1
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Zhang X, Xi G, Feng P, Li C, Kuehn MH, Zhu W. Intraocular pressure across the lifespan of Tg-MYOC Y437H mice. Exp Eye Res 2024; 241:109855. [PMID: 38453040 DOI: 10.1016/j.exer.2024.109855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2024] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/09/2024]
Abstract
Transgenic C57BL/6 mice expressing human myocilinY437 (Tg-MYOCY437H) are a well-established model for primary open-angle glaucoma (POAG). While the reduced trabecular meshwork (TM) cellularity due to severe endoplasmic reticulum (ER) stress has been characterized as the etiology of this model, there is a limited understanding of how glaucomatous phenotypes evolve over the lifespan of Tg-MyocY437H mice. In this study, we compiled the model's intraocular pressure (IOP) data recorded in our laboratory from 2017 to 2023 and selected representative eyes to measure the outflow facility (Cr), a critical parameter indicating the condition of the conventional TM pathway. We found that Tg-MYOCY437H mice aged 4-12 months exhibited significantly higher IOPs than age-matched C57BL/6 mice. Notably, a decline in IOP was observed in Tg-MYOCY437H mice at 17-24 months of age, a phenomenon not attributable to the gene dosage of mutant myocilin. Measurements of the Cr of Tg-MYOCY437H mice indicated that the age-related IOP reduction was not a result of ongoing TM damage. Instead, Hematoxylin and Eosin staining, immunohistochemistry analysis, and transmission electron microscopic examination revealed that this reduction might be induced by degenerations of the non-pigmented epithelium in the ciliary body of aged Tg-MYOCY437H mice. Overall, our findings provide a comprehensive profile of mutant myocilin-induced ocular changes over the Tg-MYOCY437H mouse lifespan and suggest a specific temporal window of elevated IOP that may be ideal for experimental purposes.
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Affiliation(s)
- Xiaoyan Zhang
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, 266021, China
| | - Gaiping Xi
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, 266021, China
| | - Pengchao Feng
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, 266021, China
| | - Cong Li
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, 266021, China
| | - Markus H Kuehn
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, 52242, USA; Center for the Prevention and Treatment of Visual Loss, Iowa City Veterans Affairs Medical Center, Iowa City, IA, 52246, USA
| | - Wei Zhu
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, 266021, China; Advanced Innovation Center for Big Data-Based Precision Medicine, Beijing University of Aeronautics and Astronautics, Capital Medical University, Beijing, 100083, China.
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2
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Patil SV, Kaipa BR, Ranshing S, Sundaresan Y, Millar JC, Nagarajan B, Kiehlbauch C, Zhang Q, Jain A, Searby CC, Scheetz TE, Clark AF, Sheffield VC, Zode GS. Lentiviral mediated delivery of CRISPR/Cas9 reduces intraocular pressure in a mouse model of myocilin glaucoma. Sci Rep 2024; 14:6958. [PMID: 38521856 PMCID: PMC10960846 DOI: 10.1038/s41598-024-57286-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 03/16/2024] [Indexed: 03/25/2024] Open
Abstract
Mutations in myocilin (MYOC) are the leading known genetic cause of primary open-angle glaucoma, responsible for about 4% of all cases. Mutations in MYOC cause a gain-of-function phenotype in which mutant myocilin accumulates in the endoplasmic reticulum (ER) leading to ER stress and trabecular meshwork (TM) cell death. Therefore, knocking out myocilin at the genome level is an ideal strategy to permanently cure the disease. We have previously utilized CRISPR/Cas9 genome editing successfully to target MYOC using adenovirus 5 (Ad5). However, Ad5 is not a suitable vector for clinical use. Here, we sought to determine the efficacy of adeno-associated viruses (AAVs) and lentiviruses (LVs) to target the TM. First, we examined the TM tropism of single-stranded (ss) and self-complimentary (sc) AAV serotypes as well as LV expressing GFP via intravitreal (IVT) and intracameral (IC) injections. We observed that LV_GFP expression was more specific to the TM injected via the IVT route. IC injections of Trp-mutant scAAV2 showed a prominent expression of GFP in the TM. However, robust GFP expression was also observed in the ciliary body and retina. We next constructed lentiviral particles expressing Cas9 and guide RNA (gRNA) targeting MYOC (crMYOC) and transduction of TM cells stably expressing mutant myocilin with LV_crMYOC significantly reduced myocilin accumulation and its associated chronic ER stress. A single IVT injection of LV_crMYOC in Tg-MYOCY437H mice decreased myocilin accumulation in TM and reduced elevated IOP significantly. Together, our data indicates, LV_crMYOC targets MYOC gene editing in TM and rescues a mouse model of myocilin-associated glaucoma.
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Affiliation(s)
- Shruti V Patil
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX, 76107, USA
| | - Balasankara Reddy Kaipa
- Department of Ophthalmology and Center for Translational Vision Research, University of California, 829 Health Sciences Rd, Irvine, CA, 92617, USA
| | - Sujata Ranshing
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX, 76107, USA
| | - Yogapriya Sundaresan
- Department of Ophthalmology and Center for Translational Vision Research, University of California, 829 Health Sciences Rd, Irvine, CA, 92617, USA
| | - J Cameron Millar
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX, 76107, USA
| | - Bhavani Nagarajan
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX, 76107, USA
| | - Charles Kiehlbauch
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX, 76107, USA
| | - Qihong Zhang
- Department of Pediatrics, University of Iowa, Iowa City, IA, 52242, USA
| | - Ankur Jain
- Department of Pediatrics, University of Iowa, Iowa City, IA, 52242, USA
| | - Charles C Searby
- Department of Pediatrics, University of Iowa, Iowa City, IA, 52242, USA
| | - Todd E Scheetz
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, 52242, USA
| | - Abbot F Clark
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX, 76107, USA
| | - Val C Sheffield
- Department of Pediatrics, University of Iowa, Iowa City, IA, 52242, USA
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, 52242, USA
| | - Gulab S Zode
- Department of Ophthalmology and Center for Translational Vision Research, University of California, 829 Health Sciences Rd, Irvine, CA, 92617, USA.
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3
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Loo Y, Chan ASY, Khor CC, Aung T, Wang Z. Rodent genetically modified models of glaucoma. Mol Aspects Med 2024; 95:101229. [PMID: 38039744 DOI: 10.1016/j.mam.2023.101229] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 11/11/2023] [Accepted: 11/15/2023] [Indexed: 12/03/2023]
Abstract
Glaucoma, one of the leading causes of irreversible blindness worldwide, is a complex and heterogenous disease. While environmental factors are important, it is well-recognized that the disease has a strong heritable component. With the advent of large-cohort genome wide association studies, a myriad of genetic risk loci has been linked to different forms of glaucoma. Animal models have been an indispensable tool in characterizing these loci, especially if they lie within coding regions in the genome. Not only do these models connect genotype to phenotype, advancing our understanding of glaucoma pathogenesis in the process, they also have valuable utility as a platform for the pre-clinical testing of potential therapies. In this review, we will outline genetic models used for studying the major forms of glaucoma, including primary open angle glaucoma, normal tension glaucoma, primary angle closure glaucoma, pigmentary glaucoma, pseudoexfoliation glaucoma, and early onset glaucoma, including congenital and developmental glaucoma, and how studying these models have helped shed light on human glaucoma.
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Affiliation(s)
- Yunhua Loo
- Duke-NUS Medical School, Singapore; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Anita Sook Yee Chan
- Duke-NUS Medical School, Singapore; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Chiea Chuen Khor
- Duke-NUS Medical School, Singapore; Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Tin Aung
- Duke-NUS Medical School, Singapore; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Zhenxun Wang
- Duke-NUS Medical School, Singapore; Genome Institute of Singapore, Agency for Science, Technology and Research, Singapore; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
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4
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Patil SV, Kaipa BR, Ranshing S, Sundaresan Y, Millar JC, Nagarajan B, Kiehlbauch C, Zhang Q, Jain A, Searby CC, Scheetz TE, Clark AF, Sheffield VC, Zode GS. Lentiviral mediated delivery of CRISPR/Cas9 reduces intraocular pressure in a mouse model of myocilin glaucoma. RESEARCH SQUARE 2023:rs.3.rs-3740880. [PMID: 38196579 PMCID: PMC10775399 DOI: 10.21203/rs.3.rs-3740880/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Mutations in myocilin (MYOC) are the leading known genetic cause of primary open-angle glaucoma, responsible for about 4% of all cases. Mutations in MYOC cause a gain-of-function phenotype in which mutant myocilin accumulates in the endoplasmic reticulum (ER) leading to ER stress and trabecular meshwork (TM) cell death. Therefore, knocking out myocilin at the genome level is an ideal strategy to permanently cure the disease. We have previously utilized CRISPR/Cas9 genome editing successfully to target MYOC using adenovirus 5 (Ad5). However, Ad5 is not a suitable vector for clinical use. Here, we sought to determine the efficacy of adeno-associated viruses (AAVs) and lentiviruses (LVs) to target the TM. First, we examined the TM tropism of single-stranded (ss) and self-complimentary (sc) AAV serotypes as well as LV expressing GFP via intravitreal (IVT) and intracameral (IC) injections. We observed that LV_GFP expression was more specific to the TM injected via the IVT route. IC injections of Trp-mutant scAAV2 showed a prominent expression of GFP in the TM. However, robust GFP expression was also observed in the ciliary body and retina. We next constructed lentiviral particles expressing Cas9 and guide RNA (gRNA) targeting MYOC (crMYOC) and transduction of TM cells stably expressing mutant myocilin with LV_crMYOC significantly reduced myocilin accumulation and its associated chronic ER stress. A single IVT injection of LV_crMYOC in Tg-MYOCY437H mice decreased myocilin accumulation in TM and reduced elevated IOP significantly. Together, our data indicates, LV_crMYOC targets MYOC gene editing in TM and rescues a mouse model of myocilin-associated glaucoma.
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Affiliation(s)
- Shruti V Patil
- University of North Texas Health Science Center at Fort Worth
| | | | - Sujata Ranshing
- University of North Texas Health Science Center at Fort Worth
| | | | | | | | | | | | | | | | | | - Abbot F Clark
- University of North Texas Health Science Center at Fort Worth
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5
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Buffault J, Brignole-Baudouin F, Labbé A, Baudouin C. An Overview of Current Glaucomatous Trabecular Meshwork Models. Curr Eye Res 2023; 48:1089-1099. [PMID: 37661784 DOI: 10.1080/02713683.2023.2253378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 07/26/2023] [Accepted: 08/25/2023] [Indexed: 09/05/2023]
Abstract
PURPOSE To provide an overview of the existing alternative models for studying trabecular meshwork (TM). METHODS Literature review. RESULTS The TM is a complex tissue that regulates aqueous humor outflow from the eye. Dysfunction of the TM is a major contributor to the pathogenesis of open-angle glaucoma, a leading cause of irreversible blindness worldwide. The TM is a porous structure composed of trabecular meshwork cells (TMC) within a multi-layered extracellular matrix (ECM). Although dysregulation of the outflow throughout the TM represents the first step in the disease process, the underlying mechanisms of TM degeneration associate cell loss and accumulation of ECM, but remain incompletely understood, and drugs targeting the TM are limited. Therefore, experimental models of glaucomatous trabeculopathy are necessary for preclinical screening, to advance research on this disease's pathophysiology, and to develop new therapeutic strategies targeting the TM. Traditional animal models have been used extensively, albeit with inherent limitations, including ethical concerns and limited translatability to humans. Consequently, there has been an increasing focus on developing alternative in vitro models to study the TM. Recent advancements in three-dimensional cell culture and tissue engineering are still in their early stages and do not yet fully reflect the complexity of the outflow pathway. However, they have shown promise in reducing reliance on animal experimentation in certain aspects of glaucoma research. CONCLUSION This review provides an overview of the existing alternative models for studying TM and their potential for advancing research on the pathophysiology of open-angle glaucoma and developing new therapeutic strategies.
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Affiliation(s)
- Juliette Buffault
- Department of Ophthalmology III, Quinze-Vingts National Ophthalmology Hospital, IHU Foresight, Paris, France
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, IHU Foresight, Paris, France
- Department of Ophthalmology, Ambroise Paré Hospital, APHP, Université de Versailles Saint-Quentin-en-Yvelines, Boulogne-Billancourt, France
| | - Françoise Brignole-Baudouin
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, IHU Foresight, Paris, France
- Department of Biology, Quinze-Vingts National Ophthalmology Hospital, IHU Foresight, Paris, France
| | - Antoine Labbé
- Department of Ophthalmology III, Quinze-Vingts National Ophthalmology Hospital, IHU Foresight, Paris, France
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, IHU Foresight, Paris, France
- Department of Ophthalmology, Ambroise Paré Hospital, APHP, Université de Versailles Saint-Quentin-en-Yvelines, Boulogne-Billancourt, France
| | - Christophe Baudouin
- Department of Ophthalmology III, Quinze-Vingts National Ophthalmology Hospital, IHU Foresight, Paris, France
- Institut de la Vision, Sorbonne Université, INSERM, CNRS, IHU Foresight, Paris, France
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6
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Saccuzzo EG, Youngblood HA, Lieberman RL. Myocilin misfolding and glaucoma: A 20-year update. Prog Retin Eye Res 2023; 95:101188. [PMID: 37217093 PMCID: PMC10330797 DOI: 10.1016/j.preteyeres.2023.101188] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 05/24/2023]
Abstract
Mutations in the gene MYOC account for approximately 5% of cases of primary open angle glaucoma (POAG). MYOC encodes for the protein myocilin, a multimeric secreted glycoprotein composed of N-terminal coiled-coil (CC) and leucine zipper (LZ) domains that are connected via a disordered linker to a 30 kDa olfactomedin (OLF) domain. More than 90% of glaucoma-causing mutations are localized to the OLF domain. While myocilin is expressed in numerous tissues, mutant myocilin is only associated with disease in the anterior segment of the eye, in the trabecular meshwork. The prevailing pathogenic mechanism involves a gain of toxic function whereby mutant myocilin aggregates intracellularly instead of being secreted, which causes cell stress and an early timeline for TM cell death, elevated intraocular pressure, and subsequent glaucoma-associated retinal degeneration. In this review, we focus on the work our lab has conducted over the past ∼15 years to enhance our molecular understanding of myocilin-associated glaucoma, which includes details of the molecular structure and the nature of the aggregates formed by mutant myocilin. We conclude by discussing open questions, such as predicting phenotype from genotype alone, the elusive native function of myocilin, and translational directions enabled by our work.
