title: Effects of moderate and deep hypothermia on RNA-binding proteins RBM3 and CIRP expressions in murine hippocampal brain slices.
abstract: Therapeutic hypothermia has emerged as an effective neuroprotective therapy for cardiac arrest survivors. There are a number of purported mechanisms for therapeutic hypothermia, but the exact mechanism still remains to be elucidated. Although hypothermia generally down-regulates protein synthesis and metabolism in mammalian cells, a small subset of homologous (>70%) cold-shock proteins (RNA-binding motif protein 3, RBM3 and cold-inducible RNA-binding protein, CIRP) are induced under these conditions. In addition, RBM3 up-regulation in neuronal cells has recently been implicated in hypothermia-induced neuroprotection. Therefore, we compared the effects of moderate (33.5°C) and deep (17°C) hypothermia with normothermia (37°C) on the regulation of RBM3 and CIRP expressions in murine organotypic hippocampal slice cultures (OHSC), hippocampal neuronal cells (HT-22), and microglia cells (BV-2). Moderate hypothermia resulted in significant up-regulation of both RBM3 and CIRP mRNA in murine OHSC, but deep hyporthermia did not. RBM3 protein regulation was also significantly up-regulated by 33.5°C, but no significant up-regulation of CIRP protein was observed in the OHSC. Additionally, OHSC exposed to 17°C for 24h were positive for Propidium Iodide (PI) immunostaining, indicating the onset of cell death. Similarly, RBM3 gene expression in a HT-22 neuronal cells mono-culture and direct co-culture of HT-22 neuronal cells with BV-2 microglia cells were also up-regulated at 33.5°C but only in the co-culture at 17°C. No significant up-regulation of RBM3 nor CIRP gene expression were observed in a BV-2 mono-culture at either temperature. We observed that RBM3 mRNA and protein expressions in murine OHSC, as well as in mono-culture of HT-22 neuronal cells and direct co-culture of HT-22 neuronal cells with BV-2 microglia cells were significantly up-regulated by exposure to moderate hypothermia. These findings further support the implication of RBM3 as a potential effector for hypothermia-induced neuroprotection.
authors: Department of Congenital Heart Disease/Pediatric Cardiology, German Heart Institute Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. giang.tong@charite.de
authors: Giang
authors: G
authors: Tong
authors: Stefanie
authors: S
authors: Endersfelder
authors: Lisa-Maria
authors: LM
authors: Rosenthal
authors: Sonja
authors: S
authors: Wollersheim
authors: Igor Maximilian
authors: IM
authors: Sauer
authors: Christoph
authors: C
authors: Bührer
authors: Felix
authors: F
authors: Berger
authors: Katharina Rose Luise
authors: KR
authors: Schmitt
mesh_terms: D000818:Animals; D002460:Cell Line; D018920:Coculture Techniques; D006624:Hippocampus / Q000378:metabolism*; D007036:Hypothermia, Induced; D015151:Immunoblotting; D051379:Mice; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000378:metabolism; D009474:Neurons / Q000378:metabolism; D009924:Organ Culture Techniques; D016601:RNA-Binding Proteins / Q000096:biosynthesis*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: C106176:Cirbp protein, mouse; D016601:RNA-Binding Proteins; C484384:Rbm3 protein, mouse