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Ren R, Humphrey AA, Kopczynski C, Gong H. Rho Kinase Inhibitor AR-12286 Reverses Steroid-Induced Changes in Intraocular Pressure, Effective Filtration Areas, and Morphology in Mouse Eyes. Invest Ophthalmol Vis Sci 2023; 64:7. [PMID: 36734964 PMCID: PMC9907372 DOI: 10.1167/iovs.64.2.7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2022] [Accepted: 01/11/2023] [Indexed: 02/04/2023] Open
Abstract
Purpose We investigated mechanisms of reduction of intraocular pressure (IOP) by Rho kinase inhibitor AR-12286 in steroid-induced ocular hypertension (SIOH). Methods C57BL/6 mice (N = 56) were randomly divided into Saline, dexamethasone (DEX), DEX + AR-12286, and DEX-discontinuation (DEX-DC) groups. IOP was measured weekly during the first four weeks in all groups. Beginning at week 5, the DEX-DC group was followed without treatment until IOP returned to normal, and the other groups were treated as assigned with IOP measured every other day for another week. Fluorescent tracer was injected into the anterior chamber to visualize the outflow pattern in the trabecular meshwork (TM) and TM effective filtration area (EFA) was determined. Radial sections from both high- and low-tracer regions were processed for electron microscopy. Results AR-12286 reduced IOP in SIOH mouse eyes in one day (P < 0.01). At the end of week 5, mean IOP in the DEX + AR-12286 group was ∼4 mm Hg lower than DEX group (P < 0.001) and ∼2 mm Hg lower than DEX-DC group (P < 0.05). After one-week AR-12286 treatment (P < 0.05) or five-week DC of DEX (P < 0.01), DEX-induced reduction of EFA was rescued and DEX-induced morphological changes in the TM were partially reversed. Conclusions AR-12286 reversed steroid-induced morphological changes in the TM and reduced EFA, which correlated with reduced IOP in SIOH eyes. AR-12286 reduced IOP elevation in SIOH eyes more effectively than discontinuing DEX treatment even when accompanied by continuous DEX treatment. Therefore Rho kinase inhibitors may lower SIOH in patients who rely on steroid treatment.
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Affiliation(s)
- Ruiyi Ren
- Boston University School of Medicine, Department of Ophthalmology, Boston, Massachusetts, United States
| | - Anne A. Humphrey
- Boston University School of Medicine, Department of Ophthalmology, Boston, Massachusetts, United States
| | - Casey Kopczynski
- Aerie Pharmaceuticals, Inc., Durham, North Carolina, United States
| | - Haiyan Gong
- Boston University School of Medicine, Department of Ophthalmology, Boston, Massachusetts, United States
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Faralli JA, Filla MS, Peters DM. Integrin Crosstalk and Its Effect on the Biological Functions of the Trabecular Meshwork/Schlemm’s Canal. Front Cell Dev Biol 2022; 10:886702. [PMID: 35573686 PMCID: PMC9099149 DOI: 10.3389/fcell.2022.886702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/05/2022] [Indexed: 11/20/2022] Open
Abstract
Integrins are a family of heterodimeric receptors composed of an α- and β-subunit that mediate cell-adhesion to a number of extracellular matrix (ECM) proteins in the Trabecular Meshwork/Schlemm’s canal (TM/SC) of the eye. Upon binding an ECM ligand, integrins transmit signals that activate a number of signaling pathways responsible for regulating actin-mediated processes (i.e phagocytosis, cell contractility, and fibronectin fibrillogenesis) that play an important role in regulating intraocular pressure (IOP) and may be involved in glaucoma. An important function of integrin-mediated signaling events is that the activity of one integrin can affect the activity of other integrins in the same cell. This creates a crosstalk that allows TM/SC cells to respond to changes in the ECM presumably induced by the mechanical forces on the TM/SC, aging and disease. In this review, we discuss how integrin crosstalk influences the function of the human TM/SC pathway. In particular, we will discuss how different crosstalk pathways mediated by either the αvβ3 or α4β1 integrins can play opposing roles in the TM when active and therefore act as on/off switches to modulate the cytoskeleton-mediated processes that regulate the outflow of aqueous humor through the TM/SC.
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Affiliation(s)
- Jennifer A. Faralli
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Mark S. Filla
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Donna M. Peters
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
- *Correspondence: Donna M. Peters,
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Yang YF, Sun YY, Peters DM, Keller KE. The Effects of Mechanical Stretch on Integrins and Filopodial-Associated Proteins in Normal and Glaucomatous Trabecular Meshwork Cells. Front Cell Dev Biol 2022; 10:886706. [PMID: 35573666 PMCID: PMC9100841 DOI: 10.3389/fcell.2022.886706] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/11/2022] [Indexed: 01/29/2023] Open
Abstract
The trabecular meshwork (TM) is the tissue responsible for regulating aqueous humor fluid egress from the anterior eye. If drainage is impaired, intraocular pressure (IOP) becomes elevated, which is a primary risk factor for primary open angle glaucoma. TM cells sense elevated IOP via changes in their biomechanical environment. Filopodia cellular protrusions and integrin transmembrane proteins may play roles in detecting IOP elevation, yet this has not been studied in detail in the TM. Here, we investigate integrins and filopodial proteins, such as myosin-X (Myo10), in response to mechanical stretch, an in vitro technique that produces mechanical alterations mimicking elevated IOP. Pull-down assays showed Myo10 binding to α5 but not the β1 subunit, αvβ3, and αvβ5 integrins. Several of these integrins colocalized in nascent adhesions in the filopodial tip and shaft. Using conformation-specific antibodies, we found that β1 integrin, but not α5 or αvβ3 integrins, were activated following 1-h mechanical stretch. Cadherin -11 (CDH11), a cell adhesion molecule, did not bind to Myo10, but was associated with filopodia. Interestingly, CDH11 was downregulated on the TM cell surface following 1-h mechanical stretch. In glaucoma cells, CDH11 protein levels were increased. Finally, mechanical stretch caused a small, yet significant increase in Myo10 protein levels in glaucoma cells, but did not affect cellular communication of fluorescent vesicles via filopodia-like tunneling nanotubes. Together, these data suggest that TM cell adhesion proteins, β1 integrin and CDH11, have relatively rapid responses to mechanical stretch, which suggests a central role in sensing changes in IOP elevation in situ.
