Adipose Tissue Of Obese Mice Research Articles

Adipose extracellular signal-regulated kinase 2 protected from endothelial dysfunction and the oxidative stress of perivascular adipose tissue in obese mice

Abstract Introduction Extracellular signal-regulated kinase (ERK) modulates differentiation and maturation of adipocyte and the hypertrophy and differentiation of adipocytes affected the vascular diseases in obese. Changes in characters of adipocytes could develope the oxidative stress and inflammations. Moreover, changes in perivascular adipose tissue (PVAT) could modulate vascular tonus in obesity. However, the role of adipose ERK2 in endothelial function and characters of PVAT in obese in vivo had not been clarified, yet. Purpose This study aims to elucidate the role of the adipose ERK2 in endothelial-dependent relaxation (EDR) in mice model of obesity. The role of PVAT in EDR was also assessed. Methods and results We created adipose-specific ERK2 knock out mice (AE2KO) by crossing fatty acid binding protein 4 Cre and ERK2 flox mice and fed them with normal diet (ND) or high fat/ high sucrose diet (HFHSD) for 24 weeks. AE2KO fed with HFHSD gained more weight and revealed the heterogeneity in sizes of adipocyte in subcutaneous fat (SF). Furthermore, the mRNA levels of lipoprotein lipase, hormone-sensitive lipase, and peroxisome proliferator-activated receptor γ, which was the master genes of adipocyte differentiation, were markedly down-regulated in SF. PVAT in AE2KO with HFHSD was markedly enlarged and the mRNA expression of inflammatory adipocytokines, such as IL-1β and leptin were up-regulated. Next, we assessed EDR by acetylcholine (ACh) -induced relaxation in aortic rings with or without PVAT. EDR without PVAT was modestly decreased in AE2KO with HFHSD compared with wild type mice (WT) with HFHSD. Aortic rings with PVAT increased EDR in WT with ND. PVAT modestly decreased EDR in WT with HFHSD and mostly eliminated EDR in AE2KO with HFHSD. To assess the contraction factors released from PVAT, the solutions incubated with PVAT (SIP) were transferred to the normal aortic rings. SIP from WT with HFHSD mildly increased vascular tone and SIP from AE2KO with HFHSD further increased it. Tempol, which was superoxide scavenger, restored endothelial dysfunction with PVAT and suppressed the contraction with SIP from AE2KO with HFHSD. Fluorescence intensity of dihydroethidium stain of aorta and PVAT, which indicated that aortic and adipose superoxide production were elevated in AE2KO with HFHSD, which were mostly eliminated with tempol. Conclusions Adipose ERK2 selectively modulated differentiation in SF, suppressed the aortic oxidative stress and protected from endothelial dysfunction in obese. Moreover, adipose ERK2 suppressed the hypertrophy, inflammation, and oxidative stress of PVAT in obese. The oxidative stress with the inflammation in PVAT released vasoconstriction factors, which contributed to endothelial dysfunction in obese mice. Figure 1 Funding Acknowledgement Type of funding source: None

Воспаление при атеросклерозе: от теории к практике

Inflammation causes the formation, progression, and rupture of atherosclerotic plaques, which are an integral part of cardiovascular diseases. Numerous components are involved in the pathogenesis of atherosclerotic inflammation. Experimental studies have shown that the inflammatory subpopulation of monocytes / macrophages mainly accumulates in the atherosclerotic plaque and produces Pro-inflammatory cytokines that enhance atherogenesis. T-lymphocytes can contribute to the inflammatory processes that contribute to thrombosis by stimulating the production of collagen-destroying proteinases and a powerful procoagulant substance, tissue factor. Many research data link obesity, inflammation, and risk factors for atherosclerosis, which is a growing clinical concern given the increasing prevalence of obesity worldwide. Modulators of inflammation originating from visceral adipose tissue cause the liver to produce acute phase reagents involved in thrombosis. Additionally, levels of C-reactive protein increase with increasing levels of visceral adipose tissue. The adipose tissue of obese mice contains an increased number of macrophages and T-lymphocytes, increased activation of T-lymphocytes, and increased expression of interferon-gamma. It was found that interferon-gamma deficiency in mice reduces the production of inflammatory cytokines and the accumulation of inflammatory cells in adipose tissue. Another series of experiments on mice in vitro and in vivo confirmed that adiponectin, an adipocytokine whose plasma levels drop with obesity, acts as an endogenous anti-inflammatory modulator of both innate and acquired immunity in atherogenesis. Thus, the accumulation of experimental data confirms the key role of inflammation as a link between risk factors for atherosclerosis and the biology underlying the complications of this disease. A large Jupiter clinical trial confirms the clinical utility of assessing inflammatory status in therapeutic interventions to limit cardiovascular events. Thus, knowledge of the pathogenetic mechanisms underlying atherosclerotic inflammation is not only of theoretical value, but can also be used in practice when assessing the risk and prescribing therapy.

