H-Ras is well known as one of the essential components of Ras/Raf/MEK/ERK cascade, which is a critical prosurvival signaling mechanism in most eukaryotic cells. Ras targets Raf/MEK/ERK cascade by integrating and trans...H-Ras is well known as one of the essential components of Ras/Raf/MEK/ERK cascade, which is a critical prosurvival signaling mechanism in most eukaryotic cells. Ras targets Raf/MEK/ERK cascade by integrating and transmitting extracellular signals from growth factor receptors to Raf, leading to the propagation of signals to modulate a serious of cellular survival events. Apoptosis signal-regulating kinasel (ASK1) serves as a general mediator of cell death because it is responsive to a variety of death signals. In this study, we found that H-Ras interacted with ASK1 to cause the inhibition of both ASK1 activity and ASK1-induced apoptosis in vivo, which was reversed only partially by addition of RafS621A, an antagonist of Raf, whereas MEK inhibitor, PD98059, and PI3K inhibitor, LY294002, did not disturb the inhibitory effect of H-Ras on ASK-1-induced apoptosis. Furthermore, by means of immunoprecipitate and kinase assays, we demonstrated that the interaction between H-Ras and ASK1 as well as the inhibition of ASK1 activity were dependent on the binding activity of H-Ras. These results suggest that a novel mechanism may be involved in H-Rasmediated cell survival in addition to the well established MEK/ERK and PI3K/Akt kinase-dependent enhancement of cell survival.展开更多
Objective： To study the expression level of TRF1 （telomeric repeat binding factor 1） protein in human acute leukemia and relationship between expression level of TRF1 protein and telomerase, Methods： A quantitativ...Objective： To study the expression level of TRF1 （telomeric repeat binding factor 1） protein in human acute leukemia and relationship between expression level of TRF1 protein and telomerase, Methods： A quantitative Western±Blot technique was developed using anti±TRF1^33±277 monoclonal antibody and GST±TRFI purity protein as a standard to further determine the expression level of TRF1 protein in total proteins extracted from clinical specimens. Results： Bone marrow tissues of 20 acute leukemia patients were studied, 11 healthy donors＇ bone marrows were taken as a control. The expression level of TRF1 protein was significantly higher （P〈0.01） in normal bone marrow （（2.2174±0.462） μg/μl） than that of acute leukemia patients （（0.7544±0.343） μg/μl）, But there was no remarkable difference between ALL and ANLL patients （（0.6184±0.285） μg/μl vs （0.8454±0.359） μg/μl, P〉0.05）. After chemotherapy, TRFI expression level of patients with complete remission elevated （（0.7724±0.307）/μg/μl vs （1.6834±0,344）μg/μl, P〈0.01 ）, but lower than that of normal （（2.2174±0.462）/μg/μl, P〈0.01）. There was no significantly difference after chemotherapy （（0.7264±0.411） μg/μl vs （0.895±0.339） μg/μl,p〉0.05）. TRF1 expression level of patients with complete remission is higher than that of patients without complete remission （（1,683±0.344）μg/μl vs （0.895±0.339）μg/μl P〈0.01）. All samples were determined for telomerase activity. It was confirmed that the activity of telomerase in normal bone marrow was lower than that of acute leukemia patients （（0.125±0.078） μg/μl vs （0.765±0.284）μg/μl, P〈0.01）. There was no significant difference of expression level ofTRF I protein between ALL and ANLL patients （（0.897±0.290） μg/μl vs （0.677±0.268） μg/μl, P〉0.05）. After chemotherapy, telomerase activity of patients with complete remission decreased （（0.393±0.125） μg/μl）, but was still higher than that of normal （（0.125±0.078） μg/μl, P〈0.01）. Conclusion： The expression level of TRF1 protein has correlativity to the activity of telomerase （P〈0.001）.展开更多
