Background Dendritic cells(DCs)are the most important antigen-presenting cells due to their professional and extremely efficient antigen-presenting function.The dynamics of cytoskeleton plays crucial regulated roles o...Background Dendritic cells(DCs)are the most important antigen-presenting cells due to their professional and extremely efficient antigen-presenting function.The dynamics of cytoskeleton plays crucial regulated roles on DCs’immune functions and biophysical properties.Several evidences show that tumor-derived suppressive cytokines deteriorate DCs’immune functions through remodeling their F-actin cytoskeleton.But the underlying mechanism is still elusive.Tropomodulin1(Tmod1),a cytoskeleton-binding protein,regulates and stabilizes actin filaments lengths and cytoskeleton architecture,which involves in the regulations of the morphology,formation of neural dendrites and biophysical properties of cells.Our previous studies found that mature DCs(mDCs)had a higher expression of Tmod1 than immature DCs(imDCs). Therefore,it’s hypothesized that Tmod1 maybe involve in the modification of DCs’functions.Objective The aim of the study is to investigate the effects of Tmodl on the immune functions and biophysical properties of DCs and the underlying mechanisms in order to further understand the biological behaviors of DCs.Methods Bone marrow-derived cells were harvested from wild type(C57BL/6 J)mice and Tmod1 knockout mice(Tmod1 overexpressing transgenic(TOT)/Tmod1-/-)and differentiated to immature dendritic cells(imDCs)by rmGM-CSF and rmIL-4.imDCs were then matured by lipopolysaccharides(LPS)treatment.The expressions of the surface markers in DCs,including CD80,CD86,CD40,MHC-Ⅱand CCR7,were detected by flow cytometry,Western blot and qRT-PCR.The inflammation cytokines such as IL-6,IFN-γ,IFN-βand IL-10 were also detected by flow cytometry.The immune functions and the biophysical properties of DCs were compared between the wild type and Tmod1 knockout mice.The F-actin content and dendritic pseudopodia of these two kinds of DCs were detected by flow cytometry and laser scanning confocal microscope respectively.Finally,we detected the MyD88 dependent and independent signaling pathway to discover the molecular mechanisms.Results We found that Tmod1-deficient mDCs showed deficient antigen-presenting ability and they failed to express enough MHC-Ⅱ,co-stimulated molecules(CD80/86,CD40)and CCR7 on their cell surface.The secretions of the inflammatory cytokines IL-6 and IFN-γwere decreased while the anti-inflammatory cytokines IFN-βand IL-10 were increased in the supernatant of Tmod1-deficient mDCs.As compared to DCs of wild type mice,the migration ability of DCs from Tmod1 knockout mice were dramatically damaged including their free migration and CCL19 mediated chemotaxis migration.However,we found that Tmod1 knockout had no effects on the imDCs’endocytosis ability.Furthermore,Tmod1 knockout DCs showed higher osmotic fragility,lower Young’s modulus,less F-actin content and shorter dendritic pseudopodia.Under LPS stimulation,the phosphorylation level of p65 and p38 were significantly downregulated in Tmod1 knockout mice while the expression of p-IRF3 was upregulated.Conclusions These results indicated that Tmodl knockout leads to deficient antigen-presenting ability and impaired migration of DCs as well as their biophysical properties.The underlying mechanisms are due to the inhibitions of the TLR4-mediated NF-κB and p38 MAPK singling pathway and the activation of the IRF3 signaling pathway,as well as the disturbed reorganization of the F-actin cytoskeleton.Our results provide a new insight on the functions of Tmod1 which can affect the DCs’immune functions and biophysical properties through regulating the TLR4-mediated singling pathways and cytoskeleton remodeling.展开更多
