Ovarian nesfatin-1 in Hemidactylus flaviviridis: Reproductive phase-dependent expression, role and hormonal regulation

Nesfatin-1 has recently emerged as a modulator of ovarian functions in mammals. Studies in non-mammalian vertebrates, though limited and majorly restricted to fishes, have evidenced a role of this peptide in the regulation of ovarian steroidogenesis and oocyte maturation. Interestingly, nesfatin-1 remains completely unexplored in reptiles. Therefore, the present study aimed to identify nesfatin-1 and elucidate its role and regulation in the ovary of Hemidactylus flaviviridis. Ovarian expression of nucb2/nesfatin-1 was highest during late recrudescence and breeding while it was lowest during regression. Follicular stage-dependent expression analysis showed significantly high expression of nucb2/nesfatin-1 in previtellogenic follicles. Further, in vitro treatment of recrudescent wall lizard ovaries with nesfatin-1 resulted in increased expression of anti-apoptotic gene, bcl-2, along with a concomitant decline in the pro-apoptotic gene, caspase-3. In addition, proliferation/differentiation markers like scf, c-kit, pcna, and bmp-15 were stimulated in ovaries incubated with the peptide. Ovarian steroidogenesis was also positively influenced by nesfatin-1 as treatment with the peptide resulted in heightened star expression as well as increased estradiol and progesterone production. Also, all concentrations of nesfatin-1 stimulated glucose uptake and metabolism in wall lizard ovary. Our observations provide the first evidence of ovarian functions of nesfatin-1 in a reptile. Further, ovarian nucb2/nesfatin-1 was differentially regulated by gonadotropin and sex steroids wherein its expression was stimulated by dihydrotestosterone (DHT) and 17β-estradiol (E2) but inhibited by follicle-stimulating hormone (FSH). In summary, this is the first report of the presence, reproductive stage-dependent expression, role, and regulation of ovarian nucb2/nesfatin-1 in H. flaviviridis.

Selenium protects against nesfatin-1 modulation of the hypothalamic-pituitary-testicular axis during hypothyroidism in male rats

Normal gonadal function can be disrupted by hypothyroidism. Hypothyroidism disturbs testicular function directly and centrally by affecting the hypothalamic-pituitary-testicular axis with unclear mechanism. As nesfatin-1 neurons co-localized with TRH and GnRH neurons in the hypothalamus, it could play a role in centrally hypothyroidism induced testicular dysfunction. Selenium (Se), by affecting thyroid iodide supply, could relieve these disturbances. So, we aim to identify the role of nesfatin-1 as a link between testicular dysfunction and hypothyroidism through modulating the MAPK/ERK pathway while discussing the possible role of Se in alleviating hypothyroidism and associated testicular damage. Forty male rats were divided equally into: Control: distilled water, Se: Se orally, Propylthiouracil (PTU): PTU orally, PTU + Se: Se with PTU orally. Serum thyroid function, gonadal hormones, nesfatin-1, testicular redox status, sperm analysis, brain tissue GnRH, nucleobindin 2-derived polypeptide, pMAPK/ERK gene expression, histological changes and immunohistochemical expression of testicular proliferating cell antigen (PCNA) were done. PTU induced hypothyroidism and reduction of gonadal hormones which both were correlated with reduced nesfatin-1. There was testicular stress with reduced GnRH, NUCB2, pMAPK/ERK gene expression, and PCNA immunopositive cells. These parameters were reversed by Se. Nesfatin-1 could be the central link between hypothyroidism and disturbances of the hypothalamic pituitary testicular axis.

Increased Serum Levels of Phoenixin-14, Nesfatin-1 and Dopamine Are Associated with Positive Pregnancy Rate after Ovarian Stimulation

BACKGROUND

We study the relationship between phoenixin (PNX-14), nesfatin-1 (NES-1), dopamine (DA) and oxytocin (OT) levels together with pregnancy rates in women after ovarian stimulation (OS).

