Expression of Nesfatin-1/NUCB2 in Fetal, Neonatal and Adult Mice

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.

Nesfatin-1 protects the reproductive health of male Sprague Dawley rats exposed to blue and white LED lights

There is little information on the effects of exposure to light emitting diode (LED) illumination on the welfare of laboratory animals. Nesfatin-1, a satiety-regulation peptide present in various tissues, is found in the central nervous system and participates in the stress response. The present study investigated whether exposure to blue and white LED lights for 14 weeks affected growth and reproductive, biochemical and histopathological parameters in male Sprague Dawley (SD) rats as well as whether subcutaneous (SC) injection of nesfatin-1 (0.5 mg/kg bodyweight) in the last two weeks of the experimental period alleviated these effects. Forty male SD rats (21 days of age) were randomly allotted to 6 groups. The animals were exposed to routine fluorescent light (the control [C] and control + sesame oil [CS] groups) or blue/white LEDs (the blue-LED and white-LED groups), accompanied by nesfatin-1 administration (the blue-LED-N1 and white-LED-N1 groups). White-LED rats had significantly higher testis weights (p < 0.05) than control and blue-LED rats. Serum melatonin levels were significantly lower in blue-LED rats, but nesfatin-1 injection rescued melatonin levels in blue-LED-N1 rats (p < 0.05). Blue-LED rats showed the highest serum nesfatin-1 levels, but nesfatin-1 injection decreased nesfatin-1 levels in blue-LED-N1 rats (p < 0.0001). Blue-LED rats showed a significant reduction in sperm motility compared to the other groups (p < 0.0001). White and blue LED exposure caused significant negative histopathological changes in the testes, but nesfatin-1 administration reduced edema in the intertubular spaces, hyperemia in the interstitial cells, degeneration of spermatocytes and thinning of the tubular wall in the testicular tissues; these restorative effects were larger in blue-LED-N1 rats than white-LED-N1 rats. Blue and white LED exposures had negative effects on melatonin levels, testis weights and tissue health. Nesfatin-1 alleviated some of the negative effects of LED lighting.

Enteroendocrine cells and gut hormones as potential targets in the crossroad of the gut-kidney axis communication

Recent studies suggest that disruptions in intestinal homeostasis, such as changes in gut microbiota composition, infection, and inflammatory-related gut diseases, can be associated with kidney diseases. For instance, genomic investigations highlight how susceptibility genes linked to IgA nephropathy are also correlated with the risk of inflammatory bowel disease. Conversely, investigations demonstrate that the use of short-chain fatty acids, produced through fermentation by intestinal bacteria, protects kidney function in models of acute and chronic kidney diseases. Thus, the dialogue between the gut and kidney seems to be crucial in maintaining their proper function, although the factors governing this crosstalk are still emerging as the field evolves. In recent years, a series of studies have highlighted the significance of enteroendocrine cells (EECs) which are part of the secretory lineage of the gut epithelial cells, as important components in gut-kidney crosstalk. EECs are distributed throughout the epithelial layer and release more than 20 hormones in response to microenvironment stimuli. Interestingly, some of these hormones and/or their pathways such as Glucagon-Like Peptide 1 (GLP-1), GLP-2, gastrin, and somatostatin have been shown to exert renoprotective effects. Therefore, the present review explores the role of EECs and their hormones as regulators of gut-kidney crosstalk and their potential impact on kidney diseases. This comprehensive exploration underscores the substantial contribution of EEC hormones in mediating gut-kidney communication and their promising potential for the treatment of kidney diseases.

Nesfatin-1, a novel energy-regulating peptide, alleviates pulmonary fibrosis by blocking TGF-β1/Smad pathway in an AMPKα-dependent manner

Pulmonary fibrosis is a chronic progressive disease which steadily causes a critical public health concern. Nesfatin-1, a novel energy-regulating peptide discovered in 2006, could increase the level of AMPK phosphorylation. Previous studies have unveiled that Nesfatin-1 possessed many pharmacological effects including anti-inflammation, anti-oxidative stress, anti-fibrosis, and the regulation of lipid metabolism. Here, we investigated the impact of Nesfatin-1 on pulmonary fibrosis. Male C57BL/6J mice were intraperitoneally injected with Nesfatin-1 (10 μg·kg^-1·day^-1) for 21 days since mice were intratracheally administrated with bleomycin (BLM) (2 U/kg). Primary murine lung fibroblasts were stimulated with TGF-β1 (10 ng/ml) for 48 h. The results showed that Nesfatin-1 treatment significantly improved pulmonary function and decreased the production of collagen in BLM-treated mice. Meantime, Nesfatin-1 treatment also inhibited oxidative stress and inflammation in lung tissues from BLM-treated mice. Mechanically, Nesfatin-1 blocked the activation of TGF-β1/Smad2/3 signaling pathway in lung tissues challenged with BLM. In addition, we found that Nesfatin-1 enhanced the phosphorylation of AMPKα during pulmonary fibrosis. However, pharmacological inhibition or genetic deletion of AMPKα could both offset the pulmonary protection mediated by Nesfatin-1 during pulmonary fibrosis. Our experimental results firstly show Nesfatin-1 might serve as a novel treatment or adjuvant against pulmonary fibrosis by blocking TGF-β1/Smad pathway in an AMPKα-dependent manner.