Implant materials,as foreign objects to host,can cause various degrees of inflammation in most cases.The inflammation is triggered by a series of immune responses and directly impacts the tissue regeneration process,w...Implant materials,as foreign objects to host,can cause various degrees of inflammation in most cases.The inflammation is triggered by a series of immune responses and directly impacts the tissue regeneration process,which determines the outcome of tissue repair.The immune responses are complex process involving numerous immune cells and can be divide into innate immune and adaptive immune responses.Once materials are implanted,innate immune responses are activated under the mediation of several immune cells(e.g.neutrophils and macrophages),meanwhile immature dendritic cells(imDCs)are recruited to the implant sites to recognize,internalize and process antigens.Upon antigen uptake,imDCs gradually differentiate into mature dendritic cells(mDCs)and migrate to secondary lymph nodes.In the lymph nodes,mDCs present processed antigen peptides to naive T lymphocytes and activate their antigen specific proliferation,resulting in initiation of adaptive immune responses.Due to their key position in the immune system,serving to bridge innate and adaptive immunity,DCs are crucial to guiding and modulating the immune responses caused by implanted materials.Therefore,figuring out the response of DCs to implanted materials and the exact role of DCs in tissue healing processes will provide deeper insight for the rational design of biomaterials.Previous studies on the effects of implants on immune functions of DCs are mainly focused on physical and chemical properties of the materials(e.g.released chemical composition,surface chemistry,substrate stiffness and surface topography).All these factors will change the microenvironment of the tissue around implant materials,which affect the immune functions of DCs.However,the change of microenvironment not only directly derives from the physical and chemical properties of the material(intrinsic),but also indirectly results from the remodeled extracellular matrix(ECM)caused by implanted materials.When blood or tissue fluid contact with materials after implantation,proteins(e.g.fibrin and collagen)will absorb and deposit on the surface of implants,leading to a provisionally stable matrix with microporous fibrous-liked network structure.It means that the remodeled ECM can provide adhesion sites for recruited DCs and form spatial confinement.DCs,as a kind of cells that are extremely sensitive to mechanical stimuli,theoretically,can response to the mechanical stimuli coming from spatial confinement of remodeled ECM,which may lead to a series of modulations in their cell morphologies and immune functions.Then,the remodeled ECM is a non-negligible mechanical cue.However,to the best of our knowledge,there is a lack of a simple and effective model to establish the relationship between the immune functions of DCs and remodeled ECM.Most studies on the responses of DCs to implanted materials are still based on suspension culture model,which is the normal status of DCs in vitro culture systems.In addition,the processes by which DC exerts immune functions(both endocytosis and antigen presentation)are dynamically physical interaction.It means that the changes of DCs’immune functions are highly correlated with the changes of their biomechanical characteristics caused by remodeled ECM.In this work,we have found that the ECM was remodeled by a large amount of fibrin matrix deposited on the surface of implants in the early stage of the inflammations following implantation.Thus,we used non-toxic salmon fibrin hydrogels with microporous fibrous-liked network structure to mimic the deposited fibrin matrix.Then,human