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Verdoodt D, Peeleman N, Szewczyk K, Van Camp G, Ponsaerts P, Van Rompaey V. Cochlin Deficiency Protects Aged Mice from Noise-Induced Hearing Loss. Int J Mol Sci 2021; 22:ijms222111549. [PMID: 34768980 PMCID: PMC8584124 DOI: 10.3390/ijms222111549] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/19/2021] [Accepted: 10/23/2021] [Indexed: 12/18/2022] Open
Abstract
Several studies have shown that type IV fibrocytes, located in the spiral ligament, degenerate first after noise exposure. Interestingly, this is the region where Coch expression is most abundant. As it is suggested that cochlin plays a role in our innate immune system, our goal is to investigate hearing thresholds and inner ear inflammation after noise exposure in Coch knockout (Coch−/−) mice compared to Coch wildtype (Coch+/+) mice. Animals were randomly allocated to a noise exposure group and a control group. Vestibular and auditory testing was performed at 48 h and one week after noise exposure. Whole mount staining and cryosectioning of the cochlea was performed in order to investigate hair cells, spiral ganglion neurons, inner ear inflammation, Coch expression and fibrocyte degeneration. Hearing assessment revealed that Coch+/+ mice had significantly larger threshold shifts than Coch−/− mice after noise exposure. We were unable to identify any differences in hair cells, neurons, fibrocytes and influx of macrophages in the inner ear between both groups. Interestingly, Coch expression was significantly lower in the group exposed to noise. Our results indicate that the absence of Coch has a protective influence on hearing thresholds after noise exposure, but this is not related to reduced inner ear inflammation in the knockout.
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Affiliation(s)
- Dorien Verdoodt
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (N.P.); (K.S.); (V.V.R.)
- Laboratory of Experimental Hematology, Faculty of Medicine and Health Sciences, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, 2610 Wilrijk, Belgium;
- Correspondence: ; Tel.: +32-477-89-98-92
| | - Noa Peeleman
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (N.P.); (K.S.); (V.V.R.)
| | - Krystyna Szewczyk
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (N.P.); (K.S.); (V.V.R.)
| | - Guy Van Camp
- Centre of Medical Genetics, Faculty of Medicine and Health Sciences, University of Antwerp, 2650 Edegem, Belgium;
| | - Peter Ponsaerts
- Laboratory of Experimental Hematology, Faculty of Medicine and Health Sciences, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, 2610 Wilrijk, Belgium;
| | - Vincent Van Rompaey
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, 2610 Wilrijk, Belgium; (N.P.); (K.S.); (V.V.R.)
- Department of Otorhinolaryngology and Head & Neck Surgery, Antwerp University Hospital, 2650 Edegem, Belgium
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Kravchik MV, Novikov IA, Subbot AM, Antonov AA, Petrov SY, Pakhomova NA. [Accumulation of sulfur and phosphorus in the eye's drainage system in primary open-angle glaucoma]. Vestn Oftalmol 2020; 136:5-14. [PMID: 33084273 DOI: 10.17116/oftalma20201360615] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
PURPOSE To analyze the chemical composition of the sclera and trabecular meshwork in patients with primary open-angle glaucoma (POAG) and to assess the impact of corneal-compensated intraocular pressure (IOP) on the chemistry of the drainage area. MATERIAL AND METHODS Biopsy specimens of the trabecular meshwork (89 specimens) and sclera (41 specimens) obtained from patients with POAG on maximal medical therapy were analyzed to determine the content of certain chemical elements - carbon (C), nitrogen (N), oxygen (O), aluminum (Al), calcium (Ca), chlorine (Cl), potassium (K), magnesium (Mg), sodium (Na), phosphorus (P), silicon (Si) and sulfur (S). The elements were selected based on chemical structure target tissue and sensitivity of the method used for analysis. Visualization was performed using the «EVO LS 10» (Zeiss, Germany) scanning electron microscope (SEM), and the chemical composition was studied with the «Oxford-X-MAX-50» (Oxford, UK) energy-dispersive spectrometer (EDS). Statistical analysis was performed using the Spearman correlation. RESULTS The IOP of patients with POAG was found to have positive correlation with the total amount of S, P, and Ca in the trabecular meshwork. The accumulation of sulfur-containing compounds associated with pigment granules in trabecular meshwork's tissue was identified. A correlation was determined between the organic and inorganic (mineral) phosphorus content in the trabeculae, and the IOP values. The organic component of phosphorus was better represented than the mineral component in patients with increased IOP. CONCLUSION In patients with POAG, an increase in the IOP level causes the amount of S associated with pigment granules and the proportion of organic P to increase in the trabecular meshwork, which should be taken into account in the further search for drug therapy that would potentially affect pathologically altered tissue.
