Changes of transcriptome in endothelial cells from kidney with tubule-specific conditional Vhlh gene knockout (Hoxb7-Cre-GFP; VhlhloxP/loxP), compared with wild-type.

Clear-cell renal cell carcinoma (ccRCC) is the most prevalent histological subtype of RCC in which more than 80% of ccRCC cases are associated with early inactivation of von Hippel-Lindau (VHL) tumor suppressor gene. We have generated a knockout mouse strain in which mouse allele of VHL (Vhlh) is conditionally deleted in the kidney epithelium (cortical tubules, collecting ducts and ascending Loops of Henle). These knockout mice showed high penetrance of inflammation and fibrosis in the kidney in addition to hyperplasia and the appearance of transformed clear cells. These results support the concept of tumor-promoting inflammation. Surprisingly, we found that the expression of pJNK, a marker of inflammation, was expressed in endothelial cells (ECs) in Vhlh mutant tissue although the knockout was in epithelial cells not in endothelial cells. The result indicated the important role of ECs in the initiation tumor progression. Therefore, the aim of this study is to investigate the molecular changes of ECs in the VHL mutant microenvironment. ECs from kidney of 3-month old male mice of mutant (Hoxb7-Cre-GFP-VhlhloxP/loxP, named ECs-KO) and control wildtype (Hoxb7-Cre-GFP, named ECs-WT) were isolated by anti-Cd31 antibody-conjugated magnetic beads. Total mRNAs of these isolated ECs were extracted immediately without additional culturing to capture as close as possible the in vivo molecular profile of ECs.