monocyte-derived DCs were cultured on the surface and inside of the fibrin hydrogels to mimic the different spatial confinement states of fibrin matrix.Our results indicated that cell morphologies and cytoskeleton structures of DCs were regulated by the spatial confinement of fibrin hydrogels,resulting in generating mechanical stimuli for DCs.Furthermore,we have found that the biomechanical characteristics and the immune functions of both imDCs and mDC were also modulated.Considering the changes in surface markers,secreted cytokines and biomechanical characteristics of DCs,it indicates that the tendency and magnitude of modulations were highly associated with the spatial confinement of fibrin hydrogels.This model demonstrated that mechanical stimuli deriving from spatial confinement of deposited fibrin matrix is an important factor for regulating the biomechanical characteristics and immune functions of DCs.展开更多
目的锌指蛋白335(Zfp335)参与调控胸腺T细胞的早期发育和外周T细胞亚群的分化,本研究旨在探讨Zfp335调控调节性T细胞(Treg)在肿瘤免疫中的作用和机制。方法用他莫昔芬在Treg中特异性敲除Zfp335基因[Zfp335^(fl/fl)叉头盒P3(FOXP3)creERT...目的锌指蛋白335(Zfp335)参与调控胸腺T细胞的早期发育和外周T细胞亚群的分化,本研究旨在探讨Zfp335调控调节性T细胞(Treg)在肿瘤免疫中的作用和机制。方法用他莫昔芬在Treg中特异性敲除Zfp335基因[Zfp335^(fl/fl)叉头盒P3(FOXP3)creERT2],并构建MC38移植瘤模型。接种肿瘤后第7天,观察并测量肿瘤的大小,第12天剥离肿瘤组织,用流式细胞术检测野生型(WT)组和Zfp335敲除(Zfp335^(CKO))组小鼠肿瘤浸润淋巴细胞中CD4^(+)T细胞、CD8^(+)T细胞和Treg的比例,以及效应性Treg(eTreg)的线粒体功能。结果自接种肿瘤后第10天开始,Zfp335^(CKO)组肿瘤体积显著小于WT组。Zfp335^(CKO)组CD4^(+)T细胞和CD8^(+)T细胞的肿瘤浸润比例、及其对应的效应细胞比例显著高于WT组。Zfp335^(CKO)组CD4^(+)T细胞和CD8^(+)T细胞分泌细胞因子γ干扰素(IFN-γ)、肿瘤坏死因子α(TNF-α)的比例显著高于WT组,Zfp335^(CKO)组CD8^(+)T细胞分泌颗粒酶B(GzmB)的比例显著高于WT组。Zfp335^(CKO)组Treg、诱导性共刺激分子(ICOS)+Treg比例显著低于WT组。Zfp335^(CKO)组eTreg表达Mitotracker Deep Red的水平显著低于WT组。结论在肿瘤发生过程中,Treg特异性缺失Zfp335导致其活化减弱,与eTreg的线粒体功能降低有关;Zfp335^(CKO)小鼠肿瘤浸润的效应性T细胞增多、分泌杀伤性细胞因子增多,进而抵抗肿瘤发展。展开更多
基金funded by the National Natural Science Foundation of China ( 31660258,31771014, 31860262,31570938,31260227)the Science and Technology Foundation of Guizhou Province ( 2019-2787,2018-1412, 2016-5676,2017-5718)+2 种基金the Science and Technology Innovative Talent Team of Guizhou Province ( 2015-4021)the 2011 Collaborative Innovation Program of Guizhou Province ( 2015-04 )the Cell and Gene Engineering Innovative Research Groups of Guizhou Province ( KY-2016-031)
文摘Background Dendritic cells(DCs)are the most important antigen-presenting cells due to their professional and extremely efficient antigen-presenting function.The dynamics of cytoskeleton plays crucial regulated roles on DCs’immune functions and biophysical properties.Several evidences show that tumor-derived suppressive cytokines deteriorate DCs’immune functions through remodeling their F-actin cytoskeleton.But the underlying mechanism is still elusive.Tropomodulin1(Tmod1),a cytoskeleton-binding protein,regulates and stabilizes actin filaments lengths and cytoskeleton architecture,which involves in the regulations of the morphology,formation of neural dendrites and biophysical properties of cells.Our previous studies found that mature DCs(mDCs)had a higher expression of Tmod1 than immature DCs(imDCs). Therefore,it’s hypothesized that Tmod1 maybe involve in the modification of DCs’functions.Objective The aim of the study is to investigate the effects of Tmodl on the immune functions and biophysical properties of DCs and the underlying mechanisms in order to further understand the biological behaviors of DCs.Methods Bone marrow-derived cells were harvested from wild type(C57BL/6 J)mice and Tmod1 knockout mice(Tmod1 overexpressing transgenic(TOT)/Tmod1-/-)and differentiated to immature dendritic cells(imDCs)by rmGM-CSF and rmIL-4.imDCs were then matured by lipopolysaccharides(LPS)treatment.The expressions of the surface markers in DCs,including CD80,CD86,CD40,MHC-Ⅱand CCR7,were detected by flow cytometry,Western blot and qRT-PCR.The inflammation