📋 Browse Articles

Among more than 300 candidate genes for obesity, A total of 231 healthy adults aged 19-64 years were recruited between March and May 2024. Anthropometric and clinical measurements, genotyping, dietary intake, and questionnaires on socioeconomic status, family history, and lifestyle behaviors were obtained. Associations between genotypes and obesity-related phenotypes were evaluated using ANOVA and ANCOVA, multivariable-adjusted models and multicollinearity analysis-based stepwise regression. In Koreans, MAFs for These findings support the relevance of Show less

Genetic factors are key determinants in the pathophysiology of obesity, regulating energy homeostasis. Monogenic non-syndromic obesity accounts for 2-3% of obesity in both children and adults and is most often attributable to mutations in genes encoding components of the leptin-melanocortin pathway. Genetic testing is indicated in children with severe obesity before age 5, hyperphagia, a family history of obesity, and neurodevelopmental delay or organ dysfunction. Mutations associated with monogenic obesity follow autosomal recessive ( Show less

Endoplasmic reticulum (ER) stress plays a significant role in chronic pain, but its potential involvement in chronic itch remains largely unexplored and poorly understood. In the current study, we investigated whether ER stress signaling in keratinocytes contributes to the pathogenesis of chronic itch. Our behavioral tests showed that the ER stress inhibitor 4-PBA attenuated itch-related behaviors in both acute and chronic itching mouse models, and reduced compound 48/80 and serotonin-induced activity of dorsal root ganglion (DRG) neurons. qPCR and western blotting revealed that the ER stress-related proteins and Lipocalin-2 (LCN2) were significantly elevated in the affected skin under chronic itch conditions and in cultured keratinocyte HaCaT cells and mice skin keratinocytes. The ELISA test showed that the level of LCN2 increased significantly in plasma but not in DRG tissue, from both acetone-ether-water (AEW) induced dry skin and imiquimod (IMQ) induced psoriasis model mice. Current clamp recording demonstrated that LCN2 induced hyperexcitability in dorsal root ganglia neurons, which could be abolished by HS024, the inhibitor of melanocortin receptor 4 (MC4R). In addition, pharmacological inhibition of transient receptor potential vanilloid 1 (TRPV1) or TRPV1 knockout blocked LCN2-induced hyperexcitability in DRG neurons. In conclusion, this study demonstrated that keratinocyte ER stress is involved in chronic itch genesis by releasing LCN2, which sensitized primary sensory neurons via TRPV1. These findings suggested that inhibition of ER stress in keratinocytes could be a promising therapeutic strategy for treating chronic itch. Show less

Western diet (WD) fed Melanocortin 4 receptor-knockout (MC4R-KO) mice develop a phenotype resembling human metabolic dysfunction-associated steatohepatitis (MASH). Despite its clinical relevance, the role of the gut–liver axis in MASH pathogenesis remains unclear. We investigated the gut-liver axis through microbiomic and metabolomic analyses of WD-fed MC4R-KO mice, and we examined their association with MASH pathology. We performed an integrated microbiome and metabolome analysis of the liver, small intestinal contents, large intestinal contents, and plasma of wild-type (WT) and MC4R-KO mice fed either a normal diet or WD. Markers of hepatic inflammation, fibrosis, and steatosis measured in this study were used to assess MASH severity and to correlate microbiome and metabolite alterations. WD-fed MC4R-KO mice exhibited significant hepatic steatosis, inflammation, and fibrosis. The abundance of certain microbiota, including Muribaculaceae and The observed gut microbial and metabolic alterations, particularly bile acid and lipid metabolism dysregulation, offer insights into potential therapeutic targets aimed at modulating the gut–liver axis to treat or prevent MASH. The online version contains supplementary material available at 10.1186/s13099-026-00813-9. Show less

