Transcription profiling time series of Rattus norvegicus raphe magnus and sensorimotor cortex samples following moderate spinal cord injury
ABSTRACT: Summary: Spinal cord injury (SCI) is a damage to the spinal cord induced by trauma or disease resulting in a loss of mobility or feeling. SCI is characterized by a primary mechanical injury followed by a secondary injury in which several molecular events are altered in the spinal cord often resulting in loss of neuronal function. Analysis of the areas directly (spinal cord) and indirectly (raphe and sensorimotor cortex) affected by injury will help understanding mechanisms of SCI. Hypothesis: Areas of the brain primarily affected by spinal cord injury are the Raphe and the Sensorimotor cortex thus gene expression profiling these two areas might contribute understanding the mechanisms of spinal cord injury. Specific Aim: The project aims at finding significantly altered genes in the Raphe and Sensorimotor cortex following an induced moderate spinal cord injury in T9.
Project description:Spinal cord injury (SCI) is a devastating condition resulting in permanent and irreversible deficits. Despite regeneration attempts, the neurons fail due to several dysfunctions. A number of studies have already revealed that, following SCI, microRNAs show two opposite kinds of alterations, one detrimental and one protective. However, there is still little evidence of specific microRNAs involved in axon regrowth. The aim of this project is the characterization of microRNA expression changes in sensorimotor cortex and corticospinal motor neurons, whose axons are severed by SCI. Overall design: miRNA profiling in SCI mouse model (P90) at a specific time point (7 days). Complete transection of the spinal cord was induced at the C5-C6 level in adult mice (3 WT vs. 3 SCI per each group). At 7 days post injury, the sensorimotor cortex was dissected, collected for RNA extraction and the HD sRNA library was sequenced.
Project description:Spinal cord injury (SCI) is a devastating condition resulting in permanent and irreversible deficits. Despite regeneration attempts, the neurons fail due to several dysfunctions. A number of studies have already revealed that, following SCI, microRNAs show two opposite kinds of alterations, one detrimental and one protective. However, there is still little evidence of specific microRNAs involved in axon regrowth. The aim of this project is the characterization of microRNA expression changes in sensorimotor cortex and corticospinal motor neurons, whose axons are severed by SCI. Overall design: miRNA profiling in SCI mouse model (P15 and P90) at different time points (12h and 3 days). Complete transection of the spinal cord was induced at the C5-C6 level in postnatal day 15 C57BL/6J male mice at 12h and 3 days after injury (3 WT vs. 3 SCI) and in adult mice at 12h and 3 days post injury (3 WT vs. 3 SCI per each group). The sensorimotor cortex was dissected, collected for RNA extraction and the HD sRNA library was sequenced.
Project description:Sensorimotor dysfunction following incomplete spinal cord injury (SCI) is often characterized by paralysis, spasticity and pain. Previously, we showed that intrathecal (i.t.) administration of the albumin-oleic acid (A-OA) complex in rats with SCI produced partial improvement of these symptoms and that oral 2-hydroxyoleic acid (HOA), a non-hydrolyzable OA analogue), was efficacious in the modulation and treatment of nociception and pain-related anxiety, respectively. Here we observed that intrathecal treatment with the complex albumin-HOA (A-HOA) every 3 days following T9 spinal contusion injury promoted significant recovery in locomotor function and marked an inhibition of TA noxious reflex activity (i.e., nociception) in Wistar rats. To investigate the mechanism of action of A-HOA, microarray analysis was carried out in the spinal cord lesion area. Representative genes involved in pain and neuroregeneration were selected to validate the changes observed in the microarray analysis by quantitative real-time RT-PCR. Comparison of the expression between healthy rats, SCI rats, and SCI treated with A-HOA rats revealed relevant changes in the expression of genes associated with neuronal morphogenesis and growth, neuronal survival, pain and inflammation. Thus, treatment with A-HOA not only induced a significant overexpression of growth and differentiation factor 10 (GDF10), tenascin C (TNC), aspirin (ASPN) and sushi-repeat-containing X-linked 2 (SRPX2), but also a significant reduction in the expression of prostaglandin E synthase (PTGES) and phospholipases A1 and A2 (PLA1/2). Currently, SCI has very important unmet clinical needs. A-HOA proved to downregulate genes involved in inflammation and upregulate genes involved in neuron growth, which balanced the important body response to medular lesion and allowed recovery from paralysis and pain. Overall design: We use four different animals for each experimental group which were extracted and processed separately
Project description:Summary: Spinal cord injury (SCI) is a damage to the spinal cord induced by trauma or disease resulting in a loss of mobility or feeling. SCI is characterized by a primary mechanical injury followed by a secondary injury in which several molecular events are altered in the spinal cord often resulting in loss of neuronal function. Hypothesis: Spinal cord injury (SCI) induces a cascade of molecular events including the activation of genes associated with transcription factors, inflammation, oxidative stress, ionic imbalance, apoptosis and neuroregeneration which suggests the existance of endogenous reparative attempts. However, not all mechanisms following SCI are well known. Specific Aim: The goal of this project is to analyze the molecular events following spinal cord injury 1 cm above, below, and at the site of injury (T9), aiming at finding potential new targets to improve recovery and therapy.
