Early precursor-derived pituitary gland tissue-resident macrophages play a pivotal role in modulating hormonal balance [bulk RNA-Seq]

Macrophages were identified in the pituitary gland long ago, but until recently, we lacked the resolution to comprehensively profile the pituitary gland macrophage compartment. To address this, we examined the developmental kinetics and distinctive characteristics of pituitary macrophages within the developing and homeostatic gland. Whole pituitary glands were collected from newborn (NB) to adult (8 weeks old) wild-type (WT) mice. Our analysis revealed diverse macrophage subsets with marked differences in gene expression profiles and spatial localization, undergoing dynamic phenotypic changes from neonatal stages to adulthood. We observed distinct transcriptional profiles between macrophage subpopulations in the anterior and posterior lobes, underscoring significant molecular divergences. Fate-mapping analyses showed that pituitary macrophages originate from early yolk sac precursors and persist throughout life primarily through local proliferation, even under pathophysiological conditions. Overall design: To investigate the transcriptome changes in the pituitary gland after macrophage depletion. Macrophages were ablated with function-blocking aCSF1R antibody. The first injection was given during embryo development at E6.5. After birth, an aCSF1R antibody was given every second week (4 times in total), and tissues were collected one week after the last injection (at the age of 5 weeks).