Signaling Pathways In Adipose Tissue Research Articles

Anti-obesity effects of Bifidobacterium lactis YGMCC2013 by promoting adipocyte thermogenesis and beige remodelling in association with gut microbiota

Obesity, a global public health challenge, is closely associated with gut microbiota alterations. Probiotics have the potential to prevent obesity, but their effectiveness can vary depending on the specific strain. This study focused on evaluating the anti-obesity and probiotic properties of four Bifidobacterium species isolated from healthy Chinese individuals in vitro. The findings indicated that Bifidobacterium lactis YGMCC2013 showed notable cholesterol assimilation ability, bile salt hydrolase activity, gastrointestinal tolerance, cellular adhesion, and production of short-chain fatty acids. The anti-obesity effect of YGMCC2013 was then assessed in mice fed a high-fat diet. The results demonstrated that YGMCC2013 reduced body and liver weight, adipose tissue hypertrophy and inflammation, and influenced specific microbial genera associated with adipose tissue characteristics. Notably, the study observed associations between certain microbial genera and different types of adipose tissue, indicating that YGMCC2013 may impact the balance and function of adipose tissue through its effects on the gut microbiota. Furthermore, YGMCC2013 enhanced the thermogenic capacity of brown and beige adipocytes, and improved the structure and function of the gut microbiota. These improvements were reflected by an increase in short-chain fatty acids produced by beneficial bacteria in the intestine, and the activation of metabolic pathways related to energy and carbohydrate metabolism. Moreover, YGMCC2013 modulated the expression of il-27 and tgr5 signaling pathways in adipose tissue, which might be involved in regulating adipose tissue inflammation and energy expenditure, respectively. These findings collectively demonstrate that YGMCC2013 has potential as a probiotic candidate for preventing obesity and improving metabolic health by influencing the gut-adipose tissue axis.

Kaempferol alleviates adipose tissue inflammation and insulin resistance in db/db mice by inhibiting the STING/NLRP3 signaling pathway.

Chronic inflammation induced by obesity plays a crucial role in the pathogenesis of insulin resistance. The infiltration of macrophages into adipose tissues contributes to adipose tissue inflammation and insulin resistance. Kaempferol, a flavonoid present in various vegetables and fruits, has been shown to possess remarkable anti-inflammatory properties. In this study, we used leptin receptor-deficient obese mice (db/db) as an insulin-resistant model and investigated the effects of kaempferol treatment on obesity-induced insulin resistance. Our findings revealed that the administration of kaempferol (50 mg/kg/day, for 6 weeks) significantly reduced body weight, fat mass, and adipocyte size. Moreover, it effectively ameliorated abnormal glucose tolerance and insulin resistance in db/db mice. In the adipose tissue of obese mice treated with kaempferol, we observed a reduction in macrophage infiltration and a downregulation of mRNA expression of M1 marker genes TNF-α and IL-1β, accompanied by an upregulation of Arg1 and IL-10 mRNA expression. Additionally, kaempferol treatment significantly inhibited the STING/NLRP3 signaling pathway in adipose tissue. In vitro experiments, we further discovered that kaempferol treatment suppressed LPS-induced inflammation through the activation of NLRP3/caspase 1 signaling in RAW 264.7 macrophages. Our results suggest that kaempferol may effectively alleviate inflammation and insulin resistance in the adipose tissue of db/db mice by modulating the STING/NLRP3 signaling pathway.

