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Rudzitis CN, Lakk M, Singh A, Redmon SN, Kirdajova D, Tseng YT, De Ieso ML, Stamer WD, Herberg S, Križaj D. TRPV4 overactivation enhances cellular contractility and drives ocular hypertension in TGFβ2 overexpressing eyes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.11.05.622187. [PMID: 39574569 PMCID: PMC11580928 DOI: 10.1101/2024.11.05.622187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2024]
Abstract
The risk for developing primary open-angle glaucoma (POAG) correlates with the magnitude of ocular hypertension (OHT) and the concentration of transforming growth factor-β2 (TGFβ2) in the aqueous humor. Effective treatment of POAG requires detailed understanding of interaction between pressure sensing mechanisms in the trabecular meshwork (TM) and biochemical risk factors. Here, we employed molecular, optical, electrophysiological and tonometric strategies to establish the role of TGFβ2 in transcription and functional expression of mechanosensitive channel isoforms alongside studies of TM contractility in biomimetic hydrogels, and intraocular pressure (IOP) regulation in a mouse model of TGFβ2 -induced OHT. TGFβ2 upregulated expression of TRPV4 and PIEZO1 transcripts and time-dependently augmented functional TRPV4 activation. TRPV4 activation induced TM contractility whereas pharmacological inhibition suppressed TGFβ2-induced hypercontractility and abrogated OHT in eyes overexpressing TGFβ2. Trpv4-deficient mice resisted TGFβ2-driven increases in IOP. Nocturnal OHT was not additive to TGFβ-evoked OHT. Our study establishes the fundamental role of TGFβ as a modulator of mechanosensing in nonexcitable cells, identifies TRPV4 channel as the final common mechanism for TM contractility and circadian and pathological OHT and offers insights future treatments that can lower IOP in the sizeable cohort of hypertensive glaucoma patients that resist current treatments.
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Affiliation(s)
- Christopher N. Rudzitis
- Department of Ophthalmology and Visual Sciences
- Department of Neurobiology, University of Utah, Salt Lake City, UT
| | - Monika Lakk
- Department of Ophthalmology and Visual Sciences
| | - Ayushi Singh
- Department of Ophthalmology and Visual Sciences
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY
| | | | | | | | - Michael L. De Ieso
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC
| | - W. Daniel Stamer
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, NC
| | - Samuel Herberg
- Department of Ophthalmology and Visual Sciences
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY
| | - David Križaj
- Department of Ophthalmology and Visual Sciences
- Department of Neurobiology, University of Utah, Salt Lake City, UT
- Department of Bioengineering, University of Utah, Salt Lake City, UT
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Choy DMY, Ang BCH, Adav SS, Zheng YB, Goh CJS, Wei J, Kumaran A, Chua CH, Gan NY, Sze SK, Yip LWL. Aqueous humour protein dysregulation in Asian eyes with primary open angle glaucoma. Exp Eye Res 2024; 243:109887. [PMID: 38609044 DOI: 10.1016/j.exer.2024.109887] [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: 01/07/2024] [Revised: 02/19/2024] [Accepted: 04/04/2024] [Indexed: 04/14/2024]
Abstract
The pathophysiology of Primary Open Angle Glaucoma (POAG) remains poorly understood. Through proteomic analysis of aqueous humour (AH) from POAG patients, we aim to identify changes in protein composition of these samples compared to control samples. High resolution mass spectrometry-based TMT6plex quantitative proteomics analysis is performed on AH samples collected from POAG patients, and compared against a control group of patients with cataracts. Data are available via ProteomeXchange with identifier PXD033153. 1589 proteins were quantified from the aqueous samples using Proteome Discoverer version 2.2 software. Among these proteins, 210 were identified as unique master proteins. The proteins which were up or down-regulated by ±3 fold-change were considered significant. Human neuroblastoma full-length cDNA clone CS0DD006YL02 was significantly upregulated in patients with severe POAG on >2 medications, while actin, cytoplasmic 1, V2-7 protein (fragment), immunoglobulin-like polypeptide 1 and phosphatidylethanolamine-binding protein 4 were only present in these patients with severe POAG on >2 medications. Beta-crystallin B1 and B2, Gamma-crystallin C, D and S were significantly downregulated in the severe POAG ≤2 glaucoma medications group. Beta-crystallin B2, Gamma-crystallin D and GCT-A9 light chain variable region (fragment) were significantly downregulated in the non-severe POAG group. Actin, cytoplasmic 1 was significantly upregulated in subjects with severe POAG who required more than 2 glaucoma medications. Crystallins (Beta-crystallin B1 and B2, Gamma-crystallin C, D and S) were significantly downregulated in subjects with severe POAG who required less than 2 glaucoma medications.
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Affiliation(s)
- Darren Mun Yoong Choy
- Department of Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, 11 Jalan Tan Tock Seng, 308433, Singapore
| | - Bryan Chin Hou Ang
- Department of Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, 11 Jalan Tan Tock Seng, 308433, Singapore; Department of Ophthalmology, Woodlands Health, National Healthcare Group Eye Institute, Singapore; Department of Ophthalmology, Mayo Clinic, Jacksonville, USA
| | - Sunil S Adav
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Yu Bo Zheng
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Caius Jun Shyan Goh
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Jin Wei
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore
| | - Arjunan Kumaran
- Department of Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, 11 Jalan Tan Tock Seng, 308433, Singapore
| | - Chun Hau Chua
- Department of Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, 11 Jalan Tan Tock Seng, 308433, Singapore
| | - Nicola Yian Gan
- Department of Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, 11 Jalan Tan Tock Seng, 308433, Singapore
| | - Siu Kwan Sze
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, 637551, Singapore; Department of Health Sciences, Faculty of Applied Health Sciences, Brock University, St. Catharines, ON, Canada
| | - Leonard Wei Leon Yip
- Department of Ophthalmology, Tan Tock Seng Hospital, National Healthcare Group Eye Institute, 11 Jalan Tan Tock Seng, 308433, Singapore; Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
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Benagiano V, Rizzi A, Sannace C, Alessio G, Ribatti D, Dammacco R. Aqueous humor as eye lymph: A crossroad between venous and lymphatic system. Exp Eye Res 2024; 243:109904. [PMID: 38642600 DOI: 10.1016/j.exer.2024.109904] [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: 12/15/2023] [Revised: 03/18/2024] [Accepted: 04/17/2024] [Indexed: 04/22/2024]
Abstract
Aqueous humor (AQH) is a transparent fluid with characteristics similar to those of the interstitial fluid, which fills the eyeball posterior and anterior chambers and circulates in them from the sites of production to those of drainage. The AQH volume and pressure homeostasis is essential for the trophism of the ocular avascular tissues and their normal structure and function. Different AQH outflow pathways exist, including a main pathway, quite well defined anatomically and referred to as the conventional pathway, and some accessory pathways, more recently described and still not fully morphofunctionally understood, generically referred to as unconventional pathways. The conventional pathway is based on the existence of a series of conduits starting with the trabecular meshwork and Schlemm's Canal and continuing with a system of intrascleral and episcleral venules, which are tributaries to veins of the anterior segment of the eyeball. The unconventional pathways are mainly represented by the uveoscleral pathway, in which AQH flows through clefts, interstitial conduits located in the ciliary body and sclera, and then merges into the aforementioned intrascleral and episcleral venules. A further unconventional pathway, the lymphatic pathway, has been supported by the demonstration of lymphatic microvessels in the limbal sclera and, possibly, in the uvea (ciliary body, choroid) as well as by the ocular glymphatic channels, present in the neural retina and optic nerve. It follows that AQH may be drained from the eyeball through blood vessels (TM-SC pathway, US pathway) or lymphatic vessels (lymphatic pathway), and the different pathways may integrate or compensate for each other, optimizing the AQH drainage. The present review aims to define the state-of-the-art concerning the structural organization and the functional anatomy of all the AQH outflow pathways. Particular attention is paid to examining the regulatory mechanisms active in each of them. The new data on the anatomy and physiology of AQH outflow pathways is the key to understanding the pathophysiology of AQH outflow disorders and could open the way for novel approaches to their treatment.
