Obesity-induced Metabolic Diseases Research Articles

TNFα-induced NLRP3 inflammasome mediates adipocyte dysfunction and activates macrophages through adipocyte-derived lipocalin 2

Background and aimsObesity is a state of chronic low-grade systemic inflammation. Recent studies showed that NLRP3 inflammasome initiates metabolic dysregulation in adipose tissues, primarily through activation of adipose tissue infiltrated macrophages. However, the mechanism of NLRP3 activation and its role in adipocytes remains elusive. Therefore, we aimed to examine the activation of TNFα-induced NLRP3 inflammasome in adipocytes and its role on adipocyte metabolism and crosstalk with macrophages. MethodsThe effect of TNFα on adipocyte NLRP3 inflammasome activation was measured. Caspase-1 inhibitor (Ac-YVAD-cmk) and primary adipocytes from NLRP3 and caspase-1 knockout mice were utilized to block NLRP3 inflammasome activation. Biomarkers were measured by using real-time PCR, western blotting, immunofluorescence staining, and enzyme assay kits. Conditioned media from TNFα-stimulated adipocytes was used to establish the adipocyte-macrophage crosstalk. Chromatin immunoprecipitation assay was used to identify the role of NLRP3 as a transcription factor. Mouse and human adipose tissues were collected for correlation analysis. ResultsTNFα treatment induced NLRP3 expression and caspase-1 activity in adipocytes, partly through autophagy dysregulation. The activated adipocyte NLRP3 inflammasome participated in mitochondrial dysfunction and insulin resistance, as evidenced by the amelioration of these effects in Ac-YVAD-cmk treated 3T3-L1 cells or primary adipocytes isolated from NLRP3 and caspase-1 knockout mice. Particularly, the adipocyte NLRP3 inflammasome was involved in glucose uptake regulation. Also, TNFα induced expression and secretion of lipocalin 2 (Lcn2) in a NLRP3-dependent manner. NLRP3 could bind to the promoter and transcriptionally regulate Lcn2 in adipocytes. Treatment with adipocyte conditioned media revealed that adipocyte-derived Lcn2 was responsible for macrophage NLRP3 inflammasome activation, working as a second signal. Adipocytes isolated from high-fat diet mice and adipose tissue from obese individuals showed a positive correlation between NLRP3 and Lcn2 gene expression. ConclusionsThis study highlights the importance of adipocyte NLRP3 inflammasome activation and novel role of TNFα-NLRP3-Lcn2 axis in adipose tissue. It adds rational for the current development of NLRP3 inhibitors for treating obesity-induced metabolic diseases.

Deletion or inhibition of PTPRO prevents ectopic fat accumulation and induces healthy obesity with markedly reduced systemic inflammation

AimsChronic inflammation plays crucial roles in obesity-induced metabolic diseases. Protein tyrosine phosphatase receptor type O (PTPRO) is a member of the R3 subfamily of receptor-like protein tyrosine phosphatases. We previously suggested a role for PTPRO in the inactivation of the insulin receptor. The present study aimed to elucidate the involvement of PTPRO in the control of glucose and lipid metabolism as well as in obesity-induced systemic inflammation. Materials and methodsLipid accumulation in adipose tissue and the liver, the expression of inflammatory cytokines, and insulin resistance associated with systemic inflammation were investigated in hyper-obese Ptpro-KO mice by feeding a high-fat/high-sucrose diet (HFHSD). The effects of the administration of AKB9778, a specific inhibitor of PTPRO, to ob/ob mice and cultured 3T3-L1 preadipocyte cells were also examined. Key findingsPtpro was highly expressed in visceral white adipose tissue and macrophages. Ptpro-KO mice fed HFHSD were hyper-obese, but did not have ectopic fat accumulation in the liver, dysfunctional lipid and glucose homeostasis, systemic inflammation, or insulin resistance. The administration of AKB9778 reproduced “the healthy obese phenotypes” of Ptpro-KO mice in highly obese ob/ob mice. Furthermore, the inhibition of PTPRO promoted the growth of lipid droplets in adipocytes through an increase in the phosphorylation of Tyr(117) in vimentin. SignificanceHealthy systemic conditions with the attenuation of inflammation in hyper-obese Ptpro-KO mice were associated with the expansion of adipose tissue and low activation of NF-κb. Therefore, PTPRO may be a promising target to ameliorate hepatic steatosis and metabolic dysfunction.

