Fusion with an albumin-binding domain improves pharmacokinetics of an αvß3-integrin binding fibronectin scaffold protein.

Fusion with an albumin-binding domain (ABD) of streptococcal protein G represents a popular approach for half-life extension of small protein therapeutics in the organism. To increase the circulation time of engineered αvß3-integrin-binding protein (JCL) based on the 10th human fibronectin type III domain (10 Fn3), we have constructed several fusions with ABD with different orientations of the partner proteins and linker length. The recombinant proteins were expressed in Escherichia coli cells and purified by nickel-affinity chromatography. All fusion proteins bound human serum albumin (HSA) in ELISA assay; however, fusions with longer linkers demonstrated better performance. Interaction of ABD-L15 -JCL and JCL-L14 -ABD with HSA was confirmed by analytical size exclusion chromatography and pull-down assays. Surprisingly, the thermal stability of ABD-L15 -JCL was dramatically decreased in comparison with JCL and JCL-L14 -ABD proteins. Pharmacokinetic studies revealed that JCL-L14 -ABD circulated in murine blood about 10 times longer than ABD-L15 -JCL and 960 times longer than JCL. Biodistribution studies of JCL-L14 -ABD in mice revealed its increased level in blood and a decreased accumulation in liver and kidneys in comparison with JCL. Obtained results demonstrate the utility of the fusion with ABD for half-life extension of the binding proteins based on 10 Fn3.

Construction of Artificial TNF-Binding Proteins Based on the 10th Human Fibronectin Type III Domain Using Bacterial Display.

Construction of antibody mimetics on the base of alternative scaffold proteins is a promising strategy for obtaining new products for medicine and biotechnology. The aim of our work was to optimize the cell display system for the 10th human fibronectin type III domain (10Fn3) scaffold protein based on the AT877 autotransporter from Psychrobacter cryohalolentis K5T and to construct new artificial TNF-binding proteins. We obtained a 10Fn3 gene combinatorial library and screened it using the bacterial display method. After expression of the selected 10Fn3 variants in Escherichia coli cells and analysis of their TNF-binding activity, we identified proteins that display high affinity for TNF and characterized their properties.

[Dimebon correction of changes in phospholipid composition induced by tumor necrosis factor-alpha in experement]. / Korrektsiia dimebonom narushenii sostava fosfolipidov v strukturakh mozga, vyzvannykh faktorom nekroza opukholi α v éksperimente.

AIM: To investigate the ability of the neuroprotector dimebon to prevent alterations in brain lipid metabolism caused byTNF-α. MATERIAL AND METHODS: The ability of dimebon (2,8-Dimethyl-5-[2-(6-methyl-3-pyridinyl)ethyl]-2,3,4,5-tetrahydro-1H-pyrido[4,3-b]indole hydrochloride) to prevent alterations in brain lipid metabolism caused byTNF-α was studied in 65 male mice (20+2g weight). TNF-α (10 mkg/mouse), dimebon (0.2 mg/kg) and their combination were injected intraperitoneally. Thirty min, 2, 4 and 24 h after injection, lipid level alterations in total fractions and molecular species of phospholipids (phosphatidylcholine, lysophosphatidylcholine, sphingomyelin and phosphatidylethanolamine) were measured with mass-spectrometry in the hippocampus, cortex and cerebellum. RESULTS AND CONCLUSION: After injection of TNF-α into mice, there are significant changes in the level of all tested phospholipids. Dimebon at a dose of 0.2 mg/kg alone does not cause any changes in the content of all tested phospholipids, but injected together with TNF-α prevents cytokine induced alterations in the lipid content. The selectivity of TNF-α and dimebon influence on certain molecular species of various phospholipids in different parts of mouse brain is found. The presented data suggest protective properties of dimebon preventing the development of proinflammatory syndrome induced by TNF-α in the animal brain.

The Effect of TNF and VEGF on the Properties of Ea.hy926 Endothelial Cells in a Model of Multi-Cellular Spheroids.

