RESUMEN
The development of multicellular organisms depends on spatiotemporally controlled differentiation of numerous cell types and their maintenance. To generate such diversity based on the invariant genetic information stored in DNA, epigenetic mechanisms, which are heritable changes in gene function that do not involve alterations to the underlying DNA sequence, are required to establish and maintain unique gene expression programs. Polycomb repressive complexes represent a paradigm of epigenetic regulation of developmentally regulated genes, and the roles of these complexes as well as the epigenetic marks they deposit, namely H3K27me3 and H2AK119ub, have been extensively studied. However, an emerging theme from recent studies is that not only the autonomous functions of the Polycomb repressive system, but also crosstalks of Polycomb with other epigenetic modifications, are important for gene regulation. In this review, we summarize how these crosstalk mechanisms have improved our understanding of Polycomb biology and how such knowledge could help with the design of cancer treatments that target the dysregulated epigenome.
Asunto(s)
Represión Epigenética , Genes del Desarrollo , Proteínas del Grupo Polycomb , Diferenciación Celular , Proteínas de Drosophila , Epigénesis Genética , Proteínas del Grupo Polycomb/genética , Proteínas del Grupo Polycomb/metabolismo , Humanos , AnimalesRESUMEN
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) evades the innate immune machinery through multiple viral proteins, including nonstructural protein 1 (NSP1). While NSP1 is known to suppress translation of host mRNAs, the mechanisms underlying its immune evasion properties remain elusive. By integrating RNA-seq, ribosome footprinting, and ChIP-seq in A549 cells we found that NSP1 predominantly represses transcription of immune-related genes by favoring Histone 3 Lysine 9 dimethylation (H3K9me2). G9a/GLP H3K9 methyltransferase inhibitor UNC0638 restored expression of antiviral genes and restricted SARS-CoV-2 replication. Our multi-omics study unravels an epigenetic mechanism underlying host immune evasion by SARS-CoV-2 NSP1. Elucidating the factors involved in this phenomenon, may have implications for understanding and treating viral infections and other immunomodulatory diseases.
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COVID-19 , SARS-CoV-2 , Humanos , COVID-19/genética , COVID-19/inmunología , COVID-19/virología , Represión Epigenética , SARS-CoV-2/genética , SARS-CoV-2/inmunología , SARS-CoV-2/metabolismo , Proteínas no Estructurales Virales/metabolismoRESUMEN
During in vitro culture, human pluripotent stem cells (hPSCs) often acquire survival advantages characterized by decreased susceptibility to mitochondrial cell death, known as "culture adaptation." This adaptation is associated with genetic and epigenetic abnormalities, including TP53 mutations, copy number variations, trisomy, and methylation changes. Understanding the molecular mechanisms underlying this acquired survival advantage is crucial for safe hPSC-based cell therapies. Through transcriptome and methylome analysis, we discovered that the epigenetic repression of CHCHD2, a mitochondrial protein, is a common occurrence during in vitro culture using enzymatic dissociation. We confirmed this finding through genetic perturbation and reconstitution experiments in normal human embryonic stem cells (hESCs). Loss of CHCHD2 expression conferred resistance to single cell dissociation-induced cell death, a common stress encountered during in vitro culture. Importantly, we found that the downregulation of CHCHD2 significantly attenuates the activity of Rho-associated protein kinase (ROCK), which is responsible for inducing single cell death in hESCs. This suggests that hESCs may survive routine enzyme-based cell dissociation by downregulating CHCHD2 and thereby attenuating ROCK activity. These findings provide insights into the mechanisms by which hPSCs acquire survival advantages and adapt to in vitro culture conditions.
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Células Madre Embrionarias Humanas , Células Madre Pluripotentes , Humanos , Línea Celular , Represión Epigenética , Variaciones en el Número de Copia de ADN , Células Madre Embrionarias Humanas/metabolismo , Diferenciación Celular , Supervivencia Celular , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Factores de Transcripción/genética , Factores de Transcripción/metabolismoRESUMEN
Although hyperhomocysteinemia (hHcys) has been recognized as an important independent risk factor in the progression of end-stage renal disease and the development of cardiovascular complications related to end-stage renal disease, the mechanisms triggering pathogenic actions of hHcys are not fully understood. The present study was mainly designed to investigate the role of HDACs in renal injury induced by hHcys. Firstly, we identified the expression patterns of HDACs and found that, among zinc-dependent HDACs, HDAC9 was preferentially upregulated in the kidney from mice with hHcys. Deficiency or pharmacological inhibition of HDAC9 ameliorated renal injury in mice with hHcys. Moreover, podocyte-specific deletion of HDAC9 significantly attenuated podocyte injury and proteinuria. In vitro, gene silencing of HDAC9 attenuated podocyte injury by inhibiting apoptosis, reducing oxidative stress and maintaining the expressions of podocyte slit diaphragm proteins. Mechanically, we proved for the first time that HDAC9 reduced the acetylation level of H3K9 in the promoter of Klotho, then inhibited gene transcription of Klotho, finally aggravating podocyte injury in hHcys. In conclusion, our results indicated that targeting of HDAC9 might be an attractive therapeutic strategy for the treatment of renal injury induced by hHcys.
