GLP-1 agonism stimulates brown adipose tissue thermogenesis and browning through hypothalamic AMPK

Bioactive peptides PIISVYWK and FSVVPSPK improve glucose homeostasis by targeting DPP-IV and glucose transport in type 2 diabetic mice

Type 2 Diabetes Mellitus (T2DM) is a metabolic disorder characterized by chronic hyperglycemia, insulin resistance, and progressive β-cell dysfunction, often exacerbated by inflammation and oxidative stress. Effective management requires multi-targeted approaches, including modulation of glucose metabolism, suppression of inflammatory pathways, and pancreatic protection. This study investigates the antidiabetic and immunomodulatory potential of PIISVYWK (P1) and FSVVPSPK (P2), bioactive peptides from blue mussel, Mytilus edulis, in regulating these pathways. In vitro, P1 and P2 were assessed for their ability to inhibit α-glucosidase and DPP-IV activity in Caco-2 cells, alongside glucose uptake and transporter protein expression (SGLT-1 and GLUT2). In vivo, HFD/STZ-induced diabetic mice were administered P1 or P2 (1 mg/kg or 10 mg/kg) or metformin (200 mg/kg) for four weeks. Peptide treatment significantly improved glycemic control by inhibiting α-glucosidase and DPP-IV, increasing GLP-1 levels, and reducing intestinal glucose uptake. Additionally, P1 and P2 exhibited strong anti-inflammatory effects by suppressing NF-κB activation and reducing circulating IL-6, TNF-α, and IL-1β levels. Enhanced antioxidant enzyme activity (SOD, GPx, CAT) further mitigated oxidative stress, preventing pancreatic damage. Peptides also preserved β-cell function by enhancing insulin secretion and regulating glucagon levels. These findings suggest that P1 and P2 peptides exert antidiabetic effects through multi-targeted mechanisms, including immunomodulation, making them promising therapeutic candidates for T2DM management.

Unlocking the multifaceted roles of GLP-1: Physiological functions and therapeutic potential

Glucagon (GCG) like peptide 1 (GLP-1) has emerged as a powerful player in regulating metabolism and a promising therapeutic target for various chronic diseases. This review delves into the physiological roles of GLP-1, exploring its impact on glucose homeostasis, insulin secretion, and satiety. We examine the compelling evidence supporting GLP-1 receptor agonists (GLP-1RAs) in managing type 2 diabetes (T2D), obesity, and other diseases. The intricate molecular mechanisms underlying GLP-1RAs are explored, including their interactions with pathways like extracellular signal-regulated kinase 1/2 (ERK1/2), activated protein kinase (AMPK), cyclic adenine monophosphate (cAMP), mitogen-activated protein kinase (MAPK), and protein kinase C (PKC). Expanding our understanding, the review investigates the potential role of GLP-1 in cancers. Also, microribonucleic acid (RNA) (miRNAs), critical regulators of gene expression, are introduced as potential modulators of GLP-1 signaling. We delve into the link between miRNAs and T2D obesity and explore specific miRNA examples influencing GLP-1R function. Finally, the review explores the rationale for seeking alternatives to GLP-1RAs and highlights natural products with promising GLP-1 modulatory effects.

Mechanisms of GLP-1 Receptor Agonist-Induced Weight Loss: A Review of Central and Peripheral Pathways in Appetite and Energy Regulation

Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) have become central in managing obesity and type 2 diabetes, primarily through appetite suppression and metabolic regulation. This review explores the mechanisms underlying GLP-1 RA-induced weight loss, focusing on central and peripheral pathways. Centrally, GLP-1 RAs modulate brain regions controlling appetite, influencing neurotransmitter and peptide release to regulate hunger and energy expenditure. Peripherally, GLP-1 RAs improve glycemic control by enhancing insulin secretion, reducing glucagon release, delaying gastric emptying, and regulating gut hormones. They also reduce triglycerides and low-density lipoprotein cholesterol, mitigate adipose tissue inflammation, and minimize ectopic fat deposition, promoting overall metabolic health. Emerging dual and triple co-agonists, targeting GLP-1 alongside glucose-dependent insulinotropic polypeptide, and glucagon pathways, may enhance weight loss and metabolic flexibility. Understanding these mechanisms is crucial as the therapeutic landscape evolves, offering clinicians and researchers insights to optimize the efficacy of current and future obesity treatments.

Intestinal Epithelial-Derived Exosomes Under Cold Stimulation Promote Adipose Thermogenesis

Background: Whether intestinal epithelial cells can regulate distant adipose tissue remains a mystery. Methods: Cold-stimulated intestinal epithelial cell-derived exosomes (Cold IEC-Exo) play a pivotal role in enhancing adipose thermogenesis and metabolic homeostasis, as demonstrated in this study. Results: IEC-Exo can accumulate in adipose tissue. Compared with IEC-Exo derived from room temperature mice (RT IEC-Exo), Cold IEC-Exo significantly enhanced the thermogenesis of adipose. In vitro, Cold IEC-Exo directly stimulated thermogenesis in primary adipocytes by elevating oxygen consumption rate, proton leak, and fatty acid uptake, with no effect on glucose uptake. Small RNA sequencing identified miR-674-3p as a key mediator enriched in Cold IEC-Exo. miR-674-3p mimicry replicated Cold IEC-Exo effects, augmenting Ucp1 expression, mitochondrial uncoupling, and fatty acid utilization in adipocytes. Local overexpression of miR-674-3p in BAT and sWAT via AAV in vivo enhanced thermogenesis and attenuated diet-induced glucose intolerance. Conclusions: These findings establish that Cold IEC-Exo, via miR-674-3p transfer, drive adipose thermogenic activation and mitigate metabolic dysfunction, highlighting their therapeutic potential in obesity-related disorders.

Semaglutide and bariatric surgery induce distinct changes in the composition of mouse white adipose tissue

Adipose tissue is a central player in energy balance and glucose homeostasis, expanding in the face of caloric overload in order to store energy safely. If caloric overload continues unabated, however, adipose tissue becomes dysfunctional, leading to systemic metabolic compromise in the form of insulin resistance and type 2 diabetes. Changes in adipose tissue during the development of metabolic disease are varied and complex, made all the more so by the heterogeneity of cell types within the tissue. Here we present detailed comparisons of atlases of murine WAT in the setting of diet-induced obesity, as well as after weight loss induced by either vertical sleeve gastrectomy (VSG) or treatment with the GLP-1 receptor agonist semaglutide. We focus on identifying populations of cells that return to a lean-like phenotype versus those that persist from the obese state, and examine pathways regulated in these cell types across conditions. These data provide a resource for the study of the cell type changes in WAT during weight loss, and paint a clearer picture of the differences between adipose tissue from lean animals that have never been obese, versus those that have.

Glucagon-Like Peptide-1 and Hypothalamic Regulation of Satiation: Cognitive and Neural Insights from Human and Animal Studies

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) have emerged as blockbuster drugs for treating metabolic diseases. Glucagon-like peptide-1 (GLP-1) plays a pivotal role in glucose homeostasis by enhancing insulin secretion, suppressing glucagon release, delaying gastric emptying, and acting on the central nervous system to regulate satiation and satiety. This review summarizes the discovery of GLP-1 and the development of GLP-1RAs, with a particular focus on their central mechanisms of action. Human neuroimaging studies demonstrate that GLP-1RAs influence brain activity during food cognition, supporting a role in pre-ingestive satiation. Animal studies on hypothalamic feed-forward regulation of hunger suggest that cognitive hypothalamic mechanisms may also contribute to satiation control. We highlight the brain mechanisms of GLP-1RA-induced satiation and satiety, including cognitive impacts, with an emphasis on animal studies of hypothalamic glucagon-like peptide-1 receptor (GLP-1R) and GLP-1R-expressing neurons. Actions in non-hypothalamic regions are also discussed. Additionally, we review emerging combination drugs and oral GLP-1RA formulations aimed at improving efficacy and patient adherence. In conclusion, the dorsomedial hypothalamus (DMH)-a key GLP-1RA target-mediates pre-ingestive cognitive satiation, while other hypothalamic GLP-1R neurons regulate diverse aspects of feeding behavior, offering potential therapeutic targets for obesity treatment.

