An increasing number of studies report that the Ras/Raf/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway has a death-promoting apoptotic function in neural cells. We hypothesized that the Ras/Raf...An increasing number of studies report that the Ras/Raf/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway has a death-promoting apoptotic function in neural cells. We hypothesized that the Ras/Raf/ERK1/2 signaling pathway may be abnormally regulated in rat injured spinal cord models. The weight drop method was used to establish rat spinal cord injury at T9. Western blot analysis and immunohistochemical staining revealed Ras expression was dramatically elevated, and the phosphorylations of A-Raf, B-Raf and C-Raf were all upregulated in the injured spinal cord. Both mitogen-activated protein kinase kinase 1/2 and ERK1/2, which belong to the Ras/Raf signaling kinases, were upregulated. These results indicate that Ras/Raf/ ERK1/2 signaling may be upregulated in injured spinal cord and are involved in recovery after spinal cord injury.展开更多
The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administratio...The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administration of T-AⅢ,the nude mice exhibited an induction of CYP2B10,MDR1,and CYP3A11 expression in the liver tissues.In the ICR mice,the expression levels of CYP2B10 and MDR1 increased after a three-day T-AⅢ administration.The in vitro assessments with HepG2 cells revealed that T-AⅢ induced the expression of CYP2B6,MDR1,and CYP3A4,along with constitutive androstane receptor(CAR)activation.Treatment with CAR siRNA reversed the T-AⅢ-induced increases in CYP2B6 and CYP3A4 expression.Furthermore,other CAR target genes also showed a significant increase in the expression.The up-regulation of murine CAR was observed in the liver tissues of both nude and ICR mice.Subsequent findings demonstrated that T-AⅢ activated CAR by inhibiting ERK1/2 phosphorylation,with this effect being partially reversed by the ERK activator t-BHQ.Inhibition of the ERK1/2 signaling pathway was also observed in vivo.Additionally,T-AⅢ inhibited the phosphorylation of EGFR at Tyr1173 and Tyr845,and suppressed EGF-induced phosphorylation of EGFR,ERK,and CAR.In the nude mice,T-AⅢ also inhibited EGFR phosphorylation.These results collectively indicate that T-AⅢ is a novel CAR activator through inhibition of the EGFR pathway.展开更多
[Objectives]To explore the neuroprotective effects and mechanism of Longan Aril(LA)effective parts on PC12 cells injured by H2O2.[Methods]The neuroprotective effects of LA were evaluated by the cell viability,SOD and ...[Objectives]To explore the neuroprotective effects and mechanism of Longan Aril(LA)effective parts on PC12 cells injured by H2O2.[Methods]The neuroprotective effects of LA were evaluated by the cell viability,SOD and MDA content,apoptosis assay and relative protein expression of Aβand p-Tau.The neuroprotective mechanism of LA was studied by using metabolomics and network pharmacology,and the expressions of RAS/MEK/ERK signaling pathway-related proteins were detected by western blotting.[Results]LA could improve the cell survival rate and SOD content,and reduce apoptosis and expression of Aβand p-tau.Inhibition of RAS/MEK/ERK signaling pathway is a possible mechanism of LA neuroprotective effects.[Conclusions]LA has a neuroprotective effects in vitro and be likely to inhibit the process of AD by inhibition of RAS/MEK/ERK signalling pathway.展开更多
BACKGROUND Insomnia is a disease where individuals cannot maintain a steady and stable sleep state or fail to fall asleep.Western medicine mainly uses sedatives and hypnotic drugs to treat insomnia,and long-term use i...BACKGROUND Insomnia is a disease where individuals cannot maintain a steady and stable sleep state or fail to fall asleep.Western medicine mainly uses sedatives and hypnotic drugs to treat insomnia,and long-term use is prone to drug resistance and other adverse reactions.Acupuncture has a good curative effect and unique advantages in the treatment of insomnia.AIM To explore the molecular mechanism of acupuncture at Back-Shu point for the treatment of insomnia.METHODS We first prepared a rat model of insomnia,and then carried out acupuncture for 7 consecutive days.After treatment,the sleep time and general behavior of the rats were determined.The Morris water maze test was used to assess the learning ability and spatial memory ability of the rats.The expression levels of inflammatory cytokines in serum and the hippocampus were detected by ELISA.qRTPCR was used to detect the mRNA expression changes in the ERK/NF-κB signaling pathway.Western blot and immunohistochemistry were carried out to evaluate the protein expression levels of RAF-1,MEK-2,ERK1/2 and NF-κB.RESULTS Acupuncture can prolong sleep duration,and improve mental state,activity,diet volume,learning ability and spatial memory.In addition,acupuncture increased the release of 1L-1β,1L-6 and TNF-αin serum and the hippocampus and inhibited the mRNA and protein expression of the ERK/NF-κB signaling pathway.CONCLUSION These findings suggest that acupuncture at Back-Shu point can inhibit the ERK/NF-κB signaling pathway and treat insomnia by increasing the release of inflammatory cytokines in the hippocampus.展开更多
