In an ischemia/reperfusion-induced animal AKI model, the renoprotective effect of vitamin D occurred via peroxisome proliferator-activated receptor gamma (PPAR-γ) [46], and pretreatment with paricalcitol also had a renoprotective effect, possibly via Toll-like receptor 4 (TLR4)/NF-κB-mediated inflammation [47]. The gene discussed is TLR4; the disease is acute kidney injury.