The aim of this study is to find the experimental evidence that the precursor frequency of alloreactive CTLs is proportional to the number of the T-cell epitope specificities. The number of T-cell epitope specificitie...The aim of this study is to find the experimental evidence that the precursor frequency of alloreactive CTLs is proportional to the number of the T-cell epitope specificities. The number of T-cell epitope specificities was manipulated by pulsing different humor of HLA-A2 restricted peptide（s） onto the T2 cells, which acted as stimulating cells to elicit allo-reaction by co-culturing with peripheral blood lymphocytes （PBLs） of HLA-A2 negative individual. Ten HLA-A2 restricted peptides （all were normal cell components ） were synthesized, and cell peptide extract was prepared by frozen and thawed. T2 cells loaded with different number of peptide（s） were co-cultured with PBLs of an HLA-A2 negative individual; the latter were stained with PKH67 in advance. Then the proliferation was monitored with flow cytometry, and the precursor frequency of the effector cells was ＇analyzed by the ModFit Software. After 6 d of culture, no proliferation was observed in the bulk culture of PBL alone, and obvious proliferation took place when PBLs of the HLA-A2 negative were co-cultured with T2 cells loaded with or without loading peptide（ s）. The precursor frequency of the alloreactive CTLs was 0.052 819 for co-culture with T2 cells loaded without peptide; however it was 0. 030 429 for T2 cells with EBV/LMP2A and 0. 030 528 for T2 cells loaded with a single autogeneic peptide, and increased up to 0. 144 942 for T2 cells loaded with 10 autogeneic peptides; the precursor frequency was 0. 203 649 when co-cultured with T2 cells loaded with miscellaneous peptides extracted from the cytoplasm of T2 cells. This study reveals that the precursor frequency of alloreactive CTLs is proportional to the number of T-cell epitope specificities, and independent of the density of the allogeneic HLA Class Ⅰ molecule. Our findings support the hypothesis that the alloreactive T cell populations comprise miscellaneous T cell clones; each is specific to corresponding pMHC. The novel constellation of peptides presented by allogeneic MHC molecules makes thousands of different epitopes, which account for the exceptional high precursor frequency of alloreactive T cells.展开更多
Background We showed in our previous study that the N-terminal 17-mer peptide of amyloid precursor protein （APP17-mer peptide）,an active peptide segment with trophic and antioxidative effects,protects skin fibroblas...Background We showed in our previous study that the N-terminal 17-mer peptide of amyloid precursor protein （APP17-mer peptide）,an active peptide segment with trophic and antioxidative effects,protects skin fibroblasts against ultraviolet （UV） damage and downregulates matrix metalloproteinase 1 （MMP-1） expression.The aim of the current study was to explore the protective effects of P165,the N-terminal 5-mer peptide analog of amyloid precursor protein that is resistant to enzymolysis,on UVA-induced damage in human dermal fibroblasts （HDFs）.Methods HDFs were cultured in Dulbecco＆#39;s modified Eagle＆#39;s medium without and with P165 （concentrations were 1,10,and 100 μJmol/L）.Then,15 J/cm2 UVA irradiation was used to obtain the UV-irradiated model.Cell proliferation was analyzed using MTT kit.The collagen type Ⅰ and MMP-1 contents in cell lysate were determined by enzyme-linked immunosorbent assay （ELISA）.Fluorometric assays were performed to detect the formation of intracellular reactive oxygen species （ROS） in the cells.Results P165 significantly protected the HDFs against UVA-induced cytotoxicity.Compared with the UVA-irradiated control,1,10,and 100 μmol/L P165 elevated cell proliferation by 14.98% （P〈0.05）,17.52% （P〈0.01） and 28.34% （P〈0.001）,respectively.Simultaneously,10 and 100 μmol/L P165 increased collagen type Ⅰ content （both P〈0.05）.Moreover,P165 treatment （all concentrations） also markedly suppressed the UVA-induced MMP-1 expression （all P〈0.001）.P165 at 1,10,and 100 μmol/L also reduced UVA-induced ROS generation by 11.27%,13.69% （both P〈0.05）,and 25.48% （P〈0.001）,respectively.Conclusions P165 could protect the HDFs against UVA-induced photodamage,including cytotoxicity,and MMP-1 generation.Furthermore,it also increased the collagen type Ⅰ content in the cells.The inhibitory effect on intracellular ROS generation might be involved in these photoprotective effects.Thus,P165 may be a useful candidate in the prevention and treatment of skin photoaging.展开更多