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Hiperhomocisteinemia , Fallo Renal Crónico , Podocitos , Animales , Ratones , Represión Epigenética , Histona Desacetilasas/genética , Histona Desacetilasas/metabolismo , Hiperhomocisteinemia/genética , Hiperhomocisteinemia/complicaciones , Hiperhomocisteinemia/metabolismo , Fallo Renal Crónico/complicaciones , Fallo Renal Crónico/genética , Fallo Renal Crónico/metabolismo , Podocitos/patologíaRESUMEN
AIMS/HYPOTHESIS: Diabetes is associated with epigenetic modifications including DNA methylation and miRNA changes. Diabetic complications in the cornea can cause persistent epithelial defects and impaired wound healing due to limbal epithelial stem cell (LESC) dysfunction. In this study, we aimed to uncover epigenetic alterations in diabetic vs non-diabetic human limbal epithelial cells (LEC) enriched in LESC and identify new diabetic markers that can be targeted for therapy to normalise corneal epithelial wound healing and stem cell expression. METHODS: Human LEC were isolated, or organ-cultured corneas were obtained, from autopsy eyes from non-diabetic (59.87±20.89 years) and diabetic (71.93±9.29 years) donors. The groups were not statistically different in age. DNA was extracted from LEC for methylation analysis using Illumina Infinium 850K MethylationEPIC BeadChip and protein was extracted for Wnt phospho array analysis. Wound healing was studied using a scratch assay in LEC or 1-heptanol wounds in organ-cultured corneas. Organ-cultured corneas and LEC were transfected with WNT5A siRNA, miR-203a mimic or miR-203a inhibitor or were treated with recombinant Wnt-5a (200 ng/ml), DNA methylation inhibitor zebularine (1-20 µmol/l) or biodegradable nanobioconjugates (NBCs) based on polymalic acid scaffold containing antisense oligonucleotide (AON) to miR-203a or a control scrambled AON (15-20 µmol/l). RESULTS: There was significant differential DNA methylation between diabetic and non-diabetic LEC. WNT5A promoter was hypermethylated in diabetic LEC accompanied with markedly decreased Wnt-5a protein. Treatment of diabetic LEC and organ-cultured corneas with exogenous Wnt-5a accelerated wound healing by 1.4-fold (p<0.05) and 37% (p<0.05), respectively, and increased LESC and diabetic marker expression. Wnt-5a treatment in diabetic LEC increased the phosphorylation of members of the Ca2+-dependent non-canonical pathway (phospholipase Cγ1 and protein kinase Cß; by 1.15-fold [p<0.05] and 1.36-fold [p<0.05], respectively). In diabetic LEC, zebularine treatment increased the levels of Wnt-5a by 1.37-fold (p<0.01)and stimulated wound healing in a dose-dependent manner with a 1.6-fold (p<0.01) increase by 24 h. Moreover, zebularine also improved wound healing by 30% (p<0.01) in diabetic organ-cultured corneas and increased LESC and diabetic marker expression. Transfection of these cells with WNT5A siRNA abrogated wound healing stimulation by zebularine, suggesting that its effect was primarily due to inhibition of WNT5A hypermethylation. Treatment of diabetic LEC and organ-cultured corneas with NBC enhanced wound healing by 1.4-fold (p<0.01) and 23.3% (p<0.05), respectively, with increased expression of LESC and diabetic markers. CONCLUSIONS/INTERPRETATION: We provide the first account of epigenetic changes in diabetic corneas including dual inhibition of WNT5A by DNA methylation and miRNA action. Overall, Wnt-5a is a new corneal epithelial wound healing stimulator that can be targeted to improve wound healing and stem cells in the diabetic cornea. DATA AVAILABILITY: The DNA methylation dataset is available from the public GEO repository under accession no. GSE229328 ( https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE229328 ).
