Background The present study aimed to investigate the detailed mode and specific sites for their binding as well as the functional relevance of this binding in the phenotypic proliferation of vascular smooth muscle ce...Background The present study aimed to investigate the detailed mode and specific sites for their binding as well as the functional relevance of this binding in the phenotypic proliferation of vascular smooth muscle cells(SMCs). Methods CREG knocked-down SMCs were employed to evaluate the biological activity of wtCREG and mCREG.Expressions of SMC differentiation markers SM myosin heavy chain(SM-MHC),SM-actin,heavy caldesmon and myocardin were determined by Western blotting using specific antibodies. Cellular growth of SMCs was assessed by bromide dewuridine (BrdU) incorporation and cell cycle analysis on fluorescence-activated cell sorting(FACS).A solid-phase binding assay was used to study the binding of CREG to extracellular domains of M6P/IGF2R.The cellular co-localization of the two recombinant CREGs with M6P/IGF2R was detected on SMC surface by immunoprecipitation and immunofluorescence analysis.Results The molecular weight of wtCREG was around 30 kD while that of the mCREG was~25 kD.Treatment of wtCREG with PNGase F reduced its molecular weight from~30 kD to~25 kD,whereas PNGase F treatment had no effect on the molecular weight of mCREG.Both wtCREG and mCREG proteins enhanced SMC differentiation,inhibited BrdU incorporation,and arrested cell cycle progression when added to the culture medium.In CREG knocked-down SMCs,the amount of CREG detected by immunoblotting in M6P/IGF2R immunoprecipitates was significantly reduced when compared to normal cells.Both recombinant CREGs co-immunoprecipitated with M6P/IGF2R, although slightly reduced amount of the mutant CREG was detected in M6P/IGF2R immunoprecipitates.Immunostaining revealed that His-tagged CREGs co-localized with IGF2R on the cell surface in a glycosylation-independent manner.In vitro binding assay showed that CREGs bound to M6P/ IGF2R extracellular domains 7-10 and 11-13 in a glycosylation -dependent and -independent manner,respectively.Further blocking experiments using soluble M6P/IGF2R fragments and M6P/IGF2R neutralizing antibody indicated that the biological activities of recombinant CREGs in SMC growth and the up-regulation of SMC differentiation markers were all abolished by treatment with the M6P/IGF2R neutralizing antibody. However,although the growth inhibitory effect of wtCREG was nearly abolished by D7-10 or D11-13,the effect of mCREG was only reversed by Dll-13,indicating that the binding to domains 11-13 is required for CREG to modulate the proliferation of SMCs.Conclusions These data suggest that solubleCREG proteins can exert their biological function via binding to the extracellular domains 7-10 and 11-13 of cell surface M6P/IGF2R in both a glycosylation-dependent and -independent manner.展开更多
Objectives Epidermal growth factor receptor (EGFR)is a receptor protein tyrosine kinase and plays a critical role in the development and function of the heart.Previous studies have demonstrated that EGFR is involved...Objectives Epidermal growth factor receptor (EGFR)is a receptor protein tyrosine kinase and plays a critical role in the development and function of the heart.Previous studies have demonstrated that EGFR is involved in regulating electrical excitability of the heart.The present study was designed to investigate whether EGFR activation would mediate myocardial arrhythmias induced by ischemia/reperfu- sion in anaesthetized rats.Methods and results Myocardial ischemia/reperfusion arrhythmias were induced by 10 min ligation of the left anterior descending coronary artery,followed by a 30 min reperfusion in anaesthetized rats.Incidence and severity of cardiac arrhythmias were significantly reduced by pretreatment with the EGFR kinase inhibitor AG556.Phosphorylation level of myocardial EGFR was increased during ischemia and at early reperfusion.Intramyocardial transfection of EGFR siRNA reduced EGFR mRNA and protein,and decreased the incidence of ventricular fibrillation induced by reperfusion.Interestingly,tyrosine phosphorylation levels of cardiac Na<sup>+</sup> channel(I<sub>Na</sub>) and L-type Ca<sup>2+</sup> channel(I<sub>Ca.l</sub>) were significantly increased at corresponding time points to the alteration of phosphorylated EGFR level during reperfusion.AG556 pretreatment countered the increased tyrosine phosphorylation level of Na<sup>+</sup> and L-type Ca<sup>2+</sup> channels induced by reperfusion.No significant alteration was observed in tyrosine phosphorylation levels of cardiac Kv4.2 and Kir2.1 channels during the cardiac ischemia/reperfusion. Conclusions These results demonstrate for the first time that EGFR plays an important role in the genesis of myocardial ischemia/reperfusion arrhythmias,which is likely mediated at least in part by enhancing tyrosine phosphorylation of cardiac Na<sup>+</sup> and L-type Ca<sup>2+</sup> channels.展开更多
