TGFB1 and arthritic joint disease: Deficiency of basal TGFβ signaling (non-priming) in Tgfbr2∆M mice resulted in significant suppression of peri-articular bone erosion, and reduction of osteoclast numbers and surface in resorption sites (Fig. 2i–k) of the tarsal joints in the K/BxN arthritis model in comparison to the WT control mice that mimic TGFβ priming condition.