Anti-obesity effects of yuja (Citrus junos Sieb ex Tanaka) pomace extract fermented with lactic acid bacteria on the hepatocytes and epididymal fat tissue of rats.

This study investigated the anti-obesity effects of yuja pomace extract fermented with lactic acid bacteria in rats with high-fat diet-induced obesity over a period of eight weeks. Epididymal fat cell size was significantly smaller, by about 33%, in the treatment groups given yuja pomace extract fermented with lactic acid bacteria compared to the CON group. Electron microscopic observation of hepatocyte microstructure showed that the number of lipid droplets was lower in hepatocytes, the number of mitochondria was higher, along with distinct cristae, and the rough endoplasmic reticula were well developed with stacks of cisternae and ribosomes. Thus, it is believed that yuja pomace extract fermented with lactic acid bacteria, by influencing body weight and lipid accumulation, is effective in the prevention and treatment of obesity.

Partial Lipectomy of the Epididymal Fat Alters Expression of the Steroidogenic Enzymes in the Mouse Testis at Different Postnatal Ages.

The epididymal fat is a type of gonadal adipose tissue, which is localized closely to the testis. Even though it has been suggested that the epididymal fat is necessary for maintenance of spermatogenesis in the testis, the influence of epididymal fat on expression of testicular steroidogenic enzymes has not been examined. In the present research, expressional changes of steroidogenic enzymes in the mouse testis after 2 weeks of the surgical partial lipectomy of epididymal fat at different postnatal ages were determined by real-time polymerase chain reaction analysis. The transcript levels of all molecules at 2 months of postnatal age were significantly increased by the lipectomy of epididymal fat. However, the lipectomy at 5 months of postnatal age resulted in decreases of expression levels of all molecules examined in the testis. Except a reduced transcript level of hydroxysteroid 17-beta dehydrogenase 3, there were no significant changes of expression levels of other steroidogenic enzymes by the lipectomy at 8 months of postnatal age. At 12 months of postnatal age, the lipectomy caused a significant increase of transcript level of steroidogenic acute regulatory protein and a significant decrease of transcript level of hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerase 1, without any expressional change of cytochrome P450 side chain cleavage, hydroxysteroid 17-beta dehydrogenase 3, and hydroxysteroid 17-beta dehydrogenase 3 in the testis. These findings suggest that the substances derived from epididymal fat could differentially influence on expression of steroidogenic enzymes in the testis during postnatal period.

Expressional Evaluation of C/EBP Family, SREBP1, and Steroid Hormone Receptors in the Epididiymal Fat of Postnatally Developing Mouse.

The differentiation and development of preadipocyte into mature adipocyte are regulated by transcription factors, such as CCAAT enhancer binding protein (Cebp) gene family and sterol regulatory element binding transcription factor 1 (Srebp1). Steroid hormones give influences on the development and function of adipocyte. The present research examined expression patterns of CCAAT enhancer binding protein alpha (Cebpa), CCAAT enhancer binding protein beta (Cebpb), CCAAT enhancer binding protein gamma (Cebpg), sterol regulatory element binding transcription factor 1 (Srebp1), androgen receptor (Ar), and estrogen receptors (Esr) among different epididymal fat parts during postnatal period by quantitative real-time polymerase chain reaction. In the distal epididymal fat, expression of Cebpa, Cebpb, Cebpg, Srebp1, Ar, and Esr2 was increased until 12 months of age, while expression of Esr1 was decreased at 5 months of age and was not detectable after 8 months of age. In the proximal epididymal fat, transcript levels of Cebps and Srebp1 were increased at 8 months of age, followed by decreases of Cebpb and Cebpg transcript levels at 12 months of age. An additional increase of Srebp1 expression was observed at 12 months of age. Expression of Ar and Esr2 were increased until 8 months of age, followed by a drop of Ar expression level at 12 months of age. Expression pattern of Esr1 was similar to that in the distal epididymal fat. In the tail epididymal fat, expression of Cebpa, Cebpg, Srebp1, Ar, and Esr2 was increased with age. Esr1 was not detectable at all. The highest level of Cebpb was observed at 8 months of age. These data suggest the possibility of developmental and functional differentiation among the epididymal fat parts.

