Synthesis of Deuterium-Labeled Pyrrolylcarnosine

The effect of temperature on the effectiveness of the incorporation of deuterium into pyrrolylcarnosine (PC) was studied. Deuterium gas and heavy water were used as a source of deuterium. Isotope exchange was carried out using solid-phase and liquid-phase methods. It was found that it is better to use isotope exchange with deuterated water to obtain preparative amounts of labeled pyrrolylcarnosine. When using y solid-phase method, the main label is in pyrrole. The incorporation of deuterium at a higher temperature occurs more evenly. In addition, the use of deuterated water made it possible to reduce the amount of unlabeled isotopomer to almost 0% and to obtain a product with a yield of 70% and a content of more than seven deuterium atoms. It was established that the content of deuterium in the compound can be increased by pretreating the reaction mixture with deuterium gas. This approach opens up additional opportunities for the synthesis of labeled compounds.

Participation of Nitric Oxide in the Realization of Hemostatic Effects of Glyproline Peptides

The involvement of nitric oxide in the responses of the hemostasis system to the appearance of proline-containing peptides in the blood was studied in experiments on rats. It was shown that a single intranasal administration of peptides PGP, RPGP, and PGPL to rats led to an increase in fibrinolytic, anticoagulant, and antiplatelet potential of blood. The use of the non-selective NO-synthase blocker L-NAME almost completely inhibited the anticoagulant effects of the glyprolines. It was found that the mechanism of the anticoagulant-fibrinolytic and antiplatelet action of glyproline peptides is determined by the activation of the enzymatic pathway of nitric oxide formation. The obtained results revealed the involvement of nitric oxide in the implementation of hemostatic and vascular-endothelial functions of the organism.

Influence of Semax on the Level of Pro- and Anti-Inflammatory Cytokines in Conditions of "Social" Stress

Introduction:

This study was devoted to the experimental study of the effect of Semax (Met-Glu-His-Phe-Pro-Gly-Pro) on the level of pro- and anti-inflammatory cytokines (IL-1β, IL-4, IL-6, TNF-α, TGF-β1) in conditions of "social" stress

Aim of the study:

to study the effect of Semax on the level of pro- and anti-inflammatory cytokines (IL-1β, IL-4, IL-6, TNF-α, TGF-β1) under conditions of “social” stress.

Materials and methods:

White nonlinear rats (males, 6–8 months of age) were used as experimental animals. The animals were divided into groups: 1 – the control group (n=10); 2 – animals exposed to "social" stress (20 days) (n=10 aggressors/10 victims); 3 – rats exposed to "social" stress and receiving Semax intraperitoneally at a dose of 100 μg / kg / day (20 days) (n=10 aggressors/10 victims). Sensory contact was chosen as an experimental model of "social" stress. The level of cytokines (IL-1β, IL-4, IL-6, TNF-α, TGF-β1) was determined by the method of enzyme-linked immunosorbent assay.

Results:

Currently, within the framework of the development of a direction to study the functioning of the unified cytokine network of the body, there is a need for a detailed analysis of changes in the production of individual cytokines during various pathophysiological reactions, including stressful effects. The experimental "social" stress is accompanied by an increase in the production of IL-1β, IL-6, TNF-α, TGF-β1, which allowed us to consider stress as the main inducer of the production of cytokines of the family of proinflammatory interleukins and various growth factors. It was previously thought that inflammation and the immune response are the only factors capable of causing the production of most cytokines. In recent years, scientific works have appeared in which stress occupies an important place among the inducers of cytokine production. This fact has been confirmed by our experiments. Experimental "social" stress is accompanied by changes in the production of IL-1β, IL-4, IL-6, TNF-α, TGF-β1, which allowed us to consider stress as the main inducer of the production of proinflammatory cytokines and growth factors.

Conclusion:

Evaluation of the effect of Semax on the level of cytokines under conditions of "social" stress showed that the effect of Semax is aimed at restoring the level of the studied cytokines in the group of stressed animals.

[The Peptide Drug ACTH(4-7)PGP (Semax) Suppresses mRNA Transcripts Encoding Proinflammatory Mediators Induced by Reversible Ischemia of the Rat Brain]

Due to its nootropic, neuroprotective, and immunomodulatory effects, the peptide Semax is utilized in the treatment of ischemic stroke. Our earlier RNA-Seq analysis of the transcriptome in an ischemic model of transient occlusion of the middle cerebral artery showed an increase in the mRNA levels of many proinflammatory genes, and the suppression of their induction by Semax. However, for many relevant genes, including Il1a, Il1b, Il6 and Tnfa, the levels of their expression were too low for detailed quantitative evaluation. Here we utilize qRT-PCR to analyze the effects of the Semax peptide on the expression of weakly expressed mRNAs encoding several proinflammatory mediators, and show that exposure to Semax leads to a statistically significant decrease in the Il1a, Il1b, Il6, Ccl3, and Cxcl2 mRNAs, which compensates for the increase in the transcription of these genes induced by ischemia-reperfusion. We conclude that the observed protective effect of Semax in the model of stroke may be due to its anti-inflammatory effects. We also discuss the limitations of the RNA-Seq when applied to quantifying less abundant transcripts as compared to the real-time RT-PCR method.

Assessment of the Cytotoxicity of Peptide Modifications of Doxorubicin on Tetrahymena pyriformis

The cytotoxicity of doxorubicin (Dox) and its peptide modifications Z-Gly-Pro-Dox and Boc-Gly-Pro-Dox were studied. Tetrahymena pyriformis was used as a test system, which made it possible, due to the short life cycle and high reproduction rate of ciliates, to trace their response to the effects of toxicants over several generations. It was found that peptide modification of the Dox molecule markedly reduces its cytotoxic and cytostatic effect. The Z-Gly-Pro-Dox modification has less cytotoxic and cytostatic effect compared to Boc-Gly-Pro-Dox. When determining the ability of drugs (at a concentration of 100 μM) to prevent bacterial contamination of samples, it was shown that the smallest degree of overgrowth was recorded in the presence of Dox (OD_600nm 81.1). Boc-Gly-Pro-Dox also had a bacteriostatic effect, though less pronounced (OD_600nm 93.8). The degree of overgrowth in the presence of Z-Gly-Pro-Dox was close to that of distilled water. The results obtained on ciliates did not contradict the data obtained in similar studies on mice.

