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

Yuki Otani,Yaser Hosny Ali Elewa,Yasuhiro Kon,Marina Hosotani,Osamu Ichii,Md Abdul Masum,Teppei Nakamura

doi:10.1038/s41598-018-28617-1

Yuki Otani, Yaser Hosny Ali Elewa + Show 5 more

Open Access

https://doi.org/10.1038/s41598-018-28617-1

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Abstract

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.

Highlights

The mammalian kidney is generally considered a non-regenerative organ
Pathologies of glomerular endothelial cells (GECs) and their fenestration are associated with proteinuria and renal failure, which have been well characterized in preeclampsia and diabetes[10,11,12]
The ultrastructural quantitative analysis of the glomerulus, including enumeration of endothelial fenestrations (EFs) and podocyte foot process (PFP), is quite difficult, because scanning electron microscopy (SEM) reveals only the surface of GECs or podocytes, and the area is limited for transmission electron microscopy (TEM) observation

Summary

Introduction

The mammalian kidney is generally considered a non-regenerative organ. Recently, the incidence of kidney diseases, especially chronic kidney disease (CKD), has increased worldwide[1]. Limited information is available regarding the defective interactions between podocytes and glomerular endothelium during CKD pathogenesis, including MPGN revealed by combined ultrastructural and molecular approaches. The ultrastructural quantitative analysis of the glomerulus, including enumeration of endothelial fenestrations (EFs) and podocyte foot process (PFP), is quite difficult, because SEM reveals only the surface of GECs or podocytes, and the area is limited for TEM observation. These methodological limitations are common in basic and clinical studies, and are associated with difficulty in biopsy-based diagnosis and ultrastructural analysis of the glomerulus. The present study clearly revealed pathological correlations between the glomerular endothelial and podocyte injury in MPGN pathogenesis through a unique ultrastructural analysis and molecular quantitative analysis

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