Synthesis of conjugates of (aR,7S)-colchicine with monoterpenoids and investigation of their biological activity

Conjugates of the natural alkaloid (aR,7S)-colchicine with bicyclic monoterpenoids and their derivatives were synthesized for the first time. Molecular docking of the synthesized agents in the active site of the main viral protease of the SARS-CoV-2 virus was carried out. The cytotoxic properties of the agents against different cell lines and the ability to inhibit the main viral protease 3CLPro were studied.

Proof-of-Concept Study of Liposomes with a Set of SARS-CoV-2 Viral Peptidic T-Cell Epitopes as a Vaccine

Potential nonameric epitopes of CD8⁺ T lymphocytes were selected from the composition of structural, accessory, and nonstructural proteins of the SARS-CoV-2 virus (13 peptides) and a 15-mer epitope of CD4⁺ T lymphocytes, from the S-protein, based on the analysis of publications on genome-wide immunoinformatic analysis of T-cell epitopes of the virus (Wuhan strain), as well as a number of clinical studies of immunodominant epitopes among patients recovering from COVID-19 disease. The peptides were synthesized and five compositions of 6–7 peptides were included in liposomes from egg phosphatidylcholine and cholesterol (~200 nm size) obtained by extrusion. After double subcutaneous immunization of conventional mice, activation of cellular immunity was assessed by the level of cytokine synthesis by splenocytes in vitro in response to stimulation with relevant peptide compositions. Liposomal formulation exhibiting the best result in terms of the formation of specific cellular immunity in response to vaccination was selected for further experiments. Evaluation of the protective efficacy of this formulation in an infectious mouse model showed a positive trend in the frequency of occurrence of hyaline-like membranes in the lumen of the alveoli, as well as a somewhat lower severity of microcirculatory disorders. The latter circumstance can potentially help reduce the severity of the disease and prevent its adverse outcomes. A method to produce liposome preparations with peptide compositions for long-term storage is under development.

Myocardial infarction versus COVID-19 blood secretome

Background

Both myocardial infarction (MI) and COVID-19 are characterized by cytokine storm in blood.

Purpose

The objective of this study was to compare the concentration of 39 cytokines, chemokines, and growth factors in blood sera of patients with MI, COVID-19 (COV), and healthy donors.

Methods

Patients' blood was collected within 1–2 days after hospitalization in the cardiovascular or COVID intensive care units. All COV patients were in a severe condition; all had increased C reactive protein, 86 and 95% had increased ferritin and D-dimers levels accordingly, 8–10 times decreased lymphocyte numbers. The analysis of the humoral factors in blood serum of MI (n=22), COV (n=23) and donors (n=27) was performed using a 39-plex cytometric analysis.

Results

Among all factors analyzed TGFa, IL-1b, 2, 3, 5, 9, 13, 17A were almost not detectable both in patient and donor sera. The concentrations of the other 31 humoral factors in normal sera differed significantly from 0 to 22000 pg/mL. We divided them into house-keeping factors HKF ranged from 1000 to 22000 pg/mL; sentinel innate immunity factors SIF (30–200 pg/mL), and acute phase factors APF (0–30 pg/mL). HKF were detected in all samples. Among SIF and APF IL-1a, G-CSF, IFNa2, IL-7, MIP-1a, IL-12, and IFNg were detected in 56–80% donor blood while IL-1RA, MCP-3, IL-2, 6, 10, 12, 15, FLT-3F, GM-CSF, TNF-b – only in 10–55%. At the same time all MI patients were 100% positive in all these factors showing extensive activation of blood secretome. Among low incidence APF cytokines in COV patients, percentage of IL-1RA, MCP-3, IFNa2, IL-6, 10, 15, FLT-3L negative sera decreased 3–5 times; and all sera were positive for MIP-1a and IL-12. At the same time TNF-a level decreased significantly from 0 in control to 85% of negative sera in COV patients. Summarized results are shown as the ratios of factor concentrations in MI or COV sera to normal control (Fig). Blood secretome of MI changed more significantly than of COV patients. The major factors (shown in red) in MI were IL-6, IL-12, IFNg, FLT-3L, GM-CSF, and IL-15, which increased 12, 9, 6, 6, 6, and 5 times accordingly. In COV sera IL-6, IL-10, IP-10, and MCP-3 increased by 28, 12, 10, and 9 times accordingly. Less expressed however significant increases are marked with asterisks.

