Although small RNAs efficiently control transposition activity of most transposons in the host genome, such immune system is not always applicable against new transposon's invasions. Here we explored a possibility to introduce potentially mobile copy of the Penelope retroelement previously implicated in hybrid dysgenesis syndrome in Drosophila virilis into the genomes of two distant Drosophila species. The consequences of such introduction were monitored at different phases after experimental colonization as well as in D. virilis species which is apparently in the process of ongoing Penelope invasion. We investigated the expression of Penelope and biogenesis of Penelope-derived small RNAs in D. virilis and D. melanogaster strains originally lacking active copies of this element after experimental Penelope invasion. These strains were transformed by constructs containing intact Penelope copies. We show that immediately after transformation, which imitates the first stage of retroelement invasion, Penelope undergoes transposition predominantly in somatic tissues, and may produce siRNAs that are apparently unable to completely silence its activity. However, at the later stages of colonization Penelope copies may jump into one of the piRNA-clusters, which results in production of homologous piRNAs that are maternally deposited and can silence euchromatic transcriptionally active copies of Penelope in trans and, hence, prevent further amplification of the invader in the host genome. Intact Penelope copies and different classes of Penelope-derived small RNAs were found in most geographical strains of D. virilis collected throughout the world. Importantly, all strains of this species containing full-length Penelope tested do not produce gonadal sterility in dysgenic crosses and, hence, exhibit neutral cytotype. In order to understand whether RNA interference mechanism able to target Penelope operates in related species of the virilis group we correlated the presence of full-length and potentially active Penelope with the occurrence of piRNAs homologous to this TE in the ovaries of species comprising the group. It was demonstrated, that Penelope-derived piRNAs are present in all virilis group species containing full-length but transcriptionally silent copies of this element that probably represent the remnants of its previous invasions taking place in the course of the virilis species divergent evolution. Overall design: piRNA size profile (23-29nt) was examined in D. melanogaster strains, where Penelope-piRNAs are detected by Northern blot
Evolution and dynamics of small RNA response to a retroelement invasion in Drosophila.
Specimen part, Cell line, Subject
View SamplesLangerhans cells (LCs) populate the mucosal epithelium, a major entry portal for pathogens, yet their ontogeny remains unclear. In contrast to skin LCs originating from self-renewing radioresistant embryonic precursors, we found that oral mucosal LCs derive from circulating radiosensitive precursors. Mucosal LCs can be segregated into CD103+CD11blow (CD103+LCs) and CD11b+CD103- (CD11b+LCs) subsets. We further demonstrated that similar to non-lymphoid dendritic cells (DCs), CD103+LCs originate from pre-DCs, whereas CD11b+LCs differentiate from both pre-DCs and monocytic precursors. Despite this ontogenetic discrepancy between skin and mucosal LCs, transcriptomic signature and immunological function of oral LCs highly resemble those of skin LCs but not DCs. These findings, along with their epithelial position, morphology and expression of LC-associated phenotype strongly suggest that oral mucosal LCs are genuine LCs. Collectively, in a tissue-dependent manner, murine LCs differentiate from at least three distinct precursors (embryonic, pre-DCs and monocytic) in steady state Overall design: The following cells were isolated from mice (2-4 replicates): Lung DCs, mucosal CD103+ LC, mucosal CD11b+ LC, Skin LC. Transcriptome analysis was performed.
Distinct Murine Mucosal Langerhans Cell Subsets Develop from Pre-dendritic Cells and Monocytes.
No sample metadata fields
View SamplesTargeted interference of sin3a-tgif1 function by SID decoy treatment inhibits WNT signaling and invasion in triple negative breast cancer cells. MDA-MB-231 cells were treated with scrambled SID control, 2.5M SID peptide or untreated for 24h.
Targeted interference of SIN3A-TGIF1 function by SID decoy treatment inhibits Wnt signaling and invasion in triple negative breast cancer cells.
