The efficiency of central nervous system (CNS) remyelination declines with age. This is in part due to an age-associated decline in the phagocytic removal of myelin debris, which contains inhibitors of oligodendrocyte progenitor cell differentiation. In this study we show that expression of genes involved in the retinoid X receptor (RXR) pathway are decreased with aging in myelin-phagocytosing cells. Loss of RXR function in young macrophages mimics aging by delaying remyelination after experimentally-induced demyelination, while RXR agonists partially restore myelin debris phagocytosis in aged macrophages. The FDA-approved RXR agonist bexarotene, when used in concentrations achievable in human subjects, caused a reversion of the gene expression profile in aging human monocytes to a more youthful profile. These results reveal the RXR pathway as a positive regulator of myelin debris clearance and a key player in the age-related decline in remyelination that may be targeted by available or newly-developed therapeutics.
Retinoid X receptor activation reverses age-related deficiencies in myelin debris phagocytosis and remyelination.
Specimen part, Disease, Treatment
View SamplesIntroduction: The kidney is the major arbiter of extracellular phosphate homeostasis. The vast majority of glomerular filtrated phosphate is reabsorbed in the proximal tubule. Posttransplant phosphaturia is common and aggravated by sirolimus immunosuppression. The cause of sirolimus induced phosphaturia however remains elusive.
Sirolimus induced phosphaturia is not caused by inhibition of renal apical sodium phosphate cotransporters.
Sex, Specimen part
View SamplesFetal spleens were collected at days 82 and 97 of gestation following maternal infection with BVDV on day 75 of gestation.
Attenuated lymphocyte activation leads to the development of immunotolerance in bovine fetuses persistently infected with bovine viral diarrhea virus†.
Sex, Specimen part
View SamplesMigrating schistosomula are an important stage of the schistosome lifecycle and represent a key target for elimination of infection by natural and vaccine induced host immune responses. To gain a better understanding of how these parasites initiate a primary host immune response we have characterised the host lung response to migrating Schistosoma japonicum schistosomula using a combination of histochemistry, microarrays and quantitative cytokine analysis. Our data suggest that, during a S. japonicum infection, actively migrating schistosomula induce a Type-2 cytokine response in the lung that may support the subsequent development of a CD4+ T helper 2 (Th2) response against egg antigens. This hypothesis is supported by the fact that schistosomula and schistosome eggs are known to express important Th2-inducing antigens such as omega-1, peroxiredoxin, kappa-5 and IPSE/alpha1. The host lung response to migrating schistosomula was associated with increased numbers of macrophages and expression of markers for alternatively activated macrophages (AAM) in the lung. Activation of AAM in the lung and at the systemic level could lead to the modulation of the host immune response to favour parasite survival. Induction of these cells could also contribute to diminished inflammatory responses to, for example, allergy and asthma that are known to be associated with helminth infections. These data enhance our understanding of the mechanisms whereby schistosomes may evade the immune response and the mechanisms by which schistosome infection can help influence the host response following exposure to allergenic stimuli.
Migrating Schistosoma japonicum schistosomula induce an innate immune response and wound healing in the murine lung.
Sex, Age, Specimen part
View SamplesSulphur is an essential macronutrient for plant growth and development. Reaching a thorough understanding of the molecular basis for changes in plant metabolism depending on the sulphur-nutritional status at the systems level will advance our basic knowledge and help target future crop improvement. Although the transcriptional responses induced by sulphate starvation have been studied in the past, knowledge of the regulation of sulphur metabolism is still fragmentary. This work focuses on the discovery of candidates for regulatory genes such as transcription factors (TFs) using omics technologies. For this purpose a short term sulphate-starvation / re-supply approach was used. ATH1 microarray studies and metabolite determinations yielded 21 TFs which responded more than 2-fold at the transcriptional level to sulphate starvation. Categorization by response behaviors under sulphate-starvation / re-supply and other nutrient starvations such as nitrate and phosphate allowed determination of whether the TF genes are specific for or common between distinct mineral nutrient depletions. Extending this co-behavior analysis to the whole transcriptome data set enabled prediction of putative downstream genes. Additionally, combinations of transcriptome and metabolome data allowed identification of relationships between TFs and downstream responses, namely, expression changes in biosynthetic genes and subsequent metabolic responses. Effect chains on glucosinolate and polyamine biosynthesis are discussed in detail. The knowledge gained from this study provides a blueprint for an integrated analysis of transcriptomics and metabolomics and application for the identification of uncharacterized genes.
