HFD-induced Weight Gain Research Articles

ODP010 Relaxin Receptor RXFP1 Knockout in Adipose Tissue Progenitor Cells Results in Resistance to High Fat Diet-Induced Weigh Gain

Abstract Relaxin is a polypeptide hormone that signals through its cognate receptor RXFP1. Previous work demonstrated that global RXFP1-knockout mice developed age-related adipose tissue fibrosis and dysfunction. Our preliminary data suggested that adipose tissue progenitor cells (APC) express RXFP1 in the white adipose tissue in mice. To determine the role of APC in relaxin signaling, we crossed floxed RXFP1 mice (RXFP1-fl/fl) with mice expressing tamoxifen-inducible CRE recombinase under control of the platelet-derived growth factor receptor-β (PDGFRβ) promoter to produce conditional RXFP1 knockout in adipose tissue progenitor cells and fibroblasts (RXFP1-PKO). After tamoxifen treatment, both RXFP1-fl/fl and RXFP1-PKO mice were placed on a high fat diet (58% calories from fat) supplemented with sucrose and fructose in the drinking water, or chow diet for 16 weeks. At the end of the study, body mass composition was measured using an Echo-MRI instrument. Adipose tissue fibrosis was assessed histologically by Sirius red staining. In response to the HFD, the control (fl/fl) mice reached an average weight of 48.3 ± 0.6g, while the RXFP1-PKO mice were resistant to weight gain, reaching only 40.3 ±3g (p<. 05). The body mass composition changed in the RXFP1-fl/fl mice on HFD (34. 0% fat/55.2% lean) compared to chow (14.7% fat/68.9% lean). The RXFP1-PKO mice had a significantly lower gain in fat mass on HFD (29.7% fat/59.1% lean on HFD; 12.6% fat/71. 0% lean on chow) compared to the RXFP-fl/fl mice. Histological analysis of the inguinal white adipose tissue (iWAT) revealed that while RXFP1-fl/fl mice developed adipocyte hypertrophy in response to the HFD, the RXFP1-PKO mice had smaller adipocyte size. This was accompanied by increased pericellular and perivascular fibrosis in the iWAT as determined by Sirius red staining. To determine if differentiation of APC was altered by loss of RXFP1, the stromal-vascular fraction of iWAT was extracted by collagenase treatment, and the APC isolated using antibody-coated magnetic beads (Miltenyi Biotec). The purified cells were cultured to confluence, treated with or without tamoxifen to induce CRE expression, then treated with differentiation cocktail. The APC from the RXFP1-PKO mice had a marked impairment in the ability differentiate to mature adipocytes after treatment with tamoxifen compared to untreated cells. In summary, the loss of RXFP1 in PDGFRβ-expressing cells resulted in resistance to HFD-induced weight and adipose tissue mass gain. This was accompanied by increased fibrosis in the iWAT and decreased adipocyte size. The APC had decreased adipogenic potential after loss of RXFP1. Taken together, the findings support a role for RXFP1 in the differentiation of adipose tissue progenitor cells, and in adipose tissue expansion after exposure to an obesogenic diet. Presentation: No date and time listed

Chiliadenus iphionoides Reduces Body Weight and Improves Parameters Related to Hepatic Lipid and Glucose Metabolism in a High-Fat-Diet-Induced Mice Model of NAFLD.

Non-alcoholic fatty liver disease (NAFLD) has become an epidemic with increasing prevalence. Limited treatment options and poor adherence emphasize the urgent need for novel therapies for the treatment and/or prevention of NAFLD. Bioactive natural compounds found in medicinal plants are promising as novel therapeutic agents for NAFLD. Chiliadenus iphionoides, a medicinal plant with several health-promoting properties, is an encouraging candidate. The current study aimed to elucidate the metabolic effects of C. iphionoides consumption in a high-fat-diet (HFD)-induced model of NAFLD. Male C57BL/6J mice (n = 40, 7-8-week-old) were fed a HFD (60% fat) with/without 0.5 or 2.5 gr C. iphionoides for fifteen weeks. Diet supplementation with C. iphionoides significantly ameliorated HFD-induced weight gain. Likewise, liver and adipose tissue weights were profoundly lower in the C. iphionoides-fed groups. Reduced liver steatosis in those groups was corroborated by histology, plasma liver enzyme levels, and lipid profile, indicating improved liver function and lipid metabolism in addition to enhanced insulin sensitivity. The addition of C. iphionoides to an obesogeneic diet can beneficially alleviate metabolic alterations and may be a practicable strategy for the management of NAFLD.

