Project description: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:We inflicted TBI to chemokine-deficient mouse lines in order to establish involvement of various signalling pathways that may be addressed therapeutically. Interacting chemokine pathways in brain regulate distinct inflammatory cells. Activated microglia are separate from invading phagocytes and dendritic cells. Findings show potential targets to interfere with specific inflammatory responses after brain injury. TBI was carried out in Ccl3-/- and Ccr2-/- mice, total RNA prepared from injured cerebral neocortex after three days. RNA samples were from uninjured Ccl3-/- and Ccr2-/- mice as reference for hybridization on Affymetrix microarrays.
Project description:Genetic factors are believed to be of importance for outcome of traumatic brain injury (TBI). However, so far mainly allelic variation in apolipoprotein E4 has been studied in human TBI. In order to study the role of genetic factors in experimental TBI, we examined parental DA and PVG strains before and after TBI. A standardized weight drop injury was used and the pericontusional area was dissected 1 day after TBI and transcriptional profiling was performed.
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:We compared arginase-1+ macrophages (macrophages were defined by flow cytometry as CD45hi CD11b+ Ly6G-) with arginase-1- brain macrophages following traumatic brain injury (TBI) by isolating these cells from YARG transgenic mice, which express YFP under the arginase-1 promoter. Both cell populations were isolated from YARG brain tissues one day following TBI. We also examined the expression profile of peripheral blood monocytes (monocytes were defined by flow cytometry as CD11bhi F4/80+) from injured YARG mice and from normal YARG mice. Peripheral blood samples were compared to TBI brain macrophages to assess gene expression changes before and after infiltration into the brain. TBI macrophage subsets were identified by using a reporter mouse strain (YARG) that expresses eYFP from an IRES inserted at the 3' end of the gene for arginase-1 (Arg1), a hallmark of alternatively activated (M2) macrophages. One day after TBI, 21±1.5% of ipsilateral brain macrophages expressed relatively high levels of Arg1 as detected by YFP. Gene expression analysis of Arg1+ and Arg1- brain macrophage populations revealed that these populations were distinct from either classically activated (M1) macrophages or M2 macrophages, with features of both. The Arg1+ cells differed from Arg1- cells in multiple aspects, most notably in their chemokine repertoires. Thus, the macrophage response to TBI involves recruitment of at least two major macrophage subsets. Overall, our data indicate that the macrophage response to TBI is heterogeneous and unique. Four groups (Arg1- brain macrophages post-TBI, Arg1+ brain macrophages post-TBI, normal blood monocytes, blood monocytes post-TBI) were analyzed. Four replicates of each group were analyzed for a total of 16 samples (only 3 replicates of the blood monocyte groups are included in this submission).
Project description: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. Keywords: time-course
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