Developmental expression and distribution of nesfatin-1/NUCB2 in the canine digestive system

"Sibling" battle or harmony: crosstalk between nesfatin-1 and ghrelin

Ghrelin was first identified as an endogenous ligand of the growth hormone secretagogue receptor (GHSR) in 1999, with the function of stimulating the release of growth hormone (GH), while nesfatin-1 was identified in 2006. Both peptides are secreted by the same kind of endocrine cells, X/A-like cells in the stomach. Compared with ghrelin, nesfatin-1 exerts opposite effects on energy metabolism, glucose metabolism, gastrointestinal functions and regulation of blood pressure, but exerts similar effects on anti-inflammation and neuroprotection. Up to now, nesfatin-1 remains as an orphan ligand because its receptor has not been identified. Several studies have shown the effects of nesfatin-1 are dependent on the receptor of ghrelin. We herein compare the effects of nesfatin-1 and ghrelin in several aspects and explore the possibility of their interactions.

Minireview: Peripheral Nesfatin-1 in Regulation of the Gut Activity—15 Years since the Discovery

Simple Summary

Nesfatin-1 is a newly identified molecule derived from the precursor protein NEFA/nucleobindin2. In this minireview we analyzed the research on the nesfatin-1 localization in the gastrointestinal tract of the mammals. We also referred to the effects of the protein on disorders in the gastrointestinal tract.

Abstract

Nesfatin-1, discovered in 2006, is an anorexigenic molecule derived from the precursor protein NEFA/nucleobindin2. It is generally postulated that this molecule acts through a specific G protein-coupled receptor, as yet unidentified. Research conducted over the last 15 years has revealed both central and peripheral actions of nesfatin-1. Given its major central role, studies determining its inhibitory effect on food intake seem to be of major scientific interest. However, in recent years a number of experiments have found that peripheral organs, including those of the gastrointestinal tract (GIT), may also be a source (possibly even the predominant source) of nesfatin-1. This mini-review aimed to summarize the current state of knowledge regarding the expression and immunoreactivity of nesfatin-1 and its possible involvement (both physiological and pathological) in the mammalian GIT. Research thus far has shown very promising abilities of nesfatin-1 to restore the balance between pro-oxidants and antioxidants, to interplay with the gut microbiota, and to alter the structure of the intestinal barrier. This necessitates more extensive research on the peripheral actions of this molecule. More in-depth knowledge of such mechanisms (especially those leading to anti-inflammatory and anti-apoptotic effects) is important for a better understanding of the involvement of nefatin-1 in GIT pathophysiological conditions and/or for future therapeutic approaches.

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.

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.

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.

NUCB2/nesfatin-1 - Inhibitory effects on food intake, body weight and metabolism

Since its discovery in 2006 by Oh-I and colleagues, NUCB2/nesfatin-1 encoded by nucleobindin-2 (NUCB2) has drawn sustained attention as reflected in over 500 publications. Among those, more than half focused on the alterations of food intake, body weight and metabolism (glucose, fat) induced by nesfatin-1 and/or NUCB2/nesfatin-1. In the current review we discuss the existing literature focusing on NUCB2/nesfatin-1's influence on food intake, body weight and glucose as well as fat metabolism and highlight gaps in knowledge.

17Beta-Estradiol Regulates NUCB2/ Nesfatin-1 Expression in Mouse Oviduct

NUCB2/nesfatin-1 known to regulate appetite and energy homeostasis is expressed not only in the hypothalamus, but also in various organs and tissues. Our previous reports also demonstrated that NUCB2/nesfatin-1 was expressed in the reproductive organs, including the ovaries, uterus, and testes of mice. However, it is yet known whether NUCB2/nesfatin-1 is expressed in the oviduct and how its expression is regulated. Therefore, we investigated the expression of NUCB2/nesfatin-1 in the oviduct and its expression is regulated by gonadotropin. Immunohistochemical staining results showed that nesfatin-1 protein was localized in epithelial cells of the oviduct. As a result of quantitative real-time PCR (qRT-PCR) and Western blot, NUCB2/nesfatin-1 was detected strongly in the oviducts. During the estrus cycle, NUCB2/nesfatin-1 expression in the oviducts was markedly higher in the proestrus stage than in other estrus stages. In order to elucidate whether the expression of NUCB2 mRNA is controlled by the gonadotropins, we injected PMSG and hCG and measured NUCB2 mRNA level in the oviduct after injection. Its level was increased in the oviduct after PMSG injection, but no significant change after hCG injection. In addition, NUCB2 mRNA levels were markedly reduced after ovariectomy, while recovered after 17β-estradiol (E2) injection, but not by progesterone (P4). This study demonstrated that NUCB2/nesfatin-1 is highly expressed in the oviduct of mouse and its expression is regulated by E2 secreted by the ovaries. These results suggest that NUCB2/nesfatin-1 expressed by the oviduct may affect the function of the oviduct regulated by the ovaries.

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.

Potential physiological involvement of nesfatin-1 in regulating swine granulosa cell functions

Nesfatin-1 has recently been indicated as a pleiotropic molecule that is primarily involved in the metabolic regulation of reproductive functions acting at hypothalamic level. The aim of this study was to explore the local action of nesfatin-1 in swine ovarian follicles. Nucleobindin 2 (NUCB2) was verified using real-time quantitative polymerase chain reaction in swine granulosa cells from different sized follicles and nesfatin-1 was localised by immunohistochemistry in sections of the whole porcine ovary. The effects of different concentrations of nesfatin-1 on cell growth, steroidogenesis and the redox status of granulosa cells were determined invitro. In addition, the effects of nesfatin-1 were evaluated in an angiogenesis bioassay because vessel growth is essential for ovarian follicle function. Immunohistochemistry revealed intense positivity for nesfatin-1 in swine granulosa cells in follicles at all developmental stages. Expression of the gene encoding the precursor protein NUCB2 was higher in granulosa cells from large rather than from medium and small follicles. Further, nesfatin-1 stimulated cell proliferation and progesterone production and interfered with redox status by modifying nitric oxide production and non-enzyme scavenging activity in granulosa cells from large follicles. Moreover, nesfatin-1 exhibited a stimulatory effect on angiogenesis. This study demonstrates, for the first time, that nesfatin-1 is physiologically present in the swine ovarian follicle, where it may impair granulosa cell functions.