Effect of Structured Phenolic Lipids with EPA/DHA and Gallic Acid against Metabolic-Associated Fatty Liver Disease (MAFLD) in Mice.

Obesity is the leading risk factor for developing metabolic (dysfunction)-associated fatty liver disease (MAFLD). The food industry has an essential role in searching for new strategies to improve primary food sources to revert some of the metabolic alterations induced by obesity. There is consistent evidence that long-chain polyunsaturated fatty acids (n-3 LCPUFA) belonging to the n-3 series, i.e., eicosapentaenoic (20:5n-3, EPA) and docosahexaenoic (22:6n-3, DHA) acids, could revert some alterations associated with obesity-induced metabolic diseases. A relevant tool is the synthesis of structured acylglycerols (sAG), which include EPA or DHA at the sn-2 position. On the other hand, it has been reported that a crucial role of antioxidants is the reversion of MAFLD. In this work, we studied the effects of new molecules incorporating gallic acid (GA) into EPA/DHA-rich structured lipids. Mice were fed with a high-fat diet (60%) for three months and were then divided into five groups for supplementation with sAG and sAG structured with gallic acid (structured phenolic acylglycerols, sPAG). sPAG synthesis was optimized using a 2²-screening factorial design based on the response surface methodology (RSM). Our results show that treatment of sPAG was effective in decreasing visceral fat, fasting glycemia, fasting insulin, suggesting that this new molecule has a potential use in the reversal of MAFLD-associated alterations.

Resistin impairs mitochondrial homeostasis via cyclase-associated protein 1-mediated fission, leading to obesity-induced metabolic diseases

ObjectiveOne of the suggested mechanisms of obesity-induced insulin resistance is mitochondrial dysfunction in target tissues such as skeletal muscle. In our study, we examined whether resistin, an adipokine associated with obesity-mediated insulin resistance, induced metabolic disorders by impairing mitochondrial homeostasis. MethodsThe morphology and function of mitochondria of skeletal muscle were examined in resistin-knockout and humanized resistin mice that were subjected to high-fat diet for 3 months. Morphology was examined by transmission electron microscopy. Mitochondria bioenergetics of skeletal muscle were evaluated using a Seahorse XF96 analyzer. Human skeletal myoblasts were used for in vitro studies on signaling mechanisms in responses to resistin. ResultsA high-fat diet in humanized resistin mice increased fragmented and shorter mitochondria in the skeletal muscle, whereas resistin-knockout mice had healthy normal mitochondria. In vitro studies showed that human resistin treatment impaired mitochondrial homeostasis by inducing mitochondrial fission, leading to a decrease in ATP production and mitochondrial dysfunction. Induction of mitochondrial fission by resistin was accompanied by increased formation of mitochondria-associated ER membranes (MAM). At the same time, resistin induced up-regulation of the protein kinase A (PKA) pathway. This activation of PKA induced phosphorylation of Drp1 at serine 616, leading to Drp1 activation and subsequent induction of mitochondrial fission. The key molecule that mediated human resistin-induced mitochondrial fission was adenylyl cyclase-associated protein 1 (CAP1), which was reported as a bona fide receptor for human resistin. Moreover, our newly developed biomimetic selective blocking peptide could repress human resistin-mediated mitochondrial dysfunction. High-fat diet-fed mice showed lower exercise capacity and higher insulin resistance, which was prevented by a novel peptide to block the binding of resistin to CAP1 or in the CAP1-knockdown mice. ConclusionsOur study demonstrated that human resistin induces mitochondrial dysfunction by inducing abnormal mitochondrial fission. This result suggests that the resistin-CAP1 complex could be a potential therapeutic target for the treatment of obesity-related metabolic diseases such as diabetes and cardiometabolic diseases.

