Smc3 regulates B-cell transit through germinal centers and restricts their malignant transformation (HiC)
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE143853 | GEO | 2020/10/13
REPOSITORIES: GEO
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Project description:During the germinal center (GC) reaction, B-cells undergo extensive redistribution of cohesin complex and 3D re-organization of their genomes. Yet, the significance of cohesin and architectural programming in the humoral immune response is unknown. Herein we report that conditional homozygous deletion of cohesin subunit Smc3 abrogated GC formation, yet in marked contrast, Smc3 haploinsufficiency induced GC hyperplasia, skewing of GC polarity and impaired plasma cell differentiation. Transcriptional and architectural profiling revealed defects in GC terminal differentiation programs controlled by lymphoma epigenetic tumor suppressors Tet2 and Kmt2d, and failure of Smc3+/- GC B-cells to switch from B-cell to plasma cell lineage factors. There was also impaired connectivity of gene regulatory elements controlling tumor suppressor genes, and accordingly Smc3 haploinsufficiency accelerated lymphomagenesis in mice with constitutive Bcl6 expression. Collectively, our data indicate a dose dependent function for cohesin in humoral immunity to facilitate the B-cell to plasma cell lineage switch, while restricting their malignant transformation.
2020-10-13 | GSE146754 | GEO
Project description:During the germinal center (GC) reaction, B-cells undergo extensive redistribution of cohesin complex and 3D re-organization of their genomes. Yet, the significance of cohesin and architectural programming in the humoral immune response is unknown. Herein we report that conditional homozygous deletion of cohesin subunit Smc3 abrogated GC formation, yet in marked contrast, Smc3 haploinsufficiency induced GC hyperplasia, skewing of GC polarity and impaired plasma cell differentiation. Transcriptional and architectural profiling revealed defects in GC terminal differentiation programs controlled by lymphoma epigenetic tumor suppressors Tet2 and Kmt2d, and failure of Smc3+/- GC B-cells to switch from B-cell to plasma cell lineage factors. There was also impaired connectivity of gene regulatory elements controlling tumor suppressor genes, and accordingly Smc3 haploinsufficiency accelerated lymphomagenesis in mice with constitutive Bcl6 expression. Collectively, our data indicate a dose dependent function for cohesin in humoral immunity to facilitate the B-cell to plasma cell lineage switch, while restricting their malignant transformation.
2020-10-13 | GSE146753 | GEO
Project description:During the germinal center (GC) reaction, B-cells undergo extensive redistribution of cohesin complex and 3D re-organization of their genomes. Yet, the significance of cohesin and architectural programming in the humoral immune response is unknown. Herein we report that conditional homozygous deletion of cohesin subunit Smc3 abrogated GC formation, yet in marked contrast, Smc3 haploinsufficiency induced GC hyperplasia, skewing of GC polarity and impaired plasma cell differentiation. Transcriptional and architectural profiling revealed defects in GC terminal differentiation programs controlled by lymphoma epigenetic tumor suppressors Tet2 and Kmt2d, and failure of Smc3+/- GC B-cells to switch from B-cell to plasma cell lineage factors. There was also impaired connectivity of gene regulatory elements controlling tumor suppressor genes, and accordingly Smc3 haploinsufficiency accelerated lymphomagenesis in mice with constitutive Bcl6 expression. Collectively, our data indicate a dose dependent function for cohesin in humoral immunity to facilitate the B-cell to plasma cell lineage switch, while restricting their malignant transformation.
2020-10-13 | GSE146755 | GEO
Project description:The cohesin complex plays critical roles in genomic stability and gene expression through effects on 3D architecture. Cohesin core subunit genes are mutated across a wide cross-section of cancers, but not in germinal center (GC) derived lymphomas. In spite of this, haploinsufficiency of cohesin ATPase subunit Smc3 was shown to contribute to malignant transformation of GC B-cells in mice. Herein we explored potential mechanisms and clinical relevance of Smc3 deficiency in GC lymphomagenesis. Transcriptional profiling of Smc3 deficient murine lymphomas revealed downregulation of genes repressed by loss of epigenetic tumor suppressors Tet2 and Kmt2d. Profiling 3D chromosomal interactions in lymphomas revealed impaired enhancer-promoter interactions affecting genes like Tet2, which was aberrantly downregulated in Smc3 deficient lymphomas. Tet2 plays important roles in B-cell exit from the GC reaction, and single cell RNA-seq profiles and phenotypic trajectory analysis in Smc3 mutant mice revealed a specific defect in commitment to the final steps of plasma cell differentiation. Although Smc3 deficiency resulted in structural abnormalities in GC B-cells, there was no increase of somatic mutations or structural variants in Smc3 haploinsufficient lymphomas, suggesting that cohesin deficiency largely induces lymphomas through disruption of enhancer-promoter interactions of terminal differentiation and tumor suppressor genes. Strikingly, the presence of the Smc3 deficient GC B-cell transcriptional signature in human patients with GC-derived diffuse large B-cell lymphoma (DLBCL) was linked to inferior clinical outcome and low expression of cohesin core subunits. Reciprocally, reduced expression of cohesin subunits was an independent risk factor for worse survival int DLBCL patient cohorts. Collectively, the data suggest that Smc3 functions as a bona fide tumor suppressor for lymphomas through non-genetic mechanisms, and drives disease by disrupting the commitment of GC B-cells to the plasma cell fate.
