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Intracellular Pathways (intracellular + pathway)
Selected AbstractsBipolar disorder: candidate drug targets,MOUNT SINAI JOURNAL OF MEDICINE: A JOURNAL OF PERSONALIZED AND TRANSLATIONAL MEDICINE, Issue 3 2008Carlos A. Zarate Jr Abstract Current pharmacotherapy for bipolar disorder is generally unsatisfactory for a large number of patients. Even with adequate modern bipolar pharmacological therapies, many afflicted individuals continue to have persistent mood episode relapses, residual symptoms, functional impairment, and psychosocial disability. Creating novel therapeutics for bipolar disorder is urgently needed. Promising drug targets and compounds for bipolar disorder worthy of further study include both systems and intracellular pathways and targets. Specifically, the purinergic system, the dynorphin opioid neuropeptide system, the cholinergic system (muscarinic and nicotinic systems), the melatonin and serotonin [5-hydroxytryptamine receptor 2C] system, the glutamatergic system, and the hypothalamic-pituitary adrenal axis have all been implicated. Intracellular pathways and targets worthy of further study include glycogen synthase kinase-3 protein, protein kinase C, and the arachidonic acid cascade. Mt Sinai J Med 75:225,246, 2008. © 2008 Mount Sinai School of Medicine [source] Purinergic activation of a leak potassium current in freshly dissociated myocytes from mouse thoracic aortaACTA PHYSIOLOGICA, Issue 2 2009S. Hayoz Abstract Aim:, Exogenous ATP elicits a delayed calcium-independent K+ current on freshly isolated mouse thoracic aorta myocytes. We investigated the receptor, the intracellular pathway and the nature of this current. Methods:, The patch-clamp technique was used to record ATP-elicited delayed K+ current in freshly dissociated myocytes. Results:, ATP-elicited delayed K+ current was not inhibited by a ,cocktail' of K+ channel blockers (4-AP, TEA, apamin, charybdotoxin, glibenclamide). The amplitude of the delayed K+ current decreased after the reduction of extracellular pH from 7.4 to 6.5. These two characteristics suggest that this current could be carried by the TASK subfamily of ,twin-pore potassium channels' (K2P). Purinergic agonists including dATP, but not ADP, activated the delayed K+ current, indicating that P2Y11 is the likely receptor involved in its activation. The PKC activator phorbol ester 12,13-didecanoate stimulated this current. In addition, the PKC inhibitor Gö 6850 partially inhibited it. Real-time quantitative PCR showed that the genes encoding TASK-1 and TASK-2 are expressed. Conclusion:, Our results indicate that blocker cocktail-insensitive delayed K+ current in freshly dissociated aortic myocytes is probably carried by the TASK subfamily of twin-pore channels. [source] Increase of MCP-1 (CCL2) in myelin mutant Schwann cells is mediated by MEK-ERK signaling pathwayGLIA, Issue 8 2008Stefan Fischer Abstract Macrophages are critically involved in the pathogenesis of genetically caused demyelination, as it occurs in inherited demyelinating neuropathies. On the basis of the observation that upregulation of the Schwann cell-derived chemokine MCP-1 (CCL2) is a pathologically relevant mechanism for macrophage activation in mice heterozygously deficient for the myelin component P0 (P0+/,), we posed the question of the intracellular signaling cascade involved. By using western blot analysis of peripheral nerve lysates the MAP-kinases extracellular signal-regulated kinase 1/2 (ERK1/2) and MAP kinase/ERK kinase 1/2 (MEK1/2) showed an early and constantly increasing activation in P0 mutants. Furthermore, in nerve fibers from the P0+/, mutants, Schwann cell nuclei were much more often positive for phosphorylated ERK1/2 than in nerve fibers from wild type mice. In vitro experiments using the MEK1/2-inhibitor CI-1040 decreased ERK1/2-phosphorylation and MCP-1 expression in a Schwann cell-derived cell line. Finally, systemic application of CI-1040 lead to a decreased ERK1/2-phosphorylation and substantially reduced MCP-1-production in peripheral nerves of P0+/, mutant mice. Our study identifies MEK1/2-ERK1/2 signaling as an important intracellular pathway that connects the Schwann cell mutation with the activation of pathogenetically relevant macrophages in the peripheral nerves. These findings may have important implications for the treatment of inherited peripheral neuropathies in humans. © 2008 Wiley-Liss, Inc. [source] PKC-,-dependent cytosol-to-membrane translocation of pendrin in rat thyroid PC Cl3 cellsJOURNAL OF CELLULAR PHYSIOLOGY, Issue 1 2008A. Muscella We studied the expression and the hormonal regulation of the PDS gene product, pendrin, which is, in thyrocytes, responsible for the iodide transport out of the cell. We show that PC Cl3 cells, a fully differentiated thyroid cell line, grown without TSH and insulin, express very low level of PDS mRNA; such expression is greatly increased