[Impairments of rats' behavioral reactions, concentration of corticosterone and expression of cytokine's gene under experimental postviral fatigue].

The aim of the main research was investigated of interaction of neural, endocrine and immune systems under experimental postviral fatigue, behavioral reactions, level of corticosterone, changes of IL-3 and IL-10 gene expression in rats' hypothalamus and INF-α in hypothalamus and spleen were analyzed. It has been shown the decrease of physical activity, increasing of corticosterone's level and gene expression of cytokines after injection of Poly I:C as a model of postviral fatigue. After remedication of Poly I:C increasing of physical activity was shown.

Stress-induced changes in the functional activity of the neuroendocrine system: the modulatory activity of derinat.

Changes in the functional activity of the hypothalamo-hypophyseal-adrenocortical system (HHACS) and hypothalamo-hypophyseal-gonadal system (HHGS) in conditions of different levels of stress and the possibility of correcting them using the native DNA formulation Derinat, which has immunomodulatory properties, were studied. The vectors of changes in hormonal reactions in both systems were found to be independent of the intensity of stress: there were increases in corticosterone levels and decreases in testosterone concentrations in different stress models. Intraperitoneal administration of Derinat at doses of 10 and 50 mg/kg increased HHACS and HHGS activity and reversed the stress-induced reduction in the blood testosterone concentration, which may be evidence that Derinat has stress-protecting effects. Administration of Derinat promoted normalization of stress-induced changes in the production of immunomodulatory cytokines among lymphocyte-activating factors with regulatory influences not only on the functioning of the immune system, but also on the HHACS and HHGS functions.

Activity in the hypothalamo-hypophyseal-adrenocortical system on experimental induction of chronic fatigue syndrome.

Changes in the activity of the hypothalamo-hypophyseal-adrenocortical system (HHACS) were studied in an experimental model of chronic fatigue syndrome induced by i.p. administration of synthetic doublestranded RNA (polyriboinosinic:polyribocytidylic acid, Poly I:C) at a dose of 3 mg/kg. Functional changes in the different components of the HHACS were detected using standard tests with i.p. ACTH or hydrocortisone on the background of cold stress and injections of Poly I:C. Single doses of Poly I:C were followed by the development of impairments to HHACS function, with decreases in the ACTH sensitivity of adrenal cells and suppression of the negative feedback mechanism, resulting in significant decreases in corticosterone concentrations in standard tests with administration of ACTH and hydrocortisone.

[Stress-induced changes in functional activity of the neuro-endocrine system: modulatory action of derinat].

Changes in functional activity of HPA and HPG axes under stress influences of different intensity, and possible ways for their correction by native DNA preparation: derinat, possessing immune modulator effects, were studied. It was shown that the vector of changes in hormone's reactions of both axes did not depend on the intensity of stress influences: different models of stress increased corticosterone level and decreased testosterone level in rats' blood. Intraperitoneal injection of 10 and 50 mg/kg BW doses of Derinat to rats enhanced HPA and HPG axes activity, reversed stress-induced decrease of testosterone concentration in blood, that may indicate a stress-protective effect of derinat. Injection of derinat caused normalizing of stress-induced changes in immunomodulatory cytokines production within Lymphocyte Activating Factors, which regulate not only the immune system functions but also the functions of HPA and HPG axes.

[Activity of hypotnalamic-pituitary-adrenal axis by induction of experimental chronic fatigue syndrom].

Changes in the activity of hypothalamic-pituitary adrenal (HPA) axis were investigated in experimental model of chronic fatigue syndrome (CFS) induced by intraperitoneal administration of synthetic double-stranded RNA (polyriboinosinic: polyribocytidylic acid, Poly I : C) to rats in the dose of 3 mg/kg body weight. In order to reveal functional changes in different links of the HPA axis, standard probes with intraperitoneal administration of ACTH and hydrocortisone against the background of cold stress application and Poly I : C injections were performed. A single injection of Poly I : C led to disordered HPA axis functions which was manifested by decreased sensitivity of the cells in the adrenal gland in response to ACTH, and suppression of the mechanism of negative feedback resulting in significant fall of cortisocterone concentration in standard assays with ACTH and hydrocortisone administration.

[Cellular and molecular mechanisms of interaction between the neuroendocrine and immune systems under chronic fatigue syndrome in experiment].

