Participation of cAMP-Mediated Signaling Transduction in the Regulation of the Secretory Function of Neuroglia during Ethanol-Induced Neurodegeneration.

We studied the involvement of cAMP and PKA in the regulation of the secretion of neurotrophic growth factors by macro-and microglial cells in the model of ethanol-induced neurodegeneration in vitro and in vivo. The stimulating role of cAMP in the secretion of neurotrophins by intact astrocytes and oligodendrocytes was shown, while PKA does not participate in this process. On the contrary, the inhibitory role of cAMP (implemented via PKA activation) in the production of neurogenesis stimulators by microglial cells under conditions of optimal vital activity was found. Under the influence of ethanol, the role of cAMP and PKA in the production of growth factors by macroglial cells was considerably changed. The involvement of PKA in the cAMP-dependent signaling pathways and inversion of the role of this signaling pathway in the implementation of the neurotrophic secretory function of astrocytes and oligodendrocytes, respectively, directly exposed to ethanol in vitro were noted. Long-term exposure of the nervous tissue to ethanol in vivo led to the loss of the stimulating role of cAMP/PKA signaling on neurotrophin secretion by macroglial cells without affecting its inhibitory role in the regulation of this function in microglial cells.

Psychopharmacological Effects of Stimulation of the Functions of Neural Stem Cells by STAT3 Inhibitor under Conditions of Modeled Ethanol-Induced Encephalopathy.

The psychopharmacological effects of a stimulator of functions of progenitor cells of the nervous tissue STAT3 inhibitor (STAT3 Inhibitor XIV, LLL12) were studied under conditions of modeled alcoholic encephalopathy in C57BL/6 mice. The pharmacological agent corrected the parameters of exploratory behavior (characterizing predominantly cognitive activity) in the experimental animals at the late terms of observation. At the same time, the reproducibility of the conditioned passive avoidance response developed at the beginning of the course STAT3 inhibitor administration decreased. These effects developed against the background of a significant increase in the content of neural stem cells and their proliferative activity in the paraventricular zone of the brain.

The Role of MARK ERK1/2 and p38 in Regulation of Functions of Neural Stem Cells and Neuroglia under Conditions of ß-Amyloid-Induced Neurodegeneration.

The role of ERK1/2 and p38 in the realization of the growth potential of neural stem cells and secretion of neurotrophic growth factors by glial cells was studied using in vitro model of ß-amyloid-induced neurodegeneration. It was shown that amyloid-ß fragment 25-35 significantly inhibits the cell cycle progression of neural stem cells against the background of stimulation of their differentiation and reduced production of growth factors by neuroglia. The inhibitory role of ERK1/2 and p38 in relation to the proliferative activity of neural stem cells and the secretory activity of glial elements was revealed. ERK1/2 and p38 inhibitors increased proliferation of progenitor cells of the nervous tissue and reduced the intensity of their specialization, as well as stimulated production of growth factors by neuroglial cells under conditions of simulated ß-amyloid-induced neurodegeneration.

The Role of JAK and STAT3 in Regulation of Secretory Function of Neuroglial Cells of Different Types in Ethanol-Induced Neurodegenerationt.

The effects of JAK and STAT3 inhibitors on the production of neurotrophic growth factors by different types of neuroglial cells were studied under conditions of in vitro and in vivo models of ethanol-induced neurodegeneration. It was shown that these signaling molecules do not participate in the secretion of neurotrophins by intact astrocytes and oligodendrocytes. The inhibitory role of JAK in the regulation of this function of microglial cells was revealed. We also revealed significant changes in the role of JAK and the presence of STAT3 specifics within the framework of JAK/STAT signaling in the production of growth factors by various glial elements under the influence of ethanol. Neurodegeneration modeled in vitro led to the appearance of a "negative" effect of STAT3 on the production of neurogenesis stimulants by all types of glial cells. Moreover, the role of STAT3 in oligodendrocytes and microglial cells generally corresponded to that of JAK/STAT signaling. In astrocytes, only selective blockade of STAT3 (but not JAK) led to stimulation of their function. In mice subjected to prolonged peroral alcoholization, the neuroglial responses to the pharmacological regulation of JAK/STAT signaling were different. An inversion of the role of JAK and STAT3 in the production of neurotrophins by oligodendrocytes was noted. In addition, JAK inhibitor did not stimulate secretory function of microglial cells under conditions of prolonged exposure to ethanol in vivo.

