Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University, Newcastle Upon Tyne, UK.
Department of Biosciences, Durham University, Durham, UK.
Exp Dermatol. 2021 Jan;30(1):162-168. doi: 10.1111/exd.14136. Epub 2020 Sep 10.
Systemic sclerosis is an autoimmune skin disease which is associated with inflammation and resulting skin fibrosis. Myofibroblasts are the key cell type associated with the fibrosis but how they are differentiated is not clear. DKK-1 is a Wnt antagonist that blocks Wnt-mediated fibrosis and is reduced in fibrotic conditions. Thus, DKK-1 is a clear negative regulator of fibrosis in systemic sclerosis and its regulation is unknown. The aim of this work is to determine the levels of DKK-1 in serum and tissues of SSc and its regulation.
Skin biopsies were taken from early diffuse systemic sclerosis patients and healthy controls and DKK-1 measured by ELISA; serum was also isolated and DKK-1 quantified. DKK-1 was also measured by qRT-PCR. MicroRNA33a-3p was measured by TaqMan PCR. miR mimics and controls were transfected into dermal fibroblasts. Bleomycin mouse model was employed and compared to vehicle control treated mice, and gene expression was employed for DKK-1 and various extracellular matrix genes.
DKK-1 is reduced in SSc skin and fibroblasts but is not reduced in the circulation in patients. MicroRNA33a-3p regulates DKK-1 levels epigenetically and is significantly reduced in SSc cells and whole tissue. DKK-1 is also reduced in the bleomycin mouse model and pro-fibrotic genes elevated.
DKK-1 is reduced in SSc cells and is regulated by miR33a-3p, and restoring DKK-1 levels through epigenetic means could be a therapeutic target in systemic sclerosis.
系统性硬化症是一种自身免疫性皮肤病，与炎症和由此导致的皮肤纤维化有关。成肌纤维细胞是与纤维化相关的关键细胞类型，但它们如何分化尚不清楚。DKK-1 是一种 Wnt 拮抗剂，可阻断 Wnt 介导的纤维化，并在纤维化条件下减少。因此，DKK-1 是系统性硬化症中纤维化的明确负调节剂，其调节尚不清楚。这项工作的目的是确定 SSc 血清和组织中 DKK-1 的水平及其调节。
从早期弥漫性系统性硬化症患者和健康对照者中采集皮肤活检，并通过 ELISA 测量 DKK-1；还分离血清并定量 DKK-1。通过 qRT-PCR 也测量了 DKK-1。通过 TaqMan PCR 测量了 microRNA33a-3p。将 miR 模拟物和对照物转染到真皮成纤维细胞中。采用博来霉素小鼠模型，并与接受载体对照治疗的小鼠进行比较，采用基因表达法检测 DKK-1 和各种细胞外基质基因。
DKK-1 在 SSc 皮肤和成纤维细胞中减少，但在患者循环中不减少。microRNA33a-3p 对 DKK-1 水平进行表观遗传调控，在 SSc 细胞和整个组织中明显减少。博来霉素小鼠模型中 DKK-1 减少，促纤维化基因升高。
DKK-1 在 SSc 细胞中减少，并受 miR33a-3p 调节，通过表观遗传手段恢复 DKK-1 水平可能成为系统性硬化症的治疗靶点。
