Objective： To investigate the effects of rosiglitazone, a synthetic ligand of peroxisome proliferators-activated receptor gamma （PPARγ）, on the expression of acyl-coenzyme A： cholesterol acyltransferase-1 （ACAT-...Objective： To investigate the effects of rosiglitazone, a synthetic ligand of peroxisome proliferators-activated receptor gamma （PPARγ）, on the expression of acyl-coenzyme A： cholesterol acyltransferase-1 （ACAT-1） in phorbol myristate acetate （PMA）-pretreated THP-1 cells after the inducement of advanced glycation end products （AGEs）. Methods： After THP-1 cells were cultured in the presence of 0.1 μmol/L PMA for 72 h to induce phagocytic differentiation, the obtained THP-1 macrophages were treated with rosiglitazone for 4 h at different concentrations （1, 5 or 10 μmol/L） and then exposed to AGEs-modified bovine serum albumin （AGEs-BSA） for 24 h at a concentration of 200 mg/L. Reverse transcription polymerase chain reaction （RT-PCR） and Western blot analysis were performed to detect the mRNA and protein expressions of ACAT-1 respectively. Results： Administration of AGEs-BSA （200 mg/L） into the THP-1 macrophages resulted in up-regulation of ACAT-1 at mRNA and protein levels when compared with the expressions in macrophages incubated with serum-free RPMI1640. Pretreatment of rosiglitazone inhibited significantly the increased expression of ACAT-1 induced by AGEs-BSA in a concentration-dependent manner. Conclusion： PPARy activation by rosiglitazone down-regulates ACAT-1 expression induced by AGEs in THP-1 macrophages, which might provide a new way for treating atherogenesis in diabetic patients.展开更多
AIM： To explore the relationship between DNA methyltransferase 1 （DNMT1） and hepatitis B virus （HBV）-related hepatocellular carcinoma （HCC） and its biological significance in primary HCC. METHODS： We carried o...AIM： To explore the relationship between DNA methyltransferase 1 （DNMT1） and hepatitis B virus （HBV）-related hepatocellular carcinoma （HCC） and its biological significance in primary HCC. METHODS： We carried out an immunohistochemical examination of DNMT1 in both HCC and paired nonneoplastic liver tissues from Chinese subjects. DNMT1 mRNA was further examined in HCC cell lines by real-time PCR. We inhibited DNMT1 using siRNA and detected the effect of depletion of DNMT1 on cell proliferation ability and cell apoptosis in the HCC celt line SMMC-7721. RESULTS： DNMT1 protein expression was increased in HCCs compared to histologically normal nonneoplastic liver tissues and the incidence of DNMT1 immunoreactivity in HCCs correlated significantly with poor tumor differentiation （P = 0.014）. There were more cases with DNMT1 overexpression in HCC with HBV （42.85%） than in HCC without HBV （28.57%）. However, no significant difference in DNMT1 expression was found in HBV-positive and HBV-negative cases in the Chinese HCC group. There was a trend that DNMT1 RNA expression increased more in HCC cell lines than in pericarcinoma cell lines and normal liver cell lines. In addition, we inhibited DNMT1 using siRNA in the SMMC-7721 HCC cell line and found depletion of DNMT1 suppressed cells growth independent of expression of proliferating cell nuclear antigen （PCNA）, even in HCC cell lines where DNMT1 was stably decreased. CONCLUSION： The findings implied that DNMT1 plays a key role in HBV-retated hepatocellular tumorigenesis. Depletion of DNMT1 mediates growth suppression in SMMC-7721 cells.展开更多
DNA methylation is a critical epigenetic mechanism that influences gene transcription, genomic stability, X-chromosome inactivation and other factors, and appropriate DNA methylation is crucial in development. DNA met...DNA methylation is a critical epigenetic mechanism that influences gene transcription, genomic stability, X-chromosome inactivation and other factors, and appropriate DNA methylation is crucial in development. DNA methyltransferase 1 （DNMT1） plays an important role in maintaining the established methylation pattern during DNA replication. Although the effect of DNA methylation on embryonic development has been well known in vertebrates, little research has been carried out in invertebrates, especially in marine bivalves. In this study, the DNMT1 gene （MyDNMT1） was firstly identified from Mizuhopecten yessoensis. The full-length cDNA of MyDNMT1 was 5 039 bp, consisted of a 5＇ untranslated region （5＇-UTR） of 79 bp, a 3＇ untranslated region （3＇-UTR） of 199 bp, and a 4 761 bp open reading frame （ORF） encoding a peptide of 1 586 amino acids without a putative signal peptide. The relative mRNA expression level of MyDNMT1 was measured during the embryonic development of M. ydssoensis using real-time PCR, which revealed that the level at stage zygote and trochophore were significantly higher than that at other stages. We further examined the global DNA methylation during development by colorimetric method. The results showed that the methylation level was increased and reached the peak at blastula stage, then dramatically decreased, and fluctuated at early D-shaped larva stage. This study provided greater insight into the DNA methylation of embryonic development, which obtained a better understanding of the relationship between the DNA methylation and the embryonic development in bivalve mollusks.展开更多
