Anorexigenic Neuropeptides Research Articles

Comparison of orexigenic and anorexigenic neuropeptide levels in hyperemesis gravidarum patients with normal pregnant women: A prospective cohort study.

The aim of this study was to determine whether orexigenic neuropeptides, orexin and galanin, and anorexigenic neuropeptides, alpha-melanocyte-stimulating hormone (α-MSH) and cocaine- and amphetamine-regulated transcript (CART), are implicated in hyperemesis gravidarum (HG). Fifty pregnant women who had been diagnosed with HG between April 2022 and February 2023 at the Siirt University Faculty of Medicine Training and Research Hospital (tertiary center) were recruited for this study. An equal number of pregnant women without an HG diagnosis were included in the study as the control group. Participants' age, pregnancy history, medical history, thyroid function test results, complete blood count results, and electrolyte levels were recorded, and their orexin, galanin, α-MSH, and CART serum levels were analyzed using an enzyme-linked immunosorbent assay. No statistically significant differences in orexigenic neuropeptides (orexin and galanin) were observed between the HG and control groups. A statistical difference was found between an anorexigenic neuropeptide (α-MSH) and the control group (P = .012). Based on a receiver operating characteristic analysis, the α-MSH parameter was statistically significant for distinguishing between participants with an HG diagnosis and those without, with a sensitivity of 63.6%, specificity of 65.9%, and cutoff value of 11769.3 pg/mL (P = .012, area under curve: 0.655). Based on the severity classification of ketonuria (ketonuria levels of +1 or +2 were classified as mild, whereas levels of +3 or +4 were classified as moderate to severe), the anorexigenic CART neuropeptide was found to be a statistically significant diagnostic indicator of severe ketonuria (P = .020). α-MSH and CART levels were found to be related in HG patients and in HG patients with severe ketonuria.

Hypothalamic integration of nutrient sensing in fish.

The hypothalamus plays a crucial role in regulating feeding behavior in fish. In this Review, we aim to summarise current knowledge on specific mechanisms for sensing glucose, fatty acids and amino acids in fish, and to consider how this information is integrated in the hypothalamus to modulate feed intake. In fish, specific neuronal populations in the nucleus lateralis tuberalis (NLTv) of the hypothalamus are equipped with nutrient sensors and hormone receptors, allowing them to respond to changes in metabolite levels and hormonal signals. These neurons produce orexigenic (Npy and Agrp) and anorexigenic (Pomc and Cart) neuropeptides, which stimulate and suppress appetite, respectively. The modulation of feeding behavior involves adjusting the expression of these neuropeptides based on physiological conditions, ultimately influencing feeding through reciprocal inhibition of anorexigenic and orexigenic neurons and signalling to higher-order neurons. The activation of nutrient sensors in fish leads to an enhanced anorexigenic effect, with downregulation of agrp and npy, and upregulation of cart and pomc. Connections between hypothalamic neurons and other populations in various brain regions contribute to the intricate regulation of feeding behaviour in fish. Understanding how feed intake is regulated in fish through these processes is relevant to understanding fish evolution and is also important in the context of aquaculture.

Lipidized analogues of the anorexigenic CART (cocaine- and amphetamine-regulated transcript) neuropeptide show anorexigenic and neuroprotective potential in mouse model of monosodium-glutamate induced obesity

AimsThis study investigates the neuroprotective effects of lipidized analogues of 2-SS-CART(61–102) derived from anorexigenic neuropeptide cocaine- and amphetamine-regulated transcript peptide (CARTp) in light of the link between obesity, its comorbidities, and the development of Alzheimer's disease. MethodsWe introduce novel lipidized analogues derived from 2-SS-CART(61–102), a specific analogue of natural CART(61–102), with two disulfide bridges. Using hypothermic PC12 cells, we tested the effect of the most potent analogues on Tau phosphorylation. We further described the anorexigenic and neuroprotective potential of subcutaneously (SC) injected lipidized CARTp analogue in a mouse model with prediabetes and obesity induced by neonatal monosodium glutamate (MSG) administration. ResultsCompared to the non-lipidized 2-SS-CART(61–102), all lipidized analogues exhibited a potent binding affinity to PC12 cells and enhanced in vitro stability in rat plasma. Two most potent lipidized analogues attenuated hypothermia-induced Tau hyperphosphorylation at multiple epitopes. Subsequently, chronic SC treatment with palm-2-SS-CART(61–102) significantly decreased body weight and food intake, improved metabolic parameters, decreased level of pTau and increased neurogenesis in hippocampi of obese MSG mice. ConclusionOur unique CARTp analogue palm-2-SS-CART(61–102) shows promise as a potent anti-obesity and neuroprotective agent.

