Objective:PD-L1 and PD-L2 expression levels determine immune evasion and the therapeutic efficacy of immune checkpoint blockade.The factors that drive inducible PD-L1 expression have been extensively studied,but mecha...Objective:PD-L1 and PD-L2 expression levels determine immune evasion and the therapeutic efficacy of immune checkpoint blockade.The factors that drive inducible PD-L1 expression have been extensively studied,but mechanisms that result in constitutive PD-L1 expression in cancer cells are largely unknown.Methods:DNA elements were deleted in cells by CRISPR/Cas9-mediated knockout.Protein function was inhibited by chemical inhibitors.Protein levels were examined by Western blot,mRNA levels were examined by real-time RT-PCR,and surface protein expression was determined by cellular immunofluorescence and flow cytometry.Immune evasion was examined by in vitro T cell-mediated killing.Results:We determined the core regions(chr9:5,496,378–5,499,663)of a previously identified PD-L1L2-super-enhancer(SE).Through systematic analysis,we found that the E26 transformation-specific(ETS)variant transcription factor(ETV4)bound to this core DNA region but not to DNA surrounding PD-L1L2SE.Genetic knockout of ETV4 dramatically reduced the expressions of both PD-L1 and PD-L2.ETV4 transcription was dependent on ERK activation,and BRAF/TAK1-induced ERK activation was dependent on extracellular signaling fromαvβ3 integrin,which profoundly affected ETV4 transcription and PD-L1/L2 expression.Genetic silencing or pharmacological inhibition of components of the PD-L1L2-SE-associated pathway rendered cancer cells susceptible to T cell-mediated killing.Conclusions:We identified a pathway originating from the extracellular matrix that signaled via integrin/BRAF/TAK1/ERK/ETV4 to PD-L1L2-SE to induce PD-L1-mediated immune evasion.These results provided new insights into PD-L1L2-SE activation and pathways associated with immune checkpoint regulation in cancer.展开更多
Background Hepatic inflammation is the major risk factor of hepatocellular carcinoma(HCC).However,the underlying mechanism by which hepatic inflammation progresses to HCC is poorly understood.This study was designed t...Background Hepatic inflammation is the major risk factor of hepatocellular carcinoma(HCC).However,the underlying mechanism by which hepatic inflammation progresses to HCC is poorly understood.This study was designed to investigate the role of ETS translocation variant 4(ETV4)in linking hepatic inflammation to HCC.Methods Quantitative real-time PCR and immunoblotting were used to detect the expression of ETV4 in HCC tissues and cell lines.RNA sequencing and luciferase reporter assays were performed to identify the target genes of ETV4.Hepatocyte-specific ETV4-knockout(ETV4fl/fl,alb-cre)and transgenic(ETV4Hep-TG)mice and diethylnitrosamine-carbon tetrachloride(DEN-CCL4)treatment experiments were applied to investigate the function of ETV4 in vivo.The Cancer Genome Atlas(TCGA)database mining and pathological analysis were carried out to determine the correlation of ETV4 with tumor necrosis factor-alpha(TNF-α)and mitogen-activated protein kinase 11(MAPK11).Results We revealed that ETV4 was highly expressed in HCC.High levels of ETV4 predicted a poor survival rate of HCC patients.Then we identified ETV4 as a transcription activator of TNF-αand MAPK11.ETV4 was positively correlated with TNF-αand MAPK11 in HCC patients.As expected,an increase in hepatic TNF-αsecretion and macrophage accumulation were observed in the livers of ETV4Hep-TG mice.The protein levels of TNF-α,MAPK11,and CD68 were significantly higher in the livers of ETV4Hep-TG mice compared with wild type mice but lower in ETV4fl/fl,alb-cre mice compared with ETV4fl/fl mice as treated with DEN-CCL4,indicating that ETV4 functioned as a driver of TNF-α/MAPK11 expression and macrophage accumulation during hepatic inflammation.Hepatocyte-specific knockout of ETV4 significantly prevented development of DEN-CCL4-induced HCC,while transgenic expression of ETV4 promoted growth of HCC.Conclusions ETV4 promoted hepatic inflammation and HCC by activating transcription of TNF-αand MAPK11.Both the ETV4/TNF-αand ETV4/MAPK11 axes represented two potential therapeutic targets for highly associated hepatic inflammation and HCC.ETV4+TNF-αwere potential prognostic markers for HCC patients.展开更多
The raphe nucleus is critical for feeding, rewarding and memory. However, how the heterogenous raphe neurons are molecularly and structurally organized to engage their divergent functions remains unknown. Here, we gen...The raphe nucleus is critical for feeding, rewarding and memory. However, how the heterogenous raphe neurons are molecularly and structurally organized to engage their divergent functions remains unknown. Here, we genetically target a subset of neurons expressing VGLUT3. VGLUT3 neurons control the efficacy of spatial memory retrieval by synapsing directly with parvalbumin-expressing GABA interneurons(PGIs) in the dentate gyrus. In a mouse model of Alzheimer's disease(AD mice),VGLUT3→PGIs synaptic transmission is impaired by ETV4 inhibition of VGLUT3 transcription. ETV4 binds to a promoter region of VGLUT3 and activates VGLUT3 transcription in VGLUT3 neurons. Strengthening VGLUT3→PGIs synaptic transmission by ETV4 activation of VGLUT3 transcription upscales the efficacy of spatial memory retrieval in AD mice. This study reports a novel circuit and molecular mechanism underlying the efficacy of spatial memory retrieval via ETV4 inhibition of VGLUT3 transcription and hence provides a promising target for therapeutic intervention of the disease progression.展开更多
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.81600386,81641164,31770935,and 81873531)the Distinguished Professorship Program of Jiangsu Province to Yihui Fan,the Distinguished Professorship Program of Jiangsu Province to Renfang Mao,and the National Undergraduate Training Programs for Innovation(Grant No.202010304109Y).
