The aim of this study was to investigate the effect of activating transcription factor 3 (ATF3) on the differentiation of intramuscular preadipocytes in goat, and to elucidate its possible action pathway at the molecular level. In this study, the recombinant plasmid of goat pEGFP-N1-ATF3 was constructed, and the intramuscular preadipocytes were transfected with liposomes. The relative expression levels of adipocyte differentiation marker genes were detected by quantitative real-time PCR (qRT-PCR). After transfection of goat intramuscular preadipocytes with the goat pEGFP-N1-ATF3 overexpression vector, it was found that the accumulation of lipid droplets was inhibited, and the adipocyte differentiation markers PPARγ, C/EBPα and SREBP1 were extremely significantly down-regulated (P < 0.01), while C/EBPβ and AP2 were significantly down-regulated (P < 0.05). The ATF3 binding sites were predicted to exist in the promoter regions of PPARγ, C/EBPα and AP2 by the ALGGEN PROMO program. The overexpression of goat ATF3 inhibits the accumulation of lipid droplets in intramuscular preadipocytes, and this effect may be achieved by down-regulating PPARγ, C/EBPα and AP2. These results may facilitate elucidation of the regulatory mechanism of ATF3 in regulating the differentiation of goat intramuscular preadipocytes.
3T3-L1 Cells ; Activating Transcription Factor 3/pharmacology* ; Adipocytes ; Adipogenesis/genetics* ; Animals ; CCAAT-Enhancer-Binding Protein-alpha/pharmacology* ; Cell Differentiation ; Goats ; Mice ; PPAR gamma/metabolism*

OBJECTIVETo study the effect and mechanism of berberine (BER) on the proliferation and differentiation of adipocytes.

METHODSThe proliferation of 3T3-L1 pre-adipocytes was detected by XTT method. Lipid droplets accumulated in the cytoplasm of adipocytes in the differentiating process were observed by oil red O staining and quantified by colorimetry. The expressions of peroxisome proliferation activated receptor gamma (PPARgamma), CAAT/enhancer binding protein alpha (C/EBPalpha) mRNA and protein were detected by Real-time PCR and Western blotting respectively.

RESULTSIntervention with BER in concentration below 10 micromol/L for 24 h showed insignificant effect on the proliferation of adipocytes, as compared with that in the control group (P > 0.05); but that in concentrations 20, 40 and 80 micromol/L revealed significant suppressive effect; that in different concentrations acting for 48 h and 72 h could affect the proliferation and the effect displayed a dose-dependent manner, i. e. the higher the concentration of BER, the more apparent the suppression, showing significant difference as compared with those in the control group (P <0.05 or P <0.01). The pre-adipocyte treated with 10 micromol/L BER showed that the lipid droplets in the cytoplasm significantly lessened, so did the expression of differentiation related factor PPAR gamma mRNA as well as the expressions of C/EBPalpha mRNA and protein, as compared with those in the blank control group and the group intervened with rosiglitazone, the difference was significant (P < 0.05 or P < 0.01).

CONCLUSIONSBER can suppress the proliferation and differentiation of 3T3-L1 pre-adipocytes, reduce the accumulation of lipid drops in the adipocyte differentiating process, which may be associated with its effects in decreasing the expressions of adipocyte differentiation related gene PPARgamma, C/EBPalpha mRNA and protein. The study provides a basis for applying BER on the prevention and treatment of such metabolic related diseases as obesity.

3T3-L1 Cells ; Adipocytes ; cytology ; drug effects ; metabolism ; Animals ; Berberine ; pharmacology ; CCAAT-Enhancer-Binding Protein-alpha ; genetics ; metabolism ; Cell Proliferation ; drug effects ; Gene Expression ; drug effects ; Mice ; PPAR gamma ; genetics ; metabolism ; RNA, Messenger ; genetics ; metabolism

OBJECTIVETo study the effects and mechanisms of Huanglian Jiedu Decoction (HJD) and its disassembled recipes containing serums on the proliferation and differentiation of preadipocytes.

