The UCSC Genome Browser database: 2025 update

Dissecting the shared molecular mechanisms underlying polycystic ovary syndrome and schizophrenia etiology: a translational integrative approach

Recent evidence suggests that individuals with polycystic ovary syndrome (PCOS) have an increased risk of developing mental health disorders and comorbidities linked to nervous system dysfunction. Interestingly, patients with schizophrenia (SCZ) often exhibit PCOS symptoms, indicating a possible connection between the two conditions. However, the underlying molecular links between these diseases remain poorly understood. We employed a comprehensive in-silico approach, utilizing publicly available datasets to investigate shared biomarkers candidates and key regulators involved in the development of PCOS and SCZ. We retrieved the datasets from the NCBI GEO database and differentially expressed genes (DEGs) were identified for each dataset. Common DEGs (cDEGs) were determined, and transcription factors (TFs) and miRNA targeting cDEGs were examined using the mirDIP portal and TRRUST database, respectively. We also assessed the TF-miRNA interactions by TransmiR database and constructed a regulatory network including TFs-microRNAs-cDEGs. Our analysis identified a total of 15 cDEGs that are regulated by 15 TFs and 8 mRNAs. Among our findings, we prioritized RELA as a potential TF regulator for both diseases, demonstrating synergistic interaction with four cDEGs (EGR1, CXCL8, IL1RN, IL1B) and seven microRNAs (hsa-miR-580, hsa-miR-5695, hsa-miR-936, hsa-miR-3675, hsa-miR-634, hsa-miR-603, hsa-miR-222) that target these genes. Our data highlights potential common biomarkers for PCOS and SCZ, presenting a novel regulatory network that elucidates the molecular mechanisms underlying both conditions. This emphasizes the importance of further research to explore new translational approaches, which may ultimately lead to improved diagnostic and therapeutic strategies for affected individuals.

C-terminal binding protein 2 interacts with JUNB to control macrophage inflammation

Although acute inflammatory responses are critical for survival, chronic inflammation is a leading cause of disease and mortality worldwide. Nevertheless, our mechanistic understanding of pathogenesis is still limited and precise treatment options are lacking. Here, we investigate the role of the transcriptional co-repressors C-terminal binding protein (CTBP) 1 and 2 in murine and human macrophage activation using loss-of-function models to show that CTBP2 but not CTBP1 controls inflammatory gene expression. We find that CTBP2 occupies cis-regulatory elements of inflammatory genes together with the transcription factors NF-κB and AP-1 and forms a co-repressor complex. Rescue of Ctbp1/2 double knockout cells with WT, oligomeric CTBP2 attenuates inflammatory responses, whereas a monomeric mutant does not. Differential profiling of CTBP2's WT and monomeric interactome confirms oligomer-specific interactions with multiple repressors. Conversely, monomers retain the ability to interact with AP-1 and RNA polymerase II, boosting gene expression. Our findings point to an important function for CTBP2 in fine-tuning inflammatory gene expression, potentially unveiling novel therapeutic targets for the treatment of inflammatory diseases.

Interallelic gene conversion of leukemia-associated single nucleotide variants

CRISPR-Cas9 is a useful tool for inserting precise genetic alterations through homology-directed repair (HDR), although current methods largely rely on provision of an exogenous repair template. Here, we tested the possibility of interchanging heterozygous single nucleotide variants (SNVs) using mutation-specific guide RNA, and the cell's own wild-type allele rather than an exogenous template. Using high-fidelity Cas9 to perform allele-specific CRISPR across multiple human leukemia cell lines as well as in primary hematopoietic cells from patients with leukemia, we find high levels of reversion to wild-type in the absence of exogenous template. Moreover, we demonstrate that bulk treatment to revert a truncating mutation in ASXL1 using CRISPR-mediated interallelic gene conversion (IGC) is sufficient to prolong survival in a human cell line-derived xenograft model (median survival 33 days vs 27.5 days; p = 0.0040). These results indicate that IGC is a useful laboratory tool which can be applied to numerous types of leukemia and can meaningfully alter cellular phenotypes at scale. Because our method targets single-base mutations, rather than larger variants targeted by IGC in prior studies, it greatly expands the pool of genetic lesions which could potentially be targeted by IGC. This technique may reduce cost and complexity for experiments modeling phenotypic consequences of SNVs. The principles of SNV-specific IGC demonstrated in this proof-of-concept study could be applied to investigate the phenotypic effects of targeted clonal reduction of leukemogenic SNV mutations.