Investigation of d-allulose effects on high-sucrose diet-induced insulin resistance via hyperinsulinemic-euglycemic clamps in rats.

d-Allulose, a C-3 epimer of d-fructose, is a rare sugar that has no calories. Although d-allulose has been reported to have several health benefits, such as anti-obesity and anti-diabetic effects, there have been no reports evaluating the effects of d-allulose on insulin resistance using a hyperinsulinemic-euglycemic clamp (HE-clamp). Therefore, we investigated the effects of d-allulose on a high-sucrose diet (HSD)-induced insulin resistance model. Wistar rats were randomly divided into three dietary groups: HSD containing 5% cellulose (HSC), 5% d-allulose (HSA), and a commercial diet. The insulin tolerance test (ITT) and HE-clamp were performed after administration of the diets for 4 and 7 weeks. After 7 weeks, the muscle and adipose tissues of rats were obtained to analyze Akt signaling via western blotting, and plasma adipocytokine levels were measured. ITT revealed that d-allulose ameliorated systemic insulin resistance. Furthermore, the results of the 2-step HE-clamp procedure indicated that d-allulose reversed systemic and muscular insulin resistance. d-Allulose reversed the insulin-induced suppression of Akt phosphorylation in the soleus muscle and epididymal fat tissues and reduced plasma TNF-α levels. This study is the first to show that d-allulose improves systemic and muscle insulin sensitivity in conscious rats.

Characterization of Estrogenic Activity and Site-Specific Accumulation of Bisphenol-A in Epididymal Fat Pad: Interfering Effects on the Endocannabinoid System and Temporal Progression of Germ Cells.

The objective of this work has been to characterize the estrogenic activity of bisphenol-A (BPA) and the adverse effects on the endocannabinoid system (ECS) in modulating germ cell progression. Male offspring exposed to BPA during the foetal-perinatal period at doses below the no-observed-adverse-effect-level were used to investigate the exposure effects in adulthood. Results showed that BPA accumulates specifically in epididymal fat rather than in abdominal fat and targets testicular expression of 3ß-hydroxysteroid dehydrogenase and cytochrome P450 aromatase, thus promoting sustained increase of estrogens and a decrease of testosterone. The exposure to BPA affects the expression levels of some ECS components, namely type-1 (CB1) and type-2 cannabinoid (CB2) receptor and monoacylglycerol-lipase (MAGL). Furthermore, it affects the temporal progression of germ cells reported to be responsive to ECS and promotes epithelial germ cell exfoliation. In particular, it increases the germ cell content (i.e., spermatogonia while reducing spermatocytes and spermatids), accelerates progression of spermatocytes and spermatids, promotes epithelial detachment of round and condensed spermatids and interferes with expression of cell-cell junction genes (i.e., zonula occcludens protein-1, vimentin and ß-catenin). Altogether, our study provides evidence that early exposure to BPA produces in adulthood sustained and site-specific BPA accumulation in epididymal fat, becoming a risk factor for the reproductive endocrine pathways associated to ECS.

[Effect of acupoint thread-embedding on macrophage polarization of epididymis adipose tissue in obese mice].