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Diabetes Mellitus , MicroARNs , Humanos , Represión Epigenética , Proteína Wnt-5a/genética , Proteína Wnt-5a/metabolismo , Diabetes Mellitus/genética , Diabetes Mellitus/metabolismo , MicroARNs/genética , MicroARNs/metabolismo , Células Madre/metabolismo , ARN Interferente Pequeño/metabolismo , Cicatrización de Heridas/genética , Células Epiteliales/metabolismoRESUMEN
Loss or downregulation of major histocompatibility complex class I (MHC-I) contributes to tumor immune evasion. We previously demonstrated that angiopoietin-like protein 2 (ANGPTL2) promotes tumor progression using a Xp11.2 translocation renal cell carcinoma (tRCC) mouse model. However, molecular mechanisms underlying ANGPTL2 tumor-promoting activity in the tRCC model remained unclear. Here, we report that ANGPTL2 deficiency in renal tubular epithelial cells slows tumor progression in the tRCC mouse model and promotes activated CD8+ T-cell infiltration of kidney tissues. We also found that Angptl2-deficient tumor cells show enhanced interferon γ-induced expression of MHC-I and increased susceptibility to CD8+ T-cell-mediated anti-tumor immune responses. Moreover, we provide evidence that the ANGPTL2-α5ß1 integrin pathway accelerates polycomb repressive complex 2-mediated repression of MHC-I expression in tumor cells. These findings suggest that ANGPTL2 signaling in tumor cells contributes to tumor immune evasion and that suppressing that signaling in tumor cells could serve as a potential strategy to facilitate tumor elimination by T-cell-mediated anti-tumor immunity.
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Carcinoma de Células Renales , Neoplasias Renales , Animales , Ratones , Proteína 2 Similar a la Angiopoyetina , Proteínas Similares a la Angiopoyetina/genética , Proteínas Similares a la Angiopoyetina/metabolismo , Escape del Tumor/genética , Represión Epigenética , Antígenos de Histocompatibilidad Clase I/genética , Carcinoma de Células Renales/genética , Modelos Animales de EnfermedadRESUMEN
The chromatin of animal cells contains two types of histones: canonical histones that are expressed during S phase of the cell cycle to package the newly replicated genome, and variant histones with specialized functions that are expressed throughout the cell cycle and in non-proliferating cells. Determining whether and how canonical and variant histones cooperate to regulate genome function is integral to understanding how chromatin-based processes affect normal and pathological development. Here, we demonstrate that variant histone H3.3 is essential for Drosophila development only when canonical histone gene copy number is reduced, suggesting that coordination between canonical H3.2 and variant H3.3 expression is necessary to provide sufficient H3 protein for normal genome function. To identify genes that depend upon, or are involved in, this coordinate regulation we screened for heterozygous chromosome 3 deficiencies that impair development of flies bearing reduced H3.2 and H3.3 gene copy number. We identified two regions of chromosome 3 that conferred this phenotype, one of which contains the Polycomb gene, which is necessary for establishing domains of facultative chromatin that repress master regulator genes during development. We further found that reduction in Polycomb dosage decreases viability of animals with no H3.3 gene copies. Moreover, heterozygous Polycomb mutations result in de-repression of the Polycomb target gene Ubx and cause ectopic sex combs when either canonical or variant H3 gene copy number is reduced. We conclude that Polycomb-mediated facultative heterochromatin function is compromised when canonical and variant H3 gene copy number falls below a critical threshold.
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Drosophila melanogaster , Dosificación de Gen , Histonas , Proteínas del Grupo Polycomb , Drosophila melanogaster/genética , Drosophila melanogaster/crecimiento & desarrollo , Drosophila melanogaster/metabolismo , Represión Epigenética , Regulación de la Expresión Génica , Histonas/genética , Histonas/metabolismo , Larva/genética , Larva/metabolismo , Proteínas del Grupo Polycomb/metabolismo , ARN Mensajero/metabolismo , AnimalesRESUMEN
SERRATE (SE) is a core protein for microRNA (miRNA) biogenesis as well as for mRNA alternative splicing. Investigating the regulatory mechanism of SE expression is hence critical to understanding its detailed function in diverse biological processes. However, little about the control of SE expression has been clarified, especially through long noncoding RNA (lncRNA). Here, we identified an antisense intragenic lncRNA transcribed from the 3' end of SE, named SEAIRa. SEAIRa repressed SE expression, which in turn led to serrated leaves. SEAIRa recruited plant U-box proteins PUB25/26 with unreported RNA binding ability and a ubiquitin-like protein related to ubiquitin 1 (RUB1) for H2A monoubiquitination (H2Aub) at exon 11 of SE. In addition, PUB25/26 helped cleave SEAIRa and release the 5' domain fragment, which recruited the PRC2 complex for H3 lysine 27 trimethylation (H3K27me3) deposition at the first exon of SE. The distinct modifications of H2Aub and H3K27me3 at different sites of the SE locus cooperatively suppressed SE expression. Collectively, our results uncover an epigenetic mechanism mediated by the lncRNA SEAIRa that modulates SE expression, which is indispensable for plant growth and development.