METHODS

In a prospective case-control study, 56 infertile women were enrolled from the Department of Gynecological Endocrinology University Hospital. Infertile women age < 40 years old, with polycystic ovary syndrome (PCOS), confirmed tubal patency and suitable sperm quality were included. Blood samples were drawn twice-before the initiation of OS and before the human chorionic gonadotropin (hCG) administration. Assessments of PNX-14, NES-1, DA and OT serum levels were performed. Pregnancy rates after OS were observed.

RESULTS

Pregnant women showed higher baseline NES-1 and OT levels (+29.2% and +44%) but not PNX-14 and DA levels when compared to non-pregnant ones. In pregnant women, positive correlations between OT and prolactin, PRL (r = 0.47, p = 0.04), as well as between OT and NES-1 (r = 0.55, p = 0.02), were observed at baseline. At baseline, an OT level increase was associated with a positive pregnancy rate (per 100 pg/mL, OR = 1.39, 95% CI 1.04-1.74), while after OS, higher PNX-14 was a predictor of pregnancy (by 10 pg/mL, OR = 1.23, 95%CI 1.07-1.39). Post-stimulation PNX-14, NES-1 and DA concentrations were higher in pregnant women compared to non-pregnant ones (+17.4%, +26.1%, and +45.5%, respectively; all p < 0.05). In the pregnant group, OT levels were 2.7-times lower than in the remainder (p = 0.03). Moreover, in pregnant participants, a negative association between NES-1 and PNX (r = -0.53, p = 0.024) was observed.

CONCLUSION

Elevated PNX-14, NES-1 and DA along with decreased OT levels were observed in women who achieved pregnancy.

Plasma level of omentin-1, its expression, and its regulation by gonadotropin-releasing hormone and gonadotropins in porcine anterior pituitary cells

Omentin-1 (OMNT1) is an adipokine involved in the regulation of energy metabolism, insulin sensitivity, and reproduction. The present study was the first to investigate the plasma levels and expression of OMNT1 in the anterior pituitary (AP) gland on days 2-3, 10-12, 14-16, and 17-19 of the estrous cycle of normal-weight Large White (LW) and fat Meishan (MS) pigs. Next, we determined the effect of GnRH, LH, and FSH on the OMNT1 levels in cultured AP cells. The gene and protein expression of OMNT1 in AP fluctuated during the estrous cycle, with a higher expression in MS than in LW (except on days 10-12). However, plasma levels of OMNT1 were higher in LW than in MS. OMNT1 was localized in somatotrophs, lactotrophs, thyrotrophs, and gonadotrophs. In LW pituitary cells, GnRH and gonadotropins stimulated OMNT1 protein expression (except FSH on days 14-16) and had no effect on OMNT1 levels in the culture medium. In MS pituitary cells, we observed that GnRH and LH increased while FSH decreased OMNT1 protein expression. These findings showed OMNT1 expression and regulation in the porcine AP and suggested that OMNT1 could be a new player modifying the pituitary functions.

Estradiol and progesterone regulate NUCB2/nesfatin-1 expression and function in GH3 pituitary cells and THESC endometrial cells

Estradiol (E2) and progesterone (P4) are essential sex steroid hormones that play critical roles in the pituitary gland and uterus. Recently, nesfatin-1, a polypeptide hormone that regulates appetite and energy homeostasis in the hypothalamus, was found to be expressed in the pituitary gland and uterus. In this study, we aimed to investigate the relationship between these two steroid hormones and the expression and function of nesfatin-1 in the pituitary gland and uterus using GH3 cells, a lacto-somatotroph cell line, and THESC cells, an endometrial stromal cell line. First, we verified the presence of nesfatin-1 and nesfatin-1 binding sites in GH3 and THESC cells. E2 increased the mRNA expression of NUCB2, the gene encoding the nesfatin-1 protein, in GH3 cells, while P4 had no significant effect. In THESC cells, NUCB2 mRNA expression was decreased by E2 but increased by P4. In addition, nesfatin-1 significantly increased growth hormone (GH) and prolactin (PRL) mRNA expression in GH3 cells, and E2 enhanced this effect. In THESC cells, nesfatin-1 significantly increased the mRNA expression of insulin-like growth factor binding protein 1 (IGFBP1) and PRL, which are decidualization marker genes, and P4 further enhanced this effect. These results suggest that nesfatin-1 may act as a local regulator of GH and PRL production in the pituitary gland and decidualization in the uterus, modulating its effects in response to E2 and P4.

