Objective:To determine if a cell cycle inhibitior, olomoucine, would decrease neuronal cell death, limit astroglial proliferation and production of inhibitory CSPGs, and eventually enhance the functional compensation ...Objective:To determine if a cell cycle inhibitior, olomoucine, would decrease neuronal cell death, limit astroglial proliferation and production of inhibitory CSPGs, and eventually enhance the functional compensation after SCI in rats. Methods: Three were used as un-operated controls and twelve as sham operated controls. Following spinal cord injury, 48 rats were randomly and blindly assigned to either olomoucine (n=24) or vehicle treatment (n=24) groups. Results: Up-regulations of cell cycle components were closely associated with neuronal cell death and astroglial proliferation as well as the production of CSPGs after SCI. Meanwhile, administration of olomoucine, a selective cell cycle kinase (CDK) inhibitor, has remarkably reduced the up-regulated cell cycle proteins and then decreased neuronal cell death, astroglial proliferation as well as accumulation of CSPGs. More importantly, the treatment with olomoucine has also increased expression of growth-associated proteins-43 (GAP-43), reduced the cavity formation, and improved functional deficits. Conclusion: Suppressing astroglial cell cycle in acute spinal cord injuries is beneficial to axonal growth. in turn, the future therapeutic strategies can be designed to achieve efficient axonal regeneration and functional compensation after traumatic CNS injury.展开更多
Reactive astrocytes contribute to glial scarring by rapid proliferation and up-regulation of glial fibrillary acidic protein (GFAP) expression and production of chondroitin sulfate proteoglycans (CSPGs). CSPGs play a ...Reactive astrocytes contribute to glial scarring by rapid proliferation and up-regulation of glial fibrillary acidic protein (GFAP) expression and production of chondroitin sulfate proteoglycans (CSPGs). CSPGs play a crucial role in formation of the glial scar, which takes over the lesion site following spinal cord injury (SCI). This process corresponds to the inflammatory response of macrophages, which polarize toward a dominant pro-inflammatory M1 phenotype following SCI. The M1 phenotype is known to release various cytotoxic compounds that exacerbate the glial scar, which in turn impedes tissue regeneration. Recent studies have shown that anti-inflammatory M2 macrophages play a role in allowing neurite extensions to occur, even across inhibitory substrates, and can lessen the degree of secondary damage. Based on earlier results demonstrating that keratin biomaterials may polarize macrophages toward an anti-inflammatory M2 phenotype, we test the hypothesis that these polarized macrophages will have the potential to indirectly effect astrogliosis. Using an in vitro model of reactive astrogliosis, macrophage-conditioned media from cells that have been cultured with soluble keratin for 24 hours or 7 days appears to decrease reactivity and associates CSPG production. These results are statistically similar to the control M2 macrophage conditioned media. A comparable collagen-conditioned macrophage media does not resolve astrocyte reactivity, while control M1 macrophage conditioned media results in an increase in GFAP expression. These data suggest keratin-derived macrophages are more functionally similar to M2 macrophages and that keratin treatment may aid in limiting secondary inflammatory-mediated damage.展开更多
Proteases comprise a variety of enzymes defined by their ability to catalytically hydrolyze the peptide bonds of other proteins,resulting in protein lysis.Cathepsins,specifically,encompass a class of at least twenty p...Proteases comprise a variety of enzymes defined by their ability to catalytically hydrolyze the peptide bonds of other proteins,resulting in protein lysis.Cathepsins,specifically,encompass a class of at least twenty proteases with potent endopeptidase activity.They are located subcellularly in lysosomes,organelles responsible for the cell’s degradative and autophagic processes,and are vital for normal lysosomal function.Although cathepsins are involved in a multitude of cell signaling activities,this chapter will focus on the role of cathepsins(with a special emphasis on Cathepsin B)in neuronal plasticity.We will broadly define what is known about regulation of cathepsins in the central nervous system and compare this with their dysregulation after injury or disease.Importantly,we will delineate what is currently known about the role of cathepsins in axon regeneration and plasticity after spinal cord injury.It is well established that normal cathepsin activity is integral to the function of lysosomes.Without normal lysosomal function,autophagy and other homeostatic cellular processes become dysregulated resulting in axon dystrophy.Furthermore,controlled activation of cathepsins at specialized neuronal structures such as axonal growth cones and dendritic spines have been positively implicated in their plasticity.This chapter will end with a perspective on the consequences of cathepsin dysregulation versus controlled,localized regulation to clarify how cathepsins can contribute to both neuronal plasticity and neurodegeneration.展开更多
Purpose:To investigate the mechanism of the termination of ocular dominance column plasticity by electrophysiologic analysis and 2-dimensional electrophoresis-mass spectrography(2-DE/MS).Methods:The changes in ocular ...Purpose:To investigate the mechanism of the termination of ocular dominance column plasticity by electrophysiologic analysis and 2-dimensional electrophoresis-mass spectrography(2-DE/MS).Methods:The changes in ocular dominance columns following monocular deprivation were electrophysiologically detected in 22-day-old,100-day-old and chondroitinase-perfused 100-day-old rats.Total protein of grey matter of the primary visual cortex was extracted and studied by 2-DE/MS from the three groups of rats.Results:Monocular deprivation may lead to shifts in ocular dominance columns in 22-day-old and chondroitinase-perfused 100-day-old rats,but not in 100-day-old rats.Four protein spots present in grey matter of the primary visual cortex in 100-day-old,but not in that of 22-day-old and chondroitinase-perfused rats,and mass spectrography identified two of these proteins.Conclusions:The electrophysiologic results show that ocular dominance column plasticity presents in 22-day-old rats,ends up in 100-day-old rats and restored in chondroitinase-perfused 100-day-old rats.2-DE/MS results show that phosphatidylethanolamine binding protein and glial fibrillary acidic protein delta may be associated with the termination of ocular dominance column plasticity in the rat,but need more evidence to confirm it.展开更多
基金the National Science Foundation of China(C30230140,C30400142)
文摘Objective:To determine if a cell cycle inhibitior, olomoucine, would decrease neuronal cell death, limit astroglial proliferation and production of inhibitory CSPGs, and eventually enhance the functional compensation after SCI in rats. Methods: Three were used as un-operated controls and twelve as sham operated controls. Following spinal cord injury, 48 rats were randomly and blindly assigned to either olomoucine (n=24) or vehicle treatment (n=24) groups. Results: Up-regulations of cell cycle components were closely associated with neuronal cell death and astroglial proliferation as well as the production of CSPGs after SCI. Meanwhile, administration of olomoucine, a selective cell cycle kinase (CDK) inhibitor, has remarkably reduced the up-regulated cell cycle proteins and then decreased neuronal cell death, astroglial proliferation as well as accumulation of CSPGs. More importantly, the treatment with olomoucine has also increased expression of growth-associated proteins-43 (GAP-43), reduced the cavity formation, and improved functional deficits. Conclusion: Suppressing astroglial cell cycle in acute spinal cord injuries is beneficial to axonal growth. in turn, the future therapeutic strategies can be designed to achieve efficient axonal regeneration and functional compensation after traumatic CNS injury.