Role of GLP‑1 receptor agonists in sepsis and their therapeutic potential in sepsis‑induced muscle atrophy (Review)

Sepsis‑induced myopathy (SIM) is a common complication in intensive care units, which is often associated with adverse outcomes, primarily manifested as skeletal muscle weakness and atrophy. Currently, the management of SIM focuses on prevention strategies, as effective therapeutic options remain elusive. Glucagon‑like peptide‑1 (GLP‑1) receptor agonists (GLP‑1RAs) have garnered attention as hypoglycemic and weight‑loss agents, with an increasing body of research focusing on the extrapancreatic effects of GLP‑1. In preclinical settings, GLP‑1RAs exert protective effects against sepsis‑related multiple organ dysfunction through anti‑inflammatory and antioxidant mechanisms. Based on the existing research, we hypothesized that GLP‑1RAs may serve potential protective roles in the repair and regeneration of skeletal muscle affected by sepsis. The present review aimed to explore the relationship between GLP‑1RAs and sepsis, as well as their impact on muscle atrophy‑related myopathy. Furthermore, the potential mechanisms and therapeutic benefits of GLP‑1RAs are discussed in the context of muscle atrophy induced by sepsis.

Bariatric surgery promotes recruitment of brown fat linked to alterations in the gut microbiota

OBJECTIVE

The mechanisms of bariatric surgery-induced weight loss and metabolic improvements are still incompletely understood and reach beyond malabsorption or calorie restriction. We sought to investigate the effect of bariatric surgery on brown adipose tissue (BAT) activity and a potential connection with changes in energy metabolism, the gut microbiota, and short-chain fatty acid (SCFA) composition.

METHODS

We included 32 subjects (25 females) with morbid obesity and analyzed their metabolic profile, gut microbiota composition, circulating SCFAs, energy expenditure, and cold-induced BAT activity using [18F]Fluorodeoxyglucose-positron emission tomography-computed tomography before and up to 1 year after bariatric surgery.

RESULTS

Twelve months after surgery, the percentage of individuals with active BAT had increased from 28% to 53%. The BAT-negative (BATneg) individuals who had an adverse metabolic profile at baseline compared with subjects with active BAT (BATpos) showed a greater metabolic benefit after surgery. While no changes in overall gut bacterial diversity were observed between BATpos and BATneg, the abundance of 3 specific bacterial families, including Akkermansiaceae, Pasteurellaceae, and Carnobacteriaceae, was distinctly regulated between BAT groups. The bacterial genera most strongly increased in BATpos vs BATneg subjects were all positively correlated with BAT volume and BAT activity. Finally, circulating concentrations of the SCFAs acetate, butyrate, and propionate rose after bariatric surgery and were related to bacterial genera such as Akkermansia, Dialister, and Lachnospiraceae FCS020 group, all known SCFA producers.

CONCLUSIONS

Bariatric surgery helps recruit active BAT in individuals with obesity and is linked to distinct alterations in the gut microbiome and SCFA composition.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (NCT03168009).

Epicardial Adipose Tissue and Extracellular Volume Fraction in Patients with Hypertrophic Cardiomyopathy: A Multi‑center Prognosis Study

RATIONALE AND OBJECTIVES

Epicardial adipose tissue (EAT) is thought to have a deleterious effect on the progression of myocardial disease; the extracellular volume (ECV) fraction has been validated by histology to correlate with adverse myocardial remodeling. The aim of this study was to investigate the prognostic value of EAT volume index (EATVI) and ECV in patients with hypertrophic cardiomyopathy (HCM).

MATERIALS AND METHODS

ECV and EAT were measured using cardiac magnetic resonance (CMR) imaging in 201 subjects with HCM. All patients were followed up prospectively. Major adverse cardiovascular events (MACEs) were categorized into primary and secondary endpoint events. The primary endpoint was a composite of cardiac death, heart transplant, and cardiopulmonary resuscitation following syncope. The secondary endpoint was defined as rehospitalization for heart failure (HF).

RESULTS

After 26±16 months of follow-up, 43 patients experienced MACEs (14 patients experienced a primary endpoint, and 29 patients experienced a secondary endpoint). Patients suffering from MACEs had significantly higher ECV and EATVI (p<0.001). After adjustment for body mass index (BMI), EATVI showed a significant correlation with ECV (r=0.424, p<0.001) among HCM patients. In the Kaplan-Meier analysis, the incidence of MACE was significantly higher in patients with increased ECV (p<0.001) and higher EATVI (p<0.001). In multivariate Cox regression analysis, ECV (HR=1.12, p<0.001) and EATVI (HR=1.31, p<0.001) were significantly associated with MACEs.

CONCLUSION

In patients with HCM, ECV and EATVI measured by CMR are strong predictors of MACEs and improve risk stratification.

CLINICAL IMPLICATION

Extracellular volume fraction and epicardial adipose tissue are associated with major adverse cardiovascular events in patients with hypertrophic cardiomyopathy and can improve their risk stratification.

The role of epicardial adipose tissue remodelling in heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is a growing global health problem characterized by high morbidity and mortality, with limited effective therapies available. Obesity significantly influences haemodynamic and structural changes in the myocardium and vasculature, primarily through the accumulation and action of visceral adipose tissue. Particularly, epicardial adipose tissue (EAT) contributes to HFpEF through inflammation and lipotoxic infiltration of the myocardium. However, the precise signalling pathways leading to diastolic stiffness in HFpEF require further elucidation. This review explores the dynamic role of EAT in health and disease. Drawing upon insights from studies in other conditions, we discuss potential EAT-mediated inflammatory pathways in HFpEF and how they may contribute to functional and structural myocardial and endothelial derangements, including intramyocardial lipid infiltration, fibrosis, endothelial dysfunction, cardiomyocyte stiffening, and left ventricular hypertrophy. Lastly, we propose potential targets for novel therapeutic avenues.

Targeting central pathway of Glucose-Dependent Insulinotropic Polypeptide, Glucagon and Glucagon-like Peptide-1 for metabolic regulation in obesity and type 2 diabetes

Obesity and type 2 diabetes are significant public health challenges that greatly impact global well-being. The development of effective therapeutic strategies has become more and more concentrated on the central nervous system and metabolic regulation. The primary pharmaceutical interventions for the treatment of obesity and uncontrolled hyperglycemia are now generally considered to be incretin-based anti-diabetic treatments, particularly glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide receptor agonists. This is a result of their substantial influence on the central nervous system and the consequent effects on energy balance and glucose regulation. It is increasingly crucial to understand the neural pathways of these pharmaceuticals. The purpose of this review is to compile and present the most recent central pathways regarding glucagon-like peptide-1, glucose-dependent insulinotropic polypeptide and glucagon receptors, with a particular emphasis on central metabolic regulation.

Weight Reduction with GLP-1 Agonists and Paths for Discontinuation While Maintaining Weight Loss

Worldwide, nearly 40% of adults are overweight and 13% are obese. Health consequences of excess weight include cardiovascular diseases, type 2 diabetes, dyslipidemia, and increased mortality. Treating obesity is challenging and calorie restriction often leads to rebound weight gain. Treatments such as bariatric surgery create hesitancy among patients due to their invasiveness. GLP-1 medications have revolutionized weight loss and can reduce body weight in obese patients by between 15% and 25% on average after about 1 year. Their mode of action is to mimic the endogenous GLP-1, an intestinal hormone that regulates glucose metabolism and satiety. However, GLP-1 drugs carry known risks and, since their use for weight loss is recent, may carry unforeseen risks as well. They carry a boxed warning for people with a personal or family history of medullary thyroid carcinoma or multiple endocrine neoplasia syndrome type 2. Gastrointestinal adverse events (nausea, vomiting, diarrhea) are fairly common while pancreatitis and intestinal obstruction are rarer. There may be a loss of lean body mass as well as premature facial aging. A significant disadvantage of using these medications is the high rate of weight regain when they are discontinued. Achieving success with pharmacologic treatment and then weaning to avoid future negative effects would be ideal.