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Proteínas de Arabidopsis , Arabidopsis , Represión Epigenética , ARN Largo no Codificante , Proteínas de Unión al ARN , Epigénesis Genética , Histonas , ARN Largo no Codificante/genética , Proteínas de Arabidopsis/genética , Proteínas de Unión al ARN/genéticaRESUMEN
Despite many advances in treatment over the past few years, the poor 5-year survival rate and high recurrence rate of gastric cancer (GC) remain unsatisfactory. As the most abundant epigenetic modification in the eukaryotic mRNA, N6-methyladenosine (m6A) methylation participates in tumor progression and tissue development. During tumor progression, DNA damage repair mechanisms can be reprogrammed to give new growth advantages on tumor clones whose genomic integrity is disturbed. Here we detected the elevated SUV39H2 expression in GC tissues and cell lines. Functionally, SUV39H2 promoted GC proliferation and inhibited apoptosis in vitro and in vivo. Mechanistically, METTL3-mediated m6A modification promotes mRNA stability of SUV39H2 in an IGF2BP2 dependent manner, resulting in upregulated mRNA expression of SUV39H2. As a histone methyltransferase, SUV39H2 was verified to increase the phosphorylation level of ATM through transcriptional repression of DUSP6, thereby promoting HRR and ultimately inhibiting GC chemosensitivity to cisplatin. Collectively, these results indicate the specific mechanism of m6A-modified SUV39H2 as a histone methyltransferase promoting HRR to inhibit the chemosensitivity of GC. SUV39H2 is expected to become a key target in the precision targeted therapy of GC.
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Neoplasias Gástricas , Humanos , Neoplasias Gástricas/patología , Represión Epigenética , Línea Celular Tumoral , Recombinación Homóloga , Histona Metiltransferasas/genética , ARN Mensajero , Metiltransferasas/metabolismo , Proteínas de Unión al ARN/genética , Fosfatasa 6 de Especificidad Dual/genética , Fosfatasa 6 de Especificidad Dual/metabolismo , N-Metiltransferasa de Histona-Lisina/genéticaRESUMEN
The nonmineralized state of the mammalian periodontal ligament is one of the hallmarks of vertebrate evolution as it provides resilient and nontraumatic tooth anchorage for effective predation. Here we sought to determine how the chromatin state of key mineralization gene promoters contributes to the nonmineralized periodontal ligament in the midst of fully mineralized alveolar bone and cementum anchor tissues. In developing mouse periodontal tissues, RUNX2 was localized to alveolar bone-lining cells, while OSX was localized throughout the periodontal ligament's soft tissue. Matching RT-PCR amplification data and western blot comparisons demonstrated that the expression of RUNX2 and OSX bone mineralization transcription factors was at least 2.5-fold elevated in alveolar bone osteoblasts versus periodontal ligament fibroblasts. ChIP enrichment data along the RUNX2 and OSX promoters revealed increased H3K4me3 marks in alveolar bone osteoblasts, while H3K9me3 and H3K27me3 marks were elevated in periodontal ligament fibroblasts. In support of an epigenetic mechanism responsible for the inhibition of mineralization gene expression in periodontal progenitors, histone methylation inhibitors DZNep and Chaetocin reactivated RUNX2 and OSX expression in periodontal progenitors and increased alkaline phosphatase and Alizarin Red, while the in vivo application of DZNep in rat maxillae resulted in aberrant mineralization in the periodontal ligament and a narrowing of the nonmineralized periodontal space. Together, these studies demonstrate that the nonmineralized state of the mammalian periodontal ligament is controlled by an epigenetic regulation of the RUNX2 and OSX key mineralization gene promoters.