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Affiliation(s)
- Emily G Saccuzzo
- School of Chemistry & Biochemistry, Georgia Institute of Technology, 901 Atlantic Dr. NW, Atlanta, GA, 30332-0400, USA
| | - Hannah A Youngblood
- School of Chemistry & Biochemistry, Georgia Institute of Technology, 901 Atlantic Dr. NW, Atlanta, GA, 30332-0400, USA
| | - Raquel L Lieberman
- School of Chemistry & Biochemistry, Georgia Institute of Technology, 901 Atlantic Dr. NW, Atlanta, GA, 30332-0400, USA.
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7
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Abstract
Viral transduction of the mouse trabecular meshwork using a variety of transgenes associated with glaucoma generates an inducible and reproducible method for generating ocular hypertension due to increased aqueous humor outflow resistance of the conventional outflow pathway. Both adenovirus serotype 5 (Ad5) and lentiviruses have selective tropism for the mouse trabecular meshwork with intraocular injections. Accurate intraocular pressures are easily measured using a rebound tonometer, and aqueous humor outflow facilities can be measured in anesthetized live mice.
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Affiliation(s)
- J Cameron Millar
- Department of Pharmacology & Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Yogapriya Sundaresan
- Department of Pharmacology & Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, USA
- Department of Ophthalmology, Gaven Herbert Eye Institute, UC Irvine, Irvine, CA, USA
| | - Gulab S Zode
- Department of Pharmacology & Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, USA
- Department of Ophthalmology, Gaven Herbert Eye Institute, UC Irvine, Irvine, CA, USA
| | - Abbot F Clark
- Department of Pharmacology & Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, USA.
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8
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Abstract
The trabecular meshwork (TM) of the eye serves as an essential tissue in controlling aqueous humor (AH) outflow and intraocular pressure (IOP) homeostasis. However, dysfunctional TM cells and/or decreased TM cellularity is become a critical pathogenic cause for primary open-angle glaucoma (POAG). Consequently, it is particularly valuable to investigate TM characteristics, which, in turn, facilitates the development of new treatments for POAG. Since 2006, the advancement in induced pluripotent stem cells (iPSCs) provides a new tool to (1) model the TM in vitro and (2) regenerate degenerative TM in POAG. In this context, we first summarize the current approaches to induce the differentiation of TM-like cells from iPSCs and compare iPSC-derived TM models to the conventional in vitro TM models. The efficacy of iPSC-derived TM cells for TM regeneration in POAG models is also discussed. Through these approaches, iPSCs are becoming essential tools in glaucoma modeling and for developing personalized treatments for TM regeneration.
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Affiliation(s)
- Wei Zhu
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, China.
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University & Capital Medical University, Beijing, China.
| | - Xiaoyan Zhang
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao, China
| | - Shen Wu
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Capital Medical University, Beijing, China
| | - Ningli Wang
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University & Capital Medical University, Beijing, China
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Capital Medical University, Beijing, China
| | - Markus H Kuehn
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
- Center for the Prevention and Treatment of Visual Loss, Iowa City Veterans Affairs Medical Center, Iowa City, IA, USA
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9
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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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10
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Intraocular Pressure-Induced Endothelial Dysfunction of Retinal Blood Vessels Is Persistent, but Does Not Trigger Retinal Ganglion Cell Loss. Antioxidants (Basel) 2022; 11:antiox11101864. [PMID: 36290587 PMCID: PMC9598728 DOI: 10.3390/antiox11101864] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 09/11/2022] [Accepted: 09/15/2022] [Indexed: 12/02/2022] Open
Abstract
Research has been conducted into vascular abnormalities in the pathogenesis of glaucoma, but conclusions remain controversial. Our aim was to test the hypothesis that retinal endothelial dysfunction induced by elevated intraocular pressure (IOP) persists after IOP normalization, further triggering retinal ganglion cell (RGC) loss. High intraocular pressure (HP) was induced in mice by episcleral vein occlusion (EVO). Retinal vascular function was measured via video microscopy in vitro. The IOP, RGC and their axons survival, levels of oxidative stress and inflammation as well as vascular pericytes coverage, were determined. EVO caused HP for two weeks, which returned to baseline afterwards. Mice with HP exhibited endothelial dysfunction in retinal arterioles, reduced density of RGC and their axons, and loss of pericytes in retinal arterioles. Notably, these values were similar to those of mice with recovered IOP (RP). Levels of oxidative stress and inflammation were increased in HP mice but went back to normal in the RP mice. Our data demonstrate that HP induces persistent endothelial dysfunction in retinal arterioles, which persists one month after RP. Oxidative stress, inflammation, and loss of pericytes appear to be involved in triggering vascular functional deficits. Our data also suggest that retinal endothelial dysfunction does not affect RGC and their axon survival.
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11
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Patil SV, Kasetti RB, Millar JC, Zode GS. A Novel Mouse Model of TGFβ2-Induced Ocular Hypertension Using Lentiviral Gene Delivery. Int J Mol Sci 2022; 23:6883. [PMID: 35805889 PMCID: PMC9266301 DOI: 10.3390/ijms23136883] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 06/13/2022] [Accepted: 06/17/2022] [Indexed: 01/27/2023] Open
Abstract
Glaucoma is a multifactorial disease leading to irreversible blindness. Primary open-angle glaucoma (POAG) is the most common form and is associated with the elevation of intraocular pressure (IOP). Reduced aqueous humor (AH) outflow due to trabecular meshwork (TM) dysfunction is responsible for IOP elevation in POAG. Extracellular matrix (ECM) accumulation, actin cytoskeletal reorganization, and stiffening of the TM are associated with increased outflow resistance. Transforming growth factor (TGF) β2, a profibrotic cytokine, is known to play an important role in the development of ocular hypertension (OHT) in POAG. An appropriate mouse model is critical in understanding the underlying molecular mechanism of TGFβ2-induced OHT. To achieve this, TM can be targeted with recombinant viral vectors to express a gene of interest. Lentiviruses (LV) are known for their tropism towards TM with stable transgene expression and low immunogenicity. We, therefore, developed a novel mouse model of IOP elevation using LV gene transfer of active human TGFβ2 in the TM. We developed an LV vector-encoding active hTGFβ2C226,228S under the control of a cytomegalovirus (CMV) promoter. Adult C57BL/6J mice were injected intravitreally with LV expressing null or hTGFβ2C226,228S. We observed a significant increase in IOP 3 weeks post-injection compared to control eyes with an average delta change of 3.3 mmHg. IOP stayed elevated up to 7 weeks post-injection, which correlated with a significant drop in the AH outflow facility (40.36%). Increased expression of active TGFβ2 was observed in both AH and anterior segment samples of injected mice. The morphological assessment of the mouse TM region via hematoxylin and eosin (H&E) staining and direct ophthalmoscopy examination revealed no visible signs of inflammation or other ocular abnormalities in the injected eyes. Furthermore, transduction of primary human TM cells with LV_hTGFβ2C226,228S exhibited alterations in actin cytoskeleton structures, including the formation of F-actin stress fibers and crossed-linked actin networks (CLANs), which are signature arrangements of actin cytoskeleton observed in the stiffer fibrotic-like TM. Our study demonstrated a mouse model of sustained IOP elevation via lentiviral gene delivery of active hTGFβ2C226,228S that induces TM dysfunction and outflow resistance.
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Affiliation(s)
| | | | | | - Gulab S. Zode
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX 76107, USA; (S.V.P.); (R.B.K.); (J.C.M.)
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12
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Mavlyutov TA, Myrah JJ, Chauhan AK, Liu Y, McDowell CM. Fibronectin extra domain A (FN-EDA) causes glaucomatous trabecular meshwork, retina, and optic nerve damage in mice. Cell Biosci 2022; 12:72. [PMID: 35619185 PMCID: PMC9137085 DOI: 10.1186/s13578-022-00800-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 04/27/2022] [Indexed: 12/15/2022] Open
Abstract
Background Elevated intraocular pressure (IOP) is a major risk factor for the development and progression of primary open angle glaucoma and is due to trabecular meshwork (TM) damage. Here, we investigate the role of an endogenous Toll-like receptor 4 (TLR4) ligand, FN-EDA, in the development of glaucoma utilizing a transgenic mouse strain (B6.EDA+/+) that constitutively expresses only FN containing the EDA isoform. Methods Eyes from C57BL6/J (wild-type), B6.EDA+/+ (constitutively active EDA), B6.EDA-/- (EDA null) mice were processed for electron microscopy and consecutive images of the entire length of the TM and Schlemm’s canal (SC) from anterior to posterior were collected and montaged into a single image. ECM accumulation, basement membrane length, and size and number of giant vacuoles were quantified by ImageJ analysis. Tlr4 and Iba1 expression in the TM and ONH cells was conducted using RNAscope in situ hybridization and immunohistochemistry protocols. IOP was measured using a rebound tonometer, ON damage assessed by PPD stain, and RGC loss quantified in RBPMS labeled retina flat mounts. Results Ultrastructure analyses show the TM of B6.EDA+/+ mice have significantly increased accumulation of ECM between TM beams with few empty spaces compared to C57BL/6 J mice (p < 0.05). SC basement membrane is thicker and more continuous in B6.EDA+/+ mice compared to C57BL/6 J. No significant structural differences are detected in the TM of EDA null mice. Tlr4 and Iba1 expression is increased in the TM of B6.EDA+/+ mice compared to C57BL/6 J eyes (p < 0.05). IOP is significantly higher in B6.EDA+/+ mice compared to C57BL/6 J eyes (p < 0.001), and significant ON damage (p < 0.001) and RGC loss (p < 0.05) detected at 1 year of age. Tlr4 mRNA is expressed in mouse ONH cells, and is present in ganglion cell axons, microglia, and astrocytes. There is a significant increase in the area occupied by Iba-1 positive microglia cells in the ONH of B6.EDA+/+ mice compared to C57BL/6 J control eyes (p < 0.01). Conclusions B6.EDA+/+ mice have increased ECM accumulation in the TM, elevated IOP, enhanced proinflammatory changes in the ONH, loss of RGCs, and ONH damage. These data suggest B6.EDA+/+ mice recapitulate many aspects of glaucomatous damage. Supplementary Information The online version contains supplementary material available at 10.1186/s13578-022-00800-y.
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Affiliation(s)
- Timur A Mavlyutov
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Justin J Myrah
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA
| | - Anil K Chauhan
- Department of Internal Medicine, Division of Hematology/Oncology, University of Iowa, Iowa City, IA, USA
| | - Yang Liu
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Colleen M McDowell
- Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, USA.
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13
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Yan X, Wu S, Liu Q, Cheng Y, Zhang J, Wang N. Myocilin Gene Mutation Induced Autophagy Activation Causes Dysfunction of Trabecular Meshwork Cells. Front Cell Dev Biol 2022; 10:900777. [PMID: 35615698 PMCID: PMC9124892 DOI: 10.3389/fcell.2022.900777] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 04/08/2022] [Indexed: 12/12/2022] Open
Abstract
Trabecular meshwork dysfunction is the main cause of primary open angle glaucoma (POAG) associated with elevated intraocular pressure (IOP). Mutant myocilin causes glaucoma mainly via elevating IOP. Previously we have found that accumulated Asn 450 Tyr (N450Y) mutant myocilin impairs human trabecular meshwork (TM) cells by inducing chronic endoplasmic reticulum (ER) stress response in vitro. However, it is unclear how ER stress leads to TM damage and whether N450Y myocilin mutation is associated with POAG in vivo. Here we found that N450Y mutant myocilin induces autophagy, which worsens cell viability, whereas inhibition of autophagy increases viability and decreases cell death in human TM cells. Furthermore, we construct a transgenic mouse model of N450Y myocilin mutation (Tg-MYOCN450Y) and Tg-MYOCN450Y mice exhibiting glaucoma phenotypes: IOP elevation, retinal ganglion cell loss and visual impairment. Consistent with our published in vitro studies, mutant myocilin fails to secrete into aqueous humor, causes ER stress and actives autophagy in Tg-MYOCN450Y mice, and aqueous humor dynamics are altered in Tg-MYOCN450Y mice. In summary, our studies demonstrate that activation of autophagy is correlated with pathogenesis of POAG.
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Affiliation(s)
- Xuejing Yan
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
- Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Shen Wu
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
- Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Qian Liu
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
- Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
| | - Ying Cheng
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
| | - Jingxue Zhang
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
- Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
- *Correspondence: Ningli Wang, ; Jingxue Zhang,
| | - Ningli Wang
- Beijing Tongren Eye Center, Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Hospital, Beijing Institute of Ophthalmology, Capital Medical University, Beijing, China
- Collaborative Innovation Center for Brain Disorders, Beijing Institute of Brain Disorders, Capital Medical University, Beijing, China
- *Correspondence: Ningli Wang, ; Jingxue Zhang,
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14
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Sugali CK, Rayana NP, Dai J, Peng M, Mao W. Age and sex affect TGFβ2-induced ocular hypertension in C57BL/6J mice. Exp Eye Res 2022; 219:109055. [DOI: 10.1016/j.exer.2022.109055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2021] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 11/24/2022]
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15
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Systemic Treatment with Pioglitazone Reverses Vision Loss in Preclinical Glaucoma Models. Biomolecules 2022; 12:biom12020281. [PMID: 35204782 PMCID: PMC8961625 DOI: 10.3390/biom12020281] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/03/2022] [Accepted: 02/08/2022] [Indexed: 02/04/2023] Open
Abstract
Neuroinflammation significantly contributes to the pathophysiology of several neurodegenerative diseases. This is also the case in glaucoma and may be a reason why many patients suffer from progressive vision loss despite maximal reduction in intraocular pressure. Pioglitazone is an agonist of the peroxisome proliferator-activated receptor gamma (PPARγ) whose pleiotrophic activities include modulation of cellular energy metabolism and reduction in inflammation. In this study we employed the DBA2/J mouse model of glaucoma with chronically elevated intraocular pressure to investigate whether oral low-dose pioglitazone treatment preserves retinal ganglion cell (RGC) survival. We then used an inducible glaucoma model in C57BL/6J mice to determine visual function, pattern electroretinographs, and tracking of optokinetic reflex. Our findings demonstrate that pioglitazone treatment does significantly protect RGCs and prevents axonal degeneration in the glaucomatous retina. Furthermore, treatment preserves and partially reverses vision loss in spite of continuously elevated intraocular pressure. These data suggest that pioglitazone may provide treatment benefits for those glaucoma patients experiencing continued vision loss.
