Visual impairment in an optineurin mouse model of primary open-angle glaucoma

Primary open angle glaucoma (POAG) is characterized by progressive neurodegeneration of retinal ganglion cells (RGCs). Why RGCs degenerate in low pressure POAG remains poorly understood. To gain mechanistic insights, we developed a novel mouse model based on a mutation in human optineurin associated with hereditary, low-pressure POAG. This mouse improves the design and phenotype of currently available optineurin mice, which showed high global overexpression. While both 18-month old optineurin and nontransgenic control mice showed an age-related decrease in healthy axons and RGCs, the expression of mutant optineurin enhanced axonal degeneration and decreased RGC survival. Mouse visual function was determined using visual evoked potentials, which revealed specific visual impairment in contrast sensitivity. The E50K optineurin transgenic mouse described here exhibited clinical features of POAG, and may be useful for mechanistic dissection of POAG and therapeutic development

The characterization of calmodulin-integrated polyethylene glycol diacrylate hydrogels using the model protein GB1

Polyethylene glycol diacrylate (PEGDA) conjugated protein hydrogels are a promising new biomaterial for use in protein preservation and delivery. We have characterized the ability of a PEGDA-calmodulin hydrogel conjugate to bind, preserve and release an M13-tagged model protein, the B1 domain from streptococcus protein G (GB1). We used solution-state nuclear magnetic resonance (NMR) spectroscopy to examine the response of the hydrogel to thermal and desiccation stress. Our data shows that the PEGDA-calmodulin hydrogel can bind the M13-tagged GB1 without significantly disturbing the structure of the model protein. Addition of the calcium chelator, EGTA, disrupts the interaction between calmodulin and the M13 tag, resulting in the release of the protein from the hydrogel. We found that the PEGDA-calmodulin hydrogel provided little thermal stabilization of the protein when compared to the complex in solution. In addition, the hydrogel retained the model protein through desiccation and re-hydration, as well as its ability to release the protein upon addition of EGTA. Finally, when IgG was soaked into the gels, GB1 bound IgG and both IgG and GB1 were released with the addition of EGTA. These results demonstrate that calmodulin PEGDA hydrogels are a viable protein immobilization tool capable of preserving proteins and protein function

Visual impairment in an optineurin mouse model of primary open-angle glaucoma.

Primary open-angle glaucoma (POAG) is characterized by progressive neurodegeneration of retinal ganglion cells (RGCs). Why RGCs degenerate in low-pressure POAG remains poorly understood. To gain mechanistic insights, we developed a novel mouse model based on a mutation in human optineurin associated with hereditary, low-pressure POAG. This mouse improves the design and phenotype of currently available optineurin mice, which showed high global overexpression. Although both 18-month-old optineurin and nontransgenic control mice showed an age-related decrease in healthy axons and RGCs, the expression of mutant optineurin enhanced axonal degeneration and decreased RGC survival. Mouse visual function was determined using visual evoked potentials, which revealed specific visual impairment in contrast sensitivity. The E50K optineurin transgenic mouse described here exhibited clinical features of POAG and may be useful for mechanistic dissection of POAG and therapeutic development. Neurobiol Aging 2015 Jun; 36(6):2201-12