scholarly journals Transcriptomic Analysis of Mouse Brain After Traumatic Brain Injury Reveals That the Angiotensin Receptor Blocker Candesartan Acts Through Novel Pathways

2021 ◽  
Vol 15 ◽  
Author(s):  
Peter J. Attilio ◽  
Dustin M. Snapper ◽  
Milan Rusnak ◽  
Akira Isaac ◽  
Anthony R. Soltis ◽  
...  
Keyword(s):  
Gene Expression ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Brain Region ◽  
Molecular Mechanisms ◽  
Angiotensin Receptor Blockers ◽  
Differentially Expressed ◽  
Lesion Volume ◽  
Angiotensin Receptor ◽  
Post Injury

Traumatic brain injury (TBI) results in complex pathological reactions, where the initial lesion is followed by secondary inflammation and edema. Our laboratory and others have reported that angiotensin receptor blockers (ARBs) have efficacy in improving recovery from traumatic brain injury in mice. Treatment of mice with a subhypotensive dose of the ARB candesartan results in improved functional recovery, and reduced pathology (lesion volume, inflammation and gliosis). In order to gain a better understanding of the molecular mechanisms through which candesartan improves recovery after controlled cortical impact injury (CCI), we performed transcriptomic profiling on brain regions after injury and drug treatment. We examined RNA expression in the ipsilateral hippocampus, thalamus and hypothalamus at 3 or 29 days post injury (dpi) treated with either candesartan (0.1 mg/kg) or vehicle. RNA was isolated and analyzed by bulk mRNA-seq. Gene expression in injured and/or candesartan treated brain region was compared to that in sham vehicle treated mice in the same brain region to identify genes that were differentially expressed (DEGs) between groups. The most DEGs were expressed in the hippocampus at 3 dpi, and the number of DEGs reduced with distance and time from the lesion. Among pathways that were differentially expressed at 3 dpi after CCI, candesartan treatment altered genes involved in angiogenesis, interferon signaling, extracellular matrix regulation including integrins and chromosome maintenance and DNA replication. At 29 dpi, candesartan treatment reduced the expression of genes involved in the inflammatory response. Some changes in gene expression were confirmed in a separate cohort of animals by qPCR. Fewer DEGs were found in the thalamus, and only one in the hypothalamus at 3 dpi. Additionally, in the hippocampi of sham injured mice, 3 days of candesartan treatment led to the differential expression of 384 genes showing that candesartan in the absence of injury had a powerful impact on gene expression specifically in the hippocampus. Our results suggest that candesartan has broad actions in the brain after injury and affects different processes at acute and chronic times after injury. These data should assist in elucidating the beneficial effect of candesartan on recovery from TBI.

scholarly journals Chronic complement dysregulation drives neuroinflammation after traumatic brain injury: a transcriptomic study

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Amer Toutonji ◽  
Mamatha Mandava ◽  
Silvia Guglietta ◽  
Stephen Tomlinson
Keyword(s):  
Gene Expression ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Complement System ◽  
Classical Pathway ◽  
Post Injury ◽  
Complement Inhibition ◽  
Time Points ◽  
Complement Gene ◽  
The Complement System

AbstractActivation of the complement system propagates neuroinflammation and brain damage early and chronically after traumatic brain injury (TBI). The complement system is complex and comprises more than 50 components, many of which remain to be characterized in the normal and injured brain. Moreover, complement therapeutic studies have focused on a limited number of histopathological outcomes, which while informative, do not assess the effect of complement inhibition on neuroprotection and inflammation in a comprehensive manner. Using high throughput gene expression technology (NanoString), we simultaneously analyzed complement gene expression profiles with other neuroinflammatory pathway genes at different time points after TBI. We additionally assessed the effects of complement inhibition on neuropathological processes. Analyses of neuroinflammatory genes were performed at days 3, 7, and 28 post injury in male C57BL/6 mice following a controlled cortical impact injury. We also characterized the expression of 59 complement genes at similar time points, and also at 1- and 2-years post injury. Overall, TBI upregulated the expression of markers of astrogliosis, immune cell activation, and cellular stress, and downregulated the expression of neuronal and synaptic markers from day 3 through 28 post injury. Moreover, TBI upregulated gene expression across most complement activation and effector pathways, with an early emphasis on classical pathway genes and with continued upregulation of C2, C3 and C4 expression 2 years post injury. Treatment using the targeted complement inhibitor, CR2-Crry, significantly ameliorated TBI-induced transcriptomic changes at all time points. Nevertheless, some immune and synaptic genes remained dysregulated with CR2-Crry treatment, suggesting adjuvant anti-inflammatory and neurotropic therapy may confer additional neuroprotection. In addition to characterizing complement gene expression in the normal and aging brain, our results demonstrate broad and chronic dysregulation of the complement system after TBI, and strengthen the view that the complement system is an attractive target for TBI therapy.