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

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

Serum nesfatin-1 level in men with diabetes and erectile dysfunction correlates with generalized anxiety disorder-7: A prospective comparative study

BACKGROUND

Current studies have suggested a close link between nesfatin-1, an appetite-related neuropeptide and gonadal hormones.

OBJECTIVES

We investigated the association between nesfatin-1 serum level and erectile dysfunction severity in men with diabetes as well as the generalized anxiety disorder-7 questionnaire, the patient health questionnaire-9, serum testosterone, kidney and liver functions, glycated haemoglobin and lipid profile.

MATERIALS AND METHODS

Seventy-five participants between 30 and 60 years were enrolled, 25 erectile dysfunction patients with type 2 diabetes (group I), 21 with diabetes and preserved erectile function (group II) and 29 healthy controls (group III). Erectile dysfunction status and severity were determined by the Arabic version of the international index of erectile function-5 for all the participants. Psychological wellbeing was checked by the generalized anxiety disorder-7 questionnaire and the patient health questionnaire-9. Finally, participants were evaluated for serum nesfatin-1, serum testosterone, kidney and liver functions, glycated haemoglobin and lipid profile.

RESULTS

Serum nesfatin-1 levels were significantly lower in groups I and II compared to the controls. The international index of erectile function-5 scores had shown significant correlations with serum nesfatin-1, serum testosterone, generalized anxiety disorder-7, patient health questionnaire-9, diastolic blood pressure, glycated haemoglobin, triglycerides, creatinine and albumin/creatinine ratio. Receiver operating characteristic analysis revealed that serum nesfatin-1 ≥ 0.62 ng/ml, serum testosterone ≥2.9 ng/ml, generalized anxiety disorder-7 score ≥7.5, patient health questionnaire-9 score ≥5, glycated hemoglobin ≥6.4%, triglycerides ≥ 144 mg/dl, creatinine ≥ 0.85 mg/dl and albumin/creatinine ratio ≥ 26.5 are useful predictors of erectile dysfunction in men with type 2 diabetes, and the area under the curve for those variables was respectively 0.83, 0.76, 1, 0.75, 0.88, 0.72, 0.67 and 0.77. Finally, a linear regression analysis revealed that generalized anxiety disorder-7 was the only strong independent predictor of the international index of erectile function-5 (p < 0.001).

DISCUSSION AND CONCLUSION

Nesfatin-1 can be used as a biomarker for the severity of anxiety in erectile dysfunction patients with diabetes. Use of this molecule in treatment of diabetes and erectile dysfunction should be strengthened by larger studies. Psychiatric care must be offered to patients with diabetes and erectile dysfunction and low serum nesfatin-1 as they experience intense anxiety and depression.

Nesfatin-1 as a potential marker for functional hypothalamic amenorrhea

OBJECTIVE

Nesfatin-1 plays an important role in regulating metabolism, appetite, gut motility, and eating behavior. It is suspected that abnormalities in nesfatin-1 secretion may be involved in the development of anorexia nervosa, and as such, this study aims to investigate the "circumstances of" nesfatin-1 in patients with functional hypothalamic amenorrhea (FHA).

MATERIALS AND METHODS

One hundred and forty-seven patients with FHA were enrolled to the present study. A control group consisting of 88 healthy, age-matched subjects was used. Both study and control groups had blood samples drawn to establish baseline serum concentrations of luteinizing hormone, follicle-stimulating hormone, estradiol, prolactin, thyroid-stimulating hormone, fT4, morning cortisol, dehydroepiandrosterone sulfate, testosterone, glucose, and insulin. Nesfatin-1 was also measured with the use of enzyme-linked immunosorbent assay.

RESULTS

Patients with FHA were found to have a significantly decreased concentration of serum nesfatin-1 when compared to healthy controls (6.21 ± 4.79 vs. 8.64 ± 6.63 respectively, p = 0.005). No statistically significant difference in nesfatin-1 levels was found between patients with normal and decreased BMI in the FHA group. Significant positive correlation was observed between serum nesfatin-1 concentration and 17-β-estradiol, while a significant negative correlation was observed between serum nesfatin-1 concentration and patient age, fasting glucose, and HDL levels.

