Department of Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
Dr. Nasser Al-Rashid Research Chair in Ophthalmology, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
Clin Exp Ophthalmol. 2022 Aug;50(6):632-652. doi: 10.1111/ceo.14077. Epub 2022 Apr 12.
Furin converts inactive proproteins into bioactive forms. By activating proinflammatory and proangiogenic factors, furin might play a role in pathophysiology of proliferative diabetic retinopathy (PDR).
We studied vitreous samples from PDR and nondiabetic patients, epiretinal membranes from PDR patients, retinal microvascular endothelial cells (HRMECs), retinal Müller cells and rat retinas by ELISA, Western blot analysis, immunohistochemistry and immunofluorescence microscopy. We performed in vitro angiogenesis assays and assessed adherence of monocytes to HRMECs.
Furin levels were significantly increased in PDR vitreous samples. In epiretinal membranes, immunohistochemistry analysis revealed furin expression in monocytes/macrophages, vascular endothelial cells and myofibroblasts. Furin was significantly upregulated in diabetic rat retinas. Hypoxia and TNF-α induced significant upregulation of furin in Müller cells and HRMECs. Furin induced upregulation of phospho-ERK1/2, p65 subunit of NF-κB, ADAM17 and MCP-1 in cultured Müller cells and phospho-ERK1/2 in cultured HRMECs and induced HRMECs migration. Treatment of monocytes with furin significantly increased their adhesion to HRMECs. Intravitreal administration of furin in normal rats induced significant upregulation of p65 subunit of NF-κB, phospho-ERK1/2 and ICAM-1 in the retina. Inhibition of furin with dec-CMK significantly decreased levels of MCP-1 in culture medium of Müller cells and HRMECs and significantly attenuated TNF-α-induced upregulation of p65 subunit of NF-κB, ICAM-1 and VCAM-1 in HRMECs. Dec-CMK significantly decreased adherence of monocytes to HRMECs and TNF-α-induced upregulation of adherence of monocytes to HRMECs. Treatment of HRMECs with dec-CMK significantly attenuated migration of HRMECs.
Furin is a potential driver molecule of PDR-associated inflammation and angiogenesis.
弗林蛋白酶可将无活性的前蛋白转化为生物活性形式。弗林蛋白酶通过激活前炎症和促血管生成因子，可能在增生性糖尿病视网膜病变（PDR）的病理生理学中发挥作用。
我们通过 ELISA、Western blot 分析、免疫组织化学和免疫荧光显微镜研究了 PDR 和非糖尿病患者的玻璃体样本、PDR 患者的视网膜内细胞外膜、视网膜微血管内皮细胞（HRMEC）、视网膜 Müller 细胞和大鼠视网膜。我们进行了体外血管生成试验，并评估了单核细胞与 HRMEC 的黏附作用。
PDR 玻璃体样本中弗林蛋白酶水平显著升高。在视网膜内细胞外膜中，免疫组织化学分析显示弗林蛋白酶在单核细胞/巨噬细胞、血管内皮细胞和肌成纤维细胞中表达。糖尿病大鼠视网膜中弗林蛋白酶显著上调。缺氧和 TNF-α诱导 Müller 细胞和 HRMEC 中弗林蛋白酶的显著上调。弗林蛋白酶诱导培养的 Müller 细胞中磷酸化 ERK1/2、NF-κB 的 p65 亚单位、ADAM17 和 MCP-1 的上调以及培养的 HRMEC 中磷酸化 ERK1/2 的上调，并诱导 HRMEC 迁移。用弗林蛋白酶处理单核细胞可显著增加其与 HRMEC 的黏附。在正常大鼠玻璃体腔注射弗林蛋白酶可显著上调视网膜中 NF-κB 的 p65 亚单位、磷酸化 ERK1/2 和 ICAM-1。用 dec-CMK 抑制弗林蛋白酶可显著降低 Müller 细胞和 HRMEC 培养基中的 MCP-1 水平，并显著减弱 TNF-α诱导的 HRMEC 中 NF-κB 的 p65 亚单位、ICAM-1 和 VCAM-1 的上调。dec-CMK 显著降低单核细胞与 HRMEC 的黏附以及 TNF-α诱导的单核细胞与 HRMEC 的黏附上调。用 dec-CMK 处理 HRMEC 可显著减弱 HRMEC 的迁移。
弗林蛋白酶是 PDR 相关炎症和血管生成的潜在驱动分子。
