Novel Regulatory Factors in the Hypothalamic-Pituitary-Ovarian Axis of Hens at Four Developmental Stages

Abstract

Ovarian follicular development is an extremely complex and precise process in which the hypothalamic-pituitary-ovarian (HPO) axis plays a crucial role. However, research on the regulatory factors of the HPO axis is sparse. In this study, transcriptomes of the tissues in the entire HPO axis at 15, 20, 30, and 68 w of age were analyzed. In total, 381, 622, and 1090 differentially expressed genes (DEGs) were found among the hypothalamus, pituitary, and ovary, respectively. In particular, the greatest number of DEGs (867) was identified from the comparison of ovary at 30 and 15 w, which might be related to ovarian development and function at high ovulation capacity. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that most of these DEGs in the significantly enriched biological process (BP) terms and pathways were primarily involved in tissue development and the regulation of reproductive hormone biosynthesis and secretion. The latter is highly related to the HPO axis. Therefore, a number of hub candidate genes strongly associated with the HPO axis in each tissue were filtered by analyzing the Protein-protein interaction (PPI) network and seven known reproductive hormone-associated key genes were obtained: PGR, HSD3B2, CYP17A1, CYP11A1, CYP21A2, STS , and CYP19A1 , and 12 novel genes: ROCK2, TBP, GTF2H2, GTF2B, DHCR24, DHCR7, FDFT1, LSS, SQLE, MSMO1, CYP51A1 , and PANK3 . These will be utilized for further research into the function of the HPO axis. This study has highlighted the major role of the HPO axis in the reproduction of hens at the four developmental stages and explored the novel factors that might regulate reproduction, thus providing new insights into the function of the HPO axis on the reproductive system.

Adiponectin modulates steroid hormone secretion, granulosa cell proliferation and apoptosis via binding its receptors during hens’ high laying period

“…However, unlike mammals, poultry have a unique reproduction system with numbers of various sizes of follicles in the ovary to maintain continuous ovulation during the high laying period. A hen's follicle consists of oocytes surrounded by granulosa and theca layers that store theca cells and granulosa cells individually and produce different steroid hormones that mainly participate in the regulation of follicular growth, maturation, and atresia ( Johnson, 2015 ; Li et al., 2020 ). Thus, to investigate the effect of adiponectin on steroid synthesis and secretion in hens’ ovaries, we detected the levels of E2 and P4 in the granulosa cells via adding 5 µg/mL or 10 µg/mL AdipoRon and found that the activation of adiponectin could significantly enhance the secretion of P4 and suppress E2 in granulosa cells to further affect ovarian function, which was consistent with the findings in bat and geese ( Singh and Krishna, 2012 ; Bo et al., 2019 ).…”

“…The total protein in granulosa cells was collected using the Whole Cell Extraction Kit (Solarbio, Beijing, China) after washing with a PBS solution, and the protein concentration was analyzed using Pierce Rapid Gold BCA Protein Assay kit (Elabscience; Wuhan, China). Then the protein samples were centrifuged at 12,000 r/min for 5 min, extracted the supernatant and the following process adhered to the method of a previous study ( Li, 2020 ), which was also strictly in accordance with the manufacturer's recommendations. The primary and secondary antibodies of goat AdipoR1/2, rabbit GAPDH and HRP-goat/rabbit anti rabbit/goat were purchased from Abcam and Google, respectively.…”

Transcriptomic Analysis of Laying Hens Revealed the Role of Aging-Related Genes during Forced Molting

“…AGO4 is closely related to ovarian development in laying hens, and its mutation may induce ovarian cancer [82]. Inhibition of ROCK2 expression can promote autophagy in cardiomyocytes under the induction of starvation and senescence, thus slowing aging [83], and ROCK2 in chickens can regulate ovarian follicular development through the hypothalamic-pituitary-ovarian axis [84]. RFX7 can maintain the basic function of natural killer cells and improve immune defense mechanisms in animals [85].…”

Research Progress on the Effect of Epilepsy and Antiseizure Medications on PCOS Through HPO Axis

“…The hypothalamus pulse generator regulates the pulse release of gonadotropin-releasing hormone (GnRH) neurons, which act on the pituitary gland and regulate the secretion of LH and FSH. The latter acts on the ovaries to stimulate follicular growth and produce estradiol so as to effectively coordinate the function of the HPO axis (26)(27)(28)(29). The hormones released by the pituitary and ovary can also negatively regulate the secretion of hormones in the hypothalamus-pituitary system and maintain the homeostasis of the reproductive endocrine system.…”