CONCLUSIONS

This is the first known study to examine nesfatin-1 concentration in the context of clinical FHA. Patients with FHA were found to have decreased serum nesfatin-1 concentrations. This finding may prove instrumental in our future approach managing patients with FHA.

"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.

Epigenetic regulation of 5α reductase-1 underlies adaptive plasticity of reproductive function and pubertal timing

Background

Women facing increased energetic demands in childhood commonly have altered adult ovarian activity and shorter reproductive lifespan, possibly comprising a strategy to optimize reproductive success. Here, we sought to understand the mechanisms of early-life programming of reproductive function, by integrating analysis of reproductive tissues in an appropriate mouse model with methylation analysis of proxy tissue DNA in a well-characterized population of Bangladeshi migrants in the UK. Bangladeshi women whose childhood was in Bangladesh were found to have later pubertal onset and lower age-matched ovarian reserve than Bangladeshi women who grew-up in England. Subsequently, we aimed to explore the potential relevance to the altered reproductive phenotype of one of the genes that emerged from the screens.

Results

Of the genes associated with differential methylation in the Bangladeshi women whose childhood was in Bangladesh as compared to Bangladeshi women who grew up in the UK, 13 correlated with altered expression of the orthologous gene in the mouse model ovaries. These mice had delayed pubertal onset and a smaller ovarian reserve compared to controls. The most relevant of these genes for reproductive function appeared to be SRD5A1, which encodes the steroidogenic enzyme 5α reductase-1. SRD5A1 was more methylated at the same transcriptional enhancer in mice ovaries as in the women’s buccal DNA, and its expression was lower in the hypothalamus of the mice as well, suggesting a possible role in the central control of reproduction. The expression of Kiss1 and Gnrh was also lower in these mice compared to controls, and inhibition of 5α reductase-1 reduced Kiss1 and Gnrh mRNA levels and blocked GnRH release in GnRH neuronal cell cultures. Crucially, we show that inhibition of this enzyme in female mice in vivo delayed pubertal onset.

Conclusions

SRD5A1/5α reductase-1 responds epigenetically to the environment and its downregulation appears to alter the reproductive phenotype. These findings help to explain diversity in reproductive characteristics and how they are shaped by early-life environment and reveal novel pathways that might be targeted to mitigate health issues caused by life-history trade-offs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12915-021-01219-6.

The Role of the Gastric Hormones Ghrelin and Nesfatin-1 in Reproduction

Ghrelin and nesfatin-1 are enteroendocrine peptide hormones expressed in rat X/A-like and human P/D1cells of the gastric mucosa. Besides their effect on food intake, both peptides are also implicated in various other physiological systems. One of these is the reproductive system. This present review illustrates the distribution of ghrelin and nesfatin-1 along the hypothalamus–pituitary–gonadal (HPG) axis, their modulation by reproductive hormones, and effects on reproductive functions as well as highlighting gaps in current knowledge to foster further research.

The Role of the Gastric Hormones Ghrelin and Nesfatin-1 in Reproduction

Ghrelin and nesfatin-1 are enteroendocrine peptide hormones expressed in rat X/A-like and human P/D1cells of the gastric mucosa. Besides their effect on food intake, both peptides are also implicated in various other physiological systems. One of these is the reproductive system. This present review illustrates the distribution of ghrelin and nesfatin-1 along the hypothalamus-pituitary-gonadal (HPG) axis, their modulation by reproductive hormones, and effects on reproductive functions as well as highlighting gaps in current knowledge to foster further research.

The Role of the Gastric Hormones Ghrelin and Nesfatin-1 in Reproduction

Ghrelin and nesfatin-1 are enteroendocrine peptide hormones expressed in rat X/A-like and human P/D1cells of the gastric mucosa. Besides their effect on food intake, both peptides are also implicated in various other physiological systems. One of these is the reproductive system. This present review illustrates the distribution of ghrelin and nesfatin-1 along the hypothalamus–pituitary–gonadal (HPG) axis, their modulation by reproductive hormones, and effects on reproductive functions as well as highlighting gaps in current knowledge to foster further research.

