Involvement of miR-190b in Xbp1 mRNA Splicing upon Tocotrienol Treatment.

ABSTRACT: We previously demonstrated that apoptosis induced by tocotrienols (? and ?T3) in HeLa cells is preceded by Ca²⁺ release from the endoplasmic reticulum. This event is eventually followed by the induction of specific calcium-dependent signals, leading to the expression and activation of the gene encoding for the IRE1? protein and, in turn, to the alternative splicing of the pro-apoptotic protein sXbp1 and other molecules involved in the unfolded protein response, the core pathway coping with EndoR stress. Here, we showed that treatment with T3s induces the expression of a specific set of miRNAs in HeLa cells. Data interrogation based on the intersection of this set of miRNAs with a set of genes previously differentially expressed after ?T3 treatment provided a few miRNA candidates to be the effectors of EndoR-stress-induced apoptosis. To identify the best candidate to act as the effector of the Xbp1-mediated apoptotic response to ?T3, we performed in silico analysis based on the evaluation of the highest ? in Gibbs energy of different mRNA-miRNA-Argonaute (AGO) protein complexes. The involvement of the best candidate identified in silico, miR-190b, in Xbp1 splicing was confirmed in vitro using T3-treated cells pre-incubated with the specific miRNA inhibitor, providing a preliminary indication of its role as an effector of EndoR-stress-induced apoptosis.

SUBMITTER: Ambra R 

PROVIDER: S-EPMC7795057 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature