Arid1a-dependent canonical BAF complex suppresses inflammatory programs to drive efficient GC B cell responses [ATAC-seq]
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PROVIDER: PRJNA1035100 | ENA |
REPOSITORIES: ENA
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Project description:Differentiating B cells in germinal centers (GC) require tightly coordinated transcriptional and epigenetic transitions to generate efficient humoral immune responses. The mammalian BAF (Brg1/Brm-associated factor) complexes are major regulators of nucleosomal remodeling, crucial for cellular differentiation and development, and are commonly mutated in several cancers, including GC-derived B cell lymphomas. However, the specific roles of distinct BAF complexes in GC B cell biology and the generation of functional humoral immune responses are not well-understood. Here, we show that the Arid1a-dependent canonical BAF (cBAF) complex is indispensable for generatingon of fully mature GCs and high affinity humoral immune responses. While Arid1a-deficient B cells undergo activation to initiate GC responses, they fail to sustain the GC program, resulting incausing premature GC collapse. Mechanistically, Arid1a-dependent cBAF activity establishes permissive chromatin landscapes at several thousand genomic regions during B cell activation and isare concomitantly required to suppress inflammatory gene programs to maintain transcriptional fidelity in early GC B cells. Interestingly, the inflammatory signatures instigated by Arid1a- deficiency in early GC B cells recruits neutrophils and inflammatory monocytes, and eventually disrupts GC homeostasis. Remarkably, dampening of inflammatory cues with anti-inflammatory glucocorticoid receptor signaling rescues GC B cell differentiation of Arid1a-deficient B cells, thus highlighting a critical role of inflammation in impeding GC responses. In sum, our work identifies essential functions of Arid1a-dependent BAF activity in promoting efficient GC responses. These findings further support recent paradigms uncovering a deterministic role of unrestrained inflammation in obstructing GC responses, common in patients with severe bacterial and viral infections.
2024-07-31 | GSE267944 | GEO
Project description:Differentiating B cells in germinal centers (GC) require tightly coordinated transcriptional and epigenetic transitions to generate efficient humoral immune responses. The mammalian BAF (Brg1/Brm-associated factor) complexes are major regulators of nucleosomal remodeling, crucial for cellular differentiation and development, and are commonly mutated in several cancers, including GC-derived B cell lymphomas. However, the specific roles of distinct BAF complexes in GC B cell biology and the generation of functional humoral immune responses are not well-understood. Here, we show that the Arid1a-dependent canonical BAF (cBAF) complex is indispensable for generatingon of fully mature GCs and high affinity humoral immune responses. While Arid1a-deficient B cells undergo activation to initiate GC responses, they fail to sustain the GC program, resulting incausing premature GC collapse. Mechanistically, Arid1a-dependent cBAF activity establishes permissive chromatin landscapes at several thousand genomic regions during B cell activation and isare concomitantly required to suppress inflammatory gene programs to maintain transcriptional fidelity in early GC B cells. Interestingly, the inflammatory signatures instigated by Arid1a- deficiency in early GC B cells recruits neutrophils and inflammatory monocytes, and eventually disrupts GC homeostasis. Remarkably, dampening of inflammatory cues with anti-inflammatory glucocorticoid receptor signaling rescues GC B cell differentiation of Arid1a-deficient B cells, thus highlighting a critical role of inflammation in impeding GC responses. In sum, our work identifies essential functions of Arid1a-dependent BAF activity in promoting efficient GC responses. These findings further support recent paradigms uncovering a deterministic role of unrestrained inflammation in obstructing GC responses, common in patients with severe bacterial and viral infections.