Long-Term Dynamics of Serum α-MSH and α-MSH-Binding Immunoglobulins with a Link to Gut Microbiota Composition in Patients with Anorexia Nervosa

Introduction: Immunoglobulins (Ig) reactive with α-melanocyte-stimulating hormone (α-MSH), an anorexigenic neuropeptide, are present in humans and were previously associated with eating disorders. In this longitudinal study involving patients with anorexia nervosa (AN), we determined whether α-MSH in serum is bound to IgG and analyzed long-term dynamics of both α-MSH peptide and α-MSH-reactive Ig in relation to changes in BMI and gut microbiota composition. Methods: The study included 64 adolescents with a restrictive form of AN, whose serum samples were collected at hospital admission, discharge, and during a 1-year follow-up visit and 41 healthy controls, all females. Results: We found that in both study groups, approximately 40% of serum α-MSH was reversibly bound to IgG and that levels of α-MSH-reactive IgG but not of α-MSH peptide in patients with AN were low at hospital admission but recovered 1 year later. Total IgG levels were also low at admission. Moreover, BMI-standard deviation score correlated positively with α-MSH IgG in both groups studied but negatively with α-MSH peptide only in controls. Significant correlations between the abundance of specific bacterial taxa in the gut microbiota and α-MSH peptide and IgG levels were found in both study groups, but they were more frequent in controls. Conclusion: We conclude that IgG in the blood plays a role as an α-MSH-binding protein, whose characteristics are associated with BMI in both patients with AN and controls. Furthermore, the study suggests that low production of α-MSH-reactive IgG during the starvation phase in patients with AN may be related to altered gut microbiota composition.

Phyllanthus emblica Fruit Improves Obesity by Reducing Appetite and Enhancing Mucosal Homeostasis via the Gut Microbiota-Brain-Liver Axis in HFD-Induced Leptin-Resistant Rats.

The impact of leptin resistance on intestinal mucosal barrier integrity, appetite regulation, and hepatic lipid metabolism through the microbiota-gut-brain-liver axis has yet to be determined. Water extract of Phyllanthus emblica L. fruit (WEPE) and its bioactive compound gallic acid (GA) effectively alleviated methylglyoxal (MG)-triggered leptin resistance in vitro. Therefore, this study investigated how WEPE and GA intervention relieve leptin resistance-associated dysfunction in the intestinal mucosa, appetite, and lipid accumulation through the microbiota-gut-brain-liver axis in high-fat diet (HFD)-fed rats. The results showed that WEPE and GA significantly reduced tissues (jejunum, brain, and liver) MG-evoked leptin resistance, malondialdehyde (MDA), proinflammatory cytokines, SOCS3, orexigenic neuropeptides, and lipid accumulation through increasing leptin receptor, tight junction proteins, antimicrobial peptides, anorexigenic neuropeptides, excretion of fecal triglyceride (TG), and short-chain fatty acids (SCFAs) via a positive correlation with the Allobaculum and Bifidobacterium microbiota. These novel findings suggest that WEPE holds the potential as a functional food ingredient for alleviating obesity and its complications.

Anorexigenic neuropeptides as anti-obesity and neuroprotective agents: exploring the neuroprotective effects of anorexigenic neuropeptides.

Since 1975, the incidence of obesity has increased to epidemic proportions, and the number of patients with obesity has quadrupled. Obesity is a major risk factor for developing other serious diseases, such as type 2 diabetes mellitus, hypertension, and cardiovascular diseases. Recent epidemiologic studies have defined obesity as a risk factor for the development of neurodegenerative diseases, such as Alzheimer's disease (AD) and other types of dementia. Despite all these serious comorbidities associated with obesity, there is still a lack of effective antiobesity treatment. Promising candidates for the treatment of obesity are anorexigenic neuropeptides, which are peptides produced by neurons in brain areas implicated in food intake regulation, such as the hypothalamus or the brainstem. These peptides efficiently reduce food intake and body weight. Moreover, because of the proven interconnection between obesity and the risk of developing AD, the potential neuroprotective effects of these two agents in animal models of neurodegeneration have been examined. The objective of this review was to explore anorexigenic neuropeptides produced and acting within the brain, emphasizing their potential not only for the treatment of obesity but also for the treatment of neurodegenerative disorders.

