Chinese hamster ovary(CHO)cells are crucial in biopharmaceutical production due to their scalability and capacity for human-like post-translational modifications.However,toxic proteins and membrane proteins are often ...Chinese hamster ovary(CHO)cells are crucial in biopharmaceutical production due to their scalability and capacity for human-like post-translational modifications.However,toxic proteins and membrane proteins are often difficult-to-express in living cells.Alternatively,cell-free protein synthesis can be employed.This study explores innovative strategies for enhancing the production of challenging proteins through the modification of CHO cells by investigating both,cell-based and cell-free approaches.A major result in our study involves the integration of a mutant eIF2 translation initiation factor and T7 RNA polymerase into CHO cell lysates for cell-free protein synthesis.This resulted in elevated yields,while eliminating the necessity for exogenous additions during cell-free production,thereby substantially enhancing efficiency.Additionally,we explore the potential of the Rosa26 genomic site for the integration of T7 RNA polymerase and cell-based tetracycline-controlled protein expression.These findings provide promising advancements in bioproduction technologies,offering flexibility to switch between cell-free and cell-based protein production as needed.展开更多
PKR, the interferon （IFN）-inducible protein kinase activated by double-stranded RNA, inhibits translation by phosphorylating the initiation factor eIF2α chain. Uniquely, human IFN-γ mRNA uses local activation of P...PKR, the interferon （IFN）-inducible protein kinase activated by double-stranded RNA, inhibits translation by phosphorylating the initiation factor eIF2α chain. Uniquely, human IFN-γ mRNA uses local activation of PKR in the cell to control its own translation yield. IFN-γ mRNA activates PKR through a structure in its 5＇- region harboring a pseudoknot which is critical for PKR activation. Mutations that impair pseudoknot stability reduce the ability of IFN-γ mRNA to activate PKR and strongly increase its translation efficiency. The cis-acting RNA element in IFN-γ mRNA functions as a biological sensor of intracellular PKR levels. During an immune response, as IFN-γ and other inflammatory cytokines build up in the cell＇s microenvironment, they act to induce higher levels of PKR in the cell, resulting in a more extensive activation of PKR by IFN-γ mRNA. With the resulting phosphorylation of eIF2α, a negative feedback loop is created and the production of IFN-γ is progressively attenuated. We propose that the therapeutic effect of IFN-β in multiple sclerosis may rest, at least in part, on its exquisite ability to induce high levels of PKR in the cell and thereby to limit IFN-γ mRNA translation through this negative feedback loop, blocking the excessive IFN-γ gene expression that precedes clinical attacks.展开更多
Objective: To examine the effect of pSer9-GSK-3β on breast cancer and to determine whether the underlying metabolic and immunological mechanism is associated with ROS/eIF2B and natural killer(NK) cells.Methods: We em...Objective: To examine the effect of pSer9-GSK-3β on breast cancer and to determine whether the underlying metabolic and immunological mechanism is associated with ROS/eIF2B and natural killer(NK) cells.Methods: We employed TWS119 to inactivate GSK-3β by phosphorylating Ser9 and explored its effect on breast cancer and NK cells. The expression of GSK-3β, natural killer group 2 member D(NKG2D) ligands, eIF2B was quantified by PCR and Western blot. We measured intracellular reactive oxygen species(ROS) and mitochondrial ROS using DCFH-DA and MitoSOX^(TM) probe,respectively, and conducted quantitative analysis of cellular respiration on 4T1 cells with mitochondrial respiratory chain complex Ⅰ/Ⅲ kits.Results: Our investigation revealed that TWS119 downregulated NKG2D ligands(H60 a and Rae1), suppressed the cytotoxicity of NK cells, and promoted the migration of 4T1 murine breast cancer cells. Nevertheless, LY290042, which attenuates p-GSK-3β formation by inhibiting the PI3K/Akt pathway, reversed these effects. We also found that higher expression of p Ser9-GSK-3β induced higher levels