Disruption of hypothalamic melanocortin 4 receptors (MC4Rs) causes obesity in mice and humans. Here, we investigated the transcriptional regulation of in the hypothalamus. In mice, we show that the homeodomain transcription factor Orthopedia (OTP) is enriched in MC4R neurons in the paraventricular nucleus (PVN) of the hypothalamus and directly regulates transcription.
View Article and Find Full Text PDFThis study focuses on the synthesis of a novel Cerium-Magnesium (CeO-MgO) binary oxide nanomaterials by a simple co-precipitation process and used to remove harmful pollutants such as Cr(VI), Cu(II), and F. The morphology, phase, crystallite size, thermal stability, functional groups, surface area, and porosity of the synthesized nanomaterial were determined by using XRD, SEM, FTIR, TGA/DTA, and BET studies. The prepared nanomaterials showed adsorption selectivity of Cu(II) ≈ F> Cr(VI) with a high adsorption capacity of 84.
View Article and Find Full Text PDFBackground: Setmelanotide, a melanocortin-4 receptor (MC4R) agonist, has been shown to reduce hunger and weight in patients aged 6 years and older with proopiomelanocortin (POMC) deficiency (including biallelic variants in proprotein convertase subtilisin/kexin type 1 [PCSK1]), leptin receptor (LEPR) deficiency, or Bardet-Biedl syndrome (BBS). No approved therapies for patients younger than 6 years old currently exist. The phase 3, open-label VENTURE trial aimed to evaluate the efficacy and safety of setmelanotide in patients aged 2-5 years with POMC or LEPR deficiency or BBS.
View Article and Find Full Text PDFLancet Diabetes Endocrinol
January 2025
Despite the diverse nature of obesity, there is compelling genetic, clinical, and experimental evidence that endorses the important contribution of brain circuits to this condition. The hypothalamus contains major regulatory circuits for bodyweight homoeostasis, the deregulation of which can lead to obesity. Although functional perturbation of hypothalamic pathways could lie at the basis of common forms of obesity, the term hypothalamic obesity has been created to define those rare forms of severe obesity where a clear hypothalamic substrate can be identified, either of genetic or acquired origin.
View Article and Find Full Text PDFProtein Tyrosine Phosphatase 1B (PTP1B) is a negative regulator of leptin signaling whose disruption protects against diet-induced obesity in mice. We investigated whether structural characterization of human PTP1B variant proteins might reveal precise mechanisms to target for weight loss therapy. We selected 12 rare variants for functional characterization from exomes from 997 people with persistent thinness and 200,000 people from UK Biobank.
View Article and Find Full Text PDFObesity causes significant morbidity and mortality globally. Research in the last three decades has delivered a step-change in our understanding of the fundamental mechanisms that regulate energy homeostasis, building on foundational discoveries in mouse models of metabolic disease. However, not all findings made in rodents have translated to humans, hampering drug discovery in this field.
View Article and Find Full Text PDFThe hormone leptin, primarily secreted by adipocytes, plays a crucial role in regulating whole-body energy homeostasis. Homozygous loss-of-function mutations in the leptin gene (LEP) cause hyperphagia and severe obesity, primarily through alterations in leptin's affinity for its receptor or changes in serum leptin concentrations. Although serum concentrations are influenced by various factors (e.
View Article and Find Full Text PDFHypothalamic neural circuits regulate instinctive behaviors such as food seeking, the fight/flight response, socialization, and maternal care. Here, we identified microdeletions on chromosome Xq23 disrupting the brain-expressed transient receptor potential (TRP) channel 5 (TRPC5). This family of channels detects sensory stimuli and converts them into electrical signals interpretable by the brain.
View Article and Find Full Text PDFDeclined memory is a hallmark of Alzheimer's disease (AD). Experiments in rodents and human postmortem studies suggest that serotonin (5-hydroxytryptamine, 5-HT) plays a role in memory, but the underlying mechanisms are unknown. Here, we investigate the role of 5-HT 2C receptor (5-HTR) in regulating memory.