Semax, synthetic ACTH(4-10) analogue, attenuates behavioural and neurochemical alterations following early-life fluvoxamine exposure in white rats

Selective serotonin reuptake inhibitors (SSRI) are commonly used to treat depression during pregnancy. SSRIs cross the placenta and may influence the maturation of the foetal brain. Clinical and preclinical findings suggest long-term consequences of SSRI perinatal exposure for the offspring. The mechanisms of SSRI effects on developing brain remain largely unknown and there are no directional approaches for prevention of the consequences of maternal SSRI treatment during pregnancy. The heptapeptide Semax (MEHFPGP) is a synthetic analogue of ACTH(4-10) which exerts marked nootropic and neuroprotective activities. The aim of the present study was to investigate the long-term effects of neonatal exposure to the SSRI fluvoxamine (FA) in white rats. Additionally, the study examined the potential for Semax to prevent the negative consequences of neonatal FA exposure. Rat pups received FA or vehicle injections on postnatal days 1-14, a time period equivalent to 27-40 weeks of human foetal age. After FA treatment, rats were administered with Semax or vehicle on postnatal days 15-28. During the 2nd month of life, the rats underwent behavioural testing, and monoamine levels in brain structures were measured. It was shown that neonatal FA exposure leads to the impaired emotional response to stress and novelty and delayed acquisition of food-motivated maze task in adolescent and young adult rats. Furthermore, FA exposure induced alterations in the monoamine levels in brains of 1- and 2- month-old rats. Semax administration reduced the anxiety-like behaviour, improved learning abilities and normalized the levels of brain biogenic amines impaired by the FA exposure. The results demonstrate that early-life FA exposure in rat pups produces long-term disturbances in their anxiety-related behaviour, learning abilities, and brain monoamines content. Semax exerts a favourable effect on behaviour and biogenic amine system of rats exposed to the antidepressant. Thus, peptide Semax can prevent behavioural deficits caused by altered 5-HT levels during development.

Neuroprotective Effects of Peptides in the Brain: Transcriptome Approach

The importance of studying the action mechanisms of drugs based on natural regulatory peptides is commonly recognized. Particular attention is paid to the peptide drugs that contribute to the restoration of brain functions after acute cerebrovascular accidents (stroke), which for many years continues to be one of the main problems and threats to human health. However, molecular genetic changes in the brain in response to ischemia, as well as the mechanisms of protective effects of peptides, have not been sufficiently studied. This limits the use of neuroprotective peptides and makes it difficult to develop new, more efficient drugs with targeted action on brain functions. Transcriptome analysis is a promising approach for studying the mechanisms of the damaging effects of cerebral ischemia and neuroprotective action of peptide drugs. Beside investigating the role of mRNAs in protein synthesis, the development of new neuroprotection strategies requires studying the involvement of regulatory RNAs in ischemia. Of greatest interest are microRNAs (miRNAs) and circular RNAs (circRNAs), which are expressed predominantly in the brain. CircRNAs can interact with miRNAs and diminish their activity, thereby inhibiting miRNA-mediated repression of mRNAs. It has become apparent that analysis of the circRNA/miRNA/mRNA system is essential for deciphering the mechanisms of brain damage and repair. Here, we present the results of studies on the ischemia-induced changes in the activity of genes and peptide-mediated alterations in the transcriptome profiles in experimental ischemia and formulate the basic principles of peptide regulation in the ischemia-induced damage.

Morphofunctional State of the Large Intestine in Rats under Conditions of Restraint Stress and Administration of Peptide ACTH(4-7)-PGP (Semax)

We studied the effect of intraperitoneal administration ACTH_(4-7)-PGP in doses of 5, 50, 150, and 450 μg/kg to Wistar male rats 12-15 min before modeling restraint stress on the morphofunctional state of the colon. In rats exposed to restraint stress, signs of atrophy and inflammatory reaction in the colon wall, changes in functional activity and number of mast cells, and increased serum level of corticosterone were observed. Administration of the peptide led to a decrease in corticosterone concentration, alleviated stress-induced pathomorphological changes, and promoted adaptation of the intestinal wall to stress. The positive effects of ACTH_(4-7)-PGP can be determined by multifunctional nature of the physiological and pharmacological effects of the neuropeptide.

Thromboelastographic Research of Arginine-, Leucine and Lysine-Containing Peptides

Anticoagulant effects of 12 short peptides of the glyproline series - Arg-Glu-Arg-Pro-Gly-Pro (RERPGP), Arg-Glu-Arg-Val-Gly-Pro (RERVGP), Arg-Glu-Arg-Gly-Pro (RERGP), Arg-Pro-Gly-Pro (RPGP), Pro-Leu-Pro (PLP), Pro-Leu-Pro-Ala (PLPA), Pro-Gly-Pro-Leu (PGPL), Phe-Pro-Leu-Pro-Ala (FPLPA), Pyr-Arg-Pro (PyrRP), Lys-Lys-Arg-Arg-Pro-Gly-Pro (KKRRPGP), Arg-Lys-Lys-Arg-Pro-Gly-Pro (RKKRPGP), and Lys-Arg-Lys-Pro-Gly-Pro (KRKPGP) in concentrations of 10-3 and 10-2 mg/ml in vitro was demonstrated by the thromboelastographic method. The effects of 6 peptides ((RERPGP, RPGP, PLP, PLPA, RKKRPGP, and KKRRPGP) were also observed in vivo after intranasal or oral administration. Changes in the studied thromboelastographic parameters towards hypocoagulation in comparison with the control group were noted. Arginine and leucine glyprolines produced the maximum anticoagulant effect.

Pharmacotranscriptomics of peptide drugs with neuroprotective properties

Here we present a review of studies on the effects of peptides with neuroprotective properties on gene transcription in nerve cells. The few published works in this area clearly demonstrate massive changes in cell transcriptomes induced by peptides under normal conditions and under conditions of experimental brain ischemia. These changes significantly affect signaling and metabolic pathways, affecting various body systems and confirming the multiple target actions of peptides. The importance of noncoding RNAs in the regulation of these processes is shown, and we discuss the prospects of research for determining the main mechanisms of peptide regulation, which is necessary for the further development of drugs with targeted neuroprotective effects.

