Localization of nesfatin-1 neurons in the mouse brain and functional implication

Association among nesfatin-1, obesity category, presence of obesity-related complications, and eating patterns in patients with obesity: Results of a single endocrine centre observational study

Since its discovery, nesfatin-1 (N1) has been recognised as an anorexigenic agent potentially related to obesity pathogenesis and development, including its modulatory effect on the brain's reward system and eating behaviours. As the results from human studies examining the relation between N1 serum levels, body mass index (BMI), and metabolic status are scarce and inconclusive, we aimed to investigate the association between serum N1 levels and obesity categories, obesity-related complications, and disturbed eating behaviour. We studied 110 patients with obesity divided into obesity categories according to their BMI and metabolic status. N1 was measured in a fasting state (N10) and 2 h after a glucose load (N12) and correlated with anthropometric measurements, serum analysis, and the presence of selected obesity-related complications. Neither N10 nor N12 correlated significantly with obesity; however, N10 tended to be high in patients with a high BMI. A positive correlation was observed among N12, fat-free mass (p = 0.022), and muscle mass (p = 0.02). We found positive correlations between N10 and N12 with aspartate aminotransferase (p = 0.012 and p = 0.022, respectively) and alanine aminotransferase (p = 0.027 and p = 0.006, respectively). Patients with dyslipidaemia had significantly higher N10 (p = 0.03) and N12 (p = 0.049) levels. Neither N10 nor N12 correlated significantly with disturbed eating behaviour; however, low N10 levels were associated with a hedonic eating pattern (p = 0.03). N1 may be involved in the pathogenesis of obesity and obesity-related complications; however, owing to the complex mechanisms of its secretion and action, further clinical and experimental research is needed.

Neuroanatomical mapping of spexin and nesfatin-1-expressing neurons in the human brainstem

Neuropeptides are involved in numerous brain activities being able to control a wide spectrum of physiological functions. In recent years, a number of novel pleiotropic regulatory peptides have been discovered in animal brain structures. The purpose of this descriptive neurochemical investigation was to detect the possible expression of the novel multifunctional neuropeptides spexin (SPX) and nesfatin-1 within the human brainstem. Using immunohistochemical and fluorescence techniques, neuroanatomical analysis of the SPX and nesfatin-1 expression and distribution was performed in selected sections of the human midbrain and medulla oblongata. The presence of SPX-positive neurons in the human brainstem was revealed for the first time and previous reports on the expression of nesfatin-1 were additionally confirmed. The research results suggest that SPX and nesfatin-1 are new regulatory neuropeptides of the human brainstem potentially involved in the regulation of key autonomic activities of this brain region.

Nesfatin-1 is involved in hyperbaric oxygen-mediated therapeutic effects in high fat diet-induced hyperphagia in mice

Obesity is a worldwide health issue. Effective and safe methods for obesity management are highly desirable. In the current study, hyperbaric oxygen (HBO) treatment was investigated as a potential treatment against obesity-associated hyperphagia and hyperenergy intake. Diet induced obesity (DIO) mice model was established with high fat diet (HFD) feeding, HBO was then co-administered. Food and energy intake were assessed with nocturnal food intake assay. Immunohistochemistry for c-Fos was performed for neuronal activation in arcuate nucleus (ARC), paraventricular nucleus of hypothalamus (PVN) and lateral parabrachial nucleus (LPBN) of brain. Additionally, enzyme-linked immunosorbent assay (ELISA) in serum and immunofluorescence in LPBN were performed. Results indicated that HBO co-treatment effectively decreased food and energy intake in DIO mice, reverted the abnormal neuronal activation in the ARC and PVN, and enhanced both peripheral and central nesfatin-1 peptide levels without affecting serum leptin levels. While SHU9119 microinjection in LPBN effectively abolished the beneficial effects of HBO on body weight, visceral fat, nocturnal feeding and energy intake in DIO mice. In conclusion, HBO treatment could effectively protect against HFD-induced increase of food and energy intake, which is associated with its central effects against abnormal neuronal activation in ARC and PVN and enhanced peptide levels of nesfatin-1 both centrally and peripherally. The melanocortin system downstream of nesfatin-1 may exert a potential effect in this process.

Nesfatin-1: A Novel Diagnostic and Prognostic Biomarker in Digestive Diseases

Nesfatin-1, deriving from a precursor protein, NUCB2, is a newly discovered molecule with anti-apoptotic, anti-inflammatory, antioxidant, and anorexigenic effects. It was initially identified in the central nervous system (CNS) and received increasing interest due to its energy-regulating properties. However, research showed that nesfatin-1 is also expressed in peripheral tissues, including the digestive system. The aim of this review is to give a résumé of the present state of knowledge regarding its structure, immunolocalization, and potential implications in diseases with inflammatory components. The main objective was to focus on its clinical importance as a diagnostic biomarker and potential therapeutic molecule in a variety of disorders, among which digestive disorders were of particular interest. Previous studies have shown that nesfatin-1 regulates the balance between pro- and antioxidant agents, which makes nesfatin-1 a promising therapeutic agent. Further in-depth research regarding the underlying mechanisms of action is needed for a better understanding of its effects.

Electroacupuncture negatively regulates the Nesfatin-1/ERK/CREB pathway to alleviate HPA axis hyperactivity and anxiety-like behaviors caused by surgical trauma

BACKGROUND

Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis constitutes a pivotal response by surgical trauma, manifesting as a critical aspect of the acute stress reaction. This hyperactivity resulted in adverse surgical outcomes and is often associated with increased postoperative anxiety. Increased evidence suggests that Nesfatin-1 plays a crucial role in stress responses and stress-related psychiatric disorders. Electroacupuncture (EA) is widely used to alleviate stress responses and anxiety, although its mechanism of action remains unclear. This study aimed to assess the mechanisms by which hypothalamic Nesfatin-1 contribute to the alleviation of HPA axis hyperactivity and anxiety by EA.

METHODS

Partial hepatectomy (HT) was performed to simulate surgical trauma, and EA was applied at Zusanli (ST36) and Sanyinjiao (SP6). The levels of hypothalamic Nesfatin-1, c-Fos, and corticotropin-releasing hormone (CRH) were detected, and serum adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were regarded as indicators of HPA axis activity. Anxiety levels were assessed through open field tests (OFT), elevated plus maze (EPM), and light-dark box tests (LDBT). To investigate the role of Nesfatin-1, its expression was modulated using stereotactic viral injections or plasmid transfections. Transcriptome sequencing was employed to explore the downstream signaling pathways of Nesfatin-1. Additionally, brain cannula implantation was performed to facilitate targeted drug administration.

RESULTS

Our findings demonstrated that EA reduced the hypothalamic overexpression of CRH and Nesfatin-1, as well as serum levels of ACTH and CORT. Additionally, it alleviated anxiety-like behaviors resulting from surgical trauma. We observed that overexpression of Nesfatin-1 in the hypothalamic paraventricular nucleus (PVN) triggered hyperactivity of the HPA axis and anxiety. Conversely, knocking down Nesfatin-1 in the PVN reversed these effects caused by surgical trauma. Transcriptome sequencing identified the extracellular regulated protein kinases (ERK)/cAMP-response element binding protein (CREB) pathway as a key mediator in the impacts of surgical trauma and EA on the hypothalamus. Both in vivo and in vitro studies showed that overexpression of Nesfatin-1 activated the ERK/CREB pathway. Furthermore, administering ERK or CREB inhibitors into the PVN mitigated HPA axis hyperactivity and anxiety-like behaviors induced by surgical trauma. Finally, EA was observed to decrease the phosphorylation levels of ERK and CREB in the PVN.

CONCLUSION

EA alleviates HPA axis hyperactivity and anxiety-like behaviors caused by surgical trauma through inhibition of Nesfatin-1/ERK/CREB pathway in the hypothalamus.

Nesfatin-1 and nesfatin-1-like peptide attenuate hepatocyte lipid accumulation and nucleobindin-1 disruption modulates lipid metabolic pathways

Nesfatin-1 (NESF-1) has been shown to modulate lipid metabolism. We have identified a nesfatin-1-like-peptide (NLP) processed from a related precursor nucleobindin 1 (NUCB1). Here we determined if NLP, like NESF-1, regulates lipid accumulation in vitro, and tested if the disruption of nucb1 gene affects hepatic lipid metabolism genes in mice. Hepatocytes (HepG2/C3A cells) express NLP and NESF-1 and both peptides significantly reduced lipogenic enzyme mRNAs and enhanced beta-oxidation enzyme mRNAs. Lipid contents in oleic acid induced HepG2/C3A cells were attenuated by NESF-1 and NLP. The inhibitory effect on cellular lipid content was blocked by compound C, an inhibitor of AMPK. The disruption of nucb1 gene affected lipid metabolism-related enzyme mRNAs, endogenous nucb2 mRNA and AMPK phosphorylation. The lipid-lowering effects identified here highlights the potential of nucleobindins and peptides processed from them to address lipid disorders, and its possible benefits in metabolic disease management.

