Systematic Data Mining Reveals Synergistic H3R/MCHR1 Ligands.
ABSTRACT: In this study, we report a ligand-centric data mining approach that guided the identification of suitable target profiles for treating obesity. The newly developed method is based on identifying target pairs for synergistic positive effects and also encompasses the exclusion of compounds showing a detrimental effect on obesity treatment (off-targets). Ligands with known activity against obesity-relevant targets were compared using fingerprint representations. Similar compounds with activities to different targets were evaluated for the mechanism of action since activation or deactivation of drug targets determines the pharmacological effect. In vitro validation of the modeling results revealed that three known modulators of melanin-concentrating hormone receptor 1 (MCHR1) show a previously unknown submicromolar affinity to the histamine H3 receptor (H3R). This synergistic activity may present a novel therapeutic option against obesity.
Project description:[11C]SNAP-7941 and its radiofluorinated, fluoro-ethyl derivative [18F]FE@SNAP have been developed as the first positron emission tomography tracers for melanin-concentrating hormone receptor 1 (MCHR1) imaging. Accumulation of these MCHR1 PET-tracers in rat brown adipose tissue (BAT) in vivo provided first indication of MCHR1 expression in rodent BAT. To rule out off-target binding, affinity of both MCHR1 ligands toward adrenergic beta-3 receptors (ADRB3) was examined. Further, specific binding of [11C]SNAP-7941 to brown adipocytes and effects of MCHR1 ligands on brown adipocyte activation were investigated. SNAP-7941 and FE@SNAP evinced to be highly selective toward MCHR1. [11C]SNAP-7941 binding to brown adipocytes was shown to be mainly MCHR1-specific. This data strongly indicates MCHR1 expression in rodent BAT and moreover, a peripheral, anti-obesity effect of MCHR1 antagonists directly exerted in BAT is proposed. Moreover, MCHR1 expression in murine brown adipocytes was confirmed by protein and mRNA analysis. We conclude that MCHR1 PET imaging contributes to basic research in endocrinology by elucidating the involvement of the MCH system in peripheral tissues, such as BAT.
Project description:Melanin-concentrating hormone (MCH) regulates food intake through activation of the receptor, MCHR1. We have identified AMG 076 as an orally bioavailable potent and selective small molecule antagonist of MCHR1. In mouse models of obesity, AMG 076 caused a reduction in body weight gain in wild-type (MCHR1+/+) but not in knockout (MCHR1-/-) mice. The body weight reduction was associated with decreases in food intake and increases in energy expenditure. Importantly, we show that these MCHR1-dependent effects of AMG 076 were also reflected in improved metabolic phenotypes, increased glucose tolerance and insulin sensitivity. Preliminary data on effects of AMG 076 in obese cynomolgus monkeys are also presented.
Project description:Several encouraging pre-clinical results highlight the melanin-concentrating hormone receptor 1 (MCHR1) as promising target for anti-obesity drug development. Currently however, experimentally resolved structures of MCHR1 are not available, which complicates rational drug design campaigns. In this study, we aimed at developing accurate, homologymodel-based 3D pharmacophores against MCHR1. We show that traditional approaches involving docking of known active small molecules are hindered by the flexibility of binding pocket residues. Instead, we derived three-dimensional pharmacophores from molecular dynamics simulations by employing our novel open-source software PyRod. In a retrospective evaluation, the generated 3D pharmacophores were highly predictive returning up to 35?% of active molecules and showing an early enrichment (EF1) of up to 27.6. Furthermore, PyRod pharmacophores demonstrate higher sensitivity than ligand-based pharmacophores and deliver structural insights, which are key to rational lead optimization.