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Affiliation(s)
- M V Kravchik
- Research Institute of Eye Diseases, Moscow, Russia
| | - I A Novikov
- Research Institute of Eye Diseases, Moscow, Russia
| | - A M Subbot
- Research Institute of Eye Diseases, Moscow, Russia
| | - A A Antonov
- Research Institute of Eye Diseases, Moscow, Russia
| | - S Yu Petrov
- Research Institute of Eye Diseases, Moscow, Russia
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Cleaved Cochlin Sequesters Pseudomonas aeruginosa and Activates Innate Immunity in the Inner Ear. Cell Host Microbe 2019; 25:513-525.e6. [DOI: 10.1016/j.chom.2019.02.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 12/14/2018] [Accepted: 02/05/2019] [Indexed: 02/06/2023]
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Carreon T, van der Merwe E, Fellman RL, Johnstone M, Bhattacharya SK. Aqueous outflow - A continuum from trabecular meshwork to episcleral veins. Prog Retin Eye Res 2017; 57:108-133. [PMID: 28028002 PMCID: PMC5350024 DOI: 10.1016/j.preteyeres.2016.12.004] [Citation(s) in RCA: 185] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 11/14/2016] [Accepted: 12/22/2016] [Indexed: 12/22/2022]
Abstract
In glaucoma, lowered intraocular pressure (IOP) confers neuroprotection. Elevated IOP characterizes glaucoma and arises from impaired aqueous humor (AH) outflow. Increased resistance in the trabecular meshwork (TM), a filter-like structure essential to regulate AH outflow, may result in the impaired outflow. Flow through the 360° circumference of TM structures may be non-uniform, divided into high and low flow regions, termed as segmental. After flowing through the TM, AH enters Schlemm's canal (SC), which expresses both blood and lymphatic markers; AH then passes into collector channel entrances (CCE) along the SC external well. From the CCE, AH enters a deep scleral plexus (DSP) of vessels that typically run parallel to SC. From the DSP, intrascleral collector vessels run radially to the scleral surface to connect with AH containing vessels called aqueous veins to discharge AH to blood-containing episcleral veins. However, the molecular mechanisms that maintain homeostatic properties of endothelial cells along the pathways are not well understood. How these molecular events change during aging and in glaucoma pathology remain unresolved. In this review, we propose mechanistic possibilities to explain the continuum of AH outflow control, which originates at the TM and extends through collector channels to the episcleral veins.
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Affiliation(s)
- Teresia Carreon
- Department of Ophthalmology & Bascom Palmer Eye Institute, University of Miami, Miami, USA; Department of Biochemistry and Molecular Biology, University of Miami, Miami, USA
| | - Elizabeth van der Merwe
- Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Anzio Road, Observatory, 7925 Cape Town, South Africa
| | | | - Murray Johnstone
- Department of Ophthalmology, University of Washington, Seattle, WA, USA
| | - Sanjoy K Bhattacharya
- Department of Ophthalmology & Bascom Palmer Eye Institute, University of Miami, Miami, USA; Department of Biochemistry and Molecular Biology, University of Miami, Miami, USA.
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Giblin JP, Comes N, Strauss O, Gasull X. Ion Channels in the Eye: Involvement in Ocular Pathologies. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2015; 104:157-231. [PMID: 27038375 DOI: 10.1016/bs.apcsb.2015.11.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The eye is the sensory organ of vision. There, the retina transforms photons into electrical signals that are sent to higher brain areas to produce visual sensations. In the light path to the retina, different types of cells and tissues are involved in maintaining the transparency of avascular structures like the cornea or lens, while others, like the retinal pigment epithelium, have a critical role in the maintenance of photoreceptor function by regenerating the visual pigment. Here, we have reviewed the roles of different ion channels expressed in ocular tissues (cornea, conjunctiva and neurons innervating the ocular surface, lens, retina, retinal pigment epithelium, and the inflow and outflow systems of the aqueous humor) that are involved in ocular disease pathophysiologies and those whose deletion or pharmacological modulation leads to specific diseases of the eye. These include pathologies such as retinitis pigmentosa, macular degeneration, achromatopsia, glaucoma, cataracts, dry eye, or keratoconjunctivitis among others. Several disease-associated ion channels are potential targets for pharmacological intervention or other therapeutic approaches, thus highlighting the importance of these channels in ocular physiology and pathophysiology.
