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Murugan S, de Campos VS, Ghag SA, Ng M, Shyam R. Characterization of a Novel Mouse Model for Fuchs Endothelial Corneal Dystrophy. Invest Ophthalmol Vis Sci 2024; 65:18. [PMID: 38587441 PMCID: PMC11005065 DOI: 10.1167/iovs.65.4.18] [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: 10/09/2023] [Accepted: 03/23/2024] [Indexed: 04/09/2024] Open
Abstract
Purpose Fuchs endothelial corneal dystrophy (FECD) is a progressive blinding disorder, characterized by increased corneal endothelial excrescences (guttae), corneal endothelial cell loss, and edema. These symptoms are hypothesized to be caused by changes in the extracellular matrix (ECM) and mitochondrial dysfunction in the corneal endothelium. Despite this clinical and biological relevance, a comprehensive animal model that recapitulates all the major disease characteristics is currently unavailable. In this study, we develop such a model to improve our understanding of the signaling pathways involved in the FECD progression and develop strategies for early intervention. Method To generate a comprehensive FECD model, we generated a double mutant mouse bearing tamoxifen-inducible knockdown of Slc4a11 and the Col8a2 (Q455K) mutation. We performed optical coherence tomography (OCT) and in vivo confocal microscopy using the Heidelberg Retinal Tomography 3 - Rostock Cornea module (HRT3-RCM) on the mice at 5 weeks of age before tamoxifen feeding to establish baseline values for corneal thickness, endothelial cell density, and test for the presence of guttae. We measured these parameters again post-tamoxifen treatment at 16 weeks of age. We collected corneas at 16 weeks to perform histopathology, immunofluorescence staining for tight junctions, adherens junctions, and oxidative stress. We evaluated endothelial pump function using a lactate assay. Results The double mutant tamoxifen-fed animals showed the presence of guttae, and displayed increased corneal thickness and decreased endothelial cell density. Endothelial cells showed altered morphology with disrupted adherens junctions and elevated reactive oxygen species (ROS). Finally, we found that stromal lactate concentrations were elevated in the double mutant mice, indicative of compromised endothelial pump function. Conclusions Overall, this mouse model recapitulates all the important phenotypic features associated with FECD.
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Affiliation(s)
- Subashree Murugan
- Vision Science Program, School of Optometry, Indiana University Bloomington, Indiana, United States
| | - Viviane Souza de Campos
- Vision Science Program, School of Optometry, Indiana University Bloomington, Indiana, United States
| | - Sachin Anil Ghag
- Vision Science Program, School of Optometry, Indiana University Bloomington, Indiana, United States
| | - Matthew Ng
- Department of Biology, Indiana University Bloomington, Indiana, United States
| | - Rajalekshmy Shyam
- Vision Science Program, School of Optometry, Indiana University Bloomington, Indiana, United States
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Thomasy SM, Leonard BC, Greiner MA, Skeie JM, Raghunathan VK. Squishy matters - Corneal mechanobiology in health and disease. Prog Retin Eye Res 2024; 99:101234. [PMID: 38176611 DOI: 10.1016/j.preteyeres.2023.101234] [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: 09/01/2023] [Revised: 12/22/2023] [Accepted: 12/27/2023] [Indexed: 01/06/2024]
Abstract
The cornea, as a dynamic and responsive tissue, constantly interacts with mechanical forces in order to maintain its structural integrity, barrier function, transparency and refractive power. Cells within the cornea sense and respond to various mechanical forces that fundamentally regulate their morphology and fate in development, homeostasis and pathophysiology. Corneal cells also dynamically regulate their extracellular matrix (ECM) with ensuing cell-ECM crosstalk as the matrix serves as a dynamic signaling reservoir providing biophysical and biochemical cues to corneal cells. Here we provide an overview of mechanotransduction signaling pathways then delve into the recent advances in corneal mechanobiology, focusing on the interplay between mechanical forces and responses of the corneal epithelial, stromal, and endothelial cells. We also identify species-specific differences in corneal biomechanics and mechanotransduction to facilitate identification of optimal animal models to study corneal wound healing, disease, and novel therapeutic interventions. Finally, we identify key knowledge gaps and therapeutic opportunities in corneal mechanobiology that are pressing for the research community to address especially pertinent within the domains of limbal stem cell deficiency, keratoconus and Fuchs' endothelial corneal dystrophy. By furthering our understanding corneal mechanobiology, we can contextualize discoveries regarding corneal diseases as well as innovative treatments for them.
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Affiliation(s)
- Sara M Thomasy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California - Davis, Davis, CA, United States; Department of Ophthalmology & Vision Science, School of Medicine, University of California - Davis, Davis, CA, United States; California National Primate Research Center, Davis, CA, United States.
