Spinal cord injury involves non-reversible damage to the central nervous system that is characterized by limited regenerative capacity and secondary inflammatory damage.The expression of the C-C motif chemokine ligand...Spinal cord injury involves non-reversible damage to the central nervous system that is characterized by limited regenerative capacity and secondary inflammatory damage.The expression of the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis exhibits significant differences before and after injury.Recent studies have revealed that the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis is closely associated with secondary inflammatory responses and the recruitment of immune cells following spinal cord injury,suggesting that this axis is a novel target and regulatory control point for treatment.This review comprehensively examines the therapeutic strategies targeting the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis,along with the regenerative and repair mechanisms linking the axis to spinal cord injury.Additionally,we summarize the upstream and downstream inflammatory signaling pathways associated with spinal cord injury and the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis.This review primarily elaborates on therapeutic strategies that target the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis and the latest progress of research on antagonistic drugs,along with the approaches used to exploit new therapeutic targets within the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis and the development of targeted drugs.Nevertheless,there are presently no clinical studies relating to spinal cord injury that are focusing on the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis.This review aims to provide new ideas and therapeutic strategies for the future treatment of spinal cord injury.展开更多
Objective:This study was performed to explore the possible changes of the serum levels of the cytokines including interleukin 1α(IL-1α),chemokine monocyte chemotactic protein 1(also known as chemokine[C-C motif]liga...Objective:This study was performed to explore the possible changes of the serum levels of the cytokines including interleukin 1α(IL-1α),chemokine monocyte chemotactic protein 1(also known as chemokine[C-C motif]ligand 2[CCL2]),and C-X-C motif chemokine ligand 2(CXCL2)in patients with pemphigus.Methods:The expression levels of IL-1α,CCL2,and CXCL2 in the serum of 57 patients with pemphigus PV(including 42 patients in progressive stage and 15 patients in remission stage)and 31 healthy controls were examined by enzyme-linked immunosorbent assay.The indepent-samples t-test was used to compare the two groups.Oneway analysis of variance was used for multiple-group comparisons,and the post-hoc least significant difference test was used to detect differences among multiple groups.Results:The serum expression levels of CCL2 and IL-1a were all significantly higher in the patients in progressive stage than in the controls([2.69±0.23]ng/mL vs.[2.55±0.28]ng/mL,P=0.043;[0.62±0.27]ng/mL vs.[0.48±0.23]ng/mL,P=0.038,respectively).In addition,the serum expression level of CXCL2 was significantly higher in patients in progressive stage than in in the remission stage([61.70±46.38]ng/mL vs.[24.97±18.46]ng/mL,P=0.037).Sex,disease classification,disease severity,treatment,and mucosal involvement had no significant influence on the expression of IL-1α,CCL2,or CXCL2 in the serum of patients groups and controls(all P>0.05).Conclusion:IL-1α,CCL2,and CXCL2 are heavily involved in the occurrence and development of pemphigus and may be related to the activity of the disease.展开更多
Spinal cord injury causes accumulation of a large number of leukocytes at the lesion site where they contribute to excessive inflammation.Overproduced chemokines are responsible for the migratory process of the leukoc...Spinal cord injury causes accumulation of a large number of leukocytes at the lesion site where they contribute to excessive inflammation.Overproduced chemokines are responsible for the migratory process of the leukocytes,but the regulatory mechanism underlying the production of chemokines from resident cells of the spinal cord has not been fully elucidated.We examined the protein levels of macrophage migration inhibitory factor and chemokine C-C motif chemokine ligand 2 in a spinal cord contusion model at different time points following spinal cord injury.The elevation of macrophage migration inhibitory