Biophysical Cues, Antioxidants, and Trabecular Meshwork

The capacity of trabecular meshwork cells to resist oxidative stress is reduced in glaucoma. Research to investigate this loss in protection of the cells has disregarded the importance of biophysical cues in contributing to the antioxidant status. This study examines the contribution of nanoscale surface features and biomechanics to the total antioxidant status of these cells.

Trabecular meshwork cells are responsible for controlling intraocular pressure. Oxidative damage has recently been shown to be a factor in glaucoma. The proposed research will investigate how these cells are affected by the physical properties of the surface on which they are grown in terms of their ability to prepare for, and respond to, oxidative stress (i.e., free radical damage). We will determine both the “at-rest” antioxidant status of these cells, as well as how varying physical cues affect the response of trabecular meshwork cells to oxidative stress.

Specific Aims

Biophysical cues affect antioxidant status of trabecular meshwork cells. We will grow trabecular meshwork cells on surfaces with a variety of patterns (in the submicron to nanoscale range) and stiffnesses, mimicking that of the normal and glaucomatous states. We will determine the levels of antioxidant protection, as well as levels of oxidative damage to the DNA of the cells.

Biophysical cues improve the ability of trabecular meshwork cells to recover from oxidant stress. Using similar surfaces, we will apply oxidative stress to trabecular meshwork cells, and compare the recovery of the cells to those grown on conventional surfaces.

Benefit to Public

Glaucoma is a devastating and blinding disease, estimated to affect almost 80 million people by 2020. Much remains unknown about its initiation and progression, and current treatments are limited. We have discovered numerous relevant effects of surface physical properties on trabecular meshwork cells, including antioxidant status, and there is mounting evidence that oxidative damage is involved in glaucoma. This research will contribute significantly to the overall understanding of the mechanisms of glaucoma, which may eventually facilitate the development of new therapies.

Innovation

The vast majority of cell culture research is carried out using rigid surfaces that do not approximate the environment that the cells would experience in the body. To our knowledge, we are the only laboratory using biologically relevant surfaces in the submicron to nanoscale range to study human trabecular meshwork cells. Our previous studies have demonstrated numerous effects of surface characteristics on these cells in both health and disease, and this is the first study that would investigate the effect on antioxidant status.

Progress Updates

Dr. Russell’s and Dr. Reilly’s team is determining how changes in the physical environment influence the response of the trabecular meshwork (TM) cells to oxidative stress. The team has previously shown that the tissues and cells that regulate intraocular pressure, including the TM cells, become stiffer with glaucoma. Using TM cells in culture, they determined how changes in substrate stiffness and substrate topography at microscopic levels (nano- to submicron scale) influence cellular response to oxidative stress.

The team has discovered that the antioxidant capacity of TM cells is increased when they are cultured on patterned surfaces of specific size scales. They are currently quantifying the damage done by oxidative stress to the TM cells’ mitochondria (the cell’s source of energy). They have shown that biophysical cues are not recognized by the cell when a mechanism induced by oxidative stress is used to protect certain messages for protein synthesis.

This past year, the team has focused their attention on two proteins influenced by oxidative stress. These proteins are able to signal very dynamic processes inside the cells. Several of the changes influenced by these proteins produce characteristic alterations that are observed in the trabecular meshwork from eyes with glaucoma. They have shown that characteristics of the substrate (compliance and topography) are important determinants of the responses of these two proteins. The team is currently using corticosteroid treatment along with biophysical cues to simulate glaucoma, as well as treatment with Latrunculin B (an anti-glaucoma drug candidate), to assess the overall action of these proteins. These studies hopefully will lead to new targets for therapeutic drug development.