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Sharma R, Kumari A, Kundu B, Grover A. Amyloid fibrillation of the glaucoma associated myocilin protein is inhibited by epicatechin gallate (ECG). RSC Adv 2022; 12:29469-29481. [PMID: 36320765 PMCID: PMC9562371 DOI: 10.1039/d2ra05061g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 09/18/2022] [Indexed: 11/05/2022] Open
Abstract
Inherited glaucoma is a recent addition to the inventory of diseases arising due to protein misfolding. Mutations in the olfactomedin (OLF) domain of myocilin are the most common genetic cause behind this disease. Disease associated variants of m-OLF are predisposed to misfold and aggregate in the trabecular meshwork (TM) tissue of the eye. In recent years, the nature of these aggregates was revealed to exhibit the hallmarks of amyloids. Amyloid aggregates are highly stable structures that are formed, often with toxic consequences in a number of debilitating diseases. In spite of its clinical relevance the amyloidogenic nature of m-OLF has not been studied adequately. Here we have studied the amyloid fibrillation of m-OLF and report ECG as an inhibitor against it. Using biophysical and biochemical assays, coupled with advanced microscopic evaluations we show that ECG binds and stabilizes native m-OLF and thus prevents its aggregation into amyloid fibrils. Furthermore, we have used REMD simulations to delineate the stabilizing effects of ECG on the structure of m-OLF. Collectively, we report ECG as a molecular scaffold for designing and testing of novel inhibitors against m-OLF amyloid fibrillation.
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Affiliation(s)
- Ritika Sharma
- School of Biotechnology, Jawaharlal Nehru UniversityNew Delhi-110067India+91-8130738032
| | - Anchala Kumari
- Indian Council of Medical Research, International Health DivisionNew Delhi-110029India
| | - Bishwajit Kundu
- Kusuma School of Biological Sciences, Indian Institute of Technology DelhiHauz KhasNew DelhiIndia – 110016
| | - Abhinav Grover
- School of Biotechnology, Jawaharlal Nehru UniversityNew Delhi-110067India+91-8130738032
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Criscione J, Ji W, Jeffries L, McGrath JM, Soloway S, Pusztai L, Lakhani S. Identification of a novel MYOC variant in a Hispanic family with early-onset primary open-angle glaucoma with elevated intraocular pressure. Cold Spring Harb Mol Case Stud 2019; 5:mcs.a004374. [PMID: 31653660 PMCID: PMC6913140 DOI: 10.1101/mcs.a004374] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 08/09/2019] [Indexed: 12/18/2022] Open
Abstract
Primary open-angle glaucoma (POAG) is the leading cause of irreversible blindness worldwide. Most cases are multifactorial in etiology, but some are associated with variants in the myocilin gene, MYOC. Here, we report the identification of a novel MYOC variant, c.1153G>A, in a 24-yr-old female patient with a personal and family history of juvenile/early-onset POAG. Further genetic testing within her family demonstrated that this variant segregates with the POAG phenotype in an autosomal dominant pattern. Identification of this MYOC variant in multiple affected relatives provides evidence for its pathogenicity, supporting previous findings linking MYOC mutations, in particular in the third exon's olfactomedin domain, to juvenile-onset POAG. This case also emphasizes the potential value of genetic testing in families with histories of eye disorders.