Vitamin D and Swimming Exercise Prevent Obesity in Rats under a High-Fat Diet via Targeting FATP4 and TLR4 in the Liver and Adipose Tissue.

The prevalence of obesity has risen in the last decades, and it has caused massive health burdens on people's health, especially metabolic and cardiovascular issues. The risk of vitamin D insufficiency is increased by obesity, because adipose tissue alters both the requirements for and bioavailability of vitamin D. Exercise training is acknowledged as having a significant and long-term influence on body weight control; the favorable impact of exercise on obesity and obesity-related co-morbidities has been demonstrated via various mechanisms. The current work illustrated the effects of vitamin D supplementation and exercise on obesity induced by a high-fat diet (HFD) and hepatic steatosis in rats and explored how fatty acid transport protein-4 (FATP4) and Toll-like receptor-4 antibodies (TLR4) might be contributing factors to obesity and related hepatic steatosis. Thirty male albino rats were divided into five groups: group 1 was fed a normal-fat diet, group 2 was fed an HFD, group 3 was fed an HFD and given vitamin D supplementation, group 4 was fed an HFD and kept on exercise, and group 5 was fed an HFD, given vitamin D, and kept on exercise. The serum lipid profile adipokines, interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were analyzed, and the pathological changes in adipose and liver tissues were examined. In addition, the messenger-ribonucleic acid (mRNA) expression of FATP4 and immunohistochemical expression of TLR4 in adipose and liver tissues were evaluated. Vitamin D supplementation and exercise improved HFD-induced weight gain and attenuated hepatic steatosis, along with improving the serum lipid profile, degree of inflammation, and serum adipokine levels. The expression of FATP4 and TLR4 in both adipose tissue and the liver was downregulated; it was noteworthy that the group that received vitamin D and was kept on exercise showed also improvement in the histopathological picture of this group. According to the findings of this research, the protective effect of vitamin D and exercise against obesity and HFD-induced hepatic steatosis is associated with the downregulation of FATP4 and TLR4, as well as a reduction in inflammation.

Carotenoids in orange carrots mitigate non-alcoholic fatty liver disease progression.

BackgroundCarotenoids are abundant in colored fruits and vegetables. Non-alcoholic fatty liver disease (NAFLD) is a global burden and risk factor for end-stage hepatic diseases. This study aims to compare the anti-NAFLD efficacy between carotenoid-rich and carotenoid-deficient vegetables.Materials and methodsMale C57BL/6J mice were randomized to one of four experimental diets for 15 weeks (n = 12 animals/group): Low-fat diet (LFD, 10% calories from fat), high-fat diet (HFD, 60% calories from fat), HFD with 20% white carrot powders (HFD + WC), or with 20% orange carrot powders (HFD + OC).ResultsWe observed that carotenoids in the orange carrots reduced HFD-induced weight gain, better than white carrots. Histological and triglyceride (TG) analyses revealed significantly decreased HFD-induced hepatic lipid deposition and TG content in the HFD + WC group, which was further reduced in the HFD + OC group. Western blot analysis demonstrated inconsistent changes of fatty acid synthesis-related proteins but significantly improved ACOX-1 and CPT-II, indicating that orange carrot carotenoids had the potential to inhibit NAFLD by improving β-oxidation. Further investigation showed significantly higher mRNA and protein levels of PPARα and its transcription factor activity.ConclusionCarotenoid-rich foods may display more potent efficacy in mitigating NAFLD than those with low carotenoid levels.

The effect of Xuezhikang capsule on gene expression profile in brown adipose tissue of obese spontaneously hypertensive rats