With the support of the National Natural Science Foundation of China and the Ministry of Science and Technology of China,the research teams led by Prof.Gao Hua(高华)from Tongji University,and Prof.Filippo Giancotti at...With the support of the National Natural Science Foundation of China and the Ministry of Science and Technology of China,the research teams led by Prof.Gao Hua(高华)from Tongji University,and Prof.Filippo Giancotti at Memorial Sloan Kettering Cancer Center,reported recently on the mechanism of multiorgan site metastatic creactivation,which was published in Cell(2016,166:47—62).展开更多
Abstract Objective To investigate the effects of combined blockade by platelet activating factor (PAF) receptor antagonist BN 52021 in combination with opiate receptor antagonist naloxone on neurologica...Abstract Objective To investigate the effects of combined blockade by platelet activating factor (PAF) receptor antagonist BN 52021 in combination with opiate receptor antagonist naloxone on neurological function and neurological tissue damage after cervical cord injury. Methods Spinal cord contusion at C 6 segment was made with Allen method in cats, which were randomly divided into four groups: saline control group; BN 52021 group; naloxone group; and combined treatment group with BN 52021 and naloxone. Alteration of cervical cord blood flow, blood barrier permeability of the spinal cord, cervical cord tissue pathology and neurological functional scores were studied after experimental cervical cord injury. Results The animals treated with BN 52021 or naloxone had significantly better functional scores than saline controls 6 weeks after injury (P<0.05). Moreover, the combined treatment showed significantly better neurologic recovery than either naloxone or BN 52021 treated animals (P<0.05). The other indexes in combined treatment animals were also superior to those in naloxone or BN 52021 treated animals. Conclusions Combined blockade by two kinds of autolesion mediator receptor can more effectively inhibit secondary damage production and development after cervical cord injury and improve neurologic function.展开更多
To study the endocytic activity of dendritic cells(DCs)by obtaining fusion protein HSP70-EGFP as exogenous antigen and loading it with DCs derived from human peripheral blood.Fusion protein HSP70-EGFP was prokaryotica...To study the endocytic activity of dendritic cells(DCs)by obtaining fusion protein HSP70-EGFP as exogenous antigen and loading it with DCs derived from human peripheral blood.Fusion protein HSP70-EGFP was prokaryotically expressed,isolated and purified.DCs were isolated and cultured from human peripheral blood.The DCs were divided into 3 groups in the endocytic experiment.There were 106 DCs in each group.Group 1 and 2 were respectively incubated for 30 min.with HSP70-EGFP and EGFP.Group 3 was incubated with HSP70 for 30 min,and then incubated for 30 min.with HSP70-EGFP.Subsequently,3 groups were placed in an incubator at 37℃for 0.5,1,2 and 24 h.Flow cytometry(FCM)was adopted to detect the amount of DCs with EGFP inside.IL-12 Eli-spot was adopted to detect the amount of DCs which secreted IL-12.There were 5 types in the experiment:LPS,inactive LPS,HSP70-EGFP,EGFP and no antigen.Fusion protein HSP70-EGFP was successfully obtained and its molecular weight was 97000.It accounted for 35.32%of the total protein.Under irradiation of an ultraviolet lamp,the protein solution sent out viridescent fluorescence.The result detected by FCM indicated that after incubation for 0.5 h at 37℃,the positive rate in group 1 was 63%,while the other 2 groups were negative.After incubation for 1,2 and 24 h at 37℃,the positive rates in the 3 groups were above 80%.The IL-12 Eli-spot examination shows that with HSP70-EGFP being loaded,the amount of DCs secreting IL-12 was 134.09±31.78/10^(5)cells,a little lower than that of DCs with LPS loaded(with the average point of 156.36±15.73).There was no significant difference between the 2 groups(P<0.01).By contrast,both of them were significantly higher than inactive LPS-(33.78±1.40)/10^(5)cells and EGFP-loaded(23.13±4.57)/105 cells DC groups in the amount of DCs secreting IL-12(P<0.01).The results suggest that receptor-mediated phagocytosis plays a main role in the preliminary stage of DCs internalizing HSP70-EGFP.With increasing incubation time,pinocytosis begins to dominate.HSP70-EGFP may promote DCs to secret cell factor IL-12.展开更多