Bath: a Bayesian approach to analyze epigenetic transitions reveals a dual role of H3K27me3 in chondrogenesis

BACKGROUND

Histone modifications are key epigenetic regulators of cell differentiation and have been intensively studied in many cell types and tissues. Nevertheless, we still lack a thorough understanding of how combinations of histone marks at the same genomic location, so-called chromatin states, are linked to gene expression, and how these states change in the process of differentiation. To receive insight into the epigenetic changes accompanying the differentiation along the chondrogenic lineage we analyzed two publicly available datasets representing (1) the early differentiation stages from embryonic stem cells into chondrogenic cells and (2) the direct differentiation of mature chondrocyte subtypes.

RESULTS

We used ChromHMM to define chromatin states of 6 activating and repressive histone marks for each dataset and tracked the transitions between states that are associated with the progression of differentiation. As differentiation-associated state transitions are likely limited to a reduced set of genes, one challenge of such global analyses is the identification of these rare transitions within the large-scale data. To overcome this problem, we have developed a relativistic approach that quantitatively relates transitions of chromatin states on defined groups of tissue-specific genes to the background. In the early lineage, we found an increased transition rate into activating chromatin states on mesenchymal and chondrogenic genes while mature chondrocytes are mainly enriched in transition between activating states. Interestingly, we also detected a complex extension of the classical bivalent state (H3K4me3/H3K27me3) consisting of several activating promoter marks besides the repressive mark H3K27me3. Within the early lineage, mesenchymal and chondrogenic genes undergo transitions from this state into active promoter states, indicating that the initiation of gene expression utilizes this complex combination of activating and repressive marks. In contrast, at mature differentiation stages the inverse transition, the gain of H3K27me3 on active promoters, seems to be a critical parameter linked to the initiation of gene repression in the course of differentiation.

CONCLUSIONS

Our results emphasize the importance of a relative analysis of complex epigenetic data to identify chromatin state transitions associated with cell lineage progression. They further underline the importance of serial analysis of such transitions to uncover the diverse regulatory potential of distinct histone modifications like H3K27me3.

Starvation activates ECM-remodeling gene transcription and putative enhancers in fibroblasts despite inducing quiescence

Depletion of growth factors and nutrients induces cellular quiescence, which often accompanies transcriptional silencing and chromatin compaction. Paradoxically, such depletion occurs in pathological microenvironments in which fibroblasts are activated to orchestrate tissue remodeling. The relationship between fibroblast activation and growth factor and nutrient depletion remains unclear. Here, we report that serum depletion in cell culture, a model for growth factor and nutrient depletions, extensively activates transcription in fibroblasts despite inducing quiescence. Activated genes were enriched for extracellular matrix (ECM) structural components and proteases. ECM-related transcription accompanied the activation of putative distal enhancers but not promoters. The activated putative enhancers were enriched for non-coding variants associated with inflammatory bowel disease (IBD) risk, suggesting an alteration in the ECM-remodeling gene regulatory network in IBD. This study implicates nutrient and growth factor depletion in activating the ECM-remodeling gene program in fibroblasts, challenging the prevailing view linking such depletion to transcriptional dormancy.