Project description:BACKGROUND: Melanin-concentrating hormone receptor 1 (MCHR1) plays a significant role in regulation of energy balance, food intake, physical activity and body weight in humans and rodents. Several association studies for human obesity showed contrary results concerning the SNPs rs133072 (G/A) and rs133073 (T/C), which localize to the first exon of MCHR1. The variations constitute two main haplotypes (GT, AC). Both SNPs affect CpG dinucleotides, whereby each haplotype contains a potential methylation site at one of the two SNP positions. In addition, 15 CpGs in close vicinity of these SNPs constitute a weak CpG island. Here, we studied whether DNA methylation in this sequence context may contribute to population- and age-specific effects of MCHR1 alleles in obesity. PRINCIPAL FINDINGS: We analyzed DNA methylation of a 315 bp region of MCHR1 encompassing rs133072 and rs133073 and the CpG island in blood samples of 49 individuals by bisulfite sequencing. The AC haplotype shows a significantly higher methylation level than the GT haplotype. This allele-specific methylation is age-dependent. In young individuals (20-30 years) the difference in DNA methylation between haplotypes is significant; whereas in individuals older than 60 years it is not detectable. Interestingly, the GT allele shows a decrease in methylation status with increasing BMI, whereas the methylation of the AC allele is not associated with this phenotype. Heterozygous lymphoblastoid cell lines show the same pattern of allele-specific DNA methylation. The cell line, which exhibits the highest difference in methylation levels between both haplotypes, also shows allele-specific transcription of MCHR1, which can be abolished by treatment with the DNA methylase inhibitor 5-aza-2'-deoxycytidine. CONCLUSIONS: We show that DNA methylation at MCHR1 is allele-specific, age-dependent, BMI-associated and affects transcription. Conceivably, this epigenetic regulation contributes to the age- and/or population specific effects reported for MCHR1 in several human obesity studies.
Project description:Melanin concentrating hormone receptor 1 (MCHR1), a crucial regulator of energy homeostasis involved in the control of feeding and energy metabolism, is a promising target for treatment of obesity. In the present work, the up-to-date largest set of 181 quinoline/quinazoline derivatives as MCHR1 antagonists was subjected to both ligand- and receptor-based three-dimensional quantitative structure-activity (3D-QSAR) analysis applying comparative molecular field analysis (CoMFA) and comparative molecular similarity indices analysis (CoMSIA). The optimal predictable CoMSIA model exhibited significant validity with the cross-validated correlation coefficient (Q²) = 0.509, non-cross-validated correlation coefficient (R²(ncv)) = 0.841 and the predicted correlation coefficient (R²(pred)) = 0.745. In addition, docking studies and molecular dynamics (MD) simulations were carried out for further elucidation of the binding modes of MCHR1 antagonists. MD simulations in both water and lipid bilayer systems were performed. We hope that the obtained models and information may help to provide an insight into the interaction mechanism of MCHR1 antagonists and facilitate the design and optimization of novel antagonists as anti-obesity agents.
Project description:Changes in the expression of the melanin concentrating hormone receptor 1 (MCHR1) are involved in a variety of pathologies, especially obesity and anxiety disorders. To monitor these pathologies in-vivo positron emission tomography (PET) is a suitable method. After the successful radiosynthesis of [(11)C]SNAP-7941-the first PET-Tracer for the MCHR1, we aimed to synthesize its [(18)F]fluoroethylated analogue: [(18)F]FE@SNAP. Therefore, microfluidic and vessel-based approaches were tested. [(18)F]fluoroethylation was conducted via various [(18)F]fluoroalkylated synthons and direct [(18)F]fluorination. Only the direct [(18)F]fluorination of a tosylated precursor using a flow-through microreactor was successful, affording [(18)F]FE@SNAP in 44.3 ± 2.6%.
Project description:Melanin-concentrating hormone (MCH) is a hypothalamic neuropeptide that acts via MCH receptor 1 (MCHR1) in the mouse. It promotes positive energy balance; thus, mice lacking MCH or MCHR1 are lean, hyperactive, and resistant to diet-induced obesity. Identifying the cellular targets of MCH is an important step to understanding the mechanisms underlying MCH actions. We generated the Mchr1-cre mouse that expresses cre recombinase driven by the MCHR1 promoter and crossed it with a tdTomato reporter mouse. The resulting Mchr1-cre/tdTomato progeny expressed easily detectable tdTomato fluorescence in MCHR1 neurons, which were found throughout the olfactory system, striatum, and hypothalamus. To chemically identify MCH-targeted cell populations that play a role in energy balance, MCHR1 hypothalamic neurons were characterized by colabeling select hypothalamic neuropeptides with tdTomato fluorescence. TdTomato fluorescence colocalized with dynorphin, oxytocin, vasopressin, enkephalin, thyrothropin-releasing hormone, and corticotropin-releasing factor immunoreactive cells in the paraventricular nucleus. In the lateral hypothalamus, neurotensin, but neither orexin nor MCH neurons, expressed tdTomato. In the arcuate nucleus, both Neuropeptide Y and proopiomelanocortin cells expressed tdTomato. We further demonstrated that some of these arcuate neurons were also targets of leptin action. Interestingly, MCHR1 was expressed in the vast majority of leptin-sensitive proopiomelanocortin neurons, highlighting their importance for the orexigenic actions of MCH. Taken together, this study supports the use of the Mchr1-cre mouse for outlining the neuroanatomical distribution and neurochemical phenotype of MCHR1 neurons.