Objective:To study the involvement of MAPK MEK/ERK signaling transduction pathway in the apoptosis process of SW620 tumor cell line and the inhibition effect of resveratrol.Methods:SW620 cell lines were divided into 5...Objective:To study the involvement of MAPK MEK/ERK signaling transduction pathway in the apoptosis process of SW620 tumor cell line and the inhibition effect of resveratrol.Methods:SW620 cell lines were divided into 5 groups,namely,control group.PD98059 group,low-dose resveratrol group,mid-dose resveratrol group and high-dose resveratrol group.The inhibition rate of cell proliferation was detected by MTT method.The expression of apoptotic molecules and MEK/ERK signaling pathway related proteins were assayed by realtime PCR and Western blotting.Results:Compared with control group,the proliferation of cells treated with resveratrol was significantly inhibited.In the case of apoptotic molecules,the expression of Bax,Caspase 3 and Caspase 9 was increased significantly while the expression of anti-apoptotic molecule Bcl2 was decreased significantly in resveratrol groups with a dosedependent manner.In the case of molecules in MEK/ERK signaling pathway,the expression of Ras,Raf,MEK and ERKl/2 was decreased significantly in resveratrol groups with a dose-dependent manner.Conclusions:PD98059 and resveratrol can effectively inhibit the proliferation of SW620 through inhibiting the MEK/ERK signaling pathway.展开更多
Objective To assess the effects of Yi Qi Jie Du Formula(YQJDF)combined with salinomycin(SAL)on nasopharyngeal carcinoma stem cells(NPC-SCs)and investigate the underlying molecular mechanisms.Methods Cell counting meth...Objective To assess the effects of Yi Qi Jie Du Formula(YQJDF)combined with salinomycin(SAL)on nasopharyngeal carcinoma stem cells(NPC-SCs)and investigate the underlying molecular mechanisms.Methods Cell counting methods,the CCK-8 assay,transwell migration assay and JC-1 staining,were used to observe the effects of the combination on the proliferation,migration and apoptosis of NPC stem cells,respectively.Western blot was used to detect the levels of protein in NPC-SCs.Results YQJDF combined with SAL had a synergistic effect on the inhibition of proliferation and migration and induction of NPCSC apoptosis.Mechanistically,YQJDF combined with SAL synergistically upregulated the levels of apoptotic proteins,including cleaved Caspase-3,cleaved Caspase-7 and cleaved Caspase-9.Moreover,YQJDF combined with SAL synergistically decreased the levels of CD44,p-c-Src,Ras,p-PKCδ,p-MEK,p-c-Raf,p-ERK1/2 and p-AKT proteins.Conclusions The combination of YQJDF and SAL has a synergistic effect on the inhibition of NPC-SC proliferation and migration and induction of apoptosis,which may be closely related to the downregulation of the CD44/Ras signaling pathway.展开更多
Objectives In this work,we explore the effect of atorvastatin on myocardial apoptosis and caspase-8 acti- vation after coronary microembolization(CME) in rats. Methods Fifty rats were randomly divided into five groups...Objectives In this work,we explore the effect of atorvastatin on myocardial apoptosis and caspase-8 acti- vation after coronary microembolization(CME) in rats. Methods Fifty rats were randomly divided into five groups; the coronary microembolization(CME) group,the sham-operated (sham) control group,the gastric lavage control group, the atorvastatin lavage group,and the caspasse-8 inhibitor (N-acetyl-Ile-Glu-Thr-Asp-CHO,abbreviated as CHO) group,with 10 rats for each group.A microembolization ball was injected through the left ventricle for constructing the CME model.Animals in the sham control group were given an injection of physiological saline instead of the microembolization ball.Seven days before the operation,the atorvastatin group underwent gastric lavage with 20 mg/kg of atorvastatin once a day.Gastric lavage control animals underwent gastric lavage with an equivalent dose of physiological saline instead of the atorvastatin.Animals in the CHO group were given an intraperitoneal injection of 10 mg/kg of CHO 30 min before the operation.Six hours after the operation,cardiac ultrasonic detection was conducted on each group to measure the cardiac function indexes.TUNEL(Terminal-deoxynucleoitidyl transferase mediated dUTP nick end labeling) assays were used to measure myocardial apoptosis,and western blots were used to quantify the expression levels of activated caspase-3 and -8.Results(1) The echocardiographic parameters showed that,compared to the sham control animals,the left ventricular ejection fraction(LVEF) of the CME group was significantly decreased(P【0.05).In addition, cardiac sonography revealed a decrease in the left ventricular shortening fraction(FS) and cardiac output(CO), but an increase in the left ventricular end-diastolic dimension (LVEDd).Compared to the CME group,the atorvastatin and CHO groups exhibited significantly improved cardiac function (P【0.05).