Crosstalk between prolactin, insulin-like growth factors, and thyroid hormones in feather growth regulation in neonatal chick wings

Yuri Nozawa; Ayako Okamura; Hibiki Fukuchi; Masamichi Shinohara; Sayaka Aizawa; Sakae Takeuchi

doi:10.1016/j.ygcen.2024.114657

Crosstalk between prolactin, insulin-like growth factors, and thyroid hormones in feather growth regulation in neonatal chick wings

Gen Comp Endocrinol. 2024 Dec 17:361:114657. doi: 10.1016/j.ygcen.2024.114657. Online ahead of print.

Authors

Yuri Nozawa¹, Ayako Okamura², Hibiki Fukuchi¹, Masamichi Shinohara¹, Sayaka Aizawa³, Sakae Takeuchi⁴

Affiliations

¹ Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, 3-1-1 Kitaku, Tsushimanaka, Okayama 700-8530, Japan.
² Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Kitaku, Tsushimanaka, Okayama 700-8530, Japan.
³ Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, 3-1-1 Kitaku, Tsushimanaka, Okayama 700-8530, Japan; Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Kitaku, Tsushimanaka, Okayama 700-8530, Japan.
⁴ Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, 3-1-1 Kitaku, Tsushimanaka, Okayama 700-8530, Japan; Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Kitaku, Tsushimanaka, Okayama 700-8530, Japan. Electronic address: stakeuch@cc.okayama-u.ac.jp.

PMID: 39701429
DOI: 10.1016/j.ygcen.2024.114657

Abstract

The elongation of primary feathers in neonatal chicks is delayed by the late-feathering K gene located on the Z chromosome. We recently found that the K gene slows feather growth by reducing the number of functional prolactin (PRL) receptor (PRLR) dimers. In this study, we investigated the molecular mechanisms by which PRL promotes feather elongation. RT-qPCR and immunohistochemistry analyses revealed that PRLRs are predominantly localized in the pulp rather than in the epidermal layer of the feather follicle. Treatment of primary cultured feather pulp cells with PRL increased the expression of mRNAs for insulin-like growth factors (IGFs; IGF-1 and IGF-2) and type 2 deiodinase (DIO2). Furthermore, treatments with IGF-1 and triiodothyronine (T3) reciprocally enhanced the expression of mRNAs for DIO2 and IGFs. Additionally, BrdU staining in neonatal chicks showed that T3 promoted cell proliferation in both the epidermal layer and pulp cells, while this effect was suppressed by an IGF-1 receptor (IGF1R) inhibitor. These findings suggest a novel model in which PRL upregulates IGFs and DIO2 in feather pulp cells, creating a positive feedback loop between IGFs and T3, ultimately leading to the promotion of cell proliferation in both the epidermal layer and the pulp cells by IGFs. This is the first report proposing crosstalk between PRL, thyroid hormone (TH), and IGFs in feather follicles.

Keywords: Feather growth; IGF; Iodothyronine deiodinase; Prolactin; Thyroid hormone.