Biology subjects

Gamrekelashvili, J.

Publications and source records attributed to Gamrekelashvili, J..

2 recordsLinked to original sources

bioRxiv2024

Canonical Notch2 Signaling Regulates the Development of Iron-recycling Macrophages and Iron Homeostasis

Red pulp macrophages (RPM) and bone marrow macrophages (BMM) are iron-recycling cells involved in iron homeostasis and erythropoiesis. Here, we show, using conditional deletion strategies of Notch signaling components, that the development of RPM and BMM is regulated by canonical Notch2 signaling. Loss of functional Notch2, or its nuclear mediator Rbpj, causes impairment in RPM and BMM and iron overload in the spleen and bone marrow, while prototypic RPM genes required for iron handling are downregulated. This was accompanied by splenic extramedullary hematopoiesis and changes in splenic microarchitecture. Furthermore, early postnatal transfer of bone marrow and fetal liver progenitors rescued the defects in RPM and BMM and iron overload in a Notch2-dependent manner, demonstrating the potential to restore defective tissue resident macrophage niches by Notch-competent progenitors. Thus, canonical Notch2 is required for development and function of iron-recycling macrophages.

immunology↗

bioRxiv2020

Notch and TLR signaling coordinate monocyte cell fate and inflammation

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 and ectopic differentiation of Ly6Chi monocytes into macrophages and dendritic cells, which appear in the blood stream and infiltrate the spleen and major blood vessels, resulting in unrestrained systemic inflammation. Thus, Notch2 is a master regulator of Ly6Chi monocyte cell fate and inflammation in response to TLR signaling.

immunology↗