Exercise training rescues adipose tissue spexin expression and secretion in diet-induced obese mice

Exercise training improves obesity-induced metabolic diseases through regulation of adipokines. Previous studies have shown that adipocyte-spexin participates in metabolic diseases such as obesity and diabetes via the modulation of energy homeostasis and insulin resistance. The objective of this research was to investigate the effects of swimming exercise on the levels of adipocyte-spexin and the underlying mechanisms. The normal chow diet (NC)-fed and high-fat diet (HFD)-fed mice were divided into exercise or sedentary groups. The expression and secretion of spexin in adipose tissue were assessed by quantitative real-time PCR and ELISA. The present findings uncovered the effect of exercise-induced spexin expression in the adipose tissue of obese mice. Besides, chronic exercise-induced upregulation of adipose spexin may be mediated by COUP-TF2 and KLF9. In addition, constant-moderate intensity exercise increased the levels of GLUT4, SIRT1 and PGC-1α in the skeletal muscles of mice. These results suggest that spexin is a potential mediator for exercise to ameliorate obesity-induced insulin resistance, namely, the beneficial effect of exercise on insulin sensitivity is at least partly mediated by spexin. Thus, exercise restores spexin production and release, which increases insulin sensitivity and maintains metabolic balance in the adipose tissues of HFD-induced obese mice.

Gasdermin D Deficiency Does Not Protect Mice from High-Fat Diet-Induced Glucose Intolerance and Adipose Tissue Inflammation.

The adipose tissue NLRP3 inflammasome has recently emerged as a contributor to obesity-related metabolic inflammation. Recent studies have demonstrated that the activation of the NLRP3 inflammasome cleaves gasdermin D (GSDMD) and induces pyroptosis, a proinflammatory programmed cell death. However, whether GSDMD is involved in the regulation of adipose tissue function and the development of obesity-induced metabolic disease remains unknown. The aim of the present study was to investigate the role of GSDMD in adipose tissue inflammation as well as whole-body metabolism using GSDMD-deficient mice fed a high-fat diet (HFD) for 30 weeks. The effects of GSDMD deficiency on adipose tissue, liver, and isolated macrophages from wild-type (WT) and GSDMD knockout (KO) mice were examined. In addition, 3T3-L1 cells were used to examine the expression of GSDMD during adipogenesis. The results demonstrate that although HFD-induced inflammation was partly ameliorated in isolated macrophages and liver, adipose tissue remained unaffected by GSDMD deficiency. Compared with the WT HFD mice, GSDMD KO HFD mice exhibited a mild increase in HFD-induced glucose intolerance with increased systemic and adipose tissue IL-1β levels. Interestingly, GSDMD deficiency caused accumulation of fat mass when challenged with HFD, partly by suppressing the expression of peroxisome proliferator-activated receptor gamma (PPARγ). The expression of GSDMD mRNA and protein was dramatically suppressed during adipocyte differentiation and was inversely correlated with PPARγ expression. Together, these findings indicate that GSDMD is not a prerequisite for HFD-induced adipose tissue inflammation and suggest a noncanonical function of GSDMD in regulation of fat mass through PPARγ.

Identification of key sex-specific pathways and genes in the subcutaneous adipose tissue from pigs using WGCNA method

BackgroundAdipose tissues (ATs), including visceral ATs (VATs) and subcutaneous ATs (SATs), are crucial for maintaining energy and metabolic homeostasis. SATs have been found to be closely related to obesity and obesity-induced metabolic disease. Some studies have shown a significant association between subcutaneous fat metabolism and sexes. However, the molecular mechanisms for this association are still unclear. Here, using the pig as a model, we investigated the systematic association between the subcutaneous fat metabolism and sexes, and identified some key sex-specific pathways and genes in the SATs from pigs.ResultsThe results revealed that 134 differentially expressed genes (DEGs) were identified in female and male pigs from the obese group. A total of 17 coexpression modules were detected, of which six modules were significantly correlated with the sexes (P < 0.01). Among the significant modules, the greenyellow module (cor = 0.68, P < 9e-06) and green module (cor = 0.49, P < 0.003) were most significantly positively correlated with the male and female, respectively. Functional analysis showed that one GO term and four KEGG pathways were significantly enriched in the greenyellow module while six GO terms and six KEGG pathways were significantly enriched in the green module. Furthermore, a total of five and two key sex-specific genes were identified in the two modules, respectively. Two key sex-specific pathways (Ras-MAPK signaling pathway and type I interferon response) play an important role in the SATs of males and females, respectively.ConclusionsThe present study identified some key sex-specific pathways and genes in the SATs from pigs, which provided some new insights into the molecular mechanism of being involved in fat formation and immunoregulation between pigs of different sexes. These findings may be beneficial to breeding in the pig industry and obesity treatment in medicine.