FAcTs on fire: Exploring thermogenesis

Thermoregulation is a fundamental biological process that allows birds and mammals to maintain a stable internal temperature despite environmental fluctuations, a mechanism shaped by millions of years of evolution. Non-shivering thermogenesis (NST), primarily driven by brown adipose tissue (BAT), plays a central role in thermoregulation by not only helping maintain energy homeostasis but also influencing broader metabolic and physiological processes. Recent research has revealed that BAT thermogenesis is regulated by peripheral hormones and at a central level, with key hypothalamic energy-sensing pathways-such as AMP-activated protein kinase (AMPK) and endoplasmic reticulum (ER) stress-playing critical roles. Beyond its metabolic functions, BAT and NST have emerged as important contributors to tumor biology, offering novel therapeutic strategies for metabolic and oncological diseases. This review explores the intricate mechanisms underpinning NST, including UCP1-dependent thermogenesis and alternative pathways such as creatine cycling, calcium-dependent thermogenesis, and lipid cycling. Emerging evidence further highlights BAT's potential in to modulate tumor metabolism, with pharmacological and genetic approaches showing promise in reshaping the tumor microenvironment. This growing body of knowledge offers exciting prospects for targeting BAT thermogenesis in treating obesity and other metabolic diseases.

Insights into the Roles of GLP-1, DPP-4, and SGLT2 at the Crossroads of Cardiovascular, Renal, and Metabolic Pathophysiology

In recent years, new drugs for the treatment of type 2 diabetes (T2D) have been proposed, including glucagon-like peptide 1 (GLP-1) agonists or sodium-glucose cotransporter 2 (SGLT2) inhibitors and dipeptidyl peptidase-4 (DPP-4) inhibitors. Over time, some of these agents (in particular, GLP-1 agonists and SGLT2 inhibitors), which were initially developed for their glucose-lowering actions, have demonstrated significant beneficial pleiotropic effects, thus expanding their potential therapeutic applications. This review aims to discuss the mechanisms, pleiotropic effects, and therapeutic potential of GLP-1, DPP-4, and SGLT2, with a particular focus on their cardiorenal benefits beyond glycemic control.

Thermogenic adipose tissues: Promising therapeutic targets for metabolic diseases

The ongoing increase in the prevalence of obesity and its comorbidities such as cardiovascular disease, type 2 diabetes (T2D) and dyslipidemia warrants discovery of novel therapeutic options for these metabolic diseases. Obesity is characterized by white adipose tissue expansion due to chronic positive energy balance as a result of excessive energy intake and/or reduced energy expenditure. Despite various efforts to prevent or reduce obesity including lifestyle and behavioral interventions, surgical weight reduction approaches and pharmacological methods, there has been limited success in significantly reducing obesity prevalence. Recent research has shown that thermogenic adipocyte (brown and beige) activation or formation, respectively, could potentially act as a therapeutic strategy to ameliorate obesity and its related disorders. This can be achieved through the ability of these thermogenic cells to enhance energy expenditure and regulate circulating levels of glucose and lipids. Thus, unraveling the molecular mechanisms behind the formation and activation of brown and beige adipocytes holds the potential for probable therapeutic paths to combat obesity. In this review, we provide a comprehensive update on the development and regulation of different adipose tissue types. We also emphasize recent interventions in harnessing therapeutic potential of thermogenic adipocytes by bioactive compounds and new pharmacological anti-obesity agents.

Mechanistic insights into GLP-1 receptor agonist-induced weight loss through ceRNA network analysis

BACKGROUND

GLP-1 receptor agonists (GLP-1RA) have been extensively utilized in the management of body weight in individuals with obesity. Circular RNA (circRNA), a class of covalently closed RNA molecules, has garnered increasing attention for its potential role in the pathogenesis of obesity. However, the specific mechanisms through which circRNA contributes to GLP-1RA-induced weight loss remains elusive.

METHODS

High-throughput sequencing analyzed epididymal adipose tissue from obese mice under high-fat, and GLP-1RA intervention (600 μg/kg/d). The functions of differentially expressed (DE) genes were enriched and analyzed. The circRNA-miRNA-mRNA interaction network was constructed in Cytoscape, and KEGG pathway gene enrichment was validated via western blotting.

RESULTS

A total of 644 DEcircRNAs, 186 DEmiRNAs, and 3474 DEmRNAs were identified. Based on ceRNA score calculations, network diagrams were constructed. Gene Ontology (GO) analysis revealed that DERNAs were linked to lipid and fatty acid metabolism. DE genes within ceRNA pairs were enriched in lipid metabolism pathways, especially the PI3K-Akt and AMPK signaling pathways. GLP-1RA induced the phosphorylation of AKT and AMPK, which subsequently led to a reduction of SREBP-1, ACC, and FAS.

CONCLUSION

GLP-1RA might activate PI3K-Akt and AMPK signaling pathways to combat obesity through the ceRNA network of circRNAs.

The effect of obesity pharmacotherapy on body composition, including muscle mass

Obesity pharmacotherapy represents a promising approach to treating obesity and may provide benefits beyond weight loss alone. Maintaining or even increasing muscle mass during weight loss is important to overall health, metabolic function and weight loss maintenance. Drugs such as liraglutide, semaglutide, tirzepatide, and naltrexone/bupropion have shown significant weight loss effects, and emerging evidence suggests they may also have effects on body composition, particularly a positive influence on muscle mass. However, further research is needed to fully understand the mechanism of action of these drugs and their effects on muscle mass. Clinicians should consider these factors when developing an obesity treatment plan for an individual patient.

Enhanced thermogenesis in PAS Kinase-deficient male mice

PAS domain-containing serine/threonine-protein kinase (PASK) is a nutrient and energy sensor regulated by fasting/refeeding conditions in hypothalamic areas involved in controlling energy balance. In this sense, PASK plays a role in coordinating the activation/inactivation of AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR) in response to fasting. PASK deficiency protects against the development of diet-induced obesity. This has prompted an investigation into the potential role of PASK on energy expenditure through thermogenesis in adipose tissue. Our results indicate that PASK-deficient male mice exhibited higher brown adipose tissue (BAT) thermogenic activity and heat production. The inhibition of PASK function induces the expression of Uncoupling Protein 1 (UCP1) and the adipogenic marker peroxisome proliferator-activated receptor gamma (PPARγ) in BAT. In addition, PASK deficiency promotes the expression of UCP1 and other browning markers such as PR/SET Domain 16 (PRDM16) in inguinal white adipose tissue (WAT). PASK-deficient mice record an enhanced thermogenic response, even under stimuli such as β-3adrenergic receptor agonist or cold. This evidence reveals PASK as a new mechanism modulating BAT thermogenesis.

Effect of Hypoglycemic Drugs on Patients with Heart Failure with or without T2DM: A Bayesian Network Meta-analysis

Background

Anti-diabetic drugs have been noted to have a cardioprotective effect in patients with diabetes and heart failure (HF). The purpose of this study was to perform a Bayesian network meta-analysis to evaluate the impact of various anti-diabetic drugs on the prognosis of HF patients with and without diabetes.

Methods

We searched PubMed, Embase, Cochrane, and Web of Science for randomized controlled trials (RCTs) published before November 2024 that investigated the use of anti-diabetic medications in patients with HF. Primary outcomes included re-admission due to HF, all-cause death, cardiovascular death, serum N-terminal pro-brain natriuretic peptide (NTpro-BNP) levels, and left ventricular ejection fraction (LVEF). A Bayesian network meta-analysis was used to compare the effectiveness of different anti-diabetic drugs.

Results

A total of 33 RCTs involving 29,888 patients were included. Sotagliflozin was the most effective in reducing the risk of re-admission due to HF and all-cause death, with a cumulative probability of 0.84 and 0.83, respectively. Liraglutide reduced the risk of cardiovascular death in HF patients with a cumulative probability of 0.97 and had the best efficacy in reducing NTpro-BNP levels with a cumulative probability of 0.69. Empagliflozin was best in improving LVEF in HF patients, with a cumulative probability of 0.69.

Conclusions

This Bayesian network meta-analysis demonstrates that sotagliflozin may be the best option for HF patients with and without diabetes. However, due to the small number of articles in this study, our results must be treated cautiously. Subsequently, there is an urgent need for more high-quality studies to validate our findings.