2021-09-01 | GSE171598 | GEO
Project description:The cohesin complex plays critical roles in genomic stability and gene expression through effects on 3D architecture. Cohesin core subunit genes are mutated across a wide cross-section of cancers, but not in germinal center (GC) derived lymphomas. In spite of this, haploinsufficiency of cohesin ATPase subunit Smc3 was shown to contribute to malignant transformation of GC B-cells in mice. Herein we explored potential mechanisms and clinical relevance of Smc3 deficiency in GC lymphomagenesis. Transcriptional profiling of Smc3 deficient murine lymphomas revealed downregulation of genes repressed by loss of epigenetic tumor suppressors Tet2 and Kmt2d. Profiling 3D chromosomal interactions in lymphomas revealed impaired enhancer-promoter interactions affecting genes like Tet2, which was aberrantly downregulated in Smc3 deficient lymphomas. Tet2 plays important roles in B-cell exit from the GC reaction, and single cell RNA-seq profiles and phenotypic trajectory analysis in Smc3 mutant mice revealed a specific defect in commitment to the final steps of plasma cell differentiation. Although Smc3 deficiency resulted in structural abnormalities in GC B-cells, there was no increase of somatic mutations or structural variants in Smc3 haploinsufficient lymphomas, suggesting that cohesin deficiency largely induces lymphomas through disruption of enhancer-promoter interactions of terminal differentiation and tumor suppressor genes. Strikingly, the presence of the Smc3 deficient GC B-cell transcriptional signature in human patients with GC-derived diffuse large B-cell lymphoma (DLBCL) was linked to inferior clinical outcome and low expression of cohesin core subunits. Reciprocally, reduced expression of cohesin subunits was an independent risk factor for worse survival int DLBCL patient cohorts. Collectively, the data suggest that Smc3 functions as a bona fide tumor suppressor for lymphomas through non-genetic mechanisms, and drives disease by disrupting the commitment of GC B-cells to the plasma cell fate.
2021-09-01 | GSE172331 | GEO
Project description:The cohesin complex plays critical roles in genomic stability and gene expression through effects on 3D architecture. Cohesin core subunit genes are mutated across a wide cross-section of cancers, but not in germinal center (GC) derived lymphomas. In spite of this, haploinsufficiency of cohesin ATPase subunit Smc3 was shown to contribute to malignant transformation of GC B-cells in mice. Herein we explored potential mechanisms and clinical relevance of Smc3 deficiency in GC lymphomagenesis. Transcriptional profiling of Smc3 deficient murine lymphomas revealed downregulation of genes repressed by loss of epigenetic tumor suppressors Tet2 and Kmt2d. Profiling 3D chromosomal interactions in lymphomas revealed impaired enhancer-promoter interactions affecting genes like Tet2, which was aberrantly downregulated in Smc3 deficient lymphomas. Tet2 plays important roles in B-cell exit from the GC reaction, and single cell RNA-seq profiles and phenotypic trajectory analysis in Smc3 mutant mice revealed a specific defect in commitment to the final steps of plasma cell differentiation. Although Smc3 deficiency resulted in structural abnormalities in GC B-cells, there was no increase of somatic mutations or structural variants in Smc3 haploinsufficient lymphomas, suggesting that cohesin deficiency largely induces lymphomas through disruption of enhancer-promoter interactions of terminal differentiation and tumor suppressor genes. Strikingly, the presence of the Smc3 deficient GC B-cell transcriptional signature in human patients with GC-derived diffuse large B-cell lymphoma (DLBCL) was linked to inferior clinical outcome and low expression of cohesin core subunits. Reciprocally, reduced expression of cohesin subunits was an independent risk factor for worse survival int DLBCL patient cohorts. Collectively, the data suggest that Smc3 functions as a bona fide tumor suppressor for lymphomas through non-genetic mechanisms, and drives disease by disrupting the commitment of GC B-cells to the plasma cell fate.
