OBJECTIVE To investigate the protective effect against diabetes cardiovascular complications of low molecular weight fucoidan(LMWF)from L.japonica in Qindao, China. METHODS LMWF(50,100 and 200mg·kg-1·d-1)or ...OBJECTIVE To investigate the protective effect against diabetes cardiovascular complications of low molecular weight fucoidan(LMWF)from L.japonica in Qindao, China. METHODS LMWF(50,100 and 200mg·kg-1·d-1)or probucol(100mg·kg-1·d-1)were given orally to Goto-Kakizaki type 2 diabetic rats for 12 weeks.Basal blood pressure,acetylcholine-or flow-mediated relaxation of mesenteric and paw arteries,endothelium-dependent dilation of aorta,eNOS phosphorylation and NO production were measured using laser Doppler flowmetry,force myograph,HE staining,Western blot and an NO assay,respectively.The establishment of diabetic cardiomyopathy(DCM)model and were evaluated by echocardiography and isolated heart perfusion.Ventricle staining with HE or Sirius red was performed to investigate the structural changes in myocardium.Oxidative stress and apoptosis were evaluated by enzyme activities,protein expressions and cell stainings in both myocardial tissues and cultured cardiomyocytes.RESULTS In aorta,LMWF robustly ameliorated the basal hypertension and impairment of endothelium-dependent relaxation in the aorta,as well as mesenteric and paw arteries in diabetic rats.In addition,the reduction in endothelial nitric oxide synthase(eNOS)phosphorylation at Ser1177,eNOS expression and NO production due to diabetes were partially reversed by LMWF treatment.However,probucol,a lipid-modifying drug with antioxidant properties,displayed only mild effects.Moreover,LMWF induced,in a dose-dependent manner,endothelium-dependent vasodilation and eNOS phosphorylation at Ser1177 in normal aorta,and also promoted Ser1177 phosphorylation and NO synthesis in primary cultured vasoendothelial cells.On DCM,LMWF has a beneficial effect by enhancing myocardial contractility and mitigating cardiac fibrosis as well as the production of reactive oxygen species(ROS)and myocyte apoptosis in diabetic hearts.CONCLUSION These data demonstrate for the first time that fucoidan protects vasoendothelial and cardiac function against diabetic injury in type 2diabetes rats via,at least in part,preservation of eNOS function,amelioration of PKCβ-mediated oxidative stress and subsequent cardiomyocyte apoptosis.Fucoidan is therefore a potential candidate drug for protection of endothelium and heart in diabetic cardiovascular complications.展开更多
目的表达纯化2型猪链球菌(Streptococcus suis 2,SS2)低分子量酪氨酸磷酸酶(Low molecular weight protein tyrosine phosphatase,LMW-PTP),测定LMW-PTP磷酸酶活性并鉴定其酶活性位点,为后续的功能鉴定奠定基础。方法分别构建野生型LMW-...目的表达纯化2型猪链球菌(Streptococcus suis 2,SS2)低分子量酪氨酸磷酸酶(Low molecular weight protein tyrosine phosphatase,LMW-PTP),测定LMW-PTP磷酸酶活性并鉴定其酶活性位点,为后续的功能鉴定奠定基础。方法分别构建野生型LMW-PTP基因表达质粒pET28a:LMW-PTP、突变型LMW-PTP基因表达质粒pET28a:LMWPTPC33A和pET28a:LMW-PTPR39A,重组质粒转化E.coil BL21(DE3),筛选阳性转化子,通过IPTG诱导表达后经SDS-PAGE鉴定表达产物。镍柱亲和层析纯化得到重组蛋白经Western blot鉴定,野生型LMW-PTP免疫新西兰兔制备兔多克隆抗体。以对硝基苯酚二钠六水(PNPP-Na)为底物检测重组蛋白的磷酸酶活性。结果成功构建野生型LMW-PTP基因表达质粒pET28a:LMW-PTP、突变型LMW-PTP基因表达质粒pET28a:LMW-PTPC33A、pET28a:LMW-PTPR39A,在大肠杆菌中野生型和突变型LMW-PTP均以包涵体的形式存在,相对分子量为23kDa,包涵体经镍柱纯化及透析复性获得纯度较高的野生型和突变型LMW-PTP。制备得到的抗LMW-PTP的兔多克隆抗体的效价为1∶102 400,且重组蛋白均能与His-Tag单抗和兔多抗血清发生反应。对野生型蛋白进行磷酸酶活性检测显示其具有酶活性,酶活为2.1nmol/(min·μg),突变型LMW-PTPC33A、LMW-PTPR39A无磷酸酶活性。结论成功表达了具有磷酸酶活性的LMW-PTP,并鉴定出Cys33和Arg39是LMW-PTP的活性位点。为后续寻找LMW-PTP在2型猪链球菌致病过程中毒力相关的靶蛋白奠定了基础。展开更多
