Transcription profiling of rat brain time series samples treated with lateral fluid percussion injury or sham surgery without injury to investigate the physiological effects of taumatic brain injury
ABSTRACT: Traumatic brain injury (TBI) induces a complex cascade of molecular and physiological effects. This study proposes to investigate the gene expression profile in cortex and hippocampus over early time points, following two different injury severities. These results will complement prior knowledge of both metabolic and neuroplastic changes after TBI, as well as serve as a starting point to investigate additional gene families whose expression is altered after TBI.,To characterize the profile of gene expression following a diffuse traumatic brain injury of varying severity in adult rats. ,Distinct patterns of gene expression following traumatic brain injury will occur in a time- and injury-dependent fashion. In particular, changes in expression of enzymes involved in energy metabolism and neuroplasticity will be detected.,Adult rats will be subjected to mild and severe lateral fluid percussion injury OR sham surgery without injury. At various post-injury timepoints (0.5, 4 and 24 hours), animals will be sacrificed, brain regions (parietal cortex and hippocampus, ipsilateral and contralateral to injury) will be dissected and RNA isolated. RNA will be used to synthesize cRNA probes for microarray hybridization. RNA from 2 matched animals will be pooled onto a single chip (U34A rat, Affymetrix). Comparisons will be made between sham and injured animals, with brain region, injury severity, and post-injury time point as the experimental variables.
Project description:Traumatic brain injury (TBI) alters and dysregulates the expression of thousands of genes in the brain. Since some of the most common problems in TBI patients are learning and memory deficits, we are studying the effects of TBI on the hippocampus, a region of the brain which is essential for learning and memory and which is known to be particularly vulnerable to TBI. We are interested in understanding how potential neuroprotective drugs alter the TBI-induced gene expression profile. The objective of this study is to elucidate and compare the differential gene expression profiles in the hippocampus of naive, sham-control, TBI and TBI plus drug treated rats. JM6, PMI-006 and E33 are three compounds with neuroprotective, anti-inflammatory and anti-oxidative effects. Our goal is to determine if different neuroprotective compounds have similar effects on common gene targets. These genes and the cell signaling pathways linked to them would then be the target of new therapeutic strategies for TBI. Rats were prepared for fluid percussion traumatic brain injury or sham injury (naïve rats had no anesthesia and were not handled in any way and gene expression in their brains serve as baseline data) and 24 hr post-injury, hippocampi were obtained, and stored in RNA later. Total RNA was isolated, quantitified and used for Agilent microarray analysis at GenUs Biosystems. Each group of naive, sham control, TBI and TBI plus JM6, TBI plus PMI-006 and TBI plus E33 (estrogen) has three biological replicates.
Project description:Traumatic brain injury dysregulates microRNA expression in the brain. We hypothesized that injury-induced epigenetic changes contribute to neurodegeneration and learning and memory deficits after TBI. These changes may provide a mechanistic explanation for neuropsychiatric comorbidities in TBI patients. Our objective is to compare and contrast the effects of several neuroprotective drugs (JM6, PMI-006 and E33-estrogen) on the TBI-induced changes in microRNA expression in the hippocampus, a region of the brain that is critical for learning and memory. We will also study if different neuroprotective drugs have similar effects on common microRNAs which may cooperatively regulate a common set of gene targets. 3 biological samples each of Naïve, Sham control, TBI and TBI plus JM6, TI plus PMI-006, and TBI plus E33 rat hippocampi were obtained 24 hr post-sham injury or TBI, stored in RNA later and sent to GenUs Biosystems for microRNA microarray analysis.