factor at the lesion site coincided with the increase of chemokine C-C motif chemokine ligand 2 abundance in astrocytes.Stimulation of primary cultured astrocytes with different concentrations of macrophage migration inhibitory factor recombinant protein induced chemokine C-C motif chemokine ligand 2 production from the cells,and the macrophage migration inhibitory factor inhibitor 4-iodo-6-phenylpyrimidine attenuated the stimulatory effect.Further investigation into the underlying mechanism on macrophage migration inhibitory factor-mediated astrocytic production of chemokine C-C motif chemokine ligand 2 revealed that macrophage migration inhibitory factor activated intracellular JNK signaling through binding with CD74 receptor.Administration of the macrophage migration inhibitory factor inhibitor 4-iodo-6-phenylpyrimidine following spinal cord injury resulted in the reduction of chemokine C-C motif chemokine ligand 2-recruited microglia/macrophages at the lesion site and remarkably improved the hindlimb locomotor function of rats.Our results have provided insights into the functions of astrocyte-activated chemokines in the recruitment of leukocytes and may be beneficial to develop interventions targeting chemokine C-C motif chemokine ligand 2 for neuroinflammation after spinal cord injury.展开更多
Objective:Aconite is a traditional Chinese herbal medicine that has been found to inhibit the development of liver cancer;however,its exact molecular mechanisms in this process remain unclear.This study explores how a...Objective:Aconite is a traditional Chinese herbal medicine that has been found to inhibit the development of liver cancer;however,its exact molecular mechanisms in this process remain unclear.This study explores how aconite aqueous extract(AAE)inhibits hepatocellular carcinoma(HCC).Methods:An in vivo mouse model of subcutaneous liver cancer was established.After AAE treatment,immunohistochemistry(IHC)was used to determine the effect of AAE on natural killer(NK)cells.Subsequently,C57BL/6 mice were used to establish the subcutaneous tumor model,and a group of these mice were treated with anti-PK163 antibody to remove NK cells,which was verified by flow cytometry and IHC.The effect of AAE on the proliferation of HCC cells in vitro was determined using cell counting kit-8.The effect of AAE on chemokine production in HCC cells was measured using real-time quantitative polymerase chain reaction and an enzyme-linked immunosorbent assay.The effect of AAE on the migration of NK cells was determined using a transwell assay.Finally,the molecular mechanism was investigated using the Western blotting method.Results:We demonstrated that the ability of AAE to induce overexpression of the cytokine C–C motif chemokine ligand 2(CCL2)in HCC cells is fundamental to the infiltration of NK cells into the tumor bed.Mechanistically,we found that the upregulation of CCL2 was achieved by the activation of c-Jun Nterminal kinase but not extracellular regulated protein kinase or p38.Conclusion:Our findings suggest that AAE can be used as an effective immune adjuvant to enhance antitumor immunity by increasing NK cell infiltration into tumors,which could help to improve the efficacy of HCC treatments.展开更多
BACKGROUND Ulcerative colitis(UC)is an inflammatory bowel disease that is difficult to diagnose and treat.To date,the degree of inflammation in patients with UC has mainly been determined by measuring the levels of no...BACKGROUND Ulcerative colitis(UC)is an inflammatory bowel disease that is difficult to diagnose and treat.To date,the degree of inflammation in patients with UC has mainly been determined by measuring the levels of nonspecific indicators,such as C-reactive protein and the erythrocyte sedimentation rate,but these indicators have an unsatisfactory specificity.In this study,we performed bioinformatics analysis using data from the National Center for Biotechnology Information-Gene Expression Omnibus(NCBI-GEO)databases and verified the selected core genes in a mouse model of dextran sulfate sodium(DSS)-induced colitis.AIM To identify UC-related differentially expressed genes(DEGs)using a bioinformatics analysis and verify them in vivo and to identify novel biomarkers and the underlying mechanisms of UC.METHODS Two microarray datasets from the NCBI-GEO database were used,and DEGs between patients with UC and healthy controls were analyzed using GEO2R and Venn diagrams.We annotated these genes based on their functions and