Chromatin Gene Research Articles

Pharmacological Advancements of PRC2 in Cancer Therapy: A Narrative Review

Polycomb repressive complex 2 (PRC2) is known to regulate gene expression and chromatin structure as it methylates H3K27, resulting in gene silencing. Studies have shown that PRC2 has dual functions in oncogenesis that allow it to function as both an oncogene and a tumor suppressor. Because of this, nuanced strategies are necessary to promote or inhibit PRC2 activity therapeutically. Given the therapeutic vulnerabilities and associated risks in oncological applications, a structured literature review on PRC2 was conducted to showcase similar cofactor competitor inhibitors of PRC2. Key inhibitors such as Tazemetostat, GSK126, Valemetostat, and UNC1999 have shown promise for clinical use within various studies. Tazemetostat and GSK126 are both highly selective for wild-type and lymphoma-associated EZH2 mutants. Valemetostat and UNC1999 have shown promise as orally bioavailable and SAM-competitive inhibitors of both EZH1 and EZH2, giving them greater efficacy against potential drug resistance. The development of other PRC2 inhibitors, particularly inhibitors targeting the EED or SUZ12 subunit, is also being explored with the development of drugs like EED 226. This review aims to bridge gaps in the current literature and provide a unified perspective on promising PRC2 inhibitors as therapeutic agents in the treatment of lymphomas and solid tumors.

A STAG2-PAXIP1/PAGR1 axis suppresses lung tumorigenesis.

The cohesin complex is a critical regulator of gene expression. STAG2 is the most frequently mutated cohesin subunit across several cancer types and is a key tumor suppressor in lung cancer. Here, we coupled somatic CRISPR-Cas9 genome editing and tumor barcoding with an autochthonous oncogenic KRAS-driven lung cancer model and showed that STAG2 is uniquely tumor-suppressive among all core and auxiliary cohesin components. The heterodimeric complex components PAXIP1 and PAGR1 have highly correlated effects with STAG2 in human lung cancer cell lines, are tumor suppressors in vivo, and are epistatic to STAG2 in oncogenic KRAS-driven lung tumorigenesis in vivo. STAG2 inactivation elicits changes in gene expression, chromatin accessibility, and 3D genome conformation that impact the cancer cell state. Gene expression and chromatin accessibility similarities between STAG2- and PAXIP1-deficient neoplastic cells further relate STAG2-cohesin to PAXIP1/PAGR1. These findings reveal a STAG2-PAXIP1/PAGR1 tumor-suppressive axis and uncover novel PAXIP1-dependent and PAXIP1-independent STAG2-cohesin-mediated mechanisms of lung tumor suppression.

Single-nucleus multi-omics analyses reveal cellular and molecular innovations in the anterior cingulate cortex during primate evolution.

The anterior cingulate cortex (ACC) of the human brain is involved in higher-level cognitive functions such as emotion and self-awareness. We generated profiles of human and macaque ACC gene expression and chromatin accessibility at single-nucleus resolution. We characterized the conserved patterns of gene expression, chromatin accessibility, and transcription factor binding in different cell types. Combining the published mouse data, we discovered the molecular identities and cell-lineage origin of the primate von Economo neurons (VENs). Our invitro and invivo experiments identified a group of primate-shared and human-specific VEN marker genes, such as PCSK6, ADAMTSL3, and CDHR3, potentially contributing to VEN morphogenesis. We demonstrated that the human-specific sequence changes account for the cellular and functional innovations in the ACC during primate evolution and human origin. These findings provide new insights into understanding the cellular composition and molecular regulation of ACC and its evolutionary role in shaping human-owned higher cognitive skills.

Multiome Perturb-seq unlocks scalable discovery of integrated perturbation effects on the transcriptome and epigenome.

