Expression of adipokines and adipocytokines by epidural adipose tissue in cauda equina syndrome in dogs.

BACKGROUND: Compression of epidural adipose tissue (EAT) within the scope of cauda equina syndrome (CES) could lead to an enhanced expression of inflammatory mediators, possibly contributing to pain amplification in dogs. OBJECTIVES: To analyze expression of inflammatory adipo(-cyto)kines within the EAT of dogs with CES. ANIMALS: Client-owned dogs: 15 dogs with CES and 9 dogs euthanized for unrelated medical reasons (controls). METHODS: Prospective, experimental study. Epidural adipose tissue and subcutaneous adipose tissue were collected during dorsal laminectomy and used for real-time quantitative polymerase chain reaction. Tissue explants were cultured for measurements of inflammation-induced release of cytokines. RESULTS: Results show a CES-associated upregulation of the cytokines tumor necrosis factor alpha (TNFα: mean ± SD: 18.88 ± 11.87, 95% CI: 10.90-26.86 vs 9.66 ± 5.22, 95% CI: 5.29-14.02, *: P = .04) and interleukin- (IL-) 10 (20.1 ± 9.15, 95% CI: 14.82-25.39 vs 11.52 ± 6.82, 95% CI: 5.82-17.22, *: P = .03), whereas the expression of the adipokine leptin was attenuated in EAT of dogs with CES (3.07 ± 2.29, 95% CI: 1.80-3.34 vs 9.83 ± 8.42, 95% CI: 3.36-16.30, **: P = .007). Inflammatory stimulation of EAT explant cultures resulted in an enhanced release of IL-6 (LPS: 5491.55 ± 4438, 95% CI: 833.7-10 149; HMGB1: 1001.78 ± 522.2, 95% CI: 518.8-1485; PBS: 310.9 ± 98.57, 95% CI: 228.5-393.3, ***: P < .001). CONCLUSION AND CLINICAL IMPORTANCE: Expression profile of inflammatory adipo(-cyto)kines by EAT is influenced from compressive forces acting in dogs with CES and might contribute to amplification of pain.

Gene expression of adipokines and inflammatory cytokines in peripheral blood mononuclear cells of obese dogs.

BACKGROUND: Peripheral blood mononuclear cells (PBMCs) have been identified as a possible marker of inflammation in obesity. Understanding the expression of pro- and anti-inflammatory cytokines in PBMCs in obese dogs will help control obesity-related inflammatory diseases. OBJECTIVES: The aim of this study was to evaluate the role of PBMCs in obesity-associated chronic inflammation by analyzing the expression of adipokines and inflammatory cytokines. METHODS: Blood samples were obtained from 25 subjects and real-time quantitative polymerase chain reaction determinations were performed to quantify the gene expression levels of adipokines and inflammatory cytokines, including TNF-α, IL-17, leptin, MCP-1, and adiponectin, in the PBMCs. RESULTS: The results showed that the gene expression levels of TNF-α (p < 0.001), IL-17 (p < 0.0001), and leptin (p < 0.0001) were strongly upregulated in the PBMCs of obese dogs compared to that in non-obese dogs. CONCLUSIONS: The changes in gene expression levels of inflammation-related adipokines and pro-inflammatory cytokines occur in PBMCs, which may contribute to the low-grade chronic inflammation that is present in obesity.

Analysis of an Indian diabetes prevention programme on association of adipokines and a hepatokine with incident diabetes.

To study the association and possible predictive role of visfatin, resistin, fetuin-A and chemerin with incident type 2 diabetes (T2DM) among Asian Indians with prediabetes. Their association with insulin resistance, ß-cell function, glycaemia and anthropometry were also studied. This is a nested case-control study of a large 2-year prospective prevention trial in persons at high risk of developing T2DM. Baseline HbA1c values between 6.0% (42 mmol/mol) and 6.2% (44 mmol/mol) were chosen for this analysis (n = 144). At follow-up, persons with incident T2DM (HbA1c ≥ 6.5%, 48 mmol/mol) were grouped as cases (n = 72) and those reverted to normoglycaemia, (HbA1c < 5.7% (39 mmol/mol) as controls (n = 72). Insulin resistance showed the strongest association with incident T2DM ((Odds Ratio (OR): 23.22 [95%CI 6.36-84.77]; p < 0.0001). Baseline visfatin (OR: 6.56 [95%CI 2.21-19.5]; p < 0.001) and fetuin-A (OR: 1.01 [95%CI (1.01-1.04)]; p < 0.0001) independently contributed to the conversion of prediabetes to T2DM. The contribution was significantly higher when their elevated levels coexisted (OR: 12.63 [95%CI 3.57-44.63]; p < 0.0001). The area under the curve was 0.77 ± SE 0.4 (95%CI 0.69-0.85) and 0.80 ± SE 0.04 (95%CI 0.73-0.88) for visfatin (median 17.7 ng/ml, sensitivity and specificity: 75%, p < 0.0001) and fetuin-A (mean 236.2 µg/ml, sensitivity: 71%, specificity: 75%, p < 0.0001) respectively. Higher baseline visfatin and fetuin-A concentrations are strongly associated with incident T2DM and are predictive of future diabetes.