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Affiliation(s)
- Yong-Feng Yang
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States
| | - Ying Ying Sun
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States
| | - Donna M. Peters
- Department of Pathology and Laboratory Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, United States
| | - Kate E. Keller
- Casey Eye Institute, Oregon Health & Science University, Portland, OR, United States,Department of Chemical Physiology and Biochemistry, Oregon Health & Science University, Portland, OR, United States,*Correspondence: Kate E. Keller,
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Wang Y, Wang W, Yang X, Chen W, Yang X, Pan X, Xu P, Zhu W, Han Y, Chen X. ITGA8 positive cells in the conventional outflow tissue exhibit Schlemm's canal endothelial cell properties. Life Sci 2021; 278:119564. [PMID: 33961857 DOI: 10.1016/j.lfs.2021.119564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/19/2021] [Accepted: 04/23/2021] [Indexed: 11/17/2022]
Abstract
AIMS Elevated intraocular pressure is primarily induced by the increased resistance of conventional outflow of aqueous humor. Dysfunction of the juxtacanalicular region of trabecular meshwork (TM) and Schlemm's canal (SC) endothelium, as the main conventional outflow tissue, have been implicated as the major reasons for the increased resistance. Integrins are widespread in these tissues, especially alpha8 integrin (ITGA8). We aim to investigate the properties of cells expressing ITGA8 in the conventional outflow tissue. MAIN METHODS Fluorescence in situ hybridization (FISH) and immunofluorescence (IF) were performed to detect the mRNA and protein levels of ITGA8 in human conventional outflow tissue. ITGA8-positive cells were isolated from the cultured human TM cells through a magnetic bead-based approach. Flow Cytometry was used to determine the purification efficiency. The expressions of TM and SC biomarkers and dexamethasone-induced myocilin secretion capacity of ITGA8-positive cells was assessed by Real-time PCR, IF and Western blot. A gel contraction assay was performed to evaluate contractility of ITGA8-positive cells after endothelin 1 treatment. KEY FINDINGS ITGA8 was found with robust expression near the inner wall of SC endothelium. After purification, the proportion of ITGA8-positive cells were increased by about 10%. ITGA8-positive cells were identified with the properties as SC endothelial cells, such as more robust expressions of SC biomarkers, less dexamethasone-inducible myocilin expression, and stronger contractility. SIGNIFICANCE This study demonstrated that cells expressing ITGA8 in SC region possess more properties as SC endothelial cells. Our data implicate a crucial role of ITGA8 in aqueous humor (AH) outflow resistance regulation.
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Affiliation(s)
- Yanan Wang
- School of Basic Medicine, Qingdao University, Qingdao 266021, China; Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao 266021, China
| | - Wenyan Wang
- School of Basic Medicine, Qingdao University, Qingdao 266021, China; Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao 266021, China
| | - Xuejiao Yang
- Affiliated Hospital of Qingdao University, Qingdao 266003, China
| | - Wenshi Chen
- Affiliated Hospital of Qingdao University, Qingdao 266003, China
| | - Xian Yang
- Affiliated Hospital of Qingdao University, Qingdao 266003, China
| | - Xiaojing Pan
- Qingdao Eye Hospital, Shandong Eye Institute, Shandong Academy of Medical Sciences, Qingdao 266071, China
| | - Peilong Xu
- State Key Laboratory of Bio-Fibers and Eco-Textiles, Qingdao University, Qingdao 266071, China
| | - Wei Zhu
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao 266021, China; Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang, University & Capital Medical University, Beijing 100730, China
| | - Yantao Han
- School of Basic Medicine, Qingdao University, Qingdao 266021, China.
| | - Xuehong Chen
- School of Basic Medicine, Qingdao University, Qingdao 266021, China.
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Faralli JA, Filla MS, Peters DM. Role of Fibronectin in Primary Open Angle Glaucoma. Cells 2019; 8:E1518. [PMID: 31779192 PMCID: PMC6953041 DOI: 10.3390/cells8121518] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 11/22/2019] [Accepted: 11/24/2019] [Indexed: 01/08/2023] Open
Abstract
Primary open angle glaucoma (POAG) is the most common form of glaucoma and the 2nd most common cause of irreversible vision loss in the United States. Nearly 67 million people have the disease worldwide including >3 million in the United States. A major risk factor for POAG is an elevation in intraocular pressure (IOP). The increase in IOP is believed to be caused by an increase in the deposition of extracellular matrix proteins, in particular fibronectin, in a region of the eye known as the trabecular meshwork (TM). How fibronectin contributes to the increase in IOP is not well understood. The increased density of fibronectin fibrils is thought to increase IOP by altering the compliance of the trabecular meshwork. Recent studies, however, also suggest that the composition and organization of fibronectin fibrils would affect IOP by changing the cell-matrix signaling events that control the functional properties of the cells in the trabecular meshwork. In this article, we will discuss how changes in the properties of fibronectin and fibronectin fibrils could contribute to the regulation of IOP.
