UNIQUE LABELING PATTERN OF KYNURENINE AMINOTRANSFERASE-2 IN THE CEREBELLUM OF MICE
Emma Balog1, Gyula Jenei1, Levente Gellért1, Etsuro Ono2, József Toldi1, László Vécsei3, 4, Zsolt Kis1
2 Department of Biomedicine, Graduate School of Medical Sciences, Kyushu University Fukuoka, Japan; Center of Biomedical Research, Research Center for Human Disease Modeling, Graduate School of Medical Sciences, Kyushu University Fukuoka, Japan
Introduction: Kynurenic acid (KYNA) is one of the neuroactive end-products of the kynurenine pathway (KP) of tryptophan (TRP) degradation in the mammalian brain. Alone or jointly, these effects probably play an important role in the mechanism of neuroprotective and neuromodulatory effects of endogenous KYNA in the central nervous system. Up to now, four aminotransferases have been shown to catalyze the transamination of the pivotal KP metabolite L-kynurenine to KYNA. Out of four isoforms of KAT enzymes, KAT-2 is of greatest importance both in the murine and human brain. KAT-2 related studies were focused to different parts of forebrain, but not to the cerebellum. To our best knowledge, there is no description of KAT-2 immunohistochemistry in cerebellum of mice. Aims: The aim of this study was to investigate the possible localization of KAT-2 enzyme in the cerebellum of mice: is there any sign of KAT-2 enzyme in the cerebellum; if yes, is it localized in glial cells and/or in neurons; in what kind of cells? Methods: for the experiments we used brain slices of C57Bl/6 mice after transcardial perfusion. Fluorescent immunohistochemistry was performed using indirect immunolabeling. Results: High levels of KAT-2 expression were found throughout the cerebellum in several types of neurons. Cells with the highest levels of KAT-2 expression were identified as Purkinje cells. In contrast to the other forebrain areas, no glial localization of the enzyme was observed in the cerebellum. Conclusions: KAT-2 is only expressed in neurons in the cerebellum and not in glia. Acknowledgments: This study was supported by grant GINOP 2.3.2-15-2016-00034 and co-financed by EFOP-3.6.1-16-2016-00008 grant and grant by MTA-SZTE Neuroscience Research group.