Abstract: PO0171
Kidney Proximal Tubular NFκB Essential Modulator Exacerbates Ischemic AKI
Session Information
- AKI Mechanisms - 1
October 22, 2020 | Location: On-Demand
Abstract Time: 10:00 AM - 12:00 PM
Category: Acute Kidney Injury
- 103 AKI: Mechanisms
Authors
- Han, Sang Jun, College of Physicians and Surgeons of Columbia University, New York, New York, United States
- Kim, Mihwa, College of Physicians and Surgeons of Columbia University, New York, New York, United States
- D'Agati, Vivette D., College of Physicians and Surgeons of Columbia University, New York, New York, United States
- Lee, H. Thomas, College of Physicians and Surgeons of Columbia University, New York, New York, United States
Background
Ischemic acute kidney injury (AKI) is a major clinical problem. We previously showed that renal tubular peptidylarginine deiminase 4 exacerbates ischemic AKI by promoting pro-inflammatory NFκB activation pathway via selective citrullination of NFκB Essential MOdulator (NEMO). Since NEMO plays important and diverse physiological roles in almost all cell types, here, we tested whether renal proximal tubular (PT) NEMO plays a critical role in ischemic AKI utilizing mice lacking PT NEMO and by targeted PT NEMO inhibition with mesoscale nanoparticle encapsulated NEMO binding peptide (NBP MNP) delivery.
Methods
We subjected PT NEMO deficient mice, wild type (WT) mice and C57BL/6 mice to 30 min renal ischemia and 24 hours reperfusion (RIR). C57BL/6 mice received NBP MNP before RIR injury to test whether selective PT NEMO inhibition attenuates ischemic AKI. Separate cohorts of PT NEMO deficient mice or WT mice were injected with recombinant PAD4 (rPAD4) before 20 min renal ischemia to test whether PAD4-mediated exacerbation of ischemic AKI is PT NEMO dependent. In addition, isolated PT from PT NEMO deficient mice and WT mice were treated with rPAD4 or human PT cells were treated rPAD4 after pretreatment of NBP MNP to determine whether PAD4 activates renal proximal tubular pro-inflammatory signaling via NEMO activation.
Results
PT NEMO deficient mice and C57BL/6 mice treated with NBP MNP were protected against ischemic AKI with decreased plasma creatinine (1±0.2, 1.7±0.2 mg/dL), NGAL mRNA (153.6±31.8, 433.2±54.7 fold increase over sham, N=5-7), renal tubular necrosis, inflammation and apoptosis compared to WT or control MNP treated mice (Cr=2.1±0.03, 2.7±0.2 mg/dL, NGAL=752.8±176.3, 840.8±74.7 fold increase over sham, N=5-7). Exogenous rPAD4 exacerbated RIR injury in WT mice but not in PT NEMO deficient mice. Furthermore, rPAD4 upregulated pro-inflammatory cytokine and NFκB activation in freshly isolated PT cells from WT mice but not from PT NEMO deficient mice. Treatment of NBP MNP also protected rPAD4-mediated pro-inflammatory cytokine induction in cultured human PT cells.
Conclusion
Taken together, our studies suggest that renal PT NEMO plays a critical role in ischemic AKI by promoting renal tubular inflammation, apoptosis as well as necrosis. Our studies provide novel insight to the pathophysiology of PT NEMO in ischemic AKI, suggesting a potential therapy for ischemic AKI.
Funding
- NIDDK Support