Exhausted CD8^(+)T(Tex)cells are dysfunctional due to persistent antigen exposure in chronic viral infection and tumor contexts.A stem cell-like Tex(Tex-stem)subset can self-renew and differentiate into terminally exh...Exhausted CD8^(+)T(Tex)cells are dysfunctional due to persistent antigen exposure in chronic viral infection and tumor contexts.A stem cell-like Tex(Tex-stem)subset can self-renew and differentiate into terminally exhausted(Tex-term)cells.Here,we show that ectopic Tcf1 expression potently promoted the generation of Tex-stem cells in both a chronic viral infection and preclinical tumor models.Tcf1 overexpression diminished coinhibitory receptor expression and enhanced polycytokine-producing capacity while retaining a heightened responses to checkpoint blockade,leading to enhanced viral and tumor control.Mechanistically,ectopically expressed Tcf1 exploited existing and novel chromatin accessible sites as transcriptional enhancers or repressors and modulated the transcriptome by enforcing pre-existing expression patterns in Tex-stem cells,such as enhanced suppression of Blimp1 and Bim and acquisition of new downstream genes,including Mx1,Tox2,and Runx3.These findings reveal a pronounced impact of ectopic Tcf1 expression on Tex functional restoration and highlight the therapeutic potential of harnessing Tcf1-enforced transcriptional programs.展开更多
Transcription factors and DNA/histone modification enzymes work in concert to establish and maintain cell identity. CD4^＋ and CD8^＋ T cells are key players in cellular immunity with distinct functions. Recent studie...Transcription factors and DNA/histone modification enzymes work in concert to establish and maintain cell identity. CD4^＋ and CD8^＋ T cells are key players in cellular immunity with distinct functions. Recent studies offer novel insights into how their identities are established in the thymus and maintained in the periphery during immune responses. During thymic maturation, Thpok, HDAC1 and HDAC2 guard CD4^＋ T cells from activation of CD8^＋ cytotoxic genes, and Tcfl and Left utilize their intrinsic HDAC activity to shut down CD4^＋ lineage-associated genes in CD8^＋ T cells. In activated CD4＋ T cells, Tcfl and Left act upstream of the Bc16-Blimpl axis to direct differentiation of follicular helper T （Tfh） cells, and prevent diversion of Tfh to IL-17-producing cells. In parallel, T-bet, together with Eomes or Blimpl, ensures proper induction of the cytotoxic program in CD8^＋ effectors elicited by acute infection, and prevents generation of pathogenic, IL-17-producing CD8^＋ effector T cells. Antigen persistence due to chronic viral infection leads to CD8^＋ T cell exhaustion. A portion of exhausted CD8^＋ T cells has the capacity to activate the Tfh program in a Tcfl-dependent manner. Those Tfh-like CD8^＋ T cells exhibit enhanced proliferative capacity in response to PD-1 blockage therapy and are more effective in curtailing viral replication. Thus, dissecting the molecular aspects of T cell identity, during development and immune responses, may lead to new therapies for treating autoimmunity, tumors, and persistent infections.展开更多
An important factor in the emergence and progre sion of osteosarcoma(OS)is the dysregulated expression of microRNAs(miRNAs).Transcription factor 7-like 1(TCF7LI),a member of the T cell factor/lymphoid enhancer factor(...An important factor in the emergence and progre sion of osteosarcoma(OS)is the dysregulated expression of microRNAs(miRNAs).Transcription factor 7-like 1(TCF7LI),a member of the T cell factor/lymphoid enhancer factor(TCF/LEF)transcription factor family,interacts with the Wnt signaling pathway regulator β-catenin and acts as a DNA-specific binding protein.This study sought to elucidate the impact of the interaction between miR 3293p and TCF7L1 on.the growth and apoptosis of OS and analyze the regulatory expression relationship between miRNA and mRNA in osteosarcoma cells using a variety of