[Objective] The research aimed to discuss the effects of rosiglitazone and serum on the expressions of PPARα and PPARγ genes in the induced differentiation process of pig preadipocyte.[Method] The pig preadipocyte w...[Objective] The research aimed to discuss the effects of rosiglitazone and serum on the expressions of PPARα and PPARγ genes in the induced differentiation process of pig preadipocyte.[Method] The pig preadipocyte was separated by using the collagenase digestion method.Three kinds of different differentiation culture solutions were used to induce the differentiation of pig preadipocyte.The oil red O staining extraction method was used to contrast the influences of different differentiation culture solutions on the variation of cellular fat content in the differentiation process.Moreover,the variation trends of PPARα and PPARγ expressions in the cellular differentiation process in the different differentiation culture solutions were detected by the real-time quantification PCR.[Result] The cellular fat accumulation was the fastest in MII which contained rosiglitazone and was the slowest in MI which didn＇t contain rosiglitazone.Rosiglitazone could significantly increase the expression of PPARγ gene（P0.01）,but had the certain inhibition effect on the expression of PPARα gene,which wasn＇t significant.The serum had the extremely significant up-regulation effect on the expression of PPARγ gene（P0.01）,but had the extremely significant down-regulation effect on the expression of PPARα gene（P0.01）.[Conclusion] Rosiglitazone could greatly promote the expression of PPARγ gene,which increased the cellular fat deposition.Maybe the activator of PPARγ gene existed in the serum,and the inhibitor of PPARα gene existed simultaneously.展开更多
The present study investigates the molecular details of how arsenic trioxide inhibits preadipocyte differentiation and examines the role of Akt/PKB in regulation of differentiation and apoptosis. Continual exposure of...The present study investigates the molecular details of how arsenic trioxide inhibits preadipocyte differentiation and examines the role of Akt/PKB in regulation of differentiation and apoptosis. Continual exposure of arsenic trioxide, at the clinic achievable dosage that does not induce apoptosis, suppressed 3T3-L1 cell differentiation into fat cells by inhibiting the expression of PPARγ and C/EBPα and disrupting the interaction between PPARγ and RXRα, which determines the programming of the adipogenic genes. Interestingly, if we treated the cells for 12 or 24 h and then withdrew arsenic trioxide, the cells were able to differentiate to the comparable levels of untreated cells as assayed by the activity of GAPDH, the biochemical marker of preadipocyte differentiation. Long term treatment blocked the differentiation and the activity of GAPDH could not recover to the comparable levels of untreated cells. Continual exposure of arsenic trioxide caused accumulation in G2/M phase and the accumulation of p21. We found that arsenic trioxide induced the expression and the phosphorylation of Akt/PKB and it inhibited the interaction between Akt/PKB and PPARγ . Akt/PKB inhibitor appears to block the arsenic trioxide suppression of differentiation. Our results suggested that Akt/PKB may play a role in suppression of apoptosis and negatively regulate preadipocyte differentiation.展开更多
SIRT1 plays an important role in adipogenesis, but how SIRT1 is regulated in adipogenesis is largely unknown. In this study, we show that both SIRT1 protein and mRNA levels were increased along with CCAAT/enhancer-bin...SIRT1 plays an important role in adipogenesis, but how SIRT1 is regulated in adipogenesis is largely unknown. In this study, we show that both SIRT1 protein and mRNA levels were increased along with CCAAT/enhancer-binding protein a （C/EBPa） during adipocyte differentiation. C/EBPa, but not C/EBPap30, activated SIRT1 promoter in both HeLa cells and 3T3-L1 preadipocytes. Furthermore, C/EBPa upregulated SIRT1 mRNA and protein levels in HeLa cells and increased SIRT1 expression in a p53-independent manner in Soas2 cells. In preadipocytes, ectopic expression of C/EBPa upregulated SIRT1 protein level and knockdown of C/EBPa led to the decrease of SIRTI pro- tein level. Moreover, by promoter deletion analysis, gel shift assay and chromatin immunoprecipitation, we found that C/EBPa bound to the SIRT1 promoter at a consensus C/EBPα binding site. These data demonstrate that C/ EBPα regulates SIRT1 expression during adipogenesis by directly binding to the SIRT1 promoter.展开更多
