1
|
Wishart TFL, Lovicu FJ. Heparan sulfate proteoglycans (HSPGs) of the ocular lens. Prog Retin Eye Res 2023; 93:101118. [PMID: 36068128 DOI: 10.1016/j.preteyeres.2022.101118] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/22/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022]
Abstract
Heparan sulfate proteoglycans (HSPGs) reside in most cells; on their surface, in the pericellular milieu and/or extracellular matrix. In the eye, HSPGs can orchestrate the activity of key signalling molecules found in the ocular environment that promote its development and homeostasis. To date, our understanding of the specific roles played by individual HSPG family members, and the heterogeneity of their associated sulfated HS chains, is in its infancy. The crystalline lens is a relatively simple and well characterised ocular tissue that provides an ideal stage to showcase and model the expression and unique roles of individual HSPGs. Individual HSPG core proteins are differentially localised to eye tissues in a temporal and spatial developmental- and cell-type specific manner, and their loss or functional disruption results in unique phenotypic outcomes for the lens, and other ocular tissues. More recent work has found that different HS sulfation enzymes are also presented in a cell- and tissue-specific manner, and that disruption of these different sulfation patterns affects specific HS-protein interactions. Not surprisingly, these sulfated HS chains have also been reported to be required for lens and eye development, with dysregulation of HS chain structure and function leading to pathogenesis and eye-related phenotypes. In the lens, HSPGs undergo significant and specific changes in expression and function that can drive pathology, or in some cases, promote tissue repair. As master signalling regulators, HSPGs may one day serve as valuable biomarkers, and even as putative targets for the development of novel therapeutics, not only for the eye but for many other systemic pathologies.
Collapse
Affiliation(s)
- Tayler F L Wishart
- Molecular and Cellular Biomedicine, School of Medical Sciences, The University of Sydney, NSW, Australia.
| | - Frank J Lovicu
- Molecular and Cellular Biomedicine, School of Medical Sciences, The University of Sydney, NSW, Australia; Save Sight Institute, The University of Sydney, NSW, Australia.
| |
Collapse
|
2
|
Wishart TFL, Lovicu FJ. An Atlas of Heparan Sulfate Proteoglycans in the Postnatal Rat Lens. Invest Ophthalmol Vis Sci 2021; 62:5. [PMID: 34730792 PMCID: PMC8572486 DOI: 10.1167/iovs.62.14.5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Purpose The arrangement of lens cells is regulated by ocular growth factors. Although the effects of these inductive molecules on lens cell behavior (proliferation, survival, and fiber differentiation) are well-characterized, the precise mechanisms underlying the regulation of growth factor-mediated signaling in lens remains elusive. Increasing evidence highlights the importance of heparan sulfate proteoglycans (HSPGs) for the signaling regulation of growth factors; however, the identity of the different lens HSPGs and the specific roles they play in lens biology are still unknown. Methods Semiquantitative real-time (RT)‐PCR and immunolabeling were used to characterize the spatial distribution of all known HSPG core proteins and their associated glycosaminoglycans (heparan and chondroitin sulfate) in the postnatal rat lens. Fibroblast growth factor (FGF)-2-treated lens epithelial explants, cultured in the presence of Surfen (an inhibitor of heparan sulfate [HS]-growth factor binding interactions) were used to investigate the requirement for HS in FGF-2-induced proliferation, fiber differentiation, and ERK1/2-signaling. Results The lens expresses all HSPGs. These HSPGs are differentially localized to distinct functional regions of the lens. In vitro, inhibition of HS-sulfation with Surfen blocked FGF-2-mediated ERK1/2-signaling associated with lens epithelial cell proliferation and fiber differentiation, highlighting that these cellular processes are dependent on HS. Conclusions These findings support a requirement for HSPGs in FGF-2 driven lens cell proliferation and fiber differentiation. The identification of specific HSPG core proteins in key functional lens regions, and the divergent expression patterns of closely related HSPGs, suggests that different HSPGs may differentially regulate growth factor signaling networks leading to specific biological events involved in lens growth and maintenance.
Collapse
Affiliation(s)
- Tayler F L Wishart
- School of Medical Sciences, The University of Sydney, New South Wales, Australia
| | - Frank J Lovicu
- School of Medical Sciences, The University of Sydney, New South Wales, Australia.,Save Sight Institute, The University of Sydney, New South Wales, Australia
| |
Collapse
|
3
|
Shihan MH, Kanwar M, Wang Y, Jackson EE, Faranda AP, Duncan MK. Fibronectin has multifunctional roles in posterior capsular opacification (PCO). Matrix Biol 2020; 90:79-108. [PMID: 32173580 DOI: 10.1016/j.matbio.2020.02.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2019] [Revised: 02/10/2020] [Accepted: 02/25/2020] [Indexed: 12/26/2022]
Abstract
Fibrotic posterior capsular opacification (PCO), one of the major complications of cataract surgery, occurs when lens epithelial cells (LCs) left behind post cataract surgery (PCS) undergo epithelial to mesenchymal transition, migrate into the optical axis and produce opaque scar tissue. LCs left behind PCS robustly produce fibronectin, although its roles in fibrotic PCO are not known. In order to determine the function of fibronectin in PCO pathogenesis, we created mice lacking the fibronectin gene (FN conditional knock out -FNcKO) from the lens. While animals from this line have normal lenses, upon lens fiber cell removal which models cataract surgery, FNcKO LCs exhibit a greatly attenuated fibrotic response from 3 days PCS onward as assessed by a reduction in surgery-induced cell proliferation, and fibrotic extracellular matrix (ECM) production and deposition. This is correlated with less upregulation of Transforming Growth Factor β (TGFβ) and integrin signaling in FNcKO LCs PCS concomitant with sustained Bone Morphogenetic Protein (BMP) signaling and elevation of the epithelial cell marker E cadherin. Although the initial fibrotic response of FNcKO LCs was qualitatively normal at 48 h PCS as measured by the upregulation of fibrotic marker protein αSMA, RNA sequencing revealed that the fibrotic response was already quantitatively attenuated at this time, as measured by the upregulation of mRNAs encoding molecules that control, and are controlled by, TGFβ signaling, including many known markers of fibrosis. Most notably, gremlin-1, a known regulator of TGFβ superfamily signaling, was upregulated sharply in WT LCs PCS, while this response was attenuated in FNcKO LCs. As exogenous administration of either active TGFβ1 or gremlin-1 to FNcKO lens capsular bags rescued the attenuated fibrotic response of fibronectin null LCs PCS including the loss of SMAD2/3 phosphorylation, this suggests that fibronectin plays multifunctional roles in fibrotic PCO development.
Collapse
Affiliation(s)
- Mahbubul H Shihan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Mallika Kanwar
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Yan Wang
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Erin E Jackson
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Adam P Faranda
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | - Melinda K Duncan
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA.
| |
Collapse
|
4
|
Tekin K, Ozdamar Erol Y, Inanc M, Sargon MF, Cakar Ozdal P, Berker N. Ultrastructural Analysis of the Anterior Lens Epithelium in Cataracts Associated with Uveitis. Ophthalmic Res 2019; 63:213-221. [PMID: 31838467 DOI: 10.1159/000504497] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 10/31/2019] [Indexed: 12/14/2022]
Abstract
PURPOSE To investigate the transmission electron microscopic findings of lens epithelial cells (LECs) in patients with different subtypes of uveitis and to compare the findings with those in age-matched controls. METHODS In this prospective case-control study, the anterior lens capsules were taken from 47 eyes of 47 patients with uveitis of different subtypes (17 with Fuchs uveitis syndrome [FUS], 13 with -Behçet's uveitis, 10 with idiopathic uveitis, and 7 with herpetic keratouveitis) and from 15 eyes of 15 control patients. RESULTS In the FUS group, the LECs had homogeneous thickening and irregularity, with some small vacuoles and widespread, oval-shaped pigment clusters in some areas. In the Behçet uveitis group, there was evident thinning in the lens epithelium. The subepithelial tissue under the epithelium was thickened, and edematous areas were detected. In the idiopathic uveitis group, the LECs were thinner with small vacuoles, and the cubic structure of the LECs was transformed into a squamous one. Moreover, the LECs included some small vacuoles, similar to those in the FUS group. In the herpetic keratouveitis group, two prominent cell types were observed: (1) completely normal LECs and (2) degenerated-type LECs with pyknotic nuclei, condensation of chromatin, swelling in the cytoplasm, membrane ruptures, and intra-cytoplasmic inclusion bodies. In the control group, the LECs and all of their elements occurred in normal ultrastructural patterns, with the exception of a few small intraepithelial vacuoles, which were fewer in number and smaller than those in the FUS and idiopathic uveitis groups. CONCLUSION The electron microscopic analysis of LECs of patients with different subtypes of uveitis revealed significant ultrastructural alterations, which may be related to the summation of oxidative stress and intraocular inflammation.
Collapse
Affiliation(s)
- Kemal Tekin
- Ophthalmology Department, Ercis State Hospital, Van, Turkey,
| | - Yasemin Ozdamar Erol
- Ophthalmology Department, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | - Merve Inanc
- Ophthalmology Department, Ercis State Hospital, Van, Turkey
| | | | - Pinar Cakar Ozdal
- Ophthalmology Department, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | - Nilufer Berker
- Ophthalmology Department, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| |
Collapse
|
5
|
Tekin K, Erol YO, Sargon MF, Inanc M, Ozdal PC, Berker N. Effects of Fuchs uveitis syndrome on the ultrastructure of the anterior lens epithelium: A transmission electron microscopic study. Indian J Ophthalmol 2017; 65:1459-1464. [PMID: 29208835 PMCID: PMC5742983 DOI: 10.4103/ijo.ijo_691_17] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
PURPOSE The purpose of the study was to investigate the electron microscopic findings of the lens epithelial cells (LECs) in patients with Fuchs uveitis syndrome (FUS) who suffered from cataracts and to compare those with age-matched controls. METHODS This study was a prospective, comparative case series. The anterior lens capsules (ALC: basement membrane and associated LECs) were taken from 12 eyes of 12 cases of FUS and ten eyes of ten control patients. The ALCs were obtained from cataract surgery and prepared for transmission electron microscopy (TEM). RESULTS There were no statistically significant differences regarding the age or gender between the FUS group and the control group (P > 0.05). In the TEM examinations of the ALCs, all of the FUS cases revealed similar significant ultrastructural changes when compared to the control patients. In the FUS group, the LECs showed homogeneous thickening and irregularity which included some small vacuoles in different areas of the epithelial tissue. Moreover, in some areas of the LECs, widespread, oval-shaped, pigment clusters were detected. Conversely, in the control group, the LECs and all of their elements were in normal ultrastructural patterns, with the exception of some small intraepithelial vacuoles which were fewer and smaller than those in the FUS group. CONCLUSION Ultrastructural analysis of the ALC of the patients with FUS disclosed some significant alterations which may be related to the summation of oxidative stress, intraocular inflammation, and iris atrophy.
Collapse
Affiliation(s)
- Kemal Tekin
- Department of Ophthalmology, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | - Yasemin Ozdamar Erol
- Department of Ophthalmology, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | | | - Merve Inanc
- Department of Ophthalmology, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | - Pinar Cakar Ozdal
- Department of Ophthalmology, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| | - Nilufer Berker
- Department of Ophthalmology, Ulucanlar Eye Training and Research Hospital, Ankara, Turkey
| |
Collapse
|
6
|
Aose M, Linbo TH, Lawrence O, Senoo T, Raible DW, Clark JI. The occhiolino (occ) mutant Zebrafish, a model for development of the optical function in the biological lens. Dev Dyn 2017; 246:915-924. [PMID: 28422363 PMCID: PMC6800130 DOI: 10.1002/dvdy.24511] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 03/16/2017] [Accepted: 04/03/2017] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Zebrafish visual function depends on quality optics. An F3 screen for developmental mutations in the Zebrafish nervous system was conducted in wild-type (wt) AB Zebrafish exposed to 3 mM of N-ethyl-N-nitrosourea (ENU). RESULTS Mutant offspring, identified in an F3 screen, were characterized by a small pupil, resulting from retinal hypertrophy or hyperplasia and a small lens. Deficits in visual function made feeding difficult after hatching at approximately 5-6 days postfertilization (dpf). Special feeding conditions were necessary for survival of the occhiolino (occ) mutants after 6 dpf. Optokinetic response (OKR) tests measured defects in visual function in the occ mutant, although electroretinograms (ERGs) were normal in the mutant and wt. Consistent with the ERGs, histology found normal retinal structure in the occ mutant and wt Zebrafish. However, lens development was abnormal. Multiphoton imaging of the developmental stages of live embryos confirmed the formation of a secondary mass of lens cells in the developing eye of the mutant Zebrafish at 3-4 dpf, and laminin immunohistochemistry indicated the lens capsule was thin and disorganized in the mutant Zebrafish. CONCLUSIONS The occ Zebrafish is a novel disease model for visual defects associated with abnormal lens development. Developmental Dynamics 246:915-924, 2017. © 2017 Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Masamoto Aose
- Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan
| | - Tor H Linbo
- Department of Biological Structure, University of Washington, Seattle, Washington
| | - Owen Lawrence
- Department of Biological Structure, University of Washington, Seattle, Washington
| | - Tadashi Senoo
- Department of Ophthalmology, Dokkyo Medical University, Tochigi, Japan
| | - David W Raible
- Department of Biological Structure, University of Washington, Seattle, Washington
| | - John I Clark
- Department of Biological Structure, University of Washington, Seattle, Washington
- Department of Ophthalmology, University of Washington, Seattle, Washington
| |
Collapse
|
7
|
Tekin K, Erol YO, Inanc M, Sargon MF, Can CU, Polat S, Yilmazbas P. Electron microscopic evaluation of anterior lens epithelium in patients with idiopathic congenital cataract. Int Ophthalmol 2017; 38:2127-2132. [PMID: 28942547 DOI: 10.1007/s10792-017-0713-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 09/16/2017] [Indexed: 12/14/2022]
Abstract
PURPOSE To investigate the ultrastructure of the lens epithelial cells (LECs) in patients with idiopathic congenital cataract. METHODS This is a prospective interventional study. The anterior lens capsules (aLC: basement membrane and associated LECs) were taken from 16 eyes of 12 consecutive patients who were diagnosed as having idiopathic congenital cataracts. The aLCs were obtained from cataract surgery and prepared for transmission electron microscopy (TEM). RESULTS Some significant ultrastructural changes were observed in all aLCs of the participants. The anterior LECs showed alterations in different areas which were partly cuboidal and partly squamous in shape. The LECs had euchromatic nucleus and included some vacuoles in the cytoplasms as a remarkable alteration. The sizes of these intraepithelial cell vacuoles were changeable. CONCLUSIONS We identified remarkable changes in LECs of the eyes with idiopathic congenital cataract by TEM. It can be assumed that oxidative damage may be associated with these ultrastructural changes in LECs of the eyes with idiopathic congenital cataracts.
Collapse
Affiliation(s)
- Kemal Tekin
- Ankara Ulucanlar Eye Training and Research Hospital, 06240, Ankara, Turkey.
| | | | - Merve Inanc
- Ankara Ulucanlar Eye Training and Research Hospital, 06240, Ankara, Turkey
| | | | - Cigdem Ulku Can
- Ankara Ulucanlar Eye Training and Research Hospital, 06240, Ankara, Turkey
| | - Sibel Polat
- Ankara Ulucanlar Eye Training and Research Hospital, 06240, Ankara, Turkey
| | - Pelin Yilmazbas
- Ankara Ulucanlar Eye Training and Research Hospital, 06240, Ankara, Turkey
| |
Collapse
|
8
|
Barros RC, Gelens E, Bulten E, Tuin A, de Jong MR, Kuijer R, van Kooten TG. Self-assembled nanofiber coatings for controlling cell responses. J Biomed Mater Res A 2017; 105:2252-2265. [PMID: 28513985 DOI: 10.1002/jbm.a.36092] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/22/2017] [Accepted: 04/14/2017] [Indexed: 01/29/2023]
Abstract
Nanofibers are thought to enhance cell adhesion, growth, and function. We demonstrate that the choice of building blocks in self-assembling nanofiber systems can be used to control cell behavior. The use of 2 D-coated, self-assembled nanofibers in controlling lens epithelial cells, fibroblasts, and mesenchymal stem cells was investigated, focusing on gene and protein expression related to the fibrotic response. To this end, three nanofibers with different characteristics (morphology, topography, and wettability) were compared with two standard materials frequently used in culturing cells, TCPS, and a collagen type I coating. Cell metabolic activity, cell morphology, and gene and protein expression were analyzed. The most hydrophilic nanofiber with more compact network consisting of small fibers proved to provide a beneficial 2 D environment for cell proliferation and matrix formation while decreasing the fibrotic/stress behavior in all cell lines when compared with TCPS and the collagen type I coating. This nanofiber demonstrates the potential to be used as a biomimetic coating to study the development of fibrosis through epithelial-to-mesenchymal transition. This study also shows that nanofiber structures do not enhance cell function by definition, because the physico-chemical characteristics of the nanofibers influence cell behavior as well and actually can be used to regulate cell behavior toward suboptimal performance. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2252-2265, 2017.
