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Kidney Week

Abstract: FR-PO566

Manipulation of Autophagy in PKD Mice

Session Information

Category: Genetic Diseases of the Kidneys

  • 1201 Genetic Diseases of the Kidneys: Cystic

Authors

  • Atwood, Daniel, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
  • Chaudhary, Anjana, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
  • He, Zhibin, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
  • Oto, Ozgur Akin, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
  • Edelstein, Charles L., University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
Background

2-Deoxyglucose (2DG) and Chloroquine (CHLQ) are known to potentially induce or inhibit autophagy, respectively. Aim of the study was to determine the effect of pharmacological and genetic manipulations of autophagy on tubular cell proliferation and cyst growth.

Methods

Pkd1RC/RC (RC) male mice. 2DG (100 mg/kg) or CHLQ (60 mg/kg) from 50 - 120d of age. Kidney specific Pkd1, Atg7 double knockout mice generated by Ksp 1.3 Cre-lox recombination. Autophagic flux measured by increase in LC3-II (autophagosomes) with the lysosomal inhibitor, bafilomycin. Autophagy proteins measured by immunoblot. Cyst index (%) number and area determined on kidney cross sections by a computerized algorithm.

Results

See table. 2DG significantly reduced two kidney/body weight ratio (2K/BW), cyst index, cyst count, cyst area, BUN. 2DG significantly (P<0.05) reduced PCNA + cells lining cysts. 2DG decreased autophagy-related proteins (ATG12-5 complex, ATG3) and suppressed autophagic flux in RC kidneys. p-ERK and p-AMPK known to activate autophagy were decreased by 2DG. 2DG from 150-350d of age (later stage of PKD) had no effect on cyst growth. CHLQ had no effect on PKD or proliferation in the cells lining the cysts. CHLQ resulted in decreased expression of pBeclin (critical regulator of autophagy) and suppressed autophagic flux in RC kidneys. Next autophagy (ATG7) was knocked out in PKD mice. In a rapid PKD model, 2K/BW and BUN at 28 d old was the same in Pkd-/- vs Pkd1-/- ATG+/- vs Pkd1-/- ATG7-/- mice. In a slow PKD model, at 120 d, double knockout RC ATG7 mice had higher cyst indices than RC mice.

Conclusion

2DG suppressed autophagy, decreased proliferation, slowed PKD and improved kidney function. CHLQ suppressed autophagy but had no effect on PKD. Knockout of autophagy (ATG7) had no effect on PKD in a rapid severe model and worsened PKD in a slowly progressive model. Pharmacological suppression of autophagy had variable effects on proliferation and cyst growth and genetic knockout of autophagy worsened PKD in a slowly progressive PKD model.

Cyst indices
 Veh2DGVehCHLQPkd1-/-Pkd1-/-ATG7+/-Pkd1-/-ATG7-/-RCRC ATG7-/-
2K/BW (%)2.42*2.22.53935372.23.3*
Cyst index84*1612NDNDND1321*
Cyst No211161*233190NDNDND197455*
Cyst size μm264145385*85008647NDNDND67946492
BUN3527*3327777975  

ND=Not determined as kidney completely replaced by cysts. *P<0.05

Funding

  • Veterans Affairs Support