The large-scale development of pig farming has introduced significant stressors that negatively affect pigs' mental health, behavior, and production efficiency. The hippocampus, crucial for cognition and stress response regulation, plays a central role in these processes. However, the regulatory mechanisms underlying hippocampal function across pig breeds with different domestication statuses and their implications for behavior and breeding strategies remain unclear. We performed single-nucleus RNA sequencing (snRNA-seq) on hippocampal tissues from 22,342 cells across three pig breeds: Asian wild boar, Jinhua, and Duroc, representing different domestication statuses. We identified six major hippocampal cell types and annotated 108 breed-specific transcription factors, including GATA2, SPI1, and EBF1. Additionally, we characterized 83 co-expression modules and 50 significant ligand-receptor pairs, such as TGFβ, WNT, and SPP1, revealing complex intercellular communication networks. Oligodendrocyte expression patterns were conserved across all breeds. We identified 194 candidate genes linked to stress resilience, mental health, and feeding behavior, including MC4R, RYR2, PDE10A, and ABCG2. Alzheimer's disease-related gene enrichment was lower in Duroc pigs, consistent with reduced APOE expression. We also developed the Pig Hippocampus Single-cell Atlas (PHiSA, http://alphaindex.zju.edu.cn:8503/ ), an open-access database allowing breed-specific hippocampal analyses and validation of gene expression at the single-nucleus level. This study offers insights into hippocampal function regulation in pigs, focusing on stress resilience, behavior, and productivity. It highlights conserved and breed-specific molecular features of hippocampal cell types and their roles in adaptability and mental health. By integrating single-nucleus data, the research suggests that genetic strategies could be used to improve animal welfare, stress management, and production efficiency in pig breeding programs. Show less

Metabolic side effects represent a major long-term concern in antipsychotic (AP)-treated early psychosis. We evaluated the weight gain and changes in related metabolic parameters in patients followed up for 12 months. We also explored DNA methylation of four genes associated with weight gain (ADRA2A, INSIG2, LEP, MC4R). We included patients aged 15-64 years followed in the Ribeirão Preto Early Intervention in Psychosis Program from two different cohorts (Clinical sample, n = 147; Epigenetic sample, n = 59). DNA methylation was analysed by pyrosequencing only at baseline, after several weeks of AP exposure. In both cohorts, 40% of patients initially received second-generation antipsychotics (SGAs), increasing to over 70% after one year. Clinical sample: At follow-up, patients exhibited significant increases in body mass index (p < 0.001), triglycerides (p < 0.001), HDL-c (p = 0.001) and LDL-c (p < 0.001). Patients predominantly on SGAs during the 12 months had almost three times higher chance of weight gain than those using haloperidol. Other factors associated with weight gain included non-white skin colour (OR = 2.6), fewer years of schooling (OR = 2.5) and a weight gain of at least 7% at three months (OR = 3.1). Epigenetic sample: Patients receiving SGA treatment (median = 23.4 weeks) at baseline showed hypermethylation within the MC4R promoter region in relation to patients using haloperidol (median = 18.6 weeks). No changes in the baseline methylation of other genes related to weight gain or AP drugs were observed longitudinally. MC4R promoter hypermethylation in SGA-treated patients suggests drug-induced metabolic alterations and a potential role of MC4R as a biomarker for predicting AP-related metabolic risk. 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

Genetic factors are thought to play an important role in antipsychotic-induced weight gain (AIWG). This study conducted a meta-analysis of current research of the pharmacogenetic associations of adult AIWG. The analysis included papers providing comparisons of weight gain across at least two allele combinations for at least one single nucleotide polymorphism (SNP). Inclusion criteria were, patients 18 years of age or older and had received a diagnosis of severe mental illness, for which antipsychotic medication was prescribed. The association with AIWG needed to be replicated across at least two papers reporting separate sample sets. Two hundred twenty-three papers were assessed for eligibility. Of the 223 papers, 148 were excluded, leaving 75 studies to be included. Six SNPs in six different genes were identified as having significant associations ( The study identified six SNPs that predispose adult individuals to AIWG, with Show less