Neuroprotective Potential of Peptides HFRWPGP (ACTH6-9PGP), KKRRPGP, and PyrRP in Cultured Cortical Neurons at Glutamate Excitotoxicity

Glutamate (Glu) excitotoxicity, which accompanies brain ischemia or traumatic brain injury, is the leading mechanism of neuronal death. In the present work, we studied the effects of the peptides HFRWPGP (ACTH_6-9PGP), KKRRPG, and PyrRP on the survival of cultured cortical neurons on the background of excitotoxic effect of Glu (100 µM). Biochemical (MTT/WST) and morphometric analyzes showed that, depending on the dose, ACTH_6-9PGP and KKRRPGP protect neurons from the cells death, while PyrRP, conversely, enhances it. The neuroprotective effect of ACTH_6-9PGP is accompanied by a slowdown in the development of delayed calcium dysregulation and synchronous mitochondrial depolarization. Among the studied peptides, only ACTH_6-9PGP significantly increased the number of neurons that restored Ca²⁺ homeostasis after Glu was abolished. The influence of KKRRPGP was less pronounced, whereas PyrRP, on the contrary, reduced the number of neurons with low [Ca²⁺]_i. Thus, this study revealed the high therapeutic significance of ACTH_6-9PGP and allowed assessing the prospects for its possible clinical use.

Functional Connectomic Approach to Studying Selank and Semax Effects

The present study was aimed at the assessment of effects of anxiolytic Selank and nootropic Semax on the whole-brain resting-state functional connectivity (FC) of each of the predefined regions of interest (ROIs) in 52 healthy participants. The ROIs included amygdala (one of the key regions for the regulation of anxiety) and dorsolateral prefrontal cortex (DLPFC; the key region for executive functions, including working memory) in the right and left hemisphere. Resting-state fMRI was carried out three times, namely before, after 5 and 20 min of the injection of either Semax, or Selank, or placebo. Between-group alongwith between-condition differences were revealed in FC between the right amygdala and a region in fusiform, inferior and middle temporal as well as parahippocampal gyri in the right hemisphere. Post hoc analysis allowed us to define both general and specific effects of Selank and Semax on FC between the right amygdala and the right temporal cortex for the first time.

[Study of stability of proline-containing derivatives of dopamine and serotonin in the biological media in vitro experiments]

Boc-Gly-Pro-DP, Z-Gly-Pro-DP, LA-Gly-Pro-DP, Boc-Gly-Pro-Srt, Z-Gly-Pro-Srt were synthesized for the first time. The stability of these compounds in the presence of leucine aminopeptidase, carboxypeptidase Y, carboxypeptidase B and proline endopeptidase (PEP) was determined. It turned out that the compounds are stable in the presence of aminopeptidases and carboxypeptidases. In the presence of PEP, dopamine (DP) and serotonin (Srt) are cleaved from the synthesized preparations. Thus, new proline-containing Srt and DP derivatives were obtained, Srt and DP could be gradually released from them. This suggest the possibility of a prolonged action of these biologically active compounds on the vital activity of cells and, consequently, of the whole organism.

Effect of a New Synthetic Peptide Preparation AСTH15-18PGP on the Hemostasis System in Rats

We studied the effect of chronic intranasal and peroral administration of a new peptide preparation AСTH_15-18PGP in a dose of 100 mg/kg body weight on the state of vascular-platelet and plasma hemostasis in animals. It was found that this synthetic regulatory peptide administered intranasally can produce antiplatelet, anticoagulant, and antifibrin-stabilizing effects on the blood plasma in healthy rats. In both administration routes, the peptide induced activation of the anticoagulation system of the hemostasis by increasing enzymatic and non-enzymatic fibrinolysis; after intranasal administration, the fibrinolytic effects were more pronounced.

The Use of Human Induced Pluripotent Stem Cells for Testing Neuroprotective Activity of Pharmacological Compounds

Development of therapeutic preparations involves several steps, starting with the synthesis of chemical compounds and testing them in different models for selecting the most effective and safest ones to clinical trials and introduction into medical practice. Cultured animal cells (both primary and transformed) are commonly used as models for compound screening. However, cell models display a number of disadvantages, including insufficient standardization (primary cells) and disruption of cell genotypes (transformed cells). Generation of human induced pluripotent stem cells (IPSCs) offers new possibilities for the development of high-throughput test systems for screening potential therapeutic preparations with different activity spectra. Due to the capacity to differentiate into all cell types of an adult organism, IPSCs are a unique model that allows examining the activity and potential toxicity of tested compounds during the entire differentiation process in vitro. In this work, we demonstrated the efficiency of IPSCs and their neuronal derivatives for selecting substances with the neuroprotective activity using two classes of compounds - melanocortin family peptides and endocannabinoids. None of the tested compounds displayed cyto- or embryotoxicity. Both melanocortin peptides and endocannabinoids exerted neuroprotective effect in the neuronal precursors and IPSC-derived neurons subjected to hydrogen peroxide. The endocannabinoid N-docosahexaenoyl dopamine exhibited the highest neuroprotective effect (~70%) in the differentiated cultures enriched with dopaminergic neurons; the effect of melanocortin Semax was ~40%. The possibility of using other IPSC derivatives for selecting compounds with the neuroprotective activity is discussed.

[Stability of prolin-containing peptides in biological media]

