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Show COLLEGE OF ENGINEERING UNDERGRADUATE RESEARCH ABSTRACTS Marsa Taheri John A. White CHANGES IN METABOTROPIC GLUTAMATE RECEPTOR 5 EXPRESSION IN ASTROCYTES FOLLOWING THEILER VIRUS INFECTION OF C57BL/6 MICE Marsa Taheri, (J. Michael Gee, John A. White) Department of Bioengineering University of Utah Acquired epilepsy, caused by prior neurological injuries such as viral infection of the central nervous system, contributes to almost half of all epilepsy cases. A prevalent form of acquired epilepsy is temporal lobe epilepsy (TLE), which is often resistant to available drugs. Although the molecular mechanisms underlying human TLE are largely unknown, evidence shows that astrocytes (the predominant glial cell type in the brain) are likely to be involved in epileptogenesis-the process by which a healthy brain becomes epileptic. Metabotropic glutamate receptor 5 (mGluR5) in astrocytes is thought to be particularly important in inducing excessive astrocytic Ca+2 signaling, which may lead to neuronal hyperexcitability associated with epilepsy. The goal of our study is to better understand the role that astrocytes, and particularly astrocytic mGluR5s, play in epileptogenesis. For this study, w e examined the Theiler's murine encephalomyelitis virus (TMEV)-induced seizure model in C57BI/6 mice during the latent period, in which epileptogenesis occurs. W e used immunohistochemistry, confocal microscopy, and image processing techniques to quantify the expression levels of astrocytic mGluR5 and to detect astrocyte morphological changes as determined by the expression of GFAP (glial fibrillary acidic protein). In brain slices obtained from two TMEV-injected mice and one control mouse w e found increased GFAP expression and morphology modifications in hippocampal astrocytes as well as increased mGluR5 expression in these astrocytes. While more animals are needed to determine the significance of our results, these findings suggest that changes in astrocyte mGluR5 expression may be an important factor in the development of behavioral seizures in epilepsy. Figure 1. GFAP (green) and mGluR5 (red) expression in the hippocampus of the control mouse and TMEV-injected mouse. Astrocyte morphology has changed in theTMEV model: GFAP expression has increased and astrocytes have overlapping domains (top images). Astrocyte mGluR5 expression in theTMEV model has also increased (bottom images). |