(2) When compared with the sham control,the myocardical apoptotic rate of the CME group,as well as the levels of activated caspase-3 and-8,increased significantly (P【0.05).The myocardial apoptotic rate,as well as the levels of activated caspase-3 and caspase-8 in the atorvastatin and CHO groups,decreased significandy(P【0.05) in comparison to the CME group.Conclusions The atorvastatin pretreatment clearly suppressed post-CME myocardial apoptosis and improved cardiac function.The most likely mechanism for these effects is the blockade of the myocardial death receptor -mediated apoptosis pathway.展开更多
Ligands for macrophage scavenger receptors are reported to induce a wide range of host cell responses, including the production of inflammatory cytokines;however, the underlying mechanisms have not yet been fully unde...Ligands for macrophage scavenger receptors are reported to induce a wide range of host cell responses, including the production of inflammatory cytokines;however, the underlying mechanisms have not yet been fully understood and which remain obscure. In this study, we have examined the effect of maleylated bovine serum albumin (maleylated-BSA), a well-known ligand of the scavenger receptor, on the murine macrophage cell line RAW264.7. Maleylated-BSA strongly induced the production of tumor necrosis factor-α (TNF-α) and induced phosphorylation of extracellular signal-regulated kinase (ERK) and NF-kB p65. We also observed that maleylated-BSA-induced TNF-α production was blocked by the ERK inhibitor U0126. Together, these data demonstrates that maleylated-BSA- induced production of TNF-α requires the ERK/NF-κB signaling cascade in murine RAW- 264.7 macrophages.展开更多
Objective:To investigate the effect of Bushen Antai Granule on the mRNA and protein expression of Ras protein/mitogen activated protein kinase mediated by vascular endothelial growth factor receptor 2 with small inter...Objective:To investigate the effect of Bushen Antai Granule on the mRNA and protein expression of Ras protein/mitogen activated protein kinase mediated by vascular endothelial growth factor receptor 2 with small interference RNA interference.Methods:Method to construct the placenta microvascular endothelial cells,and the preparation of kidney fetus granule drug-containing serum,select the best drug-containing serum concentration,it can be divided into normal group,the serum siRNA-NC normal serum group,drug serum,siRNA normal serum group,siRNA drug serum group,using real-time fluorescent quantitative PCR,Western blotting,immunofluorescence test respectively the RAS/MAPK mRNA and protein expression.Results:Results there was no significant difference in Ras and MAPK mRNA and protein expression between the normal group and the negative control group(P>0.05).The mRNA and protein expressions of Ras and MAPK in the drug serum group were significantly higher than those in the normal serum group(P<0.01).Ras and MAPK mRNA and protein expression were significantly decreased in siRNA1 normal serum group compared with normal serum group(P<0.01).Ras,MAPK mRNA and protein expression in siRNA1 drug serum group were significantly different from that in siRNA1 normal serum group(P<0.01).Conclusion:Conclusion The therapeutic effect of Bushen Antai Granule on recurrent abortion may be realized by upregulation of RAS/MAPK mRNA and protein expression.展开更多
基金funded by the National Natural Science Foundation for Young Scholars of China,No.81101362 and 81401784the Key Project of National Natural Science Foundation of China,No.81330042
文摘An increasing number of studies report that the Ras/Raf/extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway has a death-promoting apoptotic function in neural cells. We hypothesized that the Ras/Raf/ERK1/2 signaling pathway may be abnormally regulated in rat injured spinal cord models. The weight drop method was used to establish rat spinal cord injury at T9. Western blot analysis and immunohistochemical staining revealed Ras expression was dramatically elevated, and the phosphorylations of A-Raf, B-Raf and C-Raf were all upregulated in the injured spinal cord. Both mitogen-activated protein kinase kinase 1/2 and ERK1/2, which belong to the Ras/Raf signaling kinases, were upregulated. These results indicate that Ras/Raf/ ERK1/2 signaling may be upregulated in injured spinal cord and are involved in recovery after spinal cord injury.
