Role of catalytic function in the antiplatelet activity of phospholipase A(2) cobra (Naja naja naja) venom

Three acidic phospholipases A(2) from Indian cobra (Naja naja naja) venom inhibited platelet aggregation in platelet rich plasma induced separately by ADP, collagen and epinephrine with different potencies. The order of inhibition was epinephrine > collagen > ADP. They did not inhibit platelet aggregation induced by arachidonic acid (10 muM). The inhibition was dependent on concentration of the protein and the time of incubation of the phospholipases A(2) with platelet rich plasma. Parabromophenacyl bromide modified PLA(2) enzymes lost their enzymatic activity as well as platelet aggregation inhibition activity suggesting the involvement of catalytic function in platelet aggregation inhibitory activity

Hydrodynamic delivery of plasmid DNA encoding human FcYR-Ig dimers blocks immune-complex mediated inflammation in mice

Therapeutic use and function of recombinant molecules can be studied by the expression of foreign genes in mice. In this study, we have expressed human FcY receptor-Ig fusion molecules (FcYR-Igs) in mice by administering FcYR-Ig plasmid DNAs hydrodynamically and compared their effectiveness with purified molecules in blocking immune-complex (IC)-mediated inflammation in mice. The concentration of hydrodynamically expressed FcYR-Igs (CD16 A-F-Ig, CD32AR-Ig and CD32AH-Ig) reached a maximum of 130 µg ml-1 of blood within 24 h after plasmid DNA administration. The in vivo half-life of FcYR-Igs was found to be 9-16 days and western blot analysis showed that the FcγR-Igs were expressed as a homodimer. The hydrodynamically expressed FcYR-Igs blocked 50-80% of IC-mediated inflammation up to 3 days in a reverse passive Arthus reaction model. Comparative analysis with purified molecules showed that hydrodynamically expressed FcYR-Igs are more efficient than purified molecules in blocking IC-mediated inflammation and had a higher half-life. In summary, these results suggest that the administration of a plasmid vector with the FcYR-Ig gene can be used to study the consequences of blocking IC binding to FcYRs during the development of inflammatory diseases. This approach may have potential therapeutic value in treating IC-mediated inflammatory autoimmune diseases such as lupus, arthritis and autoimmune vasculitis

Antimicrobial properties of a non-toxic glycoprotein (WSG) from Withania somnifera (Ashwagandha)

Abstract A monomeric glycoprotein with a molecular mass of 28 kDa in SDS-PAGE was isolated from the Withania somnifera root tubers. The protein designated WSG (Withania somnifera glycoprotein) demonstrated potent antimicrobial activity against the phytopathogenic fungi and bacteria tested. Antifungal effect has been demonstrated in that WSG exerts a fungistastic effect by inhibiting spore germination and hyphal growth in the tested fungi. WSG showed potent antifungal activity against Aspergillus flavus, Fusarium oxysporum, F. verticilloides and antibacterial activity against Clvibacter michiganensis subsp. michiganensis. WSG is an acidic, non-toxic (trypsin-chymotrypsin) protease inhibitor. These results encourage further studies of WSG as a potential therapeutic agent for its antifungal activity. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Differential Role of Lipocalin 2 During Immune Complex-Mediated Acute and Chronic Inflammation in Mice

OBJECTIVE: Lipocalin 2 (LCN-2) is an innate immune protein that is expressed by a variety of cells and is highly up-regulated during several pathologic conditions, including immune complex (IC)-mediated inflammatory/autoimmune disorders. However, the function of LCN-2 during IC-mediated inflammation is largely unknown. Therefore, this study was undertaken to investigate the role of LCN-2 in IC-mediated diseases. METHODS: The up-regulation of LCN-2 was determined by enzyme-linked immunosorbent assay in 3 different mouse models of IC-mediated autoimmune disease: systemic lupus erythematosus, collagen-induced arthritis, and serum-transfer arthritis. The in vivo role of LCN-2 during IC-mediated inflammation was investigated using LCN-2-knockout mice and their wild-type littermates. RESULTS: LCN-2 levels were significantly elevated in all 3 of the autoimmune disease models. Further, in an acute skin inflammation model, LCN-2-knockout mice exhibited a 50% reduction in inflammation, with histopathologic analysis revealing notably reduced immune cell infiltration as compared to wild-type mice. Administration of recombinant LCN-2 to LCN-2-knockout mice restored inflammation to levels observed in wild-type mice. Neutralization of LCN-2 using a monoclonal antibody significantly reduced inflammation in wild-type mice. In contrast, LCN-2-knockout mice developed more severe serum-induced arthritis compared to wild-type mice. Histologic analysis revealed extensive tissue and bone destruction, with significantly reduced neutrophil infiltration but considerably more macrophage migration, in LCN-2-knockout mice compared to wild-type mice. CONCLUSION: These results demonstrate that LCN-2 may regulate immune cell recruitment to the site of inflammation, a process essential for the controlled initiation, perpetuation, and resolution of inflammatory processes. Thus, LCN-2 may present a promising target in the treatment of IC-mediated inflammatory/autoimmune diseases

The anti-snake venom properties of Tamarindus indica (leguminosae) seed extract

Abstract In Indian traditional medicine, various plants have been used widely as a remedy for treating snakebites. The aim of this study was to evaluate the effect of Tamarindus indica seed extract on the pharmacological as well as the enzymatic effects induced by V. russelli venom. Tamarind seed extract inhibited the PLA2, protease, hyaluronidase, l-amino acid oxidase and 5′-nucleotidase enzyme activities of venom in a dose-dependent manner. These are the major hydrolytic enzymes responsible for the early effects of envenomation, such as local tissue damage, inflammation and hypotension. Furthermore, the extract neutralized the degradation of the Bβ chain of human fibrinogen and indirect hemolysis caused by venom. It was also observed that the extract exerted a moderate effect on the clotting time, prolonging it only to a small extent. Edema, hemorrhage and myotoxic effects including lethality, induced by venom were neutralized significantly when different doses of the extract were preincubated with venom before the assays. On the other hand, animals that received extract 10 min after the injection of venom were protected from venom induced toxicity. Since it inhibits hydrolytic enzymes and pharmacological effects, it may be used as an alternative treatment to serum therapy and, in addition, as a rich source of potential inhibitors of PLA2, metalloproteinases, serine proteases, hyaluronidases and 5¢-nucleotidases, the enzymes involved in several physiopathological human and animal diseases. Copyright © 2006 John Wiley & Sons, Ltd