Mounting evidence supports an important role of chemokines, produced by spinal cord astrocytes, in promoting central sensitization and chronic pain. In particular, CCL2 （C-C motif chemokine ligand 2） has been shown ...Mounting evidence supports an important role of chemokines, produced by spinal cord astrocytes, in promoting central sensitization and chronic pain. In particular, CCL2 （C-C motif chemokine ligand 2） has been shown to enhance N-methyl-D-aspartate （NMDA）-induced currents in spinal outer lamina II （Iio） neurons. However, the exact molecular, synaptic, and cellular mechanisms by which CCL2 modulates central sensitization are still unclear. We found that spinal injection of the CCR2 antagonist RS504393 attenuated CCL2- and inflammation-induced hyperalgesia. Single-cell RT-PCR revealed CCR2 expres- sion in excitatory vesicular glutamate transporter subtype 2-positive （VGLUT2＋） neurons. CCL2 increased NMDA- induced currents in CCR2＋/VGLUT2＋ neurons in lamina IIo; it also enhanced the synaptic NMDA currents evoked by dorsal root stimulation; and furthermore, it increased the total and synaptic NMDA currents in somatostatin- expressing excitatory neurons. Finally, intrathecal RS504393 reversed the long-term potentiation evoked in the spinal cord by C-fiber stimulation. Our findings suggest that CCL2 directly modulates synaptic plasticity in CCR2- expressing excitatory neurons in spinal lamina Iio, and this underlies the generation of central sensitization in patho- logical pain.展开更多
Myelination by oligodendroglial cells （OLs） enables the propagation of action potentials along neuronal axons, which is essential for rapid information flow in the central nervous system. Besides saltatory conductio...Myelination by oligodendroglial cells （OLs） enables the propagation of action potentials along neuronal axons, which is essential for rapid information flow in the central nervous system. Besides saltatory conduction, the myelin sheath also protects axons against inflammatory and oxidative insults. Loss of myelin results in axonal damage and ultimately neuronal loss in demyelinating disorders. However, accumulating evidence indicates that OLs also provide support to neurons via mechanisms beyond the insulating function of myelin. More im- portantly, an increasing volume of reports indicates defects of OLs in numerous neurodegenerative diseases, sometimes even preceding neuronal loss in pre-symptomatic episodes, suggesting that OL pathology may be an important mechanism contributing to the initiation and/or progression of neurodegeneration. This review fo- cuses on the emerging picture of neuronal support by OLs in the pathogenesis of neurodegenerative disorders through diverse molecular and cellular mechanisms, including direct neuron-myelin interaction, metabolic sup- port by OLs, and neurotrophic factors produced by and/or acting on OLs.展开更多
Scar formation after spinal cord injury is regarded as an obstacle to axonal regeneration and functional recovery.Epothilone B provides moderate microtubule stabilization and is mainly used for anti-tumor therapy.It a...Scar formation after spinal cord injury is regarded as an obstacle to axonal regeneration and functional recovery.Epothilone B provides moderate microtubule stabilization and is mainly used for anti-tumor therapy.It also reduces scar tissue formation and promotes axonal regeneration after spinal cord injury.The aim of the present study was to investigate the effect and mechanism of the microtubule-stabilizing reagent epothilone B in decreasing fibrotic scarring through its action on pericytes after spinal cord injury.A rat model of spinal cord injury was established via dorsal complete transection at the T10 vertebra.The rats received an intraperitoneal injection of epothilone B（0.75 mg/kg） at 1 and 15 days post-injury in the epothilone B group or normal saline in the vehicle group.Neuron-glial antigen 2,platelet-derived growth factor receptor β,and fibronectin protein expression were dramatically lower in the epothilone B group than in the vehicle group,but β-tubulin protein expression was greater.Glial fibrillary acidic protein at the injury site was not affected by epothilone B treatment.The Basso,Beattie,and Bresnahan locomotor scores were significantly higher in the epothilone B group than in the vehicle group.The results of this study demonstrated that epothilone B reduced the number of pericytes,inhibited extracellular matrix formation,and suppressed scar formation after spinal cord injury.展开更多