of ROS, and observed that abnormality of mitochondrial respiratory chain complex Ⅰ/Ⅲ function induced the dysfunction of GSK-3β-induced electron transport chain, naturally disturbing the ROS level. In addition, the expression of NOX3 and NOX4 was significantly up-regulated, which affected the generation of ROS and associated with the metastasis of breast cancer. Furthermore, we found that the expression of pSer535-eIF2B promoted the expression of NKG2D ligands(Mult-1 and Rae1) following by expression of pSer9-GSK-3β and generation of ROS.Conclusions: The PI3K/Akt/GSK-3β/ROS/eIF2B pathway could regulate NK cell activity and sensitivity of tumor cells to NK cells,which resulted in breast cancer growth and lung metastasis. Thus, GSK-3β is a promising target of anti-tumor therapy.展开更多
5-Hydroxymethylfurfural （5-HMF）, a water-soluble compound extracted from wine-processed Fructus corni, is a novel hepatic protectant for treating acute liver injury. The present study was designed to investigate the...5-Hydroxymethylfurfural （5-HMF）, a water-soluble compound extracted from wine-processed Fructus corni, is a novel hepatic protectant for treating acute liver injury. The present study was designed to investigate the protective effect of 5-HMF in human L02 hepatocytes injured by D-galactosamine （GAIN） and tumor necrosis factor-α （TNF-α） in vitro and to explore the underlying mechanisms of action. Our results showed that 5-HMF caused significant increase in the viability of L02 cells injured by GalN/TNF-α, in accordance with a dose-dependent decrease in apoptotic cell death confirmed by morphological and flow cytometric analyses. Based on immunofluorescence and Western blot assays, we found that GalN/TNF-α induced ER stress in the cells, as indicated by the disturbance of intracellular Ca^2＋ concentration, the activation of protein kinase RNA （PKR）-like ER kinase （PERK）, phosphorylation of eukaryotic initiation factor 2 alpha （eIF2α）, and expression of ATF4 and CHOP proteins, which was reversed by 5-HMF pre-treatment in a dose-dependent manner. The anti-apoptotic effect of 5-HMF was further evidenced by balancing the expression of Bcl-2 family members. In addition, the knockdown of PERK suppressed the expression of phospho-PERK, phospho-eIF2α, ATF4, and CHOP, resulting in a significant decrease in cell apoptosis after the treatment with GalN/TNF-α. 5-HMF could enhance the effects of PERK knockdown, protecting the cells against the GalN/TNF-α insult. In conclusion, these findings demonstrate that 5-HMF can effectively protect GalN/TNF-α-injured L02 hepatocytes against ER stress-induced apoptosis through the regulation of the PERK- eIF2α signaling pathway, suggesting that it is a possible candidate for liver disease therapy.展开更多
Apoptosis induced by endoplasmic reticulum(ER)stress plays a crucial role in mediating brain damage after ischemic stroke.Recently,Hes1(hairy and enhancer of split 1)has been implicated in the regulation of ER stress,...Apoptosis induced by endoplasmic reticulum(ER)stress plays a crucial role in mediating brain damage after ischemic stroke.Recently,Hes1(hairy and enhancer of split 1)has been implicated in the regulation of ER stress,but whether it plays a functional role after ischemic stroke and the underlying mechanism remain unclear.In this study,using a mouse model of ischemic stroke via transient middle cerebral artery occlusion(tMCAO),we found that Hes1 was induced following brain injury,and that siRNA-mediated knockdown of Hes1 increased the cerebral infarction and worsened the neurological outcome,suggesting that Hes1 knockdown exacerbates ischemic stroke.In addition,mechanistically,Hes1 knockdown promoted apoptosis and activated the PERK/eIF2a/ATF4/CHOP signaling pathway after tMCAO.These results suggest that Hes1 knockdown promotes ER stress-induced apoptosis.Furthermore,inhibition of PERK with the specific inhibitor GSK2606414 markedly attenuated the Hes1 knockdown-induced apoptosis and the increased cerebral infarction as well as the worsened neurological outcome following tMCAO,implying that the protection of Hes1 against ischemic stroke is associated with the amelioration of ER stress via modulating the PERK/eIF2a/ATF4/CHOP signaling pathway.Taken together,these results unveil the detrimental role of Hes1 knockdown after ischemic stroke and further relate it to the regulation of ER stress-induced apoptosis,thus highlighting the importance of targeting ER stress in the treatment of ischemic stroke.展开更多
