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. 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: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:Activation of microglia in the spinal cord following peripheral nerve injury is critical for the development of long-lasting pain hypersensitivity. However, it remains unknown whether distinct microglia subpopulations or states contribute to different stages of pain development and maintenance. Here, we demonstrate, using single-cell RNA-sequencing, that microglia transcriptional states differ at early and late time points following nerve injury. Male microglia show more proliferation and distinct transcriptional changes in response to nerve injury comparing to females. Apolipoprotein E (Apoe) was the top upregulated gene in microglia at chronic time points after nerve injury in mice and polymorphisms in the APOE in humans are associated with chronic pain. Single-cell analysis of human spinal cord microglia reveals a subpopulation with a disease-related transcriptional signature. Our data provide a detailed analysis of transcriptional states of mouse and human spinal cord microglia and identify a previously unrecognized role for ApoE in neuropathic pain.
Project description:The present study is intended to disclose the transcriptional profile of the temporal evolution through the different stages after SCI as well as the molecular processes underlying the NPC based-therapy in order to transcriptionally characterize its therapeutical mechanism. This transcriptional profile analysis of total RNA samples from spinal cord homogenates of adult rats (Sprague Dawley) provides tissular (tought not cell-type specific) information of the critical time points after the injury from 1 to 8 weeks (acute, sub-acute and early-chronic and late-chronic stages) which conferred a wide temporal coverage making it ideal for studying the temporal dynamics of SCI. Furthermore, we have evaluated the impact of intramedullary acute or subacute transplantation of NPCs over the transcriptional regulation of the spinal cord tissue in order to define the functional outcomes of the NPCs therapy.
Project description:Astrocytes are the predominant component of the scar and play crucial roles in spinal cord injury (SCI) at acute injury stage. Understanding the complex reactive astroglial contributions to SCI pathophysiologies is important for developing therapeutic strategies. To understand the mechanisms of astrogliosis in SCI, and to identify novel molecular targets to improve the injury environment and axonal regeneration, we have studied gene expression changes in SCI epicenter tissue using RNA-Seq at chronic stages (1 month and 3 months) in mouse moderate contusive injury models. Importantly, we have also FACS purified cells successfully from adult spinal cord using transgenic mice and generated RNA-Seq results for both acute (7 days) and chronic (1 month and 3 months) injury stages. The SCI RNA-Seq analysis provided valuable information on the gene expression in injury environment and astrocytes after SCI. In addition to protein coding genes, we were the first to systematically analyze the expression profiles of Long Noncoding RNAs (lncRNAs) in SCI and purified astrocytes. We have tested a number of candidates and found gene of interest Zeb2os which is a highly conserved lncRNA in human. Zeb2os expression has high correlation with an essential transcription factor (TF) in astrogliosis, Stat3, and its antisense protein coding gene Zeb2. Furthermore, our ChIP-seq experiment showed STAT3 bound to Zeb2 promoter region, thus Zeb2os may regulate Zeb2 and Stat3 directly or indirectly and STAT3 may regulate Zeb2 expression. Moreover, we have demonstrated for the first time by shRNA gene knockdown (KD) and functional assays that Zeb2os plays an important functional role in astrogliosis. We found Zeb2os KD in primary astrocytes affected a number of downstream genes by RNA-Seq, for example, Gfap, Zeb2, and Stat3 level decreased and reduced astrocyte proliferation.