after stimulation with insulin or TSH. 125I pre-loaded cells showed an 125I efflux accelerated in chloride-containing buffer with respect to chloride-free buffer, suggesting that this efflux is chloride dependent. By immunoblotting, pendrin was found in agonists-stimulated cells, whereas it was barely detectable in un-stimulated cells. An increase in both PDS mRNA and protein was also obtained using phorbol ester PMA, or using 8-Br-cAMP and forskolin. Stimulation with insulin (1 µg/ml; 0,40 min) provoked the cytosol-to-membrane translocation of pendrin and a decrease of intracellular I, content in 125I pre-loaded cells. Insulin- or PMA-treated cells also showed a cytosol-to-membrane translocation of PKC-, and -,. Inhibition of both PKC-, and -, activities by GF109203X blocked pendrin translocation, whilst the inhibition of PKA did not. The selective inhibition of PKC-, by rottlerin did not affect the insulin-provoked translocation of pendrin whilst it was inhibited by a PKC-, translocation inhibitor peptide and also by PKC-, downregulation using the small interfering RNA, thus indicating that such translocation was due to PKC-, activity. In conclusion, our study demonstrates that, in PC Cl3 cells, pendrin expression and localisation are regulated by insulin and influenced by a PKC-,-dependent intracellular pathway. J. Cell. Physiol. 217: 103,112, 2008. © 2008 Wiley-Liss, Inc. [source] Growth Hormone-Releasing Peptide-6 Increases Insulin-Like Growth Factor-I mRNA Levels and Activates Akt in RCA-6 Cells as a Model of Neuropeptide Y NeuronesJOURNAL OF NEUROENDOCRINOLOGY, Issue 11 2005L. M. Frago Abstract Chronic systemic administration of growth hormone (GH)-releasing peptide-6 (GHRP-6), an agonist for the ghrelin receptor, to normal adult rats increases insulin-like growth factor (IGF)-I mRNA and phosphorylated Akt (pAkt) levels in various brain regions, including the hypothalamus. Because neuropeptide Y (NPY) neurones of the arcuate nucleus express receptors for ghrelin, we investigated whether these neurones increase their IGF-I and p-Akt levels in response to this agonist. In control rats, immunoreactive pAkt was practically undetectable; however, GHRP-6 increased p-Akt immunoreactivity in the arcuate nucleus, with a subset of neurones also being immunoreactive for NPY. Immunoreactivity for IGF-I was detected in NPY neurones in both experimental groups. To determine if activation of this intracellular pathway is involved in modulation of NPY synthesis RCA-6 cells, an embryonic rat hypothalamic neuronal cell line that expresses NPY was used. We found that GHRP-6 stimulates NPY and IGF-I mRNA synthesis and activates Akt in this cell line. Furthermore, inhibition of Akt activation by LY294002 treatment did not inhibit GHRP-6 induction of NPY or IGF-I synthesis. These results suggest that some of the effects of GHRP-6 may involve stimulation of local IGF-I production and Akt activation in NPY neurones in the arcuate nucleus. However, GHRP-6 stimulation of NPY production does not involve this second messenger pathway. [source] Hepatocyte growth factor stimulates cell motility in cultures of the striatal progenitor cells ST14AJOURNAL OF NEUROSCIENCE RESEARCH, Issue 5 2003E. Cacci Abstract Hepatocyte growth factor/scatter factor (HGF/SF) is a growth factor with pleiotropic effects on different cell types. It acts as a mitogen and motility factor for many epithelial cells. HGF/SF and its receptor Met are present in the developing and adult mammalian brain and control neuritogenesis of sympathetic and sensory neurons. We report that the striatal progenitor ST14A cells express the Met receptor, which is activated after binding with HGF/SF. The interaction between Met and HGF/SF triggers a signaling cascade that leads to increased levels of c-Jun, c-Fos, and Egr-1 proteins, in agreement with data reported on the signaling events evoked by HGF in other cellular types. We also studied the effects of the exposure of ST14A cells to HGF/SF. By time-lapse photography, we observed that a 24-hr treatment with 50 ng/ml HGF/SF induced modification in cell morphology, with a decrease in cell-cell interactions and increase of cell motility. In contrast, no effect on cell proliferation was observed. To investigate which intracellular pathway is primarily involved we used PD98059 and LY294002, two specific inhibitors of mitogen-activated protein kinase/extracellular signal-regulated kinase (MAP-kinase/ERK-kinase) and phosphoinositide 3-OH kinase (PI3-K), respectively. Cell motility in HGF/SF treated cultures was inhibited by LY294002 but not by PD98059, suggesting that PI3-K plays a key role in mediating the HGF/SF-induced dissociation of ST14A cells. Previous evidence of HGF stimulation of motility in nervous system has been obtained on postmitotic neurons, which have already acquired their specificity. Data reported here of a motogenic response of ST14A cell line, which displays properties of