Aiming to identify factors underlying podocytes loss, the inventors revealed a markedly decreased expression of Vasorin (VASN) using comparative deep RNA sequencing of microdissected glomeruli from controls and patients diagnosed with FSGS or crescentic glomerulonephritis (CGN), that they further confirmed by in situ hybridization and immunohistochemistry. In particular, the inventors found that VASN is mainly expressed in podocytes during health. Furthermore, the inventors found that the level of glomerular or podocyte expression of the VASN gene depends on the kind of glomerular disease considered, suggesting this could be a helpful biomarker for differential diagnosis or outcome prediction.
Of specific interest, 1/ the expression of VASN is significantly less in kidneys from patients suffering from secondary FSGS or anti-neutrophil cytoplasmic antibodies (ANCA) associated crescentic glomerulonephritis than in control normal kidneys or minimal change disease (MN), suggesting that low VASN abundance would predict poor outcome. 2/ Podocyte expression of the VASN gene is significantly less in secondary FSGS than in primary FSGS. 3/ Podocyte expression of the VASN gene is significantly less in FSGS (primary and secondary) than in MCD cases. 4/ Podocyte or glomerular expression of the VASN gene is increased substantially in kidneys biopsies diagnosed with membranous nephropathy (MN), minimal change disease (MCD), and lupus nephritis (LN) as compared with controls and FSGS, suggesting that this could be used to discriminate disease types, causes, outcome, or response to therapy.
Accordingly, the present invention relates to the use of VASN as a biomarker and a biotarget for kidney diseases.