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Affiliation(s)
- Jonathan P Giblin
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Nuria Comes
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | | | - Xavier Gasull
- Universitat de Barcelona, Barcelona, Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.
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Bouhenni RA, Edward DP. Proteome of the anterior segment structure in relation to glaucoma. Proteomics Clin Appl 2014. [DOI: 10.1002/prca.201300051] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
| | - Deepak P. Edward
- King Khaled Eye Specialist Hospital; Riyadh Kingdom of Saudi Arabia
- Wilmer Eye Institute; John Hopkins University; Baltimore MD USA
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Abu-Hassan DW, Acott TS, Kelley MJ. The Trabecular Meshwork: A Basic Review of Form and Function. ACTA ACUST UNITED AC 2014; 2. [PMID: 25356439 DOI: 10.13188/2334-2838.1000017] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Affiliation(s)
- Diala W Abu-Hassan
- Casey Eye Institute, Department of Ophthalmology, Oregon Health & Science University, Portland, Oregon, USA
| | - Ted S Acott
- Department of Biochemistry & Molecular Biology, Oregon Health & Science University, Portland, Oregon, USA
| | - Mary J Kelley
- Department of Biochemistry & Physiology, University of Jordan, Amman, Jordan
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Hayakawa E, Landuyt B, Baggerman G, Cuyvers R, Lavigne R, Luyten W, Schoofs L. Peptidomic analysis of human reflex tear fluid. Peptides 2013; 42:63-9. [PMID: 23228955 DOI: 10.1016/j.peptides.2012.11.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2012] [Revised: 11/20/2012] [Accepted: 11/20/2012] [Indexed: 12/19/2022]
Abstract
Tear fluid is a complex mixture of biological compounds, including carbohydrates, lipids, electrolytes, proteins, and peptides. Despite the physiological importance of tear fluid, little is known about the identity of its endogenous peptides. In this study, we analyzed and identified naturally occurring peptide molecules in human reflex tear fluid by means of LC-MALDI-TOF-TOF. Tandem MS analyses revealed 30 peptides, most of which have not been identified before. Twenty-six peptides are derived from the proline-rich protein 4 and 4 peptides are derived from the polymeric immunoglobulin receptor. Based on their structural characteristics, we suggest that the identified tear fluid peptides contribute to the protective environment of the ocular surface.
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Affiliation(s)
- Eisuke Hayakawa
- Research Group of Functional Genomics and Proteomics, KU Leuven, B-3000 Leuven, Belgium.
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Analysis of COCHand TNFAVariants in East Indian Primary Open-Angle Glaucoma Patients. BIOMED RESEARCH INTERNATIONAL 2013; 2013:937870. [PMID: 24063017 PMCID: PMC3770021 DOI: 10.1155/2013/937870] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2013] [Revised: 07/18/2013] [Accepted: 07/23/2013] [Indexed: 11/17/2022]
Abstract
Glaucoma represents a heterogeneous group of optic neuropathies with a complex genetic basis. It is the second-largest cause of blindness in the world that reduces vision without warning and often without symptoms. Among 3 major subtypes of glaucoma, primary open-angle glaucoma (POAG) is the most common form. The focus of this study is to understand the molecular basis of the disease among Indian patients with respect to two genes, Cochlin (COCH) and tumor necrosis factor alpha (TNFA), selected based on reports of possible association with POAG. The genes were screened in patients and controls by PCR and direct sequencing. Although two novel changes (–450 C/T and –79 G/G) were identified in the 5′upstream region of COCH, no causal variant could be identified in either gene. –450 C/T was detected in 3 patients and 2 controls and –79 G/C in a single patient. Further, we did not observe significant association with the promoter SNPs of TNFA that had been previously reported to be associated with POAG pathogenesis. Thus, our study suggests lack of association of both COCH and TNFA with POAG pathogenesis.