neuronal progenitors, seem of interest because they suggest that HGF could play a role in very early steps of neurogenesis. © 2003 Wiley-Liss, Inc. [source] Actinobacillus actinomycetemcomitans lipopolysaccharide stimulates collagen phagocytosis by human gingival fibroblastsMOLECULAR ORAL MICROBIOLOGY, Issue 3 2008N. Takahashi Introduction:, Collagen phagocytosis by fibroblasts is involved in the intracellular pathway related to collagen breakdown in soft connective tissues. The possible role of lipopolysaccharide (LPS) in regulating this fibroblast function has not been elucidated so we investigated the effect of LPS from Actinobacillus actinomycetemcomitans, a periodontopathic bacterium, on collagen phagocytic activity in human gingival fibroblasts and associated regulatory mechanisms. Methods:, LPS pretreatment stimulated binding of collagen-coated beads to cells and, subsequently, their internalization. Results:, The LPS-activated collagen phagocytic process was enhanced in the presence of the soluble form of CD14 (sCD14) or LPS-binding protein (LBP), while the LPS/LBP treatment activated Akt and induced actin reorganization. Furthermore, these LPS/LBP-induced effects were partially suppressed by adding phosphatidyl-inositol-3 kinase (PI3K) inhibitors. Conclusion:, These results suggest that A. actinomycetemcomitans LPS disturbs the homeostasis of collagen metabolism within gingival tissue by facilitating collagen phagocytosis by gingival fibroblasts, and serum sCD14 and LBP positively regulate the action of LPS. In addition, the PI3K/Akt signaling is thought to partially mediate the LPS/LBP-stimulated collagen phagocytic pathway, which may be dependent on actin cytoskeletal rearrangement. [source] Mechanisms of neurodegeneration in Huntington's diseaseEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 11 2008Joana M. Gil Abstract Huntington's disease (HD) is caused by an expansion of cytosine,adenine,guanine (CAG) repeats in the huntingtin gene, which leads to neuronal loss in the striatum and cortex and to the appearance of neuronal intranuclear inclusions of mutant huntingtin. Huntingtin plays a role in protein trafficking, vesicle transport, postsynaptic signaling, transcriptional regulation, and apoptosis. Thus, a loss of function of the normal protein and a toxic gain of function of the mutant huntingtin contribute to the disruption of multiple intracellular pathways. Furthermore, excitotoxicity, dopamine toxicity, metabolic impairment, mitochondrial dysfunction, oxidative stress, apoptosis, and autophagy have been implicated in the progressive degeneration observed in HD. Nevertheless, despite the efforts of a multidisciplinary scientific community, there is no cure for this devastating neurodegenerative disorder. This review presents an overview of the mechanisms that may contribute for HD pathogenesis. Ultimately, a better understanding of these mechanisms will lead to the development of more effective therapeutic targets. [source] Negative cross-talk between presynaptic adenosine and acetylcholine receptorsEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 1 2006A. V. Shakirzyanova Abstract Functional interactions between presynaptic adenosine and acetylcholine (ACh) autoreceptors were studied at the frog neuromuscular junction by recording miniature end-plate potentials (MEPPs) during bath or local application of agonists. The frequency of MEPPs was reduced by adenosine acting on presynaptic adenosine A1 receptors (EC50 = 1.1 µm) or by carbachol acting on muscarinic M2 receptors (EC50 = 1.8 µm). However, carbachol did not produce the depressant effect when it was applied after the action of adenosine had reached its maximum. This phenomenon implied that the negative cross-talk (occlusion) had occurred between A1 and M2 receptors. Moreover, the occlusion was receptor-specific as ATP applied in the presence of adenosine continued to depress MEPP frequency. Muscarinic antagonists [atropine or 1-[[2-[(diethylamino)methyl)-1-piperidinyl]acetyl]-5,11-dihydro-6H-pyrido [2,3-b][1,4]benzodiazepine-6-one) (AFDX-116)] had no effect on the inhibitory action of adenosine and adenosine antagonists [8-(p -sulfophenyl)theophylline (8-SPT) or 1,3-dipropyl-8-cyclopentylxanthine (DPCPX)] had no effect on the action of carbachol. These data suggested that membrane,delimited interactions did not occur between A1 and M2 receptors. Both carbachol and adenosine similarly inhibited quantal release triggered by high potassium, ionomycin or sucrose. These results indicated a convergence of intracellular pathways activated by M2 and A1 receptors to a common presynaptic effector located downstream of Ca2+ influx. We propose that the negative cross-talk between two major autoreceptors could take place during intense synaptic activity and thereby attenuate the presynaptic inhibitory effects of ACh and adenosine. [source] Dopaminergic signalling in the rodent neonatal suprachiasmatic