肥胖合并糖尿病中脂肪组织巨噬细胞极化相关信号通路研究进展

肥胖合并糖尿病中脂肪组织巨噬细胞极化相关信号通路研究进展

PSUN123 Increased Expression of Insulin Signaling Intermediates After Six-Months Of Medical Care In Women With Obesity And Polycystic Ovary Syndrome

Abstract Background Recently an androgen-induced obesity-independent mechanism of insulin resistance in a mouse model mimicking lean polycystic ovary syndrome (PCOS) was discovered. To date there is little to no data on the mechanism of insulin resistance or molecular insulin signaling in adipose tissue of women with PCOS undergoing Vertical Sleeve Gastrectomy (VSG). Does the mechanism of androgen receptor (AR)-mediated regulation of insulin signaling seen in the lean PCOS mouse model occur in adipose tissue of women with obesity and PCOS? Objective We hypothesize that in women with obesity and PCOS, those with higher levels of free androgen index will display more dysregulation in the insulin signaling pathway in adipose tissue. More specifically, we believe that visceral more than subcutaneous adipose tissue in the women in the study will display more dysregulation; and lastly that VSG will alleviate insulin signaling dysregulation. Briefly, insulin activates insulin receptor (IR) which leads to activation of phospho-AKT which increases phosphorylated forkhead box 01 (p-FOXO1, gluconeogenesis regulation) and transcriptionally regulates acetyl co-A carboxylase (ACC, de novo lipogenesis (DNL) regulation). Methods This is a nested mechanistic study within a randomised controlled clinical trial. We performed molecular analyses (Western blots for protein and qPRC for mRNA expression, respectively, n = 3-4/group) exploring intermediates in the insulin signaling pathway (IR, p-AKT, p-FOXO1, and ACC) in (i) visceral and subcutaneous (SubQ) adipose tissue from women with obesity and PCOS before VSG bariatric surgery (n = 3/group); and (ii) SubQ WAT from women with obesity and PCOS at baseline and six-months after medical intervention with metformin (MTF) and lifestyle modification. Results Subcutaneous (SubQ) white adipose tissue (WAT) displayed similar levels of p-ACC compared to visceral WAT from women pre-VSG. Six months of medical care increased p-ACC in SubQ WAT by 5-fold compared to baseline. IR displayed similar expression in the visceral compared to SubQ WAT in women pre-VSG. IR expression increased by 20-fold at 6-months of medical care compared to baseline in SubQ WAT. p-FOXO1 displayed similar expression in the visceral compared to SubQ WAT. However, p-FOXO1 was decreased at 6-months of medical care compared to baseline. p-AKT levels were similar in visceral compared to SubQ WAT pre-VSG. However, p-AKT levels were significantly increased by 4-fold at 6-months of medical care compared to baseline. Conclusion None of the insulin signaling intermediates measured were different in visceral compared to SubQ in women with obesity and PCOS. Additionally, the findings indicated lowered DNL, lowered regulation of gluconeogenic genes and thus lowered gluconeogenesis, and increased insulin action in SubQ WAT in women with obesity and PCOS after 6-months of medical care. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Chlorella unsaturated fatty acids suppress high-fat diet-induced obesity in C57/BL6J mice.

Chlorella has been identified as a rich source of unsaturated fatty acids. Since the antiobesity effects of unsaturated fatty acids have been well documented; therefore, we explored the antiobesity actions of chlorella unsaturated fatty acids (C.UFAs) in the current study. The obtained results demonstrated C.UFAs, which contain abundant linoleic acid, could retard body weight gain (reducing body weigh by 13.93% after 16weeks of treatment), improve blood glucose (19.29% lower) and lipid profile (23.45% lower in TG, 8.76% lower in TC) compared to high-fat diet-fed C57BL/6J mice. The possible underlying mechanisms might involve reducing hepatic lipid accumulation via down-regulation of lipogenic genes (PPARγ, C/EBPα, LPL, aP2, FAS, and SREBP-1c) and up-regulation of lipolytic gene (adiponectin). We also demonstrate C.UFAs could reduce HFD-induced adipocyte hypertrophy via activation of AMPK signaling pathway in adipose tissue and liver. In summary, our study highlights the potential of C.UFAs as a functional food for obesity management. PRACTICAL APPLICATION: Chlorella has already been commercialized as a functional food antiobesity function. In the current study, the unsaturated fatty acids isolated from chlorella were found to exert beneficial effects on hyperglycemia, hyperlipidemia, hepatic steatosis, and adipocyte hypertrophy in high-fat diet-fed mice. This may provide theoretical foundation for developing novel chlorella-based functional foods.

