Experience with pandemics strongly suggests that vaccination of the population in all categories should be a national priority. The choice of a vaccine production platform should be made in such a way as to achieve an optimal effect at the lowest possible cost. A peptide vaccine or a protein platform vaccine could serve these purposes. Oral and intranasal vaccines are also attractive due to the ease of administration to different population groups, and the resulting immunity is not inferior to that of intramuscularly administered vaccines.In this work, synthetic peptides representing the fragments of the surface protein SARS-CoV-2 were investigated. The peptides were prepared by classical peptide synthesis, with peptide No. 1 (Lys-Ile-Ala-Asp-Tyr-Asn-Tyr-Lys-Leu) being immunodominant for the HLA-A02:01 phenotype with a low calculated concentration of half-maximum inhibition. Peptide No. 2 (Val-Arg-Gln-Ala-Pro-Asn-Gly-Gln-Thr) was chosen as control and is not immunodominant for the HLA-A02:01 phenotype, with a high estimated concentration of half-maximum inhibition (IC50).80 persons were questionnaired and 78 volunteers were examined. Cellular immunity parameters were analyzed using a Cytomics FC 500 flow cytometer and gamma interferon (IFN-γ) was determined by ELISA. The results were processed using Statistica 10 software. As a result, a new method was tested to evaluate the activation of blood leukocytes by synthetic peptides. Regardless of the HLA-A phenotype of the study subjects, the peptides were able to bind to leukocytes, indicating a universal response to foreign peptides, especially to innate immune cells. Peptide No. 2 with high calculated IC50, compared to peptide No. 1 with low calculated IC50, showed significantly higher binding to lymphocytes and monocytes and activation of basophils. The peptides used in this work showed that they interact with leukocytes, activating them through the secretion of IFN-γ. Thus, our work demonstrates an approach to creating a peptide vaccine in the in vitro research phase, as well as to studying the antiviral response by the IFN-γ growth in response to the peptides.

In experiments on male Wistar rats, the effect of synthetic derivatives of arginine-vasopressin (tetrapeptides N-Ac-DSer-Pro-DArg-Gly-NH2 (I) (1.0 μg/kg, i. n.), N-Ac-Trp -Pro-Arg-Gly-NH2 (II) (1.0 μg/kg, i. n.) on the dynamics of the level of anxiety (LA) and the ability to reproduce operant reactions (OR) against the background of 24-hour deprivation of the paradoxical phase of sleep (REM sleep deprivation) in rats. Statistically, N-Ac-Trp-Pro-Arg-Gly-NH2 significantly ( p < 0.05) reduced the LA of rats exposed to stress, increasing the proportion of individuals in the population that had spent time in the central square of the actometer chamber not less than 10 % of the total duration of actometry. The oligopeptide N-Ac-DSer-Pro-DArg-Gly-NH2 had a statistically significant ( p < 0.05) corrective effect on the ability to reproduce the developed OR of pressing the pedal in rodents (Wistar rats of an unranked population and Wistar individuals with low LA) subjected to REM sleep deprivation. Thus, both studied compounds did not cause cognitive impairment, and N-Ac-DSer-ProDArg-Gly-NH2 improved mnestic functions against the background of REM sleep deprivation. The results of assessing the level of general motor activity indicated the absence of side sedative effects in I (1.0 μg/kg) and II (1.0 μg/kg ‒ at a dose that causes an anxiolytic effect when administered II). The data obtained indicate the anxiolytic effect of N-Ac-Trp-Pro-Arg-GlyNH2, the positive mnemotropic effect of N-Ac-DSer-Pro-DArg-Gly-NH2, and a low likelihood of developing side effects in relation to the central nervous system against the background their applications.