OBJECTIVE: To observe the effect of acupoint thread-embedding at "Zusanli" (ST 36) and "Fenglong" (ST 40) on the macrophage polarization of epididymis adipose tissue in obese mice, and to explore the action mechanism of acupoint thread-embedding on weight control. METHODS: Among 30 male C57BL/6 mice, 10 mice were randomly selected and fed with normal diet, and the remaining 20 mice were fed with high-fat diet to establish the obesity model. Sixteen mice with successful obesity model were randomly divided into a model group and an acupoint thread-embedding group, 8 mice in each group. Eight mice were selected from mice which were fed with normal diet as the normal group. On the next day of successful modeling, acupoint thread-embedding was performed at "Zusanli" (ST 36) and "Fenglong" (ST 40) in the acupoint thread-embedding group, once every 10 days for 4 times. The body weight was recorded at 0, 8, 16, 24, 32, 40 days into intervention; the level of glucose metabolism was compared after intervention; the level of lipid metabolism and weight of epididymal adipose tissue were compared at the end of the intervention; the mRNA expression of M1 and M2 macrophage-related cytokines interleukin-10 (IL-6), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) were detected by real-time PCR; the mRNA and protein expression of M1 macrophage labeled inducible nitric oxide synthase (iNOS) and M2 macrophage labeled arginase-1 (Arg-1) were detected by real-time PCR and Western blot. RESULTS: Compared with the normal group, the body weight at 0, 8, 16, 24, 32, 40 days into intervention in the model group was increased (P<0.05); the results of glucose tolerance test at 0, 30, 60, 120 min and insulin tolerance test at 0, 30, 60, 90, 120 min in the model group were higher than those in the normal group (P<0.05); the levels of total cholesterol and triacylglycerol in the model group were significantly higher than those in the normal group (P<0.001, P<0.01); the weight of epididymal adipose tissue in the model group was significantly higher than that in the normal group (P<0.001); the mRNA expression of IL-6, MCP-1, TNF-α and iNOS was increased (P<0.05, P<0.01, P<0.001), that of IL-10, Arg-1 was decreased (P<0.01), the protein expression of iNOS was up-regulated (P<0.01), and that of Arg-1 was down-regulated (P<0.001). Compared with the model group, the body weight at 16, 24, 32, 40 days into treatment in the acupoint thread-embedding group was reduced (P<0.05); the results of glucose tolerance test at 30, 60, 120 min and insulin tolerance test at 30, 60 min in the acupoint thread-embedding group were lower than those in the model group (P<0.05); the levels of total cholesterol and triacylglycerol in the acupoint thread-embedding group were significantly lower than those in the model group (P<0.01, P<0.05); the weight of epididymal adipose tissue in the acupoint thread-embedding group was significantly lower than that in the model group (P<0.01); the mRNA expression of IL-6, MCP-1, TNF-α and iNOS was reduced (P<0.05), that of IL-10, Arg-1 was increased (P<0.05), the protein expression of iNOS was down-regulated (P<0.05), and that of Arg-1 was up-regulated (P<0.01). CONCLUSION: Acupoint thread-embedding at "Zusanli" (ST 36) and "Fenglong" (ST 40) may play a role in weight control by regulating the polarization of macrophages.

Effect of acupoint thread-embedding on macrophage polarization of epididymis adipose tissue in obese mice / 中国针灸

OBJECTIVE@#To observe the effect of acupoint thread-embedding at "Zusanli" (ST 36) and "Fenglong" (ST 40) on the macrophage polarization of epididymis adipose tissue in obese mice, and to explore the action mechanism of acupoint thread-embedding on weight control.@*METHODS@#Among 30 male C57BL/6 mice, 10 mice were randomly selected and fed with normal diet, and the remaining 20 mice were fed with high-fat diet to establish the obesity model. Sixteen mice with successful obesity model were randomly divided into a model group and an acupoint thread-embedding group, 8 mice in each group. Eight mice were selected from mice which were fed with normal diet as the normal group. On the next day of successful modeling, acupoint thread-embedding was performed at "Zusanli" (ST 36) and "Fenglong" (ST 40) in the acupoint thread-embedding group, once every 10 days for 4 times. The body weight was recorded at 0, 8, 16, 24, 32, 40 days into intervention; the level of glucose metabolism was compared after intervention; the level of lipid metabolism and weight of epididymal adipose tissue were compared at the end of the intervention; the mRNA expression of M1 and M2 macrophage-related cytokines interleukin-10 (IL-6), monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) were detected by real-time PCR; the mRNA and protein expression of M1 macrophage labeled inducible nitric oxide synthase (iNOS) and M2 macrophage labeled arginase-1 (Arg-1) were detected by real-time PCR and Western blot.@*RESULTS@#Compared with the normal group, the body weight at 0, 8, 16, 24, 32, 40 days into intervention in the model group was increased (@*CONCLUSION@#Acupoint thread-embedding at "Zusanli" (ST 36) and "Fenglong" (ST 40) may play a role in weight control by regulating the polarization of macrophages.