Endothelial cells play a major role in the development of inflammation and neoangiogenesis in cancer and chronic inflammatory diseases. In 3D cultures, cells are under conditions that closely resemble those existing in healthy and disease-stricken human organs and tissues. Therefore, the development of a 3D model based on the Ea.hy926 endothelial cell line is an urgent need in molecular and cellular biology. Cell cultivation on an anti-adhesive substrate under static conditions was shown to lead to the formation of spheroids (3D cultures). Expression of ICAM-1 and VEGFR-2 and production of cytokines were screened in 2D and 3D cultures in the presence of TNF and VEGF. According to flow cytometry and confocal microscopy data, TNF significantly increased the expression of the cell adhesion molecule ICAM-1 in both 2D and 3D cultures but did not affect the expression level of VEGFR-2. Increased production of pro-inflammatory (IL-8, IL-6, IP-10) and anti-inflammatory (IL-10, TGF-ß 1-3) factors was observed in spontaneous 3D cultures but not in 2D cultures, which was confirmed by flow cytometry and qPCR. TNF-induced secretion of IL-10, GM-CSF, and IL-6 was 11-, 4.7-, and 1.6-fold higher, respectively, in 3D cultures compared to 2D cultures. Thus, the use of a Ea.hy926 3D cell culture is a promising approach in studying the effects of anti- and pro-inflammatory agents on endothelial cells.

Fusion with the cold-active esterase facilitates autotransporter-based surface display of the 10th human fibronectin domain in Escherichia coli.

Cell surface display is a popular approach for the construction of whole-cell biocatalysts, live vaccines, and screening of combinatorial libraries. To develop a novel surface display system for the popular scaffold protein 10th human fibronectin type III domain (10Fn3) in Escherichia coli cells, we have used an α-helical linker and a C-terminal translocator domain from previously characterized autotransporter from Psychrobacter cryohalolentis K5T. The level of 10Fn3 passenger exposure at the cell surface provided by the hybrid autotransporter Fn877 and its C-terminal variants was low. To improve it, the fusion proteins containing 10Fn3 and the native autotransporter passenger Est877 or the cold-active esterase EstPc in different orientations were constructed and expressed as passenger domains. Using the whole-cell ELISA and activity assays, we have demonstrated that N-terminal position of EstPc in the passenger significantly improves the efficiency of the surface display of 10Fn3 in E. coli cells.

[Tumor necrosis faсtor-alpha - potential target for neuroprotector dimebon]. / Faktor nekroza opukholei-al'fa - potentsial'naia mishen' dlia neiroprotektora dimebona.

Dimebon (Dimebolin) is an antihistamine drug which has been used in Russia since 1983. Recently Dimebolin has attracted renewed interest after being shown to have positive effects on persons suffering from Alzheimer's disease. Animal studies have shown that dimebon acts through multiple mechanisms, both blocking the action of neurotoxic beta-amyloid peptides and inhibiting L-type calcium channels, modulating the action of AMPA and NMDA glutamate receptors. Our experiments with cell culture L929 and mice have shown that dimebon may exert its neuroprotective effect by blocking cytotoxic signals induced by proinflammatory cytokines such as TNF-a which are believed to play a central role in Alzheimer's disease. Dimebon (10 mg/ml) protected mouse fibroblasts L929 against the toxic action of TNF-a. Our study included 65 male mice. TNF-a (10 mg per mouse), dimebon (0,2 mg/kg) and their combination were injected intraperitonealy. Changes in the level of molecular species of sphingomyelin and galactosyl ceramide in hippocampus, cerebellum and cerebral cortex within 30 min, 2 h, 4 h, and 24 h after injection were detected by chromato-mass-spectrometry. Maximal changes in sphingomyelin and galactosyl ceramides contents of different molecular species after single TNF-a administration were found in the hippocampus, and were less expressed in the cerebral cortex and cerebellum after 24 h. Dimebon itself did not induce changes in the sphingolipid spectrum in brain sections, but protected them against disorders induced by TNF-a in the brain. Modern strategies in the search of new therapeutic approaches are based on the multitarget properties of new drugs. According to our results TNF-a may serve as a new target for dimebon.

