Restraint stress affects circulating NUCB2/nesfatin-1 and phoenixin levels in male rats

The role of nesfatin-1 in kidney diseases

Nesfatin-1 is a recently discovered protein with a pleiotropic function on various organs, including kidneys. This molecule presents antiapoptotic, antihyperglycemic, antioxidative, and anorectic features. Available data regarding the role of nesfatin-1 in kidney function and diseases focuses on chronic kidney disease, acute kidney injury, blood pressure, and renal cell carcinoma. Various studies have shown that the levels of nesfatin-1 were increased in patients with diabetic kidney disease (DKD); therefore, it was suggested that nesfatin-1 might act as an early DKD marker. Furthermore, the potential protective function of nesfatin-1 against inflammation, oxidative stress, fibrosis, and apoptosis in kidney tissues was described in several studies. Alternatively, as reported in the literature, a positive correlation between blood pressure elevation and nesfatin-1 levels was noted. Moreover, nesfatin-1 might exert influence on renal cell carcinoma progression and invasion of cancerous cells. Nesfatin-1 shows considerable potential for acting as a prognostic marker or a defensive factor for kidney diseases; however, further investigation, especially in the pediatric population, is still required.

Antidepressant and anxiolytic effects of Wuling Capsule in CSDS mice: Alleviating HPA axis hyperactivity via the Nesfatin-1/NF-κB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Wuling capsule, composed of the traditional Chinese medicine Wuling mycelia powder, is made by fermenting and processing Xylaria nigripes (Kl.) Sacc. Clinically, it is commonly used to alleviate depression and anxiety. However, the mechanisms through which Wuling capsule exerts its therapeutic benefits have not been clearly defined.

AIM OF THE STUDY

This study aims to elucidate the mechanisms by which Wuling capsule alleviates depression and anxiety like behaviors induced by chronic social defeat stress (CSDS) in mice.

MATERIALS AND METHODS

High-performance liquid chromatography-tandem mass spectrometry system was used to identify the components of the Wuling capsule. Mice were subjected to CSDS to induce depression and anxiety-like behaviors. The expression of hypothalamic corticotropin-releasing hormone (CRH) and Nesfatin-1, as well as serum levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were quantified. Behavioral assessments included the open field test, elevated plus maze, sucrose preference test, and forced swim test to evaluate depression and anxiety levels. Specific manipulation of Nesfatin-1 in the paraventricular nucleus of the hypothalamus (PVN) or cells was achieved through stereotaxic virus injection or plasmid transfection. Intracerebral cannula implantation was used for PVN-specific drug administration.

RESULTS

A total of 123 different components were identified in Wuling capsule. CSDS induced depression and anxiety-like behaviors in mice, along with hyperactivation of the HPA axis, increased hypothalamic Nesfatin-1 levels, and elevated nuclear factor kappa-B (NF-κB) phosphorylation. Overexpression of Nesfatin-1 in the hypothalamus mimicked the effects of CSDS. Conversely, knockdown of hypothalamic Nesfatin-1 or PVN-specific administration of Nesfatin-1 antibody or NF-κB antagonist mitigated CSDS-induced depression and anxiety-like behaviors and hypothalamic-pituitary-adrenal (HPA) axis hyperactivity. In neuroblastoma-2a (N2a) cells, overexpression of Nesfatin-1 led to increased NF-κB phosphorylation and CRH levels, whereas knockdown of Nesfatin-1 produced the opposite effects. Treatment with Wuling capsule alleviated CSDS-induced depression and anxiety-like behaviors, HPA axis hyperactivity, and activation of the hypothalamic Nesfatin-1/NF-κB pathway.

CONCLUSIONS

The hypothalamic Nesfatin-1/NF-κB pathway plays a significant role in depression by modulating the HPA axis and is involved in the antidepressant and anxiolytic effects of Wuling capsule.