Nmnat2 deficiency in the arcuate nucleus or paraventricular nucleus induces Sarm1-independent neuron loss and liraglutide-reversible obesity

Nicotinamide mononucleotide adenylyltransferase 2 (Nmnat2) plays an important role in maintaining axon integrity, and the arcuate nucleus (ARC), and paraventricular nucleus (PVN) are crucial nuclei in the control of energy balance. However, the effect of Nmnat2 deficiency in ARC and PVN is still unclear. Nmnat2 loxP/loxP or Nmnat2 loxP/loxP , Sarm1 -/- mice were bilaterally injected with AAV-CMV-GFP-Cre once into the ARC, PVN, or lateral parabrachial nucleus (LPBN) to obtain Nmnat2 ARC-/- , Nmnat2 PVN-/- , Nmnat2 LPBN-/- , Nmnat2 ARC-/- , SKO, Nmnat2 PVN-/- , SKO, or Nmnat2 LPBN-/- , SKO mice. Syn1-Cre mice were bilaterally injected with AAV-EF1a-flex-taCasp3-TEVp once into the ARC or PVN to specifically induce neuron loss. Metabolic changes were measured in the mice intraperitoneally injected with or without liraglutide, a glucagon-like peptide-1 (GLP-1) analog. Neuron loss and neuron activation were monitored by immunofluorescence. Deletion of Nmnat2 in ARC or PVN of mice leads to neuron loss, increased food intake, and obesity in a Sarm1-independent manner. Intraperitoneal injection of liraglutide activates neurons in PVN and LPBN, and attenuates hyperphagia and obesity induced by Nmnat2 deletion or apoptosis of Syn1-positive neurons in ARC or PVN, but has no significant effect on neuron loss. Nmnat2 deficiency in LPBN leads to death within 2 weeks, which can be markedly rescued by Sarm1 deficiency. These data show that deletion of Nmnat2 in ARC or PVN in adult mice leads to Sarm1-independent neuron loss, and liraglutide-reversible hyperphagia and obesity. These findings also elucidate the integrated role of ARC or PVN for downregulating food intake, the requirement of LPBN for survival, and the ARC- or PVN-independent effect of GLP-1 on food intake.

An oral liraglutide nanomicelle formulation conferring reduced insulin-resistance and long-term hypoglycemic and lipid metabolic benefits

Type 2 diabetes is a chronic disease characterized by insulin resistance and often worsened by obesity. Effective management involves the use of glucagon-like peptide-1 receptor agonists (GLP-1 RAs) to assist with glycemic control and weight management. However, these drugs must be administered subcutaneously due to their low oral bioavailability. We developed an oral liraglutide (LRG) formulation by electrostatic complexation of GLP-1 RA with bile acid derivatives and nanomicelle (NM) formation, with non-ionic surfactant n-dodecyl-β-d-maltoside (DDM). The optimized formulation, LDD[1:2:4]-NM, had a mean particle size of 75.9 ± 5.60 nm and a permeability 1347 % higher than that of unformulated LRG when tested in Caco-2/HT29-MTX-E12 cell monolayers. In rats, oral bioavailability was 4.63-fold higher than that of unformulated LRG (1.11 ± 0.20 % vs. 5.14 ± 0.63 %). The absorption mechanism included clathrin-mediated endocytosis, macropinocytosis, and an ASBT-mediated pathway. A 12-week oral treatment consisting of a daily dose of 20 mg LDD[1:2:4]-NM/kg significantly reduced glycohemoglobin levels, a marker of diabetic control, and the HOMA-IR index, a marker of insulin resistance. The weight of epididymal and inguinal white adipose tissue and brown adipose tissue (BAT) was also reduced. Moreover, LDD[1:2:4]-NM had a greater impact on BAT activation, pro-inflammatory gene expression, and lipid metabolism than subcutaneous LRG. This study showed that an oral NM formulation can efficiently deliver LRG. Long-term treatment led to improved hyperglycemic effects, insulin resistance, and modulated lipid metabolism. LDD[1:2:4]-NM is thus a promising oral therapeutic option for the management of type 2 diabetes, potentially transforming treatment paradigms based on the availability of a more convenient administration route.

A Hypothesis That Glucagon-like Peptide-1 Receptor Agonists Exert Immediate and Multifaceted Effects by Activating Adenosine Monophosphate-Activate Protein Kinase (AMPK)

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) reduce bodyweight and blood glucose. Extensive evidence from randomized controlled trials has indicated that GLP-1RAs have benefits well beyond weight loss and glucose control, extending from reductions in cardiovascular mortality to reductions in prostate cancer risk. Notably, some benefits of GLP-1RAs for the cardiovascular-kidney-metabolic (CKM) system arise before weight loss occurs for reasons that are not entirely clear but are key to patient care and drug development. Here, we hypothesize that GLP-1RAs act by inducing calorie restriction and by activating adenosine monophosphate-activated protein kinase (AMPK), which not only provides an explanation for the unique effectiveness of GLP-1RAs but also indicates a common mechanism shared by effective CKM therapies, including salicylates, metformin, statins, healthy diet, and physical activity. Whether AMPK activation is obligatory for effective CKM therapies should be considered. As such, we propose a mechanism of action for GLP-1RAs and explain how it provides an overarching framework for identifying means of preventing and treating cardiovascular, kidney, metabolic and related diseases, as well as informing the complementary question as to the components of a healthy lifestyle.

Effects of Weight Loss on Endothelium and Vascular Homeostasis: Impact on Cardiovascular Risk

Available knowledge shows that obesity is associated with an impaired endothelial function and an increase in cardiovascular risk, but the mechanisms of this association are not yet fully understood. Adipose tissue dysfunction, adipocytokines production, along with systemic inflammation and associated comorbidities (e.g., diabetes and hypertension), are regarded as the primary physiological and pathological factors. Various strategies are now available for the control of excess body weight. Dietary regimens alone, or in association with bariatric surgery when indicated, are now widely used. Of particular interest is the understanding of the effect of these interventions on endothelial homeostasis in relation to cardiovascular health. Substantial weight loss resulting from both diet and bariatric surgery decreases circulating biomarkers and improves endothelial function. Extensive clinical trials and meta-analyses show that bariatric surgery (particularly gastric bypass) has more substantial and long-lasting effect on weight loss and glucose regulation, as well as on distinct circulating biomarkers of cardiovascular risk. This review summarizes the current understanding of the distinct effects of diet-induced and surgery-induced weight loss on endothelial function, focusing on the key mechanisms involved in these effects.

Integration of Glucagon-Like Peptide 1 Receptor Actions Through the Central Amygdala

Understanding the detailed mechanism of action of glucagon-like peptide 1 receptor (GLP-1R) agonists on distinct topographic and genetically defined brain circuits is critical for improving the efficacy and mitigating adverse side effects of these compounds. In this mini-review, we propose that the central nucleus of the amygdala (CeA) is a critical mediator of GLP-1R agonist-driven hypophagia. Here, we review the extant literature demonstrating CeA activation via GLP-1R agonists across multiple species and through multiple routes of administration. The precise role of GLP-1Rs within the CeA is unclear but the site-specific GLP-1Rs may mediate distinct behavioral and physiological hallmarks of GLP-1R agonists on food intake. Thus, we propose important novel directions and methods to test the role of the CeA in mediating GLP-1R actions.

Novel neural pathways targeted by GLP-1R agonists and bariatric surgery

The glucagon-like peptide 1 receptor (GLP-1R) agonist semaglutide has revolutionized the treatment of obesity, with other gut hormone-based drugs lined up that show even greater weight-lowering ability in obese patients. Nevertheless, bariatric surgery remains the mainstay treatment for severe obesity and achieves unparalleled weight loss that generally stands the test of time. While their underlying mechanisms of action remain incompletely understood, it is clear that the common denominator between GLP-1R agonists and bariatric surgery is that they suppress food intake by targeting the brain. In this Review, we highlight recent preclinical studies using contemporary neuroscientific techniques that provide novel concepts in the neural control of food intake and body weight with reference to endogenous GLP-1, GLP-1R agonists, and bariatric surgery. We start in the periphery with vagal, intestinofugal, and spinal sensory nerves and then progress through the brainstem up to the hypothalamus and finish at non-canonical brain feeding centers such as the zona incerta and lateral septum. Further defining the commonalities and differences between GLP-1R agonists and bariatric surgery in terms of how they target the brain may not only help bridge the gap between pharmacological and surgical interventions for weight loss but also provide a neural basis for their combined use when each individually fails.