Melanocortin 4 receptor (MC4R) is a G-protein-coupled receptor expressed in the hypothalamus, playing a key role in regulating feeding behavior and energy homeostasis. MC4R is integral to the POMC-MC4R and leptin-MC4R pathways, which control food intake and body weight. Mutations in the POMC gene lead to severe early-onset obesity and increased food consumption. Recently, glucagon-like peptide-1 (GLP-1) analogs, including semaglutide, tirzepatide, and retatrutide, have been explored as potential anti-obesity therapies. This study aimed to assess and compare the efficacy of these GLP-1 analogs in MC4R knockout (KO) mice, which are deficient in the POMC-MC4R pathway. GLP-1 analogs were administered for 21 days to MC4R KO mice and compared their efficacy. The percentage of body weight reduction was 19.7 ± 4.1% for semaglutide, 31.6 ± 7.6% for tirzepatide, and 24.1 ± 5.8% for retatrutide. Body composition analysis, including fat and lean mass, was performed using the Echo-MRI system, revealing significant suppression of both fat and lean mass by all three GLP-1 analogs. Furthermore, GLP-1 analogs improved plasma insulin levels, HOMA-IR, cholesterol levels, and markers of liver damage (AST and ALT), as well as reduced liver hypertrophy. While GLP-1 analogs suppressed genes related to fatty acid synthesis, they had no significant effect on inflammation-related gene expressions. Additionally, GLP-1 analogs reduced energy expenditure, with only tirzepatide showing a significant decrease in the respiratory quotient (RQ) in MC4R KO mice. Our findings demonstrate that all three GLP-1 analogs, semaglutide, tirzepatide, and retatrutide, exhibit significant anti-obesity effects in MC4R KO mice. These results suggest that GLP-1 analogs may provide an effective treatment option for patients with MC4R-POMC pathway deficiencies. Moreover, the efficacy of these drugs in MC4R KO mice aligns with clinical studies, indicating that MC4R KO mice serve as a reliable animal model for obesity research. Show less

The melanocortin-2 receptor accessory protein (MRAP) family interacts with and regulates the signaling of diverse G protein-coupled receptors (GPCRs). MRAP2 modifies the signaling of three distinct GPCRs, melanocortin-4 receptor (MC4R), MC3R, and ghrelin receptor (GHSR), all essential for appetite regulation. The nature of MRAP2/GPCR complexes and whether there are shared mechanisms for complex assembly, critical structural regions, or consistent effects on receptor signaling remains unknown. Here, we show that all three GPCRs preferentially interact with MRAP2 as 1:1 complexes and MRAP2 binding disrupts GPCR homodimerization. MRAP2 interacts with shared receptor transmembrane regions to promote GPCR signaling and impairs β-arrestin-2 recruitment to prolong signaling and delay internalization. Deletion of the MRAP2 cytoplasmic region impairs GPCR signaling by modulating constitutive activity. Human MRAP2 variants associated with overweight/obesity modify the constitutive activity of all three GPCRs. Thus, MRAP2 regulates GPCR function using shared molecular mechanisms, and we provide further evidence for the importance of GHSR constitutive activity. Show less

To investigate the metabolic mechanisms underlying weight regain (WR) after semaglutide withdrawal in females with obesity, focusing on gut microbiota, bile acid metabolism, and central nervous system regulation. In a prospective, single-arm interventional study, 28 women with obesity finished 36-week semaglutide treatment (2.4 mg/week) followed by 12-week withdrawal. Parallel animal studies used HFD-fed female rats with 4-week semaglutide intervention and 4-week withdrawal. Measurements included body weight, metabolic parameters, gut microbiota composition, bile acid profiles, and hypothalamic gene expression. During treatment, patients achieved significant weight loss (-16.9 ± 4.8 kg), but 71.4% exhibited WR (+5.1 ± 1.6 kg) post-withdrawal, with 78.5% reporting appetite rebound (≥30% increase in VAS score and a sustained ≥300 kcal/day rise). Animal studies showed post-withdrawal gut microbiota dysbiosis (increased Firmicutes/Bacteroidota ratio, reduced Clostridium sensu stricto 1), decreased ursodeoxycholic acid levels, and downregulated hypothalamic TGR5 expression. Hypothalamic orexigenic signaling (AgRP/NPY) rebounded while anorexigenic pathways (POMC/MC4R) attenuated. Improvements in hepatic and adipose lipid metabolism partially persisted through maintained AMPK/SIRT1 activation and AKT/mTOR suppression. The recurrence of WR and increased appetite after semaglutide withdrawal coincided with reversals in gut microbiota and related metabolic profiles. This pattern of changes may implicate gut-derived signals in the reactivation of central appetite pathways, providing a basis for investigating strategies to sustain weight loss. Show less

