Kidney-targeting ANXA2 nanoparticles alleviate renal ischemia-reperfusion injury by inhibiting necroptosis via CHMP2A.

Renal ischemia-reperfusion injury (IRI) is a severe complication after kidney surgery or transplantation, often leading to acute kidney injury and chronic kidney disease. Current preventive strategies are limited, leaving a critical gap in patient care. Annexin A2 (ANXA2) is known to be upregulated post-IRI, but its precise functional role in mitigating injury and its therapeutic potential have remained largely unexplored. This study investigates ANXA2's protective mechanisms, specifically focusing on its interaction with membrane repair pathways.

Researchers used ANXA2 knockout (KO) and wild-type mice subjected to a renal IRI model to assess injury, fibrosis, and cell death. In vitro, mouse renal tubular epithelial cells (TECs) were used with ANXA2 or CHMP2A knockdown/overexpression. Molecular mechanisms were elucidated via co-immunoprecipitation, mass spectrometry, and immunofluorescence. A novel Kidney-Targeting Peptide (KTP)-conjugated, ANXA2-loaded lipid nanoparticle (KTP-LNP@ANXA2) was synthesized and characterized for stability and biocompatibility. Its efficacy was then tested in vitro and as a pre-treatment in the mouse renal IRI model.

ANXA2 was significantly upregulated post-IRI, predominantly in the renal medulla. ANXA2 KO mice exhibited exacerbated medullary injury, increased fibrosis, and enhanced necroptosis, evidenced by elevated phosphorylated MLKL (p-MLKL) levels and severe apical membrane disruption. No genotype-dependent differences were observed in apoptosis, pyroptosis, or ferroptosis markers at 24 h. ANXA2 deficiency also amplified the inflammatory response, increasing neutrophil infiltration through the upregulation of C-X-C motif chemokine ligand (CXCL) 1 and CXCL2.

Mechanistically, ANXA2 associated with CHMP2A, a component of the ESCRT-III membrane repair complex, following IRI, promoting ESCRT-III assembly at the apical membrane to counteract necroptosis.

Knocking down CHMP2A abolished ANXA2's protective effect. The engineered KTP-LNP@ANXA2 demonstrated excellent stability, biocompatibility, and enhanced uptake by renal TECs. Pre-treatment with KTP-LNP@ANXA2 in mice effectively delivered ANXA2 to the kidneys, attenuated IRI severity, and reduced necroptosis.