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Epigénesis Genética , Ligamento Periodontal , Animales , Ratones , Ratas , Subunidad alfa 1 del Factor de Unión al Sitio Principal/genética , Epigénesis Genética/genética , Represión Epigenética , Mamíferos/metabolismo , Ligamento Periodontal/metabolismo , Factores de Transcripción/genéticaRESUMEN
Diabetes mellitus (DM) is a chronic metabolic disease, mainly characterized by increased blood glucose and insulin dysfunction. In response to the persistent systemic hyperglycemic state, numerous metabolic and physiological complications have already been well characterized. However, its relationship to bone fragility, cognitive deficits and increased risk of dementia still needs to be better understood. The impact of chronic hyperglycemia on bone physiology and architecture was assessed in a model of chronic hyperglycemia induced by a single intraperitoneal administration of streptozotocin (STZ; 55 mg/kg) in Wistar rats. In addition, the bone-to-brain communication was investigated by analyzing the gene expression and methylation status of genes that encode the main osteokines released by the bone [Fgf23 (fibroblast growth factor 23), Bglap (bone gamma-carboxyglutamate protein) and Lcn2 (lipocalin 2) and their receptors in both, the bone and the brain [Fgfr1 (fibroblast growth factor receptor 1), Gpr6A (G-protein coupled receptor family C group 6 member A), Gpr158 (G protein-coupled receptor 158) and Slc22a17 (Solute carrier family 22 member 17)]. It was observed that chronic hyperglycemia negatively impacted on bone biology and compromised the balance of the bone-brain endocrine axis. Ultrastructural disorganization was accompanied by global DNA hypomethylation and changes in gene expression of DNA-modifying enzymes that were accompanied by changes in the methylation status of the osteokine promoter region Bglap and Lcn2 (lipocalin 2) in the femur. Additionally, the chronic hyperglycemic state was accompanied by modulation of gene expression of the osteokines Fgf23 (fibroblast growth factor 23), Bglap (bone gamma-carboxyglutamate protein) and Lcn2 (lipocalin 2) in the different brain regions. However, transcriptional regulation mediated by DNA methylation was observed only for the osteokine receptors, Fgfr1(fibroblast growth factor receptor 1) in the striatum and Gpr158 (G protein-coupled receptor 158) in the hippocampus. This is a pioneer study demonstrating that the chronic hyperglycemic state compromises the crosstalk between bone tissue and the brain, mainly affecting the hippocampus, through transcriptional silencing of the Bglap receptor by hypermethylation of Gpr158 gene.
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Factor-23 de Crecimiento de Fibroblastos , Hiperglucemia , Receptores Acoplados a Proteínas G , Animales , Ratas , Ácido 1-Carboxiglutámico/genética , Ácido 1-Carboxiglutámico/metabolismo , Huesos/metabolismo , Encéfalo/metabolismo , Represión Epigenética , Hipocampo/metabolismo , Homeostasis , Hiperglucemia/metabolismo , Lipocalina 2/metabolismo , Osteocalcina/genética , Osteocalcina/metabolismo , Ratas Wistar , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/genética , Receptor Tipo 1 de Factor de Crecimiento de Fibroblastos/metabolismo , Receptores Acoplados a Proteínas G/metabolismoRESUMEN
BACKGROUND: Protein arginine methyltransferase 6 (PRMT6) is a type I arginine methyltransferase that asymmetrically dimethylates histone H3 arginine 2 (H3R2me2a). However, the biological roles and underlying molecular mechanisms of PRMT6 in colorectal cancer (CRC) remain unclear. METHODS: PRMT6 expression in CRC tissue was examined using immunohistochemistry. The effect of PRMT6 on CRC cells was investigated in vitro and in vivo. Mass spectrometry, co-immunoprecipitation and GST pulldown assays were performed to identify interaction partners of PRMT6. RNA-seq, chromatin immunoprecipitation, Western blot and qRT-PCR assays were used to investigate the mechanism of PRMT6 in gene regulation. RESULTS: PRMT6 is significantly upregulated in CRC tissues and facilitates cell proliferation of CRC cells in vitro and in vivo. Through RNA-seq analysis, CDKN2B (p15INK4b) and CCNG1 were identified as new transcriptional targets of PRMT6. PRMT6-dependent H3R2me2a mark was predominantly deposited at the promoters of CDKN2B and CCNG1 in CRC cells. Furthermore, PRMT5 was firstly characterized as an interaction partner of PRMT6. Notably, H3R2me2a coincides with PRMT5-mediated H4R3me2s and H3R8me2s marks at the promoters of CDKN2B and CCNG1 genes, thus leading to transcriptional repression of these genes. CONCLUSIONS: PRMT6 functionally associates with PRMT5 to promote CRC progression through epigenetically repressing the expression of CDKN2B and CCNG1. These insights raise the possibility that combinational intervention of PRMT6 and PRMT5 may be a promising strategy for CRC therapy.