GnRH pulse frequency and irregularity play a role in male aging

Gonadotropin-releasing hormone (GnRH) has a role in hypothalamic control of aging, but the underlying patterns and relationship with downstream reproductive hormones are still unclear. Here we report that hypothalamic GnRH pulse frequency and irregularity increase before GnRH pulse amplitude slowly decreases during aging. GnRH is inhibited by nuclear factor (NF)-κB, and GnRH pulses were controlled by oscillations in the transcriptional activity of NF-κB. Exposure to testosterone under pro-inflammatory conditions stimulated both NF-κB oscillations and GnRH pulses. While castration of middle-aged mice induced short-term anti-aging effects, preventing elevation of luteinizing hormone (LH) levels after castration led to long-term anti-aging effects and lifespan extension, indicating that high-frequency GnRH pulses and high-magnitude LH levels coordinately mediate aging. Reprogramming the endogenous GnRH pulses of middle-aged male mice via an optogenetic approach revealed that increasing GnRH pulses frequency causes LH excess and aging acceleration, while lowering the frequency of and stabilizing GnRH pulses can slow down aging. In conclusion, GnRH pulses are important for aging in male mice.

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.

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.

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.

Serum nesfatin-1 is associated with testosterone and the severity of erectile dysfunction

This cross-sectional study aimed to evaluate serum nesfatin-1 concentrations in patients with erectile dysfunction (ED). Patients with ED were selected from the Department of Urology of the Second Affiliated Hospital of Anhui Medical University. The International Index of Erectile Function-5 (IIEF-5) was used to evaluate the severity of ED. Serum nesfatin-1 and gonadal hormone levels, including luteinising hormone (LH), follicle-stimulating hormone (FSH) and testosterone were measured. The IIEF-5 scores (t = -21.034, p < .001) and nesfatin-1 levels (t = -7.043, p < .001) in patients with ED were significantly lower than in healthy controls. Moreover, patients with ED showed decreased testosterone levels (t = -3.478, p = .001), whereas there were no significant differences in serum levels of FSH (t = -0.088, p = .930) and LH (t = 1.114, p = .270) between the two groups. Furthermore, positive relationships were found between serum nesfatin-1 and testosterone concentrations (r = .742, p = .001) and IIEF-5 scores (r = .395, p = .009) in ED patients. Additionally, based on receiver operating characteristic curve analysis, the area under curve for nesfatin-1 was 0.884 with 83.3% sensitivity and 81.4% specificity in discriminating ED patients from healthy controls. The decrease in serum nesfatin-1 level may be related to testosterone and the severity of ED.

Phoenixin-20 Stimulates mRNAs Encoding Hypothalamo-Pituitary-Gonadal Hormones, is Pro-Vitellogenic, and Promotes Oocyte Maturation in Zebrafish

Phoenixin-20 (PNX-20) is a bioactive peptide with hormone-like actions in vertebrates. In mammals, PNX stimulates hypothalamo-pituitary-gonadal hormones and regulate reproductive processes. Our immunohisto/cytochemical studies show PNX-like and the putative PNX receptor, SREB3-like immunoreactivity in the gonads of zebrafish, and in zebrafish liver (ZFL) cells. Intraperitoneal injection of zebrafish PNX-20 upregulates mRNAs encoding both salmon gonadotropin-releasing hormone (GnRH), and chicken GnRH-II and kisspeptin and its receptor in zebrafish hypothalamus. Similarly, luteinizing hormone receptor mRNA expression in the testis, follicle-stimulating hormone receptor in the ovary, and the kisspeptin system were upregulated in the gonads of PNX-20 injected fish. We also observed the upregulation of genes involved in the sex steroidogenic pathway (cyp11a1, cyp17a1, 17βhsd, cyp19a1a) in the gonads of PNX-20 administered fish. PNX-20 upregulates the expression of vitellogenin isoforms and estrogen receptor (esr2a and 2b) mRNAs in ZFL cells in vitro. Meanwhile, siRNA-mediated knockdown of PNX-20 resulted in the downregulation of all vitellogenin transcripts, further suggesting its possible role in vitellogenesis. PNX-20 treatment resulted in a significant increase in germinal vesicle breakdown in zebrafish follicles in vitro. Collectively, these results provide strong evidence for PNX-20 effects on the HPG axis and liver to promote reproduction in zebrafish.