Production of Aroma-Rich Extracts from Sardine Cooking Wastewaters: Exploring Their Potential for Modulating Feed Intake in European Seabass

Managing the canning industry’s nutrient-rich and odorous liquid waste is a hurdle. Concurrently, the growing use of vegetable ingredients in aquafeeds diminishes palatability and feed consumption in carnivorous fish. Thus, we hypothesized that aromas could be extracted from cooking wastewaters at canning factories and added to plant-based diets to stimulate intake in European seabass. Sardine cooking wastewaters were collected and tested directly (CW-A) or after vacuum distillation (VD-A) or liquid/liquid extraction with soybean oil (LLE-A). Despite losses in aldehydes and short-chain alcohols, both processes were effective in removing off-flavours. VD-A displayed a higher concentration of most aromas compared to LLE-A. Extracts were included at 2 μg g−1 of 1-penten-3-ol, the most abundant compound in all extracts, in diets (CW, VD, LLE). A non-supplemented diet was used as control. Each diet was assigned to six groups of juvenile fish, fed a single meal until apparent satiation. Our emphasis was on this initial feeding to comprehend the hedonic control of feed intake, minimizing habituation effects and the impact of the long-term metabolic requirements. Feed intake was highest for the control group. No differences on plasma metabolites were observed, suggesting feed intake was primarily regulated by hedonic rather than homeostatic mechanisms. Moreover, the lower intake in the supplemented diets was partially associated with a lower expression of orexigenic (intake-promoting) neuropeptides and higher expression of anorexigenic (intake-reducing) neuropeptides in the brain, despite the lack of significant diet-related differences. Overall, this study presents a novel approach to valorise cooking wastewater from the canning industry, since cooking wastewaters extracts rich in aromas were successfully produced, however, in the tested concentration, had no positive impact on the short-term feed intake response of European seabass.Graphical

The Role of Physical Exercise in Food Intake Suppression

Obesity is a global health issue since it is related to diseases that are the leading causes of mortality, such as diabetes, stroke, and cardiovascular disease. A long-term imbalance between energy intake and energy expenditure is one of the factors contributing to obesity. In addition to increasing energy expenditure, physical exercise can also aid in weight loss by decreasing food intake. An increase in appetite-regulating hormones (ghrelin, GLP-1, leptin, and adiponectin), myokines (IL-6 and irisin), and lactate mediates the suppression of food intake during physical exercise. These substances function as signals that regulate food intake at the peripheral and/or central nervous system levels. Peripherally, lactate inhibits ghrelin secretion, while IL-6 increases GLP-1 secretion. In the center for regulating food intake, lactate, IL-6, leptin, and adiponectin act by inhibiting the release of orexigenic neuropeptides (NPY/AgRP) and increasing the release of anorexigenic neuropeptides (POMC). This review highlighted the role of physical exercise in overcoming obesity through suppression of food intake mediated by hormones and myokine changes that play a role in regulating food intake either in the periphery or directly in the central nervous system.

Prolactin-Releasing Peptide, a Peptide with an Improper Name, but Proper Biological Activity for Obesity, Type-2 Diabetes, and Alzheimer's Disease Treatment

