Conventional Ly6Chi monocytes have developmental plasticity for a spectrum of differentiated phagocytes. Here we show, using conditional deletion strategies in a mouse model of Toll-like receptor (TLR) 7-induced inflammation, that the spectrum of developmental cell fates of Ly6Chi monocytes, and the resultant inflammation, is coordinately regulated by TLR and Notch signaling. Cell-intrinsic Notch2 and TLR7-Myd88 pathways independently and synergistically promote Ly6Clo patrolling monocyte development from Ly6Chi monocytes under inflammatory conditions, while impairment in either signaling axis impairs Ly6Clo monocyte development. At the same time, TLR7 stimulation in the absence of functional Notch2 signaling promotes resident tissue macrophage gene expression signatures in monocytes in the blood and ectopic differentiation of Ly6Chi monocytes into macrophages and dendritic cells, which infiltrate the spleen and major blood vessels and are accompanied by aberrant systemic inflammation. Thus, Notch2 is a master regulator of Ly6Chi monocyte cell fate and inflammation in response to TLR signaling.
All data generated or analysed during this study are included in the manuscript and supporting files.Data from RNA sequencing have been deposited to NCBI's Gene Expression Omnibus and are available under the accession number GSE147492.
Notch and TLR signaling coordinate monocyte cell fate and inflammationNCBI Gene Expression Omnibus, GSE147492.
- Jaba Gamrekelashvili
- Florian P Limbourg
- Jaba Gamrekelashvili
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Animal experimentation: All experiments were performed with 8-12 weeks old mice and age and sex matched littermate controls with approval of the local animal welfare board LAVES (Niedersächsisches Landesamt für Verbraucherschutz und Lebensmittelsicherheit), Lower Saxony, Animal Studies Committee, animal study proposals #14-1666, #16-2251, #18-2777, #2014-63, #2018-221). Mice were housed in the central animal facility of Hannover Medical School (ZTL) and were maintained and supervised as approved by the Institutional Animal Welfare Officer (Tierschutzbeauftragter).
- Florent Ginhoux, Agency for Science Technology and Research, Singapore
© 2020, Gamrekelashvili et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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