Conclusions

Acute MI is characterized by severe disturbances in blood secretome with an increased level of 25 out of 39 factors studied. Contrary to it, in COV patients the levels of IL-6, 10, IP-10, and MCP-3 were more enhanced while only 15 out of 31 exceeded normal levels.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Public Institution

Fusion with an albumin-binding domain improves pharmacokinetics of an αvβ3-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 αvβ3-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.

Humoral response to Epstein-Barr viral infection in patients with allergies

Type I hypersensitivity is mediated by the production of IgE antibodies in response to normally harmless substances. Debate still continues about the mechanisms underlying allergic reactions. Reduced barrier tissue function can be one of the risk factors for allergies. The aim of the present work was to compare the humoral immune response to Epstein-Barr virus in patients allergic to the A. alternata fungus or D. farinae house dust mites and healthy donors. It is known that up to 90% of the world population are infected with EBV. This infection occurs at early age when a child develops allergy. The antibodies were analyzed using immuno-PCR and the recombinant EBV protein rEBNA. We were able to demonstrate that infection occurs at early age in both allergic patients and healthy donors. The proportion of EBP-seropositive individuals was comparable between the groups (75% and 74%). The proportion of patients with high IgG1 titers among patients with allergies was lower (7%) than in healthy donors (18%), suggesting a lower viral load. In patients with allergies (but not in healthy donors) IgG1 titers declined as children grew older (р = 0.037). Besides, IgA1 titers were increased in patients with allergies in comparison with healthy donors, but differed between patients allergic to A. alternata and house dust mites. In allergic individuals, production of IgM against EBV was triggered earlier than in healthy donors. We conclude that IgM production and the IgA1-mediated humoral response occur earlier in patients with allergies, causing a decline in IgG1 titers over time.

Myths, reality and future of mesenchymal stem cell therapy

Mesenchymal stem cell (MSC) therapy represents an alternative approach for tissue regeneration and inflammation control. In spite of a huge amount of preclinical data that has been accumulated on the therapeutic properties of MSCs, there are many conflicting results, possibly due to differences in the properties of MSCs obtained from different sources or underestimated mechanisms of MSC in vivo behavior. This review consolidates the in vivo effects of MSC therapy, discusses the fate of MSCs after intravascular and local delivery and proposes possible trends in MSC therapy.

[Immuno-PCR Assay for Quantitation of Antibodies to Epstein-Barr Virus]

Successful disease prevention and therapy critically depend on timely diagnosis of infections. Quantitative immuno-PCR (qiPCR) technology improves the sensitivity in the detection of antibodies to pathogens. A qiPCR-based assay was developed to determine IgG antibodies to Epstein-Barr virus (EBV) in the human blood serum. EBV nuclear protein 1 fragment (pEBV) was expressed in Escherichia coli. A synthetic single-stranded deoxyribonucleotide was conjugated to streptavidin, and the conjugate was used to detect рEBV-IgG1-biotin complexes by qiPCR. The IgG1 titers determined by qiPCR were compared to the results of enzyme-linked immunosorbent assay (ELISA). The sensitivity of qiPCR was one order of magnitude higher than that of ELISA. Thus, a highly sensitive qiPCR-based assay was developed to quantitate antibodies specific to the recombinant EBV antigen.

Cytokine Production in Mixed Cultures of Mesenchymal Stromal Cells from Wharton's Jelly and Peripheral Blood Lymphocytes

We compared the production of 19 humoral factors in mixed cultures of mesenchymal stromal cells from Wharton's jelly and allogenic peripheral blood lymphocytes. For evaluation of the specificity of immunosuppressive activity of mesenchymal stromal cells, comparative analysis of the production of these humoral factors in mixed cultures of lymphocytes and epithelial BxPC-3 cells was conducted. The production of soluble factors in both mono- and mixed cultures significantly correlated (p<0.05). The maximum production was found for proinflammatory chemokine IP-10 and IFN-γ and anti-inflammatory cytokine IL-10. The major difference of mesenchymal stromal cells from epithelial BxPC-3 cells was 7-fold higher production of IL-10, which can explain the immunosuppressive effect of mesenchymal stromal cells.

Interaction of Lymphocytes with Mesenchymal Stem Cells

We studied the interaction of neural stem cells and dental pulp-derived mesenchymal stem cells with lymphocytes from autologous and heterologous donors. Flow cytometry analysis with the use of CFSE-labeled lymphocytes demonstrated an increase in the content of proliferating CD8, CD16 and CD56 cells, but not CD4 cells in cultures of HLA-DR-negative mesenchymal stromal cells from the dental pulp co-cultured with lymphocytes. In neural cultures expressing HLA-DR, all subpopulations of T cells and NK cells were activated. No differences between the autologous and heterologous cultures were revealed.

