Publication

PPARγ is essential for the development of bone marrow erythroblastic island macrophages and splenic red pulp macrophages

Journal Paper/Review - Jan 3, 2021

Units
PubMed
Doi

Citation
Okreglicka K, Schneider C, Nielsen P, Ludewig B, Kurrer M, Feng Q, Onder L, Pohlmeier L, Iten I, Kopf M. PPARγ is essential for the development of bone marrow erythroblastic island macrophages and splenic red pulp macrophages. J Exp Med 2021; 218
Type
Journal Paper/Review (English)
Journal
J Exp Med 2021; 218
Publication Date
Jan 3, 2021
Issn Electronic
1540-9538
Brief description/objective

Tissue-resident macrophages play a crucial role in maintaining homeostasis. Macrophage progenitors migrate to tissues perinatally, where environmental cues shape their identity and unique functions. Here, we show that the absence of PPARγ affects neonatal development and VCAM-1 expression of splenic iron-recycling red pulp macrophages (RPMs) and bone marrow erythroblastic island macrophages (EIMs). Transcriptome analysis of the few remaining Pparg-deficient RPM-like and EIM-like cells suggests that PPARγ is required for RPM and EIM identity, cell cycling, migration, and localization, but not function in mature RPMs. Notably, Spi-C, another transcription factor implicated in RPM development, was not essential for neonatal expansion of RPMs, even though the transcriptome of Spic-deficient RPMs was strongly affected and indicated a loss of identity. Similarities shared by Pparg- and Spic-deficient RPM-like cells allowed us to identify pathways that rely on both factors. PPARγ and Spi-C collaborate in inducing transcriptional changes, including VCAM-1 and integrin αD expression, which could be required for progenitor retention in the tissue, allowing access to niche-related signals that finalize differentiation.