SPI1/PU.1 controls fibroblast polarization and tissue fibrosis
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ABSTRACT:
PROVIDER: PRJNA504646 | ENA |
REPOSITORIES: ENA
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Project description:Fibroblasts are polymorphic cells with pleiotropic roles in organ morphogenesis, tissue homeostasis and immune responses. In fibrotic diseases, fibroblasts synthesize abundant amounts of extracellular matrix which lead to scaring and organ failure. In sharp contrast, the hallmark feature of fibroblasts in arthritis is matrix degradation by the release of metalloproteinases and degrading enzymes, and subsequent tissue destruction. The mechanisms driving these functionally opposing pro-fibrotic and pro-inflammatory phenotypes of fibroblasts are enigmatic. We have compared resting, fibrotic, and inflammatory fibroblasts; PU.1 was overexpressed in dermal fibroblasts and compared to scr-transfected controls. Fibrotic fibroblasts isolated from the skin of patients with systemic sclerosis were treated with PU.1 inhibitor and compared to untreated fibrotic fibroblasts and respective healthy controls. Through this, we identified the transcription factor PU.1 as an essential orchestrator of the pro-fibrotic gene expression program. The interplay between transcriptional and post-transcriptional mechanisms which normally control PU.1 expression is perturbed in fibrotic diseases such as pulmonary fibrosis, systemic sclerosis, liver cirrhosis, kidney fibrosis and chronic graft-versus-host disease, resulting in upregulation of PU.1, the induction of fibrosis-associated gene sets, and a phenotypic switch in matrix-producing pro-fibrotic fibroblasts. In contrast, inactivation of PU.1 disrupts the fibrotic network and enables re-programming of fibrotic fibroblasts into resting fibroblasts with regression of fibrosis in different organs. Targeting of PU.1 may thus represent a novel therapeutic approach for the treatment of a wide range of fibrotic diseases.
2018-11-09 | GSE122334 | GEO
Project description:The goal of the experiment was to understand the epigenetic effects of PU.1 haploinsufficiency on pro-B cells. The RS4:11 cell line was edited both mono and biallelicaly via electroporation of Cas9 and guides. Following editing, aliquots of unedited (SPI1 +/+), mono (SPI1 +/-) and biallellicaly edited (SPI1 -/-) cells were lysed before undergoing the transposition reaction. After transposition, the ATAC-seq libraries were purified and then amplified via PCR. Libraries were sequenced using the Illumina Novaseq platform.
2021-03-24 | E-MTAB-8676 | biostudies-arrayexpress
Project description:The ETS transcription factor SPI1/PU.1 controls fibroblast polarization and tissue fibrosis
| PRJNA480591 | ENA
Project description:Fibroblasts are polymorphic cells with pleiotropic roles in organ morphogenesis, tissue homeostasis and immune responses. In fibrotic diseases, fibroblasts synthesize abundant amounts of extracellular matrix, which induces scarring and organ failure. By contrast, a hallmark feature of fibroblasts in arthritis is degradation of the extracellular matrix because of the release of metalloproteinases and degrading enzymes, and subsequent tissue destruction. The mechanisms that drive these functionally opposing pro-fibrotic and pro-inflammatory phenotypes of fibroblasts remain unknown. Here we identify the transcription factor PU.1 as an essential regulator of the pro-fibrotic gene expression program. The interplay between transcriptional and post-transcriptional mechanisms that normally control the expression of PU.1 expression is perturbed in various fibrotic diseases, resulting in the upregulation of PU.1, induction of fibrosis-associated gene sets and a phenotypic switch in extracellular matrix-producing pro-fibrotic fibroblasts. By contrast, pharmacological and genetic inactivation of PU.1 disrupts the fibrotic network and enables reprogramming of fibrotic fibroblasts into resting fibroblasts, leading to regression of fibrosis in several organs.
| S-EPMC6526281 | biostudies-literature
Project description:SPI1 (PU.1) was recently reported as a genetic risk factor of Alzheimer’s disease (AD) in large-scale genome-wide association studies (GWAS). However, it is unknown whether PU.1 should be downregulated or increased to have therapeutic benefits. This is a critical question that must be answered before initiating any drug discovery project. To investigate the effect of modulating PU.1 level on AD pathology, we performed biochemical, histological, transcriptomic, and proteomic analyses using PU.1-knockdown and overexpression mouse models. PU.1-knockdown markedly increased amyloid-b (Ab) levels, amyloid plaque deposition, and gliosis. Conversely, PU.1-overexpression significantly decreased Ab levels, amyloid plaque deposition, gliosis, and dystrophic neurites. Furthermore, we identified several biological pathways, such as immune response pathways and complement system, regulated by the altered PU.1 expression through the analyses of proteomics as well as bulk and single-cell transcriptomics data. Our data provide crucial in vivo data to guide future therapeutic strategies for AD.
2024-03-18 | GSE225669 | GEO
Project description:SPI1 (PU.1) was recently reported as a genetic risk factor of Alzheimer’s disease (AD) in large-scale genome-wide association studies (GWAS). However, it is unknown whether PU.1 should be downregulated or increased to have therapeutic benefits. This is a critical question that must be answered before initiating any drug discovery project. To investigate the effect of modulating PU.1 level on AD pathology, we performed biochemical, histological, transcriptomic, and proteomic analyses using PU.1-knockdown and overexpression mouse models. PU.1-knockdown markedly increased amyloid-b (Ab) levels, amyloid plaque deposition, and gliosis. Conversely, PU.1-overexpression significantly decreased Ab levels, amyloid plaque deposition, gliosis, and dystrophic neurites. Furthermore, we identified several biological pathways, such as immune response pathways and complement system, regulated by the altered PU.1 expression through the analyses of proteomics as well as bulk and single-cell transcriptomics data. Our data provide crucial in vivo data to guide future therapeutic strategies for AD.