Obesity is an escalating epidemic, but an effective non-invasive therapy is still scarce. For the obesity treatment, anorexigenic neuropeptides represent promising tools, but their delivery from the periphery to the brain is complicated because peptides have a low stability and limited ability to cross the blood-brain barrier. Recently discovered anorexigenic neuropeptides, such as prolactin-releasing peptide, represent new trends in development of anti-obesity agents. They are released and acting directly in brain areas regulating food intake, but generally do not cross the blood-brain barrier if administered peripherally. We succeeded to design stable palmitoylated analogs of this neuropeptide with a prolonged acute anorexigenic effect after peripheral administration as shown in mice and rats. Repeated peripheral administration of the lipidized prolactin-releasing peptide analogs resulted in long-lasting anti-obesity and antidiabetic effects in rodent models of diet-induced obesity and insulin resistance. We proved that lipidation might be an effective way to transmit the desired effect to the central nervous system after peripheral administration, for a potential treatment of obesity and related complications such as type-2 diabetes. Besides the advanced age, type-2 diabetes and obesity were shown to be risk factors for Alzheimer's disease; therefore, compounds with glucose-lowering and/or anorexigenic properties were proposed to be neuroprotective. In our group, we studied a possible crosstalk between obesity, type-2 diabetes and Alzheimer's-like pathology. We also investigated if our novel palmitoylated analogs of prolactin-releasing peptide could have beneficial effect on neurodegeneration in several mouse models of Alzheimer's-like pathology and their age-matched wild type controls. We demonstrated that these lipidized analogs are potentially neuroprotective substances improving spatial memory, neurogenesis, synaptogenesis and attenuating neuroinflammation and two hallmarks of Alzheimer's disease, i.e., tau hyper-phosphorylation and β-amyloid plaques in different mouse models of Alzheimer's-like neurodegeneration.

Body weight gain and control: beneficial effect of extra virgin olive oil versus corn oil in an experimental model of mammary cancer

Obesity is a known risk factor for breast cancer, the most common malignancy among women worldwide. We have previously described different effects of high-fat diets on mammary experimental carcinogenesis. In this work, we analyzed the animal growth data obtained in six experimental assays, in healthy and carcinogen-induced rats undergoing different dietary interventions. The animals were fed with three experimental diets administered at different periods of development: a control low-fat diet, and two isocaloric high-fat diets (rich in corn oil or in extravirgin olive oil -EVOO-). Weekly weight throughout the development of 818 animals have been compiled and reanalyzed using adjusted mathematical models. Molecular mechanisms have been investigated: ethanolamides in small intestine, neuropeptides controlling satiety in hypothalamus, and proteins controlling lipid metabolism in adipose and mammary tissues. The results indicated that the effect of diets depended on type of lipid, timing of intervention and health status. The high corn oil diet, but not the high EVOO diet, increased body weight and mass, especially if administered from weaning, in healthy animals and in those that received a moderate dose of carcinogen. The potential protective effect of EVOO on weight maintenance may be related to anorexigenic neuropeptides such as oxytocin and lipolysis/deposition balance in adipose tissue (increasing phospho-PKA, HSL, MGL and decreasing FAS). In animals with cancer, body weight gain was related to the severity of the disease. Taken together, our results suggest that EVOO has a beneficial effect on body weight maintenance in both health and cancer.

Phase-shifting the circadian glucocorticoid profile induces disordered feeding behaviour by dysregulating hypothalamic neuropeptide gene expression

Here we demonstrate, in rodents, how the timing of feeding behaviour becomes disordered when circulating glucocorticoid rhythms are dissociated from lighting cues; a phenomenon most commonly associated with shift-work and transmeridian travel ‘jetlag’. Adrenalectomized rats are infused with physiological patterns of corticosterone modelled on the endogenous adrenal secretory profile, either in-phase or out-of-phase with lighting cues. For the in-phase group, food intake is significantly greater during the rats’ active period compared to their inactive period; a feeding pattern similar to adrenal-intact control rats. In contrast, the feeding pattern of the out-of-phase group is significantly dysregulated. Consistent with a direct hypothalamic modulation of feeding behaviour, this altered timing is accompanied by dysregulated timing of anorexigenic and orexigenic neuropeptide gene expression. For Neuropeptide Y (Npy), we report a glucocorticoid-dependent direct transcriptional regulation mechanism mediated by the glucocorticoid receptor (GR). Taken together, our data highlight the adverse behavioural outcomes that can arise when two circadian systems have anti-phasic cues, in this case impacting on the glucocorticoid-regulation of a process as fundamental to health as feeding behaviour. Our findings further highlight the need for development of rational approaches in the prevention of metabolic dysfunction in circadian-disrupting activities such as transmeridian travel and shift-work.

Obesity wars: hypothalamic sEVs a new hope.