Expression of Adipocyte-Associated Genes in the Mouse Tail Epididymal Fat at Different Postnatal Ages.

The fat pad defined as the epididymal fat is located at the head part of the epididymis. However, another fat mass is present near the caudal epididymis, named tail epididymal fat. The present research was focused to determine the expression of adipocyte-associated molecules in the mouse tail epididymal fat at different postnatal ages, including 2, 5, 8, and 12 months of age. The quantitative real-time PCR analysis showed continuous increases of expression levels of delta like non-canonical Notch ligand 1, leptin, and resistin as postnatally aged. The transcript level of peroxisome proliferator-activated receptor gamma was the highest at 5 months of age, remaining at a steady level until 12 months of age. Expression levels of fatty acid binding protein 4, leptin, and adiponectin were significantly increased until 8 months of age, persisting the level at 12 months of age. The transcript level of fatty acid synthase was significantly increased at 8 months of age, without a further change of the level at 12 months of age. These findings exhibited the expression of adipocyte-associated genes which were also detected at the ordinary epididymal fat pad. However, expression patterns of these genes in the tail epididymal fat are different with those in the distal and proximal epididymal fat, suggesting distinct characteristics and/or functions of the tail epididymal fat.

Oral administration of Flavonifractor plautii attenuates inflammatory responses in obese adipose tissue.

Adipose tissue inflammation enhances the symptoms of metabolic syndrome. Flavonifractor plautii, a bacterium present in human feces, has been reported to participate in the metabolism of catechin in the gut. The precise function of F. plautii remains unclear. We assessed the immunoregulatory function of F. plautii both in vitro and in vivo. In vitro, we showed that both viable and heat-killed F. plautii attenuated TNF-α transcript accumulation in lipopolysaccharide-stimulated RAW 264.7 cells. For the in vivo experiment, male C57BL/6 were placed on a high-fat diet (HFD) for 11 weeks. During the final two weeks on the HFD, the animals were administered with F. plautii by once-daily oral gavage. The oral administration of F. plautii attenuated the increase in TNF-α transcription otherwise seen in the epididymal adipose tissue of HFD-fed obese mice (HFD + F. plautii). The composition of the microbial population (at the genus level) in the cecal contents of the HFD + F. plautii mice was altered considerably. In particular, the level of Sphingobium was decreased significantly, and that of Lachnospiraceae was increased significantly, in the HFD + F. plautii group. Obesity is closely associated with the development of inflammation in adipose tissue. F. plautii may be involved in inhibition of TNF-α expression in inflammatory environments. Our results demonstrated that F. plautii may be useful for alleviating the inflammatory responses of adipose tissue.

Assessment of Adipocyte Differentiation and Maturation-related Gene Expression in the Epididymal Fat of Estrogen Receptor α Knockout (ERαKO) Mouse during Postnatal Development Period.

The absence of functional estrogen receptor α (Esr1) results in an overgrowth of the epididymal fat, as observed in estrogen receptor α knockout (ERαKO) mouse. The present research was aimed to evaluate expression of various molecules associated with adipocyte differentiation and maturation in the epididymal fat of ERαKO mouse at several postnatal ages by using quantitative real-time polymerase chain reaction. The highest transcript levels of all molecules were detected at 12 months of postnatal age, except leptin which the mRNA level was increased at 5 months of age and was unchanged until 12 months of age. The expression levels of CCAAT enhancer binding protein (Cebp) alpha, androgen receptor, and lipoprotein lipase were decreased at 5 months of age but increased at about 8 months of age. The mRNA levels of Cebp gamma and sterol regulatory element binding transcription factor 1 remained steady until 8 months of age. Continuous increases of transcript levels during postnatal period were found in Cebp beta, estrogen receptor (ER) beta, fatty acid binding protein 4, and delta like non-canonical Notch ligand 1. The increases of peroxisome proliferator-activated receptor gamma and adiponectin mRNA levels were detected as early as 8 months of age. The levels of fatty acid synthase and resistin transcript at 5 and 8 months of age were lower than that at 2 months of age. These findings show the aberrant expression patterns of genes related to adipocyte differentiation and maturation in the postnatal epididymal fat pad by the disruption of ER alpha function.