signaling pathways,and then protein-protein interactions(PPIs)were identified using the Search Tool for the Retrieval of Interacting Genes.The data were further analyzed with Cytoscape software and the Molecular Complex Detection(MCODE)app.The core genes were selected and a Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis was performed.Finally,colitis model mice were established by administering DSS,and the top three core genes were verified in colitis mice using real-time polymerase chain reaction(PCR).RESULTS One hundred and seventy-seven DEGs,118 upregulated and 59 downregulated,were initially identified from the GEO2R analysis and predominantly participated in inflammation-related pathways.Seven clusters with close interactions in UC formed:Seventeen core genes were upregulated[C-X-C motif chemokine ligand 13(CXCL13),C-X-C motif chemokine receptor 2(CXCR2),CXCL9,CXCL5,C-C motif chemokine ligand 18,interleukin 1 beta,matrix metallopeptidase 9,CXCL3,formyl peptide receptor 1,comple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
Objective:To explore the modulation of mesenchymal stem cells(MSCs)on T helper 17(Th17)cells in systemic lupus erythematosus(SLE)and underlying mechanism.Methods:The concentration of matrix metalloproteinases(MMPs),CC...Objective:To explore the modulation of mesenchymal stem cells(MSCs)on T helper 17(Th17)cells in systemic lupus erythematosus(SLE)and underlying mechanism.Methods:The concentration of matrix metalloproteinases(MMPs),CC chemokine ligand-2(CCL2),and interleukin-17(IL-17)in the serum of SLE patients and mice were detected by enzyme-linked immunosorbent assay.The expression of CCR2 and IL-17 of T lymphocytes were determined by flow cytometry.The effects of MSCs on Th17 cells were analyzed in lupus mice and coculture system in vitro.Results:The levels of MMPs,CCL2,IL-17,CCR2,and percentages of Th17 cells were significantly increased in SLE patients.These molecules and numbers of Th17 cells were downregulated by umbilical cord-derived MSCs(UC-MSCs)which relieve SLE disease.CCL2 neutralizing antibody blocked the effects of MSCs on Th17 cells.MMPs reversed the function of CCL2.Conclusion:The beneficial effects of MSCs on SLE patients rely on secreting MMPs,which reverse the activity of CCL2 to inhibit Th17 cells,suggesting the crucial MSCs–MMP–CCL2–CCR2–Th17–IL-17 pathway in SLE.展开更多
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
基金supported by the National Natural Science Foundation of China(Key Program),No.11932013the National Natural Science Foundation of China(General Program),No.82272255+2 种基金Armed Police Force High-Level Science and Technology Personnel ProjectThe Armed Police Force Focuses on Supporting Scientific and Technological Innovation TeamsKey Project of Tianjin Science and Technology Plan,No.20JCZDJC00570(all to XC)。
文摘Spinal cord injury involves non-reversible damage to the central nervous system that is characterized by limited regenerative capacity and secondary inflammatory damage.The expression of the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis exhibits significant differences before and after injury.Recent studies have revealed that the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis is closely associated with secondary inflammatory responses and the recruitment of immune cells following spinal cord injury,suggesting that this axis is a novel target and regulatory control point for treatment.This review comprehensively examines the therapeutic strategies targeting the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis,along with the regenerative and repair mechanisms linking the axis to spinal cord injury.Additionally,we summarize the upstream and downstream inflammatory signaling pathways associated with spinal cord injury and the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis.This review primarily elaborates on therapeutic strategies that target the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis and the latest progress of research on antagonistic drugs,along with the approaches used to exploit new therapeutic targets within the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis and the development of targeted drugs.Nevertheless,there are presently no clinical studies relating to spinal cord injury that are focusing on the C-C motif chemokine ligand 2/C-C motif chemokine receptor 2 axis.This review aims to provide new ideas and therapeutic strategies for the future treatment of spinal cord injury.