New data on peptide drugs have been summarized; their high stability is due to both the introduction of Pro-Gly-Pro in various amino acid sequences and the modification of the glyproline fragment itself. Pro-Gly-Pro-Leu, ACTH(6-9)Pro-Gly-Pro, 5-oxo-Pro-Arg-Pro and 5-oxo-Pro-His-Pro-NH2 were used as proline-containing peptides. Tritiated peptides were obtained: Pro-Gly-Pro-Leu with specific radioactivity of 135 Ci/mmol, ACTH(6-9)Pro-Gly-Pro - 26 Ci/mmol, 5-oxo-Pro-Arg-Pro - 60 Ci/mmol and 5-oxo-Pro-His-Pro-NH2 - 75 Ci/mmol. The concentration of Pro-Gly-Pro-Leu, ACTH(6-9)Pro-Gly-Pro, 5-oxo-Pro-Arg-Pro and 5-oxo-Pro-His-Pro-NH2 in the blood was found to be about 200 times more than in the brain for intranasal administration, and in average 600 times more for intravenous administration. The stability of proline-containing peptides in vitro experiments was determined using different commercially available peptidases (leucine aminopeptidases, dipeptidases, carboxypeptidases B and Y), and using nasal mucus, microsomal fraction of the rat brain (IMPC) and rat blood plasma. During peptidase hydrolysis of Pro-Gly-Pro-Leu, the main metabolites were Gly-Pro-Leu, Pro-Gly-Pro, Gly-Pro and Pro-Gly. For ACTH(6-9)Pro-Gly-Pro, the main metabolites were Phe-Arg-Trp-Pro-Gly-Pro and Trp-Pro-Gly-Pro. In peptidase hydrolysis of 5-oxo-Pro-His-Pro-NH2, the major metabolite was 5-oxo-Pro-His-Pro. It was shown that with different methods of peptides administration the composition of the metabolites formed is different. Based on the data obtained, resistance to enzymatic cleavage of peptides and their metabolic pathways were evaluated. Thus, these new data have shown that the above approaches can be used to prolong the action of glyprolines in living objects. In this case, the degradation of proline-containing peptides occurs mainly not due to the action of proteases, but due to other ways of degradation. In general, the data presented in the review indicate the promise of intranasal way of introducing biologically active peptides into the brain of living organisms.

An integrated approach to study the molecular aspects of regulatory peptides biological mechanism

An integrated methodological approach to study the molecular aspects of short regulatory neuropeptides biological mechanism is proposed. The complex research is based on radioligand-receptor method of analysis and covers such points of peptides molecular activity as: specific binding of peptides to brain cells plasmatic membranes, formation of tissue specific synacton, influence of peptides (as allosteric modulators) on functionality of different neuroreceptors as well as delayed in time effects of peptides on receptor-binding activity of well-known neuroreceptor systems. Radiolabeled ligands in such complex study are the one of the best and precision instruments to uncover the molecular mechanism of multiple and multitarget biological effects of regulatory peptides. In this issue we used heptapeptide Semax as a model regulatory peptide, [³ H]Ach and [³ H]GABA as an effector molecules, and the rat model of stress-induced memory and behavior impairment as a morbid state. We showed the ability of Semax to modulate in a dose-dependent manner [³ H]Ach and [³ H]GABA specific binding to some of its corresponding receptors as well as to affect the number of [³ H]GABA specific binding places on rat neurons plasmatic membranes after complex stress exposure.

Effect of Selank on Morphological Parameters of Rat Liver in Chronic Foot-Shock Stress

We studied the effects of Selank on morphological parameters of the liver in Wistar male rats subjected to chronic foot-shock stress. Selank was injected intraperitoneally in doses of 100, 300 and 1000 μg/kg 15 min before each stress session. Morphological and morphometrical analysis showed that chronic foot-shock stress induced hydropic degeneration of hepatocytes, an increase of the nucleus/cytoplasm ratio due to an increase in the area of nuclei and reduction of the cytoplasm area, the appearance of focal necroses, and lymphohistiocyte infiltration. Injection of Selank in all doses reduced the intensity of stress-induced degenerative changes. Administration of Selank in doses of 300 and 1000 μg/kg restored the nucleus/cytoplasm ratio in hepatocytes. The maximum stress-limiting effect was attained after administration of 300 μg/kg Selank.

Neuroprotective Action of Amidic Neurolipins in Models of Neurotoxicity on the Culture of Human Neural-Like Cells SH-SY5Y

It was established that in neurodegeneration models in the human neuron-like cell line SH-SY5Y, amide derivatives of arachidonic and docosahexaenoic acids were inactive in experiments with MPP⁺ and CoCl₂ but protected from H₂O₂. The protective activity of neurolipins decreased in the series DHA-DA > AA-SER ≥ AA-GLY > AA-GABA ≥ AA-EA and was manifested starting from a concentration of 0.5 nM.

Experimental Substantiation of Application of Semax as a Modulator of Immune Reaction on the Model of "Social" Stress

We studied immunocorrecting effects of Semax (Met-Glu-His-Phe-Pro-Gly-Pro) on the model of "social" stress caused by sensory contact and intermale confrontation. Functional activity of the immune system of laboratory animals was evaluated in standard immunopharmacological tests: delayed-type hypersensitivity reaction, direct agglutination test, latex test for studying phagocytic activity of peripheral blood neutrophils, changes in differential leukocyte count, and weight of immunocompetent organs. It was found that changes in the immune response caused by "social" stress are multidirectional, which confirms the theory of stress-induced "immune imbalance". Semax acted as effective immune corrector restoring cellular and humoral immunogenesis reactions and phagocytic activity of neutrophils. This attested to the presence of immunomodulating properties in Semax and necessitates further studies in this field.

Modulation of GABA- and Glycine-Activated Ionic Currents with Semax in Isolated Cerebral Neurons

The concentration-clamp experiments with neurons isolated from the rat brain showed that nootropic and neuroprotective drug Semax added to perfusion solution at concentration of 1 μM augmented the amplitude of GABA-activated ionic currents in cerebellum Purkinje cells by 147±13%. In addition, Semax in perfusion solution (0.1 and 1 μM) diminished the amplitude of glycine-activated chloride currents in hippocampal pyramidal neurons down to 68 and 43% control level, respectively. Both potentiating and inhibitory effects developed slowly, and they were poorly reversible, which indicated a probable implication of second messengers in the observed phenomena. Semax accelerated the falling edge of glycine-activated current both after a short-term co-application with agonist and after addition of this peptide into perfusion solution.

[Oxoprolinic short peptides - potential pharmacological means of hypolidemic and antitrombotic actions]

One of the most urgent and important tasks of modern biological and medical research is the search and research of pharmacological agents that combine lipid-lowering and antithrombotic effects in the organism. The unique effects of the regulatory peptides of the oxoproline series (5-oхo-Pro-His-Pro-NH2, 5-oxo-Pro-Trp-Pro and 5-oxo-Pro-Arg-Pro or 5-oхo-Pro-His-Pro-NH2, Pyr-Trp-Pro and Pyr-Arg-Pro) have been found in rats with hypercholesterolemia (metabolic syndrome). Multiple intranasal of these peptides to animals with developed hypercholesterolemia increased anticoagulant, fibrinolytic and antiplatelet potential of the blood and simultaneously lowered increased concentrations of total cholesterol, low-density lipoprotein cholesterol and triglycerides. In addition, they contributed to the normalization of blood glucose levels. A week after the last admistration of these peptides, the hypocholesterolemic, normoglycemic and anticoagulant effects persisted. The relationship between the structure of peptides of the oxoproline series and their functional properties is discussed. A conclusion is made about the prospects of further studies of oxoproline peptides as drugs that combine antithrombotic effects with the improvement of fat metabolism in the body.

