Murine Podocyte Membrane Proteomics

Podocytes are essential cells of the renal blood filter. They structurally compose the renal blood filter by interdigitating with neighboring podocytes by the means of a modified adherens junction, the slit membrane. In podocyte injury, loss of podocytes is a common feature. Podocyte loss could be mediated by the cleavage of podocyte cell adhesion molecules through the A Disintegrin and Metalloproteinase 10 (ADAM10). Here we show that ADAM10 is highly abundant at the site of blood filtration, namely at podocyte foot processes. Podocyte-expressed ADAM10 is not required for the development of the renal filter but plays a major role in podocyte injury. Following antibody-mediated injury, ADAM10 is upregulated in humans and mice. ADAM10 activity results in the cleavage of cell-cell adhesion molecules. This cleavage paves the way for an activation of the injury related Wnt/-catenin signaling pathway and for podocyte loss. We therefore conclude that ADAM10-mediated ectodomain shedding of injury-related cadherins drives podocyte injury. As part of this project, we have analyzed the membrane proteome of murin podocytes to evaluate the abundance of membrane bound proteases.