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Neoplasias Colorrectales , Represión Epigenética , Proteínas Nucleares , Proteína-Arginina N-Metiltransferasas , Humanos , Arginina/química , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Ciclina G1/genética , Ciclina G1/metabolismo , Regulación de la Expresión Génica , Histonas/metabolismo , Proteínas Nucleares/metabolismo , Proteína-Arginina N-Metiltransferasas/metabolismo , Represión Epigenética/genética , Inhibidor p15 de las Quinasas Dependientes de la Ciclina/metabolismoRESUMEN
Intellectual disability is a well-known hallmark of Down Syndrome (DS) that results from the triplication of the critical region of human chromosome 21 (HSA21). Major studies were conducted in recent years to gain an understanding about the contribution of individual triplicated genes to DS-related brain pathology. Global transcriptomic alterations and widespread changes in the establishment of neural lineages, as well as their differentiation and functional maturity, suggest genome-wide chromatin organization alterations in trisomy. High Mobility Group Nucleosome Binding Domain 1 (HMGN1), expressed from HSA21, is a chromatin remodeling protein that facilitates chromatin decompaction and is associated with acetylated lysine 27 on histone H3 (H3K27ac), a mark correlated with active transcription. Recent studies causatively linked overexpression of HMGN1 in trisomy and the development of DS-associated B cell acute lymphoblastic leukemia (B-ALL). HMGN1 has been shown to antagonize the activity of the Polycomb Repressive Complex 2 (PRC2) and prevent the deposition of histone H3 lysine 27 trimethylation mark (H3K27me3), which is associated with transcriptional repression and gene silencing. However, the possible ramifications of the increased levels of HMGN1 through the derepression of PRC2 target genes on brain cell pathology have not gained attention. In this review, we discuss the functional significance of HMGN1 in brain development and summarize accumulating reports about the essential role of PRC2 in the development of the neural system. Mechanistic understanding of how overexpression of HMGN1 may contribute to aberrant brain cell phenotypes in DS, such as altered proliferation of neural progenitors, abnormal cortical architecture, diminished myelination, neurodegeneration, and Alzheimer's disease-related pathology in trisomy 21, will facilitate the development of DS therapeutic approaches targeting chromatin.
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Encéfalo , Síndrome de Down , Proteína HMGN1 , Complejo Represivo Polycomb 2 , Humanos , Encéfalo/metabolismo , Cromatina/genética , Síndrome de Down/genética , Histonas , Proteína HMGN1/genética , Lisina , Complejo Represivo Polycomb 2/genética , Trisomía , Represión Epigenética/genéticaRESUMEN
Pulmonary fibrosis (PF), as an end-stage clinical phenotype of interstitial lung diseases (ILDs), is frequently initiated after alveolar injury, in which ferroptosis has been identified as a critical event aggravating the pathophysiological progression of this disease. Here in, a comprehensive analysis of two mouse models of pulmonary fibrosis developed in our lab demonstrated that lung damage-induced ferroptosis of alveolar epithelial Type2 cells (AEC2) significantly accumulates during the development of pulmonary fibrosis while ferroptosis suppressor genes GPX4 and FSP1 are dramatically inactivated. Mechanistically, upregulation of de novo methylation regulator Uhrf1 sensitively elevates CpG site methylation levels in promoters of both GPX4 and FSP1 genes and induces the epigenetic repression of both genes, subsequently leading to ferroptosis in chemically interfered AEC2 cells. Meanwhile, specific inhibition of UHRF1 highly arrests the ferroptosis formation and blocks the progression of pulmonary fibrosis in both of our research models. This study first, to our knowledge, identified the involvement of Uhrf1 in mediating the ferroptosis of chemically injured AEC2s via de novo promoter-specific methylation of both GPX4 and FSP1 genes, which consequently accelerates the process of pulmonary fibrosis. The above findings also strongly suggested Uhrf1 as a novel potential target in the treatment of pulmonary fibrosis.
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Proteínas Potenciadoras de Unión a CCAAT , Represión Epigenética , Ferroptosis , Regulación Neoplásica de la Expresión Génica , Peroxidasas , Fibrosis Pulmonar , Proteína de Unión al Calcio S100A4 , Ubiquitina-Proteína Ligasas , Animales , Ratones , Células Epiteliales Alveolares/metabolismo , Proteínas Potenciadoras de Unión a CCAAT/genética , Proteínas Potenciadoras de Unión a CCAAT/metabolismo , Ferroptosis/genética , Pulmón/patología , Fibrosis Pulmonar/genética , Ubiquitina-Proteína Ligasas/genética , Ubiquitina-Proteína Ligasas/metabolismo , Proteína de Unión al Calcio S100A4/genética , Peroxidasas/genéticaRESUMEN
BACKGROUND: Deep vein thrombosis (DVT) with its major complication, pulmonary embolism, is a global health problem. Endothelial dysfunction is involved in the pathogenesis of DVT. We have previously demonstrated that endothelial specific deletion of Brahma-related gene 1 (BRG1) ameliorates atherosclerosis and aneurysm in animal models. Whether endothelial BRG1 contributes to DVT development remains undetermined. METHODS: DVT was induced in mice by ligation of inferior vena cava. Deletion of BRG1 in endothelial cells was achieved by crossing the Cdh5-ERT-Cre mice with the Brg1loxp/loxp mice. RESULTS: Here we report that compared to the wild type mice, BRG1 conditional knockout (CKO) mice displayed substantially decreased DVT susceptibility characterized by decreased weight and size of thrombus and reduced immune infiltration. In endothelial cells, thrombomodulin (THBD) expression was significantly decreased by TNF-α stimulation, while BRG1 knockdown or inhibition recovered THBD expression. Further analysis revealed that BRG1 deficiency decreased the CpG methylation levels of the THBD promoter induced by TNF-α. Mechanistically, BRG1 directly upregulated DNMT1 expression after TNF-α treatment in endothelial cells. More importantly, administration of a small-molecule BRG1 inhibitor PFI-3 displayed potent preventive and therapeutic potentials in the DVT model. CONCLUSIONS: Our findings implicate BRG1 as an important regulator of DVT pathogenesis likely through epigenetic regulation of THBD expression in endothelial cells and provide translational proof-of-concept for targeting BRG1 in DVT intervention.