Синтетический аналог C-концевого фрагмента фрагмента аргинин-вазопрессина АВП(6-9) — Ac-D-MPRG при хроническом интраназальном введении в дозах 0,01, 1 и 10 мкг/кг с 3 по 7 сут жизни стимулирует выработку условной реакции активного избегания животных всех исследуемых возрастов: препубертатного (35 – 39 сут жизни); пубертатного (49 – 53 сут жизни); взрослых половозрелых животных (63 – 67 сут жизни). Показано, что эффективность Ac-D-MPRG зависит от дозы. Так, Ac-D-MPRG в дозе 0,01 мкг/кг обладает более выраженным эффектом у животных в препубертатном периоде в среднем на 74 % (p ≤ 0,024), по сравнению с контрольной группой животных, а в дозах 1 и 10 мкг/кг — в среднем на 47 и 61 %, соответственно (p ≤ 0,04) в пубертатном периоде и у взрослых животных, по сравнению с контролем. Аргинин-вазопрессин влияет на способность к обучению только у взрослых животных в среднем на 15 – 27 % (p ≤ 0,05), по сравнению с группой интактного контроля. Ac-D-MPRG в дозах 1 и 10 мкг/кг оказался эффективнее в среднем на 8 – 12 % (p ≤ 0,05), чем аргинин-вазопрессин в дозах 1 и 10 мкг/кг, при выработке навыка с отрицательным подкреплением. Полученные данные демонстрируют широкий спектр ноотропных эффектов пептида Ac-D-MPRG.

The effect of proline-containing oligopeptides N-Ac-DSer-Pro-DArg-Gly-NH 2 (B-4), N-Ac-Trp-Pro-Arg-Gly-NH 2 (B-5), N-Ac-Tyr-Pro-Arg-Gly-NH 2 (B-7), and Pro-Gly on the behavior of male ICR mice in the Forced Swim Test was studied. N-Ac-DSer-Pro-DArg-Gly-NH 2 (1.0 mcg/kg, i.n) increased the intensity of active swimming, most pronounced – during the last 2 minutes of testing (maximum fatigue period), i.e., it prevented the behavior of “despair”.

RuIn this work, it was found that Ac-D-MPRG, a tetrapeptide synthesized on the basis of the C-terminal fragment of arginine-vasopressin(6-9), upon chronic neonatal administration, a ects anxiety and exploratory behavior in rats of three age groups. The most signi cant effect of the peptide was manifested under more stressful conditions. The rats of the experimental group showed less anxiety. They did less grooming in the Elevated Plus Maze test and increased time in light in the Light-Dark Chamber test. Motor activity changed from passive holding in the prepubertal period to active avoidance in puberty and adulthood. Based on the data obtained, we conclude that the effects of the peptide are manifested only when exposed to a biologically signi cant stimulus.

A search for novel antidepressant analogs of arginine-vasopressin (AVP) by a computer modeling revealed the following peptide analogs of the C-terminal part of AVP: N-Ac-D-Ser-Pro-D-Arg-Gly-NH2, N-Ac-Phe-Pro-Arg-Gly-NH2, and N-Ac-Trp-Pro-Arg-Gly-NH2. Syntheses of the modeled compounds were described in this article. The compounds that could potentially exhibit the antidepressant activity were examined in the forced swimming test. N-Ac-Trp-Pro-Arg-Gly-NH2 (0.1, 1.0, and 10.0 µg/kg) and N-Ac-D-Ser-Pro-D-Arg-Gly-NH2 (1.0 µg/kg) were shown to have the highest similarity to the fluoxetine reference antidepressant according to a number of parameters after the intranasal administration to the Wistar male rats.

The article presents the synthesis and results of the study of the effect of chronic neonatal administration by intranasal method of an analogue of the C-terminal fragment of arginine-vasopressin (AVP) - N-Ac-DMet-Pro-Arg-Gly-NH2 on the training and level of depression in white rats of three age groups. It is shown that the most significant effect of the analogue was manifested in the test for the development of conditional reaction of active avoidance. A favorable effect on the degree of depression of animals is also well expressed. According to the data obtained, we conclude that the action of the peptide is manifested only under the influence of a biologically significant stimulus.