Physical Activity Attenuates the Obesity-Induced Dysregulated Expression of Brown Adipokines in Murine Interscapular Brown Adipose Tissue.

In recent years, brown adipose tissue (BAT), which has a high heat-producing capacity, has been confirmed to exist even in adults, and it has become a focal point for the prevention and the improvement of obesity and lifestyle-related diseases. However, the influences of obesity and physical activity (PA) on the fluid factors secreted from BAT (brown adipokines) are not well understood. In this study, therefore, we focused on brown adipokines and investigated the effects of obesity and PA. The abnormal expressions of gene fluid factors such as galectin-3 (Lgals3) and Lgals3 binding protein (Lgals3bp), whose proteins are secreted from HB2 brown adipocytes, were observed in the interscapular BAT of obese mice fed a high-fat diet for 4 months. PA attenuated the abnormalities in the expressions of these genes. Furthermore, although the gene expressions of factors related to brown adipocyte differentiation such as peroxisome proliferator-activated receptor gamma coactivator 1-α were also down-regulated in the BAT of the obese mice, PA suppressed the down-regulation of these factors. On the other hand, lipogenesis was increased more in HB2 cells overexpressing Lgals3 compared with that in control cells, and the overexpression of Lgals3bp decreased the mitochondrial mass. These results indicate that PA attenuates the obesity-induced dysregulated expression of brown adipokines and suggests that Lgals3 and Lgals3bp are involved in brown adipocyte differentiation.

A Distinctive NAFLD Signature in Adipose Tissue from Women with Severe Obesity.

Development and severity of nonalcoholic fatty liver disease (NAFLD) have been linked to obesity and white adipose tissue (WAT) dysfunction plays a key role in this relation. We compared the main features of subcutaneous (SAT) and visceral WAT (VAT) tissue dysfunction in 48 obese women without (Ob) and with NAFLD (Ob-NAFLD) undergoing bariatric surgery and matched for age, BMI and T2D status. Fat cell area, adipocyte size distribution, the degree of histological fibrosis and the mRNA expression of adipokines and genes implicated in inflammation, adipogenesis, angiogenesis, metabolism and extracellular matrix remodeling were measured by RT-qPCR in both fat depots. Ob-NAFLD group showed higher TG and lower HDL circulating levels, increased VAT fat cell area and similar WAT fibrosis in comparison with Ob group. A sPLS-DA was performed in order to identify the set of genes that better characterize the presence of NAFLD. Finally, we build a multinomial logistic model including seven genes that explained 100% of the variance in NAFLD and correctly predicted 100% of cases. Our data support the existence of distinctive NAFLD signatures in WAT from women with severe obesity. A better understanding of these pathways may help in future strategies for the prevention and treatment of NAFLD.

Systemic versus local adipokine expression differs in a combined obesity and osteoarthritis mouse model.

Osteoarthritis (OA) is a degenerative joint disease characterized by cartilage loss and reduced joint function. OA risk factors are age and obesity. Many adipokines are altered by obesity but also OA although systemic adipokine regulation in OA is not always clear. Therefore, metabolic effects of diet-induced obesity on OA development as well as the influence of obesity and OA progression on systemic vs. local adipokine expression in joints were compared. C57Bl/6-mice fed with HFD (high fat diet) or normal diet prior to destabilization of the medial meniscus (DMM) were sacrificed 4/6/8 weeks after surgery. Sera were evaluated for adiponectin, leptin, visfatin, cytokines. Liver grading and staging for non-alcoholic steatohepatitis (NASH) was performed and crown-like structures (CLS) in adipose tissue measured. OA progression was scored histologically. Adipokine-expressing cells and types were evaluated by immunohistochemistry. Time-dependent changes in DMM-progression were reflected by increased systemic adiponectin levels in DMM especially combined with HFD. While HFD increased serum leptin, DMM reduced systemic leptin significantly. OA scores correlated with bodyweight, leptin and hepatic scoring. Locally, increased numbers of adiponectin- and leptin-producing fibroblasts were observed in damaged menisci but visfatin was not changed. Local adipokine expression was independent from systemic levels, suggesting different mechanisms of action.

