Modified scanning electron microscopy reveals pathological crosstalk between endothelial cells and podocytes in a murine model of membranoproliferative glomerulonephritis

This study evaluated endothelial cells and podocytes, both being primary components of the glomerular filtration barrier, in the progression of membranoproliferative glomerulonephritis (MPGN) using modified scanning electron microscopy (mSEM) analysis. BXSB/MpJ-Yaa model mice exhibited autoimmune-mediated MPGN characterised by elevated serum autoantibody levels, albuminuria, renal dysfunctional parameters, and decreased glomerular endothelial fenestrations (EF) and podocyte foot process (PFP) effacement with immune cell infiltration. Similar to transmission electron microscopy, mSEM revealed a series of pathological changes in basement membrane and densities of EF and PFP in BXSB/MpJ-Yaa compared with control BXSB/MpJ at different stages. Further, immunopositive area of endothelial marker (CD34), podocyte functional molecules (Nephrin, Podocin, Synaptopodin, and Wilms’ tumour 1 (WT1)), and vascular endothelial growth factor A (VEGF A) significantly decreased in the glomerulus of BXSB/MpJ-Yaa compared with BXSB at final stage. The indices of glomerular endothelial injuries (EF density and immunopositive area of CD34 and VEGF A) and podocyte injuries (PEP density and immunopositive area of podocyte functional molecules) were also significantly correlated with each other and with indices of autoimmune disease and renal dysfunction. Thus, our results elucidated the pathological crosstalk between endothelial cells and podocytes in MPGN progression and the usefulness of mSEM for glomerular pathological analysis.