Project description:Traumatic spinal cord injury (SCI) often leads to loss of locomotor function. Neuroplasticity of spinal circuitry underlies some functional recovery and therefore represents a therapeutic target to improve locomotor function following SCI. However, the cellular and molecular mechanisms mediating neuroplasticity below the lesion level are not fully understood. The present study performed a gene expression profiling in the rat lumbar spinal cord at 1 and 3 weeks after contusive SCI at T9. The below-level gene expression profiles were compared with those of animals that were subjected to treadmill locomotor training. Rat lumbar spinal cords were taken for the microarray analysis at 1 and 3 weeks after contusive spinal cord injury at the T9 level. Another group of rats received treadmill locomotor training for 3 weeks, and theirs spinal cords were harvested for the microarray. The changes in gene expression after spinal cord injury were analyzed at the two time points. The influence of treadmill locomotor training was evaluated by comparing gene expression profiles between animals with or without treadmill training.
Project description:The aneurysm clip impact-compression model of spinal cord injury (SCI) in animals mimics the primary mechanism of SCI in human, i.e. acute impact and persisting compression; and its histo-pathological and behavioural outcomes are extensively similar to the human SCI. In order to understand the distinct molecular events underlying this injury model, an analysis of global gene expression of the acute, subacute and chronic stages of a moderate to severe injury to the rat spinal cord was conducted using a microarray gene chip approach. Rat thoracic spinal cord (T7) was injured using aneurysm clip impact-compression injury model and the epicenter area of injured spinal cord was isolated for RNA extraction and processing and hybridization on Affymetrix GeneChip arrays.
Project description:Astrocytes, the most abundant cells in the central nervous system, promote synapse formation and help refine neural connectivity. Although they are allocated to spatially distinct regional domains during development, it is unknown whether region-restricted astrocytes are functionally heterogeneous. Here we show that postnatal spinal cord astrocytes express several region-specific genes, and that ventral astrocyte-encoded Semaphorin3a (Sema3a) is required for proper motor neuron and sensory neuron circuit organization. Loss of astrocyte-encoded Sema3a led to dysregulated α−motor neuron axon initial segment orientation, markedly abnormal synaptic inputs, and selective death of α−but not of adjacent γ−motor neurons. Additionally, a subset of TrkA+ sensory afferents projected to ectopic ventral positions. These findings demonstrate that stable maintenance of a positional cue by developing astrocytes influences multiple aspects of sensorimotor circuit formation. More generally, they suggest that regional astrocyte heterogeneity may help to coordinate postnatal neural circuit refinement. 12 total samples consisting of three biological replicates each of flow sorted postnatal day 7 dorsal spinal cord astrocytes, ventral spinal cord astrocytes, dorsal SC non astrocytes, and ventral SC non astrocytes
Project description:To determine whether the expression levels of circular RNAs were altered and lay a foundation for future work, we used high-throughput microarray analysis to screen circular RNAs expression patterns in the spinal cord of adult rats after traumatic spinal cord injury (SCI), finally to evaluate the potential rat models as a platform for the development of novel therapeutic targets for spinal cord injury in future clinical studies. Overall six rats at 3 days post-SCI in two groups were used to perform the microarray. Overall design: Six rats were randomly assigned to two groups: rats in the sham control group (n=3) were treated with laminectomy alone without contusion; rats in the SCI group (n=3) were subjected to laminectomy plus contusion. Rats were anesthetized at 3 days post-SCI, and a 1cm long segment of spinal cord, including the injury epicenter, was dissected and collected for the experiment.