nucleus identifies a role for protein kinase A and mitogen-activated protein kinase in circadian entrainmentEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 2 2002Irina L. Schurov Abstract The circadian clock of the suprachiasmatic nuclei (SCN) of perinatal rodents is entrained by maternally derived cues. The SCN of neonatal Syrian hamsters express high-affinity D1 dopamine receptors, and the circadian activity,rest cycle of pups can be entrained by maternal injection of dopaminergic agonists. The present study sought to characterize the intracellular pathways mediating dopaminergic signalling in neonatal rodent SCN. Both dopamine and the D1 agonist SKF81297 caused a dose-dependent increase in phosphorylation of the transcriptional regulator Ca2+/cyclic AMP response element (CRE) binding protein (CREB) in suprachiasmatic GABA-immunoreactive (-IR) neurons held in primary culture. The D1 antagonist SCH23390 blocked this effect. Dopaminergic induction of pCREB-IR in GABA-IR neurons was also blocked by a protein kinase A (PKA) inhibitor, 5,24, and by the MAPK inhibitor, PD98059, whereas KN-62, an inhibitor of Ca2+/calmodulin-dependent (CAM) kinase II/IV was ineffective. Treatment with NMDA increased the level of intracellular Ca2+ in the cultured primary SCN neurons in Mg2+ -free medium, but SKF81297 did not. Blockade of CaM kinase II/IV with KN-62 inhibited glutamatergic induction of pCREB-IR in GABA-IR neurons, whereas 5,24 was ineffective, confirming the independent action of Ca2+ - and cAMP-mediated inputs on pCREB. SKF81297 caused an increase in pERK-IR in SCN cells, and this was blocked by 5,24, indicative of activation of MAPK via D1/cAMP. These results demonstrate that dopaminergic signalling in the neonatal SCN is mediated via the D1-dependent activation of PKA and MAPK, and that this is independent of the glutamatergic regulation via Ca2+ and CaM kinase II/IV responsible for entrainment to the light/dark cycle. [source] Facts, fantasies and fun in epithelial physiologyEXPERIMENTAL PHYSIOLOGY, Issue 3 2008C. A. R. Boyd The hallmark of epithelial cells is their functional polarization. It is those membrane proteins that are distributed differentially, either to the apical or to the basal surface, that determine epithelial physiology. Such proteins will include ,pumps', ,channels' and ,carriers', and it is the functional interplay between the actions of these molecules that allows the specific properties of the epithelium to emerge. Epithelial properties will additionally depend on: (a) the extent to which there may be a route between adjacent cells (the ,paracellular' route); and (b) the folding of the epithelium (as, for example, in the loop of Henle). As for other transporters, there is polarized distribution of amino-acid carriers; the molecular basis of these is of considerable current interest with regard to function, including ,inborn errors' (amino-acidurias); some of these transporters have additional functions, such as in the regulation of cell fusion, in modulating cell adherence and in activating intracellular signalling pathways. Collaboration of physiologists with fly geneticists has generated new insights into epithelial function. One example is the finding that certain amino-acid transporters may act as ,transceptors' and play a role as sensors of the extracellular environment that then regulate intracellular pathways controlling cell growth. [source] Effect of 5-lipoxygenase inhibitor MK591 on early molecular and signaling events induced by staphylococcal enterotoxin B in human peripheral blood mononuclear cellsFEBS JOURNAL, Issue 12 2008Chanaka Mendis Staphylococcal enterotoxin B (SEB) has been the focus of a number of studies due to its ability to promote septic shock and a massive impact on the human immune system. Even though symptoms and pathology associated with SEB is well known, early molecular events that lead to lethality are still poorly understood. Our approach was to utilize SEB induced human peripheral blood mononuclear cells (PBMCs) as a prototype module to further investigate the complexity of signaling cascades that may ultimately lead to lethal shock. Our study revealed the activation of multiple divergent intracellular pathways within minutes of SEB induction including components that interconnect investigated pathways. A series of performed inhibitor studies identified a specific inhibitor of 5-LO (MK591), which has the ability to block JNK, MAPK, p38kinase and 5-LO signaling-cascades and drastically reducing the activity of pro-inflammatory cytokine TNF-,. Further evaluation of MK591 utilizing cell proliferation assays in PBMCs, human proximal tubule cells and in vivo studies (monkey) showed a decrease in cell proliferation. The inhibitory effect of MK591 was reconfirmed at a genetic level through the utilization of a set of SEB specific genes. Signaling activities, inhibitor studies, cellular analysis and gene expression analysis