A preliminary study on the differential expression of long noncoding RNAs and messenger RNAs in obese and control mice.

Obesity has become one of the public health problems that threatens children's health, but its specific etiology and pathogenesis are still unclear. Recently, many long noncoding RNAs (lncRNAs) have been shown to be involved in the occurrence of obesity. However, their roles are still poorly understood. Thus, the aim of this study was to discover the profiles of the lncRNAs and messenger RNAs (mRNAs) altered in obesity. Epididymal fat samples were collected from mice fed with control and high-fat diets (HFD) for 16 weeks to investigate the differentially expressed lncRNAs and mRNAs by lncRNA microarray, after which seven lncRNAs and nine mRNAs were validated using reverse-transcription polymerase chain reaction (RT-PCR). Bioinformatics analysis and predictions were used to determine the potential biofunctions of these differentially expressed lncRNAs. Then a coexpression network was constructed to determine the transcriptional regulatory relationship of the differentially expressed lncRNAs and mRNAs between the control and HFD groups. The body weight of the HFD group was much higher than that of the control group, as a result of the increased energy intake. In total, 8421 differentially expressed lncRNAs and 6840 mRNAs were profiled using the lncRNAs microarray. Bioinformatics predictions and the coexpression network all indicated that the occurrence of obesity was attributed to those differentially expressed lncRNAs and mRNAs associated with energy metabolism, cell differentiation, and oxidative phosphorylation. The expression levels of Cyp2e1, Atp5b, Hibch, Cnbp, Frmd6, Ptchd3, ENSMUST00000155948, AK140152, ENSMUST00000135194, and ENSMUST00000180861 were significantly different between the control and HFD groups. All these Results suggested that obesity was partially attributed to those lncRNAs associated with energy metabolism, cell differentiation, and oxidative phosphorylation.

Differential Expression of Adipocyte-Related Molecules in the Distal Epididymal Fat of Mouse during Postnatal Period.

The epididymal fat of mouse is a part of visceral fat deposit and is divided into the distal or proximal part based on its histochemical characteristics. Even though the formation of the epididymal fat pad begins before the birth, a detailed adipogenic procedure of the epididymal fat has not been revealed. The epididymal fat pad becomes enlarged and expended with age, and expressional changes of numerous genes are associated with the maturation of fat tissues. In the present research, expressional patterns of adipose tissue-related genes in the distal epididymal fat of mouse at 2, 5, 8, and 12 months of postnatal age were determined by a quantitative real-time polymerase chain reaction (PCR) analysis. The lowest transcript levels of fatty acid binding protein 4 (Fabp4), lipoprotein lipase (Lpl), delta like non-canonical Notch ligand 1 (Dlk1), peroxisome proliferator-activated receptor gamma (Pparg), leptin (Lep), adiponectin (Adipoq), and resistin (Retn) were detected at 2 months of age, except fatty acid synthase (Fasn) showing the lowest level at 5 months of age. Even though expression of Lep and Fabp4 were gradually increased until 12 months of age, significant increases of Pparg and Adipoq transcript levels were continued until 8 months of age. The transcript levels of Lpl, Rent, Dlk1, and Fasn were significantly increased at 8 months of age, compared with those at 2 months of age. The current findings suggest that the expansion of the distal epididymal fat of mouse during postnatal period would be companied with differential expression of various adipocyte-associated molecules..

MiR-27b-3p Inhibition Enhances Browning of Epididymal Fat in High-Fat Diet Induced Obese Mice.