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Jung E, Lee NK, Kang SK, Choi SH, Kim D, Park K, Choi K, Choi YJ, Jung DH. Identification of tissue-specific targeting peptide. J Comput Aided Mol Des 2012; 26:1267-75. [DOI: 10.1007/s10822-012-9614-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 10/19/2012] [Indexed: 12/17/2022]
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Edward DP, Bouhenni R. Anterior segment alterations and comparative aqueous humor proteomics in the buphthalmic rabbit (an American Ophthalmological Society thesis). TRANSACTIONS OF THE AMERICAN OPHTHALMOLOGICAL SOCIETY 2011; 109:66-114. [PMID: 22253484 PMCID: PMC3259673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
PURPOSE To use an integrated proteohistologic approach to gain insight into the anterior segment alterations in the buphthalmic rabbit. METHODS Eyes from 2- and 5-year-old buphthalmic and normal rabbits (n=20) were studied histologically. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) of aqueous humor (AH) was used to determine differential protein expression between animal groups. Western blot and immunohistochemistry were performed on selected differentially expressed proteins identified by LC-MS/MS. RESULTS The buphthalmic rabbits manifested a mild clinical phenotype with typical angle anomalies that appeared progressive by histology. Significantly thickened Descemet's membrane (DM) and anterior lens capsule in all buphthalmic rabbits showed increased fibronectin and collagen-IV immunolabeling. LC-MS/MS applying stringent filtering criteria revealed significant differential expression of several AH proteins in these rabbits. The protein of interest in the 2-year-old group was histidine-rich glycoprotein, and those in the 5-year-old group included alpha-2-HS-glycoprotein, clusterin, apolipoprotein E, interphotoreceptor retinoid-binding protein, transthyretin, cochlin, gelsolin, haptoglobin, hemopexin, and beta-2 microglobulin. The proteomic data for selected proteins was validated by Western blot and immunohistochemistry. A wide range of functional groups were affected by the altered AH proteins. These included extracellular matrix modulation, regulation of apoptosis, oxidative stress, and protein transport. CONCLUSIONS Multiple anterior segment alterations were histologically identified in the buphthalmic rabbits that showed progressive changes with age. The differentially expressed AH proteins in these rabbits suggest a multifunctional role for AH in modulating pathologic changes in DM, anterior lens capsule, and the angular meshwork in these animals.
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Affiliation(s)
- Deepak P Edward
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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Schraermeyer M, Schnichels S, Julien S, Heiduschka P, Bartz-Schmidt KU, Schraermeyer U. Ultrastructural analysis of the pigment dispersion syndrome in DBA/2J mice. Graefes Arch Clin Exp Ophthalmol 2009; 247:1493-504. [DOI: 10.1007/s00417-009-1146-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Accepted: 06/27/2009] [Indexed: 11/30/2022] Open
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Ju WK, Kim KY, Angert M, Duong-Polk KX, Lindsey JD, Ellisman MH, Weinreb RN. Memantine blocks mitochondrial OPA1 and cytochrome c release and subsequent apoptotic cell death in glaucomatous retina. Invest Ophthalmol Vis Sci 2009; 50:707-16. [PMID: 18936150 PMCID: PMC2678967 DOI: 10.1167/iovs.08-2499] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine whether intraocular pressure (IOP) elevation alters OPA1 expression and triggers OPA1 release, as well as whether the uncompetitive N-methyl-d-aspartate (NMDA) glutamate receptor antagonist memantine blocks OPA1 release and subsequent apoptotic cell death in glaucomatous DBA/2J mouse retina. METHODS Preglaucomatous DBA/2J mice received memantine (5 mg/kg, intraperitoneal injection, twice daily for 3 months) and IOP in the eyes was measured monthly. RGC loss was counted after FluoroGold labeling. OPA1, Dnm1, Bcl-2, and Bax mRNA were measured by qPCR. OPA1 protein was assessed by immunohistochemistry and Western blot. Apoptotic cell death was assessed by TUNEL staining. RESULTS Memantine treatment significantly increased RGC survival in glaucomatous DBA/2J mice and increased the 75-kDa OPA1 isoform, but did not alter the 80- and 90-kDa isoforms. The isoforms of OPA1 were significantly increased in the cytosol of the vehicle-treated glaucomatous retinas but were significantly decreased in memantine-treated glaucomatous retinas. OPA1 immunoreactivity was decreased in the photoreceptors of both vehicle- and memantine-treated glaucomatous retinas, but was increased in the outer plexiform layer of only the memantine-treated glaucomatous retinas. Memantine blocked apoptotic cell death in the GCL, increased Bcl-2 gene expression, and decreased Bax gene expression. CONCLUSIONS OPA1 release from mitochondria in glaucomatous mouse retina is inhibited by blockade of glutamate receptor activation. Because this OPA1 effect was accompanied by increased Bcl-2 expression, decreased Bax expression, and apoptosis blockade, glutamate receptor activation in the glaucomatous retina may involve a distinct mitochondria-mediated cell death pathway.