The Role of SHIP1 on Apoptosis and Autophagy in the Adipose Tissue of Obese Mice.

Obesity-induced adipocyte apoptosis promotes inflammation and insulin resistance. Src homology domain-containing inositol 5′-phosphatase 1 (SHIP1) is a key factor of apoptosis and inflammation. However, the role of SHIP1 in obesity-induced adipocyte apoptosis and autophagy is unclear. We found that diet-induced obesity (DIO) mice have significantly greater crown-like structures and terminal deoxynucleotidyl transferase deoxyuridine triphosphate (dUTP) nick-end labeling (TUNEL)-positive cells than ob/ob or control mice. Using RNA sequencing (RNA-seq) analysis, we identified that the apoptosis- and inflammation-related gene Ship1 is upregulated in DIO and ob/ob mice compared with control mice. In particular, DIO mice had more SHIP1-positive macrophages and lysosomal-associated membrane protein 1 (LAMP1) as well as a higher B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax)/Bcl-2 ratio compared with ob/ob or control mice. Furthermore, caloric restriction attenuated adipose tissue inflammation, apoptosis, and autophagy by reversing increases in SHIP1-associated macrophages, Bax/Bcl2-ratio, and autophagy in DIO and ob/ob mice. These results demonstrate that DIO, not ob/ob, aggravates adipocyte inflammation, apoptosis, and autophagy due to differential SHIP1 expression. The evidence of decreased SHIP1-mediated inflammation, apoptosis, and autophagy indicates new therapeutic approaches for obesity-induced chronic inflammatory diseases.

Eicosapentaenoic Acid Regulates Inflammatory Pathways through Modulation of Transcripts and miRNA in Adipose Tissue of Obese Mice

This study aims to investigate the global profiling of genes and miRNAs expression to explore the regulatory effects of eicosapentaenoic acid (EPA) in visceral adipose tissue (VAT) of obese mice. We used male mice, fed either a high-fat diet (HF) or HF supplemented with EPA (HF-EPA), for 11 weeks. RNA, and small RNA profiling, were performed by RNAseq analysis. We conducted analyses using Ingenuity Pathway Analysis software (IPA®) and validated candidate genes and miRNAs related to lipid mediators and inflammatory pathways using qRT-PCR. We identified 153 genes differentially downregulated, and 62 microRNAs differentially expressed in VAT from HF-EPA compared to HF. Genes with a positive association with inflammation, chemotaxis, insulin resistance, and inflammatory cell death, such as Irf5, Alox5ap, Tlrs, Cd84, Ccr5, Ccl9, and Casp1, were downregulated by EPA. Moreover, EPA significantly reduced LTB4 levels, a lipid mediator with a central role in inflammation and insulin resistance in obesity. The pathways and mRNA/microRNA interactions identified in our study corroborated with data validated for inflammatory genes and miRNAs. Together, our results identified key VAT inflammatory targets and pathways, which are regulated by EPA. These targets merit further investigation to better understand the protective mechanisms of EPA in obesity-associated inflammation.

Omentin-1 attenuates adipose tissue inflammation via restoration of TXNIP/NLRP3 signaling in high-fat diet-induced obese mice.