The melanocortin-4 receptor (MC4R) is highly expressed in the hypothalamus, and mutations in this gene are closely associated with the development of hereditary obesity and early-onset severe obesity in humans. Mc4r has been shown to be involved in the development of dilated cardiomyopathy. However, the current system for the early diagnosis and treatment of heart disease is not well established. In this study, we analyzed the effects of Mc4r knockout on cardiac function, cardiomyocyte morphology, fibrosis, and apoptosis in mice. Moreover, we explored the possible early molecular mechanisms by which Mc4r affects cardiac dysfunction via transcriptome sequencing of cardiac cells combined with bioinformatics analysis. Although the overall heart does not show organic changes, our study suggested that cardiomyocytes already show early abnormal changes at the molecular level. The sequencing results revealed that the genes that were differentially expressed between the two groups of mice were enriched mainly in the p53 signaling pathway and the hypoxia-inducible factor 1 (HIF-1) signaling pathway. We screened 10 key target genes via a protein-protein interaction (PPI) network and module analysis. Drugs targeting key genes were subsequently screened, and angiotensinogen (Agt) and Kit were identified as potential drug targets. We analyze relevant data through bioinformatics to screen for signaling pathways and key hub genes that are enriched in differentially expressed genes (DEGs), as well as molecules targeting the hub genes, in order to provide ideas for early prevention of heart disease caused by Mc4r gene defects or related obesity. Show less

Tirzepatide, a dual GLP-1/GIP receptor agonist, is recently approved for the treatment of type 2 diabetes and obesity in adults. Melanocortin-4-receptor (MC4R) deficiency is the most common monogenic cause of obesity and presents with hyperphagia and early onset obesity. While tirzepatide seems to be effective in inducing weight loss in adults with MC4R deficiency, its effects on hyperphagia and weight loss in pediatric patients are unexplored. A 17-year-old girl was admitted to our specialized obesity clinic because of hyperphagia and severe early-onset obesity due to MC4R deficiency. She had an extensive history of lifestyle interventions and psychological support and maintained a high level of physical activity. Despite these efforts, she presented with a BMI of 37 kg/m2 (3.68 SDS) and a substantial psychosocial burden. Vital signs and laboratory evaluations revealed no obesity-related complications. Tirzepatide was initiated at a dose of 2.5 mg weekly and slowly titrated to a maximum dose of 12.5 mg weekly. She initially experienced a substantial reduction in hyperphagia and reported less food noise, a reduction in hunger feelings and prolonged postprandial satiety. However, after 12 weeks hunger scores started to increase again, approaching pre-treatment levels at 28 weeks of follow-up. Metformin was added at 28 weeks in an attempt to better manage of hyperphagia, resulting in a reduction in hyperphagia. Despite these increasing hunger feelings from week 12 to 28, substantial weight loss was achieved, and the patient lost -13.9% of her initial body weight at 28 weeks. After addition of metformin, the patient lost an additional -7% of her weight. Total body weight reduction at week 37 was -20.9%. Tirzepatide was well tolerated, with no adverse effects reported at 41 weeks of follow-up. This case report suggests that tirzepatide is effective in reducing body weight in adolescents with MC4R deficiency. However, the question remains what the effect is on hunger and satiety in the long run and at a higher dose. Cohort studies are needed to assess long-term safety and effectiveness of tirzepatide in the pediatric population and in managing hyperphagia. Show less

The melanocortin-4 receptor (MC4R), a key regulator of energy balance and feeding behavior, plays a critical role in sheep growth. Herein, we identified a naturally occurring conserved functional SNP (g.59480661G > A, E100K, P.Glu100Lys) in the sheep MC4R gene. Using the Kompetitive Allele Specific PCR method, we detected this mutation in 2,151 sheep from six different breeds. Association analysis revealed that this mutation affects the growth traits of Luxi Blackhead sheep, and the individuals with AA (K100) genotype exhibited superior growth performance compared to the GG (E100) genotype. Additionally, whole-genome sequencing data from 49 sheep breeds, totaling 968 individuals, showed a higher mutation frequency of this variant in some large-sized sheep breeds. Functional studies demonstrated that the E100K mutation does not affect protein localization or transport but reduces surface and total protein expression. The mutated receptor exhibited decreased basal activity and reduced binding efficiency with agonists (α-MSH and β-MSH), resulting in a partial loss of function. Transcriptomic analysis indicated that this mutation affects downstream pathways, including osteoclast differentiation and the MAPK signaling pathway, which may influence growth regulation associated with the E100K mutation. Collectively, these findings underscore the substantial role of the partial loss-of-function MC4R E100K mutation in regulating growth traits in sheep. Show less

The BBSome, an eight-protein complex implicated in Bardet-Biedl syndrome (BBS), plays a crucial role in ciliary function. Although important aspects of its structural organization and protein interactions have been elucidated, additional questions remain regarding how these features relate to cargo recognition and complex dynamics. Using AlphaFold3, we generated a structural model closely matching recent cryo-EM data (Cα RMSD: 1.203 Å). Interface residue analysis of the model identified BBSome proteins BBS1 and BBS9 as central interaction hubs (most interface residues between two proteins), with BBS2 and BBS7 showing the most polar contacts. The common BBS1 Show less

