The overall aim of this proposal is to understand the mechanisms underlying glucose transport into neurons, a process vital in meeting energy requirements necessary for neuronal development and neurotransmission. GLUT 3, a specific facilitative glucose transporter is the predominant neuronal isoform that meets the high demand of these specialized cells. We have observed that GLUT 3 is transcriptionally regulated by cis-elements that bind Spl/Sp3, CREB, and MSY-1 trans-activating factors under normal development and HIF-1 -alpha and CREB under hypoxia. To pursue an in-vivo extension of these novel in-vitro observations, we have created a GLUT 3-luciferase transgenic mouse. Further to investigate the functional significance of GLUT 3, we created a GLUT 3 null mouse. The GLUT 3 null heterozygote demonstrates hypoxic-ischemia induced seizures and neuronal apoptosis earlier than the wild type mice. To define the role of neuronal GLUT 3 during development and in postnatal hypoxic-ischemia, the proximate goal of this proposal is to test the hypothesis that GLUT 3 expression is critical for neuronal glucose supply through development and hypoxic-ischemia. To test this hypothesis, we propose three specific aims: 1] To determine the mechanism(s) by which development and hypoxic-ischemia increase neuronal GLUT 3 expression, we plan to employ the GLUT 3-luciferase transgenic mouse lines and investigate the effect of normal development and hypoxic-ischemia on transcriptional regulation of GLUT 3, 2] To explore the effect of decreased GLUT 3 concentrations on normal neuronal development and in response to hypoxic-ischemic injury, we will employ the GLUT 3 null heterozygous mouse line (50%), and determine the effect on neuronal phenotype and function, and 3] To investigate the effect of absent GLUT 3 on normal neuronal development and following hypoxic-ischemic injury, we will ablate neuronal GLUT 3 expression by producing conditional (temporal and neuron-specific) GLUT 3 deficient mice, and examine the effect on neuronal phenotype. Our proposed studies will define the biological role of GLUT 3 during neurodevelopment and hypoxic-ischemic brain injury. The results of our proposed studies will provide novel insights into mechanisms responsible for neurodevelopmental disorders, thereby setting the stage for future development of innovative interventions.
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