文摘Background The present study aimed to investigate the detailed mode and specific sites for their binding as well as the functional relevance of this binding in the phenotypic proliferation of vascular smooth muscle cells(SMCs). Methods CREG knocked-down SMCs were employed to evaluate the biological activity of wtCREG and mCREG.Expressions of SMC differentiation markers SM myosin heavy chain(SM-MHC),SM-actin,heavy caldesmon and myocardin were determined by Western blotting using specific antibodies. Cellular growth of SMCs was assessed by bromide dewuridine (BrdU) incorporation and cell cycle analysis on fluorescence-activated cell sorting(FACS).A solid-phase binding assay was used to study the binding of CREG to extracellular domains of M6P/IGF2R.The cellular co-localization of the two recombinant CREGs with M6P/IGF2R was detected on SMC surface by immunoprecipitation and immunofluorescence analysis.Results The molecular weight of wtCREG was around 30 kD while that of the mCREG was~25 kD.Treatment of wtCREG with PNGase F reduced its molecular weight from~30 kD to~25 kD,whereas PNGase F treatment had no effect on the molecular weight of mCREG.Both wtCREG and mCREG proteins enhanced SMC differentiation,inhibited BrdU incorporation,and arrested cell cycle progression when added to the culture medium.In CREG knocked-down SMCs,the amount of CREG detected by immunoblotting in M6P/IGF2R immunoprecipitates was significantly reduced when compared to normal cells.Both recombinant CREGs co-immunoprecipitated with M6P/IGF2R, although slightly reduced amount of the mutant CREG was detected in M6P/IGF2R immunoprecipitates.Immunostaining revealed that His-tagged CREGs co-localized with IGF2R on the cell surface in a glycosylation-independent manner.In vitro binding assay showed that CREGs bound to M6P/ IGF2R extracellular domains 7-10 and 11-13 in a glycosylation -dependent and -independent manner,respectively.Further blocking experiments using soluble M6P/IGF2R fragments and M6P/IGF2R neutralizing antibody indicated that the biological activities of recombinant CREGs in SMC growth and the up-regulation of SMC differentiation markers were all abolished by treatment with the M6P/IGF2R neutralizing antibody. However,although the growth inhibitory effect of wtCREG was nearly abolished by D7-10 or D11-13,the effect of mCREG was only reversed by Dll-13,indicating that the binding to domains 11-13 is required for CREG to modulate the proliferation of SMCs.Conclusions These data suggest that solubleCREG proteins can exert their biological function via binding to the extracellular domains 7-10 and 11-13 of cell surface M6P/IGF2R in both a glycosylation-dependent and -independent manner.
文摘Objectives Epidermal growth factor receptor (EGFR)is a receptor protein tyrosine kinase and plays a critical role in the development and function of the heart.Previous studies have demonstrated that EGFR is involved in regulating electrical excitability of the heart.The present study was designed to investigate whether EGFR activation would mediate myocardial arrhythmias induced by ischemia/reperfu- sion in anaesthetized rats.Methods and results Myocardial ischemia/reperfusion arrhythmias were induced by 10 min ligation of the left anterior descending coronary artery,followed by a 30 min reperfusion in anaesthetized rats.Incidence and severity of cardiac arrhythmias were significantly reduced by pretreatment with the EGFR kinase inhibitor AG556.Phosphorylation level of myocardial EGFR was increased during ischemia and at early reperfusion.Intramyocardial transfection of EGFR siRNA reduced EGFR mRNA and protein,and decreased the incidence of ventricular fibrillation induced by reperfusion.Interestingly,tyrosine phosphorylation levels of cardiac Na<sup>+</sup> channel(I<sub>Na</sub>) and L-type Ca<sup>2+</sup> channel(I<sub>Ca.l</sub>) were significantly increased at corresponding time points to the alteration of phosphorylated EGFR level during reperfusion.AG556 pretreatment countered the increased tyrosine phosphorylation level of Na<sup>+</sup> and L-type Ca<sup>2+</sup> channels induced by reperfusion.No significant alteration was observed in tyrosine phosphorylation levels of cardiac Kv4.2 and Kir2.1 channels during the cardiac ischemia/reperfusion. Conclusions These results demonstrate for the first time that EGFR plays an important role in the genesis of myocardial ischemia/reperfusion arrhythmias,which is likely mediated at least in part by enhancing tyrosine phosphorylation of cardiac Na<sup>+</sup> and L-type Ca<sup>2+</sup> channels.