Project description:Astrocytes are the predominant component of the scar and play crucial roles in spinal cord injury (SCI) at acute injury stage. Understanding the complex reactive astroglial contributions to SCI pathophysiologies is important for developing therapeutic strategies. To understand the mechanisms of astrogliosis in SCI, and to identify novel molecular targets to improve the injury environment and axonal regeneration, we have studied gene expression changes in SCI epicenter tissue using RNA-Seq at chronic stages (1 month and 3 months) in mouse moderate contusive injury models. Importantly, we have also FACS purified cells successfully from adult spinal cord using transgenic mice and generated RNA-Seq results for both acute (7 days) and chronic (1 month and 3 months) injury stages. The SCI RNA-Seq analysis provided valuable information on the gene expression in injury environment and astrocytes after SCI. In addition to protein coding genes, we were the first to systematically analyze the expression profiles of Long Noncoding RNAs (lncRNAs) in SCI and purified astrocytes. We have tested a number of candidates and found gene of interest Zeb2os which is a highly conserved lncRNA in human. Zeb2os expression has high correlation with an essential transcription factor (TF) in astrogliosis, Stat3, and its antisense protein coding gene Zeb2. Furthermore, our ChIP-seq experiment showed STAT3 bound to Zeb2 promoter region, thus Zeb2os may regulate Zeb2 and Stat3 directly or indirectly and STAT3 may regulate zeb2 expression. Moreover, we have demonstrated for the first time by shRNA gene knockdown (KD) and functional assays that Zeb2os plays an important functional role in astrogliosis. We found Zeb2os KD in primary astrocytes affected a number of downstream genes by RNA-Seq, for example, Gfap, Zeb2, and Stat3 level decreased and reduced astrocyte proliferation.
Project description:Recent studies in brain and spinal cord have revealed the heterogenous nature of astrocytes; however, how diverse constituents of astrocyte lineage cells are regulated in adult spinal cord after injury and contribute to regeneration remains elusive. We performed single-cell RNA-sequencing (scRNA-seq) of astrocyte lineage cells from sub-chronic spinal cord injury (SCI) models, identified and compared with the subpopulations in the acute stage data. We found the subpopulations with distinct functional enrichment and their identities defined by subpopulation-specific transcription factors and regulons. Our analyses revealed the molecular signature, location and morphologies of potential residential neural progenitors or neural stem cells in the adult spinal cord before and after injury, and the intermediate cells enriched in neuronal markers that could potentially transition into other subpopulations. The investigation of stage-specific cell-cell communications among astrocyte lineage cells and with other cell types in the tissue generated valuable insight into signaling pathway networks in SCI. This study has significantly expanded the knowledge of the heterogeneity and cell state transition of glial progenitors in adult spinal cord before and after injury.
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.
Project description:Background: Chronic spinal cord injury (SCI) remains one of the most debilitating neurological disorders and the majority of SCI patients are in the chronic phase. Previous studies of SCI that were limited by resources and technology have usually focused on few genes and pathways at a time. Thus, a comprehensive view of the complex molecular changes underlying SCI pathophysiology is needed. In particular, the biological roles of long non-coding RNAs (lncRNAs), a class of regulatory RNAs, have never been characterized systemically in SCI. Results: This study is the first to investigate alterations in the expression of both coding and long non-coding genes in the sub-chronic and chronic stages of SCI using RNA-Sequencing. Our data revealed differentially expressed genes, canonical pathways, and networks unique to particular time points or common to multiple time points in the progression of SCI. For example, a network of multiple critical genes responsible for astrogliosis and fibrosis was identified among differentially expressed genes common to three time points (1month, 3months, and 6 months after SCI). Moreover, the potential functions of rat lncRNAs in SCI were extensively analyzed. First, a comprehensive annotation database was compiled for rat lncRNAs that revealed several interesting characteristics of lncRNAs in the rat genome. Then, by correlating the temporal expression patterns of lncRNAs with those of protein-coding genes, we identified lncRNAs that are associated with functional categories such as signaling pathways, immune response, epigenetic modification, nervous system, and extracellular matrix. The expression patterns of some lncRNAs are highly correlated with those of their most proximal protein-coding genes, so it is possible that these lncRNAs regulate the expression of their protein-coding neighbors. Finally, we searched for transcription factor motifs enriched in the upstream regulatory regions of differentially expressed lncRNAs, and identified differentially expressed lncRNAs that are homologous to human genomic regions harboring molecular variants associated with human neurological diseases. Conclusions: Overall, our study provides an unprecedented resource for the study of sub-chronic and chronic SCI that will help the research community identify new molecular targets for future functional investigation.