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Affiliation(s)
- Jennifer A. Faralli
- Departments of Pathology & Laboratory Medicine, University of Wisconsin, Madison, WI 53706, USA; (J.A.F.); (M.S.F.)
| | - Mark S. Filla
- Departments of Pathology & Laboratory Medicine, University of Wisconsin, Madison, WI 53706, USA; (J.A.F.); (M.S.F.)
| | - Donna M. Peters
- Departments of Pathology & Laboratory Medicine, University of Wisconsin, Madison, WI 53706, USA; (J.A.F.); (M.S.F.)
- Ophthalmology & Visual Sciences, University of Wisconsin, Madison, WI 53706, USA
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Faralli JA, Filla MS, Peters DM. Effect of αvβ3 Integrin Expression and Activity on Intraocular Pressure. Invest Ophthalmol Vis Sci 2019; 60:1776-1788. [PMID: 31022732 PMCID: PMC6485315 DOI: 10.1167/iovs.18-26038] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Purpose To determine the effects of αvβ3 integrin expression and activation on intraocular pressure (IOP). Methods Cre+/−β3flox/flox mice were treated with topical tamoxifen eye drops for 5 days to activate Cre and excise the β3 integrin gene from the anterior segment. IOP was measured weekly for 11 weeks using rebound tonometry. Mice were then killed and changes in expression of the β3 integrin subunit in Cre+/− β3flox/flox mice were determined using Western blotting analysis and immunofluorescence microscopy. To determine the effect of αvβ3 integrin activation on outflow facility, porcine organ culture anterior segments (POCAS) were perfused with the αvβ3 integrin-activating antibody AP5 or an isotype IgG control for 21 hours. The effect of αvβ3 integrin activation on IOP was measured over 7 days in C57BL/6J mice intracamerally infused with AP5, AP3, IgG, or PBS. Results Deletion of the β3 integrin subunit using the tamoxifen-inducible Cre-loxP system resulted in a decrease in expression of the β3 integrin subunit in the trabecular meshwork and ciliary muscle. Morphologically no gross changes in the anterior segment were detected. Deletion of the β3 integrin subunit resulted in a significantly (P < 0.05) lower IOP in mice within 2 weeks following the tamoxifen treatment and persisted for 11 weeks. Activating the αvβ3 integrin with the AP5 antibody resulted in a significant (P < 0.05) increase in IOP in C57BL/6J mice and a decrease in outflow facility in 42% of the POCAS. Conclusions These studies demonstrate a role for αvβ3 integrin signaling in the regulation of IOP.
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Affiliation(s)
- Jennifer A Faralli
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States
| | - Mark S Filla
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States
| | - Donna M Peters
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States.,Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States
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7
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Ren R, Li G, Le TD, Kopczynski C, Stamer WD, Gong H. Netarsudil Increases Outflow Facility in Human Eyes Through Multiple Mechanisms. Invest Ophthalmol Vis Sci 2017; 57:6197-6209. [PMID: 27842161 PMCID: PMC5114035 DOI: 10.1167/iovs.16-20189] [Citation(s) in RCA: 95] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Purpose Netarsudil is a Rho kinase/norepinephrine transporter inhibitor currently in phase 3 clinical development for glaucoma treatment. We investigated the effects of its active metabolite, netarsudil-M1, on outflow facility (C), outflow hydrodynamics, and morphology of the conventional outflow pathway in enucleated human eyes. Methods Paired human eyes (n = 5) were perfused with either 0.3 μM netarsudil-M1 or vehicle solution at constant pressure (15 mm Hg). After 3 hours, fluorescent microspheres were added to perfusion media to trace the outflow patterns before perfusion-fixation. The percentage effective filtration length (PEFL) was calculated from the measured lengths of tracer distribution in the trabecular meshwork (TM), episcleral veins (ESVs), and along the inner wall (IW) of Schlemm's canal after global and confocal imaging. Morphologic changes along the trabecular outflow pathway were investigated by confocal, light, and electron microscopy. Results Perfusion with netarsudil-M1 significantly increased C when compared to baseline (51%, P < 0.01) and to paired controls (102%, P < 0.01), as well as significantly increased PEFL in both IW (P < 0.05) and ESVs (P < 0.01). In treated eyes, PEFL was significantly higher in ESVs than in the IW (P < 0.01) and was associated with increased cross-sectional area of ESVs (P < 0.01). Percentage effective filtration length in ESVs positively correlated with the percentage change in C (R2 = 0.58, P = 0.01). A significant increase in juxtacanalicular connective tissue (JCT) thickness (P < 0.05) was found in treated eyes compared to controls. Conclusions Netarsudil acutely increased C by expansion of the JCT and dilating the ESVs, which led to redistribution of aqueous outflow through a larger area of the IW and ESVs.
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Affiliation(s)
- Ruiyi Ren
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States 2Department of Anatomoy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Guorong Li
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Thuy Duong Le
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States
| | - Casey Kopczynski
- Aerie Pharmaceuticals, Inc., Durham, North Carolina, United States
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Haiyan Gong
- Department of Ophthalmology, Boston University School of Medicine, Boston, Massachusetts, United States 2Department of Anatomoy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, United States
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8
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The role of integrins in glaucoma. Exp Eye Res 2016; 158:124-136. [PMID: 27185161 DOI: 10.1016/j.exer.2016.05.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 05/06/2016] [Accepted: 05/10/2016] [Indexed: 01/04/2023]
Abstract
Integrins are a family of heterodimeric transmembrane receptors that mediate adhesion to the extracellular matrix (ECM). In addition to their role as adhesion receptors, integrins can act as ''bidirectional signal transducers'' that coordinate a large number of cellular activities in response to the extracellular environment and intracellular signaling events. This bidirectional signaling helps maintain tissue homeostasis. Dysregulated bidirectional signaling, however, could trigger the propagation of feedback loops that can lead to the establishment of a disease state such as glaucoma. Here we discuss the role of integrins and bidirectional signaling as they relate to the glaucomatous phenotype with special emphasis on the αvβ3 integrin. We present evidence that this particular integrin may have a significant impact on the pathogenesis of glaucoma.
