ADAM17 substrate release in proximal tubule drives kidney fibrosis
Eirini Kefaloyianni, Muthu Lakshmi Muthu, Jakob Kaeppler, Xiaoming Sun, Venkata Sabbisetti, Athena Chalaris, Stefan Rose-John, Eitan Wong, Irit Sagi, Sushrut S. Waikar, Helmut Rennke, Benjamin D. Humphreys, Joseph V. Bonventre, Andreas Herrlich
Eirini Kefaloyianni, Muthu Lakshmi Muthu, Jakob Kaeppler, Xiaoming Sun, Venkata Sabbisetti, Athena Chalaris, Stefan Rose-John, Eitan Wong, Irit Sagi, Sushrut S. Waikar, Helmut Rennke, Benjamin D. Humphreys, Joseph V. Bonventre, Andreas Herrlich
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Research Article Cell biology Nephrology

ADAM17 substrate release in proximal tubule drives kidney fibrosis

Abstract

Kidney fibrosis following kidney injury is an unresolved health problem and causes significant morbidity and mortality worldwide. In a study into its molecular mechanism, we identified essential causative features. Acute or chronic kidney injury causes sustained elevation of a disintegrin and metalloprotease 17 (ADAM17); of its cleavage-activated proligand substrates, in particular of pro-TNFα and the EGFR ligand amphiregulin (pro-AREG); and of the substrates’ receptors. As a consequence, EGFR is persistently activated and triggers the synthesis and release of proinflammatory and profibrotic factors, resulting in macrophage/neutrophil ingress and fibrosis. ADAM17 hypomorphic mice, specific ADAM17 inhibitor–treated WT mice, or mice with inducible KO of ADAM17 in proximal tubule (Slc34a1-Cre) were significantly protected against these effects. In vitro, in proximal tubule cells, we show that AREG has unique profibrotic actions that are potentiated by TNFα-induced AREG cleavage. In vivo, in acute kidney injury (AKI) and chronic kidney disease (CKD, fibrosis) patients, soluble AREG is indeed highly upregulated in human urine, and both ADAM17 and AREG expression show strong positive correlation with fibrosis markers in related kidney biopsies. Our results indicate that targeting of the ADAM17 pathway represents a therapeutic target for human kidney fibrosis.

Authors

Eirini Kefaloyianni, Muthu Lakshmi Muthu, Jakob Kaeppler, Xiaoming Sun, Venkata Sabbisetti, Athena Chalaris, Stefan Rose-John, Eitan Wong, Irit Sagi, Sushrut S. Waikar, Helmut Rennke, Benjamin D. Humphreys, Joseph V. Bonventre, Andreas Herrlich

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Figure 3

ADAM17ex/ex and ADAM17 PTC-KO mice are protected from UUO-induced fibrosis.

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ADAM17ex/ex and ADAM17 PTC-KO mice are protected from UUO-induced fibros...
Mice were subjected to UUO, and their kidneys were examined 7 or 14 days after ureteral ligation, as noted. (A) qPCR analysis of fibronectin or αSMA mRNA expression levels in whole kidneys of ex/ex or WT/WT mice at day 7, expressed as fold over respective sham-injured mice (n = 6). (B) The induction of fibronectin and αSMA in the injured kidney cortex of UUO-subjected WT/WT or ex/ex mice was examined by immunostaining (left: representative images; right: quantification; n = 6; scale bar: 50 μm). (C) Fibronectin protein expression at day 7 after ligation was examined by Western blot (top: sample blots; bottom: quantification; GAPDH was used as loading control; n = 3). (D) Masson’s trichrome staining in kidney cortex at day 7 or day 14 after ligation (left: representative images day 14; right: quantification; n = 5–6; scale bar: 100 μm). (E) qPCR analysis of fibronectin or αSMA mRNA expression levels in whole kidneys of UUO-subjected control (Cre WT/WT) or ADAM17 PTC-KO (Cre fl/fl) at day 7, expressed as fold over respective sham-injured mice (n = 3). (F) The induction of fibronectin and αSMA in the injured kidney cortex of UUO-subjected control (Cre WT/WT) or ADAM17 PTC-KO (Cre fl/fl) mice was examined at day 7 by immunostaining (left: representative images, right: quantification; n = 5; scale bar: 50 μm). (G) Fibronectin protein expression at day 7 after ligation was examined by Western blot (top: sample blots; bottom: quantification; GAPDH was used as loading control; n = 3). (H) Masson’s trichrome staining in kidney cortex at day 7 after ligation in control (Cre WT/WT) or ADAM17 PTC-KO (Cre fl/fl) mice (left: representative images; right: quantification; n = 6; scale bar: 100 μm). *P < 0.05; **P < 0.01; ***P < 0.001 as determined by an unpaired 2-tailed Student’s t test. ADAM17; a disintegrin and metalloprotease 17; FN1, fibronectin; MT, Masson’s trichrome; PTC-KO, proximal tubule cell KO; αSMA, alpha smooth muscle actin; UUO, unilateral ureteral obstruction; WB, Western blot.