Integrated Transcriptomics and Network Pharmacology Analysis of the Mechanism of Quinoa Flavone in Repairing the Damage of Intestinal Endocrine Cells in Obesity-Induced Metabolic Diseases

Integrated Transcriptomics and Network Pharmacology Analysis of the Mechanism of Quinoa Flavone in Repairing the Damage of Intestinal Endocrine Cells in Obesity-Induced Metabolic Diseases

LRG1 is an adipokine that mediates obesity-induced hepatosteatosis and insulin resistance.

Dysregulation in adipokine biosynthesis and function contributes to obesity-induced metabolic diseases. However, the identities and functions of many of the obesity-induced secretory molecules remain unknown. Here, we report the identification of leucine-rich alpha-2-glycoprotein 1 (LRG1) as an obesity-associated adipokine that exacerbates high fat diet-induced hepatosteatosis and insulin resistance. Serum levels of LRG1 were markedly elevated in obese humans and mice compared with their respective controls. LRG1 deficiency in mice greatly alleviated diet-induced hepatosteatosis, obesity, and insulin resistance. Mechanistically, LRG1 bound with high selectivity to the liver and promoted hepatosteatosis by increasing de novo lipogenesis and suppressing fatty acid β-oxidation. LRG1 also inhibited hepatic insulin signaling by downregulating insulin receptor substrates 1 and 2. Our study identified LRG1 as a key molecule that mediates the crosstalk between adipocytes and hepatocytes in diet-induced hepatosteatosis and insulin resistance. Suppressing LRG1 expression and function may be a promising strategy for the treatment of obesity-related metabolic diseases.

White adipocyte-targeted dual gene silencing of FABP4/5 for anti-obesity, anti-inflammation and reversal of insulin resistance: Efficacy and comparison of administration routes

Obesity is a serious health problem with tremendous economic and social consequences, which is associated with metabolic diseases and cancer. Currently available anti-obesity drugs acting in the gastrointestinal tract, or the central nervous system have shown limited efficacy in the reduction of obesity, accompanied by severe side effects. Therefore, a novel therapeutic delivery targeting adipocytes and normalizing excess fat transport and accumulation is necessary to maximize efficacy and reduce side effects for long-term treatment. Fatty acid binding protein 4 (FABP4) is an adipokine that coordinates lipid transport in mature adipocyte and its inhibition in obesity model showed weight loss and normalized insulin response. Reduction of FABP4 level in adipocytes was compensated by fatty acid binding protein 5 (FABP5), which resulted in reduction of recovery of obesity and co-morbidities related to obesity by FABP4 knock-down alone. In this study, we developed a non-viral gene delivery system, sh (FABP4/5)/ATS9R, that silences FABP4 and FABP5 simultaneously with oligopeptide (ATS9R) that can selectively target mature adipocyte. For future clinical application to increase patient compliance, sh (FABP4/5)/ATS9R was administered subcutaneously and intraperitoneally to obese animal model and both routes demonstrated startling dual gene efficacy in visceral adipose tissues. Furthermore, dual gene silencing efficiently alleviated obesity, improved insulin sensitivity and restored hepatic metabolism in high fat diet-induced type 2 diabetes mouse model. Targeted-dual gene silencing of sh (FABP4/5)/ATS9R in adipose tissues demonstrated synergistic effects to overcome obesity and obesity-induced metabolic diseases and beneficial effects against liraglutide, providing a great potential for future translational research.

Danning tablets alleviate high fat diet-induced obesity and fatty liver in mice via modulating SREBP pathway