Single-cell CRISPR screens link genetic perturbations to transcriptional states, but high-throughput methods connecting these induced changes to their regulatory foundations are limited. Here, we introduce Multiome Perturb-seq, extending single-cell CRISPR screens to simultaneously measure perturbation-induced changes in gene expression and chromatin accessibility. We apply Multiome Perturb-seq in a CRISPRi screen of 13 chromatin remodelers in human RPE-1 cells, achieving efficient assignment of sgRNA identities to single nuclei via an improved method for capturing barcode transcripts from nuclear RNA. We organize expression and accessibility measurements into coherent programs describing the integrated effects of perturbations on cell state, finding that ARID1A and SUZ12 knockdowns induce programs enriched for developmental features. Modeling of perturbation-induced heterogeneity connects accessibility changes to changes in gene expression, highlighting the value of multimodal profiling. Overall, our method provides a scalable and simply implemented system to dissect the regulatory logic underpinning cell state. A record of this paper's transparent peer review process is included in the supplemental information.

Genome-wide association studies and multi-omics integrative analysis reveal novel loci and their molecular mechanisms for circulating polyunsaturated, monounsaturated, and saturated fatty acids.

Previous genome-wide association studies (GWAS) have identified genetic loci associated with the circulating levels of FAs, but the biological mechanisms of these genetic associations remain largely unexplored. Here, we conducted GWAS to identify additional genetic loci for 19 circulating fatty acid (FA) traits in UK Biobank participants of European ancestry (N = 239,268) and five other ancestries (N = 508 - 4,663). We leveraged the GWAS findings to characterize genetic correlations and colocalized regions among FAs, explore sex differences, examine FA loci influenced by lipoprotein metabolism, and apply statistical fine-mapping to pinpoint putative causal variants. We integrated GWAS signals with multi-omics quantitative trait loci (QTL) to reveal intermediate molecular phenotypes mediating the associations between the genetic loci and FA levels. Altogether, we identified 215 significant loci for polyunsaturated fatty acids (PUFAs)-related traits in European participants, 163 loci for monounsaturated fatty acids (MUFAs)-related traits, and 119 loci for saturated fatty acids (SFAs)-related traits, including 70, 61, and 54 novel loci, respectively. A novel locus for total FAs, the percentage of omega-6 PUFAs in total FAs, and total MUFAs (around genes GSTT1/2/2B ) overlapped with QTL signals for all six molecular phenotypes examined, including gene expression, protein abundance, DNA methylation, splicing, histone modification, and chromatin accessibility. Across 19 FA traits, 65% of GWAS loci overlapped with QTL signals for at least one molecular phenotype. Our study identifies novel genetic loci for circulating FA levels and systematically uncovers their underlying molecular mechanisms.

Pooled CRISPR screens with joint single-nucleus chromatin accessibility and transcriptome profiling.

Pooled single-cell CRISPR screens have profiled either gene expression or chromatin accessibility but not both modalities. Here we develop MultiPerturb-seq, a high-throughput CRISPR screening platform with joint single-nucleus chromatin accessibility, transcriptome and guide RNA capture using combinatorial indexing combined with droplet microfluidics to scale throughput and integrate all three modalities. We identify key differentiation genes in a rare pediatric cancer and establish ZNHIT1 as a potential target for cancer reprogramming therapy.

RADIP technology comprehensively identifies H3K27me3-associated RNA-chromatin interactions.

Many RNAs associate with chromatin, either directly or indirectly. Several technologies for mapping regions where RNAs interact across the genome have been developed to investigate the function of these RNAs. Obtaining information on the proteins involved in these RNA-chromatin interactions is critical for further analysis. Here, we developed RADIP [RNA and DNA interacting complexes ligated and sequenced (RADICL-seq) with immunoprecipitation], a novel technology that combines RADICL-seq technology with chromatin immunoprecipitation to characterize RNA-chromatin interactions mediated by individual proteins. Building upon the foundational principles of RADICL-seq, RADIP extends its advantages by increasing genomic coverage and unique mapping rate efficiency compared to existing methods. To demonstrate its effectiveness, we applied an anti-H3K27me3 antibody to the RADIP technology and generated libraries from mouse embryonic stem cells (mESCs). We identified a multitude of RNAs, including RNAs from protein-coding genes and non-coding RNAs, that are associated with chromatin via H3K27me3 and that likely facilitate the spread of Polycomb repressive complexes over broad regions of the mammalian genome, thereby affecting gene expression, chromatin structures and pluripotency of mESCs. Our study demonstrates the applicability of RADIP to investigations of the functions of chromatin-associated RNAs.