Does nesfatin-1 influence the hypothalamic–pituitary–gonadal axis in adult males with obstructive sleep apnoea?

There is growing evidence that obstructive sleep apnoea (OSA) influences the hypothalamic–pituitary–gonadal axis (HPG axis) in men. The aim of the study was to assess the association of nesfatin-1 with HPG axis disturbances in OSA. This is a prospective study with consecutive enrolment. It comprises 72 newly diagnosed OSA patients ((AHI: apnoea-hypopnea index) 18 subjects: 5 ≤ AHI < 15; 24: 15 ≤ AHI < 30; 30: AHI ≥ 30) and a control group composed of 19 patients (AHI < 5). All patients underwent polysomnography and fasting blood collection for nesfatin-1, testosterone, luteinising hormone (LH), high-sensitivity C-reactive protein (hsCRP), aspartate transaminase (AST), alanine aminotransferase (ALT), creatinine and glucose. Groups had similar levels of LH, nesfatin-1 and testosterone (p = 0.87; p = 0.24; p = 0.08). Nesfatin-1 was not correlated to LH (p = 0.71), testosterone (p = 0.38), AHI (p = 0.34) or the oxygen desaturation index (ODI) (p = 0.69) either in the whole group, or in sub-groups. The study did not reveal any association between the HPG axis and nesfatin-1 in OSA adult males. It is possible that nesfatin-1 is not a mediator of HPG axis disturbances in adult patients with OSA.

Increasing hypothalamic nucleobindin 2 levels and decreasing hypothalamic inflammation in obese male mice via diet and exercise alleviate obesity-associated hypogonadism

To explore the role of nesfatin-1 in regulating male reproductive function during energy balance variation, we employed an obese mouse model which was first induced by a high-fat diet (HFD) and followed by interventions of a normal diet (ND) and/or moderate exercise, and then serum reproductive hormones of male mice, hypothalamic nucleobindin 2 (NUCB2)/nesfatin-1, inflammatory factors, and gonadotropin-releasing hormone (GnRH) levels were tested. Our findings showed that both serum nesfatin-1, follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) levels and hypothalamic NUCB2/nesfatin-1 and Gnrh mRNA levels were reduced, whereas, the mRNA and protein levels of hypothalamic tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, inhibitor kappa B kinase β (IKKβ), and nuclear factor (NF)-κB were increased in obese male mice. Diet, exercise, and diet combined with exercise interventions reversed the decreases in serum nesfatin-1, FSH, LH, and T levels; increased hypothalamic NUCB2/nesfatin-1 and Gnrh mRNA levels; and reduced hypothalamic TNF-α, IL-1β, IKKβ, and NF-κB levels. These changes were accompanied by reduced adiposity, and these effects were more obvious in the diet combined with exercise group. Overall, our findings suggested that the hypogonadotropic hypogonadism associated with obesity may be induced by reduced hypothalamic NUCB2/nesfatin-1 levels, which attenuated the stimulatory effect on GnRH directly or indirectly by suppressing its anti-inflammatory effect in the brain. Diet and/or exercise interventions were able to alleviate the hypogonadotropic hypogonadism associated with obesity, potentially by increasing hypothalamic NUCB2/nesfatin-1 levels.