Omentin-1 is an adipokine expressed by the adipose tissue and is reduced in obesity. This study was designed to calculate the protective efficiency and mechanism of omentin-1 against inflammation of the adipose tissue in obese mice. A transgenic mouse model with omentin-1 protein overexpression was established by crossing omentin-1 transgenic mice with Fabp4-Cre mice. Obesity was induced in the mice by feeding them a high-fat diet for 10weeks. Fabp4-Cre-mediated overexpression of omentin-1 significantly increased serum omentin-1 level, serum anti-inflammatory factor levels, and expression of M2-specific mRNAs; inhibited body weight and adipose tissue weight gain; improved glucose tolerance, insulin tolerance, and insulin sensitivity; decreased serum levels of insulin and proinflammatory factors, adipocyte size, and expression of M1-specific mRNAs; suppressed macrophage infiltration; downregulated expression of proinflammatory factors; upregulated expression of anti-inflammatory factors; and inhibited thioredoxin-interacting protein (TXNIP)/NOD-like receptor 3 (NLRP3) signaling in the adipose tissue of obese mice. An NLRP3 inhibitor (20mg/kg MCC950) exhibited the same effects as overexpression of omentin-1. Pretreatment with omentin-1 inhibited lipopolysaccharide-induced inflammation via TXNIP/NLRP3 signaling in RAW 264.7 macrophages. These findings suggest that omentin-1 suppresses adipose tissue inflammation in obese mice, at least partly, via inhibiting the TXNIP/NLRP3 signaling pathway.

Plant Bioactive Molecules Reduces Endoplasmic Reticulum Stress in Liver and Adipose Tissue of Obese Mice

Abstract Objectives To determine if diferent plant bioactive compounds can ammelirate endoplasmic reticulum stress markers in liver and adipose tissue of obese mice and mice administered with a low dose of tunicamicin. Methods C57BL6 mice were fed a control diet (7% fat) or a high-fat diet (21% fat) with and without genistein or resveratrol supplementation (0.1%) for 12 weeks. Pharmacologic ER stress was induced in mice fed the control diet by an ip injection of a low dose of tunicamycin and euthanized 8 or 24 h after tunicamycin administration. Adipose tissues and liver were harvested to determine the abundance of ER stress markers by western blot and real time PCR. Results Genistein and resveratrol reduced the abundance of phospho JNK and phospho PERK in liver and subcutaneous adipose tissue of obese mice and lean mice administered with tunicamycin. Both polyphenols increased the mRNA abundance of XBP1s and BiP and reduced that of CHOP in both organs. These changes in proten phosphorylation and gene expression were accompanied with reduced hepatic steatosis and adipocyte hypertrophy. Conclusions The supplementation with plant polyphenols such as genistein or resveratrol reduced ER stress markers in liver and adipose tissue of obese mice and lean mice administerd with tunicamycin. Funding Sources This work is supported by a grant from CONACYT, Mexico to ITV Grant No. A1-S-41,077.

Homeostatic and pathogenic roles of GM3 ganglioside molecular species in TLR4 signaling in obesity

Innate immune signaling via TLR4 plays critical roles in pathogenesis of metabolic disorders, but the contribution of different lipid species to metabolic disorders and inflammatory diseases is less clear. GM3 ganglioside in human serum is composed of a variety of fatty acids, including long‐chain (LCFA) and very‐long‐chain (VLCFA). Analysis of circulating levels of human serum GM3 species from patients at different stages of insulin resistance and chronic inflammation reveals that levels of VLCFA‐GM3 increase significantly in metabolic disorders, while LCFA‐GM3 serum levels decrease. Specific GM3 species also correlates with disease symptoms. VLCFA‐GM3 levels increase in the adipose tissue of obese mice, and this is blocked in TLR4‐mutant mice. In cultured monocytes, GM3 by itself has no effect on TLR4 activation; however, VLCFA‐GM3 synergistically and selectively enhances TLR4 activation by LPS/HMGB1, while LCFA‐GM3 and unsaturated VLCFA‐GM3 suppresses TLR4 activation. GM3 interacts with the extracellular region of TLR4/MD2 complex to modulate dimerization/oligomerization. Ligand‐molecular docking analysis supports that VLCFA‐GM3 and LCFA‐GM3 act as agonist and antagonist of TLR4 activity, respectively, by differentially binding to the hydrophobic pocket of MD2. Our findings suggest that VLCFA‐GM3 is a risk factor for TLR4‐mediated disease progression.

The Effect of Silibinin on Protein Expression Profile in White Adipose Tissue of Obese Mice.

