Nesfatin-1-like peptide is a novel metabolic factor that suppresses feeding, and regulates whole-body energy homeostasis in male Wistar rats

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.

Suppressive action of nesfatin-1 and nesfatin-1-like peptide on cortisol synthesis in human adrenal cortex cells

Nucleobindin-derived peptides, nesfatin-1 [NESF-1] and nesfatin-1-like-peptide [NLP] have diverse roles in endocrine and metabolic regulation. While both peptides showed a stimulatory effect on the synthesis of proopiomelanocortin (POMC), the adrenocorticotropic hormone (ACTH) precursor in mouse corticotrophs, whether NESF-1 and NLP have any direct effect on glucocorticoid [GC] synthesis in the adrenal cortex remains unknown. The main aim of this study was to determine if NESF-1 and/or NLP act directly on adrenal cortex cells to regulate cortisol synthesis in vitro. Whether NLP injection affects stress-hormone gene expression in the adrenal gland and pituitary in vivo in mice was also assessed. In addition, cortisol synthetic pathway in Nucb1 knockout mice was studied. Human adrenal cortical [H295R] cells showed immunoreactivity for both NUCB1/NLP and NUCB2/NESF-1. NLP and NESF-1 decreased the abundance of steroidogenic enzyme mRNAs, and cortisol synthesis and release through the AC/PKA/CREB pathway in H295R cells. Similarly, intraperitoneal injection of NLP in mice decreased the expression of enzymes involved in glucocorticoid (GC) synthesis in the adrenal gland while increasing the expression of Pomc, Pcsk1 and Crhr1 in the pituitary. Moreover, the melanocortin 2 receptor (Mc2r) mRNA level was enhanced in the adrenal gland samples of NLP injected mice. However, the global genetic disruption in Nucb1 did not affect most steroidogenic enzyme mRNAs, and Pomc, Pcsk2 and Crhr1 mRNAs in mice adrenal gland and pituitary gland, respectively. Collectively, these data provide the first evidence for a direct inhibition of cortisol synthesis and secretion by NLP and NESF-1. NUCB peptides might still elicit a net stimulatory effect on GC synthesis and secretion through their positive effects on ACTH-MC2R pathway in the pituitary.

Calnuc-derived nesfatin-1-like peptide is an activator of tumor cell proliferation and migration

Calnuc (nucleobindin-1, nucb1) is a Ca2+ -binding protein involved in the etiology of many human diseases. To understand the functions of calnuc, we have identified a nesfatin-1-like peptide (NLP) in its N terminus that is proteolyzed by a convertase enzyme in the secretory granules of cells. Mutational studies confirm the presence of a proteolytic cleavage site for proprotein convertase subtilisin/kexin type 1 (PCSK1). We demonstrate that NLP regulates Gαq-mediated intracellular Ca2+ dynamics, likely via a G-protein-coupled receptor. NLP treatment to carcinoma cell lines (SCC131 cells) promotes the expression of regulators of cell cycle, proliferation, and clonogenicity by the AKT/mTOR pathway. NLP is causative of augmented migration and epithelial-mesenchymal transition (EMT), illustrating its metastatic propensity and establishing its tumor promotion ability.

Tissue-Specific Modulation of Gluco- and Growth-Regulatory Factor Abundance by Nesfatin-1 and Nesfatin-1-like Peptide in Goldfish

