Search PubMedSearch

SEARCH · Search PubMed

Results for “Epigenetic dysregulation”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

Multi-omics analysis reveals coordinated epigenetic dysregulation in atrazine-induced dopaminergic neurotoxicity.

Atrazine (ATR), a widely used triazine herbicide, has been linked to neurotoxicity, yet the epigenetic mechanisms underlying its dopaminergic effects remain unclear. This study investigated whether coordinated miRNA dysregulation and DNA methylation alterations contribute to ATR-induced Parkinson's disease (PD)-like neurotoxicity. Male Sprague-Dawley rats were administered ATR (50&#x202f;mg/kg/day) for 90 days, resulting in motor and cognitive deficits with dopaminergic dysfunction, including increased &#x3b1;-synuclein and reduced tyrosine hydroxylase expression. Small RNA sequencing identified 72 differentially expressed miRNAs in the substantia nigra, enriched in PI3K-Akt, MAPK, and Ras signaling pathways. In a cohort of six PD patients and six matched controls, genome-wide DNA methylation profiling revealed 4694 differentially methylated positions, predominantly hypomethylated, with overlapping enrichment in neuronal signaling pathways. Weighted gene co-expression network analysis identified a PD-associated module strongly correlated with disease status (r&#x202f;=&#x202f;-0.95, P&#x202f;<&#x202f;0.001). Multi-omics integration identified CASP3 as a central hub gene. External validation supported CASP3 relevance in PD (AUC&#x202f;=&#x202f;0.833), and molecular docking suggested potential ATR-CASP3 interaction. Further analysis predicted upregulated miR-3552 as a potential upstream regulator of CASP3. These findings indicate that ATR-induced neurotoxicity may be mediated through the miR-3552/CASP3 signaling axis, ultimately regulating apoptosis and contributing to neurodegeneration.

Animals

DNA Methylation and Proteomic Profiling of Postmortem Brain Tissue Reveals Epigenetic Dysregulation and Neuroinflammatory in Fragile X-associated Tremor/Ataxia Syndrome (FXTAS).

BACKGROUND: Fragile X-associated Tremor/Ataxia Syndrome (FXTAS) is a late-onset neurodegenerative disorder caused by FMR1 premutation CGG repeat expansions (55-200 repeats). The epigenetic landscape of the FXTAS brain remains uncharacterized. We performed genome-wide DNA methylation profiling of postmortem prefrontal cortex tissue to identify differentially methylated positions (DMPs) and candidate genes, and sought protein-level support for a neuroinflammatory signal. METHODS: DNA methylation was profiled in postmortem prefrontal cortex (Brodmann area 9) from 27 male FXTAS cases and 29 male controls using the Illumina MethylationEPIC array (EPICv1 and EPICv2 platforms), merging 721,802 common probes. Surrogate variable analysis (SVA) controlled for confounders. DMPs were defined by |&#x394;&#x3b2;| > 0.10 and FDR < 0.05; exploratory Reactome 2024 pathway analysis was performed on the DMP-associated gene list. Targeted proteomic profiling was performed in the same brain region using the Olink (proximity extension assay) Inflammation panel in 9 FXTAS cases and 12 controls, with SVA-adjusted differential abundance analysis, and concordance assessment against a prior mass spectrometry dataset. RESULTS: We identified 108 significant cg-type DMPs mapping to 80 genes (50 hypermethylated, 58 hypomethylated in FXTAS). The strongest signal was CYP2E1 (7 concordant hypomethylated DMPs, mean &#x394;&#x3b2; = -0.143), an oxidative stress gene also implicated in Parkinson's disease. FTCD, a one-carbon cycle enzyme, carried 5 hypermethylated DMPs (mean &#x394;&#x3b2; = +0.210). A cluster of DMP-associated genes with established roles in innate immune and NF-&#x3ba;B signaling, TRAF3 (the single most significant DMP among the inflammation genes, hypermethylated), BATF, RCOR1, and MSI2; they pointed toward neuroinflammatory dysregulation. Additional genes included LINGO1 (myelination inhibitor), SYT3 (synaptic vesicle), and SLC39A4 (zinc transporter). Exploratory Reactome enrichment using the DMP-associated gene set nominated themes including neuroinflammation resolution, axonal growth inhibition, zinc homeostasis, and CYP2E1 metabolism at nominal significance (p<0.05); however, the gene-to-pathway mapping rate was low and no pathway survived correction for multiple testing. Olink proteomic analysis independently identified 60 significantly altered inflammation proteins (59 downregulated), including CXCL8, CXCL10, IL6, IL15, IL18, TLR3, IRAK1/4, and complement C1QA, which were directionally concordant with prior mass spectrometry data. CONCLUSIONS: This integrated study reveals a genome-wide epigenetic signature in the FXTAS prefrontal cortex implicating oxidative stress, myelination failure, zinc dysregulation, one-carbon cycle disruption, and most notably a coordinated set of epigenetically altered genes governing innate immune and NF-&#x3ba;B signaling. Convergence of TRAF3 hypermethylation with independent downregulation of TLR3 and NF-&#x3ba;B-pathway proteins at the protein level supports a coherent, cross-platform model of dysregulated neuroinflammatory signaling in FXTAS, identified here through individual gene- and protein-level convergence rather than formal pathway enrichment. FTCD hypermethylation proposes a self-reinforcing epigenetic loop via SAM depletion. These multi-omic findings establish FXTAS as a disorder of pervasive epigenetic reprogramming and nominate candidate genes for future mechanistic and therapeutic investigation.