One of the main mechanisms of chronic fatigue syndrome development involves disturbances of interaction between the immune and neuroendocrine systems. The adequate experimental model for the search of these mechanisms is induction of fatigue in animals via the single intraperitoneal administration of synthetic double-stranded RNA - Poly I : C. Investigation of alterations in cytotoxic and proliferation activities of splenocytcs, the intensity of immunomodulatory cytokines signaling via the sphingomyelin pathways in membrane P2 fraction of the brain cortex, as well as the activity of hypothalamic-pituitary adrenal (HP A) axis in the dynamics of chronic fatigue syndrome in rats has performed. Inhibition of both cytotoxic and proliferative activities of splenocytes during the period of fatigue development has been shown. Priority data concerning the suppression of the activity of neutral sphingomyelinase (nSMase) - the key enzyme of the sphingomyelin cascade - in membranes ofthe cells from the brain cortex on the 3d day after Poly I : C administration to rats have been obtained. It was found that Poly I : C injection to rats led to disturbed HPA axis functions which was manifested by decreased corticosterone concentration in standard functional assays with ACTH and hydrocortisone administration. It is suggested that disturbances in interaction between the immune and neuroendocrine systems during development of chronic fatigue syndrome, including alterations in HPA axis activity, are realized both on the level of changes in the activity of immune-competent cells and immediately on membranes of the brain cells.

Expression of the c-Fos gene in hypothalamic cells and cytotoxic activity of natural killer cells in the spleen of rats after treatment with Cytoxan.

In experiments on rats we studied the effect of cyclophosphamide-containing drug Cytoxan on activation of neurons in hypothalamic structures involved in the regulation of natural killer cell activity in the spleen and changes in cytotoxicity of these cells. Administration of Cytoxan in a dose of 60 mg/kg increased the number of c-Fos-positive cells in the ventromedial hypothalamus and lateral hypothalamic area and reduced interferon-alpha-induced cytotoxic activity of natural killer cells. Our findings attest to the involvement of central mechanisms of regulation of splenic natural killer cells into side effects of Cytoxan.

Production of lymphocyte-activating factors by mouse macrophages during aging and under the effect of short peptides.

Age-specific characteristics of production of lymphocyte-activating factor by mouse peritoneal macrophages and modulation of this production by short synthetic peptides (Vilon, Epithalon, and Cortagen) were studied. The production of lymphocyte-activating factors by macrophages stimulated with lipopolysaccharides in vitro was lower in old animals. The opposite modulating effects of short peptides on the production of lymphocyte-activating factors by resident and lipopolysaccharide-stimulated macrophages in young and old mice were demonstrated for the first time. This is a possible mechanism of immune system dysfunction during aging, which opens new vistas for its correction with short synthetic peptides.

[Interleukin-1 signal transduction in interaction between the nervous and immune systems].

Ligand-receptor interactions of the cytokine Interleukin-1 (IL-1) with its target cells, and further intercellular signal transduction play the key role in manifestation of its biological effects. Peculiarities of IL-1 signaling are determined by its unique structure and the composition of its receptors. The sphingomyelin pathway of IL-1beta signal transduction is one of the principle signal mechanisms providing realization of most, if not all, biological effects of cytokine. This signaling pathway is initiated by activation of the membrane enzyme neutral sphingomyelinase (nSMase), which catalyses the hydrolysis of membrane shingomyelin to the secondary cellular messenger ceramide. It has been established that IL-1beta operation in the CNS involves mechanisms mediated by IL-1 type beta1 receptor and the shingomyeline pathway of cytokine signal transduction into the cell. Type 1 IL-1 receptor is necessary for IL-1-induced activation of nSMase, the key enzyme of the sphingomyelin cascade. Change in nSMase activity in membranes of nerve and immunocompetent cells is the common link in the stress reaction of neuroendocrinal and immune system cells. nSMase activity seems to be a potential target for testing effects of various pharmaceuticals and interventions, while planning strategy of correction of immune system dysfunctions and neuro-immune interaction disturbances.

[The role of glucocorticoid hormones in interleukin-1 signal transduction via the sphingomyelin pathway]. / Rol' gliukokortikoidnykh gormonov v transduktsii signala interleikina-1 po sfingomielinovomu puti.