Using chemoproteomic techniques,we first identified EIF2AK2,eEF1A1,PRDX3 and VPS4B as direct targets of berberine(BBR)for its synergistically anti-inflammatory effects.Of them,BBR has the strongest affinity with EIF2A...Using chemoproteomic techniques,we first identified EIF2AK2,eEF1A1,PRDX3 and VPS4B as direct targets of berberine(BBR)for its synergistically anti-inflammatory effects.Of them,BBR has the strongest affinity with EIF2AK2 via two ionic bonds,and regulates several key inflammatory pathways through EIF2AK2,indicating the dominant role of EIF2AK2.Also,BBR could subtly inhibit the dimerization of EIF2AK2,rather than its enzyme activity,to selectively modulate its downstream pathways including JNK,NF-κB,AKT and NLRP3,with an advantage of good safety profile.In EIF2AK2 gene knockdown mice,the inhibitory IL-1β,IL-6,IL-18 and TNF-a secretion of BBR was obviously attenuated,confirming an EIF2AK2-dependent anti-inflammatory efficacy.The results highlight the BBR's network mechanism on anti-inflammatory effects in which EIF2AK2 is a key target,and inhibition of EIF2AK2 dimerization has a potential to be a therapeutic strategy against inflammationrelated disorders.展开更多
基金supported by the European Regional Development Fund(EFRE)and the German Ministry of Education and Research(BMBF 031B0831C).
文摘Chinese hamster ovary(CHO)cells are crucial in biopharmaceutical production due to their scalability and capacity for human-like post-translational modifications.However,toxic proteins and membrane proteins are often difficult-to-express in living cells.Alternatively,cell-free protein synthesis can be employed.This study explores innovative strategies for enhancing the production of challenging proteins through the modification of CHO cells by investigating both,cell-based and cell-free approaches.A major result in our study involves the integration of a mutant eIF2 translation initiation factor and T7 RNA polymerase into CHO cell lysates for cell-free protein synthesis.This resulted in elevated yields,while eliminating the necessity for exogenous additions during cell-free production,thereby substantially enhancing efficiency.Additionally,we explore the potential of the Rosa26 genomic site for the integration of T7 RNA polymerase and cell-based tetracycline-controlled protein expression.These findings provide promising advancements in bioproduction technologies,offering flexibility to switch between cell-free and cell-based protein production as needed.
基金Acknowledgements Research in the author＇s laboratory was supported by grants from the Israel Science Foundation （537/03） and the Deutsche Forschungsgemeinschaft （H0- 1116）,
文摘PKR, the interferon （IFN）-inducible protein kinase activated by double-stranded RNA, inhibits translation by phosphorylating the initiation factor eIF2α chain. Uniquely, human IFN-γ mRNA uses local activation of PKR in the cell to control its own translation yield. IFN-γ mRNA activates PKR through a structure in its 5＇- region harboring a pseudoknot which is critical for PKR activation. Mutations that impair pseudoknot stability reduce the ability of IFN-γ mRNA to activate PKR and strongly increase its translation efficiency. The cis-acting RNA element in IFN-γ mRNA functions as a biological sensor of intracellular PKR levels. During an immune response, as IFN-γ and other inflammatory cytokines build up in the cell＇s microenvironment, they act to induce higher levels of PKR in the cell, resulting in a more extensive activation of PKR by IFN-γ mRNA. With the resulting phosphorylation of eIF2α, a negative feedback loop is created and the production of IFN-γ is progressively attenuated. We propose that the therapeutic effect of IFN-β in multiple sclerosis may rest, at least in part, on its exquisite ability to induce high levels of PKR in the cell and thereby to limit IFN-γ mRNA translation through this negative feedback loop, blocking the excessive IFN-γ gene expression that precedes clinical attacks.