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Affiliation(s)
- Vincenzo Benagiano
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy.
| | - Anna Rizzi
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
| | - Carmela Sannace
- Azienda Sanitaria Locale Bari, Ophthalmology Day Service Triggiano-Gioia del Colle, Bari, Italy
| | - Giovanni Alessio
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
| | - Domenico Ribatti
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
| | - Rosanna Dammacco
- Department of Translational Biomedicine and Neuroscience, University of Bari 'Aldo Moro', Bari, Italy
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Ouyang J, Sun W, Shen H, Liu X, Wu Y, Jiang H, Li X, Wang Y, Jiang Y, Li S, Xiao X, Hejtmancik JF, Tan Z, Zhang Q. Truncation mutations in MYRF underlie primary angle closure glaucoma. Hum Genet 2023; 142:103-123. [PMID: 36129575 PMCID: PMC12017149 DOI: 10.1007/s00439-022-02487-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 09/05/2022] [Indexed: 01/18/2023]
Abstract
Mutations in myelin regulatory factor (MYRF), a gene mapped to 11q12-q13.3, are responsible for autosomal dominant high hyperopia and seem to be associated with angle closure glaucoma, which is one of the leading causes of irreversible blindness worldwide. Whether there is a causal link from the MYRF mutations to the pathogenesis of primary angle-closure glaucoma (PACG) remains unclear at this time. Six truncation mutations, including five novel and one previously reported, in MYRF are identified in seven new probands with hyperopia, of whom all six adults have glaucoma, further confirming the association of MYRF mutations with PACG. Immunofluorescence microscopy demonstrates enriched expression of MYRF in the ciliary body and ganglion cell layer in humans and mice. Myrfmut/+ mice have elevated IOP and fewer ganglion cells along with thinner retinal nerve fiber layer with ganglion cell layer than wild-type. Transcriptome sequencing of Myrfmut/+ retinas shows downregulation of Dnmt3a, a gene previously associated with PACG. Co-immunoprecipitation demonstrates a physical association of DNMT3A with MYRF. DNA methylation sequencing identifies several glaucoma-related cell events in Myrfmut/+ retinas. The interaction between MYRF and DNMT3A underlies MYRF-associated PACG and provides clues for pursuing further investigation into the pathogenesis of PACG and therapeutic target.
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Affiliation(s)
- Jiamin Ouyang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China
| | - Huangxuan Shen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China
| | - Xing Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China
| | - Yingchen Wu
- Department of Gynecology and Obstetrics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, China
| | - Hongmei Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China
| | - Xueqing Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China
| | - Yingwei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China
| | - Yi Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China
| | - J Fielding Hejtmancik
- Molecular Ophthalmic Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, Rockville, MD, 20852, USA.
| | - Zhiqun Tan
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA.
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, 54 Xianlie Road, Guangzhou, 510060, China.
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Du R, Li D, Zhu M, Zheng L, Ren K, Han D, Li L, Ji J, Fan Y. Cell senescence alters responses of porcine trabecular meshwork cells to shear stress. Front Cell Dev Biol 2022; 10:1083130. [PMID: 36478743 PMCID: PMC9721263 DOI: 10.3389/fcell.2022.1083130] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Accepted: 11/04/2022] [Indexed: 10/05/2024] Open
Abstract
Mechanical microenvironment and cellular senescence of trabecular meshwork cells (TMCs) are suspected to play a vital role in primary open-angle glaucoma pathogenesis. However, central questions remain about the effect of shear stress on TMCs and how aging affects this process. We have investigated the effect of shear stress on the biomechanical properties and extracellular matrix regulation of normal and senescent TMCs. We found a more significant promotion of Fctin formation, a more obvious realignment of F-actin fibers, and a more remarkable increase in the stiffness of normal cells in response to the shear stress, in comparison with that of senescent cells. Further, as compared to normal cells, senescent cells show a reduced extracellular matrix turnover after shear stress stimulation, which might be attributed to the different phosphorylation levels of the extracellular signal-regulated kinase. Our results suggest that TMCs are able to sense and respond to the shear stress and cellular senescence undermines the mechanobiological response, which may lead to progressive failure of cellular TM function with age.
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Affiliation(s)
- Ruotian Du
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Dongyan Li
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Meng Zhu
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Lisha Zheng
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Keli Ren
- Lab for Biological Imaging and Nanomedicine, National Center for Nanoscience and Technology, Beijing, China
| | - Dong Han
- Lab for Biological Imaging and Nanomedicine, National Center for Nanoscience and Technology, Beijing, China
| | - Long Li
- State Key Laboratory of Nonlinear Mechanics and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China
| | - Jing Ji
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
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Li H, Singh A, Perkumas KM, Stamer WD, Ganapathy PS, Herberg S. YAP/TAZ Mediate TGFβ2-Induced Schlemm's Canal Cell Dysfunction. Invest Ophthalmol Vis Sci 2022; 63:15. [PMID: 36350617 PMCID: PMC9652721 DOI: 10.1167/iovs.63.12.15] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 10/18/2022] [Indexed: 11/11/2022] Open
Abstract
Purpose Elevated transforming growth factor beta2 (TGFβ2) levels in the aqueous humor have been linked to glaucomatous outflow tissue dysfunction. Potential mediators of dysfunction are the transcriptional coactivators, Yes-associated protein (YAP) and transcriptional coactivator with PDZ binding motif (TAZ). However, the molecular underpinnings of YAP/TAZ modulation in Schlemm's canal (SC) cells under glaucomatous conditions are not well understood. Here, we investigate how TGFβ2 regulates YAP/TAZ activity in human SC (HSC) cells using biomimetic extracellular matrix hydrogels, and examine whether pharmacological YAP/TAZ inhibition would attenuate TGFβ2-induced HSC cell dysfunction. Methods Primary HSC cells were seeded atop photo-cross-linked extracellular matrix hydrogels, made of collagen type I, elastin-like polypeptide and hyaluronic acid, or encapsulated within the hydrogels. HSC cells were induced with TGFβ2 in the absence or presence of concurrent actin destabilization or pharmacological YAP/TAZ inhibition. Changes in actin cytoskeletal organization, YAP/TAZ activity, extracellular matrix production, phospho-myosin light chain levels, and hydrogel contraction were assessed. Results TGFβ2 significantly increased YAP/TAZ nuclear localization in HSC cells, which was prevented by either filamentous-actin relaxation or depolymerization. Pharmacological YAP/TAZ inhibition using verteporfin without light stimulation decreased fibronectin expression and actomyosin cytoskeletal rearrangement in HSC cells induced by TGFβ2. Similarly, verteporfin significantly attenuated TGFβ2-induced HSC cell-encapsulated hydrogel contraction. Conclusions Our data provide evidence for a pathologic role of aberrant YAP/TAZ signaling in HSC cells under simulated glaucomatous conditions and suggest that pharmacological YAP/TAZ inhibition has promising potential to improve outflow tissue dysfunction.