CYP2E1

Maternal transfer of nonylphenol drives oxidative, immune, and epigenetic dysregulation in zebrafish offspring.

Nonylphenol (NP), a widespread surfactant and endocrine-disrupting pollutant, poses significant ecological and public health risks globally; however, its transgenerational effects remain poorly understood. Using zebrafish (Danio rerio), we compared chronic maternal NP exposure (50 and 100 &#xb5;g/L, 28 days) with acute embryonic exposure (0.22 &#xb5;mol/L) during 0-3 days post-fertilization (dpf) to delineate mechanistic differences in toxicity. Maternal NP exposure produced severe developmental defects in offspring, including edema, axial curvature, impaired swim bladder inflation, reduced growth, cardiac dysfunction, and decreased viability. These phenotypes were accompanied by systemic molecular disruptions including oxidative stress, altered estrogen receptor (ER) expression, dysregulated mitogen-activated protein kinase (MAPK) signaling, and suppressed innate immune response characterized by attenuated neutrophil/macrophage density, reduced CD68 and complement protein C3 expression, diminished nitrite load, and downregulation of pro-inflammatory mediators at both transcript and protein levels. Maternal exposure further induced apoptosis and persistent epigenetic reprogramming (alterations in DNA methylation and histone-modifying enzymes), hallmarks of transgenerational toxicity. In contrast, direct embryonic NP exposure elicited morphological abnormalities without significant lethality, accompanied by induction of pro-inflammatory cytokines, nitric oxide (NO) synthesis, and MAPK activation, reflecting an augmented inflammatory response. These mechanistic contrasts reveal that maternal NP exposure is a potent driver of systemic, heritable molecular reprogramming, whereas embryonic exposure triggers acute inflammatory pathways. Together, our findings underscore the global relevance of NP as a transgenerational toxicant, advocating for its urgent inclusion in ecotoxicological risk assessments and regulatory frameworks.

Animals

Splenic extramedullary hematopoiesis in myelofibrosis is shaped by transcriptomic and epigenetic dysregulation.

Myelofibrosis (MF) is a chronic, progressive myeloproliferative neoplasm characterized by bone marrow fibrosis, ineffective blood cell production, and neoplastic extramedullary hematopoiesis (EMH) occurring primarily within the spleen. To explore the molecular mechanisms underlying splenic EMH, we performed single-cell transcriptional and chromatin profiling of cells from MF spleens that had been surgically removed. We demonstrate significant expansion of hematopoietic stem and progenitor cells, coupled with aberrant differentiation toward the erythroid and megakaryocytic lineages, associated with a significant enrichment of inflammatory pathways with enhanced NF-&#x3ba;B signaling and IFN responses, as well as dysregulation of the inferred function of differentiation-defining transcription factors. Finally, we report a significant remodeling of the immune microenvironment in MF spleens, characterized by emergence of dysfunctional T cell subsets and inflammatory memory B cells, suggesting the concomitant establishment of a pro-inflammatory and immune-tolerant tumor microenvironment within the spleen that influences hematopoietic cell differentiation and impairs tumor immune surveillance.

Primary Myelofibrosis

Epigenetic alterations induced by ionizing radiation: pathways to cancer and prognostic strategies.