Project description:Blast traumatic brain injury (B-TBI) affects military and civilian personnel. Presently there are no approved drugs for blast brain injury. Exendin-4, administered subcutaneously, was evaluated as a pre-treatment (48 hours) and post-injury treatment (2 hours) on neurodegeneration, behaviors and gene expressions in a murine open field model of blast injury. B-TBI induced neurodegeneration, changes in cognition and genes expressions linked to dementia disorders. Exendin-4, administered pre- or post-injury ameliorated B-TBI-induced neurodegeneration at 72 hours, memory deficits from days 7-14 and attenuated genes regulated by blast at day 14 post-injury. The present data suggest shared pathological processes between concussive and B-TBI, with endpoints amenable to beneficial therapeutic manipulation by exendin-4. B-TBI-induced dementia-related gene pathways and cognitive deficits in mice somewhat parallel epidemiological studies of Barnes and co-workers who identified a greater risk in US military veterans who experienced diverse TBIs, for dementia in later life. Overall design: Experimental conditions used to create a blast traumatic brain injury (B-TBI) and the subsequent model characterization have been described in detail previously. In short, male ICR mice (30-40 g) were anaesthetized with a combination of ketamine (100 mg/kg) and xylazine (10 mg/kg). Once fully anaesthetized, the animals were positioned ‘side-on’ to the blast overpressure on an elevated platform in a circle, 7 meters from the source of the detonation generated by the detonation of 500 g of trinitrotoluene (TNT). The maximum overpressure generated by the detonation was 2.5 PSI (17.23 kPa). The following animal treatment groups were utilized: sham operated no blast (Sham); blast traumatic brain injury (B-TBI); Ex-4 as a pre-treatment to the blast injury (Ex-4/B-TBI); Ex-4 as a post-treatment to the blast injury (B-TBI/Ex-4) and Ex-4 but no injury (Ex-4). Hippocampal brain gene expression was examined on day 3 and day 14 (Experiment GSE44625) after the blast traumatic brain injury (B-TBI) or sham procedure. Animals received 3.5 pM/kg/min (21ug/kg/day) Exendin-4 using Alzet micro-osmotic pumps either as a pre-treatment to the blast injury 48 hours before (Ex-4 pre-TBI) or as a post-treatment 2 hours after the blast injury (Ex-4 post-TBI). Animals in a previous data set on Day 14 (GSE44625) were administered Ex-4 as a pre-treatment.
Project description:TBI was induced with lateral fluid-percussion injury in adult male rats. MBD-seq of the perilesional cortex, ipsilateral thalamus and ipsilateral hippocampus was performed at 3 months post-TBI. The data was used to identify differential methylation of gene promoter, gene body, and exons in the perilesional cortex , thalamus and hippocampus. Overall design: TBI was induced to 5 rats, 5 sham operated served as a controls.
Project description:Time dependent-profiles in the gene expression level following lateral moderate fluid percussion injury in the rat brain We used microarray to elucidate relationship between the alteration of gene expression levels and the progression of brain damages following traumatic brain injury. To examine the levels of gene expression in the early phase of traumatic brain injury, we analyzed the gene expression at 3, 6, 12, and 48 h after trauma using the lateral moderate fluid percussion TBI model. The ratios of the gene expression level were compared between chips corresponding to the 3, 6 and 12 h fluid percussion groups and the sham group chips. On the other hand, the rations of gene expression level after 48 h FPI were compared with 48 h sham chip, because the gene expression levels of 48 h sham chip were distinct from sham group chips (3, 6 and 12 h) in the cluster and principal components analyses.
Project description:Time dependent-profiles in the gene expression level following lateral moderate fluid percussion injury in the rat brain We used microarray to elucidate relationship between the alteration of gene expression levels and the progression of brain damages following traumatic brain injury. Overall design: To examine the levels of gene expression in the early phase of traumatic brain injury, we analyzed the gene expression at 3, 6, 12, and 48 h after trauma using the lateral moderate fluid percussion TBI model. The ratios of the gene expression level were compared between chips corresponding to the 3, 6 and 12 h fluid percussion groups and the sham group chips. On the other hand, the rations of gene expression level after 48 h FPI were compared with 48 h sham chip, because the gene expression levels of 48 h sham chip were distinct from sham group chips (3, 6 and 12 h) in the cluster and principal components analyses.
Project description:To address the hypothesis that silencing deleterious or protective injury-induced genes in the rat hippocampus will reduce or increase the numbers of injured hippocampal neurons, alter cellular pathways essential for neuronal function and improve or worsen functional outcome after traumatic brain injury (TBI), we evaluated the effects of silencing neuronal nitric oxide synthase (nNOS) and glutathione peroxidase-1 (GPx-1) expression in the injured rat hippocampus. Overall design: Two weeks post-TBI/post-AAV treatment, hippocampal pyramidal neurons were laser captured for comparative whole genome microarray analysis.