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

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

Centrally administered kisspeptin suppresses feeding via nesfatin-1 and oxytocin in male rats

Kisspeptin (KP), known as a hypothalamic neuropeptide, plays a critical role in the regulation of not only reproduction but also food intake. The anorectic neuropeptides, nesfatin-1 and oxytocin (OXT), are expressed in central nervous system, particulaly in various hypothalamic nuclei, and peripheral tissue. We examined the effects of the intracerebroventricular (icv) administration of KP-10 on feeding and nesfatin-1-immunoreactive (ir) or OXT-ir neurons in the rat hypothalamus, using Fos double immunohistochemistry in male rats. Cumulative food intake was remarkably decreased 0.5-3 h after icv administration of KP-10 (6.0 μg) compared to the vehicle treated and the KP-10 (3.8 μg) treated group. The icv administration of KP-10 significantly increased the number of nesfatin-1-ir neurons expressing Fos in the supraoptic nucleus (SON), paraventricular nucleus (PVN), arcuate nucleus (ARC), dorsal raphe nucleus, locus coeruleus, and nucleus tractus solitarius. The decreased food intake induced by KP-10 was significantly attenuated by pretreatment with the icv administration of antisense RNA against nucleobindin-2. After icv administration of KP-10, the percentages of OXT-ir neurons expressing FOS were remarkably higher in the SON and PVN than for vehicle treatment. The KP-10-induced anorexia was partially abolished by pretreatment with OXT receptor antagonist (OXTR-A). The percentage of nesfatin-1-ir neurons expressing Fos-ir in the ARC was also decreased by OXTR-A pretreatment. These results indicate that central administration of KP-10 activates nesfatin-1- and OXT neurons, and may play an important role in the suppression of feeding in male rats.

Phoenixin: Expression at different ovarian development stages and effects on genes ralated to reproduction in spotted scat, Scatophagus argus

Phoenixin (Pnx), a recently discovered neuropeptide, has been implicated in reproduction. Pnx mainly exists in two active isoforms, phoenixin-14 (Pnx-14) and phoenixin-20 (Pnx-20). However, little is known about the functions of Pnx in teleosts. To determine the roles of Pnx in the regulation of reproduction in Scatophagus argus, the physiological characterization of the Pnx was analyzed. During ovary development, the expression of pnx in phase IV was higher than in phase II and III in the hypothalamus. In the pituitary, pnx expression was highest in phase IV, moderate in phase III, and lowest in phase II. When hypothalamus and pituitary fragments were cultured in vitro with Pnx-14 and Pnx-20 (10 nM and 100 nM) for 6 h, the expression of GnRHR (gonadotropin releasing hormone receptor), lh (luteinizing hormone) and fsh (follicular stimulating hormone) in the pituitary increased significantly, except GnRH (gonadotropin releasing hormone) in the hypothalamus. Similarly, the expression of GnRHR, lh and fsh in the pituitary increased significantly after injecting S. argus with Pnx-14 and Pnx-20 (10 ng/g and 100 ng/g body weight (bw)), except GnRHR and fsh treated with 10 ng/gbw Pnx-20 in the pituitary and GnRHs in the hypothalamus. These results indicate that Pnx may not only stimulate the reproduction of the S. argus through the hypothalamic-pituitary-gonadal (HPG) axis, but also directly through the pituitary.

Current Understanding of the Role of Nesfatin-1

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

Nesfatin-1 Regulates Feeding, Glucosensing and Lipid Metabolism in Rainbow Trout

Nesfatin-1 is an 82 amino acid peptide that has been involved in a wide variety of physiological functions in both mammals and fish. This study aimed to elucidate the role of nesfatin-1 on rainbow trout food intake, and its putative effects on glucose and fatty acid sensing systems. Intracerebroventricular administration of 25 ng/g nesfatin-1 resulted in a significant inhibition of appetite, likely mediated by the activation of central POMC and CART. Nesfatin-1 stimulated the glucosensing machinery (changes in sglt1, g6pase, gsase, and gnat3 mRNA expression) in the hindbrain and hypothalamus. Central fatty acid sensing mechanisms were unaltered by nesfatin-1, but this peptide altered the expression of mRNAs encoding factors regulating lipid metabolism (fat/cd36, acly, mcd, fas, lpl, pparα, and pparγ), suggesting that nesfatin-1 promotes lipid accumulation in neurons. In the liver, intracerebroventricular nesfatin-1 treatment resulted in decreased capacity for glucose use and lipogenesis, and increased the potential of fatty acid oxidation. Altogether, the present results demonstrate that nesfatin-1 is involved in the homeostatic regulation of food intake and metabolism in fish.