Natriuretic peptide precursor A(NPPA)is synthesized,stored,and released by atrial myocytes.Previous studies have shown that NPPA plays a significant role in the regulation of coronary circulation and in atherosclerosis...Natriuretic peptide precursor A(NPPA)is synthesized,stored,and released by atrial myocytes.Previous studies have shown that NPPA plays a significant role in the regulation of coronary circulation and in atherosclerosis.Rs5065 NPPA gene polymorphism leads to the translation of NPPA with two additional arginines and has been suggested to be associated with salt-sensitive hypertension.The purpose of the present study was to investigate the relationship between the rs5065 NPPA gene polymorphism and the risk of coronary heart disease(CHD)in Chinese Han population.We genotyped the single nucleotide polymorphism(SNP)rs5065 NPPA in the human NPPA gene in 1861 sex-and age-matched subjects,comprising of 904 CHD cases and 957 controls of Chinese Han population.Genotyping of SNP was performed with Taqman SNP allelic discrimination assays by means of an ABI 7900HT.Our study showed that the frequencies of rs5065 NPPA C allele in the case and the control groups were 0.012 and 0.005,respectively.There was significant difference in C allele frequency distribution between the two groups(OR=2.607,95%CI:1.197–5.678,P=0.012).In the case group,there was significant difference between smokers and nonsmokers with subjects carrying C allele(P=0.037),and no significant difference in gender,age,fasting total cholesterol(TC),triglycerides(TG),fasting plasma glucose(FPG),body mass index(BMI),and blood pressure(BP)between the cases and the controls(P>0.05).Our results suggest that the C allele of rs5065 NPPA gene polymorphism may be associated with the risk of CHD.展开更多
基金The work was supported by the grants from the National Natural Science Foundation of China(No.30271201)the Major State Basic Research Development Program of China(No.2001C510008).
文摘The aim of this study is to find the experimental evidence that the precursor frequency of alloreactive CTLs is proportional to the number of the T-cell epitope specificities. The number of T-cell epitope specificities was manipulated by pulsing different humor of HLA-A2 restricted peptide（s） onto the T2 cells, which acted as stimulating cells to elicit allo-reaction by co-culturing with peripheral blood lymphocytes （PBLs） of HLA-A2 negative individual. Ten HLA-A2 restricted peptides （all were normal cell components ） were synthesized, and cell peptide extract was prepared by frozen and thawed. T2 cells loaded with different number of peptide（s） were co-cultured with PBLs of an HLA-A2 negative individual; the latter were stained with PKH67 in advance. Then the proliferation was monitored with flow cytometry, and the precursor frequency of the effector cells was ＇analyzed by the ModFit Software. After 6 d of culture, no proliferation was observed in the bulk culture of PBL alone, and obvious proliferation took place when PBLs of the HLA-A2 negative were co-cultured with T2 cells loaded with or without loading peptide（ s）. The precursor frequency of the alloreactive CTLs was 0.052 819 for co-culture with T2 cells loaded without peptide; however it was 0. 030 429 for T2 cells with EBV/LMP2A and 0. 030 528 for T2 cells loaded with a single autogeneic peptide, and increased up to 0. 144 942 for T2 cells loaded with 10 autogeneic peptides; the precursor frequency was 0. 203 649 when co-cultured with T2 cells loaded with miscellaneous peptides extracted from the cytoplasm of T2 cells. This study reveals that the precursor frequency of alloreactive CTLs is proportional to the number of T-cell epitope specificities, and independent of the density of the allogeneic HLA Class Ⅰ molecule. Our findings support the hypothesis that the alloreactive T cell populations comprise miscellaneous T cell clones; each is specific to corresponding pMHC. The novel constellation of peptides presented by allogeneic MHC molecules makes thousands of different epitopes, which account for the exceptional high precursor frequency of alloreactive T cells.