METHODSHJD and its disassembled recipes containing serums were prepared. The 3T3-L1 preadipocytes were cultured. The proliferation of 3T3-L1 preadipocytes was detected by methyl thiazolyl tetrazolium (MTT) method. The accumulation of lipid droplets in the cytoplasm of differentiated preadipocytes was observed by oil red O staining and quantitatively analyzed by colorimetry. The mRNA expressions of peroxisome proliferation activated receptor y (PPAR gamma) and CAAT/enhancer binding protein (C/EBP alpha) were detected by reverse transcription polymerase chain reaction (RT-PCR).

RESULTSIntervention with serum containing HJD, Phellodendron amurense Rupr plus Gardenia jasminoides Ellis, or Gardenia jasminoides Ellis showed significantly stimulative effects on the proliferation of preadipocytes, as compared with that in the blank control group (P<0.05, P<0.01). The preadipocytes treated with serum containing HJD, Phellodendron amurense Rupr plus Gardenia jasminoides Ellis, Coptis chinensis Franch or Gardenia jasminoides Ellis showed that the lipid droplets in the cytoplasm were significantly lessened, so did the mRNA expressions of PPAR gamma and C/EBP alpha when compared with the blank control group (P<0.05, P<0.01).

CONCLUSIONSHJD promoted the proliferation of preadipocytes, decreased the accumulation of lipid droplets during the differentiation of adipocytes, and inhibited the differentiation of adipocytes, which might be associated with its effects on decreasing the mRNA expressions of PPAR gamma and C/EBP alpha. Phellodendron amurense Rupr and Gardenia jasminoides Ellis were the main components of HJD playing these roles.

3T3-L1 Cells ; Adipocytes ; cytology ; drug effects ; metabolism ; Animals ; CCAAT-Enhancer-Binding Protein-alpha ; metabolism ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Mice ; PPAR gamma ; metabolism ; Rats ; Rats, Sprague-Dawley ; Serum

Obesity is associated with a number of metabolic abnormalities such as type 2 diabetes and has become a major health problem worldwide. In the present study, we investigated the effects of Epimedium koreanum Nakai (Herba Epimedii, HE) and its main constituent icariin on the adipocyte differentiation in 3T3-L1 preadipocytes. HE extract and icariin significantly reduced lipid accumulation and suppressed the expressions of PPARγ, C/EBPα, and SREBP-1c in 3T3-L1 adipocytes. They also inhibited fatty acid synthase (FAS), acyl-Co A synthase (ACS1), and perilipin. Moreover, HE extract and icariin markedly increased the phosphorylation of AMPK. These results indicated that HE extract and icariin can inhibit the adipocyte differentiation through downregulation of the adipogenic transcription factors, suggesting that HE containing icariin may be used as a potential therapeutic agent in the treatment and prevention of obesity.
3T3-L1 Cells ; Adipocytes ; cytology ; drug effects ; metabolism ; Adipogenesis ; drug effects ; Animals ; CCAAT-Enhancer-Binding Protein-alpha ; genetics ; metabolism ; Epimedium ; chemistry ; Flavonoids ; pharmacology ; Lipid Metabolism ; drug effects ; Mice ; PPAR gamma ; genetics ; metabolism ; Plant Extracts ; pharmacology ; Sterol Regulatory Element Binding Protein 1 ; genetics ; metabolism

OBJECTIVETo compare the effects of Astragalus polysaccharides (AP) and berberine (BB) on the adipocyte's carbohydrate metabolism and cell differentiation, for assessing the possible mechanism of them in improving carbohydrate metabolism.

METHODSAdipocytes were treated with AP or BE, the 3H-glucose up-take rate in them was investigated, those of differentiation phase were stained by oil red O to analyze the degree of cell differentiation by spectrophotography quantitatively. The adipocyte differentiation related expression of PPARgamma mRNA and C/EBPalpha mRNA were determined by RT-PCR.

RESULTSThe 3H-glucose up-take rate in the AP group and BE group were 109.3% and 182.7% of that in the blank control group respectively. AP obviously promoted the cell differentiation and up-regulated expression of PPARgamma mRNA, while BE suppressed the differentiation and expression of PPARgamma and C/EBPalpha mRNA distinctly, all showing significant difference as compared with that in the blank control (P<0.01).

CONCLUSIONAP could promote glucose up-take, cell differentiation and PPARgamma mRNA expression, BB also promote glucose up-take, but suppress the cell differentiation, and inhibit expressions of PPARgamma and C/EBPalpha mRNA in 3T3-L1 adipocytes.