There are currently several pharmacological therapies available for the treatment of obesity, targeting both the central nervous system (CNS) and peripheral tissues. In recent years, small extracellular vesicles (sEVs) have been shown to be involved in many pathophysiological conditions. Because of their special nanosized structure and contents, sEVs can activate receptors and trigger intracellular pathways in recipient cells. Notably, in addition to transferring molecules between cells, sEVs can also alter their phenotypic characteristics. The purpose of this review is to discuss how sEVs can be used as a CNS-targeted strategy for treating obesity. Furthermore, we will evaluate current findings, such as the sEV-mediated targeting of hypothalamic AMP-activated protein kinase (AMPK), and discuss how they can be translated into clinical application.

Dietary Fat Modulation of Gut Microbiota and Impact on Regulatory Pathways Controlling Food Intake.

Obesity is a multifactorial disease that continues to increase in prevalence worldwide. Emerging evidence has shown that the development of obesity may be influenced by taxonomic shifts in gut microbiota in response to the consumption of dietary fats. Further, these alterations in gut microbiota have been shown to promote important changes in satiation signals including gut hormones (leptin, ghrelin, GLP-1, peptide YY and CCK) and orexigenic and anorexigenic neuropeptides (AgRP, NPY, POMC, CART) that influence hyperphagia and therefore obesity. In this review, we highlight mechanisms by which gut microbiota can influence these satiation signals both locally in the gastrointestinal tract and via microbiota-gut-brain communication. Then, we describe the effects of dietary interventions and associated changes in gut microbiota on satiety signals through microbiota-dependent mechanisms. Lastly, we present microbiota optimizing therapies including prebiotics, probiotics, synbiotics and weight loss surgery that can help restore beneficial gut microbiota by enhancing satiety signals to reduce hyperphagia and subsequent obesity. Overall, a better understanding of the mechanisms by which dietary fats induce taxonomical shifts in gut microbiota and their impact on satiation signaling pathways will help develop more targeted therapeutic interventions in delaying the onset of obesity and in furthering its treatment.

GPR160 is not a receptor of anorexigenic cocaine- and amphetamine-regulated transcript peptide

Cocaine- and amphetamine-regulated transcript peptide (CARTp) is an anorexigenic neuropeptide whose receptor is undisclosed. Previously, we reported the specific binding of CART(61–102) to pheochromocytoma PC12 cells, where CART(61–102) affinity and the number of binding sites per cell corresponded to ligand-receptor binding. Recently, Yosten et al. designated orphan GPR160 as the CARTp receptor, because the GPR160 antibody abolished neuropathic pain and anorexigenic effects induced by CART(55–102) and exogenous CART(55–102) coimmunoprecipitated with GPR160 in KATOIII cells. As no direct evidence that CARTp is a ligand for GPR160 has been described, we decided to verify this hypothesis by testing CARTp affinity to the GPR160 receptor. We investigated the GPR160 expression in PC12 cells since it is cell line known to specifically bind CARTp. Moreover, we examined the specific CARTp binding in THP1 cells, with high endogenous GPR160 expression and GPR160-transfected cell lines U2OS and U-251 MG. In PC12 cells, the GPR160 antibody did not compete for specific binding with 125I-CART(61–102) or with 125I-CART(55–102), and GPR160 mRNA expression and GPR160 immunoreactivity were not detected. Moreover, THP1 cells did not show any 125I-CART(61–102) or 125I-CART(55–102) specific binding despite GPR160 detection by fluorescent immunocytochemistry (ICC). Finally, no 125I-CART(61–102) or 125I-CART(55–102) specific binding in the GPR160-transfected cell lines U2OS and U-251 MG, selected due to their negligible endogenous expression of GPR160, was detected, despite the detection of GPR160 by fluorescent ICC. Our binding studies clearly demonstrated that GPR160 cannot be a receptor for CARTp. Further studies are needed to identify true CARTp receptors.

Major approaches to cannabidiol in the treatment of binge eating and obesity: a systematic review