Central thromboxane A2, prostaglandin F2α, prostaglandin E, and prostaglandin D contribute to the cardiovascular effects elicited by nesfatin-1

Background/aim

Our recent study revealed that the expression of lipoxygenase (LOX) and cyclooxygenase (COX) enzymes in the hypothalamus is activated by nesfatin-1, leading to the liberation of leukotrienes and prostaglandins (PG), respectively. Moreover, our prior report explained that intracerebroventricular (ICV) nesfatin-1 treatment triggers cardiovascular responses mediated by central LOX and COX enzymes. Building upon our prior reports, the present investigation sought to clarify the role of cardiovascularly active central COX products, such as thromboxane (TX) A2, PGF2α, PGE, and PGD, in orchestrating nesfatin-1-evoked reactions in mean arterial pressure (MAP) and heart rate (HR).

Materials and methods

The Sprague Dawley rats, which had guide cannula in the lateral ventricle for intracerebroventricular (ICV) injections and catheter in arteria femoralis for monitoring MAP and HR, were underwent central pretreatment with furegrelate (the TXA2 synthase inhibitor), PGF2α-dimethylamine (PGF2α-DA, the PGF2α receptor antagonist), or AH6809 (the PGE and PGD receptor antagonist), 5 min prior to ICV nesfatin-1 administration. The cardiovascular parameters were observed and recorded for 60 min posttreatment.

Results

Nesfatin-1 induced cardiovascular responses in rats leading to pressor effect in MAP, and tachycardia following bradycardia in HR. Interestingly, ICV furegrelate, PGF2α-DA, or AH6809 pretreatment partially mitigated the cardiovascular effects revealed by nesfatin-1.

Conclusion

The findings illuminate the role of nesfatin-1 in modulating MAP and HR through the central activation of specifically TXA2, PGF2α, PGE, and PGD from COX metabolites. Additionally, the study may also suggest the potential involvement of other central COX or LOX metabolites beyond these COX metabolites in mediating the cardiovascular effects produced by nesfatin-1.

Influence of NUCB/Nesfatin-1 Polymorphism on Treatment Response to Naltrexone/Bupropion SR in Binge Eating Disorder and Obesity

Background and Objectives: The NUCB2 gene and its polymorphisms were identified as novel players in the regulation of food intake, potentially leading to obesity (OBE) and altered eating behaviors. Naltrexone/bupropion SR (NB) showed good efficacy and tolerability for treating OBE and altered eating behaviors associated with binge eating disorder (BED). This prospective study investigates the influence of NUCB2 gene polymorphism on NB treatment response in OBE and BED. Materials and Methods: Body mass index (BMI), eating (EDE-Q, BES, NEQ, GQ, Y-FAS 2.0) and general psychopathology (BDI, STAI-S) were evaluated at baseline (t0) and after 16 weeks (t1) of NB treatment in patients with OBE and BED (Group 1; N = 22) vs. patients with OBE without BED (Group 2; N = 20). Differences were evaluated according to the rs757081 NUCB2 gene polymorphism. Results: NUCB2 polymorphism was equally distributed between groups. Although weight at t0 was higher in Group 1, weight loss was similar at t1 in both groups. BMI was not influenced by NUCB2 polymorphism. In Group 1, the CG-genotype reported significant improvement in eating psychopathology while the GG-genotype reported improvement only for FA. No differences were observed in Group 2. Conclusions: Patients diagnosed with BED and treated with NB exhibited a more favorable treatment response within the CG-genotype of the NUCB2 polymorphism.

The Relation between Plasma Nesfatin-1 Levels and Aggressive Behavior in Pit Bull Dogs

Aggression is a prevalent and concerning behavioral issue in dogs. Pit Bull dogs, known for their high levels of aggression, are recognized as a focus of concern in society. In our study, we aimed to investigate the behavioral characteristics of Pit Bull dogs and explore the potential roles of peptides involved in the neurobiology of aggression. Initially, female, and male dogs underwent aggression tests, and their aggression levels were categorized. Plasma nesfatin-1, serotonin, oxytocin, and dopamine levels were quantified using ELISA, with blood samples collected after a 24 h fasting period and 2 h post-refeeding. Our findings indicate that aggression in Pit Bull dogs correlates with decreased plasma nesfatin-1, serotonin, and oxytocin levels, while dopamine levels increase. The study's findings indicate that fasted dogs exhibited lower plasma levels of nesfatin-1, serotonin, and dopamine, while plasma oxytocin levels were higher. Furthermore, while the research findings do not suggest a significant relationship between the severity of aggression and the gender of the dog, male Pit Bull breeds appear to have higher plasma nesfatin-1 and serotonin levels compared to their female counterparts. The study's findings demonstrate that nesfatin-1, serotonin, oxytocin, and dopamine play pivotal roles in Pit Bull dogs' aggression, indicating potential interactions among these neuropeptides at the central nervous system level.

Effects of physical activity and exercise on Nucleobindin-2 gene expression and Nesfatin-1 concentration: A rapid review

The aim of this rapid review is to examine the research evidence that presents the effects of physical activity and exercise on Nucleobindin-2 (NUCB2) gene expression and Nesfatin-1 concentration. Five databases (PubMed, Science Direct, Springer, Wiley, and Google Scholar) were searched for eligible studies from the earliest available date to August 2023. In human studies, Nesfatin-1 concentration either remains unchanged or increases after exercise training. It appears that higher exercise intensity and longer duration of training accentuate the increase of blood Nesfatin-1 concentration. The few human studies that have examined the acute response of exercise on Nesfatin-1 concentration from blood draws show conflicting results. There is a severe lack of biopsy studies in humans which warrants attention. All published animal studies have used the mouse model. The majority show that regular exercise training increases tissue NUCB2/Nesfatin-1. In some animal studies, where the effects of exercise on tissue Nesfatin-1 concentration has been seen as significant, there has been no significant effect of exercise on plasma Nesfatin-1 concentration. All animal studies evaluated the effect of endurance training except one which used resistance training. No animal studies have investigated the effects of acute exercise, which warrants investigation. In conclusion, human and animal studies have shown that physical training can increase NUCB2/Nesfatin-1, but research evidence examining the effect of acute exercise is in its infancy. In addition, future comparative studies are needed to compare the effects of different training protocols on NUCB2/Nesfatin-1 in humans and animals.

Nesfatin-1 regulates steroidogenesis in mouse Leydig cells

Nesfatin-1 is a polypeptide hormone known to regulate appetite and energy metabolism and is derived from the precursor protein nucleobindin 2 (NUCB2). Recent studies have shown that nesfatin-1 is expressed in many peripheral tissues in mice, including the reproductive organs. However, its function and regulation in the testis remain unknown. In this study, we investigated the expression of Nucb2 mRNA and nesfatin-1 protein in mouse Leydig cells and the Leydig cell line, TM3 cells. We also examined whether Nucb2 mRNA expression is regulated by gonadotropins and whether exogenous nesfatin-1 affects steroidogenesis in primary Leydig cells isolated from the testis and TM3 cells. We found that Nucb2 mRNA and nesfatin-1 protein were present in primary Leydig cells and TM3 cells, and nesfatin-1 binding sites were also found in both cell types. Nucb2 mRNA expression in testis, primary Leydig cells, and TM3 cells was increased after treatment with pregnant mare's serum gonadotropin and human chorionic gonadotropin. After nesfatin-1 treatment, the expression of steroidogenesis-related enzyme genes Cyp17a1 and Hsd3b was upregulated in primary Leydig cells and TM3 cells. Our results suggest that NUCB2/nesfatin-1 expression in mouse Leydig cells may be regulated through the hypothalamic-pituitary-gonadal axis and that nesfatin-1 produced by Leydig cells may locally regulate steroidogenesis in an autocrine manner. This study provides insight into the regulation of NUCB2/nesfatin-1 expression in Leydig cells and the effect of nesfatin-1 on steroidogenesis, which may have implications for male reproductive health.