Objective: Long-term dysregulation of energy balance is the key component of the obesity epidemic. Given the harm of central obesity and the discovery that beige cells appear within white adipose tissue (WAT), enhancing the energy-expending or "browning" ability of visceral adipose tissue (VAT) has become of therapeutic interest. In this study, we focused on the regulating role of microRNA (miRNA)-27b-3p in mice epididymal white adipose tissue (eWAT) browning. Methods: High-fat diet (HFD) induced obese mice model was constructed. Expression of miR-27b-3p and Ucp1 in eWAT was measured during the course of HFD. Through tail vein injection of antimiR-27b-3p, miR-27b-3p expression was inhibited to analyze the potential role of miR-27b-3p in fat browning and metabolism. Results: miR-27b-3p was predominantly expressed in eWAT and browning ability of eWAT in HFD induced obese mice was impaired. Inhibition of miR-27b-3p enhanced browning capacity of eWAT in mice fed an HFD and led to weight loss and insulin sensitivity improvement. Conclusions: High expression of miR-27b-3p in eWAT inhibits browning ability and leads to visceral fat accumulation. It is suggested miR-27b-3p may become a potential therapeutic option for visceral obesity and its associated diseases.

Troglitazone activates TRPV1 and causes deacetylation of PPARγ in 3T3-L1 cells.

Published research suggests that activation of transient receptor potential vanilloid subfamily 1 (TRPV1) enhances the expression and deacetylation of peroxisome proliferator-activated receptor gamma (PPARγ) to cause browning of white adipose tissue. Here, we show that TRPV1 activation by capsaicin significantly prevents high fat diet-induced obesity in mice. This is associated with an increase in the expression and deacetylation of PPARγ in the epididymal fat of these mice. Consistent with the TRPV1 activation in vivo, overexpression of TRPV1 enhanced the PPARγ and other thermogenic genes in cultured 3T3-L1 preadipocytes. To determine the interaction between TRPV1 and PPARγ signaling, we analyzed the effect of Troglitazone (Trog; a thiazolidinedione derivative and an agonist of PAARγ) treatment on cultured 3T3-L1 cells. Trog enhanced the expression of TRPV1, PPARγ and thermogenic proteins in undifferentiated 3T3-L1 cells but not in differentiated cells. Acute application of Trog stimulated a robust Ca2+ influx into 3T3-L1 cells and TRPV1 inhibition by capsazepine prevented this. More interestingly, Trog or capsaicin treatment caused the deacetylation of PPARγ in 3T3-L1 cells and inhibition of TRPV1 or Sirtuin 1 - prevented this. Our data suggest a novel effect of Trog to induce PPARγ deacetylation by activating TRPV1. This research has a significant implication on the role of TRPV1 and PPARγ signaling in the browning of white adipose tissue.

Postnatal Expressional Patterns of Adipose-Associated Molecules in the Mouse Proximal Epididymal Fat.

The epididymal fat pad is a male gonadal adipocyte tissue and is histochemically separated into distal and proximal parts. The development of epididymal fat during postnatal period has not been examined in detail. A previous research showed that expression of adipocyte-associated molecules in the distal epididymal fat of mouse is generally increased as postnatally aged. In the present study, expressional patterns of same adipocyte-associated molecules in the mouse proximal epididymal fat at 2, 5, 8, and 12 months of age were studied by quantitative real-time PCR analysis and were compared with those in the distal epididymal fat. The expressional levels of peroxisome proliferator-activated receptor gamma (Pparg), lipoprotein lipase (Lpl), and fatty acid synthase (Fasn) at 5 months of age were significantly lower than those at 2 months of age, while transcript level of leptin (Lep) at 5 months was higher than that at 2 months of age. The transcript levels of all molecules at 8 months of age were significantly increased, compared with those at 2 and 5 months of age. At 12 months of age, expression of delta like non-canonical Notch ligand 1 (Dlk1) was further significantly increased, while there was no change on the transcript level of Pparg and significant decreases of Fabp4, Retn, Lpl, Lep, Fasn, and adiponectin (Adipoq) transcript levels. The current findings show that expressional patterns of molecules associated with adipocyte in the proximal epididymal fat is somewhat different with those of the distal epididymal fat, suggesting the existence of regional variance in the epididymal fat.

Lipid-Lowering Effects of Medium-Chain Triglyceride-Enriched Coconut Oil in Combination with Licorice Extracts in Experimental Hyperlipidemic Mice.

