Логістика туризму: комплексний підхід

It is well-established that prostaglandins (PGs) affect tumorigenesis, and evidence indicates that PGs also are important for the reduced food intake and body weight loss, the anorexia–cachexia syndrome, in malignant cancer. However, the identity of the PGs and the PG producing cyclooxygenase (COX) species responsible for cancer anorexia–cachexia is unknown. Here, we addressed this issue by transplanting mice with a tumor that elicits anorexia. Meal pattern analysis revealed that the anorexia in the tumor-bearing mice was due to decreased meal frequency. Treatment with a non-selective COX inhibitor attenuated the anorexia, and also tumor growth. When given at manifest anorexia, non-selective COX-inhibitors restored appetite and prevented body weight loss without affecting tumor size. Despite COX-2 induction in the cerebral blood vessels of tumor-bearing mice, a selective COX-2 inhibitor had no effect on the anorexia, whereas selective COX-1 inhibition delayed its onset. Tumor growth was associated with robust increase of PGE2 levels in plasma – a response blocked both by non-selective COX-inhibition and by selective COX-1 inhibition, but not by COX-2 inhibition. However, there was no increase in PGE2-levels in the cerebrospinal fluid. Neutralization of plasma PGE2 with specific antibodies did not ameliorate the anorexia, and genetic deletion of microsomal PGE synthase-1 (mPGES-1) affected neither anorexia nor tumor growth. Furthermore, tumor-bearing mice lacking EP4 receptors selectively in the nervous system developed anorexia. These observations suggest that COX-enzymes, most likely COX-1, are involved in cancer-elicited anorexia and weight loss, but that these phenomena occur independently of host mPGES-1, PGE2 and neuronal EP4 signaling.Funding Agencies|Swedish Cancer Foundation||Swedish Research Council||Swedish Brain Foundation||</p

Distribution and pathophysiological role of amyloid precursor protein and presenilin 1 : characterization in rats and in vitro studies on the pathogenic arctic mutation

Alzheimer's disease is the most common form of dementia that presents a growing dilemma worldwide. Alzheimer's disease is neuropathologically characterized by cerebral atrophy accompanied by deposition of senile plaques and neurofibrillary tangles. The plaques are primarily composed of the amyloid beta peptide (AP), which is produced following processing of the amyloid precursor protein (APP) by the proteases beta- and gamma-secretase. A familial link can be found in approximately half of all Alzheimer's disease cases. In a few families the disease is caused by pathogenic mutations located on three different genes encoding presenilin (PS) 1, PS2 and APP. PS is an important component of the complex executing gamma-secretase processing of APP. A detailed characterization of the distribution of PS1 mRNA revealed that PS1 was found both in neurons and peripheral tissues such as testis, kidney, spleen, adrenal gland and thymus. This distribution indicated that the function of PS1 was likely also systemic, and not only found in processes involved with Alzheimer's disease. This idea has been confirmed more recently with the realization that the proteolytic activities of the gamma-secretase complex act on both Notch signaling pathways as well as APP processing. Neuronal cell-death in Alzheimer's disease has been suggested to involve both inflammatory and apoptotic reactions. One way of investigating apoptotic cell death in the hippocampus, a region gravely affected in AD, is by treating rats with the neurotoxic agent trimethyltin (TMT). Using this model, hippocampal neurons may be studied in order to investigate relationships in the neurodegenerative pathway. Following TMT-induced intoxication, a significant reduction of mRNA encoding the APP isoform consisting of 695 amino acids (APP695) was observed. In contrast mRNA encoding APP containing a Kuniz protease inhibitor domain (APP-KPI) as well as PS1 were unaltered despite neuronal loss. This might be explained by mRNA expression in invading astrocytes. One week after TMT-treatment, neuronal cells died by apoptosis. In addition, interleukin 1beta (IL-1beta), an inflammatory marker, could be detected indicating dual effects of TMT on cell-death involving both apoptosis and necrosis. A novel mutation (E693G - the Arctic mutation) was identified in a Swedish family with Alzheimer's disease. Plasma AP levels were reduced in Arctic mutation carriers. Levels of A beta were also reduced in media from Arctic transfected cells. This is contrast to the effects seen with other Alzheimer's disease mutations, which all increase AP production. Biochemical characterization of the Arctic peptide revealed that Arctic AP displayed altered kinetic properties leading to the formation of more stable protofibrils, an intermediary species in the fibrillization pathway. Further investigations revealed that Arctic APP was processed differently compared to wt APP. The (alpha secretase cleavage was reduced and the beta-secretase cleavage increased. The high beta-secretase processing indicates an increased AP production, contradictory to previous findings on AP levels in plasma and media. One possible explanation could be that A beta with the Arctic substitution rapidly forms protofibrils. The protofibrils may be retained within the cells causing intracellular accumulation of AP and as a consequence less AP will be secreted from the cells. An increased intracellular load of AP, would lead to neuronal cell stress eventually resulting in neurodegeneration. This was also seen in stably transfected SH-SY5Y cells. Arctic APP reduced the viability of the cells, which underwent apoptotic cell-death. In addition, cell death inducers further aggravated the apoptotic effects of the Arctic mutation. Protofibril formation is central in the pathogenic process leading to Alzheimer's disease in the Arctic family. Protofibrils have also been suggested to be involved in the pathogenic events leading to Alzheimer's disease in non-familial cases. The Arctic mutation could therefore be a good model for protofibrillar disease and a valuable tool for future drug design

