ABSTRACT
The study was done to investigate the effects of cyclical changes of endogenous sex hormones during different phases of menstrual cycle on Acylation stimulating Protein (ASP) and its correlation with lipid profile parameters in healthy reproductive women. Twenty nine healthy reproductive women with regular menstrual cycles were included in this longitudinal study. The levels of FSH, LH, progesterone and estradiol were measured along with ASP. The total cholesterol, triglycerides, HDL-C, LDLC levels were estimated during follicular, ovulatory and luteal phases of the menstrual cycle. There was a significant rise in ASP levels during luteal phase when compared to follicular phase (P<0.01). The rise in ASP levels during the luteal phase correlated with elevated progesterone levels (r=0.472, p=0.027). Multiple regression analysis including all measured variables in the study showed that progesterone was the only significant predictor of ASP levels. The level of LDL-C as well as total cholesterol/ HDL-C and LDL-C/HDL-C ratios showed significant decreases during the luteal phase compared with the follicular phase (P<0.05). No correlation was seen between ASP levels and the lipid profile parameters. The findings of this study suggest that adipokines such as ASP levels are increased during luteal phase associated with elevated progesterone levels which may contribute to increased fat storage & distribution in women of reproductive age.
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Objective To investigate the relationship between a novel polymorphism of C5L2 gene and type 2 diabetes mellitus (T2DM) in Uygur population from Xinjiang region.Methods A novel single nucleotide polymorphism(SNP),698C＞T(P233L) was found using a polymerase chain reaction direct-sequencing method.C5L2 gene 698C ＞ T variant from 252 patients with T2DM and 747 healthy control subjects was detected by polymerase chain reaction and restriction fragment length polymorphism.Result Heterozygote carriers of the 698CT genotype were more frequent among T2DM patients than that among controls (0.107 vs 0.036,x2 =18.576,P＜0.01) in the Uygur population. After adjustment of confounding factors such as sex,age,smoking,alcohol consumption,and hypertension,as well as serum levels of triglyceride,total cholesterol,low-density lipoproteincholesterol,and high-density lipoprotein-cholesterol,the difference remained significant ( P＜0.01,OR =3.373,95％ CI 1.736-6.553 ).Conclusion The CT genotype of the C5L2 gene might be a risk factor of T2DM in Uygur nationality population in Xinjiang.
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AIM: To evaluate the potential acylation stimulating protein (ASP) resistance in both adipocytes and preadipocytes under the conditions by which insulin resistance is produced by the stimulation of free fatty acids (FFA), and to explore the mechanism of ASP resistance on post-receptor level. METHODS: 3T3-L1 preadipocytes were induced to differentiate. Then the cells were treated with oleate or palmitate at concentration of 0 mmol/L (FFA-free DMEM/F12), 0.125 mmol/L, 0.5 mmol/L or 1.0 mmol/L overnight. Glucose transport was assessed by [~3H] 2-deoxyglucose uptake to evaluate insulin resistance and ASP resistance. Both non-FFA treated and FFA treated 3T3-L1 cells were cultured with ASP at concentration of 5.0 μmol/L for 4 h, then the cell proteins were extracted, and the expressions of guanine nucleotide binding protein beta (Gβ), guanine nucleotide-binding protein alpha-q/11(Gαq/11), phosphorylated-protein kinase Cα (p-PKCα) and phosphorylated-protein kinase Cζ (p-PKCζ) were measured by Western blotting. RESULTS: Both adipocytes and preadipocytes were responsive to ASP. ASP stimulation increased glucose transport by 198% in adipocytes and by 287% in preadipocytes (P<0.01 vs PBS). FFA at concentration of 0.125 mmol/L did not change ASP-stimulated glucose transport significantly, but high dose of oleate or palmitate effectively reduced the ASP response with a significant reduction by 47% (P<0.05 for oleate) and 34% (P<0.05 for palmitate) at 1 mmol/L FFA in adipocytes. Similarly in preadipocytes, glucose uptake rates were decreased by 43% (P<0.05 for oleate) and 62% (P<0.01 for palmitate) at 1 mmol/L FFA. Effects were comparable to those obtained with insulin. After overnight incubation with oleate or palmitate in adipocytes and preadipocytes, Gβ, Gαq/11, p-PKCα and p-PKCζ were downregulated both in the absence of ASP treatment and in the presence of ASP treatment in adipocytes. At concentration of 1.0 mmol/L, oleate