Role of JNK in the Regulation of Xenobiotic Metabolizing Function of Hepatocytes.

We studied the role of JNK in the regulation of the metabolism of xenobiotic venlafaxine by liver cells under in vitro conditions. The inhibitory role of this protein kinase in the biotransformation of this psychotropic agent by hepatocytes was demonstrated. JNK inhibitor added to the liver homogenate containing antidepressant enhanced and accelerated the formation of the only pharmacologically active venlafaxine metabolite O-desmethylvenlafaxine in the cell suspension. The results show the promise of studying modifiers of activity of intracellular signaling molecules (in particular, mitogen-activated protein kinases) to develop a fundamentally new approach to control the transformation of xenobiotics and to create a new class of pharmaceutical, target regulators of drugs metabolism.

Gut Microbiota-Derived Metabolites in Colorectal Cancer: The Bad and the Challenges.

Accumulating evidence from studies in humans and animal models has elucidated that gut microbiota, acting as a complex ecosystem, contributes critically to colorectal cancer (CRC). The potential mechanisms often reported emphasize the vital role of carcinogenic activities of specific pathogens, but in fact, a series of metabolites produced from exogenous dietary substrates or endogenous host compounds occupy a decisive position similarly. Detrimental gut microbiota-derived metabolites such as trimethylamine-N-oxide, secondary bile acids, hydrogen sulfide and N-nitroso compounds could reconstruct the ecological composition and metabolic activity of intestinal microorganisms and formulate a microenvironment that opens susceptibility to carcinogenic stimuli. They are implicated in the occurrence, progression and metastasis of CRC through different mechanisms, including inducing inflammation and DNA damage, activating tumorigenic signaling pathways and regulating tumor immunity. In this review, we mainly summarized the intimate relationship between detrimental gut microbiota-derived metabolites and CRC, and updated the current knowledge about detrimental metabolites in CRC pathogenesis. Then, multiple interventions targeting these metabolites for CRC management were critically reviewed, including diet modulation, probiotics/prebiotics, fecal microbiota transplantation, as well as more precise measures such as engineered bacteria, phage therapy and chemopreventive drugs. A better understanding of the interplay between detrimental microbial metabolites and CRC would hold great promise against CRC.

Role of MAPK ERK1/2 and p38 in the Regulation of Secretory Functions of Different Populations of Neuroglia in Ethanol-Induced Neurodegeneration.

We studied the participation of ERK1/2 and p38 in secretion of neurotrophic growth factors by various types of neuroglia under conditions of in vitro and in vivo modeled ethanol-induced neurodegeneration. The inhibitory role of these protein kinases in the production of neurotrophins by intact astrocytes and the absence of their participation in the regulation of functions of oligodendrocytes and microglial cells were shown. Under conditions of ethanol neurotoxicity, the role of ERK1/2 and p38 in the production of growth factors by glial elements was significantly changed. Neurodegeneration modeled in vitro led to inversion of the role of both protein kinases in the secretion of neurotrophins by astroglia and inhibition of the cytokine-synthesizing function of oligodendrocytes and microglial cells by ERK1/2 and p38. In mice receiving ethanol per os for a long time (as well as in cells in vitro exposed to ethanol), mitogen-activated kinases stimulated the function of astrocytes and inhibited the production of growth factors by microglial cells. At the same time, chronic alcoholization was accompanied by the appearance of the stimulating role of ERK1/2 and p38 in the implementation of the secretory function by oligodendrocytes.

Epidermal Growth Factor-gold Nanoparticle Conjugates-induced Cellular Responses: Effect of Interfacial Parameters between Cell and Nanoparticle.