Stress induces nucleobindin-1 mRNA and nesfatin-1-like peptide stimulates cortisol secretion in goldfish

Stress is a state of disrupted homeostasis triggered by physical or psychological stimuli that elicit adaptive responses at the molecular and cellular levels. In fish, the hypothalamus-pituitary-interrenal (HPI) axis mediates stress responses. Nesfatin-1 and a nesfatin-1-like peptide (NLP), derived from nucleobindin-1 (NUCB1), have been implicated in stress hormone regulation in mammals. This study investigated the cell-specific expression of NUCB1/NLP in HPI tissues and its effects on stress response in goldfish (Carassius auratus). NUCB1 mRNA is abundant in the hypothalamus, pituitary, and several other peripheral tissues of goldfish. NUCB1/NLP-like immunoreactivity was found in the brain and pituitary, co-localized with corticotropin-releasing factor receptor 1 (CRF-R1) in the hypothalamus, and with adrenocorticotrophic hormone (ACTH) in the pituitary. In vivo netting and restraint stress increased nucb1 and crf-r1 mRNAs in the brain and acth mRNA in the pituitary, as determined by RT-qPCR. Intraperitoneal injection of NLP increased cortisol in circulation, crf-r1 mRNA in the brain and acth mRNA in the pituitary. These findings suggest that NUCB1/NLP is a new player in mediating the endocrine stress response of goldfish through the HPI axis.

Neuropeptides in the hypothalamus

The hypothalamus is one of the most complex region in the central nervous system regarding neuroanatomy, neurochemical content, neuropeptide/classical neurotransmitter interactions, physiological actions, and pathophysiology. Hypothalamic neuropeptides have been involved in a large plethora of mechanisms related with obesity, anxiety, feeding, energy metabolism, defensive behavior, mood, and reproduction. The therapeutic potential of these findings is enormous but the physiological complexity occurring in the hypothalamus is huge due in part to the interactions between numerous neuropeptides as well as between neuropeptides and other neuroactive substances. Here, we review the development and neuroanatomy of the hypothalamus as well as the involvement of 31 neuropeptides in hypothalamic functions and pathologies. Alterations in the secretion, release, and/or concentrations of neuropeptides and/or their hypothalamic receptors can trigger different pathologies. Several therapeutic strategies that could be carried out by adjusting neuropeptide levels in the hypothalamus are suggested. The combination of imaging techniques with a detailed neurochemical knowledge of the hypothalamus would be an excellent diagnostic tool, allowing personalized treatment. Several approaches for future research that may contribute to improve or resolve these pathologies are also mentioned.

Examining the Potential Applicability of Orexigenic and Anorexigenic Peptides in Veterinary Medicine for the Management of Obesity in Companion Animals

This review article comprehensively explores the role of orexigenic and anorexigenic peptides in the management of obesity in companion animals, with a focus on clinical applications. Obesity in domestic animals, particularly dogs and cats, is prevalent, with significant implications for their health and well-being. Factors contributing to obesity include overfeeding, poor-quality diet, lack of physical activity, and genetic predispositions. Despite the seriousness of this condition, it is often underestimated, with societal perceptions sometimes reinforcing unhealthy behaviors. Understanding the regulation of food intake and identifying factors affecting the function of food intake-related proteins are crucial in combating obesity. Dysregulations in these proteins, whether due to genetic mutations, enzymatic dysfunctions, or receptor abnormalities, can have profound health consequences. Molecular biology techniques play a pivotal role in elucidating these mechanisms, offering insights into potential therapeutic interventions. The review categorizes food intake-related proteins into anorexigenic peptides (inhibitors of food intake) and orexigenic peptides (enhancers of food intake). It thoroughly examines current research on regulating energy balance in companion animals, emphasizing the clinical application of various peptides, including ghrelin, phoenixin (PNX), asprosin, glucagon-like peptide 1 (GLP-1), leptin, and nesfatin-1, in veterinary obesity management. This comprehensive review aims to provide valuable insights into the complex interplay between peptides, energy balance regulation, and obesity in companion animals. It underscores the importance of targeted interventions and highlights the potential of peptide-based therapies in improving the health outcomes of obese pets.

NUCB2/nesfatin-1 in the acute stress response of obese women with high and low anxiety