Specimen part
View SamplesHistone deacetylase 9 (HDAC9) is expressed in B cells, and its overexpression has been observed in B-lymphoproliferative disorders, including B-cell non-Hodgkin lymphoma (B-NHL). We examined HDAC9 protein expression and copy number alterations in primary B-NHL samples, identifying high HDAC9 expression among various lymphoma entities and HDAC9 copy number gains in 50% of diffuse large B-cell lymphoma (DLBCL). To study the role of HDAC9 in lymphomagenesis, we generated a genetically engineered mouse (GEM) model that constitutively expressed an HDAC9 transgene throughout B-cell development under the control of the immunoglobulin heavy chain (IgH) enhancer (E). Here, we report that the E-HDAC9 GEM model develops splenic marginal zone lymphoma and lymphoproliferative disease (LPD) with progression towards aggressive DLBCL, with gene expression profiling supporting a germinal center cell origin, as is also seen in human B-NHL tumors. Analysis of E-HDAC9 tumors suggested that HDAC9 might contribute to lymphomagenesis by altering pathways involved in growth and survival, as well as modulating BCL6 activity and p53 tumor suppressor function. Epigenetic modifications play an important role in the germinal center response, and deregulation of the B-cell epigenome as a consequence of mutations and other genomic aberrations are being increasingly recognized as important steps in the pathogenesis of a variety of B-cell lymphomas. A thorough mechanistic understanding of these alterations will inform the use of targeted therapies for these malignancies. These findings strongly suggest a role for HDAC9 in B-NHL and establish a novel GEM model for the study of lymphomagenesis and, potentially, preclinical testing of therapeutic approaches based on histone deacetylase inhibitors.
Deregulated expression of HDAC9 in B cells promotes development of lymphoproliferative disease and lymphoma in mice.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Deregulated expression of HDAC9 in B cells promotes development of lymphoproliferative disease and lymphoma in mice.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Targeting the SIN3A-PF1 interaction inhibits epithelial to mesenchymal transition and maintenance of a stem cell phenotype in triple negative breast cancer.
Cell line
View SamplesTriple negative breast cancer (TNBC) is characterized by a poorly differentiated phenotype and limited treatment options. Aberrant epigenetics in this subtype represent a potential therapeutic opportunity, but a better understanding of the mechanisms contributing to the TNBC pathogenesis is required. The SIN3 molecular scaffold performs a critical role in multiple cellular processes, including epigenetic regulation, and has been identified as a potential therapeutic target. Using a competitive peptide corresponding to the SIN3 interaction domain of MAD (Tat-SID), we investigated the functional consequences of selectively blocking the paired amphipathic helix (PAH2) domain of SIN3. Here, we report the identification of the SID-containing adaptor PF1 as a factor required for maintenance of the TNBC stem cell phenotype and epithelial to mesenchymal transition (EMT). Tat-SID peptide blocked the interaction between SIN3A and PF1, leading to epigenetic modulation and transcriptional downregulation of TNBC stem cell and EMT markers. Importantly, Tat-SID treatment led to a reduction in primary tumor growth and disseminated metastatic disease in vivo. In support of these findings, knockdown of PF1 expression phenocopied treatment with Tat-SID both in vitro and in vivo. These results demonstrate a critical role for a complex containing SIN3A and PF1 in TNBC and provide a rational for its therapeutic targeting.
Targeting the SIN3A-PF1 interaction inhibits epithelial to mesenchymal transition and maintenance of a stem cell phenotype in triple negative breast cancer.
Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Inhibition of the LSD1 (KDM1A) demethylase reactivates the all-trans-retinoic acid differentiation pathway in acute myeloid leukemia.
Cell line, Treatment
View SamplesAll-trans-retinoic acid (ATRA) has been successfully used in therapy of acute promyelocytic leukemia (APL), a cytogenetically distinct subtype of acute myeloid leukemia (AML) but the response of non-APL AML cases to ATRA-based treatment has been poor. Here we show that, via epigenetic reprogramming, inhibitors of LSD1/KDM1 demethylase including tranylcypromine (TCP) unlocked the ATRA-driven therapeutic response in non-APL AML. LSD1 inhibition did not lead to an increase in genome-wide H3 lysine4 dimethylation (H3K4me2) but did increase H3K4me2 and expression of myeloid differentiation-associated genes. Importantly, treatment with ATRA plus TCP dramatically diminished engraftment of primary human AML cells in vivo in NOD.SCID mice, suggesting that ATRA in combination with TCP may target leukemia-initiating cells. Furthermore, initiation of ATRA plus TCP co-treatment 15 days post-engraftment of human AML cells in NOD.SCID gamma mice also revealed the ATRA plus TCP drug combination to have a potent anti-leukemic effect, which was superior to treatment with either drug alone. These data identify LSD1 as a therapeutic target and strongly suggest that it may contribute to AML pathogenesis by inhibiting the normal pro-differentiative function of ATRA, paving the way for novel combinatorial therapies of AML.
Inhibition of the LSD1 (KDM1A) demethylase reactivates the all-trans-retinoic acid differentiation pathway in acute myeloid leukemia.
Cell line, Treatment
View SamplesBecause most human stroke victims are elderly, studies of experimental stroke in the aged rather than the young rat model may be optimal for identifying clinically relevant cellular responses, as well for pinpointing beneficial interventions.
Transcriptomics of post-stroke angiogenesis in the aged brain.
Sex, Age, Specimen part
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