28-LB: Increased Expression of Insulin Signaling Intermediates after Six Months of Metformin Medical Intervention in Women with Obesity and Polycystic Ovary Syndrome

Objective: We hypothesize that in women experiencing obesity and PCOS, the women with higher levels of free androgen index will display more dysregulation in the insulin signaling pathway in adipose tissue. More specifically, we believe that visceral more than subcutaneous adipose tissue in the women in the study will display more dysregulation; and lastly that bariatric surgery will alleviate insulin signaling dysregulation. Methods: Here, we performed molecular analyses (Western blots and qPRC) exploring the insulin signaling pathway in visceral and subcutaneous (SubQ) adipose tissue from women with obesity and PCOS undergoing RYGB bariatric surgery; and SubQ WAT from women with obesity and PCOS at baseline and six-months after medical intervention with metformin (MTF) . Results: Subcutaneous (SubQ) white adipose tissue (WAT) displayed a trending (p=0.2) but non-significant increase in p-ACC compared to visceral WAT from women with PCOS and obesity pre-bariatric surgery. Six months of MTF increased p-ACC in SubQ WAT by 5-fold compared to zero months (baseline) in women with PCOS and obesity. IR displayed similar expression in the visceral compared to SubQ WAT in women with PCOS and obesity pre-bariatric surgery. IR expression increased by 20-fold at 6-months of MTF compared to baseline in SubQ WAT of women with PCOS and obesity. Phosphorylated forkhead box 01 (p-FOXO1) displayed similar expression in the visceral compared to SubQ WAT in women with PCOS and obesity. However, p-FOXO1 was decreased at 6-months of MTF compared to baseline in women with PCOS and obesity. p-AKT levels were similar in visceral compared to SubQ WAT in women with PCOS and obesity pre-bariatric surgery. However, p-AKT levels were significantly increased by 4-fold at 6-months of MTF compared to 0-months in women with PCOS and obesity. Conclusion: None of the insulin signaling intermediates measured were altered in visceral compared to SubQ in women with obesity and PCOS. Disclosure S. Andrisse: None.

Effects of nuciferine on Nrf2/HO-1 signaling pathway in adipose tissue of obesity model rats

Effects of nuciferine on Nrf2/HO-1 signaling pathway in adipose tissue of obesity model rats

Opposite Effects of Chronic Central Leptin Infusion on Activation of Insulin Signaling Pathways in Adipose Tissue and Liver Are Related to Changes in the Inflammatory Environment.

Leptin modulates insulin signaling and this involves the Akt pathway, which is influenced by changes in the inflammatory environment and with leptin regulating cytokine synthesis. We evaluated the association between activation of the insulin-signaling pathway and alterations in pro- and anti-inflammatory cytokine levels in inguinal fat and liver of chronic central leptin infused (L), pair-fed (PF), and control rats. Signal transducer and activator of transcription 3 (STAT3) phosphorylation was increased in inguinal fat and reduced in liver of L rats. Phosphorylation of c-Jun N-terminal kinase (JNK) and nuclear factor kappa B (NFkB) was increased in inguinal fat of L rats, together with a pro-inflammatory cytokine profile, while in the liver activation of JNK and NFkB were reduced and an anti-inflammatory pattern was found. Phosphorylation of the insulin receptor, Akt and mechanistic target of rapamycin was decreased in inguinal fat and increased in liver of L rats. There was a direct relationship between pSTAT3 and JNK and a negative correlation of Akt with pSTAT3 and JNK in both tissues. These results indicate that the effects of chronically increased leptin on insulin-related signaling are tissue-specific and suggest that inflammation plays a relevant role in the crosstalk between leptin and insulin signaling.

The miR-182-5p/FGF21/acetylcholine axis mediates the crosstalk between adipocytes and macrophages to promote beige fat thermogenesis.