PURPOSE: Ionizing radiation (IR) is widely used not only in cancer diagnosis and therapy, but its biological effects also extend beyond radiation-induced lethal lesions, e.g., specifically DNA double-strand breaks (DNA-DSBs). This review aims to summarize current evidence on IR-induced epigenetic alterations and to integrate mechanistic insights from radiation chemistry and radiation biology that link DNA damage to long-term epigenetic dysregulation. RESULTS: Experimental and clinical studies collectively show that IR induces persistent epigenetic reprogramming, including global and gene-specific DNA methylation changes, radiation-responsive histone modifications, chromatin remodeling, and dysregulation of non-coding RNAs. Aberrant RNA methylation, including modifications like N6-methyladenosine (m6A), 5-methylcytosine (m5C), N1-methyladenosine (m1A), N7-methylguanine (m7G), and N3-methylcytosine (m3C), is closely linked to tumorigenesis and progression. Due to its tumor-specific properties, RNA methylation markers, specifically m6A, m5C, m1A, m7G, and m3C, emerge as valuable markers in liquid biopsy. Radiation chemistry studies indicate that epigenetically modified bases, for example, m5C, are preferential targets of radiation-induced oxidative damage, thereby promoting mutational hotspots and genomic instability. By altering DNA repair, apoptosis, immune responses, and cellular differentiation, these epigenetic changes promote carcinogenesis, radioresistance, and tissue toxicity. CONCLUSION: IR-induced epigenetic alterations represent a critical interface between initial DNA damage and long-term biological outcomes. Improved understanding of radiation-associated epigenetic signatures may enhance risk assessment, inform prognostic stratification, and support the development of epigenetic-targeted strategies to optimize radiotherapy and reduce adverse effects.

Ionizing radiation

Integrated Genomic and Epigenomic Analysis Reveals Epigenetic Plasticity in Disease Progression and Multidrug Resistance in Multiple Myeloma.

UNLABELLED: Multiple myeloma is marked by recurrent cytogenetic abnormalities and mutations that accumulate as the disease progresses. In this study, we sought to elucidate the transitions driving tumorigenesis and therapy resistance in multiple myeloma using a unique cohort of nearly 900 patients spanning premalignant to late-stage refractory multiple myeloma, comprehensively characterized at molecular and clinical levels. Waves of epigenetic dysregulation drove these critical transitions. In this paradigm, genomic and cytogenetic events unlocked epigenetic plasticity, reshaping multiple myeloma cell biology to evade tumor microenvironment constraints and therapeutic pressures. Functional perturbation studies in an isogenic proteasome inhibitor-resistant cell line model demonstrated enhanced reliance on transcriptional cofactors, supporting a mechanistic link between chromatin plasticity and therapy adaptation. Collectively, these findings support a unifying framework in which genomic heterogeneity unlocks gene regulatory plasticity, enabling plasma cells (PC) to evade microenvironmental constraints and therapeutic pressure. These results provide a mechanistic explanation for sequential relapse without new genomic alterations and nominate epigenetic plasticity-mediated PC adaptation as a therapeutic vulnerability in the heterogeneous genetic background of multiple myeloma. SIGNIFICANCE: Assembly and analysis of a multiple myeloma cohort spanning the continuum from premalignant to late relapse that integrates bulk transcriptomics with single-cell multiomic data provides insights into disease progression and epigenetic plasticity.

Multiple Myeloma

Changes of DNA methylation and gene expression profile in placental villi and chorioamniotic membranes under preeclampsia.

BACKGROUND: Preeclampsia (PE) is a serious pregnancy complication with elusive pathogenesis. Although epigenetic dysregulation is implicated, its layer-specific placental roles are poorly defined. This study aimed to identify shared and layer-specific epigenetic alterations in PE by profiling DNA methylation and gene expression in placental villi (PV) and chorioamniotic membranes (CAM). RESEARCH DESIGN AND METHODS: PV and CAM samples were collected from 7 normal and 8 PE pregnancies, and three public DNA methylation datasets (GSE98224, GSE44667, GSE75196) were integrated. Differentially methylated genes (DMGs) and differentially expressed genes (DEGs) were identified based on whole-genome methylation and transcriptome sequencing. Layer-specific and shared gene sets were identified by cross-analysis, with functional annotation using Gene Ontology (GO). RESULTS: EM-seq revealed a hypermethylation-dominant, tissue-specific methylation landscape in PE placentas. Cross-tissue comparison identified shared DMGs between the two layers, including nine key genes consistently altered in public datasets. Integrated analysis in PV further identified 22 co-dysregulated genes, enriched in thermoregulation, maternal-fetal immunity, signal transduction, and cell differentiation. CONCLUSIONS: This study elucidates the shared and layer-specific dysregulation of gene networks at methylomic and transcriptomic levels in PE placenta. Comparing PV and CAM highlights placental epigenetic heterogeneity and dysfunction, offering novel clues for mechanistic research and layer-targeted therapies.