Interleukin-1 and glucocorticoid hormones are the key transmitters of interaction between the neuroendocrine and immune systems. To study the molecular mechanisms of immunomodulatory effects of Interleukin-1 and glucocorticoid hormones, a search for changes in activity of neutral sphingomyelinase: the main marker of initiation of Interleukin-1beta signal transduction via the sphingomyelin pathway in target cells, was accomplished. The Interleukin-1beta was found to activate neutral sphingomyelinase both in P2 fraction of murine brain cortex and membranes of immune-competent cells. Experimental modifications of endogenous glucocorticoid level in the mouse blood were for the first time shown to induce changes in neutral sphingomyelinase activity in membranes of the cells of the immune and nervous systems. It appears that the sphingomyelinase pathway of Interleukin-1beta signaling might be a possible target for glucocorticoid hormones' immune-modulating effects.

Effects of short peptides on thymocyte blast transformation and signal transduction along the sphingomyelin pathway.

Immunomodulating effects of synthetic peptides Vilon (Lys-Glu), Epithalon (Ala-Glu-Asp-Gly), and Cortagen (Ala-Glu-Asp-Pro) and possible involvement of the sphingomyelin signal transduction pathway in their effects in mouse thymocytes were studied. Vilon produced the most potent comitogenic effect on thymocyte proliferation and modulated comitogenic activity of interleukin-1b. Epithalon was less potent, while Cortagen produced no such effects. Vilon produced a more pronounced stimulatory effect on sphingomyelinase activity in mouse thymocyte membranes compared to Epithalon and Cortagen.

The role of interleukin-1 in stress-induced changes in immune system function.

The cellular-molecular mechanisms of changes in immune system function were studied, including the production of lymphocyte activating factor (LAF) and interleukin-1 (IL-1). the effects of IL-1 on target cells, and subsequent cytokine signal transduction via the sphingomyelin pathway, in different types of stress. These experiments showed that stress of different durations and intensities induced the formation of lymphocyte activating factors by peritoneal macrophages and increased IL-la levels in mouse blood. but led to different changes in the responses of target thymocytes to the committing actions of IL-1beta. which correlated with changes in the level of the humoral immune response. These data coincided with differently-directed stress-induced changes in the activity of membrane-bound neutral sphingomyelinase. the key enzyme in the sphingomyelin cascade, in cerebral cortex membrane fraction P2 from mouse brains. The results obtained here suggest that IL-1 is involved in the physiological mechanisms of stress reactions, operating at the levels of IL-1 production and its biological actions on lymphoid target cells, as well as at the level of cytokine signal transduction via the sphingomyelin pathway in nerve tissue.

The role of neutral sphingomyelinase in interleukin-1beta signal transduction in mouse cerebral cortex cells.

The cytokine interleukin-1 (IL-1) is an important mediator of neuroimmune interactions, though it has not been established precisely how the IL-lbeta signal is transmitted in nerve cells. This study demonstrates the involvement of the sphingomyelin cascade in IL-1beta signal transduction in the P2 membrane fraction of the mouse cerebral cortex. The key role of the membrane enzyme neutral sphingomyelinase in initiating the sphingomyelin signal transduction pathway for this cytokine is supported. The stimulating activity of IL-1beta on sphingomyelinase activity in the P2 fraction of the cerebral cortex was found to be dose-dependent. Studies using this membrane fraction from mice lacking the IL-1 type I receptor due to genomic mutations, along with studies using an IL-1 receptor antagonist. yielded data showing that IL-1beta binding with the type I receptor is a necessary event for activation of neutral sphingomyelinase. The results obtained here lead to the conclusion that the action of IL-1beta in the CNS is mediated by the IL-1 type I receptor and activation of neutral sphingomyelinase as the initiating enzyme of the sphingomyelin cascade.

[Interleukin-1 in realisation of stress-induced changes in functions of the immune system]. / Interleikin-1 v realizatsii stress-indutsirovannykh izmenenii funktsii immunnoi sistemy.