基金supported by grants from the National Natural Science Foundation of China (Grant No. 8117975 and 31770968)Tianjin Institutes for Basic Sciences (Grant No. 15JCYBJC26900 and 16JCQNJC11700)
文摘Objective: To examine the effect of pSer9-GSK-3β on breast cancer and to determine whether the underlying metabolic and immunological mechanism is associated with ROS/eIF2B and natural killer(NK) cells.Methods: We employed TWS119 to inactivate GSK-3β by phosphorylating Ser9 and explored its effect on breast cancer and NK cells. The expression of GSK-3β, natural killer group 2 member D(NKG2D) ligands, eIF2B was quantified by PCR and Western blot. We measured intracellular reactive oxygen species(ROS) and mitochondrial ROS using DCFH-DA and MitoSOX^(TM) probe,respectively, and conducted quantitative analysis of cellular respiration on 4T1 cells with mitochondrial respiratory chain complex Ⅰ/Ⅲ kits.Results: Our investigation revealed that TWS119 downregulated NKG2D ligands(H60 a and Rae1), suppressed the cytotoxicity of NK cells, and promoted the migration of 4T1 murine breast cancer cells. Nevertheless, LY290042, which attenuates p-GSK-3β formation by inhibiting the PI3K/Akt pathway, reversed these effects. We also found that higher expression of p Ser9-GSK-3β induced higher levels of ROS, and observed that abnormality of mitochondrial respiratory chain complex Ⅰ/Ⅲ function induced the dysfunction of GSK-3β-induced electron transport chain, naturally disturbing the ROS level. In addition, the expression of NOX3 and NOX4 was significantly up-regulated, which affected the generation of ROS and associated with the metastasis of breast cancer. Furthermore, we found that the expression of pSer535-eIF2B promoted the expression of NKG2D ligands(Mult-1 and Rae1) following by expression of pSer9-GSK-3β and generation of ROS.Conclusions: The PI3K/Akt/GSK-3β/ROS/eIF2B pathway could regulate NK cell activity and sensitivity of tumor cells to NK cells,which resulted in breast cancer growth and lung metastasis. Thus, GSK-3β is a promising target of anti-tumor therapy.
基金supported by grants from Natural Science Foundation of Jiangsu Higher Education Institutions of China(No.13KJB360010)Jiangsu Collaborative Innovation Center of Traditional Chinese Medicine(TCM) Prevention and Treatment of Tumor(No.012092002002)+1 种基金China and Europe Taking Care of Healthcare Solutions,CHETCH(No.PIRSES-GA-2013-612589)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘5-Hydroxymethylfurfural （5-HMF）, a water-soluble compound extracted from wine-processed Fructus corni, is a novel hepatic protectant for treating acute liver injury. The present study was designed to investigate the protective effect of 5-HMF in human L02 hepatocytes injured by D-galactosamine （GAIN） and tumor necrosis factor-α （TNF-α） in vitro and to explore the underlying mechanisms of action. Our results showed that 5-HMF caused significant increase in the viability of L02 cells injured by GalN/TNF-α, in accordance with a dose-dependent decrease in apoptotic cell death confirmed by morphological and flow cytometric analyses. Based on immunofluorescence and Western blot assays, we found that GalN/TNF-α induced ER stress in the cells, as indicated by the disturbance of intracellular Ca^2＋ concentration, the activation of protein kinase RNA （PKR）-like ER kinase （PERK）, phosphorylation of eukaryotic initiation factor 2 alpha （eIF2α）, and expression of ATF4 and CHOP proteins, which was reversed by 5-HMF pre-treatment in a dose-dependent manner. The anti-apoptotic effect of 5-HMF was further evidenced by balancing the expression of Bcl-2 family members. In addition, the knockdown of PERK suppressed the expression of phospho-PERK, phospho-eIF2α, ATF4, and CHOP, resulting in a significant decrease in cell apoptosis after the treatment with GalN/TNF-α. 5-HMF could enhance the effects of PERK knockdown, protecting the cells against the GalN/TNF-α insult. In conclusion, these findings demonstrate that 5-HMF can effectively protect GalN/TNF-α-injured L02 hepatocytes against ER stress-induced apoptosis through the regulation of the PERK- eIF2α signaling pathway, suggesting that it is a possible candidate for liver disease therapy.