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16
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McDowell CM, Kizhatil K, Elliott MH, Overby DR, van Batenburg-Sherwood J, Millar JC, Kuehn MH, Zode G, Acott TS, Anderson MG, Bhattacharya SK, Bertrand JA, Borras T, Bovenkamp DE, Cheng L, Danias J, De Ieso ML, Du Y, Faralli JA, Fuchshofer R, Ganapathy PS, Gong H, Herberg S, Hernandez H, Humphries P, John SWM, Kaufman PL, Keller KE, Kelley MJ, Kelly RA, Krizaj D, Kumar A, Leonard BC, Lieberman RL, Liton P, Liu Y, Liu KC, Lopez NN, Mao W, Mavlyutov T, McDonnell F, McLellan GJ, Mzyk P, Nartey A, Pasquale LR, Patel GC, Pattabiraman PP, Peters DM, Raghunathan V, Rao PV, Rayana N, Raychaudhuri U, Reina-Torres E, Ren R, Rhee D, Chowdhury UR, Samples JR, Samples EG, Sharif N, Schuman JS, Sheffield VC, Stevenson CH, Soundararajan A, Subramanian P, Sugali CK, Sun Y, Toris CB, Torrejon KY, Vahabikashi A, Vranka JA, Wang T, Willoughby CE, Xin C, Yun H, Zhang HF, Fautsch MP, Tamm ER, Clark AF, Ethier CR, Stamer WD. Consensus Recommendation for Mouse Models of Ocular Hypertension to Study Aqueous Humor Outflow and Its Mechanisms. Invest Ophthalmol Vis Sci 2022; 63:12. [PMID: 35129590 PMCID: PMC8842499 DOI: 10.1167/iovs.63.2.12] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 12/08/2021] [Indexed: 01/07/2023] Open
Abstract
Due to their similarities in anatomy, physiology, and pharmacology to humans, mice are a valuable model system to study the generation and mechanisms modulating conventional outflow resistance and thus intraocular pressure. In addition, mouse models are critical for understanding the complex nature of conventional outflow homeostasis and dysfunction that results in ocular hypertension. In this review, we describe a set of minimum acceptable standards for developing, characterizing, and utilizing mouse models of open-angle ocular hypertension. We expect that this set of standard practices will increase scientific rigor when using mouse models and will better enable researchers to replicate and build upon previous findings.
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Affiliation(s)
- Colleen M. McDowell
- Department of Ophthalmology and Visual Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | | | - Michael H. Elliott
- University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States
| | - Darryl R. Overby
- Department of Bioengineering, Imperial College London, United Kingdom
| | | | - J. Cameron Millar
- Department of Pharmacology & Neuroscience, and North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Markus H. Kuehn
- Department of Ophthalmology and Visual Sciences and Institute for Vision Research, The University of Iowa; Center for the Prevention and Treatment of Visual Loss, Veterans Affairs Medical Center, Iowa City, Iowa, United States
| | - Gulab Zode
- Department of Pharmacology & Neuroscience, and North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Ted S. Acott
- Ophthalmology and Biochemistry and Molecular Biology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Michael G. Anderson
- Department of Molecular Physiology and Biophysics and Department of Ophthalmology and Visual Sciences, The University of Iowa; Center for the Prevention and Treatment of Visual Loss, Veterans Affairs Medical Center, Iowa City, Iowa, United States
| | | | - Jacques A. Bertrand
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Terete Borras
- University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States
| | | | - Lin Cheng
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, United States
| | - John Danias
- SUNY Downstate Health Sciences University, Brooklyn, New York, United States
| | - Michael Lucio De Ieso
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, North Carolina, United States
| | - Yiqin Du
- Department of Ophthalmology, University of Pittsburgh, Pennsylvania, United States
| | - Jennifer A. Faralli
- Department of Pathology and Laboratory Medicine, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Rudolf Fuchshofer
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Preethi S. Ganapathy
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Samuel Herberg
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
| | | | - Peter Humphries
- Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - Simon W. M. John
- Department of Ophthalmology, Columbia University, New York, New York, United States
| | - Paul L. Kaufman
- Department of Ophthalmology and Visual Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Kate E. Keller
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Mary J. Kelley
- Department of Ophthalmology and Department of Integrative Biosciences, Oregon Health & Science University, Portland, Oregon, United States
| | - Ruth A. Kelly
- Ocular Genetics Unit, Smurfit Institute of Genetics, Trinity College Dublin, Dublin, Ireland
| | - David Krizaj
- Department of Ophthalmology, University of Utah School of Medicine, Salt Lake City, Utah, United States
| | - Ajay Kumar
- Department of Ophthalmology, University of Pittsburgh, Pennsylvania, United States
| | - Brian C. Leonard
- Department of Surgical and Radiological Sciences, University of California, Davis, Davis, California, United States
| | - Raquel L. Lieberman
- Department of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, United States
| | - Paloma Liton
- Department of Ophthalmology and Department of Pathology, Duke University, Durham, North Carolina, United States
| | - Yutao Liu
- Department of Cellular Biology and Anatomy, James & Jean Culver Vision Discovery Institute, Augusta University, Augusta, Georgia, United States
| | - Katy C. Liu
- Duke Eye Center, Duke Health, Durham, North Carolina, United States
| | - Navita N. Lopez
- Department of Neurobiology, University of Utah, Salt Lake City, Utah, United States
| | - Weiming Mao
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Timur Mavlyutov
- Department of Ophthalmology and Visual Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Fiona McDonnell
- Duke Eye Center, Duke Health, Durham, North Carolina, United States
| | - Gillian J. McLellan
- Department of Surgical Sciences and Department of Ophthalmology and Visual Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Philip Mzyk
- Department of Ophthalmology and Visual Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | - Andrews Nartey
- College of Optometry, University of Houston, Houston, Texas, United States
| | - Louis R. Pasquale
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York, United States
| | - Gaurang C. Patel
- Ophthalmology Research, Regeneron Pharmaceuticals, Tarreytown, New York, United States
| | | | - Donna M. Peters
- Department of Pathology and Laboratory Medicine, University of Wisconsin–Madison, Madison, Wisconsin, United States
| | | | - Ponugoti Vasantha Rao
- Department of Ophthalmology, Duke University School of Medicine, Durham, North Carolina, United States
| | - Naga Rayana
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Urmimala Raychaudhuri
- Department of Neurobiology, University of California, Irvine, Irvine, California, United States
| | - Ester Reina-Torres
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Ruiyi Ren
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Douglas Rhee
- Case Western Reserve University School of Medicine, Cleveland, Ohio, United States
| | - Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - John R. Samples
- Washington State University, Floyd Elson College of Medicine, Spokane, Washington, United States
| | | | - Najam Sharif
- Santen Inc., Emeryville, California, United States
| | - Joel S. Schuman
- Department of Ophthalmology and Department of Physiology and Neuroscience, NYU Grossman School of Medicine, NYU Langone Health, New York University, New York, New York, United States; Departments of Biomedical Engineering and Electrical and Computer Engineering, New York University Tandon School of Engineering, Brooklyn, New York, United States; Center for Neural Science, College of Arts and Science, New York University, New York, New York, United States
| | - Val C. Sheffield
- Department of Pediatrics and Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States
| | - Cooper H. Stevenson
- Department of Pharmacology & Neuroscience, and North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Avinash Soundararajan
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | | | - Chenna Kesavulu Sugali
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Yang Sun
- Veterans Affairs Palo Alto Health Care System, Stanford University, Palo Alto, California, United States
| | - Carol B. Toris
- Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, Nebraska, United States; Department of Ophthalmology and Vision Sciences, The Ohio State University, Columbus, Ohio, United States
| | | | - Amir Vahabikashi
- Cell and Developmental Biology Department, Northwestern University, Chicago, Illinois, United States
| | - Janice A. Vranka
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Ting Wang
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Colin E. Willoughby
- Genomic Medicine, Biomedical Sciences Research Institute, Ulster University, Coleraine, Northern Ireland, United Kingdom
| | - Chen Xin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Hongmin Yun
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States
| | - Hao F. Zhang
- Biomedical Engineering Department, Northwestern University, Evanston, Illinois, United States
| | - Michael P. Fautsch
- Biomedical Engineering Department, Northwestern University, Evanston, Illinois, United States
| | | | - Abbot F. Clark
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - C. Ross Ethier
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology; Emory University School of Medicine, Emory University, Atlanta, Georgia, United States
| | - W. Daniel Stamer
- Duke Ophthalmology, Duke University, Durham, North Carolina, United States
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17
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Gao S, Huang X, Zhang Y, Bao L, Wang X, Zhang M. Investigation on the expression regulation of RIPK1/RIPK3 in the retinal ganglion cells (RGCs) cultured in high glucose. Bioengineered 2021; 12:3947-3956. [PMID: 34281454 PMCID: PMC8806785 DOI: 10.1080/21655979.2021.1944456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 06/12/2021] [Indexed: 02/08/2023] Open
Abstract
Diabetic retinopathy (DR) represents the most typical complication of type 2 diabetes mellitus and one of the most primary oculopathy causing blindness. However, the mechanism of DR remains unknown. RIPK1/RIPK3, as homologous serine/threonine kinases, are key elements in mediating necroptosis and may have functions in DR development. To clarify the relationship between DR and RIPK1/RIPK3, this study established a model of apoptosis using high-glucose induced RGCs, which were treated with 7.5, 19.5, and 35 mM D-glucose for 12, 24, and 48 h, respectively. Subsequently, the expression of RIPK1/RIPK3 was determined and the protective effect of necrostatin-1 on RGCs injury induced by high glucose was explored. The results demonstrated that the expression of RIPK1 and RIPK3 in the cells was increased markedly following 12 h treatment with 19.5 mM D-glucose. Additionally, following an addition of 100 μM necrostatin-1 in 19.5 mM D-glucose medium for RGCs treatment 12 h, the protein expression of RIPK1 and RIPK3 was decreased markedly, and the number of Nissl bodies in cells was increased substantially. The findings of the present study indicated that high glucose could induce the expression of RIPK1/RIPK3, and necrostatin-1 could effectively protect RGCs from D-glucose-induced cell necrosis.
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Affiliation(s)
- Sheng Gao
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Xi Huang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Yi Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
| | - Li Bao
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Xiaoyue Wang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Meixia Zhang
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
- Research Laboratory of Macular Disease, West China Hospital, Sichuan University, Chengdu, China
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18
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Sharma R, Grover A. Myocilin-associated Glaucoma: A Historical Perspective and Recent Research Progress. Mol Vis 2021; 27:480-493. [PMID: 34497454 PMCID: PMC8403517] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 08/18/2021] [Indexed: 10/29/2022] Open
Abstract
Glaucoma a debilitating disease, is globally the second most common kind of permanent blindness. Primary open-angle glaucoma (POAG) is its most prevalent form and is often linked with alterations in the myocilin gene (MYOC). MYOC encodes the myocilin protein, which is expressed throughout the body, but primarily in trabecular meshwork (TM) tissue in the eyes. TM is principally involved in regulating intraocular pressure (IOP), and elevated IOP is the main risk factor associated with glaucoma. The myocilin protein's function remains unknown; however, mutations compromise its folding and processing inside TM cells, contributing to the glaucoma phenotype. While glaucoma is a complex disease with various molecules and factors as contributing causes, the role played by myocilin has been the most widely studied. The current review describes the present understanding of myocilin and its association with glaucoma and aims to shift the focus toward developing targeted therapies for treating glaucoma patients with variations in MYOC.
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Early Functional Impairment in Experimental Glaucoma Is Accompanied by Disruption of the GABAergic System and Inceptive Neuroinflammation. Int J Mol Sci 2021; 22:ijms22147581. [PMID: 34299211 PMCID: PMC8306430 DOI: 10.3390/ijms22147581] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 07/09/2021] [Accepted: 07/13/2021] [Indexed: 12/21/2022] Open
Abstract
Glaucoma is a leading cause of irreversible blindness worldwide, and increased intraocular pressure (IOP) is a major risk factor. We aimed to determine if early functional and molecular differences in the glaucomatous retina manifest before significant retinal ganglion cell (RGC) loss is apparent. Adenoviral vectors expressing a pathogenic form of myocilin (Ad5.MYOC) were used to induce IOP elevation in C57BL/6 mice. IOP and pattern electroretinograms (pERG) were recorded, and retinas were prepared for RNA sequencing, immunohistochemistry, or to determine RGC loss. Ocular injection of Ad5.MYOC leads to reliable IOP elevation, resulting in significant loss of RGC after nine weeks. A significant decrease in the pERG amplitude was evident in eyes three weeks after IOP elevation. Retinal gene expression analysis revealed increased expression for 291 genes related to complement cascade, inflammation, and antigen presentation in hypertensive eyes. Decreased expression was found for 378 genes associated with the γ-aminobutyric acid (GABA)ergic and glutamatergic systems and axon guidance. These data suggest that early functional changes in RGC might be due to reduced GABAA receptor signaling and neuroinflammation that precedes RGC loss in this glaucoma model. These initial changes may offer new targets for early detection of glaucoma and the development of new interventions.
