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.