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Kidney Week

Abstract: FR-PO191

ATF3 Ameliorates Ischemic Kidney Damage by Controlling the Cross-Talk Between Immune and Kidney Cells

Session Information

  • AKI: Mechanisms - II
    November 03, 2023 | Location: Exhibit Hall, Pennsylvania Convention Center
    Abstract Time: 10:00 AM - 12:00 PM

Category: Acute Kidney Injury

  • 103 AKI: Mechanisms

Authors

  • Paolini, Andrea, Albert-Ludwigs-Universitat Freiburg Universitatsklinikum Freiburg, Freiburg, Baden-Württemberg, Germany
  • Todkar, Abhijeet, Albert-Ludwigs-Universitat Freiburg Universitatsklinikum Freiburg, Freiburg, Baden-Württemberg, Germany
  • Wiegel, Johannes, Albert-Ludwigs-Universitat Freiburg Universitatsklinikum Freiburg, Freiburg, Baden-Württemberg, Germany
  • Yakulov, Toma Antonov, Albert-Ludwigs-Universitat Freiburg Universitatsklinikum Freiburg, Freiburg, Baden-Württemberg, Germany
  • Walz, Gerd, Albert-Ludwigs-Universitat Freiburg Universitatsklinikum Freiburg, Freiburg, Baden-Württemberg, Germany
Background

Acute kidney injury (AKI) is a leading cause of death. The molecular pathophysiological mechanisms of AKI remain only partially understood, and targeted therapies to facilitate recovery from renal failure are still elusive.

Methods

To find central signaling pathways that drive kidney regeneration, we performed single-cell RNA sequencing (scRNA-seq) after laser-induced injury of zebrafish pronephric tubules, and explored the function of Atf3 in three different Atf3-deletion models, subjecting Atf3f/f*Pax8-rtTA*TetO-Cre, Atf3f/f**Cx3cr1-Cre, and Atf3f/f*Ksp-Cre mice to unilateral nephrectomy followed by ischemia-reperfusion injury (IRI). To determine the role of ATF3 in IRI, kidney cells were subsequently analyzed by histology, flow cytometry, bulk-/scRNA-seq, and CUT&RUN experiments.

Results

Depletion of zebrafish atf3 by morpholino oligonucleotides compromised the repair process after pronephros injuries. While Pax8- or Cx3cr1-mediated deletion of Atf3 did not affect renal function, Ksp-Cre-mediated Atf3 loss intensified the renal failure after IRI in mice. The absence of Atf3 in distal nephron segments reduced the expression of crucial chemokines including Cxcl10, resulting in decreased numbers of infiltrating F4/80+ macrophages and deficient macrophage “M2” polarization. Using RNA sequencing and CUT&RUN techniques, we found that ATF3 directly regulates Umod (Uromodulin), and promotes its secretion via increased Kcnj1 (ROMK) expression after IRI. Gene Ontology enrichment analysis of the immune cell populations confirmed the downregulation of leukocyte migration, cytokine production, and cell-cell adhesion. CellChat analysis identified a weakened interaction between immune cells and the tubular epithelial cells of the thick ascending limb (TAL).

Conclusion

Ksp-Cre-mediated excision of Atf3, primarily affecting ATF3 production in the TAL, worsens renal failure after IRI. Loss of ATF3 affects the expression of several immune regulatory factors including Uromodulin, which is known to promote an anti-inflammatory macrophage phenotype. Our analyses reveal that ATF3 protects the kidney against ischemia by controlling the cross-talk between immune and kidney cells.

Funding

  • Government Support – Non-U.S.