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Project description:Ocular marginal zone lymphoma is a common type of low-grade B-cell lymphoma. To investigate the genomic changes that occur in ocular marginal zone lymphoma, we analyzed 10 cases of ocular marginal zone lymphoma using whole-genome and RNA sequencing and an additional 38 cases using targeted sequencing. Major genetic alterations affecting genes involved in nuclear factor (NF)-κB pathway activation (60%), chromatin modification and transcriptional regulation (44%), and B-cell differentiation (23%) were identified. In whole-genome sequencing, the 6q23.3 region containing TNFAIP3 was deleted in 5 samples (50%). In addition, 5 structural variation breakpoints in the first intron of IL20RA located in the 6q23.3 region was found in 3 samples (30%). In targeted sequencing, a disruptive mutation of TNFAIP3 was the most common alteration (54%), followed by mutations of TBL1XR1 (18%), cAMP response element binding proteins (CREBBP) (17%) and KMT2D (6%). All TBL1XR1 mutations were located within the WD40 domain, and TBL1XR1 mutants transfected into 293T cells increased TBL1XR1 binding with nuclear receptor corepressor (NCoR), leading to increased degradation of NCoR and the activation of NF-κB and JUN target genes. This study confirms genes involving in the activation of the NF-kB signaling pathway is the major driver in the oncogenesis of ocular MZL.
| S-EPMC5370020 | biostudies-literature
Project description:Our spatiotemporal data confirmed activation of Tbl1xr1 in hepatocytes after 2/3 hepatectomy. TBL1XR1 is a transcriptional cofactor inducing ubiquitination and degradation of NCoR/SMRT co-repressors and NCoR is a negative regulator of hepatocyte proliferation acting through histone deacetylases (HDACs). We have examined the role of TBL1XR1 in liver regeneration through in vivo shRNA knockdown using adeno-associated viruses (shNC and shTbl1xr1) specifically targeting hepatocytes. The knockdown of Tbl1xr1 results in impair hepatocyte proliferation.To investigate the downstream targets of TBL1XR1 during liver regenration, we here perform the bulk RNA-seq for shNC and shTbl1xr1 at D2 after hepatectomy. Our data show demonstrated that Tbl1xr1 knockdown not only led to reduced cell cycle genes but also to impaired fatty acid β-oxidation as the most obviously affected liver function.
2024-02-05 | GSE254481 | GEO
Project description:TBL1XR1 gene is associated with multiple developmental disorders presenting several neurological aspects. The relative protein is involved in regulation of important cellular pathways and master regulators of transcriptional output including nuclear receptor repressors, Wnt signaling, and MECP2 protein. However, TBL1XR1 mutations (including complete loss of its functions) have not been experimentally studied in neurological context, leaving a lack of knowledge in the mechanisms at the basis of the diseases. We show that Tbl1xr1 knock-out mice exhibit behavioral and neuronal abnormalities. Either the absence of TBL1XR1, or point mutations interfering with stability/regulation of NCOR complex induced decreased proliferation and increased differentiation in neural progenitors. We suggest that this developmental unbalance is due to the failure in the regulation of MAPK cascade. Together, our results broaden the molecular and functional aftermath of TBL1XR1 deficiency associated with human disorders.
2021-03-16 | GSE162750 | GEO
Project description:Diffuse large B-cell lymphomas (DLBCL) encompass a heterogeneous group of diseases derived from different stages of B-cell differentiation. The most clinically aggressive forms of DLBCL, C5/MCD, carry activating mutations in canonical B-cell signaling pathways, as well as early-occurring hits in the poorly-characterized gene TBL1XR1. Here, we investigated the role of TBL1XR1 mutations in the early steps of malignant transformation. We found that TBL1XR1 mutations disrupt germinal center development, and introduce a cell fate bias towards memory B (MB) cells. At the molecular level, TBL1XR1 mutations trigger a switch, by which the SMRT/HDAC3 co-repressor complex shuttles between the lineage-defining transcription factors BCL6 and BACH2. We further demonstrate that terminal differentiation of TBL1XR1 mutant MB is limited upon recall, and that these MB re-enter the germinal center reaction instead, suggesting a role for these cells as the cell-of-origin of C5/MCD DLBCL.