Beta-nerve growth factor(β-NGF) is known to be a major leading cause of neuronal plasticity. To identify the possible action mechanisms of β-NGF gene therapy for sciatic nerve recovery, experimental dogs were random...Beta-nerve growth factor(β-NGF) is known to be a major leading cause of neuronal plasticity. To identify the possible action mechanisms of β-NGF gene therapy for sciatic nerve recovery, experimental dogs were randomly divided into control, pyridoxine, and pyridoxine + β-NGF groups. We observed chronological changes of morphology in the dorsal root ganglia in response to pyridoxine toxicity based on cresyl violet staining. The number of large neurons positive for cresyl violet was dramatically decreased after pyridoxine intoxication for 7 days in the dorsal root ganglia and the neuron number was gradually increased after pyridoxine withdrawal. In addition, we also investigated the effects of β-NGF gene therapy on neuronal plasticity in pyridoxine-induced neuropathic dogs. To accomplish this, tyrosine kinase receptor A(TrkA), βIII-tubulin and doublecortin(DCX) immunohistochemical staining was performed at 3 days after the last pyridoxine treatment. TrkA-immunoreactive neurons were dramatically decreased in the pyridoxine group compared to the control group, but strong TrkA immunoreactivity was observed in the small-sized dorsal root ganglia in this group. TrkA immunoreactivity in the dorsal root ganglia was similar between β-NGF and control groups. The numbers of βIII-tubulin-and DCX-immunoreactive cells decreased significantly in the pyridoxine group compared to the control group. However, the reduction of βIII-tubulin-and DCX-immunoreactive cells in the dorsal root ganglia in the β-NGF group was significantly ameliorated than that in the pyridoxine group. These results indicate that β-NGF gene therapy is a powerful treatment of pyridoxine-induced neuropathic damage by increasing the TrkA and DCX levels in the dorsal root ganglia. The experimental protocol was approved by the Institutional Animal Care and Use Committee(IACUC) of Seoul National University, South Korea(approval No. SNU-060623-1, SNU-091009-1) on June 23, 2006 and October 9, 2009, respectively.展开更多
AIM:To investigate whether neuron-glial antigen 2(NG2) could be an effective prognostic marker in hepatocellular carcinoma(HCC).METHODS:NG2 expression was semi-quantitatively scored from the immunohistochemistry(IHC) ...AIM:To investigate whether neuron-glial antigen 2(NG2) could be an effective prognostic marker in hepatocellular carcinoma(HCC).METHODS:NG2 expression was semi-quantitatively scored from the immunohistochemistry(IHC) data based on the number of positive cells and the staining intensity.A total of 132 HCC specimens and 96 adjacent noncancerous tissue samples were analyzed by IHC for NG2 protein expression.To confirm the NG2 expression levels observed by IHC,we measured NG2 expression in 30 randomly selected tumor and adjacent noncancerous tissue samples by quantitative real-time polymerase chain reaction and Western blot.The correlations between NG2 protein expression and the clinicopathological features of HCC patients were analyzed using the χ2 test.To assess the prognostic value of NG2 for HCC,the association between NG2 expression and survival was analyzed using the KaplanMeier method with the log-rank test.To further evaluate the prognostic value of NG2 expression,a Cox multivariate proportional hazards regression analysis was performed with all the variables to derive risk estimates related to disease-free and overall survival and to control for confounders.RESULTS:High NG2 expression was observed in significantly more primary tumor samples(63.6%; 84/132) compared with the adjacent noncancerous tissue samples(28.1%; 27/96)(P < 0.0001).Moreover,high NG2 protein expression was closely associated with tumor differentiation(χ2 = 9.436,P = 0.0089),recurrence(χ2 = 5.769,P = 0.0163),tumor-nodemetastasis(TNM) stage(χ2 = 8.976,P = 0.0027),and invasion(χ2 = 5.476,P = 0.0193).However,no significant relationship was observed between NG2 protein expression in HCC and other parameters,such as age,sex,tumor size,serum alpha fetoprotein(AFP),tumor number,or tumor capsule.The log-rank test indicated a significant difference in the overall survival of HCC patients with high NG2 expression compared with those with low NG2 expression(29.2% vs 9.5%,P < 0.001).Moreover,NG2 expression in HCC tissue significantly correlated wi展开更多