— It is known that the Arg-Gly-Asp sequence in the fibrinogen molecule is key in binding to the receptors on the surface of platelets. We searched for the compounds which were able to inhibit the binding and synthesized the following analogs of this sequence: 2-acetoxybenzoyl-Arg - βAla-Asp, 4-piperidinecarbonyl-βAla-Asp, and 4-aminobezoyl-βAla-Asp. These compounds were shown to inhibit the platelets aggregation in a different degree. The 2-acetoxybenzoyl-Arg-βAla-Asp analog demonstrated the highest inhibitory activity. A decrease in the expression of the CD62p and CD63 markers on platelets was also found after the action of the Arg-Gly-Asp analogs, confirming the ability of these compounds to block the fibrinogen binding sites for the GP IIb/IIIa glycoprotein receptors.

Biospecific sorbents for the removal of IgG and subclasses from biological fluids based on oligopeptides that contain aromatic protein residues have been created. A functional assessment of high-quality experimental samples of sorbents and their preferences for IgG subclasses was carried out. It was found that each sorbent has good characteristics for removing IgG from biological fluids, but the sorbent based on Phe-Trp-DTyr is more effective in binding of total IgG. With respect to IgG subclasses, the best binding results are as follows: Phe-Gln-Tyr-OMe - IgG1 (86,53%), Phe-Ala-Tyr - IgG2 (60,2%), Phe-Trp-DTyr - IgG3 (59,52%) and IgG4 (55,05%).

Molecular modeling, which identified several peptide sequences, was carried out in search for compounds capable of reducing the interleukin-8 concentration in human blood plasma. The replacement of the glutamic acid residue in the Glu-His-OMe and Glu-His-Trp-OMe compounds by its cyclic form, as well as the introduction of the DTyr and DAla residues into the sequence Asp-Tyr-Ala-Pro, was shown to double their ability to bind interleukin-8.

Hyperproduction of immunoglobulin G (IgG) is a major pathogenic factor in autoimmune diseases. Specific sorbents are used to eliminate the high level of IgG. Molecular docking can be used as a tool for theoretical search for sorbent ligands for the IgG removal from biological fluids. Using docking, modeling of amino acid interactions with IgG ligands was performed. Based on the docking results, active amino acids were identified and possible combinations of them were proposed for the creation of diand tripeptide sequences. As a result, aromatic amino acids (Tyr, Trp, Phe), di-and tripeptides based on them (Trp-DTyr, Phe-DTyr, Trp-Phe-DTyr, Phe-Trp-DTyr) were found to have high activity for IgG proteins, and three peptides (Trp-Phe-DTyr, Phe-Trp-DTyr) not only show high activity to total IgG, but can also be divided in their activity relative to subclasses of class G immunoglobulins.

By dynamic experiments, the purpose of which was to establish the time during which the saturation of sorbents occurs, as well as the maximum amount of total IgG bound, the saturation and capacity properties were revealed. Sorption dynamics data have been obtained for tripeptides: Phe-Trp-DTyr, Trp-Phe-DTyr, Phe-Ala-Tyr-OMe, Phe-Asn-Tyr-OMe, Phe-Asp (Bzl)-Tyr-OMe, Phe-Gln-Tyr-OMe and Phe-Gly-Tyr. Specific saturation was reliably confirmed for the Phe-Trp-DTyr sample and the Phe-Gln-Tyr-OMe sample. Other samples of sorbents show positive dynamics with episodic periods of desorption, with further alignment of the positive dynamics of the sorption process.

