KLF5 and acute kidney injury: M1 polarization of infiltrating Mφ is additionally supported by parenchymal factors [e.g., Krüppel-like factor 5 (KLF5) expressed by collecting ducts (Fujiu et al., 2011) and suppressor of cytokine signaling 3 (SOCS3) upregulated by proximal tubules in AKI (Susnik et al., 2014)].