Abstract IA025: A DNA methylation atlas of normal human cell types

Abstract DNA methylation is a fundamental epigenetic mark that governs gene expression and chromatin organization, thus providing a window into cellular identity and developmental processes. Current datasets typically include only a fraction of methylation sites and are often based either on cell lines that underwent massive changes in culture or on tissues containing unspecified mixtures of cells. Here we describe a human methylome atlas, based on deep whole-genome bisulfite sequencing, allowing fragment-level analysis across thousands of unique markers for 39 cell types sorted from 205 healthy tissue samples. Replicates of the same cell type are more than 99.5% identical, demonstrating the robustness of cell identity programmes to environmental perturbation. Unsupervised clustering of the atlas recapitulates key elements of tissue ontogeny and identifies methylation patterns retained since embryonic development. Loci uniquely unmethylated in an individual cell type often reside in transcriptional enhancers and contain DNA binding sites for tissue-specific transcriptional regulators. Uniquely hypermethylated loci are rare and are enriched for CpG islands, Polycomb targets and CTCF binding sites, suggesting a new role in shaping cell-type-specific chromatin looping. The atlas provides an essential resource for study of gene regulation and disease-associated genetic variants, and a wealth of potential tissue-specific biomarkers for use in liquid biopsies. Citation Format: Tommy Kaplan. A DNA methylation atlas of normal human cell types [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr IA025.

Single cell variant to enhancer to gene map for coronary artery disease.

Although genome wide association studies (GWAS) in large populations have identified hundreds of variants associated with common diseases such as coronary artery disease (CAD), most disease-associated variants lie within non-coding regions of the genome, rendering it difficult to determine the downstream causal gene and cell type. Here, we performed paired single nucleus gene expression and chromatin accessibility profiling from 44 human coronary arteries. To link disease variants to molecular traits, we developed a meta-map of 88 samples and discovered 11,182 single-cell chromatin accessibility quantitative trait loci (caQTLs). Heritability enrichment analysis and disease variant mapping demonstrated that smooth muscle cells (SMCs) harbor the greatest genetic risk for CAD. To capture the continuum of SMC cell states in disease, we used dynamic single cell caQTL modeling for the first time in tissue to uncover QTLs whose effects are modified by cell state and expand our insight into genetic regulation of heterogenous cell populations. Notably, we identified a variant in the COL4A1 / COL4A2 CAD GWAS locus which becomes a caQTL as SMCs de-differentiate by changing a transcription factor binding site for EGR1/2. To unbiasedly prioritize functional candidate genes, we built a genome-wide single cell variant to enhancer to gene (scV2E2G) map for human CAD to link disease variants to causal genes in cell types. Using this approach, we found several hundred genes predicted to be linked to disease variants in different cell types. Next, we performed genome-wide Hi-C in 16 human coronary arteries to build tissue specific maps of chromatin conformation and link disease variants to integrated chromatin hubs and distal target genes. Using this approach, we show that rs4887091 within the ADAMTS7 CAD GWAS locus modulates function of a super chromatin interactome through a change in a CTCF binding site. Finally, we used CRISPR interference to validate a distal gene, AMOTL2 , liked to a CAD GWAS locus. Collectively we provide a disease-agnostic framework to translate human genetic findings to identify pathologic cell states and genes driving disease, producing a comprehensive scV2E2G map with genetic and tissue level convergence for future mechanistic and therapeutic studies.