Ethnopharmacological relevanceThe traditional Chinese formula Danning tablets exhibit wide clinical applications in liver and gallbladder diseases, and currently it is reported to be effective on fatty liver disease in clinical trials. However, the underlying mechanisms remain elusive. Aim of the studyThe purpose of the present study was to assess the effects and potential pharmacological mechanisms of Danning tablet against high fat diet (HFD)-induced obesity, fatty liver, and related metabolic disorders in mice. Materials and methodsC57BL/6 J male mice were treated with HFD for 12 weeks to trigger obesity and fatty liver condition. Then those mice were randomly divided into 5 groups, namely HFD, Danning tablet (0.75, 1.5 or 3 g/kg bodyweight) or lovastatin (30 mg/kg bodyweight) for extra 6 weeks’ treatment of HFD. Food intake and bodyweight were recorded each week. In the last week, before the mice were sacrificed, fasting blood glucose levels and insulin levels were measured. Furthermore, insulin and glucose tolerance tests were performed. Blood and hepatic lipid levels were examined, the lipid metabolism-associated gene expressions and protein levels in the liver or adipose tissues were assayed after sacrificing all mice. ResultsOur results demonstrated that a high dose of Danning tablet (3 g/kg) treatment mitigated body weight gain, reduced blood and hepatic cholesterol and triglyceride levels. The morphology analysis showed that Danning tablets could reduce lipid accumulation in both liver and brown adipose tissue. Moreover, Danning tablets could improve fasting blood glucose levels and ameliorate glucose and insulin tolerance in HFD-induced obese mice. Furthermore, qRT-PCR analysis revealed that the mRNA expressions of SREBP-1 and SREBP-2 as well as their target genes were remarkedly down-regulated in the liver and adipose tissue of diet-induced obesity (DIO) mice after treating those mice with Danning tablets. ConclusionOur results indicated that Danning tablets could improve the obesity-induced metabolic associated fatty liver disease (MAFLD) and related metabolic disorders. The potential mechanism may probably involve the regulation of the SREBP pathway.

Macrophage and Adipocyte Mitochondrial Dysfunction in Obesity-Induced Metabolic Diseases.

Obesity is one of major health burdens of modern society as it contributes to the growing prevalence of its related comorbidities, such as diabetes, cardiovascular diseases, and some cancers. A series of innate immune cells, especially macrophages, and adipocytes have been implicated in the pathogenesis of obesity. Mitochondrial dysfunction, which is induced by obesity, are critical mediators in initiating inflammation in macrophages and adipocytes, and subsequent systemic insulin resistance. In this review, we discuss new findings on how obesity impairs mitochondrial function in macrophages and adipocytes and how this dysfunction contributes to obesity and its comorbidities. We also summarize drugs that treat metabolic diseases by targeting mitochondrial dysfunction.

Depletion of adipocyte sphingosine kinase 1 leads to cell hypertrophy, impaired lipolysis, and nonalcoholic fatty liver disease

Sphingolipids have become established participants in the pathogenesis of obesity and its associated maladies. Sphingosine kinase 1 (SPHK1), which generates S1P, has been shown to increase in liver and adipose of obese humans and mice and to regulate inflammation in hepatocytes and adipose tissue, insulin resistance, and systemic inflammation in mouse models of obesity. Previous studies by us and others have demonstrated that global sphingosine kinase 1 KO mice are protected from diet-induced obesity, insulin resistance, systemic inflammation, and NAFLD, suggesting that SPHK1 may mediate pathological outcomes of obesity. As adipose tissue dysfunction has gained recognition as a central instigator of obesity-induced metabolic disease, we hypothesized that SPHK1 intrinsic to adipocytes may contribute to HFD-induced metabolic pathology. To test this, we depleted Sphk1 from adipocytes in mice (SK1fatKO) and placed them on a HFD. In contrast to our initial hypothesis, SK1fatKO mice displayed greater weight gain on HFD and exacerbated impairment in glucose clearance. Pro-inflammatory cytokines and neutrophil content of adipose tissue were similar, as were levels of circulating leptin and adiponectin. However, SPHK1-null adipocytes were hypertrophied and had lower basal lipolytic activity. Interestingly, hepatocyte triacylglycerol accumulation and expression of pro-inflammatory cytokines and collagen 1a1 were exacerbated in SK1fatKO mice on a HFD, implicating a specific role for adipocyte SPHK1 in adipocyte function and inter-organ cross-talk that maintains overall metabolic homeostasis in obesity. Thus, SPHK1 serves a previously unidentified essential homeostatic role in adipocytes that protects from obesity-associated pathology. These findings may have implications for pharmacological targeting of the SPHK1/S1P signaling axis.

The Effects of Triterpenoid Saponins from the Seeds of Momordica cochinchinensis on Adipocyte Differentiation and Mature Adipocyte Inflammation.

