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This study investigates the relationships between melanocortin-4 receptor (MC4R) rs17782313 gene polymorphisms, low-fat diet, aerobic exercise, and the reduction in blood lipid levels in individuals with obesity. A total of 240 adults living with obesity were enrolled to take part in a 12-week program that combined exercises with dietary interventions. Measurements taken included body weight, body mass index (BMI), plasma lipids, fasting insulin (FIN), and insulin resistance (Homeostasis Model Assessment, HOMA-IR). All participants underwent exercise intervention and genotyping. Our findings revealed significant interactions between genotype, sex, and diet in modulating lipid metabolism. Specifically, after the exercise intervention, the mean reduction in BMI in was: CC+CT with low-fat diet: -2.56 ± 1.98 kg/m The CC+CT genotype group, particularly males on a low-fat diet, showed robust improvements in TG, LDL-C, and insulin resistance markers. However, HDL-C responses were inconsistent across subgroups. Notably, males with the CC+CT allele exhibited the most pronounced benefits in LDL-C reduction and HOMA-IR improvement with a low-fat diet. Show less

A previous study of 200,000 exome-sequenced UK Biobank participants investigating the association between rare coding variants and BMI had implicated two genes, MC4R and PCSK1, at exome-wide significance. In addition, further 66 genes were significant with an uncorrected p value of <0.001. Exome sequence data have become available for further 270,000 participants, and weighted burden analyses to test for association with BMI were carried out in this sample for all the 68 genes highlighted by the previous study. Three novel genes, in addition to MC4R and PCSK1, were significant after correction for multiple testing: PTOV1, GALNT9, and ATP8B2. All five genes were exome-wide significant in the whole sample of 470,000 participants. Rare coding variants impairing gene function were associated with reduced BMI for ATP8B2 but increased BMI for the other genes, and for all genes, loss of function variants had larger effect sizes than nonsynonymous variants. The biological mechanisms whereby the novel genes might affect BMI are not clear, although impairment of ATP8B2 might possibly have an effect on insulin secretion. Functional studies might throw further light on how these genes are involved in regulation of body weight. Collectively, the identified variants are very rare and do not make a major contribution to variation in BMI in the population. This research has been conducted using the UK Biobank Resource. Show less

Obesity is a heritable disease, but its genetic basis is incompletely understood. Canine population history facilitates trait mapping. We performed a canine genome-wide association study for body condition score-a measure of obesity-in 241 Labrador retrievers. Using a cross-species approach, we showed that canine obesity genes are also associated with rare and common forms of obesity in humans. The lead canine association was within the gene DENN domain containing 1B ( Show less

With the advancement of genomic technologies, precision lifestyle interventions tailored to individual genetic backgrounds have emerged as a novel approach for preventing and managing chronic diseases such as obesity. Several randomized controlled trials (RCTs) targeting obese or overweight populations have found that individuals with different genotypes exhibit varying responses to the same lifestyle intervention (gene-lifestyle intervention interactions). To date, more than 20 genes, including Show less

Astrocytes are key regulators of neuroinflammation in multiple sclerosis (MS). Electroacupuncture (EA), a safe and cost-effective adjuvant therapy, has shown benefits in neurodegenerative diseases, but its astrocyte-related mechanisms remain unclear. Here, we demonstrated that EA at ST36 alleviated blood-brain barrier (BBB) disruption and neuroinflammation during the peak period of experimental autoimmune encephalomyelitis (EAE). Additionally, EA at ST36 upregulated the expression of α-melanocyte-stimulating hormone (α-MSH) and its receptor melanocortin-4 receptor (MC4R) in spinal astrocytes. Pharmacological studies showed that MC4R agonist RO27-3225 mimicked the therapeutic effects of EA, whereas MC4R antagonist TCMCB07 weakened EA-mediated BBB protection and neuroinflammation suppression. Moreover, astrocyte-specific silencing of MC4R via adeno-associated virus (AAV) weakened EA-mediated BBB protection and neuroinflammation suppression. RNA-sequencing (RNA-seq) and western blot (WB) revealed that EA exerts neuroprotective effects by activating MC4R to inhibit MAPK and NF-κB signaling pathways. Moreover, in MC4R-overexpressing astrocytes, α-MSH and RO27-3225 reduced inflammation responses, while TCMCB07 reversed the effects by MAPK/NF-κB signaling pathways. Collectively, our findings identify astrocytic MC4R as a critical mediator of EA-driven neuroprotection by suppressing MAPK/NF-κB signaling, providing mechanistic insight and a promising therapeutic target for EAE and other neuroinflammatory disorders. Show less

