Search Results (2,987)

Background/Objectives: Obesity and type 2 diabetes mellitus (T2DM) profoundly disrupt lipid metabolism within local microenvironments of skeletal muscle and its associated connective tissues, including adipose tissue, bone, and fascia. However, the role of local communication between skeletal muscle and its proximal connective tissues in propagating metabolic dysfunction is incompletely understood. This narrative review synthesizes current evidence on these local metabolic interactions, highlighting novel insights and existing gaps. Methods: We conducted a comprehensive literature analysis of primary research published in the last decade, sourced from PubMed, Web of Science, and ScienceDirect. Studies were selected for relevance to skeletal muscle, adipose tissue, fascia, and bone lipid metabolism in the context of obesity and T2DM, with emphasis on molecular, cellular, and paracrine mechanisms of local crosstalk. Findings were organized into thematic sections addressing physiological regulation, pathological remodeling, and inter-organ signaling pathways. Results: Our synthesis reveals that local lipid dysregulation in obesity and T2DM involves altered fatty acid transporter dynamics, mitochondrial overload, fibro-adipogenic remodeling, and compartment-specific adipose tissue dysfunction. Crosstalk via myokines, adipokines, osteokines, bioactive lipids, and exosomal miRNAs integrates metabolic responses across these tissues, amplifying insulin resistance and lipotoxic stress. Emerging evidence highlights the underappreciated roles of fascia and marrow adipocytes in regional lipid handling. Conclusions: Collectively, these insights underscore the pivotal role of inter-tissue crosstalk among skeletal muscle, adipose tissue, bone, and fascia in orchestrating lipid-induced insulin resistance, and highlight the need for integrative strategies that target this multicompartmental network to mitigate metabolic dysfunction in obesity and T2DM. Full article

Exposure to persistent organic pollutants such as 2,3,7,8-tetrachlorodibenzodioxin (TCDD) increases metabolic disorder risk. In this study, we show that a single intraperitoneal injection of TCDD (10 μg/kg) in C57BL/6J mice induced body weight gain, lipid accumulation in the liver and adipose tissue, macrophage infiltration, and elevated hepatic and serum triglyceride levels after 12 weeks. Despite serum aryl hydrocarbon receptor (AhR) ligand levels normalizing by 12 weeks, the persistent effects suggest TCDD sequestration in fat tissue. TCDD inhibited the expression of mitochondrial proteins (COX1, TOM20, TFAM, H2AX) and reduced mitochondrial oxygen consumption. Liver-specific AhR knockout ameliorated TCDD-induced mitochondrial dysfunction, lipid accumulation, and macrophage infiltration. Mechanistically, TCDD-induced hepatic plasminogen activator inhibitor-1 (PAI-1) promoted adipocyte hypertrophy. In the liver, PAI-1 disrupted the interaction between tissue-type plasminogen activator (tPA) and apolipoprotein B (ApoB), thereby enhancing very-low-density lipoprotein (VLDL) assembly. These findings reveal that hepatocyte-derived circulating PAI-1, upregulated via hepatic AhR activation, contributes to adipocyte hypertrophy and hepatosteatosis through the intracellular modulation of the tPA–PAI-1 axis. Thus, hepatic AhR activation drives mitochondrial dysfunction and obesity, even after a single TCDD exposure. Full article

The increasing prevalence of obesity, a chronic disease, necessitates the development and evaluation of evidence-based prevention and intervention strategies tailored to heterogeneous populations. Certain fruits, including papaya and pineapple (Ananas comosus), have been investigated as potential dietary components in obesity management. In the context of obesity and chronic low-grade inflammation, bromelain, a proteolytic enzyme derived from pineapple, is a widely studied phytotherapeutic agent that acts through multiple mechanisms intersecting immune and metabolic pathways. This narrative review summarizes current evidence on the effects of bromelain in obesity, low-grade inflammation, and related metabolic disturbances. Searches of the literature were conducted in Google Scholar, PubMed, and Scopus databases. This review incorporates findings from in vitro, animal, and human studies. We outline the mechanisms and evidence supporting the therapeutic efficacy of bromelain, emphasizing its implications for obesity management in clinical settings. Bromelain has been shown to exert significant anti-inflammatory activity and may modulate adipocyte metabolism, potentially alleviating comorbidities associated with excess adiposity. Although its effects on immune cells are relatively well described, the mechanisms underlying bromelain’s actions on adipocytes remain incompletely understood. Full article

