Purchase this article with an account.
R. M. Beverley, M. J. Nolan, R. D. McCarty, B. Y. J. T. Yue, L. Qi, J. R. Samples, P. A. Knepper; Omega-3 Protects Trabecular Meshwork From Metabolic Stress. Invest. Ophthalmol. Vis. Sci. 2009;50(13):4866.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Supplemental dietary omega-3 fatty acid reduces IOP in rats and is neuroprotective against oxidative stress in retinal pigment epithelial cells. The omega-3 fatty acid docosahexaenoic acid (DHA) is an important omega-3 representing a large component of total acyl chains in nervous tissue and is concentrated in lipid rafts. The purpose of this study was to determine whether trabecular meshwork (TM) cell survival is influenced by DHA and the effects of DHA on caveolin/lipid rafts.
Primary cultures of human TM cells were pre-treated with 0.67, 2.01 and 6.03 µM DHA for 24 hrs and then challenged with metabolic stress using 1, 10 and 40 mM lactate for 3 hrs. Cell viability was determined. Lipid rafts in cell lysates were separated by an Optiprep density gradient (Sigma D1556). The preparation was centrifuged at 200,000 x g for 18 hrs; nine 1.0 ml fractions were pipetted from the top (lightest) to bottom (heaviest). Each fraction was analyzed for protein content, resolved by SDS polyacrylamide electrophoresis, and immunoblotted with anti-caveolin-1, anti-caveolin-2, and LRP-6 antibodies.
There was a statistically significant dose dependent increase in cell survival of TM cells subjected to lactate stress following DHA treatment; 0.67 µM pretreatment was insignificant, 2.01 µM pretreatment was significant (P<0.03), and 6.03 µM pretreatment was highly significant (P<0.001). The distribution of 22-kDa caveolin-1 in DHA-treated TM cells was markedly increased in fractions 1, 2, 4, and 5 compared to controls. The distribution of caveolin-2 in DHA-treated cells was increased in fractions 1 and 2, presumably forming homo- and heterodimers with caveolin-1. LRP-6 was strongly upregulated in fractions 3, 4, 5, and 6 compared to controls.
DHA treatment increased cell viability and changed caveolin-1, caveolin-2, and LRP-6 density gradient distribution in TM cells subjected to metabolic stress. These results indicate that DHA modulates the distribution and content of caveolin/lipid rafts which may play an important role in TM cell viability and cell signaling.
This PDF is available to Subscribers Only