3T3-L1 Cells ; Adipocytes ; cytology ; metabolism ; Animals ; Astragalus Plant ; chemistry ; Berberine ; pharmacology ; CCAAT-Enhancer-Binding Protein-alpha ; biosynthesis ; genetics ; Cell Differentiation ; drug effects ; Cell Division ; drug effects ; Drugs, Chinese Herbal ; chemistry ; pharmacology ; Glucose ; metabolism ; Mice ; PPAR gamma ; biosynthesis ; genetics ; Polysaccharides ; pharmacology ; RNA, Messenger ; genetics ; metabolism

OBJECTIVEThis study examined the effects of PI3K inhibitor LY294002 on the differentiation of mouse preadipocytes and the expression of CCAAT enhancer binding protein &alpha; (C/EBP&alpha;) and peroxisome proliferation activated receptor γ (PPARγ), in order to study the possible roles of insulin receptor substrate (IRSs)/PI3K signal pathway in the differentiation of preadipocytes.

METHODSThe mouse 3T3-L1 cells were cultured normally and divided into experimental and control groups. 3T3-L1 cells in the experimental group were treated with PI3K inhibitor LY294002 (25 μmol/L) and those in the control group were treated with DMSO culture medium. 3-isobutyl-1-methylxanthine (IBMX) (0.5 mmol/L), dexamethasone (10-6 mol/L) and insulin (5 μg/mL) were used to induce the differentiation of 3T3-L1 preadipocytes in both groups. Before culture, and 2, 4 and 8 days after culture, the cells were collected to detect the expression of C/EBP&alpha; and PPARγ by real-time PCR and Western blot assays. The lipid droplets of 3T3-L1 preadipocytes were observed by oil-red O staining.

RESULTSPI3K inhibitor LY294002 did not affect the expression of C/EBP&alpha; and PPARγ in un-induced 3T3-L1 preadipocytes (P>0.05), but decreased the expression of C/EBP&alpha; and PPARγ during the in vitro induced differentiation of 3T3-L1 preadipocytes compared with the control group (P<0.05 or 0.01). The lipid droplets count was greatly reduced by LY294002.

CONCLUSIONSPI3K inhibitor LY294002 can inhibit the differentiation of mouse 3T3-LI preadipocytes and the expression of C/EBP&alpha; and PPARγ in the differentiation of 3T3-LI preadipoeytes, suggesting that IRSs/PI3K signal pathway may play an important role in the differentiation of 3T3-L1 preadipocytes by regulating the expression of C/EBP&alpha; and PPARγ.

3T3-L1 Cells ; Adipocytes ; cytology ; drug effects ; Animals ; CCAAT-Enhancer-Binding Protein-alpha ; analysis ; genetics ; Cell Differentiation ; drug effects ; Chromones ; pharmacology ; Gene Expression Regulation ; drug effects ; Mice ; Morpholines ; pharmacology ; PPAR gamma ; analysis ; genetics ; Phosphatidylinositol 3-Kinases ; antagonists & inhibitors ; RNA, Messenger ; analysis

OBJECTIVETo figure out the function of C/EBPalpha in the monocytic differentiation of HL60 cells induced by a new steroidal drug NSC67657.

METHODSThe differentiation of HL60 cells was induced by NSC67657, and the cell surface antigen CD14 expression was detected by flow cytometry. The gene and protein expressions of CCAAT enhancer binding protein alpha (C/EBPalpha) before and after the induction of cell differentiation were determined by RT-PCR and Western blot. Eukaryotic expressing vector pDsRed-ICAT was constructed and transfected into HL60 cells, and its expression was verified. The effect of C/EBPalpha overexpression in HL60 cells was assessed by MTT assay, Wright's staining and flow cytometry before and after NSC67657 transfection.

RESULTSHL60 cells could be induced into monocytes by 10 micromol/L ATRA within 5 days, and the coverage of CD14 positive cells reached 93.9% after 5 days of drug treatment. The eukaryotic expressing vector was successfully constructed, and over 90% positive clones were obtained after screening by G418 and electrotransfection. The results of proliferative analysis, chemical staining, ultrastructural observation, and CD11b detection confirmed that HL60 cells could be induced into granulocytic differentiation by overexpression of C/EBPalpha protein. Moreover, in the drug treatment group, transfected cells could not be induced into monocytic differentiation, and their granulocytic differentiation was also inhibited.