| | - Brian C Leonard
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California - Davis, Davis, CA, United States; Department of Ophthalmology & Vision Science, School of Medicine, University of California - Davis, Davis, CA, United States
| | - Mark A Greiner
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, United States; Iowa Lions Eye Bank, Coralville, IA, United States
| | - Jessica M Skeie
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, United States; Iowa Lions Eye Bank, Coralville, IA, United States
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Wu Y, Shi R, Chen H, Zhang Z, Bao S, Qu J, Zhou M. Effect of the gut microbiome in glaucoma risk from the causal perspective. BMJ Open Ophthalmol 2024; 9:e001547. [PMID: 38286567 PMCID: PMC10826588 DOI: 10.1136/bmjophth-2023-001547] [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: 10/25/2023] [Accepted: 01/12/2024] [Indexed: 01/31/2024] Open
Abstract
OBJECTIVE Evidence from observational studies has reported possible associations between the gut microbiome (GM) and glaucoma. However, the causal effect of GM on glaucoma risk remains to be determined. METHODS AND ANALYSIS We conducted two-sample bidirectional Mendelian randomisation (MR) analyses to explore the causal association between GM and glaucoma. Genome-wide association study summary statistics of 196 GM taxa (n=18 340) and glaucoma (18 902 cases and 358 375 controls) were obtained from MiBioGen and FinnGen Consortium. Inverse variance weighted, MR-Egger, weighted median, weighted mode, Mendelian Randomisation Pleiotropy Residual Sum and Outlier, MR-Egger intercept and Cochran's Q statistical analyses were used to supplement MR results and sensitivity analysis. An independent cohort from the Medical Research Council (MRC) Integrative Epidemiology Unit at the University of Bristol (MRC-IEU) Consortium (1715 cases and 359 479 controls) was used to validate causal effects. RESULTS Results of the MR analysis suggested that the family Oxalobacteraceae (OR 0.900, 95% CI 0.843 to 0.961, p=0.002) and the genus Eggerthella (OR 0.881, 95% CI 0.811 to 0.957, p=0.003) had a negative effect on glaucoma, whereas the genus Bilophila (OR 1.202, 95% CI 1.074 to 1.346, p=0.001), LachnospiraceaeUCG010 (OR 1.256, 95% CI 1.109 to 1.423, p=0.0003) and Ruminiclostridium 9 (OR 1.258, 95% CI 1.083 to 1.461, p=0.003) had a positive effect on glaucoma. Among these, the positive causal effect of LachnospiraceaeUCG010 (OR 1.002, 95% CI 1.000 to 1.004, p=0.033) on glaucoma was replicated in an independent cohort. CONCLUSION This MR analysis from large population studies demonstrated the causal effect of GM on glaucoma risk and supported the role of GM in influencing glaucoma susceptibility.
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Affiliation(s)
- Yaxuan Wu
- School of Biomedical Engineering, School of Information and Communication Engineering, Hainan University, Haikou, People's Republic of China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, People's Republic of China
- Hainan Institute of Real World Data, Qionghai, People's Republic of China
| | - Ronghua Shi
- School of Biomedical Engineering, School of Information and Communication Engineering, Hainan University, Haikou, People's Republic of China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, People's Republic of China
- Hainan Institute of Real World Data, Qionghai, People's Republic of China
| | - He Chen
- School of Biomedical Engineering, School of Information and Communication Engineering, Hainan University, Haikou, People's Republic of China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, People's Republic of China
- Hainan Institute of Real World Data, Qionghai, People's Republic of China
| | - Zicheng Zhang
- School of Biomedical Engineering, School of Information and Communication Engineering, Hainan University, Haikou, People's Republic of China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, People's Republic of China
- Hainan Institute of Real World Data, Qionghai, People's Republic of China
| | - Siqi Bao
- School of Biomedical Engineering, School of Information and Communication Engineering, Hainan University, Haikou, People's Republic of China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, People's Republic of China
- Hainan Institute of Real World Data, Qionghai, People's Republic of China
| | - Jia Qu
- School of Biomedical Engineering, School of Information and Communication Engineering, Hainan University, Haikou, People's Republic of China
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, People's Republic of China
- Hainan Institute of Real World Data, Qionghai, People's Republic of China
| | - Meng Zhou
- National Clinical Research Center for Ocular Diseases, Eye Hospital, Wenzhou Medical University, Wenzhou, People's Republic of China
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Banerjee S, Lu S, Jain A, Wang I, Tao H, Srinivasan S, Nemeth E, He P. Targeting PKC alleviates iron overload in diabetes and hemochromatosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.28.569107. [PMID: 38076948 PMCID: PMC10705472 DOI: 10.1101/2023.11.28.569107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2024]
Abstract
Diabetes is one of the most prevalent chronic diseases worldwide. Iron overload increases the incidence of diabetes and aggravates diabetic complications that cause mortality. Reciprocally, diabetes potentially promotes body iron loading, but the mechanism remains not well understood. In this study, we demonstrated systemic iron excess and the upregulation of iron exporter ferroportin (Fpn) in the enterocytes and macrophages of multiple diabetic mouse models. Increased Fpn expression and iron efflux was also seen in the enterocytes of type 2 diabetic human patients. We further showed that protein kinase C (PKC), which is activated in hyperglycemia, was responsible for the sustained membrane expression of Fpn in physiological and in diabetic settings. For the first time, we identified that PKCs were novel binding proteins and positive regulators of Fpn. Mechanistically, hyperactive PKC promoted exocytotic membrane insertion while inhibited the endocytic trafficking of Fpn in the resting state. PKC also protected Fpn from internalization and degradation by its ligand hepcidin dependent on decreased ubiquitination and increased phosphorylation of Fpn. Importantly, the loss-of-function and pharmacological inhibition of PKC alleviated systemic iron overload in diabetes and hemochromatosis. Our study thus highlights PKC as a novel target in the control of systemic iron homeostasis.
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