Effect of cigarette smoke extract on the interaction between thrombomodulin and thrombin by live-cell single-molecule force spectroscopy / 中国药理学通报

ABSTRACT

Aim To study the effect of CSE ( cigarette smoke extract ) on the single-molecule interactional force between thrombomodulin and thrombin by live-cell single-molecule force spectroscopy. Methods CSE was prepared by a previously reported method. The plasmid of TM-GFP was constructed and transfect-ed in COS-7 cells. The expression of TM-GFP was de-tected by fluorescence microscopy and laser scanning confocal microscopy. The transfected COS-7 cells were grouped ( 1 ) GFP -thrombin group ( 2 ) TM-thrombin group ( 3 ) CSE-TM-thrombin group ( 4 ) CSE- GFP-thrombin group. Force measurements with the thrombin modified AFM tips on the living cell surface were car-ried out on PicoSPM II with a Pico-Scan 3000 control-ler and a larger scanner. The force curves measured in living cells were recorded by PicoScan 5 software and analyzed by MATLAB R2009aMetlab. Results The single-molecule binding force of thrombomodulin and thrombin ( TM-Thr ) was determined ( 60. 90 ± 0. 82 ) pN. The binding probability for TM-Thr was about (22. 58 ± 3. 95)%. Antibody blocking binding proba-bility for TM-Thr was ( 2. 58 ± 2. 0 )%. The binding probabilities for GFP-Thr group, CSE-TM-Thr group and CSE-GFP-Thr group were significantly decreased compared with TM-Thr group ( P<0. 05 ) . The mean value of the most probable single molecular interaction force of thrombin/TM-ECD was determined as ( 45. 30 ± 1. 37 ) pN, the binding probability of thrombin and TM-ECD was ( 23. 25 ± 7. 02 )%. When the binding was blocked with the TM-MAb solution, the binding probability decreased to ( 4. 64 ± 2. 31 )%. The bind-ing probability was ( 8. 31 ± 1. 06 )% in the CSE-TM-thr-S group. When further blocked with TM-MAb, the binding probability was ( 5. 17 ± 2. 96 )%. Conclusion CSE significantly decreases the binding probability for TM-Thr to induce intravascular thrombosis.