scholarly journals A combination antioxidant therapy to inhibit NOX2 and activate Nrf2 decreases secondary brain damage and improves functional recovery after traumatic brain injury

2017 ◽  
Vol 38 (10) ◽  
pp. 1818-1827 ◽  
Author(s):  
Raghavendar Chandran ◽  
TaeHee Kim ◽  
Suresh L Mehta ◽  
Eshwar Udho ◽  
Vishal Chanana ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Motor Function ◽  
Neurological Dysfunction ◽  
Vehicle Group ◽  
Lesion Volume ◽  
Post Injury ◽  
Cortical Contusion ◽  
Nrf2 Activator

Uncontrolled oxidative stress contributes to the secondary neuronal death that promotes long-term neurological dysfunction following traumatic brain injury (TBI). Surprisingly, both NADPH oxidase 2 (NOX2) that increases and transcription factor Nrf2 that decreases reactive oxygen species (ROS) are induced after TBI. As the post-injury functional outcome depends on the balance of these opposing molecular pathways, we evaluated the effect of TBI on the motor and cognitive deficits and cortical contusion volume in NOX2 and Nrf2 knockout mice. Genetic deletion of NOX2 improved, while Nrf2 worsened the post-TBI motor function recovery and lesion volume indicating that decreasing ROS levels might be beneficial after TBI. Treatment with either apocynin (NOX2 inhibitor) or TBHQ (Nrf2 activator) alone significantly improved the motor function after TBI, but had no effect on the lesion volume, compared to vehicle control. Whereas, the combo therapy (apocynin + TBHQ) given at either 5 min/24 h or 2 h/24 h improved motor and cognitive function and decreased cortical contusion volume compared to vehicle group. Thus, both the generation and disposal of ROS are important modulators of oxidative stress, and a combo therapy that prevents ROS formation and potentiates ROS disposal concurrently is efficacious after TBI.

scholarly journals Administration of a 20-Hydroxyeicosatetraenoic Acid Synthesis Inhibitor Improves Outcome in a Rat Model of Pediatric Traumatic Brain Injury

2019 ◽  
Vol 41 (3-4) ◽  
pp. 166-176 ◽  
Author(s):  
Shiyu Shu ◽  
Zhi Zhang ◽  
Dawn Spicer ◽  
Ewa Kulikowicz ◽  
Ke Hu ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Ischemia Reperfusion ◽  
Memory Task ◽  
Male Rats ◽  
Lesion Volume ◽  
Hydroxyeicosatetraenoic Acid ◽  
Post Injury ◽  
Synthesis Inhibitor ◽  
Tnf Α

The arachidonic acid pathway metabolite 20-hydroxyeicosatetraenoic acid (20-HETE) contributes to ischemia/reperfusion brain injury. Inhibition of 20-HETE formation can protect the developing brain from global ischemia. Here, we examined whether treatment with the 20-HETE synthesis inhibitor N-hydroxy-N-4-butyl-2-methylphenylformamidine (HET0016) can protect the immature brain from traumatic brain injury (TBI). Male rats at postnatal day 9–10 underwent controlled cortical impact followed by intraperitoneal injection with vehicle or HET0016 (1 mg/kg, 5 min and 3 h post-injury). HET0016 decreased the lesion volume by over 50% at 3 days of recovery, and this effect persisted at 30 days as the brain matured. HET0016 decreased peri-lesion gene expression of proinflammatory cytokines (tumor necrosis factor-α [TNF-α], interleukin-1β [IL-1β]) at 1 day and increased reparative cytokine (IL-4, IL-10) expression at 3 days. It also partially preserved microglial ramified processes, consistent with less activation. HET0016 decreased contralateral hindlimb foot faults and improved outcome on the novel object recognition memory task 30 days after TBI. In cultured BV2 microglia, HET0016 attenuated the lipopolysaccharide-evoked increase in release of TNF-α. Our data show that HET0016 improves acute and long-term histologic and functional outcomes, in association with an attenuated neuroinflammatory response after contusion of an immature rat brain.