NUCB2/nesfatin-1 is an anorexigenic peptide hormone first known for its effects on energy homeostasis. More recently, a growing evidence suggests a role of NUCB2/nesfatin-1 in emotion regulation, particularly in the modulation of anxiety, depression and emotional stress response. Since stress-related mood disorders are often comorbid with obesity, we investigated the effect of acute psychosocial stress on circulating NUCB2/nesfatin-1 in obese women and normal-weight controls and its association with symptoms of anxiety. Forty women, 20 obese and 20 normal-weight controls, (aged between 27 and 46 years) were exposed to the Trier Social Stress Test (TSST). We assessed changes of plasma NUCB2/nesfatin-1, salivary cortisol, heart rate and subjective emotional state. Symptoms of anxiety (GAD-7), depressiveness (PHQ-9), perceived stress (PSQ-20), disordered eating (EDE-Q, EDI-2) and health-related quality of life (SF-8) were measured psychometrically. Obese women were further subdivided in a high and low anxiety group. Women with obesity displayed higher psychopathology compared to normal-weight controls. The TSST induced a biological and psychological stress response in both groups (p < 0.001). In normal-weight controls NUCB2/nesfatin-1 increased in response to stress (p = 0.011) and decreased during recovery (p < 0.050), while in obese women only the decrease during recovery was significant (p = 0.002). Obese women with high anxiety displayed higher NUCB2/nesfatin-1 levels than those in the low anxiety group (TSST: +34 %, p = 0.008; control condition: +52 %, p = 0.013). Our data substantiate the involvement of NUCB2/nesfatin-1 in the modulation of stress and anxiety. It remains unclear whether the attenuated stress response in obese subjects is due to metabolic changes or mental comorbidity.

Locked Out: Phoenixin-14 Does Not Cross a Stem-Cell-Derived Blood-Brain Barrier Model

Phoenixin-14 is a recently discovered peptide regulating appetite. Interestingly, it is expressed in the gastrointestinal tract; however, its supposed receptor, GPR173, is predominantly found in hypothalamic areas. To date, it is unknown how peripherally secreted phoenixin-14 is able to reach its centrally located receptor. To investigate whether phoenixin is able to pass the blood-brain barrier, we used an in vitro mono-culture blood-brain barrier (BBB) model consisting of brain capillary-like endothelial cells derived from human induced-pluripotent stem cells (hiPSC-BCECs). The passage of 1 nMol and 10 nMol of phoenixin-14 via the mono-culture was measured after 30, 60, 90, 120, 150, 180, 210, and 240 min using a commercial ELISA kit. The permeability coefficients (PC) of 1 nMol and 10 nMol phoenixin-14 were 0.021 ± 0.003 and 0.044 ± 0.013 µm/min, respectively. In comparison with the PC of solutes known to cross the BBB in vivo, those of phoenixin-14 in both concentrations are very low. Here, we show that phoenixin-14 alone is not able to cross the BBB, suggesting that the effects of peripherally secreted phoenixin-14 depend on a co-transport mechanism at the BBB in vivo. The mechanisms responsible for phoenixin-14's orexigenic property along the gut-brain axis warrant further research.

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.

Current state of phoenixin-the implications of the pleiotropic peptide in stress and its potential as a therapeutic target

Phoenixin is a pleiotropic peptide, whose known functions have broadened significantly over the last decade. Initially first described as a reproductive peptide in 2013, phoenixin is now recognized as being implicated in hypertension, neuroinflammation, pruritus, food intake, anxiety as well as stress. Due to its wide field of involvement, an interaction with physiological as well as psychological control loops has been speculated. It has shown to be both able to actively reduce anxiety as well as being influenced by external stressors. Initial rodent models have shown that central administration of phoenixin alters the behavior of the subjects when confronted with stress-inducing situations, proposing an interaction with the perception and processing of stress and anxiety. Although the research on phoenixin is still in its infancy, there are several promising insights into its functionality, which might prove to be of value in the pharmacological treatment of several psychiatric and psychosomatic illnesses such as anorexia nervosa, post-traumatic stress disorder as well as the increasingly prevalent stress-related illnesses of burnout and depression. In this review, we aim to provide an overview of the current state of knowledge of phoenixin, its interactions with physiological processes as well as focus on the recent developments in stress response and the possible novel treatment options this might entail.

Mild acute stress prevents the memory impairment induced by long-term isoflurane anesthesia

Objectives

Long-term isoflurane anesthesia exposure could result in postoperative cognitive dysfunction (POCD). Preoperative stress is also reported to be a risk factor of POCD. However, it is unknown whether acute stress could impair memory after long-term isoflurane anesthesia.

Methods

In this study, we categorized the mice with acute stress into mild (30 min restraint stress), moderate (60 min restraint stress), and severe (120 min restraint stress) stress groups and then we used Open-Field Test (OFT) to detect whether different scales of acute restraint stress successfully induced acute stress in mice. The memory performance of mice was measured using contextual and cued memory test, and the brain-derived neurotrophic factor protein levels of hippocampus was detected by Western blot.

Results

We verified that mild stress has pro-cognitive effect, but severe stress has amnestic effect. Moreover, we found that mild and moderate other than severe acute stress could partially attenuate the memory impairment induced by long-term isoflurane anesthesia.

