J LI 1,2, S HOLLAND 3, H ROBERTSON 1, A MALLETT 3,4, S ALEXANDER 5, P O’CONNELL 1,2, N ROGERS 1,2,6
1Westmead Institute For Medical Research, Westmead, Australia, 2Westmead Clinical School, Faculty of Health and Medicine, University of Sydney, Westmead, Australia, 3Institute for Molecular Bioscience, Brisbane, Australia, 4College of Medicine and Dentistry, James Cook University, Townsville, Australia, 5Children’s Medical Research Institute, Westmead, Australia, 6Department of Renal Medicine, Westmead Hospital, Westmead, Australia
Aim: To determine if adoptively transferred tolerogenic dendritic cells (TolDC) can protect against acute kidney injury (AKI).
Background: Tolerogenic dendritic cells (TolDC) are under investigation in transplantation and autoimmunity, but their therapeutic utility in AKI is unexplored
Methods: Bone marrow dendritic cells (BMDC) and TolDC were generated ex-vivo from C57BL6 or Balb/C mice in culture for 7 days ± lipopolysaccharide (LPS) stimulation. Live, CD11c-enriched cells were adoptively transferred (1x106cells/mice) into 12-week-old male, C56BL6 mice concurrent with bilateral renal IRI (20 minutes/35.6-36°c). Mice from control (PBS) or cell therapy groups [syngeneic LPS-treated TolDC (LPS-TolDC) or allogeneic-TolDC (AlloTolDC)] were analysed 24-hours post-reperfusion for renal function, histology and biomolecular phenotyping. Additional mice were subjected to bilateral IRI (22minutes/36.5°c) to assess the impact of liposomal clodronate on cell therapy.
Results: LPS-TolDC and AlloTolDC, but not TolDC, provided protection against AKI, with serum creatinine 42.7±29umol/L (p=0.006), 40.1±30.3umol/L (p=0.001) and 97.3±33.5umol/L (p=0.28) respectively compared to 122.4±44.7umol/L in controls. Cell death was reduced in LPS-TolDC and AlloTolDC compared to controls (2.3, 4.9 vs 25.9 TUNEL+ve/hpf, p=0.02). mRNA analysis revealed reduced pro-inflammatory cytokine and antioxidant expression (IL-6/TNF-alpha/CCL2/superoxide dismutase/inducible-NOS, p<0.05).
Flow analysis of the kidney showed LPS-TolDC localise to the kidney (7.7 vs 3.5 % CD45+, p <0.001 compared to TolDC) but there was no significant difference in absolute CD45+, or proportions of T-, neutrophils or myeloid cells between LPS-TolDC and controls. Despite differences in subsets based on CD11b, CD11c, F4/80 and Ly6C, depletion of recipient myeloid cells with liposomal clodronate did not impair the reno-protective capacity of AlloTolDC (creatinine 30.6±19umol vs 155±44.7umol/L, p<0.001).
Conclusion: TolDCs demonstrate potent protective effects against renal ischemia reperfusion injury and is not dependent on recipient myeloid cells
Jen is a nephrologist and a PhD candidate at the Westmead Institute for Medical Research under the supervision of A/Prof Natasha Rogers, Prof Stephen Alexander and Prof Philip O’Connell. Her research focuses on the the importance of innate immunity on acute kidney injury and transplantation.
Her other interest areas include amyloidosis and monoclonal gammopathies of renal significance