The original activity of epidermal growth factor (EGF) is to promote cell growth or block their apoptosis. However, its activity changes to proapoptotic, completely opposite to the original one, upon conjugation to nanoparticles. We have recently identified that this unique activity conversion was mediated by the confinement of EGF receptor (EGFR) within membrane rafts and signal condensation therein. In this study, we investigated the effect of interfacial parameters between the EGF molecule immobilized at the nanoparticle surface and the cell-surface membrane receptors and analyzed how their interactions were transduced to downstream signaling leading to apoptotic responses. We also studied the cell-type selective apoptotic responses and compared them with EGFR expression level to demonstrate the potential of the nanoparticle conjugate as a new type of anti-cancer drug activating EGFR rather than conventional blocking approaches.

Peculiarities of the Involvement of MAPKS ERK1/2 and р38 in the Implementation of the Functions of Neural Stem Cells and Neuronal Committed Precursors in Ethanol-Induced Neurodegeneration.

We studied the peculiarities of the participation of ERK1/2 and р38 in regulation of various types of progenitor cells of the nervous tissue under conditions of ethanol-induced neurodegeneration modeled in vitro and in vivo. The stimulating role of these signaling molecules in the realization of the growth potential of intact multipotent neural stem cells and committed neuronal precursors (clonogenic PSA-NCAM+ cells) was demonstrated. In vitro exposure to neurotoxic doses of ethanol led to the loss of the specified role of ERK1/2 and p38 in the cell cycle regulation. Inversion of the role of both studied MAP-kinases in determining the proliferation status of neural stem cells after long-term administration of ethanol to experimental animals was revealed. In committed neuronal precursors, this inversion (inhibition of mitotic activity instead of activation) was revealed only for ERK1/2. In mice exposed to chronic alcoholization, ERK1/2 no longer participated in the process of specialization of both types of regeneration-competent cells of the nerve tissue. The revealed fundamental difference between the functions of ERK1/2 and p38 in the cell cycle regulation in neural stem cells and committed neuronal precursors under optimal conditions and during ethanol-induced neurodegeneration does not allow drawing definite conclusions about the prospect of using modifiers of their activity for the therapy for alcohol-related CNS pathologies.

Changes in Proteome of Fibroblasts Isolated from Psoriatic Skin Lesions.

The dermal fibroblasts are in constant contact with the cells of the immune system and skin epidermis. Therefore, they are essential for the development of lesions in psoriasis. The aim of this study was to assess the changes in the proteomic profile of fibroblasts in the dermis of psoriasis patients, and to discuss the most significant changes and their potential consequences. The proteomic results indicate that fibroblast dysfunction arises from the upregulation of proinflammatory factors and antioxidant proteins, as well as those involved in signal transduction and participating in proteolytic processes. Moreover, downregulated proteins in psoriatic fibroblasts are mainly responsible for the transcription/translation processes, glycolysis/ adenosine triphosphate synthesis and structural molecules. These changes can directly affect intercellular signaling and promote the hyperproliferation of epidermal cells. A better understanding of the metabolic effects of the proteomic changes observed could guide the development of new pharmacotherapies for psoriasis.

The inhibitory role of Chinese materia medica in cardiomyocyte apoptosis and underlying molecular mechanism.

Apoptosis is an evolutionarily conserved suicide process. It plays critical roles in the development and homeostasis of cardiac tissues. However, excessively stimulated apoptotic activity induced by a myriad of deleterious stimuli can result in too much cardiomyocyte death. The regenerative potential of the adult cardiomyocytes is limited. The cardiomyocyte loss cannot be compensated by efficient cell proliferation. It inevitably leads to various heart diseases. Therefore, the inhibition of cardiomyocyte apoptosis is an important therapeutic strategy for heart diseases. Chinese materia medica (CMM) has more than 2000 years of history and provides effective adjuvant therapeutic strategies for heart disease at the clinical level. The mechanisms underlying the beneficial effects of CMM on heart diseases have been a major focus of recent research. Interestingly, it has been demonstrated that CMM can up-regulate the levels of anti-apoptotic proteins and down-regulate the levels of pro-apoptotic proteins to inhibit apoptotic activity, thereby suppressing cardiomyocyte apoptosis in response to harmful stimuli. The inhibitory effects of CMM on apoptotic activity are mediated by the transduction of intracellular signaling. In this review, we summarize and discuss current findings on the roles and mechanisms of CMM in cardiomyocyte apoptosis.

