MMP14 and Leukoencephalopathy: Corroborating this, we also independently identified Mmp14 upregulation in Csf1r+/− mice, a model of leukoencephalopathy and microglial dyshomeostasis [172, 173], and confirmed its capacity to degrade PNNs via in vivo injection of recombinant MMP-14 (K.N.G., unpublished data).