Similar Datasets
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: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.
2024-07-31 | GSE267944 | 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 [ATAC-seq]
| PRJNA1035100 | ENA
Project description:Arid1a-dependent canonical BAF complex suppresses inflammatory programs to drive efficient GC B cell responses [RNA-seq]
| PRJNA1035095 | ENA
Project description:Arid1a-dependent canonical BAF complex suppresses inflammatory programs to drive efficient GC B cell responses [CUT&TAG]
| PRJNA1113682 | ENA
Project description:SF3B1 is the most commonly mutated RNA splicing factor in cancer1-4, but the mechanisms by which SF3B1 mutations promote malignancy are poorly understood. Here we integrated pan-cancer splicing analyses with a positive-enrichment CRISPR screen to prioritize splicing alterations that promote tumorigenesis. We report that diverse SF3B1 mutations converge on repression of BRD9, which is a core component of the recently described non-canonical BAF chromatin-remodelling complex that also contains GLTSCR1 and GLTSCR1L5-7. Mutant SF3B1 recognizes an aberrant, deep intronic branchpoint within BRD9 and thereby induces the inclusion of a poison exon that is derived from an endogenous retroviral element and subsequent degradation of BRD9 mRNA. Depletion of BRD9 causes the loss of non-canonical BAF at CTCF-associated loci and promotes melanomagenesis. BRD9 is a potent tumour suppressor in uveal melanoma, such that correcting mis-splicing of BRD9 in SF3B1-mutant cells using antisense oligonucleotides or CRISPR-directed mutagenesis suppresses tumour growth. Our results implicate the disruption of non-canonical BAF in the diverse cancer types that carry SF3B1 mutations and suggest a mechanism-based therapeutic approach for treating these malignancies.
| S-EPMC6858563 | biostudies-literature
Project description:Connections between epigenetic reprogramming and transcription or splicing create novel mechanistic networks that can be targeted with tailored therapies. Multiple subunits of the chromatin remodeling BAF complex, including ARID1A, play a role in oncogenesis, either as tumor suppressors or oncogenes. Recent work demonstrated that EWS-FLI1, the oncogenic driver of Ewing sarcoma (ES), plays a role in chromatin regulation through interactions with the BAF complex. However, the specific BAF subunits that interact with EWS-FLI1 and the precise role of the BAF complex in ES oncogenesis remain unknown. In addition to regulating transcription, EWS-FLI1 also alters the splicing of many mRNA isoforms, but the role of splicing modulation in ES oncogenesis is not well understood. We have identified a direct connection between the EWS-FLI1 protein and ARID1A isoform protein variant ARID1A-L. We demonstrate here that ARID1A-L is critical for ES maintenance and supports oncogenic transformation. We further report a novel feed-forward cycle in which EWS-FLI1 leads to preferential splicing of ARID1A-L, promoting ES growth, and ARID1A-L reciprocally promotes EWS-FLI1 protein stability. Dissecting this interaction may lead to improved cancer-specific drug targeting.
| S-EPMC6765149 | biostudies-literature
Project description:Mammalian SWI/SNF chromatin remodelling complexes exist in three distinct, final-form assemblies: canonical BAF (cBAF), PBAF and a newly characterized non-canonical complex (ncBAF). However, their complex-specific targeting on chromatin, functions and roles in disease remain largely undefined. Here, we comprehensively mapped complex assemblies on chromatin and found that ncBAF complexes uniquely localize to CTCF sites and promoters. We identified ncBAF subunits as synthetic lethal targets specific to synovial sarcoma and malignant rhabdoid tumours, which both exhibit cBAF complex (SMARCB1 subunit) perturbation. Chemical and biological depletion of the ncBAF subunit, BRD9, rapidly attenuates synovial sarcoma and malignant rhabdoid tumour cell proliferation. Importantly, in cBAF-perturbed cancers, ncBAF complexes maintain gene expression at retained CTCF-promoter sites and function in a manner distinct from fusion oncoprotein-bound complexes. Together, these findings unmask the unique targeting and functional roles of ncBAF complexes and present new cancer-specific therapeutic targets.
| S-EPMC6698386 | biostudies-literature