Project description:Although extensive research on brown adipose tissue (BAT) has stimulated optimism in the battle against obesity and diabetes, BAT physiology and organ crosstalk are not fully understood. Besides BAT, melanin-concentrating hormone (MCH) and its receptor (MCHR1) play an important role in energy homeostasis. Because of the link between hypothalamic MCH neurons and sympathetic BAT activation via β-adrenoceptors, we investigated the expression and physiological role of the MCHR1 in BAT. MCHR1 was detected in rodent and human BAT with RT-qPCR and western blot analyses. In vivo imaging in rats used the glucose analog [<sup>18</sup> F]FDG and the MCHR1-tracer [<sup>11</sup> C]SNAP-7941. We found that the β3-adrenoceptor (ADRB3) agonist CL316,243 increased [<sup>11</sup> C]SNAP-7941 uptake in BAT. Additionally, a pharmacological concentration of SNAP-7941-a low-affinity ADRB3 ligand-stimulated [<sup>18</sup> F]FDG uptake, reflecting BAT activation. In cultured human adipocytes, CL316,243 induced MCHR1 expression, further supporting a direct interaction between MCHR1 and ADRB3. These findings characterized MCHR1 expression in rodent and human BAT for the first time, including in vitro and in vivo data demonstrating a link between MCHR1 and the β3-adrenergic system. The presence of MCHR1 in BAT emphasizes the role of BAT in energy homeostasis and may help uncover treatment approaches for obesity.
Project description:The neuropeptide, melanin concentrating hormone (MCH), and its G protein-coupled receptor, melanin concentrating hormone receptor 1 (Mchr1), are expressed centrally in adult rodents. MCH signaling has been implicated in diverse behaviors such as feeding, sleep, anxiety, as well as addiction and reward. While a model utilizing the Mchr1 promoter to drive constitutive expression of Cre recombinase (Mchr1-Cre) exists, there is a need for an inducible Mchr1-Cre to determine the roles for this signaling pathway in neural development and adult neuronal function. Here, we generated a BAC transgenic mouse where the Mchr1 promotor drives expression of tamoxifen inducible CreER recombinase. Many aspects of the Mchr1-Cre expression pattern are recapitulated by the Mchr1-CreER model, though there are also notable differences. Most strikingly, compared to the constitutive model, the new Mchr1-CreER model shows strong expression in adult animals in hypothalamic brain regions involved in feeding behavior but diminished expression in regions involved in reward, such as the nucleus accumbens. The inducible Mchr1-CreER allele will help reveal the potential for Mchr1 signaling to impact neural development and subsequent behavioral phenotypes, as well as contribute to the understanding of the MCH signaling pathway in terminally differentiated adult neurons and the diverse behaviors that it influences.
Project description:We identified several differentially expressed genes in dermal fibroblasts from patients with SSc compared to their healthy twins, including the upregulation of MCHR1 in SSc fibroblasts. We also uncovered MCHR1 as a hub gene with the highest centrality degree in the network analysis, suggesting important biological role. We identified PDGF as the pro-fibrotic growth factor that increases MCHR1 levels. We further determine that PDGF induction of dermal fibroblast activation and pro-fibrotic factor production is mediating by MCHR1 using silencing and chemical inhibition of MCHR1. Overall design: Compare the expression profiling of primary human skin fibroblasts from healthy donors transfected with siRNA to silence MCHR1 with PDGFBB or vehicle treatment