Stress influences of different duration and intensity induce production of a lymphocyte-activating factor (LAF) by murine peritoneal macrophages, and enhancement of Interleukin 1 (IL-1) level in the murine blood, inducing no alterations in the thymocyte reaction to concomitant action of the IL-1 beta which correlates with changes in the value of humoral immune response. The data obtained are in agreement with differently aimed stress-induced alterations in the activity of the membrane neutral sphingomyelinase: the key enzyme of the sphingomyelin cascade, in the membrane P2 fraction of the brain cortex. The IL-1 seems to participate in physiological mechanisms of realisation of stress reactions on the levels of its production and biological action on target cells as well as of the sphingomyelin pathway of its signal transduction in nerve tissue.

[The role of neutral sphingomyelinase in the interleukin-1beta signal transduction in cells of the mouse cerebral cortex]. / Rol' neitral'noi sfingomielazy v transduktsii signala interleikina-1beta v kletkakh kory golovnogo mozga myshei.

Involvement of the sphingomyelin cascade in Interleukin 1 beta (IL-1) signal transduction pathway in membrane fraction P2 of the murine brain cortex, was found. A key role of the membrane enzyme neutral sphingomyelinase (nSMase) in triggering the sphingomyelin pathway for IL-1 beta, was confirmed. The IL-1 beta was shown to activate in a dose-dependent manner nSMase in the P2 fraction of the brain cortex. Employment of both brain cortex membranes from the mice deficient in the type I IL-1 receptor and of IL-1 receptor antagonist made it possible to obtain evidence on the necessity of the IL-1 beta binding to the type I IL-1 receptor for the nSMase activation. It appears that the IL-1 beta effects on the CNS are realized via IL-1 receptor type I and activation of the nSMase as an initiating enzyme of the sphingomyelin cascade.

Activation of neutral sphingomyelinase by IL-1beta requires the type 1 interleukin 1 receptor.

The cytokine interleukin 1beta (IL-1beta) plays an important role in host defence reactions and neuro-immune interactions but it is still not clear which of the two interleukin 1 receptor subtypes is coupled to activation of neutral sphingomyelinase (nSMase) by IL-1beta. To investigate involvement of neutral sphingomyelinase (nSMase) in central IL-1beta effects we used P(2)fractions of brain cerebral cortex from wild-type mice and mice deficient in the type 1 IL-1 receptor. IL-1beta (human, recombinant) was shown to activate, in a dose-dependent manner, nSMase in the P(2)brain fraction of the wild-type mice while in the knock-out mice the stimulatory effect of IL-1beta on nSMase was absent. In the presence of an IL-1 receptor antagonist (IL-1ra), IL-1beta did not activate nSMase either in the cortex of wild-type or knock-out mice. These data suggest that nSMase, a key enzyme of the sphingomyelin signal transduction pathway, might be involved in IL-1beta signalling in the brain and that activation of the enzyme requires the IL-1 receptor type 1.

[Effect of modification of the structure of interleukin-1beta on its physiological activity]. / Vliianie modifikatsii struktury interleikina-1beta na ego physiologicheskuiu aktivnost'.

Modification of the structure of recombinant human IL-1 beta: deletion of the amino acids serine, asparagine, and asparagic acid in position 52-54 in mutant delta SND, led to major changes in its functional activity. Significant reduction of the main IL-1 beta activities: concomitant, pyrogenic and corticotropic ones in the mutant delta SND, suggests the latter to be a partial agonist of IL-1 beta. Nevertheless the reduction in certain parameters of the humoral immune response in mice following administration of the delta SND preparation suggests that, when manifesting its immunomodulatory properties, the delta SND acts as a partial antagonist of the IL-1 beta.

[Physiological analysis of stress-induced changes in the suppressor activity of mouse T-lymphocytes]. / Fiziologicheskii analiz stressindutsirovannogo izmeneniia supressornoi aktivnosti T-limfotsitov u myshei.

Suppressor activity of the T-lymphocytes was studied by means of evaluating the alterations in humoral immune response in the system of adoptive transfer of splenocytes from immunised donors (PFC/106 splenocytes) in mice. Administration of glucocorticoids or stress prior to the immunisation decreased the suppressor activity of the T-lymphocytes and enhanced humoral immune response. In adrenalectomised mice, absence of glucocorticoid hormones in the blood did not prevent normal development of the suppressor functions of the T-lymphocytes. Administration of Interleukin-1 prior to the stress or hydrocortisone administration normalised the T-lymphocytes' functions.