Myelination by oligodendrocytes in the central nervous system requires coordinated exocytosis and endocytosis of the major myelin protein, proteolipid protein （PLP）. Here, we demonstrated that a small GTPase, Rab27b...Myelination by oligodendrocytes in the central nervous system requires coordinated exocytosis and endocytosis of the major myelin protein, proteolipid protein （PLP）. Here, we demonstrated that a small GTPase, Rab27b, is involved in PLP trafficking in oligodendrocytes. We showed that PLP co-localized with Rab27b in late endosomes/lysosomes in oligodendrocytes. Short hairpin- mediated knockdown of Rab27b not only reduced lysosomal exocytosis but also greatly diminished the surface expression of PLP in oligodendrocytes. In addition, knockdown of Rab27b reduced the myelin-like membranes induced by co-culture of oligodendrocytes and neurons. Our data suggest that Rab27b is involved in myelin biogenesis by regulating PLP transport from late endosomes/ lysosomes to the cell membrane in oligodendrocytes.展开更多
Previous studies have shown that CCL2(C-C motif chemokine ligand 2)induces chronic pain,but the exact mechanisms are still unknown.Here,we established models to explore the potential mechanisms.Behavioral experiments ...Previous studies have shown that CCL2(C-C motif chemokine ligand 2)induces chronic pain,but the exact mechanisms are still unknown.Here,we established models to explore the potential mechanisms.Behavioral experiments revealed that an antagonist of extracellular signal-regulated kinase(ERK)inhibited not only CCL2-induced inflammatory pain,but also pain responses induced by complete Freund’s adjuvant.We posed the question of the intracellular signaling cascade involved.Subsequent experiments showed that CCL2 up-regulated the expression of phosphorylated ERK(pERK)and N-methyl D-aspartate receptor[NMDAR]subtype 2B(GluN2B);meanwhile,antagonists of CCR2 and ERK effectively reversed these phenomena.Whole-cell patchclamp recordings revealed that CCL2 enhanced the NMDAR-induced currents via activating the pERK pathway,which was blocked by antagonists of GluN2B and ERK.In summary,we demonstrate that CCL2 directly interacts with CCR2 to enhance NMDAR-induced currents,eventually leading to inflammatory pain mainly through the CCL2-CCR2-pERK-GluN2B pathway.展开更多
Macroscopic spatiotemporal patterns arising in grey matter may explain the clinical manifestations of several functional neurological syndromes (migraine aura, epilepsies). Detailed descriptions of these patterns in c...Macroscopic spatiotemporal patterns arising in grey matter may explain the clinical manifestations of several functional neurological syndromes (migraine aura, epilepsies). Detailed descriptions of these patterns in central grey matter and their physicochemical or pharmacological manipulations can be useful in many scientific fields ranging from drug design to functional brain imaging. These evanescent dynamic structures are electrochemical in nature and show macroscopic tissue polarization due to coupled and macroscopic flow of ions and water across, along and between neuronal and glial membranes. So far the importance of the water flow in the CNS functional syndromes has been examined by manipulations of water channels aquaporines (AQP). In this paper we show the result of substituting H2O for D2O in retinal spreading depression experiments. This inverts the present logic by changing the flow in the water channels in intact tissue and observing the evolution of electrochemical patterns and recording the optical profiles of excitation waves in isolated chick retinas. D2O flow through AQPs is ~20% slower than that of H2O. The slower flux disturbs the tight coupling between ion and water flows across membranes and slowdown the Na-KATPase rate of change with metabolic consequences for the tissue. The whole tissue excitability shifts in a non-stationary manner toward a non-excitable state.展开更多
基金supported by grants from the National Natural Science Foundation of China(31400949,81502102,31471059,81371498,and 31371121)NIH R01,USA Grants(DE17794,DE22743,and NS87988)