The melanocortin-4 receptor (MC4R) agonists have emerged as potential treatments for obesity, particularly in patients with rare genetic syndromes. However, their overall effects on obesity and cardiometabolic risk factors remain uncertain. To systematically evaluate the efficacy of MC4R agonists on weight-related outcomes and cardiometabolic risk factors. We conducted this study following PRISMA 2020 guidelines. Eligible studies included clinical trials ((RCTs and single-arm trials) of the effects of MC4R agonist drugs on anthropometric factors and cardiovascular risk factors. Random model effects meta-analyses were performed for this meta-analysis, with heterogeneity and small-study effects explored through sensitivity and publication bias analyses. A total of 12 studies were included. Treatment with MC4R agonists significantly reduced body weight compared with placebo in RCTs (WMD − 5.07 kg; 95% CI − 8.13 to − 2.02), with even larger reductions in single-arm studies (–11.23%; 95% CI − 15.43 to − 7.04). MC4R agonists also lowered BMI by − 13.67% (95% CI − 17.21 to − 10.12), waist circumference by − 11.75 cm, BMI Z-score by − 0.98, and hunger scores by − 3.38. These agents reduced triglyceride levels by − 35.53 mg/dL and LDL-C levels by − 9.14 mg/dL, while HDL-C levels showed a nonsignificant increase of + 2.37 mg/dL. Systolic blood pressure declined by − 4.38 mmHg, while diastolic pressure showed no meaningful change. MC4R agonists produce clinically meaningful weight reduction and improvements in several cardiometabolic risk factors. These findings support MC4R agonists as a promising therapy for genetic forms of obesity, while their role in nonspecific obesity requires confirmation in large, long-term randomized trials. The online version contains supplementary material available at 10.1186/s13098-025-02071-2. Show less

Central melanocortin signaling plays a critical role in maintaining energy homeostasis by regulating energy intake and expenditure, with impairment of this system closely related to metabolic diseases such as obesity. Among melanocortin receptor subtypes, melanocortin receptor 4 (MC4R) is the primary mediator of these effects within the central nervous system. Accumulating evidence suggests that MC4R contributes to stress-induced disruptions in feeding behavior and energy homeostasis. However, the precise neural mechanisms by which stress alters MC4R activity remain incompletely understood. In this study, we compared brain-wide c-Fos expression patterns induced by two distinct stress paradigms: lipopolysaccharide (LPS)-induced inflammatory stress and restraint stress in male mice, and further examined the involvement of MC4R-expressing (MC4R Show less

Hypothalamic obesity (HO) is a disabling disease caused by central nervous system (CNS) damage due to neurosurgery, trauma, or tumors, especially in hypothalamus. The pathological mechanism of its neural circuits is still unclear, and there is currently no corresponding drug due to the complex etiology. G protein-coupled receptors (GPCRs) regulate neural function in many CNS diseases. Among them, melanocortin 4 receptor (MC4R) regulate metabolism and appetite in the hypothalamus. Setmelanotide, an MC4R agonist, has demonstrated anti-obesity effects in genetic forms of obesity; however, its efficacy and mechanisms in HO remain unexplored. This study explored the potential of treating HO by setmelanotide-targeted activation of MC4R in the paraventricular nucleus (PVN). We established a rat hypothalamic injury model to replicate human HO symptoms, such as hyperphagia (50% increase in food intake), elevated Lee index, and more than 25% weight gain. Immunofluorescence and immunoblot analysis showed that HO disrupted the PVN neuropeptides, leading to the inhibition of MC4R via calmodulin-dependent protein kinase kinase 2 (CaMKK2) and AMP-activated protein kinase (AMPK) signaling. Crucially, administration of setmelanotide restored CaMKK2/AMPK activity, reactivated MC4R neurons, and normalized appetite and feeding behavior during fasting-refeeding and the long-term treatment of obese rats (60% reduction in food intake), ultimately reversing obesity (23% weight loss). These findings underscore the critical role of MC4R dysfunction in hypothalamic injury and highlight the strategies to pharmacologically activate MC4R via CaMKK2/AMPK signaling to restore metabolic homeostasis, proposing a translatable therapeutic agent to manage obesity caused by CNS injury. Show less

