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Kidney Week

Abstract: SU-OR05

Pannexin 1 Channel Regulates Mitochondrial Function and Cell Survival During AKI

Session Information

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Poudel, Nabin, Division of Nephrology and Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia, Charlottesville, Virginia, United States
  • Schinderle, Colleen, Division of Nephrology and Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia, Charlottesville, Virginia, United States
  • Skrypnyk, Nataliya, Division of Nephrology and Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia, Charlottesville, Virginia, United States
  • Medina, Christopher B., Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States
  • Rosin, Diane L., Division of Nephrology and Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia, Charlottesville, Virginia, United States
  • Ravichandran, Kodi S., Department of Microbiology, Immunology, and Cancer Biology, University of Virginia, Charlottesville, Virginia, United States
  • Okusa, Mark D., Division of Nephrology and Center for Immunity, Inflammation, and Regenerative Medicine, University of Virginia, Charlottesville, Virginia, United States

Group or Team Name

  • Center for Immunity, Inflammation and Regenerative Medicine (CIIR), University of Virginia
Background

Pannexin 1 (Panx1) is a membrane associated non-selective channel that, when activated, serves as a conduit for release of small metabolites that have pro- or anti-inflammatory function. We have previously shown that pharmacological inhibition or genetic deletion of Panx1 in mice prior to injury is protective against renal ischemia-reperfusion injury (IRI). How Panx1 contributes to acute kidney injury (AKI) pathology is unknown. We hypothesized that Panx1 induces cell death by mediating both intracellular and extracellular events.

Methods

We subjected a novel human Panx1 overexpressing mouse (hPANX1-Tg) to IRI or cisplatin-mediated AKI and assessed plasma creatinine and renal expression of neutrophil gelatin associated lipocalin (Ngal). For in vitro studies, PANX1 overexpressing TKPTS cells (OX) were challenged with cisplatin. Cell death was assessed by flow cytometry using Annexin-V/7AAD. Mitochondrial function was assessed by measuring oxygen consumption rate, mitochondrial membrane potential and ROS production. mRNA expression was measured using real-time PCR.

Results

hPANX1-Tg mice had significant rise in plasma creatinine and expression of Ngal in the kidneys in both models of AKI compared to their littermate controls. Cisplatin-induced cell death was greater in OX cells compared to control cells. Moreover, cisplatin induced greater death in OX cells than control cells when cultured together. Among genes involved in the cell death pathway, OX cells had reduced expression of Bcl2 and a greater increase in Ho-1 after cisplatin exposure. Assessment of mitochondria showed that OX cells had reduced mitochondrial DNA, Pgc1a expression, and mitochondrial respiration at baseline, a greater reduction in mitochondrial function and a higher increase in mitochondrial ROS production after cisplatin exposure compared to controls.

Conclusion

Our data demonstrate that PANX1 overexpression results in overt renal injury during AKI that is in part mediated by reduced mitochondrial function and in part by metabolites released via Panx1 channels, which facilitates cell death. These results complement our prior studies demonstrating that Panx1 deficiency protects kidneys from IRI and provide strong rationale for the development of selective strategies to inhibit Panx1 in the prevention or treatment of AKI.

Funding

  • NIDDK Support