MAPK1 and diabetic kidney disease: By immunostaining of tissue sections, we found that MAPK1 was upregulated while PACS-2 was downregulated in the renal tubules of patients with DKD compared with that in healthy controls (Figure 4A-C). Correlation analysis showed that increased MAPK1 was negatively correlated with eGFR, whereas the levels of PACS-2 were positively correlated with eGFR (Figure S6A-B), suggesting that the upregulation of MAPK1 and down-regulate of PACS-2 may contribute to the impairment of renal function in patients with DKD.