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

• Published in: Genes 2022-09, Vol.13 (10), p.1680
• Main Authors: Wan, Yiping, Zhang, Zheng, Lin, Dongliang, Wang, Xinglong, Huang, Tianjiao, Su, Jiancheng, Zhang, Jiannan, Li, Juan, Wang, Yajun
• Format: Article
• Language: English
• Subjects: Adrenocorticotropic hormone; Adrenocorticotropic Hormone - genetics; Amino acid sequence; Amino acids; Amino Acids - genetics; Analysis; Animal models; Animals; Binding proteins; Biosynthesis; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cerebrum; Chickens; Chickens - genetics; Chickens - metabolism; Cloning; Cloning, Molecular; Corticotropin-releasing hormone; Corticotropin-Releasing Hormone - genetics; Corticotropin-Releasing Hormone - metabolism; DNA testing; DNA, Complementary; Feedback; Female; Gene expression; Genetic aspects; Glucocorticoids; Hypothalamic-pituitary-adrenal axis; Hypothalamo-Hypophyseal System - metabolism; Hypothalamus; Hypothalamus - metabolism; Mammals - genetics; Methods; Monoclonal antibodies; Neuropeptides; Ovaries; Pelodiscus sinensis; Peptides; Pituitary (anterior); Pituitary hormones; Pituitary-Adrenal System - metabolism; Poultry; RNA, Messenger - metabolism; Secretion; Stress response; Tissue Distribution; Vertebrates
• ISSN: 2073-4425; 2073-4425
• DOI: 10.3390/genes13101680

Corticotropin (ACTH) is a pituitary hormone playing important roles in stress response within the hypothalamus-pituitary-adrenal (HPA) axis. The biosynthesis and secretion of ACTH are controlled by multiple factors, including corticotropin-releasing hormone (CRH). As a key hypothalamus-derived regulator, CRH binds to corticotropin-releasing hormone receptor 1 (CRHR1) in the anterior pituitary gland to regulate ACTH synthesis and release. Thus, CRH-binding protein (CRHBP), which binds CRH with high affinity to inhibit CRH-induced ACTH secretion from pituitary cells, draws wide attention. In contrast to the extensive investigation of CRHBP in mammals and other lower vertebrates, the gene structure, tissue expression and physiological functions of CRHBP in birds remain largely unknown. In the present study, using chicken (c-) as our animal model, we examined the gene structure, tissue expression and functionality of CRHBP. Our results showed that: (1) cDNA encodes a 345 amino acid precursor, which shares high sequence identity with that of mammals, reptiles, frogs and fish; (2) is abundantly expressed in the brain (cerebrum and hypothalamus), pituitary and ovary; (3) cCRHBP inhibits the signaling of cCRHRs induced by cCRH, thus reducing the cCRH-induced ACTH secretion from cultured chick pituitary cells; (4) stress mediators (e.g., glucocorticoids) and stress significantly upregulate mRNA expression in chickens, supporting its role as a negative feedback regulator in the HPA axis. The present study enriches our understanding of the conserved roles of CRHBP across vertebrates. In addition, chicken is an important poultry animal with multiple economic traits which are tightly controlled by the HPA axis. The characterization of the chicken gene helps to reveal the molecular basis of the chicken HPA axis and is thus beneficial to the poultry industry.