A dynamically regulated microenvironment, which is mediated by crosstalk between adipocytes and neighboring cells, is critical for adipose tissue homeostasis and function. However, information on key molecules and/or signaling pathways regulating the crosstalk remains limited. In this study, we identify adipocyte miRNA-182-5p (miR-182-5p) as a crucial antiobesity molecule that stimulated beige fat thermogenesis by promoting the crosstalk between adipocytes and macrophages. miR-182-5p was highly enriched in thermogenic adipocytes, and its expression was markedly stimulated by cold exposure in mice. In contrast, miR-182-5p expression was significantly reduced in adipose tissues of obese humans and mice. Knockout of miR-185-5p decreased cold-induced beige fat thermogenesis whereas overexpression of miR-185-5p increased beiging and thermogenesis in mice. Mechanistically, miR-182-5p promoted FGF21 expression and secretion in adipocytes by suppressing nuclear receptor subfamily 1 group D member 1 (Nr1d1) at 5′-UTR, which in turn stimulates acetylcholine synthesis and release in macrophages. Increased acetylcholine expression activated the nicotine acetylcholine receptor in adipocytes, which stimulated PKA signaling and consequent thermogenic gene expression. Our study reveals a key role of the miR-182-5p/FGF21/acetylcholine/acetylcholine receptor axis that mediates the crosstalk between adipocytes and macrophages to promote beige fat thermogenesis. Activation of the miR-182-5p–induced signaling pathway in adipose tissue may be an effective approach to ameliorate obesity and associated metabolic diseases.

Suppression of obesity and inflammation by polysaccharide from sporoderm-broken spore of Ganoderma lucidum via gut microbiota regulation

Ganoderma lucidum has been shown to have anti-obesity effects. However, polysaccharide extracted from the sporoderm-broken spores of Ganoderma lucidum (BSGLP) against obesity and its underlying mechanisms have never been reported. In the current study, we showed that BSGLP inhibited high-fat diet (HFD)-induced obesity, hyperlipidemia, inflammation, and fat accumulation in C57BL/6 J mice. BSGLP improved HFD-induced gut microbiota dysbiosis, maintained intestinal barrier function, increased short-chain fatty acids production and GPR43 expression, ameliorated endotoxemia, manifested by reduced serum lipopolysaccharide level, and increased ileum expression of tight junction proteins and antimicrobial peptides. Fecal microbiota transplantation study confirmed that BSGLP-induced microbiota change is responsible, at least in part, for obesity inhibition. Besides, BSGLP notably alleviated HFD-induced upregulation of TLR4/Myd88/NF-κB signaling pathway in adipose tissue. Collectively, our study showed for the first time that BSGLP might be used as a prebiotic agent to inhibit obesity and hyperlipidemia through modulating inflammation, gut microbiota, and gut barrier function.

Transcriptomic changes in pancreatic islets, adipose and liver after Roux-en-Y gastric bypass in a diet-induced obese rat model

Roux-en-Y gastric bypass (RYGB) is the most efficient intervention in morbid obesity and promotes metabolic improvements in several peripheral tissues. However, the underlying molecular mechanisms are still poorly understood. To further understand the effects of RYGB on peripheral tissues transcriptomes, we determined transcriptome signatures in pancreatic islets, adipose and liver tissue from diet-induced obese (DIO) rats model following RYGB. Whereas RYGB led to discrete gene expression changes in pancreatic islets, substantial transcriptome changes were observed in metabolic and immune signaling pathways in adipose tissue and the liver, indicating major gene adaptive responses in fat-storing tissues. Compared to RYGB DIO rats, peripheral tissue transcriptome signatures were markedly different in caloric restricted weight matching DIO rats, implying that caloric restriction paradigms do not reflect transcriptomic regulations of RYGB induced weight loss. The present gene expression study may serve as a basis for further investigations into molecular regulatory effects in peripheral tissues following RYGB-induced weight loss.

Role of PDK4 in insulin signaling pathway in periadrenal adipose tissue of pheochromocytoma patients.

