Progranulin protects against endotoxin-induced acute kidney injury by downregulating renal cell death and inflammatory responses in mice

Progranulin (PGRN), a pluripotent secreted growth factor, is involved in various physiologic and disease processes. However, the role of PGRN in endotoxin-induced septic acute kidney injury (AKI) remains unknown. The objective of this study is to investigate the protective effects of PGRN on an endotoxin-induced AKI mouse model by using PGRN-deficient mice and recombinant PGRN (rPGRN) pretreatment. PGRN levels were increased in kidneys of wild-type (WT) mice at 6 and 24 h after lipopolysaccharide (LPS) injection. Renal function detection, hematoxylin and eosin staining, immunohistochemical staining, ELISA and in situ terminal deoxynucleotidyl transferase-mediated uridine triphosphate nick-end labeling were used to reveal tissue injury, inflammatory cell infiltration, production of inflammatory mediators and cell death in mouse kidneys after LPS injection. PGRN deficiency resulted in severe kidney injury and increased apoptotic death, inflammatory cell infiltration, production of pro-inflammatory mediators and the expression and nucleus-to-cytoplasmic translocation of HMGB1 in the kidney. In addition, rPGRN administration before LPS treatment ameliorated the endotoxin-induced AKI in WT mice. PGRN may be a novel biologic agent with therapeutic potential for endotoxin-induced septic AKI possibly by inhibiting LPS-induced renal cell death and inflammatory responses in mice.