Objective This study aimed to investigate the effects of caprylic acid(C8:0)on lipid metabolism and inflammation,and examine the mechanisms underlying these effects in mice and cells.Methods Fifty-six 6-week-old male ...Objective This study aimed to investigate the effects of caprylic acid(C8:0)on lipid metabolism and inflammation,and examine the mechanisms underlying these effects in mice and cells.Methods Fifty-six 6-week-old male C57BL/6J mice were randomly allocated to four groups fed a highfat diet(HFD)without or with 2%C8:0,palmitic acid(C16:0)or eicosapentaenoic acid(EPA).RAW246.7 cells were randomly divided into five groups:normal,lipopolysaccharide(LPS),LPS+C8:0,LPS+EPA and LPS+cAMP.The serum lipid profiles,inflammatory biomolecules,and ABCA1 and JAK2/STAT3 mRNA and protein expression were measured.Results C8:0 decreased TC and LDL-C,and increased the HDL-C/LDL-C ratio after injection of LPS.Without LPS,it decreased TC in mice(P<0.05).Moreover,C8:0 decreased the inflammatory response after LPS treatment in both mice and cells(P<0.05).Mechanistic investigations in C57BL/6J mouse aortas after injection of LPS indicated that C8:0 resulted in higher ABCA1 and JAK2/STAT3 expression than that with HFD,C16:0 and EPA,and resulted in lower TNF-α,NF-κB mRNA expression than that with HFD(P<0.05).In RAW 264.7 cells,C8:0 resulted in lower expression of pNF-κBP65 than that in the LPS group,and higher protein expression of ABCA1,p-JAK2 and p-STAT3 than that in the LPS and LPS+cAMP groups(P<0.05).Conclusion Our studies demonstrated that C8:0 may play an important role in lipid metabolism and the inflammatory response,and the mechanism may be associated with ABCA1 and the p-JAK2/p-STAT3 signaling pathway.展开更多
Two different types of 1-[2-(hydroxyethoxy)methyl]-6-naphthylmethylthymines have been designed, synthesized and evaluated for their anti-HIV-1 activities in different cells lines. The binding free energy (DG) includin...Two different types of 1-[2-(hydroxyethoxy)methyl]-6-naphthylmethylthymines have been designed, synthesized and evaluated for their anti-HIV-1 activities in different cells lines. The binding free energy (DG) including steric and electrostatic between the two different ligands and reverse transcriptase Non-Nucleoside Binding Pocket (NNBP) have been docked and calculated to evaluate their accommodation circumstance on a SGI work station. The DG and anti-HIV-1 activity has been correlated in order to guide further drug design, which showed that the steric binding effect dominated in the whole binding action between the compounds and reverse transcriptase (RT). The results showed that more negative DG led to higher activity of compounds.展开更多
小整合频率1(petite integration frequency 1,PIF1)解旋酶广泛存在于生物体内,在核酸的代谢过程中发挥着重要作用。近年来,人们已经报道了多种PIF1解旋酶的生化活性及三维结构,但对极端环境下细菌的PIF1解旋酶的报道仍较少。本文利用...小整合频率1(petite integration frequency 1,PIF1)解旋酶广泛存在于生物体内,在核酸的代谢过程中发挥着重要作用。近年来,人们已经报道了多种PIF1解旋酶的生化活性及三维结构,但对极端环境下细菌的PIF1解旋酶的报道仍较少。本文利用多种生物化学与生物物理学技术,对黄石热脱硫弧菌PIF1(Ty.PIF1)解旋酶进行了多方面研究。通过原核表达纯化系统,获得了纯度90%以上,均一性好的Ty.PIF1蛋白。Ty.PIF1在溶液中为单体,分子量约为60 kD。Ty.PIF1具有很高的热稳定性,在65℃以下时,二级结构保持稳定,大于70℃时,二级结构才会发生改变。Ty.PIF1在体外最适解旋温度为45℃,并非黄石热脱硫弧菌生存的最适温度,预示着Ty.PIF1在体内发挥活性时,可能需要其他辅助因子的参与。Ty.PIF1的酶活力温度范围较宽,在20~55℃均具有解旋活性,在55℃能解旋预示了Ty.PIF1具有耐热特性。Ty.PIF1偏向于同含有单链的底物结合,但对单链长度有一定要求,其长度至少大于4 nt;Ty.PIF1也会较好地结合无单链尾链的G4结构,说明Ty.PIF1可能有专门结合G4结构的区域。Ty.PIF1能解开一系列带有5′-单链尾链的类似于复制中间体的底物,且对底物结构有一定的偏好性;Ty.PIF1也可以解开含有G4结构的底物,DNA-RNA杂交链、RNA-loop结构,预示着Ty.PIF1在生物体内有着多种生物学功能。Ty.PIF1解旋带有不同长度5′-单链尾链的双链底物时,尾链长度越长,解旋速率越快,预示着Ty.PIF1可能与Sc.PIF1一样有着较低的解旋持续性。本文将Ty.PIF1的生化活性与其它物种的PIF1解旋酶进行了比较,找出了其中的共性与差异,加深了人们对嗜热菌PIF1解旋酶的认识,为今后研究其它极端环境微生物的PIF1解旋酶提供了一些思路。展开更多
文摘H-Ras is well known as one of the essential components of Ras/Raf/MEK/ERK cascade, which is a critical prosurvival signaling mechanism in most eukaryotic cells. Ras targets Raf/MEK/ERK cascade by integrating and transmitting extracellular signals from growth factor receptors to Raf, leading to the propagation of signals to modulate a serious of cellular survival events. Apoptosis signal-regulating kinasel (ASK1) serves as a general mediator of cell death because it is responsive to a variety of death signals. In this study, we found that H-Ras interacted with ASK1 to cause the inhibition of both ASK1 activity and ASK1-induced apoptosis in vivo, which was reversed only partially by addition of RafS621A, an antagonist of Raf, whereas MEK inhibitor, PD98059, and PI3K inhibitor, LY294002, did not disturb the inhibitory effect of H-Ras on ASK-1-induced apoptosis. Furthermore, by means of immunoprecipitate and kinase assays, we demonstrated that the interaction between H-Ras and ASK1 as well as the inhibition of ASK1 activity were dependent on the binding activity of H-Ras. These results suggest that a novel mechanism may be involved in H-Rasmediated cell survival in addition to the well established MEK/ERK and PI3K/Akt kinase-dependent enhancement of cell survival.