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Affiliation(s)
- Haiyan Li
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, United States
| | - Ayushi Singh
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, United States
| | - Kristin M. Perkumas
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, North Carolina, United States
| | - W. Daniel Stamer
- Department of Ophthalmology, Duke Eye Center, Duke University, Durham, North Carolina, United States
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States
| | - Preethi S. Ganapathy
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, New York, United States
- BioInspired Institute, Syracuse University, Syracuse, New York, United States
| | - Samuel Herberg
- Department of Ophthalmology and Visual Sciences, SUNY Upstate Medical University, Syracuse, New York, United States
- Department of Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, New York, United States
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, New York, United States
- BioInspired Institute, Syracuse University, Syracuse, New York, United States
- Department of Biomedical and Chemical Engineering, Syracuse University, Syracuse, New York, United States
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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: 17] [Impact Index Per Article: 5.7] [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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8
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Chan D, Won GJ, Read AT, Ethier CR, Thackaberry E, Crowell SR, Booler H, Bantseev V, Sivak JM. Application of an organotypic ocular perfusion model to assess intravitreal drug distribution in human and animal eyes. J R Soc Interface 2022; 19:20210734. [PMID: 35078337 PMCID: PMC8790337 DOI: 10.1098/rsif.2021.0734] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Intravitreal (ITV) drug delivery is a new cornerstone for retinal therapeutics. Yet, predicting the disposition of formulations in the human eye remains a major translational hurdle. A prominent, but poorly understood, issue in pre-clinical ITV toxicity studies is unintended particle movements to the anterior chamber (AC). These particles can accumulate in the AC to dangerously raise intraocular pressure. Yet, anatomical differences, and the inability to obtain equivalent human data, make investigating this issue extremely challenging. We have developed an organotypic perfusion strategy to re-establish intraocular fluid flow, while maintaining homeostatic pressure and pH. Here, we used this approach with suitably sized microbeads to profile anterior and posterior ITV particle movements in live versus perfused porcine eyes, and in human donor eyes. Small-molecule suspensions were then tested with the system after exhibiting differing behaviours in vivo. Aggregate particle size is supported as an important determinant of particle movements in the human eye, and we note these data are consistent with a poroelastic model of bidirectional vitreous transport. Together, this approach uses ocular fluid dynamics to permit, to our knowledge, the first direct comparisons between particle behaviours from human ITV injections and animal models, with potential to speed pre-clinical development of retinal therapeutics.
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Affiliation(s)
- D. Chan
- Donald K Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - G. J. Won
- Donald K Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - A. T. Read
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, USA
| | - C. R. Ethier
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, Georgia, USA
| | - E. Thackaberry
- Safety Assessment, Genentech Inc., San Francisco, CA, USA
| | - S. R. Crowell
- Preclinical and Translational Pharmacokinetics and Pharmacodynamics (PTPK) Genentech Inc., San Francisco, CA, USA
| | - H. Booler
- Safety Assessment, Genentech Inc., San Francisco, CA, USA
| | - V. Bantseev
- Safety Assessment, Genentech Inc., San Francisco, CA, USA
| | - J. M. Sivak
- Donald K Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada,Department of Ophthalmology and Vision Science, University of Toronto, Toronto, Ontario, Canada,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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9
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Chen L, Li M, Luo Z, Yan X, Yao K, Zhao Y, Zhang H. VIP Regulates Morphology and F-Actin Distribution of Schlemm's Canal in a Chronic Intraocular Pressure Hypertension Model via the VPAC2 Receptor. Invest Ophthalmol Vis Sci 2019; 59:2848-2860. [PMID: 30025111 DOI: 10.1167/iovs.17-22688] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the roles of vasoactive intestinal peptides (VIPs) in regulating the morphology and F-actin distribution of Schlemm's canal (SC) of rat eyes. Methods Chronic intraocular pressure (IOP) hypertension models with episcleral venous cauterization (EVC) were treated with topical VIP or PG99-465 (vasoactive intestinal peptide receptors 2 [VPAC2] antagonist). IOPs were measured with Tono-Pen, and the SC parameters, including the cross-section area, circumference, and length, were statistically evaluated by hematoxylin-eosin and CD31 immunohistochemical staining. Immunofluorescence was performed to detect the distribution of F-actin in the SC. Moreover, the distribution of filamentous actin (F-actin) and globular actin (G-actin) in human umbilical vein endothelial cells (HUVECs) was studied under a pressure system by immunofluorescence and Western blotting. Results Increased expressions of VIP and VPAC2 receptors, as well as a disordered distribution of F-actin were found in SC endothelial cells (SCEs) in the EVC model. Moreover, topical VIP maintained the normal distribution of F-actin in SCEs, expanded the collapsed SC, and induced a significant decrease in IOP in the EVC model. In in vitro HUVECs, the F-actin/G-actin ratio increased significantly under stress stimulation for 30 minutes. A total of 50 μM VIP helped maintain the normal F-actin/G-actin ratio of HUVECs against stress stimulation. Conclusions VIP regulates the distribution of F-actin in SCEs via the VPAC2 receptor in order to induce a decrease in IOP. VIP may represent a new target for antiglaucoma drugs.