Synthesis of N-acyl derivatives of Pro-Gly-Pro-Leu peptide: Proteolytic stability in vitro and effects on mouse macrophage cells RAW264.7

Acetyl, oleoyl, arachidonoyl, and docosahexaenoyl derivatives of the Pro-Gly-Pro-Leu peptide with a chemical purity of 99.8% were synthesized. The degradation kinetics of the Pro-Gly-Pro-Leu derivatives under the action of leucine aminopeptidase, nasal mucus, and microsomal fraction of the brain and blood of rats was studied. It was shown that the N-acyl derivatives of Pro-Gly-Pro-Leu proved to be more resistant to the action of leucine aminopeptidase and other enzyme systems. The study of the cytotoxic and anti-inflammatory activity of preparations on the mouse macrophage cell line RAW264.7 showed that acylation with oleic and arachidonic acid makes the peptide cytotoxic with LC50 in the range of 70-15 μM and gives it anti-inflammatory properties with EC50 of 32 and 36 μM, respectively.

Effect of Selank on Functional State of Rat Hepatocytes under Conditions of Restraint Stress

We studied the effect of Selank administered intraperitoneally in doses of 100, 300, and 1000 μg/kg to male Wistar rats 15 min prior to restraint stress on the content of aminotransferases and total protein concentration in blood serum and intensity of free radical oxidation in the liver. Under conditions of acute restraint stress, Selank in doses of 100 and 300 μg/kg decreased catalase and superoxide dismutase activities and malondialdehyde concentration and increased total antioxidant activity in the liver homogenate. Administration of Selank in a dose of 1000 μg/kg reduced the content of aminotransferases in blood serum, decreased superoxide dismutase activity in the liver, and increased total antioxidant activity. Under conditions of chronic stress, Selank in all doses produced similar effects: reduced superoxide dismutase activity and malondialdehyde concentration in the liver tissue and AST activity in the serum. The other parameters remained unchanged.

Systemic N-terminal fragments of adrenocorticotropin reduce inflammation- and stress-induced anhedonia in rats

Emerging evidence implicates impaired self-regulation of the hypothalamic-pituitary-adrenal (HPA) axis and inflammation as important and closely related components of the pathophysiology of major depression. Antidepressants show anti-inflammatory effects and are suggested to enhance glucocorticoid feedback inhibition of the HPA axis. HPA axis activity is also negatively self-regulated by the adrenocorticotropic hormone (ACTH), a potent anti-inflammatory peptide activating five subtypes of melanocortin receptors (MCRs). There are indications that ACTH-mediated feedback can be activated by noncorticotropic N-terminal ACTH fragments such as a potent anti-inflammatory MC1/3/4/5R agonist α-melanocyte-stimulating hormone (α-MSH), corresponding to ACTH(1-13), and a MC3/5R agonist ACTH(4-10). We investigated whether intraperitoneal administration of rats with these peptides affects anhedonia, which is a core symptom of depression. Inflammation-related anhedonia was induced by a single intraperitoneal administration of a low dose (0.025mg/kg) of lipopolysaccharide (LPS). Stress-related anhedonia was induced by the chronic unpredictable stress (CUS) procedure. The sucrose preference test was used to detect anhedonia. We found that ACTH(4-10) pretreatment decreased LPS-induced increase in serum corticosterone and tumor necrosis factor (TNF)-α, and a MC3/4R antagonist SHU9119 blocked this effect. Both α-MSH and ACTH(4-10) alleviated LPS-induced anhedonia. In the CUS model, these peptides reduced anhedonia and normalized body weight gain. The data indicate that systemic α-MSH and ACTH(4-10) produce an antidepressant-like effect on anhedonia induced by stress or inflammation, the stimuli that trigger the release of ACTH and α-MSH into the bloodstream. The results suggest a counterbalancing role of circulating melanocortins in depression and point to a new approach for antidepressant treatment.

Influence of ACTG4-7-PGP (Semax) on Morphofunctional State of Hepatocytes in Chronic Emotional and Painful Stress

We studied the effect of intraperitoneal administration of peptide ACTG_4-7-PGP to male Wistar rats in doses of 5, 50, 150, and 450 μg/kg on the morphofunctional state of hepatocytes in chronic emotional and painful stress. A dose-dependent stress-limiting effect of the peptide was observed: it normalized the protein synthesis function of the liver and serum activity of ALT. The anticytolytic effect of the peptide increased with increasing its dose against the background of the increase in the relative number of multinucleated and multinucleolated cells and deceleration of the recovery of serum protein concentration. The decrease of hepatocyte cytolysis against the background of more intense morphological signs of protein synthesis processes attests to activation of reparative processes in the liver parenchyma via enhanced constitutional synthesis of protein.

Peptides semax and selank affect the behavior of rats with 6-OHDA induced PD-like parkinsonism

Parkinson's disease (PD) is the second most common severe neurodegenerative disorder that is characterized by progressive degeneration of dopaminergic neurons (DA neurons) in the substantia nigra pars compacta (SNpc) region of the brain. In the present study, we investigated the effects of the synthetic regulatory peptides Semax (analog of an ACTH 4-10 fragment (ACTH4-10)) and Selank (analog of immunomodulatory taftsin) on behavior of rats with 6-hydroxidopamine (6-OHDA) induced PD-like parkinsonism. It was showed that both peptides did not affect motor activity of rats in elevated cross shaped maze and passive defensive behavior of the animals. At the same time, Selank decreased level of anxiety of rats with toxic damage of DA neurons in elevated cross shaped maze. Previously such effects of Selank were revealed in healthy rodents (rats and mice) with different models of psycho-emotional stress. Therefore, toxic damage of substantia nigra does not affect the response of the rat organism on this peptide.