The thermal debinding behavior of stainless steel foam precursor in vacuum was studied and compared with that in hydrogen.The formation cause of pore channel was analyzed.The experiment results show that the binder re...The thermal debinding behavior of stainless steel foam precursor in vacuum was studied and compared with that in hydrogen.The formation cause of pore channel was analyzed.The experiment results show that the binder removal rate in vacuum is higher than that in hydrogen.In vacuum,the organic compounds can be removed effectively without change of pore size and the pore morphology for the sample.After pre-sintering,some sintering necks form and the sample has certain intensity.The initial surface pore forms with the temperature increasing at first,and then the internal melting binder is aspirated to form initial pore because of the capillary force and the metal powders re-arrange with the migration of binder at the same time.展开更多
Objective To study the effects of emodin on proliferation and differentiation of 3T3 L1 preadipocyte and the possible mechanism Methods Cell proliferation was determined by MTT spectrophotometry, cell differentiat...Objective To study the effects of emodin on proliferation and differentiation of 3T3 L1 preadipocyte and the possible mechanism Methods Cell proliferation was determined by MTT spectrophotometry, cell differentiation was determined by Oil Red O staining, and fatty acid synthase (FAS) activity was determined by spectrophotometry Results Emodin promoted proliferation of 3T3 L1 preadipocyte at low concentration and inhibited the proliferation at high concentration in a dose related manner In contrast, it inhibited cell differentiation into adipocyte at low concentration in a dose related manner In vitro emodin inhibited the activity of FAS in a dose related manner Conclusions The effects of emodin on 3T3 L1 cell's proliferation and differentiation are dose dependent Emodin inhibits the activity of FAS Our results suggest that emodin should have a potential to serve as a fat reducing drug展开更多
To investigate the differentiation mechanism of grass carp preadipocytes, a primary adipocytes culture system was established. Confluent preadipocytes were induced to differentiation, and the morphology and gene expre...To investigate the differentiation mechanism of grass carp preadipocytes, a primary adipocytes culture system was established. Confluent preadipocytes were induced to differentiation, and the morphology and gene expression were evaluated at different stages. It was shown that preadipocytes were gradually filled with droplets and the cellular lipid content increased during the differentiation. Ultrastructure observation indicated that the number of mitochondria increased with adipocytes differentiation. Consistently, the mitochondrial protein content was ele- vated in the differentiating adipocytes, qRT-PCR showed that the expression level of lipogenesis-related genes such as peroxisome proliferator activator receptor 7 （PPAR 7）, lipoprotein lipase （LPL）, fatty acid synthase （FAS） and stearoyl-CoA desaturase （SCD） increased during adipocytes differentiation. The mitochondrial relevant gene also elevated when adipocyte differentiation, such as PPAR coactivator-1 （PGC-1 α）, PGC-1β and nuclear respiratory factor （NRF-1）. However, the expression of carnitine palmitoyltransferase 1α （CPT-1 α） gene decreased at the initial stage, but increased at the last stage of cell differ- entiation. These results indicated that the differentiation process of grass carp preadipocytes is similar to that of land animals, but the molecular mechanisms are not exactly the same. The findings revealed in this study provides new information to the study of fish adipocyte differentiation.展开更多
Obesity is primarily caused by the excessive accumulation of white adipose tissues(WAT). We previously obtained an adipocyte-specific aptamer termed Adipo8 in vitro. In this present study, this adipocyte-specific apta...Obesity is primarily caused by the excessive accumulation of white adipose tissues(WAT). We previously obtained an adipocyte-specific aptamer termed Adipo8 in vitro. In this present study, this adipocyte-specific aptamer Adipo8 was first chemically modified by introduction of phosphorothioate linkages(PS-linkages) and then conjugated to polyethylene glycol(PEG), we tested whether this modified aptamer could distinguish mature white adipocytes from 3T3-L1 preadipocytes or brown adipocytes. To verify the binding affinity of this aptamer to mature white adipocytes in vivo as well as in vitro, we tested whether modified Adipo8 could specifically bind to the WAT of Diet-Induced Obesity(DIO) C57BL/6 mice. Finally, we examined the effect of Adipo8 on the adipogenic differentiation of mature white adipocytes. Based on our results, PS-modified aptamer demonstrated its high binding affinity and specificity, and was able to distinguish white adipocytes from 3T3-L1 preadipocytes or brown adipocytes in vitro. PS-modified Adipo8 also demonstrated more biostability and prolonged binding time in biological fluids. Additionally, Adipo8 could inhibit adipogenic differentiation of adipose tissue, possibly by inhibiting the expression of PPAR-γ in adipose tissue. This modified aptamer holds great promise as a stable molecular recognition tool for targeted delivery to adipocytes and has potential in the treatment of obesity.展开更多
