Localization of thrombospondin-l and its cysteine-serine-valine-threonine-cysteine-glycine receptor in colonic anastomotic healing tissue

Thrombospondin-l (TSP-1) is a matrix protein implicated in mechanisms of wound healing. TSP-1 contains the sequence cysteine-serine-valinethreonine- cysteine-glycine (CSVTCG) that has been shown to function primarily as a cell adhesion domain. Our laboratory has isolated a novel receptor specific for the CSVTCG adhesive domain of TSP-1. Immunohistochemical staining techniques and computerized image analysis were used to identify and quantitate TSP-1 and its CSVTCG receptor in surgically created colon anastomotic wounds. Histopathologic and quantitative examination demonstrated increased expression of TSP- 1 and its CSVTCG receptor in areas of wound healing. These findings suggest a role for TSP-1 and its CSVTCG receptor in wound healing. The control of expression and activity of these molecules may eventually be the basis for the development of wound healing agents that could significantly reduce the morbidity from surgical intervention

The localization of thrombospondin-1 (TSP-1), cysteine-serine-valine-threoninecysteine- glycine (CSVTCG) TSP receptor, and matrix metalloproteinase-9 (MMP-9) in colorectal cancer

Thrombospondin-1 (TSP-1) is a 450 kDa matrix bound glycoprotein involved in tumor invasion, metastasis, and angiogenesis. One of the receptors involved in TSP-1 mediated tumor cell adhesion and metastasis is the cysteine-serine-valine-threoninecysteine- glycine (CSVTCG) receptor. One mechanism of TSP-1 in promoting tumor cell metastasis involves the up-regulation of matrix metalloproteinase-9 (MMP-9) expression, specifically through the CSVTCG TSP-1 receptor. TSP-1 and its CSVTCG receptor has been implicated in tumor progression in a variety of cancers including breast adenocarcinomas, head and neck squamous cell carcinomas, and pancreatic carcinomas. In this study, we examined 99 cases of colorectal cancer by immunohistochemical analysis to investigate 1) the localization of TSP-1 and CSVTCG TSP-1 receptor, 2) the relationship with MMP-9, and 3) the correlation of expression with clinical staging. Strong expression of TSP-1 was observed in the submucosa or the serosa adjacent to the tumor. Positive staining for CSVTCG TSP-1 receptor was observed in tumor cells and microvessels. MMP-9 was also expressed in tumor cells. In addition, staining intensity of CSVTCG TSP-1 receptor was higher in poorly differentiated adenocarcinoma than well or moderately differentiated adenocarcinoma. Tumors in which inflammatory cells stained strongly for CSVTCG TSP-1 receptor correlated with decreased incidence of distant metastasis and angiogenesis. These data were consistent with our previous studies for breast, pancreatic, and head and neck carcinoma. They suggest an important role for TSP-1 and CSVTCG TSP-1 receptor in tumor progression in colorectal cancer

Histopathology and clinical assessment correlate with the cysteine-serine-valinethreonine- cysteine-glycine (CSVTCG) receptor of thrombospondin-1 in breast tumors

Thrombospondin-1 (TSP-1) is a matrix protein implicated in mechanisms of tumor metastasis. TSP-1 has a characteristic Cysteine-Serine-Valine- Threonine-Cysteine-Glycine (CSVTCG) sequence that functions as a tumor cell adhesion domain. Our laboratory has isolated a novel CSVTCG specific tumor cell receptor. Immunohistochemical staining techniques and computerized image analysis were used to identify and quantitate the CSVTCG receptor of TSP-1 in a wide spectrum of human archiva1 breast tumors. Histopathologic and quantitative examination was correlated with clinical findings two years post operation. Increasing amounts of CSVTCG receptor correlated positively with worsening histopathologic and clinical findings. These findings suggest a role for the TSP-1 CSVTCG receptor in breast tumor progression. This receptor may have utility for the diagnosis, staging, and treatrnent of this common and deadly disease

Nitridergic platelet pathway activation by hementerin, a metalloprotease from the leech Haementeria depressa

Hementerin (HT) is an 80 kDa fibrino(geno)lytic metalloprotease, purified from saliva of the leech Haementeria depressa. in the present report, the effect of HT on several functional parameters of human platelets was assessed. HT inhibited platelet aggregation and ATP release induced by different agonists such as ADP, adrenaline, collagen, thrombin, and arachidonic acid. HT did neither modify the expression of platelet glycoproteins (Ib, IIbIIIa, IaIIa, IV) nor intraplatelet fibrinogen levels, whereas it markedly decreased CD62P and CD63 levels after the stimulation with thrombin. HT significantly increased thrombininduced platelet Ca2+ intracellular levels, cGMP content and nitric oxide synthase (NOS) activity. the effect of HT on platelet aggregation was reversed by two NOS inhibitors, N-omega-Nitro-L-arginine methyl ester and 2 N-G-Nitro-L-arginine. in summary, these results indicate that HT is an effective inhibitor of human platelet aggregation, presumably through activation of the platelets nitridergic pathway.Inst Butantan, Lab Bioquim & Biofis, BR-05503900 São Paulo, BrazilAcad Nacl Med Buenos Aires, IIHEMA, Buenos Aires, DF, ArgentinaUniv Buenos Aires, Fac Med, Dept Bioquim Humana, Buenos Aires, DF, ArgentinaUniversidade Federal de São Paulo, Dept Bioquim, São Paulo, BrazilUniversidade Federal de São Paulo, Dept Bioquim, São Paulo, BrazilWeb of Scienc

Kinesin as an Electrostatic Machine

Kinesin and related motor proteins utilize ATP fuel to propel themselves along the external surface of microtubules in a processive and directional fashion. We show that the observed step-like motion is possible through time-varying charge distributions furnished by the ATP hydrolysis cycle while the static charge configuration on the microtubule provides the guide for motion. Thus, while the chemical hydrolysis energy induces appropriate local conformational changes, the motor translational energy is fundamentally electrostatic. Numerical simulations of the mechanical equations of motion show that processivity and directionality are direct consequences of the ATP-dependent electrostatic interaction between the different charge distributions of kinesin and the microtubule