Role of brain NUCB2/nesfatin-1 in stress and stress-related gastrointestinal disorders

Since the discovery of NUCB2/nesfatin-1 as a novel anorexigenic factor, the expanding function of this peptide has been elucidated in recent years. Increasing evidence suggests that NUCB2/nesfatin-1 is also involved in the regulation of stress and stress-related gastrointestinal disorders. Therefore, we investigated the relationship between NUCB2/nesfatin-1, stress and stress-related gastrointestinal disorders and summarized the results of these studies. Different stressors and duration of stress activate different NUCB2/nesfatin-1-associated brain regions and have different effects on serum corticosterone levels. Central and peripheral NUCB2/nesfatin-1 mediates stress-related gastrointestinal disorders but appears to be protective against inflammatory bowel disease. NUCB2/nesfatin-1 plays an important role in mediating the brain-gut crosstalk, but precise clarification is still needed to gain more insight into these complex relationships.

Neuropeptides Modulate Feeding via the Dopamine Reward Pathway

Dopamine (DA) is a catecholamine neurotransmitter widely distributed in the central nervous system. It participates in various physiological functions, such as feeding, anxiety, fear, sleeping and arousal. The regulation of feeding is exceptionally complex, involving energy homeostasis and reward motivation. The reward system comprises the ventral tegmental area (VTA), nucleus accumbens (NAc), hypothalamus, and limbic system. This paper illustrates the detailed mechanisms of eight typical orexigenic and anorexic neuropeptides that regulate food intake through the reward system. According to recent literature, neuropeptides released from the hypothalamus and other brain regions regulate reward feeding predominantly through dopaminergic neurons projecting from the VTA to the NAc. In addition, their effect on the dopaminergic system is mediated by the prefrontal cortex, paraventricular thalamus, laterodorsal tegmental area, amygdala, and complex neural circuits. Research on neuropeptides involved in reward feeding can help identify more targets to treat diseases with metabolic disorders, such as obesity.

Expression of phoenixin-14 and nesfatin-1 in the hypothalamo-pituitary-gonadal axis in the phases of the estrous cycle

Phoenixin-14 (PNX-14) and nucleobindin 2 (NUCB2)/nesfatin-1 are regulatory neuropeptides expressed in the hypothalamus. These neuropeptides can be effective in hormonal regulation of the hypothalamo-pituitary-gonadal (HPG) axis and reproductive functions. In the present study, the distribution of PNX-14 and NUCB2/nesfatin-1 in the hypothalamus, pituitary, ovary, and uterus tissues during the phases of the estrous cycle in female rats was investigated. Eighteen Wistar Albino rats determined among animals showing regular estrous cycle by vaginal smear method were divided into three groups: proestrus (Group I), estrus (Group II) and diestrus (Group III). Serum gonadotropin-releasing hormone (GnRH), plasma PNX-14, and NUCB2/nesfatin-1 concentrations were the highest, moderate, and lowest in estrus, diestrus, and proestrus phases, respectively. PNX-14 immunoreactivity in the supraoptic and arcuate nuclei of the hypothalamus and NUCB2/nesfatin-1 immunoreactivity in the paraventricular nuclei were particularly evident in the estrus phase. These neuropeptide immunoreactivities were decreased in different cells of anterior pituitary during proestrus compared with those during estrus and diestrus. PNX-14 immunoreactivity in the ovary, especially during the estrus phase, was diffuse and intense in the granulosa and luteal cells and oocytes, and it was few and weak in theca cells. In addition, NUCB2/nesfatin-1 immunoreactivity was abundant and strong in granulosa and luteal cells, theca and interstitial cells, and oocytes during estrus. In the estrus phase, PNX-14 immunoreactivity was strong in the glandular epithelial cells and stromal cells of the endometrium, also NUCB2/nesfatin-1 immunoreactivity was strong in the epithelial and glandular epithelial cells. As a result, when the estrous cycle was evaluated, it was concluded that the changes in the distribution of PNX-14 and NUCB2/nesfatin-1 at all phases were related to GnRH and that these neuropeptides showed the highest immunoreactivity especially in the HPG axis and uterus tissues of estrus rats.

NUCB2/nesfatin-1 suppresses the acrosome reaction in sperm within the mouse epididymis

Nesfatin-1, a polypeptide hormone derived from the nucleobindin 2 (NUCB2) precursor protein, is known to regulate appetite and energy metabolism. Recent studies have also shown that NUCB2/nesfatin-1 is expressed in the reproductive organs of mice. However, the expression and potential role of NUCB2/nesfatin-1 in the mouse epididymis remain unclear. Therefore, we investigated the expression of NUCB2/nesfatin-1 in the mouse epididymis and its potential function. NUCB2/nesfatin-1 was detected in the epididymis by qRT-PCR and western blotting, and high expression levels were observed in epididymal epithelial cells by immunohistochemical staining. Pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) injections significantly increased NUCB2/nesfatin-1 expression in the epididymis. After castration, NUCB2/nesfatin-1 expression in the epididymis decreased, but was significantly increased by testosterone injection. Nesfatin-1-binding sites were found in the middle piece of testicular sperm, but were scarcely detected in the sperm head. By contrast, nesfatin-1 binding sites were identified on the sperm head within the epididymis. Furthermore, nesfatin-1 treatment inhibited the acrosome reaction in epididymal sperm. These results suggest that the nesfatin-1 protein produced in the epididymis binds to nesfatin-1 binding sites on the sperm head and plays a role in suppressing the acrosome reaction before ejaculation.

Nesfatin-1 in Human Milk and Its Association with Infant Anthropometry

Breastfed infants have different growth patterns to formula-fed infants and are less likely to develop obesity later in life. Nesfatin-1 is an anorexigenic adipokine that was discovered in human milk more than a decade ago, and its role in infant appetite regulation is not clear. Our aim was to describe nesfatin-1 levels in human milk collected 3-4 months postpartum, associations with infant anthropometry, and factors (maternal pre-pregnancy body mass index (mBMI), high weight gain during pregnancy, milk fat, and energy content) possibly influencing nesfatin-1 levels. We hypothesized that nesfatin-1 levels in mother's milk would differ for infants that were large (high weight-for-age Z-score (WAZ)) or small (low WAZ) at the time of milk sample collection. We used enzyme-linked immunosorbent assay to detect the nesfatin-1 concentration in milk samples from mothers to high WAZ (n = 50) and low WAZ (n = 50) infants. We investigated associations between nesfatin-1 levels and infant anthropometry at 3-4 months of age and growth since birth, using linear regression adjusted for mBMI, birth weight, infant sex, and exclusivity of breastfeeding. We found no difference in nesfatin-1 levels between the two groups and no association with infant anthropometry, even after adjusting for potential confounders. However, high nesfatin-1 levels were correlated with low mBMI. Future research should investigate serum nesfatin-1 level in both mothers, infants and associations with growth in breastfed children.

Does one plus one always equal two? Structural differences between nesfatin-1, -2, and nesfatin-1/2

Nesfatin-1 and -2 are produced from a reaction in which the N-terminus of human Nucleobindin-2 undergoes proteolytical processing. To date, Nucleobindin-2 and/or nesfatin-1 have only been shown to act as peptide hormones. On the other hand, the purpose of nesfatin-2 remains unknown. Since Nucleobindin-2/nesfatin-1 is thought impact the control of a wide range of physiological processes, including energy homeostasis, neurodegenerative processes and carcinogenesis, its ligands/interactions deserve special studies and attention. However, there are no reports about the molecular properties of the proteolytical products of human Nucleobindin-2 in the literature. Hence, this study aimed to analyze the effect of Zn(II) and Ca(II) on human nesfatin-1, -2, and -1/2 structures. Herein, we report that human nesfatin-1 is a member of the intrinsically disordered protein family, as indicated by circular dichroism and analytical ultracentrifugation experiments. In contrast, we found that the human nesfatin-2 and nesfatin-1/2 structures were globular with intrinsically disordered regions. Under Zn(II) treatment, we observed concentration-dependent structurization and compaction of intrinsically disordered nesfatin-1 and its propensity for oligomerization, as well as destabilization of both nesfatin-2 and nesfatin-1/2. Furthermore, dissociation constants for Zn(II) binding by nesfatin-1, nesfatin-2, and nesfatin-1/2 were also reported. Moreover, structurally distinct nesfatin-1 and -2 seem to be interdependent when linked together, as indicated by the observed molecular properties of nesfatin-1/2, which in turn are not a simple sum of the properties exhibited by the former peptides. Thus, herein, we shed new light on the molecular behavior of human nesfatins, which might help to elucidate the complex function of those peptides. Video abstract.

NUCB2/nesfatin-1 is associated with severity of eating disorder symptoms in female patients with obesity

BACKGROUND

Nesfatin-1 has been described as an anorexigenic peptide. Comprehensive evidence also points towards an involvement of nesfatin-1 in the modulation of emotional pathways with a sex-specific regulation of nesfatin-1 in association with anxiety. Although the implication of nesfatin-1 in the regulation of food intake is well-established in animals, data in humans are lacking. Therefore, we investigated a possible association of circulating NUCB2/nesfatin-1 with eating disorder symptoms in female and male patients displaying a wide range of body weight.