文摘Reactive astrocytes contribute to glial scarring by rapid proliferation and up-regulation of glial fibrillary acidic protein (GFAP) expression and production of chondroitin sulfate proteoglycans (CSPGs). CSPGs play a crucial role in formation of the glial scar, which takes over the lesion site following spinal cord injury (SCI). This process corresponds to the inflammatory response of macrophages, which polarize toward a dominant pro-inflammatory M1 phenotype following SCI. The M1 phenotype is known to release various cytotoxic compounds that exacerbate the glial scar, which in turn impedes tissue regeneration. Recent studies have shown that anti-inflammatory M2 macrophages play a role in allowing neurite extensions to occur, even across inhibitory substrates, and can lessen the degree of secondary damage. Based on earlier results demonstrating that keratin biomaterials may polarize macrophages toward an anti-inflammatory M2 phenotype, we test the hypothesis that these polarized macrophages will have the potential to indirectly effect astrogliosis. Using an in vitro model of reactive astrogliosis, macrophage-conditioned media from cells that have been cultured with soluble keratin for 24 hours or 7 days appears to decrease reactivity and associates CSPG production. These results are statistically similar to the control M2 macrophage conditioned media. A comparable collagen-conditioned macrophage media does not resolve astrocyte reactivity, while control M1 macrophage conditioned media results in an increase in GFAP expression. These data suggest keratin-derived macrophages are more functionally similar to M2 macrophages and that keratin treatment may aid in limiting secondary inflammatory-mediated damage.
基金JS was funded by NINDS(NS25713)Brumagin-Nelson Fund+1 种基金Kaneko Family Fundthe Hong Kong Spinal Cord Injury Fund.
文摘Proteases comprise a variety of enzymes defined by their ability to catalytically hydrolyze the peptide bonds of other proteins,resulting in protein lysis.Cathepsins,specifically,encompass a class of at least twenty proteases with potent endopeptidase activity.They are located subcellularly in lysosomes,organelles responsible for the cell’s degradative and autophagic processes,and are vital for normal lysosomal function.Although cathepsins are involved in a multitude of cell signaling activities,this chapter will focus on the role of cathepsins(with a special emphasis on Cathepsin B)in neuronal plasticity.We will broadly define what is known about regulation of cathepsins in the central nervous system and compare this with their dysregulation after injury or disease.Importantly,we will delineate what is currently known about the role of cathepsins in axon regeneration and plasticity after spinal cord injury.It is well established that normal cathepsin activity is integral to the function of lysosomes.Without normal lysosomal function,autophagy and other homeostatic cellular processes become dysregulated resulting in axon dystrophy.Furthermore,controlled activation of cathepsins at specialized neuronal structures such as axonal growth cones and dendritic spines have been positively implicated in their plasticity.This chapter will end with a perspective on the consequences of cathepsin dysregulation versus controlled,localized regulation to clarify how cathepsins can contribute to both neuronal plasticity and neurodegeneration.
文摘Purpose:To investigate the mechanism of the termination of ocular dominance column plasticity by electrophysiologic analysis and 2-dimensional electrophoresis-mass spectrography(2-DE/MS).Methods:The changes in ocular dominance columns following monocular deprivation were electrophysiologically detected in 22-day-old,100-day-old and chondroitinase-perfused 100-day-old rats.Total protein of grey matter of the primary visual cortex was extracted and studied by 2-DE/MS from the three groups of rats.Results:Monocular deprivation may lead to shifts in ocular dominance columns in 22-day-old and chondroitinase-perfused 100-day-old rats,but not in 100-day-old rats.Four protein spots present in grey matter of the primary visual cortex in 100-day-old,but not in that of 22-day-old and chondroitinase-perfused rats,and mass spectrography identified two of these proteins.Conclusions:The electrophysiologic results show that ocular dominance column plasticity presents in 22-day-old rats,ends up in 100-day-old rats and restored in chondroitinase-perfused 100-day-old rats.2-DE/MS results show that phosphatidylethanolamine binding protein and glial fibrillary acidic protein delta may be associated with the termination of ocular dominance column plasticity in the rat,but need more evidence to confirm it.
