Figure 6.

Tracking of the migration and homing of circulatory osteoclast progenitors (OCPs) to the affected sites in B6 mice with collagen-induced arthritis (CIA). (A) Experimental timeline for CIA model and intravascular (IV) staining in B6 mice. Increased recirculation of OCPs (CD45⁺CD3^–B220^-NK1.1^-Ly6G^-CD11b⁺CD115⁺) from arthritic mice (CIA) in comparison to control (ctrl). Hematopoietic blood cells were stained in vivo by intravenous (i.v.) anti-CD45 fluorescent (PE) antibody. Mice were sacrificed and harvested periarticular bone marrow (PBM) was stained ex vivo by anti-CD45 fluorescent (APC) antibody. Double-positive cells represent the intravascular compartment (PE⁺APC⁺ IV), whereas single-positive cells represent the resident compartment (PE^–APC⁺ RES) within PBM. Representative dot plots and cell frequencies for ctrl and CIA are shown. (B) Experimental timeline for CIA model and adoptive transfer in B6 mice. Adoptive transfer of sorted tdTomato-positive spleen (SPL) OCPs (CD45⁺CD3^-B220^-NK1.1^-Ly6G^-CD11b⁺CD115⁺) from LysMcre/Ai9 mice to the host B6 mice with arthritis was performed (total 0.5×10⁶ cells/mouse i.v.). Representative dot plots of sorting efficiency for tdTomato⁺ graft OCPs are shown on the left. Frequencies of host (tdTomato^-) and graft (tdTomato⁺) OCPs (CD45⁺CD115⁺CCR2⁺) in SPL and PBM are presented on the right. LY—CD3/B220/NK1.1.