1.Anti-endotoxic effects of syringic acid in Radix Isatidis
Yunhai LIU ; Jiangguo FANG ; Xuepeng GONG ; Wei XIE ;
Chinese Traditional and Herbal Drugs 1994;0(10):-
Object To study the anti endotoxic effect of syringic acid (SA) which was isolated from Radix Isatidis (Banlangen in Chinese, BLG). Methods SA was extracted and isolated from BLG and made to 1% solution. The content of SA pretreated ET was quantitatively determined using Limulus Test. Then the ability of fever induction of endotoxin (ET) pretreated with SA was measured using endotoxin induced fever test in rabbits. At last, the lipopolysaccharide (LPS) induced death in mice pretreated with and without SA was compared. Results Being pretreated with SA, 83.16% ET was destroyed, the ET induced fever in rabbits relieved markedly and the LPS induced death rate in mice dropped from 68% to 20%. Conclusion SA isolated from BLG has anti endotoxic effects.
2.Force-dependent calcium signaling and its pathway of human neutrophils on P-selectin in flow.
Bing HUANG ; Yingchen LING ; Jiangguo LIN ; Xin DU ; Ying FANG ; Jianhua WU
Protein & Cell 2017;8(2):103-113
P-selectin engagement of P-selectin glycoprotein ligand-1 (PSGL-1) causes circulating leukocytes to roll on and adhere to the vascular surface, and mediates intracellular calcium flux, a key but unclear event for subsequent arresting firmly at and migrating into the infection or injured tissue. Using a parallel plate flow chamber technique and intracellular calcium ion detector (Fluo-4 AM), the intracellular calcium flux of firmly adhered neutrophils on immobilized P-selectin in the absence of chemokines at various wall shear stresses was investigated here in real time by fluorescence microscopy. The results demonstrated that P-selectin engagement of PSGL-1 induced the intracellular calcium flux of firmly adhered neutrophils in flow, increasing P-selectin concentration enhanced cellular calcium signaling, and, force triggered, enhanced and quickened the cytoplasmic calcium bursting of neutrophils on immobilized P-selectin. This P-selectin-induced calcium signaling should come from intracellular calcium release rather than extracellular calcium influx, and be along the mechano-chemical signal pathway involving the cytoskeleton, moesin and Spleen tyrosine kinase (Syk). These results provide a novel insight into the mechano-chemical regulation mechanism for P-selectin-induced calcium signaling of neutrophils in flow.
Calcium Signaling
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Female
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Humans
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Male
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Membrane Glycoproteins
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metabolism
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Neutrophils
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metabolism
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P-Selectin
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metabolism
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Stress, Mechanical
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Syk Kinase
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metabolism
3.LPS stimulating neutrophils firmly adhered to ICAM-1 to form extracellular traps depends on integrin Mac-1 and cytoskeletal proteins.
Tiantian HONG ; Wang LIU ; Jiaqi HUANG ; Baisong ZHAO ; Ying FANG ; Jianhua WU ; Jiangguo LIN
Journal of Biomedical Engineering 2021;38(5):903-910
Neutrophil extracellular traps (NETs) play an important role in the formation of immunothrombosis. However, how vascular endothelial cells mediate the formation of NETs has not been fully understood. We stimulated neutrophils firmly attached on the endothelial cell surface intercellular adhesion molecule-1 (ICAM-1) with lipopolysaccharide (LPS) or phorbol-12-myristate-13-acetate (PMA) for 4 h, then labeled NETs-DNA with Sytox green dye and the formation of NETs was observed by fluorescent microscopy. The area and fluorescence intensity of NETs-DNA were analyzed to quantify the formation of NETs. The results showed that both PMA and LPS were able to induce firmly adhered neutrophils on ICAM-1 to produce NETs. NETs induced by PMA were independent of neither β2 integrin lymphocyte function-associated antigen-1 (LFA-1) nor macrophage antigen complex-1 (Mac-1). In contrast, LPS-stimulated NETs were mediated by Mac-1 integrin, but not by LFA-1. After inhibition of actin filaments or Talin-1, the formation of NETs irrespective of the stimulus was significantly reduced. This study reveals the mechanism of the direct interaction between neutrophils and endothelial cells to produce NETs under inflammatory conditions, providing a new theoretical basis for the treatment of related diseases and the development of new drugs.
Cytoskeletal Proteins
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Endothelial Cells
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Extracellular Traps
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Integrins
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Intercellular Adhesion Molecule-1
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Lipopolysaccharides/pharmacology*
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Macrophages
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Neutrophils
4.The characteristics of neutrophil extracellular traps produced by all-trans retinoic acid-induced dHL-60 under PMA stimulation.
Wang LIU ; Jinhua FANG ; Tiantian HONG ; Jiaqi HUANG ; Baisong ZHAO ; Ying FANG ; Jianhua WU ; Jiangguo LIN
Journal of Biomedical Engineering 2022;39(5):909-918
Extracellular traps released by neutrophils (neutrophil extracellular traps, NETs) are a double-edged sword, and understanding the mechanism of NET formation is of great significance for disease treatment. However, the short lifespan, the large individual differences, and the inability to perform gene editing render it difficult to decipher NET formation using neutrophils. It is necessary to find a model cell to replace neutrophils to study the mechanism of NET formation. In this study, we used different concentrations (0, 0.1, 1, and 10 μmol/L) of all-trans retinoic acid (ATRA) to differentiate HL-60 cells for different days (1, 3, 5, and 7 days). By detecting the cell viability and nuclear morphology of cells, we confirmed that HL-60 cells were differentiated to neutrophil-like cells (dHL-60) after treated with ATRA for at least 5 days. Using immunofluorescence staining to detect the formation of NETs, we demonstrated that dHL-60 cells differentiated for 5 days with 1 μmol/L ATRA could generate NETs comparable to those produced by neutrophils upon phorbol 12-myristate 13-acetate (PMA) stimulation, without histone H3 citrullination. Furthermore, the formation of NETs by dHL-60 cells were NADPH-dependent and PAD4-independent, consistent with neutrophils. Taken together, these observations suggest that dHL-60 cells differentiated with 1 μmol/L ATRA for 5 days can be used as a model cell for neutrophils to study the mechanism of NET formation.
Humans
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Extracellular Traps
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Tetradecanoylphorbol Acetate/pharmacology*
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Neutrophils
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HL-60 Cells
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Tretinoin/pharmacology*