Increased plasma VEGF levels following ischemic preconditioning are associated with downregulation of miRNA-762 and miR-3072-5p.

Koji Ueno,Kimikazu Hamano,Masaya Takahashi,Tamami Nakamura,Yuriko Takeuchi,Noriyasu Morikage,Yuya Tanaka,Tohru Hosoyama,Daichi Kawamura,Makoto Samura

doi:10.1038/srep36758

Koji Ueno, Kimikazu Hamano + Show 8 more

Open Access

https://doi.org/10.1038/srep36758

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Journal: Scientific Reports	Publication Date: Dec 1, 2016
Citations: 37	License type: CC BY 4.0

Affiliation: Yamaguchi University

Abstract

Ischemic preconditioning (IPC) has protective effects against ischemia-perfusion injury of organs. In the present study, we investigated the associated mechanisms after performing remote IPC (rIPC) of lower limbs by clamping abdominal aorta in mice. Subsequent experiments showed decreased damage and paralysis of lower limbs following spinal cord injury (SCI). Concomitantly, plasma vascular endothelial growth factor (VEGF) levels were increased 24 h after rIPC compared with those in sham-operated animals. In subsequent microRNA analyses, thirteen microRNAs were downregulated in exosomes 24 h after rIPC. Further studies of femoral CD34-positive bone marrow (BM) cells confirmed downregulation of these seven microRNAs 24 h after rIPC compared with those in sham-operated controls. Subsequent algorithm-based database searches suggested that two of the seven microRNAs bind to the 3′ UTR of VEGF mRNA, and following transfection into CD34-positive BM cells, anti-miR-762, and anti-miR-3072-5p inhibitors led to increased VEGF concentrations. The present data suggest that rIPC transiently increases plasma VEGF levels by downregulating miR-762 and miR-3072-5p in CD34-positive BM cells, leading to protection against organ ischemia.

Highlights

IntroductionRIPC following SCI and show that remote IPC (rIPC) increases plasma VEGF concentrations and reduces the severity of paraplegia following SCI
RIPC following SCI and show that remote ischemic preconditioning (IPC) (rIPC) increases plasma VEGF concentrations and reduces the severity of paraplegia following SCI
Plasma VEGF levels were determined using enzyme-linked immunosorbent assay (ELISA) 24, 48, and 72 h after rIPC. These experiments showed significantly higher plasma VEGF levels in the rIPC-treated group than in the sham group 24 h after rIPC, VEGF concentrations did not differ between treatment groups 48 and 72 h after IPC (Fig. 2)

Summary

Introduction

RIPC following SCI and show that rIPC increases plasma VEGF concentrations and reduces the severity of paraplegia following SCI. After validating microarray data for exosome microRNAs, we identified microRNAs that are downregulated by rIPC. Target Scan algorithms showed that miR-762 and miR-3072-5p target the 3′UTR of VEGF mRNA and were downregulated after rIPC. IPC-induced expression levels of these microRNAs in CD34-positive BM cells from femurs were lower than those from sham-operated controls. VEGF secretions were increased in CD34-positive BM cells following treatment with anti-miR-762 and anti-miR-3072-5p inhibitors. The present data indicate that effective organ protection by rIPC reflects increased plasma VEGF concentrations following downregulation of miR-762 and miR-3072-5p in CD34-positive BM cells

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