cytokines such as IL-6,IFN-γ,IFN-βand IL-10 were also detected by flow cytometry.The immune functions and the biophysical properties of DCs were compared between the wild type and Tmod1 knockout mice.The F-actin content and dendritic pseudopodia of these two kinds of DCs were detected by flow cytometry and laser scanning confocal microscope respectively.Finally,we detected the MyD88 dependent and independent signaling pathway to discover the molecular mechanisms.Results We found that Tmod1-deficient mDCs showed deficient antigen-presenting ability and they failed to express enough MHC-Ⅱ,co-stimulated molecules(CD80/86,CD40)and CCR7 on their cell surface.The secretions of the inflammatory cytokines IL-6 and IFN-γwere decreased while the anti-inflammatory cytokines IFN-βand IL-10 were increased in the supernatant of Tmod1-deficient mDCs.As compared to DCs of wild type mice,the migration ability of DCs from Tmod1 knockout mice were dramatically damaged including their free migration and CCL19 mediated chemotaxis migration.However,we found that Tmod1 knockout had no effects on the imDCs’endocytosis ability.Furthermore,Tmod1 knockout DCs showed higher osmotic fragility,lower Young’s modulus,less F-actin content and shorter dendritic pseudopodia.Under LPS stimulation,the phosphorylation level of p65 and p38 were significantly downregulated in Tmod1 knockout mice while the expression of p-IRF3 was upregulated.Conclusions These results indicated that Tmodl knockout leads to deficient antigen-presenting ability and impaired migration of DCs as well as their biophysical properties.The underlying mechanisms are due to the inhibitions of the TLR4-mediated NF-κB and p38 MAPK singling pathway and the activation of the IRF3 signaling pathway,as well as the disturbed reorganization of the F-actin cytoskeleton.Our results provide a new insight on the functions of Tmod1 which can affect the DCs’immune functions and biophysical properties through regulating the TLR4-mediated singling pathways and cytoskeleton remodeling.
基金funded by grants from the National Natural Science Foundation of China ( 31771014, 11762006,31660258,31860262,11762006,81460254 )the 2011 Collaborative Innovation Program of Guizhou Province ( 2015-04)+1 种基金the Science and Technology Innovative Talent Team of Guizhou Province ( 2015-4021)the Science and Technology Foundation of Guizhou Province ( 2018-1412,2016-5676,2017-5718)
文摘Implant materials,as foreign objects to host,can cause various degrees of inflammation in most cases.The inflammation is triggered by a series of immune responses and directly impacts the tissue regeneration process,which determines the outcome of tissue repair.The immune responses are complex process involving numerous immune cells and can be divide into innate immune and adaptive immune responses.Once materials are implanted,innate immune responses are activated under the mediation of several immune cells(e.g.neutrophils and macrophages),meanwhile immature dendritic cells(imDCs)are recruited to the implant sites to recognize,internalize and process antigens.Upon antigen uptake,imDCs gradually differentiate into mature dendritic cells(mDCs)and migrate to secondary lymph nodes.In the lymph nodes,mDCs present processed antigen peptides to naive T lymphocytes and activate their antigen specific proliferation,resulting in initiation of adaptive immune responses.Due to their key position in the immune system,serving to bridge innate and adaptive immunity,DCs are crucial to guiding and modulating the immune responses caused by implanted materials.Therefore,figuring out the response of DCs to implanted materials and the exact role of DCs in tissue healing processes will provide deeper insight for the rational design of biomaterials.Previous studies on the effects of implants on immune