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Affiliation(s)
- Liwen Chen
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Mu Li
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Zhaoxia Luo
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Xiaoqin Yan
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Ke Yao
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Yin Zhao
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
| | - Hong Zhang
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People's Republic of China
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10
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Tsukamoto T, Kajiwara K, Nada S, Okada M. Src mediates TGF‐β‐induced intraocular pressure elevation in glaucoma. J Cell Physiol 2018; 234:1730-1744. [DOI: 10.1002/jcp.27044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 06/25/2018] [Indexed: 12/20/2022]
Affiliation(s)
- Teruhisa Tsukamoto
- Department of Oncogene Research Research Institute for Microbial Diseases, Osaka University Osaka Japan
- New Drug Research Division Ako Research Institute, Otsuka Pharmaceutical Co., Ltd. Ako Japan
| | - Kentaro Kajiwara
- Department of Oncogene Research Research Institute for Microbial Diseases, Osaka University Osaka Japan
| | - Shigeyuki Nada
- Department of Oncogene Research Research Institute for Microbial Diseases, Osaka University Osaka Japan
| | - Masato Okada
- Department of Oncogene Research Research Institute for Microbial Diseases, Osaka University Osaka Japan
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11
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Montecchi-Palmer M, Bermudez JY, Webber HC, Patel GC, Clark AF, Mao W. TGFβ2 Induces the Formation of Cross-Linked Actin Networks (CLANs) in Human Trabecular Meshwork Cells Through the Smad and Non-Smad Dependent Pathways. Invest Ophthalmol Vis Sci 2017; 58:1288-1295. [PMID: 28241317 PMCID: PMC5341625 DOI: 10.1167/iovs.16-19672] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Purpose Increased intraocular pressure results from increased aqueous humor (AH) outflow resistance at the trabecular meshwork (TM) due to pathologic changes including the formation of cross-linked actin networks (CLANs). Transforming growth factor β2 (TGFβ2) is elevated in the AH and TM of primary open angle glaucoma (POAG) patients and induces POAG-associated TM changes, including CLANs. We determined the role of individual TGFβ2 signaling pathways in CLAN formation. Methods Cultured nonglaucomatous human TM (NTM) cells were treated with control or TGFβ2, with or without the inhibitors of TGFβ receptor, Smad3, c-Jun N-terminal kinases (JNK), extracellular signal regulated kinase (ERK), P38, or Rho-associated protein kinase (ROCK). NTM cells were cotreated with TGFβ2 plus inhibitors for 10 days or pretreated with TGFβ2 for 10 days followed by 1-hour inhibitor treatment. NTM cells were immunostained with phalloidin-Alexa-488 and 4',6-diamidino-2-phenylindole (DAPI). Data were analyzed using 1-way ANOVA and Dunnett's post hoc test. Results TGFβ2 significantly induced CLAN formation (n = 6 to 12, P < 0.05), which was completely inhibited by TGFβ receptor, Smad3, and ERK inhibitors, as well as completely or partially inhibited by JNK, P38, and ROCK inhibitors, depending on cell strains. One-hour exposure to ROCK inhibitor completely resolved formed CLANs (P < 0.05), whereas TGFβ receptor, Smad3 inhibitor, and ERK inhibitors resulted in partial or complete resolution. The JNK and P38 inhibitors showed partial or no resolution. Among these inhibitors, the ROCK inhibitor was the most disruptive to the actin stress fibers, whereas ERK inhibition showed the least disruption. Conclusions TGFβ2-induced CLANs in NTM cells were prevented and resolved using various pathway inhibitors. Apart from CLAN inhibition, some of these inhibitors also had different effects on actin stress fibers.
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Affiliation(s)
- Michela Montecchi-Palmer
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Jaclyn Y Bermudez
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Hannah C Webber
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
| | - Gaurang C Patel
- 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
| | - Weiming Mao
- North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas, United States
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12
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Bermudez JY, Montecchi-Palmer M, Mao W, Clark AF. Cross-linked actin networks (CLANs) in glaucoma. Exp Eye Res 2017; 159:16-22. [PMID: 28238754 DOI: 10.1016/j.exer.2017.02.010] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/07/2016] [Accepted: 02/22/2017] [Indexed: 12/22/2022]
Abstract
One of the major causes of decreased vision, irreversible vision loss and blindness worldwide is glaucoma. Increased intraocular pressure (IOP) is a major risk factor associated with glaucoma and its molecular mechanisms are not fully understood. The trabecular meshwork (TM) is the primary site of injury in glaucoma, and its dysfunction results in elevated IOP. The glaucomatous TM has increased extracellular matrix deposition as well as cytoskeletal rearrangements referred to as cross-linked actin networks (CLANs) that consist of dome like structures consisting of hubs and spokes. CLANs are thought to play a role in increased aqueous humor outflow resistance and increased IOP by creating stiffer TM cells and tissue. CLANs are inducible by glucocorticoids (GCs) and TGFβ2 in confluent TM cells and TM tissues. The signaling pathways of these induction agents give insight into the possible mechanisms of CLAN formation, but to date, the mechanism of CLANs regulation by these pathways has yet to be determined. Understanding the role CLANs play in IOP elevation and their mechanisms of induction and regulation may lead to novel treatment options to help prevent or intervene in glaucomatous damage to the trabecular meshwork.
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Affiliation(s)
- Jaclyn Y Bermudez
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, United States.
| | - Michela Montecchi-Palmer
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, United States.
| | - Weiming Mao
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, United States.
| | - Abbot F Clark
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX 76107, United States.
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13
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Fini ME, Schwartz SG, Gao X, Jeong S, Patel N, Itakura T, Price MO, Price FW, Varma R, Stamer WD. Steroid-induced ocular hypertension/glaucoma: Focus on pharmacogenomics and implications for precision medicine. Prog Retin Eye Res 2017; 56:58-83. [PMID: 27666015 PMCID: PMC5237612 DOI: 10.1016/j.preteyeres.2016.09.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 09/17/2016] [Accepted: 09/19/2016] [Indexed: 02/06/2023]
Abstract
Elevation of intraocular pressure (IOP) due to therapeutic use of glucocorticoids is called steroid-induced ocular hypertension (SIOH); this can lead to steroid-induced glaucoma (SIG). Glucocorticoids initiate signaling cascades ultimately affecting expression of hundreds of genes; this provides the potential for a highly personalized pharmacological response. Studies attempting to define genetic risk factors were undertaken early in the history of glucocorticoid use, however scientific tools available at that time were limited and progress stalled. In contrast, significant advances were made over the ensuing years in defining disease pathophysiology. As the genomics age emerged, it appeared the time was right to renew investigation into genetics. Pharmacogenomics is an unbiased discovery approach, not requiring an underlying hypothesis, and provides a way to pinpoint clinically significant genes and pathways that could not have been discovered any other way. Results of the first genome-wide association study to identify polymorphisms associated with SIOH, and follow-up on two novel genes linked to the disorder, GPR158 and HCG22, is discussed in the second half of the article. However, knowledge of genetic variants determining response to steroids in the eye also has value in its own right as a predictive and diagnostic tool. This article concludes with a discussion of how the Precision Medicine Initiative®, announced by U.S. President Obama in his 2015 State of the Union address, is beginning to touch the practice of ophthalmology. It is argued that SIOH/SIG may provide one of the next opportunities for effective application of precision medicine.