2024-02-14 | GSE246911 | GEO
Project description:Differentiating B cells in germinal centers (GC) require tightly coordinated transcriptional and epigenetic transitions to generate efficient humoral immune responses. The mammalian BAF (Brg1/Brm-associated factor) complexes are major regulators of nucleosomal remodeling, crucial for cellular differentiation and development, and are commonly mutated in several cancers, including GC-derived B cell lymphomas. However, the specific roles of distinct BAF complexes in GC B cell biology and the generation of functional humoral immune responses are not well-understood. Here, we show that the Arid1a-dependent canonical BAF (cBAF) complex is indispensable for generatingon of fully mature GCs and high affinity humoral immune responses. While Arid1a-deficient B cells undergo activation to initiate GC responses, they fail to sustain the GC program, resulting incausing premature GC collapse. Mechanistically, Arid1a-dependent cBAF activity establishes permissive chromatin landscapes at several thousand genomic regions during B cell activation and isare concomitantly required to suppress inflammatory gene programs to maintain transcriptional fidelity in early GC B cells. Interestingly, the inflammatory signatures instigated by Arid1a- deficiency in early GC B cells recruits neutrophils and inflammatory monocytes, and eventually disrupts GC homeostasis. Remarkably, dampening of inflammatory cues with anti-inflammatory glucocorticoid receptor signaling rescues GC B cell differentiation of Arid1a-deficient B cells, thus highlighting a critical role of inflammation in impeding GC responses. In sum, our work identifies essential functions of Arid1a-dependent BAF activity in promoting efficient GC responses. These findings further support recent paradigms uncovering a deterministic role of unrestrained inflammation in obstructing GC responses, common in patients with severe bacterial and viral infections.
2024-02-14 | GSE246912 | GEO
Project description:Arid1a-dependent canonical BAF complex suppresses inflammatory programs to drive efficient GC B cell responses
| PRJNA1035089 | ENA
Project description:Arid1a-dependent canonical BAF complex suppresses inflammatory programs to drive efficient GC B cell responses [CUT&TAG]
| PRJNA1113682 | ENA
Project description:Arid1a-dependent canonical BAF complex suppresses inflammatory programs to drive efficient GC B cell responses [RNA-seq]
| PRJNA1035095 | ENA
Project description:The BAF complex modulates chromatin accessibility. Specific BAF configurations have functional consequences, and subunit switches are essential for cell differentiation. ARID1B and its paralog ARID1A encode for mutually exclusive BAF subunits. De novo ARID1B haploinsufficient mutations cause a neurodevelopmental disorder spectrum, including Coffin-Siris syndrome, which is characterized by neurological and craniofacial features. Here, we reprogrammed ARID1B+/- Coffin-Siris patient-derived skin fibroblasts into iPSCs, and modeled cranial neural crest cell (CNCC) formation. We discovered that ARID1B is active only during the first stage of this process, coinciding with neuroectoderm specification, where it is part of a lineage-specific BAF configuration (ARID1B-BAF), including SMARCA4, and nine additional subunits. ARID1B-BAF acts as a gate-keeper, ensuring exit from pluripotency and lineage commitment, by attenuating NANOG, SOX2 and the thousands of enhancers directly regulated by these two pluripotency factors at the iPSC stage. In iPSCs, these enhancers are maintained active by an ARID1A-containing BAF. At the onset of differentiation, cells transition from ARID1A-BAF to ARID1B-BAF, eliciting attenuation of the NANOG/SOX2 networks, and triggering pluripotency exit. Coffin-Siris patient cells fail to perform the ARID1A/ARID1B switch, and maintain ARID1A-BAF at pluripotency enhancers throughout all stages of CNCC formation. This leads to a persistent and aberrant SOX2 and NANOG activity, which impairs CNCC formation. In fact, despite showing the typical neural crest signature (TFAP2A+, SOX9+), the ARID1B-haploinsufficient CNCCs are also NANOG-positive, in stark contrast with the ARID1B-wt CNCCs, which are NANOG-negative. These findings suggest a connection between ARID1B mutations, neuroectoderm formation, and a pathogenic mechanism for Coffin-Siris syndrome.