in unison illustrated the significance of pathway interconnectors such as 5-LO as well as inhibiting such inter-connectors (using MK591) in SEB induced human PBMCs. [source] Control of oligodendrocyte generation and proliferation by Shp2 protein tyrosine phosphataseGLIA, Issue 12 2010Ying Zhu Abstract Extracellular signals play essential roles in controlling the proliferation and differentiation of oligodendrocyte progenitor cells in the developing central nervous system. However, the intracellular pathways that transduce these extrinsic signals remain to be elucidated. In this study, we showed that conditional ablation of the nonreceptor tyrosine phosphatase Shp2 in Olig1-expressing oligodendrocyte lineage resulted in dramatic reduction in the generation and proliferation of oligodendrocyte progenitor cells in the spinal cord. Maturation and myelination of oligodendrocytes were also compromised in the Shp2 mutants. The deficits in oligodendrocyte development in Shp2 mutants nearly phenocopied those observed in PDGF-A mutants, suggesting that Shp2 is a crucial component in transducing PDGF-A signals in the control of oligodendrocyte proliferation and maturation. © 2010 Wiley-Liss, Inc. [source] Activation of caspase 3 during shear stress-induced neutrophil apoptosis on biomaterialsJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2002Matthew S. Shive Abstract Within the complex environment of an implanted cardiovascular device comprised of dynamic flow and foreign materials, phagocytic neutrophils may be ineffective in combating infection due to cellular responses to shear stress. This may be explained, in part, by our recent reports of apoptosis of biomaterial-adherent leukocytes induced through exposure to shear stress. Here we utilize a rotating disk system to generate physiologically relevant shear stress levels (0,18 dynes/cm2) at the surface of a polyetherurethane urea (PEUU) and investigate neutrophil intracellular pathways involved in shear-induced apoptosis. In situ detection of activated caspases, the enzymatic mediators of the apoptosis cascade, showed qualitatively that these proteases participate in shear-induced apoptosis and are activated in a shear-dependent manner. The involvement of caspase 3 was confirmed through immunoprecipitation and immunoblotting of extracted neutrophil proteins. Comparative studies with neutrophils adherent under static conditions demonstrated time-dependent activation of caspases in TNF-,/cycloheximide-induced apoptosis, for which caspase-3 also was implicated. These findings are the first steps toward elucidation of the mechanisms behind the inappropriate induction of apoptosis by adhesion to biomaterials, which may contribute to the development and persistence of device-related infections. ©2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 163,168, 2002 [source] Inhibitors of the Na+/H+ Exchanger Cannot Prevent Atrial Electrical Remodeling in the GoatJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 4 2004YURI BLAAUW M.D. Introduction: It has been suggested that blockade of the Na+/H+ exchanger (NHE1) can prevent atrial fibrillation (AF)-induced electrical remodeling and the development of AF. Methods and Results: AF was maintained by burst pacing in 10 chronically instrumented conscious goats. Intravenous and oral dosages of two NHE1 blockers (EMD87580 and EMD125021) resulted in plasma levels several magnitudes higher than required for effective NHE1 blockade. Shortening of atrial refractoriness immediately after 5 minutes of AF was not prevented by NHE1 blockade. In remodeled atria, increasing dosages of EMD87580 and EMD125021 did not reverse shortening of the atrial refractory period or reduce the duration of AF episodes. The cycle length during persistent AF also was not affected. Oral pretreatment with EMD87580 (8 mg/kg bid) starting 3 days before AF could not prevent electrical remodeling. After 24 and 48 hours of remodeling, the duration of AF paroxysms was 47 ± 32 seconds and 135 ± 63 seconds compared to 56 ± 17 seconds and 136 ± 52 seconds in placebo-treated animals (P > 0.8), respectively. Conclusion: In the goat model of AF, the Na+/H+ exchanger inhibitors EMD87580 and EMD125021 did not prevent or revert AF-induced electrical remodeling. This indicates that activation of the Na+/H+ exchanger is not involved in the intracellular pathways of electrical remodeling. This does not support the suggestion that blockers of the Na+/H+ exchanger may be beneficial for prevention and treatment of AF. (J Cardiovasc Electrophysiol, Vol. 15, pp. 440-446, April 2004) [source] How does acantholysis occur in pemphigus vulgaris: a critical reviewJOURNAL OF CUTANEOUS PATHOLOGY, Issue 6 2006Alessandro Lanza Background:, Pemphigus vulgaris is a life-threatening autoimmune blistering disease targeting skin and mucous membranes, characterized by disruption of keratinocytes' adhesion termed acantholysis. Today multiple classes of