The astroglial transporter GLT-1/EAAT2 is responsible for the largest percentage of glutamate transport in forebrain. Abnormal expression/function of EAAT2 is common to sporadic ALS, to transgenic models of the disease, as well as other neurological injuries. The mechanism that underlies transporter deregulation is not fully understood, but may involve altered promoter activation. We hypothesize that regulating expression of these proteins could provide powerful therapies to retard disease progression. Initial studies provide exciting evidence that increasing EAAT2 protein/activity can retard neurodegeneration in ALS animal models; diminish seizures associated with epilepsy, and retard brain tumor growth. In this proposal we will use recently generated GLT1 and GLAST-promoter reporter mice to evaluate the regulation of transporters. These rodents will be used to study the dysregulation of transporters in neurodegenerative disease. We propose to alter transporter gene activation as a novel means to delay neurodegenerative disease. The completion of these studies will provide a comprehensive understanding of transporter regulation in normal and abnormal CNS and their potential as neuroprotectants. Specifically we propose: 1) To understand the normal regional and temporal regulation of astroglial glutamate transporter gene expression, thru analysis of GLAST-BAC and GLT1-BAC promoter reporter expressing transgenic mice; 2) To test the hypothesis that altered glutamate transporter expression in neurological injury is the result of promoter deregulation; 3) To determine if altered cellular expression of astroglial glutamate transporters can prevent neuronal degeneration. Using drugs capable of increasing GLT1 and GLAST promoter expression we will determine if increased expression of the astroglial transporter(s) can prevent neural injury in vivo and we will determine if cell specific expression of glutamate transport alters chronic neurodegeneration using an animal model of amyotrophic lateral sclerosis. We hypothesize that over expression of GLT1 or GLAST will be neuroprotective in disease models. Over all Significance: In this proposal, we will develop a basic understanding of expression of GLAST and GLT I, discover reagents that can alter glutamate transporter activity, and determine if these approaches are useful for chronic neurological insults. ? ?