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Scelsi HF, Barlow BM, Saccuzzo EG, Lieberman RL. Common and rare myocilin variants: Predicting glaucoma pathogenicity based on genetics, clinical, and laboratory misfolding data. Hum Mutat 2021; 42:903-946. [PMID: 34082484 DOI: 10.1002/humu.24238] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 05/07/2021] [Accepted: 05/31/2021] [Indexed: 12/12/2022]
Abstract
Rare variants of the olfactomedin domain of myocilin are considered causative for inherited, early-onset open-angle glaucoma, with a misfolding toxic gain-of-function pathogenic mechanism detailed by 20 years of laboratory research. Myocilin variants are documented in the scientific literature and identified through large-scale genetic sequencing projects such as those curated in the Genome Aggregation Database (gnomAD). In the absence of key clinical and laboratory information, however, the pathogenicity of any given variant is not clear, because glaucoma is a heterogeneous and prevalent age-onset disease, and common variants are likely benign. In this review, we reevaluate the likelihood of pathogenicity for the ~100 nonsynonymous missense, insertion-deletion, and premature termination of myocilin olfactomedin variants documented in the literature. We integrate available clinical, laboratory cellular, biochemical and biophysical data, the olfactomedin domain structure, and population genetics data from gnomAD. Of the variants inspected, ~50% can be binned based on a preponderance of data, leaving many of uncertain pathogenicity that motivate additional studies. Ultimately, the approach of combining metrics from different disciplines will likely resolve outstanding complexities regarding the role of this misfolding-prone protein within the context of a multifactorial and prevalent ocular disease, and pave the way for new precision medicine therapeutics.
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Affiliation(s)
- Hailee F Scelsi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Brett M Barlow
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Emily G Saccuzzo
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Raquel L Lieberman
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA
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21
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Gramlich OW, Godwin CR, Heuss ND, Gregerson DS, Kuehn MH. T and B Lymphocyte Deficiency in Rag1-/- Mice Reduces Retinal Ganglion Cell Loss in Experimental Glaucoma. Invest Ophthalmol Vis Sci 2021; 61:18. [PMID: 33320171 PMCID: PMC7745626 DOI: 10.1167/iovs.61.14.18] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose We previously demonstrated that passive transfer of lymphocytes from glaucomatous mice induces retinal ganglion cell (RGC) damage in recipient animals, suggesting a role for immune responses in the multifactorial pathophysiology of glaucoma. Here we evaluate whether absence of an adaptive immune response reduces RGC loss in glaucoma. Methods Elevated intraocular pressure (IOP) was induced in one eye of C57BL/6J (B6) or T- and B-cell–deficient Rag1−/− knockout mice. After 16 weeks RGC density was determined in both the induced and the normotensive contralateral eyes. Data were compared to mice having received injections of “empty” vector (controls). The number of extravascular CD3+ cells in the retinas was determined using FACS. Results Retinas of eyes with elevated IOP contain significantly more extravasated CD3+ cells than control retinas (46.0 vs. 27.1, P = 0.025). After 16 weeks of elevated IOP the average RGC density in B6 mice decreased by 20.7% (P = 1.9 × 10−4). In contrast, RGC loss in Rag1−/− eyes with elevated IOP was significantly lower (10.3%, P = 0.006 vs. B6). RGC loss was also observed in the contralateral eyes of B6 mice, despite the absence of elevated IOP in those eyes (10.1%; P = 0.008). In RAG1−/− loss in the contralateral eyes was minimal (3.1%) and significantly below that detected in B6 (P = 0.02). Conclusions Our findings demonstrate that T Rag1−/− mice are significantly protected from glaucomatous RGC loss. In this model, lymphocyte activity contributes to approximately half of all RGC loss in eyes with elevated IOP and to essentially all loss observed in normotensive contralateral eyes.
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Affiliation(s)
- Oliver W Gramlich
- University of Iowa, Department of Ophthalmology and Visual Sciences, Iowa City, Iowa, United States.,Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, Iowa, United States
| | - Cheyanne R Godwin
- University of Iowa, Department of Ophthalmology and Visual Sciences, Iowa City, Iowa, United States.,Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, Iowa, United States
| | - Neal D Heuss
- University of Minnesota, Department of Ophthalmology and Visual Neurosciences, Minneapolis, Minnesota, United States
| | - Dale S Gregerson
- University of Minnesota, Department of Ophthalmology and Visual Neurosciences, Minneapolis, Minnesota, United States
| | - Markus H Kuehn
- University of Iowa, Department of Ophthalmology and Visual Sciences, Iowa City, Iowa, United States.,Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, Iowa City, Iowa, United States
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22
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Kasetti RB, Maddineni P, Kiehlbauch C, Patil S, Searby CC, Levine B, Sheffield VC, Zode GS. Autophagy stimulation reduces ocular hypertension in a murine glaucoma model via autophagic degradation of mutant myocilin. JCI Insight 2021; 6:143359. [PMID: 33539326 PMCID: PMC8021112 DOI: 10.1172/jci.insight.143359] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 01/28/2021] [Indexed: 02/06/2023] Open
Abstract
Elevation of intraocular pressure (IOP) due to trabecular meshwork (TM) damage is associated with primary open-angle glaucoma (POAG). Myocilin mutations resulting in elevated IOP are the most common genetic causes of POAG. We have previously shown that mutant myocilin accumulates in the ER and induces chronic ER stress, leading to TM damage and IOP elevation. However, it is not understood how chronic ER stress leads to TM dysfunction and loss. Here, we report that mutant myocilin activated autophagy but was functionally impaired in cultured human TM cells and in a mouse model of myocilin-associated POAG (Tg-MYOCY437H). Genetic and pharmacological inhibition of autophagy worsened mutant myocilin accumulation and exacerbated IOP elevation in Tg-MYOCY437H mice. Remarkably, impaired autophagy was associated with chronic ER stress-induced transcriptional factor CHOP. Deletion of CHOP corrected impaired autophagy, enhanced recognition and degradation of mutant myocilin by autophagy, and reduced glaucoma in Tg-MYOCY437H mice. Stimulating autophagic flux via tat-beclin 1 peptide or torin 2 promoted autophagic degradation of mutant myocilin and reduced elevated IOP in Tg-MYOCY437H mice. Our study provides an alternate treatment strategy for myocilin-associated POAG by correcting impaired autophagy in the TM.
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Affiliation(s)
- Ramesh B. Kasetti
- Department of Pharmacology and Neuroscience and the North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
| | - Prabhavathi Maddineni
- Department of Pharmacology and Neuroscience and the North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
| | - Charles Kiehlbauch
- Department of Pharmacology and Neuroscience and the North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
| | - Shruti Patil
- Department of Pharmacology and Neuroscience and the North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
| | - Charles C. Searby
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Beth Levine
- Center for Autophagy Research, Department of Internal Medicine
- Howard Hughes Medical Institute, and
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Val C. Sheffield
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Gulab S. Zode
- Department of Pharmacology and Neuroscience and the North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, Texas, USA
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23
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Pang IH, Clark AF. Inducible rodent models of glaucoma. Prog Retin Eye Res 2020; 75:100799. [PMID: 31557521 PMCID: PMC7085984 DOI: 10.1016/j.preteyeres.2019.100799] [Citation(s) in RCA: 81] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Revised: 09/16/2019] [Accepted: 09/18/2019] [Indexed: 11/23/2022]
Abstract
Glaucoma is one of the leading causes of vision impairment worldwide. In order to further understand the molecular pathobiology of this disease and to develop better therapies, clinically relevant animal models are necessary. In recent years, both the rat and mouse have become popular models in glaucoma research. Key reasons are: many important biological similarities shared among rodent eyes and the human eye; development of improved methods to induce glaucoma and to evaluate glaucomatous damage; availability of genetic tools in the mouse; as well as the relatively low cost of rodent studies. Commonly studied rat and mouse glaucoma models include intraocular pressure (IOP)-dependent and pressure-independent models. The pressure-dependent models address the most important risk factor of elevated IOP, whereas the pressure-independent models assess "normal tension" glaucoma and other "non-IOP" related factors associated with glaucomatous damage. The current article provides descriptions of these models, their characterizations, specific techniques to induce glaucoma, mechanisms of injury, advantages, and limitations.
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Affiliation(s)
- Iok-Hou Pang
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, Fort Worth, Texas, USA
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, USA; Department of Pharmacology & Neuroscience, University of North Texas Health Science Center, Fort Worth, Texas, USA.
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24
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Yemanyi F, Vranka J, Raghunathan V. Generating cell-derived matrices from human trabecular meshwork cell cultures for mechanistic studies. Methods Cell Biol 2020; 156:271-307. [PMID: 32222223 DOI: 10.1016/bs.mcb.2019.10.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Ocular hypertension has been attributed to increased resistance to aqueous outflow often as a result of changes in trabecular meshwork (TM) extracellular matrix (ECM) using in vivo animal models (for example, by genetic manipulation) and ex vivo anterior segment perfusion organ cultures. These are, however, complex and difficult in dissecting molecular mechanisms and interactions. In vitro approaches to mimic the underlying substrate exist by manipulating either ECM topography, mechanics, or chemistry. These models best investigate the role of individual ECM protein(s) and/or substrate property, and thus do not recapitulate the multifactorial extracellular microenvironment; hence, mitigating its physiological relevance for mechanistic studies. Cell-derived matrices (CDMs), however, are capable of presenting a 3D-microenvironment rich in topography, chemistry, and whose mechanics can be tuned to better represent the network of native ECM constituents in vivo. Critically, the composition of CDMs may also be fine-tuned by addition of small molecules or relevant bioactive factors to mimic homeostasis or pathology. Here, we first provide a streamlined protocol for generating CDMs from TM cell cultures from normal or glaucomatous donor tissues. Second, we document how TM cells can be pharmacologically manipulated to obtain glucocorticoid-induced CDMs and how generated pristine CDMs can be manipulated with reagents like genipin. Finally, we summarize how CDMs may be used in mechanistic studies and discuss their probable application in future TM regenerative studies.
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Affiliation(s)
- Felix Yemanyi
- Department of Basic Sciences, University of Houston, Houston, TX, United States
| | - Janice Vranka
- Casey Eye Institute, Oregon Health and Science University, Portland, OR, United States
| | - VijayKrishna Raghunathan
- Department of Basic Sciences, University of Houston, Houston, TX, United States; The Ocular Surface Institute, College of Optometry, University of Houston, Houston, TX, United States; Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, TX, United States.
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25
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Hill SE, Kwon MS, Martin MD, Suntharalingam A, Hazel A, Dickey CA, Gumbart JC, Lieberman RL. Stable calcium-free myocilin olfactomedin domain variants reveal challenges in differentiating between benign and glaucoma-causing mutations. J Biol Chem 2019; 294:12717-12728. [PMID: 31270212 PMCID: PMC6709634 DOI: 10.1074/jbc.ra119.009419] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 06/25/2019] [Indexed: 01/07/2023] Open
Abstract
Nonsynonymous gene mutations can be beneficial, neutral, or detrimental to the stability, structure, and biological function of the encoded protein, but the effects of these mutations are often not readily predictable. For example, the β-propeller olfactomedin domain of myocilin (mOLF) exhibits a complex interrelationship among structure(s), stability, and aggregation. Numerous mutations within mOLF are linked to glaucoma; the resulting variants are less stable, aggregation-prone, and sequestered intracellularly, causing cytotoxicity. Here, we report the first stable mOLF variants carrying substitutions in the calcium-binding site that exhibit solution characteristics indistinguishable from those of glaucoma variants. Crystal structures of these stable variants at 1.8-2.0-Å resolution revealed features that we could not predict by molecular dynamics simulations, including loss of loop structure, helix unwinding, and a blade shift. Double mutants that combined a stabilizing substitution and a selected glaucoma-causing single-point mutant rescued in vitro folding and stability defects. In the context of full-length myocilin, secretion of stable single variants was indistinguishable from that of the WT protein, and the double mutants were secreted to varying extents. In summary, our finding that mOLF can tolerate particular substitutions that render the protein stable despite a conformational switch emphasizes the complexities in differentiating between benign and glaucoma-causing variants and provides new insight into the possible biological function of myocilin.
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Affiliation(s)
- Shannon E. Hill
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Michelle S. Kwon
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Mackenzie D. Martin
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Amirthaa Suntharalingam
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, University of South Florida, Tampa, Florida 33613
| | - Anthony Hazel
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Chad A. Dickey
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, University of South Florida, Tampa, Florida 33613
| | - James C. Gumbart
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332,School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332
| | - Raquel L. Lieberman
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia 30332, To whom correspondence should be addressed:
School of Chemistry and Biochemistry, Georgia Institute of Technology, 901 Atlantic Dr. NW, Atlanta, GA 30332-0400. E-mail:
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26
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Effect of ocular hypertension on the pattern of retinal ganglion cell subtype loss in a mouse model of early-onset glaucoma. Exp Eye Res 2019; 185:107703. [PMID: 31211954 PMCID: PMC7430001 DOI: 10.1016/j.exer.2019.107703] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 06/06/2019] [Accepted: 06/15/2019] [Indexed: 12/16/2022]
Abstract
Glaucoma is a neurodegenerative disease with elevated intraocular pressure as one of the major risk factors. Glaucoma leads to irreversible loss of vision and its progression involves optic nerve head cupping, axonal degeneration, retinal ganglion cell (RGC) loss, and visual field defects. Despite its high global prevalence, glaucoma still remains a major neurodegenerative disease. Introduction of mouse models of experimental glaucoma has become integral to glaucoma research due to well-studied genetics as well as ease of manipulations. Many established inherent and inducible mouse models of glaucoma are used to study the molecular and physiological progression of the disease. One such model of spontaneous mutation is the nee model, which is caused by mutation of the Sh3pxd2b gene. In both humans and mice, mutations disrupting function of the SH3PXD2B adaptor protein cause a developmental syndrome including secondary congenital glaucoma. The purpose of this study was to characterize the early onset nee glaucoma phenotype on the C57BL/6J background and to evaluate the pattern of RGC loss and axonal degeneration in specific RGC subtypes. We found that the B6.Sh3pxd2bnee mutant animals exhibit glaucoma phenotypes of elevated intraocular pressure, RGC loss and axonal degeneration. Moreover, the non-image forming RGCs survived longer than the On-Off direction selective RGCs (DSGC), and the axonal death in these RGCs was independent of their respective RGC subtype. In conclusion, through this study we characterized an experimental model of early onset glaucoma on a C57BL/6J background exhibiting key glaucoma phenotypes. In addition, we describe that RGC death has subtype-specific sensitivities and follows a specific pattern of cell death under glaucomatous conditions.