IPMK depletion influences genome-wide DNA methylation

Inositol polyphosphate multikinase (IPMK) is emerging as a critical regulator of nuclear functions. While earlier studies in yeast and cell lines linked IPMK to gene expression, recent work reveals its role in modulating histone acetylation through the activation of histone deacetylases 1/3 (HDAC1/3). Interestingly, HDAC1/3 interact with DNA methyltransferase 1 (DNMT1), stabilizing DNMT1 and promoting DNA methylation. As an HDAC1/3 activator, IPMK may thereby influence DNA methylation dynamics. This study investigates how the genetic depletion of IPMK influences DNA methylation, though the role of its kinase activity remains untested. Using long-read Oxford nanopore sequencing, we conducted methylation analysis for >28 millions of CpG sites and discovered that IPMK deletion results in over 22,000 differentially methylated regions (DMRs). Integrating affected genes by DMRs and RNA-seq data, we found that 35 genes show an inverse correlation between methylation in promoter regions and gene expression. Pathway analysis revealed that genes related to tissue remodeling and hematopoiesis are affected. Notably, MMP14 and LIF showed significant methylation changes in promoter regions under IPMK deletion, resulting in decreased mRNA and protein expression. Collectively, this study identifies IPMK as a novel regulator of DNA methylation. While this study did not investigate the role of IPMK's kinase activity in regulating DNA methylation, future studies will determine whether IPMK's effects on DNA methylation are driven by its kinase activity or by kinase-independent mechanisms.

Synaptic activity causes minute-scale changes in BAF complex composition and function

Genes encoding subunits of the BAF ATP-dependent chromatin remodeling complex are among the most enriched for deleterious de novo mutations in intellectual disabilities and autism spectrum disorder, but the causative molecular pathways are not understood. Synaptic activity in neurons is critical for learning, memory, and proper neural development. While BAF is required for activity-dependent developmental processes, such as dendritic outgrowth, the immediate molecular consequences of neuronal activity on BAF complexes are unknown. Here, we report that neuronal activity induces dramatic remodeling of the subunit composition of BAF complexes within 15 min, concurrent with both phosphorylation and dephosphorylation of its subunits. These biochemical effects are a convergent phenomenon downstream of multiple calcium-activated signaling pathways in mouse neurons and mouse fibroblasts and correspond to changes in BAF-dependent chromatin accessibility. Our studies imply that BAF decodes signals at the membrane by altering the combinatorial composition of its subunits.

Axenfeld-Rieger syndrome associated with a megabase-scale inversion separating PITX2 from a conserved enhancer locus

Axenfeld-Rieger Syndrome (ARS) is an autosomal dominant condition with both ocular and non-ocular manifestations. ARS is primarily caused by coding variants at the PITX2 or FOXC1 loci, yet many cases still remain undiagnosed. Here we used whole-genome sequencing to identify two non-coding structural variants associated with a typical presentation of PITX2-associated ARS: one with a 450 kb deletion removing a series of conserved enhancer elements distal to PITX2, and the second with a 12.5 Mb inversion displacing the PITX2 gene from these same enhancer elements. Neither variant disrupted the PITX2 gene itself, and therefore both were expected to reduce PITX2 expression by disrupting its proximity or access to enhancer elements. Enhancer-disrupting intergenic inversions therefore represent a unique genetic mechanism for the development of ARS, which should be carefully considered in the context of ARS and other conditions without a conclusive genetic diagnosis.

Focus on single gene effects limits discovery and interpretation of complex trait-associated variants

Standard QTL mapping approaches consider variant effects on a single gene at a time, despite abundant evidence for allelic pleiotropy, where a single variant can affect multiple genes simultaneously. While allelic pleiotropy describes variant effects on both local and distal genes or a mixture of molecular effects on a single gene, here we specifically investigate allelic expression "proxitropy": where a single variant influences the expression of multiple, neighboring genes. We introduce a multi-gene eQTL mapping framework- cis -principal component expression QTL ( cis -pc eQTL or pcQTL)-to identify variants associated with shared axes of expression variation across a cluster of neighboring genes. We perform pcQTL mapping in 13 GTEx human tissues and discover novel loci undetected by single-gene approaches. In total, we identify an average of 1396 pcQTLs/tissue, 27% of which were not discovered by single-gene methods. These novel pcQTL colocalized with an additional 142 GWAS trait-associated variants and increased the number of colocalizations by 34% over single-gene QTL mapping. These findings highlight that moving beyond single-gene-at-a-time approaches toward multi-gene methods can offer a more comprehensive view of gene regulation and complex trait-associated variation.