Project description:We report the altered expression profiles of lncRNA and mRNA in mice cortex afetr traumatic brain injury (TBI).Total of 27,457 transcripts were identified as mRNA and 37,073 transcripts were identified as lncRNA. Total of 823 lncRNAs and 1,580 mRNAs were significantly changed after TBI according to the criteria: |log2(fold change)|>1, P<0.05. In addition, total of 360 new mRNAs and 8,041 new lncRNAs were identified in current sequencing study. Overall design: TBI was induced in C57BL/6 mice. The LncRNA and mRNA expression profiles in cortex of normal mice and TBI mice were examined by RNA-Seq.
Project description:Warfare has long been associated with traumatic brain injury (TBI) in militarized zones. Common forms of TBI can be caused by a physical insult to the head-brain or by the effects of a high velocity blast shock wave generated by the detonation of an explosive device. While both forms of trauma are distinctly different regarding the mechanism of trauma induction, there are striking similarities in the cognitive and emotional status of survivors. Presently, proven effective therapeutics for the treatment of either form of TBI are unavailable. To be able to develop efficacious therapies, studies involving animal models of physical- and blast-TBI are required to identify possible novel or existing medicines that may be of value in the management of clinical events. We examined indices of cognition and anxiety-like behavior and the hippocampal gene transcriptome of mice subjected to both forms of TBI. We identified common behavioral deficits and gene expression regulations, in addition to unique injury-specific forms of gene regulation. Molecular pathways presented a pattern similar to that seen in gene expression. Interestingly, pathways connected to Alzheimer’s disease displayed a markedly different form of regulation depending on the type of TBI. While these data highlight similarities in behavioral outcomes after trauma, the divergence in hippocampal transcriptome observed between models suggests that, at the molecular level, the TBIs are quite different. These models may provide tools to help define therapeutic approaches for the treatment of physical- and blast-TBIs. Based upon observations of increasing numbers of personnel displaying TBI related emotional and behavioral changes in militarized zones, the development of efficacious therapies will become a national if not a global priority. Keywords: Physical-traumatic brain injury; Blast-traumatic brain injury; Cognitive dysfunction; Gene expression; Molecular pathway(s); Neurodegeneration; Stem cells; Alzheimer’s disease A mild physical-TBI was induced using a concussive head trauma device described previously (Milman et al., 2005; Zohar et al., 2003). Briefly, mice were lightly anesthetized (Isoflurane) and placed under the weight-drop concussive head trauma instrument. The device consisted of a metal tube (inner diameter 13 mm), placed vertically over the mouse head. A metal weight (30 g) was dropped from the top of the tube (80 cm) and struck the skull at the right side temporal area between the corner of the eye and the ear. A sponge supported the head, allowing some antero-posterior motion without any rotational head movement at the moment of the impact. Experimental conditions used to create a mild low-level blast-TBI and the subsequent model characterization, have been described in detail elsewhere (Rubovitch et al., 2011). In brief, mice were anaesthetized with a combination of ketamine (100 mg/kg) and xylazine (10 mg/kg). Once the animals were fully anaesthetized they were placed at a defined distance from a detonation source, in this case 7 meters. Pressure sensors were used to measure the explosion shock wave pressure (PSI) generated by the detonation (Free-Field ICP® Blast Pressure Sensor; PCB Piezoelectronics, Depew, NY, USA, Model 137). At 7 meters from the source of the detonation, the animals were exposed to a maximum of a 2.5 PSI (17.2 kPa) pressure shock wave. Immediately after the induction of the injury, mice were placed back in their cages. Once the animals had recovered from the anesthesia, basic neurological assessments were undertaken to identify any acute neurological dysfunction. Only animals exhibiting no evidence of acute neurological damage post injury were subsequently used in further experiments. Sham treated mouse groups were treated identically; however, they were not exposed to physical- or blast-TBI. Mouse hippocampus tissues were randomly selected from the larger library of samples generated from the behavioral experiments and the numbers utilized in the gene expression study were as follows: sham, n = 5: physical-TBI, n = 4; blast-TBI, n = 7.
Project description:TBI was induced with lateral fluid-percussion injury in adult male rats. Genome-wide RNA-seq of the perilesional cortex, ipsilateral thalamus and dorsal hippocampus was performed at 3 months post-TBI. The data highlighted chronic transcriptional changes, particularly, in the perilesional cortex and thalamus. Genes showing a significantly altered expression both in the cortex and thalamus were submitted to the LINCS web query to identify novel pharmacotherapies to improve post-TBI outcome. Overall design: TBI was induced to 5 rats, 5 sham operated served as a controls.