Nesfatin-1 and nesfatin-1-like peptide (Nlp) are derived from precursors nucleobindin-2 and -1, two calcium and DNA binding proteins, respectively. Both peptides exhibit hormone-like actions in mammals and fish. These functions include insulinotropic effects of nesfatin-1 and Nlp seen in mice and their growth hormone suppressive actions reported in goldfish. We hypothesized that nesfatin-1 and Nlp are insulin stimulatory (in adipose tissue) and modulate growth hormone and insulin-like growth factors and glucose transporters in goldfish. To test this, goldfish were intraperitoneally injected with either nesfatin-1 or Nlp (50 ng/g BW) or saline alone (control) and sampled at one-hour post-injection (in vivo study). In a separate study, tissue samples were collected and were incubated with either nesfatin-1 or Nlp for one or six hours (in vitro study). Transcript (mRNA) abundance data from the adipose tissue suggest that both nesfatin-1 and Nlp significantly upregulate the abundance of preproinsulin, insulin receptors, and pcsk1 and pcsk2 mRNAs. Meanwhile, the abundance of preproglucagon mRNA in the adipose tissue was significantly downregulated in both in vivo and in vitro studies. These results agree with the insulinotropic and glucagonostatic roles for nesfatin-1 and Nlp reported in rodents. The transcript abundance of growth regulators (igf1, igf2a, and ghra) and glucose transporters (slc2a2 and slc5a1) were upregulated in the muscle, while an opposite effect on these mRNAs was found in the liver of goldfish following nesfatin-1 and Nlp administration. Our results suggest that both nesfatin-1 and Nlp have tissue-specific regulatory roles on growth and glucoregulatory elements in the liver and muscle of goldfish. This agrees with our previous studies that showed a suppressive action of nesfatin-1 on growth hormone in goldfish liver. The results presented here provide strong supportive/confirmatory evidence for tissue-specific insulinotropic and gluco- and growth-regulatory actions of nesfatin-1 and Nlp in goldfish.

NESFATIN-1 ACTIVITY IN THE BLOOD SERUM IN PATIENTS WITH CHRONIC HEART FAILURE OF ISCHEMIC ORIGIN AGAINST THE BACKGROUND OF TYPE 2 DIABETES MELLITUS AND OBESITY

OBJECTIVE

The aim: To study the nesfatin-1 activity in the blood serum of patients with chronic heart failure (CHF) of ischemic origin against the background of such metabolic disorders as type 2 diabetes mellitus (T2DM) and obesity.

PATIENTS AND METHODS

Materials and methods: 154 patients with CHF were examined, and divided into 4 groups, according to the presence of metabolic disorders. Group 1 included patients with CHF on the background of coronary heart disease (CHD) and T2DM and obesity (n=42). The second group consisted of patients with heart failure on the background of CHD with concomitant T2DM (n=46), the third group - with concomitant obesity (n=36), the fourth group was formed from patients with signs of heart failure of ischemic origin without metabolic disorders (n=30). The control group (CG) included 30 practically healthy persons of comparable age.

RESULTS

Results: The mean level of serum nesfatin-1 was 1.64±0.27 ng/mL in the СHF group, 0.342±0.19 ng/mL in the CHF + T2DM + obesity group, 1.06±0.36 ng/ mL in the obese + CHF group, 0.96±0.27 ng/mL in the CHF + T2DM group and 2.98±0.38 ng/mL in the CG. Significant correlation was found between the serum nesfatin-1 level and BMI (r=-0.34, p<0.05), HOMA (r=-0.54, p<0.05), insulin (r=-0.41, p<0.05). No significant correlation was found between the serum nesfatin-1 level and blood glucose level (r=0.13, p=0.65).

CONCLUSION

Conclusions: Thus, nesfatin-1 may play a significant role in the pathogenesis of both weight-related abnormalities and type 2 diabetes mellitus in patients with chronic heart failure of ischemic origin.