inhibited the expressions of ASP-induced Gβ, Gαq/11, p-PKCα and p-PKCζ in adipocytes by 47%, 44%, 39% (P<0.05, P<0.01) and 20% (P>0.05), respectively. Palmitate also effectively blocked the expressions of ASP (at concentration of 1.0 mmol/L)-induced Gβ, Gαq/11, p-PKCα and p-PKCζ by 50%, 43%, 44% and 43% (P<0.05, P<0.01) in adipocytes. In preadipocytes, oleate only inhibited ASP-induced p-PKCα and p-PKCζ significantly by 39% and 19%, respectively (P<0.05). However, overnight exposure of 3T3-L1 preadipocytes to 1 mmol/L palmitate leaded to 45%, 50%, 52% and 21% (P<0.05, P<0.01) inhibition of ASP-induced expressions of Gβ, Gαq/11, p-PKCα and p-PKCζ, respectively. CONCLUSION: Oleate and palmitate inhibit ASP-mediated stimulation of glucose transport both in adipocytes and preadipocytes. The study provides direct evidence of ASP resistance under the condition of insulin resistance induced by FFA in a cellular model. The mechanism of action involves both changes in expression of C5L2 as well as signaling parameters. Fatty acid-induced ASP resistance may contribute to the physiological abnormalities associated with insulin resistance and obesity phenotype.
ABSTRACT
Treatment of AIDS (HIV) and hepatitis C virus needs protease inhibitors (PI) to prevent viral replication. Uses of PI in therapy are usually associated with a decrease in body weight and dyslipidemia. Acylation stimulating protein (ASP) is a protein synthesized in adipocytes to increase triglycerides biosynthesis, for that the relation of PI and ASP to adipogenesis is tested in this work. ASP expression was increased during 3T3-L1 differentiation and reached a peak at day 8 with cell maturation. Addition of PI during adipocytes differentiation dose dependently and significantly (p < 0.5) inhibited the degree of triglycerides (TG) accumulation. Moreover, presence of ASP (450 ng/mL) in media significantly (p < 0.5) stimulated the degree of TG accumulation and there was additive stimulation for ASP when added with insulin (10 microgram/mL). Finally, when ASP in different doses (Low, 16.7; Medium, 45 and High, 450 ng/mL) incubated with a dose of x150 PI, ASP partially inhibited the PI-inhibited adipogenesis and TG accumulation. The results in this study show that PI inhibit lipids accumulation and confirm role of ASP in TG biosynthesis and adipogenesis.
Subject(s)
Animals , Mice , 3T3 Cells , Adipogenesis/drug effects , Gene Expression Regulation/drug effects , Hypoglycemic Agents/pharmacology , Insulin/pharmacology , Intercellular Signaling Peptides and Proteins/pharmacology , Lipid Metabolism/drug effects , Protease Inhibitors/pharmacology , Time FactorsABSTRACT
Objective To study the relationship of plasma aeylation stimulating protein (ASP) with complement C3, C-reactive protein (CRP) and blood lipid levels in women with polyeystic ovary syndrome (PCOS). Methods Thirty-four patients with PCOS were divided into two groups: obese PCOS group [body mass index (BMI)≥25 kg/m2] and non-obese PCOS group (BMI<25 kg/m2). 41 age-matched non-PCOS women were also divided into two groups: simply obese group (BMI≥25 kg/m2) and non-obese control group (BMI <25kg/m2). Plasma ASP in the 4 groups was detected by enzyme linked immunosorbent assay (ELISA) method.Complement C3 and CRP were determined by immunoturbidimetrie assay. Plasma free fatty acid (FFA)concentration was determined by colorimetric enzymatic assay, plasma triglycerides (TG) by GPO-PAP method and total cholesterol (TC) by COD-PAP method. Results The plasma ASP were significantly increased in the obese PCOS group, the non-obese PCOS group and the obese group as compared with the control group [(36.4±10.9,34.8±9.9, 35.1±14.0, 24.8±7.8) nmol/L, respectively, all P<0.05]. The concentrations of complement C3 were significantly higher in the obese PCOS group and the obese group than that in the control group [(2.2±1.2,2.5±1.5, 1.1±0.7) g/L, respectively, bothP <0.05]. The concentrations of CRP were significantly increased in the obese PCOS group, non-obese PCOS group and obese group as compared with the control group [(32.1±29.2, 30.0±24.8, 23.8±5.5, 7.5±4.8)mg/L, respectively, all P<0.05]. Univariate analysis showed that both plasma ASP and C3 were positively correlated with BMI, CRP, FFA and TG. CRP was positively correlated with BMI, FFA, TG and TC. Conclusion Plasma ASP, C3 and CRP levels in women with PCOS axe increased. They are strongly associated with disturbed lipid metabolism. The lack of association between ASP and complement C3 suggests that the conversion of C3 to ASP may be affected by other factors.
