We have recently demonstrated that serum CCL20 levels positively correlate with mean pulmonary arterial pressure in patients with systemic sclerosis (SSc). Considering a proangiogenic effect of CCL20 on endothelial cells via CCR6, the CCL20/CCR6 axis may contribute to the development of SSc vasculopathy. Therefore, we explored this hypothesis using clinical samples, cultured cells, and murine SSc models. The expression levels of CCL20 and CCR6 in the skin, mRNA levels of target genes, and the binding of transcription factor FLI1 to the target gene promoter were evaluated by immunostaining, quantitative reverse transcription PCR, and chromatin immunoprecipitation, respectively. Vascular permeability was evaluated by Evans blue dye injection in bleomycin-treated mice. Angiogenic activity of endothelial cells was assessed by in vitro angiogenesis assay. CCL20 expression was significantly elevated in dermal fibroblasts of patients with early diffuse cutaneous SSc, while CCR6 was significantly up-regulated in dermal small vessels of SSc patients irrespective of disease subtypes and disease duration. In human dermal microvascular endothelial cells, FLI1 siRNA induced the expression of CCR6, but not CCL20, and FLI1 bound to the CCR6 promoter. Importantly, vascular permeability, a representative SSc-like vascular feature of bleomycin-treated mice, was attenuated by Ccr6 siRNA treatment, and CCR6 siRNA suppressed the angiogenic activity of human dermal microvascular endothelial cells assayed by in vitro tube formation. The increased expression of endothelial CCR6 due to FLI1 deficiency may contribute to the development of SSc vasculopathy.

中文翻译：

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FLI1 缺乏导致的内皮 CCR6 表达导致与系统性硬化症相关的血管病变

我们最近证明，血清 CCL20 水平与系统性硬化症 (SSc) 患者的平均肺动脉压呈正相关。考虑到 CCL20 通过 CCR6 对内皮细胞的促血管生成作用，CCL20/CCR6 轴可能有助于 SSc 血管病变的发展。因此，我们使用临床样本、培养细胞和鼠 SSc 模型探索了这一假设。分别通过免疫染色、定量逆转录PCR和染色质免疫沉淀评估皮肤中CCL20和CCR6的表达水平、靶基因的mRNA水平以及转录因子FLI1与靶基因启动子的结合。通过在博来霉素处理的小鼠中注射伊文思蓝染料来评估血管通透性。通过体外血管生成试验评估内皮细胞的血管生成活性。CCL20 在早期弥漫性皮肤 SSc 患者的真皮成纤维细胞中表达显着升高，而 CCR6 在 SSc 患者的真皮小血管中显着上调，与疾病亚型和病程无关。在人真皮微血管内皮细胞中，FLI1 siRNA 诱导 CCR6 的表达，但不诱导 CCL20 的表达，并且 FLI1 与 CCR6 启动子结合。重要的是，血管通透性是博莱霉素处理小鼠的代表性 SSc 样血管特征，通过 Ccr6 siRNA 处理减弱，并且 CCR6 siRNA 抑制了通过体外管形成测定的人真皮微血管内皮细胞的血管生成活性。