文摘Mounting evidence supports an important role of chemokines, produced by spinal cord astrocytes, in promoting central sensitization and chronic pain. In particular, CCL2 （C-C motif chemokine ligand 2） has been shown to enhance N-methyl-D-aspartate （NMDA）-induced currents in spinal outer lamina II （Iio） neurons. However, the exact molecular, synaptic, and cellular mechanisms by which CCL2 modulates central sensitization are still unclear. We found that spinal injection of the CCR2 antagonist RS504393 attenuated CCL2- and inflammation-induced hyperalgesia. Single-cell RT-PCR revealed CCR2 expres- sion in excitatory vesicular glutamate transporter subtype 2-positive （VGLUT2＋） neurons. CCL2 increased NMDA- induced currents in CCR2＋/VGLUT2＋ neurons in lamina IIo; it also enhanced the synaptic NMDA currents evoked by dorsal root stimulation; and furthermore, it increased the total and synaptic NMDA currents in somatostatin- expressing excitatory neurons. Finally, intrathecal RS504393 reversed the long-term potentiation evoked in the spinal cord by C-fiber stimulation. Our findings suggest that CCL2 directly modulates synaptic plasticity in CCR2- expressing excitatory neurons in spinal lamina Iio, and this underlies the generation of central sensitization in patho- logical pain.
基金supported by NIH grants NS070526 and NS056097 to YF,and NS070526-01A1S1 to MDMANB and MDM were supported by NIH training grant T32GM008602
文摘Myelination by oligodendroglial cells （OLs） enables the propagation of action potentials along neuronal axons, which is essential for rapid information flow in the central nervous system. Besides saltatory conduction, the myelin sheath also protects axons against inflammatory and oxidative insults. Loss of myelin results in axonal damage and ultimately neuronal loss in demyelinating disorders. However, accumulating evidence indicates that OLs also provide support to neurons via mechanisms beyond the insulating function of myelin. More im- portantly, an increasing volume of reports indicates defects of OLs in numerous neurodegenerative diseases, sometimes even preceding neuronal loss in pre-symptomatic episodes, suggesting that OL pathology may be an important mechanism contributing to the initiation and/or progression of neurodegeneration. This review fo- cuses on the emerging picture of neuronal support by OLs in the pathogenesis of neurodegenerative disorders through diverse molecular and cellular mechanisms, including direct neuron-myelin interaction, metabolic sup- port by OLs, and neurotrophic factors produced by and/or acting on OLs.
基金supported by a grant from the Science and Technology Developing Program of Shandong Provincial Government of China,No.2010GSF10254a grant from the Medical and Health Science and Technology Plan Project of Shandong Province of China,No.2015WS0504
文摘Scar formation after spinal cord injury is regarded as an obstacle to axonal regeneration and functional recovery.Epothilone B provides moderate microtubule stabilization and is mainly used for anti-tumor therapy.It also reduces scar tissue formation and promotes axonal regeneration after spinal cord injury.The aim of the present study was to investigate the effect and mechanism of the microtubule-stabilizing reagent epothilone B in decreasing fibrotic scarring through its action on pericytes after spinal cord injury.A rat model of spinal cord injury was established via dorsal complete transection at the T10 vertebra.The rats received an intraperitoneal injection of epothilone B（0.75 mg/kg） at 1 and 15 days post-injury in the epothilone B group or normal saline in the vehicle group.Neuron-glial antigen 2,platelet-derived growth factor receptor β,and fibronectin protein expression were dramatically lower in the epothilone B group than in the vehicle group,but β-tubulin protein expression was greater.Glial fibrillary acidic protein at the injury site was not affected by epothilone B treatment.The Basso,Beattie,and Bresnahan locomotor scores were significantly higher in the epothilone B group than in the vehicle group.The results of this study demonstrated that epothilone B reduced the number of pericytes,inhibited extracellular matrix formation,and suppressed scar formation after spinal cord injury.