Nesfatin-1-like peptide is a negative regulator of cardiovascular functions in zebrafish and goldfish

Nucleobindins (NUCB1 and NUCB2) were originally identified as calcium and DNA binding proteins. Nesfatin-1 (NEFA/nucleobindin-2-Encoded Satiety and Fat-Influencing proteiN-1) is an 82 amino acid anorexigenic peptide encoded in the N-terminal region of NUCB2. We have shown that nesfatin-1 is a cardiosuppressor in zebrafish. Both NUCB1 and NUCB2 possess a -very highly conserved bioactive core. It was found that a nesfatin-1-like peptide (NLP) encoded in NUCB1 suppresses food intake in fish. In this research, we investigated whether NLP has nesfatin-1-like effects on cardiovascular functions. NUCB1/NLP-like immunoreactivity was found in the atrium and ventricle of the heart and skeletal muscle of zebrafish. Intraperitoneal injection (IP) of either zebrafish NLP or rat NLP suppressed cardiac functions in both zebrafish and goldfish. Irisin and RyR1b mRNA expression was downregulated by NLP in zebrafish cardiac and skeletal muscles. However, cardiac ATP2a2 mRNA expression was elevated after NLP injection. Administration of scrambled NLP did not affect irisin, RyR1b or ATP2a2 mRNA expression in zebrafish. Together, these results implicate NLP as a suppressor of cardiovascular physiology in zebrafish and goldfish.

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 and Nesfatin-1-like peptide suppress basal and TRH-Induced expression of prolactin and prolactin regulatory element-binding protein mRNAs in rat GH3 somatolactotrophs

Prolactin (PRL), mainly synthesized and secreted by the lactotrophs and somatolactotrophs of the anterior pituitary, is a pleiotropic hormone that regulates lactation. In the last decade, nesfatin-1 (NESF) and NESF-like peptide (NLP), encoded in nucleobindin 1 and 2 (NUCB1 and NUCB2), respectively, were characterized as metabolic factors with a potential role in the control of pituitary hormones. We hypothesized that NUCBs and their encoded peptides (NESF and NLP) suppress PRL transcription in the pituitary. The main objective of this research was to determine whether exogenous NESF and NLP, and/or endogenous NUCB1 and NUCB2 regulate the expression of prl and preb mRNAs. Using immortalized rat somatolactotrophs (GH3 cells), dose-response studies were performed to test whether NESF and NLP affect prl and preb. Moreover, the ability of these peptides to modulate the effects of the PRL stimulator thyrotropin releasing hormone (TRH) was studied. Besides, the effects of siRNA-mediated knockdown of endogenous NUCBs on prl and preb mRNAs were determined. NESF and NLP reduced the transcription of prl and preb in GH3 cells. Both NESF and NLP also prevented the stimulatory effects of TRH prl and preb expression. The knockdown of endogenous NUCB1 attenuates both basal prl and TRH-induced expression of prl and preb, while the silencing of NUCBs did not affect the actions of exogenous NESF or NLP. Overall, this work reveals that NUCBs and encoded-peptides are novel regulators of PRL. Future research should test whether the effects observed here in GH3 cells are preserved both in vivo and at the post-transcriptional level.

The Complex World of Regulation of Pituitary Growth Hormone Secretion: The Role of Ghrelin, Klotho, and Nesfatins in It

The classic concept of how pituitary GH is regulated by somatostatin and GHRH has changed in recent years, following the discovery of peripheral hormones involved in the regulation of energy homeostasis and mineral homeostasis. These hormones are ghrelin, nesfatins, and klotho. Ghrelin is an orexigenic hormone, released primarily by the gastric mucosa, although it is widely expressed in many different tissues, including the central nervous system and the pituitary. To be active, ghrelin must bind to an n-octanoyl group (n = 8, generally) on serine 3, forming acyl ghrelin which can then bind and activate a G-protein-coupled receptor leading to phospholipase C activation that induces the formation of inositol 1,4,5-triphosphate and diacylglycerol that produce an increase in cytosolic calcium that allows the release of GH. In addition to its direct action on somatotrophs, ghrelin co-localizes with GHRH in several neurons, facilitating its release by inhibiting somatostatin, and acts synergistically with GHRH stimulating the synthesis and secretion of pituitary GH. Gastric ghrelin production declines with age, as does GH. Klotho is an anti-aging agent, produced mainly in the kidneys, whose soluble circulating form directly induces GH secretion through the activation of ERK1/2 and inhibits the inhibitory effect that IGF-I exerts on GH. Children and adults with untreated GH-deficiency show reduced plasma levels of klotho, but treatment with GH restores them to normal values. Deletions or mutations of the Klotho gene affect GH production. Nesfatins 1 and 2 are satiety hormones, they inhibit food intake. They have been found in GH3 cell cultures where they significantly reduce the expression of gh mRNA and that of pituitary-specific positive transcription factor 1, consequently acting as inhibitors of GH production. This is a consequence of the down-regulation of the cAMP/PKA/CREB signaling pathway. Interestingly, nesfatins eliminate the strong positive effect that ghrelin has on GH synthesis and secretion. Throughout this review, we will attempt to broadly analyze the role of these hormones in the complex world of GH regulation, a world in which these hormones already play a very important role.