文摘Objective:This study was performed to explore the possible changes of the serum levels of the cytokines including interleukin 1α(IL-1α),chemokine monocyte chemotactic protein 1(also known as chemokine[C-C motif]ligand 2[CCL2]),and C-X-C motif chemokine ligand 2(CXCL2)in patients with pemphigus.Methods:The expression levels of IL-1α,CCL2,and CXCL2 in the serum of 57 patients with pemphigus PV(including 42 patients in progressive stage and 15 patients in remission stage)and 31 healthy controls were examined by enzyme-linked immunosorbent assay.The indepent-samples t-test was used to compare the two groups.Oneway analysis of variance was used for multiple-group comparisons,and the post-hoc least significant difference test was used to detect differences among multiple groups.Results:The serum expression levels of CCL2 and IL-1a were all significantly higher in the patients in progressive stage than in the controls([2.69±0.23]ng/mL vs.[2.55±0.28]ng/mL,P=0.043;[0.62±0.27]ng/mL vs.[0.48±0.23]ng/mL,P=0.038,respectively).In addition,the serum expression level of CXCL2 was significantly higher in patients in progressive stage than in in the remission stage([61.70±46.38]ng/mL vs.[24.97±18.46]ng/mL,P=0.037).Sex,disease classification,disease severity,treatment,and mucosal involvement had no significant influence on the expression of IL-1α,CCL2,or CXCL2 in the serum of patients groups and controls(all P>0.05).Conclusion:IL-1α,CCL2,and CXCL2 are heavily involved in the occurrence and development of pemphigus and may be related to the activity of the disease.
基金supported by the China Postdoctoral Science Foundation,No.2020M681689(to YMH)the Basic Scientific Research Projects of Nantong,Nos.JC2020015(to HX)and JC2020041(to YMH)。
文摘Spinal cord injury causes accumulation of a large number of leukocytes at the lesion site where they contribute to excessive inflammation.Overproduced chemokines are responsible for the migratory process of the leukocytes,but the regulatory mechanism underlying the production of chemokines from resident cells of the spinal cord has not been fully elucidated.We examined the protein levels of macrophage migration inhibitory factor and chemokine C-C motif chemokine ligand 2 in a spinal cord contusion model at different time points following spinal cord injury.The elevation of macrophage migration inhibitory factor at the lesion site coincided with the increase of chemokine C-C motif chemokine ligand 2 abundance in astrocytes.Stimulation of primary cultured astrocytes with different concentrations of macrophage migration inhibitory factor recombinant protein induced chemokine C-C motif chemokine ligand 2 production from the cells,and the macrophage migration inhibitory factor inhibitor 4-iodo-6-phenylpyrimidine attenuated the stimulatory effect.Further investigation into the underlying mechanism on macrophage migration inhibitory factor-mediated astrocytic production of chemokine C-C motif chemokine ligand 2 revealed that macrophage migration inhibitory factor activated intracellular JNK signaling through binding with CD74 receptor.Administration of the macrophage migration inhibitory factor inhibitor 4-iodo-6-phenylpyrimidine following spinal cord injury resulted in the reduction of chemokine C-C motif chemokine ligand 2-recruited microglia/macrophages at the lesion site and remarkably improved the hindlimb locomotor function of rats.Our results have provided insights into the functions of astrocyte-activated chemokines in the recruitment of leukocytes and may be beneficial to develop interventions targeting chemokine C-C motif chemokine ligand 2 for neuroinflammation after spinal cord injury.
基金funded by the National Natural Science Foundation of China(No.81774244).
文摘Objective:Aconite is a traditional Chinese herbal medicine that has been found to inhibit the development of liver cancer;however,its exact molecular mechanisms in this process remain unclear.This study explores how aconite aqueous extract(AAE)inhibits hepatocellular carcinoma(HCC).Methods:An in vivo mouse model of subcutaneous liver cancer was established.After AAE treatment,immunohistochemistry(IHC)was used to determine the effect of AAE on natural killer(NK)cells.Subsequently,C57BL/6 mice were used to establish the subcutaneous tumor model,and a group of these mice were treated with anti-PK163 antibody to remove NK cells,which was verified by flow cytometry and IHC.The effect of AAE on the proliferation of HCC cells in vitro was determined using cell counting kit-8.The effect of AAE on chemokine production in HCC cells was measured using real-time quantitative polymerase chain reaction and an enzyme-linked immunosorbent assay.The effect of AAE on the migration of NK cells was determined using a transwell assay.Finally,the molecular mechanism was investigated using the Western blotting method.Results:We demonstrated that the ability of AAE to induce overexpression of the cytokine C–C motif chemokine ligand 2(CCL2)in HCC cells is fundamental to the infiltration of NK cells into the tumor bed.Mechanistically,we found that the upregulation of CCL2 was achieved by the activation of c-Jun Nterminal kinase but not extracellular regulated protein kinase or p38.Conclusion:Our findings suggest that AAE can be used as an effective immune adjuvant to enhance antitumor immunity by increasing NK cell infiltration into tumors,which could help to improve the efficacy of HCC treatments.