CTRP13 Protects H9c2 Cells Against Hypoxia/Reoxygenation (H/R)-Induced Injury Via Regulating the AMPK/Nrf2/ARE Signaling Pathway.

Myocardial infarction (MI) is identified as the myocardial necrosis due to myocardial ischemia/reperfusion (I/R) injury and remains a leading cause of mortality. C1q/TNF-related protein 13 (CTRP13) is a member of CTRP family that has been found to be involved in coronary artery disease (CAD). However, the role of CTRP13 in MI remains unclear. We aimed to explore the functional role of CTRP13 in H9c2 cells exposed to hypoxia/reoxygenation (H/R). Our results demonstrated that H/R stimulation significantly decreased the expression of CTRP13 in H9c2 cells. H/R-induced an increase in ROS production and reductions in activities of SOD and CAT were prevented by CTRP13 overexpression but were aggravated by CTRP13 silencing. Moreover, CTRP13 overexpression could reverse the inductive effect of H/R on caspase-3 activity and bax expression, as well as the inhibitory effect of H/R on bcl-2 expression in H9c2 cells. However, CTRP13 silencing presented opposite effects with CTRP13 overexpression. Furthermore, CTRP13 overexpression enhanced the H/R-stimulated the expression levels of p-AMPK and nuclear Nrf2, and Nrf2 transcriptional activity. However, inhibition of AMPK reversed the CTRP13-mediated activation of Nrf2/ARE signaling and the cardiac-protective effect in H/R-exposed H9c2 cells. Additionally, silencing of Nrf2 reversed the protective effects of CTRP13 against H/R-stimulated oxidative stress and apoptosis in H9c2 cells. Finally, recombinant CTRP13 protein attenuated myocardial I/R-induced injury in rats. Taken together, these findings indicated that CTRP13 protected H9c2 cells from H/R-stimulated oxidative stress and apoptosis via regulating the AMPK/Nrf2/ARE signaling pathway. Our results provided evidence for the therapeutic potential of CTRP13 in myocardial I/R injury.

Exploring the Crosstalk between Hydrostatic Pressure and Adipokines: An In Vitro Study on Human Osteoarthritic Chondrocytes.

Obesity is a risk factor for osteoarthritis (OA) development and progression due to an altered biomechanical stress on cartilage and an increased release of inflammatory adipokines from adipose tissue. Evidence suggests an interplay between loading and adipokines in chondrocytes metabolism modulation. We investigated the role of loading, as hydrostatic pressure (HP), in regulating visfatin-induced effects in human OA chondrocytes. Chondrocytes were stimulated with visfatin (24 h) and exposed to high continuous HP (24 MPa, 3 h) in the presence of visfatin inhibitor (FK866, 4 h pre-incubation). Apoptosis and oxidative stress were detected by cytometry, B-cell lymphoma (BCL)2, metalloproteinases (MMPs), type II collagen (Col2a1), antioxidant enzymes, miRNA, cyclin D1 expressions by real-time PCR, and ß-catenin protein by western blot. HP exposure or visfatin stimulus significantly induced apoptosis, superoxide anion production, and MMP-3, -13, antioxidant enzymes, and miRNA gene expression, while reducing Col2a1 and BCL2 mRNA. Both stimuli significantly reduced ß-catenin protein and increased cyclin D1 gene expression. HP exposure exacerbated visfatin-induced effects, which were counteracted by FK866 pre-treatment. Our data underline the complex interplay between loading and visfatin in controlling chondrocytes' metabolism, contributing to explaining the role of obesity in OA etiopathogenesis, and confirming the importance of controlling body weight for disease treatment.

Human Amniotic Epithelial Cells as a Tool to Investigate the Effects of Cyanidin 3-O-Glucoside on Cell Differentiation.