ObjectiveTo investigate the effect of silibinin on the protein expression profile of white adipose tissue (WAT) in obese mice by using Tandem Mass Tag (TMT) and liquid chromatography-tandem mass spectrometry (LC-MS/MS).MethodsAccording to experimental requirements, 36 C57BL/6JC mice were randomly divided into normal diet group (WC group), high fat diet group (WF group), and high fat diet + silibinin group (WS group). WS group was intragastrically administered with 54 mg/kg body weight of silibinin, and the WC group and the WF group were intragastrically administered with equal volume of normal saline. Serum samples were collected to detect fasting blood glucose and blood lipids. IPGTT was used to measure the blood glucose value at each time point and calculate the area under the glucose curve. TMT combined with LC-MS/MS were used to study the expression of WAT, and its cellular processes, biological processes, corresponding molecular functions, and related network molecular mechanisms were analyzed by bioinformatics. Finally, RT-PCR and LC-MS/MS were used to detect the mRNA and protein expressions of FABP5, Plin4, GPD1, and AGPAT2, respectively.ResultsAlthough silibinin did not reduce the mice's weight, it did improve glucose metabolism. In addition, silibinin decreased the concentration of TC, TG, and LDL-C and increased the concentration of HDL-C in the serum of mice. In the WF/WS group, 182 differentially expressed proteins were up-regulated and 159 were down-regulated. While in the WS/WF group, 362 differentially expressed proteins were up-regulated and 176 were down-regulated. Further analysis found that these differential proteins are mainly distributed in the peroxisome proliferation-activated receptor (PPAR), lipolysis of fat cells, metabolism of glycerides, oxidative phosphorylation, and other signaling pathways, and participate in cell processes and lipid metabolism through catalysis and integration functions. Specifically, silibinin reduced the expression of several key factors such as FABP5, Plin4, GPD1, and AGPTA2.ConclusionHigh fat diet (HFD) can increase the expression of lipid synthesis and transport-related proteins and reduce mitochondrial related proteins, thereby increasing lipid synthesis, reducing energy consumption, and improving lipid metabolism in vivo. Silibinin can reduce lipid synthesis, increase energy consumption, and improve lipid metabolism in mice in vivo.

Young Persimmon Fruit Extract Suppresses Obesity by Modulating Lipid Metabolism in White Adipose Tissue of Obese Mice.

Young persimmon fruit (YPF) has recently been reported to have a regulatory effect on lipid metabolism. The aim of this study was to investigate whether the YPF aqueous extract (YPFE) exert an antiobesity effect by modulating lipid metabolism in the white adipose tissue (WAT) of obese C57BLKS/J db/db mice. YPFE (100 or 200 mg/kg body weight/day) or distilled water as a vehicle was orally administered by gavage to 12-week-old obese male db/db mice for 3 weeks (n = 7 for each group). YPFE administration significantly reduced body weight and WAT size. Furthermore, YPFE considerably reduced triglyceride and cholesterol concentrations in serum and WAT. Obese vehicle treated mice exhibited an enhanced protein expression of adipogenic and lipogenic genes. However, this increased expression was alleviated in the YPFE-fed groups, resulting in inhibition of adipogenesis and downregulation of fatty acid synthesis. In addition, there was an increase in the level of transcription factors associated with fatty acid oxidation in the YPFE-treated group. In obese mice, the expression of proteins associated with cholesterol metabolism was augmented. YPFE did not affect cholesterol synthesis, but cholesterol efflux-related proteins were significantly upregulated. YPF exerts beneficial effects on obesity by inhibiting adipogenesis and reducing lipid synthesis and accumulation by regulation of lipid-related transcription factors in the WAT of obese mice.

Differences in macrophage polarization in the adipose tissue of obese mice under various levels of exercise intensity.