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9
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Gonzalez JM, Ko MK, Pouw A, Tan JCH. Tissue-based multiphoton analysis of actomyosin and structural responses in human trabecular meshwork. Sci Rep 2016; 6:21315. [PMID: 26883567 PMCID: PMC4756353 DOI: 10.1038/srep21315] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Accepted: 01/21/2016] [Indexed: 01/15/2023] Open
Abstract
The contractile trabecular meshwork (TM) modulates aqueous humor outflow resistance and intraocular pressure. The primary goal was to visualize and quantify human TM contractile state by analyzing actin polymerization (F-actin) by 2-photon excitation fluorescence imaging (TPEF) in situ. A secondary goal was to ascertain if structural extracellular matrix (ECM) configuration changed with contractility. Viable ex vivo human TM was incubated with latrunculin-A (Lat-A) or vehicle prior to Alexa-568-phalloidin labeling and TPEF. Quantitative image analysis was applied to 2-dimensional (2D) optical sections and 3D image reconstructions. After Lat-A exposure, (a) the F-actin network reorganized as aggregates; (b) F-actin-associated fluorescence intensity was reduced by 48.6% (mean; p = 0.007; n = 8); (c) F-actin 3D distribution was reduced by 68.9% (p = 0.040); (d) ECM pore cross-sectional area and volume were larger by 36% (p = 0.032) and 65% (p = 0.059) respectively and pores appeared more interconnected; (e) expression of type I collagen and elastin, key TM structural ECM proteins, were unaltered (p = 0.54); and (f) tissue viability was unchanged (p = 0.39) relative to vehicle controls. Thus Lat-A-induced reduction of actomyosin contractility was associated with TM porous expansion without evidence of reduced structural ECM protein expression or cellular viability. These important subcellular-level dynamics could be visualized and quantified within human tissue by TPEF.
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Affiliation(s)
- Jose M Gonzalez
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Minhee K Ko
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Andrew Pouw
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - James C H Tan
- Doheny Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA
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Roy Chowdhury U, Hann CR, Stamer WD, Fautsch MP. Aqueous humor outflow: dynamics and disease. Invest Ophthalmol Vis Sci 2015; 56:2993-3003. [PMID: 26024085 DOI: 10.1167/iovs.15-16744] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Affiliation(s)
- Uttio Roy Chowdhury
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - Cheryl R Hann
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University, Durham, North Carolina, United States
| | - Michael P Fautsch
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, United States
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11
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Slauson SR, Peters DM, Schwinn MK, Kaufman PL, Gabelt BT, Brandt CR. Viral Vector Effects on Exoenzyme C3 Transferase-Mediated Actin Disruption and on Outflow Facility. Invest Ophthalmol Vis Sci 2015; 56:2431-8. [PMID: 25783606 DOI: 10.1167/iovs.14-15909] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Purified Clostridium botulinum exoenzyme C3 transferase (C3) effects on the actin cytoskeleton in human trabecular meshwork cells (HTM) and on the outflow facility response in monkey organ-cultured anterior segments (MOCAS) were determined in the presence or absence of viral vectors. METHODS Human adenovirus type 5 (AdV) and feline immunodeficiency virus (FIV) vectors were produced using kits. Cell soluble purified C3 (C3cs) was purchased commercially. Recombinant C3 (C3rec) cDNA was overexpressed in Escherichia coli and purified. The HTM cells were incubated with up to 10 μg/mL C3cs or with 5 μg of C3rec and/or viral vector (multiplicity of infection [MOI] = 25). Cells then were fixed and stained for actin. Outflow facility in MOCAS was measured at baseline, 4 hours, 24 hours, and 3 to 4 days following bolus injection of AdV (1.6 × 107 transducing units) and/or 2.5 μg C3rec. RESULTS The HTM cells treated for 4 hours with C3cs (all doses) or for 24 hours with C3rec developed a rounded morphology and lost stress fibers. Cells transduced with vectors alone showed no changes at any time point. Cells exposed to C3rec and cotransduced with either viral vector showed significant disruption of the actin cytoskeleton within 4 hours after exposure, which persisted at 24 hours. In MOCAS, the AdV vector alone had no effect on outflow facility, but enhanced the response to C3rec at 4 hours. CONCLUSIONS Coadministration of viral vectors enhances the ability of C3 transferase to disrupt actin stress fiber formation in HTM cells and increase outflow facility in MOCAS. Viral vectors potentially could be used to increase the bioavailability of proteins for cells that are difficult to transfect.
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Affiliation(s)
- Sarah R Slauson
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States
| | - Donna M Peters
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States 2Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States 3McPherson Eye Research Institute, Uni
| | - Marie K Schwinn
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, United States
| | - Paul L Kaufman
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States 3McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States
| | - B'Ann T Gabelt
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States
| | - Curtis R Brandt
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States 3McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States
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Hann CR, Fautsch MP. Recent Developments in Understanding the Role of Aqueous Humor Outflow in Normal and Primary Open Angle Glaucoma. CURRENT OPHTHALMOLOGY REPORTS 2015; 3:67-73. [PMID: 26236568 DOI: 10.1007/s40135-015-0072-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Primary open angle glaucoma (POAG) is the second leading cause of blindness in the world's rapidly aging population. POAG is characterized by progressive degeneration of neural structures in the posterior segment, often associated with a concomitant elevation of intraocular pressure. Changes in IOP are believed to be caused by a disruption in the normal outflow of aqueous humor. This article reviews recent research associated with normal and POAG aqueous humor outflow. Novel findings elucidating biochemical and pathological changes in the ocular tissues affected in POAG are presented. Stem cell research, identification of lymphatic markers, and increased use of mouse models give researchers exciting new tools to understand aqueous humor outflow, changes associated with POAG and identify underlying causes of the disease.