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Trombomodulina , Trombosis de la Vena , Animales , Ratones , Células Endoteliales/metabolismo , Epigénesis Genética , Represión Epigenética , Ratones Noqueados , Trombomodulina/genética , Trombomodulina/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Trombosis de la Vena/patologíaRESUMEN
It has been widely reported that dysregulated long-chain noncoding RNAs (lncRNAs) are closely associated with epilepsy. This study aimed to probe the function of lncRNA growth arrest-specific 5 (GAS5), microRNA (miR)-219 and Calmodulin-dependent protein kinase II (CaMKII)γ/N-methyl-D-aspartate receptor (NMDAR) pathway in epilepsy. Epileptic cell and animal models were constructed using magnesium deficiency treatment and diazepam injection, respectively. GAS5 and miR-219 expressions in epileptic cell and animal models were determined using qRT-PCR assay. The protein levels of CaMKIIγ, NMDAR and apoptosis-related proteins levels were assessed by western blot. Cell counting kit-8 (CCK-8) assay was employed to determine cell proliferation. Besides, TNFα, IL-1ß, IL-6 and IL-8 levels were analyzed using enzyme-linked immunosorbent assay (ELISA). Furthermore, cell apoptosis was evaluated using TUNEL staining and flow cytometric analysis. Finally, the binding relationship between GAS5 and EZH2 was verified using RIP and ChIP assay. Our results revealed that GAS5 was markedly upregulated in epileptic cell and animal models, while miR-219 was down-regulated. GAS5 knockdown dramatically increased cell proliferation of epileptic cells, whereas suppressed inflammation and the apoptosis. Furthermore, our results showed that GAS5 epigenetically suppressed transcriptional miR-219 expression via binding to EZH2. miR-219 mimics significantly enhanced cell proliferation of epileptic cells, while inhibited inflammation and the apoptosis, which was neutralized by CaMKIIγ overexpression. Finally, miR-219 inhibition reversed the effects of GAS5 silence on epileptic cells, which was eliminated by CaMKIIγ inhibition. In conclusion, GAS5 affected inflammatory response and cell apoptosis of epilepsy via inhibiting miR-219 and further regulating CaMKIIγ/NMDAR pathway (See graphic summary in Supplementary Material).
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Epilepsia , MicroARNs , ARN Largo no Codificante , Animales , Apoptosis/genética , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/genética , Proteína Quinasa Tipo 2 Dependiente de Calcio Calmodulina/metabolismo , Represión Epigenética , Epilepsia/genética , Inflamación/genética , MicroARNs/genética , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismoRESUMEN
During an immune response to microbial infection, CD8+ T cells give rise to short-lived effector cells and memory cells that provide sustained protection. Although the transcriptional programs regulating CD8+ T cell differentiation have been extensively characterized, the role of long noncoding RNAs (lncRNAs) in this process remains poorly understood. Using a functional genetic knockdown screen, we identified the lncRNA Malat1 as a regulator of terminal effector cells and the terminal effector memory (t-TEM) circulating memory subset. Evaluation of chromatin-enriched lncRNAs revealed that Malat1 grouped with trans lncRNAs that exhibit increased RNA interactions at gene promoters and gene bodies. Moreover, we observed that Malat1 was associated with increased H3K27me3 deposition at a number of memory cell-associated genes through a direct interaction with Ezh2, thereby promoting terminal effector and t-TEM cell differentiation. Our findings suggest an important functional role of Malat1 in regulating CD8+ T cell differentiation and broaden the knowledge base of lncRNAs in CD8+ T cell biology.