approaches.MiR329-3p was significantly downregulated,while TCF7L1 was considerably up-regulated in all examined OS cell lines.Additionally,a clinical comparison study was performed using the TCGA database.Subsequently,the regulatory relationship between miR-329-3p and TCF7L1 on the proliferation and apoptosis of OS cells was verified through in vitro and in vivo experiments.When miR 329-3p was transfected into the OS cell line,the expression of TCF7L1 decreased,the proliferation of OS cells was inhibited,the cytoskeleton disintegrated,and the nucleus condensed to fom apoptotic bodies.The expression of proteins that indicate apoptosis increased simultaneously.The cell cycle was arrested in the G0/G1 phase,and the G1/S transition was blocked.The introduction of miR 3293p also inhibited downstream Cyclin D1 of the Wnt pathway.Xenograf experiments indicated that the overexpression of miR-329-3p signi ficanly inhibited the growth of OS xenografts in nude mice,and the expression of TCF7L1 and C-Myc in tumor tssues decreased.MiR 329-3p was significantly reduced in OS cells and played a suppressive role in tumorigenesis and proliferation by targeting TCF7L1 both in vitro and in vivo.Osteosarcoma cell cycle arrest and pathway inhibition were observed upon the regulation of TCF7LI by miR 3293p.Summarizing these results,it can be inferred that miR.3293p exerts anticancer efects in osteosarcoma by inhibiting TCF7L1.展开更多
LEF1/TCFs are high mobility group box-containing transcriptional factors mediating canonical Wnt/β-catenin signaling during early embryogenesis and tumorigenesis. β-Catenin forms a complex with LEF 1/TCFs and transa...LEF1/TCFs are high mobility group box-containing transcriptional factors mediating canonical Wnt/β-catenin signaling during early embryogenesis and tumorigenesis. β-Catenin forms a complex with LEF 1/TCFs and transactivates LEF1/TCF-mediated transcriptions during dorsalization. Although LEF-mediated transcription is also implicated in ventralization, the underlying molecular mechanism is not well understood. Using the vertebrate Xenopus laevis model system, we found that Xom, which is a ventralizing homeobox protein with dual roles of transcriptional activation and repression, forms a complex with LEF 1/TCF through its homeodomain and transactivates LEF 1/TCF-mediated transcription through its N-terminal transactivation domain （TAD）. Our data show that Xom lacking the N-terminal TAD fails to transactivate ventral genes, such as BMP4 and Xom itself, but retains the ability to suppress transcriptional activation of dorsal gene promoters, such as the Goosecoid promoter, indicating that transactivation and repression are separable functions of Xom. It has been postulated that Xom forms a positive re-enforcement loop with BMP4 to promote ventral- ization and to suppress dorsal gene expression. Consistent with an essential role of Xom transactivation of LEF1/TCFs during early embryogenesis, we found that expression of the dominant-negative Xom mutant that lacks the TAD fails to re-enforce the ventral signaling of BMP4 and causes a catastrophic effect during gastrulation. Our data suggest that the functional interaction of Xom and LEF 1/TCF-factors is essential for ventral cell fate determination and that LEF 1/TCF factors may function as a point of convergence to mediate the combined signaling of Wnt/β-catenin and BMP4/Xom pathways during early embryogenesis.展开更多
