Department of Internal Medicine and Medical Specialties, Rheumatology, Sapienza University of Rome, Rome, Italy.
Arthritis Res Ther. 2019 Nov 21;21(1):245. doi: 10.1186/s13075-019-2015-7.
Circulating endothelial progenitor cells (EPCs) are biologic markers of endothelial function. In patients with systemic lupus erythematosus (SLE), the numerical reduction and functional impairment of EPCs contribute to the endothelial dysfunction. Through ex vivo and in vitro studies, we aimed at evaluating the effects of B lymphocyte stimulator (BLyS) on EPC colonies and endothelial cells and also investigating BLyS receptor expression on these cells.
EPCs were isolated from peripheral blood mononuclear cells (PBMC). In order to evaluate their ability to form colonies, EPCs were cultured on fibronectin-coated dishes and incubated with BlyS alone or BlyS and belimumab. Apoptosis of EPCs and endothelial cell line EA.hy926 was evaluated after 6, 12, and 24 h of incubation with BLyS and after 6 h with BLyS and belimumab. The expression of B cell activating factor-receptor (BAFF-R), B cell maturation antigen (BCMA), and transmembrane activator and calcium modulator and cyclophilin ligand (CAML) interactor (TACI) on EPCs and EA.hy926 was analyzed by cytofluorimetry.
The number of EPC colonies was lower in patients than in controls. Moreover, the colonies from SLE patients were poorly organized compared to controls; the addition of belimumab restored the colony structure. Incubation with BLyS induced apoptosis of EPCs and EA.hy926 that was inhibited by the co-incubation with belimumab. BAFF-R and BCMA were expressed on both EPCs and EA.hy926, while TACI was expressed only on EPCs.
EPCs and endothelial cells preferentially express BAFF-R which could be involved in the pro-apoptotic effect of BlyS. Belimumab administration seems to restore the quantitative and qualitative changes of EPC colonies both ex vivo and in vitro.
循环内皮祖细胞（EPC）是内皮功能的生物学标志物。在系统性红斑狼疮（SLE）患者中，EPC 的数量减少和功能受损导致内皮功能障碍。通过体外和体内研究，我们旨在评估 B 淋巴细胞刺激因子（BLyS）对 EPC 集落和内皮细胞的影响，并研究这些细胞上 BLyS 受体的表达。
从外周血单核细胞（PBMC）中分离 EPC。为了评估它们形成集落的能力，将 EPC 培养在纤维连接蛋白包被的培养皿上，并单独或与 BlyS 和贝利单抗一起孵育。用 BLyS 孵育 6、12 和 24 小时后，评估 EPC 和内皮细胞系 EA.hy926 的凋亡情况，并用 BLyS 和贝利单抗孵育 6 小时后评估凋亡情况。通过流式细胞术分析 EPC 和 EA.hy926 上 B 细胞激活因子受体（BAFF-R）、B 细胞成熟抗原（BCMA）和跨膜激活剂和钙调环磷酸醇配体相互作用蛋白（TACI）的表达。
患者的 EPC 集落数量低于对照组。此外，与对照组相比，SLE 患者的集落结构较差；贝利单抗的加入恢复了集落结构。BLyS 的孵育诱导 EPC 和 EA.hy926 的凋亡，这种凋亡可被贝利单抗共孵育所抑制。BAFF-R 和 BCMA 均表达于 EPC 和 EA.hy926，而 TACI 仅表达于 EPC。
EPC 和内皮细胞优先表达 BAFF-R，这可能参与了 BlyS 的促凋亡作用。贝利单抗的给药似乎在体外和体内都恢复了 EPC 集落的数量和质量变化。