基金supported by grants from the Guangxi Zhuang Autonomous Region Health and Family Planning Commission Science and Technology Project(Z2016419)Guangxi Natural Science Foundation Project(No.:2018JJA140853)the Science and Technology Project of Hunan Province,China(2014FJ4233).
文摘Apoptosis induced by endoplasmic reticulum(ER)stress plays a crucial role in mediating brain damage after ischemic stroke.Recently,Hes1(hairy and enhancer of split 1)has been implicated in the regulation of ER stress,but whether it plays a functional role after ischemic stroke and the underlying mechanism remain unclear.In this study,using a mouse model of ischemic stroke via transient middle cerebral artery occlusion(tMCAO),we found that Hes1 was induced following brain injury,and that siRNA-mediated knockdown of Hes1 increased the cerebral infarction and worsened the neurological outcome,suggesting that Hes1 knockdown exacerbates ischemic stroke.In addition,mechanistically,Hes1 knockdown promoted apoptosis and activated the PERK/eIF2a/ATF4/CHOP signaling pathway after tMCAO.These results suggest that Hes1 knockdown promotes ER stress-induced apoptosis.Furthermore,inhibition of PERK with the specific inhibitor GSK2606414 markedly attenuated the Hes1 knockdown-induced apoptosis and the increased cerebral infarction as well as the worsened neurological outcome following tMCAO,implying that the protection of Hes1 against ischemic stroke is associated with the amelioration of ER stress via modulating the PERK/eIF2a/ATF4/CHOP signaling pathway.Taken together,these results unveil the detrimental role of Hes1 knockdown after ischemic stroke and further relate it to the regulation of ER stress-induced apoptosis,thus highlighting the importance of targeting ER stress in the treatment of ischemic stroke.
基金the CAMS initiative for innovative medicine(2022-I2M-2-002,China)National Natural Science Foundation of China(32141003)。
文摘Using chemoproteomic techniques,we first identified EIF2AK2,eEF1A1,PRDX3 and VPS4B as direct targets of berberine(BBR)for its synergistically anti-inflammatory effects.Of them,BBR has the strongest affinity with EIF2AK2 via two ionic bonds,and regulates several key inflammatory pathways through EIF2AK2,indicating the dominant role of EIF2AK2.Also,BBR could subtly inhibit the dimerization of EIF2AK2,rather than its enzyme activity,to selectively modulate its downstream pathways including JNK,NF-κB,AKT and NLRP3,with an advantage of good safety profile.In EIF2AK2 gene knockdown mice,the inhibitory IL-1β,IL-6,IL-18 and TNF-a secretion of BBR was obviously attenuated,confirming an EIF2AK2-dependent anti-inflammatory efficacy.The results highlight the BBR's network mechanism on anti-inflammatory effects in which EIF2AK2 is a key target,and inhibition of EIF2AK2 dimerization has a potential to be a therapeutic strategy against inflammationrelated disorders.