Blockade of programmed death-1(PD-1)reinvigorates exhausted CD8^(+)T cells,resulting in tumor regression in cancer patients.Recently,reinvigoration of exhausted CD8^(+)T cells following PD-1 blockade was shown to be C...Blockade of programmed death-1(PD-1)reinvigorates exhausted CD8^(+)T cells,resulting in tumor regression in cancer patients.Recently,reinvigoration of exhausted CD8^(+)T cells following PD-1 blockade was shown to be CD28-dependent in mouse models.Herein,we examined the role of CD28 in anti-PD-1 antibody-induced human T cell reinvigoration using tumor-infiltrating CD8^(+)T cells(CD8^(+)TILs)obtained from non-small-cell lung cancer patients.Single-cell analysis demonstrated a distinct expression pattern of CD28 between mouse and human CD8^(+)TILs.Furthermore,we found that human CD28^(+)CD8^(+)but not CD28^(–)CD8^(+)TILs responded to PD-1 blockade irrespective of B7/CD28 blockade,indicating that CD28 costimulation in human CD8^(+)TILs is dispensable for PD-1 blockade-induced reinvigoration and that loss of CD28 expression serves as a marker of anti-PD-1 antibody-unresponsive CD8^(+)TILs.Transcriptionally and phenotypically,PD-1 blockade-unresponsive human CD28^(–)PD-1^(+)CD8^(+)TILs exhibited characteristics of terminally exhausted CD8^(+)T cells with low TCF1 expression.Notably,CD28^(–)PD-1^(+)CD8^(+)TILs had preserved machinery to respond to IL-15,and IL-15 treatment enhanced the proliferation of CD28^(–)PD-1^(+)CD8^(+)TILs as well as CD28^(+)PD-1^(+)CD8^(+)TILs.Taken together,these results show that loss of CD28 expression is a marker of PD-1 blockade-unresponsive human CD8^(+)TILs with a TCF1–signature and provide mechanistic insights into combining IL-15 with anti-PD-1 antibodies.展开更多
Type 1 diabetes mellitus(T1D)is a chronic autoimmune condition in which the immune system destroys insulin-producing pancreatic β cells.In addition to well-established pathogenic effector T cells,regulatory T cells(T...Type 1 diabetes mellitus(T1D)is a chronic autoimmune condition in which the immune system destroys insulin-producing pancreatic β cells.In addition to well-established pathogenic effector T cells,regulatory T cells(Tregs)have also been shown to be defective in T1D.Thus,an increasing number of therapeutic approaches are being developed to target Tregs.However,the role and mechanisms of TGF-β-induced Tregs(iTregs)in T1D remain poorly understood.Here,using a streptozotocin(STZ)-induced preclinical T1D mouse model,we found that iTregs could ameliorate the development of T1D and preserve β cell function.The preventive effect was associated with the inhibition of type 1 cytotoxic T(Tel)cell function and rebalancing the Treg/Tc1 cell ratio in recipients.Furthermore,we showed that the underlying mechanisms were due to the TGF-β-mediated combinatorial actions of mTOR and TCF1.In addition to the preventive role,the therapeutic effects of iTregs on the established STZ-T1D and nonobese diabetic(NOD)mouse models were tested,which revealed improved β cell function.Our findings therefore provide key new insights into the basic mechanisms involved in the therapeutic role of iTregs in T1D.展开更多
基金supported by grants from the NIH(AI112579,AI121080 and AI139874 to H.-H.X.,GM133712 to C.Z.,and GM113961,AI147064 and AI114543 to V.P.B.)the Veteran Affairs BLR&D Merit Review Program(BX002903)to H.-H.X.
文摘Exhausted CD8^(+)T(Tex)cells are dysfunctional due to persistent antigen exposure in chronic viral infection and tumor contexts.A stem cell-like Tex(Tex-stem)subset can self-renew and differentiate into terminally exhausted(Tex-term)cells.Here,we show that ectopic Tcf1 expression potently promoted the generation of Tex-stem cells in both a chronic viral infection and preclinical tumor models.Tcf1 overexpression diminished coinhibitory receptor expression and enhanced polycytokine-producing capacity while retaining a heightened responses to checkpoint blockade,leading to enhanced viral and tumor control.Mechanistically,ectopically expressed Tcf1 exploited existing and novel chromatin accessible sites as transcriptional enhancers or repressors and modulated the transcriptome by enforcing pre-existing expression patterns in Tex-stem cells,such as enhanced suppression of Blimp1 and Bim and acquisition of new downstream genes,including Mx1,Tox2,and Runx3.These findings reveal a pronounced impact of ectopic Tcf1 expression on Tex functional restoration and highlight the therapeutic potential of harnessing Tcf1-enforced transcriptional programs.