文摘Objective： To investigate the effects of rosiglitazone, a synthetic ligand of peroxisome proliferators-activated receptor gamma （PPARγ）, on the expression of acyl-coenzyme A： cholesterol acyltransferase-1 （ACAT-1） in phorbol myristate acetate （PMA）-pretreated THP-1 cells after the inducement of advanced glycation end products （AGEs）. Methods： After THP-1 cells were cultured in the presence of 0.1 μmol/L PMA for 72 h to induce phagocytic differentiation, the obtained THP-1 macrophages were treated with rosiglitazone for 4 h at different concentrations （1, 5 or 10 μmol/L） and then exposed to AGEs-modified bovine serum albumin （AGEs-BSA） for 24 h at a concentration of 200 mg/L. Reverse transcription polymerase chain reaction （RT-PCR） and Western blot analysis were performed to detect the mRNA and protein expressions of ACAT-1 respectively. Results： Administration of AGEs-BSA （200 mg/L） into the THP-1 macrophages resulted in up-regulation of ACAT-1 at mRNA and protein levels when compared with the expressions in macrophages incubated with serum-free RPMI1640. Pretreatment of rosiglitazone inhibited significantly the increased expression of ACAT-1 induced by AGEs-BSA in a concentration-dependent manner. Conclusion： PPARy activation by rosiglitazone down-regulates ACAT-1 expression induced by AGEs in THP-1 macrophages, which might provide a new way for treating atherogenesis in diabetic patients.
基金Supported by National Natural Science Foundation of China,No.30470950
文摘AIM： To explore the relationship between DNA methyltransferase 1 （DNMT1） and hepatitis B virus （HBV）-related hepatocellular carcinoma （HCC） and its biological significance in primary HCC. METHODS： We carried out an immunohistochemical examination of DNMT1 in both HCC and paired nonneoplastic liver tissues from Chinese subjects. DNMT1 mRNA was further examined in HCC cell lines by real-time PCR. We inhibited DNMT1 using siRNA and detected the effect of depletion of DNMT1 on cell proliferation ability and cell apoptosis in the HCC celt line SMMC-7721. RESULTS： DNMT1 protein expression was increased in HCCs compared to histologically normal nonneoplastic liver tissues and the incidence of DNMT1 immunoreactivity in HCCs correlated significantly with poor tumor differentiation （P = 0.014）. There were more cases with DNMT1 overexpression in HCC with HBV （42.85%） than in HCC without HBV （28.57%）. However, no significant difference in DNMT1 expression was found in HBV-positive and HBV-negative cases in the Chinese HCC group. There was a trend that DNMT1 RNA expression increased more in HCC cell lines than in pericarcinoma cell lines and normal liver cell lines. In addition, we inhibited DNMT1 using siRNA in the SMMC-7721 HCC cell line and found depletion of DNMT1 suppressed cells growth independent of expression of proliferating cell nuclear antigen （PCNA）, even in HCC cell lines where DNMT1 was stably decreased. CONCLUSION： The findings implied that DNMT1 plays a key role in HBV-retated hepatocellular tumorigenesis. Depletion of DNMT1 mediates growth suppression in SMMC-7721 cells.
基金Supported by Earmarked Fund for Modern Agro-industry Technology Research System of China(CARS-49)Natural Science Foundation of Liaoning Province(201602408)~~
文摘DNA methylation is a critical epigenetic mechanism that influences gene transcription, genomic stability, X-chromosome inactivation and other factors, and appropriate DNA methylation is crucial in development. DNA methyltransferase 1 （DNMT1） plays an important role in maintaining the established methylation pattern during DNA replication. Although the effect of DNA methylation on embryonic development has been well known in vertebrates, little research has been carried out in invertebrates, especially in marine bivalves. In this study, the DNMT1 gene （MyDNMT1） was firstly identified from Mizuhopecten yessoensis. The full-length cDNA of MyDNMT1 was 5 039 bp, consisted of a 5＇ untranslated region （5＇-UTR） of 79 bp, a 3＇ untranslated region （3＇-UTR） of 199 bp, and a 4 761 bp open reading frame （ORF） encoding a peptide of 1 586 amino acids without a putative signal peptide. The relative mRNA expression level of MyDNMT1 was measured during the embryonic development of M. ydssoensis using real-time PCR, which revealed that the level at stage zygote and trochophore were significantly higher than that at other stages. We further examined the global DNA methylation during development by colorimetric method. The results showed that the methylation level was increased and reached the peak at blastula stage, then dramatically decreased, and fluctuated at early D-shaped larva stage. This study provided greater insight into the DNA methylation of embryonic development, which obtained a better understanding of the relationship between the DNA methylation and the embryonic development in bivalve mollusks.