METHODS

We enrolled 243 inpatients (177 female, 66 male) hospitalized due to anorexia nervosa (n = 66) or obesity (n = 144) or with normal weight and suffering from somatoform, adjustment, depressive or anxiety disorders (n = 33). Plasma samples (NUCB2/nesfatin-1 levels measured by ELISA) and measures of eating disorder symptoms (by EDI-2, range 0-100) were obtained within three days after admission.

RESULTS

The study population displayed a distinct prevalence of eating disorder symptoms with female patients with anorexia nervosa (+ 77.0%, p < 0.001) and obesity (+ 87.9%, p < 0.001) reported significantly higher EDI-2 scores than normal weight patients of the same sex. Accordingly, males with anorexia nervosa (+ 39.7%, p < 0.05) and obesity (+ 51.7%, p < 0.001) had significantly higher EDI-2 scores than males with normal weight. Within the same BMI group, women displayed significantly higher scores than men (+ 21.4%, p < 0.05 in patients with anorexia nervosa, + 18.8%, p < 0.001 in participants with obesity). We observed a positive correlation between NUCB2/nesfatin-1 levels and EDI-2 total scores in female patients with obesity (r = 0.285, p = 0.015), whereas no associations were found in other subgroups. A positive correlation between NUCB2/nesfatin-1 levels and BMI was only observed in the male study population (r = 0.315, p = 0.018).

CONCLUSIONS

NUCB2/nesfatin-1 plasma levels were positively associated with EDI-2 total scores in women with obesity, while no association was observable in men. The lacking association of NUCB2/nesfatin-1 and EDI-2 total scores in female patients with anorexia nervosa might be due to already low NUCB2/nesfatin-1 plasma levels. Whether NUCB2/nesfatin-1 is selectively involved in eating behavior in women with obesity will have to be further investigated.

The ins and outs of the caudal nucleus of the solitary tract: An overview of cellular populations and anatomical connections

The body and brain are in constant two-way communication. Driving this communication is a region in the lower brainstem: the dorsal vagal complex. Within the dorsal vagal complex, the caudal nucleus of the solitary tract (cNTS) is a major first stop for incoming information from the body to the brain carried by the vagus nerve. The anatomy of this region makes it ideally positioned to respond to signals of change in both emotional and bodily states. In turn, the cNTS controls the activity of regions throughout the brain that are involved in the control of both behaviour and physiology. This review is intended to help anyone with an interest in the cNTS. First, I provide an overview of the architecture of the cNTS and outline the wide range of neurotransmitters expressed in subsets of neurons in the cNTS. Next, in detail, I discuss the known inputs and outputs of the cNTS and briefly highlight what is known regarding the neurochemical makeup and function of those connections. Then, I discuss one group of cNTS neurons: glucagon-like peptide-1 (GLP-1)-expressing neurons. GLP-1 neurons serve as a good example of a group of cNTS neurons, which receive input from varied sources and have the ability to modulate both behaviour and physiology. Finally, I consider what we might learn about other cNTS neurons from our study of GLP-1 neurons and why it is important to remember that the manipulation of molecularly defined subsets of cNTS neurons is likely to affect physiology and behaviours beyond those monitored in individual experiments.

The Actions of Centrally Administered Nesfatin-1 on Emesis, Feeding, and Locomotor Activity in Suncus murinus (House Musk Shrew)

Nesfatin-1 is an anorectic peptide expressed in both peripheral tissues and brain areas involved in the regulation of feeding, emotion and emesis. The aim of the present study is to characterize the distribution of NUCB2/nesfatin-1 in Suncus murinus and to investigate the actions of nesfatin-1 to affect gastrointestinal contractility, emesis, food and water intake, and locomotor activity. The deduced amino acid sequence of S. murinus nesfatin-1 using in silico cloning showed high homology with humans and rodents. NUCB2 mRNA was detected throughout the entire brain and in the gastrointestinal tract, including the stomach and gut. Western blot analysis and immunohistochemistry confirmed the expression of nesfatin-1 protein in these regions. The NUCB2 mRNA levels in the hypothalamus, hippocampus and brainstem were significantly decreased, whereas that in the striatum were increased after 24 h starvation compared to ad libitum-fed animals (p &lt; 0.05). In in vitro studies, nesfatin-1 (0.3–1,000 pM) failed to contract or relax the isolated gastric antrum and intestinal segments. In conscious, freely moving animals, intracerebroventricular administration of nesfatin-1 (1–50 pmol) induced emesis (p &lt; 0.05) and suppressed 6-h cumulative food intake (p &lt; 0.05), without affecting the latency to feeding. Nesfatin-1 (25 pmol, i.c.v.) decreased 24-h cumulative food and water intake by 28.3 and 35.4%, respectively (p &lt; 0.01). No significant differences in locomotor activity were observed. In conclusion, NUCB2/nesfatin-1 might be a potent regulator of feeding and emesis in S. murinus. Further studies are required to elucidate the mechanism of actions of this peptide as a mediator linking the brainstem NUCB2/nesfatin-1 to forebrain system.

Interactions between nesfatin-1 and the autonomic nervous system-An overview

Nesfatin-1, an 82-amino acid polypeptide derived from the precursor protein nucleobindin-2 (NUCB2), was first discovered in 2006 in the rat hypothalamus. The effects and distribution of nesfatin-1 immunopositive neurons in the brain and spinal cord point towards a role of NUCB2/nesfatin-1 in autonomic regulation. Therefore, studies which have been conducted to investigate the interplay between nesfatin-1 and the autonomic nervous system were examined, and the outcomes of this research were summarized. NUCB2/nesfatin-1 immunoreactivity is widely distributed in autonomic centers of the brain and spinal cord in both rodents and humans. In several regions of the hypothalamus, midbrain and brainstem, nesfatin-1 modulates autonomic functions. On the other hand, the autonomic nervous system also influences the activity of nesfatin-1 neurons. Here, the vagus nerve seems to be a crucial factor in the regulation of nesfatin-1. In summary, although data here is still sparse, there is a clear interplay between nesfatin-1 and the autonomic nervous system, the precise clarification of which still requires further research to gain more insight into these complex relationships.

The involvement of the central cholinergic system in the hyperventilation effect of centrally injected nesfatin-1 in rats

We recently demonstrated that peripheral and central administration of nesfatin-1 in fasting and satiety states generate hyperventilation activity by increasing tidal volume (TV), respiratory rate (RR), and respiratory minute ventilation (RVM). The present study aimed to investigate the mediation of central cholinergic receptors effective in respiratory control in the hyperventilation activity of nesfatin-1. Besides this, we intended to determine possible changes in blood gases due to hyperventilation activity caused by nesfatin-1 and investigate the mediation of central cholinergic receptors in these changes. Intracerebroventricular (ICV) administration of nesfatin-1 revealed a hyperventilation response with an increase in TV, RR, RMV, and pO₂ and a decrease in pCO₂ in saturated Sprague Dawley rats. ICV pretreatment with the muscarinic receptor antagonist atropine partially blocked the RR, RMV, pO₂, and pCO₂ responses produced by nesfatin-1 while completely blocking the TV response. However, central pretreatment with nicotinic receptor antagonist mecamylamine blocked the respiratory and blood gas responses induced by nesfatin-1. The study's conclusion demonstrated that nesfatin-1 had active hyperventilation effects resulting in an increase in pO₂ and a decrease in pCO₂. The critical finding of the study was that activation of central cholinergic receptors was involved in nesfatin-1-evoked hyperventilation and blood gas responses.

Targeting Histamine and Histamine Receptors for the Precise Regulation of Feeding

Histamine has long been accepted as an anorexigenic agent. However, lines of evidence have suggested that the roles of histamine in feeding behaviors are much more complex than previously thought, being involved in satiety, satiation, feeding motivation, feeding circadian rhythm, and taste perception and memory. The functional diversity of histamine makes it a viable target for clinical management of obesity and other feeding-related disorders. Here, we update the current knowledge about the functions of histamine in feeding and summarize the underlying molecular and neural circuit mechanisms. Finally, we review the main clinical studies about the impacts of histamine-related compounds on weight control and discuss insights into future research on the roles of histamine in feeding. Despite the recent progress in histamine research, the histaminergic feeding circuits are poorly understood, and it is also worth verifying the functions of histamine receptors in a more spatiotemporally specific manner.