Maternal consumption of monosaccharides during pregnancy and lactation can program long-term metabolic and neurobehavioral outcomes in offspring. The melanocortin-4 receptor (MC4R) is a key regulator of metabolism and behavior. However, the impact of maternal monosaccharide diets on MC4R signaling within mesocorticolimbic regions remains unclear. In this study, we investigated the effects of maternal glucose (GLU) and fructose (FRU) diets on metabolic, molecular, and neurochemical outcomes in offspring. Adolescent and young adult male and female Wistar rat offspring, following maternal GLU and FRU exposure during pregnancy and lactation, underwent sucrose preference testing, intraperitoneal glucose tolerance tests, and serum lipid profiling. In addition, the gene expression of The maternal GLU diet reduced total calorie intake during lactation, while the FRU diet increased the dams’ caloric intake from sugar during both pregnancy and lactation. In the offspring, a maternal FRU diet increased sucrose consumption in young adult males and dysregulated glucose homeostasis in both adolescent and young adult males. Maternal monosaccharide diets also influenced serum lipid profiles and increased the body weights of their offspring. At the molecular level, region-, sex-, and age-specific changes in gene expression were observed, particularly the upregulation of These findings suggest that maternal monosaccharide diets induce persistent alterations in the metabolic profiles of offspring and MC4R signaling, potentially contributing to the development of programmed metabolic and behavioral outcomes. Not applicable. The online version contains supplementary material available at 10.1007/s43440-025-00785-8. Show less

Osteoarthritis (OA) is a common progressive joint disorder marked by synovial inflammation, cartilage degeneration, the formation of osteophytes, though its underlying molecular mechanisms remain unclear. This study integrated bioinformatics and experimental validation to identify key genes in OA synovium and their association with immune infiltration. Analysis of the GSE82107 dataset (10 OA, 7 controls) revealed 909 differentially expressed genes (525 upregulated, 384 downregulated). WGCNA identified the "midnightblue" module, and its intersection with DEGs yielded 122 genes enriched in cytokine-cytokine receptor interaction, JAK-STAT signaling, and autophagy pathways. Protein-protein interaction analysis highlighted FLT3LG, MC4R, CXCL10, CARTPT, and LHX2 as core genes (AUC 0.743-0.871). Immune infiltration analysis showed elevated M0 macrophages in OA, with CXCL10 showing a strong positive correlation with M1 macrophage infiltration (r = 0.74), and MC4R correlating with the presence of follicular helper T cells (r = 0.85). In vitro, OA-derived fibroblast-like synoviocytes exhibited CXCL10 upregulation, MC4R downregulation, and increased IL-6, IL-8, and TNF-α secretion, which were markedly reduced by CXCL10 knockdown or MC4R overexpression. Synovial tissue assays confirmed these expression patterns. CXCL10 and MC4R may represent promising diagnostic markers and therapeutic targets, offering new insights into OA immunopathogenesis and precision intervention. Show less

This study identified genomic variants and potential candidate genes associated with 11 primal cut traits (back fat, belly fat, total fat, loin fat, ham fat, picnic fat, butt fat, loin intramuscular fat content, ham side fat, shoulder dorsal fat, and belly side fat thicknesses) in Canadian commercial crossbred pigs. Genome-wide association studies using whole genome sequencing data were conducted using genotyping data from 1118 commercial crossbred pigs. This analysis revealed multiple QTLs across chromosomes SSC1, 2, 3, 6, 7, 9, 14, 15, and 17, associated with fat traits. Notably, an SNP at position 160,230,075 bp on SSC1 was significantly associated with multiple fat traits, including belly fat, butt fat, ham fat, loin fat, picnic fat, and side fat. Common genes in windows associated with multiple traits, such as Show less

Obesity is a global health challenge characterized by significant heterogeneity in causes and treatment responses, complicating sustainable management. This narrative review explores the genomic architecture of obesity and its implications for personalized interventions, focusing on how genetic variations influence key biological pathways and treatment outcomes. A comprehensive literature search, guided by the authors' expertise, was conducted to identify key publications on the genomics of obesity and personalized approaches. The selection of articles prioritized those that provided direct insights into the genomic basis of obesity and its potential for informing tailored strategies. Genomic studies reveal both monogenic and polygenic influences on obesity, identifying numerous susceptibility loci. Genome-wide association studies (GWASs) have linked common variants in genes like Show less

