Open AccessInhibition of USP4 attenuates pathological scarring by downregulation of the TGF‑β/Smad signaling pathway
Author(s) -
Jie Zhang,
Sijia Na,
Shuting Pan,
Sang Long,
Xin Yong,
Qingkun Jiang,
Zhongwei Lai,
Yan Ji,
Zhongyi Cao
Publication year - 2019
Publication title -
molecular medicine reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.727
H-Index - 56
eISSN - 1791-3004
pISSN - 1791-2997
DOI - 10.3892/mmr.2019.10370
Subject(s) - viability assay , western blot , smad , mtt assay , downregulation and upregulation , gene silencing , reverse transcription polymerase chain reaction , microbiology and biotechnology , cell growth , cell cycle , proliferating cell nuclear antigen , cell , signal transduction , pathology , biology , medicine , immunohistochemistry , messenger rna , biochemistry , gene
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.