Obesity is a medical condition in which abnormal or excessive fat accumulates to an extent that is associated with various diseases. In our ongoing research to figure out natural products with anti-obesity effects, a phytochemical investigation of the EtOH extract of the seeds of Momordica cochinchinensis was carried out, which resulted in the isolation of two major triterpenoid saponins: gypsogenin 3-O-β-d-galactopyranosyl(1→2)-[α-l-rhamnopyranosyl (1→3)]-β-d-glucuronopyranoside (1) and quillaic acid 3-O-β-d-galactopyranosyl(1→2)-[α-l-rhamnopyranosyl(1→3)]-β-d-glucuronopyranoside (2). Then, the effects of the isolated triterpenoid saponins (1 and 2) on adipocyte differentiation were evaluated, and it was demonstrated that the isolated saponin (1) showed inhibitory effects on adipogenesis. In mature adipocytes, the isolated saponin (1) reversed tumor necrosis factor α (TNFα)-induced proinflammatory cytokine gene expression. Additionally, the isolated saponin (1) reduced lipolytic gene expression leading to decreased basal lipolysis activity. Collectively, these findings suggest that saponin (1) of M. cochinchinensis exerts beneficial effects in the regulation of adipogenesis and adipocyte inflammation and could be a potential therapeutic alternative in the treatment of obesity-induced metabolic diseases.

Adipocyte Specific HO-1 Gene Therapy is Effective in Antioxidant Treatment of Insulin Resistance and Vascular Function in an Obese Mice Model.

Obesity is a risk factor for vascular dysfunction and insulin resistance. The study aim was to demonstrate that adipocyte-specific HO-1 (heme oxygenase-1) gene therapy is a therapeutic approach for preventing the development of obesity-induced metabolic disease in an obese-mice model. Specific expression of HO-1 in adipose tissue was achieved by using a lentiviral vector expressing HO-1 under the control of the adiponectin vector (Lnv-adipo-HO-1). Mice fed a high-fat diet (HFD) developed adipocyte hypertrophy, fibrosis, decreased mitochondrial respiration, increased levels of inflammatory adipokines, insulin resistance, vascular dysfunction, and impaired heart mitochondrial signaling. These detrimental effects were prevented by the selective expression of HO-1 in adipocytes. Lnv-adipo-HO-1-transfected mice on a HFD display increased cellular respiration, increased oxygen consumption, increased mitochondrial function, and decreased adipocyte size. Moreover, RNA arrays confirmed that targeting adipocytes with HO-1 overrides the genetic susceptibility of adiposopathy and correlated with restoration of the expression of anti-inflammatory, thermogenic, and mitochondrial genes. Our data demonstrate that HO-1 gene therapy improved adipose tissue function and had positive impact on distal organs, suggesting that specific targeting of HO-1 gene therapy is an attractive therapeutic approach for improving insulin sensitivity, metabolic activity, and vascular function in obesity.

Kupffer Cell Isolation from Human Biopsies.

Liver macrophages (LMs) are phagocytic cells that play an important role in many liver disorders due to their ability to respond to a variety of stimuli and activating signals.It is currently debated whether LMs activation from an anti-inflammatory to a proinflammatory phenotype contributes to obesity-induced metabolic diseases. We recently found that LMs can produce noninflammatory factors, such as the protein IGFBP7, able to directly regulate hepatic glucose production and lipid accumulation in the liver. However, while in a mouse model of obesity and insulin resistance LM-Igfbp7 expression is pathologically increased, in obese insulin-resistant patients LM-IGFBP7 is edited at RNA level independently of an effect on its expression. This discrepancy between results in animals and humans confirms the importance to perform molecular investigation directly on human's isolated cells. Here, we describe a protocol to isolate liver macrophages from human liver biopsy .

Safety and tolerability of experimental hookworm infection in humans with metabolic disease: study protocol for a phase 1b randomised controlled clinical trial

