Retinol-binding protein 4 (RBP4) is adipocyte-derived secreted adipokines and elevated RBP4 expression level was closely related to insulin resistance and type II diabetes mellitus. However, the exact mechanisms are unknown. To clarify the mechanism, RBP4 lentivirus particles were packaged to infect porcine preadipocytes. Then porcine preadipocytes were activated by insulin or induced model of insulin resistance. RBP4 interference efficiency and the gene expression of each treatment groups in PI3K/Akt pathways were examined by QRT-PCR and Western blotting. The result shows that RBP4 mRNA and protein expressions were suppressed more than 60% (P < 0.01). Furthermore, no matter under insulin stimulation or insulin resistance, RBP4 knockdown significantly increased the mRNA expressions of AKT2, PI3K, GLUT4 and IRS1 compared with the control. The protein phosphorylate levels of AKT2, PI3K, IRS1 arised, meanwhile enhanced the AKT2, PI3K, GLUT4 total protein expressions. Collectively, knockdown of RBP4 increased the insulin sensitivity through upregulated PI3K/Akt pathways related factors' expression and phosphorylation in porcine adipocytes. This research will provide a new idea to treat insulin resistance related diseases.
Adipocytes ; metabolism ; Animals ; Gene Knockdown Techniques ; Insulin Resistance ; physiology ; Phosphatidylinositol 3-Kinases ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Retinol-Binding Proteins, Plasma ; genetics ; pharmacology ; Signal Transduction ; Swine

Recently the prevalence of both asthma and obesity have increased substantially in many countries. The aim of this study was to evaluate the role of retinol-binding protein (RBP) 4 in childhood asthma and its association with atopy markers, pulmonary function, and bronchial hyperresponsiveness in relation to obesity. We studied 160 children between the ages 6 to 10 yr, including 122 asthmatics and 38 controls. The body mass index, pulmonary function tests, and methacholine challenge tests were measured on the same day. Total eosinophil count, serum total IgE, serum eosinophil cationic protein, and serum RBP4 were measured in all subjects. There was no difference in serum RBP4 levels between the asthmatics and the control group. In all subjects or subgroups, serum RBP4 was not associated with total eosinophil count, serum total IgE, serum eosinophil cationic protein, or PC20. There was no relationship between serum RBP4 and pulmonary function in female asthmatics. Forced expiratory volume in 1 second/forced vital capacity (FVC) and forced expiratory flow between 25% and 75% of FVC contributed to serum RBP4 in male asthmatics. Our findings show an association between RBP4 and pulmonary function in prepubertal male asthmatics. This relationship may indirectly affect the high prevalence of childhood asthma in males.
*Asthma/blood/immunology ; Bronchial Hyperreactivity/blood/immunology ; Bronchial Provocation Tests ; Child ; Female ; Humans ; Male ; Obesity/blood/immunology ; Retinol-Binding Proteins, Plasma/*metabolism

To prepare recombinant human retinol binding protein 4 (RBP4) by using the baculovirus expression system and to detect its immunogenicity, the fusion DNA fragment of secretory signal peptide SS64 and human RBP4 gene was subcloned into a baculovirus transfer vector pFastBac-dual(pFBd), and the corresponding recombinant transfer plasmid was transformed into E. coli strain DH10bac, after transposition recombinant shuttle bacmid was screened out. The logarithmic phase Sf9 cells were transfected with the recombinant bacmid and then the recombinant baculovirus containing hRBP4 expression box were generated. After amplification of recombinant baculovirus, the recombinant baculovirus seeds were obtained. To express human RBP4, logarithmic phase Sf9 cells were infected with the virus seeds and SDS-PAGE and Western blotting were used to detect and identify the expression. Finally, to prepare a batch of RBP4 protein, logarithmic phase Sf9 cells in suspension culture were infected with recombinant baculovirus seeds and the supernatant was harvested after 120 hours post-infection for purification. Finally for preparation of polyclonal antibody and evaluation of immunogenicity, the recombinant hRBP4 from insect cells and from E. coli were immunized rabbits. Restriction enzyme digestion and sequencing confirmed that the recombinant baculovirus transfer plasmid was constructed correctly, and subsequently recombinant RBP4-bacmid was generated successfully. SDS-PAGE and Western blotting analysis suggested that human RBP4 protein was highly expressed in Sf9 cells with the molecular weight of approximately 23 kDa. The recombinant RBP4 protein could be secreted into the medium efficiently, and the expression level was calculated amount of 100 mg/L. Finally the rabbit antiserum was harvested after recombinant RBP4 immunization, therein the titer of antiserum against baculovirus recombinant RBP4 is 1:100 000 whereas the titer of antiserum against E. coli recombinant RBP4 is only 1:10 000. Overall, human RBP4 was high efficiently expressed successfully with good antigenicity in baculovirus system, and high affinity antiserum was obtained. A solid foundation was laid for the next step of the preparation of human serum RBP4 detection kit.
Animals ; Baculoviridae ; genetics ; Blotting, Western ; Cloning, Molecular ; Electrophoresis, Polyacrylamide Gel ; Escherichia coli ; Genetic Vectors ; Humans ; Immune Sera ; Insecta ; Rabbits ; Recombinant Proteins ; biosynthesis ; immunology ; Retinol-Binding Proteins, Plasma ; biosynthesis ; immunology ; Sf9 Cells ; metabolism ; Transfection

