Regulatory effects of electronic beam irradiation on mir-21/smad7-mediated collagen I synthesis in keloid-derived fibroblasts

Abstract

Keloid scarring is an abnormal pathological scar characterized by excessive fibro proliferation and extracellular matrix deposition. Electronic beam irradiation is commonly used with surgical removal to control high recurrence rates of keloid scarring; however, the mechanism remains unknown. In this study, we used keloid-derived primary fibroblasts (KF) as the cell model, and a dose of 15 Gy energy, followed by quantitative PCR (qPCR), western blotting and gene overexpression/knock down techniques were used to reveal the molecular mechanisms affected by electronic beam irradiation. We found that mir-21 was highly expressed in KF and was downregulated by irradiation. We also showed that smad7 was a direct target of mir-21. Moreover, the expression level of smad7 was low in KF and upregulated by irradiation. We also found that smad7 controls Col-1 synthesis by mediating p38 phosphorylation, and this process was affected by electronic beam irradiation. The regulatory effect of electronic beam irradiation on the expression of mir-21, smad7, p38, p-p38 and Col-1 could be partly restored by mir-21 overexpression achieved by mir-21 mimic transfection. In conclusion, our data demonstrated that mir-21/smad7 regulated Col-1 expression in KF and that electronic beam irradiation was capable of decreasing Col-1 production by modifying mir-21/smad7-mediated p38 activation. This is the first report identifying the effects of electronic beam irradiation on miRNAs, providing a novel strategy to discover the molecular mechanisms of radiotherapy.

Combined surgical excision and electron external beam radiation improves the treatment of keloids: A descriptive study

“…In addition, intralesional excisions further help to reduce the local tension, which is a controversial topic 16 . We applied intralesional excisions since surgical excision debulks the most active part of keloids and the adjuvant radiotherapy, which has been proven to suppress keloid fibroblast proliferation and collagen synthesis 17‐19 . Thus, to minimize the local tension of keloids, we adopted the technique of layered sutures using local flaps and intralesional excisions.…”

MnTE-2-PyP Treatment, or NOX4 Inhibition, Protects against Radiation-Induced Damage in Mouse Primary Prostate Fibroblasts by Inhibiting the TGF-Beta 1 Signaling Pathway

“…miRNA21, which is an important regulator of fibrosis, can inhibit Smad7 protein translation without altering its mRNA level (63–65). Upregulation of miRNA21 expression has been reported in fibrosis (66, 67). miRNA21 binds to the 3′UTR of Smad7 mRNA and inhibits its translation rather than degrading the mRNA (68).…”

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

“…In addition to these results, Tgf-β , Mmp-2 , Col-Ia , and Col-IVa were significantly increased in the GV compared to CV at day 7 ( Tgf-β1 GV, 4.45 ± 0.45; CV, 1.13 ± 0.41; average increase, 393%; p < 0.001; Figure 2 E; Col-Ia day 3 GV, 5.31 ± 0.56; CV, 1.07 ± 0.27; average increase, 495%; p = 0.0008; day 7 GV, 4.09 ± 0.23; CV, 1.016 ± 0.13; average increase, 402%; p = 0.0016; Figure 2 F; Col-IVa day 7 GV, 41.61 ± 0.016; CV, 0.85 ± 0.12; average increase, 190%; p = 0.022; Figure 2 G; and Mmp-2 GV, 3.48 ± 0.38; CV, 1.04 ± 0.19; average increase, 334.7%; p < 0.001; Figure S5 D). We speculate that the increase in TGF-β1 may occur due to the downregulation of SMAD7 by miR-21, 12 leading to the upregulation of Col-Ia at day 3.…”