LncRNA TUG1 Repressed Angiogenesis by Promoting the Ubiquitination of HuR and Inhibiting Its Nuclear Translocation in Cerebral Ischemic Reperfusion Injury

Abstract Although both Taurine Upregulated Gene 1(TUG1) and Human Antigen R (HuR) play significant regulatory roles in Cerebral Ischemic Reperfusion Injury (CIRI), their potential pro‐angiogenesis mechanisms in CIRI remain unclear. Methods: Herein, the biological roles of TUG1 and HuR in angiogenesis are first confirmed. Following that, HuR‐binding VEGFA mRNAs are identified via the Fluorescence In Situ Hybridization (FISH), RNA Immunoprecipitation (RIP), and Cross‐Linking Immunoprecipitation (CLIP) assays. Actinomycin D and polysomal assays are also employed to confirm VEGFA mRNA stability. The co‐localization of TUG1 with HuR is confirmed using FISH, while the RIP and RNA pull‐down assays are employed to elucidate their interplay. The direct binding between TUG1 and HuR is confirmed through the CLIP assay. Co‐Immunoprecipitation (Co‐IP) and rescue experiments are performed to further elucidate TUG1‐HuR interactions. Results: While TUG1 repressed angiogenesis and aggravated CIRI, HuR exerted contrary effects. Specifically, HuR bound directly to VEGFA mRNA, a phenomenon that enhanced VEGFA mRNA stability. Conversely, TUG1 binds to HuR directly, inhibiting its nuclear translocation and promoting its ubiquitination, ultimately reducing VEGFA mRNA stability. Conclusions: It is found that TUG1 can inhibit angiogenesis in CIRI through the HuR/VEGFA mRNA axis.