A Single Primary Blast-Induced Traumatic Brain Injury in a Rodent Model Causes Cell-Type Dependent Increase in Nicotinamide Adenine Dinucleotide Phosphate Oxidase Isoforms in Vulnerable Brain Regions

Abstract

Blast-induced traumatic brain injury (bTBI) is a leading cause of morbidity in soldiers on the battlefield and in training sites with long-term neurological and psychological pathologies. Previous studies from our laboratory demonstrated activation of oxidative stress pathways after blast injury, but their distribution among different brain regions and their impact on the pathogenesis of bTBI have not been explored. The present study examined the protein expression of two isoforms: nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 1 and 2 (NOX1, NOX2), corresponding superoxide production, a downstream event of NOX activation, and the extent of lipid peroxidation adducts of 4-hydroxynonenal (4HNE) to a range of proteins. Brain injury was evaluated 4 h after the shock-wave exposure, and immunofluorescence signal quantification was performed in different brain regions. Expression of NOX isoforms displayed a differential increase in various brain regions: in hippocampus and thalamus, there was the highest increase of NOX1, whereas in the frontal cortex, there was the highest increase of NOX2 expression. Cell-specific analysis of changes in NOX expression with respect to corresponding controls revealed that blast resulted in a higher increase of NOX1 and NOX 2 levels in neurons compared with astrocytes and microglia. Blast exposure also resulted in increased superoxide levels in different brain regions, and such changes were reflected in 4HNE protein adduct formation. Collectively, this study demonstrates that primary blast TBI induces upregulation of NADPH oxidase isoforms in different regions of the brain parenchyma and that neurons appear to be at higher risk for oxidative damage compared with other neural cells.

Glial Activation in the Thalamus Contributes to Vestibulomotor Deficits Following Blast-Induced Neurotrauma

“…Glial responses have been identified at the acute phase of injury following bTBI, however there is still limited knowledge on the sub-acute and early chronic outcomes, and how they contribute to vestibulomotor and behavioral deficits. Previous studies report on acute changes (2–72 h) of glial dysfunction (elevated levels of reactive astrocytes and activated microglia) in brain regions such as the hippocampus, amygdala, and the pre-frontal cortex ( 57 , 60 , 65 ). Sub-acute (3–14 days) results have also provided insight regarding the dynamic glial response occurring in the brain following blast injury ( 45 , 66 ).…”

Matrix Inversion and Subset Selection (MISS): A novel pipeline for mapping of diverse cell types across the murine brain

“…The spatially varying abundances of cell types considered selectively vulnerable to tau or ɑ-synuclein inclusions can be mapped using MISS, and their correspondence with the spatial pattern of protein pathologies can be tested; for instance, recent experiments suggest cell type selectivity of tau pathology (Fu et al, 2018(Fu et al, , 2019Muratore et al, 2017). Cellular vulnerability in other neurological conditions can also be interrogated using MISS, including psychiatric diseases such as schizophrenia (Skene et al, 2018), and traumatic brain injury, which was hypothesized to preferentially involve certain types of cells in both injury and recovery phases (Arneson et al, 2018;Rama Rao et al, 2018).…”

“…While regional gene expression profiles did not seem especially predictive in a prior analysis 44 , other experiments suggest cell type selectivity of tau pathology [45][46][47] . Cellular vulnerability in other neurological conditions can also be interrogated using MISS, including psychiatric diseases such as schizophrenia 48 , and traumatic brain injury (TBI), which was hypothesized to preferentially involve certain types of cells in both injury and recovery phases 49,50 . These applications exemplify the broad scientific utility of whole-brain cell type quantification.…”

“…Characterizing whole-brain distributions of neural cell types is a topic of keen interest in modern neuroanatomy, with many applications to both basic and clinical neuroscience research (Arneson et al, 2018;Fu et al, 2018Fu et al, , 2019Muratore et al, 2017;Rama Rao et al, 2018;Skene et al, 2018). Advances in molecular methods for quantifying gene expression and data analytic cell clustering techniques based on morphologic or genetic profiles are enabling the mapping of meso-and microscale neuronal and nonneuronal cell type architecture at a whole-brain level (Codeluppi et al, 2018;Erö et al, 2018;Kim et al, 2017;Moffitt et al, 2018;Murakami et al, 2018;Tasic et al, 2018;Wang et al, 2018;Zeisel et al, 2018).…”

Investigation of the direct and indirect mechanisms of primary blast insult to the brain

“…We conducted immunohistochemical analyses on the coronal brain slices to assess the expressions of glial fibrillary acidic protein (GFAP), ionized calcium-binding adapter molecule 1 protein (Iba-1), and neuron-specific nuclear protein (NeuN) after blast exposure. The expressions of GFAP, Iba-1, and NeuN are associated with the distributions of astrocytes, microglia, and neuronal cells, respectively 21 .…”