Nucleobindin-derived nesfatin-1 and nesfatin-1-like peptide stimulate pro-opiomelanocortin synthesis in murine AtT-20 corticotrophs through the cAMP/PKA/CREB signaling pathway

Nucleobindin (NUCB)-derived peptides, nesfatin-1 (NES-1) and nesfatin-1-like peptide (NLP) have several physiological roles in vertebrates. While NES-1 is implicated in stress, whether NUCB1/NLP and NUCB2/NES-1 have any effect on proopiomelanocortin (POMC) remains unknown. The main aim of this study was to determine if NES-1 and/or NLP affect POMC synthesis in mouse corticotrophs. Immunocytochemistry was employed to target NUCB colocalization with POMC in immortalized mouse tumoral corticotrophs (AtT-20 cells). The ability of NES-1 and NLP to modulate POMC mRNA and protein in AtT-20 cells was assessed by qPCR and Western blot, respectively. Moreover, cell-signaling molecules mediating the effect of NES-1 and NLP on POMC synthesis in mouse tumoral corticotrophs were studied using pharmacological blockers. Mouse tumoral corticotrophs showed immunoreactivity for both NUCB1/NLP and NUCB2/NES-1. Both NES-1 and NLP exerted a stimulatory effect on POMC transcript abundance and protein expression in a dose- and time-dependent manner. This effect was comparable to corticotropin-releasing factor (CRF, positive control) stimulation of POMC. Incubation of mouse tumoral corticotrophs with NES-1 or NLP upregulated the phosphorylation of protein kinase A (PKA) and cAMP-response element-binding protein (CREB). The stimulatory effect of these peptides on POMC transcript abundance and protein expression was blocked by the PKA inhibitor, H89, and an adenylate cyclase inhibitor, 2',3'-dideoxyadenosine (DDA). These pharmacological studies indicate that NES-1 and NLP act through the cAMP/PKA/CREB cellular pathway to stimulate POMC synthesis. Our results provide molecular evidence to support a stimulatory role for nucleobindin-derived peptides on POMC synthesis from corticotrophs. Collectively, this research indicates that corticotrophs produce NUCBs, and the encoded peptides NES-1 and NLP could elicit a direct action to stimulate the pituitary stress hormone. This stimulatory effect is mediated by an uncharacterized G protein-coupled receptor (GPCR) that utilizes the cAMP/PKA/CREB pathway.

A comparative account of nesfatin-1 in vertebrates

Nesfatin-1 was discovered as an anorexigenic peptide derived from proteolytic cleavage of the prepropeptide, nucleobindin 2 (NUCB2). It is widely expressed in central as well as peripheral tissues and is known to have pleiotropic effects such as regulation of feeding, reproduction, cardiovascular functions and maintenance of glucose homeostasis. In order to execute its multifaceted role, nesfatin-1 employs diverse signaling pathways though its receptor has not been identified till date. Further, nesfatin-1 is reported to be under the regulatory effect of feeding state, nutritional status as well as several metabolic and reproductive hormones. This peptide has also been associated with variety of human diseases, especially metabolic, reproductive, cardiovascular and mental disorders. The current review is aimed to present a consolidated picture and highlight lacunae for further investigation in order to develop a deeper comprehensive understanding on physiological significance of nesfatin-1 in vertebrates.

Nesfatin-1 in lipid metabolism and lipid-related diseases

Nesfatin-1, an anorexic neuropeptide discovered in 2006, is widely distributed in the central nervous system and peripheral tissues. It has been shown to be involved in the regulation of food intake and lipid metabolism, inhibiting fat accumulation, accelerating lipid decomposition, and in general, inhibiting the development of lipid-related diseases, such as obesity and metabolic syndrome. Potential mechanisms of Nesfatin-1 action in lipid metabolism and lipid-related diseases will be discussed as well as its role as a biomarker in cardiovascular disease. This review expected to provide a new strategy for the diagnosis and prevention of clinically related diseases.

Centrally Projecting Edinger-Westphal Nucleus in the Control of Sympathetic Outflow and Energy Homeostasis

The centrally projecting Edinger-Westphal nucleus (EWcp) is a midbrain neuronal group, adjacent but segregated from the preganglionic Edinger-Westphal nucleus that projects to the ciliary ganglion. The EWcp plays a crucial role in stress responses and in maintaining energy homeostasis under conditions that require an adjustment of energy expenditure, by virtue of modulating heart rate and blood pressure, thermogenesis, food intake, and fat and glucose metabolism. This modulation is ultimately mediated by changes in the sympathetic outflow to several effector organs, including the adrenal gland, heart, kidneys, brown and white adipose tissues and pancreas, in response to environmental conditions and the animal's energy state, providing for appropriate energy utilization. Classic neuroanatomical studies have shown that the EWcp receives inputs from forebrain regions involved in these functions and projects to presympathetic neuronal populations in the brainstem. Transneuronal tracing with pseudorabies virus has demonstrated that the EWcp is connected polysynaptically with central circuits that provide sympathetic innervation to all these effector organs that are critical for stress responses and energy homeostasis. We propose that EWcp integrates multimodal signals (stress, thermal, metabolic, endocrine, etc.) and modulates the sympathetic output simultaneously to multiple effector organs to maintain energy homeostasis under different conditions that require adjustments of energy demands.

Chemogenetic activation of endogenous arginine vasopressin exerts anorexigenic effects via central nesfatin-1/NucB2 pathway

We examined whether the chemogenetic activation of endogenous arginine vasopressin (AVP) affects central nesfatin-1/NucB2 neurons, using a transgenic rat line that was previously generated. Saline (1 mL/kg) or clozapine-N-oxide (CNO, 1 mg/mL/kg), an agonist for hM3Dq, was subcutaneously administered in adult male AVP-hM3Dq-mCherry transgenic rats (300-370 g). Food and water intake were significantly suppressed after subcutaneous (s.c.) injection of CNO, with aberrant circadian rhythmicity. The percentages of Fos expression in nesfatin-1/NucB2-immunoreactive neurons were significantly increased in the hypothalamus and brainstem at 120 min after s.c. injection of CNO. Suppressed food intake that was induced by chemogenetic activation of endogenous AVP was ablated after intracerebroventricularly administered nesfatin-1/NucB2-neutralizing antibody in comparison with vehicle, without any alteration of water intake nor circadian rhythmicity. These results suggest that chemogenetic activation of endogenous AVP affects, at least in part, central nesfatin-1/NucB2 neurons and may exert anorexigenic effects in the transgenic rats.

The intermediary role of the central cyclooxygenase / lipoxygenase enzymes in intracerebroventricular injected nesfatin-1-evoked cardiovascular effects in rats

That nesfatin-1 is a neuromodulatory peptide for the cardiovascular system is well documented. Several central receptors have been shown to mediate the cardiovascular effects of nesfatin-1. Immunohistochemistry and Western blot studies showed that nesfatin-1 activated the expression of the central cyclooxygenase (COX) -1, -2 and lipoxygenase (LOX). In addition, microdialysis study showed that nesfatin-1 increased the release of total prostaglandins and leukotrienes from the hypothalamus. The present study investigated whether the central COX and LOX enzymes have a direct mediating role in the MAP and HR responses of nesfatin-1. Intracerebroventricularly administered nesfatin-1 produced dose-dependent pressor and phasic HR responses in normotensive conscious rats Sprague Dawley. Central pretreatment with a COX1/2 inhibitor, ibuprofen, completely blocked the nesfatin-1-induced responses. However, central pretreatment with a nonselective LOX inhibitor, nordihydroguaiaretic acid, partially attenuated the cardiovascular responses induced by nesfatin-1. The results suggest that centrally administered nesfatin-1 activates the central enzymes COX and LOX, which may be involved in the cardiovascular responses as a novel central mechanism for nesfatin-1.

RF-amide related peptide-3 (RFRP-3): a novel neuroendocrine regulator of energy homeostasis, metabolism, and reproduction

A hypothalamic neuropeptide, RF-amide related peptide-3 (RFRP-3), the mammalian ortholog of the avian gonadotropin-inhibitory hormone (GnIH) has inhibitory signals for reproductive axis via G-protein coupled receptor 147 in mammals. Moreover, RFRP-3 has orexigenic action but the mechanism involved in energy homeostasis and glucose metabolism is not yet known. Though, the RFRP-3 modulates orexigenic action in co-operation with other neuropeptides, which regulates metabolic cues in the hypothalamus. Administration of GnIH/RFRP-3 suppresses plasma luteinizing hormone, at the same time stimulates feeding behavior in birds and mammals. Likewise, in the metabolically deficient conditions, its expression is up-regulated suggests that RFRP-3 contributes to the integration of energy balance and reproduction. However, in many other metabolic conditions like induced diabetes and high-fat diet obesity, etc. its role is still not clear while, RFRP-3 induces the glucose homeostasis by adipocytes is reported. The physiological role of RFRP-3 in metabolic homeostasis and the metabolic effects of RFRP-3 signaling in pharmacological studies need a detailed discussion. Further studies are required to find out whether RFRP-3 is associated with restricted neuroendocrine function observed in type II diabetes mellitus, aging, or sub-fertility. In this context, the current review is focused on the role of RFRP-3 in the above-mentioned mechanisms. Studies from search engines including PubMed, Google Scholar, and science.gov are included after following set inclusion/exclusion criteria. As a developing field few mechanisms are still inconclusive, however, based on the available information RFRP-3 seems to be a putative tool in future treatment strategies towards metabolic disease.