Coconut oil has gained in popularity over recent years as a healthy oil due to its potential cardiovascular benefits. Coconut oil contains medium chain triglycerides (MCT) including lauric acid and capric acid that display beneficial properties in human health. Licorice ( Glycyrrhiza uralensis) is used as a sweetener and in traditional Chinese medicine with anti-inflammatory, antimicrobial, and antioxidant activities. This study investigated the in vivo effects of medium chain-triglycerides (MCT)-coconut oil (MCO) and its combination with licorice extract (LE-MCO) on serum lipid profile, hepatic steatosis, and local fat pad proteins in diet-induced obese mice. No liver toxicity was observed in 45% fat diet (HFD)-fed mice orally treated with LE, MCO, and LE-MCO for 12 weeks. Their supplementation reduced HFD-enhanced body weight, blood glucose, and insulin in mice. Plasma levels of both PLTP and LCAT were boosted in LE-MCO-administered mice. Supplementation of LE-MCO diminished plasma levels of TG and TC with concomitant reduction of the LDL-C level and tended to raise blood HDL-C level compared to that of HFD alone-mice. Treatment of LE-MCO encumbered the hepatic induction of hepatosteatosis-related proteins of SREBP2, SREBP1c, FAS, ACC, and CD36 in HFD-fed mice. Substantial suppression of this induction was also observed in the liver of mice treated with MCO. Oral administration of LE-MCO to HFD mice boosted hepatic activation of AMPK and the induction of UCP-1 and FATP1 in brown fat. Conversely, LE-MCO disturbed hepatic PPAR-LXR-RXR signaling in HFD-fed animals and reversed HFD-elevated epididymal PPARγ. Collectively, oral administration of LE-MCO may impede hyperlipidemia and hepatosteatosis through curtailing hepatic lipid synthesis.

Serum calcitonin gene-related peptide facilitates adipose tissue lipolysis during exercise via PIPLC/IP3 pathways.

PURPOSE: Calcitonin gene-related peptide (CGRP) is formed by alternative transcription of the calcitonin/α-CGRP gene, which also gives rise to calcitonin (CT). Recently, CGRP has been the focus of research for its metabolic effects in vitro. In the present study, the in vivo effects of CGRP on epididymal fat pads lipolysis at rest and during exercise were investigated in trained male Wistar rats. METHODS: Male Wistar rats were assigned to control and trained groups, which underwent endurance training for 12 weeks. The control (at rest) and trained (during acute exercise) animals were subjected to an intravenous injection of rat recombinant CGRP (2 µg kg-1) and CGRP-(8-37), a competitive CGRP receptors antagonist, to evaluate if and how CGRP can affect adipose tissue lipolysis at rest and during exercise. RESULTS: Intravenous injection of rat CGRP recombinant at rest upregulated major lipolysis pathways (cyclic AMP (cAMP), AMP-activated protein kinase (AMPK), and phospholipase C (PIPLC/IP3)) in fat pads, causing an elevation in plasma-free fatty acid (FFA) and a decrease in plasma triglyceride (TG). All the effects were eliminated by pretreating the animals with CGRP-(8-37), suggesting that CGRP receptors were necessary for lipolytic effects of CGRP in fat pads. In trained animals, acute exercise augmented CGRP in serum, cerebrospinal fluid (CSF), and the cortex. Pretreating the animals with CGRP-(8-37) attenuated PIPLC/IP3 pathway in fat pads and had no effect on cAMP and AMPK pathways. CONCLUSIONS: Epididymal fat pads is a metabolic target for CGRP during exercise and CGRP effects on adipose tissue metabolism during exercise could be related to PIPLC/IP3 pathway.

Inactivation of MAPK in epididymal fat and amelioration of triglyceride secretion by injection of GRK2 siRNA in ob/ob mice.