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27
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Patterson-Orazem AC, Hill SE, Wang Y, Dominic IM, Hall CK, Lieberman RL. Differential Misfolding Properties of Glaucoma-Associated Olfactomedin Domains from Humans and Mice. Biochemistry 2019; 58:1718-1727. [PMID: 30802039 DOI: 10.1021/acs.biochem.8b01309] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Mutations in myocilin, predominantly within its olfactomedin (OLF) domain, are causative for the heritable form of open angle glaucoma in humans. Surprisingly, mice expressing Tyr423His mutant myocilin, corresponding to a severe glaucoma-causing mutation (Tyr437His) in human subjects, exhibit a weak, if any, glaucoma phenotype. To address possible protein-level discrepancies between mouse and human OLFs, which might lead to this outcome, biophysical properties of mouse OLF were characterized for comparison with those of human OLF. The 1.55 Å resolution crystal structure of mouse OLF reveals an asymmetric 5-bladed β-propeller that is nearly indistinguishable from previous structures of human OLF. Wild-type and selected mutant mouse OLFs mirror thermal stabilities of their human OLF counterparts, including characteristic stabilization in the presence of calcium. Mouse OLF forms thioflavin T-positive aggregates with a similar end-point morphology as human OLF, but amyloid aggregation kinetic rates of mouse OLF are faster than human OLF. Simulations and experiments support the interpretation that kinetics of mouse OLF are faster because of a decreased charge repulsion arising from more neutral surface electrostatics. Taken together, phenotypic differences observed in mouse and human studies of mutant myocilin could be a function of aggregation kinetics rates, which would alter the lifetime of putatively toxic protofibrillar intermediates.
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Affiliation(s)
- Athéna C Patterson-Orazem
- School of Chemistry & Biochemistry , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Shannon E Hill
- School of Chemistry & Biochemistry , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Yiming Wang
- Department of Chemical & Biomolecular Engineering , North Carolina State University , Raleigh , North Carolina 27695-7905 , United States
| | - Iramofu M Dominic
- School of Chemistry & Biochemistry , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
| | - Carol K Hall
- Department of Chemical & Biomolecular Engineering , North Carolina State University , Raleigh , North Carolina 27695-7905 , United States
| | - Raquel L Lieberman
- School of Chemistry & Biochemistry , Georgia Institute of Technology , Atlanta , Georgia 30332-0400 , United States
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28
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van der Heide CJ, Alward WL, Flamme-Wiese M, Riker M, Syed NA, Anderson MG, Carter K, Kuehn MH, Stone EM, Mullins RF, Fingert JH. Histochemical Analysis of Glaucoma Caused by a Myocilin Mutation in a Human Donor Eye. Ophthalmol Glaucoma 2018; 1:132-138. [PMID: 30906929 PMCID: PMC6425711 DOI: 10.1016/j.ogla.2018.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
OBJECTIVE Mutations in myocilin (MYOC) may cause either juvenile open angle glaucoma (JOAG) or adult-onset primary open angle glaucoma (POAG). MYOC encodes a glycoprotein that is normally secreted from trabecular meshwork cells that regulate intraocular pressure. Prior in vitro, transgenic rodent, and organ culture experiments have suggested that abnormal accumulation of MYOC protein within trabecular meshwork cells is a key step in glaucoma pathophysiology. We investigated the pathogenesis of MYOC glaucoma by examining a donor eye from a patient with JOAG caused by a Tyr437His MYOC mutation. DESIGN Case-control, immunohistochemical study of a donor eye from a patient with JOAG caused by a Tyr437His MYOC mutation and age-matched control donor eyes. SUBJECTS An eye from a 59-year-old male with JOAG caused by a Tyr437His MYOC mutation and eyes from five donors (ages 51-66) with no known ocular disease were examined. METHODS Frozen fixed sections of the iridocorneal angle were prepared from the donor eyes of the MYOC glaucoma patient and control eyes. We used antibodies directed against MYOC, collagen IV, and BiP/GRP78 as well as wheat germ agglutinin and concanavalin A lectins to localize MYOC protein in the trabecular meshwork. MAIN OUTCOME MEASURE Qualitative comparison of MYOC protein labeling and localization in the trabecular meshwork of donor eyes from a glaucoma patient with a MYOC mutation and from control subjects. RESULTS Using immunohistochemistry, we detected more abundant MYOC protein within the trabecular meshwork of the MYOC glaucoma patient's eye than in control eyes. We further localized MYOC protein within the trabecular meshwork cells of the MYOC glaucoma patient's eye by co-labeling with the endoplasmic reticulum (ER) marker GRP78 (BiP). Little to no MYOC was identified within the trabecular meshwork cells of control eyes. Minimal extracellular MYOC was detected in both MYOC glaucoma eyes and control eyes. CONCLUSIONS This is the first histopathological analysis of an eye from a glaucoma patient with a MYOC mutation. Furthermore, this analysis supports our model of MYOC-associated glaucoma, in which MYOC mutations cause abnormal intracellular retention of MYOC within the ER of trabecular meshwork cells as a key step towards development of glaucoma.
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Affiliation(s)
- Carly J. van der Heide
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
- Department of Ophthalmology and Visual Sciences, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Molecular Physiology and Biophysics, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Wallace L.M. Alward
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
- Department of Ophthalmology and Visual Sciences, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Miles Flamme-Wiese
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
- Department of Ophthalmology and Visual Sciences, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Megan Riker
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
- Department of Ophthalmology and Visual Sciences, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Nasreen A. Syed
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
- Department of Pathology, Carver College of Medicine,
University of Iowa, Iowa City, IA, USA
| | - Michael G. Anderson
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
- Department of Ophthalmology and Visual Sciences, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
- Department of Molecular Physiology and Biophysics, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
- Center for Prevention and Treatment of Visual Loss, Iowa
City Veterans Administration Medical Center, Iowa City, IA 52242, USA
| | - Keith Carter
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
| | - Markus H. Kuehn
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
- Department of Ophthalmology and Visual Sciences, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Edwin M. Stone
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
- Department of Ophthalmology and Visual Sciences, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Robert F. Mullins
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
- Department of Ophthalmology and Visual Sciences, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
| | - John H. Fingert
- institute for Vision Research, University of Iowa, Iowa
City, IA, USA
- Department of Ophthalmology and Visual Sciences, Carver
College of Medicine, University of Iowa, Iowa City, IA, USA
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29
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Guo C, Qu X, Rangaswamy N, Leehy B, Xiang C, Rice D, Prasanna G. A murine glaucoma model induced by rapid in vivo photopolymerization of hyaluronic acid glycidyl methacrylate. PLoS One 2018; 13:e0196529. [PMID: 29949582 PMCID: PMC6021085 DOI: 10.1371/journal.pone.0196529] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 04/13/2018] [Indexed: 12/04/2022] Open
Abstract
Glaucoma is an optic neuropathy commonly associated with elevated intraocular pressure (IOP) resulting in progressive loss of retinal ganglion cells (RGCs) and optic nerve degeneration, leading to blindness. New therapeutic approaches that better preserve the visual field by promoting survival and health of RGCs are highly needed since RGC death occurs despite good IOP control in glaucoma patients. We have developed a novel approach to reliably induce chronic IOP elevation in mouse using a photopolymerizable biomatrix, hyaluronic acid glycidyl methacrylate. This is achieved by rapid in vivo crosslinking of the biomatrix at the iridocorneal angle by a flash of ultraviolet A (UVA) light to impede the aqueous outflow pathway with a controllable manner. Sustained IOP elevation was induced after a single manipulation and was maintained at ~45% above baseline for >4 weeks. Significant thinning of the inner retina and ~35% reduction in RGCs and axons was noted within one month of IOP elevation. Optic nerve degeneration showed positive correlation with cumulative IOP elevation. Activation of astrocytes and microglia appeared to be an early event in response to IOP elevation preceding detectable RGC and axon loss. Attenuated glial reactivity was noted at later stage where significant RGC/axon loss had occurred suggesting astrocytes and microglia may play different roles over the course of glaucomatous degeneration. This novel murine glaucoma model is reproducible and displays cellular changes that recapitulate several pathophysiological features of glaucoma.
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Affiliation(s)
- Chenying Guo
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
- * E-mail: (GP); (CG)
| | - Xin Qu
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Nalini Rangaswamy
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Barrett Leehy
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Chuanxi Xiang
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Dennis Rice
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
| | - Ganesh Prasanna
- Department of Ophthalmology, Novartis Institutes for BioMedical Research, Cambridge, MA, United States of America
- * E-mail: (GP); (CG)
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30
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Raghunathan VK, Benoit J, Kasetti R, Zode G, Salemi M, Phinney BS, Keller KE, Staverosky JA, Murphy CJ, Acott T, Vranka J. Glaucomatous cell derived matrices differentially modulate non-glaucomatous trabecular meshwork cellular behavior. Acta Biomater 2018. [PMID: 29524673 DOI: 10.1016/j.actbio.2018.02.037] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Ocular hypertension is a causal risk-factor to developing glaucoma. This is associated with stiffening of the trabecular meshwork (TM), the primary site of resistance to aqueous-humor-outflow. The mechanisms underlying this stiffening or how pathologic extracellular matrix (ECM) affects cell function are poorly understood. It is recognized that mechanotransduction systems allow cells to sense and translate the intrinsic biophysical properties of ECM into intracellular signals to control gene transcription, protein expression, and cell behavior. Using an anterior segment perfusion model, we document that there are significantly more low flow regions that are much stiffer, and fewer high flow regions that are less stiff in glaucomatous TM (GTM) when compared to non-glaucomatous TMs (NTM). GTM tissue also has fewer cells overall when compared with NTM tissue. In order to study the role of pathologic ECM in glaucoma disease progression, we conducted studies using cell derived matrices (CDM). First, we characterized the mechanics, composition and organization of fibronectin in ECM deposited by GTM and NTM cells treated with glucocorticosteroids. Then, we determined that these GTM-derived ECM are able to induce stiffening of normal NTM cells, and alter their gene/protein expression to resemble that of a glaucomatous phenotype. Further, we demonstrate that GTM-derived ECM causes endoplasmic reticular stress in NTM. They also became resistant to being reorganized by these NTM cells. These phenomena were exacerbated by ECMs obtained from steroid treated glaucoma model groups. Collectively, our data demonstrates that CDMs represent a novel tool for the study of bidirectional interactions between TM cells and their immediate microenvironment. STATEMENT OF SIGNIFICANCE Extracellular matrix (ECM) changes are prevalent in a number of diseases. The precise mechanisms by which changes in the ECM contribute to disease progression is unclear, primarily due to absence of appropriate models. Here, using glaucoma as a disease model, we document changes in cell derived matrix (CDM) and tissue mechanics that contribute to the pathology. Subsequently, we determine the effect that ECMs from diseased and healthy individuals have on healthy cell behaviors. Data emanating from this study demonstrate that CDMs are a potent tool for the study of cell-ECM interactions.
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31
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Hernandez H, Millar JC, Curry SM, Clark AF, McDowell CM. BMP and Activin Membrane Bound Inhibitor Regulates the Extracellular Matrix in the Trabecular Meshwork. Invest Ophthalmol Vis Sci 2018; 59:2154-2166. [PMID: 29801150 PMCID: PMC5915111 DOI: 10.1167/iovs.17-23282] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/22/2018] [Indexed: 01/18/2023] Open
Abstract
Purpose The trabecular meshwork (TM) has an important role in the regulation of aqueous humor outflow and IOP. Regulation of the extracellular matrix (ECM) by TGFβ2 has been studied extensively. Bone morphogenetic protein (BMP) and activin membrane-bound inhibitor (BAMBI) has been shown to inhibit or modulate TGFβ2 signaling. We investigate the role of TGFβ2 and BAMBI in the regulation of TM ECM and ocular hypertension. Methods Mouse TM (MTM) cells were isolated from B6;129S1-Bambitm1Jian/J flox mice, characterized for TGFβ2 and dexamethasone (DEX)-induced expression of fibronectin, collagen-1, collagen-4, laminin, α-smooth muscle actin, cross-linked actin networks (CLANs) formation, and DEX-induced myocilin (MYOC) expression. MTM cells were transduced with Ad5.GFP to identify transduction efficiency. MTM cells and mouse eyes were transduced with Ad5.Null, Ad5.Cre, Ad5.TGFβ2, or Ad5.TGFβ2 + Ad5.Cre to evaluate the effect on ECM production, IOP, and outflow facility. Results MTM cells express TM markers and respond to DEX and TGFβ2. Ad5.GFP at 100 MOI had the highest transduction efficiency. Bambi knockdown by Ad5.Cre and Ad5.TGFβ2 increased fibronectin, collagen-1, and collagen-4 in TM cells in culture and tissue. Ad5.Cre, Ad5.TGFβ2, and Ad5.TGFβ2 + Ad5.Cre each significantly induced ocular hypertension and lowered aqueous humor outflow facility in transduced eyes. Conclusions We show for the first time to our knowledge that knockdown of Bambi alters ECM expression in cultured cells and mouse TM, reduces outflow facility, and causes ocular hypertension. These data provide a novel insight into the development of glaucomatous TM damage and identify BAMBI as an important regulator of TM ECM and ocular hypertension.