Strategy of Pharmacological Regulation of Intracellular Signal Transduction in Regeneration-Competent Cells.

The study focuses on the development of principally novel priority-oriented healthcare strategy - targeted therapy in regenerative medicine known as Strategy of Pharmacological Control over Intracellular Signal Transduction in Regeneration-Competent Cells. It implies selective action of promising drugs on specific key elements in the signaling cascade responsible for functional activity of various progenitor cells (including stem cells) and elements of tissue microenvironment. The results of pioneer studies are described that were aimed on revealing the peculiarities in signal transduction and the role of distinct signaling molecules (the potential targets) in the control of cell cycle and other functions of progenitor elements and regulatory cells of different types. The models of some pathological states were employed to demonstrate the possibility of effective implementation of the advanced pharmacotherapeutic concept. The developed theoretical and applied platform can be used to launch synthesis of principally novel preparations with regenerative activity.

Model-based control of the temporal patterns of intracellular signaling in silico.

The functions of intracellular signal transduction systems are determined by the temporal behavior of intracellular molecules and their interactions. Of the many dynamical properties of the system, the relationship between the dynamics of upstream molecules and downstream molecules is particularly important. A useful tool in understanding this relationship is a methodology to control the dynamics of intracellular molecules with an extracellular stimulus. However, this is a difficult task because the relationship between the levels of upstream molecules and those of downstream molecules is often not only stochastic, but also time-inhomogeneous, nonlinear, and not one-to-one. In this paper, we present an easy-to-implement model-based control method that makes the target downstream molecule to trace a desired time course by changing the concentration of a controllable upstream molecule. Our method uses predictions from Monte Carlo simulations of the model to decide the strength of the stimulus, while using a particle-based approach to make inferences regarding unobservable states. We applied our method to in silico control problems of insulin-dependent AKT pathway model and EGF-dependent Akt pathway model with system noise. We show that our method can robustly control the dynamics of the intracellular molecules against unknown system noise of various strengths, even in the absence of complete knowledge of the true model of the target system.

XB130 translocation to microfilamentous structures mediates NNK-induced migration of human bronchial epithelial cells.

Cigarette smoking contributes to the pathogenesis of chronic obstructive pulmonary disease and lung cancer. Nicotine-derived nitrosamine ketone (NNK) is the most potent carcinogen among cigarette smoking components, and is known to enhance migration of cancer cells. However, the effect of NNK on normal human bronchial epithelial cells is not well studied. XB130 is a member of actin filament associated protein family and is involved in cell morphology changes, cytoskeletal rearrangement and outgrowth formation, as well as cell migration. We hypothesized that XB130 mediates NNK-induced migration of normal human bronchial epithelial cells. Our results showed that, after NNK stimulation, XB130 was translocated to the cell periphery and enriched in cell motility-associated structures, such as lamellipodia, in normal human bronchial epithelial BEAS2B cells. Moreover, overexpression of XB130 significantly enhanced NNK-induced migration, which requires both the N- and C-termini of XB130. Overexpression of XB130 enhanced NNK-induced protein tyrosine phosphorylation and promoted matrix metalloproteinase-14 translocation to cell motility-associated cellular structures after NNK stimulation. XB130-mediated NNK-induced cell migration may contribute to airway epithelial repair; however, it may also be involved in cigarette smoking-related chronic obstructive pulmonary disease and lung cancer.

REM Sleep Regulating Mechanisms in the Cholinergic Cell Compartment of the Brainstem.