Ethnopharmacological relevanceObesity is a critical threat to global health, and brown adipose tissue (BAT) is a potential target for the treatment of obesity and comorbidities. Xuezhikang Capsule (XZK), an extract of red yeast rice, has remarkable clinical efficacy and is widely used for the treatment of hyperlipidemia and coronary heart disease. However, its modulatory effect on BAT remains unknown. Aim of this studyThe aim of this study was to investigate the protective mechanism of XZK in the obese spontaneously hypertensive rat (SHR) model by evaluating the regulatory effect of XZK on the BAT gene profile through transcriptome sequencing. Materials and methodsThe SHRs were randomly divided into four groups: the standard chow diet (STD) group, the STD supplemented with 126 mg/kg of XZK group, the high-fat diet (HFD) group, and the HFD supplemented with 126 mg/kg of XZK group. All SHRs were fed for 18 weeks. The metabolic phenotypes, including body weight, fat mass, oral glucose tolerance test (OGTT), and serum glucose and lipid levels, was evaluated, and hematoxylin and eosin staining (H&E) staining was performed to evaluate the adipose tissue histopathological phenotype. Transcriptome sequencing was performed to determine the mechanism by which XZK improves the metabolic phenotype and the expression of key differential expression genes was verified by real-time quantitative polymerase chain reaction (qRT-PCR). ResultsXZK inhibited HFD-induced weight gain and adipose tissue remodeling in SHRs and prevented hypertrophy of epididymal adipocytes and maintained the brown fat phenotype. XZK intervention also improved glucose and lipid metabolism in SHRs, as suggested by a reduction in serum triglyceride (TG), low-density cholesterol (LDL-C), and fasting blood glucose (FBG) levels as well as increasing in serum high-density cholesterol (HDL-C) levels. Transcriptome sequencing analysis confirmed the regulatory effect of XZK on the gene expression profile of BAT, and the expression patterns of 45 genes were reversed by the XZK intervention. Additionally, the results of the transcriptome analysis of 10 genes that are important for brown fat function were in line with the results of qRT-PCR. ConclusionsXZK protected SHRs from HFD-induced obesity, inhibited fat accumulation and improved glucolipid metabolism. Additionally, the protective effect of XZK on the overall metabolism of obese SHRs might partly be related to its regulatory effect on the BAT gene expression profile. These findings might provide novel therapeutic strategies for obesity-related metabolic diseases in traditional Chinese medicine (TCM).

Aerobic Exercise Prevents Chronic Inflammation and Insulin Resistance in Skeletal Muscle of High-Fat Diet Mice.

Obesity is commonly accompanied by chronic tissue inflammation and leads to insulin resistance. Aerobic exercise is an essential treatment for insulin resistance and has anti-inflammatory effects. However, the molecular mechanisms of exercise on obesity-associated inflammation and insulin resistance remain largely unknown. Here, we evaluated the effects of aerobic exercise on inflammation and insulin resistance in skeletal muscles of high-fat diet (HFD) mice. Male C57BL/6J mice were fed a high-fat diet or a normal diet for 12 weeks, and then aerobic training was performed on a treadmill for 8 weeks. Body weight, fasting blood glucose, food intake levels, and glucose and insulin tolerance were evaluated. The levels of cytokines, skeletal muscle insulin resistance, and inflammation were also analyzed. Eight weeks of aerobic exercise attenuated HFD-induced weight gain and glucose intolerance, and improved insulin sensitivity. This was accompanied by enhanced insulin signaling. Exercise directly resulted in a significant reduction of lipid content, inflammation, and macrophage infiltration in skeletal muscles. Moreover, exercise alleviated HFD-mediated inflammation by suppressing the activation of the NF-κB pathway within skeletal muscles. These results revealed that aerobic exercise could lead to an anti-inflammatory phenotype with protection from skeletal muscle insulin resistance in HFD-induced mice.

Swertiamarin ameliorates diet-induced obesity by promoting adipose tissue browning and oxidative metabolism in preexisting obese mice.

Obesity is a risk factor for many metabolic diseases. Efficient therapeutic strategies are urgently needed. Swertiamarin (STM) prevents obesity and the associated insulin resistance and inflammation. However, the therapeutic effects of STM on preexisting obesity remain unclear. Therefore, in this study we aim to investigate the effects of STM on energy expenditure and fat browning in mice with preexisting obesity. C57BL/6J mice are fed with a high-fat diet (HFD) for 8 weeks to induce obesity and then gavaged (or not) with STM for 10 weeks. The whole-body energy metabolism of mice is examined by indirect calorimetry. The results show that after 10 weeks of treatment, STM markedly prevents HFD-induced weight gain, chronic inflammation, insulin resistance, and hepatic steatosis. STM promotes oxygen consumption and energy expenditure. The level of uncoupling protein 1 is enhanced in the brown and white adipose tissues of STM-treated mice. STM increases the phosphorylation of AMP-activated protein kinase and the expressions of genes involved in fat oxidation, reducing fat deposition in skeletal muscles. Meanwhile, STM does not affect the intestinal microbiotic composition. Overall, STM supplementation may serve as a potential therapy for obesity.