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Affiliation(s)
- M Elizabeth Fini
- USC Institute for Genetic Medicine and Department of Cell & Neurobiology, Keck School of Medicine of USC, University of Southern California, 2250 Alcatraz St., Suite 240, Los Angeles, CA, 90089, USA.
| | - Stephen G Schwartz
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, 3880 Tamiami Trail North, Naples, FL, 34103, USA.
| | - Xiaoyi Gao
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, 1905 W Taylor St., Suite 235, Chicago, IL, 60612, USA.
| | - Shinwu Jeong
- USC Institute for Genetic Medicine, USC Roski Eye Institute and Department of Ophthalmology, Keck School of Medicine of USC, University of Southern California, 2250 Alcatraz St., Suite 240, Los Angeles, CA, 90089, USA.
| | - Nitin Patel
- USC Institute for Genetic Medicine, Keck School of Medicine of USC, University of Southern California, 2250 Alcatraz St., Suite 240, Los Angeles, CA, 90089, USA.
| | - Tatsuo Itakura
- USC Institute for Genetic Medicine, Keck School of Medicine of USC, University of Southern California, 2250 Alcatraz St., Suite 240, Los Angeles, CA, 90089, USA.
| | - Marianne O Price
- Cornea Research Foundation of America, 9002 North Meridian Street, Indianapolis, IN, 46260, USA.
| | - Francis W Price
- Price Vision Group, 9002 North Meridian Street, Indianapolis, IN, 46260, USA.
| | - Rohit Varma
- Office of the Dean, USC Roski Eye Institute and Department of Ophthalmology, Keck School of Medicine of USC, University of Southern California, 1975 Zonal Ave., KAM 500, Los Angeles, CA, 90089, USA.
| | - W Daniel Stamer
- Department of Ophthalmology and Department of Biomedical Engineering, Duke University, AERI Room 4008, 2351 Erwin Rd, Durham, NC, 27705, USA.
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14
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Li G, Cui G, Dismuke WM, Navarro I, Perkumas K, Woodward DF, Stamer WD. Differential response and withdrawal profile of glucocorticoid-treated human trabecular meshwork cells. Exp Eye Res 2016; 155:38-46. [PMID: 27939447 DOI: 10.1016/j.exer.2016.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 09/21/2016] [Accepted: 12/03/2016] [Indexed: 12/15/2022]
Abstract
The goal of the study was to examine secreted protein response and withdrawal profiles from cultured human trabecular meshwork (HTM) cells following short- and long-term glucocorticoid treatment. Primary cultures of five human HTM cell strains isolated from 5 different individual donor eyes were tested. Confluent HTM cells were differentiated in culture media containing 1% FBS for at least one week, and then treated with Dexamethasone (Dex, 100 nM) 3 times/week for 1 or 4 weeks. Cell culture supernatants were collected 3 times per week for 8 weeks. Secretion profiles of myocilin (MYOC), matrix metalloproteinase-2 (MMP2) and fibronectin (FN) were determined by Western blot analysis and MMP2 activity by zymography. Dex treatment reduced MMP2 expression and activity, returning to normal levels shortly after Dex withdrawal in 5 HTM cell strains. All five cell strains significantly upregulated MYOC in response to Dex treatment by an average of 17-fold, but recovery to basal levels after Dex withdrawal took vastly different periods of time depending on cell strain and treatment duration. Dex treatment significantly increased FN secretion in all strains but one, which decreased FN secretion in the presence of Dex. Interestingly, secretion of FN and MYOC negatively correlated during a 4 week recovery period following 4 weeks of Dex treatment. Taken together, the time course and magnitude of response and recovery for three different secreted, extracellular matrix-associated proteins varied greatly between HTM cell strains, which may underlie susceptibility to glucocorticoid-induced ocular hypertension.
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Affiliation(s)
- Guorong Li
- Department of Ophthalmology, Duke University, Durham, NC, United States
| | - Gang Cui
- University of North Carolina at Chapel Hill, Collaborative Studies Coordinating Center, United States
| | - W Michael Dismuke
- Department of Ophthalmology, Duke University, Durham, NC, United States
| | - Iris Navarro
- Department of Ophthalmology, Duke University, Durham, NC, United States
| | - Kristin Perkumas
- Department of Ophthalmology, Duke University, Durham, NC, United States
| | | | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, NC, United States.
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15
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Paula JS, O'Brien C, Stamer WD. Life under pressure: The role of ocular cribriform cells in preventing glaucoma. Exp Eye Res 2016; 151:150-9. [PMID: 27567558 DOI: 10.1016/j.exer.2016.08.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2016] [Revised: 08/22/2016] [Accepted: 08/23/2016] [Indexed: 02/08/2023]
Abstract
Primary open-angle glaucoma is a multifactorial blinding disease often impacting the two pressure-sensitive regions of the eye: the conventional outflow pathway and the optic nerve head (ONH). The connective tissues that span these two openings in the globe are the trabecular meshwork of the conventional outflow pathway and the lamina cribrosa of the ONH. Resident cribiform cells of these two regions are responsible for actively remodeling and maintaining their connective tissues. In glaucoma, aberrant maintenance of the juxtacanalicular tissues (JCT) of the conventional outflow pathway results in ocular hypertension and pathological remodeling of the lamina cribrosa results in ONH cupping, damaging retinal ganglion cell axons. Interestingly, cells cultured from the lamina cribrosa and the JCT of the trabecular meshwork have similarities regarding gene expression, protein production, plus cellular responses to growth factors and mechanical stimuli. This review compares and contrasts the current knowledge of these two cell types, whose health is critical for protecting the eye from glaucomatous changes. In response to pressure gradients across their respective cribiform tissues, the goal is to better understand and differentiate healthy from pathological behavior of these two cell types.
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Affiliation(s)
- Jayter S Paula
- Department of Ophthalmology, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil; Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - Colm O'Brien
- Ophthalmology, UCD School of Medicine, Mater Hospital, Dublin, Ireland
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA.
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16
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Torrejon KY, Papke EL, Halman JR, Stolwijk J, Dautriche CN, Bergkvist M, Danias J, Sharfstein ST, Xie Y. Bioengineered glaucomatous 3D human trabecular meshwork as an in vitro disease model. Biotechnol Bioeng 2015; 113:1357-68. [PMID: 26615056 DOI: 10.1002/bit.25899] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/12/2015] [Accepted: 11/24/2015] [Indexed: 01/17/2023]
Abstract
Intraocular pressure (IOP) is mostly regulated by aqueous humor outflow through the human trabecular meshwork (HTM) and represents the only modifiable risk factor of glaucoma. The lack of IOP-modulating therapeutics that targets HTM underscores the need of engineering HTM for understanding the outflow physiology and glaucoma pathology in vitro. Using a 3D HTM model that allows for regulation of outflow in response to a pharmacologic steroid, a fibrotic state has been induced resembling that of glaucomatous HTM. This disease model exhibits HTM marker expression, ECM overproduction, impaired HTM cell phagocytic activity and outflow resistance, which represent characteristics found in steroid-induced glaucoma. In particular, steroid-induced ECM alterations in the glaucomatous model can be modified by a ROCK inhibitor. Altogether, this work presents a novel in vitro disease model that allows for physiological and pathological studies pertaining to regulating outflow, leading to improved understanding of steroid-induced glaucoma and accelerated discovery of new therapeutic targets. Biotechnol. Bioeng. 2016;113: 1357-1368. © 2015 Wiley Periodicals, Inc.
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Affiliation(s)
- Karen Y Torrejon
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, 12203, New York
| | - Ellen L Papke
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, 12203, New York
| | - Justin R Halman
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, 12203, New York
| | - Judith Stolwijk
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, 12203, New York
| | - Cula N Dautriche
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, 12203, New York
| | - Magnus Bergkvist
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, 12203, New York
| | - John Danias
- Department of Ophthalmology, SUNY Downstate Medical Center, Brooklyn, New York
| | - Susan T Sharfstein
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, 12203, New York
| | - Yubing Xie
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, 12203, New York.
