Background
Ischemia–reperfusion (I/R) injury in the heart triggers oxidative stress and alters post-transcriptional gene regulation. Reactive oxygen species (ROS) generated during oxidative stress induce RNA modifications such as 8-oxo-guanosine (o8G). Other modifications including 5-methylcytosine (m5C) and 7-methylguanosine (m7G) may also contribute to cardiac dysfunction. While the roles of individual RNA modifications in I/R injury are increasingly recognized, the global dynamics and crosstalk among these modifications under oxidative stress remain largely unexplored.
Methods
We performed high-throughput sequencing specific to each modification, integrated with mRNA transcriptome profiling of an IR injury mouse model. Differentially modified transcripts were subjected to GO and KEGG enrichment analyses to elucidate their functional relevance. Mechanistically, we demonstrated that RNA modification regulators with distinct functional roles can physically interact with each other, as shown by co-immunoprecipitation and immunofluorescence assays. Global changes in RNA modification levels under the model conditions were assessed using dot blot analysis. Furthermore, the regulatory effects of these enzymes on target mRNA stability were evaluated via Actinomycin D transcriptional inhibition assays.
Results
We found that the levels of all three modifications, m5C, m7G, and o8G were increased in IR by dot blot and observed a significant upregulation of three modification peaks under I/R by MeRIP-seq. Both m5C and o8G were predominantly enriched in CDS, while m7G displayed a dynamic redistribution. Our study focuses on the co-regulation crosstalk among three modifications. Functionally, singly or combinatorially modified transcripts were enriched in actin cytoskeleton regulation. Mechanistically, the transcripts of the regulators can be modified by each other and QKI can modulate the global modification level of o8G. QKI and YBX1 interact with each other to cooperatively stabilize ACTN4 mRNA, thereby maintaining cytoskeletal integrity.
Conclusion
Our results establish that QKI and YBX1 modulate the actin cytoskeleton via a coordinated network of m5C, m7G, and o8G in I/R injury.
扫码关注我们
求助内容:
应助结果提醒方式:
