PADI4-mediated citrullination of histone H3 stimulates HIV-1 transcription
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ABSTRACT:
PROVIDER: PRJNA1143570 | ENA |
REPOSITORIES: ENA
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Project description:HIV-1 infection establishes a reservoir of long-lived cells with integrated proviral DNA that can persist despite antiretroviral therapy (ART). The mechanisms governing the transcriptional regulation of the provirus are complex and incompletely understood. Here, we investigated the role of histone H3 citrullination, a post-translational modification catalyzed by protein-arginine deiminase type-4 (PADI4), in HIV-1 transcription and latency. We found that PADI4 inhibition by GSK484 reduced HIV-1 transcription after T cell activation in ex vivo cultures of CD4 T cells from viremic and ART treated people living with HIV-1 (PLWH). The effect was more pronounced in the viremic group. Using cell models of HIV-1 latency, we showed that PADI4-mediated citrullination of histone H3 occurred at the HIV-1 promoter upon T cell stimulation which facilitated proviral transcription. HIV-1 preferentially integrated into genomic regions marked by H3 citrullination and these integrated proviruses were less prone to latency compared to those in non-citrullinated chromatin. Inhibiting PADI4 led to compaction of the HIV-1 promoter chromatin and an increase of HP1a-covered heterochromatin, in a mechanism partly dependent on the HUSH complex. Our data reveal a novel mechanism of HIV-1 transcriptional regulation by PADI4 through H3 citrullination.
2024-08-05 | GSE273899 | GEO
Project description:Citrullination refers to the conversion of arginine into the non-essential amino acid citrulline. Despite its importance in physiology and disease, global identification of citrullinated proteins and modification sites has remained challenging. Here, we combined quantitative mass spectrometry-based proteomics with differentiation of a leukemia cell line into neutrophil-like cells to reveal a comprehensive atlas of citrullination sites. Collectively, we identified 14.056 citrullination sites within 4.008 proteins and quantified their regulation in response to PADI4-specific inhibitor GSK484. Hereby we uncovered general principles about the mechanistic and biological aspects of citrullination function, while providing site-specific and quantitative regulation of thousands of PADI4 substrates, including signature histone marks and numerous non-histone events on transcriptional regulators and chromatin-related signaling effectors. Collectively, we describe systems attributes of the human citrullinome, reveal the existence of thousands citrullinated autoantigens in neutrophil cells, and provide a resource framework for investigating PADI4-specific functions and substrates for years to come.
2024-01-16 | PXD038702 | Pride
Project description:Peptidylarginine deiminase IV (PADI4) catalyzes the conversion of positively charged arginine and methylarginine residues to neutrally charged citrulline residues on histone tails. This activity has been linked to the repression of gene transcription on a limited number of genes. To broaden our knowledge of the regulatory potential of PADI4, we utilized chromatin immunoprecipitation coupled with promoter tiling array (ChIP-chip) to more comprehensively investigate the range of PADI4 target genes across the genome in MCF-7 cells. Results showed that PADI4 is enriched in the gene promoter regions near the transcription start sites (TSSs) and, surprisingly, this pattern of binding is primarily associated with actively transcribed genes. Computational analysis found Elk-1, a member of the ETS oncogene family, to be highly enriched around PADI4 binding sites and coimmunoprecipitation analysis then confirmed that Elk-1 physically associates with PADI4. The expression of two well characterized Elk-1 target genes, c-fos and egr-1, was then found to be inhibited following treatment of MCF-7 cells with a PADI4 specific inhibitor. The inhibitor also significantly reduced levels of acetylation at H4 lysine 5 at these promoters suggesting that the activating function of PADI4 at these target genes is mediated, in part, by interplay between histone citrullination and HAT-mediated acetylation. These findings greatly expand our knowledge of the role of PADI4 in gene regulation by defining a new role for PADI4 catalyzed histone citrullination in mediating gene transactivation. Two PADI4 ChIP-chip biological replicates from MCF-7 human breast cancer cells are included.