2021-09-01 | GSE172330 | GEO
Project description:Cohesin complex members have recently been identified as putative tumor suppressors in hematologic and epithelial malignancies. The cohesin complex guides chromosome segregation, however cohesin-mutant leukemias do not show genomic instability. We hypothesized reduced cohesin function alters chromatin structure and disrupts cis-regulatory architecture of hematopoietic progenitors. We investigated the consequences of Smc3 deletion in normal and malignant hematopoiesis. Bi-allelic Smc3 loss induced bone marrow aplasia with premature sister chromatid separation, and revealed an absolute requirement for cohesin in hematopoietic stem cell function. In contrast, Smc3 haploinsufficiency increased self-renewal in vitro and in vivo including competitive transplantation. Smc3 haploinsufficiency reduced coordinated transcriptional output, including reduced expression of transcription factors and other genes associated with lineage commitment. Smc3 haploinsufficiency cooperated with Flt3-ITD to induce acute leukemia in vivo, with potentiated Stat5 signaling and altered nucleolar topology. These data establish a dose-dependency for cohesin in regulating chromatin structure and hematopoietic stem cell function. ATAC-seq in murine c-kit+ cells for the following genotypes: Smc3 fl/+, Smc3 del/+, Flt3-ITD, Smc3 fl/del Flt3-ITD
2015-09-21 | E-GEOD-73215 | biostudies-arrayexpress
Project description:Immunoglobulin class switch recombination (CSR) is initiated by the transcription-coupled recruitment of activation induced cytidine deaminase (AID) to switch regions and by the subsequent generation and resolution of dsDNA breaks (DSBs). During, CSR the IgH locus undergoes dynamic three-dimensional structural changes in which promoters, enhancers and switch regions are brought to close proximity. Nevertheless, little is known about the underlying mechanisms. Here we show that during CSR, AID associates with subunits of cohesin, a complex previously implicated in DNA repair and in the formation of DNA loops between enhancers and promoters. By ChIP-Seq experiments, we find that Cohesin is dynamically recruited to the IgH locus during CSR and that knockdown of Cohesin or its regulatory subunits results in impaired CSR and abnormal DSB resolution. Our results are consistent with a model in which Cohesin controls the formation of long-range DNA loops at the IgH locus and the resolution of DSBs generated during CSR. Smc1, Smc3 and CTCF were immunoprecipitated from resting or in vitro activated B cells.
2013-10-11 | E-GEOD-43594 | biostudies-arrayexpress
Project description:Cohesion between sister chromatids is mediated by the chromosomal cohesin complex. In budding yeast, cohesin is loaded onto chromosomes during the G1 phase of the cell cycle. During S-phase, the replication fork-associated acetyltransferase Eco1 acetylates the cohesin subunit Smc3 to promote establishment of sister chromatid cohesion. At the time of anaphase, Smc3 loses its acetylation again, but the Smc3 deacetylase and possible importance of Smc3 deacetylation are unknown. Here, we show that the class I histone deacetylase family member Hos1 is responsible for Smc3 deacetylation. Cohesin is protected from deacetylation while bound to chromosomes, but is deacetylated as soon as it dissociates from chromosomes following separase cleavage at anaphase onset. Non-acetylated Smc3 is required as a substrate for cohesion establishment in the following cell cycle. Our results complete the description of the Smc3 acetylation cycle and provide unexpected insight into the importance of de novo Smc3 acetylation for cohesion establishment.
2010-06-10 | GSE22257 | GEO
Project description:Cohesin complex members have recently been identified as putative tumor suppressors in hematologic and epithelial malignancies. The cohesin complex guides chromosome segregation, however cohesin-mutant leukemias do not show genomic instability. We hypothesized reduced cohesin function alters chromatin structure and disrupts cis-regulatory architecture of hematopoietic progenitors. We investigated the consequences of Smc3 deletion in normal and malignant hematopoiesis. Bi-allelic Smc3 loss induced bone marrow aplasia with premature sister chromatid separation, and revealed an absolute requirement for cohesin in hematopoietic stem cell function. In contrast, Smc3 haploinsufficiency increased self-renewal in vitro and in vivo including competitive transplantation. Smc3 haploinsufficiency reduced coordinated transcriptional output, including reduced expression of transcription factors and other genes associated with lineage commitment. Smc3 haploinsufficiency cooperated with Flt3-ITD to induce acute leukemia in vivo, with potentiated Stat5 signaling and altered nucleolar topology. These data establish a dose-dependency for cohesin in regulating chromatin structure and hematopoietic stem cell function.
2015-10-01 | GSE73216 | GEO