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Affiliation(s)
- Won-Kyu Ju
- Hamilton Glaucoma Center, University of California San Diego, La Jolla, California 92037, USA.
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Bhattacharya SK, Gabelt BT, Ruiz J, Picciani R, Kaufman PL. Cochlin expression in anterior segment organ culture models after TGFbeta2 treatment. Invest Ophthalmol Vis Sci 2008; 50:551-9. [PMID: 18836166 DOI: 10.1167/iovs.08-2632] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
PURPOSE To determine the effect of transforming growth factor (TGF)-beta2 treatment on intraocular pressure (IOP), outflow facility, and cochlin expression in vitro in monkey and pig organ-cultured anterior segments (MOCAS and POCAS). METHODS MOCAS (rhesus and cynomolgus) or POCAS were infused with media containing 10 ng/mL TGFbeta2 to one segment of each pair and 0.1% BSA (vehicle) to the contralateral segment for up to 14 days at a constant rate. Cochlin expression was determined by immunohistochemical study, ELISA, and Western blot analysis using chicken polyclonal antibodies against different regions of cochlin. RESULTS TGFbeta2 infusion produced elevated IOP in MOCAS (usually after 5 days), that was approximately 45% greater than baseline and compared to control segments. Outflow facility (OF) was decreased by approximately 40% compared with pretreatment baseline (n=5). In POCAS (n=7), IOP was increased (approximately 3 days) by approximately 75% compared with baseline and contralateral changes. The IOP elevation subsided thereafter. Cochlin levels increased with duration of TGFbeta2 treatment in the media and in the region of the trabecular meshwork in both species. CONCLUSIONS TGFbeta2-induced IOP elevation was associated with an increase in cochlin secretion into the media and expression in the tissue of MOCAS and POCAS. Whether cochlin overexpression contributes to elevated IOP or is a consequence of other changes relevant to IOP elevation remains to be determined.
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Ju WK, Kim KY, Lindsey JD, Angert M, Duong-Polk KX, Scott RT, Kim JJ, Kukhmazov I, Ellisman MH, Perkins GA, Weinreb RN. Intraocular pressure elevation induces mitochondrial fission and triggers OPA1 release in glaucomatous optic nerve. Invest Ophthalmol Vis Sci 2008; 49:4903-11. [PMID: 18469184 DOI: 10.1167/iovs.07-1661] [Citation(s) in RCA: 112] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine whether elevation of intraocular pressure (IOP) triggers mitochondrial fission and ultrastructural changes and alters optic atrophy type 1 (OPA1) expression and distribution in the optic nerve (ON) of glaucomatous DBA/2J mice. METHODS IOP in the eyes of DBA/2J mice was measured, and mitochondrial structural changes were assessed by conventional electron microscopy (EM) and EM tomography. Cytochrome c oxidase IV subunit 1 (COX), OPA1, and Dnm1, a rat homologue of dynamin-related protein-1, mRNA were measured by quantitative (q)PCR. COX and OPA1 protein distribution was assessed by immunocytochemistry and Western blot. RESULTS Excavation of the optic nerve head (ONH), axon loss, and COX reduction were evident in 10-month-old glaucomatous ONHs of eyes with >20 mm Hg IOP elevation. EM analysis showed mitochondrial fission, matrix swelling, substantially reduced cristae volume, and abnormal cristae depletion in 10-month-old glaucomatous ONH axons. The mean length of mitochondrial cross section in these axons decreased from 858.2 +/- 515.3 nm in 3-month-old mice to 583.3 +/- 298.6 nm in 10-month-old glaucomatous mice (P < 0.001). Moderate reductions of COX mRNA were observed in the 10-month-old DBA/2J mice's ONHs. Larger reductions of OPA1 immunoreactivity and gene expression were coupled with larger increases of Dnm1 gene expression in 10-month-old glaucomatous ONH. Subcellular fractionation analysis indicates increased release of both OPA1 and cytochrome c from mitochondria in 10-month-old glaucomatous ONs. CONCLUSIONS IOP elevation may directly damage mitochondria in the ONH axons by promoting reduction of COX, mitochondrial fission and cristae depletion, alterations of OPA1 and Dnm1 expression, and induction of OPA1 release. Thus, interventions to preserve mitochondria may be useful for protecting against ON degeneration in glaucoma.