The preoptic area (POA) is a well-established regulator of body temperature, but its role in feeding behavior remains underexplored. Our study identifies leptin receptor (Lepr)-expressing neurons in the POA (POA Show less

Many membrane proteins, including G protein-coupled receptors (GPCRs), are susceptible to denaturation when extracted from their native membrane by detergents. Therefore, alternative methods have been developed, including amphiphilic copolymers that enable the direct extraction of functional membrane proteins along with their surrounding lipids. Among these amphiphilic copolymers, styrene/maleic acid (SMA) and diisobutylene/maleic acid (DIBMA) polymers have been extensively studied. Despite their many benefits, SMA and DIBMA polymers also have considerable drawbacks limiting their applications. Herein, we describe a series of new amphiphilic copolymers derived from DIBMA via partial amidation of the carboxylate pendant groups with various biocompatible amines. We characterize the new polymer's nanodisc-forming properties and ability to extract the melanocortin 4 receptor (MC Show less

The central melanocortin system, composed of peptides derived from pro-opiomelanocortin (POMC) such as the melanocyte-stimulating hormones (α-, β-, γ-MSH) and melanocortin 4 receptors (MC4R), along with the agouti-related protein (AgRP), plays a pivotal role in controlling energy balance. To elucidate the dynamic role of α-MSH release in regulating appetite, specific, sensitive, and spatiotemporally resolved genetic sensors are required. The melanocortin 1 receptor (MC1R) scaffold was leveraged for its robust plasma membrane expression, high affinity for melanocortins and low affinity for AgRP to design a α-MSH selective sensor for in vivo use. This was achieved by integrating circularly permuted green fluorescent protein (cpGFP) into the receptor, which we named Fluorescence Amplified Receptor sensor for Melanocortin (FLARE The FLARE FLARE Show less

Non-olfactory G-protein-coupled receptors (GPCRs) regulate vital physiological functions and are targets for ∼34% of US Food and Drug Administration (FDA)-approved drugs. While small-molecule-activated GPCRs are well studied, there is growing interest in peptide GPCRs, particularly the melanocortin-4 receptor (MC4R), a key regulator of energy balance and appetite. Activation of MC4R by β-melanocyte-stimulating hormone (β-MSH) reduces food intake, and pathway dysfunction leads to obesity. However, current methods to study GPCR-peptide interactions are resource intensive and low throughput. To address this, we developed a high-throughput cell surface peptide display platform with a β-arrestin-based MC4R reporter to screen over 2,000 β-MSH point mutants. This approach identified peptide variants that significantly impact MC4R activation, including a novel D5H mutant with enhanced receptor activation. Our results demonstrate a scalable method to directly link GPCR activation to peptide variants, offering insights for therapeutic peptide design. Show less

Hypothalamic pro-opiomelanocortin (POMC) neurons are classically viewed as mediators of satiety, acting in response to metabolic and hormonal cues and in opposition to Agouti-related protein (AgRP) neurons to maintain energy balance. This model, centered on the appetite-suppressant effects of the POMC-derived neuropeptide α-melanocyte-stimulating hormone (α-MSH) through its activation of melanocortin-4 receptors (MC4R), has shaped our understanding of feeding and body weight regulation for decades. However, recent discoveries have challenged and expanded this traditional view, revealing that POMC neurons are not a uniform population dedicated solely to satiety control. Single-cell transcriptomic analyses have revealed striking molecular heterogeneity, reflected in distinct anatomical distributions, receptor expression profiles, electrophysiological properties, and projection patterns - all supporting the idea of functional specialization within this neuronal population. In this review, we propose a conceptual framework that integrates POMC neuronal heterogeneity with the regulation of appetite, metabolic physiology, and behavior beyond feeding. We highlight emerging evidence showing that discrete POMC neuronal subpopulations respond to specific combinations of interoceptive and environmental cues to orchestrate diverse adaptive responses. This perspective underscores the developmental plasticity and functional versatility of POMC neurons, offering new insights into the mechanisms of obesity and potentially paving the way for novel targeted therapeutic strategies. Show less

