Regulation of Myocilin-Associated Exosome Release from Human Trabecular Meshwork Cells
Open Access
- 1 March 2009
- journal article
- research article
- Published by Association for Research in Vision and Ophthalmology (ARVO) in Investigative Ophthalmology & Visual Science
- Vol. 50 (3), 1313-1318
- https://doi.org/10.1167/iovs.08-2326
Abstract
Purpose. The goal of the present study was to determine whether the release of exosomes containing MYOC from trabecular meshwork (TM) cells is constitutive or regulated. methods. Conditioned media from TM cells were analyzed for MYOC-associated exosomes after treatment with IFN-γ, porcine aqueous humor, dexamethasone, or a calcium ionophore in cells pretreated with dexamethasone. Aqueous humor was tested whole or fractionated by size exclusion filters. Exosomes from conditioned media were purified by differential centrifugation. Proteins in whole, exosome, and soluble fractions were separated by SDS-PAGE and analyzed for MYOC content by Western blot and densitometry. results. Although treatment of TM cells with IFN-γ increased the appearance of extracellular MYOC-associated exosomes, results were not significantly different from those of control (P = 0.13). In contrast, treatment with dexamethasone increased the appearance of MYOC in the exosome fraction by 376% (P < 0.01). The increase in MYOC-associated exosomes caused by dexamethasone was enhanced by an additional 379% after short-term exposure to ionomycin (P < 0.05). When cultured in media containing aqueous humor, MYOC-associated exosomes increased 514% over control (P < 0.01). Such an increase was diminished in cells treated with aqueous humor that was first passed through a 3-kDa or a 30-kDa, but not a 100-kDa, size exclusion filter. conclusions. The appearance of MYOC-associated exosomes in conditioned media from human TM cells is regulated by a corticosteroid, a calcium ionophore, and a component of aqueous humor, suggesting that TM cells respond to environmental cues by releasing MYOC-associated exosomes.This publication has 47 references indexed in Scilit:
- Mutant Myocilin Nonsecretion In Vivo Is Not Sufficient To Cause GlaucomaMolecular and Cellular Biology, 2006
- The identification of myocilin-associated proteins in the human trabecular meshworkExperimental Eye Research, 2006
- Identification of flotillin-1 as a protein interacting with myocilin: Implications for the pathogenesis of primary open-angle glaucomaBiochemical and Biophysical Research Communications, 2005
- Interaction of Myocilin with γ-Synuclein Affects Its Secretion and AggregationCellular and Molecular Neurobiology, 2005
- Extracellular Trafficking of Myocilin in Human Trabecular Meshwork CellsOnline Journal of Public Health Informatics, 2005
- Primary Trabecular Meshwork Cells Incubated in Human Aqueous Humor Differ from Cells Incubated in Serum SupplementsInvestigative Ophthalmology & Visual Science, 2005
- Myocilin binding to Hep II domain of fibronectin inhibits cell spreading and incorporation of paxillin into focal adhesionsExperimental Cell Research, 2005
- Rab11 Promotes Docking and Fusion of Multivesicular Bodies in a Calcium‐Dependent MannerTraffic, 2004
- Modulation of myocilin/TIGR expression in human trabecular meshwork.1999
- Isolation, culture, and characterization of endothelial cells from Schlemm's canal.1998