基金Supported by Ministry of Science & Technology International Cooper-ation Project(2011DFB30340)the Earmarked Fund for China Agriculture Research System(CARS-36)the Project of Animal Breeding from Sichuan Bureau of Science & Technology(2006-YZGG-15)~~
文摘[Objective] The research aimed to discuss the effects of rosiglitazone and serum on the expressions of PPARα and PPARγ genes in the induced differentiation process of pig preadipocyte.[Method] The pig preadipocyte was separated by using the collagenase digestion method.Three kinds of different differentiation culture solutions were used to induce the differentiation of pig preadipocyte.The oil red O staining extraction method was used to contrast the influences of different differentiation culture solutions on the variation of cellular fat content in the differentiation process.Moreover,the variation trends of PPARα and PPARγ expressions in the cellular differentiation process in the different differentiation culture solutions were detected by the real-time quantification PCR.[Result] The cellular fat accumulation was the fastest in MII which contained rosiglitazone and was the slowest in MI which didn＇t contain rosiglitazone.Rosiglitazone could significantly increase the expression of PPARγ gene（P0.01）,but had the certain inhibition effect on the expression of PPARα gene,which wasn＇t significant.The serum had the extremely significant up-regulation effect on the expression of PPARγ gene（P0.01）,but had the extremely significant down-regulation effect on the expression of PPARα gene（P0.01）.[Conclusion] Rosiglitazone could greatly promote the expression of PPARγ gene,which increased the cellular fat deposition.Maybe the activator of PPARγ gene existed in the serum,and the inhibitor of PPARα gene existed simultaneously.
基金This work is supported by grants from National Nature Science Foundation of China(No.30000083)Quan.CHEN's laboratory was supported by grants“Knowledge Innovation Key Project"(kscx2-sw-2010)of Chinese Academy of Sciences+1 种基金the National Basic Research Program of China(973 program project,No.2002CB5 13 100)National Fund for Outstanding Young Scholars from NSFC(30325013)awarded to Quan CHEN.
文摘The present study investigates the molecular details of how arsenic trioxide inhibits preadipocyte differentiation and examines the role of Akt/PKB in regulation of differentiation and apoptosis. Continual exposure of arsenic trioxide, at the clinic achievable dosage that does not induce apoptosis, suppressed 3T3-L1 cell differentiation into fat cells by inhibiting the expression of PPARγ and C/EBPα and disrupting the interaction between PPARγ and RXRα, which determines the programming of the adipogenic genes. Interestingly, if we treated the cells for 12 or 24 h and then withdrew arsenic trioxide, the cells were able to differentiate to the comparable levels of untreated cells as assayed by the activity of GAPDH, the biochemical marker of preadipocyte differentiation. Long term treatment blocked the differentiation and the activity of GAPDH could not recover to the comparable levels of untreated cells. Continual exposure of arsenic trioxide caused accumulation in G2/M phase and the accumulation of p21. We found that arsenic trioxide induced the expression and the phosphorylation of Akt/PKB and it inhibited the interaction between Akt/PKB and PPARγ . Akt/PKB inhibitor appears to block the arsenic trioxide suppression of differentiation. Our results suggested that Akt/PKB may play a role in suppression of apoptosis and negatively regulate preadipocyte differentiation.
文摘SIRT1 plays an important role in adipogenesis, but how SIRT1 is regulated in adipogenesis is largely unknown. In this study, we show that both SIRT1 protein and mRNA levels were increased along with CCAAT/enhancer-binding protein a （C/EBPa） during adipocyte differentiation. C/EBPa, but not C/EBPap30, activated SIRT1 promoter in both HeLa cells and 3T3-L1 preadipocytes. Furthermore, C/EBPa upregulated SIRT1 mRNA and protein levels in HeLa cells and increased SIRT1 expression in a p53-independent manner in Soas2 cells. In preadipocytes, ectopic expression of C/EBPa upregulated SIRT1 protein level and knockdown of C/EBPa led to the decrease of SIRTI pro- tein level. Moreover, by promoter deletion analysis, gel shift assay and chromatin immunoprecipitation, we found that C/EBPa bound to the SIRT1 promoter at a consensus C/EBPα binding site. These data demonstrate that C/ EBPα regulates SIRT1 expression during adipogenesis by directly binding to the SIRT1 promoter.