Cyanidin, a kind of anthocyanin, has been reported to have chemotherapeutic activities in humans. Human amniotic epithelial cells (hAECs) are considered a potential source of pluripotent stem cells. hAECs have been used as a novel tool in regenerative cellular therapy and cell differentiation studies. In this study, to explore the effects of cyanidin-3-O-glucoside (Cy3G) on hAECs and their mechanisms, we investigated the transcriptomic changes in the Cy3G-treated cells using microarray analysis. Among the differentially expressed genes (Fold change > 1.1; p-value < 0.05), 109 genes were upregulated and 232 were downregulated. Ratios of upregulated and downregulated genes were 0.22% and 0.47% of the total expressed genes, respectively. Next, we explored the enriched gene ontology, i.e., the biological process, molecular function, and cellular component of the 37 upregulated (>1.3-fold change) and 124 downregulated (<1.3-fold change) genes. Significantly enriched biological processes by the upregulated genes included "response to muscle activity," and the genes involved in this gene ontology (GO) were Metrnl and SRD5A1, which function in the adipocyte. On the other hand, the cell cycle biological process was significantly enriched by the downregulated genes, including some from the SMC gene family. An adipogenesis-associated gene DDX6 was also included in the cell cycle biological process. Thus, our findings suggest the prospects of Cy3G in modulating adipocyte differentiation in hAECs.

The effects of bisphenol A and bisphenol S on adipokine expression and glucose metabolism in human adipose tissue.

PURPOSE: The environmental endocrine disruptors, bisphenol A (BPA) and bisphenol S (BPS) are associated with the development of type 2 diabetes. We aim to study the effects of BPA or BPS exposure on adipokine expression in human adipose tissue and on adipocyte glucose uptake. METHODS: Human subcutaneous adipose tissue was treated for 24 or 72 h with environmentally-relevant and supraphysiological concentrations of BPA or BPS (1-104 nM). Following exposure, gene expression of proinflammatory cytokines, adipokines, and estrogen receptors was measured in adipose tissue. Glucose uptake and the insulin signalling pathway were analyzed in isolated adipocytes following adipose tissue culture with BPA for 24 h. RESULTS: Adipose tissue treated with BPA for 24 h had reduced expression of the proinflammatory genes (IL6, IL1B, TNFA) and adipokines (ADIPOQ, FABP4). BPA and BPS had no effect on the expression of other proinflammatory genes (IL33), adipokines (LEP), or receptors (ESR1, ESR2) after 72-h exposure. Adipose tissue treated with environmentally-relevant concentrations of BPA for 24 h had reduced insulin-stimulated glucose uptake, without altered gene and protein levels of key insulin signalling pathway markers. CONCLUSIONS: We found that human adipose tissue treated with environmentally-relevant concentrations of BPA for 24 h, but not BPS, reduced expression of proinflammatory genes and adipokines. Furthermore, BPA reduced glucose uptake in adipocytes independently of insulin signalling. Such mechanisms can contribute to the development of insulin resistance associated with BPA exposure.

Effects of SFRP4 overexpression on the production of adipokines in transgenic mice.

Secreted frizzled-related protein (SFRP) 4 is an extracellular antagonist of Wnt signalling that regulates adipogenesis, and is highly in the visceral adipose tissue of obese individuals. However, it is still unclear how exactly SFRP4 regulates the secretion of adipokines in the adipose tissue in vivo, an event that is closely related to the pathogenesis of obesity and insulin resistance. In this study, we generated transgenic (Tg) mice overexpressing SFRP4 in the liver and investigated SFRP4 role in adipokine secretion in mice on a regular normal diet. In Tg mice, SFRP4 protein was overexpressed in the liver, as compared to wild-type littermates (non-Tg), and released into the blood. Moreover, the size of adipocytes was smaller in the visceral adipose tissue of Tg mice compared to controls. Additionally, SFRP4 overexpression affected the expression of genes related to adipocyte differentiation, causing the upregulation of adiponectin and glucose transporter 4, and the downregulation of CCAAT/enhancer-binding protein-ß, in both visceral and subcutaneous adipose tissue. However, there was no difference in body weight or body composition between Tg and non-Tg mice. In summary, our data showed that SFRP4 overexpression altered adipocyte size and adipokine secretion, possibly affecting adipocyte differentiation, obesity, and glucose metabolism.

Collagen Stiffness and Architecture Regulate Fibrotic Gene Expression in Engineered Adipose Tissue.

