Downregulation of renal tubular Wnt/β-catenin signaling by Dickkopf-3 induces tubular cell death in proteinuric nephropathy

Cell Death Dis. 2016 Mar 24;7(3):e2155. doi: 10.1038/cddis.2016.62.

Abstract

Studies on the role of Wnt/β-catenin signaling in different forms of kidney disease have yielded discrepant results. Here, we report the biphasic change of renal β-catenin expression in mice with overload proteinuria in which β-catenin was upregulated at the early stage (4 weeks after disease induction) but abrogated at the late phase (8 weeks). Acute albuminuria was observed at 1 week after bovine serum albumin injection, followed by partial remission at 4 weeks that coincided with overexpression of renal tubular β-catenin. Interestingly, a rebound in albuminuria at 8 weeks was accompanied by downregulated tubular β-catenin expression and heightened tubular apoptosis. In addition, there was an inverse relationship between Dickkopf-3 (Dkk-3) and renal tubular β-catenin expression at these time points. In vitro, a similar trend in β-catenin expression was observed in human kidney-2 (HK-2) cells with acute (upregulation) and prolonged (downregulation) exposure to albumin. Induction of a proapoptotic phenotype by albumin was significantly enhanced by silencing β-catenin in HK-2 cells. Finally, Dkk-3 expression and secretion was increased after prolonged exposure to albumin, leading to the suppression of intracellular β-catenin signaling pathway. The effect of Dkk-3 on β-catenin signaling was confirmed by incubation with exogenous Dkk-3 in HK-2 cells. Taken together, these data suggest that downregulation of tubular β-catenin signaling induced by Dkk-3 has a detrimental role in chronic proteinuria, partially through the increase in apoptosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Animals
  • Apoptosis*
  • Cell Line
  • Chemokines
  • Gene Expression Regulation
  • Humans
  • Intercellular Signaling Peptides and Proteins / genetics
  • Intercellular Signaling Peptides and Proteins / metabolism*
  • Kidney Diseases / genetics
  • Kidney Diseases / metabolism*
  • Kidney Diseases / pathology
  • Kidney Tubules / metabolism*
  • Kidney Tubules / pathology
  • Mice
  • Proteinuria / genetics
  • Proteinuria / metabolism*
  • Proteinuria / pathology
  • Wnt Signaling Pathway*
  • beta Catenin / genetics
  • beta Catenin / metabolism*

Substances

  • Adaptor Proteins, Signal Transducing
  • Chemokines
  • DKK3 protein, human
  • Dkk3 protein, mouse
  • Intercellular Signaling Peptides and Proteins
  • beta Catenin