Rapid eye movement (REM) sleep is a highly evolved yet paradoxical behavioral state (highly activated brain in a paralyzed body) in mammalian species. Since the discovery of REM sleep and its physiological distinction from other sleep states1, a vast number of studies in neurosciences have been dedicated toward understanding the mechanisms and functions of this behavioral state. Collectively, studies have shown that each of the physiological events that characterize the behavioral state of REM sleep is executed by distinct cell groups located in the brainstem. These cell groups are discrete components of a widely distributed network, rather than a single REM sleep center. The final activity within each of these executive cell groups is controlled by the ratio of cholinergic neurotransmission emanating from the pedunculopontine tegmentum (PPT) to aminergic neurotransmission emanating from the locus coeruleus (LC) and raphe nucleus (RN). In this review, we summarize the most recent findings on the cellular and molecular mechanisms in the PPT cholinergic cell compartment that underlie the regulation of REM sleep. This up-to-date review should allow clinicians and researchers to better understand the effects of drugs and neurologic disease on REM sleep.

The New Neurobiology of Depression

Recent basic and clinical studies demonstrate a major role for neural plasticity in the etiology and treatment of depression and stress-related illness. The neural plasticity is reflected both in the birth of new cell in the adult brain (neurogenesis) and the death of genetically healthy cells(apoptosis) in the response to the individual's interaction with the environment. The neural plasticity includes adaptations of intracellular signal transduction pathway and gene expression, as well as alterations in neuronal morphology and cell survival. At the cellular level, repeated stress causes shortening and debranching of dendrite in the CA3 region of hippocampus and suppress neurogenesis of dentate gyrus granule neurons. At the molecular level, both form of structural remodeling appear to be mediated by glucocorticoed hormone working in concert with glutamate and N-methyl-D-aspartate(NMDA) receptor, along with transmitters such as serotonin and GABA-benzodiazepine system. In addition, the decreased expression and reduced level of brain-derived neurotrophic factor(BDNF) could contribute the atrophy and decreased function of stress-vulnerable hippocampal neurons. It is also suggested that atrophy and death of neurons in the hippocampus, as well as prefrontal cortex and possibly other regions, could contribute to the pathophysiology of depression. Antidepressant treatment could oppose these adverse cellular effects, which may be regarded as a loss of neural plasticity, by blocking or reversing the atrophy of hippocampal neurons and by increasing cell survival and function via up-regulation of cyclic adenosine monophosphate response element-binding proteins(CREB) and BDNF. In this article, the molecular and cellular mechanisms that underlie stress, depression, and action of antidepressant are precisely discussed.

Intracellular signal transduction of interleukin-6 production bylipopolysaccharide-stimulated fibroblasts / 대한내과학회지

OBJECTIVES: Stimulation of cell results in a variety of early biochemical events, known as signal transduction pathway and ultimately leads to final outcome like cell proliferation or cytokine production. The intracellular signal transduction pathway of IL-6 production by LPS stimulated fibroblast is not well defined. In present study, we investigated what signal transduction pathway is involved in IL-6 production. METHODS: We examined the effects of various inhi bitors of signal transduction pathway including pertussis toxin, cholera toxin, genistein, indomethacin, EDTA, nife dpine, sphingosine, staurosporine, and H8 on the produc tion of IL-6 by human fetal fibroblast MRC-5 after stimulation with LPS. IL-6 was measured by bioassay in supernatant of LPS stimulated fibroblast MRC-5 after pretreatment with inhibitors. RESULTS: Calcium inhibitor (EDTA) and protein kinase inhibitor (staurosporine) reduced IL-6 production by LPS stimulated fibroblast. Protein tyrosine kinase inhibitor(Genistein) and PKC inhibitor(sphingosine) had no influence on IL-6 production. Cholera toxin and pro staglandin inhibitor (indomethacin) led to increase in IL-6 production by LPS stimulated fibroblasts. CONCLUSION:: These results suggest that G protein associated receptors, through the calcium dependent pathway, are working in IL-6 production by LPS stim ulated fibroblasts.