Glucagon-Like Peptide-1 Links Ingestion, Homeostasis, and the Heart

Glucagon-like peptide-1 (GLP-1), a hormone released from enteroendocrine cells in the distal small and large intestines in response to nutrients and other stimuli, not only controls eating and insulin release, but is also involved in drinking control as well as renal and cardiovascular functions. Moreover, GLP-1 functions as a central nervous system peptide transmitter, produced by preproglucagon (PPG) neurons in the hindbrain. Intestinal GLP-1 inhibits eating by activating vagal sensory neurons directly, via GLP-1 receptors (GLP-1Rs), but presumably also indirectly, by triggering the release of serotonin from enterochromaffin cells. GLP-1 enhances glucose-dependent insulin release via a vago-vagal reflex and by direct action on beta cells. Finally, intestinal GLP-1 acts on the kidneys to modulate electrolyte and water movements, and on the heart, where it provides numerous benefits, including anti-inflammatory, antiatherogenic, and vasodilatory effects, as well as protection against ischemia/reperfusion injury and arrhythmias. Hindbrain PPG neurons receive multiple inputs and project to many GLP-1R-expressing brain areas involved in reward, autonomic functions, and stress. PPG neuron-derived GLP-1 is involved in the termination of large meals and is implicated in the inhibition of water intake. This review details GLP-1's roles in these interconnected systems, highlighting recent findings and unresolved issues, and integrating them to discuss the physiological and pathological relevance of endogenous GLP-1 in coordinating these functions. As eating poses significant threats to metabolic, fluid, and immune homeostasis, the body needs mechanisms to mitigate these challenges while sustaining essential nutrient intake. Endogenous GLP-1 plays a crucial role in this "ingestive homeostasis."

Sucrose-preferring gut microbes prevent host obesity by producing exopolysaccharides

Commensal bacteria affect host health by producing various metabolites from dietary carbohydrates via bacterial glycometabolism; however, the underlying mechanism of action remains unclear. Here, we identified Streptococcus salivarius as a unique anti-obesity commensal bacterium. We found that S. salivarius may prevent host obesity caused by excess sucrose intake via the exopolysaccharide (EPS) -short-chain fatty acid (SCFA) -carbohydrate metabolic axis in male mice. Healthy human donor-derived S. salivarius produced high EPS levels from sucrose but not from other sugars. S. salivarius abundance was significantly decreased in human donors with obesity compared with that in healthy donors, and the EPS-SCFA bacterial carbohydrate metabolic process was attenuated. Our findings reveal an important mechanism by which host-commensal interactions in glycometabolism affect energy regulation, suggesting an approach for preventing lifestyle-related diseases via prebiotics and probiotics by targeting bacteria and EPS metabolites.

Sarcopenia and cachexia: molecular mechanisms and therapeutic interventions

Sarcopenia is defined as a muscle-wasting syndrome that occurs with accelerated aging, while cachexia is a severe wasting syndrome associated with conditions such as cancer and immunodeficiency disorders, which cannot be fully addressed through conventional nutritional supplementation. Sarcopenia can be considered a component of cachexia, with the bidirectional interplay between adipose tissue and skeletal muscle potentially serving as a molecular mechanism for both conditions. However, the underlying mechanisms differ. Recognizing the interplay and distinctions between these disorders is essential for advancing both basic and translational research in this area, enhancing diagnostic accuracy and ultimately achieving effective therapeutic solutions for affected patients. This review discusses the muscle microenvironment's changes contributing to these conditions, recent therapeutic approaches like lifestyle modifications, small molecules, and nutritional interventions, and emerging strategies such as gene editing, stem cell therapy, and gut microbiome modulation. We also address the challenges and opportunities of multimodal interventions, aiming to provide insights into the pathogenesis and molecular mechanisms of sarcopenia and cachexia, ultimately aiding in innovative strategy development and improved treatments.

Liraglutide modulates lipid metabolism via ZBTB20-LPL pathway

OBJECTIVE

To investigate the mechanism of liraglutide affecting lipid metabolism by regulating lipolysis and lipogenesis in cells and ob/ob mice.

METHODS

3 T3-L1 cells were treated with liraglutide in vitro, and differentially expressed genes were screened by RNA sequencing. Gene Ontology (GO) and KEGG (Kvoto Encyclopedia of Genes and Genomes) enrichment analyses identified target genes for lipid regulation of liraglutide. 3 T3-L1 preadipocytes were induced to differentiate into adipocytes using a "cocktail method". Western blot and immunofluorescence were used to detect the expression of target genes and the lipid regulatory effect of liraglutide. 3 T3-L1 preadipocytes were transfected with lentivirus overexpressing Zbtb20 to study its role in adipogenesis, and gene expression was analyzed by RT-qPCR and Western blot. In vivo, ob/ob mice were subcutaneously injected with liraglutide or saline for 4 weeks. Blood lipids, adipose tissue volume and adipocyte size were detected. Immunohistochemical analysis and RT-qPCR were used to detect the expression of target genes in adipose tissue.

RESULTS

Liraglutide reduced lipid droplets and TG levels and altered the expression of genes related to fatty acid metabolism, lipogenesis, fatty acid oxidation, and adipocyte browning. The results of PCR, Western blot and immunofluorescence confirmed that liraglutide could regulate the adipogenesis by downregulating the transcriptional suppressor ZBTB20, and overexpression of Zbtb20 inhibited the expression of LPL, the key enzyme for lipohydrolysis.

CONCLUSIONS

Liraglutide regulates lipid metabolism through ZBTB20-LPL pathway to reveal its molecular mechanism.

Intestinal butyric acid-mediated disruption of gut hormone secretion and lipid metabolism in vasopressin receptor-deficient mice

OBJECTIVES

Arginine vasopressin (AVP), known as an antidiuretic hormone, is also crucial in metabolic homeostasis. Although AVP receptor-deficient mice exhibit various abnormalities in glucose and lipid metabolism, the mechanism underlying these symptoms remains unclear. This study aimed to explore the involvement of the gut hormones including glucagon-like peptide-1 (GLP-1) and microbiota as essential mediators.

METHODS

We used the mouse GLP-1-secreting cell line, GLUTag, and performed live cell imaging to examine the contribution of V1a and V1b vasopressin receptors (V1aR and V1bR, respectively) to GLP-1 secretion. We next investigated the hormone dynamics of V1aR-deficient mice (V1aR-/- mice), V1bR-deficient mice (V1bR-/- mice), and V1aR/V1bR-double deficient mice (V1aR-/-V1bR-/-mice).

RESULTS

AVP induced the increase in intracellular Ca2+ levels and GLP-1 secretion from GLUTag cells in a V1aR and V1bR-dependent manner. AVP receptor-deficient mice, particularly V1aR-/-V1bR-/- mice, demonstrated impaired secretion of GLP-1 and peptide YY secreted by enteroendocrine L cells. V1aR-/-V1bR-/-mice also exhibited abnormal lipid accumulation in the brown adipose tissue and skeletal muscle. We discovered that V1aR-/-V1bR-/- mice showed increased Paneth cell-related gene expression in the small intestine, which was attributed to increased fecal butyric acid levels. Exposure to butyric acid reduced GLP-1 secretion in L cell line. Additionally, human Paneth cell-related gene expressions negatively correlated with that of V1 receptor genes.

CONCLUSIONS

The deficiency in V1 receptor genes may increase gut butyric acid levels and impair the function of L cells, thus dysregulating lipid homeostasis in the brown adipose tissue and skeletal muscle. This study highlights the importance of appropriate control of the gut microbiota and its metabolites, including butyric acid, for the optimum functioning of enteroendocrine cells.

Brown and Beige Adipose Tissue: One or Different Targets for Treatment of Obesity and Obesity-Related Metabolic Disorders?