scholarly journals Zinc and Traumatic Brain Injury: From Chelation to Supplementation

2020 ◽  
Vol 8 (3) ◽  
pp. 36 ◽  
Author(s):  
Cathy W. Levenson
Keyword(s):  
Gene Expression ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Incidence Rate ◽  
Molecular Mechanisms ◽  
Behavioral Deficits ◽  
Zinc Accumulation ◽  
Regulated Gene Expression

With a worldwide incidence rate of almost 70 million annually, traumatic brain injury (TBI) is a frequent cause of both disability and death. Our modern understanding of the zinc-regulated neurochemical, cellular, and molecular mechanisms associated with TBI is the result of a continuum of research spanning more than three decades. This review describes the evolution of the field beginning with the initial landmark work on the toxicity of excess neuronal zinc accumulation after injury. It further shows how the field has expanded and shifted to include examination of the cellular pools of zinc after TBI, identification of the role of zinc in TBI-regulated gene expression and neurogenesis, and the use of zinc to prevent cognitive and behavioral deficits associated with brain injury.

scholarly journals N-arachidonoyl-L-serine (AraS) Possesses Proneurogenic Properties in Vitro and in Vivo after Traumatic Brain Injury

2013 ◽  
Vol 33 (8) ◽  
pp. 1242-1250 ◽  
Author(s):  
Ayelet Cohen-Yeshurun ◽  
Dafna Willner ◽  
Victoria Trembovler ◽  
Alexander Alexandrovich ◽  
Raphael Mechoulam ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Cannabinoid Receptor ◽  
Fold Increase ◽  
Lesion Volume ◽  
Post Injury ◽  
Neuroprotective Effects ◽  
Neurobehavioral Function

N-arachidonoyl-L-serine (AraS) is a novel neuroprotective endocannabinoid. We aimed to test the effects of exogenous AraS on neurogenesis after traumatic brain injury (TBI). The effects of AraS on neural progenitor cells (NPC) proliferation, survival, and differentiation were examined in vitro. Next, mice underwent TBI and were treated with AraS or vehicle. Lesion volumes and clinical outcome were evaluated and the effects on neurogenesis were tested using immunohistochemistry. Treatment with AraS led to a dose-dependent increase in neurosphere size without affecting cell survival. These effects were partially reversed by CB1, CB2, or TRPV1 antagonists. AraS significantly reduced the differentiation of NPC in vitro to astrocytes or neurons and led to a 2.5-fold increase in expression of the NPC marker nestin. Similar effects were observed in vivo in mice treated with AraS 7 days after TBI. These effects were accompanied by a reduction in lesion volume and an improvement in neurobehavioral function compared with controls. AraS increases proliferation of NPCs in vitro in cannabinoid-receptor-mediated mechanisms and maintains NPC in an undifferentiated state in vitro and in vivo. Moreover, although given at 7 days post injury, these effects are associated with significant neuroprotective effects leading to an improvement in neurobehavioral functions.

scholarly journals Early onset senescence and cognitive impairment in a murine model of repeated mTBI

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Nicole Schwab ◽  
YoungJun Ju ◽  
Lili-Naz Hazrati
Keyword(s):  
Gene Expression ◽  
Traumatic Brain Injury ◽  
Dna Damage ◽  
Cognitive Impairment ◽  
Brain Injury ◽  
Mild Traumatic Brain Injury ◽  
Cellular Senescence ◽  
Early Gene ◽  
Dna Breaks ◽  
Post Injury

AbstractMild traumatic brain injury (mTBI) results in broad neurological symptoms and an increased risk of being diagnosed with a neurodegenerative disease later in life. While the immediate oxidative stress response and post-mortem pathology of the injured brain has been well studied, it remains unclear how early pathogenic changes may drive persistent symptoms and confer susceptibility to neurodegeneration. In this study we have used a mouse model of repeated mTBI (rmTBI) to identify early gene expression changes at 24 h or 7 days post-injury (7 dpi). At 24 h post-injury, gene expression of rmTBI mice shows activation of the DNA damage response (DDR) towards double strand DNA breaks, altered calcium and cell–cell signalling, and inhibition of cell death pathways. By 7 dpi, rmTBI mice had a gene expression signature consistent with induction of cellular senescence, activation of neurodegenerative processes, and inhibition of the DDR. At both timepoints gliosis, microgliosis, and axonal damage were evident in the absence of any gross lesion, and by 7 dpi rmTBI also mice had elevated levels of IL1β, p21, 53BP1, DNA2, and p53, supportive of DNA damage-induced cellular senescence. These gene expression changes reflect establishment of processes usually linked to brain aging and suggests that cellular senescence occurs early and most likely prior to the accumulation of toxic proteins. These molecular changes were accompanied by spatial learning and memory deficits in the Morris water maze. To conclude, we have identified DNA damage-induced cellular senescence as a repercussion of repeated mild traumatic brain injury which correlates with cognitive impairment. Pathways involved in senescence may represent viable treatment targets of post-concussive syndrome. Senescence has been proposed to promote neurodegeneration and appears as an effective target to prevent long-term complications of mTBI, such as chronic traumatic encephalopathy and other related neurodegenerative pathologies.