Sexual dimorphism modulates metabolic and cognitive alterations under HFD nutrition and chronic stress exposure in mice. Correlation between spatial memory impairment and BDNF mRNA expression in hippocampus and spleen

AimsThe accumulated evidence suggests that lifestyle - specifically dietary habits and stress exposure - plays a detrimental role in health. The purpose of the present study was to analyze the interplay of stress, diet, and sex in metabolic and cognitive alterations. Main methodsFor this purpose, one-month-old C57Bl/6J mice were fed with a standard diet or high-fat diet (HFD). After eight weeks, one subgroup of mice from each respective diet was exposed to 20 weeks of chronic mild stress (CMS), whilst the others were left undisturbed. Key findingsAfter 28 weeks of HFD feeding, mice from both sexes were overweight, with an increase in caloric intake and abdominal and subcutaneous fat pads. Stress exposure induced a decrease in body weight, related to a decrease in caloric efficiency in both males and females. Results indicate that males are more susceptible than the females in modulating metabolic and cognitive functions under HFD and CMS. Although both sexes demonstrated HFD-induced weight gain, fat accumulation, insulin resistance, high cholesterol, only males exposed to CMS but not females have (i) impaired glucose tolerance with higher glucose level; (ii) significant prolonged latency in Barnes test, suggesting cognitive impairment; (iii) increased IFN-gamma expression in hippocampus, suggesting greater neuroinflammatory response; (iv) poorer cognitive performance related to a decrease in hippocampal and spleen BDNF mRNA expression. SignificanceThe main finding in this study is the presence of a sexual dimorphism in modulating metabolic and cognitive functions under HFD and CMS, showing males are more susceptible than females. In addition, poorer cognitive performance was related to a decrease in hippocampal BDNF mRNA expression. Interestingly, these changes were observed in the spleen as well.

Preventive and Therapeutic Effects of Krill Oil on Obesity and Obesity-Induced Metabolic Syndromes in High-Fat Diet-Fed Mice.

Obesity increases the risks of metabolic syndromes including nonalcoholic fatty liver disease (NAFLD), diabetic dyslipidemia, and chronic kidney disease. Dietary krill oil (KO) has shown antioxidant and anti-inflammatory properties, thereby being a therapeutic potential for obesity-induced metabolic syndromes. Thus, the effects of KO on lipid metabolic alteration were examined in a high-fat diet (HFD)-fed mice model. The HFD model (n = 10 per group) received an oral gavage with distilled water as a control, metformin at 250 mg/kg, and KO at 400, 200, and 100 mg/kg for 12 weeks. The HFD-induced weight gain and fat deposition were significantly reduced in the KO treatments compared with the control. Blood levels were lower in parameters for NAFLD (e.g., alanine aminotransferase, and triglyceride), type 2 diabetes (e.g., glucose and insulin), and renal dysfunction (e.g., blood urea nitrogen and creatinine) by the KO treatments. The KO inhibited lipid synthesis through the modification of gene expressions in the liver and adipose tissues and adipokine-mediated pathways. Furthermore, KO showed hepatic antioxidant activities and glucose lowering effects. Histopathological analyses revealed that the KO ameliorated the hepatic steatosis, pancreatic endocrine/exocrine alteration, adipose tissue hypertrophy, and renal steatosis. These analyses suggest that KO may be promising for inhibiting obesity and metabolic syndromes.

Glucose-dependent insulinotropic polypeptide receptor antagonist treatment causes a reduction in weight gain in ovariectomised high fat diet-fed mice.

Background and purposeThe incretin hormone, gastric inhibitory peptide/glucose‐dependent insulinotropic polypeptide (GIP), secreted by the enteroendocrine K‐cells in the proximal intestine, may regulate lipid metabolism and adiposity, but its exact role in these processes is unclear.Experimental approachWe characterized in vitro and in vivo antagonistic properties of a novel GIP analogue, mGIPAnt‐1. We further assessed the in vivo pharmacokinetic profile of this antagonist, as well as its ability to affect high‐fat diet (HFD)‐induced body weight gain in ovariectomised mice during an 8‐week treatment period.Key resultsmGIPAnt‐1 showed competitive antagonistic properties to the GIP receptor in vitro as it inhibited GIP‐induced cAMP accumulation in COS‐7 cells. Furthermore, mGIPAnt‐1 was capable of inhibiting GIP‐induced glucoregulatory and insulinotropic effects in vivo and has a favourable pharmacokinetic profile with a half‐life of 7.2 h in C57Bl6 female mice. Finally, sub‐chronic treatment with mGIPAnt‐1 in ovariectomised HFD mice resulted in a reduction of body weight and fat mass.Conclusion and ImplicationsmGIPAnt‐1 successfully inhibited acute GIP‐induced effects in vitro and in vivo and sub‐chronically induces resistance to HFD‐induced weight gain in ovariectomised mice. Our results support the development of GIP antagonists for the therapy of obesity.