The paraventricular hypothalamus (PVH) controls behavioral and physiologic processes, including appetite, social behavior, autonomic outflow, and pituitary hormone secretion. However, molecular markers for centrally projecting PVH neuron populations remain largely undefined, and a complete census of PVH cell types has not been established. Therefore, we performed extensive single-cell/nucleus RNA sequencing to catalog PVH neuron subtypes and multiplexed error-robust fluorescence in situ hybridization (MERFISH) to map them spatially. Our spatial transcriptomic atlas resolves 26 Sim1 Show less

Silica exposure precipitates irreversible lung injury; however, its long-term neurological sequelae—and the microglial mechanisms underlying these effects—remain poorly understood. Here, we demonstrate that inhaled crystalline silica induces persistent hippocampal inflammation, anxiety- and depression-like behaviors, and neuronal loss in mice. Bulk RNA sequencing, immunophenotyping, and pharmacological depletion studies revealed that microglia are the primary source of complement C1q in silica-exposed brains. Mechanistically, silica-induced lipocalin-2 (LCN2) engages the melanocortin-4 receptor (MC4R) on microglia, activating a cAMP/PKA/NF-κB cascade that transcriptionally upregulates C1q. Pharmacological blockade of MC4R (using PF) abolished C1q overproduction, normalized brain-derived neurotrophic factor levels, and restored both synaptic integrity and behavioral performance. Our findings establish the LCN2–MC4R–C1q axis as a critical microglial pathway in silica-related neurotoxicity and identify MC4R antagonism as a promising, readily translatable intervention for occupational neuroinflammation. The online version contains supplementary material available at 10.1186/s12974-026-03695-5. Show less

The regulation of appetite by pharmaceuticals has gained significant interest for the treatment of obesity and cachexia. The melanocortin 4 receptor (MC4R) and the ghrelin receptor (GhrR) are known to play a crucial role in the regulation of energy homeostasis. Thus, peptide ligands, which modulate these receptors, have become attractive therapeutic lead structures. A key challenge is the efficient delivery of such peptides to the targeted receptors, which are expressed in the hypothalamus. Therefore, direct nose-to-brain delivery is a compelling strategy. Here, we report on food intake that is modulated by using intranasal applied peptides. We synthesized fluorescently labelled variants of the MC4R agonist setmelanotide, the GhrR agonist ghrelin (Ghr) and the GhrR inverse agonist KbFwLL-NH Show less

Hypothalamic inflammation plays a key pathophysiological mechanism linking chronic consumption of a high fat diet (HFD) to the development of obesity and associated metabolic complications. Pilot studies report that oral glutamine (Gln) supplementation might reduce waist circumference and improve metabolic and inflammatory status in obesity patients. Although Gln metabolism plays a key role in intercellular communication in the central nervous system, its potential beneficial effects remain unexplored in these contexts. Here, we aimed to evaluate how stress and glutamine supplementation can modulate the hypothalamic response to HFD in mice using a chronic-restraint stress (CRS) model, which mimics IBS symptoms. From week 12 to week 14, mice received or not Gln diluted in drinking water (2 g/kg/day) and were placed in restraint tubes (2 h/day) for the last four consecutive days of protocol. Male and female obese mice showed a difference in vulnerability to CRS-induced effects. Moreover, mice responded to Gln supplementation in a sex-dependent manner, especially in stress conditions. Hypothalamic pathways regulating energy homeostasis were more impacted in male mice, whereas factors involved in neuroinflammation were more affected in female mice. Gln supplementation led to an increase in Mc4r and Bdnf mRNA levels and GFAP expression in male mice, while upregulated Iba1 and Il6 mRNA levels as well as signs of microgliosis were observed in stressed females. In conclusion, mice with obesity showed sex-specific hypothalamic response to glutamine supplementation and stress. Further investigations should be done to decipher underlying mechanisms. Show less

Mutations that impair the function of the melanocortin 4 receptor (MC4R) cause severe obesity in both heterozygous and homozygous carriers. However, recent findings indicate that individuals with this form of monogenic obesity may be unexpectedly protected against dyslipidemia and cardiovascular diseases. Show less

