MicroRNA‐31 is a positive modulator of endothelial–mesenchymal transition and associated secretory phenotype induced by TGF‐β

Abstract

Transforming growth factor‐β (TGF‐β) plays central roles in endothelial–mesenchymal transition (EndMT) involved in development and pathogenesis. Although EndMT and epithelial–mesenchymal transition are similar processes, roles of microRNAs in EndMT are largely unknown. Here, we report that constitutively active microRNA‐31 (miR‐31) is a positive regulator of TGF‐β‐induced EndMT. Although the expression is not induced by TGF‐β, miR‐31 is required for induction of mesenchymal genes including α‐SMA, actin reorganization and MRTF‐A activation during EndMT. We identified VAV3, a regulator of actin remodeling and MRTF‐A activity, as a miR‐31 target. Global transcriptome analysis further showed that miR‐31 positively regulates EndMT‐associated unique secretory phenotype (EndMT‐SP) characterized by induction of multiple inflammatory chemokines and cytokines including CCL17, CX3CL1, CXCL16, IL‐6 and Angptl2. As a mechanism for this phenomenon, TGF‐β and miR‐31 suppress Stk40, a negative regulator of NF‐κB pathway. Interestingly, TGF‐β induces alternative polyadenylation (APA)‐coupled miR‐31‐dependent Stk40 suppression without concomitant miR‐31 induction, and APA‐mediated exclusion of internal poly(A) sequence in Stk40 3′UTR enhances target efficiency of Stk40. Finally, miR‐31 functions as a molecular hub to integrate TGF‐β and TNF‐α signaling to enhance EndMT. These data confirm that constitutively active microRNAs, as well as inducible microRNAs, serve as phenotypic modifiers interconnected with transcriptome dynamics during EndMT.

Deletion of Stk40 impairs definitive erythropoiesis in the mouse fetal liver

“…35 This mechanism is also conserved in the endothelial–mesenchymal transition and in associated secretory phenotype induced by TGF- β . 36 Recently, STK40 was reported to suppress the NF- κ B pathway involved in human keratinocyte viability, migration and apoptosis. 37 Therefore, Stk40 may have a conserved inhibitory role of cytokine-induced NF- κ B signaling independent of cell types and contexts.…”

Intracellular and extracellular TGF-β signaling in cancer: some recent topics

“…TGF-β-induced EndMT is also regulated by multiple miRNAs. Activation of some miRNAs, such as miR-31, is required for TGF-β-induced EndMT in MS-1 mouse pancreatic microvascular endothelial cells [79].…”

Regulation of TGF-β-mediated endothelial-mesenchymal transition by microRNA-27

“…In addition, several studies have described roles of miRNAs in endothelial-mesenchymal transition (EndMT), which is important for heart development and various pathological processes (2). We have previously reported that transforming growth factor-β (TGF-β) induces mesenchymal genes including α-smooth muscle actin (α-SMA) by activating Rho signals and myocardin-related transcription factor A (MRTF-A), and that constitutively active miR-31 is a positive regulator of TGF-β-induced EndMT and EndMT-associated secretory phenotype (EndMT-SP) in MS-1 mouse pancreatic microvascular endothelial cells (2, 3). …”

“…In order to identify miR-27 targets during TGF-β-mediated EndMT at a transcriptome-wide level, we analysed the RNAseq data using MS-1 cells treated with miR-27b inhibitor and/or TGF-β, reported in our previous study (3). In consistent with widespread inhibitory effects of miRNAs on target gene expression, mRNA levels of potential miR-27 target genes with both conserved and poorly conserved target sites generally increased by miR-27 silencing (Fig.…”

“…Although miR-31 is required for induction of EndMT-SP, i.e. induction of multiple inflammatory chemokines and cytokines including CCL17, CX3CL1, IL-6 and Angptl2 (3), the effects of miR-27 inhibition on EndMT-SP were weak relative to miR-31 inhibition (Supplementary Fig. S2).…”