Collapse
Affiliation(s)
- Raquel C Barros
- Department of Biomedical Engineering, University Medical Center Groningen (UMCG), University of Groningen, Hanzeplein 1, 9713, GZ Groningen, The Netherlands
| | - Edith Gelens
- Nano Fiber Matrices B.V. (Nano-FM), Zernikepark 6-8, Groningen, 9747 AN, The Netherlands
| | - Erna Bulten
- Nano Fiber Matrices B.V. (Nano-FM), Zernikepark 6-8, Groningen, 9747 AN, The Netherlands
| | - Annemarie Tuin
- Nano Fiber Matrices B.V. (Nano-FM), Zernikepark 6-8, Groningen, 9747 AN, The Netherlands
| | - Menno R de Jong
- Nano Fiber Matrices B.V. (Nano-FM), Zernikepark 6-8, Groningen, 9747 AN, The Netherlands
| | - Roel Kuijer
- Department of Biomedical Engineering, University Medical Center Groningen (UMCG), University of Groningen, Hanzeplein 1, 9713, GZ Groningen, The Netherlands
| | - Theo G van Kooten
- Department of Biomedical Engineering, University Medical Center Groningen (UMCG), University of Groningen, Hanzeplein 1, 9713, GZ Groningen, The Netherlands
| |
Collapse
|
9
|
Nibourg LM, Gelens E, Nibourg SAF, de Jong MR, Kuijer R, van Kooten TG, Koopmans SA. Effects of peptide ratios in nanofibre-based hydrogels for the prevention of capsular opacification. Acta Ophthalmol 2016; 94:721-729. [PMID: 27062370 DOI: 10.1111/aos.13047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 02/05/2016] [Indexed: 12/13/2022]
Abstract
PURPOSE To moderate the capsular opacification (CO) response after lens surgery, an experimental study was performed in which nanofibre-based hydrogels (nanogels) with different ratios of attached peptides were applied to provide extracellular matrix-related cues for lens epithelial cells (LECs) in a porcine eye model. METHODS The lens content was removed, and the capsules were refilled with nanogel. Lenses were divided into two groups, the first group (n = 34) was refilled with nanogels containing different ratios of two laminin-derived peptides (IKVAV + YIGSR), and the latter group (n = 26) was refilled with nanogel combinations of a fibronectin-derived and a type IV collagen-derived peptide (RGDS + DGEA). Two lenses were refilled with culture medium to investigate the effect of the medium on LECs. After refilling, lenses were extracted and cultured for 3 weeks. Lens epithelial cells (LECs) were assessed for morphology and alpha-smooth muscle actin (αSMA) expression using confocal laser scanning microscopy. RESULTS Differences were seen in cell morphology between lenses refilled with nanogels with IKVAV + YIGSR and RGDS + DGEA peptides. In nanogels with IKVAV + YIGSR peptides, differences in LEC morphology were largest when ratios between the peptides were unequal, whereas LEC responses from the RGDS + DGEA refilled groups showed variation in LEC morphology dependent on the total quantity of mixed-in peptides. The culture medium did not induce proliferation or transformation of LECs. CONCLUSIONS Ratios and concentrations of cell adhesion-mediating peptides both can direct the LEC response, depending on the adhesion molecules of origin, by influencing LEC proliferation and transformation. Nanogels with incorporated peptides may be tuned towards CO prevention.
Collapse
Affiliation(s)
- Lisanne M. Nibourg
- Department of Ophthalmology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
- Laboratory for Experimental Ophthalmology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
- W.J. Kolff Institute; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
| | | | - Simone A. F. Nibourg
- Department of Ophthalmology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
- Laboratory for Experimental Ophthalmology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
| | | | - Roel Kuijer
- W.J. Kolff Institute; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
- Department of Biomedical Engineering; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
| | - Theo G. van Kooten
- W.J. Kolff Institute; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
- Department of Biomedical Engineering; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
| | - Steven A. Koopmans
- Department of Ophthalmology; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
- W.J. Kolff Institute; University of Groningen, University Medical Center Groningen; Groningen The Netherlands
| |
Collapse
|
10
|
Intrinsic and extrinsic regulatory mechanisms are required to form and maintain a lens of the correct size and shape. Exp Eye Res 2016; 156:34-40. [PMID: 27109030 DOI: 10.1016/j.exer.2016.04.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 04/13/2016] [Accepted: 04/16/2016] [Indexed: 02/04/2023]
Abstract
Understanding how tissues and organs acquire and maintain an appropriate size and shape remains one of the most challenging areas in developmental biology. The eye lens represents an excellent system to provide insights into regulatory mechanisms because in addition to its relative simplicity in cellular composition (being made up of only two forms of cells, epithelial and fiber cells), these cells must become organized to generate the precise spheroidal arrangement that delivers normal lens function. Epithelial and fiber cells also represent spatially distinct proliferation and differentiation compartments, respectively, and an ongoing balance between these domains must be tightly regulated so that the lens achieves and maintains appropriate dimensions during growth and ageing. Recent research indicates that reciprocal inductive interactions mediated by Wnt-Frizzled and Notch-Jagged signaling pathways are important for maintaining and organizing these compartments. The Hippo-Yap pathway has also been implicated in maintaining the epithelial progenitor compartment and regulating growth processes. Thus, whilst some molecules and mechanisms have been identified, further work in this important area is needed to provide a clearer understanding of how lens size and shape is regulated.
Collapse
|
11
|
Nibourg LM, Gelens E, de Jong MR, Kuijer R, van Kooten TG, Koopmans SA. Nanofiber-based hydrogels with extracellular matrix-based synthetic peptides for the prevention of capsular opacification. Exp Eye Res 2015; 143:60-7. [PMID: 26474493 DOI: 10.1016/j.exer.2015.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/23/2015] [Accepted: 10/02/2015] [Indexed: 11/29/2022]
Abstract
Nanofiber-based hydrogels (nanogels) with different, covalently bound peptides were used as an extracellular environment for lens epithelial cells (LECs) in order to modulate the capsular opacification (CO) response after lens surgery in a porcine eye model. Lenses were divided into 15 groups (n = 4 per group), the lens content was removed and the empty capsules were refilled with nanogel without peptides and nanogels with 13 combinations of 5 different peptides: two laminin-derived, two fibronectin-derived, and one collagen IV-derived peptide representing cell adhesion motifs. A control group of 4 lenses was refilled with hyaluronan. After refilling, lenses were extracted from the porcine eye and cultured for three weeks. LECs were assessed for morphology and alpha smooth muscle actin (αSMA) expression using confocal laser scanning microscopy. Compared to hyaluronan controls, lenses filled with nanogel had less CO formation, indicated by a lower αSMA expression (P = 0.004). Microscopy showed differences in morphological cell response within the nanogel refilled groups. αSMA expression in these groups was highest in lenses refilled with nanogel without peptides (9.54 ± 11.29%). Overall, LEC transformation is reduced by the presence of nanogels and the response is improved even further by incorporation of extracellular matrix peptides representing adhesion motifs. Thus, nanomaterials targeting biological pathways, in our case interactions with integrin signaling, are a promising avenue toward reduction of CO. Further research is needed to optimize nanogel-peptide combinations that fully prevent CO.
Collapse
Affiliation(s)
- Lisanne M Nibourg
- University of Groningen, University Medical Center Groningen, Dept. of Ophthalmology, Hanzeplein 1, 9713 GZ Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Laboratory for Experimental Ophthalmology, Hanzeplein 1, 9713 GZ Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, W.J. Kolff Institute, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands.
| | - Edith Gelens
- Nano Fiber Matrices B.V., Zernikepark 6-8, 9747 AN Groningen, The Netherlands
| | - Menno R de Jong
- Nano Fiber Matrices B.V., Zernikepark 6-8, 9747 AN Groningen, The Netherlands
| | - Roel Kuijer
- University of Groningen, University Medical Center Groningen, W.J. Kolff Institute, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Dept. of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Theo G van Kooten
- University of Groningen, University Medical Center Groningen, W.J. Kolff Institute, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, Dept. of Biomedical Engineering, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| | - Steven A Koopmans
- University of Groningen, University Medical Center Groningen, Dept. of Ophthalmology, Hanzeplein 1, 9713 GZ Groningen, The Netherlands; University of Groningen, University Medical Center Groningen, W.J. Kolff Institute, Antonius Deusinglaan 1, 9713 AV Groningen, The Netherlands
| |
Collapse
|
12
|
Taylor L, Arnér K, Engelsberg K, Ghosh F. Scaffolding the retina: the interstitial extracellular matrix during rat retinal development. Int J Dev Neurosci 2015; 42:46-58. [PMID: 25758423 DOI: 10.1016/j.ijdevneu.2015.03.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/04/2015] [Accepted: 03/04/2015] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To examine the expression of interstitial extracellular matrix components and their role during retinal development. MATERIAL AND METHODS Fibronectin (FN), collagen IV (Coll IV) and laminin 5 (Lam 5) expression in rat retinas from developmental stages E17 to adult were studied. In addition, PN5 full-thickness retinas were cultured for 7 days with dispase, which selectively cleaves FN and Coll IV, at either 0.5 U/ml or 5.0 U/ml for 3 or 24h. Eyecups and retinal cultures were examined morphologically using hematoxylin and eosin staining and immunohistochemistry. RESULTS Coll IV, Lam 5 and FN were all transiently expressed in the interstitial matrix of the retinal layers during development. The retinal layers in dispase treated explants was severely disturbed in a dose and time dependent manner. CONCLUSIONS FN, Lam 5 and Coll IV, are present in the interstitial extracellular matrix during rat retinal development. Enzymatic cleavage of FN and Coll IV early in the lamination process disrupts the retinal layers implicating their pivotal role in this process.
Collapse
Affiliation(s)
- Linnéa Taylor
- Department of Ophthalmology, Lund University Hospital, Lund, Sweden.
| | - Karin Arnér
- Department of Ophthalmology, Lund University Hospital, Lund, Sweden
| | - Karl Engelsberg
- Department of Ophthalmology, Lund University Hospital, Lund, Sweden
| | - Fredrik Ghosh
- Department of Ophthalmology, Lund University Hospital, Lund, Sweden
| |
Collapse
|
13
|
Elemental analysis of sunflower cataract in Wilson's disease: a study using scanning transmission electron microscopy and energy dispersive spectroscopy. Exp Eye Res 2014; 121:58-65. [PMID: 24534570 DOI: 10.1016/j.exer.2014.02.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 02/04/2014] [Accepted: 02/06/2014] [Indexed: 11/22/2022]
Abstract
Signature ophthalmic characteristics of Wilson's disease (WD) are regarded as diagnostically important manifestations of the disease. Previous studies have proved the common occurrence of copper accumulation in the liver of patients with WD. However, in the case of sunflower cataracts, one of the rare diagnostic signs of WD, no study has demonstrated copper accumulation in the lens capsules of sunflower cataracts in WD patients. To investigate the nanostructure and elemental composition of sunflower cataracts in WD, transmission electron microscopy (TEM) was done on the capsulorhexised anterior lens capsule of sunflower cataracts in WD in order to evaluate anatomical variation and elemental changes. We utilized energy dispersive X-ray spectroscopy (EDS) to investigate the elemental composition of the lens capsule using both point and mapping spectroscopy. Quantitative analysis was performed for relative comparison of the elements. TEM showed the presence of granular deposits of varying size (20-350 nm), appearing mainly in the posterior one third of the anterior capsule. The deposits appeared in linear patterns with scattered dots. There were no electron-dense particles in the epithelial cell layer of the lens. Copper and sulfur peaks were consistently revealed in electron-dense granular deposits. In contrast, copper and sulfur peaks were absent in other tissues, including granule-free lens capsules and epithelial tissue. Most copper was exclusively located in clusters of electron-dense particles, and the copper distribution overlapped with sulfur on mapping spectroscopy. Quantitative analysis presented inconsistent ratios of copper to sulfur in each electron-dense granule. The mean ratio of copper to sulfur was about 3.25 (with a range of 2.39-3.78). This is the first elemental analysis of single electron particles in sunflower cataracts using EDS in the ophthalmic area. Sunflower cataracts with WD are assumed to be the result of accumulation of heterogeneous compounds composed of several materials, including copper, sulfur, and/or copper-binding proteins. Linear patterns of copper and sulfur deposition were detected in various sizes and composition ratios with these elements in cases of WD.
Collapse
|
14
|
Shimada A, Miyata Y, Kosano H. Type I collagen accelerates the spreading of lens epithelial cells through the expression and activation of matrix metalloproteinases. Curr Eye Res 2014; 39:460-71. [PMID: 24400880 DOI: 10.3109/02713683.2013.853194] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE Matrix metalloproteinases (MMPs) are involved in posterior capsule opacification (PCO), but the mechanisms that promote MMP expression are yet to be determined. In this study, we investigated whether type I collagen, which is only detected in aged or cataractous lens capsules, affects the expression and activation of MMPs in primary-cultured chicken lens epithelial cells (LECs). MATERIALS AND METHODS Chicken LECs were isolated from chicken embryos and cultured in Dulbecco's modified Eagle's medium containing 10% fetal bovine serum (FBS) on type I collagen-coated dishes. The activity of secreted MMPs was examined using gelatin zymography, and cell spreading was determined as the average area of randomly distributed cells. For some experiments, LECs were cultured in the presence of the broad-spectrum MMP inhibitor, GM6001. LECs cultured on uncoated dishes were used as controls. To examine the involvement of MMP in cell migration, a wound-healing assay was performed in the presence of the MMP inhibitor. RESULTS Chicken LECs constitutively express the pro-form of MMP-2. When LECs were cultured on type I collagen-coated dishes, they expressed the active form of MMP-2 and the pro-form of MMP-9. This expression and activation by type I collagen was also observed in the human LEC line SRA-01/04, but not the human Müller glial cell line, MIO-M1. Type I collagen enhanced cell spreading, which was suppressed by the MMP inhibitor. Type I collagen also accelerated α-smooth muscle actin expression. In addition, LEC migration was inhibited by the MMP inhibitor in a dose-dependent manner in the wound-healing assay. CONCLUSION Type I collagen promotes the expression and activation of MMPs in a LEC-specific manner. These results suggest that type I collagen may play a role in PCO development.
Collapse
Affiliation(s)
- Arata Shimada
- Faculty of Pharmaceutical Science, Teikyo University , Itabashi-ku, Tokyo , Japan
| | | | | |
Collapse
|
15
|
Hayes JM, Hartsock A, Clark BS, Napier HRL, Link BA, Gross JM. Integrin α5/fibronectin1 and focal adhesion kinase are required for lens fiber morphogenesis in zebrafish. Mol Biol Cell 2012; 23:4725-38. [PMID: 23097490 PMCID: PMC3521681 DOI: 10.1091/mbc.e12-09-0672] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Accepted: 10/16/2012] [Indexed: 11/16/2022] Open
Abstract
Lens fiber formation and morphogenesis requires a precise orchestration of cell- extracellular matrix (ECM) and cell-cell adhesive changes in order for a lens epithelial cell to adopt a lens fiber fate, morphology, and migratory ability. The cell-ECM interactions that mediate these processes are largely unknown, and here we demonstrate that fibronectin1 (Fn1), an ECM component, and integrin α5, its cellular binding partner, are required in the zebrafish lens for fiber morphogenesis. Mutations compromising either of these proteins lead to cataracts, characterized by defects in fiber adhesion, elongation, and packing. Loss of integrin α5/Fn1 does not affect the fate or viability of lens epithelial cells, nor does it affect the expression of differentiation markers expressed in lens fibers, although nucleus degradation is compromised. Analysis of the intracellular mediators of integrin α5/Fn1 activity focal adhesion kinase (FAK) and integrin-linked kinase (ILK) reveals that FAK, but not ILK, is also required for lens fiber morphogenesis. These results support a model in which lens fiber cells use integrin α5 to migrate along a Fn-containing substrate on the apical side of the lens epithelium and on the posterior lens capsule, likely activating an intracellular signaling cascade mediated by FAK in order to orchestrate the cytoskeletal changes in lens fibers that facilitate elongation, migration, and compaction.
Collapse
MESH Headings
- Animals
- Animals, Genetically Modified
- Embryo, Nonmammalian/embryology
- Embryo, Nonmammalian/metabolism
- Fibronectins/genetics
- Fibronectins/metabolism
- Focal Adhesion Kinase 1/genetics
- Focal Adhesion Kinase 1/metabolism
- Gene Expression Regulation, Developmental
- Gene Knockdown Techniques
- Immunohistochemistry
- In Situ Hybridization
- Integrin alpha5/genetics
- Integrin alpha5/metabolism
- Lens, Crystalline/embryology
- Lens, Crystalline/metabolism
- Lens, Crystalline/ultrastructure
- Luminescent Proteins/genetics
- Luminescent Proteins/metabolism
- Microscopy, Confocal
- Microscopy, Electron
- Models, Genetic
- Morphogenesis/genetics
- Mutation
- Zebrafish/embryology
- Zebrafish/genetics
- Zebrafish/metabolism
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism
Collapse
Affiliation(s)
- Julie M. Hayes
- Section of Molecular Cell and Developmental Biology and Institute for Cell and Molecular Biology, University of Texas at Austin, Austin, TX 78722
| | - Andrea Hartsock
- Section of Molecular Cell and Developmental Biology and Institute for Cell and Molecular Biology, University of Texas at Austin, Austin, TX 78722
| | - Brian S. Clark
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226-0509
| | - Hugh R. L. Napier
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226-0509
| | - Brian A. Link
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226-0509
| | - Jeffrey M. Gross
- Section of Molecular Cell and Developmental Biology and Institute for Cell and Molecular Biology, University of Texas at Austin, Austin, TX 78722
- Institute for Neuroscience, University of Texas at Austin, Austin, TX 78722
| |
Collapse
|
16
|
Sousounis K, Tsonis PA. Patterns of gene expression in microarrays and expressed sequence tags from normal and cataractous lenses. Hum Genomics 2012; 6:14. [PMID: 23244575 PMCID: PMC3563465 DOI: 10.1186/1479-7364-6-14] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 05/14/2012] [Indexed: 11/30/2022] Open
Abstract
In this contribution, we have examined the patterns of gene expression in normal and cataractous lenses as presented in five different papers using microarrays and expressed sequence tags. The purpose was to evaluate unique and common patterns of gene expression during development, aging and cataracts.
Collapse
Affiliation(s)
- Konstantinos Sousounis
- Department of Biology and Center for Tissue Regeneration and Engineering, University of Dayton, Dayton, OH 45469-2320, USA
| | | |
Collapse
|
17
|
Danysh BP, Czymmek KJ, Olurin PT, Sivak JG, Duncan MK. Contributions of mouse genetic background and age on anterior lens capsule thickness. Anat Rec (Hoboken) 2009; 291:1619-27. [PMID: 18951502 DOI: 10.1002/ar.20753] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Accurate lens capsule thickness measurements are necessary for studies investigating mechanical characteristics of the capsule. Confocal Z-axis imaging was used to measure the anterior lens capsule thickness of living intact lenses with minimal tissue manipulation. Measurements of the anterior capsule thickness is reported for the first time in young and old mice from four inbred strains, BALB/c, FVB/N, C57BL/6, and 129X1, and the outbred strain ICR. Our data demonstrates that the mouse anterior lens capsule continues to grow postnatally similar to that described in other mammals. It is also shown there is a significant difference in anterior lens capsule thickness between unrelated mouse strains, suggesting that capsule thickness is a quantitative trait shared by strains with common ancestry. Measurements, taken from other regions of FVB/N capsules revealed the anterior pole to be the thickest, followed by the equatorial region and posterior pole. In addition to mouse, anterior capsule measurements taken from intact cattle, rabbit, rat lenses, and human capsulotomy specimens correlated with the overall size of the animal.
Collapse
Affiliation(s)
- Brian P Danysh
- Department of Biological Sciences, University of Delaware, Newark, Delaware 19716, USA
| | | | | | | | | |
Collapse
|
18
|
Danysh BP, Duncan MK. The lens capsule. Exp Eye Res 2008; 88:151-64. [PMID: 18773892 DOI: 10.1016/j.exer.2008.08.002] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 07/24/2008] [Accepted: 08/01/2008] [Indexed: 01/28/2023]
Abstract
The lens capsule is a modified basement membrane that completely surrounds the ocular lens. It is known that this extracellular matrix is important for both the structure and biomechanics of the lens in addition to providing informational cues to maintain lens cell phenotype. This review covers the development and structure of the lens capsule, lens diseases associated with mutations in extracellular matrix genes and the role of the capsule in lens function including those proposed for visual accommodation, selective permeability to infectious agents, and cell signaling.
Collapse
Affiliation(s)
- Brian P Danysh
- Department of Biological Sciences, University of Delaware, Newark, DE 19716, USA
| | | |
Collapse
|
19
|
Walker J, Menko AS. Integrins in lens development and disease. Exp Eye Res 2008; 88:216-25. [PMID: 18671967 DOI: 10.1016/j.exer.2008.06.020] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2008] [Revised: 06/19/2008] [Accepted: 06/23/2008] [Indexed: 11/26/2022]
Abstract
Integrins are the major cell surface receptors for proteins in the extracellular matrix. These receptors form major cell signaling centers that are bidirectional, communicating messages between the cell and its environment. They are a large receptor family, with members well-known to regulate cellular processes essential to both development and disease. In this review we examine the literature regarding integrins in the lens. Here we cover integrin function in lens cell differentiation, in the development of the lens and in protection of the lens epithelial cell phenotype. In addition, we analyze the role of integrins in the progression of lens fibrotic diseases, focusing particularly on integrin regulation of TGFbeta signaling pathways in posterior capsule opacification (PCO) and anterior subcapsular cataract (ASC).
Collapse
Affiliation(s)
- Janice Walker
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | |
Collapse
|
20
|
Wederell ED, de Iongh RU. Extracellular matrix and integrin signaling in lens development and cataract. Semin Cell Dev Biol 2006; 17:759-76. [PMID: 17134921 DOI: 10.1016/j.semcdb.2006.10.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
During development of the vertebrate lens there are dynamic interactions between the extracellular matrix (ECM) of the lens capsule and lens cells. Disruption of the ECM causes perturbation of lens development and cataract. Similarly, changes in cell signaling can result in abnormal ECM and cataract. Integrins are key mediators of ECM signals and recent studies have documented distinct repertoires of integrin expression during lens development, and in anterior subcapsular cataract (ASC) and posterior caspsule opacification (PCO). Increasingly, studies are being directed to investigating the signaling pathways that integrins modulate and have identified Src, focal adhesion kinase (FAK) and integrin-linked kinase (ILK) as downstream kinases that mediate proliferation, differentiation and morphological changes in the lens during development and cataract formation.
Collapse
Affiliation(s)
- Elizabeth D Wederell
- Department of Anatomy & Histology, Save Sight Institute, University of Sydney, NSW 2006, Australia
| | | |
Collapse
|
21
|
Zinkevich NS, Bosenko DV, Link BA, Semina EV. laminin alpha 1 gene is essential for normal lens development in zebrafish. BMC DEVELOPMENTAL BIOLOGY 2006; 6:13. [PMID: 16522196 PMCID: PMC1450269 DOI: 10.1186/1471-213x-6-13] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/28/2005] [Accepted: 03/07/2006] [Indexed: 11/15/2022]
Abstract
Background Laminins represent major components of basement membranes and play various roles in embryonic and adult tissues. The functional laminin molecule consists of three chains, alpha, beta and gamma, encoded by separate genes. There are twelve different laminin genes identified in mammals to date that are highly homologous in their sequence but different in their tissue distribution. The laminin alpha -1 gene was shown to have the most restricted expression pattern with strong expression in ocular structures, particularly in the developing and mature lens. Results We identified the zebrafish lama1 gene encoding a 3075-amino acid protein (lama1) that possesses strong identity with the human LAMA1. Zebrafish lama1 transcripts were detected at all stages of embryo development with the highest levels of expression in the developing lens, somites, nervous and urogenital systems. Translation of the lama1 gene was inhibited using two non-overlapping morpholino oligomers that were complementary to sequences surrounding translation initiation. Morphant embryos exhibited an arrest in lens development and abnormalities in the body axis length and curvature. Conclusion These results underline the importance of the laminin alpha 1 for normal ocular development and provide a basis for further analysis of its developmental roles.
Collapse
Affiliation(s)
- Natalya S Zinkevich
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Departments of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Dmitry V Bosenko
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Departments of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Brian A Link
- Departments of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Elena V Semina
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Departments of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Departments of Human and Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| |
Collapse
|
22
|
Wederell ED, Brown H, O'connor M, Chamberlain CG, McAvoy JW, de Iongh RU. Laminin-binding integrins in rat lens morphogenesis and their regulation during fibre differentiation. Exp Eye Res 2005; 81:326-39. [PMID: 16129100 DOI: 10.1016/j.exer.2005.02.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2004] [Revised: 02/07/2005] [Accepted: 02/09/2005] [Indexed: 11/26/2022]
Abstract
Mammalian lens development involves cell-cell and cell-ECM interactions. As integrins are a major family of cell adhesion molecules, we examined the expression patterns of several integrin subunits (alpha3A, alpha3B, alpha6A, alpha6B, beta1 and beta4) during rat lens development. RT-PCR, in situ hybridisation, immunofluorescence and immunoblotting were used to investigate expression of integrin subunits during lens development and differentiation. RT-PCR showed expression of alpha3A, alpha6A, alpha6B and beta1A but not alpha3B or beta4 subunits in postnatal rat lenses. Each subunit displayed distinct spatio-temporal expression patterns. beta1 integrin was expressed in both epithelium and fibres. alpha3A subunit expression was restricted to the epithelium; expression ceased abruptly at the lens equator. Expression of the alpha6A subunit increased during fibre differentiation, whereas alpha6B expression was predominantly associated with epithelial cells during lens development. In lens epithelial explants, FGF induced some of the changes in integrin expression that are characteristic of fibre differentiation in vivo. One notable exception was the inability of FGF to reproduce the distinctive down-regulation of the alpha3 isoform that is associated with initiation of elongation in vivo. Interestingly, vitreous treatment was able to reproduce this shift in alpha3 expression indicating that another factor(s), in addition to FGF, may be required for full and complete transition from an epithelial cell to a fibre cell. Integrin subunit expression therefore appears to be highly regulated during lens development and fibre differentiation with evidence of major changes in alpha3 and alpha6 isoform expression. These results indicate that integrins may play important roles in development and growth of the lens. How specific integrin subunits influence the behaviour of cells in different developmental compartments of the lens remains to be determined.
Collapse
Affiliation(s)
- Elizabeth D Wederell
- Save Sight Institute and Department of Clinical Ophthalmology and Eye Health, The University of Sydney, NSW 2006, Australia; Department of Anatomy and Histology and Institute for Biomedical Research (F13), The University of Sydney, NSW 2006, Australia
| | | | | | | | | | | |
Collapse
|
23
|
Lovicu FJ, McAvoy JW. Growth factor regulation of lens development. Dev Biol 2005; 280:1-14. [PMID: 15766743 DOI: 10.1016/j.ydbio.2005.01.020] [Citation(s) in RCA: 262] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2004] [Revised: 01/05/2005] [Accepted: 01/13/2005] [Indexed: 02/01/2023]
Abstract
Lens arises from ectoderm situated next to the optic vesicles. By thickening and invaginating, the ectoderm forms the lens vesicle. Growth factors are key regulators of cell fate and behavior. Current evidence indicates that FGFs and BMPs are required to induce lens differentiation from ectoderm. In the lens vesicle, posterior cells elongate to form the primary fibers whereas anterior cells differentiate into epithelial cells. The divergent fates of these embryonic cells give the lens its distinctive polarity. There is now compelling evidence that, at least in mammals, FGF is required to initiate fiber differentiation and that progression of this complex process depends on the synchronized and integrated action of a number of distinct growth factor-induced signaling pathways. It is also proposed that an antero-posterior gradient of FGF stimulation in the mammalian eye ensures that the lens attains and maintains its polarity and growth patterns. Less is known about differentiation of the lens epithelium; however, recent studies point to a role for Wnt signaling. Multiple Wnts and their receptors are expressed in the lens epithelium, and mice with impaired Wnt signaling have a deficient epithelium. Recent studies also indicate that other families of molecules, that can modulate growth factor signaling, have a role in regulating the ordered growth and differentiation of the lens.