Studies have shown that pheochromocytoma (PHEO) is associated with glucose intolerance and decreased insulin sensitivity. In adipocytes, pyruvate dehydrogenase kinase 4 (PDK4) is involved in glucose uptake. However, very little is known about the role of PDK4 in the insulin signaling pathway in the adipose tissue of PHEO patients. We analyzed the expression of adipokines, oxidative stress-related genes, PDK4, phosphorylated AMPK (pAMPK) and phosphorylated IRS1 (pIRS1) in the periadrenal adipose tissue (peri-A) of patients with PHEO and non-functioning adrenal adenoma (NFA). We also investigated the effects of epinephrine on PDK4, pAMPK and pIRS1 in human stromal vascular fraction (SVF) cells, mouse 3T3-L1 preadipocytes and brown preadipocytes. PHEO patients had higher mRNA levels of PGC1α, C/EBPα, C/EBPβ, COXII and AP2 and lower mRNA levels of PPARγ in their peri-A than NFA patients. Decreased pAMPK and increased PDK4 and pIRS1 were observed in the peri-A of PHEO patients. PHEO patients also had significantly higher NOX4 protein expression and lower Nrf2 and HO-1 protein expression in their peri-A than NFA patients. In vitro, epinephrine treatment upregulated PDK4 expression, inhibited AMPK phosphorylation and enhanced IRS1 phosphorylation. The knockdown of PDK4 by siRNA upregulated pAMPK and downregulated pIRS1. In conclusion, PDK4 may play an essential role in hypercatecholamine-induced insulin resistance in the periadrenal adipose tissues of PHEO patients.

Aerobic exercise and lipolysis: A review of the β-adrenergic signaling pathways in adipose tissue

The objective of this study was to review the beta-adrenergic (β-AR) signaling pathways in adipose tissue, highlight key proteins involved in lypolisis and examine the effects of aerobic exercise on adipose tissue metabolism.

Effects of acute and chronic exercise on fat PI3K/AKT/GLUT4 signal pathway in type 2 diabetic rats

To study the effects of acute and chronic exercise on phosphatidylinositol 3-hydroxy kinase(PI3K)/protein kinase B(AKT)/glucose transporter 4(GLUT4)signaling pathway in adipose tissue of rats with type 2 diabetes mellitus (T2DM) induced by high-fat diet and low-dose streptozotocin (STZ). A total of 52 SD male rats aged 15 months were randomly divided into normal control group (13) and high-fat group (39), and fed normal and high fat diets. After 8 weeks, the body weight of the high-fat group was higher 20% than that of the normal control group. After a small dose of STZ, the blood glucose level was ＞16.7 mmol/l, and the model was successfully established. The diabetic model group was randomly divided into a diabetic control group (DC, n=13), a diabetic chronic exercise group (DCE, n=13), and a diabetic acute exercise group (DAE, n=13). The DCE group underwent an 8-week swimming exercise and the DAE group performed a one-time swimming exercise. Blood lipids, blood glucose and serum insulin levels were measured, and the contents of fat PI3K, AKT and GLUT4 proteins were determined by Western blot method. The levels of body weight, blood lipids, blood glucose and insulin in the diabetic group were significantly higher than those in the normal control group (P＜0.01); high density liptein cholesterol(HDL-C) levels were decreased (P＜0.05), and the expressions of PI3K, AKT and GLUT4 protein in adipose tissue were decreased (P＜0.01). After 8 weeks of swimming training, the levels of body weight, blood lipids, blood glucose and insulin all were decreased significantly (P＜0.01); while the level of HDL-C was increased (P＜0.05), and the expressions of PI3K, AKT and GLUT4 protein were increased (P＜0.01). After acute exercise, the levels of blood lipids, blood glucose and insulin were decreased (P＜0.05); the level of HDL-C was increased (P＜0.05), and the expression levels of fat PI3K, AKT and GLUT4 were increased significantly (P＜0.05). ①High fat diet combined with low-dose STZ induced damage to the PI3K/AKT pathway in adipose tissue of T2DM rats reduced insulin sensitivity. ②Acute and chronic aerobic exercise can improve the disorder of glucose and lipid metabolism through PI3K/AKT pathway, and the chronic exercise is better than acute exercise.