The ABCs of the H2Bs: The histone H2B sequences, variants, and modifications

Histone proteins are the building blocks of chromatin, and function by wrapping DNA into complex structures that control gene expression. Histone proteins are regulated by post-translational modifications (PTMs) and by histone variant exchange. In this review, we will provide an overview of one of these histones: H2B. We will first define the sequences of human and mouse H2B proteins and discuss potential designations for canonical H2B. We will also describe the differential functions of H2B variants compared with canonical H2B. Finally, we will summarize known H2B modifications and their functions in regulating transcription. Through review of H2B genes, proteins, variants, and modifications, we aim to highlight the importance of H2B for epigenetic and transcriptional regulation of the cell.

miRNA and piRNA differential expression profiles in Alzheimer's disease: A potential source of pathology and tool for diagnosis

Alzheimer's Disease (AD) is the most prevalent form of dementia and one of the leading causes of death in the United States, and despite our best efforts and recent advancements, a treatment that stops or substantially slows its progression has remained elusive. Small extracellular vesicles (sEVs), hold the potential to alleviate some of the common issues in the field by serving to better differentiate AD and non-AD individuals. These vesicles could provide insights into therapeutic targets, and potentially an avenue towards early detection. We compared the sEV cargo profiles of AD and non-AD brains (n = 6) and identified significant differences in both the micro RNA (miRNA) and Piwi-interacting RNA (piRNA) cargo through sEV isolation from temporal cortex tissue, followed by small RNA sequencing, and differential expression analysis. Differentially expressed miRNAs targeting systems relevant to AD included miR-206, miR-4516, miR-219a-5p, and miR-486-5p. Significant piRNAs included piR-6,565,525, piR-2,947,194, piR-7,181,973, and piR-7,326,987. These targets warrant further study for their potential role in the progression of AD pathology by dysregulating cellular activity; additionally, future large-scale studies of neuronal sEV miRNA profiles may facilitate the development of diagnostic tools which can aid in clinical trial design and recruitment. Longitudinal analysis of sEV data, perhaps accessible through plasma surveyance, will help determine at what point these miRNA and/or piRNA profiles begin to diverge between AD and non-AD individuals.

A comprehensive transcriptome based meta-analysis to unveil the aggression nexus of oral squamous cell carcinoma

Lymph node metastasis in oral cancer (OC) complicates management due to its aggressive nature and high risk of recurrence, underscoring the need for biomarkers for early detection and targeted therapies. However, the drivers of this aggressive phenotype remain unclear due to the variability in gene expression patterns. To address this, an integrative meta-analysis of six publicly available transcriptomic profiles, categorized by lymph nodal status, is conducted. Key determinants of disease progression are identified through functional characterization and the TopConfects ranking approach of nodal associated differentially expressed genes (DEGs). To explore the critical nexus between lymph node metastasis and OC recurrence, significant metastatic genes were cross-analysed with literature-derived genes exhibiting aberrant methylation patterns in OC recurrence. Their clinical relevance and expression patterns were then validated in an external dataset from the TCGA head and neck cancer cohort. The analysis identified elevated expression of genes involved in extracellular matrix remodelling and immune response, while the expression of genes related to cellular differentiation and barrier functions was reduced, driving the transition to nodal positivity. The highest-ranked gene, MMP1, showed a log-fold change (LFC) of 4.946 (95 % CI: 3.71, 6.18) in nodal-negative samples, which increased to 5.899 (95 % CI: 4.80, 6.99) in nodal-positive samples, indicating consistent elevation across disease stages. In contrast, TMPRSS11B was significantly downregulated, with an LFC of -5.512 (95 % CI: -6.63, -4.38) in nodal-negative samples and -5.898 (95 % CI: -7.15, -4.64) in nodal-positive samples. Furthermore, MEIS1, down-regulated in nodal-positive status, was found to exhibit hypermethylation at CpG sites associated with OC recurrence. This study represents the first transcriptomic meta-analysis to explore the intersection of lymph node metastasis and OC recurrence, identifying MEIS1 as a potential key contributor. These comprehensive insights into disease trajectories offer potential biomarkers and therapeutic targets for future treatment strategies.

