MAPK8 and diabetic kidney disease: Overexpression of OPN may lead to the activation and recruitment of macrophages, resulting in significant accumulation of macrophages and potentially affecting the inflammatory and fibrotic processes of DKD through the expression of transforming growth factor-β (TGF-β), extracellular signal-regulated protein kinases (ERK)/mitogen-activated protein kinase (MAPK), and Jun N-terminal kinase (JNK)/MAPK signaling pathways, causing renal damage46.