Macrophages represent a major cell type of innate immunity and have emerged as a critical player and therapeutic target in many chronic inflammatory diseases. Hepatic macrophages consist of Kupffer cells, which are or...Macrophages represent a major cell type of innate immunity and have emerged as a critical player and therapeutic target in many chronic inflammatory diseases. Hepatic macrophages consist of Kupffer cells, which are originated from the fetal yolk-sack, and infiltrated bone marrow-derived monocytes/macrophages. Hepatic macrophages play a central role in maintaining homeostasis of the liver and in the pathogenesis of liver injury, making them an attractive therapeutic target for liver diseases. However, the various populations of hepatic macrophages display different phenotypes and exert distinct functions. Thus, more research is required to better understand these cells to guide the development of macrophage-based therapeutic interventions. This review article will summarize the current knowledge on the origins and composition of hepatic macrophages, their functions in maintaining hepatic homeostasis, and their involvement in both promoting and resolving liver inflammation, injury, and fibrosis. Finally, the current strategies being developed to target hepatic macrophages for the treatment of liver diseases will be reviewed.展开更多
FTY720, an agonist for four of the five known sphingosine- 1-phosphate （SIP） receptors, has been reported to inhibit acute graft-versus-host disease （aGVHD）. Because FTY720 functions through multiple SIP receptors...FTY720, an agonist for four of the five known sphingosine- 1-phosphate （SIP） receptors, has been reported to inhibit acute graft-versus-host disease （aGVHD）. Because FTY720 functions through multiple SIP receptors, the mechanism of action through one or more of these receptors may account for its side effects. Thus, more selective SIP receptor modulators are needed to evaluate the roles of different S1P receptors and their therapeutic efficacies. In this study, we investigated the effect of an SIPl-selective agonist, CYM-5442, on the progression of aGVHD. We showed that CYM-5442 significantly inhibited but did not prevent aGVHD. CYM-5442 did not affect the infiltration of the donor T cells into the target organs, while the number of macrophages in GVHD organs was significantly reduced by CYM-5442 treatment. In vivo proliferation assays showed that the proliferation of macrophages was not suppressed by CYM-5442. Further studies using human endothelial cells demonstrated that CYM-5442 treatment downregulated CCL2 and CCL7 expression in endothelial cells, therefore reducing the migration of monocytes, from which tissue macrophages originate. Our data demonstrate the therapeutic efficacy of an SIPl-selective agonist in aGVHD and its possible mechanism of action. The results suggest that further investigations are needed regarding CYM-5442 as a potential therapeutic regimen for aGVHD.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
BACKGROUND Massive hepatocyte death is the core event in acute liver failure(ALF).Gasdermin D(GSDMD)-mediated pyroptosis is a type of highly inflammatory cell death.However,the role of hepatocyte pyroptosis and its me...BACKGROUND Massive hepatocyte death is the core event in acute liver failure(ALF).Gasdermin D(GSDMD)-mediated pyroptosis is a type of highly inflammatory cell death.However,the role of hepatocyte pyroptosis and its mechanisms of expanding inflammatory responses in ALF are unclear.AIM To investigate the role and mechanisms of GSDMD-mediated hepatocyte pyroptosis through in vitro and in vivo experiments.METHODS The expression of pyroptosis pathway-associated proteins in liver tissues from ALF patients and a hepatocyte injury model was examined by Western blot.GSDMD short hairpin RNA(shRNA)was used to investigate the effects of downregulation of GSDMD on monocyte chemotactic protein 1(MCP1)and its receptor CC chemokine receptor-2(CCR2)in vitro.For in vivo experiments,we used GSDMD knockout mice to investigate the role and mechanism of GSDMD in a D-galactose/lipopolysaccharide(D-Galn/LPS)-induced ALF mouse model.RESULTS The levels of pyroptosis pathway-associated proteins in liver tissue from ALF patients and a hepatocyte injury model increased significantly.The level of GSDMD-N protein increased most obviously(P<0.001).In vitro,downregulation of GSDMD by shRNA decreased the cell inhibition rate and the levels of MCP1/CCR2 proteins(P<0.01).In vivo,GSDMD knockout dramatically eliminated inflammatory damage in the liver and improved the survival of DGaln/LPS-induced ALF mice(P<0.001).Unlike the mechanism of immune cell pyroptosis that involves releasing interleukin(IL)-1βand IL-18,GSDMDmediated hepatocyte pyroptosis recruited macrophages via MCP1/CCR2 to aggravate hepatocyte death.However,this pathological process was inhibited after knocking down GSDMD.CONCLUSION GSDMD-mediated hepatocyte pyroptosis plays an important role in the pathogenesis of ALF,recruiting macrophages to release inflammatory mediators by upregulating MCP1/CCR2 and leading to expansion of the inflammatory responses.GSDMD knockout can reduce hepatocyte death and inflammatory responses,thus alleviating ALF.展开更多
Acute liver failure (ALF) is a devastating clinical syndrome characterised by progressive encephalopathy, coagulopathy, and circulatory dysfunction, which commonly leads to multiorgan failure and death. Central to the...Acute liver failure (ALF) is a devastating clinical syndrome characterised by progressive encephalopathy, coagulopathy, and circulatory dysfunction, which commonly leads to multiorgan failure and death. Central to the pathogenesis of ALF is activation of the immune system with mobilisation of cellular effectors and massive production of cytokines. As key components of the innate immune system, monocytes and macrophages are postulated to play a central role in the initiation, progression and resolution of ALF. ALF in humans follows a rapidly progressive clinical course that poses inherent difficulties in delineating the role of these pivotal immune cells. Therefore, a number of experimental models have been used to study the pathogenesis of ALF. Here we consider the evidence from experimental and human studies of ALF on the role of monocytes and macrophages in acute hepatic injury and the ensuing extrahepatic manifestations, including functional monocyte deactivation and multiple organ failure.展开更多
文摘Macrophages represent a major cell type of innate immunity and have emerged as a critical player and therapeutic target in many chronic inflammatory diseases. Hepatic macrophages consist of Kupffer cells, which are originated from the fetal yolk-sack, and infiltrated bone marrow-derived monocytes/macrophages. Hepatic macrophages play a central role in maintaining homeostasis of the liver and in the pathogenesis of liver injury, making them an attractive therapeutic target for liver diseases. However, the various populations of hepatic macrophages display different phenotypes and exert distinct functions. Thus, more research is required to better understand these cells to guide the development of macrophage-based therapeutic interventions. This review article will summarize the current knowledge on the origins and composition of hepatic macrophages, their functions in maintaining hepatic homeostasis, and their involvement in both promoting and resolving liver inflammation, injury, and fibrosis. Finally, the current strategies being developed to target hepatic macrophages for the treatment of liver diseases will be reviewed.