Melanocortin receptors (MCRs) are responsible for various functions ranging from skin pigmentation, regulation of appetite, stress response and cognition, steroid synthesis, and energy balance to cellular regeneration and immunomodulation. The genetic polymorphism with tissue distribution ranging from the brain, limbic system, and adrenal cortex to neutrophils, monocytes, and macrophages is evident in MCRs. The mutations in MC1R, MC2R, MC3R, and MC4R genes are associated with risk of melanoma, familial glucocorticoid deficiency, obesity, and type 2 diabetes mellitus, respectively. Meanwhile, MC1R, MC2R, and MC5R genes are involved in the risk of major depressive disorder. Melanocortin receptors are involved in different inflammatory disorders, i.e., atopic dermatitis, autoimmune uveitis, sarcoidosis, respiratory diseases, multiple sclerosis, scleroderma, inflammatory bowel disease, amyotrophic lateral sclerosis, Alzheimer's disease, arthritis, and reperfusion injury. Several newer therapeutic agents related to MCRs have numerous advantages over the current anti-inflammatory drugs, demonstrating therapeutic relevance. Among them, α-MSH analogs play a role in atopic dermatitis and scleroderma, and MC1R agonist Dersimelagon has shown effectiveness in systemic sclerosis. The FDA has recently approved the repository corticotropin injection (RCI) to treat sarcoidosis. The FDA has also approved various melanocortin agonists, i.e., Bremelanotide, Afamelanotide, and Setmelanotide, for the treatment of hypoactive sexual desire disorder, Erythropoietic protoporphyria, and obesity, due to pro-opiomelanocortin and leptin receptor deficiency, respectively. Therefore, this review aims to summarize the function and genetic polymorphism of melanocortin receptors, regulatory pathways involving MCRs, and the existing evidence of the prime effect of MCRs on inflammatory responses via different mechanisms and their potential therapeutic use in inflammatory diseases. Show less

Studies in mammal models show that reduced sleep is associated with increased food intake. Zebrafish (Danio rerio) is emerging as a promising model for studying sleep and feeding behaviour due to its similarities with mammals. Our goal was to investigate whether sleep restriction increases food intake in zebrafish, its potential effects on central regulation of feeding, and whether effects are similar in both sexes. Individually housed male and female adult zebrafish were exposed to nighttime (ND) or daytime (DD) vibrations and compared to a control group without vibration (n = 30 males and n = 27 females). ND, but not DD, reduced sleep during the disturbance period, with males showing a significant effect and females exhibiting an altered sleep pattern without a statistically significant reduction. ND also significantly increased food intake in males, as measured by daily milligrammes and number of pellets consumed. In contrast, ND females exhibited a decrease in the time spent feeding, suggesting a sex-specific response to sleep disruption. The whole brain expression of neuropeptide Y (npy), proopiomelanocortin (pomc), and its receptor melanocortin-4 (mc4r) were analysed by RT-qPCR. Males from ND exhibited significantly reduced pomc mRNA levels. Grouped-housed (three male and two female) zebrafish exposed to ND also exhibited increased food intake. In conclusion, sleep restriction affected food intake behaviour and the central regulation in zebrafish, with distinct sex-specific effects. Show less

Metabolic diseases, like type 2 diabetes mellitus and obesity, show a growing public health concern in Sri Lanka. Genetic predisposition and diet contribute to metabolic disease risk, but there are limited investigations into the impact of gene-diet interactions on metabolic disease risk in the Sri Lankan population. In this study, we examined whether a metabolic genetic risk score (GRS), constructed from 10 single nucleotide polymorphisms (SNPs), interacts with dietary factors to influence metabolic health indicators in Sri Lankan adults. This cross-sectional study included 105 generally healthy adults aged 25-50 years from the GOOD (Genetics of Obesity and Diabetes) study. Anthropometric, biochemical, and dietary data using food frequency questionnaires were collected using validated methods. Genotyping was performed using the KASP A statistically significant interaction was identified between the 10-SNP metabolic GRS and polyunsaturated fatty acid (PUFA) intake on waist circumference (P This study provides novel insights to understand gene-diet interactions affecting metabolic traits in Sri Lankans. The findings suggest that higher PUFA intake may mitigate genetic susceptibility to central obesity, highlighting the importance of personalized dietary recommendations for metabolic disease prevention. Further studies in larger cohorts are warranted to confirm this finding. Show less