Abnormal G protein-coupled receptor kinase 2 (GRK2) accumulation has a crucial role in the development of insulin resistance and diabetes. Although GRK2 siRNA transfection in the liver improves insulin resistance-related vascular complications, the effects of GRK2 siRNA in lipid metabolism and obesity remain unknown. To investigate how GRK2 siRNA affects obesity, ob/ob mice were transfected with GRK2 siRNA, mainly in the liver, by using a hydrodynamic-based procedure. Epididymal fat, glucose, triglyceride, non-esterified fatty acid (NEFA), and alanine transaminase activity were higher in the control siRNA-transfected ob/ob mice than in the control siRNA-transfected Lean mice, but these parameters were reduced by GRK2 siRNA transfection into the ob/ob mice. GRK2 expression in epididymal fat was not altered among the 3 groups, although hepatic GRK2 expression was higher in the control siRNA-transfected ob/ob mice than in the control siRNA-transfected Lean mice. Additionally, we found that Akt interacted with GRK2 in the liver. Furthermore, phosphorylation levels of ERK1/2 and JNK were higher in the epididymal fats from the control siRNA-transfected ob/ob mice than in those from the control siRNA-transfected Lean mice, but they were lowered by transfection with GRK2 siRNA. The study results showed that GRK2 siRNA improved blood triglyceride levels and abnormal or excessive activity of mitogen-activated protein kinases in epididymal fat. This effect may be promoted by inhibition of the NEFA production pathway in the liver. Therefore, the interaction of organs (hepatic GRK2-epididymal fat) may help improve insulin resistance and diabetes-associated pathophysiology.

Expressional Patterns of Connexin Isoforms in the Rat Epididymal Fat during Postnatal Development.

In the multicellular tissue, cell-cell interaction is important for a precise control of its function. The exchange of signaling molecules between adjacent cells via connexon allows the functional harmony of cells in the tissue. The present research was to determine the presence and expressional patterns of connexin (Cx) isoforms in the rat epididymal fat during postnatal development using quantitative real-time polymerase chain reaction (PCR) analysis. Of 13 Cx isoforms examined, expression of 11 Cx isoforms in the epididymal fat during postnatal development was detected. These Cx isoforms include Cx26, Cx31, Cx31.1, Cx32, Cx33, Cx36, Cx37, Cx40, Cx43, Cx45, and Cx50. Expressional levels of all Cx isoforms at 1 and 2 years of age were significantly higher than those at the early postnatal ages, such as 7 days, 14 days, and 24 days of ages. Except Cx33 and Cx43, the transcript levels of rest Cx isoforms at 1 year of age were significantly lower than that at 2 years of age. In addition, expressional patterns of Cx isoforms between 7 days and 5 months of ages generally varied according to the isoform. The existence of various Cx isoforms in the rat epididymal fat has been identified and expression of each Cx isoform in the epididymal fat during postnatal development has shown a particular pattern, distinguishable from the others. To our knowledges, this is the first report showing expressional patterns of Cx isoforms at transcript level in the epididymal fat at various postnatal ages.

Ferroportin Expression in Adipocytes Does Not Contribute to Iron Homeostasis or Metabolic Responses to a High Calorie Diet.

BACKGROUND & AIMS: Iron has an increasingly recognized role in the regulation of adipose tissue function, including the expression of adipokines involved in the pathogenesis of nonalcoholic fatty liver disease. The cellular iron exporter, ferroportin, has been proposed as being a key determinant of adipocyte iron homeostasis. METHODS: We studied an adipocyte-specific ferroportin (Fpn1) knockout mouse model, using an Adipoq-Cre recombinase driven Fpn1 deletion and fed mice according to the fast food diet model of nonalcoholic steatohepatitis. RESULTS: We showed successful selective deletion of Fpn1 in adipocytes, but found that this did not lead to increased adipocyte iron stores as measured by atomic absorption spectroscopy or histologically quantified iron granules after staining with 3,3'-diaminobenzidine-enhanced Perls' stain. Mice with adipocyte-specific Fpn1 deletion did not show dysregulation of adiponectin, leptin, resistin, or retinol-binding protein-4 expression. Similarly, adipocyte-specific Fpn1 deletion did not affect insulin sensitivity during hyperinsulinemic-euglycemic clamp studies or lead to histologic evidence of increased liver injury. We have shown, however, that the fast food diet model of nonalcoholic steatohepatitis generates an increase in adipose tissue macrophage infiltration with crown-like structures, as seen in human beings, further validating the utility of this model. CONCLUSIONS: Ferroportin may not be a key determinant of adipocyte iron homeostasis in this knockout model. Further studies are needed to determine the mechanisms of iron metabolism in adipocytes and adipose tissue.