targets are considered to play a role in the genesis of the acantholysis; of these, the classical pemphigus antigens, desmosomal cadherins (desmoglein 1 and 3) are the best characterized and considered as the most important. Additional antigens include the novel epithelial acetylcholine receptors (,9 and pemphaxin). Thus, acantholysis in pemphigus seems to result from a cooperative action of antibodies to different keratinocyte self-antigens, but the mechanisms by which epithelial cleft occurs are not yet clearly understood. In fact, the binding of the autoantibodies to these targets generates a plethora of biological effects due, on one hand, to their direct interference with adhesive function and, on the other, to more complex events involving intracellular pathways that modify proteases activity or calcium metabolism, leading to loss of cell,cell adhesion. [source] Morphine activates Arc expression in the mouse striatum and in mouse neuroblastoma Neuro2A MOR1A cells expressing ,-opioid receptorsJOURNAL OF NEUROSCIENCE RESEARCH, Issue 4 2005Barbara Zió, kowska Abstract Activity-regulated cytoskeleton-associated protein (Arc) is an effector immediate early gene product implicated in long-term potentiation and other forms of neuroplasticity. Earlier studies demonstrated Arc induction in discrete brain regions by several psychoactive substances, including drugs of abuse. In the present experiments, the influence of morphine on Arc expression was assessed by quantitative reverse transcription real-time PCR and Western blotting in vivo in the mouse striatum/nucleus accumbens and, in vitro, in the mouse Neuro2A MOR1A cell line, expressing ,-opioid receptor. An acute administration of morphine produced a marked increase in Arc mRNA and protein level in the mouse striatum/nucleus accumbens complex. After prolonged opiate treatment, tolerance to the stimulatory effect of morphine on Arc expression developed. No changes in the striatal Arc mRNA levels were observed during spontaneous or opioid antagonist-precipitated morphine withdrawal. In Neuro2A MOR1A cells, acute, but not prolonged, morphine treatment elevated Arc mRNA level by activation of ,-opioid receptor. This was accompanied by a corresponding increase in Arc protein level. Inhibition experiments revealed that morphine induced Arc expression in Neuro2A MOR1A cells via intracellular signaling pathways involving mitogen-activated protein (MAP) kinases and protein kinase C. These results lend further support to the notion that stimulation of opioid receptors may exert an activating influence on some intracellular pathways and leads to induction of immediate early genes. They also demonstrate that Arc is induced in the brain in vivo after morphine administration and thus may play a role in neuroadaptations produced by the drug. © 2005 Wiley-Liss, Inc. [source] Emerging role of mitogen-activated protein kinases in peripheral neuropathiesJOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 3 2007Guido Cavaletti Abstract Among the different families of intracellular molecules that can be modulated during cell damage and repair, mitogen-activated protein kinases (MAPKs) are particularly interesting because they are involved in several intracellular pathways activated by injury and regeneration signals. Despite most of the studies have been performed in non-neurological models, recently a causal role for MAPKs has been postulated in central nervous system disorders. However, also in some peripheral neuropathies, MAPK changes can occur and these modifications might be relevant in the pathogenesis of the damage as well as during regeneration and repair. In this review, the current knowledge on the role of MAPKs in peripheral neuropathies will be discussed. [source] Liver fibrosis: searching for cell model answersLIVER INTERNATIONAL, Issue 4 2007Ma. Concepción Gutiérrez-Ruiz Abstract Hepatic stellate cells (HSC) are the principal fibrogenic cell type in the liver. Progress in understanding the cellular and molecular basis for the development and progression of liver fibrosis could be possible by the development of methods to isolate HSC from rodents and human liver. Growth of stellate cells on plastic led to a phenotypic response known as activation, which paralleled closely the response of these cells to injury in vivo. Actually, much of the current knowledge of stellate cell behaviour has been gained through primary culture studies, particularly from rats. Also, different laboratories that have established hepatic stellate cell lines from rats and humans have provided a stable and unlimited source of cells that express specific functions, making them suitable for culture-based studies of hepatic fibrosis. From these in vitro models grew a large body of information characterizing stellate cell activation, cytokine signalling, intracellular pathways regulating liver fibrogenesis, production of extracellular matrix proteins and