TGFβ Triggers miR-143/145 Transfer From Smooth Muscle Cells to Endothelial Cells, Thereby Modulating Vessel Stabilization

Abstract

Rationale: The miR-143/145 cluster is highly expressed in smooth muscle cells (SMCs), where it regulates phenotypic switch and vascular homeostasis. Whether it plays a role in neighboring endothelial cells (ECs) is still unknown. Objective: To determine whether SMCs control EC functions through passage of miR-143 and miR-145. Methods and Results: We used cocultures of SMCs and ECs under different conditions, as well as intact vessels to assess the transfer of miR-143 and miR-145 from one cell type to another. Imaging of cocultured cells transduced with fluorescent miRNAs suggested that miRNA transfer involves membrane protrusions known as tunneling nanotubes. Furthermore, we show that miRNA passage is modulated by the transforming growth factor (TGF) β pathway because both a specific transforming growth factor-β (TGFβ) inhibitor (SB431542) and an shRNA against TGFβRII suppressed the passage of miR-143/145 from SMCs to ECs. Moreover, miR-143 and miR-145 modulated angiogenesis by reducing the proliferation index of ECs and their capacity to form vessel-like structures when cultured on matrigel. We also identified hexokinase II ( HKII ) and integrin β 8 ( ITGβ8 )—2 genes essential for the angiogenic potential of ECs—as targets of miR-143 and miR-145, respectively. The inhibition of these genes modulated EC phenotype, similarly to miR-143 and miR-145 overexpression in ECs. These findings were confirmed by ex vivo and in vivo approaches, in which it was shown that TGFβ and vessel stress, respectively, triggered miR-143/145 transfer from SMCs to ECs. Conclusions: Our results demonstrate that miR-143 and miR-145 act as communication molecules between SMCs and ECs to modulate the angiogenic and vessel stabilization properties of ECs.

MicroRNA in cardiovascular biology and disease

“…MiR-143 and miR-145 target hexokinase II (HKII) and integrin β 8 (ITGβ8) genes, respectively. 47 MiR-145 has been also implicated in the pathophysiology of atherosclerosis due to its effect on VSMC proliferation and phenotypic changes. In endothelial cells miR-143/145 expression is mediated by shear-responsive transcription factor -Kruppel like factor 2 (KLF2).…”

Endothelial and Smooth Muscle Cell Interactions in the Pathobiology of Pulmonary Hypertension

“…Notch signaling plays an important role during vascular development, and defects in this pathway may promote the development of PH (132,133). Interestingly, a recent study showed that miRNA in VSMCs may modulate the functions of EC through tunneling nanotubes formed between these two cell types (20). It clearly indicates the complexity of EC-VSMC communication.…”

“…However, there is increasing evidence that the relationship between the EC and the SMC is not a simple one-way interaction from the endothelium to the SMC; rather, there are complicated interactions between them (9-11). Moreover, the communication patterns are not limited to paracrine signaling; cross-talk through myoendothelial gap junctions (MEJs), extracellular vesicles (EVs), and other mechanisms is critically involved (12)(13)(14)(15)(16)(17)(18)(19)(20). These mechanisms operate in a complicated but co-ordinated manner to maintain the homeostasis of the pulmonary circulation.…”

MicroRNAs for Restenosis and Thrombosis After Vascular Injury

“…70 In addition, recent evidences demonstrated the existence of a cross talk between ECs and SMCs mediated by these miRNAs. 32,92 In particular, it was hypothesized that miR-143/145 could be transferred by linelike membrane tubes which directly connect cells, 92 as well as through the secretion of extracellular vesicles. 32 As described earlier, miRNA-mediated cell-to-cell communication was also described for miR-126, which is enriched in apoptotic bodies derived from ECs, and provides an athero-protective effect.…”