Collapse
Affiliation(s)
- F J Lovicu
- Save Sight Institute, University of Sydney, NSW, Australia
| | | |
Collapse
|
24
|
de Jong-Hesse Y, Kampmeier J, Lang GK, Lang GE. Effect of extracellular matrix on proliferation and differentiation of porcine lens epithelial cells. Graefes Arch Clin Exp Ophthalmol 2005; 243:695-700. [PMID: 15702326 DOI: 10.1007/s00417-004-1116-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2004] [Revised: 12/01/2004] [Accepted: 12/08/2004] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND Proliferation and differentiation of lens epithelial cells (LECs) are important mechanisms of secondary cataract formation. After extracapsular cataract extraction the extracellular matrix (ECM) around the remaining LECs is altered compared with the intact lens. This study investigated the effects of different ECMs on cell proliferation and alpha-smooth muscle actin (alpha-SMA) expression, a marker for myofibroblasts, in cultured porcine LECs. METHODS Porcine LECs were cultured for 3 days (cell proliferation assay) or 4 days (alpha-SMA expression) on wells and glass cover slips, respectively, coated with laminin, fibronectin, type I collagen or type IV collagen. LECs cultured on uncoated wells or cover slips served as control. Proliferative response was measured by [(3)H]-thymidine incorporation into DNA. alpha-SMA was detected immunocytochemically with a mouse monoclonal antibody, and the relative numbers of alpha-SMA-positive cells were calculated. Statistical analysis was performed using Student's unpaired t-test. RESULTS Cell proliferation was significantly increased by coating with fibronectin (10,320.5+/-6,073 counts per minute; p<0.0001) (mean +/- SD), type I collagen (12,507.3+/-3,914.2 CPM; p<0.0001) and type IV collagen (9,591.4+/-4,088 CPM; p<0.0001) compared with control (1,876.5+/-998 CPM), whereas coating with laminin had no effect (1,760.8+/-812.6 CPM; p=0.7271). The ratio of alpha-SMA-positive LECs cultured on uncoated cover slips for a period of 4 days was 12.2+/-3.51%. This ratio was significantly increased by coating with fibronectin (24.3+/-4.56%; p=0.0001) and type I collagen (21.2+/-8.48%; p=0.0142). Coating with laminin (9.8+/-3.67%; p=0.1682) and type IV collagen (9.0+/-7.09 %; p=0.2491) slightly decreased alpha-SMA expression, but this effect was not statistically significant. CONCLUSIONS Fibronectin and type I collagen stimulated both cell proliferation and alpha-SMA expression in cultured porcine LECs. Because fibronectin and type I collagen are not normally present in the adult lens, their possible introduction into the lens capsule after cataract surgery may play a critical role in the development of posterior capsule opacification.
Collapse
Affiliation(s)
- Yvonne de Jong-Hesse
- Department of Ophthalmology, University of Ulm, Prittwitzstrasse 43, 89075 Ulm, Germany
| | | | | | | |
Collapse
|
25
|
Evans MDM, Pavon-Djavid G, Hélary G, Legeais JM, Migonney V. Vitronectin is significant in the adhesion of lens epithelial cells to PMMA polymers. J Biomed Mater Res A 2004; 69:469-76. [PMID: 15127394 DOI: 10.1002/jbm.a.30017] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A major complication of intraocular lens surgery is diminished visual acuity caused by the regrowth of lens epithelial cells (secondary cataract). Polymethylmethacrylate (PMMA) is a commonly used intraocular lens material. This study addresses the mechanisms underlying the initial adhesion of lens epithelial cells to PMMA and a functionalized PMMA-based terpolymer known to inhibit cell proliferation. Rabbit lens epithelial cells were cultured on the test polymer surfaces in medium containing serum depleted of either fibronectin or vitronectin (or both) to identify the role of these proteins in the initial process of cell adhesion. Adherent cells were quantitated after 60 min, and the actin cytoskeleton and focal contact formation were compared in each serum treatment on both polymers. Vitronectin was significantly more effective for initial cell attachment to both polymers than fibronectin. Normal cell spreading on PMMA required vitronectin and was independent of fibronectin, whereas cell spreading on the terpolymer was abnormal and required the presence of fibronectin and vitronectin together. Together, these results help to explain the inhibition of cell proliferation previously shown on the functionalized PMMA. This work contributes to the design of a polymer for use in intraocular lenses that inhibits proliferation of the target cells.
Collapse
Affiliation(s)
- Margaret D M Evans
- CSIRO Molecular Science, 11 Julius Avenue, North Ryde, Sydney, NSW, Australia 2113.
| | | | | | | | | |
Collapse
|
26
|
Kim JT, Lee DH, Chung KH, Kang IC, Kim DS, Joo CK. Inhibitory effects of salmosin, a disintegrin, on posterior capsular opacification in vitro and in vivo. Exp Eye Res 2002; 74:585-94. [PMID: 12076080 DOI: 10.1006/exer.2001.1150] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The proliferation, migration and transdifferentiation of the remaining lens epithelial cells (LECs) after cataract surgery are a major cause of posterior capsular opacification (PCO). It has previously been reported that salmosin, a novel disintegrin, significantly inhibits solid tumor growth in mice by perturbation of tumor-specific angiogenesis via blocking alpha v beta 3 integrin expressed on vascular endothelial cells. In this study, the inhibitory function of salmosin in PCO was investigated and was found that salmosin inhibits the attachment of bovine LECs and rabbit lens cells (N/N1003A) to extracellular matrix-coated plates. The anti-adhesive activity of salmosin was approximately 1000 times higher than that of synthetic Arg-Gly-Asp peptide. In addition, the cell proliferation and migration of bovine LECs and N/N1003A were strongly inhibited by salmosin, whereas the proliferation of corneal endothelial cells was less affected. LEC migration and proliferation were also decreased by salmosin treatment in rabbit eyes without any toxic effect in the cornea, iris and retina. In this study, salmosin was shown to specifically inhibit LEC migration and proliferation in an animal model. Therefore, the authors suggest that further investigation may show salmosin to be a good candidate for inhibiting PCO development.
Collapse
Affiliation(s)
- Jong-Tak Kim
- Laboratory of Visual Science, College of Medicine, The Catholic University of Korea, and Catholic Research Institutes of Medical Science, Seoul, South Korea
| | | | | | | | | | | |
Collapse
|
27
|
Affiliation(s)
- I Michael Wormstone
- School of Biological Sciences, University of East Anglia, Norwich, NR4 7TJ, UK.
| |
Collapse
|
28
|
Oharazawa H, Ibaraki N, Lin LR, Reddy VN. The effects of extracellular matrix on cell attachment, proliferation and migration in a human lens epithelial cell line. Exp Eye Res 1999; 69:603-10. [PMID: 10620389 DOI: 10.1006/exer.1999.0723] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Lens capsule consists of several kinds of extracellular matrix (ECM) which may play an important role in cell attachment, migration and proliferation of lens epithelial cells as a basement membrane. We have investigated the effects of ECM on cell attachment, proliferation and migration in a human lens epithelial (HLE) cell line. The HLE cell line, SRA 01/04, which was transfected with large T-antigen of SV40 was cultured in the absence of serum. Culture plates were coated with human type IV collagen, laminin or fibronectin. The number of cells were counted at 30-180 min and 3, 5 and 7 days of culture. The rate of BrdU incorporation was measured to study the cell proliferation. The cell migration was measured 1, 3, 5 and 7 days after seeding cells. Integrins, the receptors of ECM, were also detected using antibodies for the cell membrane antigens (CD49b, CD49c, CD49e) by an immunohistochemical method. Although less than 10% of cells attached to the non-coated plate and 50-60% of cells attached to the ECM-coated plates, there was no difference of cell attachment among each ECM used. The cell attachment was almost complete during the first 30 min of culture. Cell proliferation was not enhanced, but cell survival was aided by culture on the ECM components for up to 7 days. The area of cell attachment enlarged on the ECM-coated plates, whereas no migration was observed on the non-coated plate. These data indicate that ECM is the essential factor for cell attachment and increases migration of HLE cells.
Collapse
Affiliation(s)
- H Oharazawa
- Department of Ophthalmology, Nippon Medical School, Tokyo, Japan
| | | | | | | |
Collapse
|
29
|
Kurosaka D, Kato K, Oshima T, Kurosaka H, Yoshino M, Ogata M. Extracellular matrixes influence alpha-smooth muscle actin expression in cultured porcine lens epithelial cells. Curr Eye Res 1999; 19:260-3. [PMID: 10487965 DOI: 10.1076/ceyr.19.3.260.5308] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE To determine whether extracellular matrix (ECM) influences the expression of alpha-smooth muscle actin (alpha-SMA), a marker for myofibroblasts, in cultured porcine lens epithelial cells (LECs). METHODS Porcine LECs were cultured for 6 days in an F-12 nutrient mixture supplemented with 5% fetal bovine serum on wells that were coated with laminin, fibronectin, type I collagen, or type IV collagen. LECs cultured on uncoated wells served as a control. Alpha-SMA was detected immunocytochemically with a mouse monoclonal antibody, and the ratio of the number of alpha-SMA-positive cells to the total number of cells, the P/T ratio, was calculated. RESULTS The P/T ratio of the LECs on the uncoated dishes was about 5%. LECs cultured on wells coated with laminin or type IV collagen significantly reduced the ratio, whereas fibronectin or type I collagen had no effect. CONCLUSIONS The ECM influences alpha-SMA expression in cultured porcine LECs.