2020-07-02 | GSE139059 | GEO
Project description:Extranodal marginal zone lymphoma is a type of low-grade B-cell lymphoma that can be classified as a mucosal-associated lymphoid tissue (MALT) lymphoma. Recently, second-generation or next-generation sequencing (NGS), which allows simultaneous sequencing of hundreds to billions of DNA strands, has been a focus of attention and is rapidly being adopted in various fields. In the present study, paraffin-embedded tissue samples of gastric MALT lymphoma (n=1) and small intestine MALT lymphoma (n=4) were selected, and DNA was extracted from the tissue samples. After performing quality control, NGS was performed using HemaSCAN™, a custom panel of 426 genes, including essential blood cancer genes. NGS revealed single nucleotide variations (SNVs), short insertions and deletions (InDels) and copy number variations (CNVs). These genomic variants were reported as annotated, known or novel variants. An annotated variant, an erb-b2 receptor tyrosine kinase 2 gene amplification, was observed in one patient. Known and novel variants, including SNVs of SET binding protein 6 (SETBP6), Runt-related transcription factor 1 and Kelch-like ECH-associated protein 1 genes, InDel of the marker of proliferation Ki-67 gene, and CNVs of the zinc finger protein 703 and NOTCH1 genes, were observed in ≥2 patients. Additionally, InDels with frameshift mutations were identified in the B-cell lymphoma/leukemia 10, DEAD-box helicase 3 X-linked, forkhead box O3 and mucin 2, oligomeric mucus/gel-forming genes in one patient. Since few NGS studies have been performed on MALT lymphoma, the current results were unable to determine if the different mutations that were identified are 'actionable' (that is, potentially responsive to a targeted therapy) Further studies are required to determine the associations between genetic mutations and the development of MALT lymphoma.
| S-EPMC7491050 | biostudies-literature
Project description:The etiology and pathogenesis of ocular adnexal extranodal marginal zone lymphoma (OAEMZL) are still unknown and the association with Chlamydophila psittaci (C. psittaci) has been shown in only some geographic regions. Herein, we comprehensively examined the frequency of chromosomal translocations as well as CARD11, MYD88 (L265P), and A20 mutations/deletions in 45 C. psittaci negative OAEMZLs. t(14;18)(q32;q21) IGH-MALT1 and t(11;18)(q21;q21) API2-MALT1 were not detected in any of the analyzed tumors while three tumors harbored IGH translocations to an unidentified partner. CARD11 mutations were not found in all analyzed tumors, while the MYD88 L265P mutation was detected in three (6.7%) tumors. A20 mutations and deletions were each detected in seven (15.6%) and six (13.3%) tumors, respectively. Therefore, the observed genetic aberrations could account for the activation of the nuclear factor (NF)-kB signaling pathway in only a minority of the cases. Further studies are needed to identify the molecular mechanisms underlying the pathogenesis of OAEMZL.
