Metabolic Regulation by Mechanistic Target of Rapamycin in the Retinal Pigment Epithelium

Every morning when we open our eyes to see the world around us, the neurons in our retina begin to work.  Their intense workload demands high energy.  The retinal neurons rely on their supporting cells, such as retinal pigment epithelium (RPE) cells, to provide them with the fuel to meet their energy needs.  In this project, we will study the mechanisms of energy production and regulation, in both healthy and diseased eyes, particularly those with AMD.

Grantee institution at the time of this grant: The University of Texas Medical Branch at Galveston

The retinal pigment epithelium (RPE) is a layer of cells next to the retina that are metabolically coupled to the retina’s photoreceptor neurons.  In age-related macular degeneration (AMD), functional interactions between the two types of cells are disturbed, which will result in both defects in energy metabolism and inefficient removal of metabolic intermediates in the outer retina.  Limited information is available for metabolic profiles of eye tissues, and the mechanistic links between RPE metabolomics and retinal degeneration are yet to be determined.

Mechanistic target of rapamycin (mTOR) is a key regulatory protein that controls the balance between cellular anabolism and catabolism.  We recently found that abnormally high activity of mTOR leads to degeneration of the RPE and retina.  The current project will use high-resolution mass spectrometry-based metabolomics approaches to measure temporal and spatial changes of metabolic pathways in the RPE and retina under both physiological and disease conditions, with a focus on mTOR-mediated signal transduction pathways.  The findings from our proposed studies will further define how the RPE supports the photoreceptor functions via metabolic coupling, and hopefully identify novel druggable targets for preventing RPE and retinal degeneration during AMD.