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17
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Stamer WD, Braakman ST, Zhou EH, Ethier CR, Fredberg JJ, Overby DR, Johnson M. Biomechanics of Schlemm's canal endothelium and intraocular pressure reduction. Prog Retin Eye Res 2015; 44:86-98. [PMID: 25223880 PMCID: PMC4268318 DOI: 10.1016/j.preteyeres.2014.08.002] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 08/25/2014] [Accepted: 08/26/2014] [Indexed: 12/29/2022]
Abstract
Ocular hypertension in glaucoma develops due to age-related cellular dysfunction in the conventional outflow tract, resulting in increased resistance to aqueous humor outflow. Two cell types, trabecular meshwork (TM) and Schlemm's canal (SC) endothelia, interact in the juxtacanalicular tissue (JCT) region of the conventional outflow tract to regulate outflow resistance. Unlike endothelial cells lining the systemic vasculature, endothelial cells lining the inner wall of SC support a transcellular pressure gradient in the basal to apical direction, thus acting to push the cells off their basal lamina. The resulting biomechanical strain in SC cells is quite large and is likely to be an important determinant of endothelial barrier function, outflow resistance and intraocular pressure. This review summarizes recent work demonstrating how biomechanical properties of SC cells impact glaucoma. SC cells are highly contractile, and such contraction greatly increases cell stiffness. Elevated cell stiffness in glaucoma may reduce the strain experienced by SC cells, decrease the propensity of SC cells to form pores, and thus impair the egress of aqueous humor from the eye. Furthermore, SC cells are sensitive to the stiffness of their local mechanical microenvironment, altering their own cell stiffness and modulating gene expression in response. Significantly, glaucomatous SC cells appear to be hyper-responsive to substrate stiffness. Thus, evidence suggests that targeting the material properties of SC cells will have therapeutic benefits for lowering intraocular pressure in glaucoma.
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Affiliation(s)
- W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, NC 27710, USA; Department of Biomedical Engineering, Duke University, Durham, NC, 27710, USA.
| | - Sietse T Braakman
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
| | - Enhua H Zhou
- Department of Ophthalmology, Novartis Institutes of BioMedical Research, Cambridge, MA 02139, USA
| | - C Ross Ethier
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Atlanta, GA 30332, USA; Department of Biomedical Engineering, Emory University, Atlanta, GA 30322, USA; Department of Ophthalmology, Emory University, Atlanta, GA 30322, USA
| | - Jeffrey J Fredberg
- Program in Molecular and Integrative Physiological Sciences, Harvard School of Public Health, Boston, MA 02115, USA; Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115, USA
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
| | - Mark Johnson
- Department of Biomedical Engineering, Northwestern University, Evanston, IL, US; Department of Mechanical Engineering, Northwestern University, Evanston, IL, USA; Department of Ophthalmology Engineering, Northwestern University, Chicago, IL, USA
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18
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Yun H, Lathrop KL, Yang E, Sun M, Kagemann L, Fu V, Stolz DB, Schuman JS, Du Y. A laser-induced mouse model with long-term intraocular pressure elevation. PLoS One 2014; 9:e107446. [PMID: 25216052 PMCID: PMC4162591 DOI: 10.1371/journal.pone.0107446] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Accepted: 08/10/2014] [Indexed: 12/13/2022] Open
Abstract
Purpose To develop and characterize a mouse model with intraocular pressure (IOP) elevation after laser photocoagulation on the trabecular meshwork (TM), which may serve as a model to investigate the potential of stem cell-based therapies for glaucoma. Methods IOP was measured in 281 adult C57BL/6 mice to determine normal IOP range. IOP elevation was induced unilaterally in 50 adult mice, by targeting the TM through the limbus with a 532-nm diode laser. IOP was measured up to 24 weeks post-treatment. The optic nerve damage was detected by electroretinography and assessed by semiautomatic counting of optic nerve axons. Effects of laser treatment on the TM were evaluated by histology, immunofluorescence staining, optical coherence tomography (OCT) and transmission electron microscopy (TEM). Results The average IOP of C57BL/6 mice was 14.5±2.6 mmHg (Mean ±SD). After laser treatment, IOP averaged above 20 mmHg throughout the follow-up period of 24 weeks. At 24 weeks, 57% of treated eyes had elevated IOP with the mean IOP of 22.5±2.5 mmHg (Mean ±SED). The difference of average axon count (59.0%) between laser treated and untreated eyes was statistically significant. Photopic negative response (PhNR) by electroretinography was significantly decreased. CD45+ inflammatory cells invaded the TM within 1 week. The expression of SPARC was increased in the TM from 1 to 12 weeks. Histology showed the anterior chamber angle open after laser treatment. OCT indicated that most of the eyes with laser treatment had no synechia in the anterior chamber angles. TEM demonstrated disorganized and compacted extracellular matrix in the TM. Conclusions An experimental murine ocular hypertension model with an open angle and optic nerve axon loss was produced with laser photocoagulation, which could be used to investigate stem cell-based therapies for restoration of the outflow pathway integrity for ocular hypertension or glaucoma.
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Affiliation(s)
- Hongmin Yun
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Kira L. Lathrop
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Enzhi Yang
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Ming Sun
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Larry Kagemann
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Valeria Fu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Donna B. Stolz
- Department of Cell Biology, Center for Biologic Imaging, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Joel S. Schuman
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Yiqin Du
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
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19
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Functional and morphological characteristics of the retinal and choroidal vasculature. Prog Retin Eye Res 2014; 40:53-93. [DOI: 10.1016/j.preteyeres.2014.02.001] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 02/14/2014] [Accepted: 02/17/2014] [Indexed: 11/24/2022]
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20
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Inoue T, Tanihara H. Rho-associated kinase inhibitors: A novel glaucoma therapy. Prog Retin Eye Res 2013; 37:1-12. [DOI: 10.1016/j.preteyeres.2013.05.002] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Revised: 05/12/2013] [Accepted: 05/29/2013] [Indexed: 01/15/2023]
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21
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Adenovirus conducted connective tissue growth factor on extracellular matrix in trabecular meshwork and its role on aqueous humor outflow facility. Mol Biol Rep 2013; 40:6091-6. [PMID: 24052232 DOI: 10.1007/s11033-013-2720-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 09/14/2013] [Indexed: 10/26/2022]
Abstract
Deposition of extracellular matrix (ECM) in trabecular meshwork, such as fibronectin, collagen IV, elastin. leads to increased resistance of trabecular meshwork in primary open angle glaucoma (POAG). Connective tissue growth factor (CTGF) is known to regulate the ECM deposits. In this study, we detect the effect of adenovirus conducted CTGF (Adv-CTGF) transfection on either the expression of ECM components or aqueous humor outflow facility. Adv-CTGF was used to transfect rat trabecular meshwork cells in vivo and in vitro. Aqueous humor outflow facility was test by microbeads perfusion. Protein expression of CTGF, fibronectin, and collagen IV was determined using Western blot. In the Adv-CTGF group, the outflow facility displayed a significant decrease from baseline. It appears as though the transfection with Adv-CTGF significantly affects the aqueous humor outflow pattern. A negative correlation between IOP and PEFL indicated that a decrease in the area of bead deposition corresponded to an overall decrease of outflow, leading to an elevated IOP. Adv-CTGF can enhance the expression of CTGF, fibronectin and collagen IV. CTGF is the novel target for treatment of POAG. It is necessary to further study to test inhibition of CTGF expression for treatment of POAG.