AKT and AMPK signaling pathways in adipose tissue from patients with metabolic unhealthy obesity

AKT and AMPK signaling pathways in adipose tissue from patients with metabolic unhealthy obesity

Development of microparticles for controlled release of resveratrol to adipose tissue and the impact of drug loading on particle morphology and drug release.

Resveratrol is a small molecule produced by various plants with a remarkable range of beneficial functions in animals. One of these is stimulating signaling pathways in adipose tissue that protect against obesity. Unfortunately, resveratrol suffers from poor bioavailability that inhibits its accumulation in target tissues, including fat, thus hindering the realization of its therapeutic potential. To address this, we are developing biodegradable microparticles as drug depots for controlled release of resveratrol within fat. In this study, resveratrol was encapsulated into poly(lactide-co-glycolide) microparticles using an oil-in-water emulsion/solvent evaporation technique. The oil phase consisted of resveratrol and poly(lactide-co-glycolide) dissolved in a mixture of dichloromethane and ethanol; meanwhile, the aqueous phase contained poly(vinyl alcohol) as the emulsifier. Increasing ethanol's volume ratio increased resveratrol's solubility in the oil phase and particle drug loading. The maximal loading achieved was 65 µg/mg (6.5%) and occurred when the ethanol to dichloromethane ratio was 1:3. Under these conditions, particles exhibited ruffled surfaces, which resulted in variable drug release over the first three days of a six-week release assay. By decreasing resveratrol and ethanol in the oil phase and increasing poly(vinyl alcohol) in the aqueous phase, smooth particles were achieved, but they suffered a 15-25-fold decrease in drug loading depending on size. Small particles exhibited higher drug loading and burst drug release compared to larger particles because of their higher specific surface area. Utilizing mild chemistry, we functionalized poly(vinyl alcohol) with fluorescein isothiocyanate and demonstrated that encapsulation of resveratrol in the particle decreases the amount of fluorescent polymer on the particle surface, suggesting resveratrol displaces the emulsifier during particle formation. Taken together, resveratrol can be encapsulated into poly(lactide-co-glycolide) microparticles, but it accumulates at the particle surface impacting drug loading, surface roughness, and drug release.

Methionine supply during the periparturient period enhances insulin signaling, amino acid transporters, and mechanistic target of rapamycin pathway proteins in adipose tissue of Holstein cows

Enhanced postruminal supply of Met during the periparturient period increases dry matter intake and milk yield. In nonruminants, adipose tissue is responsive to AA supply, and can use AA as fuels or for protein synthesis regulated in part via insulin and mechanistic target of rapamycin (mTOR) signaling. Whether enhancing supply of Met has an effect on insulin and mTOR pathways in adipose tissue in peripartal cows is unknown. Multiparous Holstein cows were assigned from -28 to 60 d relative to parturition to a basal diet (control; 1.47 Mcal/kg of dry matter and 15.3% crude protein prepartum; 1.67 Mcal/kg and 17.7% crude protein postpartum) or the control plus ethyl-cellulose rumen-protected Met (RPM). The RPM was fed individually at a rate of 0.09% of dry matter intake prepartum and 0.10% postpartum. Subcutaneous adipose tissue harvested at -10, 10, and 30 d relative to parturition (days in milk) was used for quantitative PCR and Western blotting. A glucose tolerance test was performed at -12 and 12 d in milk to evaluate insulin sensitivity. Area under the curve for glucose in the pre- and postpartum tended to be smaller in cows fed Met. Enhanced Met supply led to greater overall mRNA abundance of Gln (SLC38A1), Glu (SLC1A1), l-type AA (Met, Leu, Val, Phe; SLC3A2), small zwitterionic α-AA (SLC36A1), and neutral AA (SLC1A5) transporters. Abundance of AKT1, RPS6KB1, and EIF4EBP1 was also upregulated in response to Met. A diet × day interaction was observed for protein abundance of insulin receptor due to Met cows having lower values at 30 d postpartum compared with controls. The diet × day interaction was significant for hormone-sensitive lipase due to Met cows having greater abundance at 10 d postpartum compared with controls. Enhanced Met supply upregulated protein abundance of insulin-responsive proteins phosphorylated (p)-AKT, peroxisome proliferator-activated receptor gamma, and fatty acid synthase. Overall abundance of solute carrier family 2 member 4 tended to be greater in cows fed Met. A diet × day interaction was observed for mTOR protein abundance due to greater values for RPM cows at 30 d postpartum compared with controls. Enhanced RPM supply upregulated overall protein abundance of solute carrier family 1 member 3, p-mTOR, and ribosomal protein S6. Overall, data indicate that mTOR and insulin signaling pathways in adipose tissue adapt to the change in physiologic state during the periparturient period. Further studies should be done to clarify whether the activation of p-AKT or increased availability of AA leads to the activation of mTOR.