| S-EPMC3773926 | biostudies-literature
Project description:The pathogenesis of Chlamydophila (C.) psittaci negative ocular adnexal extranodal marginal zone lymphomas (OAEMZLs) is poorly understood. OAEMZLs are monoclonal tumors expressing a biased repertoire of mutated surface immunoglobulins. Antigenic activation of the B cell receptor (BCR) may play a role in the pathogenesis of these lymphomas. We have analyzed the reactivity of recombinant OAEMZL immunoglobulins. OAEMZL antibodies reacted with self-human antigens, as demonstrated by enzyme-linked immunosorbent assays, HEp-2 immunofluorescence and human protein microarrays. All the analyzed recombinant antibodies (rAbs) exhibited polyreactivity by comprehensive protein array antibody reactivity and some rAbs also demonstrated rheumatoid factor activity. The identity of several reactive antigens was confirmed by microcapillary reverse-phase HPLC nano-electrospray tandem mass spectrometry. The tested rAbs frequently reacted with shared intracellular and extracellular self-antigens (e.g. galectin-3). Furthermore, these self-antigens induced BCR signaling in B cells expressing cognate surface immunoglobulins derived from OAEMZLs. These findings suggest that interactions between self-antigens and cognate OAEMZL tumor-derived BCRs are functional, inducing intracellular signaling. Overall our findings suggest that self-antigen-induced BCR stimulation may be implicated in the pathogenesis of C. psittaci negative OAEMZLs. Antibody Specificity Profiling with four OAEMZL rAbs (Ab4438, Ab4726, Ab5334, and Ab11274) performed on ProtoArray Human Protein Microarrays
2015-01-30 | E-GEOD-65443 | biostudies-arrayexpress
Project description:The marginal zone (MZ) of the mouse spleen contains macrophages that express receptors that trap pathogens, including the scavenger receptor macrophage receptor with a collagenous structure and the C-type lectin specific intracellular adhesion molecule-grabbing nonintegrin receptor 1 (SIGN-R1). We previously reported that expression of SIGN-R1 was decreased in CD19-deficient mice. In this study, we demonstrate that SIGN-R1 is expressed on a subset of macrophage receptor with a collagenous structure (MARCO)(+) macrophages. This subset is diminished when MZ B cells are absent due to either genetic developmental defects or following transient migration of B cells out of the MZ. When B cells return to the MZ, there is a delay in recovery of SIGN-R1-expressing macrophages. During this period, capture of Ficoll, which for the macrophages requires SIGN-R1, remains defective not only by the macrophages, but also by the B cells. Thus, MZ B cells regulate expression of molecules on macrophages that are important for trapping Ag, which, in turn, is required for Ag capture by the B cells.
| S-EPMC3099422 | biostudies-literature
Project description:Ocular adnexal mucosa associated lymphoid tissue lymphomas (OAMALTL) are the most common lymphomas of the eye. The potential roles for specific antigens in these lymphomas are still controversial. Previously we examined IGHV usage and mutations in Chlamydophila (C) psittaci-negative OAMALTL, demonstrating biased use of the IGHV4 family and IGHV4-34 gene and evidence for antigen selection. Herein, we examined the IGKV/IGLV gene usage and mutations in 34 C. psittaci-negative OAMALTL originating from the orbit (15), conjunctivae (14), and lacrimal gland (5). Clonal potentially functional IGKV/IGLV gene sequences were identified in 30 tumors (18 kappa and 12 lambda). An overrepresentation of the IGKV4 family (P < 0.01) was observed. The IGKV3-20*01 allele was used at a greater frequency than in normal peripheral blood B-lymphocytes (P = 0.02) and commonly paired with the IGHV4-34 allele. Twenty-seven of the 30 unique light chain sequences displayed mutations from germline and evidence for antigen selection. Overall our findings demonstrate that in C. psittaci-negative OAMALTL there is a biased usage of IGKV families and genes, which harbor somatic mutations. These findings and the specific paring between the IGKV3-20*01 and IGHV4-34 alleles suggest that specific antigens could play an important role in the pathogenesis of these lymphomas.
| S-EPMC3644856 | biostudies-literature
Project description:Unique and shared cytogenetic abnormalities have been documented for marginal zone lymphomas (MZLs) arising at different sites. Recently, homozygous deletions of the chromosomal band 6q23, involving the tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20) gene, a negative regulator of NF-kappaB, were described in ocular adnexal MZL, suggesting a role for A20 as a tumor suppressor in this disease. Here, we investigated inactivation of A20 by DNA mutations or deletions in a panel of extranodal MZL (EMZL), nodal MZL (NMZL), and splenic MZL (SMZL). Inactivating mutations encoding truncated A20 proteins were identified in 6 (19%) of 32 MZLs, including 2 (18%) of 11 EMZLs, 3 (33%) of 9 NMZLs, and 1 (8%) of 12 SMZLs. Two additional unmutated nonsplenic MZLs also showed monoallelic or biallelic A20 deletions by fluorescent in situ hybridization (FISH) and/or SNP-arrays. Thus, A20 inactivation by either somatic mutation and/or deletion represents a common genetic aberration across all MZL subtypes, which may contribute to lymphomagenesis by inducing constitutive NF-kappaB activation.
| S-EPMC2686142 | biostudies-literature