Minocycline Reduces Hypothalamic Microglia Activation and Improves Metabolic Dysfunction in High Fat Diet-Induced Obese Mice.

Obesity is associated with insulin resistance, glucose intolerance, inflammation, and altered neuronal activity in brain regions controlling metabolic functions including food intake, energy expenditure, and glucose homeostasis, such as the hypothalamus. In this study, we tested the hypothesis that inhibiting inflammation with minocycline could reduce adverse metabolic consequences associated with high-fat diet (HFD)-induced obesity in mice and sought to determine if metabolic improvements were associated with reduced hypothalamic microglia activity. Male C57Bl/6J mice were placed on 60% HFD for 12 weeks, with minocycline (40 mg/kg, p.o.) or normal tap water given during the last 6 weeks of diet. Age-matched mice maintained on control diet were used as an additional comparator group. Metabolic function was assessed during the last week of treatment. Ramified (resting) and non-ramified (active) microglia were quantified in the hypothalamus following immunohistochemical staining of ionized calcium-binding adaptor 1 (Iba-1) and further assessed by RNAseq. In HFD fed mice, minocycline attenuated body mass and adiposity without altering food intake suggesting enhanced energy expenditure. Minocycline also attenuated hyperinsulinemia and improved insulin sensitivity in HFD mice. Increased microglial activation and autophagy gene network changes were observed in the paraventricular nucleus (PVN) of the hypothalamus of HFD mice, which was prevented by minocycline treatment. Contrary to PVN findings, there were no significant effects of either HFD or minocycline on microglia activation in the hypothalamic arcuate nucleus or central amygdala. Together, these findings suggest that minocycline improves HFD-induced weight gain and insulin resistance in part by reducing inflammatory processes in the PVN, a key hypothalamic region regulating metabolic function.

Young transgenic hMTH1 mice are protected against dietary fat-induced metabolic stress-implications for enhanced longevity.

hMTH1 protects against mutation during oxidative stress. It degrades 8‐oxodGTP to exclude potentially mutagenic oxidized guanine from DNA. hMTH1 expression is linked to ageing. Its downregulation in cultured cells accelerates RAS‐induced senescence, and its overexpression in hMTH1‐Tg mice extends lifespan. In this study, we analysed the effects of a brief (5 weeks) high‐fat diet challenge (HFD) in young (2 months old) and adult (7 months old) wild‐type (WT) and hMTH1‐Tg mice. We report that at 2 months, hMTH1 overexpression ameliorated HFD‐induced weight gain, changes in liver metabolism related to mitochondrial dysfunction and oxidative stress. It prevented DNA damage as quantified by a comet assay. At 7 months old, these HFD‐induced effects were less severe and hMTH1‐Tg and WT mice responded similarly. hMTH1 overexpression conferred lifelong protection against micronucleus induction, however. Since the canonical activity of hMTH1 is mutation prevention, we conclude that hMTH1 protects young mice against HFD by reducing genome instability during the early period of rapid growth and maximal gene expression. hMTH1 protection is redundant in the largely non‐growing, differentiated tissues of adult mice. In hMTH1‐Tg mice, expression of a less heavily mutated genome throughout life provides a plausible explanation for their extended longevity.

Effects of Drosophila melanogaster regular exercise and apolipoprotein B knockdown on abnormal heart rhythm induced by a high-fat diet.

