Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, 639 Zhizaoju Road, Shanghai, 200011, P. R. China.
BMC Genomics. 2021 Aug 12;22(1):613. doi: 10.1186/s12864-021-07920-8.
Hypertrophic scar (HTS) is a fibroproliferative skin disorder characterized by excessive cell proliferation, migration, and extracellular matrix (ECM) deposition. The CUB and Sushi multiple domains 1 (CSMD1) has previously been identified as the key regulatory gene of hypertrophic scar by a large sample GWAS study. However, further research has not yet been conducted to verify this finding in other HTS patients and to determine the underlying mechanism.
In this study, we verified that CSMD1 was downregulated in both HTS tissue and HTS-derived fibroblasts. The knockdown of CSMD1 resulted in enhanced migration and fibronectin1 (FN1) secretion in fibroblasts in vitro. In addition, the upstream and downstream regulatory mechanisms of CSMD1 were also investigated through microRNA (miRNA) databases screening and RNA-sequencing (RNA-seq) respectively. The screening of four common microRNA (miRNA) databases suggested that miR-190a-3p binds to the CSMD1 and may regulate its expression. We confirmed that miR-190a-3p directly targeted the CSMD1-3'-UTR using luciferase reporter assays. Furthermore, the overexpression of miR-190a-3p showed promotion of migratory activity and FN1 secretion in fibroblasts, resembling the effect of CSMD1 knockdown; whereas the knockdown of miR-190a-3p exerted the opposite effect. Finally, transcriptomic analysis showed activation of Janus kinase-signal transducer and activator of transcription (JAK/STAT) signaling pathway in the CSMD1 knockdown fibroblasts.
This study has validated the conclusions of the previous GWAS study conducted in Chinese population. In vitro experiments have provided further evidence on the function of CSMD1 in the development of HTS, and have also revealed the underlying upstream and downstream regulating mechanisms. Additionally, the JAK/STAT signaling pathway identified using RNA-seq might provide a potential treatment approach, especially for HTS.
增生性瘢痕（HTS）是一种以过度细胞增殖、迁移和细胞外基质（ECM）沉积为特征的纤维增生性皮肤疾病。先前的一项大样本 GWAS 研究表明，CUB 和 Sushi 多结构域 1（CSMD1）是增生性瘢痕的关键调节基因。然而，尚未进行进一步的研究来验证这一发现是否适用于其他 HTS 患者，并确定其潜在机制。
本研究验证了 CSMD1 在 HTS 组织和 HTS 衍生的成纤维细胞中均下调。CSMD1 的敲低导致成纤维细胞体外迁移和纤连蛋白 1（FN1）分泌增强。此外，还通过 microRNA（miRNA）数据库筛选和 RNA 测序（RNA-seq）分别研究了 CSMD1 的上下游调控机制。四个常见 miRNA 数据库的筛选表明，miR-190a-3p 与 CSMD1 结合并可能调节其表达。我们通过荧光素酶报告基因检测证实 miR-190a-3p 可直接靶向 CSMD1-3'-UTR。此外，miR-190a-3p 的过表达表现出促进成纤维细胞迁移活性和 FN1 分泌的作用，类似于 CSMD1 敲低的作用；而 miR-190a-3p 的敲低则产生相反的效果。最后，转录组分析显示 CSMD1 敲低的成纤维细胞中 Janus 激酶-信号转导和转录激活因子（JAK/STAT）信号通路被激活。
本研究验证了先前在中国人群中进行的 GWAS 研究的结论。体外实验进一步提供了 CSMD1 在 HTS 发展中的功能证据，并揭示了其潜在的上游和下游调节机制。此外，RNA-seq 鉴定的 JAK/STAT 信号通路可能为 HTS 的治疗提供一种潜在的方法。