2011-03-31 | E-GEOD-18755 | biostudies-arrayexpress
Project description:Peptidylarginine deiminase IV (PADI4) catalyzes the conversion of positively charged arginine and methylarginine residues to neutrally charged citrulline residues on histone tails. This activity has been linked to the repression of gene transcription on a limited number of genes. To broaden our knowledge of the regulatory potential of PADI4, we utilized chromatin immunoprecipitation coupled with promoter tiling array (ChIP-chip) to more comprehensively investigate the range of PADI4 target genes across the genome in MCF-7 cells. Results showed that PADI4 is enriched in the gene promoter regions near the transcription start sites (TSSs) and, surprisingly, this pattern of binding is primarily associated with actively transcribed genes. Computational analysis found Elk-1, a member of the ETS oncogene family, to be highly enriched around PADI4 binding sites and coimmunoprecipitation analysis then confirmed that Elk-1 physically associates with PADI4. The expression of two well characterized Elk-1 target genes, c-fos and egr-1, was then found to be inhibited following treatment of MCF-7 cells with a PADI4 specific inhibitor. The inhibitor also significantly reduced levels of acetylation at H4 lysine 5 at these promoters suggesting that the activating function of PADI4 at these target genes is mediated, in part, by interplay between histone citrullination and HAT-mediated acetylation. These findings greatly expand our knowledge of the role of PADI4 in gene regulation by defining a new role for PADI4 catalyzed histone citrullination in mediating gene transactivation.
2011-03-31 | GSE18755 | GEO
Project description:The enzymatic activity of PADI4 was investigated by overexpression and chemical inhibition to determine the effects of arginine citrullination on histone displacement, reprogramming efficiency and the maintenance of pluripotent stem cells.
2013-11-22 | E-MTAB-1975 | biostudies-arrayexpress
Project description:Peptidylarginine deiminases (PADIs) catalyze post-translational modification of many target proteins and have been suggested to play a role in carcinogenesis. Since citrullination of histones by PADI4 was recently implicated in regulating embryonic stem and hematopoietic progenitor cells, here we investigated a possible role for PADI4 in regulating breast cancer stem cells. We showed by genetic and pharmacologic approaches that PADI4 activity limits the number of cancer stem cells (CSCs) in vitro and in vivo in multiple breast cancer models. A gene signature reflecting tumor cell-autonomous PADI4 inhibition is associated with poor outcome in human breast cancer datasets, consistent with a tumor suppressive role for PADI4. Mechanistically, PADI4 inhibition resulted in a global redistribution of histone H3 with accumulation around transcriptional start sites. Interestingly, epigenetic effects of PADI4 on the bulk tumor cell population did not explain the CSC phenotype. However, in sorted tumor cell populations, PADI4 down-regulated expression of the master transcription factors of stemness, NANOG and POU5F1, specifically in the cancer stem cell compartment, by reducing the transcriptionally activating H3R17me2a histone mark at those loci. This effect was not seen in the non-stem cells. Our findings reveal a novel role for PADI4 as a tumor suppressor in regulating breast cancer stem cells, and provide insights into context-specific effects of PADI4 in epigenetic modulation.
2021-01-11 | GSE138407 | GEO
Project description:Peptidylarginine deiminases (PADIs) catalyze post-translational modification of many target proteins and have been suggested to play a role in carcinogenesis. Since citrullination of histones by PADI4 was recently implicated in regulating embryonic stem and hematopoietic progenitor cells, here we investigated a possible role for PADI4 in regulating breast cancer stem cells. We showed by genetic and pharmacologic approaches that PADI4 activity limits the number of cancer stem cells (CSCs) in vitro and in vivo in multiple breast cancer models. A gene signature reflecting tumor cell-autonomous PADI4 inhibition is associated with poor outcome in human breast cancer datasets, consistent with a tumor suppressive role for PADI4. Mechanistically, PADI4 inhibition resulted in a global redistribution of histone H3 with accumulation around transcriptional start sites. Interestingly, epigenetic effects of PADI4 on the bulk tumor cell population did not explain the CSC phenotype. However, in sorted tumor cell populations, PADI4 down-regulated expression of the master transcription factors of stemness, NANOG and POU5F1, specifically in the cancer stem cell compartment, by reducing the transcriptionally activating H3R17me2a histone mark at those loci. This effect was not seen in the non-stem cells. Our findings reveal a novel role for PADI4 as a tumor suppressor in regulating breast cancer stem cells, and provide insights into context-specific effects of PADI4 in epigenetic modulation.
