ABSTRACT
Thrombomodulin (TM) is a single-chain transmembrane glycoprotein that mainly exists in vascular endothelial cells, hematopoietic progenitor cells, monocytes and macrophages. TM is mainly composed of five structural regions: the N-terminal lectin-like domain which plays a role in anti-inflammatory, and the six epidermal growth factor-like repeats which function as coagulation and fibrinolysis as well as serine-rich threonine regions and transmembrane domains and cytoplasmic domains. TM exhibits anti-inflammatory and anticoagulant effects by binding to thrombin to activate protein C, and TM-thrombin complex can also activate fibrinolytic inhibitors to suppress fibrinolysis. Previous reports showed that inhibiting epithelial mesenchymal transformation, mitogen-activated protein kinase or activating protein C and fibrinolytic inhibitor are the major mechanisms by which TM exerts anti-tumor properties. In atherosclerosis, TM can prevent atherosclerosis by blocking the activation of thrombin-mediated PAR-1 and inhibiting autophagy and apoptosis of endothelial cells. TM lectin-like domains can also bind to thrombin to inhibit its activity and further inhibit pulmonary thrombosis, fibrosis and inflammation. Moreover, TM protein is also involved in the pathogenesis of diabetic nephropathy, preeclampsia and ischemia-reperfu-sion injury. At present, TM is only clinically used for the treatment of sepsis and disseminated intravascular coagulation. Its role and therapeutic potential in cardiovascular and cerebrovascular diseases, cancers and other diseases deserve further exploration.
ABSTRACT
Objective To explore the protective effect of atorvastatin on irradiated endothelium and the thrombomodulin(TM)expression.Methods Cultured human coronary artery endothelial cells(HCAEC)and human umbilical vein endothelial cells(HUVEC)were treated by atorvastatin at the final concentration of 10 μmol/ml for 10 min,and then irradiated with 2 and 25 Gy.Cell cycles status and TM expression were quantitatively measured by flow cytometry 24 hours after irradiation.Protein C activation in endothelial cells was also assessod.Results After administration with atorvastatin for 24 h,the TM expression increased by 77%,59% and 61% in normal control group,2 Gy group and 25 Gy group,respectively(t=27.395,26.420,58.065;P=0.000).The protein C levels decreased by 23% and 34% compared with the normal group post-irradiation to 2 and 25 Gy,but increased by 79% and 76% compared with the irradiated control group after administration with atorvastatin.The rates of cell apoptosis decreased by 6% and 16% in 2 Gy and 25 Gy groups,respectively after administration with atorvastatin for 24 h(t=4.178,17.863;P=0.000).Conclusions Atorva statin can protect endothelia cell from irradiation-induced apeptosis by increasing TM expression and protein C activation.
ABSTRACT
Objective To produce anti-thrombomodulin antibodies.Methods Using genetic immunization: Eukaryotic expression plasmid pcDNA3.1/TM(LEO),encoding all the extracellular domain of human thrombomodulin and signal peptides but lacking the transmembrance and cytoplasmic domains was constructed, which recombinant thrombomodulin was secreted soluble product. The plasmid was isolated from large-scale bacterial cultures by treatment with alkali and SDS, purified by precipitation with polyethylene Glycol (PEG). Recombinant plasmid was injected into tibial muscle of BALB/c mice. The productions of TM and anti-TM have been detected. Results The positive of RT-PCR and expressed TM identified the function of the recombinant plasmid. The pcDNA3.1/TM(LEO) induced higher titer of anti-TM. The antibody titer peaked between the 5th and 7th injection with a titer of 1∶8 000 detected by cell-ELISA coated with EVC-304. Specificity has been identified by western blot and immunohistochemistry.Conclusion The production of antibody through genetic immunization was a feasible method due to the difficulties in obtaining and purification of natural thrombomodulin.