@article{b0cc4d06004d4bdcb3b65f25974a83c4,
title = "Monocytes-macrophages that express α-smooth muscle actin preserve primitive hematopoietic cells in the bone marrow",
abstract = "Hematopoietic stem and progenitor cells (HSPCs) are regulated by various bone marrow stromal cell types. Here we identified rare activated bone marrow monocytes and macrophages with high expression of α-smooth muscle actin (α-SMA) and the cyclooxygenase COX-2 that were adjacent to primitive HSPCs. These myeloid cells resisted radiation-induced cell death and further upregulated COX-2 expression under stress conditions. COX-2-derived prostaglandin E 2 (PGE 2) prevented HSPC exhaustion by limiting the production of reactive oxygen species (ROS) via inhibition of the kinase Akt and higher stromal-cell expression of the chemokine CXCL12, which is essential for stem-cell quiescence. Our study identifies a previously unknown subset of α-SMA + activated monocytes and macrophages that maintain HSPCs and protect them from exhaustion during alarm situations.",
author = "Aya Ludin and Tomer Itkin and Shiri Gur-Cohen and Alexander Mildner and Elias Shezen and Karin Golan and Orit Kollet and Alexander Kalinkovich and Ziv Porat and Gabriele D'Uva and Amir Schajnovitz and Elena Voronov and Brenner, {David A.} and Apte, {Ron N.} and Steffen Jung and Tsvee Lapidot",
note = "Israeli Science Foundation [ISF 544/09]; European Commission [CELL-PID FP7-261387]; Leona M. and Harry B. Helmsley Charitable TrustWe thank G.N. Enikolopov (Cold Spring Harbor Laboratory) for nestin-G FP mice; Y. Yarden (Weizmann Institute of Science) for the 3T3 cell line; N. Iscove for guidance during the study and for critical review of the manuscript; H. Perlman for help in the characterization of myeloid cells; J. Hanna for use of the FACSAria; and D. Shafritz, J. Canaani, K. Lapid and Y. Ovadia for critical review of the manuscript. Supported by the Israeli Science Foundation (ISF 544/09), the European Commission (CELL-PID FP7-261387) and the Leona M. and Harry B. Helmsley Charitable Trust.",
year = "2012",
month = nov,
day = "1",
doi = "10.1038/ni.2408",
language = "الإنجليزيّة",
volume = "13",
pages = "1072--1082",
journal = "Nature Immunology",
issn = "1529-2908",
publisher = "Nature Research",
number = "11",
}