基金Chinese Medicine Inheritance and Innovation“One Hundred Million”Talent Project Qihuang Scholar(to Li JX)The National Key R&D Program of China during the 13th Five-Year Plan Period,No.2018YFC1705405and The 66th China Postdoctoral Science Foundation,No.2019M660575.
文摘BACKGROUND Ulcerative colitis(UC)is an inflammatory bowel disease that is difficult to diagnose and treat.To date,the degree of inflammation in patients with UC has mainly been determined by measuring the levels of nonspecific indicators,such as C-reactive protein and the erythrocyte sedimentation rate,but these indicators have an unsatisfactory specificity.In this study,we performed bioinformatics analysis using data from the National Center for Biotechnology Information-Gene Expression Omnibus(NCBI-GEO)databases and verified the selected core genes in a mouse model of dextran sulfate sodium(DSS)-induced colitis.AIM To identify UC-related differentially expressed genes(DEGs)using a bioinformatics analysis and verify them in vivo and to identify novel biomarkers and the underlying mechanisms of UC.METHODS Two microarray datasets from the NCBI-GEO database were used,and DEGs between patients with UC and healthy controls were analyzed using GEO2R and Venn diagrams.We annotated these genes based on their functions and signaling pathways,and then protein-protein interactions(PPIs)were identified using the Search Tool for the Retrieval of Interacting Genes.The data were further analyzed with Cytoscape software and the Molecular Complex Detection(MCODE)app.The core genes were selected and a Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis was performed.Finally,colitis model mice were established by administering DSS,and the top three core genes were verified in colitis mice using real-time polymerase chain reaction(PCR).RESULTS One hundred and seventy-seven DEGs,118 upregulated and 59 downregulated,were initially identified from the GEO2R analysis and predominantly participated in inflammation-related pathways.Seven clusters with close interactions in UC formed:Seventeen core genes were upregulated[C-X-C motif chemokine ligand 13(CXCL13),C-X-C motif chemokine receptor 2(CXCR2),CXCL9,CXCL5,C-C motif chemokine ligand 18,interleukin 1 beta,matrix metallopeptidase 9,CXCL3,formyl peptide receptor 1,comple
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.
基金National Nature Science Foundation of China,Grant/Award Number:81102257Fundamental Research Funds for the Central Universities,Grant/Award Number:1012016Nanjing Science and Technology Development Plan,Grant/Award Number:201715021。
文摘Objective:To explore the modulation of mesenchymal stem cells(MSCs)on T helper 17(Th17)cells in systemic lupus erythematosus(SLE)and underlying mechanism.Methods:The concentration of matrix metalloproteinases(MMPs),CC chemokine ligand-2(CCL2),and interleukin-17(IL-17)in the serum of SLE patients and mice were detected by enzyme-linked immunosorbent assay.The expression of CCR2 and IL-17 of T lymphocytes were determined by flow cytometry.The effects of MSCs on Th17 cells were analyzed in lupus mice and coculture system in vitro.Results:The levels of MMPs,CCL2,IL-17,CCR2,and percentages of Th17 cells were significantly increased in SLE patients.These molecules and numbers of Th17 cells were downregulated by umbilical cord-derived MSCs(UC-MSCs)which relieve SLE disease.CCL2 neutralizing antibody blocked the effects of MSCs on Th17 cells.MMPs reversed the function of CCL2.Conclusion:The beneficial effects of MSCs on SLE patients rely on secreting MMPs,which reverse the activity of CCL2 to inhibit Th17 cells,suggesting the crucial MSCs–MMP–CCL2–CCR2–Th17–IL-17 pathway in SLE.
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.