Intracellular sorting of differently charged chitosan derivatives and chitosan-based nanoparticles

Chitosan (Chi) is a biodegradable nontoxic polycation with multiple reactive groups that is easily used to obtain derivatives with a desired charge and hydrophobic properties. The aim of this work was to study the intracellular traffic of positively charged hexanoyl-chitosan (HC) or HC-based nanoparticles (HCNPs) and negatively charged succinoyl-chitosan (SC) and SCNPs in epithelial and macrophage cell lines. By using flow cytometry we demonstrated that positively charged HC adhered to cell membranes quicker and more efficiently than negatively charged SC or NPs. However confocal studies showed that SC and SCNPs penetrated cells much more efficiently than HC while HCNPs did not enter the epithelial cells. Macrophages also phagocyted better negatively charged material but were able to engulf both HC and HCNPs. Upon entering the cells, SC and SCNPs were co-localized with endosomes and lysosomes while HC was found in mitochondria and, to a lesser extent, in lysosomes of epithelial cells. Macrophages, RAW264.7, more efficiently transported all Chi samples to the lysosomal compartment while some positively charged material was still found in mitochondria. Incubation of Chi derivatives and ChiNPs at pH specific to mitochondria (8.0) and lysosomes (4.5) demonstrated the neutralization of Chi charge. We concluded that epithelial cells and, to a lesser extent, macrophages sort charged material to the organelles neutralizing Chi charge.

Expression of duodenase-like protein in epitheliocytes of Brunner's glands in human duodenal mucosa

A duodenase, a protease structurally related to human cathepsin G, was found earlier in bovine duodenal mucosa. It was demonstrated that under the influence of duodenase an enteropeptidase zymogen is activated in vitro showing the possible participation of duodenase in the cascade of activation of digestive enzymes. To identify a duodenase functional analog in human duodenum, an immunofluorescence study of duodenal mucosa was conducted by confocal microscopy using antibodies to human cathepsin G and to bovine duodenase. The previously unknown place of synthesis and secretion of cathepsin G - Paneth cells located at the bottom of Lieberkuhn crypts - was revealed. Binding of cathepsin G-specific antibodies in a rough endoplasmic reticulum zone and in the cryptal duct was observed. Duodenase-specific immunofluorescence but not that of cathepsin G was found in the epitheliocytes and secretory ducts of Brunner's glands, which are characteristic sites of duodenase biosynthesis in cattle. Binding of CD14-specific antibodies in the Brunner's glands, where the antibodies co-localized with the antibodies to duodenase, was also demonstrated. These data indicate the presence of a protein immunologically similar to duodenase in the human duodenal mucosa. Our study demonstrated the absence of its co-localization with cathepsin G in Brunner's glands.

Lipophilic prodrugs of a triazole-containing colchicine analogue in liposomes: biological effects on human tumor cells

Colchicine site binders--blockers of tubulin polymerization--are potential antimitotic agents for anticancer therapy. To reduce their systemic toxicity and improve biodistribution, encapsulation in nanosized liposomes may be employed. Liposomes present a convenient means for preparation of injectable formulations of hydrophobic compounds, however colchicine as such is known to leak through the lipid bilayer. In this study, newly synthesized triazole-containing analogues of colchicine and allocolchicine, and their palmitic and oleic esters (lipophilic prodrugs) were tested for anti-proliferative activity and apoptosis-inducing potential. In contrast to colchicine conjugates, whose activities ranged with those of colchicine, allocolchicine derivatives exhibited drastically lower effects and were discarded. Liposomes of about 100 nm in diameter composed of egg phosphatidylcholine--yeast phosphatidylinositol--palmitic or oleic prodrug, 8 : 1: 1, by mol, were prepared by standard extrusion technique and tested in a panel of four human tumor cell lines. Liposome formulations preserved the biological activities of the parent colchicinoid the most towards human epithelial tumor cells. Moreover, liposomal form of the oleoyl bearing colchicinoid inhibited cell proliferation more efficiently than free lipophilic prodrug. Due to substantial loading capacity of the liposomes, the dispersions contain sufficient concentration of the active agent to test wide dose range in experiments on systemic administration to animals.