Fibroblast-like cells as an effective feeder for the cultivation and derivation of new lines of human induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) can be a highly informative model of hereditary and sporadic human diseases. In the future, such cells can be used in substitution and regenerative therapy of a wide range of diseases and for the treatment of injuries and burns. The ability of iPSCs derived from patients with Parkinson's disease to differentiate into fibroblast-like cells (derivatives) was studied. It was found that these cells can serve as an effective feeder layer not only to maintain the pluripotency of allogenic and autologous iPSCs but also to derive new iPSC lines.

Anxiolytic activity of the neuroprotective peptide HLDF-6 and its effects on brain neurotransmitter systems in BALB/c and C57BL/6 mice

This study is focused on a new amide derivative of the peptide HLDF-6 (Thr-Gly-Glu-Asn-His-Arg). This hexapeptide is a fragment of Human Leukaemia Differentiation Factor (HLDF). It displays a broad range of nootropic and neuroprotective activities. We showed, for the first time, that the peptide HLDF-6-amide has high anxiolytic activity. We used 'open field' and 'elevated plus maze' tests to demonstrate anxiolytic effects of HLDF-6-amide (0.1 and 0.3 mg/kg intranasally), which were comparable to those of the reference drug diazepam (0.5 mg/kg). Five daily equipotent doses of HLDF-6-amide selectively mitigated anxiety and increased the density of NMDA receptors in the hippocampus of stress-susceptible BALB/c mice, and had no effect on stress-resilient C57BL/6 mice. The subchronic administration of HLDF-6-amide showed no effect on the density of GABAA and nicotine receptors but was accompanied by a nonselective decrease of the 5-HT2A serotonin receptor density in frontal cortex of both strains. The mechanism of the specific anxiolytic activity of HLDF-6-amide may include its action on the NMDA-glutamatergic receptor system of the hippocampus and on serotonin 5-HT2A-receptors in the prefrontal cortex. The psychotropic activity of HLDF-6-amide is promising for its introduction to medical practice as a highly effective anxiolytic medicine for mental and neurological diseases.

Investigation of the effects of GABA receptor agonists in the differentiation of human induced pluripotent stem cells into dopaminergic neurons

The influence of GABA receptor agonists on the terminal differentiation in vitro of dopaminergic (DA) neurons derived from IPS cells was investigated. GABA-A agonist muscimol induced transient elevation of intracellular Ca²⁺ level ([Ca²⁺] _i ) in the investigated cells at days 5 to 21 of differentiation. Differentiation of cells in the presence of muscimol reduced tyrosine hydroxylase expression. Thus, the presence of active GABA-A receptors, associated with phenotype determination via Ca²⁺-signalling was demonstrated in differentiating human DA neurons.

Glutamate release and uptake processes are altered in a new mouse model of amyotrophic lateral sclerosis

In this paper, we showed that in the cortex of mice expressing an abberant form of FUS protein that model amyotrophic lateral sclerosis (ALS), the processes of KCl-induced and basal [(3)H]glutamate release and uptake are altered at the presymptomatic stage as compared to the non-transgenic littermates. The change in these three parameters in transgenic animals causes excitotoxicity, which, in turn, may lead to massive loss of motor neurons and the onset of ALS symptoms.

Semax prevents learning and memory inhibition by heavy metals

Separate and joint effect of Semax, ascorbic acid, lead diacetate, and ammonium molybdate on avoidance conditioning in rats was studied. It was established that the heavy metal salts inhibited the avoidance response, and the peptide counteracted this inhibition as strongly as ascorbic acid or to a comparable degree. These findings confirm the antioxidant properties of Semax.

Effect of Proline-Containing Oligopeptides PGP and RGP on Proliferative and Protein-Synthesizing Activity of Cultured Pulmonary Fibroblasts under Conditions of Oxidative Stress

We studied the effect of glyprolines Pro-Gly-Pro (PGP) and Arg-Gly-Pro (RGP) on the primary culture of pulmonary fibroblasts from newborn albino rats under normal conditions and during oxidative stress. Under physiological conditions, the peptides had no effect on parameters of cell division. Hydrogen peroxide induced intensive oxidative stress accompanied by suppression of protein-synthesizing function. When hydrogen peroxide was added to the culture containing the test peptides, correction of the oxidative status was observed accompanied by activation of DNA-synthesizing activity and inhibition of lucigenin-dependent chemiluminescence.

Investigation of the effect of α-melanocyte-stimulating hormone on proliferation and early stages of differentiation of human induced pluripotent stem cells

We have studied the influence of α-melanocyte-stimulating hormone (α-MSH) on proliferation and early stages of differentiation of human induced pluripotent stem cells (iPSc). We have demonstrated that α-MSH receptor genes are expressed in undifferentiated iPSc. The expression levels of MCR1, MCR2, and MCR3 increased at the embryoid body (EB) formation stage. The formation of neural progenitors was accompanied by elevation of MCR2, MCR3, and MCR4 expression. α-MSH had no effect on EB generation and iPSc proliferation at concentrations ranging from 1 nM to 10 μM. At the same time, α-MSH increased the generation of neural rosettes in human iPSc cultures more than twice.

[The Qualitative Analysis of the Amide Derivative of HLDF-6 Peptide and Its Metabolites with the Use of Tritium- and Deuterium-Labeled Derivatives]

The goal of the study was to elaborate the pharmacokinetics methods of the amide derivative of peptide HLDF-6 (TGENHR-NH2) and its range of nootropic and neuroprotective activity is wide. The hexapeptide 41TGENHR46 is a fragment of the HDLF differentiation factor. It forms the basis for the development of preventive and therapeutic preparations for treating cerebrovascular and neurodegenerative conditions. Pharmacokinetic and molecular mechanisms of the action of the HLDF-6 peptide were studied using tritium- and deuterium-labeled derivatives of this peptide, produced with the use of the high-temperature solid-state catalytic isotope exchange reaction (HSCIE). This reaction was employed to produce the tritium-labeled peptide [3H]TGENHR-NH2 with a molar radioactivity of 230 Ci/mmol and the deuterium-labeled peptide [2H]TGENHR-NH2 with an average deuterium incorporation equal to 10.5 atoms. It was shown by the NMR spectroscopy that the isotope label distribution over the labeled peptide's molecule was uniform, which allowed qualitative analysis ofboth the peptide itself and its fragments in the organism's tissues to be conducted. The newly developed pharmacokinetics method makes it possible to avoid almost completely losses of the peptides under study due to biodegradation during the analysis of tissues. These labeled peptides were used in mice, rats and rabbits to study the pharmacokinetics of the peptide and to calculate the values of its principal pharmacokinetic parameters. Characteristics of its pharmacokinetic profile in the blood were obtained, the hypothesis of pharmacokinetics linearity tested, its metabolism analyzed and its bioavailability value, 34%, calculated. It has been shown that the studied TGENHR-NH2 peptide shows high resistance to hydrolysis in the blood plasma, with dipeptidyl aminopeptidases making the largest contribution to its hydrolysis.