Asunto(s)
ARN Largo no Codificante , Linfocitos T CD8-positivos , Diferenciación Celular/genética , Represión Epigenética , Activación de Linfocitos , ARN Largo no Codificante/genéticaRESUMEN
Dysregulated epigenetic and transcriptional programming due to abnormalities of transcription factors (TFs) contributes to and sustains the oncogenicity of cancer cells. Here, we unveiled the role of zinc finger protein 280C (ZNF280C), a known DNA damage response protein, as a tumorigenic TF in colorectal cancer (CRC), required for colitis-associated carcinogenesis and Apc deficiencydriven intestinal tumorigenesis in mice. Consistently, ZNF280C silencing in human CRC cells inhibited proliferation, clonogenicity, migration, xenograft growth, and liver metastasis. As a C2H2 (Cys2-His2) zinc finger-containing TF, ZNF280C occupied genomic intervals with both transcriptionally active and repressive states and coincided with CCCTC-binding factor (CTCF) and cohesin binding. Notably, ZNF280C was crucial for the repression program of trimethylation of histone H3 at lysine 27 (H3K27me3)-marked genes and the maintenance of both focal and broad H3K27me3 levels. Mechanistically, ZNF280C counteracted CTCF/cohesin activities and condensed the chromatin environment at the cis elements of certain tumor suppressor genes marked by H3K27me3, at least partially through recruiting the epigenetic repressor structural maintenance of chromosomes flexible hinge domain-containing 1 (SMCHD1). In clinical relevance, ZNF280C was highly expressed in primary CRCs and distant metastases, and a higher ZNF280C level independently predicted worse prognosis of CRC patients. Thus, our study uncovered a contributor with good prognostic value to CRC pathogenesis and also elucidated the essence of DNA-binding TFs in orchestrating the epigenetic programming of gene regulation.
Asunto(s)
Cromatina , Neoplasias Colorrectales , Represión Epigenética , Factor de Unión a CCCTC/metabolismo , Carcinogénesis/genética , Cromatina/genética , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/metabolismo , Proteínas de Unión al ADN , Histonas/genética , Histonas/metabolismo , Humanos , Pronóstico , Factores de Transcripción , Dedos de ZincRESUMEN
The MYC oncogene is frequently amplified in triple-negative breast cancer (TNBC). Here, we show that MYC suppression induces immune-related hallmark gene set expression and tumor-infiltrating T cells in MYC-hyperactivated TNBCs. Mechanistically, MYC repressed stimulator of interferon genes (STING) expression via direct binding to the STING1 enhancer region, resulting in downregulation of the T-cell chemokines CCL5, CXCL10, and CXCL11. In primary and metastatic TNBC cohorts, tumors with high MYC expression or activity exhibited low STING expression. Using a CRISPR-mediated enhancer perturbation approach, we demonstrated that MYC-driven immune evasion is mediated by STING repression. STING repression induced resistance to PD-L1 blockade in mouse models of TNBC. Finally, a small-molecule inhibitor of MYC combined with PD-L1 blockade elicited a durable response in immune-cold TNBC with high MYC expression, suggesting a strategy to restore PD-L1 inhibitor sensitivity in MYC-overexpressing TNBC.
Asunto(s)
Proteínas de la Membrana/genética , Proteínas Proto-Oncogénicas c-myc/metabolismo , Neoplasias de la Mama Triple Negativas , Animales , Antígeno B7-H1 , Línea Celular Tumoral , Represión Epigenética , Humanos , Inhibidores de Puntos de Control Inmunológico/farmacología , Inhibidores de Puntos de Control Inmunológico/uso terapéutico , Evasión Inmune , Ratones , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Neoplasias de la Mama Triple Negativas/genética , Neoplasias de la Mama Triple Negativas/patologíaRESUMEN
Hyperimmunity drives the development of Alzheimer disease (AD). The immune system is under the circadian control, and circadian abnormalities aggravate AD progress. Here, we investigate how an AD-linked mutation deregulates expression of circadian genes and induces cognitive decline using the knock-in (KI) mice heterozygous for presenilin 2 N141I mutation. This mutation causes selective overproduction of clock gene-controlled cytokines through the DNA hypermethylation-mediated repression of REV-ERBα in innate immune cells. The KI/+ mice are vulnerable to otherwise innocuous, mild immune challenges. The antipsychotic chlorpromazine restores the REV-ERBα level by normalizing DNA methylation through the inhibition of PI3K/AKT1 pathway, and prevents the overexcitation of innate immune cells and cognitive decline in KI/+ mice. These results highlight a pathogenic link between this AD mutation and immune cell overactivation through the epigenetic suppression of REV-ERBα.