View Article and Find Full Text PDFObesity is a major risk factor for many common diseases and has a substantial heritable component. To identify new genetic determinants, we performed exome-sequence analyses for adult body mass index (BMI) in up to 587,027 individuals. We identified rare loss-of-function variants in two genes (BSN and APBA1) with effects substantially larger than those of well-established obesity genes such as MC4R.
View Article and Find Full Text PDFPurpose: Biallelic pathogenic leptin gene variants cause severe early-onset obesity usually associated with low or undetectable circulating leptin levels. Recently, variants have been described resulting in secreted mutant forms of the hormone leptin with either biologically inactive or antagonistic properties.
Methods: We conducted a systematic literature research supplemented by unpublished data from patients at our center as well as new in vitro analyses to provide a systematic classification of congenital leptin deficiency based on the molecular and functional characteristics of the underlying leptin variants and investigated the correlation of disease subtype with severity of the clinical phenotype.
Mutations that perturb leptin-melanocortin signaling are known to cause hyperphagia and obesity, but energy expenditure has not been well studied outside rodents. We report on a common canine mutation in pro-opiomelanocortin (), which prevents production of β-melanocyte-stimulating hormone (β-MSH) and β-endorphin but not α-MSH; humans, similar to dogs, produce α-MSH and β-MSH from the propeptide, but rodents produce only α-MSH. We show that energy expenditure is markedly lower in affected dogs, which also have increased motivational salience in response to a food cue, indicating increased wanting or hunger.
View Article and Find Full Text PDFJ Int Soc Prev Community Dent
December 2023
Aim: To quantify and compare the metal ions released from different bracket-wire combinations and to assess their cytotoxicity.
Materials And Methods: A total of 360 fabricated sectional fixed orthodontic appliances were divided into 6 groups. The first three groups consisted of stainless-steel brackets with stainless-steel, snickel-titanium (NiTi), and titanium-molybdenum alloy (TMA) archwires, and the other three groups were fabricated using ceramic brackets (polycrystalline alumina) with stainless-steel, NiTi, and TMA archwires.
Although overconsumption of high-fat foods is a major driver of weight gain, the neural mechanisms that link the oral sensory properties of dietary fat to reward valuation and eating behavior remain unclear. Here we combine novel food-engineering approaches with functional neuroimaging to show that the human orbitofrontal cortex (OFC) translates oral sensations evoked by high-fat foods into subjective economic valuations that guide eating behavior. Male and female volunteers sampled and evaluated nutrient-controlled liquid foods that varied in fat and sugar ("milkshakes").
View Article and Find Full Text PDFThe long-term clinical outcomes of severe obesity due to leptin signaling deficiency are unknown. We carry out a retrospective cross-sectional investigation of a large cohort of children with leptin (LEP), LEP receptor (LEPR), or melanocortin 4 receptor (MC4R) deficiency (n = 145) to evaluate the progression of the disease. The affected individuals undergo physical, clinical, and metabolic evaluations.
View Article and Find Full Text PDFObesity contributes substantially to the global burden of disease and has a significant heritable component. Recent large-scale exome sequencing studies identified several genes in which rare, protein-coding variants have large effects on adult body mass index (BMI). Here we extended such work by performing sex-stratified associations in the UK Biobank study (N∼420,000).
View Article and Find Full Text PDFPubertal timing varies considerably and has been associated with a range of health outcomes in later life. To elucidate the underlying biological mechanisms, we performed multi-ancestry genetic analyses in ~800,000 women, identifying 1,080 independent signals associated with age at menarche. Collectively these loci explained 11% of the trait variance in an independent sample, with women at the top and bottom 1% of polygenic risk exhibiting a ~11 and ~14-fold higher risk of delayed and precocious pubertal development, respectively.
View Article and Find Full Text PDFHormone absence or inactivity is common in congenital disease, but hormone antagonism remains controversial. Here, we characterize two novel homozygous leptin variants that yielded antagonistic proteins in two unrelated children with intense hyperphagia, severe obesity, and high circulating levels of leptin. Both variants bind to the leptin receptor but trigger marginal, if any, signaling.
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