文摘Transcription factors and DNA/histone modification enzymes work in concert to establish and maintain cell identity. CD4^＋ and CD8^＋ T cells are key players in cellular immunity with distinct functions. Recent studies offer novel insights into how their identities are established in the thymus and maintained in the periphery during immune responses. During thymic maturation, Thpok, HDAC1 and HDAC2 guard CD4^＋ T cells from activation of CD8^＋ cytotoxic genes, and Tcfl and Left utilize their intrinsic HDAC activity to shut down CD4^＋ lineage-associated genes in CD8^＋ T cells. In activated CD4＋ T cells, Tcfl and Left act upstream of the Bc16-Blimpl axis to direct differentiation of follicular helper T （Tfh） cells, and prevent diversion of Tfh to IL-17-producing cells. In parallel, T-bet, together with Eomes or Blimpl, ensures proper induction of the cytotoxic program in CD8^＋ effectors elicited by acute infection, and prevents generation of pathogenic, IL-17-producing CD8^＋ effector T cells. Antigen persistence due to chronic viral infection leads to CD8^＋ T cell exhaustion. A portion of exhausted CD8^＋ T cells has the capacity to activate the Tfh program in a Tcfl-dependent manner. Those Tfh-like CD8^＋ T cells exhibit enhanced proliferative capacity in response to PD-1 blockage therapy and are more effective in curtailing viral replication. Thus, dissecting the molecular aspects of T cell identity, during development and immune responses, may lead to new therapies for treating autoimmunity, tumors, and persistent infections.
基金The Fund of National Cancer Center Research and Development(26-A-4),The Grants-in-Aid for Scientific Research(Grant Nos.15K10451,16K10866 and 16K20063)from Japan Society for the Promotion of Science.
文摘An important factor in the emergence and progre sion of osteosarcoma(OS)is the dysregulated expression of microRNAs(miRNAs).Transcription factor 7-like 1(TCF7LI),a member of the T cell factor/lymphoid enhancer factor(TCF/LEF)transcription factor family,interacts with the Wnt signaling pathway regulator β-catenin and acts as a DNA-specific binding protein.This study sought to elucidate the impact of the interaction between miR 3293p and TCF7L1 on.the growth and apoptosis of OS and analyze the regulatory expression relationship between miRNA and mRNA in osteosarcoma cells using a variety of approaches.MiR329-3p was significantly downregulated,while TCF7L1 was considerably up-regulated in all examined OS cell lines.Additionally,a clinical comparison study was performed using the TCGA database.Subsequently,the regulatory relationship between miR-329-3p and TCF7L1 on the proliferation and apoptosis of OS cells was verified through in vitro and in vivo experiments.When miR 329-3p was transfected into the OS cell line,the expression of TCF7L1 decreased,the proliferation of OS cells was inhibited,the cytoskeleton disintegrated,and the nucleus condensed to fom apoptotic bodies.The expression of proteins that indicate apoptosis increased simultaneously.The cell cycle was arrested in the G0/G1 phase,and the G1/S transition was blocked.The introduction of miR 3293p also inhibited downstream Cyclin D1 of the Wnt pathway.Xenograf experiments indicated that the overexpression of miR-329-3p signi ficanly inhibited the growth of OS xenografts in nude mice,and the expression of TCF7L1 and C-Myc in tumor tssues decreased.MiR 329-3p was significantly reduced in OS cells and played a suppressive role in tumorigenesis and proliferation by targeting TCF7L1 both in vitro and in vivo.Osteosarcoma cell cycle arrest and pathway inhibition were observed upon the regulation of TCF7LI by miR 3293p.Summarizing these results,it can be inferred that miR.3293p exerts anticancer efects in osteosarcoma by inhibiting TCF7L1.
