The apoA-I induced transcriptome and dependence on MyD88
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE13772 | GEO | 2010/06/15
SECONDARY ACCESSION(S): PRJNA110779
REPOSITORIES: GEO
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Project description:Specific mutations in Apolipoprotein A-I (ApoA-I) of high-density lipoprotein (HDL) are responsible for a late-onset systemic amyloidosis. Carriers do not exhibit increased cardiovascular disease risk despite reduced levels of ApoA-I/ HDL-cholesterol. To explain this paradox, we show that the HDL particle profile of L75P and L174S patients presents a higher relative abundance of the 8.4 nm vs 9.6 nm particles, and that serum from patients, as well as reconstituted 8.4 and 9.6 nm HDL particles (rHDL), possess increased capacity to catalyze cholesterol efflux from macrophages. Synchrotron radiation circular dichroism and hydrogen-deuterium exchange revealed that the variants in 8.4 nm rHDL have altered secondary structure composition and display a more flexible binding to lipids compared to their native counterpart. The reduced HDL-cholesterol levels of patients carrying ApoA-I amyloidogenic variants are thus balanced by higher proportion of small, dense HDL particles and better cholesterol efflux due to altered, region-specific protein structure dynamics.
2020-11-20 | PXD021266 | Pride
Project description:Lipopolysaccharide (LPS), a Toll-like receptor (TLR) 4 ligand, activates intracellular signaling via adaptors, MyD88 and TRIF, leading to the expression of various genes including proinflammatory cytokines. We used microarrays to examine influence of MyD88 or TRIF deficiency in LPS-inducible gene expression. Experiment Overall Design: Peritoneal macrophages from wild-type, MyD88-/- and TRIF-/- mice were stimulated with LPS for 0, 1 and 4 hours, followed by RNA extraction. Then hybridization on affymetrix microarrays was performed.
2009-03-01 | E-GEOD-14890 | biostudies-arrayexpress
Project description:Lipopolysaccharide (LPS), a Toll-like receptor (TLR) 4 ligand, activates intracellular signaling via adaptors, MyD88 and TRIF, leading to the expression of various genes including proinflammatory cytokines. We used microarrays to examine influence of MyD88 or TRIF deficiency in LPS-inducible gene expression. Keywords: Time course after LPS (100 ng/ml) stimulation
2009-02-19 | GSE14890 | GEO
Project description:To test the functional role of ApoA-I on microglia in the context of stress, we treated primary microglia with LPS stress with or without ApoA-I protein, and used bulk RNA-seq to evaluate if ApoA-I exhibits an anti-inflammatory role.
2024-10-15 | GSE264110 | GEO
Project description:HDL particles are known to possess several anti-atherogenic properties that include the removal of excess cholesterol from peripheral tissues, the maintenance of endothelial integrity, antioxidant and antiinflammatory activities. ApoA-I overexpression in apoE-deficient (EKO) mice has been shown to increase HDL levels and to strongly reduce atherosclerosis development. The aim of the study was to investigate gene expression patterns associated with atherosclerosis development in the aorta of EKO mice and how HDL plasma levels relate to gene expression patterns at different stages of atherosclerosis development and with different dietary treatments. Methods Eight weeks old EKO mice, EKO mice overexpressing human apoA-I (EKO/hA-I) and wild-type mice as controls were fed either Chow or Western diet for 6 or 22 weeks. Cholesterol distribution among lipoproteins was evaluated and atherosclerosis of the aorta was quantified. High-throughput sequencing technologies were used to analyse the transcriptome of the aorta of the three genotypes in each experimental condition. Results: In addition to the well-known activation of inflammation and immune response, the impairment of sphingolipid metabolism, phagosome-lysosome system and osteoclast differentiation emerged as relevant players in atherosclerosis development. The reduced atherosclerotic burden in the aorta of EKO mice expressing high levels of apoA-I was accompanied by a reduced activation of the immune system markers, as well as reduced perturbation of lysosomal activity and a better regulation of the sphingolipid synthesis pathway Conclusions. ApoA-I modulates atherosclerosis development in the aorta of EKO mice affecting the expression of pathways additional to those associated with inflammation and immune response
2020-12-22 | GSE163657 | GEO
Project description:We found ApoA-I from blood can be taken up by microglia in the brain. To determine if ApoA-I from circulation is sufficient to restore microglial transcriptomic state to a more wild-type-like state, we performed a rescue experiment by intravenously injecting ApoA-I protein into adult Apoa1 KO mice and sorted microglia with or without ApoA-I uptake for bulk transcriptomic analysis.