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22
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Prendes MA, Harris A, Wirostko BM, Gerber AL, Siesky B. The role of transforming growth factor β in glaucoma and the therapeutic implications. Br J Ophthalmol 2013; 97:680-6. [PMID: 23322881 DOI: 10.1136/bjophthalmol-2011-301132] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Glaucoma is a progressive optic neuropathy frequently associated with elevated intraocular pressure, ocular vascular changes and extracellular matrix remodelling at the optic nerve head and in the trabecular meshwork. The pathogenesis is multifactorial and complex, but many recent studies have suggested that transforming growth factor-β (TGF-β) plays a major role in the process. Significantly elevated levels of TGF-β have been identified in the anterior chamber of glaucomatous eyes. TGF-β has also been shown to directly cause increased intraocular pressure. It is believed that this occurs through complex interaction with the trabecular meshwork, leading to decreased aqueous humour outflow. These processes occur through specific interactions with various proteins and signalling molecules also present in ocular tissues. By understanding the role that TGF-β plays in the pathogenesis of glaucoma, alternative therapeutic agents can be developed, which target these pathways and improve and assist in the management of disease. This review will cover previous investigative studies and discuss the current understanding of TGF-β's role in glaucoma and how it may serve as a potential therapeutic target.
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Affiliation(s)
- Mark A Prendes
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Tian B, Kaufman PL. Comparisons of actin filament disruptors and Rho kinase inhibitors as potential antiglaucoma medications. EXPERT REVIEW OF OPHTHALMOLOGY 2012; 7:177-187. [PMID: 22737177 PMCID: PMC3378243 DOI: 10.1586/eop.12.12] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Dynamics of the actin cytoskeleton in the trabecular meshwork play a crucial role in the regulation of trabecular outflow resistance. The actin filament disruptors and Rho kinase inhibitors affect the dynamics of the actomyosin system by either disrupting the actin filaments or inhibiting the Rho kinase-activated cellular contractility. Both approaches induce similar morphological changes and resistance decreases in the trabecular outflow pathway, and thus both have potential as antiglaucoma medications. Although the drugs might induce detrimental changes in the cornea following topical administration, lower drug concentrations in larger volumes as used clinically, but not higher drug concentrations in smaller volumes as used experimentally, could minimize corneal toxicity. Additionally, developments of trabecular meshwork-specific actin filament disruptors or Rho kinase inhibitors, prodrugs and new drug-delivery methods might avoid the drugs' toxicity to the cornea. Gene therapies with cytoskeleton-modulating proteins may mimic the effects of the cytoskeleton-modulating agents and have the potential to permanently decrease trabecular outflow resistance.
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Affiliation(s)
- Baohe Tian
- Department of Ophthalmology & Visual Sciences, University of Wisconsin-Madison, 600 Highland Avenue, Madison, WI 53792, USA
| | - Paul L Kaufman
- Department of Ophthalmology & Visual Sciences, University of Wisconsin-Madison, 600 Highland Avenue, Madison, WI 53792, USA
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Bollinger KE, Crabb JS, Yuan X, Putliwala T, Clark AF, Crabb JW. Quantitative proteomics: TGFβ₂ signaling in trabecular meshwork cells. Invest Ophthalmol Vis Sci 2011; 52:8287-94. [PMID: 21917933 DOI: 10.1167/iovs.11-8218] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
PURPOSE Transforming growth factor beta 2 (TGFβ₂) is often elevated in the aqueous humor (AH) and trabecular meshwork (TM) of patients with primary open-angle glaucoma (POAG) and appears to contribute to POAG pathogenesis. To better understand TGFβ₂ signaling in the eye, TGFβ₂-induced proteomic changes were identified in cells cultured from the TM, a tissue involved in intraocular pressure (IOP) elevation in glaucoma. METHODS Primary cultures of human TM cells from four donors were treated with or without TGFβ₂ (5 ng/mL) for 48 hours; then cellular protein was analyzed by liquid chromatography-mass spectrometry iTRAQ (isobaric tags for relative and absolute quantitation) technology. RESULTS A total of 853 proteins were quantified. TGFβ₂ treatment significantly altered the abundance of 47 proteins, 40 of which have not previously been associated with TGFβ₂ signaling in the eye. More than half the 30 elevated proteins support growing evidence that TGFβ₂ induces extracellular matrix remodeling and abnormal cytoskeletal interactions in the TM. The levels of 17 proteins were reduced, including four cytoskeletal and six regulatory proteins. Both elevated and decreased regulatory proteins implicate TGFβ₂-altered processes involving transcription, translation, and the glutamate/glutamine cycle. Altered levels of eight mitochondrial proteins support TGFβ₂-induced mitochondrial dysfunction in the TM that in POAG could contribute to oxidative damage in the AH outflow pathway, TM senescence, and elevated IOP. CONCLUSIONS The results expand the repertoire of proteins known to participate in TGFβ₂ signaling, provide new molecular insight into POAG, and establish a quantitative proteomics database for the TM that includes candidate glaucoma biomarkers for future validation studies.
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Izzotti A, Longobardi M, Cartiglia C, Rathschuler F, Saccà SC. Trabecular meshwork gene expression after selective laser trabeculoplasty. PLoS One 2011; 6:e20110. [PMID: 21747927 PMCID: PMC3128580 DOI: 10.1371/journal.pone.0020110] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Accepted: 04/12/2011] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Trabecular meshwork and Schlemm's canal are the tissues appointed to modulate the aqueous humour outflow from the anterior chamber. The impairment of their functions drives to an intraocular pressure increase. The selective laser trabeculoplasty is a laser therapy of the trabecular meshwork able to decrease intraocular pressure. The exact response mechanism to this treatment has not been clearly delineated yet. The herein presented study is aimed at studying the gene expression changes induced in trabecular meshwork cells by selective laser trabeculoplasty (SLT) in order to better understand the mechanisms subtending its efficacy. METHODOLOGY/PRINCIPAL FINDINGS Primary human trabecular meshwork cells cultured in fibroblast medium underwent selective laser trabeculoplasty treatment. RNA was extracted from a pool of cells 30 minutes after treatment while the remaining cells were further cultured and RNA was extracted respectively 2 and 6 hours after treatment. Control cells stored in incubator in absence of SLT treatment were used as reference samples. Gene expression was evaluated by hybridization on miRNA-microarray and laser scanner analysis. Scanning electron microscopic examination was performed on 2 Trabecular meshwork samples after SLT at 4(th) and 6(th) hour from treatment. On the whole, selective laser trabeculoplasty modulates in trabecular meshwork the expression of genes involved in cell motility, intercellular connections, extracellular matrix production, protein repair, DNA repair, membrane repair, reactive oxygen species production, glutamate toxicity, antioxidant activities, and inflammation. CONCLUSIONS/SIGNIFICANCE SLT did not induce any phenotypic alteration in TM samples. TM is a complex tissue possessing a great variety of function pivotal for the active regulation of aqueous humour outflow from the anterior chamber. SLT is able to modulate these functions at the postgenomic molecular level without inducing damage either at molecular or phenotypic levels.