scholarly journals What Do Machines Tell us About Dementia? Machine Learning Applied to Aging, Dementia and Traumatic Brain Injury Study

2021 ◽  
Author(s):  
Denis Arthur Pinheiro Moura ◽  
Joao Ricardo Mendes de Oliveira
Keyword(s):  
Gene Expression ◽  
Machine Learning ◽  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Expression Profiles ◽  
Brain Regions ◽  
Machine Learning Algorithms ◽  
Differentially Expressed ◽  
Classification Model ◽  
Specific Gene

Abstract Dementia, a syndrome characterized by the progressive deterioration of memory and cognition, arises from different pathologies, with Alzheimer's Disease (AD) its most common cause. Patterns of gene expression during dementia of different etiologies may function as generalist biomarkers of the condition. We used RNA-Seq data from the Allen Dementia and Traumatic Brain Injury Study (ADTBI) to identify differentially expressed genes in brains with dementia. Machine Learning algorithms Decision Trees (DT) and Random Forest (RF) were used to create models to identify dementia samples based on their gene expression profile. Importance analyses were conducted to identify the most relevant genes in each classification model. A total of 1629 differentially expressed (DE) genes were found in brains with the condition. Gene PAN3-AS1 was the only DE gene across more than three brain regions. The artificial intelligence models were capable of identifying correctly up to 92.85% of dementia samples. Our analyses provide interesting insights regarding using brain-specific gene expression profiles as biomarkers of dementia, identifying genes possibly involved with dementia, and guiding future studies in prediction and early identification of the syndrome.

scholarly journals The CNS lymphatic system modulates the adaptive neuro-immune response in the perilesional cortex in a mouse model of traumatic brain injury

2019 ◽  
Author(s):  
Wojciechowski Sara ◽  
Vihma Maria ◽  
Galbardi Barbara ◽  
Virenque Anaïs ◽  
Meike H. Keuters ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Immune Response ◽  
T Cells ◽  
Brain Injury ◽  
Lymphatic Vessels ◽  
Lesion Size ◽  
Lesion Volume ◽  
Post Injury ◽  
Circulating T Cells ◽  
The Brain

AbstractRationaleThe recently discovered meningeal lymphatic vessels (mLVs) have been proposed to be the missing link between the immune and the central nervous systems. The role of mLVs in modulating the neuro-immune response following a brain injury, however, has not been analyzed. Parenchymal T lymphocyte infiltration has been previously reported as part of secondary events after traumatic brain injury (TBI), suggestive of an adaptive neuro-immune response. The phenotype of these cells has remained mostly uncharacterized. In this study, we identified the subpopulations of T cells infiltrating the perilesional areas 30 days post-injury (an early-chronic time point). Furthermore, we analyzed how the lack of mLVs affects the magnitude and the type of immune response in the brain after TBI.MethodsTBI was induced in K14-VEGFR3-Ig transgenic (TG) mice or in their littermate controls (WT; wild type), applying a controlled cortical impact (CCI). One month after TBI, T cells were isolated from cortical areas ipsilateral or contralateral to the trauma and from the spleen, then characterized by flow cytometry. Lesion size in each animal was evaluated by MRI.ResultsIn both WT and TG-CCI mice, we found a prominent T cell infiltration in the brain confined to the perilesional cortex and hippocampus. The majority of infiltrating T cells were cytotoxic CD8+ expressing a CD44hiCD69+ phenotype, suggesting that these are effector resident memory T cells. K14-VEGFR3-Ig mice showed a significant reduction of infiltrating CD4+ T lymphocytes, implying that mLVs are important in establishing a proper neuro-immune response. Extension of the lesion (measured as lesion volume from MRI) did not differ between the genotypes. Finally, TBI did not relate with alterations in peripheral circulating T cells, as assessed one month after injury induction.ConclusionsOur data support the hypothesis that mLVs are pivotal for a proper and specific neuro-immune response after TBI, which is principally mediated by the resident memory CD8+ T cells.

