Research progress of relevant signals and mechanisms in clearance of apopto-sis cells / 中国免疫学杂志

Our bodies produce a lot of apoptotic cells every day,and the timely removal of these apoptotic cells is essential to maintain the immune balance of the body. In the removal of apoptotic cells,macrophages play a major role,and their removal process is divided into three stages:recruitment,identification and phagocytosis. In the recruitment stage,apoptotic cells secrete′find me′signals, and phagocytes respond and are recruited to apoptotic cells. At the identification stage, the ′eat-me′ signal of apoptotic cells was identified with the phagocytic receptor on the surface of phagocytes. Phagocytic phase, the ′eat-me′ signal transmits signals to macrophages,such as activating the small GTPase Rac1,which leads to actin polymerization and cytoskeleton rearrangement to promote the phagocytosis of apoptotic cells. If the removal mechanism of apoptotic cells is obstructive,the apoptotic cells that have not been cleared in time will enter the secondary necrotic state and release the self-antigens. These self-antigens may stimulate the body′s immune system to produce autoantibodies,leading to autoimmune diseases such as SLE. The research progress of the macrophage on the removal mechanism of apoptosis cells is reviewed in this paper.

Programmed cell death 5 correlates with disease activity and interleukin-17 in serum and synovial fluid of rheumatoid arthritis patients / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Programmed cell death 5 (PDCD5) is a novel apoptotic regulatory gene that promotes apoptosis in various tumor cells. Studies have shown that PDCD5 accelerates the apoptosis of synoviocytes in vitro, implying a potential role in rheumatoid arthritis (RA) pathogenesis. This study examined the expression of PDCD5 in serum and synovial fluid of RA patients, its effect on the expression of inflammatory cytokine, interleukin-17 (IL-17), and the assessment of disease activity in RA.</p><p><b>METHODS</b>PDCD5 and IL-17 levels in serum and synovial fluid from 18 patients with RA and 22 patients with osteoarthritis (OA) were detected using enzyme-linked immunosorbent assay (ELISA). Concentrations of serum PDCD5 in 40 healthy people were also detected as controls. As disease activity indices, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), rheumatoid factor (RF), and X-ray grading scale were also evaluated.</p><p><b>RESULTS</b>Serum and synovial fluid PDCD5 levels in RA patients were significantly higher than those in OA and healthy controls. Serum PDCD5 level was inversely correlated to CRP and ESR, and was significantly higher in the RF negative group than in the positive group. PDCD5 level was also negatively correlated with IL-17 levels both in serum and synovial fluid of RA patients. However, differences in synovial fluid PDCD5 level from RA patients at different Larsen stages were not detectable.</p><p><b>CONCLUSIONS</b>PDCD5 affects RA pathogenesis. Insufficient apoptosis of fibroblast-like synoviocytes and inflammatory cells in RA could increase the expression of PDCD5 protein. As PDCD5 levels correlated negatively with disease activity indices and IL-17 level, PDCD5 could become a target in the diagnosis and treatment of RA.</p>