基金supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT&Future Planning(No.NRF-2017R1A1A1A05000762)Cooperative Research Program for Agriculture Science and Technology Development,Rural Development Administration,Republic of Korea(No.PJ01395602 both to JYC)
文摘Beta-nerve growth factor(β-NGF) is known to be a major leading cause of neuronal plasticity. To identify the possible action mechanisms of β-NGF gene therapy for sciatic nerve recovery, experimental dogs were randomly divided into control, pyridoxine, and pyridoxine + β-NGF groups. We observed chronological changes of morphology in the dorsal root ganglia in response to pyridoxine toxicity based on cresyl violet staining. The number of large neurons positive for cresyl violet was dramatically decreased after pyridoxine intoxication for 7 days in the dorsal root ganglia and the neuron number was gradually increased after pyridoxine withdrawal. In addition, we also investigated the effects of β-NGF gene therapy on neuronal plasticity in pyridoxine-induced neuropathic dogs. To accomplish this, tyrosine kinase receptor A(TrkA), βIII-tubulin and doublecortin(DCX) immunohistochemical staining was performed at 3 days after the last pyridoxine treatment. TrkA-immunoreactive neurons were dramatically decreased in the pyridoxine group compared to the control group, but strong TrkA immunoreactivity was observed in the small-sized dorsal root ganglia in this group. TrkA immunoreactivity in the dorsal root ganglia was similar between β-NGF and control groups. The numbers of βIII-tubulin-and DCX-immunoreactive cells decreased significantly in the pyridoxine group compared to the control group. However, the reduction of βIII-tubulin-and DCX-immunoreactive cells in the dorsal root ganglia in the β-NGF group was significantly ameliorated than that in the pyridoxine group. These results indicate that β-NGF gene therapy is a powerful treatment of pyridoxine-induced neuropathic damage by increasing the TrkA and DCX levels in the dorsal root ganglia. The experimental protocol was approved by the Institutional Animal Care and Use Committee(IACUC) of Seoul National University, South Korea(approval No. SNU-060623-1, SNU-091009-1) on June 23, 2006 and October 9, 2009, respectively.
基金Supported by National Natural Science Foundation of China,No.81170425 and No.81071979Hepatobiliary Surgery Department of the Southwest Hospital(Chongqing,China)Third Military Medical University(Chongqing,China)
文摘AIM:To investigate whether neuron-glial antigen 2(NG2) could be an effective prognostic marker in hepatocellular carcinoma(HCC).METHODS:NG2 expression was semi-quantitatively scored from the immunohistochemistry(IHC) data based on the number of positive cells and the staining intensity.A total of 132 HCC specimens and 96 adjacent noncancerous tissue samples were analyzed by IHC for NG2 protein expression.To confirm the NG2 expression levels observed by IHC,we measured NG2 expression in 30 randomly selected tumor and adjacent noncancerous tissue samples by quantitative real-time polymerase chain reaction and Western blot.The correlations between NG2 protein expression and the clinicopathological features of HCC patients were analyzed using the χ2 test.To assess the prognostic value of NG2 for HCC,the association between NG2 expression and survival was analyzed using the KaplanMeier method with the log-rank test.To further evaluate the prognostic value of NG2 expression,a Cox multivariate proportional hazards regression analysis was performed with all the variables to derive risk estimates related to disease-free and overall survival and to control for confounders.RESULTS:High NG2 expression was observed in significantly more primary tumor samples(63.6%; 84/132) compared with the adjacent noncancerous tissue samples(28.1%; 27/96)(P < 0.0001).Moreover,high NG2 protein expression was closely associated with tumor differentiation(χ2 = 9.436,P = 0.0089),recurrence(χ2 = 5.769,P = 0.0163),tumor-nodemetastasis(TNM) stage(χ2 = 8.976,P = 0.0027),and invasion(χ2 = 5.476,P = 0.0193).However,no significant relationship was observed between NG2 protein expression in HCC and other parameters,such as age,sex,tumor size,serum alpha fetoprotein(AFP),tumor number,or tumor capsule.The log-rank test indicated a significant difference in the overall survival of HCC patients with high NG2 expression compared with those with low NG2 expression(29.2% vs 9.5%,P < 0.001).Moreover,NG2 expression in HCC tissue significantly correlated wi