An improved CBB staining with higher sensitivity than that of the typical CBB staining was reported.The main improvement was using a fixing step of 25% trichloroacetic acid(TCA) before CBB staining.For most proteins s...An improved CBB staining with higher sensitivity than that of the typical CBB staining was reported.The main improvement was using a fixing step of 25% trichloroacetic acid(TCA) before CBB staining.For most proteins studied,the sensitivity of the improved CBB staining was about twice as high as that of the typical method.For basic and low molecular weight proteins such as ribosomal proteins,the sensitivity of this improved staining method was about 3.5-28 times that of the typical method.It was speculated that the improved procedure would be suitable for exact quantitative analysis of proteins fractionated by SDS-PAGE,especially for basic and low molecular weight proteins.On the other hand,this new modified method might be also applied to multidisciplinary studies,such as biological researches and nuclear sciences.展开更多
基金The project supported by National Natural Science Foundation of China(81370339)Promotion Project of Beijing Education Committee(TJSHJ201510025005)
文摘OBJECTIVE To investigate the protective effect against diabetes cardiovascular complications of low molecular weight fucoidan(LMWF)from L.japonica in Qindao, China. METHODS LMWF(50,100 and 200mg·kg-1·d-1)or probucol(100mg·kg-1·d-1)were given orally to Goto-Kakizaki type 2 diabetic rats for 12 weeks.Basal blood pressure,acetylcholine-or flow-mediated relaxation of mesenteric and paw arteries,endothelium-dependent dilation of aorta,eNOS phosphorylation and NO production were measured using laser Doppler flowmetry,force myograph,HE staining,Western blot and an NO assay,respectively.The establishment of diabetic cardiomyopathy(DCM)model and were evaluated by echocardiography and isolated heart perfusion.Ventricle staining with HE or Sirius red was performed to investigate the structural changes in myocardium.Oxidative stress and apoptosis were evaluated by enzyme activities,protein expressions and cell stainings in both myocardial tissues and cultured cardiomyocytes.RESULTS In aorta,LMWF robustly ameliorated the basal hypertension and impairment of endothelium-dependent relaxation in the aorta,as well as mesenteric and paw arteries in diabetic rats.In addition,the reduction in endothelial nitric oxide synthase(eNOS)phosphorylation at Ser1177,eNOS expression and NO production due to diabetes were partially reversed by LMWF treatment.However,probucol,a lipid-modifying drug with antioxidant properties,displayed only mild effects.Moreover,LMWF induced,in a dose-dependent manner,endothelium-dependent vasodilation and eNOS phosphorylation at Ser1177 in normal aorta,and also promoted Ser1177 phosphorylation and NO synthesis in primary cultured vasoendothelial cells.On DCM,LMWF has a beneficial effect by enhancing myocardial contractility and mitigating cardiac fibrosis as well as the production of reactive oxygen species(ROS)and myocyte apoptosis in diabetic hearts.CONCLUSION These data demonstrate for the first time that fucoidan protects vasoendothelial and cardiac function against diabetic injury in type 2diabetes rats via,at least in part,preservation of eNOS function,amelioration of PKCβ-mediated oxidative stress and subsequent cardiomyocyte apoptosis.Fucoidan is therefore a potential candidate drug for protection of endothelium and heart in diabetic cardiovascular complications.
文摘An improved CBB staining with higher sensitivity than that of the typical CBB staining was reported.The main improvement was using a fixing step of 25% trichloroacetic acid(TCA) before CBB staining.For most proteins studied,the sensitivity of the improved CBB staining was about twice as high as that of the typical method.For basic and low molecular weight proteins such as ribosomal proteins,the sensitivity of this improved staining method was about 3.5-28 times that of the typical method.It was speculated that the improved procedure would be suitable for exact quantitative analysis of proteins fractionated by SDS-PAGE,especially for basic and low molecular weight proteins.On the other hand,this new modified method might be also applied to multidisciplinary studies,such as biological researches and nuclear sciences.