Reduced meal frequency alleviates high-fat diet-induced lipid accumulation and inflammation in adipose tissue of pigs under the circumstance of fixed feed allowance.

The present study was conducted to determine whether reduced meal frequency (MF) could restore high-fat diet (HFD)-modified phenotypes and microbiota under the condition of fixed feed allowance. A total of 32 barrows with initial weight of 61.6 ± 0.8kg were assigned to two diets [control diet (CON) versus HFD] and two meal frequencies [12 equal meals/day (M12) versus 2 equal meals/day (M2)], the trial lasted 8 weeks. The lipid metabolism and inflammatory response in adipose tissue as well as the profiles of intestinal microbiota and bacterial-derived metabolites were determined. M2 versus M12 feeding regimen decreased perirenal fat weight and serum triglyceride and liposaccharide (LPS) concentrations in HFD-fed pigs (P < 0.05). Reduced MF down-regulated mRNA expression of lipoprotein lipase, CD36 molecule, interleukin 1 beta, tumor necrosis factor alpha, toll-like receptor 4, myeloid differentiation factor 88 (MYD88), and nuclear factor kappa beta 1 as well as protein expression of MYD88 in perirenal fat of HFD-fed pigs (P < 0.05). M2 feeding regimen increased abundance of Prevotella and decreased abundance of Bacteroides in colonic content of HFD-fed pigs (P < 0.05). No difference in short-chain fatty acids (SCFAs) profile in colonic content was observed among four groups (P > 0.05). Our results suggested that M2 versus M12 feeding regimen ameliorated HFD-induced fat deposition and inflammatory response by decreasing fatty acid uptake and deactivating LPS/TLR4 signaling pathway in adipose tissue and restoring microbiota composition in distal intestine, without affecting SCFAs profile in distal luminal content.

FADS1 genotype is distinguished by human subcutaneous adipose tissue fatty acids, but not inflammatory gene expression