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Affiliation(s)
- Cheryl R Hann
- Department of Ophthalmology Mayo Clinic 200 First Street SW Rochester, MN 55905 USA
| | - Michael P Fautsch
- Department of Ophthalmology Mayo Clinic 200 First Street SW Rochester, MN 55905 USA
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Swaminathan SS, Oh DJ, Kang MH, Rhee DJ. Aqueous outflow: segmental and distal flow. J Cataract Refract Surg 2015; 40:1263-72. [PMID: 25088623 DOI: 10.1016/j.jcrs.2014.06.020] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Revised: 06/13/2014] [Accepted: 06/14/2014] [Indexed: 12/29/2022]
Abstract
UNLABELLED The elevated intraocular pressure (IOP) of primary open-angle glaucoma is caused by impaired outflow of aqueous humor through the trabecular meshwork. Within the juxtacanalicular region, alterations of both extracellular matrix homeostasis and the cellular tone of trabecular meshwork endothelial and the inner wall of Schlemm canal cells affect outflow. Newer pharmacologic agents that target trabecular meshwork and Schlemm canal cell cytoskeleton lower IOP. Aqueous drainage occurs nonhomogenously with greater flow going through certain portions of the TM and less going through other portions-a concept known as segmental flow, which is theoretically the result of outflow being dependent on the presence of discrete pores within Schlemm canal. The limited long-term success of trabecular meshwork bypass surgeries implicates the potential impact of resistance in Schlemm canal itself and collector channels. Additionally, others have observed that outflow occurs preferentially near collector channels. These distal structures may be more important to aqueous outflow than previously believed. FINANCIAL DISCLOSURE Dr. Rhee is a consultant to Aerie Pharmaceuticals, Alcon Laboratories, Inc., Allegan, Inc., Aquesys, Inc., Glaukos Corp., Ivantis, Inc., Johnson & Johnson, Merck Sharp & Dohme Corp. and Santen, Inc., and has received research funding from Alcon Laboratories, Inc., Merck Sharp & Dohme Corp., and Ivantis, Inc. No other author has a financial or proprietary interest in any material or method mentioned.
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Affiliation(s)
- Swarup S Swaminathan
- From Harvard-MIT Division of Health Sciences and Technology (Swaminathan), Harvard Medical School, Boston, Massachusetts, and the Department of Ophthalmology & Visual Sciences (Oh, Kang, Rhee), Case Western Reserve University, Cleveland, Ohio, USA
| | - Dong-Jin Oh
- From Harvard-MIT Division of Health Sciences and Technology (Swaminathan), Harvard Medical School, Boston, Massachusetts, and the Department of Ophthalmology & Visual Sciences (Oh, Kang, Rhee), Case Western Reserve University, Cleveland, Ohio, USA
| | - Min Hyung Kang
- From Harvard-MIT Division of Health Sciences and Technology (Swaminathan), Harvard Medical School, Boston, Massachusetts, and the Department of Ophthalmology & Visual Sciences (Oh, Kang, Rhee), Case Western Reserve University, Cleveland, Ohio, USA
| | - Douglas J Rhee
- From Harvard-MIT Division of Health Sciences and Technology (Swaminathan), Harvard Medical School, Boston, Massachusetts, and the Department of Ophthalmology & Visual Sciences (Oh, Kang, Rhee), Case Western Reserve University, Cleveland, Ohio, USA.
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14
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Dautriche CN, Xie Y, Sharfstein ST. Walking through trabecular meshwork biology: Toward engineering design of outflow physiology. Biotechnol Adv 2014; 32:971-83. [PMID: 24806891 DOI: 10.1016/j.biotechadv.2014.04.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 04/22/2014] [Accepted: 04/29/2014] [Indexed: 01/23/2023]
Abstract
According to the World Health Organization, glaucoma remains the second leading cause of blindness in the world. Glaucoma belongs to a group of optic neuropathies that is characterized by chronic degeneration of the optic nerve along with its supporting glia and vasculature. Despite significant advances in the field, there is no available cure for glaucoma. The trabecular meshwork has been implicated as the primary site for regulation of intraocular pressure, the only known modifiable factor in glaucoma development. In this review, we describe the current models for glaucoma studies, primary culture, anterior eye segments, and animal studies and their limitations. These models, especially anterior eye segments and animal tissues, often require careful interpretation given the inter-species variation and are cumbersome and expensive. The lack of an available in vitro 3D model to study trabecular meshwork cells and detailed mechanisms of their regulation of intraocular pressure has limited progress in the field of glaucoma research. In this paper, we review the current status of knowledge of the trabecular meshwork and how the current advances in tissue engineering techniques might be applied in an effort to engineer a synthetic trabecular meshwork as a 3D in vitro model to further advance glaucoma research. In addition, we describe strategies for selection and design of biomaterials for scaffold fabrication as well as extracellular matrix components to mimic and support the trabecular architecture. We also discuss possible uses for a bioengineered trabecular meshwork for both developing a fundamental understanding of trabecular meshwork biology as well as high-throughput screening of glaucoma drugs.
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Affiliation(s)
- Cula N Dautriche
- SUNY College of Nanoscale Science and Engineering, 257 Fuller Road, Albany, NY 12203, USA
| | - Yubing Xie
- SUNY College of Nanoscale Science and Engineering, 257 Fuller Road, Albany, NY 12203, USA
| | - Susan T Sharfstein
- SUNY College of Nanoscale Science and Engineering, 257 Fuller Road, Albany, NY 12203, USA.