[Fluorescent fusion proteins with 10th human fibronectin domain].

In the current paper we describe a new type of hybrid molecules including red fluorescent protein mCherry and 10th type III human fibronectin domain (10Fn3) - one of the alternative scaffold proteins which can be used for the construction of antibody mimics with various binding specificity. We have constructed different gene variants encoding for the hybrid fluorescent protein and studied their expression in Escherichia coli cells. It was shown that N-terminal position of mCherry and modification of its N-terminal amino acid sequence promotes efficientbacterial expression of the hybrid protein in the soluble form. On the basis of the proposed construction we have obtained the hybrid fluorescent protein ChIBF, containing alphaVbeta3-integrin binding vari- ant of 10Fn3, and demonstrated the possibility of its utilization for the visualization of alphaVbeta3-integrin at the surface of MDCK epithelial cells by confocal microscopy.

[The combined application of nucleotide and amino acid sequences of NS3 hepatitis C virus protein, DNA encoding granulocyte macrophage colony-stimulating factor and inhibitor of regulatory T cells induces effective immune response against hepatitis C virus].

Hepatitis C is related to the most important socially significant human infectious diseases; however, vaccine against this virus up to now has notbeen created. One of the possible components of vaccine is the nonstructural protein NS3 of hepatitis C virus (HCV), which is synthesized in the infected cells and displays protease, NTPase, and helicase enzymatic activities. The connection between the effectiveness ofT cellular response to NS3 epitopes and the spontaneous resolution of acute hepatitis C was shown. The purpose of this work was to compare the immune response of mice to the inoculation of nucleotide and amino acid sequences of HCV NS3 and their combination, to evaluate the adjuvant activity of the DNA encoding granulocyte macrophage colony-stimulating factor (GM-CSF) and the influence of regulatory T cells on the effectiveness of immune response. The maximum anti-HCV NS3 antibody level in the serum (to 1:640000) induced the recombinant protein rNS3 introduced with aluminum hydroxide. The most intensive cellular immune response was observed after the simultaneous administration of rNS3 and DNAs encoding full-size NS3 and GM-CSF. A high level of lymphocyte proliferation, accumulation of IFN-gamma-secreting cells and IFN-gamma, and IL-2 release in response to the stimulators--NS3 antigens of different composition were observed in this group of mice. It has been established that the suppression of regulatory T cells in vitro leads to the statistically significant increase in the secretion of IFN-gamma. Thus, simultaneous application of rNS3 along with the DNAs encoding full-size NS3 and GM-CSF is promising approach for development of hepatitis C vaccine. The expediency of inclusion in the vaccine composition of regulatory T cell inhibitors will be clear after special studies.

Construction of TNF-binding proteins by grafting hypervariable regions of F10 antibody on human fibronectin domain scaffold.

Tumor necrosis factor (TNF) plays a key role in the pathogenesis of various diseases. To study the possibility of constructing TNF-binding proteins by grafting hypervariable regions of immunoglobulins (CDR), we have replaced amino acid sequences of loops from the tenth type III domain of human fibronectin ((10)Fn3) by amino acid sequences of CDR from the light and heavy chains of the anti-TNF antibody F10. The assessment of TNF-binding properties of the resulting proteins by ELISA has revealed the highest activity of Hd3 containing sequences CDR-H1 and CDR-H2 of the antibody F10 and of Hd2 containing sequences CDR-H1 and CDR-H3. The proteins constructed by us on the fibronectin domain scaffold specifically bound TNF during Western blotting and also weakened its cytotoxic effect on L929 line cells. The highest neutralizing activity was demonstrated by the proteins Hd2 and Hd3, which induced, respectively, 10- and 50-fold increase in the EC(50) of TNF.

Lipid-protein nanodiscs for cell-free production of integral membrane proteins in a soluble and folded state: comparison with detergent micelles, bicelles and liposomes.