基金This work was supported in part by a grant from the National Natural Science Foundation of China
文摘Background We showed in our previous study that the N-terminal 17-mer peptide of amyloid precursor protein （APP17-mer peptide）,an active peptide segment with trophic and antioxidative effects,protects skin fibroblasts against ultraviolet （UV） damage and downregulates matrix metalloproteinase 1 （MMP-1） expression.The aim of the current study was to explore the protective effects of P165,the N-terminal 5-mer peptide analog of amyloid precursor protein that is resistant to enzymolysis,on UVA-induced damage in human dermal fibroblasts （HDFs）.Methods HDFs were cultured in Dulbecco＆#39;s modified Eagle＆#39;s medium without and with P165 （concentrations were 1,10,and 100 μJmol/L）.Then,15 J/cm2 UVA irradiation was used to obtain the UV-irradiated model.Cell proliferation was analyzed using MTT kit.The collagen type Ⅰ and MMP-1 contents in cell lysate were determined by enzyme-linked immunosorbent assay （ELISA）.Fluorometric assays were performed to detect the formation of intracellular reactive oxygen species （ROS） in the cells.Results P165 significantly protected the HDFs against UVA-induced cytotoxicity.Compared with the UVA-irradiated control,1,10,and 100 μmol/L P165 elevated cell proliferation by 14.98% （P〈0.05）,17.52% （P〈0.01） and 28.34% （P〈0.001）,respectively.Simultaneously,10 and 100 μmol/L P165 increased collagen type Ⅰ content （both P〈0.05）.Moreover,P165 treatment （all concentrations） also markedly suppressed the UVA-induced MMP-1 expression （all P〈0.001）.P165 at 1,10,and 100 μmol/L also reduced UVA-induced ROS generation by 11.27%,13.69% （both P〈0.05）,and 25.48% （P〈0.001）,respectively.Conclusions P165 could protect the HDFs against UVA-induced photodamage,including cytotoxicity,and MMP-1 generation.Furthermore,it also increased the collagen type Ⅰ content in the cells.The inhibitory effect on intracellular ROS generation might be involved in these photoprotective effects.Thus,P165 may be a useful candidate in the prevention and treatment of skin photoaging.
文摘Natriuretic peptide precursor A(NPPA)is synthesized,stored,and released by atrial myocytes.Previous studies have shown that NPPA plays a significant role in the regulation of coronary circulation and in atherosclerosis.Rs5065 NPPA gene polymorphism leads to the translation of NPPA with two additional arginines and has been suggested to be associated with salt-sensitive hypertension.The purpose of the present study was to investigate the relationship between the rs5065 NPPA gene polymorphism and the risk of coronary heart disease(CHD)in Chinese Han population.We genotyped the single nucleotide polymorphism(SNP)rs5065 NPPA in the human NPPA gene in 1861 sex-and age-matched subjects,comprising of 904 CHD cases and 957 controls of Chinese Han population.Genotyping of SNP was performed with Taqman SNP allelic discrimination assays by means of an ABI 7900HT.Our study showed that the frequencies of rs5065 NPPA C allele in the case and the control groups were 0.012 and 0.005,respectively.There was significant difference in C allele frequency distribution between the two groups(OR=2.607,95%CI:1.197–5.678,P=0.012).In the case group,there was significant difference between smokers and nonsmokers with subjects carrying C allele(P=0.037),and no significant difference in gender,age,fasting total cholesterol(TC),triglycerides(TG),fasting plasma glucose(FPG),body mass index(BMI),and blood pressure(BP)between the cases and the controls(P>0.05).Our results suggest that the C allele of rs5065 NPPA gene polymorphism may be associated with the risk of CHD.