2024-10-15 | GSE264111 | GEO
Project description:Transcriptome analysis of submandibular glands in female MyD88+/+ and MyD88−/− NOD mice. Sjögren's syndrome (SS) is an autoimmune disease characterized by dysfunction of salivary glands (SGs) and lacrimal glands, which is caused by chronic inflammation associated with autoantibody and autoreactive lymphocyte infiltration. The pathogenic mechanism of SS has not been fully elucidated. Infiltrated lymphocytes form regularized structures similar to lymphoid follicles of secondary lymphoid organs, such as T/B cell compartments, high endothelial venules (HEVs), lymphatic vessels, and germinal centers, therefore being believed as an ectopic lymphoid tissue called tertiary lymphoid organs (TLO). We previously found that deletion of the Toll-like receptor/IL-1 receptor (TLR/IL-1R) adaptor molecule gene Myd88 in SS model mice NOD reduced the frequency of lymphocyte infiltration and HEV formation in SGs. In this study, we analyzed the effect of MyD88 deficiency on lymphoid follicle formation in SGs of NOD mice. Microarray analysis showed decreased expression of genes related to TLO, such as Cxcl13 and Cxcr5, in Myd88-deficient SGs. These results indicate that deficiency of TLR/IL-1R signaling decrease gene expression ot chemokines in SGs, suggesting MyD88-dependent signaling is directly involved in formation of lymphoid follicles in SS.
2021-09-01 | GSE157669 | GEO
Project description:The ABC subtype of diffuse large B cell lymphoma (DLBCL) remains the least curable form of this lymphoma despite recent advances in therapy. We have combined structural and functional genomics to triangulate on new oncogenic mechanisms and devise new therapeutic strategies. RNA interference screen revealed a dependence of ABC DLBCL cell lines on MYD88 and IRAK1. High throughput resequencing of RNA (RNA-Seq) revealed frequent somatic mutations in MYD88 that preferentially occurred in the ABC DLBCL subtype. Remarkably, one third of ABC DLBCL tumor samples harbored the same amino acid substitution, L265P, in the MYD88 TIR domain at an evolutionarily invariant residue in its hydrophobic core. This mutation was rare or absent in two other DLBCL subtypes, but was observed in 9% of MALT lymphomas. At a lower frequency, multiple other mutations were observed in the MYD88 TIR domain, occurring in both the ABC and GCB subtypes of DLBCL. Survival of ABC DLBCL lines bearing the L265P mutation was sustained by the mutant but not wild type MYD88 isoform, demonstrating that this MYD88 mutant is oncogenic and gain-of-function. The MYD88 L265P mutant assembled a protein complex that spontaneous triggers the phosphorylation of IRAK1, leading to NF-kB signaling, secretion of the cytokines IL-6, IL-10 and interferon-b, and JAK kinase signaling. These findings demonstrate that the MYD88 signaling pathway is integral to the pathogenesis of ABC DLBCL, providing a genetic rationale for therapeutic targeting of the MYD88 signaling pathway in this lymphoma subtype. To generate a gene expression signature of MYD88 signaling in ABC DLBCL, the HBL-1 cell line was transduced with retroviral vectors expressing either shMYD88-4 or shMYD88-7. Following puromycin selection, shRNA expression was induced for 24 or 48 hours and gene expression was measured, comparing uninduced (Cy3) to induced (Cy5) cells, using genome-wide Agilent 4x44K oligonucleotide microarrays. A signature of NF-kB signaling in ABC DLBCL was generated by treating HBL-1 cells with the IkB kinase beta inhibitor MLN120B for 2h, 3h, 4h, 6h, 8h, 12h, 16h, and 24h (Cy5), and comparing their gene expression to untreated cells (Cy3). A signature of JAK signaling in ABC DLBCL was generated by treating HBL-1 cells with JAK inhibitor I (5 micromolar; Calbiochem) for 2h, 4h, 6h, and 8h (Cy5) and comparing their gene expression to vehicle-treated cells (DMSO, Cy3). RNA-Seq data not provided.