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AIM: To study the expression of three kinds of transcriptional factors PPAR?, C/EBP? and C/EBP ?mRNA during differentiation in 3T3-L1 preadipocytes induced by acylation stimulating protein. METHODS: There were three groups in the study divided by the difference differentiation inducer: (1) control group: incubating the cells without any inducer; (2) IBMX+DEX group: incubating the cells with IBMX and DEX; (3) ASP group: incubating the cells with ASP, IBMX and DEX. The insulin of the typical hormone cocktail method was taken place by ASP. 3T3-L1 preadipocytes were induced to differentiate by 50 mg/L ASP+0.5 mol/L IBMX+1.0 ?mol/L DEX. The cells were harvested on the first day, second day,4th day, 6th day and 8th day after differentiation, then the total RNA of these cells were abstracted. The transcription factors PPAR?, C/EBP?, and C/EBP? mRNA expressions were assayed by RT-PCR. RESULTS: (1) During the differentiation induced by ASP group, PPAR? mRNA expression in the 3T3-L1 cells were very low on the first day after inducing differentiation. The expression was increased lightly on the second and 4th day after inducing differentiation, and it was kept on the high level on the 6th and 8th day after induction. The C/EBP? mRNA was expressed at low level on the first day after inducing differentiation. It was increased significantly on the second day and decreased significantly on the 4th day after induction. C/EBP? mRNA was not be detected on the 6th and 8th day after induction. The expression of C/EBP? mRNA was low on the first day after inducing differentiation. It was increased on the second and 4th day after induction and it was kept on high level on the 6th and 8th day after induction. (2) During the differentiation induced by IBMX+DEX group, PPAR?, C/EBP? and C/EBP? mRNA expressions were increased at the beginning of differentiation, but the levels of expression were lower than those in ASP group. CONCLUSION: The sequential expression of these transcription factors induced by ASP may be the important mechanism for the role of ASP to induce the preadipocytes to differentiate.
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AIM: To study the role of acylation stimula ting protein (ASP) in the differentiation of 3T3-F442A preadipocytes. METHODS: Differentiation of 3T3-F442A preadipocytes was induced by ASP. The morphological changes were observed by Oil-Red O staining and the di fferentiation rate was compared. TG synthesis and TG mass in these cells were al so assayed. DNA synthesis was measured by -TdR incorporation. A typical differentiation inducer, insulin, was used as a positive control to compare thes e results. RESULTS: (1) 3T3-F442A preadipocytes were induced to differentia te by ASP alone. Fat droplets were clearly visible in the cytoplasm of 3T3-F442A cells. The differentiation rate was high (90%), but no significant difference w as observed, compared with that in insulin group (95%). (2) In ASP group, TG syn thesis and TG mass were significantly increased, both of them were higher than t hat in control group (P0.05). CONCLUSION: As a new adipocytes hormone, ASP plays an important biological role in the differentiation of preadipocytes.