Endoplasmic reticulum(ER)stress occurs when ER homeostasis is perturbed with accumulation of unfolded/misfolded protein or calcium depletion.The unfolded protein response(UPR),comprising of inositol-requiring enzyme 1...Endoplasmic reticulum(ER)stress occurs when ER homeostasis is perturbed with accumulation of unfolded/misfolded protein or calcium depletion.The unfolded protein response(UPR),comprising of inositol-requiring enzyme 1 a(IRE1 a),double-stranded RNA-dependent protein kinase(PKR)-like ER kinase(PERK)and activating transcription factor 6(ATF6)signaling pathways,is a protective cellular response activated by ER stress.However,UPR activation can also induce cell death upon persistent ER stress.The liver is susceptible to ER stress given its synthetic and other biological functions.Numerous studies from human liver samples and animal disease models have indicated a crucial role of ER stress and the UPR signaling pathways in the pathogenesis of liver diseases,including non-alcoholic fatty liver disease(NAFLD),alcoholic liver disease(ALD),alpha-1 antitrypsin(AAT)deficiency(AATD),cholestatic liver disease,drug-induced liver injury,ischemia/reperfusion(I/R)injury,viral hepatitis and hepatocel-lular carcinoma(HCC).Extensive investigations have demonstrated the potential underlying mechanisms of the induction of ER stress and the contribution of the UPR pathways during the development of the diseases.Moreover,ER stress and the UPR proteins and genes have become emerging therapeutic targets to treat liver diseases.展开更多
In the process of tumor proliferation and metastasis,tumor cells encounter hypoxia,low glucose,acidosis,and other stressful environments.These conditions prompt tumor cells to generate endoplasmic reticulum stress(ERS...In the process of tumor proliferation and metastasis,tumor cells encounter hypoxia,low glucose,acidosis,and other stressful environments.These conditions prompt tumor cells to generate endoplasmic reticulum stress(ERS).As a signal mechanism that mitigates ERS in eukaryotic cells,the unfolded protein response(UPR)pathway can activate cells and tissues,regulating pathological activities in various cells,and maintaining ER homeostasis.It forms the most crucial adaptive and defensive mechanism for cells.However,under the continuous influence of chemotherapy drugs,the quantity of unfolded proteins and erroneous proteins produced by tumor cells significantly increases,surpassing the normal regulatory range of UPR.Consequently,ERS fails to function properly,fostering tumor cell proliferation and the development of drug resistance.This review delves into the study of three UPR pathways(PERK,IRE1,and ATF6),elucidating the mechanisms of drug resistance and research progress in the signal transduction pathway of UPR related to cancers.It provides a profound understanding of the role and relationship between UPR and anti-tumor drugs,offering a new direction for effective clinical treatment.展开更多
[Objectives] To study the therapeutic effect and mechanism of New Maixian Powder on ulcerative colitis( UC) rats through observing its regulatory effect on the protein kinase R-like endoplasmic reticulum kinase( PERK)...[Objectives] To study the therapeutic effect and mechanism of New Maixian Powder on ulcerative colitis( UC) rats through observing its regulatory effect on the protein kinase R-like endoplasmic reticulum kinase( PERK)/eukaryotic translation initiation factor-2α( e IF-2α)/nuclear transcription factor-kappa B( NF-κB) signaling pathway. [Methods]First,60 SD rats were randomly divided into normal group,model group,mesalazine group,and New Maixian Powder low,medium and high dose groups,10 rats each group. Then,dextran sulfate sodium( DSS) was used to induce UC rats. The mesalazine group was given 0. 42 g/( kg·d) of mesalazine sustained-release granule suspension,New Maixian Powder low,medium and high dose groups were given 1. 5,3,and 6 g/( kg·d) of New Maixian Powder suspension,respectively,and other groups were given an equal volume of physiological saline,continuous intragastric administration for 14 d. Next,the disease activity index( DAI) of UC rats was evaluated; the expression of NF-κB in serum was measured by enzyme-linked immunosorbent assay( ELISA); the expression of PERK and e IF-2α protein and m RNA in colon tissue was detected by Western blot and real-time quantitative polymerase chain reaction( RT q-PCR). [Results] Compared with the normal group,the DAI score and serum NF-κB level in the model group were significantly higher( P < 0. 