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15
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Adhikari N, Billaud M, Carlson M, Lake SP, Montaniel KRC, Staggs R, Guan W, Walek D, Desir S, Isakson BE, Barocas VH, Hall JL. Vascular biomechanical properties in mice with smooth muscle specific deletion of Ndst1. Mol Cell Biochem 2014; 385:225-38. [PMID: 24101444 PMCID: PMC4853023 DOI: 10.1007/s11010-013-1831-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 09/26/2013] [Indexed: 12/19/2022]
Abstract
Heparan sulfate proteoglycans act as co-receptors for many chemokines and growth factors. The sulfation pattern of the heparan sulfate chains is a critical regulatory step affecting the binding of chemokines and growth factors. N-deacetylase-N-sulfotransferase1 (Ndst1) is one of the first enzymes to catalyze sulfation. Previously published work has shown that HSPGs alter tangent moduli and stiffness of tissues and cells. We hypothesized that loss of Ndst1 in smooth muscle would lead to significant changes in heparan sulfate modification and the elastic properties of arteries. In line with this hypothesis, the axial tangent modulus was significantly decreased in aorta from mice lacking Ndst1 in smooth muscle (SM22αcre(+)Ndst1(-/-), p < 0.05, n = 5). The decrease in axial tangent modulus was associated with a significant switch in myosin and actin types and isoforms expressed in aorta and isolated aortic vascular smooth muscle cells. In contrast, no changes were found in the compliance of smaller thoracodorsal arteries of SM22αcre(+)Ndst1(-/-) mice. In summary, the major findings of this study were that targeted ablation of Ndst1 in smooth muscle cells results in altered biomechanical properties of aorta and differential expression of myosin and actin types and isoforms.
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Affiliation(s)
- Neeta Adhikari
- Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Marie Billaud
- Robert M Berne Cardiovascular Research Center, School of Medicine, University of Virginia, Charlottesville, VA 22908
| | - Marjorie Carlson
- Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Spencer P. Lake
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, MN 55455
| | - Kim Ramil C. Montaniel
- Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Rod Staggs
- Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Weihua Guan
- Department of Biostatistics, University of Minnesota, Minneapolis, MN 55455
| | - Dinesha Walek
- Biomedical Genomics Center, University of Minnesota, Minneapolis, MN 55455
| | - Snider Desir
- Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
| | - Brant E. Isakson
- Robert M Berne Cardiovascular Research Center, School of Medicine, University of Virginia, Charlottesville, VA 22908
| | - Victor H. Barocas
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota, MN 55455
| | - Jennifer L. Hall
- Lillehei Heart Institute, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
- Division of Cardiology, Department of Medicine, University of Minnesota, Minneapolis, MN 55455
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16
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Gagen D, Faralli JA, Filla MS, Peters DM. The role of integrins in the trabecular meshwork. J Ocul Pharmacol Ther 2013; 30:110-20. [PMID: 24266581 DOI: 10.1089/jop.2013.0176] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Integrins are a family of heterodimeric transmembrane receptors that mediate adhesion to the extracellular matrix (ECM). However, integrins are not just adhesion receptors. They can act as "bidirectional signal transducers" that coordinate a large number of cellular activities in response to the extracellular environment and intracellular signaling events. Among the activities regulated by integrins are cell adhesion, assembly of the ECM, growth factor signaling, apoptosis, organization of the cytoskeleton, and cytoskeleton-mediated processes such as contraction, endocytosis, and phagocytosis. Integrins regulate these activities through a complex network of intracellular signaling kinases and adaptor proteins that associate with the transmembrane and cytoplasmic domains of the integrin subunits. In this review, we will discuss how some of the known integrin-mediated activities can control the function of the trabecular meshwork. We will also discuss how integrin activity is a tightly regulated process that involves conformation changes within the heterodimer which are mediated by specific integrin-binding proteins.
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Affiliation(s)
- Debjani Gagen
- 1 Department of Pathology and Laboratory Medicine, Medical Science Center, University of Wisconsin , Madison, Wisconsin
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17
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Medina-Ortiz WE, Belmares R, Neubauer S, Wordinger RJ, Clark AF. Cellular fibronectin expression in human trabecular meshwork and induction by transforming growth factor-β2. Invest Ophthalmol Vis Sci 2013; 54:6779-88. [PMID: 24030464 DOI: 10.1167/iovs.13-12298] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
PURPOSE Levels of TGF-β2 are higher in POAG aqueous humor, causing deposition of extracellular matrix (ECM) proteins, including fibronectin (FN), in the glaucomatous human trabecular meshwork (HTM) that may be responsible for elevated IOP. The purpose of this study was to identify the expression of cellular FN (cFN) isoforms (EDA and EDB) in HTM cells and tissues, and to determine whether TGF-β2 can induce cFN expression and fibril formation in cultured HTM cells. METHODS Expression of cFN mRNA isoforms and induction by recombinant TGF-β2 (5 ng/mL) were determined by quantitative RT-PCR. The TGF-β2 induction of EDA isoform protein expression and FN fibril formation were analyzed using Western immunoblots and immunocytochemistry (ICC), respectively. Immunohistochemistry (IHC) analysis was used to examine total FN and EDA isoform expression in normal (NTM) and glaucomatous (GTM) trabecular meshwork (TM) tissues. RESULTS Both cFN mRNA isoforms were expressed in cultured HTM cells and were induced by TGF-β2 after 2, 4, and 7 days (P < 0.05). Similarly, EDA isoform protein and fibril formation were increased after 4 and 7 days of TGF-β2 treatment. Finally, GTM tissues had significantly greater EDA isoform protein levels (1.7-fold, P < 0.05) compared to NTM tissues. CONCLUSIONS This study demonstrated that cFN isoforms are expressed and induced in HTM cells by TGF-β2. Also, increased EDA isoform protein levels were seen in GTM tissues. Our findings suggest that induction of cFN isoform expression in the TM ECM may be a novel pathologic mechanism involved in the TM changes associated with glaucoma.
