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Kidney Week

Abstract: TH-PO095

Endothelial Cells Regulate Post-Ischemic Kidney Repair Through PHD/HIF-Dependent Hyperglycolysis

Session Information

  • AKI: Mechanisms - I
    November 02, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Tiwari, Ratnakar, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • An, Si Young, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Sharma, Rajni, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Borkowski, Gabriella, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • O'Sullivan, James, Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Quaggin, Susan E., Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
  • Kapitsinou, Pinelopi P., Northwestern University Feinberg School of Medicine, Chicago, Illinois, United States
Background

Recently, we showed that inhibiting the oxygen-sensing molecule prolyl hydroxylases (PHDs) controls human endothelial cell (EC) metabolism and angiogenic ability. However, in the context of acute kidney injury (AKI), little is known about the functions of endothelial PHDs. Here, we used a genetic approach in conjunction with scRNA-seq to investigate the roles of endothelial PHDs in post-ischemic kidney repair.

Methods

To delete PHD1, PHD2, and PHD3 in ECs, VECadherin (Cdh5)-CreER transgenic mice were crossed to mice carrying conditional PHD1, PHD2, and PHD3 alleles, generating PHD TiEC mice. For our loss of function studies, we generated mice that lack the constitutive HIF-1β (ARNT) in ECs (ARNT iEC). Ischemia-reperfusion injury (IRI) was induced by uni-/bilateral renal artery clamping, and tamoxifen treatment was started at day 1 post IRI, followed by analysis at day 14.

Results

Compared to Cre- controls, day 14 post IRI kidneys of PHD TiEC showed significant upregulation of profibrotic genes Loxl2, Tgfβ1, and Acta2, increased collagen deposition (n=6-8, p≤0.05), higher tubular injury, and reduced capillary density. Further, PHD TiEC showed a 26% reduction in glomerular filtration rate than Cre- controls (n=7, p≤0.01). Suppression of post-ischemic EC-HIF signaling in ARNT iEC mice ameliorated kidney injury and fibrosis assessed by similar analyses as indicated above (n=6-7, P≤0.5). scRNA-seq analysis of the day 14 post-IRI kidney revealed a hyperglycolysis signature in the medullary EC of PHD TiEC mice compared to Cre- mice. Among the significantly upregulated glycolytic genes was Slc16a3, a HIF target gene that encodes the lactate transporter MCT4, known to mediate lactate efflux. Notably, post-ischemic administration of the dual MCT4/MCT1 inhibitor Syrosingopine (Syro) attenuated kidney injury in PHD TiEC mice (n=4, P≤0.5). In vitro, Syro or MCT4 siRNA suppressed the hypoxia/reoxygenation+IL1-β (1ng/ml) induction of EC-adhesion molecules VCAM1 and ICAM1, leading to reduced monocyte adhesion to human EC (n=3, P≤0.5).

Conclusion

In summary, endothelial PHDs regulate post-ischemic kidney repair through HIF-dependent mechanisms. Furthermore, our studies identify the endothelial MCT4 as a potential target for renoprotective therapies.

Funding

  • NIDDK Support