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Kidney Week

Abstract: FR-PO1111

Blockade of PKCδ in Donor Kidneys Protects Against Cold Ischemia-Reperfusion Injury in Kidney Transplantation

Session Information

  • Transplantation: Basic
    November 08, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Transplantation

  • 1901 Transplantation: Basic

Authors

  • Zhu, Jiefu, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
  • Dong, Zheng, Medical College of Georgia at Augusta University, Augusta, Georgia, United States
Background

Ischemia-reperfusion injury (IRI) is an inevitable consequence of kidney transplantation. PKCδ has been reported to contribute to mitochondrial pathway of apoptosis during cell stress, but role of PKCδ in kidney IRI remains unknown. This study aims to evaluate the role and regulation of PKCδ in cold storage with renal transplantation.

Methods

C57BL/6 mice kidneys were preserved in an ice bath for 0.5, 4, 8, 10 or 14 hours in University of Wisconsin solution (UWS) and transplanted into syngeneic recipients. Renal injury and regeneration were examined at 24 hours or day 6 after transplantation. The responses of kidneys from wild-type and PKCδ-null mice were examined and compared. Rat proximal tubular cells (RPTC) were exposed to hypothermia at 4°C with UWS incubation and then changed with complete medium in 37°C. Mitochondria morphology was examined under confocal microscopy and mitochondria dysfunction was evaluated by Cytochrome C release and Bax translocation. Active and kinase-dead PKCδ were transfected to determine the role of PKCδ in RPTC cells.

Results

Post-transplant injury in WT kidneys was mild when cold storage time was shorter than 4 hours, but the injury increased notably with 8 hours and longer cold storage. Ki-67+ tubules peaked at 8 hours of cold storage, while longer cold storage suppressed post-transplant tubular proliferation. PKCδ was activated during cold storage as indicated by its phosphorylation at Y-311 and proteolysis. WT kidneys with 10 hours cold preservation showed remarkable damage and tubular apoptosis at 24 hours after transplantation. In comparison, PKCδ-KO kidneys had significant less injury and better tubular proliferation. Furthermore, PKCδ-KO kidneys had improved kidney repair and function as life-supporting kidney at day 6 when native kidneys were removed from recipient. Consistently, pharmacological inhibitors of PKCδ also prevented early post-transplant injury at day 1. In RPTC cells, mitochondrial fragmentation and leakage were involved in cold storage injury. Mitochondrial injury and cell death were inhibited by PKCδ kinase-dead mutant but were aggravated by active PKCδ fragment.

Conclusion

PKCδ is activated during cold storage of donor kidneys and mediates subsequent renal IRI during kidney transplantation. Inhibition of PKCδ may alleviate kidney injury during cold storage and benefit subsequent renal transplantation.

Funding

  • NIDDK Support