High glucose induces an activated state of partial epithelial-mesenchymal transition in human primary tubular cell cultures.

Tubulointerstitial fibrosis is observed in diabetic nephropathy. It is still debated whether tubular cells, undergoing epithelial-mesenchymal transition (EMT) in high glucose (HG) conditions, may contribute to interstitial fibrosis development. In this study, we investigated the phenotypic and molecular EMT-like changes and the alteration of inflammatory and fibrogenic secretome induced by HG in human primary tubular cell cultures. Taking advantage of this in vitro cell model composed of proximal and distal tubular cells, we showed that HG-treated tubular cells acquired a fibroblast-like morphology with increased cytoplasmic stress fibers, maintaining the expression of the epithelial markers specific of proximal and distal tubular cells. HG increased Snail1, miRNA210 and Vimentin mesenchymal markers, decreased N-cadherin expression and migration ability of primary tubular cells, while E-cadherin expression and focal adhesion distribution were not affected. Furthermore, HG treatment of tubular cells altered the inflammatory cytokine secretion creating a secretome able to enhance the proliferation and migration of fibroblasts. Our findings show that HG promotes an activated state of partial EMT in human tubular primary cells and induces a pro-inflammatory and pro-fibrogenic microenvironment, supporting the active role of tubular cells in diabetic nephropathy onset.

The cross-talk between Abl2 tyrosine kinase and TGFß1 signalling modulates the invasion of clear cell Renal Cell Carcinoma cells.

Clear cell Renal Cell Carcinoma (ccRCC) is the most common and metastatic urological cancer. Molecular players of ccRCC progression and metastasis are not completely known. Here, using primary cell cultures from patients' specimens, we found that TGFß1/Smad signalling is more activated in high versus low grade ccRCC and inversely correlates with Abl2 tyrosine kinase protein expression. TGFß1 treatment increased ubiquitination and degradation of Abl2 protein in ccRCC cell lines by TGFß1/Smad pathway activation and reactive oxygen species production. 3D invasion and matrix degradation assays showed that Abl2 promoted TGFß1-induced ccRCC cell invasion and maturation of invadopodia, a hallmark of tumour invasion and metastasis. Our findings define Abl2 as a new downstream molecule of TGFß1 signalling and putative target to counteract advanced ccRCC.