文摘Objective： To study the expression level of TRF1 （telomeric repeat binding factor 1） protein in human acute leukemia and relationship between expression level of TRF1 protein and telomerase, Methods： A quantitative Western±Blot technique was developed using anti±TRF1^33±277 monoclonal antibody and GST±TRFI purity protein as a standard to further determine the expression level of TRF1 protein in total proteins extracted from clinical specimens. Results： Bone marrow tissues of 20 acute leukemia patients were studied, 11 healthy donors＇ bone marrows were taken as a control. The expression level of TRF1 protein was significantly higher （P〈0.01） in normal bone marrow （（2.2174±0.462） μg/μl） than that of acute leukemia patients （（0.7544±0.343） μg/μl）, But there was no remarkable difference between ALL and ANLL patients （（0.6184±0.285） μg/μl vs （0.8454±0.359） μg/μl, P〉0.05）. After chemotherapy, TRFI expression level of patients with complete remission elevated （（0.7724±0.307）/μg/μl vs （1.6834±0,344）μg/μl, P〈0.01 ）, but lower than that of normal （（2.2174±0.462）/μg/μl, P〈0.01）. There was no significantly difference after chemotherapy （（0.7264±0.411） μg/μl vs （0.895±0.339） μg/μl,p〉0.05）. TRF1 expression level of patients with complete remission is higher than that of patients without complete remission （（1,683±0.344）μg/μl vs （0.895±0.339）μg/μl P〈0.01）. All samples were determined for telomerase activity. It was confirmed that the activity of telomerase in normal bone marrow was lower than that of acute leukemia patients （（0.125±0.078） μg/μl vs （0.765±0.284）μg/μl, P〈0.01）. There was no significant difference of expression level ofTRF I protein between ALL and ANLL patients （（0.897±0.290） μg/μl vs （0.677±0.268） μg/μl, P〉0.05）. After chemotherapy, telomerase activity of patients with complete remission decreased （（0.393±0.125） μg/μl）, but was still higher than that of normal （（0.125±0.078） μg/μl, P〈0.01）. Conclusion： The expression level of TRF1 protein has correlativity to the activity of telomerase （P〈0.001）.
基金supported by the National Natural Science Fund of China[no.81703204].
文摘Objective This study aimed to investigate the effects of caprylic acid(C8:0)on lipid metabolism and inflammation,and examine the mechanisms underlying these effects in mice and cells.Methods Fifty-six 6-week-old male C57BL/6J mice were randomly allocated to four groups fed a highfat diet(HFD)without or with 2%C8:0,palmitic acid(C16:0)or eicosapentaenoic acid(EPA).RAW246.7 cells were randomly divided into five groups:normal,lipopolysaccharide(LPS),LPS+C8:0,LPS+EPA and LPS+cAMP.The serum lipid profiles,inflammatory biomolecules,and ABCA1 and JAK2/STAT3 mRNA and protein expression were measured.Results C8:0 decreased TC and LDL-C,and increased the HDL-C/LDL-C ratio after injection of LPS.Without LPS,it decreased TC in mice(P<0.05).Moreover,C8:0 decreased the inflammatory response after LPS treatment in both mice and cells(P<0.05).Mechanistic investigations in C57BL/6J mouse aortas after injection of LPS indicated that C8:0 resulted in higher ABCA1 and JAK2/STAT3 expression than that with HFD,C16:0 and EPA,and resulted in lower TNF-α,NF-κB mRNA expression than that with HFD(P<0.05).In RAW 264.7 cells,C8:0 resulted in lower expression of pNF-κBP65 than that in the LPS group,and higher protein expression of ABCA1,p-JAK2 and p-STAT3 than that in the LPS and LPS+cAMP groups(P<0.05).Conclusion Our studies demonstrated that C8:0 may play an important role in lipid metabolism and the inflammatory response,and the mechanism may be associated with ABCA1 and the p-JAK2/p-STAT3 signaling pathway.
文摘Two different types of 1-[2-(hydroxyethoxy)methyl]-6-naphthylmethylthymines have been designed, synthesized and evaluated for their anti-HIV-1 activities in different cells lines. The binding free energy (DG) including steric and electrostatic between the two different ligands and reverse transcriptase Non-Nucleoside Binding Pocket (NNBP) have been docked and calculated to evaluate their accommodation circumstance on a SGI work station. The DG and anti-HIV-1 activity has been correlated in order to guide further drug design, which showed that the steric binding effect dominated in the whole binding action between the compounds and reverse transcriptase (RT). The results showed that more negative DG led to higher activity of compounds.