05),and PERK and e IF-2α protein and m RNA levels in the colon tissue were increased( P < 0. 05); compared with the model group,the DAI score decreased and serum NF-κB level declined in the New Maixian Powder group,and the expression of PERK and e IF-2α protein and m RNA in New Maixian Powder medium dose and high dose groups declined( P < 0. 05). [Conclusions]New Maixian Powder has good therapeutic effect on UC rats,and its mechanism may be connected with the inhibition of the activation of PERK/e IF-2α/NF-κB signaling pathway.展开更多
Objective:To examine whether exposure of mouse neuronal cells to radiofrequency fields used in mobile communication devices can induce stress in endoplasmic reticulum(ER)and activate unfolded protein response(UPR).Met...Objective:To examine whether exposure of mouse neuronal cells to radiofrequency fields used in mobile communication devices can induce stress in endoplasmic reticulum(ER)and activate unfolded protein response(UPR).Methods:HT22 mouse hippocampus neuronal cells were exposed to continuous wave 900 MHz radiofrequency fields(RF)at 120μW/cm2 power intensity for 4 h/d for 5 consecutive days.The positive control cells were irradiated with 4 Gy of 60Coγ-rays at a dose rate of 0.5 Gy/min(GR).Twenty-four hours after the last exposure,cells were collected,and the expressions of sensor transmembrane proteins were detected using Western blot analysis.Results:The expression levels of Ire1,PERK,p-IRE1 and p-PERK,GRP78 and CHOP proteins were detected.There were no statistically significant differences in the expression levels of IRE1 and PERK proteins in control(CT),sham(SH)-,RF-and GR-exposed cells(P<0.05).The phosphorylated protein levels of p-IRE1 and p-PERK were significantly increased in cells exposed to RF and GR(P<0.05).The expression levels of GRP78 and CHOP were significantly increased in RF-and GR-exposed cells compared to CT and SH-exposed cells(P<0.05).Cells treated with 1μg/ml TM for 24 h showed significantly increased expression levels of GRP78 and CHOP proteins compared to controls(P<0.05).In the presence of 2 mmol/L PBA,TM-induced increased levels of GRP78 and CHOP proteins were reduced(P<0.05).Conclusions:The exposure of non-ionizing 900 MHz RF was able to cause stress in HT22 mouse neuronal cells and activated UPR in ER.Since UPR plays an important role in both cell survival(when UPR is mitigated)and apoptosis/death(under unresolvable stress conditions),further studies are required to determine the fate of the cells exposed to RF.展开更多
基金This work was supported by USA National Institute of Diabetes and Digestive and Kidney Diseases(NIDDK)R01 DK093807.
文摘Endoplasmic reticulum(ER)stress occurs when ER homeostasis is perturbed with accumulation of unfolded/misfolded protein or calcium depletion.The unfolded protein response(UPR),comprising of inositol-requiring enzyme 1 a(IRE1 a),double-stranded RNA-dependent protein kinase(PKR)-like ER kinase(PERK)and activating transcription factor 6(ATF6)signaling pathways,is a protective cellular response activated by ER stress.However,UPR activation can also induce cell death upon persistent ER stress.The liver is susceptible to ER stress given its synthetic and other biological functions.Numerous studies from human liver samples and animal disease models have indicated a crucial role of ER stress and the UPR signaling pathways in the pathogenesis of liver diseases,including non-alcoholic fatty liver disease(NAFLD),alcoholic liver disease(ALD),alpha-1 antitrypsin(AAT)deficiency(AATD),cholestatic liver disease,drug-induced liver injury,ischemia/reperfusion(I/R)injury,viral hepatitis and hepatocel-lular carcinoma(HCC).Extensive investigations have demonstrated the potential underlying mechanisms of the induction of ER stress and the contribution of the UPR pathways during the development of the diseases.Moreover,ER stress and the UPR proteins and genes have become emerging therapeutic targets to treat liver diseases.