Production of integral membrane proteins (IMPs) in a folded state is a key prerequisite for their functional and structural studies. In cell-free (CF) expression systems membrane mimicking components could be added to the reaction mixture that promotes IMP production in a soluble form. Here lipid-protein nanodiscs (LPNs) of different lipid compositions (DMPC, DMPG, POPC, POPC/DOPG) have been compared with classical membrane mimicking media such as detergent micelles, lipid/detergent bicelles and liposomes by their ability to support CF synthesis of IMPs in a folded and soluble state. Three model membrane proteins of different topology were used: homodimeric transmembrane (TM) domain of human receptor tyrosine kinase ErbB3 (TM-ErbB3, 1TM); voltage-sensing domain of K(+) channel KvAP (VSD, 4TM); and bacteriorhodopsin from Exiguobacterium sibiricum (ESR, 7TM). Structural and/or functional properties of the synthesized proteins were analyzed. LPNs significantly enhanced synthesis of the IMPs in a soluble form regardless of the lipid composition. A partial disintegration of LPNs composed of unsaturated lipids was observed upon co-translational IMP incorporation. Contrary to detergents the nanodiscs resulted in the synthesis of ~80% active ESR and promoted correct folding of the TM-ErbB3. None of the tested membrane mimetics supported CF synthesis of correctly folded VSD, and the protocol of the domain refolding was developed. The use of LPNs appears to be the most promising approach to CF production of IMPs in a folded state. NMR analysis of (15)N-Ile-TM-ErbB3 co-translationally incorporated into LPNs shows the great prospects of this membrane mimetics for structural studies of IMPs produced by CF systems.

[Human single chain antibodies directed to tumor necrosis factor].

Six unique phage antibodies to human TNF have been selected from a combinatorial library of human single chain fragment variable. ELISA and Western-blotting was used to study selected phage antibodies binding with TNF. The specificity of selected antibodies was determined by binding with interferon alpha and gamma, bovine serum albumin, ovalbumin and ubiquitin. Two antibodies, sA1 and sB3, were converted into a soluble single-chain antibody form and their affinity was 2.5 and 13.7 nM respectively.

[Alternative scaffold proteins].

Review is devoted to the challenging direction in modem molecular biology and bioengineering - the properties of alternative scaffold proteins (ASP) and methods for obtaining ASP binding molecules. ASP molecules incorporate conservative protein core and hypervariable regions, providing for the binding function. Structural classification of ASP includes several types which differ also in their molecular targets and potential applications. Construction of artificial binding proteins on the ASP basis implies a combinatorial library design with subsequent selection of specific binders with the use of phage display or the modem cell-free systems. Alternative binding proteins on non-immunoglobulin scaffolds find broad applications in different fields ofbiotechnology and molecular medicine.

[Production and properties of human tumor necrosis factor peptide fragments].

The tumor necrosis factor (TNF) is a proinflammatory cytokine that plays a pivotal role in the regulation of the human immune system. Studies of the TNF functional topography are a challenging task in bioengineering. We have produced genes encoding the peptides Dl (3-30), D2 (31-85), D3 (86-114), and D4 (115-157), which correspond to isolated fragments of the informational structure of TNF. These genes were expressed in E. coli cells at a high level in a soluble form. We have shown that hybrid proteins SD2 and SD4 tend to form soluble aggregates, which can be destroyed by urea treatment. Purified peptides Dl, D3, and D4 possess a similar secondary structure with dominating beta-structural elements. The analysis of the biological activity of these peptides has shown that they do not exhibit cytotoxic properties on L929 murine fibroblasts. The simultaneous addition of Dl with full-length TNF results in the concentration dependent suppression of TNF activity.

Novel mutants of human tumor necrosis factor with dominant-negative properties.

Tumor necrosis factor (TNF) is a polyfunctional cytokine, one of the key mediators of inflammation and innate immunity. On the other hand, systemic or local TNF overexpression is typical of such pathological states as rheumatoid arthritis, psoriasis, Crohn's disease, septic shock, and multiple sclerosis. Neutralization of TNF activity has a marked curative effect for some diseases; therefore, the search for various TNF blockers is a promising field of protein engineering and biotechnology. According to the previously developed concept concerning the possibility of designing dominant-negative mutants, the following TNF variants have been studied: TNFY87H + A145R, TNFY87H + A96S + A145R, and TNFV91N + A145R. All of these form inactive TNF heterotrimers with the native protein. The ability of mutants to neutralize the effect of TNF was investigated. The addition of mutants to the native protein was shown to provide a concentration-dependent suppression of TNF cytotoxicity against the mouse fibroblast cell line L929. Thus, novel inhibitors of human TNF can be engineered on the basis of these muteins.

