The Role of MicroRNA-21 in Venous Neointimal Hyperplasia: Implications for Targeting miR-21 for VNH Treatment

• Published in: Molecular therapy 2019-09, Vol.27 (9), p.1681-1693
• Main Authors: Kilari, Sreenivasulu, Cai, Chuanqi, Zhao, Chenglei, Sharma, Amit, Chernogubova, Ekaterina, Simeon, Michael, Wu, Chin-Cheng, Song, Hsiang-Lin, Maegdefessel, Lars, Misra, Sanjay
• Format: Article
• Language: English
• Subjects: animal models; Animals; Apoptosis - genetics; arteriovenous fistula; Arteriovenous Fistula - genetics; Arteriovenous Fistula - pathology; Biomarkers; Cell culture; Cell Differentiation - genetics; Cell growth; Cell Proliferation; chronic kidney disease; Disease Models, Animal; DNA nucleotidylexotransferase; Experiments; Fibroblasts; Fibroblasts - metabolism; Fibrosis - genetics; Fistulae; Gene Expression; Gene Knockdown Techniques; Hemodialysis; Humans; Hybridization; Hyperplasia; Hypoxia; Hypoxia - genetics; Hypoxia - metabolism; Hypoxia-inducible factor 1; Hypoxia-inducible factor 1a; Hypoxia-inducible factors; Immunohistochemistry; Kidney diseases; Lentivirus - genetics; Male; Mice; MicroRNAs; MicroRNAs - genetics; miR-21; miRNA; Myofibroblasts - metabolism; Neointima - genetics; Neointima - pathology; Neointima - therapy; Original; Patients; PTEN protein; RNA Interference; RNA, Small Interfering - genetics; Smad2 protein; Smad3 protein; Smooth muscle; Studies; Tensin; TGF-β; Transduction, Genetic; Transforming growth factor-b1; vascular remodeling; Veins; Veins & arteries; Veins - metabolism; Veins - pathology; Virology
• ISSN: 1525-0016; 1525-0024
• DOI: 10.1016/j.ymthe.2019.06.011

The molecular mechanism of hemodialysis access arteriovenous fistula (AVF) failure due to venous neointimal hyperplasia (VNH) is not known. The role of microRNA-21 (miR-21) in VNH associated with AVF failure was investigated by performing in vivo and in vitro experiments. In situ hybridization results revealed that miR-21 expression increased and was associated with fibroblasts in failed AVFs from patients. In a murine AVF model, qRT-PCR gene expression results showed a significant increase in miR-21 and a decrease in miR-21 target genes in graft veins (GVs) compared to contralateral veins in mouse AVF. miR-21 knockdown in GVs was performed using a lentivirus-mediated small hairpin RNA (shRNA), and this improved AVF patency with a decrease in neointima compared to control GVs. Moreover, loss of miR-21 in GVs significantly decreased the Tgfβ1, Col-Ia, and Col-Iva genes. Immunohistochemistry demonstrated a significant decrease in myofibroblasts and proliferation with an increase in terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining in miR-21-knockdown vessels, along with a decrease in hypoxia-inducible factor-1 alpha (HIF-1α) and phospho-SMAD2 (pSMAD-2) and phospho-SMAD3 (pSMAD-3) and an increase in phosphatase and tensin homolog (PTEN) staining. Hypoxic fibroblast knockdown for miR-21 showed a significant decrease in Tgfβ-1 expression and pSMAD-2 and -3 levels and a decrease in myofibroblasts. These results indicate that miR-21 upregulation causes VNH formation by fibroblast-to-myofibroblast differentiation. About 50% of hemodialysis arteriovenous fistula (AVF) will fail within a year of placement. Novel strategies that can improve fistula patency are needed. The present study demonstrated a significant role of microRNA-21 in AVF failure, and its knockdown in outflow veins of AVF improved the AVF function and durability.