Functional and Practical Insights Into the Genetic Basis of Takayasu Arteritis.

Takayasu arteritis (TAK) is a rare vasculitis characterized by inflammation of large arteries. Although the exact etiology of TAK remains unclear, a genetic predisposition to the disease has been established. Large-scale genetic studies have significantly contributed to the identification of genetic variation associated with immune-mediated diseases. To date, five genome-wide association studies (GWAS) have been performed in TAK, identifying multiple genetic susceptibility loci across the genome. Here, we summarize the major findings from GWAS in TAK and provide an in silico functional evaluation of the associated loci (P < 5 × 10-8) and variants in high linkage disequilibrium with them (r2 > 0.8). By exploring gene expression and chromatin interaction data, we identified candidate causal genes in TAK, some of them with well-known functional implications. The analysis of transcription factor motifs within TAK-associated loci revealed enrichment of the STAT and RUNX families, both characterized by their role in immune functions and inflammatory responses. The enrichment in biological processes in susceptibility loci confirmed the involvement of specific immune-related pathways in TAK. Further, we devised and calculated a cumulative genetic risk score for TAK and confirmed differences in genetic risk for the disease among ancestries. Finally, we provide a practical guide to communicate genetic information for TAK to patients and families.

E2F3a activates Gadd45b gene expression through PPARα-mediated transcriptional regulation in hepatic cells

Growth arrest and DNA damage-inducible beta (GADD45b) plays a critical role in intracellular events such as cell growth and apoptosis. Although the functional study of GADD45b has been conducted, the mechanism for the transcriptional regulation of GADD45b is largely unknown. Due to the drastic induction of hepatic GADD45b mRNA by peroxisome proliferator-activated receptor alpha (PPARα) activation in wild-type mice, we investigated a key factor that affects the upregulation of GADD45b mRNA. Interestingly, we found that GADD45b-promoter luciferase activity was dramatically increased as the 5’-flanking regions were closer to the transcription start site (TSS) in Hepa1c1c7 cells. Additionally, we found two E2F (E2F-myc activator/cell cycle regulator) binding motifs in the region (-150/-1) of the GADD45b promoter. Notably, E2F3 mRNA was significantly increased only in wild-type mice treated with WY-14643, a PPARα agonist, followed by the induction of GADD45b mRNA. Furthermore, gene functional studies and Chromatin Immunoprecipitation (ChIP) assays revealed that E2F3 could regulate the GADD45b gene via the E2F binding motif. Thus, we suggest that E2F3 may play a key role in regulating the GADD45b gene as a positive transcription factor.

Exploring lncRNA expression in follicular fluid exosomes of patients with obesity and polycystic ovary syndrome based on high-throughput sequencing technology

BackgroundInfertility is a reproductive health problem that attracts worldwide attention. Polycystic ovary syndrome (PCOS) is a major cause of female infertility and patients with obesity and PCOS are particularly common in clinical practice. Long non-coding RNA (lncRNAs) are a functional core in cells that regulate gene expression, transcription, and chromatin modification processes, and participate in epigenetics, cell cycle, and cell differentiation. LncRNAs are assumed to play a role in the occurrence and development of PCOS; however, their specific mechanism of action remains to be elucidated.MethodsHigh-throughput sequencing technology has been used to sequence and analyze lncRNAs in exosomes from the follicular fluid of patients with obesity and PCOS and those who underwent assisted reproductive therapy owing to male factors. Specific expression profiles of patients with obesity and PCOS were obtained and functional information analysis combined with a literature review were performed to screen for differentially expressed lncRNAs, which were validated using real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR).ResultsHigh-throughput sequencing analysis revealed that compared to normal patients with male infertility, patients with obesity and PCOS had a total of 20 lncRNAs with significant expression differences in follicular fluid exosomes. Among them, 17 lncRNAs were upregulated and three were downregulated. Functional analysis showed that differentially expressed genes were mainly enriched in “cell metabolism,” “cell adhesion,” and other aspects: related gene pathways mainly involved Huntington’s disease, Parkinson’s disease, spliceosomes, non-alcoholic fatty liver disease, and ribosomes. Verification of differentially expressed lncRNAs revealed that the expression of lncRNAs TPT1-AS1, PTOV1-AS1, PTPRG-AS1, and SNHG14 in follicular fluid exosomes was consistent with the sequencing results.ConclusionA preliminary differential expression profile of lncRNAs in exosomes of patients with obesity and PCOS was established by transcriptomic analysis of these individuals. Our bioinformatics analysis results may be applicable to further study of the impact mechanism involving obesity and PCOS. These differentially expressed lncRNAs maybe served as potential biomarkers for in-depth studies of the occurrence, development on Follicle quality and function for patients with PCOS in the future.