Leptin, an adipocyte-derived hormone, plays a central role in the regulation of energy homeostasis by acting on distinct hypothalamic nuclei. This review explores recent advances in our understanding of leptin’s region-specific actions within the arcuate nucleus, ventromedial hypothalamus, dorsomedial hypothalamus, and lateral hypothalamus, highlighting their contributions to appetite regulation, energy expenditure, and neuroendocrine function. In the hypothalamic arcuate nucleus, leptin’s differential regulation of pro-opiomelanocortin and agouti-related peptide/neuropeptide Y neurons is now complemented by the identification of novel leptin-responsive neuronal populations—such as those expressing prepronociceptin, basonuclin 2, and Pirt—as well as a growing array of cellular and molecular modulators, including secreted factors like angiopoietin-like growth factor, zinc-α2-glycoprotein, and spexin, intracellular regulators such as Rap1, growth factor receptor-bound protein 10, and spliced X-box binding protein 1. In the ventromedial hypothalamus, leptin integrates with both peripheral (e.g., cholecystokinin) and central (e.g., pituitary adenylate cyclase-activating polypeptide) signals, while epigenetic mechanisms, such as those mediated by Jumonji domain-containing protein D3, regulate leptin receptor expression and sensitivity. The dorsomedial hypothalamus is increasingly recognized for coordinating leptin’s effects on metabolism, circadian rhythms, and respiration through distinct neuronal populations, including a subset of neurons co-expressing GLP-1 receptors that mediate leptin’s metabolic effects. In the lateral hypothalamus, leptin modulates reward-driven feeding via GABAergic neuronal populations—circuits that are particularly susceptible to disruption following early life trauma. Together, these insights reveal a sophisticated neurobiological framework through which leptin orchestrates systemic physiology. Understanding the heterogeneity of leptin signaling opens new avenues for restoring leptin sensitivity and developing personalized therapeutic strategies to combat obesity and related metabolic disorders. Full article

Iron is essential for cellular respiration, oxidative defense, and host immunity, but its dysregulation is increasingly associated with metabolic disorders, such as obesity and type 2 diabetes. In these diseases, regional iron accumulation occurs in adipose tissue, independent of systemic overload. This process disrupts the mitochondrial redox balance, induces ferroptotic stress, and activates the innate immune pathways. Recent studies have highlighted the NLRP3 (nucleotide-binding domain, leucine-rich repeat, pyrin domain-containing protein 3) inflammasome and its effector cytokine interleukin-1β (IL-1β) as important mediators of the interface between iron and inflammation. In both adipocytes and macrophages, labile iron increased reactive oxygen species (ROS) production and promoted inflammasome formation. Simultaneously, metabolic stress factors upregulate hepcidin expression, suppress ferroportin activity and exacerbate intracellular iron retention. These molecular events converge to maintain low-grade inflammation and impair insulin signaling. Despite these compelling associations, direct mechanistic evidence remains limited, particularly with respect to depot-specific responses and cell type resolution. In this review, I examine the current evidence linking iron handling and inflammasome biology in adipose tissue, focusing on ferroptosis, thioredoxin-interacting protein (TXNIP) signaling, and spatial mapping of iron–cytokine networks. I also discuss novel therapeutic strategies targeting iron overload and inflammasome activation, including chelation, hepcidin modulation, and inflammasome inhibition in the context of metabolic diseases. Full article

Obesity is an epidemic that currently impacts many nations. The persistence of this disease is shaped by both genetic and epigenetic factors that extend beyond calorie balance. Research in the past year has revealed that epigenetic and cellular memory within adipose tissue can predispose individuals to weight regain after initial fat loss, as shown by studies indicating persistent transcriptional and chromatin changes even after fat mass reduction. Independent studies also demonstrate long-lasting metabolic shifts, such as those triggered by glucose-dependent insulinotropic polypeptide receptor (GIPR)-induced thermogenesis and sarcolipin (SLN) stabilization that also support a form of “metabolic memory” that is associated with sustained weight loss. At the neural level, rare variants in synaptic genes like BSN (Bassoon presynaptic cytomatrix protein), a presynaptic scaffold protein, and APBA1 (amyloid beta precursor protein binding family A member 1), a neuronal adaptor involved in vesicular trafficking, disrupt communication in feeding circuits, elevating obesity risk and illustrating how synaptic integrity influences food intake regulation. Similarly, the spatial compartmentalization of metabolic signaling within neuronal cilia is emerging as crucial, with cilia-localized receptors G protein-coupled receptor 75 (GPR75) and G protein-coupled receptor 45 (GPR45) exerting opposing effects on energy balance and satiety. Meanwhile, genome-wide association studies (GWAS) have advanced through larger, more diverse cohorts and better integration of environmental and biological data. These studies have identified novel obesity-related loci and demonstrated the value of polygenic risk scores (PRS) in predicting treatment responses. For example, genetic variants in GLP-1R (glucagon-like peptide-1 receptor) and GIPR (glucose-dependent insulinotropic polypeptide receptor) may modulate the effectiveness of incretin-based therapies, while PRS for satiation can help match individuals to the most appropriate anti-obesity medications. This review focuses on studies in the last two years that highlight how advances in obesity genetics are driving a shift toward more personalized and mechanism-based treatment strategies. Full article

