title: The nuclear splicing factor RNA binding motif 5 promotes caspase activation in human neuronal cells, and increases after traumatic brain injury in mice.
abstract: Splicing factors (SFs) coordinate nuclear intron/exon splicing of RNA. Splicing factor disturbances can cause cell death. RNA binding motif 5 (RBM5) and 10 (RBM10) promote apoptosis in cancer cells by activating detrimental alternative splicing of key death/survival genes. The role(s) of RBM5/10 in neurons has not been established. Here, we report that RBM5 knockdown in human neuronal cells decreases caspase activation by staurosporine. In contrast, RBM10 knockdown augments caspase activation. To determine whether brain injury alters RBM signaling, we measured RBM5/10 protein in mouse cortical/hippocampus homogenates after controlled cortical impact (CCI) traumatic brain injury (TBI) plus hemorrhagic shock (CCI+HS). The RBM5/10 staining was higher 48 to 72 hours after injury and appeared to be increased in neuronal nuclei of the hippocampus. We also measured levels of other nuclear SFs known to be essential for cellular viability and report that splicing factor 1 (SF1) but not splicing factor 3A (SF3A) decreased 4 to 72 hours after injury. Finally, we confirm that RBM5/10 regulate protein expression of several target genes including caspase-2, cellular FLICE-like inhibitory protein (c-FLIP), LETM1 Domain-Containing Protein 1 (LETMD1), and amyloid precursor-like protein 2 (APLP2) in neuronal cells. Knockdown of RBM5 appeared to increase expression of c-FLIP(s), LETMD1, and APLP2 but decrease caspase-2.
authors.affiliation: Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Travis C
authors.initials: TC
authors.lastname: Jackson
authors.affiliation: Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Lina
authors.initials: L
authors.lastname: Du
authors.affiliation: Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Keri
authors.initials: K
authors.lastname: Janesko-Feldman
authors.affiliation: Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Vincent A
authors.initials: VA
authors.lastname: Vagni
authors.affiliation: Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Cameron
authors.initials: C
authors.lastname: Dezfulian
authors.affiliation: Pharmaceutical Sciences Department, University of Pittsburgh School of Pharmacy, Pittsburgh, Pennsylvania, USA.
authors.forename: Samuel M
authors.initials: SM
authors.lastname: Poloyac
authors.affiliation: Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Edwin K
authors.initials: EK
authors.lastname: Jackson
authors.affiliation: Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Robert S B
authors.initials: RS
authors.lastname: Clark
authors.affiliation: Department of Critical Care Medicine, Safar Center for Resuscitation Research, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Kochanek
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism / Q000473:pathology*; D001930:Brain Injuries / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D020169:Caspases / Q000378:metabolism*; D018797:Cell Cycle Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002478:Cells, Cultured; D004268:DNA-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D055785:Gene Knockdown Techniques; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000378:metabolism / Q000473:pathology*; D016601:RNA-Binding Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C512260:RBM10 protein, human; C531317:RBM10 protein, mouse; C473448:RBM5 protein, human; C585457:RBM5 protein, mouse; D016601:RNA-Binding Proteins; D025521:Tumor Suppressor Proteins; D020169:Caspases