Article Text
Abstract
Aim: To test the hypothesis that trabecular meshwork endothelial cells (TMEs) increase the permeability of Schlemm’s canal endothelial cells (SCEs) by actively releasing ligands that modulate the barrier properties of SCEs.
Methods: The TMEs were first irradiated with a laser light and allowed to condition the medium, which is then added to SCEs. The treatment response is determined by both measuring SCE permeability (flow meters) and the differential expression of genes (Affymetrix chips and quantitative polymerase chain reaction (PCR)). The cytokines secreted by the treated cells were identified using ELISA and the ability of these cytokines to increase permeability is tested directly after their addition to SCEs in perfusion experiments.
Results: SCEs exposed to medium conditioned by the light activated TMEs (TME-cm) respond by undergoing a differential expression (DE) of 1120 genes relative to controls. This response is intense relative to a DE of only 12 genes in lasered SCEs. The TME-cm treatment of SCEs increased the SCE permeability fourfold. The role of cytokines in these responses is supported by two findings: adding specific cytokines established to be secreted by lasered TMEs to SCEs increases permeability; and inactivating the TME-cm by boiling or diluting, abrogates these conditioned media permeability effects.
Conclusion: These experiments show that TMEs can regulate SCE permeability and that it is likely that TMEs have a major role in the regulation of aqueous outflow. This novel TME driven cellular mechanism has important implications for the pathogenesis of glaucoma and the mechanism of action of laser trabeculoplasty. Ligands identified as regulating SCE permeability have potential use for glaucoma therapy.
- CAOP, conventional aqueous outflow pathway
- DE, differential expression
- DEGs, differentially expressed genes
- ELISA, enzyme linked immunosorbent assay
- F-D N:Y, frequency doubled, Q switched Nd:YAG
- IL, interleukin
- IOP, intraocular pressure
- PCR, polymerase chain reaction
- POAG, primary open angle glaucoma
- RMA, robust multiarray average
- SCEs, Schlemm’s canal endothelial cells
- TMEs, trabecular meshwork endothelial cells
- TNF, tumour necrosis factor
- endothelial cell interactions
- permeability
- gene expression
- cytokines
- glaucoma
- CAOP, conventional aqueous outflow pathway
- DE, differential expression
- DEGs, differentially expressed genes
- ELISA, enzyme linked immunosorbent assay
- F-D N:Y, frequency doubled, Q switched Nd:YAG
- IL, interleukin
- IOP, intraocular pressure
- PCR, polymerase chain reaction
- POAG, primary open angle glaucoma
- RMA, robust multiarray average
- SCEs, Schlemm’s canal endothelial cells
- TMEs, trabecular meshwork endothelial cells
- TNF, tumour necrosis factor
- endothelial cell interactions
- permeability
- gene expression
- cytokines
- glaucoma
Statistics from Altmetric.com
- CAOP, conventional aqueous outflow pathway
- DE, differential expression
- DEGs, differentially expressed genes
- ELISA, enzyme linked immunosorbent assay
- F-D N:Y, frequency doubled, Q switched Nd:YAG
- IL, interleukin
- IOP, intraocular pressure
- PCR, polymerase chain reaction
- POAG, primary open angle glaucoma
- RMA, robust multiarray average
- SCEs, Schlemm’s canal endothelial cells
- TMEs, trabecular meshwork endothelial cells
- TNF, tumour necrosis factor
- endothelial cell interactions
- permeability
- gene expression
- cytokines
- glaucoma
- CAOP, conventional aqueous outflow pathway
- DE, differential expression
- DEGs, differentially expressed genes
- ELISA, enzyme linked immunosorbent assay
- F-D N:Y, frequency doubled, Q switched Nd:YAG
- IL, interleukin
- IOP, intraocular pressure
- PCR, polymerase chain reaction
- POAG, primary open angle glaucoma
- RMA, robust multiarray average
- SCEs, Schlemm’s canal endothelial cells
- TMEs, trabecular meshwork endothelial cells
- TNF, tumour necrosis factor
- endothelial cell interactions
- permeability
- gene expression
- cytokines
- glaucoma
Footnotes
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This paper was presented at the Annual Meeting of the American Ophthalmological Society (AOS) in Sea Island, Ga, USA on 24 May 2005 and will be published digitally in the Proceedings of the AOS in December 2005. For the unabridged presentation of this paper see the BJO Online website. All work was performed at the University of California San Francisco, CA, USA.
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