Project description:RNA-seq analysis of astrocytes following spinal cord injury demonstrated an autologous injury-induced astroglial conversion towards neuronal lineage.
Project description:Astrocytes are taking the center stage in neurotrauma and neurological disease as they appear to play a dominant role in the inflammatory processes associated with these conditions. Previously, we reported that inhibiting nuclear factor kappa B (NF-kB) activation in astrocytes, by using a transgenic mouse model (GFAP-IκBα-dn mice), results in improved functional recovery following spinal cord injury (SCI), with increased white matter preservation and axonal sparing. In the present study we sought to determine whether this improvement, due to inhibiting NF-k-B activation in astrocytes, could be the result of enhanced oligogenesis in our GFAP-IκBα-dn mice. To gain insight into the underlying molecular mechanisms, we performed microarray analysis in naïve and 3 days, 3 and 6 weeks following SCI in GFAP-IκBα-dn and wild type (WT) littermate mice. Surprisingly, we found the largest number of genes differentially regulated between GFAP-IκBα-dn and WT mice 6 weeks post-injury. Interestingly, the data suggested that inhibiting astroglial NF-kB alters the inflammatory environment to support oligogenesis. Furthermore, confirmation of microarray data with qPCR and western blotting analysis and using BrdU labeling along with cell specific immunohistochemistry, confocal microscopy and quantitative cell counts, we demonstrate a significant increase in oligogenesis in GFAP-IκBα-dn following SCI. These studies suggest that therapeutic strategies targeting NF-kB activation in the CNS following SCI may promote oligogenesis and remyelination. Wild type (WT) mice - time points naïve, 3 days, 3 weeks, 6 weeks. Transgenic mice (TG) - time points naïve, 3 days, 3 weeks, 6 weeks.
Project description:Astrocytes are taking the center stage in neurotrauma and neurological disease as they appear to play a dominant role in the inflammatory processes associated with these conditions. Previously, we reported that inhibiting nuclear factor kappa B (NF-kB) activation in astrocytes, by using a transgenic mouse model (GFAP-IκBα-dn mice), results in improved functional recovery following spinal cord injury (SCI), with increased white matter preservation and axonal sparing. In the present study we sought to determine whether this improvement, due to inhibiting NF-k-B activation in astrocytes, could be the result of enhanced oligogenesis in our GFAP-IκBα-dn mice. To gain insight into the underlying molecular mechanisms, we performed microarray analysis in naïve and 3 days, 3 and 6 weeks following SCI in GFAP-IκBα-dn and wild type (WT) littermate mice. Surprisingly, we found the largest number of genes differentially regulated between GFAP-IκBα-dn and WT mice 6 weeks post-injury. Interestingly, the data suggested that inhibiting astroglial NF-kB alters the inflammatory environment to support oligogenesis. Furthermore, confirmation of microarray data with qPCR and western blotting analysis and using BrdU labeling along with cell specific immunohistochemistry, confocal microscopy and quantitative cell counts, we demonstrate a significant increase in oligogenesis in GFAP-IκBα-dn following SCI. These studies suggest that therapeutic strategies targeting NF-kB activation in the CNS following SCI may promote oligogenesis and remyelination.
Project description:We demonstrate for the first time that the extracellular matrix glycoprotein Tenascin-C regulates the expression of key patterning genes during late embryonic spinal cord development, leading to a timely maturation of gliogenic neural precursor cells. We first show that Tenascin-C is expressed by gliogenic neural precursor cells during late embryonic development. The loss of Tenascin-C leads to a sustained generation and delayed migration of Fibroblast growth factor receptor 3 expressing immature astrocytes in vivo. Furthermore, we could demonstrate an upregulation of Nk2 transcription factor related locus 2 (Nkx2.2) and its downstream target Sulfatase 1 in vivo. A dorsal expansion of Nkx2.2-positive cells within the ventral spinal cord indicates a potential progenitor cell domain shift. Moreover, Sulfatase 1 is known to regulate growth factor signalling by cleaving sulphate residues from heparan sulphate proteoglycans. Consistent with this possibility we observed changes in both Fibroblast growth factor 2 and Epidermal growth factor responsiveness of spinal cord neural precursor cells. Taken together our data clearly show that Tenascin-C promotes the astroglial lineage progression during spinal cord development. in total 6 probes: 3 replica of TNC_wt and 3 replica of TNC_ko
Project description:We demonstrate for the first time that the extracellular matrix glycoprotein Tenascin-C regulates the expression of key patterning genes during late embryonic spinal cord development, leading to a timely maturation of gliogenic neural precursor cells. We first show that Tenascin-C is expressed by gliogenic neural precursor cells during late embryonic development. The loss of Tenascin-C leads to a sustained generation and delayed migration of Fibroblast growth factor receptor 3 expressing immature astrocytes in vivo. Furthermore, we could demonstrate an upregulation of Nk2 transcription factor related locus 2 (Nkx2.2) and its downstream target Sulfatase 1 in vivo. A dorsal expansion of Nkx2.2-positive cells within the ventral spinal cord indicates a potential progenitor cell domain shift. Moreover, Sulfatase 1 is known to regulate growth factor signalling by cleaving sulphate residues from heparan sulphate proteoglycans. Consistent with this possibility we observed changes in both Fibroblast growth factor 2 and Epidermal growth factor responsiveness of spinal cord neural precursor cells. Taken together our data clearly show that Tenascin-C promotes the astroglial lineage progression during spinal cord development.
Project description:In the central nervous system (CNS) the transcription factor NF-kappaB is a key regulator of inflammation and secondary injury processes. Following trauma or disease, the expression of NF-kappaB-dependent genes is activated, leading to both protective and detrimental effects on CNS recovery. Here we show that transgenic inactivation of astroglial NF-kappaB in mice (GFAP-IkappaBalpha-dn mice) resulted in dramatic reduction of disease severity and improvement in functional recovery following EAE. This coincided with a higher presence of leukocytes in the cord and brain of transgenic mice at the chronic phase of the disease, when the functional recovery over WT mice was the most significant. We observed that expression of proinflammatory genes in both spinal cord and cerebellum was delayed and reduced, while the loss of neuronal-specific molecules essential for synaptic transmission was limited compared to WT mice. Furthermore, death of retinal ganglion cells in affected retinas was almost abolished, suggesting the activation of neuroprotective mechanisms. Our data indicate that inhibiting NF-kappaB in astrocytes results in neuroprotective effects following EAE, directly implicating astrocytes in the pathophysiology of this disease. Keywords: time course, EAE, transgenic mice, astrocytes, inflammation, cytokines, chemokines
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: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.