Humans

Redistribution of super-enhancers promotes malignancy in human hepatocellular carcinoma.

INTRODUCTION: Super-enhancers (SEs) are defined as the regulatory region where intensive transcriptional cofactors bind. Dysregulation of SEs is related to multiple diseases, however, its role in hepatocellular carcinoma (HCC) remains elusive. OBJECTIVES: This work aimed to reveal the dysregulation of SEs in HCC and the therapeutic potential for HCC treatment. METHODS: Fifteen HCC and twelve paracancerous samples underwent chromatin immunoprecipitation (ChIP) sequencing targeting H3K27ac, and subsequently the SEs were identified by the Rank Ordering of Super-Enhancers algorithm. Differential SEs featured by tumor or paracancerous tissues were identified, and cross-referenced with the differential expression genes and prognosis-related genes in 2 independent public or in-house HCC cohorts. The SE region of HSPA4 was deleted in the genome of HCCLM3 cell by CRISPR-Cas9, named HSPA4-SE-KO cells. The potential druggable transcriptional factors were identified by CRCmapper, GeneMANIA and Drug Gene Interaction Database (DGID). RESULTS: Five targets, including CDKN2C, HSPA4, GGH, PDGFA, and CAP2, were identified as HCC-gain SEs with oncogenic potential, which were further validated experimentally by SE inhibitors and ChIP targeting H3K27ac and BRD4. Cell proliferation and migration assays further confirmed that silencing of these HCC-gain SEs significantly suppressed the malignant phenotype of HCC cell lines. HSPA4 appeared strongest oncogenic functions among these targets, which was further verified by HCC mouse xenograft models and clinical sample investigation. Moreover, HSPA4-SE-KO cells obtained significantly suppressed HSPA4 expression and retarded tumorigenic capability. Finally, dysregulation of transcriptional factors engaged in the oncogenic role of SEs, and Danthron that targeting RXRA were identified from DGID for HCC treatment. CONCLUSION: The dysregulated SE landscape of HCC promoted the malignancy phenotype by the upregulation of oncogenes, and SE-regulatory network might be potential drug targets for HCC treatment. Our study deepened the insight of epigenetic dysregulation in HCC, offering the groundwork for SEs as potential therapeutic targets of HCC treatment.

Humans

Epigenetics and In Silico Transcriptome Analysis of Pediatric Acute Myeloid Leukemia.

Pediatric acute myeloid leukemia (AML) is a heterogeneous hematologic malignancy that accounts for about 15%-20% of childhood leukemias. Despite therapeutic advances, relapses remain common, and survival for high-risk patients is below 60%. Unlike adult AML, pediatric AML displays distinct genetic mutations, including FLT3-ITD, NPM1, KMT2A rearrangements, and core-binding factors (CBF) fusions, as well as extensive epigenetic dysregulation. Aberrant DNA methylation, histone modifications, and altered non-coding RNA expressions disrupt hematopoietic differentiation and activate oncogenic transcriptional networks. Recent advances in silico transcriptomic analysis have transformed the study of pediatric AML by integrating gene expression and epigenetic data to identify molecular drivers and regulatory networks. Computational RNA-seq pipelines and pathway analyses have highlighted key epigenetic regulators, including DNMT3A, TET2, and HDACs, as potential therapeutic targets. Multi-omics approaches combining transcriptomic, methylomic, and chromatin accessibility data are increasingly used to define biomarkers for diagnosis, prognosis, and therapeutic response. This review provides a comprehensive overview of the molecular and epigenetic landscape of pediatric AML, emphasizing the power of in silico transcriptome analysis to uncover disease mechanisms, refine patient stratification, and guide the development of precision-based epigenetic therapies aimed at improving long-term outcomes in children with AML.

Humans

Defining active and repressive chromatin states in neural crest cells using low-input CUT&RUN.