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Affiliation(s)
- Wanda E Medina-Ortiz
- Department of Cell Biology and Anatomy, and the North Texas Eye Research Institute, University of North Texas Health Science Center, Fort Worth, Texas
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18
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Gagen D, Filla MS, Clark R, Liton P, Peters DM. Activated αvβ3 integrin regulates αvβ5 integrin-mediated phagocytosis in trabecular meshwork cells. Invest Ophthalmol Vis Sci 2013; 54:5000-11. [PMID: 23821196 DOI: 10.1167/iovs.13-12084] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
PURPOSE To investigate the roles of αvβ3 and αvβ5 integrins in phagocytosis in human trabecular meshwork (HTM) cells. METHODS Immunofluorescence microscopy and FACS analysis were used to determine levels of αvβ3 and αvβ5 integrins in TM tissue and cultures of normal and immortalized TM cells. Phagocytosis was measured using pHrodo-labeled S. aureus bioparticles followed by FACS analysis. The role of αvβ5 integrin in phagocytosis was evaluated by knocking down αvβ5 integrin expression with siRNA against the human β5 gene. Signaling from focal adhesion kinase (FAK) was blocked using FAK inhibitor 14. The role of αvβ3 integrins in phagocytosis was determined by treating HTM cells with dexamethasone (DEX) or ethanol (EtOH) and by generating stable cell lines that overexpressed either wild type (WT) or constitutively active (CA) β3 integrin subunit. RESULTS Both TM tissue and cell lines expressed αvβ3 and αvβ5 integrins. Knockdown of αvβ5 integrin reduced phagocytosis by ∼60% and FAK inhibition significantly reduced phagocytosis up to 84%, in a dose-dependent manner. DEX treatment increased αvβ3 integrin expression in HTM cells but reduced phagocytosis by ∼50% compared with untreated and EtOH-treated cells. The CA β3 integrin-expressing cell line showed increased αvβ3 integrin levels and decreased phagocytosis by ∼50% compared with the control. CONCLUSIONS The αvβ5 integrin-FAK-mediated pathway regulates phagocytosis in TM cells and this pathway is inhibited by activation of αvβ3 integrins. This suggests that changes in integrin expression and activity may be responsible for alterations in phagocytosis observed in steroid induced glaucoma.
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Affiliation(s)
- Debjani Gagen
- Department of Pathology & Laboratory Medicine, University of Wisconsin, Madison, Wisconsin 53706, USA
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19
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Abstract
PURPOSE OF REVIEW Regulation of intraocular pressure by the conventional (trabecular) outflow pathway is complicated, involving a myriad of mechanical and chemical signals. In most, intraocular pressure is maintained within a tight range over a lifetime. Unfortunately in some, dysfunction results in ocular hypertension and open-angle glaucoma. In the context of established knowledge, this review summarizes recent investigations of conventional outflow function, with the goal of identifying areas for future inquiry and therapeutic targeting. RECENT FINDINGS Mechanical stimulation of conventional outflow cells due to intraocular pressure fluctuations impacts contractility, gene expression, pore formation, enzyme activity, and signaling. Numerous local signaling mediators in the conventional pathway such as bioactive lipids, cytokines, nitric oxide, and nucleotides participate in the regulation of outflow. Interestingly outflow through the conventional pathway is not uniform, but segmental, with passageways constantly changing due to focal protease activity of trabecular cells clearing extracellular matrix materials. The relationship between extracellular matrix expression and trabecular meshwork contractility appears to coordinately impact outflow resistance and is the target of a new class of drugs, the Rho kinase inhibitors. SUMMARY The conventional outflow pathway is a dynamic, pressure-sensitive tissue that is vulnerable to pathology on many fronts, each representing a therapeutic opportunity.
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20
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Integrins in trabecular meshwork and optic nerve head: possible association with the pathogenesis of glaucoma. BIOMED RESEARCH INTERNATIONAL 2013; 2013:202905. [PMID: 23586020 PMCID: PMC3613054 DOI: 10.1155/2013/202905] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 02/07/2013] [Indexed: 02/02/2023]
Abstract
Integrins are a family of membrane-spanning proteins that are important receptors for cell adhesion to extracellular matrix proteins. They also provide connections between the extracellular environment and intracellular cytoskeletons and are responsible for activation of many intracellular signaling pathways. In vitro and in vivo data strongly indicate that integrin-mediated signaling events can modulate the organization of the actin cytoskeleton in trabecular meshwork (TM) cells and are associated with astrocyte migration and microglia activation of the optic nerve head in patients with primary open angle glaucoma. Consequently, increase in resistance in the TM outflow pathways and remodeling of the optic nerve head occur, which in turn increases intraocular pressure (IOP), adds additional mechanical stress and strain to optic nerve axons, and accelerates damage of axons initially caused by optic nerve head remodeling. Integrins appear to be ideal candidates for translating physical stress and strain into cellular responses known to occur in glaucomatous optic neuropathy.