基金This work has been supported by the grants from the National Natural Science Foundation of China （91029703, 81072436 and 81273268）, with project funding from Suzhou City （SWG0904, SZS201109）, Priority Academic Program Development of Jiangsu Higher Education Institutions, Qing Lan Project of Jiangsu Province, Jiangsu Provincial Innovative Research Team and the Program for Changjiang Scholars and Innovative Research Team in University （IRT1075）.
文摘FTY720, an agonist for four of the five known sphingosine- 1-phosphate （SIP） receptors, has been reported to inhibit acute graft-versus-host disease （aGVHD）. Because FTY720 functions through multiple SIP receptors, the mechanism of action through one or more of these receptors may account for its side effects. Thus, more selective SIP receptor modulators are needed to evaluate the roles of different S1P receptors and their therapeutic efficacies. In this study, we investigated the effect of an SIPl-selective agonist, CYM-5442, on the progression of aGVHD. We showed that CYM-5442 significantly inhibited but did not prevent aGVHD. CYM-5442 did not affect the infiltration of the donor T cells into the target organs, while the number of macrophages in GVHD organs was significantly reduced by CYM-5442 treatment. In vivo proliferation assays showed that the proliferation of macrophages was not suppressed by CYM-5442. Further studies using human endothelial cells demonstrated that CYM-5442 treatment downregulated CCL2 and CCL7 expression in endothelial cells, therefore reducing the migration of monocytes, from which tissue macrophages originate. Our data demonstrate the therapeutic efficacy of an SIPl-selective agonist in aGVHD and its possible mechanism of action. The results suggest that further investigations are needed regarding CYM-5442 as a potential therapeutic regimen for aGVHD.
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 the National Natural Science Foundation of China,No.81570543 and No.81560104
文摘BACKGROUND Massive hepatocyte death is the core event in acute liver failure(ALF).Gasdermin D(GSDMD)-mediated pyroptosis is a type of highly inflammatory cell death.However,the role of hepatocyte pyroptosis and its mechanisms of expanding inflammatory responses in ALF are unclear.AIM To investigate the role and mechanisms of GSDMD-mediated hepatocyte pyroptosis through in vitro and in vivo experiments.METHODS The expression of pyroptosis pathway-associated proteins in liver tissues from ALF patients and a hepatocyte injury model was examined by Western blot.GSDMD short hairpin RNA(shRNA)was used to investigate the effects of downregulation of GSDMD on monocyte chemotactic protein 1(MCP1)and its receptor CC chemokine receptor-2(CCR2)in vitro.For in vivo experiments,we used GSDMD knockout mice to investigate the role and mechanism of GSDMD in a D-galactose/lipopolysaccharide(D-Galn/LPS)-induced ALF mouse model.RESULTS The levels of pyroptosis pathway-associated proteins in liver tissue from ALF patients and a hepatocyte injury model increased significantly.The level of GSDMD-N protein increased most obviously(P<0.001).In vitro,downregulation of GSDMD by shRNA decreased the cell inhibition rate and the levels of MCP1/CCR2 proteins(P<0.01).In vivo,GSDMD knockout dramatically eliminated inflammatory damage in the liver and improved the survival of DGaln/LPS-induced ALF mice(P<0.001).Unlike the mechanism of immune cell pyroptosis that involves releasing interleukin(IL)-1βand IL-18,GSDMDmediated hepatocyte pyroptosis recruited macrophages via MCP1/CCR2 to aggravate hepatocyte death.However,this pathological process was inhibited after knocking down GSDMD.CONCLUSION GSDMD-mediated hepatocyte pyroptosis plays an important role in the pathogenesis of ALF,recruiting macrophages to release inflammatory mediators by upregulating MCP1/CCR2 and leading to expansion of the inflammatory responses.GSDMD knockout can reduce hepatocyte death and inflammatory responses,thus alleviating ALF.
文摘Acute liver failure (ALF) is a devastating clinical syndrome characterised by progressive encephalopathy, coagulopathy, and circulatory dysfunction, which commonly leads to multiorgan failure and death. Central to the pathogenesis of ALF is activation of the immune system with mobilisation of cellular effectors and massive production of cytokines. As key components of the innate immune system, monocytes and macrophages are postulated to play a central role in the initiation, progression and resolution of ALF. ALF in humans follows a rapidly progressive clinical course that poses inherent difficulties in delineating the role of these pivotal immune cells. Therefore, a number of experimental models have been used to study the pathogenesis of ALF. Here we consider the evidence from experimental and human studies of ALF on the role of monocytes and macrophages in acute hepatic injury and the ensuing extrahepatic manifestations, including functional monocyte deactivation and multiple organ failure.