Single nucleotide polymorphisms (SNPs) in FADS1/FADS2 genes are associated with changes in serum and tissue polyunsaturated fatty acid (PUFA) content. PUFA regulate inflammatory signaling pathways in adipose tissue; however, the effect of SNPs in FADS1/FADS2 on adipose tissue inflammation is equivocal. The present study examined if SNPs in FADS1/FADS2 modify human subcutaneous adipose tissue (SAT) fatty acid profiles and the expression of genes associated with inflammation/immune function, lipid metabolism, and cellular differentiation. SAT fatty acids and the expression of 117 genes were measured in 174 men and women from the DiOGenes Study using gas chromatography and qRT-PCR, respectively. Associations between fatty acids, gene expression, and SNPs in FADS1/FADS2 were investigated by linear regression and multivariate analysis. Four SNPs (rs174537, rs174546, rs174556, rs174601) in FADS1/FADS2 were significantly associated with SAT fatty acids. All SNPs were in high linkage disequilibrium with the commonly reported rs174537 SNP in FADS1. Minor allele carriers for rs174537 (GT+TT) had reduced 20:4n-6 (p = 1.74E-5), lower delta-5 desaturase enzyme activity (p = 2.09E-9), and lower FADS1 gene expression (p = 0.03) compared to major GG carriers. Multivariate analysis revealed that 20:4n-6 and 20:3n-6 explained ~19% of the variance between rs174537 genotypes, while gene expression explained <7%. Receiver operating characteristic (ROC) curves indicated that rs174537 genotype can be distinguished with SAT fatty acids (AUC = 0.842), but not gene expression (AUC = 0.627). No differences in SAT inflammatory gene expression were observed between rs174537 genotypes. SAT 20:3n-6 levels were positively correlated with the expression of several inflammatory genes, and inversely correlated with FADS1 expression. This study showed that FADS1 genotype is distinguished by SAT fatty acid profiles, but not inflammatory gene expression.

Isocaloric Diets High in Animal or Plant Protein Reduce Liver Fat and Inflammation in Individuals With Type 2 Diabetes

Nonalcoholic fatty liver disease (NAFLD) is associated with increased risk of hepatic, cardiovascular, and metabolic diseases. High-protein diets, rich in methionine and branched chain amino acids (BCAAs), apparently reduce liver fat, but can induce insulin resistance. We investigated the effects of diets high in animal protein (AP) vs plant protein (PP), which differ in levels of methionine and BCAAs, in patients with type 2 diabetes and NAFLD. We examined levels of liver fat, lipogenic indices, markers of inflammation, serum levels of fibroblast growth factor 21 (FGF21), and activation of signaling pathways in adipose tissue. We performed a prospective study of individuals with type 2 diabetes and NAFLD at a tertiary medical center in Germany from June 2013 through March 2015. We analyzed data from 37 subjects placed on a diet high in AP (rich in meat and dairy foods; n= 18) or PP (mainly legume protein; n= 19) without calorie restriction for 6 weeks. The diets were isocaloric with the same macronutrient composition (30% protein, 40% carbohydrates, and 30% fat). Participants were examined at the start of the study and after the 6-week diet period for body mass index, body composition, hip circumference, resting energy expenditure, and respiratory quotient. Body fat and intrahepatic fat were detected by magnetic resonance imaging and spectroscopy, respectively. Levels of glucose, insulin, liver enzymes, and inflammation markers, as well as individual free fatty acids and free amino acids, were measured in collected blood samples. Hyperinsulinemic euglycemic clamps were performed to determine whole-body insulin sensitivity. Subcutaneous adipose tissue samples were collected and analyzed for gene expression patterns and phosphorylation of signaling proteins. Postprandial levels of BCAAs and methionine were significantly higher in subjects on the AP vs the PP diet. The AP and PP diets each reduced liver fat by 36%-48% within 6 weeks (for AP diet P= .0002; for PP diet P= .001). These reductions were unrelated to change in body weight, but correlated with down-regulation of lipolysis and lipogenic indices. Serum level of FGF21 decreased by 50% in each group (for AP diet P < .0002; for PP diet P < .0002); decrease in FGF21 correlated with loss of hepatic fat. In gene expression analyses of adipose tissue, expression of the FGF21 receptor cofactor β-klotho was associated with reduced expression of genes encoding lipolytic and lipogenic proteins. In patients on each diet, levels of hepatic enzymes and markers of inflammation decreased, insulin sensitivity increased, and serum level of keratin 18 decreased. In a prospective study of patients with type 2 diabetes, we found diets high in protein (either animal or plant) significantly reduced liver fat independently of body weight, and reduced markers of insulin resistance and hepatic necroinflammation. The diets appear to mediate these changes via lipolytic and lipogenic pathways in adipose tissue. Negative effects of BCAA or methionine were not detectable. FGF21 level appears to be a marker of metabolic improvement. ClinicalTrials.gov ID NCT02402985.