文摘With the support of the National Natural Science Foundation of China and the Ministry of Science and Technology of China,the research teams led by Prof.Gao Hua(高华)from Tongji University,and Prof.Filippo Giancotti at Memorial Sloan Kettering Cancer Center,reported recently on the mechanism of multiorgan site metastatic creactivation,which was published in Cell(2016,166:47—62).
文摘Abstract Objective To investigate the effects of combined blockade by platelet activating factor (PAF) receptor antagonist BN 52021 in combination with opiate receptor antagonist naloxone on neurological function and neurological tissue damage after cervical cord injury. Methods Spinal cord contusion at C 6 segment was made with Allen method in cats, which were randomly divided into four groups: saline control group; BN 52021 group; naloxone group; and combined treatment group with BN 52021 and naloxone. Alteration of cervical cord blood flow, blood barrier permeability of the spinal cord, cervical cord tissue pathology and neurological functional scores were studied after experimental cervical cord injury. Results The animals treated with BN 52021 or naloxone had significantly better functional scores than saline controls 6 weeks after injury (P<0.05). Moreover, the combined treatment showed significantly better neurologic recovery than either naloxone or BN 52021 treated animals (P<0.05). The other indexes in combined treatment animals were also superior to those in naloxone or BN 52021 treated animals. Conclusions Combined blockade by two kinds of autolesion mediator receptor can more effectively inhibit secondary damage production and development after cervical cord injury and improve neurologic function.
基金The study was supported by the General Program of National Natural Science Foundation of China(Grant No.30400167).
文摘To study the endocytic activity of dendritic cells(DCs)by obtaining fusion protein HSP70-EGFP as exogenous antigen and loading it with DCs derived from human peripheral blood.Fusion protein HSP70-EGFP was prokaryotically expressed,isolated and purified.DCs were isolated and cultured from human peripheral blood.The DCs were divided into 3 groups in the endocytic experiment.There were 106 DCs in each group.Group 1 and 2 were respectively incubated for 30 min.with HSP70-EGFP and EGFP.Group 3 was incubated with HSP70 for 30 min,and then incubated for 30 min.with HSP70-EGFP.Subsequently,3 groups were placed in an incubator at 37℃for 0.5,1,2 and 24 h.Flow cytometry(FCM)was adopted to detect the amount of DCs with EGFP inside.IL-12 Eli-spot was adopted to detect the amount of DCs which secreted IL-12.There were 5 types in the experiment:LPS,inactive LPS,HSP70-EGFP,EGFP and no antigen.Fusion protein HSP70-EGFP was successfully obtained and its molecular weight was 97000.It accounted for 35.32%of the total protein.Under irradiation of an ultraviolet lamp,the protein solution sent out viridescent fluorescence.The result detected by FCM indicated that after incubation for 0.5 h at 37℃,the positive rate in group 1 was 63%,while the other 2 groups were negative.After incubation for 1,2 and 24 h at 37℃,the positive rates in the 3 groups were above 80%.The IL-12 Eli-spot examination shows that with HSP70-EGFP being loaded,the amount of DCs secreting IL-12 was 134.09±31.78/10^(5)cells,a little lower than that of DCs with LPS loaded(with the average point of 156.36±15.73).There was no significant difference between the 2 groups(P<0.01).By contrast,both of them were significantly higher than inactive LPS-(33.78±1.40)/10^(5)cells and EGFP-loaded(23.13±4.57)/105 cells DC groups in the amount of DCs secreting IL-12(P<0.01).The results suggest that receptor-mediated phagocytosis plays a main role in the preliminary stage of DCs internalizing HSP70-EGFP.With increasing incubation time,pinocytosis begins to dominate.HSP70-EGFP may promote DCs to secret cell factor IL-12.