Inhibition of zymosan-induced air-pouch inflammation by rat seminal vesicle protein and by its spermidine derivative

The N-terminal 1-16 peptide derived in vivo from protein seminal vesicle protein IV modulates alpha-thrombin activity: potential clinical implications

We have previously shown that seminal vesicle protein IV (SV-IV) and its 1-70 N-terminal fragment have anti-inflammatory activity and modulate anti-thrombin III (AT) activity. Moreover, mass spectrometry analysis of purified SV-IV has shown that the protein was found to be highly heterogeneous and 14% of the total SV-IV molecules are truncated forms, of particular interest the 1-16, 1-17, and 1-18 peptides. In this work we report experimental data which demonstrate that the 1-16 peptide (P1-16) possesses a marked effect on the AT activity by preventing the formation of the thrombin-AT complex. We found that the formation of thrombin-AT complex is markedly decreased in the presence of P1-16 used at equimolar concentration with thrombin as evaluated with SDS-PAGE. We also monitored the conformational changes of thrombin in the presence of different P1-16 concentrations, and calculated the K(d) of thrombin/P1-16 system by circular dichroism technique. The probable interaction sites of P1-16 with thrombin have been also evaluated by molecular graphics and computational analyses. These results have potential implications in the treatment of sterility and thrombotic diseases.

Synthesis and resistance to in vitro proteolysis of transglutaminase cross-linked phaseolin, the major storage protein from Phaseolus vulgaris

The ability of phaseolin to act as an acyl donor and acceptor substrate of transglutaminase was studied by using an enzyme isolated from Streptoverticillium mobarense. Phaseolin, a trimeric storage protein from Phaseolus vulgaris L., was shown to possess both glutamine and lysine residues reactive for the enzyme. The extent of transglutaminase-catalyzed cross-linking has been studied in function of both incubation time and enzyme concentration. Native- and SDS-PAGE demonstrated that phaseolin is intra- and intermolecularly cross-linked by transglutaminase and gives rise to different polymers as well as to modified forms of the protein having a similar molecular weight but lower Stokes radius if compared to unmodified phaseolin. Cross-linked phaseolin was found to be more resistant to proteolytic cleavage than the unmodified counterpart, as demonstrated by in vitro trypsin and pepsin digestion experiments. This behavior could suggest novel possible uses of the transglutaminase-modified phaseolin.

Transglutaminase-catalyzed site-specific glycosidation of catalase with aminated dextran

An enzymatic approach, based on a transglutaminase-catalyzed coupling reaction, was investigated to modify bovine liver catalase with an end-group aminated dextran derivative. We demonstrated that catalase activity increased after enzymatic glycosidation and that the conjugate was 3.8-fold more stable to thermal inactivation at 55 degrees C and 2-fold more resistant to proteolytic degradation by trypsin. Moreover, the transglutaminase-mediated modification also improved the pharmacokinetics behavior of catalase, increasing 2.5-fold its plasma half-life time and reducing 3-fold the total clearance after its i.v. administration in rats.

Transglutaminase-catalyzed synthesis of trypsin-cyclodextrin conjugates: kinetics and stability properties

Bovine pancreatic trypsin was modified by the mono-6-amino-6-deoxy derivatives of alpha-, beta-, and gamma-cyclodextrin through a transglutaminase-catalyzed reaction. The trypsin-cyclodextrin conjugates, containing about 3 mol of oligosaccharide per mole of protein, were tested for their catalytic and stability properties. The specific esterolytic activity and the kinetics constants of trypsin were significantly improved following the transglutaminase-induced structural modifications. Trypsin-cyclodextrin conjugates were also found markedly (sixfold) more resistant to autolytic degradation at alkaline pH, and their thermal stability profile was improved by about 16 degrees C. Moreover, they were particularly resistant to heat inactivation when treated at different temperatures ranging from 45 degrees C to 70 degrees C for different periods of time.