Nesfatin-1 and nesfatin-1-like peptide suppress growth hormone synthesis via the AC/PKA/CREB pathway in mammalian somatotrophs

Nesfatin-1 (NESF) and NESF-like peptide (NLP), encoded in nucleobindin 2 and 1 (NUCB2 and NUCB1), respectively, are orphan ligands and metabolic factors. We hypothesized that NESF and NLP suppress growth hormone (GH) synthesis, and aimed to determine whether mammalian somatotrophs are a source and site of action of these peptides. Using immortalized rat somatotrophs (GH3 cells), NUCB expression was determined by qPCR, immunofluorescence and Western blot. NESF and NLP binding to GH3 cells was tested using fluorescence imaging. Both time- and concentration-dependent studies were performed to test whether NESF and NLP affect GH. Moreover, the ability of these peptides to modulate the effects of ghrelin, and cell-signaling pathways were studied. GH3 cells express NUCB mRNAs and protein. Labeled NESF and NLP bind to the surface of GH3 cells, and incubation with either NESF or NLP decreased GH mRNA and protein expression, downregulated pit-1 mRNA, and blocked the GH stimulatory effects of ghrelin. Pre-incubation with either of these peptides reduced CREB phosphorylation by an AC-activator, but not when PKA was directly activated by a cAMP analog. Our results indicate that rat somatotrophs are a source of NUCBs, and that NESF and NLP downregulate GH synthesis through the AC/PKA/CREB signaling pathway.

Nesfatin-1-like peptide suppresses hypothalamo-pituitary-gonadal mRNAs, gonadal steroidogenesis, and oocyte maturation in fish†

Nucleobindin (Nucb)-1 and Nucb2 are DNA and Ca2+ binding proteins with multiple functions in vertebrates. Prohormone convertase-mediated processing of Nucb2 results in the production of biologically active nesfatin-1. Nesfatin-1 is involved in the regulation of reproduction in many vertebrates, including fish. Our lab originally reported a nesfatin-1-like peptide (Nlp) encoded in Nucb1 that exhibits nesfatin-1-like metabolic effects. We hypothesized that Nlp has a suppressive role in the reproductive physiology of fish. In this research, whether Nlp regulates reproductive hormones and oocyte maturation in fish were determined. Single intraperitoneal (IP) injection of goldfish Nlp (50 ng/g body weight) suppressed salmon and chicken gonadotropin-releasing hormone (sgnrh and cgnrh2), gonadotropin-inhibiting hormone (gnih) and its receptor (gnihr), and kisspeptin and brain aromatase mRNA expression in the hypothalamus of both male and female goldfish. In the pituitary, Nlp decreased mRNAs encoding lhb, fshb and kisspeptin and its receptor, while a significant increase in gnih and gnihr was observed. In the gonads, lh (only in male fish) and fsh receptor mRNAs were also significantly downregulated in Nlp-injected fish. Sex-specific modulation of gnih, gnihr, and kisspeptin system in the gonads was also observed. Nlp decreased sex steroidogenic enzyme encoding mRNAs and circulating levels of testosterone and estradiol. In addition, incubation of zebrafish ovarian follicles with Nlp resulted in a reduction in oocyte maturation. These results provide evidence for a robust role for Nlp in regulating reproductive hormones in goldfish and oocyte maturation in zebrafish, and these effects resemble that of nesfatin-1.