The failure of the fight against obesity makes us turn to new goals in its treatment. Now, brown adipose tissue has attracted attention as a promising target for the treatment of obesity and associated metabolic disorders such as insulin resistance, dyslipidemia, and glucose tolerance disorders. Meanwhile, the expansion of our knowledge has led to awareness about two rather different subtypes: classic brown and beige (inducible brown) adipose tissue. These subtypes have different origin, differences in the expression of individual genes but also a lot in common. Both tissues are thermogenic, which means that, by increasing energy consumption, they can improve their balance with excess intake. Both tissues are activated in response to specific inducers (cold, beta-adrenergic receptor activation, certain food and drugs), but beige adipose tissue transdifferentiates back into white adipose tissue after the cessation of inducing action, while classic brown adipose tissue persists, but its activity decreases. In this review, we attempted to understand whether there are differences in the effects of different groups of thermogenesis-affecting drugs on these tissues. The analysis showed that this area of research is rather sparse and requires close attention in further studies.

Interplay between the brain and adipose tissue: a metabolic conversation

The central nervous system and adipose tissue interact through complex communication. This bidirectional signaling regulates metabolic functions. The hypothalamus, a key homeostatic brain region, integrates exteroceptive and interoceptive signals to control appetite, energy expenditure, glucose, and lipid metabolism. This regulation is partly achieved via the nervous modulation of white (WAT) and brown (BAT) adipose tissue. In this review, we highlight the roles of sympathetic and parasympathetic innervation in regulating WAT and BAT activities, such as lipolysis and thermogenesis. Adipose tissue, in turn, plays a dual role as an energy reservoir and an endocrine organ, secreting hormones that influence brain function and metabolic health. In addition, this review focuses on recently uncovered communication pathways, including extracellular vesicles and neuro-mesenchymal units, which add new layers of regulation and complexity to the brain-adipose tissue interaction. Finally, we also examine the consequences of disrupted communication between the brain and adipose tissue in metabolic disorders like obesity and type-2 diabetes, emphasizing the potential for new therapeutic strategies targeting these pathways to improve metabolic health.

Liraglutide prevents body and fat mass gain in ovariectomized Wistar rats

Estrogens exert beneficial metabolic effects by reducing food intake and enhancing energy expenditure through both central and peripheral mechanisms. The decrease of estrogen, as occurs in ovariectomy (OVX), leads to metabolic disturbances, such as increased body weight, adipose tissue mass, basal blood glucose, and impaired glucose tolerance. These effects can be reversed by reintroducing estrogen. GLP-1 and its receptor agonists, known for their antihyperglycemic properties, also exhibit anorexigenic effects. Besides that, research indicates that GLP-1 analogs can induce metabolic changes peripherally, such as increased fatty acid oxidation and inhibited lipogenesis. Given the shared metabolic actions of GLP-1 and estrogens, we explored whether liraglutide, a GLP-1 agonist, could mitigate the metabolic effects of estrogen deficiency. We tested this hypothesis using ovariectomized rats, a model that simulates menopausal estrogen deficiency, and treated them with either liraglutide or 17β-Estradiol benzoate for 21 days. Ovariectomy resulted in elevated DPP-IV activity in both plasma and inguinal white adipose tissue (iWAT). While estrogen replacement effectively countered the DPP-IV increase in both plasma and iWAT, liraglutide only prevented the rise in iWAT DPP-IV activity. Liraglutide prevented body weight and fat mass gain after ovariectomy to the same extent as estradiol treatment. This can be explained by the lower food intake and food efficiency caused by estradiol and liraglutide. However, liraglutide was associated with increased pro-inflammatory cytokines and inflammatory cells in white adipose tissue. Further research is crucial to fully understand the potential benefits and risks of using GLP-1 receptor agonists in the context of menopause.

Interactions between glucagon like peptide 1 (GLP-1) and estrogens regulates lipid metabolism

Obesity, characterized by excessive fat accumulation in white adipose tissue (WAT), is linked to numerous health issues, including insulin resistance (IR), and type 2 diabetes mellitus (DM2). The distribution of adipose tissue differs by sex, with men typically exhibiting android adiposity and pre-menopausal women displaying gynecoid adiposity. After menopause, women have an increased risk of developing android-type obesity, IR, and DM2. Glucagon-like peptide 1 (GLP-1) receptor agonists (GLP-1RAs) are important in treating obesity and DM2 by regulating insulin secretion, impacting glucose and lipid metabolism. GLP-1Rs are found in various tissues including the pancreas, brain, and adipose tissue. Studies suggest GLP-1RAs and estrogen replacement therapies have similar effects on tissues like the liver, central nervous system, and WAT, probably by converging pathways involving protein kinases. To investigate these interactions, female rats underwent ovariectomy (OVR) to promote a state of estrogen deficiency. After 20 days, the rats were euthanized and the tissues were incubated with 10 μM of liraglutide, a GLP-1RA. Results showed significant changes in metabolic parameters: OVR increased lipid catabolism in perirenal WAT and basal lipolysis in subcutaneous WAT, while liraglutide treatment enhanced stimulated lipolysis in subcutaneous WAT. Liver responses included increased stimulated lipolysis with liraglutide. Transcriptome analysis revealed distinct gene expression patterns in WAT of OVR rats and those treated with GLP-1RA, highlighting pathways related to lipid and glucose metabolism. Functional enrichment analysis showed estrogen's pivotal role in these pathways, influencing genes involved in lipid metabolism regulation. Overall, the study underscores GLP-1RA acting directly on adipose tissues and highlights the complex interactions between GLP-1 and estrogen in regulating metabolism, suggesting potential synergistic therapeutic effects in treating metabolic disorders like obesity and DM2.

Cross-talk between adipose tissue and microbiota-gut-brain-axis in brain development and neurological disorder

The gut microbiota is an important factor responsible for the physiological processes as well as pathogenesis of host. The communication between central nervous system (CNS) and microbiota occurs by different pathways i.e., chemical, neural, immune, and endocrine. Alteration in gut microbiota i.e., gut dysbiosis causes alteration in the bidirectional communication between CNS and gut microbiota and linked to the pathogenesis of neurological and neurodevelopmental disorder. Therefore, now-a-days microbiota-gut-brain-axis (MGBA) has emerged as therapeutic target for the treatment of metabolic disorder. But, experimental data available on MGBA from basic research has limited application in clinical study. In present study we first summarized molecular mechanism of microbiota interaction with brain physiology and pathogenesis via collecting data from different sources i.e., PubMed, Scopus, Web of Science. Furthermore, evidence shows that adipose tissue (AT) is active during metabolic activities and may also interact with MGBA. Hence, in present study we have focused on the relationship among MGBA, brown adipose tissue, and white adipose tissue. Along with this, we have also studied functional specificity of AT, and understanding heterogeneity among MGBA and different types of AT. Therefore, molecular interaction among them may provide therapeutic target for the treatment of neurological disorder.

Glucagon-like peptide-1 receptor agonist semaglutide reduces atrial fibrillation incidence: A systematic review and meta-analysis

BACKGROUND

Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are new anti-hyperglycaemic drugs with proven cardiovascular (CV) benefit in diabetic and non-diabetic patients at high CV risk. Despite a neutral class effect on arrhythmia risk, data on semaglutide suggest a possible drug-specific benefit in reducing atrial fibrillation (AF) occurrence.

OBJECTIVE

To perform a meta-analysis of randomized clinical trials (RCTs) to assess the risk of incident AF in patients treated with semaglutide compared to placebo.

METHODS AND RESULTS

Ten RCTs were included in the analysis. Study population encompassed 12,651 patients (7285 in semaglutide and 5366 in placebo arms), with median follow-up of 68 months. A random effect meta-analytic model was adopted to pool relative risk (RR) of incident AF. Semaglutide reduces the risk of AF by 42% (RR .58, 95% CI .40-.85), with low heterogeneity across the studies (I2 0%). At subgroup analysis, no differences emerged between oral and subcutaneous administration (oral: RR .53, 95% CI .23-1.24, I2 0%; subcutaneous: RR .59, 95% CI .39-.91, I2 0%; p-value .83). In addition, meta-regression analyses did not show any potential influence of baseline study covariates, in particular the proportion of diabetic patients (p-value .14) and body mass index (BMI) (p-value .60).