Introduction: Obesity represents a multifactorial disease that causes serious public health problems. There are more than 2.50 billion overweight and obese people in the world, and Brazil is in fifth place in the world ranking. In this context, a factor associated with eating disorders is anxiety, which affects 33.7% of the general population. In this sense, cannabidiol (CBD) was identified 50 years ago and has effects that can change mood, sensation, perception, tension, appetite, and pain. Also, CBD showed anxiolytic, antipsychotic, neuroprotective, anti-inflammatory, and antiemetic properties. Objective: It was to analyze, through a systematic review, the main considerations and results in animal and human models of the use of cannabidiol in anxiety and obesity. Methods: The model followed for the systematic review was PRISMA. The search strategy was performed in PubMed, Embase, Ovid and Cochrane Library, Web Of Science, Science Direct Journals (Elsevier), Scopus (Elsevier), and OneFile (Gale) databases. Results: In the context of anxiety and binge eating and the consequent increase in the incidence of obese people, the activation of CB1 receptors improves feeding, modulating the activity of hypothalamic neurons and, subsequently, the release of orexigenic and anorexigenic neuropeptides. Thus, in obesity, the endocannabinoid system (ECS) is generally down-regulated in central and peripheral tissues, as indicated by high and/or overexpression of the CB1 receptor. Therefore, CBD is beneficial for anxiety-related disorders. Thus, CBD has been shown to have anxiolytic, antipsychotic, and neuroprotective properties. Conclusion: Growing evidence indicates that CBD acts as an antipsychotic and anxiolytic, and several reports suggest neuroprotective effects. Furthermore, CBD attenuates the harmful effects of trans-Δ9-tetrahydrocannabinol, both acutely and chronically, including psychotogenic, anxiogenic, and deleterious cognitive effects. This suggests that CBD may improve the disease trajectory of individuals with early psychosis and cannabis misuse in particular.

Effects of Lactobacillus acidophilus administration to anorexigenic neuropeptides and some biochemical parameters on rats fed with a high-fat diet

AimOne of the rapidly rising global public health concern is obesity. Over the past three decades, the prevalence of obesity has doubled/tripled in several nations around the world, most likely as a result of urbanization, sedentary lifestyles, and increased intake of high-calorie processed foods. In this study, it was aimed to investigate the effects of Lactobacillus acidophilus administration on rats exposed to high-fat diet experimentally on anorexigenic peptides in the brain and some biochemical parameters in the serum. MethodsIn the study, 4 different experimental groups were formed. Group 1 was designated as the control group and fed with a standard rat chow (SD). Group 2 was designated as the high-fat diet (HFD) fed group. Group 3 fed with SD and L. acidophilus probiotic administered. Group 4 fed with HFD and L. acidophilus probiotic administered. At the end of the experiment, leptin, serotonin, glucagon-like peptide-1 (GLP-1) levels were measured in the brain tissue and serum. Glucose, total cholesterol (TC), triglyceride (TG), total protein (TP), albumin, uric acid, aspartate transaminase (AST), alanine aminotransferase (ALT) levels were determined in the serum. ResultsAt the end of the study, it was found that there was an increase in body weight and body mass index in Group 2 compared to Group 1. It was determined that the levels of AST, ALT, TG, TC, glucose, leptin in the serum were significantly high (P < 0.05). The levels of GLP-1 and serotonin in the serum and in the brain were significantly low (P < 0.05). There was a significant decrease in TG and TC in Groups 3 and 4 compared to Group 2 (P < 0.05). The leptin hormone levels in serum and brain were significantly higher in Group 2 than in other groups (P < 0.05). GLP-1 and serotonin levels were found to be significantly low (P < 0.05). The leptin levels in the serum of Groups 3 and 4 decreased significantly compared to Group 2 (P < 0.05). ConclusionIt was found that probiotic supplementation in high-fat diet had positive effects on anorexigenic peptides. It was concluded that L. acidophilus probiotic can be recommended as a food supplement in the treatment of obesity.

Microbes, oxytocin and stress: Converging players regulating eating behavior.

Oxytocin is a peptide-hormone extensively studied for its multifaceted biological functions and has recently gained attention for its role in eating behavior, through its action as an anorexigenic neuropeptide. Moreover, the gut microbiota is involved in oxytocinergic signaling through the brain-gut axis, specifically in the regulation of social behavior. The gut microbiota is also implicated in appetite regulation and is postulated to play a role in central regulation of hedonic eating. In this review, we provide an overview on oxytocin and its individual links with the microbiome, the homeostatic and non-homeostatic regulation of eating behavior as well as social behavior and stress.

