Mutant U2AF1-induced differential alternative splicing causes an oxidative stress in bone marrow stromal cells

Abstract

Alternative splicing (AS) is a critical regulatory process of gene expression. In bone marrow microenvironment, AS plays a critical role in mesenchymal stem cells fate determination by forming distinct isoforms of important regulators. As a spliceosome factor, U2AF1 is essential for the catalysis of pre-mRNA splicing, and its mutation can cause differential AS events. In the present study, by forced expression of mutant U2AF1 (U2AF1S34F) in the mouse bone marrow stroma OP9 cells, we determine AS changes in U2AF1S34F transduced OP9 cells and investigate their role in stroma cell biological functions. We find that abundant differential RNA splicing events are induced by U2AF1S34F in OP9 cells. U2AF1S34F causes increased generation of hydrogen peroxide, promotes production of cytokines and chemokines. U2AF1S34F transduced OP9 cells also exhibit dysfunction of mitochondria. RNA-seq data, gene ontology (GO), and gene set enrichment analysis reveal that differentially expressed genes downregulated in response to U2AF1S34F are enriched in peroxisome component and function. U2AF1S34F can also cause release of hydrogen peroxide from OP9 cells. Furthermore, we investigate the influence of U2AF1S34F-induced oxidative stress in stromal cells on hematopoietic cells. When co-culturing mouse bone marrow mononuclear cells with OP9 cells, the U2AF1S34F expressing OP9 cells induce phosphorylation of histone H2AX in hematopoietic cells. Collectively, our results reveal that mutant U2AF1-induced differential AS events cause oxidative stress in bone marrow stromal cells and can further lead to DNA damage and genomic instability in hematopoietic cells.

The Biological and Clinical Consequences of RNA Splicing Factor U2AF1 Mutation in Myeloid Malignancies

“…Expression of the U2AF1 S34F mutant in mouse bone marrow stroma OP9 cells induces the release of hydrogen peroxide, cytokines, and chemokines. U2AF1 S34F OP9 cells exhibit mitochondrial dysfunction, oxidative stress, DNA damage, and genomic instability [ 63 ]. Nonsense-mediated mRNA decay (NMD) is an RNA surveillance process that eliminates nonsense mRNAs produced by splicing dysregulation.…”

Transcriptomic landscape of human induced pluripotent stem cell-derived osteogenic differentiation identifies a regulatory role of KLF16

“…5b; Supplementary Table 6). To the best of our knowledge, only six SFs (U2AF1, SF3b4, HnRNPL, SRSF1, SRSF2, and DDX17) have been revealed to be associated with osteogenesis (He et al, 2022; Jia et al, 2019; Liu et al, 2021; Watanabe et al, 2007; Yi et al, 2019), and five of them except U2AF1 were found to be differentially expressed (top 62 up-regulated and top 12 down-regulated) during osteogenic differentiation in our datasets (Supplementary Table 6). U2AF1 was not a DEG, but U2AF1L4 , predicted to be part of H2AF complex, was ranked as the top seventh down-regulated gene.…”

High-Altitude Stress Orchestrates mRNA Expression and Alternative Splicing of Ovarian Follicle Development Genes in Tibetan Sheep

“…Alternative splicing facilitates diversification of the transcriptome and proteome by generating distinct mRNA isoforms [ 10 ]. Alternative splicing has been reported to involve cold stress, salt stress, and nutrient stress [ 12 , 13 , 14 , 15 ]. However, how AS contributes to high-altitude stress is largely unexplored.…”