Conclusion

Mild and moderate acute stress could partially attenuate the memory impairment induced by long-term isoflurane anesthesia.

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.

Regulation and physiological functions of phoenixin

Phoenixin is a newly discovered neuropeptide generated from small integral membrane protein 20. Phoenixin is a ligand for the G protein-coupled receptor 173 (GPR173) and has been detected in central and peripheral tissues of human, rats, mice, bovine, and zebrafish. It was initially involved in regulating reproductive function by stimulating the luteinizing hormone release from pituitary cells by increasing the level of gonadotropin-releasing hormone. Recently, many functions of phoenixin have been generalized, including regulation of food intake, memory, Alzheimer’s disease, anxiety, inflammation, neuronal and microglial activity, energy metabolism and body fluid balance, cardiovascular function, and endocrine activity. In addition, the interaction between phoenixin and nesfatin-1 have been revealed. The present article summarized the latest research progress on physiological function of phoenixin, suggesting that it is a potential target for novel drug development and clinical application.

Pre-metazoan origin of neuropeptide signalling

Neuropeptides are a diverse class of signaling molecules in metazoans. They occur in all animals with a nervous system and also in neuron-less placozoans. However, their origin has remained unclear because no neuropeptide shows deep homology across lineages, and none have been found in sponges. Here, we identify two neuropeptide precursors, phoenixin (PNX) and nesfatin, with broad evolutionary conservation. By database searches, sequence alignments, and gene-structure comparisons, we show that both precursors are present in bilaterians, cnidarians, ctenophores, and sponges. We also found PNX and a secreted nesfatin precursor homolog in the choanoflagellate Salpingoeca rosetta. PNX, in particular, is highly conserved, including its cleavage sites, suggesting that prohormone processing occurs also in choanoflagellates. In addition, based on phyletic patterns and negative pharmacological assays, we question the originally proposed GPR-173 (SREB3) as a PNX receptor. Our findings revealed that secreted neuropeptide homologs derived from longer precursors have premetazoan origins and thus evolved before neurons.

Mediatory role of the central NPY, melanocortine and corticotrophin systems on phoenixin-14 induced hyperphagia in neonatal chicken

Animal research indicates the neuropeptide Y (NPY), corticotrophin and melanocortin systems have a mediatory role in reward, however, how these substances interact with phenytoin-14 (PNX-14) induced food intake in birds remains to be identified. Accordingly, in this research eight tests were carried out to investigate the potential interactions of the NPY, melanocortin, as well as corticotrophin systems with PNX-14 on food consumption in neonatal chickens. In the first experiment, chickens were intracerebroventricular (ICV) injected with phosphate-buffered saline (PBS) and PNX-14 (0.8, 0.16, and 3.2 nmol). In second experiment, PBS, the antagonist of CRF₁/CRF₂ receptors (astressin-B, 30 μg) and PNX-14 + astressin-B were injected. In the rest of the experiments chicken received astressin2-B (CRF₂ receptor antagonist; 30 µg), SHU9119 (MCR₃/MCR₄ receptor antagonist, 0.5nomol), MCL0020 (MCR₄ receptor agonist, 0.5 nmol), B5063 (NPY₁ receptor antagonist, 1.25 μg), SF22 (NPY₂ receptor antagonist, 1.25 μg) and SML0891 (NPY₅ receptor antagonist, 1.25 μg) rather than astressin-B. Then, cumulative intake of food was recorded for 2 h. Based on the findings, PNX-14 (0.16 and 3.2 nmol) led to increment in food consumption compared with the control (P < 0.05). Co-administration of the PNX-14 and astressin-B promoted PNX-14-induced hyperphagia (P < 0.05). Co-injection of the PNX-14 + astressin2-B potentiated hyperphagia PNX-14 (P < 0.05). Co-injection of PNX-14 + B5063 inhibited the effects of the PNX-14 (P < 0.05). The co-administration of the PNX-14 and SML0891 potentiated hypophagic effects of the PNX-14 (P < 0.05). The results showed that PNX-14-induced hyperphagia mediates via NPY₁, NPY_5, and CRF₁/CRF₂ receptors in neonatal chickens.