scholarly journals Intranasal insulin treatment of an experimental model of moderate traumatic brain injury

2017 ◽  
Vol 37 (9) ◽  
pp. 3203-3218 ◽  
Author(s):  
Fiona Brabazon ◽  
Colin M Wilson ◽  
Shalini Jaiswal ◽  
John Reed ◽  
William H Frey ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Glucose Uptake ◽  
Male Rats ◽  
Lesion Volume ◽  
Intranasal Insulin ◽  
Post Injury ◽  
Fdg Uptake ◽  
Moderate Traumatic Brain Injury ◽  
18F Fdg

Traumatic brain injury (TBI) results in learning and memory dysfunction. Cognitive deficits result from cellular and metabolic dysfunction after injury, including decreased cerebral glucose uptake and inflammation. This study assessed the ability of intranasal insulin to increase cerebral glucose uptake after injury, reduce lesion volume, improve memory and learning function and reduce inflammation. Adult male rats received a controlled cortical impact (CCI) injury followed by intranasal insulin or saline treatment daily for 14 days. PET imaging of [18F]-FDG uptake was performed at baseline and at 48 h and 10 days post-injury and MRI on days three and nine post injury. Motor function was tested with the beam walking test. Memory function was assessed with Morris water maze. Intranasal insulin after CCI significantly improved several outcomes compared to saline. Insulin-treated animals performed better on beam walk and demonstrated significantly improved memory. A significant increase in [18F]-FDG uptake was observed in the hippocampus. Intranasal insulin also resulted in a significant decrease in hippocampus lesion volume and significantly less microglial immunolabeling in the hippocampus. These data show that intranasal insulin improves memory, increases cerebral glucose uptake and decreases neuroinflammation and hippocampal lesion volume, and may therefore be a viable therapy for TBI.

scholarly journals Constitutive gene expression differs in three brain regions important for cognition in neophobic and non-neophobic house sparrows (Passer domesticus)

2021 ◽  
Author(s):  
Christine R Lattin ◽  
Tosha R Kelly ◽  
Kevin M Johnson ◽  
Morgan W Kelly
Keyword(s):  
Gene Expression ◽  
Executive Function ◽  
Brain Region ◽  
Serotonin Receptor ◽  
Molecular Mechanisms ◽  
Passer Domesticus ◽  
Brain Regions ◽  
Differentially Expressed ◽  
Neural Function ◽  
House Sparrows

Neophobia (aversion to new objects, food, and environments) is a personality trait that affects the ability of wildlife to adapt to new challenges and opportunities. Despite the ubiquity and importance of this trait, the molecular mechanisms underlying repeatable individual differences in neophobia in wild animals are poorly understood. We evaluated wild-caught house sparrows (Passer domesticus) for neophobia in the lab using novel object tests. We then selected the most and least neophobic individuals (n=3 of each) and extracted RNA from four brain regions involved in learning, memory, threat perception, and executive function: striatum, dorsomedial hippocampus, medial ventral arcopallium, and caudolateral nidopallium (NCL). Our analysis of differentially expressed genes (DEGs) used 11,889 gene regions annotated in the house sparrow reference genome for which we had an average of 25.7 million mapped reads/sample. PERMANOVA identified significant effects of brain region, phenotype (neophobic vs. non-neophobic), and a brain region by phenotype interaction. Comparing neophobic and non-neophobic birds revealed constitutive differences in DEGs in three of the four brain regions examined: hippocampus (12% of the transcriptome significantly differentially expressed), striatum (4%) and NCL (3%). DEGs included important known neuroendocrine mediators of learning, memory, executive function, and anxiety behavior, including serotonin receptor 5A, dopamine receptors 1, 2 and 5 (downregulated in neophobic birds), and estrogen receptor beta (upregulated in neophobic birds). These results suggest that some of the behavioral differences between phenotypes may be due to underlying gene expression differences in the brain. The large number of DEGs in neophobic and non-neophobic birds also implies that there are major differences in neural function between the two phenotypes that could affect a wide variety of behavioral traits beyond neophobia.

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