2024-03-18 | GSE222624 | GEO
Project description:Although originally described as transcriptional activator, SPI1/PU.1, a major player in haematopoiesis whose alterations are associated with haematological malignancies, has the ability to repress transcription. Here, we investigated the mechanisms underlying gene repression in the erythroid lineage, in which SPI1 exerts an oncogenic function by blocking differentiation. We show that SPI1 represses genes by binding active enhancers that are located in intergenic or gene body regions. HDAC1 acts as a cooperative mediator of SPI1-induced transcriptional repression by deacetylating SPI1-bound enhancers in a subset of genes, including those involved in erythroid differentiation. Enhancer deacetylation impacts on promoter acetylation, chromatin accessibility and RNA pol II occupancy. In addition to the activities of HDAC1, polycomb repressive complex 2 (PRC2) reinforces gene repression by depositing H3K27me3 at promoter sequences when SPI1 is located at enhancer sequences. Moreover, our study identified a synergistic relationship between PRC2 and HDAC1 complexes in mediating the transcriptional repression activity of SPI1, ultimately inducing synergistic adverse effects on leukaemic cell survival. Our results highlight the importance of the mechanism underlying transcriptional repression in leukemic cells, involving complex functional connections between SPI1 and the epigenetic regulators PRC2 and HDAC1.
2022-07-25 | GSE203658 | GEO
Project description:Although originally described as transcriptional activator, SPI1/PU.1, a major player in haematopoiesis whose alterations are associated with haematological malignancies, has the ability to repress transcription. Here, we investigated the mechanisms underlying gene repression in the erythroid lineage, in which SPI1 exerts an oncogenic function by blocking differentiation. We show that SPI1 represses genes by binding active enhancers that are located in intergenic or gene body regions. HDAC1 acts as a cooperative mediator of SPI1-induced transcriptional repression by deacetylating SPI1-bound enhancers in a subset of genes, including those involved in erythroid differentiation. Enhancer deacetylation impacts on promoter acetylation, chromatin accessibility and RNA pol II occupancy. In addition to the activities of HDAC1, polycomb repressive complex 2 (PRC2) reinforces gene repression by depositing H3K27me3 at promoter sequences when SPI1 is located at enhancer sequences. Moreover, our study identified a synergistic relationship between PRC2 and HDAC1 complexes in mediating the transcriptional repression activity of SPI1, ultimately inducing synergistic adverse effects on leukaemic cell survival. Our results highlight the importance of the mechanism underlying transcriptional repression in leukemic cells, involving complex functional connections between SPI1 and the epigenetic regulators PRC2 and HDAC1.
2022-07-25 | GSE172087 | GEO
Project description:Although originally described as transcriptional activator, SPI1/PU.1, a major player in haematopoiesis whose alterations are associated with haematological malignancies, has the ability to repress transcription. Here, we investigated the mechanisms underlying gene repression in the erythroid lineage, in which SPI1 exerts an oncogenic function by blocking differentiation. We show that SPI1 represses genes by binding active enhancers that are located in intergenic or gene body regions. HDAC1 acts as a cooperative mediator of SPI1-induced transcriptional repression by deacetylating SPI1-bound enhancers in a subset of genes, including those involved in erythroid differentiation. Enhancer deacetylation impacts on promoter acetylation, chromatin accessibility and RNA pol II occupancy. In addition to the activities of HDAC1, polycomb repressive complex 2 (PRC2) reinforces gene repression by depositing H3K27me3 at promoter sequences when SPI1 is located at enhancer sequences. Moreover, our study identified a synergistic relationship between PRC2 and HDAC1 complexes in mediating the transcriptional repression activity of SPI1, ultimately inducing synergistic adverse effects on leukaemic cell survival. Our results highlight the importance of the mechanism underlying transcriptional repression in leukemic cells, involving complex functional connections between SPI1 and the epigenetic regulators PRC2 and HDAC1.
2022-07-25 | GSE172086 | GEO
Project description:Although originally described as transcriptional activator, SPI1/PU.1, a major player in haematopoiesis whose alterations are associated with haematological malignancies, has the ability to repress transcription. Here, we investigated the mechanisms underlying gene repression in the erythroid lineage, in which SPI1 exerts an oncogenic function by blocking differentiation. We show that SPI1 represses genes by binding active enhancers that are located in intergenic or gene body regions. HDAC1 acts as a cooperative mediator of SPI1-induced transcriptional repression by deacetylating SPI1-bound enhancers in a subset of genes, including those involved in erythroid differentiation. Enhancer deacetylation impacts on promoter acetylation, chromatin accessibility and RNA pol II occupancy. In addition to the activities of HDAC1, polycomb repressive complex 2 (PRC2) reinforces gene repression by depositing H3K27me3 at promoter sequences when SPI1 is located at enhancer sequences. Moreover, our study identified a synergistic relationship between PRC2 and HDAC1 complexes in mediating the transcriptional repression activity of SPI1, ultimately inducing synergistic adverse effects on leukaemic cell survival. Our results highlight the importance of the mechanism underlying transcriptional repression in leukemic cells, involving complex functional connections between SPI1 and the epigenetic regulators PRC2 and HDAC1.
2022-07-25 | GSE172085 | GEO