Abnormal heart rhythm is a common cardiac dysfunction in obese patients, and its pathogenesis is related to systemic lipid accumulation. The cardiomyocyte-derived apoLpp (homologous gene in Drosophila of the human apolipoprotein B) plays an important role in whole-body lipid metabolism of Drosophila under a high-fat diet (HFD). Knockdown of apoLpp derived from cardiomyocytes can reduce HFD-induced weight gain and abdominal lipid accumulation. In addition, exercise can reduce the total amount of apoLpp in circulation. However, the relationship between regular exercise, cardiomyocyte-derived apoLpp and abnormal heart rhythm is unclear. We found that an HFD increased the level of triglyceride (TG) in the whole-body, lipid accumulation and obesity in Drosophila. Moreover, the expression of apoLpp in the heart increased sharply, the heart rate and arrhythmia index increased and fibrillation occurred. Conversely, regular exercise or cardiomyocyte-derived apoLpp knockdown reduced the TG level in the whole-body of Drosophila. This significantly reduced the arrhythmia induced by obesity, including the reduction of heart rate, arrhythmia index, and fibrillation. Under HFD conditions, flies with apoLpp knockdown in the heart could resist the abnormal cardiac rhythm caused by obesity after receiving regular exercise. HFD-induced obesity and abnormal cardiac rhythm may be related to the acute increase of cardiomyocyte-derived apoLpp. Regular exercise and inhibition of cardiomyocyte-derived apoLpp can reduce the HFD-induced abnormal cardiac rhythm.

Qing-Xin-Jie-Yu Granule alleviates atherosclerosis by reshaping gut microbiota and metabolic homeostasis of ApoE-/- mice

BackgroundAtherosclerosis (AS) is a key pathological factor in cardiovascular disease (CVD) and is characterized by high mortality and morbidity worldwide. Metabolic disorders, including pathoglycemia and dyslipidemia that lead to chronic inflammation, represent the prominent pathological characteristics of atherosclerotic CVD, Qing-Xin-Jie-Yu Granule (QXJYG) is a Chinese traditional decoction that has been clinically proven to be effective for patients with CVD. However, the underlying mechanisms have not been completely elucidated. PurposeTo investigate the protective effects of QXJYG against AS and its potential mechanisms. MethodsQXJYG was orally administered at doses of 1.664 and 4.992 g·kg-1·d-1 in a high-fat diet (HFD)-induced AS model using ApoE-/- mice. Histopathological and immunohistochemical analyses, ELISA, untargeted and targeted metabolomics analysis, 16S rRNA analysis, and RT-qPCR were performed to identify the therapeutic effects and mechanisms of QXJYG in treating HFD-induced AS. ResultsQXJYG retarded HFD-induced weight gain and reduced the increased serum levels of total cholesterol, triglycerides, and low-density lipoprotein-cholesterol, whereas high-dose QXJYG increased the serum level of high-density lipoprotein-cholesterol in HFD-fed ApoE-/- mice. Meanwhile, QXJYG reduced the serum levels, as well as aortas mRNA levels of the inflammatory cytokines, IL-1β and IL-6, which indicates that QXJYG is effective against metaflammation. Mechanistically, QXJYG reshaped the gut microbiota and its associated bile acids (BAs) metabolomic phenotype, partly by increasing the levels of BA synthesis enzymes, hepatic CYP7A1, and CYP27A1, while decreasing ileal FGF15 and β-Klotho mRNA expression, favoring facilitated de novo BAs synthesis and thereby driving cholesterol catabolic excretion. ConclusionOur findings indicate that QXJYG is effective against HFD-triggered chronic inflammation, and contributes to the alleviation of AS development, and the antiatherogenic properties of QXJYG may be partly due to the remodeling of the gut microbiota and BA metabolism. Although the results are encouraging, further clinical studies of anti-AS herbal medicines are required to elucidate the full potential of the gut microbiota and BA metabolism.

Transcription factor CREB3 is a potent regulator of high-fat diet-induced obesity and energy metabolism.

The endoplasmic reticulum senses alterations to cellular homeostasis that activates the unfolded protein response (UPR). UPR proteins are known to aid in regulating glucose and lipid metabolism. CREB3 is a UPR-associated transcription factor whose potential role in regulating energy metabolism remains unclear. Eight-week-old wild-type (WT) and Creb3+/- mice were placed on control and high-fat diets (HFD) for 8 weeks, and metabolic phenotypes characterized by weekly weighing, indirect calorimetry, body composition scans, glucose tolerance tests, plasma analysis, tissue lipid quantifications and gene/protein expression analysis. HFD weight gain in Creb3+/- males was reduced by 34% (p < 0.0001) and females by 39.5% (p = 0.014) from their WT counterparts. No differences were found in HFD food intake or total fecal lipids between genotypes. Creb3+/- mice had increased energy expenditure and respiratory exchange ratios (p = 0.002) relative to WT. Creb3+/- mice had significant reductions in absolute fat and lean tissue, while Creb3+/- females had significant reductions in body fat% and increased lean% composition (p < 0.0001) compared to WT females. Creb3+/- mice were protected from HFD-induced basal hyperglycemia (males p < 0.0001; females p = 0.0181). Creb3+/- males resisted HFD-induced hepatic lipid accumulation (p = 0.025) and glucose intolerance compared to WT (p < 0.0001) while Creb3+/- females were protected from lipid accumulation in skeletal muscle (p = 0.001). Despite the metabolic differences of Creb3+/- mice on HFD, lipid plasma profiles did not significantly differ from WT. Fasted Creb3+/- mice additionally revealed upregulation of hepatic energy expenditure and gluconeogenic genes such as Pgc-1a and Gr (glucocorticoid receptor) (p < 0.05), respectively. Reduced expression of CREB3 increased energy expenditure and the respiratory exchange ratio, and protected mice from HFD-induced weight gain, basal hyperglycemia, and sex-specific tissue lipid accumulation. We postulate that CREB3 is a novel key regulator of diet-induced obesity and energy metabolism that warrants further investigation as a potential therapeutic target in metabolic disorders.