CONCLUSIONS

Semaglutide significantly reduces the occurrence of incident AF by 42% as compared to placebo in individuals at high CV risk, mainly affected by type 2 diabetes mellitus. This effect appears to be consistent independently of the route of administration of the drug (oral or subcutaneous), the presence of underlying diabetes and BMI.

Berberine-induced glucagon-like peptide-1 and its mechanism for controlling type 2 diabetes mellitus: a comprehensive pathway review

INTRODUCTION

A growing number of studies have thus far showed the association between type 2 diabetes mellitus (DM) and the intestinal microbiome homoeostasis. As reported, the gut microflora can be significantly different in patients with type 2 DM (T2DM) compared to those in healthy individuals.

METHODS

The authors collected the relevant articles published until 2022 and these are carefully selected from three scientific databases based on keywords.

DISCUSSION

This review highlights research on the anti-diabetic properties of berberine (BBR)-induced glucagon-like peptide-1 (GLP-1), as a glucose-lowering factor and a balance regulator in the microbial flora of the intestines, which plays an important role in adjusting the signalling pathways affecting insulin secretion.

RESULTS

Considering the anti-diabetic characteristics of the BBR-induced GLP-1, BBR makes a promising complementary treatment for reducing the clinical symptoms of DM by reducing the hyperglycaemia. Berberin might be a safe and effective drug for T2DM with little or no adverse effects.

Rheumatic diseases and metabolism: where centre and periphery meet

Over the past few decades, the connection between metabolism and various inflammatory and rheumatic diseases has been an area of active investigation. Nonetheless, the precise mechanisms underlying these relationships remain a topic of ongoing debate, owing in part to conflicting data. This discrepancy can be attributed to the predominant focus on peripheral mechanisms in research into the metabolic consequences of rheumatic diseases. However, a wealth of evidence supports the notion that the central nervous system, specifically the hypothalamus, has an important influence on metabolic homeostasis. Notably, links have been established between crucial hypothalamic mechanisms responsible for regulating energy balance (including food intake, thermogenesis, and glucose and lipid metabolism), such as AMP-activated protein kinase, and the pathophysiology of rheumatoid arthritis. This Review aims to comprehensively examine the current understanding of central metabolic control in rheumatic diseases and explore potential therapeutic options that target this pathophysiological mechanism.

The β3-Adrenergic Receptor: Structure, Physiopathology of Disease, and Emerging Therapeutic Potential

The discovery and characterization of the signal cascades of the β-adrenergic receptors have made it possible to effectively target the receptors for drug development. β-Adrenergic receptors are a class A rhodopsin type of G protein-coupled receptors (GPCRs) that are stimulated mainly by catecholamines and therefore mediate diverse effects of the parasympathetic nervous system in eliciting "fight or flight" type responses. They are detectable in several human tissues where they control a plethora of physiological processes and therefore contribute to the pathogenesis of several disease conditions. Given the relevance of the β-adrenergic receptor as a molecular target for many pathological conditions, this comprehensive review aims at providing an in-depth exploration of the recent advancements in β3-adrenergic receptor research. More importantly, we delve into the prospects of the β3-adrenergic receptor as a therapeutic target across a variety of clinical domains.

Treatment of Hypothalamic Obesity With GLP-1 Analogs

Introduction

Congenital and acquired damage to hypothalamic nuclei or neuronal circuits controlling satiety and energy expenditure results in hypothalamic obesity (HO). To date, successful weight loss and satiety has only been achieved in a limited number of affected patients across multiple drug trials. Glucagon-like peptide-1 (GLP-1) acts via central pathways that are independent from the hypothalamus to induce satiety. GLP-1 receptor agonists (GLP-1RAs) may provide an alternative approach to treating HO.

Methods

We performed a comprehensive search in Medline, Google Scholar, and clinical trials registries (ClinicalTrials.gov; clinicaltrialsregister.eur). This nonsystematic literature review was conducted to identify scientific papers published from January 2005 to February 2024 using the Pubmed and Embase databases. Key words used were GLP-1, GLP-1RA, hypothalamic obesity, suprasellar tumor, and craniopharyngioma.

Results

Our search identified 7 case studies, 5 case series, and 2 published clinical trials relating to the use of GLP-1RAs in HO. All case studies demonstrated weight loss and improved metabolic function. In contrast, results from case series were variable, with some showing no weight loss and others demonstrating moderate to significant weight loss and improved metabolic parameters. In the ECHO clinical trial, nearly half the subjects randomized to weekly exenatide showed reduced body mass index (BMI). Paradoxically, BMI reduction was greater in patients with more extensive hypothalamic injuries.

Conclusion

GLP-1RAs potentially offer a new approach to treating HO. There is a need to stratify patients who are more likely to respond. Further randomized controlled trials are required to determine their efficacy either in isolation or combined with other therapies.

Selective Colocalization of GHSR and GLP-1R in a Subset of Hypothalamic Neurons and Their Functional Interaction

The GH secretagogue receptor (GHSR) and the glucagon-like peptide-1 receptor (GLP-1R) are G protein-coupled receptors with critical, yet opposite, roles in regulating energy balance. Interestingly, these receptors are expressed in overlapping brain regions. However, the extent to which they target the same neurons and engage in molecular crosstalk remains unclear. To explore the potential colocalization of GHSR and GLP-1R in specific neurons, we performed detailed mapping of cells positive for both receptors using GHSR-eGFP reporter mice or wild-type mice infused with fluorescent ghrelin, alongside an anti-GLP-1R antibody. We found that GHSR+ and GLP-1R+ cells are largely segregated in the mouse brain. The highest overlap was observed in the hypothalamic arcuate nucleus, where 15% to 20% of GHSR+ cells were also GLP-1R+ cells. Additionally, we examined RNA-sequencing datasets from mouse and human brains to assess the fraction and distribution of neurons expressing both receptors, finding that double-positive Ghsr+/Glp1r+ cells are highly segregated, with a small subset of double-positive Ghsr+/Glp1r+ cells representing <10% of all Ghsr+ or Glp1r+ cells, primarily enriched in the hypothalamus. Furthermore, we conducted functional studies using patch-clamp recordings in a heterologous expression system to assess potential crosstalk in regulating presynaptic calcium channels. We provide the first evidence that liraglutide-evoked GLP-1R activity inhibits presynaptic channels, and that the presence of one GPCR attenuates the inhibitory effects of ligand-evoked activity mediated by the other on presynaptic calcium channels. In conclusion, while GHSR and GLP-1R can engage in molecular crosstalk, they are largely segregated across most neuronal types within the brain.

Glucagon-like Peptide 1 Receptor Agonists in Cardio-Oncology: Pathophysiology of Cardiometabolic Outcomes in Cancer Patients

Cancer patients, especially long cancer survivors, are exposed to several cardio-metabolic diseases, including diabetes, heart failure, and atherosclerosis, which increase their risk of cardiovascular mortality. Therapy with glucagon-like peptide 1 (GLP1) receptor agonists demonstrated several beneficial cardiovascular effects, including atherosclerosis and heart failure prevention. Cardiovascular outcome trials (CVOTs) suggest that GLP-1 RA could exert cardiorenal benefits and systemic anti-inflammatory effects in patients with type-2 diabetes through the activation of cAMP and PI3K/AkT pathways and the inhibition of NLRP-3 and MyD88. In this narrative review, we highlight the biochemical properties of GLP-1 RA through a deep analysis of the clinical and preclinical evidence of the primary prevention of cardiomyopathies. The overall picture of this review encourages the study of GLP-1 RA in cancer patients with type-2 diabetes, as a potential primary prevention strategy against heart failure and atherosclerosis.

The protective role of brown adipose tissue in cardiac cell damage after myocardial infarction and heart failure

Acute myocardial infarction (AMI) and related cardiovascular disease complications are the leading causes of mortality worldwide. Brown adipose tissue (BAT) is thermogenic and characterized by the uncoupling protein expression. Recent studies have found that in cardiovascular diseases, activated BAT can effectively improve the prognosis of AMI and concurrent heart failure through intercellular communication. However, a clear and systematic understanding of the myocardial protective mechanism of BAT after AMI is lacking, especially in the endocrine function of BAT. This review describes the effects of BAT on various cells in the heart after AMI. BAT plays a protective role on cardiac cells and fibroblasts during ischemia/reperfusion (I/R), myocardial remodeling, and myocardial fibrosis. This review also discusses the changes caused by BAT activation in different stages of heart failure. Finally, this review summarizes the treatment methods that target BAT to improve AMI. Further in-depth researches are still needed to clarify the underlying mechanism of the connection between BAT and different cells in cardiac tissue in order to identify potential therapeutic targets.

