Endothelial mitochondrial oxidative stress determines podocyte depletion in segmental glomerulosclerosis
Ilse Daehn, … , Borje Haraldsson, Erwin P. Bottinger
Ilse Daehn, … , Borje Haraldsson, Erwin P. Bottinger
Published March 3, 2014
Citation Information: J Clin Invest. 2014;124(4):1608-1621. https://doi.org/10.1172/JCI71195.
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Research Article Nephrology

Endothelial mitochondrial oxidative stress determines podocyte depletion in segmental glomerulosclerosis

Abstract

Focal segmental glomerular sclerosis (FSGS) is a primary kidney disease that is commonly associated with proteinuria and progressive loss of glomerular function, leading to development of chronic kidney disease (CKD). FSGS is characterized by podocyte injury and depletion and collapse of glomerular capillary segments. Progression of FSGS is associated with TGF-β activation in podocytes; however, it is not clear how TGF-β signaling promotes disease. Here, we determined that podocyte-specific activation of TGF-β signaling in transgenic mice and BALB/c mice with Adriamycin-induced glomerulosclerosis is associated with endothelin-1 (EDN1) release by podocytes, which mediates mitochondrial oxidative stress and dysfunction in adjacent endothelial cells via paracrine EDN1 receptor type A (EDNRA) activation. Endothelial dysfunction promoted podocyte apoptosis, and inhibition of EDNRA or scavenging of mitochondrial-targeted ROS prevented podocyte loss, albuminuria, glomerulosclerosis, and renal failure. We confirmed reciprocal crosstalk between podocytes and endothelial cells in a coculture system. Biopsies from patients with FSGS exhibited increased mitochondrial DNA damage, consistent with EDNRA-mediated glomerular endothelial mitochondrial oxidative stress. Our studies indicate that segmental glomerulosclerosis develops as a result of podocyte-endothelial crosstalk mediated by EDN1/EDNRA-dependent mitochondrial dysfunction and suggest that targeting the reciprocal interaction between podocytes and endothelia may provide opportunities for therapeutic intervention in FSGS.

Authors

Ilse Daehn, Gabriella Casalena, Taoran Zhang, Shaolin Shi, Franz Fenninger, Nicholas Barasch, Liping Yu, Vivette D’Agati, Detlef Schlondorff, Wilhelm Kriz, Borje Haraldsson, Erwin P. Bottinger

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Figure 7

Validation of in vivo results using a defined PodTgfbr1-derived podocyte and in mGEC coculture system.

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Validation of in vivo results using a defined PodTgfbr1-derived podocyte...
(A) Percentage increase of MitoSOX bright fluorescent mGECs after culture with Control-PSN or Dox-PSN (1 μg/ml) for 24 hours in the absence or presence of BQ-123 (1 ng/ml) or mitoTEMPO (5 μg/ml). (B) Immunofluorescence detection of 8-oxoG in mGECs cultured as described in A. (C) Double-immunofluorescence detection of 8-oxoG (green) and mitochondrial transcription factor A (red) in mGECs cocultured in Dox-PSN (arrows indicates colocalization). (D) OCR in mGECs cultured 24 hours with 100% Control-PSN or 50% or 100% Dox-PSN in the absence or presence of BQ-123 or mitoTEMPO. (E) Percentage increase of MitoSOX fluorescent mGECs transfected with control SCR siRNA or EDNRA siRNA and treated with EDN1 (200 nM), Dox-PSN, or Dox-PSN from EDN1 siRNA-transfected podocytes. (F) 8-oxoG immunofluorescence in mGECs transfected with control SCR siRNA or EDNRA siRNA and cultured 24 hours with either Control-PSN or Dox-PSN, as indicated. (G) NOS activity detected by DAF-FM fluorescence in mGECs in RPMI control media without or with L-NAME (100 μM) or in mGECs cultured for 24 hours with 100% Control-PSN or 50% to 100% Dox-PSN in absence or presence of BQ-123 or mitoTEMPO. (A, D, E, and G) Each bar represents n = 3; mean ± SEM. *P < 0.05 versus SN controls, #P < 0.05 versus RPMI controls, ##P < 0.05 versus Dox. Cocultures performed in 10% FCS. Original magnification, ×100 (B, C, and F).