Loss of the RNA helicase Dhx15 impairs endothelial energy metabolism, lymphatic drainage and tumor metastasis in mice

DHX15 is an ATP-dependent RNA helicase involved in pre-mRNA splicing and a downstream substrate for Akt1, which plays a significant role in vascular biology. The aim of this study was to explore the regulatory function of DHX15 over the vasculature and endothelial cell biology. Results: DHX15-/- was lethal in mouse and zebrafish embryos. DHX15-/- zebrafish also showed an undeveloped parachordal line, which leads to the formation of lymphatic structures. DHX15+/- mice triggered lower vascular network density and impaired lymphatic function postnatally. Transcriptome and proteome analysis of DHX15 silenced LEC revealed alterations in the glycolysis and gluconeogenesis pathways. The validation of these results demonstrated an uncoupling of the glycolysis with the oxidation of pyruvate in the mitochondria and a lower activity of the Complex I, resulting in lower cellular ATP production. Noteworthy, DHX15+/- mice partially inhibited primary tumor growth and reduced lung metastasis after injection of LLC1 tumor cells.