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Affiliation(s)
- Humberto Hernandez
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - J. Cameron Millar
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Stacy M. Curry
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Abbot F. Clark
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Colleen M. McDowell
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
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Yao YH, Wang YQ, Fang WF, Zhang L, Yang JH, Zhu YH. A recurrent G367R mutation in MYOC associated with juvenile open angle glaucoma in a large Chinese family. Int J Ophthalmol 2018; 11:369-374. [PMID: 29600168 DOI: 10.18240/ijo.2018.03.04] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 12/22/2017] [Indexed: 11/23/2022] Open
Abstract
AIM To identify the mutations of MYOC, OPTN, CYP1B1 and WDR36 in a large Chinese family affected by juvenile open angle glaucoma (JOAG). METHODS Of 114 members of one family were recruited in this study. Blood samples from twelve members of this pedigree were collected for further research. As a control, 100 unrelated subjects were recruited from the same hospital. The exon and flanking intron sequences of candidate genes were amplified using the polymerase chain reaction and direct DNA sequencing. RESULTS The proband (III:10) was a seventy-three years old woman with binocular JOAG at the age of 31. A recurrent heterozygous mutation (c.1099G>A) of MYOC was identified in the three JOAG patients and another suspect. This transition was located in the first base pair of codon 367 (GGA>AGA) in exon 3 of MYOC and was predicted to be a missense substitution of glycine to arginine (p.G367R) in myocilin. Mutations in OPTN, CYP1B1 or WDR36 were not detected in this study. The G367R mutation was not present in unaffected family members or in 100 ethnically matched controls. Other variants of the coding regions of candidate genes were not detected in all participants. To date, this family was the largest to have been identified as carrying a certain MYOC mutation in China, further evidence of a founder effect for the G367R MYOC mutant was provided by our data. CONCLUSION A MYOC c.1099G>A mutation in an autosomal dominant JOAG family is identified and the characteristic phenotypes among the patients are summarized. Genetic testing could be utilized in high-risk populations and be helpful not only for genetic counseling, but also for early diagnosis and treatment of affected patients or carriers of inherited JOAG.
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Affiliation(s)
- Yi-Hua Yao
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Ya-Qin Wang
- Department of Ophthalmology, Taihe Hospital, Shiyan 442008, Hubei Province, China.,Hubei University of Medicine, Shiyan 442008, Hubei Province, China
| | - Wei-Fang Fang
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Liu Zhang
- Fuzhou Eye Hospital, Fuzhou 350007, Fujian Province, China
| | - Ju-Hua Yang
- Biomedical Engineering Center of Fujian Medical University, Fuzhou 350004, Fujian Province, China
| | - Yi-Hua Zhu
- Department of Ophthalmology, the First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
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Patel GC, Liu Y, Millar JC, Clark AF. Glucocorticoid receptor GRβ regulates glucocorticoid-induced ocular hypertension in mice. Sci Rep 2018; 8:862. [PMID: 29339763 PMCID: PMC5770444 DOI: 10.1038/s41598-018-19262-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 12/21/2017] [Indexed: 01/26/2023] Open
Abstract
Prolonged glucocorticoid (GC) therapy can cause GC-induced ocular hypertension (OHT), which if left untreated progresses to iatrogenic glaucoma and permanent vision loss. The alternatively spliced isoform of glucocorticoid receptor GRβ acts as dominant negative regulator of GR activity, and it has been shown that overexpressing GRβ in trabecular meshwork (TM) cells inhibits GC-induced glaucomatous damage in TM cells. The purpose of this study was to use viral vectors to selectively overexpress the GRβ isoform in the TM of mouse eyes treated with GCs, to precisely dissect the role of GRβ in regulating steroid responsiveness. We show that overexpression of GRβ inhibits GC effects on MTM cells in vitro and GC-induced OHT in mouse eyes in vivo. Ad5 mediated GRβ overexpression reduced the GC induction of fibronectin, collagen 1, and myocilin in TM of mouse eyes both in vitro and in vivo. GRβ also reversed DEX-Ac induced IOP elevation, which correlated with increased conventional aqueous humor outflow facility. Thus, GRβ overexpression reduces effects caused by GCs and makes cells more resistant to GC treatment. In conclusion, our current work provides the first evidence of the in vivo physiological role of GRβ in regulating GC-OHT and GC-mediated gene expression in the TM.
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Affiliation(s)
- Gaurang C Patel
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - Yang Liu
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, TX, 76107, United States.
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Lopez NN, Patel GC, Raychaudhuri U, Aryal S, Phan TN, Clark AF, Millar JC. Anterior chamber perfusion versus posterior chamber perfusion does not influence measurement of aqueous outflow facility in living mice by constant flow infusion. Exp Eye Res 2017; 164:95-108. [PMID: 28822760 DOI: 10.1016/j.exer.2017.08.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 07/13/2017] [Accepted: 08/14/2017] [Indexed: 11/25/2022]
Abstract
Mice are now routinely utilized in studies of aqueous humor outflow dynamics. In particular, conventional aqueous outflow facility (C) is routinely measured via perfusion of the aqueous chamber by a number of laboratories. However, in mouse eyes perfused ex-vivo, values for C are variable depending upon whether the perfusate is introduced into the posterior chamber (PC) versus the anterior chamber (AC). Perfusion via the AC leads to posterior bowing of the iris, and traction on the iris root/scleral spur, which may increase C. Perfusion via the PC does not yield this effect. But the equivalent situation in living mice has not been investigated. We sought to determine whether AC versus PC perfusion of the living mouse eye may lead to different values for C. All experiments were conducted in C57BL/6J mice (all ♀) between the ages of 20 and 30 weeks. Mice were divided into groups of 3-4 animals each. In all groups, both eyes were perfused. C was measured in groups 1 and 2 by constant flow infusion (from a 50 μL microsyringe) via needle placement in the AC, and in the PC, respectively. To investigate the effect of ciliary muscle (CM) tone on C, groups 3 and 4 were perfused live via the AC or PC with tropicamide (muscarinic receptor antagonist) added to the perfusate at a concentration of 100 μM. To investigate immediate effect of euthanasia, groups 5 and 6 were perfused 15-30 min after death via the AC or PC. To investigate the effect of CM tone on C immediately following euthanasia, groups 7 and 8 were perfused 15-30 min after death via the AC or PC with tropicamide added to the perfusate at a concentration of 100 μM. C in Groups 1 (AC perfusion) and 2 (PC perfusion) was computed to be 19.5 ± 0.8 versus 21.0 ± 2.1 nL/min/mmHg, respectively (mean ± SEM, p > 0.4, not significantly different). In live animals in which tropicamide was present in the perfusate, C in Group 3 (AC perfusion) was significantly greater than C in Group 4 (PC perfusion) (22.0 ± 4.0 versus 14.0 ± 2.0 nL/min/mmHg, respectively, p = 0.0021). In animals immediately following death, C in groups 5 (AC perfusion) and 6 (PC perfusion) was computed to be 21.2 ± 2.0 versus 22.8 ± 1.4 nL/min/mmHg, respectively (mean ± SEM, p = 0.1196, not significantly different). In dead animals in which tropicamide was present in the perfusate, C in group 7 (AC perfusion) was greater than C in group 8 (PC perfusion) (20.6 ± 1.4 versus 14.2 ± 2.6 nL/min/mmHg, respectively, p < 0.0001). C in eyes in situ in living mice or euthanized animals within 15-30 min post mortem is not significantly different when measured via AC perfusion or PC perfusion. In eyes of live or freshly euthanized mice, C is greater when measured via AC versus PC perfusion when tropicamide (a mydriatic and cycloplegic agent) is present in the perfusate.
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Affiliation(s)
- Navita N Lopez
- North Texas Eye Research Institute (NTERI), University of North Texas Health Science Center (UNTHSC), 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Gaurang C Patel
- North Texas Eye Research Institute (NTERI), University of North Texas Health Science Center (UNTHSC), 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Urmimala Raychaudhuri
- North Texas Eye Research Institute (NTERI), University of North Texas Health Science Center (UNTHSC), 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Subhash Aryal
- Department of Biostatistics and Epidemiology, University of North Texas Health Science Center (UNTHSC), 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Tien N Phan
- North Texas Eye Research Institute (NTERI), University of North Texas Health Science Center (UNTHSC), 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - Abbot F Clark
- North Texas Eye Research Institute (NTERI), University of North Texas Health Science Center (UNTHSC), 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA
| | - J Cameron Millar
- North Texas Eye Research Institute (NTERI), University of North Texas Health Science Center (UNTHSC), 3500 Camp Bowie Boulevard, Fort Worth, TX 76107, USA.
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Hernandez H, Medina-Ortiz WE, Luan T, Clark AF, McDowell CM. Crosstalk Between Transforming Growth Factor Beta-2 and Toll-Like Receptor 4 in the Trabecular Meshwork. Invest Ophthalmol Vis Sci 2017; 58:1811-1823. [PMID: 28346614 PMCID: PMC5374883 DOI: 10.1167/iovs.16-21331] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Purpose The trabecular meshwork (TM) is involved in the outflow of aqueous humor and intraocular pressure (IOP) regulation. Regulation of the extracellular matrix (ECM) by TGFβ2 signaling pathways in the TM has been extensively studied. Recent evidence has implicated toll-like receptor 4 (TLR4) in the regulation of ECM and fibrogenesis in liver, kidney, lung, and skin. Here, we investigated the role of TGFβ2-TLR4 signaling crosstalk in the regulation of the ECM in the TM and ocular hypertension. Methods Cross sections of human donor eyes, primary human TM cells in culture, and dissected mouse TM rings were used to determine Tlr4 expression in the TM. Trabecular meshwork cells in culture were treated with TGFβ2 (5 ng/mL), TLR4 inhibitor (TAK-242, 15 μM), and a TLR4 ligand (cellular fibronectin isoform [cFN]-EDA). A/J (n = 13), AKR/J (n = 7), BALBc/J (n = 8), C3H/HeJ (n = 20), and C3H/HeOuJ (n = 10) mice were injected intravitreally with adenovirus 5 (Ad5).hTGFβ2c226s/c228s in one eye, with the uninjected contralateral eye serving as a control. Conscious IOP measurements were taken using a TonoLab rebound tonometer. Results Toll-like receptor 4 is expressed in the human and mouse TM. Inhibition of TLR4 signaling in the presence of TGFβ2 decreases fibronectin expression. Activation of TLR4 by cFN-EDA in the presence of TGFβ2 further increases fibronectin, laminin, and collagen-1 expression, and TLR4 signaling inhibition blocks this effect. Ad5.hTGFβ2c226s/c228s induces ocular hypertension in wild-type mice but has no effect in Tlr4 mutant (C3H/HeJ) mice. Conclusions These studies identify TGFβ2-TLR4 crosstalk as a novel pathway involved in ECM regulation in the TM and ocular hypertension. These data further explain the complex mechanisms involved in the development of glaucomatous TM damage.
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Affiliation(s)
- Humberto Hernandez
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Wanda E Medina-Ortiz
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Tomi Luan
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Colleen M McDowell
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
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Kasetti RB, Phan TN, Millar JC, Zode GS. Expression of Mutant Myocilin Induces Abnormal Intracellular Accumulation of Selected Extracellular Matrix Proteins in the Trabecular Meshwork. Invest Ophthalmol Vis Sci 2017; 57:6058-6069. [PMID: 27820874 PMCID: PMC5102566 DOI: 10.1167/iovs.16-19610] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Abnormal accumulation of extracellular matrix (ECM) in the trabecular meshwork (TM) is associated with decreased aqueous humor outflow facility and IOP elevation in POAG. Previously, we have developed a transgenic mouse model of POAG (Tg-MYOCY437H) by expressing human mutant myocilin (MYOC), a known genetic cause of POAG. The purpose of this study is to examine whether expression of mutant myocilin leads to reduced outflow facility and abnormal ECM accumulation in Tg-MYOCY437H mice and in cultured human TM cells. Methods Conscious IOP was measured at various ages of Tg-MYOCY437H mice using a rebound tonometer. Outflow facility was measured in 10-month-old Tg-MYOCY437H mice. Selected ECM proteins were examined in human TM-3 cells stably expressing mutant myocilin and primary human TM cells (n = 4) as well as in the TM of Tg-MYOCY437H mice by real-time PCR, Western blotting, and immunostaining. Furthermore, TM cells expressing WT or mutant myocilin were treated with 5 mM sodium 4-phenylbutyrate (PBA), and ECM proteins were examined by Western blot and immunostaining. Results Starting from 3 months of age, Tg-MYOCY437H mice exhibited significant IOP elevation compared with wild-type (WT) littermates. Outflow facility was significantly reduced in Tg-MYOCY437H mice (0.0195 μl/min/mm Hg in Tg-MYOCY437H vs. 0.0332 μl/min/mm Hg in WT littermates). Increased accumulation of fibronectin, elastin, and collagen type IV and I was observed in the TM of Tg-MYOCY437H mice compared with WT littermates. Furthermore, increased ECM proteins were also associated with induction of endoplasmic reticulum (ER) stress markers, GRP78 and CHOP in the TM of Tg-MYOCY437H mice. Human TM-3 cells stably expressing DsRed-tagged Y437H mutant MYOC exhibited inhibition of myocilin secretion and its intracellular accumulation compared with TM cells expressing WT MYOC. Expression of mutant MYOC in TM-3 cells or human primary TM cells induced ER stress and also increased intracellular protein levels of fibronectin, elastin, laminin, and collagen IV and I. In addition, TM-3 cells expressing mutant myocilin exhibited reduced active forms of matrix metalloproteinase (MMP)-2 and MMP-9 in conditioned medium compared with TM-3 cells expressing WT myocilin. Interestingly, both intracellularly accumulated fibronectin and collagen I colocalized with mutant myocilin and also with ER marker KDEL further suggesting intracellular accumulation of these proteins in the ER of TM cells. Furthermore, reduction of ER stress via PBA decreased selected ECM proteins in primary TM cells. Conclusions These studies demonstrate that mutant myocilin induces abnormal ECM accumulation in the ER of TM cells, which may be responsible for reduced outflow facility and IOP elevation in myocilin-associated glaucoma.
