Epigenetic down‐regulation of microRNA‐126 in scleroderma endothelial cells is associated with impaired responses to VEGF and defective angiogenesis

• Published in: Journal of cellular and molecular medicine Vol. 25; no. 14; pp. 7078 - 7088
• Main Authors: Wang, Yongqing, Sun, John, Kahaleh, Bashar
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01.07.2021; John Wiley and Sons Inc
• Subjects: Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Angiogenesis; Calcium-Binding Proteins - genetics; Calcium-Binding Proteins - metabolism; Cell adhesion & migration; Cells, Cultured; DNA Methylation; DNA sequencing; Down-Regulation; EGF Family of Proteins - genetics; EGF Family of Proteins - metabolism; Endothelial cells; Endothelial Cells - metabolism; Endothelium, Vascular - cytology; Endothelium, Vascular - metabolism; Epigenesis, Genetic; Epigenetics; Gene expression; Humans; Hybridization; Hypoxia; Ischemia; Kinases; MicroRNAs; MicroRNAs - genetics; MicroRNAs - metabolism; microRNA‐126; miRNA; Neovascularization, Physiologic; Original; Phosphatidylinositol 3-Kinases - genetics; Phosphatidylinositol 3-Kinases - metabolism; Scleroderma; Scleroderma, Systemic - genetics; Scleroderma, Systemic - metabolism; Scleroderma, Systemic - pathology; Vascular endothelial growth factor; Vascular Endothelial Growth Factor A - genetics; Vascular Endothelial Growth Factor A - metabolism; VEGF; Whole genome sequencing; Vermont; United States > US; endothelial cells; microRNA-126; VEGF; angiogenesis; epigenetics
• ISSN: 1582-1838; 1582-4934; 1582-4934
• DOI: 10.1111/jcmm.16727

Impaired angiogenesis in scleroderma (SSc) is a critical component of SSc pathology. MicroRNA‐126 (miR‐126) is expressed in endothelial cells (MVECs) where it regulates VEGF responses by repressing the negative regulators of VEGF, including the sprouty‐related protein‐1 (SPRED1), and phosphoinositide‐3 kinase regulatory subunit 2 (PIK3R2). MVECs were isolated from SSc skin and matched subjects (n = 6). MiR‐126 expression was measured by qPCR and in situ hybridization. Matrigel‐based tube assembly was used to test angiogenesis. MiR‐126 expression was inhibited by hsa‐miR‐126 inhibitor and enhanced by hsa‐miR‐126 Mimic. Epigenetic regulation of miR‐126 expression was examined by the addition of epigenetic inhibitors (Aza and TSA) to MVECs and by bisulphite genomic sequencing of DNA methylation of the miR‐126 promoter region. MiR‐126 expression, as well as EGFL7 (miR‐126 host gene), in SSc‐MVECs and skin, was significantly down‐regulated in association with increased expression of SPRED1 and PIK3R2 and diminished response to VEGF. Inhibition of miR‐126 in NL‐MVECs resulted in reduced angiogenic capacity, whereas overexpression of miR‐126 in SSc‐MVECs resulted in enhanced tube assembly. Addition of Aza and TSA normalized miR‐126 and EGFL7 expression levels in SSc‐MVECs. Heavy methylation in miR‐126/EGFL7 gene was noted. In conclusion, these results demonstrate that the down‐regulation of miR‐126 results in impaired VEGF responses.