Melanocortin 4 receptor (MC4R) deficiency is the most common monogenic cause of obesity, yet remains underdiagnosed. Patients with monogenic obesity often undergo a frustrating diagnostic and therapeutic odyssey of years of ineffective lifestyle interventions before a causal diagnosis is made. We report a four-generation family where genetic testing in a child identified a likely pathogenic MC4R variant also carried by three ancestors. The studied family included a 7-year-old index patient, her mother, grandmother, and great-grandmother with a history of early-onset obesity. Panel sequencing of monogenic obesity genes was performed in the index patient whereas in the relatives targeted analysis of the familial MC4R variant was performed by Sanger sequencing. The index patient developed severe obesity by age 2 years, with hyperphagia, tall stature, and dyslipidemia. Despite lifestyle interventions, her body mass index (BMI) continued to increase. At the age of 7 years, genetic panel testing identified a rare monoallelic variant in the MC4R gene c.913C > T; p.Arg305Trp, previously shown to impair receptor function. Treatment with liraglutide (3.0 mg/day) was initiated at age 8 years, resulting in marked reduction in BMI during the first year of treatment. Subsequent genetic testing of family members identified the same variant in her mother, grandmother, and great-grandmother, all of whom had a history of early-onset obesity and related comorbidities, consistent with segregation of the variant within the family. This case underscores the importance of early genetic testing in severe childhood obesity to avoid ineffective treatments and enable targeted therapies (e.g., GLP-1 analogues). Diagnosing (likely) pathogenic MC4R variants can also identify at-risk relatives, providing psychological and clinical benefits across generations. Show less

The melanocortin-4 receptor (MC4R) is a G protein-coupled receptor with an essential role in appetite suppression and energy homeostasis. Genetic mutations in the receptor and components of its signalling pathway that cause obesity in humans, dogs and rodent models have revealed important insights into how the receptor signals and what regulates its cell surface expression. Structural studies have identified calcium as a critical cofactor for agonist binding and receptor function, while several transmembrane proteins have been shown to modulate MC4R activity. Here, we describe recent developments in our understanding of how accessory proteins and cofactors, identified using genomic approaches and screens for protein interaction, modify MC4R trafficking and signalling. We discuss how signalling by G Show less

The primary cause of death associated with opioids is opioid-induced respiratory depression (OIRD). Naloxone is used to reverse OIRD, but this drug is a competitive antagonist of µ-opioid receptor (MOR) and reverses analgesia, which limits its therapeutic use. Alternative non-opioid receptor antagonist-based approaches to OIRD treatment and prevention are needed. The aim of this study was to evaluate if setmelanotide (SET) is capable of reversing OIRD in a mouse model. C57BL/6J male and female mice and Sprague-Dawley rats were given IP morphine or fentanyl and then treated 15 min later with either SET or vehicle VEH (IP) in a random order. Breathing was recorded by barometric plethysmography, and pain sensitivity was measured by the tail-flick test. In mice with OIRD, SET induced a 3-fold reduction of the apnea index, and decreased apnea duration as compared to the VEH treatment. SET increased respiratory rate and did not affect opioid-induced analgesia. Photostimulation of MC4R+ ChR2-expressing fibers in the parafacial region of MC4R-Cre mice elicited short-latency excitatory postsynaptic current in rostral ventral respiratory group (rVRG) pre-motoneurons projecting to the phrenic nucleus in the C3-C4 ventral horns of the spinal cord. Fentanyl inhibited the activity of rVRG neurons and SET reversed this effect. SET effectively treated OIRD by increasing respiratory rate and inducing a significant decrease in the number of apneas without decreasing analgesia. Show less

Genetic factors are thought to play an important role in antipsychotic-induced weight gain (AIWG). Polygenic risk scores (PRS) could provide a measure of genetic predisposition to antipsychotic drug induced weight gain (AIWG).We conducted a study to examine how a PRS, generated using SNPs, identified from a recent meta-analysis, related to weight-change over time in people with first episode-psychosis. The PRS included SNPs in six different genes, identified as having significant associations (p < 0.05) with AIWG. These were HTR2C rs3813929; MTHFR rs1801133; ADRA2A rs1800544; MC4R rs489693; LEPR rs1137101 and CNR1 rs1049353. An additive PRS and a risk allele based weighted PRS were created based on risk allele counts and presence or absence of risk alleles respectively. The additive PRS was also used to create low/high genetic risk groups for analysis. The association between PRS and weight gain per day (WGPD) in grams/day as well as BMI percentage change (=> 7%) was investigated using regression models. In multiple regression analysis, the additive PRS significantly predicted AIWG in females (adjusted r We report a PRS that is predictive of weight gain in women treated for first episode psychosis, accounting for 59% of the variance daily weight-gain over time. Validation in an independent cohort is required, as is determining whether it is feasible to apply the PRS prospectively. Show less

