N-VEGF, the forgotten isoform of VEGF-A, activate cellular stress survival circuits

Vascular Endothelial Growth Factor A (VEGF-A) is a major angiogenesis stimulator in response to hypoxia. Its first exon possesses an elongated 59 Untranslated Region (59UTR) and two Internal Ribosome Entry Sites (IRESs), enabling translation under hypoxia. It also encodes a 180 aa peptide that is in-frame with the classic coding region of VEGF-A. Upon hypoxia, Long VEGF-A (L-VEGF) is translated from this reading-frame concomitant with canonical VEGF-A isoforms. L-VEGF is proteolytically cleaved upstream to the VEGF-A translation initiation site to generate N-VEGF, which under hypoxia shuttles to cells nuclei. Here we show that hypoxia-independent nuclear mobilization of N-VEGF into NIH3T3 cells nuclei followed by RNA-seq leads to the identification of induced key genes associated with angiogenesis, cellular maintenance, and survival. Conversely, CRISPR-Cas9 mediated deletion of N-VEGF followed by RNA-Seq analysis underlined cells fragility under hypoxia supported by experimentations. This novel data highlights the role of this non-canonical VEGF-A isoform in potentiating the initial steps of angiogenesis along with cell survival circuits.