Abstract: FR-PO164

Transfer of Exogenous Mitochondria Protects the Kidneys from Ischemia-Reperfusion Injury

Session Information

  • Mitochondriacs and More
    November 03, 2017 | Location: Hall H, Morial Convention Center
    Abstract Time: 10:00 AM - 10:00 AM

Category: Acute Kidney Injury

  • 001 AKI: Basic

Authors

  • Bajwa, Amandeep, University of Virginia, Charlottesville, Virginia, United States
  • Schlegel, Kailo H., University of Virginia, Charlottesville, Virginia, United States
  • Alexander, Kyle J., University of Virginia, Charlottesville, Virginia, United States
  • Kurmaeva, Elvira, University of Virginia, Charlottesville, Virginia, United States
Background

Mitochondria, a critical player in acute kidney injury, have dual roles as primary source of energy (ATP) and as key regulators of cell death. Ischemia induces altered bioenergetics with increased mitochondrial swelling and reactive oxygen species and ultimately cell death. Ischemia followed by reperfusion (IRI) induces mitochondrial fragmentation in 30-40% of proximal tubule (PT) cells. Therapeutic interventions that target to improve mitochondrial health to repair, reprogram or replace mitochondria to restore respiratory functions are beneficial for prevention and/or treatment of disease.

Methods

Renal injury was assessed by plasma creatinine (PCr; mg/dl). 8-wk old C57BL/6 [WT or Rag1ko] mice were i.v. injected with exogenous mitochondria (Exo-Mito; 0-500mcg protein equivalent) 1d prior to 26 mins IRI. Exo-Mito was isolated from healthy non-ischemic mouse liver. Splnx was done 7d prior to IRI. Structure (sonicated) or function (Rot/Ant A) of Exo-Mito altered prior to injection. For in vitro studies, PT cells (TKPTS) were treated with 200 mcg of Exo-Mito 1d prior to analysis that included measurement of ATP levels, mitochondrial functions (Seahorse flux analyzer), cytokines (pcr), immunofluorescence microscopy (uptake efficiency) and flow cytometry (dyes [mitotracker or JC-1]).

Results

In vivo studies demonstrated mitochondria (200mcg, mouse or human) treated mice are significantly protected compared to vehicle treated mice after IRI [PCr (2.2±0.05 vs 0.62±0.2), p<0.01]. The protection by transferred Exo-Mito in IRI studies was partially abrogated in absence of a spleen but maintained in Rag1ko mice. Furthermore, structurally or functionally altered Exo-Mito no longer protected kidneys from IRI. Transfer of labeled Exo-Mito signal was found in spleen (in macrophages), kidney (in PT, identified with anti-CD13 antibody [labels brush border]), liver and lungs. In vitro studies demonstrate that Exo-Mitochondria are taken up by TKPTS in a dose dependent manner. TKPTS with Exo-Mito had significantly higher levels of extra- and intracellular ATP, higher basal oxygen consumption rate and spare respiratory capacity measured by Seahorse analyzer and lower cytokines after LPS stimulation.

Conclusion

Our current study demonstrates that up take of Exo-Mito by PT cells (in vivo and in vitro) helps maintain bioenergetics [ATP] to prevent injury.

Funding

  • NIDDK Support