Submitted January 7, 2008
Accepted August 4, 2008
Bone marrow microenvironment controls the in vivo differentiation of murine dendritic cells into osteoclasts
Abdelilah Wakkach, Anna Mansour, Romain Dacquin, Emmanuel Coste, Pierre Jurdic, Georges F. Carle, and Claudine Blin-Wakkach*
GEPITOS, UMR6235, CNRS/Universite de Nice Sophia-Antipolis, Nice, France
LBMC, UMR 5161, ENS, CNRS, Lyon, France
* Corresponding author; email: blin{at}unice.fr.
Finding that activated T cells control osteoclast (OCL) differentiation has revealed the importance of the interactions between immune and bone cells. Dendritic cells (DCs) are responsible for T cell activation and share common precursors with OCLs. Here, we show that DCs participate in bone resorption more directly than simply through T cell activation. We show that among the splenic DC subsets, the conventional DCs (cDCs) have the higher osteoclastogenic potential in vitro. We demonstrate that cDCs differentiate into functional OCLs in vivo when injected into osteopetrotic oc/oc mice defective in OCL resorptive function. Moreover, this differentiation involves the presence of activated CD4+ T cells controlling a high RANK-L expression by bone marrow stromal cells. Our results open new insights in the differentiation of OCLs and DCs and offer new basis for analyzing the relations between bone and immune systems.
