As shown in Figure5, periodic acid–Schiff (PAS)‐staining, real‐time PCR, western blotting, and TUNEL labeling detected that overexpression of SARS‐CoV‐2 N in Smad3 WT mouse kidneys caused moderate to severe AKI at day 2 by a significant increase in tubular necrosis and serum levels of creatinine (Figure 5A,B). Here, SMAD3 is linked to acute kidney injury.