development of antifibrotic drugs. [source] Intracellular survival pathways in the liverLIVER INTERNATIONAL, Issue 10 2006Tom Luedde Abstract: Recent studies have drawn attention to cytokines as important modulators of hepatocyte cell death during acute and chronic liver disease. Through interaction with cell surface receptors, they activate specific intracellular pathways that influence cell fate in different manners. For example, tumor necrosis factor not only induces proapoptotic signals via the caspase cascade but also activates intracellular survival pathways, namely the nuclear factor (NF)-,B pathway. In this article, we will focus on the function of the NF-,B pathway in liver physiology and pathology. Especially, recent data based on experiments with genetically modified mice will be discussed, which demonstrated important and controversial functions of this pathway e.g. in cytokine-mediated hepatocyte apoptosis, ischemia-reperfusion injury, liver regeneration and the development of hepatocellular carcinoma. Moreover, the role of the interleukin-6 pathway and its possible protective function in the context of liver failure will be summarized. [source] Carbon Monoxide has Antioxidative Properties in the Liver Involving p38 MAP Kinase Pathway in a Murine Model of Systemic InflammationMICROCIRCULATION, Issue 7 2010JÜRGEN BRUGGER Please cite this paper as: Brugger, Schick, Brock, Baumann, Muellenbach, Roewer and Wunder (2010). Carbon Monoxide has Antioxidative Properties in the Liver Involving p38 MAP Kinase Pathway in a Murine Model of Systemic Inflammation. Microcirculation17(7), 504,513. Abstract Objective:, Reactive oxygen species (ROS) are important in the hepatocellular injury process during a systemic inflammation. We examined the role of carbon monoxide (CO) on the hepatic generation of ROS with in-vivo and in-vitro models of systemic inflammation. Methods:, Using a murine model of bilateral hindlimb ischemia-reperfusion (I/R) we examined the effect of CO treatment on hepatic ROS formation, oxidative status, and cell injury. Cultured HUVEC were used to investigate intracellular pathways. Results:, CO treatment reduced hepatic lipid peroxidation, re-established total hepatic glutathione and glutathione disulfide (GSH/GSSG) levels and reduced hepatocellular injury. Inhibition of heme oxygenase (HO) during treatment with CO during hindlimb I/R failed to alter the antioxidant qualities provided by CO. The production of ROS after tumor necrosis factor-, (TNF-,) stimulation in HUVEC was diminished after exposure to CO. Treatment with CO during HO inhibition reduced both ROS formation and cell injury. Inhibiting the p38 MAPK (mitogen-activated protein kinase) pathway with pyridinyl imidazol (SB203580) revealed that the antioxidant potential of CO involved the activation of p38 MAPK. Conclusions:, CO has direct antioxidant potential independently of any HO activity during systemic inflammation. The antioxidant effects afforded by CO involve the activation of the p38 MAPK pathway. [source] Bipolar disorder: candidate drug targets,MOUNT SINAI JOURNAL OF MEDICINE: A JOURNAL OF PERSONALIZED AND TRANSLATIONAL MEDICINE, Issue 3 2008Carlos A. Zarate Jr Abstract Current pharmacotherapy for bipolar disorder is generally unsatisfactory for a large number of patients. Even with adequate modern bipolar pharmacological therapies, many afflicted individuals continue to have persistent mood episode relapses, residual symptoms, functional impairment, and psychosocial disability. Creating novel therapeutics for bipolar disorder is urgently needed. Promising drug targets and compounds for bipolar disorder worthy of further study include both systems and intracellular pathways and targets. Specifically, the purinergic system, the dynorphin opioid neuropeptide system, the cholinergic system (muscarinic and nicotinic systems), the melatonin and serotonin [5-hydroxytryptamine receptor 2C] system, the glutamatergic system, and the hypothalamic-pituitary adrenal axis have all been implicated. Intracellular pathways and targets worthy of further study include glycogen synthase kinase-3 protein, protein kinase C, and the arachidonic acid cascade. Mt Sinai J Med 75:225,246, 2008. © 2008 Mount Sinai School of Medicine [source] Characterization of cis elements of the probasin promoter necessary for prostate-specific gene expression,THE PROSTATE, Issue 9 2010JianFeng Zhang Abstract BACKGROUND The androgen-regulated probasin (PB) promoter has been used extensively to target transgenes to the prostate in transgenic mice; however, limited data exist on the mechanism that dictates prostate-specific gene expression. Tissue-specific gene expression involves synergistic effects among transcription factors associated in a complex bound to cis -acting DNA elements. METHODS Using comprehensive linker scan mutagenesis, enzyme mobility shift and supershift assays, chromatin immunoprecipitation, and transgenic animal