The Arabidopsis blue-light photoreceptor CRY2 is active in darkness to inhibit root growth.

Cryptochromes (CRYs) are blue-light receptors that regulate diverse aspects of plant growth. However, whether and how non-photoexcited CRYs function in darkness or non-blue-light conditions is unknown. Here, we show that CRY2 affects the Arabidopsis transcriptome even in darkness, revealing a non-canonical function. CRY2 suppresses cell division in the root apical meristem to downregulate root elongation in darkness. Blue-light oligomerizes CRY2 to de-repress root elongation. CRY2 physically interacts with FORKED-LIKE 1 (FL1) and FL3, and these interactions are inhibited by blue light, with only monomeric but not dimeric CRY2 able to interact. FL1 and FL3 associate with the chromatin of cell division genes to facilitate their transcription. This pro-growth activity is inhibited by CRY2's physical interaction with FLs in darkness. Plants have evolved to perceive both blue-light and dark cues to coordinate activation and repression of competing developmental processes in above- and below-ground organs through economical and dichotomous use of ancient light receptors.

Spatial Transcriptomics and Single-Nucleus Multi-Omics Analysis Revealing the Impact of High Maternal Folic Acid Supplementation on Offspring Brain Development.

Background: Folate, an essential vitamin B9, is crucial for diverse biological processes, including neurogenesis. Folic acid (FA) supplementation during pregnancy is a standard practice for preventing neural tube defects (NTDs). However, concerns are growing over the potential risks of excessive maternal FA intake. Objectives/Methods: Here, we employed a mouse model and spatial transcriptomic and single-nucleus multi-omics approaches to investigate the impact of high maternal FA supplementation during the periconceptional period on offspring brain development. Results: Maternal high FA supplementation affected gene pathways linked to neurogenesis and neuronal axon myelination across multiple brain regions, as well as gene expression alterations related to learning and memory in thalamic and ventricular regions. Single-nucleus multi-omics analysis revealed that maturing excitatory neurons in the dentate gyrus (DG) are particularly vulnerable to high maternal FA intake, leading to aberrant gene expressions and chromatin accessibility in pathways governing ribosomal biogenesis critical for synaptic formation. Conclusions: Our findings provide new insights into specific brain regions, cell types, gene expressions and pathways that can be affected by maternal high FA supplementation.

Comprehensive Analysis and Verification of the Prognostic Significance of Cuproptosis-Related Genes in Colon Adenocarcinoma.

