McCoy Sara S, Reed Tamra J, Berthier Celine C, Tsou Pei-Suen, Liu Jianhua, Gudjonsson Johann E, Khanna Dinesh, Kahlenberg J Michelle
Department of Internal Medicine, Division of Rheumatology, University of Wisconsin, Madison, WI.
Department of Internal Medicine, Division of Rheumatology.
Rheumatology (Oxford). 2017 Nov 1;56(11):1970-1981. doi: 10.1093/rheumatology/kex280.
SSc is a devastating disease that results in fibrosis of the skin and other organs. Fibroblasts are a key driver of the fibrotic process through deposition of extracellular matrix. The mechanisms by which fibroblasts are induced to become pro-fibrotic remain unclear. Thus, we examined the ability of SSc keratinocytes to promote fibroblast activation and the source of this effect.
Keratinocytes were isolated from skin biopsies of 9 lcSSc, 10 dcSSc and 13 control patients. Conditioned media was saved from the cultures. Normal fresh primary fibroblasts were exposed to healthy control and SSc keratinocyte conditioned media in the presence or absence of neutralizing antibodies for TGF-β. Gene expression was assessed by microarrays and real-time PCR. Immunocytochemistry was performed for α-smooth muscle actin (α-SMA), collagen type 1 (COL1A1) and CCL5 expression.
SSc keratinocyte conditioned media promoted fibroblast activation, characterized by increased α-SMA and COL1A1 mRNA and protein expression. This effect was independent of TGF-β. Microarray analysis identified upregulation of nuclear factor κB (NF-κB) and downregulation of peroxisome proliferator-activated receptor γ (PPAR-γ) pathways in both SSc subtypes. Scleroderma keratinocytes exhibited increased expression of NF-κB-regulated cytokines and chemokines and lesional skin staining confirmed upregulation of CCL5 in basal keratinocytes.
Scleroderma keratinocytes promote the activation of fibroblasts in a TGF-β-independent manner and demonstrate an imbalance in NF-κB1 and PPAR-γ expression leading to increased cytokine and CCL5 production. Further study of keratinocyte mediators of fibrosis, including CCL5, may provide novel targets for skin fibrosis therapy.
系统性硬化症（SSc）是一种破坏性疾病，可导致皮肤和其他器官纤维化。成纤维细胞通过分泌细胞外基质，成为纤维化过程的关键驱动因素。成纤维细胞被诱导成为促纤维化细胞的机制尚不清楚。因此，我们研究了SSc角质形成细胞促进成纤维细胞活化的能力及其作用来源。
从9例局限性皮肤型SSc、10例弥漫性皮肤型SSc和13例对照患者的皮肤活检样本中分离角质形成细胞。收集细胞培养上清液。将正常新鲜原代成纤维细胞暴露于健康对照和SSc角质形成细胞条件培养基中，同时加入或不加入TGF-β中和抗体。通过微阵列和实时PCR评估基因表达。对α-平滑肌肌动蛋白（α-SMA）、I型胶原（COL1A1）和CCL5表达进行免疫细胞化学检测。
SSc角质形成细胞条件培养基促进了成纤维细胞的活化，表现为α-SMA和COL1A1 mRNA及蛋白表达增加。这种作用与TGF-β无关。微阵列分析发现，两种SSc亚型中核因子κB（NF-κB）上调，过氧化物酶体增殖物激活受体γ（PPAR-γ）信号通路下调。硬皮病角质形成细胞中NF-κB调节的细胞因子和趋化因子表达增加，病变皮肤染色证实基底角质形成细胞中CCL5上调。
硬皮病角质形成细胞以不依赖TGF-β的方式促进成纤维细胞活化，并表现出NF-κB1和PPAR-γ表达失衡，导致细胞因子和CCL5产生增加。进一步研究包括CCL5在内的角质形成细胞纤维化介质，可能为皮肤纤维化治疗提供新靶点。
