Abstract
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.
Original language | English (US) |
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Pages (from-to) | 1681-1693 |
Number of pages | 13 |
Journal | Molecular Therapy |
Volume | 27 |
Issue number | 9 |
DOIs | |
State | Published - Sep 4 2019 |
Keywords
- TGF-β
- animal models
- arteriovenous fistula
- chronic kidney disease
- miR-21
- vascular remodeling
ASJC Scopus subject areas
- Molecular Medicine
- Molecular Biology
- Genetics
- Pharmacology
- Drug Discovery