FBS Colloquia No.226Laboratory of Immunology and Cell Biology

Identification of arthritis-associated osteoclast precursors in the synovium

Osteoclasts have a unique bone-destroying capacity, playing key roles in steady-state bone remodeling and arthritic bone erosion. Whether these osteoclasts in the different tissue settings arise from the same precursor states of monocytoid cells is presently unknown. Here, we show that osteoclasts in pannus originate exclusively from circulating bone marrow-derived cells and not from locally-resident macrophages. We identify a specific macrophages subset in the inflamed synovium with high potential to form osteoclasts. Single cell RNA-seq analysis of the population further identified that a small subset of cells transitioning from osteoclast precursors to pathogenic osteoclasts in situ and further analysis of the population may lead to identify a potential target for treatment of rheumatoid arthritis.