Our goal is to decipher which DNA sequences are required for tissue-specific expression of epididymal genes. At least 6 epididymis-specific lipocalin genes are known. These are differently regulated and regionalized in the epididymis. Lipocalin 5 (Lcn5 or mE-RABP) and Lipocalin 8 (Lcn8 or mEP17) are homologous genes belonging to the epididymis-specific lipocalin gene cluster. Both the 5 kb promoter fragment of the Lcn5 gene and the 5.3 kb promoter fragment of the Lcn8 gene can direct transgene expression in the epididymis (Lcn5 to the distal caput and Lcn8 to the initial segment), indicating that these promoter fragments contain important cis-regulatory element(s) for epididymis-specific gene expression. To define further the fragments regulating gene expression, the Lcn5 promoter was examined in transgenic mice and immortalized epididymal cell lines. After serial deletion, the 1.8 kb promoter fragment of the Lcn5 gene was sufficient for tissue-specific and region-specific gene expression in transgenic mice. Transient transfection analysis revealed that a transcription factor forkhead box A2 (Foxa2) interacts with androgen receptor and binds to the 100 bp fragment of the Lcn5 promoter between 1.2 kb and 1.3 kb and that Foxa2 expression inhibits androgen-dependent induction of the Lcn5 promoter activity. Immunohistochemistry indicated a restricted expression of Foxa2 in the epididymis where endogenous Lcn5 gene expression is suppressed and that the Foxa2 inhibition of the Lcn5 promoter is consistent with the lack of expression of Lcn5 in the corpus and cauda. Our approach provides a basic strategy for further analysis of the epididymal lipocalin gene regulation and flexible control of epididymal function.
Animals ; Base Sequence ; Carrier Proteins ; genetics ; Epididymis ; physiology ; Hepatocyte Nuclear Factor 3-beta ; genetics ; Humans ; Lipocalins ; Male ; Mice ; Molecular Sequence Data ; Multigene Family ; Promoter Regions, Genetic ; Prostate ; physiology ; Receptors, Retinoic Acid ; genetics ; Retinol-Binding Proteins, Plasma

Metabolic syndrome is an important long term complication in chronic asymptomatic HIV-infected subjects under highly active antiretroviral therapy (HAART), because it can contribute to morbidity and mortality via cardiovascular disease (CVD). Therefore, a predictive marker for early detection of metabolic syndrome may be necessary to prevent CVD in HIV-infected subjects. Retinol-binding protein-4 (RBP-4) has been shown to be associated with metabolic syndrome in various non-HIV-infected populations. We performed a cross-sectional study to evaluate whether serum RBP-4 levels are correlated with metabolic syndrome in HIV-infected subjects receiving HAART. In total, 98 HIV-infected Koreans who had been receiving HAART for at least 6 months were prospectively enrolled. Metabolic syndrome was diagnosed according to the Adult Treatment Panel III criteria, and serum RBP-4 concentrations were measured using human RBP-4 sandwich enzyme-linked immunosorbent assay. Serum RBP-4 levels were significantly higher in HIV-infected subjects receiving HAART with metabolic syndrome (n=33, 33.9+/-7.7 microg/mL) than in those without it (n=65, 29.9+/-7.2 microg/mL) (p=0.012). In multivariate linear regression analysis, the number of components of metabolic syndrome presented and waist circumference were independently, significantly correlated with RBP-4 (p=0.018 and 0.030, respectively). In conclusion, we revealed a strong correlation between RBP-4 and the number of components of metabolic syndrome in HIV-infected subjects receiving HAART.
Adult ; *Antiretroviral Therapy, Highly Active ; Enzyme-Linked Immunosorbent Assay ; Female ; HIV Infections/*blood/*drug therapy ; Humans ; Male ; Metabolic Syndrome X/*blood/*drug therapy ; Middle Aged ; Retinol-Binding Proteins, Plasma/*metabolism