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.

Tissue-specific expression and circulating concentrations of nesfatin-1 in domestic animals

Nesfatin-1 is a naturally occurring 82-amino acid protein encoded in the precursor nucleobindin-2 (NUCB2) and has been implicated in multiple physiological functions, including food intake and blood glucose regulation. This study aimed to characterize nesfatin-1 in domestic species, especially cats (Felis catus), dogs (Canis lupus familiaris), and pigs (Sus scrofa). Our in silico analysis demonstrated that the NUCB2/nesfatin-1 amino acid sequence, especially the bioactive core region of the peptide, is very highly conserved (more than 90% identity) in domestic animals. Expression of mRNAs encoding NUCB2/nesfatin-1 was detected in the cat, dog, and pig stomach and pancreas. Immunohistochemistry revealed the presence of nesfatin-1 in the gastric mucosa of the stomach of dogs, cats, and pigs, and in the pancreatic islet β-cells of dogs and pigs. No nesfatin-1 immunoreactivity was found in the cat pancreas. Nesfatin-1 was detected in the serum of dog, cat, pig, bison, cow, horse, sheep, and chicken. Circulating nesfatin-1 in male and female dogs remained unchanged at 60 min after glucose administration, suggesting a lack of meal responsiveness in nesfatin-1 secretion in this species. The presence of nesfatin-1 in the gastric and endocrine pancreatic tissues suggests possible roles for this peptide in the metabolism of domestic animals. Future research should focus on elucidating the species-specific functions and mechanisms of action of nesfatin-1 in health and disease of domestic animals.

Study of the effects of nesfatin-1 on gastric function in obese rats

AIM

To investigate the effects of nesfatin-1 on gastric function in obese rats.

METHODS

The obese rat model was induced by a high-fat diet. The gastric emptying rate and gastric acid secretory capacity of the rats were determined after treatment with different drug concentrations of nesfatin-1 and administration routes. Based on this, the expression of H+/K+-ATPase was measured using RT-PCR and western blot to preliminarily explore the mechanism of gastric acid secretion changes.

RESULTS

Body weight, body length, and Lee’s index of the rats significantly increased in the high-fat diet-induced obese rat model. Two hours after lateral intracerebroventricular injection of nesfatin-1, the gastric emptying rate and gastric acid secretory capacity of rats decreased. Four hours after injection, both were restored to normal levels. In addition, the expression of H+/K+-ATPase decreased and moved in line with changes in gastric acid secretory capacity. This in vivo experiment revealed that intracerebroventricular injection of nesfatin-1, rather than intravenous injection, could suppress gastric function in obese rats. Moreover, its effect on the gastric emptying and gastric acid secretory capacity of rats is dose-dependent within a certain period of time.

CONCLUSION

Through this research, we provide a theoretical basis for further studies on nesfatin-1, a potential anti-obesity drug.

Testosterone Regulates NUCB2 mRNA Expression in Male Mouse Hypothalamus and Pituitary Gland

Nesfatin-1/NUCB2 is known to take part in the control of the appetite and energy metabolism. Recently, many reports have shown nesfatin-1/NUCB2 expression and function in various organs. We previously demonstrated that nesfatin-1/NUCB2 expression level is higher in the pituitary gland compared to other organs and its expression is regulated by 17β-estradiol and progesterone secreted from the ovary. However, currently no data exist on the expression of nesfatin-1/NUCB2 and its regulation mechanism in the pituitary of male mouse. Therefore, we examined whether nesfatin-1/NUCB2 is expressed in the male mouse pituitary and if its expression is regulated by testosterone. As a result of PCR and western blotting, we found that a large amount of nesfatin-1/NUCB2 was expressed in the pituitary and hypothalamus. The NUCB2 mRNA expression level in the pituitary was decreased after castration, but not in the hypothalamus. In addition, its mRNA expression level in the pituitary was increased after testosterone treatment in the castrated mice, whereas, the expression level in the hypothalamus was significantly decreased after the treatment with testosterone. The in vitro experiment to elucidate the direct effect of testosterone on NUCB2 mRNA expression showed that NUCB2 mRNA expression was significantly decreased with testosterone in cultured hypothalamus tissue, but increased with testosterone in cultured pituitary gland. The present study demonstrated that nesfatin-1/NUCB2 was highly expressed in the male mouse pituitary and was regulated by testosterone. This data suggests that reproductive-endocrine regulation through hypothalamus-pituitary-testis axis may contribute to NUCB2 mRNA expression in the mouse hypothalamus and pituitary gland.

Expression and regulation of peripheral NUCB2/nesfatin-1

Nesfatin-1, an 82 amino acid peptide was discovered in 2006 in the rat hypothalamus and described as a centrally acting anorexigenic peptide. Besides its central expression and actions, NUCB2/nesfatin-1 has been subsequently described to be predominantly expressed in the periphery and to exert several peripheral effects. The current review focuses on the expression sites of NUCB2/nesfatin-1 in peripheral tissues of different species and its regulation by nutrition, body weight and various other parameters such as fetal development and sex.