Project description:We recently showed that the mammalian genome encodes more than a thousand large intergenic non-coding RNAs (lincRNAs) that are clearly conserved across mammals and thus functional. Gene expression patterns have implicated these lincRNAs in diverse biological processes including cell cycle regulation, immune surveillance, and embryonic stem cell pluripotency. However, the mechanism by which these lincRNAs function is unknown. Here, we expand the catalog of human lincRNAs to ~3300 by analyzing chromatin-state maps of various human cell types. Inspired by the observation that the well-characterized lincRNA HOTAIR bind the Polycomb Repressive Complex 2 (PRC2), we tested whether many lincRNAs are physically associated with PRC2. Remarkably, we observe that ~20% of lincRNAs expressed in various cell types are bound by PRC2, and that additional lincRNAs are bound by other chromatin-modifying complexes. Moreover, we show that siRNA-mediated depletion of certain lincRNAs associated with PRC2 leads to changes in gene expression and that the upregulated genes are enriched for those normally silenced by PRC2. We propose a model in which some lincRNAs guide chromatin–modifying complexes to specific genomic loci to regulate gene expression. siRNA-mediated lincRNA knockdown siRNAs targeting specific lincRNAs were transected into human fibroblasts. Non-targeting siRNAs were used as controls. Both of these experiment types were hybridized to Affymetrix gene expression arrays. PRC2 RIP-Chip The PRC2 complex was immunoprecipitated using antibodies targetting Suz12 and the associated RNA was hybridized to Nimblegen tiling arrays representing lincRNAs. In parallel an IgG IP was performed and hybridized to the same NG arrays. RIP was performed for PRC2 and hybridized using a Cy3 label. In parallel, RIP was performed using IGG and labelled with Cy5 PRC2 RIP-Chip (dye swap) The PRC2 complex was immunoprecipitated using antibodies targetting Suz12 and the associated RNA was hybridized to Nimblegen tiling arrays representing lincRNAs. In parallel an IgG IP was performed and hybridized to the same NG arrays. RIP was performed for PRC2 and hybridized using a Cy5 label. In parallel, RIP was performed using IGG and labelled with Cy3 PRC2 RIP-Chip (no proteins) The PRC2 complex was immunoprecipitated using antibodies targetting Suz12 and the associated RNA was hybridized to Nimblegen tiling arrays representing lincRNAs. In parallel an IgG IP was performed and hybridized to the same NG arrays. RIP was performed for PRC2 and hybridized using a Cy3 label. In parallel, RIP was performed using IGG and labelled with Cy5 COREST RIP-Chip The COREST complex was immunoprecipitated using antibodies targetting COREST and the associated RNA was hybridized to Nimblegen tiling arrays representing lincRNAs. In parallel an IgG IP was performed and hybridized to the same NG arrays. RIP was performed for COREST and hybridized using a Cy3 label. In parallel, RIP was performed using IGG and labelled with Cy5 H3K27me3 and H3K4me2 modified histones RIP-Chip The H3K27me3 and H3K4me2 modified histones were immunoprecipitated using antibodies targetting COREST and the associated RNA was hybridized to Nimbelgen tiling arrays representing lincRNAs. In parallel an IgG IP was performed and hybridized to the same NG arrays. RIP was performed for COREST and hybridized using a Cy3 label. In parallel, RIP was performed using IGG and labelled with Cy5 Human lincRNA expression Human lincRNAs were profiled in HeLa, Lung FB, and Foot FB. In addition, nuclear and cytoplasmic fractions were taken in HeLa cells Total RNA was extracted from HeLa, Foot, and Lung cells and hybridized to NG tiling array. In addition, the nucleus was fractionated and RNA was hybridized to an array.

Project description:Animal models have enhanced our understanding of the pathogenesis of autoimmune diseases. For these models, genetically identical, inbred mice have commonly been used. Different inbred mouse strains, however, show a high variability in disease manifestation. Identifying the factors that influence this disease variability could provide unrecognized insights into pathogenesis. We established a novel antibody transfer-induced model of epidermolysis bullosa acquisita (EBA), an autoimmune disease characterized by (muco)-cutaneous blistering caused by anti-type VII collagen (COL7) autoantibodies. Blistering after anti-COL7 IgG (directed against the von-Willebrand-factor A like domain 2) transfer showed clear variability among inbred mouse strains; i.e. severe cutaneous blistering and inflammation in C57Bl/6J, and absence of skin lesions in MRL/MpJ mice. The transfer of anti-COL7 IgG into irradiated, EBA-resistant MRL/MpJ mice, rescued by transplantation with bone marrow from EBA-susceptible B6.AK-H2k mice, induced blistering. To the contrary, irradiated EBA-susceptible B6.AK-H2k mice that were rescued using MRL/MpJ bone marrow were devoid of blistering. In vitro, immune complex activation of neutrophils from C57Bl/6J or MRL/MpJ mice showed an impaired ROS release from the latter, whereas no differences were observed after PMA activation. This finding was paralleled by divergent expression profiles of immune-complex activated neutrophils from either C57Bl/6J or MRL/MpJ mice. Collectively, we demonstrate that radiosensitive cells determine the varying extent of skin inflammation and blistering in the end-stage effector phase of EBA. We used microarray to differentiate between the molecular response for the immune complex stimulated neutrophils in MRL/MpJ and C57Bl/6J mice To unravel the molecular basis for the different response to immune complex (IC) stimulation between MRL/MpJ and C57Bl/6J mice, the cells were activated using IC, and differential expression using microarray was compared between resting or activated neutrophils from MRL/MpJ or C57Bl/6J mice.

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Mus musculus

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