This proposal will test the hypothesis that glutamatergic signaling orchestrates early stages of granule cell development necessary for proper cerebellar circuit formation. Glutamate, which has a conserved signaling function across phyla, controls multiple intracellular signaling pathways through diverse receptors. Glutamate receptor expression in the brain is tightly developmentally regulated, suggesting specific functions of each receptor subtype at different stages of cell development. Indeed, emerging evidence implicates glutamate receptors in brain development. However, our understanding of such functions lags behind the known diversity of glutamate receptor subtypes. Previous and preliminary data suggest that granule cell precursors (GCPs) transiently express functional GluK2-containing kainate receptors (KAR) and group I metabotropic glutamate receptor 5 (mGlu5R) in the external germinal layer (EGL) when they exit the cell cycle and extend axons. However, it is not known whether, and if so how, gain or loss of function in GluK2 receptor and mGlu5R alters GCP development. In this proposal, Aim 1 and Aim 2 will examine the function of GluK2 and mGlu5R on GCP proliferation and axon extension, respectively.
Aim 3 will explore whether Bergmann glial cells, a specialized astrocytes extending processes through the EGL, release glutamate controlling GCP cell-cycle exit through mGlu5R. We will use a combination of time- lapse confocal microscopy (for calcium imaging, migration, and axon extension) in acute slices and in vivo approaches (drugs, RNA interference via electroporation, and genetic manipulation) in wild-type and transgenic mice, including mGlu5Rfl/fl (fl, floxed) and GluK2- knockout (KO).

Public Health Relevance

This proposal focuses on understanding the function of GluK2 and metabotropic glutamate receptor 5 (mGlu5R) on the early stages of granule cell development necessary for proper cerebellar circuit formation. One of the most important reasons for pursuing this line of investigation is that the GluK2 gene (GRIK2) and mGlu5R gene (GRM5) have been linked with neurodevelopmental disorders, in particular autism spectrum disorder and schizophrenia, and individuals with such disorders have abnormalities in cerebellar size and circuitry that are thought to contribute to some of the behavioral impairments.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS062731-04
Application #
8451453
Study Section
Cellular and Molecular Biology of Glia Study Section (CMBG)
Program Officer
Owens, David F
Project Start
2010-05-01
Project End
2015-04-30
Budget Start
2013-05-01
Budget End
2014-04-30
Support Year
4
Fiscal Year
2013
Total Cost
$342,373
Indirect Cost
$135,501
Name
Yale University
Department
Neurosurgery
Type
Schools of Medicine
DUNS #
043207562
City
New Haven
State
CT
Country
United States
Zip Code
06520
Gipson, Keith E; Rosinski, David J; Schonberger, Robert B et al. (2014) Elimination of gaseous microemboli from cardiopulmonary bypass using hypobaric oxygenation. Ann Thorac Surg 97:879-86
Feliciano, David M; Lin, Tiffany V; Hartman, Nathaniel W et al. (2013) A circuitry and biochemical basis for tuberous sclerosis symptoms: from epilepsy to neurocognitive deficits. Int J Dev Neurosci 31:667-78
Kubera, C; Hernandez, A L; Heng, V et al. (2012) Transient mGlu5R inhibition enhances the survival of granule cell precursors in the neonatal cerebellum. Neuroscience 219:271-9
Young, Stephanie Z; Taylor, M Morgan; Bordey, Angelique (2011) Neurotransmitters couple brain activity to subventricular zone neurogenesis. Eur J Neurosci 33:1123-32