基金supported by the National Natural Science Foundation of China(Grant Nos.82073934,81872937,and 81673513).
文摘The current study aimed to assess the effect of timosaponin AⅢ(T-AⅢ)on drug-metabolizing enzymes during anticancer therapy.The in vivo experiments were conducted on nude and ICR mice.Following a 24-day administration of T-AⅢ,the nude mice exhibited an induction of CYP2B10,MDR1,and CYP3A11 expression in the liver tissues.In the ICR mice,the expression levels of CYP2B10 and MDR1 increased after a three-day T-AⅢ administration.The in vitro assessments with HepG2 cells revealed that T-AⅢ induced the expression of CYP2B6,MDR1,and CYP3A4,along with constitutive androstane receptor(CAR)activation.Treatment with CAR siRNA reversed the T-AⅢ-induced increases in CYP2B6 and CYP3A4 expression.Furthermore,other CAR target genes also showed a significant increase in the expression.The up-regulation of murine CAR was observed in the liver tissues of both nude and ICR mice.Subsequent findings demonstrated that T-AⅢ activated CAR by inhibiting ERK1/2 phosphorylation,with this effect being partially reversed by the ERK activator t-BHQ.Inhibition of the ERK1/2 signaling pathway was also observed in vivo.Additionally,T-AⅢ inhibited the phosphorylation of EGFR at Tyr1173 and Tyr845,and suppressed EGF-induced phosphorylation of EGFR,ERK,and CAR.In the nude mice,T-AⅢ also inhibited EGFR phosphorylation.These results collectively indicate that T-AⅢ is a novel CAR activator through inhibition of the EGFR pathway.
基金Liaoning Natural Science Foundation(20180530033)Open Fund of Key Laboratory of Ministry of Education for TCM Viscera-State Theory and Applications,Liaoning University of Traditional Chinese Medicine。
文摘[Objectives]To explore the neuroprotective effects and mechanism of Longan Aril(LA)effective parts on PC12 cells injured by H2O2.[Methods]The neuroprotective effects of LA were evaluated by the cell viability,SOD and MDA content,apoptosis assay and relative protein expression of Aβand p-Tau.The neuroprotective mechanism of LA was studied by using metabolomics and network pharmacology,and the expressions of RAS/MEK/ERK signaling pathway-related proteins were detected by western blotting.[Results]LA could improve the cell survival rate and SOD content,and reduce apoptosis and expression of Aβand p-tau.Inhibition of RAS/MEK/ERK signaling pathway is a possible mechanism of LA neuroprotective effects.[Conclusions]LA has a neuroprotective effects in vitro and be likely to inhibit the process of AD by inhibition of RAS/MEK/ERK signalling pathway.