Chloroquine modulates the sulforaphane anti-obesity mechanisms in a high-fat diet model: Role of JAK-2/ STAT-3/ SOCS-3 pathway

The phytochemical sulforaphane (SFN) has been studied for its potential anti-obesity effect, but neither its molecular targets nor its interaction with the antimalarial drug chloroquine (CQ) has been fully delineated. Therefore, high-fat diet (HFD) obese rats were randomly allocated into one of five groups and were left untreated or gavaged orally with SFN (0.5 or 1 mg/kg), CQ (5 mg/kg), or their combination (0.5/5 mg/kg) for six successive weeks to assess their potential interaction and the enrolled mechanisms. SFN effectively reduced the HFD-induced weight gain, blood glucose, and serum leptin levels, and improved lipid profile. On the molecular level, SFN inhibited the lipogenesis-related enzymes, namely sterol regulatory element-binding protein (SREBP)-1c, fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) in both liver and visceral white adipose tissue (vWAT) of HFD obese rats. SFN also turned off the inflammatory pathway conserved Janus kinase/signaling transducers and activators of transcription/suppressor of cytokine signaling (JAK-2/STAT-3/SOCS-3) in these tissues, as well as the inflammatory markers nuclear factor-kappa (NF-κ) B and interleukin (IL)-22 in serum. In contrast, SFN downregulated the gene expression of microRNA (miR-200a), while significantly increasing the autophagic parameters; viz., beclin-1, autophagy-related protein (ATG)-7, and microtubule-associated protein 2 light chain 3 (LC3-II) in both liver and vWAT. On most of the parameters mentioned above, treatment with CQ solely produced a satisfactory effect and intensified the low dose of SFN in the combination regimen. These findings demonstrated the beneficial effects of using CQ as an add-on anti-obesity medicine to SFN.

TRPC5 deletion in the central amygdala antagonizes high-fat diet-induced obesity by increasing sympathetic innervation.

Transient receptor potential channel 5 (TRPC5) is predominantly distributed in the brain, especially in the central amygdala (CeA), which is closely associated with pain and addiction. Although mounting evidence indicates that the CeA is related to energy homeostasis, the possible regulatory effect of TRPC5 in the CeA on metabolism remains unclear. Here, we reported that the expression of TRPC5 in the CeA of mice was increased under a high-fat diet (HFD). Specifically, the deleted TRPC5 protein in the CeA of mice using adeno-associated virus resisted HFD-induced weight gain, accompanied by increased food intake. Furthermore, the energy expenditure of CeA-specific TRPC5 deletion mice (TRPC5 KO) was elevated due to augmented white adipose tissue (WAT) browning and brown adipose tissue (BAT) activity. Mechanistically, deficiency of TRPC5 in the CeA boosted nonshivering thermogenesis under cold stimulation by stimulating sympathetic nerves, as the β3-adrenoceptor (Adrb3) antagonist SR59230A blocked the effect of TRPC5 KO on this process. In summary, TRPC5 deletion in the CeA alleviated the metabolic deterioration of mice fed a HFD, and these phenotypic improvements were correlated with the increased sympathetic distribution and activity of adipose tissue.

Acidic Activated Charcoal Prevents Obesity and Insulin Resistance in High-Fat Diet-Fed Mice.