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21
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Gonzalez JM, Heur M, Tan JCH. Two-photon immunofluorescence characterization of the trabecular meshwork in situ. Invest Ophthalmol Vis Sci 2012; 53:3395-404. [PMID: 22531697 DOI: 10.1167/iovs.11-8570] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To develop an in situ model to study biological responses and glaucoma pathology in the human trabecular meshwork (TM). Characteristic TM cell- and glaucoma-associated markers were localized in situ in relation to the tissue's autofluorescent structural extracellular matrix (ECM) by two-photon excitation fluorescence optical sectioning (TPEF). METHODS Human donor corneoscleral (CS) tissue containing the intact aqueous drainage tract was incubated with dexamethasone (Dex) or TGF-β1, and immunostained for epifluorescence (EF) microscopy with antibodies to myocilin and alpha smooth muscle (α-SMA). Separate specimens were labeled for Type-IV collagen and fibronectin. Nuclei were stained with Hoechst 33342. Multimodal TPEF was used to visualize EF, intravital dyes, and autofluorescence (AF) in situ. Three-dimensional (3D) localization of fluorescence within the TM was analyzed using reconstruction software. RESULTS Autofluorescent beams, perforated sheets, and fibers, consistent with the uveal (UV), CS, and juxtacanalicular (JCT) meshwork, respectively, were captured at different depths of the TM. Type-IV collagen EF distinctly outlined the AF beams in a location consistent with basement membrane. Fibronectin EF showed a diffuse reticular pattern throughout the TM. TGF-β1-induced α-SMA expression, which was distributed perinuclearly in cells among autofluorescent structures. Dex-induced myocilin expression had both cytosolic and extracellular distributions. CONCLUSIONS The authors have localized markers that are characteristic of TM cells and relevant to glaucoma pathogenesis in situ using multimodal TPEF without conventional histological embedding and sectioning. Protein expression was inducible in situ and could be analyzed with respect to cells and the ECM within the 3D environment of the human TM.
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Affiliation(s)
- Jose M Gonzalez
- Doheny Eye Institute and Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA
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22
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23
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Cook-Mills JM, Marchese ME, Abdala-Valencia H. Vascular cell adhesion molecule-1 expression and signaling during disease: regulation by reactive oxygen species and antioxidants. Antioxid Redox Signal 2011; 15:1607-38. [PMID: 21050132 PMCID: PMC3151426 DOI: 10.1089/ars.2010.3522] [Citation(s) in RCA: 370] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The endothelium is immunoregulatory in that inhibiting the function of vascular adhesion molecules blocks leukocyte recruitment and thus tissue inflammation. The function of endothelial cells during leukocyte recruitment is regulated by reactive oxygen species (ROS) and antioxidants. In inflammatory sites and lymph nodes, the endothelium is stimulated to express adhesion molecules that mediate leukocyte binding. Upon leukocyte binding, these adhesion molecules activate endothelial cell signal transduction that then alters endothelial cell shape for the opening of passageways through which leukocytes can migrate. If the stimulation of this opening is blocked, inflammation is blocked. In this review, we focus on the endothelial cell adhesion molecule, vascular cell adhesion molecule-1 (VCAM-1). Expression of VCAM-1 is induced on endothelial cells during inflammatory diseases by several mediators, including ROS. Then, VCAM-1 on the endothelium functions as both a scaffold for leukocyte migration and a trigger of endothelial signaling through NADPH oxidase-generated ROS. These ROS induce signals for the opening of intercellular passageways through which leukocytes migrate. In several inflammatory diseases, inflammation is blocked by inhibition of leukocyte binding to VCAM-1 or by inhibition of VCAM-1 signal transduction. VCAM-1 signal transduction and VCAM-1-dependent inflammation are blocked by antioxidants. Thus, VCAM-1 signaling is a target for intervention by pharmacological agents and by antioxidants during inflammatory diseases. This review discusses ROS and antioxidant functions during activation of VCAM-1 expression and VCAM-1 signaling in inflammatory diseases.
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Affiliation(s)
- Joan M Cook-Mills
- Allergy-Immunology Division, Northwestern University Feinberg School of Medicine, 240 E Huron, Chicago, IL 60611, USA.
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Faralli JA, Newman JR, Sheibani N, Dedhar S, Peters DM. Integrin-linked kinase regulates integrin signaling in human trabecular meshwork cells. Invest Ophthalmol Vis Sci 2011; 52:1684-92. [PMID: 21071740 DOI: 10.1167/iovs.10-6397] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine whether integrin-linked kinase (ILK) controls the organization of the actin cytoskeleton in the trabecular meshwork (TM) by regulating integrin co-signaling. METHODS The cell binding domain and the Heparin II (Hep II) domain of fibronectin were used to activate α5β1 and α4β1 integrin signaling, respectively, in differentiated human TM (HTM) cells. The role of ILK was determined using either ILK small interfering RNA (siRNA) to knockout ILK expression or the ILK inhibitors, KP392 and QLT0267. The knockdown of ILK expression was verified by Western blot analysis. The presence of actin stress fibers and focal adhesions was determined by labeling cultures with phalloidin and anti-talin or ILK antibodies, respectively. RESULTS Cell spreading in differentiated HTM cells required ILK, since ILK siRNA and the ILK inhibitors significantly reduced cell spreading, actin polymerization, and the localization of talin and ILK in focal adhesions (FAs). Both cell spreading and the localization of talin and ILK to FAs in differentiated HTM cells could be rescued by inducing α4β1 integrin signaling with a recombinant Hep II domain of fibronectin, even though α4β1 integrins were not found in FAs. In the absence of ILK inhibition, the Hep II domain had minimal effect on α5β1 integrin-mediated spreading. CONCLUSIONS This study suggests that cooperative α5β1/α4β1 integrin signaling may be regulated by ILK trans-dominantly and that alterations in ILK activity may affect actin cytoskeleton organization and contractility in the TM.
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Affiliation(s)
- Jennifer A Faralli
- Department of Pathology and Laboratory Medicine, University of Wisconsin, Madison, Wisconsin, USA
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