Effects of AAV-mediated knockdown of nNOS and GPx-1 gene expression in rat hippocampus after traumatic brain injury

• Published in: PloS one 2017-10, Vol.12 (10), p.e0185943-e0185943
• Main Authors: Boone, Deborah R, Leek, Jeanna M, Falduto, Michael T, Torres, Karen E O, Sell, Stacy L, Parsley, Margaret A, Cowart, Jeremy C, Uchida, Tatsuo, Micci, Maria-Adelaide, DeWitt, Douglas S, Prough, Donald S, Hellmich, Helen L
• Format: Article
• Language: English
• Subjects: Anesthesiology; Animals; Biology and life sciences; Brain; Brain injuries; Brain Injuries, Traumatic - genetics; Brain Injuries, Traumatic - metabolism; Brain Injuries, Traumatic - physiopathology; Brain research; Care and treatment; Cells (biology); Cognitive ability; Dependovirus - genetics; Dependovirus - metabolism; DNA microarrays; Gene expression; Gene Expression Profiling; Gene Knockdown Techniques; Gene therapy; Genes; Genetic aspects; Genetic engineering; Genomics; Glutathione; Glutathione peroxidase; Glutathione Peroxidase - antagonists & inhibitors; Glutathione Peroxidase - genetics; Glutathione Peroxidase - metabolism; Head injuries; Hippocampus; Hippocampus - metabolism; Hippocampus - physiopathology; Immunological memory; Laser Capture Microdissection; Male; Maze Learning; Medicine and Health Sciences; Memory; Memory Disorders - genetics; Memory Disorders - metabolism; Memory Disorders - physiopathology; Memory, Short-Term - physiology; Metabolic Networks and Pathways - genetics; Microarray Analysis; Neural stem cells; Neural Stem Cells - cytology; Neural Stem Cells - metabolism; Neurodegeneration; Neurons; Neurons - metabolism; Neurons - pathology; Nitric oxide; Nitric Oxide Synthase Type I - antagonists & inhibitors; Nitric Oxide Synthase Type I - genetics; Nitric Oxide Synthase Type I - metabolism; Nitric-oxide synthase; Pathogenesis; Percussion; Peroxidase; Physiological aspects; Rats; Rats, Sprague-Dawley; Ribonucleic acid; RNA; RNA Interference; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; RNA-mediated interference; Rodents; Short term memory; Signal Transduction; siRNA; Sleep; Studies; Traumatic brain injury; Viruses
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0185943

Virally mediated RNA interference (RNAi) to knock down injury-induced genes could improve functional outcome after traumatic brain injury (TBI); however, little is known about the consequences of gene knockdown on downstream cell signaling pathways and how RNAi influences neurodegeneration and behavior. Here, we assessed the effects of adeno-associated virus (AAV) siRNA vectors that target two genes with opposing roles in TBI pathogenesis: the allegedly detrimental neuronal nitric oxide synthase (nNOS) and the potentially protective glutathione peroxidase 1 (GPx-1). In rat hippocampal progenitor cells, three siRNAs that target different regions of each gene (nNOS, GPx-1) effectively knocked down gene expression. However, in vivo, in our rat model of fluid percussion brain injury, the consequences of AAV-siRNA were variable. One nNOS siRNA vector significantly reduced the number of degenerating hippocampal neurons and showed a tendency to improve working memory. GPx-1 siRNA treatment did not alter TBI-induced neurodegeneration or working memory deficits. Nevertheless, microarray analysis of laser captured, virus-infected neurons showed that knockdown of nNOS or GPx-1 was specific and had broad effects on downstream genes. Since nNOS knockdown only modestly ameliorated TBI-induced working memory deficits, despite widespread genomic changes, manipulating expression levels of single genes may not be sufficient to alter functional outcome after TBI.