Abstract: TH-PO1074
Sulfatases, in Particular SULF1, Are Important for the Integrity of the Glomerular Filtration Barrier in Zebrafish
Session Information
- Glomerular Diseases: Podocyte Biology - I
November 07, 2019 | Location: Exhibit Hall, Walter E. Washington Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1204 Podocyte Biology
Authors
- Schenk, Heiko Joachim, Hannover Medical School, Hannover, Germany
- Masseli, Anna Katharina, Hannover Medical School, Hannover, Germany
- Schroder, Patricia Ann, Mount Desert Island Biological Laboratory, Salisbury Cove, Maine, United States
- Bolanos-Palmieri, Patricia, University of Erlangen-Nurnberg, Erlangen, Germany
- Hegermann, Jan, Medizinische Hochschule Hannover, Hannover, Germany
- Braesen, Jan H., Medizinische Hochschule Hannover, Hannover, Germany
- Haller, Hermann G., Hannover Medical School, Hannover, Germany
Group or Team Name
- Haller Lab
Background
6-O-endosulfatases (sulfs) are important enzymatic components involved in the regulation of heparan sulfate by altering the sulfatation pattern. Specifically in the kidney, sulfs have been implicated in the glomerular podocyte-endothelial cell crosstalk and in the preservation of the glomerular filtration barrier (GFB) in different mouse models. Since it has been shown that in zebrafish larvae, Sulf1, Sulf2a, and Sulf2b are expressed in the pronephric kidney we set out to establish if a reduction in sulf expression leads to GFB dysfunction.
Methods
To evaluate the integrity of the GFB, we measured a GFP-tagged vitamin D binding protein derived from Tg(l-fabp:eGFP-DBP) zebrafish in the retinal vessel plexus of the zebrafish larvae at 96 hpf. Sulf-deficiency was induced using different morpholinos. The integrity of the GFB was evaluated by electron microscopy. Paraffin sections of sulf-deficient larvae were analyzed using immunofluorescence microscopy. Dextran microinjections and in vivo confocal imaging of the vasculature using Tg(flk:mcherry) larvae were carried out.
Results
Here, we show that a reduced sulf expression following MO-knockdown in zebrafish larvae promotes damage to the GFB leading to renal plasma protein loss from the circulation. Moreover, a combined knockdown of Sulf1, Sulf2a and Sulf2b is associated with severe morphologic changes including narrowing of the fenestration between glomerular endothelial cells as well as thickening of the glomerular basement membrane, and podocyte foot process effacement; suggesting that glomerular damage is an underlying cause of the circulatory protein loss observed after MO injection. Additionally, we show that a decrease in sulf expression reduces the bioavailability of VegfA in the glomerulus of the pronephros, which may contribute to the structural changes observed in the glomeruli of morphant fish. Furthermore, consistent with previous results, knockdown of the sulfs is associated with arteriovenous malformations in particular in the tail region of the larvae.
Conclusion
Overall, taken together our results suggest that 6-O-endosulfatases are important in the preservation of GFB integrity and a reduction in their expression levels induces phenotypic changes that are indicative of renal protein loss.