Objective: To investigate the role and mechanisms of Rictor in antibody-mediated rejection (ABMR) of renal allografts.
Methods: Mouse acute ABMR model was established with inducible macrophage ablation of Rictor. Changes of kidney grafts injury, polarization markers of macrophages, NF-κB pathway and NRLP3 inflammasome associated proteins in ABMR mice were detected by histological staining, immunohistochemistry, flow cytometry, immunofluorescence staining, qRT-PCR and Western blot. Macrophages infiltrated in kidney grafts were sorted by magnetic beads for RNA-seq to explore the downstream molecular mechanisms of Rictor in regulating macrophage activation.
Result: We found that macrophage infiltration and M1 macrophage polarization were significantly up-regulated both in kidney tissues from patients and animal models with ABMR. We then generated a mouse acute ABMR model with inducible macrophage ablation of Rictor. The knockouts promoted M1 macrophage polarization and exacerbated pathological injury in kidney grafts compared to controls. Rictor deficiency in primary BMDMs promoted M1 macrophage polarization and activated the NF-κB pathway to promote NRLP3 inflammasome activation. Mechanistically, Rictor may inhibit macrophage activation to ameliorate the progression of ABMR of renal allografts by targeting p65 ubiquitination and NLRP3 transcription.
Conclusion: Mouse acute ABMR model was successfully constructed and characterized. Rictor inhibits macrophage activation to ameliorate the progression of ABMR of renal allografts by targeting p65 ubiquitination and NLRP3 transcription, which may provide new insights into the Rictor/mTORC2 pathway as a therapeutic target in ABMR.