Abstract: FR-PO373

Nuclear Localization of Phosphatase and Tensin Homolog (PTEN) Causes Cell Cycle Arrest and Is Associated with Kidney Fibrosis

Session Information

Category: Chronic Kidney Disease (Non-Dialysis)

  • 308 CKD: Mechanisms of Tubulointerstitial Fibrosis

Authors

  • Ajay, Amrendra Kumar, Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Akinfolarin, Akinwande A., Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Bonventre, Joseph V., Brigham and Women's Hospital, Boston, Massachusetts, United States
  • Sabbisetti, Venkata, Brigham and Women's Hospital, Boston, Massachusetts, United States
Background

PTEN is a lipid/tyrosine phosphatase that modulates various cellular processes including growth, survival and metabolism. Though the antagonistic effects of cytoplasmic PTEN on phosphatidylinositol-3-kinase (PI3K) is well defined, the function of nuclear PTEN is not known. Some studies have demonstrated that nuclear PTEN regulates DNA damage response followed by genotoxic stress and maintains genomic stability. In this study, we investigated the function of nuclear PTEN in renal epithelial cells followed by DNA damage in vitro and in vivo.

Methods

HK2 cells were treated with aristolochic acid (AA) for 48 hrs and cell cycle and nuclear PTEN was assessed. HEK293 cells stably expressing wild-type-GFP-PTEN, NLS-GFP-PTEN, mutant (NLS-GFP-C124S-PTEN) were developed and treated with 5 mg/ml AA and 10 μM cisplatin for 48 hour and cell cycle analysis was performed. Bilateral ischemia/reperfusion (IR: 20 min) was performed in C57B6 mice and mice were sacrificed at 21 days post IR. Kidney fibrosis was evaluated by Masson’s Trichrome and alpha-smooth muscle actin (α-SMA) staining. Immunostaining of PTEN was performed.

Results

HK2 cells displayed elevated nuclear PTEN localization following AA treatment. Cells stably expressing cytoplasmic PTEN exhibited G2/M arrest, while cells expressing nuclear PTEN rather displayed G1/S arrest. In mice, proximal tubular cells in fibrotic kidneys displayed elevated levels of nuclear PTEN staining.

Conclusion

Nuclear PTEN induces cell cycle arrest and is elevated after DNA damage in tubular epithelial cells in vitro and in vivo.