Morphological and Functional Characterization of GPR109A in Mammalian Retina

Abstract

Vision is considered as one of the most important of the five human senses. This was reflected by a poll that was based on human psychology that revealed that the fear of losing vision is much higher than the fear of losing any of the other senses (Leo et al., 1999). Diabetic retinopathy (DR) is a leading cause of blindness worldwide. Diabetic retinopathy is defined as damage to retina caused by the complications of diabetes. Hyperglycemia is a major factor in the pathogenesis of diabetic retinopathy (Davis et al., 1998). The diabetes-induced metabolic and physiologic abnormalities in the retina are consistent with chronic inflammation (Kern et al., 2007). G-protein coupled receptors (GPCRs) comprise a large protein family of transmembrane receptors that play central roles in several biological processes (Wettschureck and Offermanns, 2005). GPCRs have the ability to bind to chemically distinct ligands, and as such are widely used as targets for pharmaceuticals aimed at treating pain, inflammation, and a broad spectrum of diseases (Vassilatis et al., 2003; Offermanns et al., 2006). GPR109A is a newly discovered Grlinked GPCR known for its anti-lipidemic and anti-inflammatory properties in several cell types. Here, my major goal was to study the expression and functional role of GPR109A in retina an its relevance to diabetes-associated retinal implications.