基金supported by the National Natural Science Foundation of China(31071251 and 81471255)the National Basic Research Development Program of China(2014CB542202)+2 种基金the Basic Research Program of the Department of Education,Jiangsu Province,China(14KJA310004)a Natural Science Research Project of Nantong Science and Technology Bureau,Jiangsu Province,China(HS2013014)the Natural Science Research Project of Nantong University,Jiangsu Province,China(12Z045,13Z008)
文摘Myelination by oligodendrocytes in the central nervous system requires coordinated exocytosis and endocytosis of the major myelin protein, proteolipid protein （PLP）. Here, we demonstrated that a small GTPase, Rab27b, is involved in PLP trafficking in oligodendrocytes. We showed that PLP co-localized with Rab27b in late endosomes/lysosomes in oligodendrocytes. Short hairpin- mediated knockdown of Rab27b not only reduced lysosomal exocytosis but also greatly diminished the surface expression of PLP in oligodendrocytes. In addition, knockdown of Rab27b reduced the myelin-like membranes induced by co-culture of oligodendrocytes and neurons. Our data suggest that Rab27b is involved in myelin biogenesis by regulating PLP transport from late endosomes/ lysosomes to the cell membrane in oligodendrocytes.
基金grants from the National Natural Science Foundation of China(81870867,31671088,31471059,and 81502102)the Natural Science Foundation of Shaanxi Province,China(2019SF-071 and 2017ZDJC-01)。
文摘Previous studies have shown that CCL2(C-C motif chemokine ligand 2)induces chronic pain,but the exact mechanisms are still unknown.Here,we established models to explore the potential mechanisms.Behavioral experiments revealed that an antagonist of extracellular signal-regulated kinase(ERK)inhibited not only CCL2-induced inflammatory pain,but also pain responses induced by complete Freund’s adjuvant.We posed the question of the intracellular signaling cascade involved.Subsequent experiments showed that CCL2 up-regulated the expression of phosphorylated ERK(pERK)and N-methyl D-aspartate receptor[NMDAR]subtype 2B(GluN2B);meanwhile,antagonists of CCR2 and ERK effectively reversed these phenomena.Whole-cell patchclamp recordings revealed that CCL2 enhanced the NMDAR-induced currents via activating the pERK pathway,which was blocked by antagonists of GluN2B and ERK.In summary,we demonstrate that CCL2 directly interacts with CCR2 to enhance NMDAR-induced currents,eventually leading to inflammatory pain mainly through the CCL2-CCR2-pERK-GluN2B pathway.
文摘Macroscopic spatiotemporal patterns arising in grey matter may explain the clinical manifestations of several functional neurological syndromes (migraine aura, epilepsies). Detailed descriptions of these patterns in central grey matter and their physicochemical or pharmacological manipulations can be useful in many scientific fields ranging from drug design to functional brain imaging. These evanescent dynamic structures are electrochemical in nature and show macroscopic tissue polarization due to coupled and macroscopic flow of ions and water across, along and between neuronal and glial membranes. So far the importance of the water flow in the CNS functional syndromes has been examined by manipulations of water channels aquaporines (AQP). In this paper we show the result of substituting H2O for D2O in retinal spreading depression experiments. This inverts the present logic by changing the flow in the water channels in intact tissue and observing the evolution of electrochemical patterns and recording the optical profiles of excitation waves in isolated chick retinas. D2O flow through AQPs is ~20% slower than that of H2O. The slower flux disturbs the tight coupling between ion and water flows across membranes and slowdown the Na-KATPase rate of change with metabolic consequences for the tissue. The whole tissue excitability shifts in a non-stationary manner toward a non-excitable state.