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Affiliation(s)
- Ramesh B Kasetti
- North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Texas, United States
| | - Tien N Phan
- North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Texas, United States
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Texas, United States
| | - Gulab S Zode
- North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Texas, United States
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Patel GC, Phan TN, Maddineni P, Kasetti RB, Millar JC, Clark AF, Zode GS. Dexamethasone-Induced Ocular Hypertension in Mice: Effects of Myocilin and Route of Administration. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:713-723. [PMID: 28167045 DOI: 10.1016/j.ajpath.2016.12.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 12/05/2016] [Accepted: 12/08/2016] [Indexed: 11/24/2022]
Abstract
Glucocorticoid (GC)-induced ocular hypertension (OHT) is a serious adverse effect of prolonged GC therapy that can lead to iatrogenic glaucoma and permanent vision loss. An appropriate mouse model can help us understand precise molecular mechanisms and etiology of GC-induced OHT. We therefore developed a novel, simple, and reproducible mouse model of GC-induced OHT. GC-induced myocilin expression in the trabecular meshwork (TM) has been suggested to play an important role in GC-induced OHT. We further determined whether myocilin contributes to GC-OHT. C57BL/6J mice received weekly periocular conjunctival fornix injections of a dexamethasone-21-acetate (DEX-Ac) formulation. Intraocular pressure (IOP) elevation was relatively rapid and significant, and correlated with reduced conventional outflow facility. Nighttime IOPs were higher in ocular hypertensive eyes compared to daytime IOPs. DEX-Ac treatment led to increased expression of fibronectin, collagen I, and α-smooth muscle actin in the TM in mouse eyes. No changes in body weight indicated no systemic toxicity associated with DEX-Ac treatment. Wild-type mice showed increased myocilin expression in the TM on DEX-Ac treatment. Both wild-type and Myoc-/- mice had equivalent and significantly elevated IOP with DEX-Ac treatment every week. In conclusion, our mouse model mimics many aspects of GC-induced OHT in humans, and we further demonstrate that myocilin does not play a major role in DEX-induced OHT in mice.
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Affiliation(s)
- Gaurang C Patel
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Tien N Phan
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Prabhavathi Maddineni
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Ramesh B Kasetti
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - J Cameron Millar
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas.
| | - Gulab S Zode
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas.
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McDowell CM, Hernandez H, Mao W, Clark AF. Gremlin Induces Ocular Hypertension in Mice Through Smad3-Dependent Signaling. Invest Ophthalmol Vis Sci 2015; 56:5485-92. [PMID: 26284554 DOI: 10.1167/iovs.15-16993] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
PURPOSE Transforming growth factor-β2 induces extracellular matrix (ECM) remodeling, which likely contributes to the defective function of the trabecular meshwork (TM) leading to glaucomatous ocular hypertension. Bone morphogenetic proteins (BMPs) inhibit these profibrotic effects of TGFβ2. The BMP antagonist gremlin is elevated in glaucomatous TM cells and increases IOP in an ex vivo perfusion culture model. The purpose of this study was to determine whether gremlin regulates ECM proteins in the TM, signals through the Smad3-dependent pathway, and induces ocular hypertension in mice. METHODS Ad5.Gremlin or Ad5.TGFβ2 was injected intravitreally into one eye of each mouse. Intraocular pressure measurements were taken using a TonoLab tonometer. Gremlin, TGFβ2, fibronectin (FN), and collagen-1 (Col-1) expression in the TM was determined by immunofluorescence, Western immunoblot, and quantitative (q)PCR analyses. RESULTS Ad5.Gremlin or Ad5.TGFβ2 each caused significant IOP elevation in mice. Immunofluorescence and Western blot analysis demonstrated that gremlin and TGFβ2 reciprocally increased the expression of each other, and both increased FN expression in the TM and surrounding tissues. Ad5.Gremlin elevated IOP and increased Fn and Col-1 gene expression in the TM of Smad3 wild-type (WT) mice, but had no effect in Smad3 HET or Smad3 KO mice. CONCLUSIONS Our results demonstrate that intravitreal injections of either Ad5.Gremlin or Ad5.TGFβ2 elevate IOP and upregulate the ECM protein FN in the TM of mice. These data show that gremlin signals through the Smad3-dependent pathway in the TM to elevate IOP. We determined for the first time gremlin's role in inducing ocular hypertension in an in vivo model system.
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Stothert AR, Fontaine SN, Sabbagh JJ, Dickey CA. Targeting the ER-autophagy system in the trabecular meshwork to treat glaucoma. Exp Eye Res 2015; 144:38-45. [PMID: 26302411 DOI: 10.1016/j.exer.2015.08.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Revised: 07/23/2015] [Accepted: 08/18/2015] [Indexed: 12/19/2022]
Abstract
A major drainage network involved in aqueous humor dynamics is the conventional outflow pathway, which is gated by the trabecular meshwork (TM). The TM acts as a molecular sieve, providing resistance to aqueous outflow, which is responsible for regulating intraocular pressure (IOP). If the TM is damaged, aqueous outflow is impaired, IOP increases and glaucoma can manifest. Mutations in the MYOC gene cause hereditary primary open-angle glaucoma (POAG) by promoting the abnormal amyloidosis of the myocilin protein in the endoplasmic reticulum (ER), leading to ER stress-induced TM cell death. Myocilin accumulation is observed in approximately 70-80% of all glaucoma cases suggesting that environmental or other genetic factors may also promote myocilin toxicity. For example, simply preventing myocilin glycosylation is sufficient to promote its abnormal accretion. These myocilin amyloids are unique as there are no other known pathogenic proteins that accumulate within the ER of TM cells and cause toxicity. Moreover, this pathogenic accumulation only kills TM cells, despite expression of this protein in other cell types, suggesting that another modifier exclusive to the TM participates in the proteotoxicity of myocilin. ER autophagy (reticulophagy) is one of the pathways essential for myocilin clearance that can be impacted dramatically by aging and other environmental factors such as nutrition. This review will discuss the link between myocilin and autophagy, evaluating the role of this degradation pathway in glaucoma as well as its potential as a therapeutic target.
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Affiliation(s)
- Andrew R Stothert
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA
| | - Sarah N Fontaine
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA
| | - Jonathan J Sabbagh
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA
| | - Chad A Dickey
- Department of Molecular Medicine, Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA.
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Quigley HA. The contribution of the sclera and lamina cribrosa to the pathogenesis of glaucoma: Diagnostic and treatment implications. PROGRESS IN BRAIN RESEARCH 2015; 220:59-86. [PMID: 26497785 DOI: 10.1016/bs.pbr.2015.04.003] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Glaucoma, the second most common cause of world blindness, results from loss of retinal ganglion cells (RGC). RGC die as a consequence of injury to their axons, as they pass through the transition between the environment within the eye and that of the retrobulbar optic nerve, as they course to central visual centers. At the optic nerve head (ONH), axonal transport becomes abnormal, at least in part due to the effect of strain induced by intraocular pressure (IOP) on the sclera and ONH. Animal glaucoma models provide the ability to study how alterations in ocular connective tissues affect this pathological process. New therapeutic interventions are being investigated to mitigate glaucoma blindness by modifying the remodeling of ocular tissues in glaucoma. Some genetically altered mice are resistant to glaucoma damage, while treatment of the sclera with cross-linking agents makes experimental mouse glaucoma damage worse. Inhibition of transforming growth factor β activity is strikingly protective. Treatments that alter the response of ocular connective tissues to IOP may be effective in protecting those with glaucoma from vision loss.
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Affiliation(s)
- Harry A Quigley
- Glaucoma Center of Excellence, Wilmer Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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Using genetic mouse models to gain insight into glaucoma: Past results and future possibilities. Exp Eye Res 2015; 141:42-56. [PMID: 26116903 DOI: 10.1016/j.exer.2015.06.019] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Revised: 06/16/2015] [Accepted: 06/23/2015] [Indexed: 12/18/2022]
Abstract
While all forms of glaucoma are characterized by a specific pattern of retinal ganglion cell death, they are clinically divided into several distinct subclasses, including normal tension glaucoma, primary open angle glaucoma, congenital glaucoma, and secondary glaucoma. For each type of glaucoma there are likely numerous molecular pathways that control susceptibility to the disease. Given this complexity, a single animal model will never precisely model all aspects of all the different types of human glaucoma. Therefore, multiple animal models have been utilized to study glaucoma but more are needed. Because of the powerful genetic tools available to use in the laboratory mouse, it has proven to be a highly useful mammalian system for studying the pathophysiology of human disease. The similarity between human and mouse eyes coupled with the ability to use a combination of advanced cell biological and genetic tools in mice have led to a large increase in the number of studies using mice to model specific glaucoma phenotypes. Over the last decade, numerous new mouse models and genetic tools have emerged, providing important insight into the cell biology and genetics of glaucoma. In this review, we describe available mouse genetic models that can be used to study glaucoma-relevant disease/pathobiology. Furthermore, we discuss how these models have been used to gain insights into ocular hypertension (a major risk factor for glaucoma) and glaucomatous retinal ganglion cell death. Finally, the potential for developing new mouse models and using advanced genetic tools and resources for studying glaucoma are discussed.
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Elevation of intraocular pressure in rodents using viral vectors targeting the trabecular meshwork. Exp Eye Res 2015; 141:33-41. [PMID: 26025608 DOI: 10.1016/j.exer.2015.04.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/20/2015] [Accepted: 04/05/2015] [Indexed: 01/30/2023]
Abstract
Rodents are increasingly being used as glaucoma models to study ocular hypertension, optic neuropathy, and retinopathy. A number of different techniques are used to elevate intraocular pressure in rodent eyes by artificially obstructing the aqueous outflow pathway. Another successful technique to induce ocular hypertension is to transduce the trabecular meshwork of rodent eyes with viral vectors expressing glaucoma associated transgenes to provide more relevant models of glaucomatous damage to the trabecular meshwork. This technique has been used to validate newly discovered glaucoma pathogenesis pathways as well as to develop rodent models of primary open angle glaucoma. Ocular hypertension has successfully been induced by adenovirus 5 mediated delivery of mutant MYOC, bioactivated TGFβ2, SFRP1, DKK1, GREM1, and CD44. Advantages of this approach are: selective tropism for the trabecular meshwork, the ability to use numerous mouse strains, and the relatively rapid onset of IOP elevation. Disadvantages include mild-to-moderate ocular inflammation induced by the Ad5 vector and sometimes transient transgene expression. Current efforts are focused at discovering less immunogenic viral vectors that have tropism for the trabecular meshwork and drive sufficient transgene expression to induce ocular hypertension. This viral vector approach allows rapid proof of concept studies to study glaucomatous damage to the trabecular meshwork without the expensive and time-consuming generation of transgenic mouse lines.
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Joe MK, Nakaya N, Abu-Asab M, Tomarev SI. Mutated myocilin and heterozygous Sod2 deficiency act synergistically in a mouse model of open-angle glaucoma. Hum Mol Genet 2015; 24:3322-34. [PMID: 25740847 DOI: 10.1093/hmg/ddv082] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 03/02/2015] [Indexed: 11/14/2022] Open
Abstract
Glaucoma is a multifactorial optic neuropathy characterized by retinal ganglion cell (RGC) death and axonal degeneration leading to irreversible blindness. Mutations in the myocilin (MYOC) gene are the most common genetic factors of primary open-angle glaucoma. To develop a genetic mouse model induced by the synergistic interaction of mutated myocilin and another significant risk factor, oxidative stress, we produced double-mutant mice (Tg-MYOC(Y437H/+)/Sod2(+/-)) bearing human MYOC with a Y437H point mutation and a heterozygous deletion of the gene for the primary antioxidant enzyme, superoxide dismutase 2 (SOD2). Sod2 is broadly expressed in most tissues including the trabecular meshwork (TM) and heterozygous Sod2 knockout mice exhibit the reduced SOD2 activity and oxidative stress in all studied tissues. Accumulation of Y437H myocilin in the TM induced endoplasmic reticulum stress and led to a 45% loss of smooth muscle alpha-actin positive cells in the eye drainage structure of 10- to 12-month-old Tg-MYOC(Y437H/+)/Sod2(+/-) mice as compared with wild-type littermates. Tg-MYOC(Y437H/+)/Sod2(+/-) mice had higher intraocular pressure, lost about 37% of RGCs in the peripheral retina, and exhibited axonal degeneration in the retina and optic nerve as compared with their wild-type littermates. Single-mutant littermates containing MYOC(Y437H/+) or Sod2(+/-) exhibited no significant pathological changes until 12 months of age. Additionally, we observed elevated expression of endothelial leukocyte adhesion molecule-1, a human glaucoma marker, in the TM of Tg-MYOC(Y437H/+)/Sod2(+/-) mice. This is the first reported animal glaucoma model that combines expression of a glaucoma-causing mutant gene and an additional mutation mimicking a deleterious environment factor that acts synergistically.
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Affiliation(s)
- Myung Kuk Joe
- Section on Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology and
| | - Naoki Nakaya
- Section on Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology and
| | - Mones Abu-Asab
- Histology Core, National Eye Institute, NIH, Bethesda, MD 20895, USA
| | - Stanislav I Tomarev
- Section on Retinal Ganglion Cell Biology, Laboratory of Retinal Cell and Molecular Biology and
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Li G, Farsiu S, Qiu J, Dixon A, Song C, McKinnon SJ, Yuan F, Gonzalez P, Stamer WD. Disease progression in iridocorneal angle tissues of BMP2-induced ocular hypertensive mice with optical coherence tomography. Mol Vis 2014; 20:1695-709. [PMID: 25558173 PMCID: PMC4279588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Accepted: 12/18/2014] [Indexed: 11/16/2022] Open
Abstract
PURPOSE The goal of the present study was to test for the first time whether glaucomatous-like disease progression in a mouse can be assessed morphologically and functionally with spectral domain optical coherence tomography (SD-OCT). METHODS We monitored progressive changes in conventional outflow tissues of living mice overexpressing human bone morphogenetic protein 2 (BMP2), a model for glaucoma. Intraocular pressure (IOP) and outflow tissue morphology/Young's modulus were followed in mice for 36 days with rebound tonometry and SD-OCT, respectively. Results were compared to standard histological methods. Outflow facility was calculated from flow measurements with direct cannulation of anterior chambers subjected to three sequential pressure steps. RESULTS Overexpression of BMP2 significantly elevated IOP in a biphasic manner over time compared to mice that overexpressed green fluorescent protein in outflow cells and naïve controls. SD-OCT revealed changes in outflow tissues overexpressing BMP2 that corresponded with the timing of the IOP phases and decreased outflow facility. In the first phase, the angle was open, but the trabecular meshwork and the cornea were thickened. OCT detected increased trabecular meshwork stiffness after provocative IOP challenges of the BMP2 eyes, which corresponded to increased collagen deposition with transmission electron microscopy. In contrast, the angle was closed in the second phase. IOP elevation over 36 days due to BMP2 overexpression resulted in significant retinal ganglion cell and axon loss. CONCLUSIONS Although not a feasible open-angle glaucoma model, the BMP2 mice were useful for demonstrating the utility of SD-OCT in following disease progression and differentiating between two forms of ocular pathology over time that resulted in ocular hypertension.