Glyprolines exert protective and repair-promoting effects in the rat stomach: potential role of the cytokine GRO/CINC-1

Glyprolines have been reported to exert protective effects in the stomach. In this study, we examined the potential effects of intranasal administration of Pro-Gly-Pro (PGP) and N-acetyl-Pro-Gly-Pro (AcPGP) on experimental gastric ulcer formation and healing. We also studied gastric release of the cytokine GRO/CINC-1, and its potential role in ulcer development and healing. Gastric ulcers were induced in rats by applying acetic acid to the serosa of the stomach. PGP and AcPGP were then administered at a dose of 3.7 μmol/kg once daily on either days 1 - 3 (ulcer formation) or days 4 - 6 (ulcer healing). Measurement of ulcer area and histological examination of gastric tissue were carried out on days 4 and 7 after application of acetic acid. In vitro studies involved addition of the glyprolines to cultured rat gastric epithelial cells with or without lipopolysaccharide. Reverse transcription PCR, real-time PCR and ELISA were used for cytokine analysis. PGP and AcPGP significantly reduced ulcer areas on the 4(th) day and accelerated the healing on the 7(th) day compared with the control. After acetic acid-induced ulceration, the expression of GRO/CINC-1 mRNA in gastric tissue was increased 9-fold versus the sham-operated group. Treatment with PGP or AcPGP both significantly suppressed the expression of GRO/CINC-1 mRNA in gastric tissue. However, the glyprolines did not alter LPS-induced mRNA expression or release of GRO/CINC-1 from cultured rat gastric epithelial cells, even though those cells were harvested from rats subjected to the ulcer-induction procedure. The results of this study show that intranasal administration of PGP and AcPGP significantly increased resistance against acetic acid-induced ulceration and accelerated healing in the rats. These effects may be due, at least in part, to their ability to reduce the acetic acid-induced GRO/CINC-1 expression and production in gastric tissue.

Penetration of thyroliberin in the blood and brain regions at intranasal or intravenous administration

The maximum amounts of the thyroliberin in the blood and brain of rats at intranasal and intravenous administration were determined. It is found that rat hippocampal, cortical, and cerebellar membranes contain two types of specific binding sites (high- and low-affinity) for the labeled ligand. It was shown that, at intranasal and intravenous administration, maximum amounts of the thyroliberin were detected in the cerebellum and then in the cortex and hippocampus. The degradation of the thyroliberin in the rat brain and its regions at intranasal and intravenous administration was studied. It is shown that the degree of degradation and the formation of proteolytic products of the thyroliberin is different in different regions of the rat brain.

Correlation analysis of cytokine gene expression changes and antiulcer effects of Pro-Gly-Pro and N-Acetyl-Pro-Gly-Pro in experimental models of ulceration

Direct correlation of the cytokine gene expression level in peripheral blood mononuclear cells (BMNCs) and gastric mucosa (GM) cells with the development of gastric ulcers of various etiologies was shown for the first time. Ethanol-induced ulceration causes an increased transcription of IFNa, IL-8, and IL-12 mRNA in BMNCs. GM damages caused by water immersion stress were accompanied by an increased transcription of TNFa. The sizes of acetate-induced damages were positively correlated with the expression of IL-10 and IL-8 genes in BMNCs and with the expression of IFNa, IL-2, IL-12, and TNF genes in GM cells. Intranasal administration of Pro-Gly-Pro (PGP) reduced ethanol-induced ulceration, activating the transcription of IFNγ, IL-2, and IL-4 mRNA in BMNCs and prevents the formation of stress- and acetateinduced ulcers by inhibiting the expression of IL-8 and IL-10 genes, respectively.

[POSSIBLE ROLE OF TRANSTHYRETIN IN THE BIOLOGICAL MECHANISM OF THE REGULATORY PEPTIDE NEUROPROTECTION.]

The peptide preparation Semax has been effectively used for therapy of ischemic stroke. However, the mechanisms of its action are insufficiently understood and actively studied. The full-genome analysis of the transcriptome implemented in our recent work dem- onstrated that under conditions of focal ischemia of rat brain the Semax modified the profile of the transcription activity of many genes. In this case, the difference in the transcription levels of the gene encoding the protein transthyretin (Ttr) expression in rats under the pathological conditions of ischemia and in the presence of Semax was very high. High similarity between the effects of Ttr and coupled molecular systems with the Semax effects in ischemic stroke allowed us to suggest that the neuroprotection mechanisms of Semax (and, possibly, of other neuroprotection mechanisms of Semax) could be mediated by Ttr. In this review, we discussed the role of Ttr in CNS and its possible role in the neuroprotection mechanism of Semax.

[EFFECT OF PEPTIDE SEMAX ON SYNAPTIC ACTIVITY AND SHORT-TERM PLASTICITY OF GLUTAMATERGIC SYNAPSES OF CO-CULTURED DORSAL ROOT GANGLION AND DORSAL HORN NEURONS]

The influence of long-term culturing (12 days in vitro) of dorsal root ganglion (DRG) and dorsal horn (DH) neurons with peptide Semax on the level of synaptic activity at co-cultures, as well as short-term plasticity in sensory synapses were studied. It has been shown that neuronal culturing with peptide at concentrations of 10 and 100 µM led to increasing the frequency of spontaneous glutamatergic postsynaptic currents in DH neurons to 71.7 ± 1.8% and 93.9 ± 3.1% (n = 6; P < 0.001); Semax has a not significant effect on the amplitude and frequency of miniature glutamatergic currents, but causes an increase of the amplitudes of spontaneous postsynaptic currents, as well as elevates the quantum content. The data show the increase of multivesicular glutamate release efficiency in neural networks of co-cultures following incubation with the peptide. Also Semax (10 and 100 µM) induces changes of the basic parameters of short-term plasticity in sensory synapses: (1) increasing the paired-pulse ratio from 0.53 ± 0.028 (n = 8) to 0.91 ± 0.072 (n = 6, P < 0.01) and 0.95 ± 0.026 (n = 7; P < 0.001); (2) reducing the ratio of the coefficients of variation (CV2/ CV1) from 1.49 ± 0.11 (n = 8) to 1.02 ± 0.09 (n = 6; P < 0.05) and 1.11 ± 0.13 (n = 7; P < 0.0) respectively. The results indicate a stimulating effect of Semax on the activity of glutamatergic synapses in neural networks of co-cultures, as well as the ability of the peptide to effectively modulate the short-term plasticity in sensory synapses.

