title: Complete transglutaminase 2 ablation results in reduced stroke volumes and astrocytes that exhibit increased survival in response to ischemia.
abstract: Transglutaminase 2 (TG2) is a very multifunctional protein that is ubiquitously expressed in the body. It is a Ca(2+)-dependent transamidating enzyme, a GTPase, as well as a scaffolding protein. TG2 is the predominant form of transglutaminase expressed in the mammalian nervous system. Previously, it was shown that TG2 can affect both cell death and cell survival mechanisms depending on the cell type and the stressor. In the case of ischemic stress, TG2 was previously shown to play a protective role in the models used. For example in hTG2 transgenic mice, where TG2 is overexpressed only in neurons, middle cerebral artery ligation (MCAL) resulted in smaller infarct volumes compared to wild type mice. In this study TG2 knock out mice were used to determine how endogenous TG2 affected stroke volumes. Intriguingly, infarct volumes in TG2 knock out mice were significantly smaller compared to wild type mice. As expected, primary neurons isolated from TG2 knock out mice showed decreased viability in response to oxygen-glucose deprivation. However, primary astrocytes that were isolated from TG2 knock out mice were resistant to oxygen-glucose deprivation in situ. Both wild type and knock out neurons were protected against oxygen glucose deprivation when they were co-cultured with astrocytes from TG2 knockout mice. Therefore, the decreased stroke volumes observed in TG2 knock out mice after MCAL, can be correlated with the protective effects of TG2 knock out in astrocytes in response to oxygen glucose deprivation in situ. These findings suggest that neuron-astrocyte crosstalk plays a significant role in mediating ischemic cell death and that TG2 differentially impacts cell survival depending on cell context.
authors.affiliation: Department of Pharmacology and Physiology, 601 Elmwood Avenue, Box 711, University of Rochester, Rochester, NY 14642, USA.
authors.forename: Gozde
authors.initials: G
authors.lastname: Colak
authors.forename: Gail V W
authors.initials: GV
authors.lastname: Johnson
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D001921:Brain / Q000473:pathology*; D002470:Cell Survival; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology; D018920:Coculture Techniques / Q000379:methods; D004195:Disease Models, Animal; D007839:Functional Laterality; D019204:GTP-Binding Proteins / Q000172:deficiency* / Q000235:genetics; D005786:Gene Expression Regulation / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000235:genetics / Q000473:pathology* / Q000503:physiopathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009474:Neurons / Q000502:physiology; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D012333:RNA, Messenger / Q000378:metabolism; D013318:Stroke Volume / Q000235:genetics*; D014162:Transfection; D011503:Transglutaminases / Q000172:deficiency* / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D012333:RNA, Messenger; D025521:Tumor Suppressor Proteins; D042461:Vascular Endothelial Growth Factor A; D049452:Green Fluorescent Proteins; D000091345:Protein Glutamine gamma Glutamyltransferase 2; D011503:Transglutaminases; D019204:GTP-Binding Proteins