Animal studies have demonstrated that the ratio of M1 (M1Φ) to M2 (M2Φ) macrophage-specific gene expression in adipose tissue (AT) may be altered by chronic exercise; however, whether macrophage polarization is induced under these conditions has not yet been reported. Therefore, this study aimed to investigate the effect of chronic exercise on M1Φ/M2Φ polarization in the AT of high-fat diet (HFD)-induced obese mice. Exercise-induced differences in M1Φ/M2Φ polarization were verified via an exercise intensity study (EIS) in which different levels of exercise intensity were evaluated. Obesity was induced in male C57BL/6 J mice by feeding them with an HFD for 6weeks. The study consisted of four groups: control group (CON), HFD-fed group (HFD), HFD-fed with exercise group (HFD + EXE), dietary conversion from HFD to normal diet (ND) group (DC), and dietary conversion from HFD to ND group (DC + EXE). For EIS, the HFD + EXE group was divided into three subgroups: low- (LI), mid- (MI), and high- (HI) intensity exercise. The total intervention period was 8weeks. M1Φ/M2Φ polarization was confirmed by flow cytometry. M2Φ polarization in the AT of obese mice was significantly higher in HFD + EXE mice than in HFD mice, despite the HFD intake. In the EIS, M2Φ polarization was most pronounced in HFD + EXE-HI mice than in HFD mice. It can be proposed that the enhanced insulin resistance and inflammation by obesity can be improved by the increase of M2Φ polarization which is achieved by relatively high-intensity exercise.

The inhibitory effect of swimming exercise on inflammation in adipose tissue of obese mice after ovariectomy

The inhibitory effect of swimming exercise on inflammation in adipose tissue of obese mice after ovariectomy

Genistein inhibits high fat diet-induced obesity through miR-222 by targeting BTG2 and adipor1.

Obesity and diabetes mellitus have become major health problems worldwide. In recent years, genistein has been found to be capable of inhibiting obesity and alleviating insulin resistance. However, the molecular mechanism of genistein against obesity is still not fully understood. In this study, we used 3T3-L1 preadipocytes and obese mice as models to explore the molecular mechanism of genistein against obesity. We found that genistein can inhibit obesity and downregulate the expression of miR-222 in mouse adipose tissue. In 3T3-L1 preadipocytes, treatment with miR-222 inhibitor or genistein reduced the expression of miR-222 and promoted lipid decomposition, while miR-222 treatment increased the expression of miR-222 and inhibited lipolysis. Moreover, the dual-luciferase reporter assay system confirmed that BTG2 and adipor1 are the target genes of miR-222. Experiments conducted in vitro and in vivo suggest that genistein may regulate lipid metabolism in the adipose tissue of obese mice by regulating the expression of miR-222 and its target genes, BTG2 and adipor1. Our findings provide a new epigenetic mechanism underpinning the ability of genistein to resist obesity. These results may provide a reference point for the dietary treatment of obesity and type 2 diabetes mellitus.

Eosinophil Activation by Toll-Like Receptor 4 Ligands Regulates Macrophage Polarization.

Eosinophils are terminally differentiated granulocytes that have long been considered as destructive cells associated with Th2 type immune responses such as allergic inflammation and helminth infections. Recently, eosinophils have been actively studied as multifunctional leukocytes regulating an array of physiological responses through interaction with other immune cells. In this study, we examined the expression and function of Toll-like receptors (TLRs) in eosinophilic EoL-1 cells and demonstrated the expression of a number of immune mediators in activated EoL-1 cells and their interaction with the macrophage cell line THP-1 upon TLR4 ligand stimulation. EoL-1 cells differentiated with butyrate increased expression of TLR3, TLR4, and TLR7 at mRNA and protein level with flow cytometry analysis. Mature eosinophils derived from human cord blood CD34+ cells were subjected to RNA-sequencing, and showed the expression of a panel of TLR transcripts and TLR4 was the most highly expressed TLR. Among the cognate ligands of TLR3, TLR4, and TLR7, lipopolysaccharide (LPS) or palmitic acid significantly increased mRNA expression of immune mediators in differentiated EoL-1 cells. Notably, Western blot analysis of palmitic acid-treated differentiated EoL-1 cells showed significantly up-regulated expression of Th2 type cytokines and transcription factors driving eosinophil differentiation. To evaluate functional significance of TLR4 ligand-stimulated eosinophils, we added conditioned media (CM) from EoL-1 cells to differentiated THP-1 cells and assessed the expression of M1 macrophage or M2 macrophage-related markers. M1 and M2 macrophage markers were significantly upregulated by CM from LPS and palmitic acid stimulated EoL-1 cells, respectively. In addition, the adipose tissue of obese mice, where eosinophils are decreased due to obesity-induced inflammation, showed significantly decreased frequency of M2 macrophages, despite an increase in the total macrophage numbers. Based on these collective data, we proposed that eosinophils regulate both inflammatory and anti-inflammatory polarization of macrophages through functional changes induced by different TLR4 ligands.