Production of biologically active human myelocytokines in plants.

An effective system for expression of human granulocyte and granulocyte macrophage colony-stimulating factors (hG-CSF and hGM-CSF) in Nicotiana benthamiana plants was developed using viral vector based on tobacco mosaic virus infecting cruciferous plants. The genes of target proteins were cloned into the viral vector driven by actin promoter of Arabidopsis thaliana. The expression vectors were delivered into plant cells by agroinjection. Maximal synthesis rate was detected 5 days after injection and was up to 500 and 300 mg per kg of fresh leaves for hG-CSF and hGM-CSF, respectively. The yield of purified hG-CSF and hGM-CSF was 100 and 50 mg/kg of fresh leaves, respectively. Recombinant plant-made hG-CSF and hGM-CSF stimulated proliferation of murine bone marrow and human erythroleucosis TF-1 cells, respectively, at the same rate as the commercial drugs.

[Mechanism of interaction of tumor necrosis factor (TNF-alpha) of macroorganism with the Salmonella enterica cells (ser. Typhimurium)].

The goal of this work was to elucidate the mechanism of direct interaction of bacterial cells with tumor necrosis factor (TNF-alpha; cytokine). It was shown earlier that this interaction facilitated activation of bacterial growth and recultivation of non-cultivated forms in vitro and in vivo. It was shown in experiments with mice deficient in the genes encoding eucaryotic TNF-alpha receptors and infected with salmonella that addition of exogenous TNF-alpha to suspension of infection cells caused a one-day acceleration in the infection start (bacteria planting from spleen) in both knockouted and control mice relative to the same animals infected with the same bacteria without cytokine. Thus, bacteria are able to interact with cytokine even in the absence of eucaryotic receptors. Specificity of the bacterium-cytokine interaction and bacterial protein EF-Tu mediating direct interaction of bacteria with cytokine were identified using the method of immobilization of recombinant protein TNF-alpha-spacer-CSD on cellulose.

[Recombinant full-size human antibody to Ebola virus].

A full-size human antibody to Ebola virus was constructed by joining genes encoding the constant domains of the heavy and light chains of human immunoglobulin with the corresponding DNA fragments encoding variable domains of the single-chain antibody 4D1 specific to Ebola virus, which was chosen from a combinatorial phage display library of single-strand human antibodies. Two expression plasmids. pCH1 and pCL1, containing the artificial genes encoding the light and heavy chains of human immunoglobulin, respectively, were constructed. Their cotransfection into the human embryonic kidney cell line HEK293T provided the production of a full-size recombinant human antibody. The affinity constant for the antibody was estimated by solid-phase enzyme-linked immunoassay to be 7.7 x 10(7) +/- 1.5 x 10(7) M(-1). Like the parent single-chain antibody 4DI, the resulting antibody bound the nucleoprotein of Ebola virus and did not interact with the proteins of Marburg virus.

The relation between sphingomyelinase activity, lipid peroxide oxidation and NO-releasing in mice liver and brain.

We used animal models to study connection between oxidating system and sphingomyelin signaling cascade, because this models are more close related to people disease. Activation of n-sphingomyelinase (n-SMase) in mice liver and brain is coincided in time with increased level of peroxide products (conjugated dienes) after injection of tumor necrosis factor alpha (TNF-alpha). We found that ceramide can induce peroxide oxidation and lead to accumulation of TNF-alpha in animal organs. Nitric oxide (NO) donors (S-nitrosoglutathione and dinitrosyl iron complex) reversibly inhibited activity of n-SMase and decreased level of lipid peroxidation products. This data proposed that both SMase and messengers of oxidative systems could be targets for NO-derived oxidants.