Objective: Insulin resistance (IR) is a complex and multifactorial disorder that contributes to type 2 diabetes and cardiovascular disease. MicroRNAs (miRNAs) play important roles in diverse developmental and disease processes. However, the molecular mechanisms of IR are unclear. This paper aims to explore the role of miRNA in regulating IR and to elucidate the mechanisms responsible for these effects. Methods: IR models were created by feeding a high-fat diet (HFD) to mice or stimulating 3T3-L1 cells with palmitate. Twelve weeks of HFD trigger weight gain, leading to lipid accumulation and insulin resistance in mice. The expression profiles of miRNAs in adipose tissues (AT) from the HFD-induced mouse models were analyzed. The relationship between miR-221-3p and SOCS1 was determined using dual luciferase reporter gene assays. Metabolic alterations in AT were investigated by real-time PCR and Western blot. Results: miR-221-3p was significantly increased in AT. HFD-induced disturbances in glucose homeostasis were aggravated by miR-221-3p upregulation. The inhibition of miR-221-3p promoted insulin sensitivity including reduced lipid accumulation and the disruption of glucose metabolism. Of note, the 3′-UTR of SOCS1 was found to be a direct target of miR-221-3p. The SOCS1 inhibitor attenuated miR-221-3p-induced increases in IRS-1 phosphorylation, AKT phosphorylation, and GLUT4. miR-221-3p was considered to be involved in the PI3K/AKT signaling pathway, thus leading to increased insulin sensitivity and decreased IR in HFD-fed mice and 3T3-L1 adipocytes. Conclusions: The miR-221-3p/SOCS1 axis in AT plays a pivotal role in the regulation of glucose metabolism, providing a novel target for treating IR and diabetes. Full article

Background: Enhancing adipose tissue functionality is a promising cellular-level approach to combating obesity. White adipose tissue (WAT) can acquire beige or brown adipose tissue (BAT)-like properties, characterized by increased thermogenesis and energy dissipation. While the SIRT1-SRSF10–Lipin-1 axis has been identified in hepatocytes, where Lipin-1 regulates triglyceride metabolism, its role in adipocytes remains unclear. This study aimed to investigate the function of Lipin-1 in 3T3-L1 preadipocytes and its interaction with SIRT1, SRSF10, and PPARγ in promoting browning-like transcriptional responses. Methods: Mouse 3T3-L1 preadipocytes were treated during differentiation with either rosiglitazone (RGZ), the SIRT1 activator SRT1720, or the SIRT1 inhibitor EX527. Gene expression was assessed by real-time PCR, and protein levels were measured using the Simple Western blot system. Data were compared with untreated controls and analyzed using GraphPad Prism. Results: Lipin-1 expression was significantly upregulated by RGZ treatment, alongside increased transcription of Sirt1 and Srsf10, supporting the presence of this regulatory axis in adipocytes. Elevated Srsf10 favored the production of the Lipin-1b isoform, whereas SIRT1 inhibition reversed these effects, confirming its upstream role. Pathway activation further enhanced the expression of browning markers, including Ucp1, Pgc1a, PRDM16, and CIDEA. Conclusions: These findings demonstrate that Lipin-1 interacts with the SIRT1–PPARγ–SRSF10 axis in adipocytes and contributes to the acquisition of beige/brown-like characteristics in WAT. This regulatory pathway may represent a potential target for improving lipid metabolism and metabolic health. Full article

Obesity poses a serious threat to human health, with induced skeletal muscle dysfunction significantly increasing the risk of metabolic syndrome. In obesity, it is known that visceral adipose tissue (VAT) mediates the dysregulation of the adipose–muscle axis through exosome-delivered miRNAs, but the associated regulatory mechanisms remain incompletely elucidated. This study established an AAV-mediated miR-155 obese mouse model and a co-culture system (HFD VAD-evs/RAW264.7 cells/C2C12 cells) to demonstrate that high-fat diet-induced VA-derived extracellular vesicles (HFD VAD-evs) preferentially accumulate in skeletal muscle and induce developmental impairment. HFD VAD-evs disrupt skeletal muscle homeostasis through dual mechanisms: the direct suppression of myoblast development via exosomal miR-155 cargo and the indirect inhibition of myogenesis through macrophage-mediated inflammatory responses in skeletal muscle. Notably, miR-155 inhibition in HFD VAD-evs reversed obesity-associated myogenic deficits. These findings provide novel mechanistic insights into obesity-induced skeletal muscle dysregulation and facilitate potential therapeutic strategies targeting exosomal miRNA signaling. Full article