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Affiliation(s)
- Won-Kyu Ju
- Department of Ophthalmology, Hamilton Glaucoma Center, School of Medicine, University of California San Diego, La Jolla, California 92037-0946, USA
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Wang WH, McNatt LG, Pang IH, Millar JC, Hellberg PE, Hellberg MH, Steely HT, Rubin JS, Fingert JH, Sheffield VC, Stone EM, Clark AF. Increased expression of the WNT antagonist sFRP-1 in glaucoma elevates intraocular pressure. J Clin Invest 2008; 118:1056-64. [PMID: 18274669 DOI: 10.1172/jci33871] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 12/19/2007] [Indexed: 12/19/2022] Open
Abstract
Elevated intraocular pressure (IOP) is the principal risk factor for glaucoma and results from excessive impedance of the fluid outflow from the eye. This abnormality likely originates from outflow pathway tissues such as the trabecular meshwork (TM), but the associated molecular etiology is poorly understood. We discovered what we believe to be a novel role for secreted frizzled-related protein-1 (sFRP-1), an antagonist of Wnt signaling, in regulating IOP. sFRP1 was overexpressed in human glaucomatous TM cells. Genes involved in the Wnt signaling pathway were expressed in cultured TM cells and human TM tissues. Addition of recombinant sFRP-1 to ex vivo perfusion-cultured human eyes decreased outflow facility, concomitant with reduced levels of beta-catenin, the Wnt signaling mediator, in the TM. Intravitreal injection of an adenoviral vector encoding sFRP1 in mice produced a titer-dependent increase in IOP. Five days after vector injection, IOP increased 2 fold, which was significantly reduced by topical ocular administration of an inhibitor of a downstream suppressor of Wnt signaling. Thus, these data indicate that increased expression of sFRP1 in the TM appears to be responsible for elevated IOP in glaucoma and restoring Wnt signaling in the TM may be a novel disease intervention strategy for treating glaucoma.
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Picciani R, Desai K, Guduric-Fuchs J, Cogliati T, Morton CC, Bhattacharya SK. Cochlin in the eye: functional implications. Prog Retin Eye Res 2007; 26:453-69. [PMID: 17662637 PMCID: PMC2064858 DOI: 10.1016/j.preteyeres.2007.06.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Aqueous humor is actively produced in the ciliary epithelium of the anterior chamber and has important functions for the eye. Under normal physiological conditions, the inflow and outflow of the aqueous humor are tightly regulated, but in the pathologic state this balance is lost. Aqueous outflow involves structures of the anterior chamber and experiences most resistance at the level of the trabecular meshwork (TM) that acts as a filter. The modulation of the TM structure regulates the filter and its mechanism remains poorly understood. Proteomic analyses have identified cochlin, a protein of poorly understood function, in the glaucomatous TM but not in healthy control TM from human cadaver eyes. The presence of cochlin has subsequently been confirmed by Western and immunohistochemical analyses. Functionally, cochlin undergoes multimerization induced by shear stress and other changes in the microenvironment. Cochlin along with mucopolysaccharide deposits has been found in the TM of glaucoma patients and in the inner ear of subjects affected by the hearing disorder DNFA9, a late-onset, progressive disease that also involves alterations in fluid shear regimes. In vitro, cochlin induces aggregation of primary TM cells suggesting a role in cell adhesion, possibly in mechanosensation, and in modulation of the TM filter.
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Affiliation(s)
- Renata Picciani
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, 33136
| | - Kavita Desai
- Bascom Palmer Eye Institute, University of Miami, Miami, Florida, 33136
| | - Jasenka Guduric-Fuchs
- Centre for Vision Sciences, Queen's University School of Biomedical Sciences, BELFAST BT12 6BA, UK
| | - Tiziana Cogliati
- Centre for Vision Sciences, Queen's University School of Biomedical Sciences, BELFAST BT12 6BA, UK
| | - Cynthia C. Morton
- Harvard Medical School, Brigham and Women's Hospital New Research Building, Room 160D, 77 Avenue Louis Pasteur, Boston, MA 02115
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