Plasma Nesfatin-1: Potential Predictor and Diagnostic Biomarker for Cognitive Dysfunction in T2DM Patient

PURPOSE

Nesfatin-1 plays a crucial role in glucose metabolism and cognitive function. This study aimed to investigate the correlation between plasma nesfatin-1 levels and clinical indicators and cognitive function in patients with type 2 diabetes mellitus (T2DM).

METHODS

Demographic and medical history data, physical examination, and biochemical test results of 132 T2DM patients were collected. The plasma concentrations of nesfatin-1, C-reactive protein (CRP), interleukin-6 (IL-6), soluble triggering receptors expressed on myeloid cells 1 (sTREM1), and sTREM2 in T2DM patients were measured. Cognitive function was evaluated using the Behavior Rating Inventory of Executive Function-Adult (BRIEF-A). The patients were divided into two groups: a low-nesfatin-1 group (n = 75) and a high-nesfatin-1 group (n = 57) based on a plasma nesfatin-1 concentration less than or above the 50th percentile value of all the samples.

RESULTS

The results showed that plasma HbA1c levels were positively correlated with CRP, IL-6, sTREM1, and sTREM2 levels in patients with T2DM (P < 0.05). Plasma nesfatin-1 concentrations were positively associated with diabetes-related biochemical indicators including glycated haemoglobin (HbA1c), insulin, and homeostatic model assessment of insulin resistance (HOMA-IR), and inflammation-related indicators including CRP, IL-6, sTREM1, and sTREM2 among patients with T2DM (P < 0.05). Moreover, T2DM patients with high nesfatin-1 levels showed higher HbA1c and fasting plasma glucose (FPG) levels (P < 0.05). Furthermore, T2DM patients with high nesfatin-1 levels also showed higher BRIEF-A scores (P = 0.01). Additionally, T2DM patients with high total scores of BRIEF-A (scores > 50th percentile) could be identified with a sensitivity of 59.1% and a specificity of 72.7% by nesfatin-1.

CONCLUSION

These findings indicate that plasma nesfatin-1 might be involved in the T2DM-associated comorbidities and the development of cognitive dysfunction, and the mechanism underlying this involvement is related to the imbalance in the expression of CRP, IL-6, sTREM1, and sTREM2 levels.

Nesfatin-1 Receptor: Distribution, Signaling and Increasing Evidence for a G Protein-Coupled Receptor - A Systematic Review

BACKGROUND

Nesfatin-1 is an 82-amino acid polypeptide, cleaved from the 396-amino acid precursor protein nucleobindin-2 (NUCB2) and discovered in 2006 in the rat hypothalamus. In contrast to the growing body of evidence for the pleiotropic effects of the peptide, the receptor mediating these effects and the exact signaling cascades remain still unknown.

METHODS

This systematic review was conducted using a search in the Embase, PubMed, and Web of Science databases. The keywords "nesfatin-1" combined with "receptor", "signaling", "distribution", "pathway", g- protein coupled receptor", and "binding" were used to identify all relevant articles reporting about potential nesfatin-1 signaling and the assumed mediation via a G_i protein-coupled receptor.

RESULTS

Finally, 1,147 articles were found, of which 1,077 were excluded in several steps of screening, 70 articles were included in this systematic review. Inclusion criteria were studies investigating nesfatin-1's putative receptor or signaling cascade, observational preclinical and clinical studies, experimental studies, registry-based studies, cohort studies, population-based studies, and studies in English language. After screening for eligibility, the studies were assigned to the following subtopics and discussed regarding intracellular signaling of nesfatin-1 including the potential receptor mediating these effects and downstream signaling of the peptide.

CONCLUSION

The present review sheds light on the various effects of nesfatin-1 by influencing several intracellular signaling pathways and downstream cascades, including the peptide's influence on various hormones and their receptors. These data point towards mediation via a G_i protein-coupled receptor. Nonetheless, the identification of the nesfatin-1 receptor will enable us to better investigate the exact mediating mechanisms underlying the different effects of the peptide along with the development of agonists and antagonists.

Nesfatin-1 and neuronostatin neurons are co-expressed with glucocorticoid receptors in the hypothalamus

Nesfatin-1 and neuronostatin in the central nervous system participate in regulating stress responses. Glucocorticoid hormones affect the brain through glucocorticoid receptors (GR). We investigated in the rat the possibility of co-localizing nesfatin-1 and neuronostatin neurons in hypothalamic areas with GR. using immunohistochemistry. We counted nesfatin-1 and neuronostatin stained neurons. We counted GR positive nesfatin-1 neurons in the arcuate nucleus (ARC) and paraventricular nucleus (PVN) and GR positive neuronostatin neurons in the periventricular nucleus (PeN). The percentage of nesfatin-1 neurons that expressed GR was 38.4% in female rats and 21.9% in male rats in the ARC, and 33.3% in female rats and 29.2% in male rats in the PVN. The percentage of neuronostatin neurons that expressed GR was 39.1% in female rats and 39.9% in male rats in the PeN. We found that a substantial portion of nesfatin-1 and neuronostatin neurons were stained for GR. We speculate that the pattern of GR might permit secretion of neuropeptides to be stimulated by peripheral glucocorticoid signals. Stress can suppress food intake, in part, through the GR in neurons that express nesfatin-1, which is a satiety molecule, and in neurons that express neuronostatin, which is an anorexigenic peptide.

Antioxidant, Anti-Inflammatory and Anti-Apoptotic Activities of Nesfatin-1: A Review

Nesfatin-1, a newly identified energy-regulating peptide, is widely expressed in the central and peripheral tissues, and has a variety of physiological activities. A large number of recent studies have shown that nesfatin-1 exhibits antioxidant, anti-inflammatory, and anti-apoptotic properties and is involved in the occurrence and progression of various diseases. This review summarizes current data focusing on the therapeutic effects of nesfatin-1 under different pathophysiological conditions and the mechanisms underlying its antioxidant, anti-inflammatory, and anti-apoptotic activities.

Immunohistochemical Evidence for Glutamatergic Regulation of Nesfatin-1 Neurons in the Rat Hypothalamus

Nesfatin-1, identified as an anorexigenic peptide, regulates the energy metabolism by suppressing food intake. The majority of nesfatin-1-synthesizing neurons are concentrated in various hypothalamic nuclei, especially in the supraoptic (SON), arcuate (ARC) and paraventricular nuclei (PVN). We tested the hypothesis that the glutamatergic system regulates nesfatin-1 neurons through glutamate receptors. Therefore, the first aim of the proposed studies was to examine effects of different glutamate agonists in the activation of nesfatin-1 neurons using c-Fos double immunohistochemical labeling. Experimental groups were formed containing male and female rats which received intraperitoneal injections of glutamate agonists kainic acid, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartate (NMDA) while the control rats received vehicle. The significant increase in the number of c-Fos-expressing nesfatin-1 neurons after agonist injections were observed both in female and male subjects and some of these effects were found to be sexually dimorphic. In addition, treatment with specific glutamate antagonists 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) or dizocilpine (MK-801) before each of the three agonist injections caused a statistically significant reduction in the number of activated nesfatin-1 neurons in the hypothalamic nuclei including supraoptic, paraventricular and arcuate nuclei. The second aim of the study was to determine the expression of glutamate receptor subunit proteins in the nesfatin-1 neurons by using a double immunofluorescence technique. The results showed that the glutamate receptor subunits, which may form homomeric or heteromeric functional receptor channels, were expressed in the nesfatin-1 neurons. In conclusion, the results of this study suggest that nesfatin-1 neurons respond to glutamatergic signals in the form of neuronal activation and that the glutamate receptors that are synthesized by nesfatin-1 neurons may participate in the glutamatergic regulation of these neurons.