Background: Postbiotics with anti-adipogenic properties can significantly modify adipocyte metabolism by influencing key cellular pathways involved in lipid accumulation. In preliminary in vitro studies, it is essential to monitor various cellular and subcellular variables, including gene expression and protein synthesis potential, through RT-qPCR analysis. It is also crucial to select internal controls carefully and evaluate their stability for effective normalization and accurate interpretation of the results. Methods: In this study, we assessed the stability of six commonly used housekeeping genes: GAPDH, Actb, HPRT, HMBS, 18S, and 36B4. We analyzed their variability in mature 3T3-L1 adipocytes treated with supernatants from newly isolated Lacticaseibacillus paracasei strains. Our analysis combined classical statistical methods, a ∆Ct analysis, and software algorithms such as geNorm, NormFinder, BestKeeper, and RefFinder. Results: Our stepwise, multiparameter strategy for selecting reference genes led to the exclusion of Actb and 18S as the most variable reference genes. We identified HPRT as the most stable internal control. Additionally, HPRT and HMBS emerged as a stable pair, while the recommended triplet of genes for reliable normalization consists of HPRT, 36B4, and HMBS. Conclusions: The widely used putative genes in similar studies—GAPDH and Actb—did not confirm their presumed stability, which once again emphasizes the need for experimental validation of internal controls to increase the accuracy and reliability of gene expression. Combining a unique biological model—postbiotic-treated adipocytes—with multiple algorithms integrated into a single workflow allows us to provide a methodological template applicable to similar nutritional and metabolic research settings. Full article

The gut microbiota plays a significant role in metabolic diseases such as obesity. We extracted and purified a new type of pectin polysaccharide (mango peel pectin, MPP) from mango (Mangifera indica L.) peel. The structural analysis results reveal that MPP has a molecular weight (Mw) of 6.76 × 10⁵ Da and the mass fractions of the main components were galacturonic acid (21.36%), glucose (8.85%), and arabinose (5.97%). The results of methylation and NMR analyses reveal that the backbone of MPP consisted of →6)-α-D-GalpAOMe-(1→ and →4)-β-D-Glcp-(1→ linkages. Based on the above structural analysis, we further explored the therapeutic effect of MPP on high-fat diet-induced obese mice. The results demonstrate that MPP significantly suppressed body weight and dyslipidemia, reduced liver damage and lipid accumulation, attenuated changes in adipocyte hypertrophy, and improved glucose homeostasis and insulin resistance, with fasting blood glucose (FBG) levels decreasing by more than 12.8%. Furthermore, the modulatory impact of MPP on gut microbiota composition was investigated. MPP treatment significantly enhanced the levels of short-chain fatty acids (SCFAs) by decreasing the amount of Bacillota and reducing the Bacillota/Bacteroidota ratio, especially with an increase in the total SCFA content of over 64%. Meanwhile, MPP treatment encouraged beneficial bacteria to grow (e.g., Bacteroidota, Akkermansia, and Nanasyncoccus), altered the gut microbiome profiles in mice, and decreased the abundance of harmful bacteria (e.g., Paralachnospira, Coproplasma, Pseudoflavonifractor, Parabacteroides, Acetatifactor, and Phocaeicola). Overall, the findings demonstrate for the first time that MPP treats obesity by alleviating dyslipidemia, improving insulin resistance, and regulating gut microbiota to improve the intestinal environment. Full article