Adipose tissue (AT) has a dynamic extracellular matrix (ECM) surrounding adipocytes that allows for remodeling during metabolic fluctuations. During the progression of obesity, AT has increased ECM deposition, stiffening, and remodeling, resulting in a pro-fibrotic dysfunctional state. Here, the incorporation of ethylene glycol-bis-succinic acid N-hydroxysuccinimide ester (PEGDS) allows for control over 3D collagen hydrogel stiffness and architecture to investigate its influence on adipocyte metabolic and fibrotic function. Upon stiffening and altering ECM architecture, adipocytes did not alter their expression of key adipokines, leptin, and adiponectin. However, they do increase actin cytoskeletal fiber formation, pro-fibrotic gene expression, ECM deposition, and remodeling within a stiffer, 3D collagen hydrogel. For example, COL6A3 gene expression is upregulated approximately twofold, resulting in increased deposition of pericellular collagen VI alpha 3 surrounding adipocytes. Furthermore, inhibition of actin contractility results in a reversal of pro-fibrotic gene expression and ECM deposition, indicating that adipocytes are mediating mechanical cues through actin cytoskeletal networks. This study demonstrates that ECM stiffness and architecture plays a critical regulatory role in adipocyte fibrotic function and contributes to the overall pro-fibrotic dysfunctional state of AT during the progression of obesity and AT fibrosis.

Systemic Dermatitis Model Mice Exhibit Atrophy of Visceral Adipose Tissue and Increase Stromal Cells via Skin-Derived Inflammatory Cytokines.

: Adipose tissue (AT) is the largest endocrine organ, producing bioactive products called adipocytokines, which regulate several metabolic pathways, especially in inflammatory conditions. On the other hand, there is evidence that chronic inflammatory skin disease is closely associated with vascular sclerotic changes, cardiomegaly, and severe systemic amyloidosis in multiple organs. In psoriasis, a common chronic intractable inflammatory skin disease, several studies have shown that adipokine levels are associated with disease severity. Chronic skin disease is also associated with metabolic syndrome, including abnormal tissue remodeling; however, the mechanism is still unclear. We addressed this problem using keratin 14-specific caspase-1 overexpressing transgenic (KCASP1Tg) mice with severe erosive dermatitis from 8 weeks of age, followed by re-epithelization. The whole body and gonadal white AT (GWAT) weights were decreased. Each adipocyte was large in number, small in size and irregularly shaped; abundant inflammatory cells, including activated CD4+ or CD8+ T cells and toll-like receptor 4/CD11b-positive activated monocytes, infiltrated into the GWAT. We assumed that inflammatory cytokine production in skin lesions was the key factor for this lymphocyte/monocyte activation and AT dysregulation. We tested our hypothesis that the AT in a mouse dermatitis model shows an impaired thermogenesis ability due to systemic inflammation. After exposure to 4 °C, the mRNA expression of the thermogenic gene uncoupling protein 1 in adipocytes was elevated; however, the body temperature of the KCASP1Tg mice decreased rapidly, revealing an impaired thermogenesis ability of the AT due to atrophy. Tumor necrosis factor (TNF)-α, IL-1ß and interferon (INF)-γ levels were significantly increased in KCASP1Tg mouse ear skin lesions. To investigate the direct effects of these cytokines, BL/6 wild mice were administered intraperitoneal TNF-α, IL-1ß and INF-γ injections, which resulted in small adipocytes with abundant stromal cell infiltration, suggesting those cytokines have a synergistic effect on adipocytes. The systemic dermatitis model mice showed atrophy of AT and increased stromal cells. These findings were reproducible by the intraperitoneal administration of inflammatory cytokines whose production was increased in inflamed skin lesions.

Effect of the deuterium on efficiency and type of adipogenic differentiation of human adipose-derived stem cells in vitro.