The Regulation of Phoenixin: A Fascinating Multidimensional Peptide

The phoenixin (PNX) peptide is linked to the control of reproduction, food intake, stress, and inflammation. However, little is known about what regulates its gene and protein expression, information that is critical to understand the physiological role of PNX. In this review, we summarize what is known about the transcriptional control of Pnx and its receptor Gpr173. A main function of PNX is as a positive regulator of the hypothalamic-pituitary-gonadal axis, but there is a lack of research on its control by reproductive hormones and peptides. PNX is also associated with food intake, and its expression is linked to feeding status, fatty acids, and glucose. It is influenced by environmental and hormonal-induced stress. The regulation of Pnx in most contexts remains an enigma, in part due to conflicting and negative results. An extensive analysis of the response of the Pnx gene to factors related to reproduction, metabolism, stress, and inflammation is required. Analysis of the Pnx promoter and epigenetic regulation must be considered to understand how this level of control contributes to its pleiotropic effects. PNX is now linked to a broad range of functions, but more research on its gene regulation is required to understand its place in overall physiology and therapeutic potential.

Nesfatin-1 stimulates the hypothalamus-pituitary-interrenal axis hormones in goldfish

Stress in vertebrates is mediated by the hypothalamus-pituitary-adrenal (in mammals)/interrenal (in fish) (HPA/I) axis, which produces the corticotropin-releasing factor (CRF), adrenocorticotropic hormone (ACTH), and corticosteroids, respectively. Nesfatin-1, a novel anorexigenic peptide encoded in the precursor nucleobindin-2 (NUCB2), is increasingly acknowledged as a peptide that influences the stress axis in mammals. The primary aim of this study was to characterize the putative effects of nesfatin-1 on the fish HPI axis, using goldfish (Carassius auratus) as an animal model. Our results demonstrated that nucb2/nesfatin-1 transcript abundance was detected in the HPI tissues of goldfish, with most abundant expression in the pituitary. NUCB2/nesfatin-1-like immunoreactivity was found in the goldfish hypothalamus, pituitary, and interrenal cells of the head kidney. GPCR12, a putative receptor for nesfatin-1, was also detected in the pituitary and interrenal cells. NUCB2/nesfatin-1-like immunoreactivity was observed in ACTH-expressing pituitary corticotrophs. Acute netting and restraint stress upregulated nucb2/nesfatin-1 mRNA levels in the forebrain, hypothalamus, and pituitary, as well as crf and crf-r1 expression in the forebrain and hypothalamus. Intraperitoneal and intracerebroventricular administration of nesfatin-1 increased cortisol release and hypothalamic crf mRNA levels, respectively. Finally, we found that nesfatin-1 significantly stimulated ACTH secretion from dispersed pituitary cells in vitro. Collectively, our data provide the first evidence showing that nesfatin-1 is a stress responsive peptide, which modulates the stress axis hormones in fish.

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.

Role of the Novel Peptide Phoenixin in Stress Response and Possible Interactions with Nesfatin-1

The novel peptide phoenixin was shown to be involved in several physiological processes ranging from reproduction to food intake. Interest in this protein has steadily increased over the last few years and its known implications have become much broader, playing a role in glucose homeostasis, anxiety, nociception, and pruritus. Phoenixin is expressed in a multitude of organs such as the small intestine, pancreas, and in the hypothalamus, as well as several other brain nuclei influencing numerous physiological functions. Its highly conserved amino-acid sequence amongst species leads to the assumption, that phoenixin might be involved in essential physiological functions. Its co-expression and opposing functionality to the extensively studied peptide nesfatin-1 has given rise to the idea of a possible counterbalancing role. Several recent publications focused on phoenixin’s role in stress reactions, namely restraint stress and lipopolysaccharide-induced inflammation response, in which also nesfatin-1 is known to be altered. This review provides an overview on the phoenixins and nesfatin-1 properties and putative effects, and especially highlights the recent developments on their role and interaction in the response to response.

Phoenixin: More than Reproductive Peptide

Phoenixin (PNX) neuropeptide is a cleaved product of the Smim20 protein. Its most common isoforms are the 14- and 20-amino acid peptides. The biological functions of PNX are mediated via the activation of the GPR173 receptor. PNX plays an important role in the central nervous system (CNS) and in the female reproductive system where it potentiates LH secretion and controls the estrus cycle. Moreover, it stimulates oocyte maturation and increases the number of ovulated oocytes. Nevertheless, PNX not only regulates the reproduction system but also exerts anxiolytic, anti-inflammatory, and cell-protective effects. Furthermore, it is involved in behavior, food intake, sensory perception, memory, and energy metabolism. Outside the CNS, PNX exerts its effects on the heart, ovaries, adipose tissue, and pancreatic islets. This review presents all the currently available studies demonstrating the pleiotropic effects of PNX.