Inhibition of USP4 attenuates pathological scarring by downregulation of the TGF‑β/Smad signaling pathway

• Published in: Molecular medicine reports Vol. 20; no. 2; pp. 1429 - 1435
• Main Authors: Zhang, Jie, Na, Sijia, Pan, Shuting, Long, Sang, Xin, Yuqi, Jiang, Qingkun, Lai, Zhongwei, Yan, Junfeng, Cao, Zhongyi
• Format: Journal Article
• Language: English
• Published: Greece Spandidos Publications UK Ltd 01.08.2019
• Subjects: Animals; Annealing; Biotechnology; Cell cycle; Cell Line, Tumor; Cell proliferation; Cell Proliferation - drug effects; Cell Survival - drug effects; Cell viability; Cicatrix - genetics; Cicatrix - metabolism; Cicatrix - pathology; Cicatrix - prevention & control; Experiments; Extracellular matrix; Fibroblasts; Fibroblasts - metabolism; Fibroblasts - pathology; Fibroblasts - transplantation; Gene Expression Regulation; Growth factors; Humans; Hypertrophy; Immunoprecipitation; Keloid - genetics; Keloid - metabolism; Keloid - pathology; Mice; Mice, Inbred BALB C; Mice, Nude; Polymerase chain reaction; Proteins; Receptor, Transforming Growth Factor-beta Type I - genetics; Receptor, Transforming Growth Factor-beta Type I - metabolism; Reverse transcription; Ribonucleic acid; RNA; RNA, Small Interfering - genetics; RNA, Small Interfering - metabolism; Scars; Signal Transduction; Smad protein; Smad7 protein; Smad7 Protein - genetics; Smad7 Protein - metabolism; Terphenyl Compounds - pharmacology; Transforming Growth Factor beta - genetics; Transforming Growth Factor beta - metabolism; Transplantation, Heterologous; Trauma; Ubiquitin; Ubiquitin-Specific Proteases - antagonists & inhibitors; Ubiquitin-Specific Proteases - genetics; Ubiquitin-Specific Proteases - metabolism; Ubiquitin-specific proteinase; Ubiquitination; Wound healing; Beijing China
• DOI: 10.3892/mmr.2019.10370
• ISSN: 1791-2997

Pathological scarring is a result of the hypertrophy of scar tissue during tissue repair following trauma. The aim of the present study was to assess the effect of ubiquitin‑specific protease 4 (USP4) silencing on pathological scarring, and to evaluate the mechanistic basis for the effect. An MTT assay was used to assess cell viability. Immunoprecipitation (IP) was used to determine ubiquitination levels of the TGF‑β receptor (TβR)I and Smad7. Tumor formation was assessed by injecting keloid fibroblasts. Hematoxylin and eosin staining was used to detect pathological changes in tumor tissue. Reverse transcription quantitative polymerase chain reaction and western blot analysis assays were used to evaluate the expression levels of TβRI and Smad7. Compared with the untreated control animals, cell viability and the expression of TβRI and Smad7 increased significantly in animals treated with TGF‑β. Short hairpin RNA for USP4 (shUSP4) decreased the cell viability of negative control cells, TGF‑β‑induced cellular proliferation, and the expression of TβRI and Smad7. IP experiments indicated that the ubiquitination level of TβRI was decreased following USP4 silencing. There was no remarkable difference in the structure of scar tissue among the various animal groups at 14 days following treatment, while the necrotic area of the scar tissue in the shUSP4 and vialinin A (USP inhibitor)‑treated animals increased significantly at the 28th and 42nd day compared with the control animals. At days 14, 28 and 42, the expression levels of TβRI and Smad7 in the shUSP4 and vialinin A‑treated animals were significantly decreased compared with the control animals (P<0.05). In summary, interference with or inhibition of USP4 prevented the activity of the TGF‑β/Smad pathway signaling and inhibited the formation of pathological scars.