Colon adenocarcinoma (COAD) is a frequently occurring and lethal cancer. Cuproptosis is an emerging type of cell death, and the underlying pathways involved in this process in COAD remain poorly understood. Transcriptomic and clinical data for COAD patients were collected from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases. We investigated alterations in DNA and chromatin of cuproptosis-related genes (CRGs) in COAD. In order to identify predictive differentially expressed genes (DEGs) and various molecular subtypes, we used consensus cluster analysis. Through univariate, multivariate, and Lasso Cox regression analyses, four CRGs were identified. A risk prognostic model for cuproptosis characteristics was constructed based on four CRGs. This study also examined the association between the risk score and the tumor microenvironment (TME), the immune landscape, and drug sensitivity. We distinguished two unique molecular subtypes using consensus clustering analysis. We discovered that the clinical characteristics, prognosis, and TME cell infiltration characteristics of patients with multilayer CRG subtypes were all connected. The internal and external evaluations of the predicted accuracy of the prognostic model built using data derived from a cuproptosis risk score were completed at the same time. A nomogram and a clinical pathological analysis make it more useful in the field of medicine. A significant rise in immunosuppressive cells was observed in the high cuproptosis risk score group, with a correlation identified between the cuproptosis risk score and immune cell infiltration. Despite generally poor prognoses, the patients with a high cuproptosis risk but low tumor mutation burden (TMB), cancer stem cell (CSC) index, or microsatellite instability (MSI) may still benefit from immunotherapy. Furthermore, the cuproptosis risk score positively correlated with immune checkpoint gene expression. Analyzing the potential sensitivity to medications could aid in the development of clinical chemotherapy regimens and decision-making. CRGs are the subject of our in-depth study, which exposed an array of regulatory mechanisms impacting TME. In addition, we performed additional data mining into clinical features, prognosis effectiveness, and possible treatment medications. COAD's molecular pathways will be better understood, leading to more precise treatment options.

High-throughput development and characterization of new functional nanobodies for gene regulation and epigenetic control in human cells.

Controlling gene expression and chromatin state via the recruitment of transcriptional effector proteins to specific genetic loci has advanced the potential of mammalian synthetic biology, but is still hindered by the challenge of delivering large chromatin regulators. Here, we develop a new method for generating small nanobodies against human chromatin regulators that can repress or activate gene expression. We start with a large and diverse nanobody library and perform enrichment against chromatin regulatory complexes using yeast display, followed by high-throughput pooled selection for transcriptional control when recruited to a reporter in human cells. This workflow allows us to efficiently select tens of functional nanobodies that can act as transcriptional repressors or activators in human cells.

Heart tube morphogenesis is regulated by segment-specific gene regulatory networks controlled by MEF2C.

The transcription factor MEF2C plays a critical role in the development of the linear heart tube, but the specific transcriptional networks controlled by MEF2C remain largely undefined. To address this, we performed combined single-nucleus RNA-and ATAC-sequencing on wild type and MEF2C-null embryos at distinct stages of development. We identified a broadly "posteriorized" cardiac gene signature and chromatin landscape throughout the heart tube in the absence of MEF2C. By integrating our gene expression and chromatin accessibility data in a deep-learning based model, we were able to construct developmental trajectories for each of the outflow tract, ventricular, and inflow tract lineages and determined how each of these segment-specific trajectories were distinctly altered in the MEF2C-null embryos. We computationally identified potential segment-specific MEF2C-dependent enhancers, and from these candidates, identified novel enhancers with activity in the developing heart tube using transgenesis in zebrafish. Finally, using inferred gene regulatory networks we discovered a genetic interaction between Mef2c and the atrial nuclear hormone receptor Nr2f2 , revealing that the MEF2C-null heart malformations are partly driven by a transcriptional network with increased NR2F2 activity. These studies not only provide a rich description of the genomic regulation of early heart tube development, but provide a generalizable framework for using genetic mutants to dissect the transcriptional networks that govern developmental processes.

Chromatin structure and 3D architecture define the differential functions of PU.1 regulatory elements in blood cell lineages