文摘BACKGROUND Insomnia is a disease where individuals cannot maintain a steady and stable sleep state or fail to fall asleep.Western medicine mainly uses sedatives and hypnotic drugs to treat insomnia,and long-term use is prone to drug resistance and other adverse reactions.Acupuncture has a good curative effect and unique advantages in the treatment of insomnia.AIM To explore the molecular mechanism of acupuncture at Back-Shu point for the treatment of insomnia.METHODS We first prepared a rat model of insomnia,and then carried out acupuncture for 7 consecutive days.After treatment,the sleep time and general behavior of the rats were determined.The Morris water maze test was used to assess the learning ability and spatial memory ability of the rats.The expression levels of inflammatory cytokines in serum and the hippocampus were detected by ELISA.qRTPCR was used to detect the mRNA expression changes in the ERK/NF-κB signaling pathway.Western blot and immunohistochemistry were carried out to evaluate the protein expression levels of RAF-1,MEK-2,ERK1/2 and NF-κB.RESULTS Acupuncture can prolong sleep duration,and improve mental state,activity,diet volume,learning ability and spatial memory.In addition,acupuncture increased the release of 1L-1β,1L-6 and TNF-αin serum and the hippocampus and inhibited the mRNA and protein expression of the ERK/NF-κB signaling pathway.CONCLUSION These findings suggest that acupuncture at Back-Shu point can inhibit the ERK/NF-κB signaling pathway and treat insomnia by increasing the release of inflammatory cytokines in the hippocampus.
基金Supported by Natural Science Fund of Hubei Province(201918283)
文摘Objective:To study the involvement of MAPK MEK/ERK signaling transduction pathway in the apoptosis process of SW620 tumor cell line and the inhibition effect of resveratrol.Methods:SW620 cell lines were divided into 5 groups,namely,control group.PD98059 group,low-dose resveratrol group,mid-dose resveratrol group and high-dose resveratrol group.The inhibition rate of cell proliferation was detected by MTT method.The expression of apoptotic molecules and MEK/ERK signaling pathway related proteins were assayed by realtime PCR and Western blotting.Results:Compared with control group,the proliferation of cells treated with resveratrol was significantly inhibited.In the case of apoptotic molecules,the expression of Bax,Caspase 3 and Caspase 9 was increased significantly while the expression of anti-apoptotic molecule Bcl2 was decreased significantly in resveratrol groups with a dosedependent manner.In the case of molecules in MEK/ERK signaling pathway,the expression of Ras,Raf,MEK and ERKl/2 was decreased significantly in resveratrol groups with a dose-dependent manner.Conclusions:PD98059 and resveratrol can effectively inhibit the proliferation of SW620 through inhibiting the MEK/ERK signaling pathway.
基金We thank for the funding support from the National Natural Science Foundation of China(No.81874408,No.81973914 and No.81573721)the Natural Science Foundation of Hunan Province,China(No.2019JJ40216)Study Fundation of Hunan Provincial Education Department(No.19B439).
文摘Objective To assess the effects of Yi Qi Jie Du Formula(YQJDF)combined with salinomycin(SAL)on nasopharyngeal carcinoma stem cells(NPC-SCs)and investigate the underlying molecular mechanisms.Methods Cell counting methods,the CCK-8 assay,transwell migration assay and JC-1 staining,were used to observe the effects of the combination on the proliferation,migration and apoptosis of NPC stem cells,respectively.Western blot was used to detect the levels of protein in NPC-SCs.Results YQJDF combined with SAL had a synergistic effect on the inhibition of proliferation and migration and induction of NPCSC apoptosis.Mechanistically,YQJDF combined with SAL synergistically upregulated the levels of apoptotic proteins,including cleaved Caspase-3,cleaved Caspase-7 and cleaved Caspase-9.Moreover,YQJDF combined with SAL synergistically decreased the levels of CD44,p-c-Src,Ras,p-PKCδ,p-MEK,p-c-Raf,p-ERK1/2 and p-AKT proteins.Conclusions The combination of YQJDF and SAL has a synergistic effect on the inhibition of NPC-SC proliferation and migration and induction of apoptosis,which may be closely related to the downregulation of the CD44/Ras signaling pathway.