The transition of neural crest cells (NCCs) from a multipotent state to lineage-restricted derivatives, including melanocytes, is governed by tightly regulated epigenetic mechanisms that orchestrate cell type specific gene expression programs. Histone post-translational modifications (PTMs), in particular, play an important role in modulating chromatin accessibility, enhancer activation, and transcription factor occupancy, thereby facilitating dynamic chromatin and transcriptional reprogramming required during development. However, profiling such chromatin states in rare and transient Neural Crest Cell (NCC) populations in vivo remains technically challenging. To address this, we present an optimized low-input Cleavage Under Targets and Release Using Nuclease (CUT&RUN) workflow tailored for fluorescence-activated cell sorting (FACS) isolated NCCs from zebrafish embryos. This approach enables high-resolution and low-background mapping of key histone modifications, including H3K27ac, H3K4me3, and H3K27me3, from limited cell numbers. Collectively, these methodologies provide a robust framework for dissecting chromatin state dynamics in developmental systems and can also offer insights into epigenetic dysregulation associated with disease.

Animals

Epigenetic orchestration of cancer-immune dynamics: mechanisms, technologies, and clinical advancements.

BACKGROUND: Epigenetic dysregulation plays a pivotal role in cancer immune evasion by orchestrating tumour antigen silencing, immune cell dysfunction, and the formation of an immunosuppressive microenvironment. By disrupting successive phases of the cancer-immunity cycle-from antigen presentation to T cell exhaustion-these aberrations facilitate immune escape and tumour progression, highlighting the need for targeted epigenetic intervention. AIM OF REVIEW: This review systematically dissects how epigenetic alterations impair anti-tumour immunity at each stage of the CI cycle. It not only integrates fragmented mechanistic evidence but also emphasizes underexplored crosstalk between specific epigenetic regulators and immune cell types. It further highlights emerging technologies-such as single-cell epigenomics, spatial multi-omics, and CRISPR-based screens-that are driving discovery of novel therapeutic targets and refining patient stratification. Key scientific concepts of review. We discuss how epigenetic interventions, alone or in combination with immunotherapies, can reinvigorate immune responses and overcome resistance to current treatments. A particular focus is given to how integrative high-resolution platforms are mapping immunoepigenetic landscapes, enabling mechanism-informed, precision immunotherapy strategies. By bridging epigenetic regulation with translational immuno-oncology, this review outlines a future where epigenetic reprogramming becomes central to overcoming immune evasion in cancer.

Humans

Mechanisms of Hematopoietic Stem Cell Aging and Emerging Rejuvenation Strategies.

Hematopoietic stem cell (HSCs) aging is a complex biological process driven by both cell-intrinsic alterations and extrinsic cues from the bone marrow niche. Understanding these mechanisms is critical for developing therapies against aging-related hematopoietic disorders. This review synthesizes recent advances in the molecular mechanisms underlying HSCs aging, including microenvironmental aging, genomic instability, epigenetic dysregulation, mitochondrial dysfunction, and aberrant nuclear mechanotransduction. We summarize that the functional decline of HSCs during aging drives a compensatory expansion of the phenotypically defined stem cell pool, leading to an aberrant increase in cell number. We also highlight aging-associated HSCs heterogeneity, including CD150high and P-selectin-positive subsets that enrich for myeloid-biased or functionally compromised HSCs states while emphasizing that surface phenotype alone may not fully indicate functional rejuvenation. Finally, we discuss emerging rejuvenation strategies-including targeting myeloid-biased HSCs, modulating inflammatory pathways, and implementing epigenetic or metabolic interventions-supported by cutting-edge technologies such as single-cell multi-omics, gene editing, and computational modeling. These approaches hold promise for counteracting age-related hematopoietic decline and restoring immune competence.

Humans

Cell-type-specific DNA methylation dynamics in the prenatal and postnatal human cortex.

The human cortex undergoes extensive epigenetic remodeling during development, although the precise temporal and cell-type-specific dynamics of DNA methylation remain incompletely understood. In this study, we profiled genome-wide DNA methylation across human cortex tissue from donors aged 6 post-conception weeks to 108 years of age. We observed widespread, developmentally regulated changes in DNA methylation, with pronounced shifts occurring during early- and mid-gestation that were distinct from age-associated modifications in the postnatal cortex. Using fluorescence-activated nuclei sorting, we optimized a protocol for the isolation of SATB2-positive neuronal nuclei, enabling the identification of cell-type-specific DNA methylation trajectories in the developing cortex. Developmentally dynamic DNA methylation sites were significantly enriched near genes implicated in autism and schizophrenia, supporting a role for epigenetic dysregulation in neurodevelopmental conditions. Our findings underscore the prenatal period as a critical window of epigenomic plasticity in the brain with important implications for understanding the genetic basis of neurodevelopmental phenotypes.

