RAF1 and renal fibrosis: Inhibition of MCP-1/CCR2 axis can reduce the infiltration of macrophages into kidneys, thereby reducing inflammation and renal fibrosis in the damaged kidneys.[40] When MCP-1 binds to CCR2, a series of downstream signaling cascades, including janus kinase/signal transducer and activator of transcriptions, PI3K/mitogen-activated protein kinase, NF-κB, Ras/Raf-1/MEK/ERK and PI3K/Akt signaling pathways, can be activated (Fig. 1).[20,41] The activation of those pathways can modulate a variety of transcription factors and genes, and play critical roles in renal fibrosis.