文摘Objectives In this work,we explore the effect of atorvastatin on myocardial apoptosis and caspase-8 acti- vation after coronary microembolization(CME) in rats. Methods Fifty rats were randomly divided into five groups; the coronary microembolization(CME) group,the sham-operated (sham) control group,the gastric lavage control group, the atorvastatin lavage group,and the caspasse-8 inhibitor (N-acetyl-Ile-Glu-Thr-Asp-CHO,abbreviated as CHO) group,with 10 rats for each group.A microembolization ball was injected through the left ventricle for constructing the CME model.Animals in the sham control group were given an injection of physiological saline instead of the microembolization ball.Seven days before the operation,the atorvastatin group underwent gastric lavage with 20 mg/kg of atorvastatin once a day.Gastric lavage control animals underwent gastric lavage with an equivalent dose of physiological saline instead of the atorvastatin.Animals in the CHO group were given an intraperitoneal injection of 10 mg/kg of CHO 30 min before the operation.Six hours after the operation,cardiac ultrasonic detection was conducted on each group to measure the cardiac function indexes.TUNEL(Terminal-deoxynucleoitidyl transferase mediated dUTP nick end labeling) assays were used to measure myocardial apoptosis,and western blots were used to quantify the expression levels of activated caspase-3 and -8.Results(1) The echocardiographic parameters showed that,compared to the sham control animals,the left ventricular ejection fraction(LVEF) of the CME group was significantly decreased(P【0.05).In addition, cardiac sonography revealed a decrease in the left ventricular shortening fraction(FS) and cardiac output(CO), but an increase in the left ventricular end-diastolic dimension (LVEDd).Compared to the CME group,the atorvastatin and CHO groups exhibited significantly improved cardiac function (P【0.05).(2) When compared with the sham control,the myocardical apoptotic rate of the CME group,as well as the levels of activated caspase-3 and-8,increased significantly (P【0.05).The myocardial apoptotic rate,as well as the levels of activated caspase-3 and caspase-8 in the atorvastatin and CHO groups,decreased significandy(P【0.05) in comparison to the CME group.Conclusions The atorvastatin pretreatment clearly suppressed post-CME myocardial apoptosis and improved cardiac function.The most likely mechanism for these effects is the blockade of the myocardial death receptor -mediated apoptosis pathway.
文摘Ligands for macrophage scavenger receptors are reported to induce a wide range of host cell responses, including the production of inflammatory cytokines;however, the underlying mechanisms have not yet been fully understood and which remain obscure. In this study, we have examined the effect of maleylated bovine serum albumin (maleylated-BSA), a well-known ligand of the scavenger receptor, on the murine macrophage cell line RAW264.7. Maleylated-BSA strongly induced the production of tumor necrosis factor-α (TNF-α) and induced phosphorylation of extracellular signal-regulated kinase (ERK) and NF-kB p65. We also observed that maleylated-BSA-induced TNF-α production was blocked by the ERK inhibitor U0126. Together, these data demonstrates that maleylated-BSA- induced production of TNF-α requires the ERK/NF-κB signaling cascade in murine RAW- 264.7 macrophages.
基金National Natural Science Foundation of China(No.81574017)。
文摘Objective:To investigate the effect of Bushen Antai Granule on the mRNA and protein expression of Ras protein/mitogen activated protein kinase mediated by vascular endothelial growth factor receptor 2 with small interference RNA interference.Methods:Method to construct the placenta microvascular endothelial cells,and the preparation of kidney fetus granule drug-containing serum,select the best drug-containing serum concentration,it can be divided into normal group,the serum siRNA-NC normal serum group,drug serum,siRNA normal serum group,siRNA drug serum group,using real-time fluorescent quantitative PCR,Western blotting,immunofluorescence test respectively the RAS/MAPK mRNA and protein expression.Results:Results there was no significant difference in Ras and MAPK mRNA and protein expression between the normal group and the negative control group(P>0.05).The mRNA and protein expressions of Ras and MAPK in the drug serum group were significantly higher than those in the normal serum group(P<0.01).Ras and MAPK mRNA and protein expression were significantly decreased in siRNA1 normal serum group compared with normal serum group(P<0.01).Ras,MAPK mRNA and protein expression in siRNA1 drug serum group were significantly different from that in siRNA1 normal serum group(P<0.01).Conclusion:Conclusion The therapeutic effect of Bushen Antai Granule on recurrent abortion may be realized by upregulation of RAS/MAPK mRNA and protein expression.