Insulin resistance is a key driver of metabolic disorders, including type 2 diabetes and non-alcoholic fatty liver disease (NAFLD), progressing to non-alcoholic steatohepatitis (NASH). This study investigated the effects of geniposide (GP) on insulin sensitivity and hepatic fibrosis in a high-fat diet (HFD)-induced NASH model. C57BL/6 mice were fed an HFD for five weeks and subsequently divided into normal chow (NC), HFD, HFD with GP 50 mg/kg (GP50), and HFD with GP 100 mg/kg (GP100) groups. The treatments were administered orally for 12 weeks. GP treatment significantly reduced body weight as well as epididymal fat and liver weights, while no differences were observed in food intake. Improvements in glucose and lipid metabolism were observed in oral glucose tolerance tests, homeostatic model assessment of insulin resistance (HOMA-IR), and blood lipid profiles. Histological analyses revealed that GP suppressed adipocyte hypertrophy and hepatic lipid accumulation and hepatic fibrosis. To further elucidate molecular mechanisms of GP, quantitative real-time polymerase chain reaction (qRT-PCR) analysis was conducted in the liver tissue. GP downregulated expression of inflammatory markers, including F4/80, tumor necrosis factor (TNF)-α, and interleukin (IL)-6. GP treatment modulated genes involved in insulin signaling including Janus kinase 2 (JAK2), insulin receptor (INSR), insulin receptor substrate 2 (IRS-2), and protein kinase B (AKT1) gene expression levels. This suggests GP suppresses inflammation and mitigates insulin resistance by activating the INSR–IRS2–Akt pathway. Additionally, GP enhanced adenosine monophosphate-activated protein kinase (AMPK) expression, suggesting its potential role in improving glucose and lipid metabolism. In conclusion, GP improves insulin resistance, inflammation, and hepatic fibrosis, highlighting its therapeutic potential for NASH and related metabolic disorders. Full article

Obesity represents a global medical and social challenge characterized by pathological accumulation of adipose tissue as a result of complex interactions among genetic, environmental, and epigenetic factors. Recent studies have highlighted the pivotal role of epigenetic mechanisms in the pathogenesis of this condition, including abnormal DNA methylation of metabolic genes, dysregulation of microRNAs, and chromatin remodeling. These modifications are reversible and can be modulated by dietary, behavioral, and pharmacological interventions. This review provides a comprehensive analysis of tissue-specific epigenetic alterations identified not only in adipocytes and hepatocytes but also in peripheral blood cells, offering promising opportunities for the development of novel diagnostic biomarkers and targeted epigenetic therapeutic strategies. Full article

Obesity and associated metabolic disorders are rising globally, necessitating effective dietary strategies. CKDB-322, a formulation containing Lactiplantibacillus plantarum Q180 and Phaeodactylum tricornutum, was evaluated for anti-obesity efficacy using in vitro adipocyte differentiation and in vivo high-fat-diet (HFD)-induced obese mouse models. In 3T3-L1 cells, CKDB-322 suppressed adipogenesis by downregulating PPARγ and C/EBPα and enhancing glycerol release. In mice, 8 weeks of oral administration—particularly at the CKDB-322-M dose—significantly reduced body weight gain, adiposity, and serum glucose, triglyceride, and cholesterol levels without affecting liver function. Gene expression analysis revealed the strong inhibition of lipogenic markers (SREBP-1c, ACC, and FAS) in addition to activation of the fatty acid oxidation (CPT-1α and PPARα) and energy metabolism (PGC-1α and AMPK) pathways, with the most pronounced effects in the CKDB-322-M group, which also exhibited the greatest reduction in leptin. These molecular effects were confirmed histologically by decreased adipocyte hypertrophy and ameliorated hepatic steatosis. Collectively, these findings demonstrate that CKDB-322 exerts lipid-modulatory effects through multiple pathways, supporting its potential as a novel functional dietary ingredient for obesity and metabolic disorder prevention. Full article

Background: Obesity-associated liver dysfunction is a key feature of metabolic syndrome. Marine by-products, such as fish oils, offer promising dietary interventions. In this study, we aimed to assess the anti-obesity and hepatoprotective effects of herring–saury by-product-derived fermented fish oil—Gwamegi oil (GmO)—and the same oil fermented with Lactobacillus brevis KCCM13538P (GmOLb) in a high-fat-diet (HFD)-induced obese mouse model. Methods: GmO was extracted and fermented. Anti-obesity and hepatoprotective effects were assessed using in vitro and in vivo studies. For the in vivo study, female C57BL/6J mice were fed an HFD supplemented with lard (control), GmO, or GmOLb for 60 days. Metabolic and liver function parameters were assessed. Results: In 3T3-L1 adipocytes, GmOLb significantly reduced lipid accumulation and intracellular triglyceride (TG) levels compared with GmO. In HFD-fed mice, GmOLb significantly reduced body weight gain, ovarian fat mass, serum TG, low-density lipoprotein cholesterol, leptin concentration, atherogenic indices, and cardiac risk factor ratio. Furthermore, it reduced liver damage indicators, including alanine aminotransferase, aspartate aminotransferase, and total bilirubin levels. Conclusions: Fermenting herring–saury oil with L. brevis KCCM13538P enhanced its anti-obesity and hepatoprotective effects in HFD-fed mice. GmOLb shows strong potential as a functional dietary lipid for preventing and managing metabolic disorders. Full article