2021-10-12 | PXD028557 | Pride
Project description:Global CRISPR screens provide an unparalleled, longer-term experimental approach for the identification of essential genes in drug resistance. We used an ~18,000 gene deletion screen to discover ARID1A and other BAF complex components as the most critical factors required for response to two classes of Estrogen Receptor (ER) antagonists, namely ER degraders and Selective Estrogen Receptor Modulators (SERMs). Unexpectedly, ARID1A was also the top candidate for response to the BET inhibitor JQ1, but in the opposite direction, where loss of ARID1A sensitised breast cancer cells to BET inhibition. We show that ARIDA binds chromatin at ER cis-regulatory elements and can physically associate with ER in model systems and primary tumour samples. ARID1A binding to ER enhancer elements, can occur in the absence of ER, suggesting that its repressive activity occurs in an enhancer-specific, but ER-independent manner. Specific targeting of ARID1A validated the CRISPR screen and shows that depletion of BAF activity, does not result in redundancy from P-BAF, the other ATP-dependent chromatin remodelling complex, but instead results in loss of HDAC1 binding, increased Histone 4 lysine acetylation and subsequent BRD4-driven growth. ARID1A and the BAF complex therefore function as a critical mechanism of antiestrogen activity and mutation or depletion in BAF activity drives a BRD4-mediated proliferative program that is refractory to ER targeted agents. Since ARID1A is mutated in a subset of treatment-resistant disease, these findings provide mechanistic insight and treatment strategies for patients, based on BAF complex fidelity status.
2019-10-30 | GSE134270 | GEO
Project description:Global CRISPR screens provide an unparalleled, longer-term experimental approach for the identification of essential genes in drug resistance. We used an ~18,000 gene deletion screen to discover ARID1A and other BAF complex components as the most critical factors required for response to two classes of Estrogen Receptor (ER) antagonists, namely ER degraders and Selective Estrogen Receptor Modulators (SERMs). Unexpectedly, ARID1A was also the top candidate for response to the BET inhibitor JQ1, but in the opposite direction, where loss of ARID1A sensitised breast cancer cells to BET inhibition. We show that ARIDA binds chromatin at ER cis-regulatory elements and can physically associate with ER in model systems and primary tumour samples. ARID1A binding to ER enhancer elements, can occur in the absence of ER, suggesting that its repressive activity occurs in an enhancer-specific, but ER-independent manner. Specific targeting of ARID1A validated the CRISPR screen and shows that depletion of BAF activity, does not result in redundancy from P-BAF, the other ATP-dependent chromatin remodelling complex, but instead results in loss of HDAC1 binding, increased Histone 4 lysine acetylation and subsequent BRD4-driven growth. ARID1A and the BAF complex therefore function as a critical mechanism of antiestrogen activity and mutation or depletion in BAF activity drives a BRD4-mediated proliferative program that is refractory to ER targeted agents. Since ARID1A is mutated in a subset of treatment-resistant disease, these findings provide mechanistic insight and treatment strategies for patients, based on BAF complex fidelity status.
2019-10-30 | GSE123285 | GEO
Project description:Global CRISPR screens provide an unparalleled, longer-term experimental approach for the identification of essential genes in drug resistance. We used an ~18,000 gene deletion screen to discover ARID1A and other BAF complex components as the most critical factors required for response to two classes of Estrogen Receptor (ER) antagonists, namely ER degraders and Selective Estrogen Receptor Modulators (SERMs). Unexpectedly, ARID1A was also the top candidate for response to the BET inhibitor JQ1, but in the opposite direction, where loss of ARID1A sensitised breast cancer cells to BET inhibition. We show that ARIDA binds chromatin at ER cis-regulatory elements and can physically associate with ER in model systems and primary tumour samples. ARID1A binding to ER enhancer elements, can occur in the absence of ER, suggesting that its repressive activity occurs in an enhancer-specific, but ER-independent manner. Specific targeting of ARID1A validated the CRISPR screen and shows that depletion of BAF activity, does not result in redundancy from P-BAF, the other ATP-dependent chromatin remodelling complex, but instead results in loss of HDAC1 binding, increased Histone 4 lysine acetylation and subsequent BRD4-driven growth. ARID1A and the BAF complex therefore function as a critical mechanism of antiestrogen activity and mutation or depletion in BAF activity drives a BRD4-mediated proliferative program that is refractory to ER targeted agents. Since ARID1A is mutated in a subset of treatment-resistant disease, these findings provide mechanistic insight and treatment strategies for patients, based on BAF complex fidelity status.
2019-10-30 | GSE123284 | GEO