Novel derivative of Danshensu acts as anti-thrombotic agent for modulation of protein disulfide isomerase family member ERp57

OBJECTIVE To identify the specific targets of a novel derivative of Danshensu ADTM as the protein disulfide isomerase(PDI)family proteins including ERp57.To further investigate the underlying mechanism of ADTM to modulate ERp57 to regulate platelet function with direct interaction withαⅡbβ3 integrin.METHODS To isolate the protein targets that bound to ADTM,a biotin-conjugated ADTM analogue(BAA)was designed and synthesized.BAA(300μmol·L-1)was incubated with rat blood platelet lysates and the BAA-protein complexes were pulled down with NeutrAvidin-agarose followed by protein profiling using LC-MS/MS.To determine platelet aggregation in vitro,rabbit platelets were incubated with the indicated concentrations of compounds and aggregation was induced by ADP(10μmol·L-1)or AA(200μmol·L-1)and measured using a platelet aggregometer.To determine platelet aggregation-induced by ADP in rat in vivo,ADTM(5-20mg·kg-1)in comparison with DSS(10mg·kg-1)and clopidogrel(18mg·kg-1)were administered daily by i.v.injection for 5d,respectively.To determine the action of ADTM on the ERp57/αⅡbβ3 interaction,it was examined by immunoprecipitation with anti-αⅡbβ3antibody,followed by detection of ERp57 immunoreactivity using immunoblotting.RESULTS BAA could bind to various proteins involved in platelet function.In particular,platelet aggregation-associated proteins were identified with>95% protein identification probability including ERp72,ERp57ERp5 and PDI,which are members of the protein disulfide isomerase(PDI)family related to platelet function and redox homeostasis.ADTM exhibited potent inhibition on the redox activity of ERp57 in a concentration-dependent manner(IC50=100 300μmol·L-1).In in vitro studies,ADTM exhibited concentration-dependent inhibition on ADP-induced and AA-induced platelet aggregation with comparable effects to aspirin and clopidogrel.In vivo study showed that ADP-induced platelet aggregation was significantly compromised(>40%reduction)in rats treated with ADTM(20mg·kg-1).Similarly,ADTM also exhibited significant anti-thrombotic effect in vivo as shown in the ferric chloride(FeCl3)-induced venous thrombosis.Immunoprecipitation with anti-αⅡbβ3antibody,followed by detection of ERp57 immunoreactivity using immunoblotting showed that ADTM disrupted the interaction of ERp57 with αⅡ bβ3.CONCLUSION These results demonstrated that ADTM exhibited broad-spectrum anti-platelet activities and ERp57 is a potential therapeutic target for anti-platelet therapy.

Cerium oxide nanoparticles coated by surfactant sodium bis（2—ethylhexyl） sulphosuccinate（AOT）：local atomic structures and x—ray absorption spectroscopic studies

Cerium oxide nanoparticles coated by sodium bis(2-ethylexyl) sulphosuccinate(AOT) were prepared by using a microemulsion method.Transmission electron microscopy revealed an average particle siae of 2-3nm.X-ray diffraction showed that the cerium oxide nanoparticles retain the CeF2-type cubic structures like the bulk crystal.The intermediate valence offormally tetravalent compounds had been detected by x-ray-absorption near-edge structetravalent compounds had been detected by x-ray-absorption near-dege structure(XANES) spectra of Ce LIII absorption in bulk CeO2 and the cerium oxide nanoparticles.Two well resoved white lines can be assigned to the electron configurations of 4f^0L and 4f^1L,respectively,where L denotes a ligand hole.At the same time,the cerium oxide nanoparticles also showed the structural featres of trivalent compounds,in comparison to the trivalent Ce(NO3)3·6H2O.Fuor Lorentzian functions and two arctan functions were used to fit the normalized XANES spectra.The extended x-ray-absorption fine-structure(EXAFS) technique was used to probe the local atomic structures around the absorber Ce.The multielectrorn excitation effect on the EXAFS spectra was eliminated.A cor-shell model was used to deduce the near-neighbour structural parameters around cerium.Bulk CeO2 with eight oxygen atoms located at 2.343A was used as the reference sample to extract the backscattering amplitude and phase shift of the Ce-O bond.One half of the atome locate at the core part with the CeF2-type cubic structures(eight oxyens at 2.343A around Ce),the other half of the atoms are amorphous phase located in the shell part (surface of the nanoparticles) with approximately Ce2O3 structural features (averageed seven oxygens at 2.50A around Ce).

The effect of surface modification on femtosecond optical Kerr effect of PBS nanoparticles

PbS nanoparticles modified by a polymer (P-PbS) was prepared,and the transient nonlinear optical properties studied by femtosecond optical Kerr effect(OKE) spectroscopy for the first time.A very large nonlinear optical effect(X^(3)-5.6×10^-12esu) with response time comparable to the laser pulse(-165fs) was observed.Comparing with PbS nonoparticles stabilized with PVA and coated with sodium dodecyle benzene sulphonate(DBS).the optical nonlinearity of the PbS nanoparticles modified by the polymer is much larger than those of them.Thereafter.the corresponding nonlinearity mechanism was interpreted.

Evaluation of a Rat Model of Experimental Autoimmune Encephalomyelitis with Human MBP as Antigen

Experimental autoimmune encephalomyelitis(EAE) is a good model for human multiple sclerosis(MS) research.However,there are some defects in the traditional models.Here,we improved the model by using the human myelin basic protein(MBP) as antigen.EAE was induced by immunization of female Wistar rats with human MBP.Compared with the traditional models,the new model was evaluated by clinical signs to pathological changes.The immune state of the model was assessed by the lymphocyte infiltrative response and levels of TNF-α,IFN-γ,IL-10.It was found that most of rats exhibited tail tone loss and hind-limb paralysis, also there were demyelination,infiltrative lymphocyte foci,“neuronophagia”in the cortex of cerebra and the white matter of spinal cords.PBMCs and spleen lymphocytes were strongly responsive to the stimulation of MBP and PHA.The levels of TNF-α and IFN-γ were altered with the severity of EAE.In the remitting phase, IL-10 was increased significantly.This study demonstrates that the animal model of EAE induced by human MBP bears resemblance to the features of human multiple sclerosis and promises to be a better model than ever before for the study of MS.Cellular & Molecular Immunology.2004;1(5):387-391.