Short-term hypoxia triggers ROS and SAFB mediated nuclear matrix and mRNA splicing remodeling

• Published in: Redox biology 2022-12, Vol.58, p.102545-102545, Article 102545
• Main Authors: Taze, Chrysa, Drakouli, Sotiria, Samiotaki, Martina, Panayotou, George, Simos, George, Georgatsou, Eleni, Mylonis, Ilias
• Format: Article
• Language: English
• Subjects: Cell Hypoxia - genetics; Humans; Hypoxia; Hypoxia - genetics; Hypoxia - metabolism; Hypoxia-Inducible Factor 1, alpha Subunit - metabolism; Matrix Attachment Region Binding Proteins - genetics; Matrix Attachment Region Binding Proteins - metabolism; Nuclear matrix; Nuclear Matrix - metabolism; Nuclear Matrix-Associated Proteins - genetics; Nuclear Matrix-Associated Proteins - metabolism; Protein Serine-Threonine Kinases; Reactive Oxygen Species - metabolism; Receptors, Estrogen - genetics; Receptors, Estrogen - metabolism; Research Paper; RNA, Messenger - metabolism; SAFB; Splicing; Vascular Endothelial Growth Factor A - genetics; Vascular Endothelial Growth Factor A - metabolism; VEGFA
• ISSN: 2213-2317; 2213-2317
• DOI: 10.1016/j.redox.2022.102545

The cellular response to hypoxia, in addition to HIF-dependent transcriptional reprogramming, also involves less characterized transcription-independent processes, such as alternative splicing of the VEGFA transcript leading to the production of the proangiogenic VEGF form. We now show that this event depends on reorganization of the splicing machinery, triggered after short-term hypoxia by ROS production and intranuclear redistribution of the nucleoskeletal proteins SAFB1/2. Exposure to low oxygen causes fast dissociation of SAFB1/2 from the nuclear matrix, which is reversible, inhibited by antioxidant treatment, and also observed under normoxia when the mitochondrial electron transport chain is blocked. This is accompanied by altered interactions between SAFB1/2 and the splicing machinery, translocation of kinase SRPK1 to the cytoplasm, and dephosphorylation of RS-splicing factors. Depletion of SAFB1/2 under normoxia phenocopies the hypoxic and ROS-mediated switch in VEGF mRNA splicing. These data suggest that ROS-dependent remodeling of the nuclear architecture can promote production of splicing variants that facilitate adaptation to hypoxia. [Display omitted] •Hypoxia-induced ROS production causes dissociation of SAFB1/2 from nuclear matrix.•Hypoxic ROS production causes remodeling of splicing apparatus.•Remodeling of splicing machinery in hypoxia induces proangiogenic VEGFa production.