Humans

Maternal age as a driver of genome instability: mechanisms linking aneuploidy, mutagenesis and mitochondrial dysfunction.

Advanced maternal age is a well-established risk factor for adverse reproductive outcomes due to increased rates of aneuploidy. However, emerging evidence indicates that the genetic consequences of maternal aging extend well beyond chromosome mis-segregation. Aging oocytes acquire a broad spectrum of genetic abnormalities, including maternally derived nuclear de novo mutations (DNMs) and mitochondrial DNA mutations, together with epigenetic dysregulation of DNA methylation and post-translational modification levels. These changes reflect the unique biology of the female germline in which oocytes remain arrested in meiotic prophase I for decades. Age-related deterioration of key processes, such as erosion of cohesion complexes, altered meiotic recombination, and weakened spindle assembly checkpoint surveillance collectively destabilize meiotic chromosome architecture, directly driving chromosome mis-segregation. At the same time, accumulation of endogenous DNA damage and declining DNA damage and repair processes increase the chances of transmitting lesions that can be converted into sequence-level mutations during the earliest embryonic divisions, when genome maintenance relies exclusively on maternal factors. High-resolution sequencing studies further demonstrate that maternal aging is associated with increased DNMs burden in both nuclear and mitochondrial DNA. Together, these findings support a model in which maternal aging is a driver of genome-wide instability that links aneuploidy and mutagenesis through shared defects in meiotic surveillance, declining DNA repair efficiency, and mitochondrial function. This framework positions delayed childbearing as a multifaceted genetic risk factor that extend beyond aneuploidy to include mutations and other genomic alterations that can impact intergenerational genetic risk.

Aneuploidy

Identification of compounds that repress DUX4 expression in facioscapulohumeral muscular dystrophy.

Facioscapulohumeral muscular dystrophy (FSHD) is caused by epigenetic dysregulation of the disease locus, leading to pathogenic misexpression of DUX4 in skeletal muscle. Thus, most FSHD therapeutic approaches target DUX4. Our previous study identified the chromatin remodeling factor BAZ1A (bromodomain adjacent to zinc finger domain protein 1A) as a promising target for therapeutic development. Here we used an artificial intelligence-based screening pipeline to identify molecules predicted to bind the BAZ1A bromodomain, and validated hit compounds using FSHD-specific assays in FSHD myocytes. One compound, termed C06, emerged as a potent repressor of DUX4 and DUX4 target gene expression. Interestingly, while C06 exhibited binding to BAZ1A in vitro, it can also inhibit multiple kinases, including p38&#x3b1;, an upstream activator of DUX4. Despite this, at low doses C06 was an equally effective and more specific repressor of DUX4 than losmapimod, which is a robust and specific p38 inhibitor. At low concentrations, C06 returns the DUX4 gene expression signature to a healthier profile without major effects on the muscle transcriptome. Thus, C06 is a useful tool for potent and specific DUX4 suppression, and a viable candidate for further development. Our results highlight both the utility and limitations of AI for targeted drug discovery, and the importance of using an FSHD-specific functional screening strategy for selecting relevant candidates.

Muscular Dystrophy, Facioscapulohumeral

Loss-of-function in RBBP5 results in a syndromic neurodevelopmental disorder associated with microcephaly.

PURPOSE: Epigenetic dysregulation has been associated with many inherited disorders. RBBP5 (HGNC:9888) encodes a core member of the protein complex that methylates histone 3 lysine-4 and has not been implicated in human disease. METHODS: We identify 5 unrelated individuals with de novo heterozygous variants in RBBP5. Three nonsense/frameshift and 2 missense variants were identified in probands with neurodevelopmental symptoms, including global developmental delay, intellectual disability, microcephaly, and short stature. Here, we investigate the pathogenicity of the variants through protein structural analysis and transgenic Drosophila models. RESULTS: Both missense p.(T232I) and p.(E296D) variants affect evolutionarily conserved amino acids located at the interface between RBBP5 and the nucleosome. In Drosophila, overexpression analysis identifies partial loss-of-function mechanisms when the variants are expressed using the fly Rbbp5 or human RBBP5 cDNA. Loss of Rbbp5 leads to a reduction in brain size. The human reference or variant transgenes fail to rescue this loss and expression of either missense variant in an Rbbp5 null background results in a less severe microcephaly phenotype than the human reference, indicating both missense variants are partial loss-of-function alleles. CONCLUSION: Haploinsufficiency of RBBP5 observed through de novo null and hypomorphic loss-of-function variants is associated with a syndromic neurodevelopmental disorder.