Adamantinomatous craniopharyngioma (ACP) is a histologically benign but clinically aggressive tumor arising from Rathke's pouch remnants, which is molecularly distinct from the other subtype, papillary craniopharyngioma (PCP). Despite advancements in surgery and radiotherapy, treatment outcomes remain unsatisfactory due to the tumor's invasiveness and resistance to conventional therapies. This review systematically examines the molecular pathogenesis of ACP and evaluates current and emerging therapeutic strategies to improve clinical management. ACP is driven by CTNNB1 mutations and dysregulated Wnt/β-catenin signaling, alongside inflammatory and senescence-associated pathways. Current pharmacological approaches, including interferon-α, IL-6 inhibitors (e.g., tocilizumab), and intracystic agents (e.g., bleomycin), exhibit limited efficacy. Promising emerging therapies target the angiogenesis (e.g., bevacizumab) and MAPK/ERK pathway, which is activated by somatic BRAF V600E mutations in PCP, has been successfully targeted with BRAF/MEK inhibitors, demonstrating significant efficacy in the majority of treated PCP patients. whereas immune checkpoint inhibitors and SHH pathway modulators face significant challenges. Additionally, ACP-related endocrine dysfunction and hypothalamic obesity require tailored interventions, such as GLP-1 receptor agonists and MC4R-targeted therapies. Precision medicine, informed by molecular subtyping and multi-omics data, holds transformative potential for ACP treatment. Future strategies should focus on combinatorial therapies to address tumor heterogeneity, microenvironment modulation, and senolytic approaches. Collaborative multidisciplinary efforts are crucial to translating these insights into clinical practice, ultimately enhancing patient outcomes and quality of life. Show less

The melanocortin-4 receptor is a G protein-coupled receptor and a key regulator of appetite and metabolism. It can interact with the melanocortin-receptor accessory protein 2, a single transmembrane helix protein known to interact with several different G protein-coupled receptors. However, the consequences of this interaction are not completely understood. Here we report that co-expression of melanocortin-receptor accessory protein 2 has multiple effects on the melanocortin-4 receptor: it enhances G protein-mediated signaling and simultaneously impairs β-arrestin2 recruitment and, consequently, internalization. In addition, co-expression of melanocortin-receptor accessory protein 2 leads to an increased number of monomers of melanocortin-4 receptor by disrupting receptor oligomers. A structural homology model of the active state melanocortin-4 receptor - melanocortin-receptor accessory protein 2 - Gα Show less

Early-onset severe obesity is rare and largely treatment-resistant to standard measures. Etiologies include syndromic disorders (Prader-Willi, Bardet-Biedl and Alström syndromes), monogenic defects of appetite-regulating pathways - most significantly melanocortin-4-receptor (MC4R) deficiency, but also leptin receptor (LEPR), pro-opiomelanocortin (POMC), and secondary hypothalamic injury, most commonly craniopharyngiomas. Most childhood obesity, however, is polygenic, arising from interactions of environmental and genetic factors. In many patients, no clear etiology is identified. Treatment remains challenging, particularly if hyperphagia and reduced satiety are predominant presenting features. We describe the case of a 19-year-old male with a history of autism spectrum disorder, attention-deficit hyperactivity disorder (ADHD), type 2 diabetes mellitus (T2DM) and morbid obesity, who showed a clinically significant response to tirzepatide therapy following failed conventional interventions. This case highlights the potential role of dual incretin therapy in adolescents with severe early-onset obesity and hyperphagia, even in the absence (based on present knowledge) of identifiable hypothalamic or genetic pathology. Show less

Leptin, a key adipokine regulating energy homeostasis, has been extensively studied for its potential in the management of obesity. However, its therapeutic efficacy is often limited due to leptin resistance. This review synthesizes animal and clinical evidence on leptin's role in obesity, focusing on models such as genetically deficient mice (e.g., ob/ob, db/db), diet-induced obesity mice, and clinical conditions such as congenital leptin deficiency (CLD), leptin receptor deficiency (LRD), lipodystrophy, and common obesity. The mechanisms underlying leptin resistance are summarized, including hyperleptinemia, impaired JAK2-STAT3 signaling, reduced blood-brain barrier permeability, defective autophagy, endoplasmic reticulum stress, inflammation, decreased leptin receptor expression, leptin signaling pathway dysfunction, increased mTOR activity, and peripheral leptin resistance. Due to these leptin receptor and/or post-receptor signaling pathway defects, leptin or its analogs usually fail to produce the expected weight-loss effect in individuals with overweight or obesity, although they remain highly effective in individuals with CLD and lipodystrophy, as well as in ob/ob mice. Alternative strategies, such as melanocortin-4 receptor (MC4R) agonists (e.g., setmelanotide) for LRD treatment, are very promising. Future directions include enhancing leptin sensitization, combining leptin with other drugs, and exploring partial leptin reduction to mitigate compensatory responses during weight loss. The review emphasizes the complexity of leptin resistance and the necessity of targeted approaches in obesity therapy. Show less