Collapse
Affiliation(s)
- D Kurosaka
- Keio University School of Medicine Department of Ophthalmology Tokyo, Japan.
| | | | | | | | | | | |
Collapse
|
30
|
Abstract
The human eye is programmed to achieve emmetropia in youth and to maintain emmetropia with advancing years. This is despite the changes in all eye dimensions during the period of growth and the continuing growth of the lens throughout life. The process of emmetropisation in the child's eye is indicated by a shift from the Gaussian distribution of refractive errors around a hypermetropic mean value at birth to the non-Gaussian leptokurtosis around an emmetropic mean value in the adult. Emmetropisation is the result of both passive and active processes. The passive process is that of proportional enlargement of the eye in the child. The proportional enlargement of the eye reduces the power of the dioptric system in proportion to the increasing axial length. The power of the cornea is reduced by lengthening of the radius of curvature. The power of the lens is reduced by lengthening radii of curvature and the effectivity of the lens is reduced by deepening of the anterior chamber. Ametropia results when these changes are not proportional. The active mechanism involves the feedback of image focus information from the retina and consequent adjustment of the axial length. Defective image formation interferes with this feedback and ametropia then results. Heredity determines the tendency to certain globe proportions and environment plays a part in influencing the action of active emmetropisation. The maintenance of emmetropia in the adult in spite of continuing lens growth with increasing lens thickness and increasing lens curvature, which is known as the lens paradox, is due to the refractive index changes balancing the effect of the increased curvature. These changes may be due to the differences between nucleus and cortex or to gradient changes within the cortex.
Collapse
Affiliation(s)
- N P Brown
- Clinical Cataract Research Unit, Nuffield Laboratory of Ophthalmology, Oxford, UK
| | | | | |
Collapse
|
31
|
Walker JL, Menko AS. alpha6 Integrin is regulated with lens cell differentiation by linkage to the cytoskeleton and isoform switching. Dev Biol 1999; 210:497-511. [PMID: 10357906 DOI: 10.1006/dbio.1999.9277] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The developing chicken embryo lens provides a unique model for examining the relationship between alpha6 integrin expression and cell differentiation, since multiple stages of differentiation are expressed concurrently at one stage of development. We demonstrate that alpha6 integrin is likely to mediate the inductive effects of laminin on lens differentiation as well as to function in a matrix-independent manner along the cell-cell interfaces of the differentiating cortical lens fiber cells. Both alpha6 isoform expression and its linkage to the cytoskeleton were regulated in a differentiation-specific manner. The association of alpha6 integrin with the Triton-insoluble cytoskeleton increased as the lens cells differentiated, reaching its highest levels in the cortical fiber region where the lens fiber cells are formed. In this region of the lens alpha6 integrin was uniquely localized along the cell-cell borders of the differentiating fiber cells, similar to beta1. alpha6beta4, the primary transmembrane protein of hemidesmosomes, is also expressed in the lens, but in the absence of hemidesmosomes. Differential expression of alpha6A and alpha6B isoforms with lens cell differentiation was seen at both the mRNA and the protein levels. RT-PCR studies demonstrated that alpha6B was the predominant isoform expressed both early in development, embryonic day 4, and in the epithelial regions of the day 10 embryonic lens. Isoform switching, with alpha6A now the predominant isoform, occurred in the fiber cell zones. Immunoprecipitation studies showed that alpha6B, which is characteristic of undifferentiated cells, was expressed by the lens epithelial cells but was dramatically reduced in the lens fiber zones. Expression of alpha6B began to drop as the cells initiated their differentiation and then dropped precipitously in the cortical fiber zone. In contrast, expression of the alpha6A isoform remained high until the cells became terminally differentiated. alpha6A was the predominant isoform expressed in the cortical fiber region. The down-regulation of alpha6B relative to alpha6A provides a developmental switch in the process of lens fiber cell differentiation.
Collapse
Affiliation(s)
- J L Walker
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 571 Jefferson Alumni Hall, Philadelphia, Pennsylvania, 19107, USA
| | | |
Collapse
|
32
|
Richiert DM, Ireland ME. TGF-beta elicits fibronectin secretion and proliferation in cultured chick lens epithelial cells. Curr Eye Res 1999; 18:62-71. [PMID: 10075204 DOI: 10.1076/ceyr.18.1.62.5393] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE To determine if the cataract forming influence of TGF-beta on lens cells is due to its effects on the ECM. METHODS Primary cultures of chick lens annular pad cells were exposed to TGF-beta and various exogenously supplied components of the lens capsule. Proliferative response were measured through tritiated thymidine incorporation into DNA. Cell spreading accompanying increased matrix interactions and growth was monitored with phase contrast microscopy. ECM proteins were detected in culture media and as deposited matrices with Western blotting and silver staining. TGF-beta receptors were identified with Western blotting. RESULTS Chick lens cells were shown to express type I and II TGF-beta receptors. TGF-beta stimulated cell growth and ECM production particularly with regard to fibronectin. Fibronectin was secreted into the culture medium and deposited onto plastic substrates. Plating cells on ECM components found in the lens capsule further increased their growth in response to TGF-beta. CONCLUSIONS These results indicate that TGF-beta may have a normal function in the lens regulating capsular protein production. The potent stimulation of lens cell growth by TGF-beta may be due to mis-regulated production of lens capsular proteins not normally found in great abundance.
Collapse
Affiliation(s)
- D M Richiert
- Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | | |
Collapse
|
33
|
Marunouchi T, Hosoya H, Morioku T, Mori T, Majima Y, Kousaka M. Up-regulation of fibroblast growth factor receptor-1 in lens epithelial cells paralleled by growth stimulation. Exp Eye Res 1998; 67:611-6. [PMID: 9878224 DOI: 10.1006/exer.1998.0588] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
34
|
Oshika T, Nagata T, Ishii Y. Adhesion of lens capsule to intraocular lenses of polymethylmethacrylate, silicone, and acrylic foldable materials: an experimental study. Br J Ophthalmol 1998; 82:549-53. [PMID: 9713064 PMCID: PMC1722579 DOI: 10.1136/bjo.82.5.549] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIMS To investigate the adhesion characteristics of several intraocular lenses (IOLs) to the simulated and rabbit lens capsule. METHODS Adhesive force to bovine collagen sheets was measured in water with polymethylmethacrylate (PMMA), three piece silicone, and acrylic foldable IOLs. In rabbit eyes, phacoemulsification and IOL implantation were performed. Three weeks later, adhesion between the anterior/posterior capsules and IOL optic was tested, and the capsule was examined histologically. RESULTS The mean adhesive force to the collagen sheet was 1697 (SD 286) mg for acrylic foldable, 583 (49) mg for PMMA, and 0 mg for silicone IOLs (p = 0.0003, Kruskal-Wallis test). Scores (0-5) of adhesion between rabbit anterior capsule and IOL optic were 4.50 (0.55) for acrylic foldable, 3.20 (0.84) for PMMA, and 0.40 (0.55) for silicone IOLs (p = 0.004). Scores between rabbit posterior capsule and IOL optic displayed a similar tendency; 4.50 (0.84) for acrylic foldable, 3.00 (1.00) for PMMA, and 0.40 (0.55) for silicone IOLs (p = 0.021). Histological observation indicated that the edge of IOL optic suppressed the migration of lens epithelial cells towards the centre of the posterior capsule. This inhibitory effect was most pronounced with acrylic foldable IOL and least with silicone IOL. CONCLUSIONS The acrylic foldable IOL adhered to the lens capsule more than the PMMA IOL, and the silicone IOL showed no adhesiveness. These differences seem to play a role in preventing lens epithelial cells from migrating and forming posterior capsule opacification.
Collapse
Affiliation(s)
- T Oshika
- Department of Ophthalmology, University of Tokyo School of Medicine, Japan
| | | | | |
Collapse
|
35
|
Chamberlain CG, McAvoy JW. Fibre differentiation and polarity in the mammalian lens: a key role for FGF. Prog Retin Eye Res 1997. [DOI: 10.1016/s1350-9462(96)00034-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
36
|
Abstract
In this paper, the more recent literature pertaining to differentiation in the developing vertebrate lens is reviewed in relation to previous work. The literature reviewed reveals that the developing lens has been, and will continue to be, a useful model system for the examination of many fundamental processes occurring during embryonic development. Areas of lens development reviewed here include: the induction and early embryology of the lens; lens cell culture techniques; the role of growth factors and cytokines; the involvement of gap junctions in lens cell-cell communication; the role of cell adhesion molecules, integrins, and the extracellular matrix; the role of the cytoskeleton; the processes of programmed cell death (apoptosis) and lens fibre cell denucleation; the involvement of Pax and Homeobox genes; and crystallin gene regulation. Finally, some speculation is provided as to possible directions for further research in lens development.