Oral gallic acid improves metabolic profile by modulating SIRT1 expression in obese mice brown adipose tissue: A molecular and bioinformatic approach

AimsThe aim of the presente study was to examine the effects of oral gallic acid (GA) administration on the brown adipose tissue of obese mice fed with high-fat diet. New mechanisms and interactions pathways in thermogenesis were accessed through bioinformatics analyses. Main methodsSwiss male mice were divided into four groups and fed during 60 days with: standard diet, standard diet combined with gallic acid, high-fat diet and high-fat diet combined with gallic acid. Body weight, food intake, and blood parameters (glucose tolerance test, total-cholesterol, high-density low-c, triglyceride and glucose levels) were evaluated. Brown and subcutaneous white adipose tissue histological analysis were performed. SIRT1 and PGC1−α mRNA expression in the brown adipose tissue were assessed. Key findingsOur main findings showed that the gallic acid improved glucose tolerance and metabolic parameters. These results were accompanied by bioinformatics analyses that evidenced SIRT1 as main target in the thermogenesis process, confirmed as increased SIRT1 mRNA expression was evidenced in the brown adipose tissue. SignificanceTogether, the data suggest that the gallic acid effect in brown adipose tissue may improve body metabolism, glucose homeostasis and increase thermogenesis.

Liraglutide improves vascular dysfunction by regulating a cAMP-independent PKA-AMPK pathway in perivascular adipose tissue in obese mice

BackgroundPerivascular adipose tissue (PVAT) attenuates its anti-contractile effect through an endothelial-dependent mechanism that aggravates endothelial dysfunction in obesity. The present study was conducted to explore whether liraglutide could improve vascular dysfunction, including the anti-contractile effect of PVAT and endothelial function, by modulating PVAT-related signaling pathways in obesity. MethodsC57BL/6 mice were fed a normal-chow diet or a high-fat diet (HFD) with or without liraglutide treatment. Vascular function of the thoracic aorta with or without PVAT were measured. Protein levels of components of the PKA-AMPK-PGC1α and antioxidant signaling pathway in PVAT were determined by western blotting. Brown adipose tissue-related gene in PVAT was measured by qRT-PCR. ResultsMetabolic profiles of HFD-fed mice were improved after treatment with liraglutide. Liraglutide improved PVAT-induced anti-contractile capability and PVAT-induced endothelial dysfunction in HFD-fed mice both in vivo and ex vivo. However, blocking PKA, or AMPK, but not cAMP, attenuated these beneficial effects of liraglutide. Treating HFD-fed mice with liraglutide activated the AMPK/eNOS pathway and induced browning-related gene expression. Moreover, liraglutide increased antioxidant capability. The protective effects were related to activation of a cAMP-independent PKA-AMPK pathway, as demonstrated by western blot and PCR. ConclusionsLiraglutide improved vascular dysfunction by modulating a cAMP-independent PKA-AMPK pathway in PVAT in HFD-induced obese mice. The findings provide a novel mechanism for the cardiovascular protection of liraglutide by modulating PVAT function in obesity.

Electroacupuncture Reduces Body Weight by Regulating Fat Browning-Related Proteins of Adipose Tissue in HFD-Induced Obese Mice.

Objective: This study investigated the influence of electroacupuncture (EA) and its potential underlying mechanisms on adipose tissue in obese mice. Methods: Three-week-old male C56BL/6 mice were randomly divided to feed or not to feed high-fat diet (HFD), named HFD group and chow diet (CD) group, respectively. After 12 weeks, CD and HFD mice were randomly divided into two groups, respectively, to receive or not receive EA for 4 weeks. Body weight (BW) was monitored. Intraperitoneal glucose tolerance test and metabolic chamber recordings were performed. Blood samples and adipose tissue were collected for the analysis of leptin, triglyceride levels, and fat browning-related proteins. Results: EA significantly reduced food intake, BW, and white adipose tissue (WAT)/BW ratio; decreased the adipocyte size and serum concentrations of triglyceride (TG) and cholesterol; and increased oxygen consumption in HFD mice. Compared with the CD mice, the HFD mice had elevated fasting serum glucose level and impaired glucose tolerance; however, these parameters were decreased by EA treatment. Meanwhile, EA promoted the protein and mRNA expressions of UCP1, PRDM16, and PGC-1α in adipose tissue, and activated sympathetic nerves via p-TH, A2AR, and β3AR in white adipose tissue. Conclusions: EA reduced food intake, BW, TG, and cholesterol, and improved glucose tolerance in HFD mice. This ameliorative effect of EA on obesity-related symptoms associated with its promoted adipose tissue plasticity via activating sympathetic nerves.

