Evidence for Neuropeptide W Acting as a Physiological Corticotropin-releasing Inhibitory Factor in Male Chickens

Abstract

In vertebrates, corticotropin (ACTH), released by the pituitary gland, is a critical part of the stress axis and stress response. Generally, the biosynthesis and secretion of ACTH are controlled by both hypothalamic stimulatory factors and inhibitory factors (e.g., CRIF), but the identity of this CRIF remains unrevealed. We characterized the neuropeptide B (NPB)/neuropeptide W (NPW) system in chickens and found that NPW could directly target the pituitary to inhibit growth hormone and prolactin secretion via neuropeptide B/W receptor 2 (NPBWR2), which is completely different from the mechanism in mammals. Present study first carried out a series of assays to investigate the possibility that NPW acts as a physiological CRIF in chickens. The results showed that: (1) NPW could inhibit ACTH synthesis and secretion by inhibiting the cAMP/PKA signaling cascade in vitro and in vivo; (2) NPBWR2 was expressed abundantly in corticotrophs (ACTH-producing cells), which are located mainly in cephalic lobe of chicken pituitary, as demonstrated by single-cell RNA-sequencing, immunofluorescent staining and fluorescence in situ hybridization; (3) dexamethasone could stimulate pituitary NPBWR2 and hypothalamic NPW expression in chicks, which was accompanied by the decease of POMC mRNA levels, as revealed by in vitro and subcutaneous injection assays; and (4) the temporal expression profiles of NPW-NPBWR2 pair in hypothalamus-pituitary axis and POMC in pituitary were almost unanimous in chicken. Collectively, these findings provide comprehensive evidence for the first time that NPW is a potent physiological CRIF in chickens that plays core roles in suppressing the activity of the stress axis.

A Gene Expression Atlas of Lohmann White Chickens

“…It is widely assumed that hypothalamic GHRH activates GHRH receptor (GHRHR) to stimulate GH synthesis and release in the pituitary of chickens (Wang et al, 2007). Interestingly, NPBWR2 has recently been previously implicated in pituitary gland function as a novel inhibitory secretagogue for GH, prolactin, and ACTH in chickens (Bu et al, 2016; Liu et al, 2022). In this study, DRD2 was demonstrated to mediate the effect of dopamine to inhibit VIP-induced cPRL expression in the chicken anterior pituitary (Lv et al, 2018).…”

“…The publication of the chicken genome (Red junglefowl) in 2004 paved the way for understanding the genetic basis for distinguishing the different phenotypes of domesticated chickens from their wild relatives (K. 1, 2004). Recent studies using population resequencing data and de novo assembled-based chicken pan-genome have improved the sequencing quality for the assembly of complete avian genomes and revealed that the numbers of chicken genes are comparable to those of other tetrapod vertebrates and a new pan-genome pattern of birds (Li et al, 2022;Wang et al, 2021). In addition to pan-genome analyses, transcriptome annotation is crucial for a wide array of biological research areas (Cunningham et al, 2022).…”

Characterization of the chicken melanocortin 5 receptor and its potential role in regulating hepatic glucolipid metabolism

“…The ACTH in the plasma was about 10 pg/ml (∼2.2 pmol/l) in 4–6 days chicks determined by a two-site sequential chemiluminescent immunometric assay ( Gaston et al, 2017 ). The concentration of plasma ACTH was about 12 pg/ml in hatched chicks ( Okur et al, 2022 ) and 7–18 pg/ml in three-week-old male chicks from our recent study ( Liu et al, 2022 ). There is little information on the circulating concentrations of chicken α-MSH, which is also known to be present in systemic circulation for regulating pigmentation ( Ling et al, 2003 ) or lipolytic activity ( Shipp et al, 2017 ) in different chicken tissues.…”

Characterization of CRH-Binding Protein (CRHBP) in Chickens: Molecular Cloning, Tissue Distribution and Investigation of Its Role as a Negative Feedback Regulator within the Hypothalamus–Pituitary–Adrenal Axis

“…For the in vivo studies, according to our earlier study [ 10 ], DEX was administered subcutaneously, and the hypothalamus and pituitary were collected for RNA extraction to determine the CRHBP mRNA expression using qPCR. In the experiment, three-week-old male chicks were reared at 22 °C with a 16L:8D (16 h light, 8 h dark) photoperiod and were fed with commercial diet regularly and water freely.…”

“…For example, neurons in the paraventricular nucleus (PVN) of the hypothalamus synthesize and secrete corticotropin-releasing hormone (CRH), which binds corticotropin-releasing hormone receptor 1 (CRHR1), expressed in the anterior pituitary corticotroph to regulate the ACTH synthesis and release [ 7 , 8 , 9 ]. The neuropeptide W (NPW), recently identified in chickens, which binds to the neuropeptide B/W receptor 2 (NPBWR2), inhibits ACTH synthesis and release [ 10 ].…”