterial wall injury), the saturated lipid core is now primed for crystallization, which can manifest as a clinical syndrome with a systemic inflammation response. Cholesterol crystallization is the trigger that causes core expansion, leading to intimal injury. We recently demonstrated that when cholesterol crystallizes from a liquid to a solid state, it undergoes volume expansion, which can tear the plaque cap. This observation of cholesterol crystals perforating the cap and intimal surface was made in the plaques of patients who died with acute coronary syndrome. We have also demonstrated that several agents (ie, statins, aspirin, and ethanol) can dissolve cholesterol crystals and may be exerting their immediate benefits by this direct mechanism. Also, because recent studies have demonstrated that high-sensitivity C-reactive protein may be a reliable marker in selecting patients for statin therapy, it could reflect the presence of intimal injury by cholesterol crystals. This was demonstrated in an atherosclerotic rabbit model. Therefore, we propose that cholesterol crystallization could help explain in part both local and systemic inflammation associated with atherosclerosis.
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Identification of genome-wide copy number variations and a family-based association study of Avellino corneal dystrophy. Ophthalmology 2010; 117:1306-12.e4. [PMID: 20202685 DOI: 10.1016/j.ophtha.2009.11.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2009] [Revised: 11/11/2009] [Accepted: 11/12/2009] [Indexed: 12/27/2022] Open
Abstract
OBJECTIVE To determine the association of identified copy number variations (CNVs) in whole genome with the risk of Avellino corneal dystrophy (ACD) in a Korean population. DESIGN Case-control study. PARTICIPANTS A total of 146 patients with ACD and 226 control subjects. METHODS A total of 193 trios were genotyped by the Illumina HumanHapCNV370-Duo BeadChip (370,404 markers) (Illumina, Inc., San Diego, CA). The intensity signal (log R ratio) and allelic intensity ratio (B allele frequency) of each marker in all individuals were obtained by Illumina BeadStudio software (Illumina, Inc.). To obtain authentic CNVs in this study, we performed a family-based CNV validation and family-based boundary mapping using the PennCNV algorithm, which incorporates multiple factors, including total log R ratio, B allele frequency, and family information, based on an integrated hidden Markov model. MAIN OUTCOME MEASURES Statistical comparison and identification of CNVs between case and control using family information. RESULTS We identified 27,267 individual trio CNVs with a median size of 16.2 kb, aggregated in 2245 CNV regions. Most of the identified trio CNVs in this study showed well-defined CNV boundaries and overlapped with those in the Database of Genomic Variants (DGV) (83.4% in number and 79.2% in length). With the common CNV regions (264 CNV regions >5%), we performed a family-based association test with the risk of ACD. CONCLUSIONS Two CNV regions (chr6:29978470-29987783 and chr14:59896944-59916129) were significantly associated with the risk of ACD (P=0.05-0.003 and P=0.008, respectively). This study describes the first results of a genome-wide association analysis of individual CNVs with the risk of ACD and shows that 2 novel CNV loci may be involved in the risk of ACD. FINANCIAL DISCLOSURE(S) The author(s) have no proprietary or commercial interest in any materials discussed in this article.
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