Effects of feeding status on nucb1 and nucb2A mRNA expression in the hypothalamus of Schizothorax davidi

NUCB1 and NUCB2, two novel nucleobindins, have attracted extensive attention for their role in the appetite regulation in mammals. However, little is known about the appetite regulation of NUCB1 and NUCB2 in fish species. Therefore, we investigated the role of these peptides in the regulation of feeding in Schizothorax davidi (S. davidi). In this study, full-length cDNA sequences of nucb1 and nucb2A of S. davidi were obtained for the first time. Additionally, the tissue distribution and the effects of different energy status on nucb1 and nucb2A mRNAs abundance were assessed, showing that nucb1 and nucb2A are widely distributed in 18 detected tissues, with the highest expression in the cerebellum. The abundances of nucb1 and nucb2A increased in the hypothalamus at 1 h and 3 h post-feeding. Furthermore, fasting and re-feeding experiments showed that the expressions of nucb1 and nucb2A in hypothalamus significantly decreased after fasting for 7 days, and returned to the control level after re-feeding for 3 or 5 days. In conclusion, the present study suggests that both NUCB1 and NUCB2A are involved in the short-term and long-term appetite regulation, as an anorexigenic factor, in S. davidi. These results can provide a basis for further investigation into the appetite regulatory role of NUCB family in teleost.

Fish as models for understanding the vertebrate endocrine regulation of feeding and weight

The frequencies of eating disorders and obesity have increased worldwide in recent years. Their pathophysiologies are still unclear, but recent evidence suggests that they might be related to changes in endocrine and neural factors that regulate feeding and energy homeostasis. In order to develop efficient therapeutic drugs, a more thorough knowledge of the neuronal circuits and mechanisms involved is needed. Although to date, rodents have mostly been used models in the area of neuroscience and neuroendocrinology, an increasing number of studies use non-mammalian vertebrates, in particular fish, as model systems. Fish present several advantages over mammalian models and they share genetic and physiological homology to mammals with close similarities in the mechanisms involved in the neural and endocrine regulation of appetite. This review briefly describes the regulation of feeding in two model species, goldfish and zebrafish, how this regulation compares to that in mammals, and how these fish could be used for studies on endocrine regulation of eating and weight and its dysregulations.

Nucleobindins and encoded peptides: From cell signaling to physiology

Nucleobindins (NUCBs) are DNA and calcium binding, secreted proteins with various signaling functions. Two NUCBs, nucleobindin-1 (NUCB1) and nucleobindin-2 (NUCB2), were discovered during the 1990s. These two peptides are shown to have diverse functions, including the regulation of inflammation and bone formation, among others. In 2006, Oh-I and colleagues discovered that three peptides encoded within the NUCB2 could be processed by prohormone convertases. These peptides were named nesfatin-1, 2 and 3, mainly due to the satiety and fat influencing properties of nesfatin-1. However, it was found that nesfatin-2 and -3 have no such effects. Nesfatin-1, especially its mid-segment, is very highly conserved across vertebrates. Although the receptor(s) that mediate nesfatin-1 effects are currently unknown, it is now considered an endogenous peptide with multiple functions, affecting central and peripheral tissues to regulate metabolism, reproduction, endocrine and other functions. We recently identified a nesfatin-1-like peptide (NLP) encoded within the NUCB1. Like nesfatin-1, NLP suppressed feed intake in mice and fish, and stimulated insulin secretion from pancreatic beta cells. There is considerable evidence available to indicate that nucleobindins and its encoded peptides are multifunctional regulators of cell biology and whole animal physiology. This review aims to briefly discuss the structure, distribution, functions and mechanism of action nucleobindins and encoded peptides.