Higher collagen deposition after infection in Cyb5r3 SPC–KO mice was accompanied by significantly higher transcript levels of Mmp12, Mmp13, Mmp14, and tissue inhibitor of metalloproteinases 1 (Timp1) (Figure 2F) but neither Timp2 nor Timp3 (Supplemental Figure 5A). Here, MMP12 is linked to infection.