Precision nutrition, guided by genetic testing, has emerged as a promising approach for managing obesity. However, robust clinical trials testing its effectiveness in real-world dietary interventions remain scarce. The GenOn Programme aims to evaluate whether tailoring nutritional care based on genetic risk for obesity enhances weight loss, satiety control, and metabolic outcomes in adults with overweight and obesity. The GenOn Programme is an 18-week, 2 × 2 factorial, randomised controlled trial including 120 adults classified as high or low genetic risk for obesity (variants: FTO rs9939609 and rs1121980; MC4R rs1782313; LEP rs7799039). Participants are randomised to standard or satiety-focused dietary counselling. Both groups receive five calorie-restricted (-500 kcal/day), nutritionally balanced meal plans. The satiety arm additionally includes a high-protein breakfast, daily granola supplementation and behavioural strategies. Assessments at baseline, Week 12, and Week 18 include weight loss, body composition, satiety perception, quality of life, cardiometabolic markers, (epi)genetics, inflammation, neuroendocrine regulation, and metagenomics. The GenOn Programme is a randomised controlled trial to test a precision nutrition approach for overweight and obesity, integrating genetics, dietary strategies, and behavioural support. Findings may inform dietitians and healthcare systems on the clinical value of genetically guided nutritional care to improve outcomes in the treatment of overweight and obesity. Show less

Chronic obesity is associated with impaired bone health. However, few investigations have been conducted to assess bone physiology in early-onset obesity. In this study, we measured specific bone turnover and metabolic biomarkers in children with severe obesity with biallelic loss-of-function variants of the leptin (LEP), leptin receptor (LEPR), or melanocortin 4 receptor (MC4R) genes. Thirty-nine children aged 0.3-8.8 years with a BMI SDS ≥ 3, previously identified with pathogenic variants in LEP, LEPR, or MC4R, were recruited for the current study. Additionally, 13 age-matched children with severe obesity who tested negative for variants in known obesity-related genes were included, and another 13 unrelated age-matched children with normal body weight served as the control group. Serum osteocalcin, osteopontin, osteoprotegerin, and sclerostin levels were assessed using multi-analyte profiling. Serum leptin, insulin, and cortisol levels were determined using ELISA. Serum levels of osteocalcin and osteopontin, specific markers of bone formation, were significantly lower in children with LEP and LEPR biallelic variants than in the control group. In contrast, the values of these two biomarkers in children with MC4R deficiency were significantly higher than those in the other groups. No differences were observed in the bone resorption markers osteoprotegerin and sclerostin. Hyperleptinemia was more pronounced in children with LEPR deficiency. Serum insulin concentrations were elevated in individuals with MC4R deficiency, whereas serum cortisol levels were significantly higher in children with LEP deficiency than in all other groups. Our data demonstrate that osteogenic activity (but not resorption activity) is differentially affected in children with complete genetic disruption of the leptin-signaling pathway. Children with MC4R deficiency showed higher osteogenic markers, but children with LEP and LEPR deficiencies showed the opposite. Our results support the usefulness of bone turnover biomarkers for the assessment and management of bone health in different types of obesity. Show less

Hypothalamic neurons expressing either POMC or AGRP sense nutritional state directly and indirectly and transmit these neuropeptide signals to other brain centres through the melanocortin 3 and 4 receptors. MC4R is primarily concerned with the control of appetite and energy expenditure while MC3R is more closely related to the control of linear growth and the timing of puberty. The role of MC3R in the long-term control of energy balance and body composition is less clear, particularly in humans. We have undertaken studies in humans, domestic dogs and mice with the goal of clarifying the relative impact of MC3R deficiency on energy balance, growth and sexual development. By studying three large consanguineously enriched cohorts, totalling approximately 300K people, we identified nine individuals who are homozygous for functionally null MC3R variants. The body mass index (BMI) of the homozygous MC3R variant carriers was not significantly different from that of age, sex and demographically matched controls, with six of the nine homozygotes having a BMI <30 kg/m Show less