The precise spatiotemporal expression of the hematopoietic ETS transcription factor PU.1, a key determinant of hematopoietic cell fates, is tightly regulated at the chromatin level. However, how chromatin signatures are linked to this dynamic expression pattern across different blood cell lineages remains uncharacterized. Here, we performed an in-depth analysis of the relationships between gene expression, chromatin structure, 3D architecture, and trans-acting factors at PU.1 cis-regulatory elements (PCREs). By identifying phylogenetically conserved DNA elements within chromatin-accessible regions in primary human blood lineages, we discovered multiple novel candidate PCREs within the upstream region of the human PU.1 locus. A subset of these elements localizes within an 8-kb-wide cluster exhibiting enhancer features, including open chromatin, demethylated DNA, enriched enhancer histone marks, present enhancer RNAs, and PU.1 occupation, presumably mediating PU.1 autoregulation. Importantly, we revealed the presence of a common 35-kb-wide CTCF-flanked insulated neighborhood that contains the PCRE cluster (PCREC), forming a chromatin territory for lineage-specific and PCRE-mediated chromatin interactions. These include functional PCRE-promoter interactions in myeloid and B cells that are absent in erythroid and T cells. By correlating chromatin structure and 3D architecture with PU.1 expression in various lineages, we were able to attribute enhancer versus silencer functions to individual elements. Our findings provide mechanistic insights into the interplay between dynamic chromatin structure and 3D architecture in the chromatin regulation of PU.1 expression. This study lays crucial groundwork for additional experimental studies that validate and dissect the role of PCREs in epigenetic regulation of normal and malignant hematopoiesis.

Integrated Single-Cell Multiomic Profiling of Caudate Nucleus Suggests Key Mechanisms in Alcohol Use Disorder.

Alcohol use disorder (AUD) induces complex transcriptional and regulatory changes across multiple brain regions including the caudate nucleus, which remains understudied. Using paired single-nucleus RNA-seq and ATAC-seq on caudate samples from 143 human postmortem brains, including 74 with AUD, we identified 17 distinct cell types. We found that a significant portion of the alcohol-induced changes in gene expression occurred through altered chromatin accessibility. Notably, we identified novel transcriptional and chromatin accessibility differences in medium spiny neurons, impacting pathways such as RNA metabolism and immune response. A small cluster of D1/D2 hybrid neurons showed distinct differences, suggesting a unique role in AUD. Microglia exhibited distinct activation states deviating from classical M1/M2 designations, and astrocytes entered a reactive state partially regulated by JUND , affecting glutamatergic synapse pathways. Oligodendrocyte dysregulation, driven in part by OLIG2 , was linked to demyelination and increased TGF-β1 signaling from microglia and astrocytes. We also observed increased microglia-astrocyte communication via the IL-1β pathway. Leveraging our multiomic data, we performed cell type-specific expression quantitative trait loci analysis, integrating that with public genome-wide association studies to identify AUD risk genes such as ADAL and PPP2R3C , providing a direct link between genetic variants, chromatin accessibility, and gene expression in AUD. These findings not only provide new insights into the genetic and cellular mechanisms in the caudate related to AUD but also demonstrate the broader utility of large-scale multiomic studies in uncovering complex gene regulation across diverse cell types, which has implications beyond the substance use field.

Differential chromatin accessibility and transcriptional dynamics define breast cancer subtypes and their lineages

Breast cancer (BC) is defined by distinct molecular subtypes with different cells of origin. The transcriptional networks that characterize the subtype-specific tumor-normal lineages are not established. In this work, we applied bulk, single-cell and single-nucleus multi-omic techniques as well as spatial transcriptomics and multiplex imaging on 61 samples from 37 patients with BC to show characteristic links in gene expression and chromatin accessibility between BC subtypes and their putative cells of origin. Regulatory network analysis of transcription factors underscored the importance of BHLHE40 in luminal BC and luminal mature cells and KLF5 in basal-like tumors and luminal progenitor cells. Furthermore, we identify key genes defining the basal-like (SOX6 and KCNQ3) and luminal A/B (FAM155A and LRP1B) lineages. Exhausted CTLA4-expressing CD8+ T cells were enriched in basal-like BC, suggesting an altered means of immune dysfunction. These findings demonstrate analysis of paired transcription and chromatin accessibility at the single-cell level is a powerful tool for investigating cancer lineage and highlight transcriptional networks that define basal and luminal BC lineages.