CILP-2 is a novel secreted protein and associated with insulin resistance.

Genetic association studies have implicated that cartilage intermediate layer protein 2 (CILP-2) confers the risk susceptibility for type 2 diabetes (T2DM). However, it is still unknown whether CILP-2 is involved in the regulation of glucose homeostasis and insulin resistance (IR). In the current study, we initially observed that CILP-2 as a secreted protein was detected in both conditioned medium and lysates of cells transfected with an overexpressed vector. We then found that circulating CILP-2 levels had a progressive increase from normal to impaired glucose tolerance (a pre-diabetic status) and then to diabetes, which was correlated positively with waist-to-hip ratio, triglyceride, fasting blood glucose, 2-h blood glucose after glucose overload, HbA1c, fasting insulin, 2-h plasma insulin after glucose overload, and homeostasis model assessment of insulin resistance but negatively with HDL-C. CILP-2 expression was increased in the liver and muscle but decreased in adipose tissues of obese mice or T2DM patients. Furthermore, we demonstrated that CILP-2 circulating levels were affected by OGTT and Exenatide. CILP-2 overexpression resulted in impaired glucose tolerance and hepatic IR in vivo and increased PEPCK expression whereas suppressed phosphorylation of insulin receptor and Akt kinase in vitro. Based on these findings, we have identified a direct interaction between CILP-2 and PEPCK and suggested that CILP-2 plays an important role in the regulation of hepatic glucose production.

Effects of Vitamin D Supplementation on 1, 25-dihydroxyvitamin D Metabolism and Its Impact on Adipose Tissue Inflammation in Obese Mice (P24-004-19)

ObjectivesAdipose tissue expresses CYP27B1 and VDR, suggesting local metabolism and function of 1,25-dihydroxyvitamin D (1,25(OH)2D) in adipose tissue. Obesity has been associated with dysregulation of 1,25(OH)2D levels. We investigated effects of vitamin D supplementation on 1,25(OH)2D metabolism and its impact in adipose tissue of obese mice. MethodsSix-wk-old C57BL/6 mice were divided into 4 groups and fed experimental diets containing 10% or 45% kcal fat (CON or HFD) and differing in vitamin D content (1000 or 25,000 IU/kg of diet, DC or DS) for 13 wks. Serum 1,25(OH)2D and PTH levels were determined with radio- or enzyme-immunoassay. The mRNA levels of Cyp27b1, Cyp24a1, and Lrp2 in the kidney, and Cyp27b1, Vdr, and pro-inflammatory cytokines (Mcp-1, Rantes, Mip-1γ, Tnf-α, Il-6, Il-1β, and Ifn-γ) in the epididymal adipose tissue were determined by real-time PCR. ResultsOverall, serum 1,25(OH)2D levels were higher in DS groups compared with DC groups. When 1,25(OH)2D levels were compared between CON and HFD groups, differential pattern was observed depending on vitamin D levels in the diet. HFD-DC group showed higher serum 1,25(OH)2D and PTH levels compared with CON-DC group. However, in the DS groups, serum 1,25(OH)2D and PTH levels were not significantly affected by dietary fat amount. Renal Cyp24a1 mRNA levels, which could be up-regulated by dietary vitamin D, was higher in CON-DS group compared with CON-DC group. However, in the HFD groups, renal Cyp24a1 mRNA levels were similar in DC and DS groups. Mcp-1 and Rantes mRNA levels were higher in the HFD groups compared with CON groups, and their overall expression levels were down-regulated by vitamin D supplementation. Overall, mRNA levels of Il-6 and Il-1β were lower in the DS groups compared with DC groups. ConclusionsDietary vitamin D supplementation alleviated inflammatory responses in adipose tissue. Both 1,25(OH)2D in circulation and locally produced 1,25(OH)2D in adipose tissue might have contributed to the effect. Funding SourcesSupported by the grant from the National Research Foundation (NRF) of Korea (NRF-2018R1D1A1B070491).

