To assess the functional changes of Tregs during experimental periodontitis, in terms of their capacity to control bone-loss by directly inhibiting the differentiation of osteoclasts, we co-cultured Tregs from healthy (bTregs) and diseased (pTregs) mice (10 days after periodontitis induction) with BMM in the presence of RANKL and M-CSF (Fig. 5A). The gene discussed is TNFSF11; the disease is periodontitis.