NUCB2: roles in physiology and pathology

Nucleobindin2 (NUCB2) is a member of nucleobindin family which was first found in the nucleus of the hypothalamus, and had a relationship in diet and energy homeostasis. Its location in normal tissues such as stomach and islet further confirms that it plays a vital role in the regulation of physiological functions of the body. Besides, NUCB2 participates in tumorigenesis through activating various signal-pathways, more and more studies indicate that NUCB2 might impact tumor progression by promoting or inhibiting proliferation, apoptosis, autophagy, metastasis, and invasion of tumor cells. In this review, we comprehensively stated NUCB2's expression and functions, and introduced the role of NUCB2 in physiology and pathology and its mechanism. What is more, pointed out the potential direction of future research.

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.

Localization of Nucleobindin2/Nesfatin-1-Like Immunoreactivity in Human Lungs and Neutrophils

Nucleobindin2 (NUCB2)/nesfatin-1 expression in human plasma positively correlates with the expression of pro-inflammatory cytokines in patients with chronic obstructive pulmonary disease (COPD), implicating its potential role in neutrophilic lung inflammation. There are no data on the localization of nucleobindin2 (NUCB2)/nesfatin-1 in human lungs and inflammatory cells. We examined the localization of NUCB2/nesfatin-1-immunoreactivity in normal and inflamed human lungs obtained from COPD patients and neutrophils with light and immunoelectron microscopy. Immunohistology showed localization of NUCB2/nesfatin-1-like immunoreactivity in the bronchiolar epithelium, alveolar septa, vascular endothelium and various immune cells of normal and inflamed lungs. Further, NUCB2/nesfatin-1-like immunoreactivity accumulated within 0.5 μm of the plasma membrane in human neutrophils following 90 min. of 1 ng/mL LPS stimulation. NUCB2/nesfatin-1-like immunoreactivity was also found to localize in euchromatic portions of neutrophilic nuclei at five times the mean concentration compared to heterochromatin. Finally, our results indicate that NUCB2/nesfatin-1-like immunoreactivity is predominantly cytoplasmic including that in the Golgi complex and vesicles as it localizes at two times the concentration in neutrophilic cytoplasm compared to nucleus. Our study is the first to detail the localization of NUCB2/nesfatin-1-like immunoreactivity in lungs and neutrophils, and nuclear localization of NUCB2/nesfatin-1 also implicates its potential role in transcriptional regulation.

Loss of Nucleobindin-2/Nesfatin-1 increases lipopolysaccharide-induced murine acute lung inflammation

NUCB2/nesfatin-1 is expressed in variety of tissues. Treatment with nesfatin-1 reduces inflammation in rat models of subarachnoid hemorrhage-induced oxidative brain damage and traumatic brain injury as well as myocardial injury. There is only one study showing anti-inflammatory actions of nesfatin-1 on acute lung inflammation. To more precisely determine the role of NUCB2/nesfatin-1 in acute lung inflammation, we conducted a study using NUCB2/nesfatin-1 knockout (NKO) mice as well as neutrophils isolated from the bone marrows of WT and NKO mice. Our findings suggest that the absence of NUCB2/nesfatin-1 significantly increases the accumulation of adherent neutrophils by approximately 3 times compared with WT within LPS-treated lungs. Integrating this with observations from both BALF and neutrophil cytokine expression, we propose that although neutrophils lacking NUCB2/nesfatin-1 individually secrete less pro-inflammatory cytokines compared with stimulated WT cells, the result of knocking out NUCB2/nesfatin-1 is net pro-inflammatory. No change was found in NUCB2/nesfatin-1 mRNA or protein expression comparing WT LPS and PBS-treated samples. Taken together, our results show that NUCB2/nesfatin-1 is constitutively expressed in mouse lungs and neutrophils and demonstrates anti-inflammatory properties in mouse lungs during acute lung injury, by inhibiting adherent neutrophil accumulation and inflammatory cytokine expression.

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.

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.

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.

Immunostaining characteristics of irisin in benign and malignant renal cancers

We investigated the expression of irisin in renal cancers using immunocytochemistry. Irisin has been reported to exhibit anticancer properties. The study groups consisted of 22 cases each of control renal tissue, oncocytoma, chromophobe renal cell carcinoma (RCC), clear cell RCC (Fuhrman nuclear grades 1, 2, 3 and 4) and papillary RCC. We evaluated 10 slides for each of 176 cases. Slides were immunostained for irisin and histoscores were calculated for the prevalence and strength of immunostaining. Fuhrman nuclear grade 1, 2, 3 clear cell RCC and papillary RCC exhibited no irisin immunoreactivity. Irisin immunoreactivity was observed in some Fuhrman nuclear grade 4 RCCs. We found a significant decrease in irisin staining in chromophobe RCC compared to the control. Immunoreactivity in the oncocytoma tissue was comparable to the control group. Irisin immunoreactivity in chromophobe RCC decreased and no immunoreactivity was observed in Fuhrman nuclear grade 1, 2, 3 clear cell RCC and papillary RCC. Immunistochemical screening of irisin in renal oncocytomas and renal cancers may be useful for differential diagnosis.

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.