PURPOSE: The aim of this study was to determine whether retinol-binding protein 4 (RBP4), adiponectin and high molecular weight (HMW) adiponectin are associated with insulin resistance (IR) and metabolic parameters in non-diabetic hypertensive patients. Also, we sought to compare the predictive values of these adipocytokines for IR in non-diabetic hypertensive patients. MATERIALS AND METHODS: Analyses of RBP4, adiponectin, and HMW adiponectin were performed on 308 non-diabetic hypertensives (148 males, age 58 +/- 10 years, 189 non-metabolic syndrome and 119 metabolic syndrome). The homeostasis model assessment (HOMA) index for IR, lipid profiles, and anthropometric measure-ments were assessed. RESULTS: There was no significant difference in RBP4 levels according to the presence of metabolic syndrome, although adiponectin and HMW adiponectin were significantly lower in metabolic syndrome. Correlation analysis of log RBP4 with IR and metabolic indices revealed that there was no significant correlation of RBP4 with waist circumference (r = 0.056, p = 0.324), HDL cholesterol (r = 0.005, p = 0.934), ApoB/ApoAI ratio (r = 0.066, p = 0.270), and the HOMA index (r = 0.017, p = 0.756). However, adiponectin and HMW adiponectin showed significant correlations with the HOMA index (r = - 0.247, p < 0.001; r = - 0.296, p < 0.001) and metabolic parameters. With IR defined as HOMA index > or = 2.5, HMW adiponectin did not demonstrate a superior predictive value for IR compared to adiponectin (AUC = 0.680 vs. 0.648, p = 0.083). The predictive value of RBP4 for IR was minimal (AUC = 0.534). CONCLUSION: RBP4 was not associated with IR or metabolic indices and the predictive value for IR was minimal in hypertensives. HMW adiponectin didn't have a superior predictive value for IR compared to adiponectin. Therefore, we can suggest that RBP4 and HMW adiponectin don't have more additive information than adiponectin in non-diabetic hypertensives.
Adiponectin/*blood ; Aged ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Hypertension/*blood/*physiopathology ; Insulin Resistance/*physiology ; Male ; Middle Aged ; Radioimmunoassay ; Retinol-Binding Proteins, Plasma/*metabolism ; Risk Factors ; Waist Circumference/physiology

OBJECTIVETo compare the effects of piglitazone and metformin on retinol-binding protein-4 (RBP-4) and adiponcetin (APN) in patients with type 2 diabetes mellitus (T2DM) complicated with Non alcohol fatty acid liver disease (NAFLD).

METHODSTotally 60 T2DM patients complicated with NAFLD were equally and randomly divided into pioglitazone group and metform group. The levels of biochemical indicators including body mass index (BMI), glucose hemoglobin A1C (GHbA1C), insulin resistance (HOMA-IR), fasting blood glucose (FBG), fasting insulin (FIns), and serum triglycerides (TG) as well as serum RBP-4 and APN level were measured pre-treatment and 12 weeks after treatments.

RESULTSAfter 12 weeks of treaments, BMI, FBG, HOMA-IR, GHbA1C, FIns, and TG decreased (all P<0.05) in both piglitazone group and metform group. APN increased (all P<0.05) in both groups. RBP-4 decreased (P<0.05) in piglitazone group. Compare with the metform group, the levels of RBP-4, FIns ,and HOMA-IR decreased and BMI increased in piglitazone group (P<0.05).

CONCLUSIONPiglitazone is superior to metoform in decreasing RBP-4 level and HOMA-IR in patients with T2DM complicated with NAFLD.

Adiponectin ; blood ; Adult ; Aged ; Diabetes Mellitus, Type 2 ; blood ; complications ; drug therapy ; Fatty Liver ; blood ; complications ; Female ; Humans ; Male ; Metformin ; pharmacology ; Middle Aged ; Retinol-Binding Proteins, Plasma ; metabolism ; Thiazolidinediones ; pharmacology