文摘In the process of tumor proliferation and metastasis,tumor cells encounter hypoxia,low glucose,acidosis,and other stressful environments.These conditions prompt tumor cells to generate endoplasmic reticulum stress(ERS).As a signal mechanism that mitigates ERS in eukaryotic cells,the unfolded protein response(UPR)pathway can activate cells and tissues,regulating pathological activities in various cells,and maintaining ER homeostasis.It forms the most crucial adaptive and defensive mechanism for cells.However,under the continuous influence of chemotherapy drugs,the quantity of unfolded proteins and erroneous proteins produced by tumor cells significantly increases,surpassing the normal regulatory range of UPR.Consequently,ERS fails to function properly,fostering tumor cell proliferation and the development of drug resistance.This review delves into the study of three UPR pathways(PERK,IRE1,and ATF6),elucidating the mechanisms of drug resistance and research progress in the signal transduction pathway of UPR related to cancers.It provides a profound understanding of the role and relationship between UPR and anti-tumor drugs,offering a new direction for effective clinical treatment.
基金Supported by Science and Technology Program of Zhejiang Province(2016C33085)
文摘[Objectives] To study the therapeutic effect and mechanism of New Maixian Powder on ulcerative colitis( UC) rats through observing its regulatory effect on the protein kinase R-like endoplasmic reticulum kinase( PERK)/eukaryotic translation initiation factor-2α( e IF-2α)/nuclear transcription factor-kappa B( NF-κB) signaling pathway. [Methods]First,60 SD rats were randomly divided into normal group,model group,mesalazine group,and New Maixian Powder low,medium and high dose groups,10 rats each group. Then,dextran sulfate sodium( DSS) was used to induce UC rats. The mesalazine group was given 0. 42 g/( kg·d) of mesalazine sustained-release granule suspension,New Maixian Powder low,medium and high dose groups were given 1. 5,3,and 6 g/( kg·d) of New Maixian Powder suspension,respectively,and other groups were given an equal volume of physiological saline,continuous intragastric administration for 14 d. Next,the disease activity index( DAI) of UC rats was evaluated; the expression of NF-κB in serum was measured by enzyme-linked immunosorbent assay( ELISA); the expression of PERK and e IF-2α protein and m RNA in colon tissue was detected by Western blot and real-time quantitative polymerase chain reaction( RT q-PCR). [Results] Compared with the normal group,the DAI score and serum NF-κB level in the model group were significantly higher( P < 0. 05),and PERK and e IF-2α protein and m RNA levels in the colon tissue were increased( P < 0. 05); compared with the model group,the DAI score decreased and serum NF-κB level declined in the New Maixian Powder group,and the expression of PERK and e IF-2α protein and m RNA in New Maixian Powder medium dose and high dose groups declined( P < 0. 05). [Conclusions]New Maixian Powder has good therapeutic effect on UC rats,and its mechanism may be connected with the inhibition of the activation of PERK/e IF-2α/NF-κB signaling pathway.
基金This research is supported by funding from the National Natural Science Foundation of China(Grant No.81373025).
文摘Objective:To examine whether exposure of mouse neuronal cells to radiofrequency fields used in mobile communication devices can induce stress in endoplasmic reticulum(ER)and activate unfolded protein response(UPR).Methods:HT22 mouse hippocampus neuronal cells were exposed to continuous wave 900 MHz radiofrequency fields(RF)at 120μW/cm2 power intensity for 4 h/d for 5 consecutive days.The positive control cells were irradiated with 4 Gy of 60Coγ-rays at a dose rate of 0.5 Gy/min(GR).Twenty-four hours after the last exposure,cells were collected,and the expressions of sensor transmembrane proteins were detected using Western blot analysis.Results:The expression levels of Ire1,PERK,p-IRE1 and p-PERK,GRP78 and CHOP proteins were detected.There were no statistically significant differences in the expression levels of IRE1 and PERK proteins in control(CT),sham(SH)-,RF-and GR-exposed cells(P<0.05).The phosphorylated protein levels of p-IRE1 and p-PERK were significantly increased in cells exposed to RF and GR(P<0.05).The expression levels of GRP78 and CHOP were significantly increased in RF-and GR-exposed cells compared to CT and SH-exposed cells(P<0.05).Cells treated with 1μg/ml TM for 24 h showed significantly increased expression levels of GRP78 and CHOP proteins compared to controls(P<0.05).In the presence of 2 mmol/L PBA,TM-induced increased levels of GRP78 and CHOP proteins were reduced(P<0.05).Conclusions:The exposure of non-ionizing 900 MHz RF was able to cause stress in HT22 mouse neuronal cells and activated UPR in ER.Since UPR plays an important role in both cell survival(when UPR is mitigated)and apoptosis/death(under unresolvable stress conditions),further studies are required to determine the fate of the cells exposed to RF.