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Kidney Week

Abstract: FR-OR026

CD4 T Cell-Derived Neutrophil Gelatinase-Associated Lipocalin (NGAL) Mediates Ischemia Reperfusion-Induced AKI

Session Information

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Lee, Sul A, Johns Hopkins University , Baltimore, Maryland, United States
  • Noel, Sanjeev, Johns Hopkins University , Baltimore, Maryland, United States
  • Kurzhagen, Johanna T., Johns Hopkins University , Baltimore, Maryland, United States
  • Sadasivam, Mohanraj, Johns Hopkins University , Baltimore, Maryland, United States
  • Pierorazio, Phillip M., Brady Urological Institute, Johns Hopkins University, Baltimore, Maryland, United States
  • Arend, Lois J., Johns Hopkins Hospital, Baltimore, Maryland, United States
  • Hamad, Abdel, Johns Hopkins University , Baltimore, Maryland, United States
  • Rabb, Hamid, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
Background

T cells mediate tissue injury and repair processes following ischemia reperfusion (IR) and nephrotoxin induced acute kidney injury (AKI). While exploring underlying mechanisms involved in T cell mediated AKI/repair, we unexpectedly identified lipocalin 2 (Lcn2) as the most upregulated gene in post IR kidney CD4 T cells. Functional studies of Lcn2 encoded neutrophil gelatinase-associated lipocalin (NGAL), a biomarker for early detection of AKI, showed important role in T cell mediate AKI pathophysiology.

Methods

WT mice were subjected to IR and kidney CD4 T cells flow sorted after 24 hours. An unbiased RNA sequencing was carried out to determine transcriptional effects of IRI on kidney CD4 T cell response. Flow cytometry and ELISA was performed to validate RNA-seq data. Adoptive transfer studies were performed using NGAL KO, CD 4 KO and WT mice. Pre and post clamp human kidney samples from RCC nephrectomies were also evaluated.

Results

RNA-seq analysis showed Lcn2 mRNA as the top upregulated (60-fold) gene in CD4 T cells from post IR mouse kidney. RT-PCR validated RNA-seq data and showed increased Lcn2 expression (P< 0.05) in post IR renal CD4 T cells. ELISA showed increased NGAL protein in renal CD4 T cells (244±24 vs 8±5 ng/mg; p < 0.001) and spleen CD4 T cells (261±44 vs. 42±19 ng/mg; p < 0.01) post IR compared to controls. Adoptive transfer of splenic CD4 T cells from NGAL KO mice significantly increased serum creatinine (SCr) than CD4 T cell from WT mice or the PBS in CD4 KO recipients (1.80±0.26; 1.06±0.21 and 0.97±0.25 mg/dL respectively; p=0.04) and in the WT recipients (1.47±0.17; 0.93±0.17 and 0.73±0.17 mg/dL respectively; p=0.02). In vitro simulated hypoxia increased Lcn2 (1.7-fold) and Ifn-γ (8.8- fold) mRNA expression in CD4 T cells from NGAL KO mice compared to CD4 T cells from WT mice. NGAL increased significantly (38.8±3.9 % vs.15.4±5.9 %, P < 0.05) in post clamp human kidney T cells compared to pre clamp.

Conclusion

These data show that kidney CD4+ cell Lcn2/NGAL responds rapidly to IRI, directly mediates kidney structural and functional responses to ischemic AKI, and modifies CD4 cell Ifn-γ. NGAL, traditionally thought to be a candidate biomarker for AKI, is an important molecular regulator of the CD4+ T cell response during ischemic AKI

Funding

  • NIDDK Support