[Optimization of the treatment of anxiety disorders with selank]

AIM

To compare the efficacy and tolerability of monotherapy with phenazepam to complex treatment with the peptide preparation selank and phenazepam in patients with anxiety disorders.

MATERIAL AND METHODS

Authors explored the anxiolytic effect and tolerability of monotherapy with phenazepam (30 patients) and complex treatment with selank and phenazepam (40 patients) in anxiety-phobic, hypochondriac and somatoform disorders (ICD-10 items F40.2-9, F41.1-9, F45.0-2). Therapeutic effect was assessed clinically and with HDRS, CGI and Spilberger scales. Tolerability was evaluated using the UKU scale. Stroop test and verbal fluency test were used. Quality of life was assessed with the SF-36.

RESULTS

The positive effect of phenazepam was achieved earlier in the optimization of treatment with selank on HDRS. The combined treatment decreased the level of undesirable side-effects of phenazepam (attention and memory impairment, asthenia, sedation, increase in sleep duration, sexual disturbances, emotional indifference and orthostatism) during the course of treatment and after the tranquilizer withdrawal. Taken together, the therapeutic efficacy and reduction of side-effects had a positive impact on the quality-of-life of the patients treated with selank as add-on to phenazepam.

CONCLUSION

The results extend therapeutic possibilities of treatment of anxietyspectrum disorders with the combination of benzodiazepine tranquilizers and selank.

[Peptide Regulation of Metabolic Processes under Hypercholesterinemia Conditions of an Organism]

The participation of short glyproline peptides in regulating the metabolic processes of the body has been established. Experimental hypercholesterolemia and the development of metabolic syndrome in rats was caused by including foods with excess animal fat and carbohydrates in the diet, which eventually led to increased levels of cholesterol, triglycerides, and the atherogenic lipoproteins; hypercoagulation; and increased blood sugar. It was noted that glyprolines with different structures possess a unique combined effect on fat and carbohydrate metabolism, normalizing the characteristics of the lipid profile and blood sugar and protecting the organisms of animals from increased blood clotting. The idea of peptide regulation of the hemostatic system and metabolism of fats and carbohydrates in the development of metabolic syndrome was formulated.

Proteolysis of His-Phe-Arg-Trp-Pro-Gly-Pro in the blood and brain of rats in vivo

The kinetics of the content of His-Phe-Arg-Trp-Pro-Gly-Pro (ACTH (6-9)PGP) and its hydrolysis products in the blood and brain of rats in the case of intranasal administration and intravenous injection of tritiated ACTH(6-9)PGP was studied. The parameters of bioavailability of ACTH(6-9)PGP administered intranasally were higher, indicating certain prospects in the intranasal application in clinical practice. We also found that the factor that determines ACTH(6-9)PGP proteolysis in experiments both in vivo and in vitro is aminopeptidases. The main products of ACTH(6-9)PGP during its metabolism in rats are short peptides and amino acids.

Doxorubicin causes transient activation of protein poly(ADP-ribosyl)ation in H9c2 cardiomyocytes

Possible involvement of the system of protein poly(ADP-ribosyl)ation in the mechanisms of cardiotoxicity of doxorubicin, one of the most frequently used anticancer drug, was studied in cultures of cardiomyocytes H9c2. The treatment of H9c2 cells with doxorubicin (1 µM) led to a transient (after 6 h of incubation) increase in the nuclear level of poly(ADP-ribosyl)ated proteins. The observed data indirectly indicate the development of genotoxic stress in the doxorubicin-treated cells, probably caused by the stimulatory effects of doxorubicin and its metabolites on the production of reactive oxygen and nitrogen species.

Effects of Glyprolines on DNA Synthesis and Free Radical Oxidation in Mouse Gastric Mucosa Under Physiological Conditions and During Therapy with Oral Non-Steroid Anti-Inflammatory Drugs

Studies by (3)H-thymidin autoradiography showed that injections of Pro-Gly-Pro and Arg-Gly-Pro peptides caused no changes in the DNA synthesis processes in the gastric mucosa. Both peptides induced a reduction of free radical oxidation activity, which was shown by chemiluminescence. Indomethacin induced lesions in the gastric mucosa, triggered oxidative stress, and reduced proliferative activity. Injection of Pro-Gly-Pro peptide before indomethacin corrected disorders in oxidative status and normalized DNA synthesis. Preinjection of Arg-Gly-Pro led to enlargement (by 4.6 times) of the focus of lesions in animals treated by indomethacin and augmented oxidative stress.

[The selective toxic effect of dialdehyde derivatives of the pyrimidine nucleosides on human tumor cells]

The impact of a number of synthetic nucleoside derivatives on the growth and survival of cultured human ovarian tumor cells (line SKOV-3) and normal human lung fibroblasts was investigated. It was shown that the dialdehyde derivatives of uridine, 1-β-D-eritrofuranozyl uracil and 3'-O-β-D-ribofuranosyl-2'-deoxythymidine, in contrast to their unoxidized counterparts, exert marked toxic effect on SKOV-3 cells. Cultured human fibroblasts were less susceptible to the damaging effect of the dialdehyde nucleosides. The dialdehyde derivative of 1-β-D-eritrofuranozyl uracil demonstrated greatest differences in the cytotoxic effect on these cultures: inhibition of tumor SKOV-3 cells growth on 50% or more was achieved at the concentrations of this compound ten times lower than in the case of normal fibroblasts.