The isolated type of orofacial cleft, termed non-syndromic cleft lip with or without cleft palate (NSCL/P), is the second most common birth defect in China, with Asians having the highest incidence in the world. NSCL/P involves multiple genes and complex interactions between genetic and environmental factors, imposing difficulty for the genetic assessment of the unborn fetus carrying multiple NSCL/P-susceptible variants. Although genome-wide association studies (GWAS) have uncovered dozens of single nucleotide polymorphism (SNP) loci in different ethnic populations, the genetic diagnostic effectiveness of these SNPs requires further experimental validation in Chinese populations before a diagnostic panel or a predictive model covering multiple SNPs can be built. In this study, we collected blood samples from control and NSCL/P infants in Han and Uyghur Chinese populations to validate the diagnostic effectiveness of 43 candidate SNPs previously detected using GWAS. We then built predictive models with the validated SNPs using different machine learning algorithms and evaluated their prediction performance. Our results showed that logistic regression had the best performance for risk assessment according to the area under curve. Notably, defective variants in MTHFR and RBP4, two genes involved in folic acid and vitamin A biosynthesis, were found to have high contributions to NSCL/P incidence based on feature importance evaluation with logistic regression. This is consistent with the notion that folic acid and vitamin A are both essential nutritional supplements for pregnant women to reduce the risk of conceiving an NSCL/P baby. Moreover, we observed a lower predictive power in Uyghur than in Han cases, likely due to differences in genetic background between these two ethnic populations. Thus, our study highlights the urgency to generate the HapMap for Uyghur population and perform resequencing-based screening of Uyghur-specific NSCL/P markers.
Asian Continental Ancestry Group ; genetics ; China ; ethnology ; Cleft Lip ; genetics ; Cleft Palate ; genetics ; Genome-Wide Association Study ; Humans ; Infant ; Logistic Models ; Machine Learning ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Polymorphism, Single Nucleotide ; Retinol-Binding Proteins, Plasma ; genetics ; Risk Assessment

OBJECTIVE: To investigate the effect of Health Qigong Baduanjin on the related indexes of obese middle aged women with diabetes and to provide new ideas for the intervention treatment of diabetes. METHODS: A total of 40 middle-aged female obese diabetic patients were randomly divided into the control group and the exercise group(=20), the age was(57.2±5.4) years old. Fitness training group performed eight new Baduanjin exercises for 24 weeks of intervention, the control group did not exercise, body weight, waist circumference, body mass index (BMI), waist hip ratio (WHR), fasting blood glucose (FPG), glycosylated hemoglobin (HbAlc), triglyceride(TG), total cholesterol (TC), low density lipoprotein (LDL), high density lipoprotein (HDL) levels and serum retinol binding protein 4(RBP4) index were observed in the two groups. RESULTS: After exercise, the waist, WHR, FPG, TG, HbAlc, HDL and RBP4 levels of the the patients in the experimental group were decreased significantly compared with those of before exercise and those of the patients in the experimental control group before and after exercise (<0.05). CONCLUSIONS Health Qigong Baduanjin can reduce the blood sugar of obese female patients with diabetes, and has some improvement effect on the body part of obesity and blood lipid indicators.
Blood Glucose ; analysis ; Body Mass Index ; Diabetes Mellitus ; therapy ; Female ; Hemoglobins ; analysis ; Humans ; Lipids ; blood ; Middle Aged ; Obesity ; complications ; therapy ; Qigong ; Retinol-Binding Proteins, Plasma ; analysis ; Waist Circumference ; Waist-Hip Ratio

OBJECTIVE: To determine the relation between serum concentration of retinol binding protein (RBP) 4 and markers of bone metabolism, bone mineral density (BMD) in patients with type 2 diabetes mellitus (T2DM). METHODS: A total of 82 patients newly diagnosed with T2DM and 46 subjects with normal glucose tolerance (NGT) enrolled in the cross-sectional study. Subset analyses were performed, dividing subjects on the basis of gender into M-T2DM, F-T2DM, M-NGT, and F-NGT. The serum concentrions of RBP4, osteocalcin (OC) and C-terminal telopeptide of collagen type I (CTX) were measured with ELISA. The BMD was measured by dual-energy X-ray absorptiometry (DXA) with a Hologic QDR4500A device. RESULTS: In both the T2DM groups, lnRBP4 showed a positive relationship with lnCTX (M-T2DM, r=0.564, P<0.01; F-T2DM, r=0.386, P=0.018), but no association with lnOC. After adjusting for age, smoking, creatinine clearance rate (CCr), and waist-to-hip ratio (WHR), lnRBP4 still showed a strong association with lnCTX in the M-T2DM group (r'=0.536, P<0.01), but not in F-T2DM (r'=0.317, P=0.072). In the NGT group, there was no relation between lnRBP4 and lnCTX or lnOC. LnRBP4 showed no association with BMD in all groups. CONCLUSION The level of serum RBP4 may be correlated with the bone metabolism in patients with T2DM.
Adult ; Aged ; Bone Density ; Bone and Bones ; metabolism ; Collagen Type I ; blood ; Cross-Sectional Studies ; Diabetes Mellitus, Type 2 ; blood ; metabolism ; Female ; Humans ; Male ; Middle Aged ; Osteocalcin ; blood ; Peptides ; blood ; Retinol-Binding Proteins, Plasma ; metabolism