Immune-induced expression of lipocalin-2 in brain endothelial cells: relationship to interleukin-6, cyclooxygenase-2 and the febrile response

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Immune-Induced Expression of Lipocalin-2 in Brain Endothelial Cells : Relationship with Interleukin-6, Cyclooxygenase-2 and the Febrile Response

Interleukin (IL)-6 is critical for the febrile response to peripheral immune challenge. However, the mechanism by which IL-6 enables fever is still unknown. To characterise the IL-6-dependent fever generating pathway, we used microarray analysis to identify differentially expressed genes in the brain of lipopolysaccharide (LPS)-treated IL-6 wild-type and knockout mice. Mice lacking IL-6 displayed a two-fold lower expression of the lipocalin-2 gene (lcn2), and this difference was confirmed by real-time reverse transcriptase-polymerase chain reaction. Conversely, the induction of lipocalin-2 protein was observed in brain vascular cells following i.p. administration of recombinant IL-6, suggesting a direct relationship between IL-6 and lipocalin-2. Immunohistochemical analysis also revealed that LPS-induced lipocalin-2 is expressed by brain endothelial cells and is partly co-localised with cyclooxygenase-2 (Cox-2), the rate-limiting enzyme for the production of inflammatory induced prostaglandin E2 (PGE2), which is the key mediator of fever. The direct role of lipocalin-2 in fever was examined in LPS-challenged lipocalin-2 knockout mice. In both male and female mice, normal fever responses were observed at near-thermoneutral conditions (2930 degrees C) but when recorded at normal room temperature (1920 degrees C), the body temperature of lipocalin-2 knockout female mice displayed an attenuated fever response compared to their wild-type littermates. This difference was reflected in significantly attenuated mRNA expression of Cox-2 in the brain of lipocalin-2 knockout female mice, but not of male mice, following challenge with peripheral LPS. Our findings suggest that IL-6 influences the expression of lipocalin-2, which in turn may be involved in the control of the formation of Cox-2, and hence central PGE2-production. We have thus identified lipocalin-2 as a new factor in the pathway of inflammatory IL-6 signalling. However, the effect of lipocalin-2 on fever is small, being sex-dependent and ambient temperature-specific, and thus lipocalin-2 cannot be considered as a major mediator of the IL-6-dependent fever generating pathway

Minor Changes in Gene Expression in the Mouse Preoptic Hypothalamic Region by Inflammation-Induced Prostaglandin E2