基金Project(50974136)supported by the National Natural Science Foundation of ChinaProject(CX2009B037)supported by the Graduate Degree Thesis Innovation Foundation of Central South University,China
文摘The thermal debinding behavior of stainless steel foam precursor in vacuum was studied and compared with that in hydrogen.The formation cause of pore channel was analyzed.The experiment results show that the binder removal rate in vacuum is higher than that in hydrogen.In vacuum,the organic compounds can be removed effectively without change of pore size and the pore morphology for the sample.After pre-sintering,some sintering necks form and the sample has certain intensity.The initial surface pore forms with the temperature increasing at first,and then the internal melting binder is aspirated to form initial pore because of the capillary force and the metal powders re-arrange with the migration of binder at the same time.
文摘Objective To study the effects of emodin on proliferation and differentiation of 3T3 L1 preadipocyte and the possible mechanism Methods Cell proliferation was determined by MTT spectrophotometry, cell differentiation was determined by Oil Red O staining, and fatty acid synthase (FAS) activity was determined by spectrophotometry Results Emodin promoted proliferation of 3T3 L1 preadipocyte at low concentration and inhibited the proliferation at high concentration in a dose related manner In contrast, it inhibited cell differentiation into adipocyte at low concentration in a dose related manner In vitro emodin inhibited the activity of FAS in a dose related manner Conclusions The effects of emodin on 3T3 L1 cell's proliferation and differentiation are dose dependent Emodin inhibits the activity of FAS Our results suggest that emodin should have a potential to serve as a fat reducing drug
基金supported by the National Natural Science Foundation of China(31072223)the National Basic Research Program of China(2014CB138603)
文摘To investigate the differentiation mechanism of grass carp preadipocytes, a primary adipocytes culture system was established. Confluent preadipocytes were induced to differentiation, and the morphology and gene expression were evaluated at different stages. It was shown that preadipocytes were gradually filled with droplets and the cellular lipid content increased during the differentiation. Ultrastructure observation indicated that the number of mitochondria increased with adipocytes differentiation. Consistently, the mitochondrial protein content was ele- vated in the differentiating adipocytes, qRT-PCR showed that the expression level of lipogenesis-related genes such as peroxisome proliferator activator receptor 7 （PPAR 7）, lipoprotein lipase （LPL）, fatty acid synthase （FAS） and stearoyl-CoA desaturase （SCD） increased during adipocytes differentiation. The mitochondrial relevant gene also elevated when adipocyte differentiation, such as PPAR coactivator-1 （PGC-1 α）, PGC-1β and nuclear respiratory factor （NRF-1）. However, the expression of carnitine palmitoyltransferase 1α （CPT-1 α） gene decreased at the initial stage, but increased at the last stage of cell differ- entiation. These results indicated that the differentiation process of grass carp preadipocytes is similar to that of land animals, but the molecular mechanisms are not exactly the same. The findings revealed in this study provides new information to the study of fish adipocyte differentiation.
基金supported by the National Natural Science Foundation of China(81370983,81400864)the National Key Scientific Instrument and Equipment Development Projects(2011YQ0301241403)+2 种基金the Hunan Province Natural Science Key Fund Project(2014SK2003)the Foundation of China Hunan Provincial Science & Technology Department(2012FJ4371,S2014S2032,2014FJ3109)the Fundamental Research Funds for the Central Universities of Central South University(2013 zzts083)
文摘Obesity is primarily caused by the excessive accumulation of white adipose tissues(WAT). We previously obtained an adipocyte-specific aptamer termed Adipo8 in vitro. In this present study, this adipocyte-specific aptamer Adipo8 was first chemically modified by introduction of phosphorothioate linkages(PS-linkages) and then conjugated to polyethylene glycol(PEG), we tested whether this modified aptamer could distinguish mature white adipocytes from 3T3-L1 preadipocytes or brown adipocytes. To verify the binding affinity of this aptamer to mature white adipocytes in vivo as well as in vitro, we tested whether modified Adipo8 could specifically bind to the WAT of Diet-Induced Obesity(DIO) C57BL/6 mice. Finally, we examined the effect of Adipo8 on the adipogenic differentiation of mature white adipocytes. Based on our results, PS-modified aptamer demonstrated its high binding affinity and specificity, and was able to distinguish white adipocytes from 3T3-L1 preadipocytes or brown adipocytes in vitro. PS-modified Adipo8 also demonstrated more biostability and prolonged binding time in biological fluids. Additionally, Adipo8 could inhibit adipogenic differentiation of adipose tissue, possibly by inhibiting the expression of PPAR-γ in adipose tissue. This modified aptamer holds great promise as a stable molecular recognition tool for targeted delivery to adipocytes and has potential in the treatment of obesity.