Over the past decades, molecular docking has become an increasingly popular tool for the development of new drugs. To search and design new compounds, a detailed study of the interaction of existing complexes of ligands with the target protein is necessary. According to the purpose to identify amino acid residues of the B domain of protein A of Staphylococcus aureus involved in interaction with immunoglobulins G, we studied the interaction mechanisms during the formation of a complex of protein A of the Staphylococcus aureus cell wall and immunoglobulins G by molecular docking. By the means of molecular docking we selected four amino acid residues of Phe132, Gln129, Tyr133 and Phe124, which we can use to construct a peptide analog of the active binding site of protein A with the Fc fragment of immunoglobulins G. The obtained results can serve as starting point for an effective strategy for finding new medicines, in particular, they can be used to further develop biospecific sorbent for the selective removal of immunoglobulins G from human blood.

Binding of interleukin-6 (IL-6) is the perspective target for the anti-inflammatory therapy in many pathological conditions (sepsis, autoimmune pathology, allergic diseases). The aim of this work was to develop and study the binding IL-6 oligopeptides. To achieve the goal, were set and successfully solved the following tasks: studying three-dimensional models of molecular structures of IL-6 incombination with the R-IL-6 and gp130, prediction and virtual synthesis low molecular weight oligopeptides; evaluating the free energy of IL-6 binding for identity the most effective oligopeptide; studying the changing the concentration of IL-6 inthe model solution after contact with experimental oligopeptides. In the article presents the binding IL-6 energy of 62 peptides, designed using the PyMol. Energy was calculated in the Chimera program using the AutodockVina application. There are also presented results of in vitro experiments interacting 7 sextapeptides, 2 tetrapeptides, and 3 tripeptides with recombinant IL-6. The effectiveness of the peptides was calculated by reducing the concentration of cytokine in solution as a percentage of the initial concentration.The free binding energy has shown that the efficiency of binding increases with an increase in the total number of amino acids and, in particular, of aromatic amino acids in the oligopeptide. Correlation analysis showed that the molecular modeling method is not absolutely effective for predicting the structure of an oligopeptide, however, it can be used as one of the preliminary steps for analyzing the interaction between molecules and studying the optimal interaction points. Two oligopeptides were identified as the most promising for further synthesis as the ligands for binding and evaluating IL-6 inhuman blood plasma.

Using methods of theoretical conformational analysis, the Phe-Gln-Phe-Tyr-OMe tetrapeptide has been designed and synthesized. Amino acid fragments of this tetrapeptide are present in the active center of protein A, providing its binding with the Fc-fragment of human IgG antibodies. Activity of this tetrapeptide has been confirmed by studies of its binding affinity with Fc-fragment of human IgG antibodies.

Since several different pathways are involved in cerebral ischemia/reperfusion injury, combination therapy rather than monotherapy may be required for efficient neuroprotection. In this study, we examined the protective effects of an apoptosis inhibitor Gly14-humanin (HNG) and a necroptosis inhibitor necrostatin-1 (Nec-1) on hypoxia/ischemia/reperfusion injury. Cultured mouse primary cortical neurons were incubated with Nec-1, HNG or both in a hypoxia chamber for 60 min. Cell viability was determined by MTS assay at 24 h after oxygen-glucose deprivation (OGD) treatment. Mice underwent middle cerebral artery occlusion for 75 min followed by 24 h reperfusion. Mice were administered HNG and/or Nec-1 (i.c.v.) at 4 h after reperfusion. Neurological deficits were evaluated and the cerebral infarct volume was determined by TTC staining. Nec-1 or HNG alone had protective effects on OGD-induced cell death. Combined treatment with Nec-1 and HNG resulted in more neuroprotection than Nec-1 or HNG alone. Treatment with HNG or Nec-1 reduced cerebral infarct volume from 59.3 ± 2.6% to 47.0 ± 2.3% and 47.1 ± 1.5%, respectively. Combined treatment with HNG and Nec-1 improved neurological scores and decreased infarct volume to 38.6 ± 1.5%. In summary, we demonstrated that the combination treatment of HNG and Nec-1 conferred synergistic neuroprotection on hypoxia/ischemia/reperfusion injury in vitro and in vivo. These findings provide a novel therapeutic strategy for the treatment of stroke by combining anti-apoptosis and anti-necroptosis therapy.