Ruixue Duo, Xiaoyuan Wang, Rong Zhu, Yan Zhang, Juan Zhang, Haili Shen#
Department of Rheumatology, The Second Hospital of Lanzhou University, Lan zhou, 730030, Gan su Province, China
Objective: The objective was to assess rheumatoid arthritis (RA) macrophage immunological synapse (IS) formation and as well the capacity of the IS to protect macrophages from apoptosis. Moreover, the effect of cyclosporin A (CsA) and its ligand, cyclophilin A (CypA), on IS formation was assessed with regard to the control of macrophage apoptosis.
Methods: Peripheral blood was collected from ten healthy controls and ten confirmed active RA patients. CD14+ macrophages were co-cultured with activated CD4+ T cells to promote IS formation. The macrophage–T cell conjugates were cultured for 16 h to induce apoptosis, which was analyzed by Annexin V-PI staining, TUNEL assay, and DAPI staining. CypA (200 ng/ml) or CsA (1 μg/ml) were assessed for their effect on IS formation and apoptosis of IS macrophages. Statistical analysis was by Student’s t-test.
Results: More ISs were formed by cells from RA patients than from healthy controls. Annexin V-PI staining, TUNEL assay, and DAPI staining demonstrated apoptosis to be less in macrophages that formed ISs with CD4+ T cells. This effect was more pronounced for RA cells than for healthy control cells. For RA cells, CypA further reduced the rate of apoptosis, while CsA had the opposite effect.
Conclusion: For RA patients, macrophages participated in the formation of ISs and that participation significantly reduced macrophage apoptosis.CypA enhanced the effect but CsA suppressed it. These results provide for a new theoretical and therapeutic foundation upon which to understand the prolonged survival and function of RA macrophages. Such macrophages may enhance inflammation and increase joint destruction in RA.
Immunological synapse, Macrophage, Apoptosis, Rheumatoid arthritis, Cyclophilin A, Cyclosporin.