Transient upregulation of EGR1 signaling enhances kidney repair by activating SOX9+ renal tubular cells

Theranostics. 2022 Jul 11;12(12):5434-5450. doi: 10.7150/thno.73426. eCollection 2022.

Abstract

Background: Acute kidney injury (AKI) is associated with damage to the nephrons and tubular epithelial cells (TECs), which can lead to chronic kidney disease and end-stage renal disease. Identifying new biomarkers before kidney dysfunction will offer crucial insight into preventive and therapeutic options for the treatment of AKI. Early growth response 1 (EGR1) has been found to be a pioneer transcription factor that can sequentially turn on/off key downstream genes to regulate whole-body regeneration processes in the leopard worm. Whether EGR1 modulates renal regeneration processes in AKI remains to be elucidated. Methods: AKI models of ischemia-reperfusion injury (IRI) and folic acid (FA) were developed to investigate the roles of EGR1 in kidney injury and regeneration. To further determine the function of EGR1, Egr1-/- mice were applied. Furthermore, RNA sequencing of renal TECs, Chromatin Immunoprecipitation (ChIP) assay, and Dual-luciferase reporter assay were carried out to investigate whether EGR1 affects the expression of SOX9. Results: EGR1 is highly expressed in the kidney after AKI both in humans and mice through analysis of the Gene Expression Omnibus (GEO) database. Furthermore, we verified that EGR1 rapidly up-regulates in the very early stage of IRI and nephrotoxic models of AKI, and validation studies confirmed the essential roles of EGR1 in renal tubular cell regeneration. Further experiments affirmed that genetic inhibition of Egr1 aggravates the severity of AKI in mouse models. Furthermore, our results revealed that EGR1 could increase SOX9 expression in renal TECs by directly binding to the promoter of the Sox9 gene, thus promoting SOX9+ cell proliferation by activating the Wnt/β-catenin pathway. Conclusions: Together, our results demonstrated that rapid and transient induction of EGR1 plays a renoprotective role in AKI, which highlights the prospects of using EGR1 as a potential therapeutic target for the treatment of AKI.

Keywords: Acute kidney injury (AKI); Early growth response 1 (EGR1); Regeneration; SOX9; Tubular epithelial cells (TECs).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Kidney Injury* / genetics
  • Acute Kidney Injury* / metabolism
  • Animals
  • Early Growth Response Protein 1* / genetics
  • Early Growth Response Protein 1* / metabolism
  • Epithelial Cells / metabolism
  • Humans
  • Kidney / metabolism
  • Kidney / pathology
  • Kidney Tubules* / metabolism
  • Kidney Tubules* / pathology
  • Mice
  • Mice, Inbred C57BL
  • Reperfusion Injury* / genetics
  • Reperfusion Injury* / metabolism
  • SOX9 Transcription Factor* / genetics
  • SOX9 Transcription Factor* / metabolism
  • Up-Regulation
  • Wnt Signaling Pathway

Substances

  • EGR1 protein, human
  • Early Growth Response Protein 1
  • Egr1 protein, mouse
  • SOX9 Transcription Factor
  • SOX9 protein, human
  • Sox9 protein, mouse