In this study, we performed an adipogenic differentiation of human adipose-derived stem cells (ADSCs) in vitro with different deuterium content (natural, low and high) in the culture medium during differentiation process with parallel analysis of the gene expression, metabolic activity and cell viability/toxicity. After ADSCs differentiation into adipocytes we have done the analysis of differentiation process efficiency and determined a type of resulting adipocytes (by morphology, gene expression, UCP1 protein detection and adipokine production analysis). We have found that high (5 × 105 ppm) deuterium content significantly inhibit in vitro adipogenic differentiation of human ADSCs compared to the groups with natural (150 ppm) and low (30 ppm) deuterium content. Importantly, protocol of differentiation used in our study leads to white adipocytes development in groups with natural (control) and high deuterium content, whereas deuterium-depleted differentiation medium leads to brown-like (beige) adipocytes formation. We have also remarked the direct impact of deuterium on the cellular survival and metabolic activity. Interesting, in deuterium depleted-medium, the cells had normal survival rate and high metabolic activity, whereas the inhibitory effect of deuterated medium on ADSCs differentiation at least was partly associated with deuterium cytotoxicity and inhibitory effect on metabolic activity. The inhibitory effect of deuterium on metabolic activity and the subsequent decrease in the effectiveness of adipogenic differentiation is probably associated with mitochondrial dysfunction. Thus, deuterium could be considered as an element that affects the substance chirality. These findings may be the basis for the development of new approaches in the treatment of obesity, metabolic syndrome and diabetes through the regulation of adipose-derived stem cell differentiation and adipocyte functions.

The Contribution of the Adipose Tissue-Liver Axis in Pediatric Patients with Nonalcoholic Fatty Liver Disease after Laparoscopic Sleeve Gastrectomy.

OBJECTIVE: To evaluate the histopathologic modifications in liver and visceral adipose tissue (VAT), and to correlate these changes with clinical measures, adipokine production, and proinflammatory cytokines in a population of adolescents with obesity with nonalcoholic fatty liver disease (NAFLD) who underwent laparoscopic sleeve gastrectomy (LSG). STUDY DESIGN: Twenty adolescents with obesity who underwent LSG and with biopsy-proven NAFLD were included. Patients underwent clinical evaluation and blood tests at baseline and 1 year after the surgical procedure. Liver and VAT specimens were processed for routine histology, immunohistochemistry, and immunofluorescence. RESULTS: In adolescents with obesity and NAFLD, hepatic histologic alterations were uncorrelated with VAT inflammation. LSG induced in both liver and VAT tissue histopathology amelioration and macrophage profile modification that were correlated with body mass index and improvement in insulin resistance. The adipokine profile in liver and VAT was associated with weight loss and histologic improvement after LSG. Serum proinflammatory cytokines were correlated with liver and VAT histopathology and IL-1ß and IL-6 levels were independently predicted by liver necroinflammatory grade. CONCLUSIONS: This study suggests a unique adipose tissue/fatty liver crosstalk in pediatric patients. LSG induces a similar pattern of histologic improvement in the liver and in VAT. Besides VAT, our results strengthen the role of the liver in adipocytokine production and its contribution to systemic inflammation in pediatric patients with NAFLD.

Role of Zinc in Zinc-α2-Glycoprotein Metabolism in Obesity: a Review of Literature.

Excessive adipose tissue promotes the manifestation of endocrine disorders such as reduction of the secretion of zinc-α2-glycoprotein (ZAG), an adipokine with anti-inflammatory and lipid-mobilizing activity. The molecular structure of this adipokine includes binding sites for zinc, a trace element with important antioxidant and immunological proprieties that also participates in energy metabolism and stimulates the function of ZAG. The objective of this review is to highlight current data on the metabolism of ZAG in obesity and the role of zinc in this process. The identified studies show that subjects with obesity have low serum concentrations of zinc and ZAG, as well as low expression of the genes encoding this protein. Thus, zinc appears to be an important regulator of the homeostasis of ZAG in the body; however, alterations in the metabolism of zinc in obesity appear to compromise the functions of ZAG. Therefore, further studies are needed to clarify the relationship between zinc and ZAG metabolism and its repercussions in obesity.

Oleic acid influences the adipogenesis of 3T3-L1 cells via DNA Methylation and may predispose to obesity and obesity-related disorders.

