MMP9 and stroke disorder: One study shows that, via stabilizing MKP-1, IRAK-M can suppress p38 activation (Su et al., 2007), while p38 activation can lead to MMP-9 increase in astrocytes (Gorina et al., 2011), composing a possibility that p38 activation in IRAK-M-null mice upregulates MMP-9 in the experimental stroke.