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Affiliation(s)
- Alberto Izzotti
- Department of Health Sciences, Faculty of Medicine, University of Genoa, Genoa, Italy
| | | | - Cristina Cartiglia
- Department of Health Sciences, Faculty of Medicine, University of Genoa, Genoa, Italy
| | - Federico Rathschuler
- Ophthalmology Unit, Department of Head/Neck Pathologies, St. Martino Hospital, Genoa, Italy
| | - Sergio Claudio Saccà
- Ophthalmology Unit, Department of Head/Neck Pathologies, St. Martino Hospital, Genoa, Italy
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Lei Y, Overby DR, Read AT, Stamer WD, Ethier CR. A new method for selection of angular aqueous plexus cells from porcine eyes: a model for Schlemm's canal endothelium. Invest Ophthalmol Vis Sci 2010; 51:5744-50. [PMID: 20554623 DOI: 10.1167/iovs.10-5703] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The authors sought to develop a technique for isolating and culturing angular aqueous plexus (AAP) cells from more plentiful porcine eyes. AAP is an analogue of Schlemm's canal. METHODS Cells were differentially selected with puromycin, a toxin often used to select brain microvascular endothelial cells based on the expression of P-glycoprotein (P-gp), a multidrug resistance efflux pump. Trabecular meshwork containing AAP was dissected and pooled from fresh porcine eyes, digested in collagenase I, washed, filtered, and cultured for 8 days in a gelatin-coated plastic flask. Cells were then selected by exposure to 4 μg/mL puromycin for 2 days in the culture medium. Cells were fixed and immunostained for P-gp, ICAM II, von Willebrand factor (vWF), VE-cadherin, and α-smooth muscle actin (α-SMA). RESULTS Histology of the limbus showed that the dissection was limited to the trabecular meshwork region, including the AAP. Before puromycin treatment, cells appeared heterogeneous and polygonal, suggestive of a mixed population. More than 90% of the cells were removed by puromycin, leaving a population that appeared uniformly cobblestone-like when grown to confluence and that was contact inhibited. Puromycin-selected cells stained positively for the endothelial markers ICAM II, vWF, and VE-cadherin but negatively for α-SMA, consistent with staining patterns in whole tissue. CONCLUSIONS Based on marker expression, morphology, and behavior in culture, puromycin-selected cells from porcine outflow tissues are AAP endothelial cells. Thus, porcine eyes can provide a plentiful alternative cell source for studying Schlemm's canal biology related to ocular hypertension.
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Affiliation(s)
- Yuan Lei
- Department of Bioengineering, Imperial College London, London, United Kingdom
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van der Merwe EL, Kidson SH. Advances in imaging the blood and aqueous vessels of the ocular limbus. Exp Eye Res 2010; 91:118-26. [PMID: 20447395 DOI: 10.1016/j.exer.2010.04.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Revised: 04/16/2010] [Accepted: 04/26/2010] [Indexed: 10/19/2022]
Abstract
The vessels of the limbus play a pivotal role in the drainage of the major portion of aqueous humour from the anterior chamber. Aberrations in the limbal architecture can lead to raised intraocular pressure, which in turn can lead to blinding conditions such as glaucoma. Imaging these vessels in the normal eye, in development, and in conditions where there is anterior segment dysgenesis remains a challenge. Here we review the progress in limbal vessel imaging in the past 50 years and provide key information on their strengths and limitations. Included is an analysis of serial histological sectioning, ultrathin sections, microvascular perfusion with plastics and corrosion casting, X-ray microcomputed tomography, in vivo imaging including analysis of transgenic mice expressing GFP-vascular endothelium fusion proteins, in vivo microscopy imaging using fluorescent-labelled antibodies, slit-lamp microscopy and gonioscopy, fluorescein angiography, optical coherence tomography, and various labelling procedures for the vascular endothelium and the various forms of microscopy used to view these.
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Affiliation(s)
- E L van der Merwe
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, 7925 Cape Town, South Africa.
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Zeng D, Juzkiw T, Read AT, Chan DWH, Glucksberg MR, Ethier CR, Johnson M. Young's modulus of elasticity of Schlemm's canal endothelial cells. Biomech Model Mechanobiol 2010; 9:19-33. [PMID: 19387710 PMCID: PMC4319365 DOI: 10.1007/s10237-009-0156-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 04/02/2009] [Indexed: 01/29/2023]
Abstract
Schlemm's canal (SC) endothelial cells are likely important in the physiology and pathophysiology of the aqueous drainage system of the eye, particularly in glaucoma. The mechanical stiffness of these cells determines, in part, the extent to which they can support a pressure gradient and thus can be used to place limits on the flow resistance that this layer can generate in the eye. However, little is known about the biomechanical properties of SC endothelial cells. Our goal in this study was to estimate the effective Young's modulus of elasticity of normal SC cells. To do so, we combined magnetic pulling cytometry of isolated cultured human SC cells with finite element modeling of the mechanical response of the cell to traction forces applied by adherent beads. Preliminary work showed that the immersion angles of beads attached to the SC cells had a major influence on bead response; therefore, we also measured bead immersion angle by confocal microscopy, using an empirical technique to correct for axial distortion of the confocal images. Our results showed that the upper bound for the effective Young's modulus of elasticity of the cultured SC cells examined in this study, in central, non-nuclear regions, ranged between 1,007 and 3,053 Pa, which is similar to, although somewhat larger than values that have been measured for other endothelial cell types. We compared these values to estimates of the modulus of primate SC cells in vivo, based on images of these cells under pressure loading, and found good agreement at low intraocular pressure (8-15 mm Hg). However, increasing intraocular pressure (22-30 mm Hg) appeared to cause a significant increase in the modulus of these cells. These moduli can be used to estimate the extent to which SC cells deform in response to the pressure drop across the inner wall endothelium and thereby estimate the extent to which they can generate outflow resistance.
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Affiliation(s)
- Dehong Zeng
- Department of Biomedical Engineering, Northwestern University, Evanston, USA
| | - Taras Juzkiw
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Canada
| | - A. Thomas Read
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Canada
| | - Darren W.-H. Chan
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Canada
| | | | - C. Ross Ethier
- Department of Mechanical and Industrial Engineering, University of Toronto, Toronto, Canada. Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada. Department of Bioengineering, Imperial College London, London, UK
| | - Mark Johnson
- Department of Biomedical Engineering, Northwestern University, Evanston, USA
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Chapter 13 Outflow Signaling Mechanisms and New Therapeutic Strategies for the Control of Intraocular Pressure. CURRENT TOPICS IN MEMBRANES 2008. [DOI: 10.1016/s1063-5823(08)00413-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Toris CB, Camras CB. Chapter 8 Aqueous Humor Dynamics II. CURRENT TOPICS IN MEMBRANES 2008. [DOI: 10.1016/s1063-5823(08)00408-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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