The p1 protein of the yeast transposon Ty1 can be used for the construction of bi-functional virus-like particles

Virus-like particles (VLPs) containing heterologous proteins are often used as vaccines. Two approaches for the construction of bi-functional VLPs using hybrid protein pl-380 of the TY1 transposon of Saccharomyces yeast are described. We have shown that both C- and N-termini of p1-380 can be used for the expression of heterologous peptides. Peptides from A. Fumigatus Asp f 2, expressed at the C- and/or N-termini of p1-380, did not interfere with VLP self-assembling, were accessible for antibodies and hence were exposed at the VLP surface. Another way to obtain bivalent VLPs is the formation of mixed particles, which co-express two hybrid pl proteins with different heterologous protein fragments at the C-terminus. To do it the yeast cells were transfected with a mixture of two recombinant DNA coding Asp f 2 peptide and green fluorescent protein (Gfp). We have shown that both Asp f 2 peptide and Gfp are expressed within the same particle. To evaluate biological activity of bi-functional VLP a construction containing peptides representing dominant T- and B-cell epitopes of Asp f 2 was produced. Bi-functional particles were more potent in stimulating memory immune responses. These results demonstrate new possibilities of pl-380 based expression system to produce multifunctional VLPs.

Immunotherapy of allergic bronchopulmonary aspergillosis: a clinical and experimental approach

Allergic bronchopulmonary aspergillosis (ABPA) is a severe allergic pulmonary complication caused by the saprophytic fungus Aspergillus fumigatus. The present review examines the pathogenesis of this disease describing in detail the role of innate and acquired immunity in the induction of sensitivity to A.fumigatus. Different approaches in developing specific immunotherapeutic treatments such as induction of anergy, regulatory cells, a switch from Th2 to Th1 type of immune response, CpG and genetic immunization and the usage of altered peptides or modified allergens are critically examined.

Immune response modulation by recombinant peptides expressed in virus-like particles

Aspergillus fumigatus, a ubiquitous fungus, is implicated in the pathogenesis of a number of clinically different allergic diseases in man, including allergic bronchopulmonary aspergillosis. Peptide-based immunotherapy may offer an alternative treatment strategy for the management of allergic disease. The objective of this study was to alter the allergen-specific immune response using dominant T cell epitopes of a major A. fumigatus allergen, Asp f2, expressed in yeast as virus-like particles (VLP). The T cell epitopes of Asp f2, recognized in mice with an H-2d background, were determined by producing T-cell hybridomas. Two dominant T cell epitopes, aa60--71 and aa235--249, were identified and expressed in a yeast VLP system. To induce tolerance VLP-peptides were injected subcutaneously into mice previously immunized with recombinant Asp f2. The T cell immune response was abrogated totally in 3 weeks following a single injection of VLP but was restored 2 months later following intranasal antigen exposure. T-cell depletion resulted in the reduction of 20-30% of all antigen-specific immunoglobulin classes. Thus, recombinant peptides expressed in the VLP system can be used successfully in the modulation of Asp f2-induced immune response in mice, although a single administration is not sufficient to maintain a state of tolerance for a long period of time.

Do T helpers 1 and 2 recognize different class II MHC molecules? Humoral and cellular immune responses to soluble allergen from Aspergillus fumigatus Asp f2

Cellular signals leading to T helper (Th)1/Th2 shift are not well known. Here we demonstrate that Th1 possibly recognizes peptides presented by the IE molecule of MHC class II while Th2 is activated by the recognition of peptides presented by the IA molecule. BALB/c mice immunized with Asp f2 developed stable IA-restricted Th2 immune response to the 12th day after immunization, as analyzed by IL-2 production. On the contrary, early Th0 cells did not secrete IL-2 upon Asp f2 stimulation but did produce a high level of IL-2 if stimulated in the presence of anti-IA Abs. This effect of anti-IA Abs on early Th0 cells was both MHC IE and CD4(+) cell restricted. In vivo blocking of Asp f2 peptide presentation by the IA molecule led to the formation of antigen-specific cytotoxicity as demonstrated using immune splenocytes as effector cells and Asp f2 loaded P815 cells as targets.

Cellular localization of the galactose-binding lectin from human serum

An SL2 lectin was isolated from human serum and characterized previously; cellular localization of the lectin was studied using polyclonal rabbit antibodies. According to cytofluorimetry, anti-SL2 antibodies bound only to lymphocytes and monocytes but not to other blood cells. Antibodies bound to Jurkat T cell lymphoma but did not interact with IM-9 cells of B cell origin. Moreover, the Jurkat cells bound oligosaccharides having the highest affinity to SL2 (GalNAcalpha_and Fucalpha1-2Gal), and this interaction was inhibited by anti-SL2 antibodies. Lysis of the Jurkat cells with subsequent electrophoresis and Western blotting indicates that anti-SL2 antibodies recognized a 14-kD protein.