2021-01-11 | GSE143442 | GEO
Project description:Peptidylarginine deiminases (PADIs) catalyze post-translational modification of many target proteins and have been suggested to play a role in carcinogenesis. Since citrullination of histones by PADI4 was recently implicated in regulating embryonic stem and hematopoietic progenitor cells, here we investigated a possible role for PADI4 in regulating breast cancer stem cells. We showed by genetic and pharmacologic approaches that PADI4 activity limits the number of cancer stem cells (CSCs) in vitro and in vivo in multiple breast cancer models. A gene signature reflecting tumor cell-autonomous PADI4 inhibition is associated with poor outcome in human breast cancer datasets, consistent with a tumor suppressive role for PADI4. Mechanistically, PADI4 inhibition resulted in a global redistribution of histone H3 with accumulation around transcriptional start sites. Interestingly, epigenetic effects of PADI4 on the bulk tumor cell population did not explain the CSC phenotype. However, in sorted tumor cell populations, PADI4 down-regulated expression of the master transcription factors of stemness, NANOG and POU5F1, specifically in the cancer stem cell compartment, by reducing the transcriptionally activating H3R17me2a histone mark at those loci. This effect was not seen in the non-stem cells. Our findings reveal a novel role for PADI4 as a tumor suppressor in regulating breast cancer stem cells, and provide insights into context-specific effects of PADI4 in epigenetic modulation.
2021-01-11 | GSE138505 | GEO
Project description:Peptidylarginine deiminases (PADIs) catalyze post-translational modification of many target proteins and have been suggested to play a role in carcinogenesis. Since citrullination of histones by PADI4 was recently implicated in regulating embryonic stem and hematopoietic progenitor cells, here we investigated a possible role for PADI4 in regulating breast cancer stem cells. We showed by genetic and pharmacologic approaches that PADI4 activity limits the number of cancer stem cells (CSCs) in vitro and in vivo in multiple breast cancer models. A gene signature reflecting tumor cell-autonomous PADI4 inhibition is associated with poor outcome in human breast cancer datasets, consistent with a tumor suppressive role for PADI4. Mechanistically, PADI4 inhibition resulted in a global redistribution of histone H3 with accumulation around transcriptional start sites. Interestingly, epigenetic effects of PADI4 on the bulk tumor cell population did not explain the CSC phenotype. However, in sorted tumor cell populations, PADI4 down-regulated expression of the master transcription factors of stemness, NANOG and POU5F1, specifically in the cancer stem cell compartment, by reducing the transcriptionally activating H3R17me2a histone mark at those loci. This effect was not seen in the non-stem cells. Our findings reveal a novel role for PADI4 as a tumor suppressor in regulating breast cancer stem cells, and provide insights into context-specific effects of PADI4 in epigenetic modulation.
2021-01-11 | GSE138415 | GEO
Project description:Multiple myeloma (MM), an incurable plasma cell malignancy, requires localisation within the bone marrow in order to survive and proliferate. Interactions between the malignant plasma cell and bone marrow mesenchymal stem cell (BMMSC) are thought to be a critical determinant of this requirement, and include both physical and chemical components. There is increasing evidence that the phenotype of the BMMSC is stably altered in patients with MM. More recently, it has been suggested that this phenotypic transformation is also observed in patients with the benign condition known as monoclonal gammopathy of undetermined significance (MGUS), which almost always precedes MM. In this study, we describe a mechanism by which the peptidyl arginine deiminase 2 (PADI2) enzyme plays an key role in the control of malignant plasma cell phenotype by BMMSCs. PADI enzymes deiminate (citrullinate) peptidyl arginine residues, changing the function or interactions made by the target protein. We identified PADI2 as one of the most highly upregulated transcripts in BMMSCs from both MGUS and MM patients, and that through citrullination of arginine residue 26 of histone H3, it induces the upregulation of interleukin-6 (IL-6) expression. This directly leads to the acquisition of resistance to the chemotherapeutic agent, bortezomib, by malignant plasma cells. We therefore describe a novel mechanism by which BMMSC dysfunction in patients with MGUS and MM directly leads to pro-malignancy signalling through the citrullination of histone H3R26. 30 samples, 10 from each of three categories (control, MGUS, MM)
2016-08-03 | E-GEOD-80608 | biostudies-arrayexpress