CONCLUSIONThe monocytic differentiation of HL60 cells induced by NSC67657 may not be via the regulation by C/EBPalpha protein-mediated signal transduction. However, the overexpression of CEBPalpha may inhibit the process of NSC67657-induced monocytic differentiation in HL60 cells.

CCAAT-Enhancer-Binding Protein-alpha ; genetics ; metabolism ; CD11b Antigen ; metabolism ; Cell Differentiation ; drug effects ; Genetic Vectors ; Granulocytes ; cytology ; HL-60 Cells ; Humans ; Lipopolysaccharide Receptors ; metabolism ; Mesylates ; pharmacology ; Monocytes ; cytology ; RNA, Messenger ; metabolism ; Recombinant Proteins ; genetics ; metabolism ; Signal Transduction ; Steroids ; pharmacology ; Transfection

OBJECTIVETo explore the biological effect on NB4 cells proliferation, all-trans retinoic acid (ATRA) inducing differentiation and resistance to apoptosis by vascular endothelial growth factor (VEGF)-C cDNA transfection.

METHODSThe recombinant eukaryotic expression plasmid pcDNA3.1-VEGF-C and the vacant pcDNA3.1 vector were introduced separately into NB4 cells by lipofectamine mediation. The positive clones were screened by G418 and identified by reverse transcriptase-PCR (RT-PCR) and Western blotting. The proliferation capacity of NB4/VEGF-C cells was analysed by MTT assay and colony forming assay in vitro. After NB4/VEGF-C cells were induced by ATRA, the expression level of C/EBPalpha gene, CD11b on cells surface and morphological alteration were analysed by real-time quantitative PCR (RQ-PCR), flow cytometry (FCM), and Wright-Giemsa staining, respectively. FCM Annexin V-FITC/PI dual labeling technique was performed to investigate the etoposide (Vp16) induced NB4/VEGF-C cells apoptosis and bcl-2 gene expression level in these cells was analysed by RQ-PCR. The NB4/pcDNA3.1 cells was used as control in the above experiments.

RESULTSA stable NB4 cell line that secrets VEGF-C and its control lines were established. The proliferation capacity of the former was stronger than that of the latter. The expression level of C/EBPalpha gene of NB4/VEGF-C cells on ATRA treatment was only 1/32 that of NB4/pcDNA3.1 cells. The CD11b level and the degree of differentiation of NB4/VEGF-C were weaker than that of NB4/pcDNA3.1 cells. The percentage of apoptotic NB4/VEGF-C cells induced by Vp16 [(7.20 +/- 2.52)%] was significantly lower than that of NB4/pcDNA3.1 cells [(16.07 +/- 3.58)%] (P = 0.005), but the bcl-2 gene expression level of NB4/VEGF-C cells is 2.28-fold that of NB4/pcDNA3.1 cells.

CONCLUSIONThe VEGF-C via VEGFR-3 signaling pathway could promote the proliferation of leukemic cells by autocrine pathway and inhibit the cell differentiation mediated by ATRA and chemotherapy-induced apoptosis. VEGF-C/VEGFR-3 signaling loops might play an important role in disease progression and be potential therapeutic target for the treatment of leukemias.

Apoptosis ; drug effects ; genetics ; physiology ; Blotting, Western ; CCAAT-Enhancer-Binding Protein-alpha ; genetics ; metabolism ; CD11b Antigen ; genetics ; metabolism ; Cell Differentiation ; genetics ; physiology ; Cell Line, Tumor ; Cell Proliferation ; DNA, Complementary ; genetics ; Drug Resistance, Neoplasm ; Flow Cytometry ; Genetic Vectors ; Humans ; Leukemia, Promyelocytic, Acute ; genetics ; metabolism ; pathology ; Reverse Transcriptase Polymerase Chain Reaction ; Transfection ; Tretinoin ; pharmacology ; Vascular Endothelial Growth Factor C ; genetics ; metabolism ; physiology

OBJECTIVETo investigate the effects of ghrelin on the proliferation and differentiation of 3T3-L1 preadipocyte, and study the possible mechanisms.