Obesity causes dyslipidemia and is a major risk factor for cardiovascular disease. However, the mechanisms coupling weight gain and lipid metabolism are poorly understood. Brain melanocortin 4 receptors (MC4Rs) regulate body weight and lipid metabolism in mice, but the relevance of these findings to humans is unclear. Here we investigated lipid levels in men and women with obesity due to MC4R deficiency. Among 7,719 people from the Genetics of Obesity Study cohort, we identified 316 probands and 144 adult family members with loss-of-function (LoF) MC4R mutations. Adults with MC4R deficiency had lower levels of total and low-density lipoprotein (LDL)-cholesterol and triglycerides than 336,728 controls from the UK Biobank, after adjusting for adiposity. Carriers of LoF MC4R variants within the UK Biobank had lower lipid levels and a lower risk of cardiovascular disease, after accounting for body weight, compared to noncarriers. After a high-fat meal, the postprandial rise in triglyceride-rich lipoproteins and metabolomic markers of fatty acid oxidation were reduced in people with MC4R deficiency compared to controls, changes that favor triglyceride storage in adipose tissue. We concluded that central MC4Rs regulate lipid metabolism and cardiovascular disease risk in humans, highlighting potential therapeutic approaches for cardiovascular risk reduction. Show less

Food addiction (FA) has gained more scientific attention but needs deeper understanding. Data indicates that the central melanocortin (MC) system through the MC4 receptor (MC4R) and its polymorphisms play a crucial role in the regulation of eating behaviour and in the motivation for the rewarding properties of food potentially leading to obesity. This may also contribute to the emergence of altered reward-related behaviors such as FA. The study aims to evaluate the genetic contribution of rs17782313, rs12970134, rs10871777, rs6567160, rs17700144 MC4R polymorphisms to the development of FA and to assess the association between these MC4R variations and clinical features. Eating (EDE-Q, BES, NEQ, GQ) and general psychopathology (BDI-II, STAI-S, DERS) were evaluated in patients with obesity with and without FA. Y-FAS 2.0 was used to assess FA. A blood sample was collected from all patients for the genotyping of MC4R polymorphisms. All the polymorphisms were equally distributed between groups except for rs17782313. A direct association between rs17782313 with FA was evident. Patients with FA and with C allele showed higher risk of FA compared to group without FA. There was a significant effect of rs17782313 on psychopathological variables in patients with FA. Allele C carriers exhibited higher anxiety and depression than T carriers. The rs17782313 of the MC4R showed an association with FA. A significant direct influence of C allele on anxiety and depression emerged in the group with FA but not in patients without FA. Show less

Obesity is a global health challenge marked by substantial inter-individual differences in responses to dietary and lifestyle interventions. Traditional weight loss strategies often overlook critical biological variations in genetics, metabolic profiles, and gut microbiota composition, contributing to poor adherence and variable outcomes. Our primary aim is to identify key biological and behavioral effectors relevant to precision medicine for weight control, with a particular focus on nutrition, while also discussing their current and potential integration into digital health platforms. Thus, this review aligns more closely with the identification of influential factors within precision medicine (e.g., genetic, metabolic, and microbiome factors) but also explores how these factors are currently integrated into digital health tools. We synthesize recent advances in nutrigenomics, nutritional metabolomics, and microbiome-informed nutrition, highlighting how tailored dietary strategies-such as high-protein, low-glycemic, polyphenol-enriched, and fiber-based diets-can be aligned with specific genetic variants (e.g., FTO and MC4R), metabolic phenotypes (e.g., insulin resistance), and gut microbiota profiles (e.g., Show less

The magnitude of weight reduction in the SURMOUNT-1 trial of the dual GLP-1 and GIP receptor agonist tirzepatide suggests that this treatment may be particularly effective in addressing the treatment needs of people with severe obesity (body mass index >40 kg m Show less