Department of Rheumatology, Xiangya Hospital, Central South University, 87 Xiangya Road, Changsha, Hunan, 410008, People's Republic of China.
Department of Pathophysiology, Xiangya School of Medicine, Central South University, 110 Xiangya Road, Changsha, Hunan, 410008, People's Republic of China.
Arthritis Res Ther. 2018 Jul 5;20(1):134. doi: 10.1186/s13075-018-1632-x.
Dermatomyositis and polymyositis are the best known idiopathic inflammatory myopathies (IIMs). Classic histopathologic findings include the infiltration of inflammatory cells into muscle tissues. Neutrophil serine proteinases (NSPs) are granule-associated enzymes and play roles in inflammatory cell migration by increasing the permeability of vascular endothelial cells. In this study, we aimed to find the roles of NSPs in pathogenesis of IIMs.
RNA and DNA were isolated to measure the relative expression of NSPs and their methylation levels. The expression of NSPs in serum and muscle tissues was tested by enzyme-linked immunosorbent assay, immunohistochemistry, and immunofluorescence, respectively. Serum from patients was used to culture the human dermal microvascular endothelial cells (HDMECs), and then we observed the influence of serum on expression of VE-cadherin, endothelial cell tube formation, and transendothelial migration of peripheral blood mononuclear cells (PBMCs).
We found that the expression of NSPs was increased in PBMCs, serum, and muscle tissues of IIM patients; these NSPs were hypomethylated in the PBMCs of patients. Serum NSPs were positively correlated with clinical indicators of IIM patients, including lactic dehydrogenase, erythrocyte sedimentation rate, C-reactive protein, immunoglobulin G, immunoglobulin M, and immunoglobulin A. Patients with anti-Jo-1, with anti-Ro-52, or without interstitial lung disease had lower levels of proteinase 3. Serum NSPs degraded the VE-cadherin of HDMECs, and serum NSP application increased the permeability of HDMECs.
Our studies indicate, for the first time, that NSPs play an important role in muscle inflammatory cell infiltration by increasing the permeability of vascular endothelial cells in IIM patients.
皮肌炎和多发性肌炎是最著名的特发性炎性肌病（IIM）。经典的组织病理学发现包括炎症细胞浸润到肌肉组织中。中性粒细胞丝氨酸蛋白酶（NSPs）是颗粒相关酶，通过增加血管内皮细胞的通透性在炎症细胞迁移中发挥作用。在这项研究中，我们旨在寻找 NSPs 在 IIM 发病机制中的作用。
分离 RNA 和 DNA 以测量 NSPs 的相对表达及其甲基化水平。通过酶联免疫吸附试验、免疫组织化学和免疫荧光分别检测血清和肌肉组织中 NSPs 的表达。使用患者的血清培养人真皮微血管内皮细胞（HDMEC），然后观察血清对 VE-钙黏蛋白表达、内皮细胞管形成和外周血单核细胞（PBMC）跨内皮迁移的影响。
我们发现 NSPs 在 IIM 患者的 PBMCs、血清和肌肉组织中表达增加；这些 NSPs 在患者的 PBMCs 中低甲基化。血清 NSPs 与 IIM 患者的临床指标呈正相关，包括乳酸脱氢酶、红细胞沉降率、C 反应蛋白、免疫球蛋白 G、免疫球蛋白 M 和免疫球蛋白 A。抗 Jo-1 阳性、抗 Ro-52 阳性或无间质性肺病的患者蛋白酶 3 水平较低。血清 NSPs 降解 HDMEC 的 VE-钙黏蛋白，并且血清 NSP 的应用增加了 HDMEC 的通透性。
我们的研究首次表明，NSPs 通过增加 IIM 患者血管内皮细胞的通透性，在肌肉炎症细胞浸润中发挥重要作用。