文摘LEF1/TCFs are high mobility group box-containing transcriptional factors mediating canonical Wnt/β-catenin signaling during early embryogenesis and tumorigenesis. β-Catenin forms a complex with LEF 1/TCFs and transactivates LEF1/TCF-mediated transcriptions during dorsalization. Although LEF-mediated transcription is also implicated in ventralization, the underlying molecular mechanism is not well understood. Using the vertebrate Xenopus laevis model system, we found that Xom, which is a ventralizing homeobox protein with dual roles of transcriptional activation and repression, forms a complex with LEF 1/TCF through its homeodomain and transactivates LEF 1/TCF-mediated transcription through its N-terminal transactivation domain （TAD）. Our data show that Xom lacking the N-terminal TAD fails to transactivate ventral genes, such as BMP4 and Xom itself, but retains the ability to suppress transcriptional activation of dorsal gene promoters, such as the Goosecoid promoter, indicating that transactivation and repression are separable functions of Xom. It has been postulated that Xom forms a positive re-enforcement loop with BMP4 to promote ventral- ization and to suppress dorsal gene expression. Consistent with an essential role of Xom transactivation of LEF1/TCFs during early embryogenesis, we found that expression of the dominant-negative Xom mutant that lacks the TAD fails to re-enforce the ventral signaling of BMP4 and causes a catastrophic effect during gastrulation. Our data suggest that the functional interaction of Xom and LEF 1/TCF-factors is essential for ventral cell fate determination and that LEF 1/TCF factors may function as a point of convergence to mediate the combined signaling of Wnt/β-catenin and BMP4/Xom pathways during early embryogenesis.
文摘Blockade of programmed death-1(PD-1)reinvigorates exhausted CD8^(+)T cells,resulting in tumor regression in cancer patients.Recently,reinvigoration of exhausted CD8^(+)T cells following PD-1 blockade was shown to be CD28-dependent in mouse models.Herein,we examined the role of CD28 in anti-PD-1 antibody-induced human T cell reinvigoration using tumor-infiltrating CD8^(+)T cells(CD8^(+)TILs)obtained from non-small-cell lung cancer patients.Single-cell analysis demonstrated a distinct expression pattern of CD28 between mouse and human CD8^(+)TILs.Furthermore,we found that human CD28^(+)CD8^(+)but not CD28^(–)CD8^(+)TILs responded to PD-1 blockade irrespective of B7/CD28 blockade,indicating that CD28 costimulation in human CD8^(+)TILs is dispensable for PD-1 blockade-induced reinvigoration and that loss of CD28 expression serves as a marker of anti-PD-1 antibody-unresponsive CD8^(+)TILs.Transcriptionally and phenotypically,PD-1 blockade-unresponsive human CD28^(–)PD-1^(+)CD8^(+)TILs exhibited characteristics of terminally exhausted CD8^(+)T cells with low TCF1 expression.Notably,CD28^(–)PD-1^(+)CD8^(+)TILs had preserved machinery to respond to IL-15,and IL-15 treatment enhanced the proliferation of CD28^(–)PD-1^(+)CD8^(+)TILs as well as CD28^(+)PD-1^(+)CD8^(+)TILs.Taken together,these results show that loss of CD28 expression is a marker of PD-1 blockade-unresponsive human CD8^(+)TILs with a TCF1–signature and provide mechanistic insights into combining IL-15 with anti-PD-1 antibodies.
基金supported by the National Key R&D Program of China(2017YFAO105803)the general program of the National Natural Science Foundation of China(81770826)+2 种基金the Science and Technology Plan Projects of Guangdong Province(2019B020227003)the Key Special Projects of Medical and Health of Guangzhou City(202007040003)the 5010 Clinical Research Projects of Sun Yatsen University(2015015).
文摘Type 1 diabetes mellitus(T1D)is a chronic autoimmune condition in which the immune system destroys insulin-producing pancreatic β cells.In addition to well-established pathogenic effector T cells,regulatory T cells(Tregs)have also been shown to be defective in T1D.Thus,an increasing number of therapeutic approaches are being developed to target Tregs.However,the role and mechanisms of TGF-β-induced Tregs(iTregs)in T1D remain poorly understood.Here,using a streptozotocin(STZ)-induced preclinical T1D mouse model,we found that iTregs could ameliorate the development of T1D and preserve β cell function.The preventive effect was associated with the inhibition of type 1 cytotoxic T(Tel)cell function and rebalancing the Treg/Tc1 cell ratio in recipients.Furthermore,we showed that the underlying mechanisms were due to the TGF-β-mediated combinatorial actions of mTOR and TCF1.In addition to the preventive role,the therapeutic effects of iTregs on the established STZ-T1D and nonobese diabetic(NOD)mouse models were tested,which revealed improved β cell function.Our findings therefore provide key new insights into the basic mechanisms involved in the therapeutic role of iTregs in T1D.