文摘Objective:PD-L1 and PD-L2 expression levels determine immune evasion and the therapeutic efficacy of immune checkpoint blockade.The factors that drive inducible PD-L1 expression have been extensively studied,but mechanisms that result in constitutive PD-L1 expression in cancer cells are largely unknown.Methods:DNA elements were deleted in cells by CRISPR/Cas9-mediated knockout.Protein function was inhibited by chemical inhibitors.Protein levels were examined by Western blot,mRNA levels were examined by real-time RT-PCR,and surface protein expression was determined by cellular immunofluorescence and flow cytometry.Immune evasion was examined by in vitro T cell-mediated killing.Results:We determined the core regions(chr9:5,496,378–5,499,663)of a previously identified PD-L1L2-super-enhancer(SE).Through systematic analysis,we found that the E26 transformation-specific(ETS)variant transcription factor(ETV4)bound to this core DNA region but not to DNA surrounding PD-L1L2SE.Genetic knockout of ETV4 dramatically reduced the expressions of both PD-L1 and PD-L2.ETV4 transcription was dependent on ERK activation,and BRAF/TAK1-induced ERK activation was dependent on extracellular signaling fromαvβ3 integrin,which profoundly affected ETV4 transcription and PD-L1/L2 expression.Genetic silencing or pharmacological inhibition of components of the PD-L1L2-SE-associated pathway rendered cancer cells susceptible to T cell-mediated killing.Conclusions:We identified a pathway originating from the extracellular matrix that signaled via integrin/BRAF/TAK1/ERK/ETV4 to PD-L1L2-SE to induce PD-L1-mediated immune evasion.These results provided new insights into PD-L1L2-SE activation and pathways associated with immune checkpoint regulation in cancer.
基金National Key R&D Program of China,Grant/Award Numbers:2022YFC2303400,2022YFC2305205Strategic Priority Research Program of the Chinese Academy of Sciences,Grant/Award Number:XDB29010000。
文摘Background Hepatic inflammation is the major risk factor of hepatocellular carcinoma(HCC).However,the underlying mechanism by which hepatic inflammation progresses to HCC is poorly understood.This study was designed to investigate the role of ETS translocation variant 4(ETV4)in linking hepatic inflammation to HCC.Methods Quantitative real-time PCR and immunoblotting were used to detect the expression of ETV4 in HCC tissues and cell lines.RNA sequencing and luciferase reporter assays were performed to identify the target genes of ETV4.Hepatocyte-specific ETV4-knockout(ETV4fl/fl,alb-cre)and transgenic(ETV4Hep-TG)mice and diethylnitrosamine-carbon tetrachloride(DEN-CCL4)treatment experiments were applied to investigate the function of ETV4 in vivo.The Cancer Genome Atlas(TCGA)database mining and pathological analysis were carried out to determine the correlation of ETV4 with tumor necrosis factor-alpha(TNF-α)and mitogen-activated protein kinase 11(MAPK11).Results We revealed that ETV4 was highly expressed in HCC.High levels of ETV4 predicted a poor survival rate of HCC patients.Then we identified ETV4 as a transcription activator of TNF-αand MAPK11.ETV4 was positively correlated with TNF-αand MAPK11 in HCC patients.As expected,an increase in hepatic TNF-αsecretion and macrophage accumulation were observed in the livers of ETV4Hep-TG mice.The protein levels of TNF-α,MAPK11,and CD68 were significantly higher in the livers of ETV4Hep-TG mice compared with wild type mice but lower in ETV4fl/fl,alb-cre mice compared with ETV4fl/fl mice as treated with DEN-CCL4,indicating that ETV4 functioned as a driver of TNF-α/MAPK11 expression and macrophage accumulation during hepatic inflammation.Hepatocyte-specific knockout of ETV4 significantly prevented development of DEN-CCL4-induced HCC,while transgenic expression of ETV4 promoted growth of HCC.Conclusions ETV4 promoted hepatic inflammation and HCC by activating transcription of TNF-αand MAPK11.Both the ETV4/TNF-αand ETV4/MAPK11 axes represented two potential therapeutic targets for highly associated hepatic inflammation and HCC.ETV4+TNF-αwere potential prognostic markers for HCC patients.
基金supported by the National Natural Science Foundation of China (31721002, 81920208014, 31930051, 81800133)China Postdoctoral Science Foundation Funded Project (2018M642853)。
文摘The raphe nucleus is critical for feeding, rewarding and memory. However, how the heterogenous raphe neurons are molecularly and structurally organized to engage their divergent functions remains unknown. Here, we genetically target a subset of neurons expressing VGLUT3. VGLUT3 neurons control the efficacy of spatial memory retrieval by synapsing directly with parvalbumin-expressing GABA interneurons(PGIs) in the dentate gyrus. In a mouse model of Alzheimer's disease(AD mice),VGLUT3→PGIs synaptic transmission is impaired by ETV4 inhibition of VGLUT3 transcription. ETV4 binds to a promoter region of VGLUT3 and activates VGLUT3 transcription in VGLUT3 neurons. Strengthening VGLUT3→PGIs synaptic transmission by ETV4 activation of VGLUT3 transcription upscales the efficacy of spatial memory retrieval in AD mice. This study reports a novel circuit and molecular mechanism underlying the efficacy of spatial memory retrieval via ETV4 inhibition of VGLUT3 transcription and hence provides a promising target for therapeutic intervention of the disease progression.