2010-12-30 | E-GEOD-22900 | biostudies-arrayexpress
Project description:The ABC subtype of diffuse large B cell lymphoma (DLBCL) remains the least curable form of this lymphoma despite recent advances in therapy. We have combined structural and functional genomics to triangulate on new oncogenic mechanisms and devise new therapeutic strategies. RNA interference screen revealed a dependence of ABC DLBCL cell lines on MYD88 and IRAK1. High throughput resequencing of RNA (RNA-Seq) revealed frequent somatic mutations in MYD88 that preferentially occurred in the ABC DLBCL subtype. Remarkably, one third of ABC DLBCL tumor samples harbored the same amino acid substitution, L265P, in the MYD88 TIR domain at an evolutionarily invariant residue in its hydrophobic core. This mutation was rare or absent in two other DLBCL subtypes, but was observed in 9% of MALT lymphomas. At a lower frequency, multiple other mutations were observed in the MYD88 TIR domain, occurring in both the ABC and GCB subtypes of DLBCL. Survival of ABC DLBCL lines bearing the L265P mutation was sustained by the mutant but not wild type MYD88 isoform, demonstrating that this MYD88 mutant is oncogenic and gain-of-function. The MYD88 L265P mutant assembled a protein complex that spontaneous triggers the phosphorylation of IRAK1, leading to NF-kB signaling, secretion of the cytokines IL-6, IL-10 and interferon-b, and JAK kinase signaling. These findings demonstrate that the MYD88 signaling pathway is integral to the pathogenesis of ABC DLBCL, providing a genetic rationale for therapeutic targeting of the MYD88 signaling pathway in this lymphoma subtype.
2010-12-30 | GSE22900 | GEO
Project description:In the activated B-cell-like (ABC) subtype of diffuse large B cell lymphoma (DLBCL), the most frequent gain-of-function mutations target MyD88, a signaling adapter for Tolllike receptors (TLRs). The most prevalent oncogenic mutant, MyD88 L265P, occurs in 29% of cases and is the most active in engaging the NF-kappaB pathway. Here we show that MyD88 mutants do not function autonomously, but rather require TLR7, TLR9, and to a lesser extent, TLR4 to promote the survival of ABC DLBCL cells. Unlike wild type MyD88, MyD88 mutants associate constitutively with TLR7 and TLR9 in ABC DLBCL cells. Like ligand-induced TLR7/9 signaling in normal immune cells, the survival of ABC DLBCL cell lines depends upon translocation of TLR7 and TLR9 to acidic endolysosomes, where proteolytic processing of their ligand binding ectodomains is required for their oncogenic signaling. ABC DLBCL viability also depends upon CD14, a co-receptor for TLR7 and TLR9 that promotes engagement of nucleic acid ligands by these receptors. Point mutations in the TLR7 or TLR9 ectodomains that abrogate ligand binding and/or signaling were incapable of sustaining ABC DLBCL survival. An inhibitory oligonucleotide that suppresses TLR9 responses in normal B cells blocked NF-kappaB signaling and survival of ABC DLBCL lines. Together, these data suggest that an endogenous TLR ligand may play a pathogenic role in ABC DLBCL and provide a rationale for targeting TLR signaling to improve therapy of this aggressive lymphoma. Gene expression was analyzed using Agilent human 2-color 4X44K oligo gene expression arrays. Cell line, TMD8 ABC-DLBCL, was infected with control (shControl, Cy3), shLTR7 (Cy5) or shLTR9 (Cy5) and changes in gene expression were monitored on day 1 and day 2 after induction of the shRNA with doxycycline, co-hybridizing control and experimental samples (Cy3+Cy5), for a total of 4 arrays.
2014-05-21 | E-GEOD-47147 | biostudies-arrayexpress