Transcriptome and metabolome analysis of plant sulfate starvation and resupply provides novel information on transcriptional regulation of metabolism associated with sulfur, nitrogen and phosphorus nutritional responses in Arabidopsis.
Specimen part
View SamplesGene regulation via transcription factors influences the metabolic, adaptive and pathogenic capabilities of the organism. We report the transcriptomes of the mutants of six major P. aeruginosa PA14 trancription factors - RhlR, LasR, Anr, GacA, FleQ and CbrB. Overall design: The P. aeruginosa PA14 transposon mutants were analyzed by RNA-seq. All samples were cultivated in LB medium until reaching an OD600 of 2.0. For each biological replicate, three cultures were pooled for RNA extraction, library preparation and sequencing.
Functional modules of sigma factor regulons guarantee adaptability and evolvability.
Subject
View SamplesMany Gram-negative bacteria employ cell-to-cell communication mediated by N-acyl homoserine lactones (quorum sensing) to control expression of a wide range of genes including, but not limited to, genes encoding virulence factors. Outside the laboratory, the bacteria live in complex communities where signals may be perceived across species. We here present a newly found natural quorum sensing inhibitor, produced by the pseudomonads Pseudomonas sp. B13 and Pseudomonas reinekei MT1 as a blind end in the biodegradation of organochloride xenobiotics, which inhibits quorum sensing in P.aeruginosa in naturally occurring concentrations. This catabolite, 4-methylenebut-2-en-4-olide, also known as protoanemonin, has been reported to possess antibacterial properties, but seems to have dual functions. Using transcriptomics and proteomics, we found that protoanemonin significantly reduced expression of genes and secretion of proteins known to be under control of quorum sensing in P.aeruginosa. Moreover, we found activation of genes and gene products involved in iron starvation response. It is thus likely that inhibition of quorum sensing, as the production of antibiotics, is a phenomenon found in complex bacterial communities.
Protoanemonin: a natural quorum sensing inhibitor that selectively activates iron starvation response.
Compound
View SamplesThe response to the presence of the ncpBVDV-infected PI or TI fetus is expected to provide information on the impact of the PI fetus on the immune response of the dam
Persistent fetal infection with bovine viral diarrhea virus differentially affects maternal blood cell signal transduction pathways.
No sample metadata fields
View SamplesImmortalized, amelanotic melanocytes isolted from skin of Balb/c express enzymatically-inactive tyrosinase due to a homozygous point mutation (TGT->TCT) in tyrosinase gene, resulting in a lack of melanin . To serve as a control cell line, pigmentation was restored in these cells by correcting the point mutation using an RNA-DNA oligonucleotide (kingly gift from Dr. Alexeev Y. Vitali).
Melanocyte-secreted fibromodulin promotes an angiogenic microenvironment.
Specimen part
View SamplesRadiotherapy is widely used to treat human cancer. Patients locally recurring after radiotherapy, however, have increased risk of metastatic progression and poor prognosis. The clinical management of post-radiation recurrences remains an unresolved issue. Tumors growing in pre-irradiated tissues have an increased fraction of hypoxic cells and are more metastatic, a condition known as tumor bed effect. Here we demonstrate that tumor cells growing in a pre-irradiated bed, or selected in vitro though repeated cycles of severe hypoxia, retain an invasive and metastatic capacities when returned to normoxia. HIF activity, while it facilitates metastatic spreading of tumors growing in a pre-irradiated bed, is not essential. Through gene expression profiling and gain and loss of function experiments, we identified the matricellular protein CYR61 and aVb5 integrin, as proteins cooperating to mediate these effects. Inhibition of aVb5 integrin suppressed invasion and metastasis induced by CYR61 and attenuated metastasis of tumors growing within a pre-irradiated field. These results represent a conceptual advance to the understanding of the tumor bed effect and identify CYR61 and aVb5 integrin as proteins that co-operate to mediate metastasis. They also indicate aV integrin inhibition a potential therapeutic approach for preventing metastasis in patients at risk for post-radiation recurrences, which can be promptly tested in the clinic.
CYR61 and alphaVbeta5 integrin cooperate to promote invasion and metastasis of tumors growing in preirradiated stroma.
No sample metadata fields
View Samples