Collapse
Affiliation(s)
- M A Wride
- Department of Physiology, University of Alberta, Edmonton, Canada
| |
Collapse
|
37
|
Pande MV, Spalton DJ, Marshall J. In vivo human lens epithelial cell proliferation on the anterior surface of PMMA intraocular lenses. Br J Ophthalmol 1996; 80:469-74. [PMID: 8695571 PMCID: PMC505501 DOI: 10.1136/bjo.80.5.469] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
AIMS To study in vivo human lens epithelial cell proliferation on the anterior surface of PMMA implants and its interaction with postoperative blood-aqueous barrier breakdown in eyes undergoing cataract surgery. METHODS A prospective study was carried out on three consecutive patient cohorts undergoing cataract surgery with intraocular lens implantation using three different surgical techniques which produce different anatomical relations between the implant and lens capsule. Specular microscopy of the anterior implant surface was used to document the natural history, topography, and density of lens epithelial cells and the laser flare and cell meter were used to measure postoperative blood-aqueous barrier breakdown. RESULTS All groups showed lens epithelial cell proliferation onto the anterior surface of PMMA implants. This was initiated by and restricted to the region of anterior capsule-implant contact and decreased with the onset of anterior capsular opacification. Significant correlation was found in all groups between lens epithelial cell proliferation and postoperative blood-aqueous barrier breakdown. CONCLUSIONS Human lens epithelial cell behaviour on PMMA surfaces in vivo differs from that seen in culture studies. Humoral factors in the aqueous, biomaterial properties of the implant, and its anatomical relations with the anterior and posterior lens capsule influence lens epithelial cell behaviour in vivo.
Collapse
Affiliation(s)
- M V Pande
- Department of Ophthalmology, St Thomas's Hospital, London
| | | | | |
Collapse
|
38
|
Harvey AR, Plant GW, Tan MM. Schwann cells and the regrowth of axons in the mammalian CNS: a review of transplantation studies in the rat visual system. Clin Exp Pharmacol Physiol 1995; 22:569-79. [PMID: 7586715 DOI: 10.1111/j.1440-1681.1995.tb02068.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
1. We have used peripheral nerve transplants or cultured Schwann cells grafted in association with different types of polymer to study axonal regrowth in the rat visual system. In some instances the glia were co-grafted with fetal tectal tissue. 2. The studies have two main aims: (i) to determine whether retinal axons can be induced to regrow at a site distant from their cell soma, that is, after damage to the brachial region of the optic tract; (ii) to determine whether retinal axons exposed to Schwann cells retain the ability to recognize their appropriate target neurons in CNS tissue. 3. In brachial lesion studies, Schwann cells were placed in the lesion site in association with nitrocellulose papers, within polycarbonate tubes in the presence or absence of a supporting extracellular matrix (ECM), or within polymer hydrogel scaffolds. Autologous sciatic nerve grafts were also used. Immunohistochemical studies revealed the presence of regenerating axons within all polymer bridges. Regrowth of retinal axons was also seen, however, growth was not extensive and was limited to the proximal 1-1.5 mm of the implants. 4. In target innervation experiments, two surgical paradigms were developed. In one experiment, a segment of sciatic nerve was autografted onto the transected optic nerve in adult rats and the distal end of each graft was placed adjacent to fetal tectal (target) tissue implanted into the frontal cortex. To date, we have not been able to demonstrate selective recognition of target regions within tectal transplants by retinal axons exiting the sciatic nerve implants. 5. In the second experiment, Schwann cells were mixed with fetal tectal cells and co-grafted to the midbrain of newborn host rats. Schwann cells altered the characteristic pattern of host retinal growth into tectal grafts; in some cases axons were induced to grow away from appropriate target areas by nearby co-grafted Schwann cells. 6. In summary, Schwann cell/polymer scaffolds may provide a useful way of promoting the regrowth of damaged axons in the CNS, however: (i) in adults, at least, their effectiveness is reduced if they are located at a distance from the cell bodies giving rise to regenerating axons; (ii) in some circumstances exposure to a peripheral glial environment may affect the capacity of regenerating axons to recognize appropriate target cells in the CNS neuropil.
Collapse
Affiliation(s)
- A R Harvey
- Department of Anatomy and Human Biology, The University of Western Australia, Nedlands, Perth, Australia
| | | | | |
Collapse
|
39
|
Kidd GL, Reddan JR, Russell P. Differentiation and angiogenic growth factor message in two mammalian lens epithelial cell lines. Differentiation 1994; 56:67-74. [PMID: 8026648 DOI: 10.1046/j.1432-0436.1994.56120067.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Lens epithelial cells in culture can sometimes be induced to form spheroid aggregates termed lentoid bodies, composed of cells exhibiting various characteristics of the more highly differentiated lens fiber cells. However, lentoid bodies are often slow to form, and the ability to produce them declines with serial subculture. It was therefore of interest to establish and/or characterize lens epithelial cell lines capable of forming lentoid bodies. The differentiation state was assessed in lentoid bodies formed by each of two lens epithelial cell lines, the transformed alpha TN4 cell line from mouse and the nontransformed N/N1135A cell line from rabbit. Lentoid and monolayer cultures of each cell line were examined for transcripts of the lens-specific alpha A-crystallin ("alpha A"), gamma D-crystallin ("gamma D"; formerly gamma 1-crystallin) and MP26 genes. alpha TN4 lentoid bodies contained 2.5 times the alpha A RNA found in monolayer cells, but lacked detectable gamma D and MP26 RNA. None of the three markers were detected in either lentoid or monolayer N/N1135A cultures grown under the conditions described. Lentoid body formation alone, therefore, does not indicate the extent of differentiation occurring. At least some of the changes in cell adhesion occurring during lentoid body formation involve laminin-like and fibronectin-like interactions, and are reminiscent of those observed during embryonic lens formation. Finally, vascular endothelial growth factor mRNA was absent from the lens but present in alpha TN4 cells, suggesting a mechanism whereby the lens tumors of the founder mouse became vascularized.
Collapse
Affiliation(s)
- G L Kidd
- Laboratory of Mechanisms of Ocular Disease, National Eye Institute, National Institutes of Health, Bethesda, MD 20892
| | | | | |
Collapse
|
40
|
|
41
|
Abstract
We have studied the survival requirements of developing lens epithelial cells to test the hypothesis that most cells are programmed to kill themselves unless they are continuously signaled by other cells not to do so. The lens cells survived for weeks in both explant cultures and high-density dissociated cell cultures in the absence of other cells or added serum or protein, suggesting that they do not require signals from other cell types to survive. When cultured at low density, however, they died by apoptosis, suggesting that they depend on other lens epithelial cells for their survival. Lens epithelial cells cultured at high density in agarose gels also survived for weeks, even though they were not in direct contact with one another, suggesting that they can promote one another's survival in the absence of cell-cell contact. Conditioned medium from high density cultures promoted the survival of cells cultured at low density, suggesting that lens epithelial cells support one another's survival by secreting survival factors. We show for the first time that normal cell death occurs within the anterior epithelium in the mature lens, but this death is strictly confined to the region of the anterior suture.
Collapse
Affiliation(s)
- Y Ishizaki
- Department of Biology, University College, London, United Kingdom
| | | | | | | |
Collapse
|
42
|
Schulz MW, Chamberlain CG, de Iongh RU, McAvoy JW. Acidic and basic FGF in ocular media and lens: implications for lens polarity and growth patterns. Development 1993; 118:117-26. [PMID: 7690700 DOI: 10.1242/dev.118.1.117] [Citation(s) in RCA: 100] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We have shown previously that FGF induces lens epithelial cells in explant culture to proliferate, migrate and differentiate into fibre cells in a progressive concentration-dependent manner. In situ, these processes occur in a distinct anterior-posterior pattern in clearly defined regions of the lens. Thus anterior-posterior differences in the bio-availability of FGF in the lens environment may play a role in determining lens polarity and growth patterns. In this study, using heparin chromatography and western blotting (or ELISA), we established that both acidic and basic FGF are present in the aqueous and vitreous (the ocular media that bathe the anterior and posterior compartments of the lens, respectively). In addition, substantially more FGF was recovered from vitreous than from aqueous. Both forms of FGF were also detected in lens fibre cells and capsule. A truncated form of basic FGF (less than 20 × 10(3) M(r)) predominated in every case with traces of higher M(r) forms in lens cells. For acidic FGF, the classical full-length form (about 20 × 10(3) M(r)) predominated in lens cells and a truncated form was found in vitreous. The capsule contained a higher M(r) form. Using our explant system, we also tested the biological activity of ocular media and FGF fractions obtained from vitreous and lens cells. Vitreous but not aqueous contained fibre-differentiating activity. Furthermore, virtually all the fibre-differentiating activity of vitreous was shown to be FGF-associated, as follows: (a) this activity remained associated with FGF during fractionation of vitreous by heparin and Mono-S chromatography and (b) the activity of the major FGF-containing fraction was blocked by antibodies to acidic and basic FGF. Posterior, but not anterior, capsule was shown to have mitogenic activity, which was neutralised by FGF antibodies and associated only with the cellular surface. These results support our hypothesis that FGF is involved in determining the behaviour of lens cells in situ. In particular, a key role for FGF in determining lens polarity and growth patterns is suggested by the anterior-posterior differences in the bio-availability of FGF in the ocular media and capsule.
Collapse
Affiliation(s)
- M W Schulz
- Department of Anatomy and Histology, University of Sydney, NSW Australia
| | | | | | | |
Collapse
|