OR01-3 MicroRNA-34a-Mediated FGF21 Resistance in the Adipose Tissue Contributes to Insulin Resistance and Hypoadiponectinemia in Diet-Induced Obesity

Background and Objective: Fibroblast growth factor 21 (FGF21) is a metabolic hormone with multiple beneficial effects on glucose and lipid homeostasis, in part mediated through its stimulatory effect on adiponectin secretion. However, FGF21 circulating levels are paradoxically elevated in obesity, type 2 diabetes and other obesity-related disorders, suggesting the presence of FGF21 resistance in obesity. MicroRNA-34a (miR-34a) is the most highly elevated microRNA in white adipose tissues of obese mice and a conserved miR-34a seed sequence had been detected within the 3’UTR of FGFR1 and β-klotho. Here we sought to investigate the mediatory role of miR-34a in FGF21resistance. Methods: miR-34a expression and the corresponding changes in the expression of FGFR1 and β-klotho were assessed in visceral adipose tissue from mice with or without diet-induced obesity (DIO). Luciferase assay was used to examine the binding capacity of miR-34a to the FGF21 receptor complex. The ability to reverse FGF21 resistance via inhibiting adipose miR-34a in vivo was evaluated by both lentivirus-mediated miR-34a sponge and adipose tissue specific genetic depletion. Results: A consistent elevation of miR-34a expression in the adipose tissue was observed during the development of DIO, accompanied by a progressive increase in serum FGF21 levels. Following a transient increase at 4 weeks, mRNA levels of FGFR1 and β-klotho markedly decreased with DIO, accompanied by progressive resistance to the actions of exogenous FGF21, in terms of lowering of hyperglycemia and hyperinsulinemia, and adiponectin stimulation. Site-directed mutagenesis and luciferase activity studies showed that miR-34a suppressed the expression of FGFR1 and β-klotho and also adiponectin secretion. Blocking miR-34a actions by in vivo lentivirus-mediated miR-34a sponge or adipose tissue specific gene knock-out counteracted the reduction of FGFR1 and β-klotho expressions in mice with DIO and restored the ability of FGF21 to induce adiponectin secretion in their adipose tissue. Conclusion: During the development of obesity, a progressive increase of miR-34a in visceral adipose tissue is accompanied by a decline in FGF21 sensitivity, leading to hypoadiponectinemia and insulin resistance. The possibility of selective inhibition of miR-34a in the adipose tissue, as a therapeutic approach to obesity-related metabolic disorders, warrants further investigation. Acknowledgement: This work was supported by a grant from the Health & Medical Research Fund (02132836).

Lycopene supplementation attenuates western diet-induced body weight gain through increasing the expressions of thermogenic/mitochondrial functional genes and improving insulin resistance in the adipose tissue of obese mice

This passive overconsumption of western diet has precipitated a steep rise in obesity and its comorbidities, and obesity has become one of the main threats to health worldwide. Thus, deciphering the molecular mechanisms leading to obesity is therefore of utmost importance to guide the search for novel therapeutic and preventive strategies. Lycopene (LYC), a major carotenoid present in tomato, has been regarded as a nutraceutical that has powerful anti-oxidant and anti-obesity bioactivities. Even though substantial progress has been made in deciphering the mechanism of how LYC affects obesity in recent years, whether thermogenic genes, mitochondrial function and insulin resistance are involved in the anti-obesity effect of LYC is yet to be elucidated. In the current study, we demonstrated that LYC remarkably suppressed HFFD-elevated mice body weight gain. LYC blocked lipid accumulation in adipose tissue by decreasing the expressions of lipogenesis genes and increasing the expressions of lipidolysis related genes, including thermogenic and mitochondrial functional genes. Moreover, LYC improved HFFD-induced insulin resistance in WATs via inhibiting the inflammation responses in WATs, decreasing circulating proinflammatory cytokines, suppressing gut leak and intestinal inflammation. Our study indicating that the supplementation of LYC might be a nutritional preventive strategy to combat obesity.