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Affiliation(s)
- Guorong Li
- Department of Ophthalmology, Duke University, Durham, NC
| | - Sina Farsiu
- Department of Ophthalmology, Duke University, Durham, NC,Department of Biomedical Engineering, Duke University, Durham, NC
| | - Jianming Qiu
- Department of Ophthalmology, Duke University, Durham, NC
| | - Angela Dixon
- Department of Ophthalmology, Duke University, Durham, NC
| | - Chunwei Song
- School of Astronautics, Harbin Institute of Technology, Harbin, China
| | - Stuart J. McKinnon
- Department of Ophthalmology, Duke University, Durham, NC,Department of Neurobiology, Duke University, Durham, NC
| | - Fan Yuan
- Department of Biomedical Engineering, Duke University, Durham, NC
| | - Pedro Gonzalez
- Department of Ophthalmology, Duke University, Durham, NC
| | - W. Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, NC,Department of Biomedical Engineering, Duke University, Durham, NC
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Han H, Kursula P. The olfactomedin domain from gliomedin is a β-propeller with unique structural properties. J Biol Chem 2014; 290:3612-21. [PMID: 25525261 DOI: 10.1074/jbc.m114.627547] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
All members of the olfactomedin (OLF) family have a conserved extracellular OLF domain, for which a structure has not been available. We present here the crystal structure of the OLF domain from gliomedin. Gliomedin is a protein expressed by Schwann cells in peripheral nerves, important for the formation of the nodes of Ranvier. Gliomedin interacts with neuronal cell adhesion molecules, such as neurofascin, but the structural details of the interaction are not known. The structure of the OLF domain presents a five-bladed β-propeller fold with unusual geometric properties. The symmetry of the structure is not 5-fold, but rather reveals a twisted arrangement. The conserved top face of the gliomedin OLF domain is likely to be important for binding to neuronal ligands. Our results provide a structural basis for the functions of gliomedin in Schwann cells, enable the understanding of the role of the gliomedin OLF domain in autoimmune neuropathies, and unravel the locations of human disease-causing mutations in other OLF family members, including myocilin.
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Affiliation(s)
- Huijong Han
- From the Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, 90014 Oulu, Finland, the German Electron Synchrotron (DESY), 22607 Hamburg, Germany, and
| | - Petri Kursula
- From the Faculty of Biochemistry and Molecular Medicine and Biocenter Oulu, University of Oulu, 90014 Oulu, Finland, the German Electron Synchrotron (DESY), 22607 Hamburg, Germany, and the Department of Biomedicine, University of Bergen, N-5020 Bergen, Norway
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Danielewska ME, Krzyżanowska-Berkowska P, Iskander DR. Glaucomatous and age-related changes in corneal pulsation shape. The ocular dicrotism. PLoS One 2014; 9:e102814. [PMID: 25032962 PMCID: PMC4102586 DOI: 10.1371/journal.pone.0102814] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Accepted: 06/22/2014] [Indexed: 12/04/2022] Open
Abstract
PURPOSE To ascertain whether the incidence of ocular dicrotic pulse (ODP) increases with age, it is more pronounced in glaucomatous than in normal eyes and whether it is related to cardiovascular activity. METHODS 261 subjects aged 47 to 78 years were included in the study and classified into four groups: primary open angle glaucoma (POAG), primary angle-closure glaucoma (PACG), glaucoma suspects with glaucomatous optic disc appearance (GODA) and the controls (CG). Additionally, in each group, subjects with ODP were divided into two age subgroups around the median age. A non-contact ultrasonic method was used to measure corneal indentation pulse (CIP) synchronically with the acquisition of electrocardiography (ECG) and blood pulse signals. ODP was assessed from the acquired signals that were numerically processed in a custom written program. RESULTS ODP incidence was about 78%, 66%, 66% and 84% for CG, GODA, POAG, and PACG group, respectively. With advancing age, the ODP incidence increased for all subjects (Δ = 12%), the highest being for the PACG and POAG groups (Δ = 30%). GODA group did not show an age-related increase in the incidence of ODP. CONCLUSIONS The ocular dicrotism, measured with non-contact ultrasonic method, was found to be a common phenomenon in elderly subjects. The increased ODP incidence in PACG and POAG group may correspond to either higher stiffness of glaucoma eyes, biochemical abnormalities in eye tissues, changes in ocular hemodynamics, may reflect the effect of medications or be a combination of all those factors. The results of GODA group suggest different mechanisms governing their ocular pulse that makes them less susceptible to generating ODP and having decreased predisposition to glaucoma.
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Affiliation(s)
- Monika E. Danielewska
- Institute of Biomedical Engineering and Instrumentation, Wroclaw University of Technology, Wroclaw, Poland
| | | | - D. Robert Iskander
- Institute of Biomedical Engineering and Instrumentation, Wroclaw University of Technology, Wroclaw, Poland
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Stothert AR, Suntharalingam A, Huard DJE, Fontaine SN, Crowley VM, Mishra S, Blagg BSJ, Lieberman RL, Dickey CA. Exploiting the interaction between Grp94 and aggregated myocilin to treat glaucoma. Hum Mol Genet 2014; 23:6470-80. [PMID: 25027323 DOI: 10.1093/hmg/ddu367] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Gain-of-function mutations in the olfactomedin domain of the MYOC gene facilitate the toxic accumulation of amyloid-containing myocilin aggregates, hastening the onset of the prevalent ocular disorder primary open-angle glaucoma. Aggregation of wild-type myocilin has been reported in other glaucoma subtypes, suggesting broader relevance of misfolded myocilin across the disease spectrum, but the absence of myocilin does not cause disease. Thus, strategies aimed at eliminating myocilin could be therapeutically relevant for glaucoma. Here, a novel and selective Grp94 inhibitor reduced the levels of several mutant myocilin proteins as well as wild-type myocilin when forced to misfold in cells. This inhibitor rescued mutant myocilin toxicity in primary human trabecular meshwork cells. Mechanistically, in vitro kinetics studies demonstrate that Grp94 recognizes on-pathway aggregates of the myocilin olfactomedin domain (myoc-OLF), accelerates rates of aggregation and co-precipitates with myoc-OLF. These results indicate that aberrant myocilin quaternary structure drives Grp94 recognition, rather than peptide motifs exposed by unfolded protein. Inhibition of Grp94 ameliorates the effects of Grp94-accelerated myoc-OLF aggregation, and Grp94 remains in solution. In cells, when wild-type myocilin is driven to misfold and aggregate, it becomes a client of Grp94 and sensitive to Grp94 inhibition. Taken together, the interaction of Grp94 with myocilin aggregates can be manipulated by cellular environment and genetics; this process can be exploited with Grp94 inhibitors to promote the clearance of toxic forms of myocilin.
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Affiliation(s)
- Andrew R Stothert
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA
| | - Amirthaa Suntharalingam
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA
| | - Dustin J E Huard
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA and
| | - Sarah N Fontaine
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA
| | - Vincent M Crowley
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66049, USA
| | - Sanket Mishra
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66049, USA
| | - Brian S J Blagg
- Department of Medicinal Chemistry, University of Kansas, Lawrence, KS 66049, USA
| | - Raquel L Lieberman
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA and
| | - Chad A Dickey
- Department of Molecular Medicine and Byrd Alzheimer's Research Institute, University of South Florida, Tampa, FL 33613, USA,
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Swaminathan SS, Oh DJ, Kang MH, Shepard AR, Pang IH, Rhee DJ. TGF-β2-mediated ocular hypertension is attenuated in SPARC-null mice. Invest Ophthalmol Vis Sci 2014; 55:4084-97. [PMID: 24906856 DOI: 10.1167/iovs.13-12463] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
PURPOSE Transforming growth factor-β2 (TGF-β2) has been implicated in the pathogenesis of primary open-angle glaucoma through extracellular matrix (ECM) alteration among various mechanisms. Secreted protein acidic and rich in cysteine (SPARC) is a matricellular protein that regulates ECM within the trabecular meshwork (TM), and is highly upregulated by TGF-β2. We hypothesized that, in vivo, SPARC is a critical regulatory node in TGF-β2-mediated ocular hypertension. METHODS Empty (Ad.empty) or TGF-β2-containing adenovirus (Ad.TGF-β2) was injected intravitreally into C57BL6-SV129 WT and SPARC-null mice. An initial study was performed to identify a stable period for IOP measurement under isoflurane. The IOP was measured before injection and every other day for two weeks using rebound tonometry. Additional mice were euthanized at peak IOP for immunohistochemistry. RESULTS The IOP was stable under isoflurane during minutes 5 to 8. The IOP was significantly elevated in Ad.TGF-β2-injected (n = 8) versus Ad.empty-injected WT (n = 8) mice and contralateral uninjected eyes during days 4 to 11 (P < 0.03). The IOPs were not significantly elevated in Ad.TGF-β2-injected versus Ad.empty-injected SPARC-null mice. However, on day 8, the IOP of Ad.TGF-β2-injected SPARC-null eyes was elevated compared to that of contralateral uninjected eyes (P = 0.0385). Immunohistochemistry demonstrated that TGF-β2 stimulated increases in collagen IV, fibronectin, plasminogen activator inhibitor-1 (PAI-1), connective tissue growth factor (CTGF), and SPARC in WT mice, but only PAI-1 and CTGF in SPARC-null mice (P < 0.05). CONCLUSIONS SPARC is essential to the regulation of TGF-β2-mediated ocular hypertension. Deletion of SPARC significantly attenuates the effects of TGF-β2 by restricting collagen IV and fibronectin expression. These data provide further evidence that SPARC may have an important role in IOP regulation and possibly glaucoma pathogenesis.
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Affiliation(s)
- Swarup S Swaminathan
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Dong-Jin Oh
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Min Hyung Kang
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
| | - Allan R Shepard
- Ophthalmology Research/Glaucoma Research, Novartis Institutes for Biomedical Research, Fort Worth, Texas, United States
| | - Iok-Hou Pang
- Department of Pharmaceutical Sciences and North Texas Eye Research Institute, University of North Texas Health Sciences Center, Fort Worth, Texas, United States
| | - Douglas J Rhee
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, United States
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Janssen SF, Gorgels TG, Ramdas WD, Klaver CC, van Duijn CM, Jansonius NM, Bergen AA. The vast complexity of primary open angle glaucoma: Disease genes, risks, molecular mechanisms and pathobiology. Prog Retin Eye Res 2013; 37:31-67. [DOI: 10.1016/j.preteyeres.2013.09.001] [Citation(s) in RCA: 131] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Revised: 07/26/2013] [Accepted: 09/03/2013] [Indexed: 12/21/2022]
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McDowell CM, Tebow HE, Wordinger RJ, Clark AF. Smad3 is necessary for transforming growth factor-beta2 induced ocular hypertension in mice. Exp Eye Res 2013; 116:419-23. [PMID: 24184030 DOI: 10.1016/j.exer.2013.10.017] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 10/21/2013] [Accepted: 10/23/2013] [Indexed: 11/19/2022]
Abstract
TGFβ2 induces extracellular matrix (ECM) remodeling and alters the cytoskeleton by both the canonical Smad and non-canonical signaling pathways. TGFβ2 regulates the expression of ECM proteins in trabecular meshwork (TM) cells, increases intraocular pressure (IOP) in an ex vivo perfusion organ culture model, and induces ocular hypertension in rodent eyes. A necessary step in the canonical Smad signaling pathway is phosphorylation of receptor protein Smad3 by the TGF-β receptor complex. The purpose of this study was to determine whether TGFβ2 signals in vivo through the canonical Smad signaling pathway in the TM using Smad3 knockout (KO) mice. Ad5.hTGFβ2(226/228) (2.5 × 10(7) pfu) was injected intravitreally into one eye of homozygous (WT), heterozygous (HET), and homozygous (KO) 129-Smad3(tm1Par)/J mice (n = 9-10 mice/group), with the uninjected contralateral eye serving as the control. IOP measurements were taken using a rebound tonometer. To test the effect of TGFβ2 signaling on the ECM, fibronectin expression was determined by immunohistochemistry and qPCR analysis. Transduction of the TM with viral vector Ad5.hTGFβ2(226/228) caused a statistically significant difference in IOP exposure between Smad3 genotypes: WT, 187.7 ± 23.9 mmHg*day (n = 9); HET, 95.6 ± 24.5 mmHg*day (n = 9); KO, 52.8 ± 25.2 mmHg*day (n = 10); (p < 0.05 WT versus HET, p < 0.01 WT versus KO). Immunohistochemistry and qPCR analysis showed that Ad5.hTGFβ2(226/228) increased fibronectin expression in the TM of WT mice (2.23 ± 0.24 fold) compared to Smad3 KO mice (0.99 ± 0.19 fold), p < 0.05. These results demonstrate Smad3 is a necessary signaling protein for TGFβ2-induced ocular hypertension and fibronectin deposition in the TM.
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Affiliation(s)
- Colleen M McDowell
- North Texas Eye Research Institute, Department of Cell Biology and Anatomy, University of North Texas Health Science Center, CBH-441, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, USA
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