Nesfatin-1 decreases the motivational and rewarding value of food

Homeostatic and hedonic pathways distinctly interact to control food intake. Dysregulations of circuitries controlling hedonic feeding may disrupt homeostatic mechanisms and lead to eating disorders. The anorexigenic peptides nucleobindin-2 (NUCB2)/nesfatin-1 may be involved in the interaction of these pathways. The endogenous levels of this peptide are regulated by the feeding state, with reduced levels following fasting and normalized by refeeding. The fasting state is associated with biochemical and behavioral adaptations ultimately leading to enhanced sensitization of reward circuitries towards food reward. Although NUCB2/nesfatin-1 is expressed in reward-related brain areas, its role in regulating motivation and preference for nutrients has not yet been investigated. We here report that both dopamine and GABA neurons express NUCB2/nesfatin-1 in the VTA. Ex vivo electrophysiological recordings show that nesfatin-1 hyperpolarizes dopamine, but not GABA, neurons of the VTA by inducing an outward potassium current. In vivo, central administration of nesfatin-1 reduces motivation for food reward in a high-effort condition, sucrose intake and preference. We next adopted a 2-bottle choice procedure, whereby the reward value of sucrose was compared with that of a reference stimulus (sucralose + optogenetic stimulation of VTA dopamine neurons) and found that nesfatin-1 fully abolishes the fasting-induced increase in the reward value of sucrose. These findings indicate that nesfatin-1 reduces energy intake by negatively modulating dopaminergic neuron activity and, in turn, hedonic aspects of food intake. Since nesfatin-1´s actions are preserved in conditions of leptin resistance, the present findings render the NUCB2/nesfatin-1 system an appealing target for the development of novel therapeutical treatments towards obesity.

Nucleobindin 2/nesfatin-1 expression and colocalisation with neuropeptide Y and cocaine- and amphetamine-regulated transcript in the human brainstem

Feeding is a complex behaviour entailing elaborate interactions between forebrain, hypothalamic and brainstem neuronal circuits via multiple orexigenic and anorexigenic neuropeptides. Nucleobindin-2 (NUCB2)/nesfatin-1 is a negative regulator of food intake and body weight with a widespread distribution in rodent brainstem nuclei. However, its localisation pattern in the human brainstem is unknown. The present study aimed to explore NUCB2/nesfatin-1 immunoexpression in human brainstem nuclei and its possible correlation with body weight. Sections of human brainstem from 20 autopsy cases (13 males, seven females; eight normal weight, six overweight, six obese) were examined using immunohistochemistry and double immunofluorescence labelling. Strong immunoreactivity for NUCB2/nesfatin-1 was displayed in various brainstem areas, including the locus coeruleus, medial and lateral parabrachial nuclei, pontine nuclei, raphe nuclei, nucleus of the solitary tract, dorsal motor nucleus of vagus (10N), area postrema, hypoglossal nucleus, reticular formation, inferior olive, cuneate nucleus, and spinal trigeminal nucleus. NUCB2/nesfatin-1 was shown to extensively colocalise with neuropeptide Y and cocaine- and amphetamine-regulated transcript in the locus coeruleus, dorsal raphe nucleus and solitary tract. Interestingly, in the examined cases, NUCB2/nesfatin-1 protein expression was lower in obese than normal weight subjects in the solitary tract (P = 0.020). The findings of the present study provide neuroanatomical support for a role for NUCB2/nesfatin-1 in feeding behaviour and energy balance. The widespread distribution of NUCB2/nesfatin-1 in the human brainstem nuclei may be indicative of its pleiotropic effects on autonomic, neuroendocrine and behavioural processes. In the solitary tract, a key integrator of energy status, altered neurochemistry may contribute to obesity. Further research is necessary to decipher human brainstem energy homeostasis circuitry, which, despite its importance, remains inadequately characterised.

Neural remodelling in spiny lobster larvae is characterized by broad neuropeptide suppression

Neuropeptides are ancient endocrine components which have evolved to regulate many aspects of biology across the animal kingdom including behaviour, development and metabolism. To supplement current knowledge, we have utilized a transcriptome series describing larval development in the ornate spiny lobster, Panulirus ornatus. The biology of this animal has been leveraged to provide insights into the roles of molting, metamorphosis and metabolism across the neuropeptide family. We report an extensive list of neuropeptides across three distinct life phases of the animal. We show distinct groups of neuropeptides with differential expression between larval phases, indicating phase-specific roles for these peptides. For selected neuropeptides, we describe and discuss expression profiles throughout larval development and report predicted peptide cleavage sites and mature peptide sequences. We also report the neuropeptide nesfatin for the first time in a crustacean, and report secondary peptide products with a level of evolutionary conservation similar to the conventional mature peptide nesfatin-1, indicating a conserved role in these secondary products which are widely regarded as biologically inactive. In addition, we report a trend of downregulation in the neuropeptides as the animal undergoes extensive neural remodelling in fulfillment of metamorphosis. We suggest that this downregulation in neuropeptides relates to the brief, yet dramatic changes in morphology experienced by the central nervous system in the process of metamorphosis.

Intracerebroventricularly injected nesfatin-1 activates central cyclooxygenase and lipoxygenase pathways

Nesfatin-1 is a multifunctional neuropeptide having crucial autonomic roles. It is well known that nesfatin-1 collaborates with other central neuromodulatory systems, such as central corticotropin-releasing hormone, melanocortin, oxytocin, and cholinergic systems to show its autonomic effects. Central arachidonic acid cascade plays an important role to provide the homeostasis by exhibiting similar autonomic effects to nesfatin-1. Based on these similarities, the current study was designed to show the effects of intracerebroventricularly (ICV) injected nesfatin-1 on the hypothalamic arachidonic acid (AA) cascade. Immunochemistry and western blot approaches demonstrated that ICV administration of nesfatin-1 provokes an increase in the hypothalamic cyclooxygenase (COX) -1, -2 and lipoxygenase (LOX) protein expression. Moreover, the microdialysis study demonstrated that centrally injected nesfatin-1 increased the posterior hypothalamic extracellular AA products. In conclusion, these findings report that while nesfatin-1 is generating its autonomic effects, it also might be using central prostaglandins and leukotrienes by activating central COX and LOX pathways.

Nesfatin-1 in cardiovascular orchestration: From bench to bedside

Since the discovery of Nesfatin-1 in 2006, intensive research was finalized to further and deeper investigate the precise physiological functions of the peptide at both central and peripheral levels, rapidly enriching the knowledge regarding this intriguing molecule. Nesfatin-1 is a hypothalamic peptide generated via the post-translational processing of its precursor Nucleobindin 2, a protein supposed to play a role in many biological processes thanks to its ability to bind calcium and to interact with different intracellular proteins. Nesfatin-1 is mainly known for its anorexic properties, but it also controls water intake and glucose homeostasis. Recent experimental evidences describe the peptide as a possible direct/indirect orchestrator of central and peripheral cardiovascular control. A specific Nesfatin-1 receptor still remains to be identified although numerous studies suggest that the peptide activates extra- and intracellular regulatory pathways by involving several putative binding sites. The present paper was designed to systematically review the latest findings about Nesfatin-1, focusing on its cardiovascular regulatory properties under normal and physiopathological conditions. The hope is to provide the conceptual basis to consider Nesfatin-1 not only as a pleiotropic neuroendocrine molecule, but also as a homeostatic modulator of the cardiovascular function and with a crucial role in cardiovascular diseases.

Can Nesfatin-1 Predict Hypertension in Obese Children?

Objective

The prevalence of childhood obesity is increasing and leads to co-morbidities such as hypertension. However, it is still not clear why some obese individuals are hypertensive and others not. Nesfatin-1 is a recently discovered anorexigenic peptide which also has effects on blood pressure (BP). Our aim was to evaluate the relationship between obesity-related hypertension and Nesfatin-1.

Methods

This cross-sectional study comprised 87 obese children. The patients were divided into two groups; hypertensive (n=30) and normotensive (n=57) obese. The American Academy of Pediatrics guidelines were used to diagnose hypertension. Blood samples were collected after 12 hours of fasting to investigate Nesfatin-1 concentrations. We also evaluated serum trace elements in addition to the routine blood tests.

Results

Body mass index (BMI), weight and serum Nesfatin-1 concentrations were higher in the hypertensive group (p=0.002, p=0.001, and p=0.007, respectively). There was no difference between serum zinc levels, but Copper (Cu) levels were significantly lower in the hypertensive group (p=0.248, p=0.007, respectively). There were positive correlations between BP and BMI and weight Z-scores and a negative correlation with Cu. The optimal cut-off value of Nesfatin-1 to predict hypertension was found to be >1.8 ng/mL, with a specificity of 71.9% and a sensitivity of 96.7% [area under the curve=0.703, 95% confidence interval (CI): 0.577-0.809; p=0.002]. In multiple logistic regression analysis Nesfatin-1 [Odds ratio (OR)=1.103, 95% CI: 1.039-1.171; p=0.001], Cu (OR=0.947, 95% CI: 0.915-0.979; p=0.001) and BMI for age Z-score (OR=56.277, 95% CI: 5.791-546.907; p=0.001) still remained significant predictors of hypertension.