studies, we have extensively characterized the prostate-specific PB promoter. RESULTS We identified a series of nonreceptor transcription factors that are bound to the prostate-specific rat PB promoter. These factors include several ubiquitously distributed proteins known to participate in steroid receptor-mediated transcription. In addition, we identified two tissue-specific DNA elements that are crucial in directing prostate-specific PB expression, and confirmed the functional importance of both elements in transgenic animal studies. These two elements are functionally interchangeable and can be bound by multiple protein complexes, including the forkhead transcription factor FoxA1, a "pioneer factor" that has a restricted distribution to some cells type that are ectoderm and endoderm in origin. Using transgenic mice, we further demonstrate that the minimal PB promoter region (,244/,96,bp) that encompasses these tissue-specific elements results in prostate-specific gene expression in transgenic mice, contains androgen receptor and FoxA1-binding sites, as well as ubiquitous transcription factor binding sites. CONCLUSION We propose that these sequence-specific DNA-binding proteins, including tissue-restricted and ubiquitous factors, create the first level of transcriptional control, which responds to intracellular pathways that directs prostate-specific gene expression. Prostate 70: 934,951, 2010. © 2010 Wiley-Liss, Inc. [source] Entorhinal Cortex Lesion in the Mouse Induces Transsynaptic Death of Perforant Path Target NeuronsBRAIN PATHOLOGY, Issue 3 2004Adam D. Kovac Entorhinal cortex lesion (ECL) is a well described model of anterograde axonal degeneration, subsequent sprouting and reactive synaptogenesis in the hippocampus. Here, we show that such lesions induce transsynaptic degeneration of the target cells of the lesions pathway in the dentate gyrus. Peaking between 24 and 36 hours postlesion, dying neurons were labeled with DeOlmos silver-staining and antisera against activated caspase 3 (CCP32), a downstream inductor of programmed cell death. Within caspase 3-positive neurons, fragmented nuclei were co-localized using Hoechst 33342 staining. Chromatin condensation and nuclear fragmentation were also evident in semithin sections and at the ultrastructural level, where virtually all caspase 3-positive neurons showed these hallmarks of apoptosis. There is a well-described upregulation of the apoptosis-inducing CD95/L system within the CNS after trauma, yet a comparison of caspase 3-staining patterns between CD95 (lpr)- and CD95L (gld)-deficient with non-deficient mice (C57/bl6) provided no evidence for CD95L-mediated neuronal cell death in this setting. However, inhibition of NMD A receptors with MK-801 completely suppressed caspase 3 activation, pointing to glutamate neurotoxicity as the upstream inducer of the observed cell death. Thus, these data show that axonal injury in the CNS does not only damage the axotomized neurons themselves, but can also lethally affect their target cells, apparently by activating glutamate-mediated intracellular pathways of programmed cell death. [source] ,1 -Adrenoceptor effects mediated by protein kinase C , in human cultured prostatic stromal cellsBRITISH JOURNAL OF PHARMACOLOGY, Issue 1 2003A Preston We have investigated the effects of ,1 -adrenoceptor stimulation upon contractility, Ca2+ influx, inositol phosphate production, and protein kinase C (PKC) translocation in human cultured prostatic stromal cells (HCPSC). The ,1 -adrenoceptor selective agonist phenylephrine elicited contractile responses of HCPSC, i.e. a maximal cell shortening of 45±6% of initial cell length, with an EC50 of 1.6±0.1 ,M. The ,1 -adrenoceptor selective antagonists prazosin (1 ,M) and terazosin (1 ,M) both blocked contractions to phenylephrine (10 ,M). The L-type calcium channel blocker nifedipine (10 ,M), and the PKC inhibitors Gö 6976 (1 ,M) and bisindolylmaleimide (1 ,M) also inhibited phenylephrine-induced contractions. Phenylephrine caused a concentration dependent increase in inositol phosphate production (EC50 119±67 nM). This response was blocked by terazosin (1 ,M). Phenylephrine caused the translocation of the PKC , isoform, but not the ,, ,, ,, , or , isoforms, from the cytosolic to the particulate fraction of HCPSC, with an EC50 of 5.7±0.5 ,M. In FURA-2AM (5 ,M) loaded cells, phenylephrine elicited concentration dependent increases in [Ca2+]i, with an EC50 of 3.9±0.4 ,M. The response to phenylephrine (10 ,M) was blocked by prazosin (1 ,M), bisindolymaleimide (1 ,M), and nifedipine (10 ,M). In conclusion, this study has shown that HCPSC express functional ,1 -adrenoceptors, and that the intracellular pathways responsible for contractility may be largely dependent upon protein kinase C activation and subsequent opening of L-type calcium channels. British Journal of Pharmacology (2003) 138, 218,224. doi:10.1038/sj.bjp.0705021 [source] | ||||||||||||||||