Moreover, Tan et al. demonstrated that MMP9 can also cleave the ECM protein osteopontin (OPN) to enhance macrophage recruitment in a mouse model of renal fibrosis.34 Despite this, additional studies are required to understand how MMP-mediated degradation of other ECM components alters immune cell recruitment and fibrotic disease development. The gene discussed is SPP1; the disease is renal fibrosis.