We investigated to what extent inflammation-induced prostaglandin E2 (PGE2) regulates gene expression in the central nervous system. Wild-type mice and mice with deletion of the gene encoding microsomal prostaglandin E synthase-1 (mPGES-1), which cannot produce inflammation-induced PGE2, were subjected to peripheral injection of bacterial wall lipopolysaccharide (LPS) and killed after 5 h. The median and medial preoptic nuclei, which are rich in prostaglandin E receptors, were isolated by laser capture microdissection (LCM), and subjected to whole genome microarray analysis. Although the immune stimulus induced robust transcriptional changes in the brain, as seen by a quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) on selected genes, only small PGE2-dependent gene expression changes were observed in the gene array analysis and, for only two genes, a pronounced differential expression between LPS-treated wild-type and mPGES-1 knockout mice could be verified by qRT-PCR. These were Hspa1a and Hspa1b, encoding heat shock proteins, which showed a two- to three-fold higher expression in wild-type mice than in knockout mice after immune challenge. However, the induced expression of these genes was found to be secondary to increased body temperature because they were induced also by cage exchange stress, which did not elicit PGE2 synthesis, and thus were not induced per se by PGE2-elicited transcriptional events. Our findings suggest that inflammation-induced PGE2 has little effect on gene expression in the preoptic region, and that centrally elicited disease symptoms, although PGE2-dependent, occur as a result of regulation of neuronal excitability that is a consequence of intracellular, transcriptional-independent signalling cascades. Our findings also imply that the profound changes in gene expression in the brain that are elicited by peripheral inflammation occur independently of PGE2 via a yet unidentified mechanism

Host knockout of E-prostanoid 2 receptors reduces tumor growth and causes major alterations of gene expression in prostaglandin E2-producing tumors

Prostaglandin E-2 (PGE(2)) is elevated in a variety of malignant tumors and has been shown to affect several hallmarks of cancer. Accordingly, the PGE, receptor, E-prostanoid 2 (EP2), has been reported to be associated with patient survival and reduced tumor growth in EP2-knockout mice. Thus, the aim of the present study was to screen for major gene expression alterations in tumor tissue growing in EP2-knockout mice. EP2-knockout mice were bred and implanted with EP2 receptor-expressing and PGE(2)-producing epithelial-like tumors. Tumor tissue and plasma were collected and used for analyses with gene expression microarrays and multiplex enzyme-linked immunosorbent assays. Tumor growth, acute phase reactions/systemic inflammation and the expression of interleukin-6 were reduced in EP2-knockout tumor-bearing mice. Several hundreds of genes displayed major changes of expression in the tumor tissue when grown in EP2-knockout mice. Such gene alterations involved several different cellular functions, including sternness, migration and cell signaling. Besides gene expression, several long non-coding RNAs were downregulated in the tumors from the EP2-knockout mice. Overall, PGE(2) signaling via host EP2 receptors affected a large number of different genes involved in tumor progression based on signaling between host stroma and tumor cells, which caused reduced tumor growth.Funding Agencies|Swedish Cancer Society [CAN 2010/255]; Swedish State under the LUA/ALF agreement; Assar Gabrielsson foundation; Magnus Bergvall foundation</p

Beneficial effects of increased lysozyme levels in Alzheimer\u27s disease modelled in Drosophila melanogaster

Genetic polymorphisms of immune genes that associate with higher risk to develop Alzheimer\u27s disease (AD) have led to an increased research interest on the involvement of the immune system in AD pathogenesis. A link between amyloid pathology and immune gene expression was suggested in a genome-wide gene expression study of transgenic amyloid mouse models. In this study, the gene expression of lysozyme, a major player in the innate immune system, was found to be increased in a comparable pattern as the amyloid pathology developed in transgenic mouse models of AD. A similar pattern was seen at protein levels of lysozyme in human AD brain and CSF, but this lysozyme pattern was not seen in a tau transgenic mouse model. Lysozyme was demonstrated to be beneficial for different Drosophila melanogaster models of AD. In flies that expressed Aβ1-42 or AβPP together with BACE1 in the eyes, the rough eye phenotype indicative of toxicity was completely rescued by coexpression of lysozyme. In Drosophila flies bearing the Aβ1-42 variant with the Arctic gene mutation, lysozyme increased the fly survival and decreased locomotor dysfunction dose dependently. An interaction between lysozyme and Aβ1-42 in the Drosophila eye was discovered. We propose that the increased levels of lysozyme, seen in mouse models of AD and in human AD cases, were triggered by Aβ1-42 and caused a beneficial effect by binding of lysozyme to toxic species of Aβ1-42, which prevented these from exerting their toxic effects. These results emphasize the possibility of lysozyme as biomarker and therapeutic target for AD