functions of DCs are mainly focused on physical and chemical properties of the materials(e.g.released chemical composition,surface chemistry,substrate stiffness and surface topography).All these factors will change the microenvironment of the tissue around implant materials,which affect the immune functions of DCs.However,the change of microenvironment not only directly derives from the physical and chemical properties of the material(intrinsic),but also indirectly results from the remodeled extracellular matrix(ECM)caused by implanted materials.When blood or tissue fluid contact with materials after implantation,proteins(e.g.fibrin and collagen)will absorb and deposit on the surface of implants,leading to a provisionally stable matrix with microporous fibrous-liked network structure.It means that the remodeled ECM can provide adhesion sites for recruited DCs and form spatial confinement.DCs,as a kind of cells that are extremely sensitive to mechanical stimuli,theoretically,can response to the mechanical stimuli coming from spatial confinement of remodeled ECM,which may lead to a series of modulations in their cell morphologies and immune functions.Then,the remodeled ECM is a non-negligible mechanical cue.However,to the best of our knowledge,there is a lack of a simple and effective model to establish the relationship between the immune functions of DCs and remodeled ECM.Most studies on the responses of DCs to implanted materials are still based on suspension culture model,which is the normal status of DCs in vitro culture systems.In addition,the processes by which DC exerts immune functions(both endocytosis and antigen presentation)are dynamically physical interaction.It means that the changes of DCs’immune functions are highly correlated with the changes of their biomechanical characteristics caused by remodeled ECM.In this work,we have found that the ECM was remodeled by a large amount of fibrin matrix deposited on the surface of implants in the early stage of the inflammations following implantation.Thus,we used non-toxic salmon fibrin hydrogels with microporous fibrous-liked network structure to mimic the deposited fibrin matrix.Then,human monocyte-derived DCs were cultured on the surface and inside of the fibrin hydrogels to mimic the different spatial confinement states of fibrin matrix.Our results indicated that cell morphologies and cytoskeleton structures of DCs were regulated by the spatial confinement of fibrin hydrogels,resulting in generating mechanical stimuli for DCs.Furthermore,we have found that the biomechanical characteristics and the immune functions of both imDCs and mDC were also modulated.Considering the changes in surface markers,secreted cytokines and biomechanical characteristics of DCs,it indicates that the tendency and magnitude of modulations were highly associated with the spatial confinement of fibrin hydrogels.This model demonstrated that mechanical stimuli deriving from spatial confinement of deposited fibrin matrix is an important factor for regulating the biomechanical characteristics and immune functions of DCs.
文摘目的锌指蛋白335(Zfp335)参与调控胸腺T细胞的早期发育和外周T细胞亚群的分化,本研究旨在探讨Zfp335调控调节性T细胞(Treg)在肿瘤免疫中的作用和机制。方法用他莫昔芬在Treg中特异性敲除Zfp335基因[Zfp335^(fl/fl)叉头盒P3(FOXP3)creERT2],并构建MC38移植瘤模型。接种肿瘤后第7天,观察并测量肿瘤的大小,第12天剥离肿瘤组织,用流式细胞术检测野生型(WT)组和Zfp335敲除(Zfp335^(CKO))组小鼠肿瘤浸润淋巴细胞中CD4^(+)T细胞、CD8^(+)T细胞和Treg的比例,以及效应性Treg(eTreg)的线粒体功能。结果自接种肿瘤后第10天开始,Zfp335^(CKO)组肿瘤体积显著小于WT组。Zfp335^(CKO)组CD4^(+)T细胞和CD8^(+)T细胞的肿瘤浸润比例、及其对应的效应细胞比例显著高于WT组。Zfp335^(CKO)组CD4^(+)T细胞和CD8^(+)T细胞分泌细胞因子γ干扰素(IFN-γ)、肿瘤坏死因子α(TNF-α)的比例显著高于WT组,Zfp335^(CKO)组CD8^(+)T细胞分泌颗粒酶B(GzmB)的比例显著高于WT组。Zfp335^(CKO)组Treg、诱导性共刺激分子(ICOS)+Treg比例显著低于WT组。Zfp335^(CKO)组eTreg表达Mitotracker Deep Red的水平显著低于WT组。结论在肿瘤发生过程中,Treg特异性缺失Zfp335导致其活化减弱,与eTreg的线粒体功能降低有关;Zfp335^(CKO)小鼠肿瘤浸润的效应性T细胞增多、分泌杀伤性细胞因子增多,进而抵抗肿瘤发展。
