MMP3 and Arthritis: Treating the 5-mo-old DNase II−/−STINGS365A/S365A mice with anti–IL-6R reduced the arthritis score (Fig. 7 D) and the expression of IL-6 and MMP-3 but did not reduce the expression of TNF-α, CXCL1, and CXCL2 (Fig. 7 E).