垂體（pituitary）是下丘腦-垂體-腎上腺 （HPA） 軸的重要樞紐。垂體激素分泌細胞 （HPC） 釋放多種激素，以在正常和壓力條件下調節基本身體功能。垂體內分泌腺通過釋放促腎上腺皮質激素 （ACTH） 來調節免疫系統，以響應下丘腦的神經元激活。然而，目前尚不清楚全身炎癥如何調節垂體HPC的轉錄組學特征。在這里，我們對小鼠垂體進行了單細胞RNA測序（scRNA-seq），發現在炎癥發生時，所有主要的垂體HPC都以細胞類型特異性方式產生強烈反應，其中皮質促物表現出強烈的反應。全身炎癥還導致非典型生物活性分子的產生和釋放，包括皮質激素的 Nptx2，以調節免疫穩態。同時，HPCs上調了趨化因子的基因表達，促進了HPCs與免疫細胞之間的通訊。總之，我們的研究揭示了垂體和免疫系統之間的廣泛相互作用，表明垂體在介導炎癥對身體生理學許多方面的影響方面發揮著多方面的作用。

Macrophage depletion and virus injection in the pituitary

Mice were anesthetized with pentobarbital (80 mg/kg, i.p.) before surgery and then placed in a mouse stereotaxic instrument. Injections were performed using a microsyringe pump and a Micro4 controller (World Precision Instruments). For macrophage depletion, liposome-PBS or liposome-Clodronate (Liposoma,CP-005-005) was stereotaxically microinjected into the anterior pituitary (2.5 mm posterior from Bregma, 0.4 mm lateral, 6 mm below pia). The liposomes were delivered to the target site at a rate of 60 nL/min for 500 nL per site. Mice received saline or 0.5 mg/kg LPS 18 h after liposome delivery and were killed 6 h after inflammation was established. For CCL2 expression and Nptx2-KO, AAV was delivered directly into the pituitary. The injection site, rate, and volume were the same as those used for the liposome injection. Subsequent experiments were performed at least 3 weeks after virus injection.

(C) Representative images showing Iba1 (the marker of macrophage) expression in the pituitary from mice that received liposome-PBS (left) or liposome-Clodronate (right) directly to the pituitary for 24 h. Scale bar, 100 μm.

(D) Serum concentrations of ACTH in saline- or LPS-treated (0.5 mg/kg LPS for 6 h) mice pretreated with liposome-PBS or liposome-Clodronate (n = 4–7 mice).

(E) Serum concentrations of corticosterone in LPS-treated (0.5 mg/kg LPS for 6 h) mice pretreated with liposome-PBS or liposome-Clodronate (n = 6–7 mice).