Humans

Driver genomic lesions in MDM2, CDK4, and JUN co-opt targetable super-enhancer networks to impose liposarcomagenic core regulatory circuitry.

INTRODUCTION: Amplification of chromosome 12q13-15 spanning MDM2 and CDK4 genes serves as a molecular diagnostic hallmark of dedifferentiated liposarcoma (DDLPS), an aggressive soft-tissue sarcoma. Epigenetic activation of master transcription factors (RUNX proteins, FOSL2, and MYC) establishes a self-reinforcing oncogenic transcriptional circuitry in DDLPS. Nevertheless, the collaborative interplay between genomic alterations and epigenetic dysregulation in defining DDLPS cell identity remains elusive. OBJECTIVES: This work aimed to elucidate the primary genetic drivers and mechanistic basis of DDLPS-specific core transcriptional regulatory circuitry. METHODS: We performed integrative chromatin profiling analysis of DDLPS clinical specimens and cell lines to map cis-regulatory landscapes. Cistromes of MDM2, JUN, and E2F1 were delineated through chromatin immunoprecipitation sequencing in two DDLPS models. Essential driver functions and transcriptional regulatory effects of key regulators were assessed via various genetic manipulation approaches. Synergistic interactions between BET-targeting agents and MDM2/p53 or CDK4 inhibitors were quantified by cell viability assays. In vivo xenograft assays evaluated the oncogenic potential of key regulators and the therapeutic efficacy of novel strategies. RESULTS: Co-amplification of MDM2, CDK4, and JUN during sarcomagenesis converges with BET protein-dependent chromatin remodeling to fuel feed-forward transcriptional circuits among master transcription factors. Mechanistically, excessively expressed MDM2 stabilizes the core regulatory circuitry by forming chromatin-bound complexes with JUN/FOSL2 at cis-regulatory elements, especially super-enhancers across DDLPS genome. Concurrently, CDK4 maintains expression of E2F1 which further fosters transcriptional output of master transcription factors in DDLPS cells. Leveraging DDLPS-selective overexpression of MDM2 and its E3 ligase activity, targeted degradation of BET proteins by MDM2-recruiting proteolysis targeting chimera selectively disrupted the core regulatory circuitry, suppressing DDLPS growth and exhibiting strong synergy with CDK4 inhibitor. CONCLUSION: DDLPS-associated genomic lesions collaborate with BET-dependent chromatin regulation to establish disease-sustaining transcriptional circuitry. Our findings also provide a mechanistic rationale for harnessing MDM2's E3 ligase activity to therapeutically degrade oncoproteins in MDM2-amplified malignancies.

Core transcriptional regulatory circuitry

HeteroGeNETics: Neuroendocrine tumor genetics reflect their heterogeneous complex diversity.

Neuroendocrine neoplasms (NENs) comprise a diverse group of malignancies arising across multiple anatomical sites and displaying remarkable biological and clinical heterogeneity. While advances in sequencing have identified recurrent genetic alterations in several NEN subtypes, these tumors remain largely characterized by a relatively low mutational burden and lack of dominant oncogenic drivers. Consequently, emerging evidence suggests that the molecular basis of neuroendocrine tumorigenesis extends beyond individual mutations and involves broader processes such as chromatin remodeling, telomere maintenance, epigenetic dysregulation and cellular plasticity. This review aims to summarize the current molecular landscape of pulmonary, gastro-enteropancreatic and thymic NENs, focusing on the biological pathways and cellular programs disrupted by recurrent genetic alterations unrelated to syndromes. We discuss how multi-omic studies have refined molecular classification and revealed common principles underlying neuroendocrine tumor development. Collectively, recent literature supports a shift from mutation-centered models toward a more integrated understanding of the complex biology and evolution of NENs.

genomics