Protein SV-IV promotes nitric oxide production not associated with apoptosis in murine macrophages

SV-IV (seminal vesicle protein no. 4) is a potent immunomodulatory and anti-inflammatory secretory protein (Mr 9758) produced in large amounts by the rat seminal vesicle epithelium. Here we show that this protein possesses the ability to upregulate in J774 macrophages the expression of the gene coding for the inducible nitric oxide synthase (iNOS). The increase in NO production consequent on the marked enhancement of iNOS activity was not associated with apoptotic damage of the SV-IV-treated cells. In the same experimental model, however, LPS induced upregulation of iNOS coupled with an increase in NO production and marked apoptotic death. Differences in the ability of SV-IV and LPS to control the life/ death signal balance in target cells via trans-membrane activation of apoptotic (mediated by TNF-alpha and NO/iNOS system) and anti-apoptotic (mediated by bcl-2, c-myc, etc.) pathways are suggested to be the basis of the apoptotic fate of the experimentally treated cells. In addition, considering the important role played by NO in the process of mammalian reproduction, SV-IV may be involved in the fine tuning of NO concentration in the female genital tract mucosa via an SV-IV-mediated control of iNOS gene expression in local macrophages.

Effect of protein SV-IV on experimental Salmonella enterica serovar Typhimurium infection in mice

Seminal vesicle protein IV (SV-IV) is a secretory anti-inflammatory, procoagulant, and immunomodulatory protein produced in large amounts by the seminal vesicle epithelium of the rat under the strict transcriptional control of androgen. In particular, this protein was shown to possess the ability to markedly inhibit in vivo the humoral and cell-mediated immune responses of mice to nonbacterial cellular antigens (sheep erythrocytes and spermatozoa). We report data that demonstrate that in mice treated with SV-IV and infected with Salmonella enterica serovar Typhimurium, SV-IV is able to downregulate some important immunological and biochemical parameters that serovar Typhimurium normally upregulates in these animals. This event did not correlate with a lower bacterial burden but was associated with a markedly increased one (300%). Furthermore, the treatment of mice with SV-IV alone also produced a significant increase in the rate of mortality among serovar Typhimurium-infected animals. The mechanism underlying these phenomena was investigated, and the strong immunosuppression produced by SV-IV in serovar Typhimurium-infected mice was suggested to be the basis for the increased rate of mortality. The SV-IV-mediated immunosuppression was characterized by a decrease in the humoral and cell-mediated immune responses, altered lymphocyte-macrophage interaction, downregulation of cytokine and inducible nitric oxide synthase gene expression, inhibition of macrophage phagocytosis and intracellular killing activities, and absence of apoptosis in the splenocyte population of SV-IV- and serovar Typhimurium-treated mice. The immunosuppressive activity of SV-IV was specific and was not due to aspecific cytotoxic effects. SV-IV-specific receptors (K(d) = 10(-8) M) occurring on the macrophage and lymphocyte plasma membranes may be involved in the molecular mechanism underlying the SV-IV-mediated immunosuppression. Some results obtained by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay also revealed a functional impairment of mitochondria (a decrease in mitochondrial dehydrogenase activity), thus indicating the possible implication of these organelles in the immunosuppressive process.

Synthesis of novel anti-inflammatory peptides derived from the amino-acid sequence of the bioactive protein SV-IV

SV-IV is a basic, thermostable, secretory protein of low Mr (9758) that is synthesized by rat seminal vesicle (SV) epithelium under strict androgen transcriptional control. This protein is of obvious pharmacological interest because it has potent nonspecies-specific immunomodulatory, anti-inflammatory, and pro-coagulant activities. In evaluating the clinical relevance and the possible use in medicine of SV-IV, we became interested in the study of its structure-function relationships and aimed to identify in its polypeptide chain specific peptide fragments possessing the marked anti-inflammatory properties of the protein not associated with other biological activities (pro-coagulation and immunomodulation) typical of this molecule. By using two different experimental approaches (the fragmentation of the protein into peptide derivatives by chemical methods and the organic synthesis on solid phase of selected peptide fragments), data were obtained showing that in this protein: (a) the immunomodulatory activity is related to the structural integrity of the whole molecule; (b) the anti-inflammatory activity is located in the N-terminal region of the molecule, the 8-16 peptide fragment being the most active; (c) the identified anti-inflammatory peptide derivatives do not seem to possess pro-coagulant activity, even though this particular function has been located in the 1-70 segment of the molecule.