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Affiliation(s)
- June Criscione
- Pediatric Genomics Discovery Program, Department of Pediatrics, Genomics, and Epigenetics Program, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Weizhen Ji
- Pediatric Genomics Discovery Program, Department of Pediatrics, Genomics, and Epigenetics Program, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Lauren Jeffries
- Pediatric Genomics Discovery Program, Department of Pediatrics, Genomics, and Epigenetics Program, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - James M McGrath
- Department of Genetics, Genomics, and Epigenetics Program, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Scott Soloway
- Department of Ophthalmology, Genomics, and Epigenetics Program, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Lajos Pusztai
- Yale Cancer Center Genetics, Genomics, and Epigenetics Program, Yale University School of Medicine, New Haven, Connecticut 06520, USA
| | - Saquib Lakhani
- Pediatric Genomics Discovery Program, Department of Pediatrics, Genomics, and Epigenetics Program, Yale University School of Medicine, New Haven, Connecticut 06520, USA
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Different Grp94 components interact transiently with the myocilin olfactomedin domain in vitro to enhance or retard its amyloid aggregation. Sci Rep 2019; 9:12769. [PMID: 31484937 PMCID: PMC6726633 DOI: 10.1038/s41598-019-48751-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 08/07/2019] [Indexed: 01/04/2023] Open
Abstract
The inherited form of open angle glaucoma arises due to a toxic gain-of-function intracellular misfolding event involving a mutated myocilin olfactomedin domain (OLF). Mutant myocilin is recognized by the endoplasmic reticulum (ER)-resident heat shock protein 90 paralog, glucose regulated protein 94 (Grp94), but their co-aggregation precludes mutant myocilin clearance by ER-associated degradation. When the Grp94-mutant myocilin interaction is abrogated by inhibitors or siRNA, mutant myocilin is efficiently degraded. Here we dissected Grp94 into component domains (N, NM, MC) to better understand the molecular factors governing its interaction with OLF. We show that the Grp94 N-terminal nucleotide-binding N domain is responsible for accelerating OLF aggregation in vitro. Upon inhibiting the isolated N domain pharmacologically or removing the Pre-N terminal 57 residues from full-length Grp94, OLF aggregation rates revert to those seen for OLF alone, but only pharmacological inhibition rescues co-aggregation. The Grp94-OLF interaction is below the detection limit of fluorescence polarization measurements, but chemical crosslinking paired with mass spectrometry analyses traps a reproducible interaction between OLF and the Grp94 N domain, as well as between OLF and the Grp94 M domain. The emerging molecular-level picture of quinary interactions between Grp94 and myocilin points to a role for the far N-terminal sequence of the Grp94 N domain and a cleft in the M domain. Our work further supports drug discovery efforts to inhibit these interactions as a strategy to treat myocilin-associated glaucoma.
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Wang H, Li M, Zhang Z, Xue H, Chen X, Ji Y. Physiological function of myocilin and its role in the pathogenesis of glaucoma in the trabecular meshwork (Review). Int J Mol Med 2018; 43:671-681. [PMID: 30483726 PMCID: PMC6317685 DOI: 10.3892/ijmm.2018.3992] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Accepted: 11/16/2018] [Indexed: 12/26/2022] Open
Abstract
Myocilin is highly expressed in the trabecular meshwork (TM), which plays an important role in the regulation of intraocular pressure (IOP). Myocilin abnormalities may cause dysfunction of the TM, potentially leading to increased IOP. High IOP is a well‑known primary risk factor for glaucoma. Myocilin mutations are common among glaucoma patients, and they are implicated in juvenile‑onset open‑angle glaucoma (JOAG) and adult‑onset primary open‑angle glaucoma (POAG). Aggregation of aberrant mutant myocilins is closely associated with glaucoma pathogenesis. The aim of the present review was to discuss the recent findings regarding the major physiological functions of myocilin, such as intra‑ and extracellular proteolytic processes. We also aimed to discuss the risk factors associated with myocilin and the development of glaucoma, such as misfolded/mutant myocilin, imbalance of myocilin and extracellular proteins, and instability of mutant myocilin associated with temperature. Finally, we further outlined certain issues that are yet to be resolved, which may represent the basis for future studies on the role of myocilin in glaucoma.
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Affiliation(s)
- Hongwei Wang
- Department of Ophthalmology, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
| | - Mingzhe Li
- Department of Ophthalmology, Shanghai Pudong Hospital, Fudan University Pudong Medical Center, Shanghai 201399, P.R. China
| | - Zhenzhen Zhang
- Department of Ophthalmology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011, P.R. China
| | - Haifeng Xue
- Public Health School, Qiqihar Medical University, Qiqihar, Heilongjiang 161006, P.R. China
| | - Xing Chen
- Department of Science and Education, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
| | - Yong Ji
- Department of General Surgery, Jingjiang People's Hospital, Jingjiang, Jiangsu 214500, P.R. China
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