Conclusion

Nesfatin-1 levels are higher and are an independent predictor of hypertension in obese subjects.

Centrally and peripherally injected nesfatin-1-evoked respiratory responses

Nesfatin-1, which is an anorexiogenic peptide, plays a crucial role as a neurotransmitter and/or neuromodulator in the central nervous system for cardiovascular control and energy balance etc. It is expressed abundantly in multiple brain nuclei including central respiratory control areas such as nucleus tractus solitarius, nucleus ambiguous, dorsal vagal complex, dorsal motor nucleus of the vagus nerve, and hypothalamus. To date, no previous studies have been found to report nesfatin-1-evoked respiratory effects. Therefore, the present study was designed to investigate the possible impacts of centrally and/or peripherally injected nesfatin-1 on respiratory parameters in either 12h-fasted or fed-ad libitum rats. Intracerebroventricular (ICV) administration of nesfatin-1 provoked significant hyperventilation by increasing tidal volume (TV), respiratory rate (RR) and respiratory minute ventilation (RMV) in both the 12h-fasted and the fed-ad libitum Spraque Dawley rats in dose- and time- dependent manner. Moreover, the hyperventilatory effects of centrally injected nesfatin-1 were more potent in the fed-ad libitum rats. Intravenous injection of nesfatin-1 induced a significant rise in RR and RMV, but not in TV, in the fed-ad libitum rats. In conclusion, these findings plainly report that both centrally and/or peripherally injected nesfatin-1 induces significant hyperventilatory effects in the 12h-fasted and the fed-ad libitum rats. These hyperventilatory effects of nesfatin-1 might show a discrepancy according to the food intake of the rats and the delivery method of the peptide.

Role of nesfatin-1 in anxiety, depression and the response to stress

Nesfatin-1 has been discovered a decade ago and since then drawn a lot of attention. The initially proposed anorexigenic effect was followed by the description of several other involvements such as a role in gastrointestinal motility, glucose homeostasis, cardiovascular functions and thermoregulation giving rise to a pleiotropic action of this peptide. The recent years witnessed mounting evidence on the involvement of nesfatin-1 in emotional processes as well. The present review will describe the peptide's relations to anxiety, depressiveness and stress in animal models and humans and also discuss existing gaps in knowledge in order to stimulate further research.

Nucleobindin-2/Nesfatin-1 in the Human Hypothalamus Is Reduced in Obese Subjects and Colocalizes with Oxytocin, Vasopressin, Melanin-Concentrating Hormone, and Cocaine- and Amphetamine-Regulated Transcript

BACKGROUND/AIMS

Nesfatin-1, processed from nucleobindin-2 (NUCB2), is a potent anorexigenic peptide being expressed in rodent hypothalamic nuclei and involved in the regulation of feeding behavior and body weight in animals. The present study aimed to investigate NUCB2/nesfatin-1 protein expression in the human hypothalamus as well as its correlation with body weight.

METHODS

Sections of hypothalamus and adjacent cholinergic basal forebrain nuclei, including the nucleus basalis of Meynert (NBM) and the diagonal band of Broca (DBB), from 25 autopsy cases (17 males, 8 females; 8 lean, 9 overweight, 8 obese) were examined using immunohistochemistry and double immunofluorescence labeling.

RESULTS

Prominent NUCB2/nesfatin-1 immunoexpression was detected in supraoptic, paraventricular, and infundibular nuclei, lateral hypothalamic area (LHA)/perifornical region, and NBM/DBB. NUCB2/nesfatin-1 was found to extensively colocalize with (a) oxytocin and vasopressin in paraventricular and supraoptic nuclei, (b) melanin-concentrating hormone in the LHA, and (c) cocaine- and amphetamine-regulated transcript in infundibular and paraventricular nuclei and LHA. Interestingly, in the LHA, NUCB2/nesfatin-1 protein expression was significantly decreased in obese, compared with lean (p < 0.01) and overweight (p < 0.05) subjects.

CONCLUSIONS

The findings of the present study are suggestive of a potential role for NUCB2/nesfatin-1 as an integral regulator of food intake and energy homeostasis in the human hypothalamus. In the LHA, an appetite- and reward-related brain area, reduced NUCB2/nesfatin-1 immunoexpression may contribute to dysregulation of homeostatic and/or hedonic feeding behavior and obesity. NUCB2/nesfatin-1 localization in NBM/DBB might imply its participation in the neuronal circuitry controlling cognitive influences on food intake and give impetus towards unraveling additional biological actions of NUCB2/nesfatin-1 in human neuronal networks.

SERUM NESFATIN-1 LEVEL IN HEALTHY SUBJECTS WITH WEIGHT-RELATED ABNORMALITIES AND NEWLY DIAGNOSED PATIENTS WITH TYPE 2 DIABETES MELLITUS; A CASE-CONTROL STUDY

Context

Nesfatin-1 is a novel peptide with both central and peripheral anorexigenic regulatory properties. Besides its effects on food intake, few studies have suggested a possible role for this peptide in the pathogenesis of diabetes mellitus type 2.

Objective

To compare serum levels of nesfatin-1 between healthy, normal-weight persons and three groups including healthy underweight, healthy obese and diabetic subjects.

Design

Prospective, case-control study, performed between January 2015 and January 2016.

Subjects and Methods

Fasting levels in serum nesfatin-1 were measured in 30 healthy, normal-weight individuals (controls), 30 healthy underweight persons, 30 healthy obese persons, and 30 patients with newly diagnosed diabetes type 2 using standard enzyme-linked immunosorbent assay (ELISA) kits.

Results

The mean serum nesfatin-1 level was significantly higher in controls (2.61 ng/mL) compared to that in obese (1.13 ng/mL) and diabetic (0.99 ng/mL) patients; and significantly lower than that in the underweight group (3.50 ng/mL). The obese and diabetic groups were comparable in this regard. No significant association was found between serum nesfatin-1 level and age, sex, or body mass index.

Conclusions

Serum nesfatin-1 is possibly associated with weight-related abnormalities in otherwise healthy subjects and diabetes type 2. Obesity and diabetes type 2 may share a common pathologic point in this regard.

Tissue-Specific Localization NUCB2/nesfatin-1 in the Liver and Heart of Mouse Fetus

NUCB2/nesfatin-1 is first known to be expressed in the hypothalamus while controlling appetite and energy metabolism. However, recent studies have shown that NUCB2/nesfatin-1 was expressed in the various organs as well as the hypothalamus. Our previous reports also demonstrated that NUCB2/nesfatin-1 was expressed in the ovary, testis, pituitary gland, lung, kidney, and stomach of fetal and adult mice. However, the role of NUCB2/nesfatin-1 in mouse fetus remains unknown. Thus, the aim of this study was to investigate whether NUCB2/nestatin-1 is expressed in mouse fetus at the developmental stage in which organogenesis begins. To do this, we performed in situ hybridization (ISH) and immunohistochemistry (IHC) staining to examine the distribution of NUCB2 mRNA and nesfatin-1 protein in the mouse fetal organs during early developmental stages, especially at embryonic day (E) 10.5. As a result of ISH, NUCB2 mRNA positive signals were more frequent in the liver, but there were relatively few positive signals in heart. On the other hand, no positive signals were detected in other organs. These ISH results were validated by IHC staining and qRT-PCR analysis. Expression of nesfatin-1 protein detected by IHC staining was similar to that of NUCB2 mRNA detected by ISH in the liver and heart. In addition, the levels of NUCB2 mRNA expression analyzed by qRT-PCR were significantly increased in the liver and heart compared to other organs of the mouse fetus at E13.5, whereas its level was extensively decreased in the liver, but increased in the lung, stomach, and kidney of the mouse fetus at E17.5. These results suggest that NUCB2/nesfatin-1 may play an important role in liver and heart development and physiological functions in the developmental process of mouse fetus. Further studies are needed on the function of NUCB2/nesfatin-1, which is highly expressed in the various organs, including liver and heart during mouse development.

Current Understanding of the Role of Nesfatin-1

Nesfatin-1 was discovered in 2006 and implicated in the regulation of food intake. Subsequently, its widespread central and peripheral distribution gave rise to additional effects. Indeed, a multitude of actions were described, including modulation of gastrointestinal functions, glucose and lipid metabolism, thermogenesis, mediation of anxiety and depression, as well as cardiovascular and reproductive functions. Recent years have witnessed a great increase in our knowledge of these effects and their underlying mechanisms, which will be discussed in the present review. Lastly, gaps in knowledge will be highlighted to foster further studies.