Immunostimulatory activity of Milife, a novel immunomodulator of fungus origin

Milife is a novel immunomodulator derived from the fungus Fusarium Sambucium. In this study we examined immunomodulatory properties of Milife in 10 months-old BLRB mice. Milife was given to mice orally in a daily dose of 1 mg per mouse, for 2 to 6 days. Groups of mice were sacrificed on days 2, 4, and 6 of treatment, and 3 weeks after completion of a 6 days treatment with Milife, and lymphoid organs were obtained for analysis. Milife administration led to rapid and significant increase in total leukocyte and lymphocyte numbers in peripheral blood that persisted for at least 3 weeks after a 6 days treatment. Cellularity of lymph nodes, bone marrow and thymus increased significantly at days 4 and 6 of treatment, but returned to pretreatment levels after Milife discontinuation. Though total splenocyte numbers did not change dramatically, there occurred delayed increase in CD4+ cells in the spleen 3 weeks following treatment. Preferential accumulation of CD4+ cells was also consistently found in peripheral blood, with the peak being observed at day 6 of treatment. As a result, CD4/CD8 ratio in blood and spleen was significantly higher in treated than in untreated mice. Splenocytes from treated mice proliferated more vigorously in response to Con A. When added in vitro, Milife also mildly costimulated Con A-induced proliferation of splenocytes from intact animals. In conclusion, we have found that Milife can stimulate leuko- and lymphopoesis in BLRB mice, in particular, accumulation of CD4+ T cells in peripheral lymphoid organs. We conclude that Milife may represent an immunomodulator with the potential to correct T cell dysfunction in patients with immunodeficiency.

Influence of Myelopeptides on IL-1 and IL-2 Activities

Myelopeptides are immunoregulatory molecules originally isolated from porcine bone marrow cell culture. The influence of synthetic analogous of these peptides on IL-1 and IL-2 activities was studied. Myelopeptide-1 but not myelopeptide-2 replaced IL-1 activity in a test of costimulation of thymocyte proliferation in the presence of mitogen. Conversely, myelopeptide-2, but not myelopeptide-1, stimulated both production of IL-2 by murine splenocytes and IL-2-dependent proliferation of CTLL-2 cell line. The enhancing effect of myelopeptide-2 on IL-2-associated processes was the most pronounced at the early stages of cell activation. The resting T cells stimulated with suboptimum doses of concanavalin A and activated T cells, expressing low level of IL-2R, were sensitive to myelopeptide-2 action. The possible role of myelopeptides in differentiation of T0 helper into T1 helper and T2 helper is discussed.

Quantitative analysis of interleukin-2-induced proliferation in the presence of inhibitors using a mathematical model

The proliferative response of CTLL-2 cells to human recombinant interleukin-2 (IL-2) can be modeled mathematically using enzyme kinetic equations. This approach has been used to analyze dose-response curves (IL-2 concentration vs. level of proliferation) measured by MTT and [3H]TdR assays. The values of functional dissociation constants, equivalent to IL-2 concentrations giving 50% of the maximal response, depended on the cell concentration and increased from 4 to 60 pM for the [3H]TdR assay and from 40 to 140 pM for the MTT assay when the cell concentration was increased from 2 x 10(3) to 4 x 10(4) cells/well. The types of inhibition and dissociation constants for various inhibitors of IL-2-dependent proliferation such as mAbs against IL-2 receptor (7D4 and AMT13) and normal mouse serum (NMS) were also analyzed. Both mAbs exhibited competitive mechanisms of inhibition whereas NMS inhibited IL-2-driven proliferation in a mixed manner. Two gel-filtration fractions of NMS with inhibitory activity manifested different types of inhibition: purely competitive type of inhibition in the case of a 10-15 kDa fraction and a mixed type of inhibition for a 100-150 kDa fraction. The proposed model can also be used for quantitative analysis of the influence of various factors (pH, temperature, cultivation condition) on the level of proliferation.

Muramyl dipeptide-induced changes in murine splenocyte responses to concanavalin A

The effect of muramyl dipeptide (MDP) on Con A-stimulated activation of murine spleen cells was studied. MDP was found to enhance or suppress the proliferative response of splenocytes when different concentrations of Con A were used. MDP was shown to change the IL-2 content in culture supernatants of stimulated cells and to influence IL-2-dependent proliferation of Con A-blasts. A high degree of correlation was found between the proliferation of Con A-blasts and the expression of IL-2 receptors on Con A-blasts. This correlation, however, disappeared in the presence of MDP. The effects of MDP were shown to depend on the level of initial cell activity or rather on conditions leading to a given initial activity of cells.