AgRP Neuron-Specific Ablation Represses Appetite, Energy Intake, and Somatic Growth in Larval Zebrafish

Neuronal circuits regulating appetite are dominated by arcuate nucleus neurons, which include appetite-promoting and -suppressing neurons that release the orexigenic neuropeptide agouti-related protein (AgRP) and anorexigenic neuropeptide pro-opiomelanocortin, respectively, to compete for melanocortin receptors to modulate feeding behavior. In this study, we expressed novel agrp promoters, including different lengths of the 5' flanking regions of the agrp gene (4749 bp) in the zebrafish genome. We used the agrp promoter to derive the enhanced green fluorescent protein (EGFP)-nitroreductase (NTR) fusion protein, allowing expression of the green fluorescence signal in the AgRP neurons. Then, we treated the transgenic zebrafish AgRP4.7NTR (Tg [agrp-EGFP-NTR]) with metronidazole to ablate the AgRP neurons in the larvae stage and observed a decline in their appetite and growth. The expression of most orexigenic and growth hormone/insulin-like growth factor axis genes decreased, whereas that of several anorexigenic genes increased. Our findings demonstrate that AgRP is a critical regulator of neuronal signaling for zebrafish appetite and energy intake control. Thus, AgRP4.7NTR can be used as a drug-screening platform for therapeutic targets to treat human appetite disorders, including obesity. Furthermore, the unique agrp promoter we identified can be a powerful tool for research on AgRP neurons, especially AgRP neuron-mediated pathways in the hypothalamus, and appetite.

Search for lipidized PrRP analogs with strong anorexigenic effect: In vitro and in vivo studies

Prolactin-releasing peptide (PrRP) is an anorexigenic neuropeptide that attenuates food intake and increases energy expenditure. We designed three series of new lipidized PrRP31 analogs of different lengths of fatty acids attached at amino acids 1 or 11 directly or via linkers, part of them acetylated at the N-terminus and/or modified with dichlorophenylalanine (PheCl2) at the C-terminus. We tested their affinity for and activation of signaling pathways relevant to receptors GPR10, NPFF-R2, and NPFF-R1, effect on food intake in fasted or freely fed mice and rats, and stability in rat plasma. We aimed to select a strong dual GPR10/NPFF-R2 agonist whose affinity for NPFF-1 was not enhanced. The selected potent analog was then tested for body weight-lowering potency after chronic administration in mice with diet-induced obesity. PrRP31 analogs lipidized by monocarboxylic fatty acids showed strong dual affinity for both GPR10 and NPFF-R2 and activated MAPK/ERK1/2, Akt and CREB in cells overexpressing GPR10 and NPFF-R2. The selected analog stabilized at N- and C-termini and palmitoylated through the TTDS linker to Lys11 is a powerful dual agonist GPR10/NPFF-R2 at not enhanced affinity for NPFF-R1. It showed strong anti-obesity properties in mice with diet-induced obesity and became a potential compound for further studies.

Does NUCB2/Nesfatin-1 Influence Eating Behaviors in Obese Patients with Binge Eating Disorder? Toward a Neurobiological Pathway.

Nesfatin-1 is a new anorexigenic neuropeptide involved in the regulation of hunger/satiety, eating, and affective disorders. We aimed to investigate nesfatin-1 secretion in vitro, in murine adipose cells, and in human adipose fat samples, as well as to assess the link between circulating nesfatin-1 levels, NUCB2 and Fat Mass and Obesity Gene (FTO) polymorphisms, BMI, Eating Disorders (EDs), and pathological behaviors. Nesfatin-1 secretion was evaluated both in normoxic fully differentiated 3T3-L1 mouse adipocytes and after incubation under hypoxic conditions for 24 h. Omental Visceral Adipose tissue (VAT) specimens of 11 obese subjects, and nesfatin-1 serum levels' evaluation, eating behaviors, NUCB2 rs757081, and FTO rs9939609 polymorphisms of 71 outpatients seeking treatment for EDs with different Body Mass Index (BMI) were studied. Significantly higher levels of nesfatin-1 were detected in hypoxic 3T3-L1 cultured adipocytes compared to normoxic ones. Nesfatin-1 was highly detectable in the VAT of obese compared to normal-weight subjects. Nesfatin-1 serum levels did not vary according to BMI, sex, and EDs diagnosis, but correlations with grazing; emotional, sweet, and binge eating; hyperphagia; social eating; childhood obesity were evident. Obese subjects with CG genotype NUCB2 rs757081 and AT genotype FTO rs9939609 polymorphisms had higher nesfatin-1 levels. It could represent a new biomarker of EDs comorbidity among obese patients.