BackgroundAbdominal obesity and presence of the metabolic syndrome (MetS) significantly increase the risk of developing diseases such as Type 2 diabetes mellitus (T2DM) with escalating emergence of MetS and T2DM constituting a significant public health crisis worldwide. Lower prevalence of inflammatory and metabolic diseases such as T2DM in countries with higher incidences of helminth infections suggested a potential role for these parasites in the prevention and management of certain diseases. Recent studies confirmed the potential protective nature of helminth infection against MetS and T2DM via immunomodulation or, potentially, alteration of the intestinal microbiota. This Phase 1b safety and tolerability trial aims to assess the effect of inoculation with helminths on physical and metabolic parameters, immune responses, and the microbiome in otherwise healthy women and men.MethodsParticipants eligible for inclusion are adults aged 18–50 with central obesity and a minimum of one additional feature of MetS recruited from the local community with a recruitment target of 54. In a randomised, double-blind, placebo-controlled design, three groups will receive either 20 or 40 stage three larvae of the human hookworm Necator americanus or a placebo. Eligible participants will provide blood and faecal samples at their baseline and 6-monthly assessment visits for a total of 24 months with an optional extension to 36 months. During each scheduled visit, participants will also undergo a full physical examination and complete diet (PREDIMED), physical activity, and patient health (PHQ-9) questionnaires. Outcome measurements include tolerability and safety of infection with Necator americanus, changes in metabolic and immunological parameters, and changes in the composition of the faecal microbiome.DiscussionRising cost of healthcare associated with obesity-induced metabolic diseases urgently calls for new approaches in disease prevention. Findings from this trial will provide valuable information regarding the potential mechanisms by which hookworms, potentially via alterations in the microbiota, may positively influence metabolic health.Trial registrationThe protocol was registered on ANZCTR.org.au on 05 June 2017 with identifier ACTRN12617000818336.Alternatively, a Google search using the above trial registration number will yield a direct link to the trial protocol within the ANZCTR website.

The cGAS-cGAMP-STING Pathway: A Molecular Link Between Immunity and Metabolism.

It has been appreciated for many years that there is a strong association between metabolism and immunity in advanced metazoan organisms. Distinct immune signatures and signaling pathways have been found not only in immune but also in metabolic cells. The newly discovered DNA-sensing cGAS-cGAMP-STING pathway mediates type I interferon inflammatory responses in immune cells to defend against viral and bacterial infections. Recent studies show that this pathway is also activated by host DNA aberrantly localized in the cytosol, contributing to increased sterile inflammation, insulin resistance, and the development of nonalcoholic fatty liver disease (NAFLD). Potential interactions of the cGAS-cGAMP-STING pathway with mTORC1 signaling, autophagy, and apoptosis have been reported, suggesting an important role of the cGAS-cGAMP-STING pathway in the networking and coordination of these important biological processes. However, the regulation, mechanism of action, and tissue-specific role of the cGAS-cGAMP-STING signaling pathway in metabolic disorders remain largely elusive. It is also unclear whether targeting this signaling pathway is effective for the prevention and treatment of obesity-induced metabolic diseases. Answers to these questions would provide new insights for developing effective therapeutic interventions for metabolic diseases such as insulin resistance, NAFLD, and type 2 diabetes.

The novel designer cytokine IC7Fc protects against obesity-induced metabolic disease

The novel designer cytokine IC7Fc protects against obesity-induced metabolic disease

Effects of treadmill exercise on the regulatory mechanisms of mitochondrial dynamics and oxidative stress in the brains of high-fat diet fed rats.

[Purpose]The purpose of this study was to investigate the effects of treadmill exercise on oxidative stress in the hippocampal tissue and mitochondrial dynamic-related proteins in rats fed a long-term high-fat diet (HFD).[Methods]Obesity was induced in experimental animals using high fat feed, and the experimental groups were divided into a normal diet-control (ND-CON; n=12), a high fat diet-control (HFD-CON; n=12) and a high fat diet-treadmill exercise (HFD-TE; n=12) group. The rats were subsequently subjected to treadmill exercise (progressively increasing load intensity) for 8 weeks (5 min at 8 m/min, then 5 min at 11 m/min, and finally 20 min at 14 m/min). We assessed weight, triglyceride (TG) concentration, total cholesterol (TC), area under the curve, homeostatic model assessment of insulin resistance, and AVF/body weight. Western blotting was used to examine expression of proteins related to oxidative stress and mitochondrial dynamics, and immunohistochemistry was performed to examine the immunoreactivity of gp91phox.[Results]Treadmill exercise effectively improved the oxidative stress in the hippocampal tissue, expression of mitochondrial dynamic-related proteins, and activation of NADPH oxidase (gp91phox) and induced weight, blood profile, and abdominal fat loss.[Conclusion]Twenty weeks of high fat diet induced obesity, which was shown to inhibit normal mitochondria fusion and fission functions in hippocampal tissues. However, treadmill exercise was shown to have positive effects on these pathophysiological phenomena. Therefore, treadmill exercise should be considered during prevention and treatment of obesity-induced metabolic diseases.