Obesity is becoming a major public health problem worldwide. Making charcoal from wood (“Sumi-yaki”) has been a traditional activity in the southern part of Nagano Prefecture for centuries, with activated charcoal having reported detoxifying effects. However, it is unclear whether activated charcoal also possesses anti-obesity properties. Additionally, since activated charcoal is usually alkaline and might be affected by gastric juice, we evaluated the effect of acidic activated charcoal on high-fat diet (HFD)-induced obesity. This study demonstrated that co-treatment of acidic activated charcoal with a HFD significantly improved obesity and insulin resistance in mice in a dose-dependent manner. Metabolomic analysis of cecal contents revealed that neutral lipids, cholesterol, and bile acids were excreted at markedly higher levels in feces with charcoal treatment. Moreover, the hepatic expressions of genes encoding cholesterol 7 alpha-hydroxylase and hydroxymethylglutaryl-CoA reductase/synthase 1 were up-regulated by activated charcoal, likely reflecting the enhanced excretions from the intestine and the enterohepatic circulation of cholesterol and bile acids. No damage or abnormalities were detected in the gastrointestinal tract, liver, pancreas, and lung. In conclusion, acidic activated charcoal may be able to attenuate HFD-induced weight gain and insulin resistance without serious adverse effects. These findings indicate a novel function of charcoal to prevent obesity, metabolic syndrome, and related diseases.

Ramulus Mori (Sangzhi) Alkaloids Alleviate High-Fat Diet-Induced Obesity and Nonalcoholic Fatty Liver Disease in Mice.

Nonalcoholic fatty liver disease (NAFLD), obesity, and type 2 diabetes mellitus (T2DM) have highly related mechanisms. Ramulus Mori (Sangzhi) alkaloids (SZ-A) from Morus alba L. were approved in 2020 for the treatment of T2DM. In this study, we examined the therapeutic effects and mechanism of SZ-A on obesity and NAFLD in mice. Mice (C57BL/6J) fed a high-fat diet (HFD) for 14 weeks were treated with SZ-A for another 6 weeks. HFD-induced weight gain was reduced by SZ-A in a dose-dependent manner. SZ-A treatment significantly stimulated adiponectin expression and secretion in adipose tissue and 3T3-L1 adipocytes. Additionally, SZ-A markedly reduced hepatic steatosis (triglyceride, total cholesterol) and expression of pro-inflammatory and pro-fibrotic genes. SZ-A regulated lipid metabolism and oxidative stress (malondialdehyde (MDA), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione (GSH)) in the liver. Palmitic acid-induced insulin resistance and lipid accumulation in HepG2 cells were also repressed by SZ-A. Collectively, SZ-A protected mice from HFD-induced NAFLD through an indirect effect of improved systemic metabolism reducing bodyweight, and a direct effect by enhancing the lipid metabolism of HepG2 cells. The weight-loss effect of SZ-A in mice was partly due to improved fatty oxidation instead of influencing food consumption.

The Ameliorating Effects of Apple Polyphenol Extract on High-Fat-Diet-Induced Hepatic Steatosis Are SIRT1-Dependent: Evidence from Hepatic-Specific SIRT1 Heterozygous Mutant C57BL/6 Mice

Apple polyphenol extract (APE) has been reported to possess protective effects against hepatic steatosis. To explore whether APE-induced alleviation of hepatic steatosis is SIRT1-dependent, the present study was carried out using wild-type and hepatic SIRT1 heterozygous mutant (Sirt1+/-) C57BL/6 mice. On consideration of the sex disparity related to hepatic steatosis morbidity, both male and female mice were included in the study. Six to eight week old mice were fed a high-fat diet (HFD) and randomly assigned to one of the following groups: (1) wild-type mice (wt+HFD), (2) Sirt1+/- mice (Sirt1+/-+HFD), and (3) Sirt1+/- mice with 500 mg/(kg·bw·d) APE intragastric administration (Sirt1+/-+HAP). HFD-induced weight gain and triglyceride accumulation was more prominent in Sirt1+/- mice in comparison to wild-type mice. Following APE treatment, these effects were significantly reduced along with the alleviation of hepatic steatosis via upregulated expression of SIRT1 at the protein and mRNA levels in both male and female mice. However, APE differentially regulated the genes related to lipid metabolism (Lkb1, Ampk, Hsl, Srebp-1c, Abcg1, and Cd36) in a sex-specific manner. Moreover, APE treatment altered gut microbiota composition, with an increased relative abundance of Akkermansia and a decreased Firmicutes/Bacterodetes ratio. Thus, our study provided new evidence supporting our hypothesis that APE-induced alleviation of hepatic steatosis is SIRT1-dependent.