BACKGROUND: Adipogenesis is the process of adipocytes formation from unspecialized progenitor cells called mesenchymal stromal cells. Numerous mechanisms including epigenetic regulation modulate the correct progress of this process. Dietary exposures occurring over a specific period of time might cause long-lasting and even permanent changes in gene expression regulated by epigenetic mechanisms. For that reason, we investigated the adipogenesis of 3 T3-L1 cells with the excess of saturated and monounsaturated fatty acids and their influence on global and site-specific DNA methylation in these cells. MATERIALS AND METHODS: 3T3-L1 cells were cultured in vitro to obtain 100% of confluence, then the adipogenesis was induced by a differentiation cocktail with the addition of the excess of 0.25 mM and 0.5 mM of palmitic (16:0), stearic (18:0) and oleic (18:1n-9) acids. DNA and RNA were extracted at five-time points to assess the adipogenesis process. The phenotype of mature adipocytes (insulin sensitivity, adipokines secretion, fat content) was estimated in fully mature adipocytes. DNA methylation was investigated both during adipogenesis and in mature adipocytes. RESULTS: Oleic acids stimulated expression of C/ebpα and Pparγ, which was correlated with lower methylation levels at promoters sites. Furthermore, cells cultured with an excess of oleic acid were characterized by higher lipid accumulation rate, higher leptin, and lower adiponectin secretion. Moreover, in all experimental cells, insulin signaling and glucose utilization were impaired. CONCLUSION: Oleic acid affected the methylation of Pparγ and C/ebpα promoters, what correlated with higher expression. Furthermore, examined free fatty acids influenced the phenotype of mature adipocytes, especially insulin signaling pathway and adipokine secretion.

Vaspin is a novel target gene of hepatic CCAAT-enhancer-binding protein.

Vaspin, initially identified in visceral adipose tissue, is an adipokine, and administration of recombinant vaspin leads to lowering of the endoplasmic reticulum stress which is elevated in obesity or enhancement of insulin sensitivity. CCAAT/enhancer binding protein (C/EBP), as a basic leucine zipper transcription factor, plays a critical role in adipocyte development and glucose and lipid metabolisms in liver. The present study aimed to investigate the effect of C/EBPα on vaspin gene expression. The expression of hepatic vaspin was markedly decreased in liver-specific C/EBPα knockout mice. A reporter assay indicated that two C/EBP-responsive elements (CEBPREs) are necessary for C/EBPα-dependent induction of vaspin promoter activities. Furthermore, electrophoretic mobility shift assay showed that C/EBPα in mouse liver is capable of directly binding the two CEBPREs. These results suggest that C/EBPα positively regulates hepatic vaspin expression through two functional CEBPREs. Thus, vaspin is a novel C/EBPα target gene in the liver.

Chronopharmacology of dapagliflozin-induced antihyperglycemic effects in C57BL/6J mice.

Chronopharmacology is the study of the varying responses of drugs to changes in biological timing and endogenous periodicities. The selective sodium-glucose cotransporter 2 inhibitor, dapagliflozin, is a globally prescribed antihyperglycemic drug. Although dapagliflozin is usually administered once a day, the specific intake time is generally not mentioned. Therefore, this study aimed at investigating the diurnal effects of dapagliflozin on high-fat diet (HFD)-induced obesity in mice. Five-week-old male C57BL/6J mice were fed a normal (control) diet or HFD for 10 weeks. During the last 2 weeks, the mice were administered olive oil/ethanol emulsion or dapagliflozin (1mg/kg, p.o.) in the light or dark phase. At the end of the experiment, the mice were euthanized after an 18h fasting period, and plasma and tissue samples (epididymal white adipose tissues, liver, and kidney) were collected. Dapagliflozin administration in the light phase significantly decreased plasma glucose levels, insulin levels, adipose adipokines, and decreased the size of adipocytes, compared with the HFD group. In contrast, these parameters remained unchanged in the mice treated during the dark phase. Our data therefore suggests that dapagliflozin portrays definite chronopharmacology, which may provide valuable information on the importance of drug administration timing for maximal pharmacological effects.

Metabolic effects of antidiabetic drugs on adipocytes and adipokine expression.

Several classes of antidiabetic agents have been developed that achieve their hypoglycemic outcomes via various molecular mechanisms. Adipose tissue is a major metabolic and energy-storing tissue and plays an important role in many metabolic pathways, including insulin signaling and insulin sensitivity. Adipose tissue monitors and regulates whole body homeostasis via production and release of potent proteins, such as adipokine and adiponectin, into the circulation. Therefore, any agent that can modulate adipocyte metabolism can, in turn, affect metabolic and glucose homeostatic pathways. Antidiabetic drugs are not only recognized primarily as hypoglycemic agents but may also alter adipose tissue itself, as well as adipocyte-derived adipokine expression and secretion. In the current review, we present the major evidence concerning routinely used antidiabetic agents on adipocyte metabolism and adipokine expression.