Mitochondrial Function and Dysfunction in White Adipocytes and Therapeutic Implications

For a long time, white adipocytes were thought to function as lipid storages due to the sizeable unilocular lipid droplet that occupies most of their space. However, recent discoveries have highlighted the critical role of white adipocytes in maintaining energy homeostasis and contributing to obesity and related metabolic diseases. These physiological and pathological functions depend heavily on the mitochondria that reside in white adipocytes. This article aims to provide an up-to-date overview of the recent research on the function and dysfunction of white adipocyte mitochondria. After briefly summarizing the fundamental aspects of mitochondrial biology, the article describes the protective role of functional mitochondria in white adipocyte and white adipose tissue health and various roles of dysfunctional mitochondria in unhealthy white adipocytes and obesity. Finally, the article emphasizes the importance of enhancing mitochondrial quantity and quality as a therapeutic avenue to correct mitochondrial dysfunction, promote white adipocyte browning, and ultimately improve obesity and its associated metabolic diseases. © 2024 American Physiological Society. Compr Physiol 14:5581-5640, 2024.

An insoluble cellulose nanofiber with robust expansion capacity protects against obesity

An imbalance between energy intake and energy expenditure predisposes obesity and its related metabolic diseases. Soluble dietary fiber has been shown to improve metabolic homeostasis mainly via microbiota reshaping. However, the application and metabolic effects of insoluble fiber are less understood. Herein, we employed nanotechnology to design citric acid-crosslinked carboxymethyl cellulose nanofibers (CL-CNF) with a robust capacity of expansion upon swelling. Supplementation with CL-CNF reduced food intake and delayed digestion rate in mice by occupying stomach. Besides, CL-CNF treatment mitigated diet-induced obesity and insulin resistance in mice with enhanced energy expenditure, as well as ameliorated inflammation in adipose tissue, intestine and liver and reduced hepatic steatosis, without any discernible signs of toxicity. Additionally, CL-CNF supplementation resulted in enrichment of probiotics such as Bifidobacterium and decreased in the relative abundances of deleterious microbiota expressing bile salt hydrolase, which led to increased levels of conjugated bile acids and inhibited intestinal FXR signaling to stimulate the release of GLP-1. Taken together, our findings demonstrate that CL-CNF administration protects mice from diet-induced obesity and metabolic dysfunction by reducing food intake, enhancing energy expenditure and remodeling gut microbiota, making it a potential therapeutic strategy against metabolic diseases.

GLP-1 programs the neurovascular landscape

Readily available nutrient-rich foods exploit our inherent drive to overconsume, creating an environment of overnutrition. This transformative setting has led to persistent health issues, such as obesity and metabolic syndrome. The development of glucagon-like peptide-1 receptor (GLP-1R) agonists reveals our ability to pharmacologically manage weight and address metabolic conditions. Obesity is directly linked to chronic low-grade inflammation, connecting our metabolic environment to neurodegenerative diseases. GLP-1R agonism in curbing obesity, achieved by impacting appetite and addressing associated metabolic defects, is revealing additional benefits extending beyond weight loss. Whether GLP-1R agonism directly impacts brain health or does so indirectly through improved metabolic health remains to be elucidated. In exploring the intricate connection between obesity and neurological conditions, recent literature suggests that GLP-1R agonism may have the capacity to shape the neurovascular landscape. Thus, GLP-1R agonism emerges as a promising strategy for addressing the complex interplay between metabolic health and cognitive well-being.

DACRA induces profound weight loss, satiety control, and increased mitochondrial respiratory capacity in adipose tissue

BACKGROUND AND OBJECTIVES

Dual amylin and calcitonin receptor agonists (DACRAs) are therapeutic candidates in the treatment of obesity with beneficial effects on weight loss superior to suppression of food intake. Hence, suggesting effects on energy expenditure by possibly targeting mitochondria in metabolically active tissue.

METHODS

Male rats with HFD-induced obesity received a DACRA, KBP-336, every third day for 8 weeks. Upon study end, mitochondrial respiratory capacity (MRC), - enzyme activity, - transcriptional factors, and -content were measured in perirenal (pAT) and inguinal adipose tissue. A pair-fed group was included to examine food intake-independent effects of KBP-336.

RESULTS

A vehicle-corrected weight loss (23.4 ± 2.8%) was achieved with KBP-336, which was not observed to the same extent with the food-restricted weight loss (12.4 ± 2.8%) (P < 0.001). Maximal coupled respiration supported by carbohydrate and lipid-linked substrates was increased after KBP-336 treatment independent of food intake in pAT (P < 0.01). Moreover, oligomycin-induced leak respiration and the activity of citrate synthase and β-hydroxyacetyl-CoA-dehydrogenase were increased with KBP-336 treatment (P < 0.05). These effects occurred without changes in mitochondrial content in pAT.

CONCLUSIONS

These findings demonstrate favorable effects of KBP-336 on MRC in adipose tissue, indicating an increased energy expenditure and capacity to utilize fatty acids. Thus, providing more mechanistic insight into the DACRA-induced weight loss.

Glucagon-like peptide-1 receptor agonists in neoplastic diseases

Glucagon-like peptide-1 receptor agonist (GLP-1RA), a novel hypoglycemic agent for the treatment of type 2 diabetes, has well-known effects such as lowering blood sugar, ameliorating inflammation, reducing weight, and lowering blood lipids. It has also been shown that it can influence the proliferation and survival of cells and has a certain effect on the prognosis of some neoplastic diseases. In this study, the potential effects of GLP-1RAs on the occurrence and development of tumors were reviewed to provide new ideas for the prevention and treatment of tumors in patients.

GLP-1R-positive neurons in the lateral septum mediate the anorectic and weight-lowering effects of liraglutide in mice

Liraglutide, a glucagon-like peptide-1 (GLP-1) analog, is approved for obesity treatment, but the specific neuronal sites that contribute to its therapeutic effects remain elusive. Here, we show that GLP-1 receptor-positive (GLP-1R-positive) neurons in the lateral septum (LSGLP-1R) play a critical role in mediating the anorectic and weight-loss effects of liraglutide. LSGLP-1R neurons were robustly activated by liraglutide, and chemogenetic activation of these neurons dramatically suppressed feeding. Targeted knockdown of GLP-1 receptors within the LS, but not in the hypothalamus, substantially attenuated liraglutide's ability to inhibit feeding and lower body weight. The activity of LSGLP-1R neurons rapidly decreased during naturalistic feeding episodes, while synaptic inactivation of LSGLP-1R neurons diminished the anorexic effects triggered by liraglutide. Together, these findings offer critical insights into the functional role of LSGLP-1R neurons in the physiological regulation of energy homeostasis and delineate their instrumental role in mediating the pharmacological efficacy of liraglutide.

Machine Learning-Based Plasma Metabolomics in Liraglutide-Treated Type 2 Diabetes Mellitus Patients and Diet-Induced Obese Mice

Liraglutide, a glucagon-like peptide-1 receptor agonist, is effective in the treatment of type 2 diabetes mellitus (T2DM) and obesity. Despite its benefits, including improved glycemic control and weight loss, the common metabolic changes induced by liraglutide and correlations between those in rodents and humans remain unknown. Here, we used advanced machine learning techniques to analyze the plasma metabolomic data in diet-induced obese (DIO) mice and patients with T2DM treated with liraglutide. Among the machine learning models, Support Vector Machine was the most suitable for DIO mice, and Gradient Boosting was the most suitable for patients with T2DM. Through the cross-evaluation of machine learning models, we found that liraglutide promotes metabolic shifts and interspecies correlations in these shifts between DIO mice and patients with T2DM. Our comparative analysis helped identify metabolic correlations influenced by liraglutide between humans and rodents and may guide future therapeutic strategies for T2DM and obesity.