METHODS3T3-L1 preadipocytes were cultured in vitro. The proliferation potentials of 3T3-L1 preadipocytes that were treated with different concentrations of ghrelin were evaluated by MTT methods. The levels of c-myc and thymidine kinase mRNA were detected using RT-PCR. 3T3-L1 preadipocytes were differentiated into the matured adipocytes with insulin (INS) or ghrelin. The morphological changes of 3T3-L1 adipocytes were observed and the differentiation rate was assayed by oil-red O staining. Total RNA was extracted from adipocytes at various times, and the levels of peroxisome proliferation activated receptor gamma (PPARgamma) and CAAT/enhancer binding protein(C/EBPalpha) mRNA expressions were detected using RT-PCR.

RESULTSGhrelin at concentrations of 10(-7) to 10(-15) mol/L significantly stimulated preadipocyte proliferation (p<0.05). The levels of c-myc and thymidine kinase mRNA significantly increased in 3T3-L1 preadipocytes with 10(-9) mol/L and 10(-11) mol/L ghrelin treatment (p<0.01). The 3T3-L1 preadipocytes treated with 10(-11) mol/L ghrelin had lots of lipid droplets in the cytoplasma, but the differentiation rate was lower than those treated with INS. Ghrelin of 10(-11) mol/L significantly increased the mRNA expression of PPARgamma and C/EBPalpha in the course of 3T3-L1 preadipocyte differentiation, compared with the normal control group (p<0.05). The PPARgamma and C/EBPalpha mRNA expression increased with the prolonged differentiation of preadipocytes induced by ghrelin or INS. There were significant differences in the levels of PPARgamma and C/EBPalpha mRNA expression between the 2nd and 8th days of differentiation(p<0.01).

CONCLUSIONSGhrelin promotes the proliferation and differentiation of 3T3-L1 preadipocytes. The proliferation of 3T3-L1 preadipocytes induced by ghrelin may be associated with increased c-myc levels. Ghrelin may promote differentiation of 3T3-L1 preadipocytes by increasing mRNA expression of PPARgamma and C/EBPalpha, thus enhances the sensitivity of adipocytes to INS.

3T3-L1 Cells ; Adipocytes ; cytology ; drug effects ; Animals ; CCAAT-Enhancer-Binding Protein-alpha ; genetics ; Cell Differentiation ; drug effects ; Cell Proliferation ; drug effects ; Genes, myc ; Ghrelin ; pharmacology ; Mice ; PPAR gamma ; genetics ; RNA, Messenger ; analysis ; Stem Cells ; cytology ; drug effects ; Thymidine Kinase ; genetics

To investigate the molecular mechanisms of all-trans retinoic acid (ATRA)-induced rig-g gene expression and to better understand the signal transduction of ATRA during acute promyelocytic leukemia (APL) cell differentiation, the luciferase reporter assay, co-immunoprecipitation and chromatin immunoprecipitation were used to clarify the basic transcriptional factors, which directly initiated the expression of rig-g gene. The results showed that the expression of STAT2, IRF-9 and IRF-1 could be upregulated by ATRA with different kinetics in NB4 cells. IRF-9 was able to interact with STAT2 to form a complex, which could bind the rig-g gene promoter and trigger the rig-g expression. IRF-1 alone could also activate the reporter gene containing rig-g gene promoter, but C/EBPalpha could strongly inhibit this transcription activity of IRF-1. It is concluded that during ATRA-induced APL cell differentiation, IRF-1 is first upregulated by ATRA, and then IRF-1 increases the protein levels of IRF-9 and STAT2 with the downregulation of C/EBPalpha. The complex of IRF-9 and STAT2 is the primary transcriptional factor for rig-g gene induction. This study will be helpful for better understanding the signal transduction networks of ATRA during the course of APL cell differentiation.
CCAAT-Enhancer-Binding Protein-alpha ; metabolism ; Gene Expression Regulation, Leukemic ; drug effects ; Genes, Regulator ; drug effects ; Humans ; Interferon Regulatory Factor-1 ; metabolism ; Interferon-Stimulated Gene Factor 3, gamma Subunit ; metabolism ; Intracellular Signaling Peptides and Proteins ; genetics ; Leukemia, Promyelocytic, Acute ; genetics ; STAT2 Transcription Factor ; metabolism ; Signal Transduction ; Tretinoin ; pharmacology ; Tumor Cells, Cultured