Project description:Purpose: Spinal cord injury (SCI) is a devastating neurological disease without effective treatment. To generate a comprehensive view of the mechanisms involved in SCI pathology, we applied RNA-sequencing (RNA-seq) technology to characterize the temporal changes in global gene expression after contusive SCI in mice. Method Part1: A total of 27 female C57BI/6J mice (10-16 weeks of age; 20-25g; The Jackson Laboratory, Bar Harbor, ME) were used with 9 mice in each of following groups: shame control, 2 and 7 days after SCI. The surgical procedure for SCI were described previously [PMID:23289019]. Briefly, after anesthetization with a mixed solution of ketamine (80 mg/kg, ip) and xylazine (10 mg/kg, ip), mice received a dorsal laminectomy at the 9th thoracic vertebral (T9) level to expose the spinal cord and then a moderate T9 contusive injury using an Infinite Horizons impactor (PrecisionSystems and Instrumentation) at 60 kdyn with the spinestabilized using steel stabilizers inserted under the transverse processes one vertebra above and below the injury [PMID:19196178] . The shame control mice received only a dorsal laminectomy without contusive injury. Afterwards, the wound was sutured in layers, bacitracin ointment(Qualitest Pharmaceuticals,Huntsville, AL) was applied tothe wound area, 0.1mL of a 20 mg/ml stock of gentamicin(ButlerSchein, Dublin, OH) was injected subcutaneously, and the animals recovered on a water-circulating heating pad. Then mice received analgesic agent, buprenorphin(0.05 mg/kg, SQ; Reckitt Benckise, Hull, England)twice a day for two days. Bladders were manually expressed until automatic voiding returned spontaneously, which generally was within 7 days. At 2 or 7 days after SCI, the mice were anesthetized again with ketamine and xylazine and perfused briefly with normal physical saline. The injured spinal cords were then dissected and three 0.5 mm pieces of spinal cord were cut in the injured epicenter. All spinal cords were immediately frozen in liquid nitrogen and processed for RNA isolation. The spinal cords from three mice were combined into one biological replicate for RNA extraction. Three biological replicates were used. Method Part2: RNA-Seq was performed on the polyadenylated fraction of RNA isolated from tissue samples of acute (2D) and subacute phase (7D) and normal tissues (control, denoted as CTR hereafter). Three biological replicates were used for each phase.150-300 ng total RNAs were used for each sequencing library. RNA samples were polyA selected and paired-end sequencing libraries were constructed using TruSeq RNA Sample Prep Kit as described in the TruSeq RNA Sample Preparation V2 Guide (Illumina).The samples were then sequenced using the Illumina HiSeq sequencer. More than 30 million 100bp paired-end reads were generated from each biological replicate. Method Part3: Read mapping and Transcriptome construction were done by using optimized pipeline which integrate Tophat followed by Cufflinks. Result: We sequenced tissue samples from acute and subacute phases (2 days and 7 days after injury) and systematically characterized the transcriptomes with the goal of identifying pathways and genes critical in SCI pathology. The top enriched functional categories include ‘inflammation response’, ‘neurological disease’, ‘cell death and survival’ and ‘nervous system development’. The top enriched pathways include LXR/RXR Activation and Atherosclerosis Signaling etc. Furthermore, we developed a systems-based analysis framework in order to identify key determinants in the global gene networks of the acute and sub-acute phases. Some candidate genes that we identified have been shown to play important roles in SCI, which demonstrates the validity of our approach. There are also many genes whose functions in SCI have not been well studied and can be further investigated by future experiments. We have also incorporated pharmacogenomic information into our analyses. Among the genes identified, the ones with existing drug information can be readily tested in SCI animal models. Conclusion: in this study we have described an example of how global gene profiling can be translated to screening genes of interest and generating new hypotheses. Additionally, the RNA-seq enables splicing isoform identification and the estimation of expression levels, thus providing useful information for increasing the specificity of drug design and reducing potential side effect. In summary, these results provide a valuable reference data resource for a better understanding of the SCI process in the acute and sub-acute phases. mRNA profiles of Acute/subacute phase Spinal Cord Injury sample from mice were generated by RNA-sequencing using Illumina HiSeq.
Project description:Spinal cord injury (SCI) is a devastating neurological condition for which there are currently no effective treatment options to restore function. A major obstacle to the development of new therapies is our fragmentary understanding of the coordinated pathophysiological processeses triggered by damage to the human spinal cord. An additional challenge to translation of preclinical therapies is the reliance of clinical trials on standardized neurological assessments to enrol and stratify patients, rather than objective injury biomarkers. Here, we describe a systems biology approach to integrate decades of small-scale experiments with unbiased, genome-wide gene expression from the human spinal cord, revealing a gene regulatory network signature of the pathophysiological response to SCI. Our integrative analyses converge on an evolutionarily conserved gene subnetwork enriched for genes associated with the response to SCI by small-scale experiments, and whose expression is upregulated in a severity-dependent manner following injury and downregulated in functional recovery. We validate the severity-dependent upregulation of this subnetwork in prospective transcriptomic and proteomic studies. Our analysis provides a systems-level view of the coordinated molecular processes activated in response to SCI. Further, our results nominate quantitative biomarkers of injury severity and functional recovery, with the potential to facilitate development and translation of novel therapies.