Lysine Demethylase 5B Alleviates Neuroinflammation in Ischemic Stroke by Repressing Steap4

Six-transmembrane epithelial antigen of prostate 4 (Steap4) has been suggested as a potential marker for reactive astrocytes. This investigation focuses on the role of Steap4 in ischemic stroke (IS) and its regulator in this context. A mouse model of IS was generated using middle cerebral artery occlusion (MCAO). Additionally, mouse astrocytes that underwent oxygen-glucose deprivation (OGD) were utilized for in vitro investigations. Steap4 was found to be upregulated in the brain of MCAO-challenged mice and OGD-challenged astrocytes. Steap4 silencing reduced infarct size and alleviated IS-associated pathological exacerbations in mice, as well as ameliorated A1 skewing of astrocytes and inflammatory cytokine secretion both in vivo and in vitro. Lysine demethylase 5B (Kdm5b), identified as an upstream regulator of Steap4, was poorly expressed in IS/OGD models. Kdm5b overexpression repressed Steap4 transcription by removing H3K4me3 modification, thus alleviating pro-inflammatory activation of astrocytes and neuroinflammation. However, Kdm5b's protective effects were diminished upon Steap4 restoration in mice or astrocytes. In conclusion, this study suggests that the loss of Kdm5b leads to aberrant upregulation of Steap4, contributing to pro-inflammatory activation of astrocytes and brain damage in IS.

N-glycosylated LTβR increases the Th17/Treg cell ratio in liver cancer by blocking RORC ubiquitination and FOXP3 transcription

LTβR-overexpressing CAR-T cells have demonstrated surprising effectiveness against solid tumors, exhibiting strong anti-exhaustion and proliferation capabilities. However, the role of LTβR in CD4+ T cell differentiation and anti-tumor activity remains unclear. In this study, we employed primary or subcutaneous mouse hepatocellular carcinoma (HCC) models and flow cytometry to study the impact of conditional knock-in of Ltbr on CD4+ T cell differentiation and response, particularly the Th17/Treg cell ratio, and its influence on HCC progression. Immunoprecipitation, immunoblotting, RT-qPCR, molecular docking, and Chromatin Immunoprecipitation-qPCR were performed to investigate the molecular mechanism of CD4+ T cell differentiation. Adeno-associated virus-modified T cells were introduced into patient-derived orthotopic xenograft (PDOX) model to assess the combined impact of LTβR and glycolysis inhibitors on the Th17/Treg cell differentiation. We found that LTβR reduced PELI1 expression, preventing TRAF3 protein degradation in Th17 cells. TRAF3 then competed with RORC for SMURF1 binding, enhancing RORC stability and Th17 cell differentiation. LTβR also blocked PRDM1 expression, delaying Foxp3 transcription and Treg cell infiltration. Additionally, N-glycosylation supported the stability of LTβR by protecting it from ubiquitination. From a therapeutic perspective, glycolysis inhibitors helped LTβR balance the proportion of Th17/Treg cells in PDOX model to inhibit tumor growth. In conclusion, our findings indicated that LTβR N-glycosylation prevented RORC ubiquitination and Foxp3 transcription, raising the Th17/Treg cell ratio and hindering HCC progression.

Fast and Accurate Draft Genome Patching with GPatch

Recent advancements in sequencing technologies have yielded numerous long-read draft genomes, promising to enhance our understanding of genomic variation. However, draft genomes are typically highly fragmented, posing significant challenges for functional genomics. We introduce GPatch, a tool that constructs chromosome-scale pseudoassemblies from fragmented drafts using alignments to a reference genome. GPatch produces complete, accurate, gap-free assemblies preserving over 95% of nucleotides from draft genomes. We show that GPatch assemblies can be used as references for Hi-C data analysis, whereas draft assemblies cannot. Until complete genome assembly becomes routine, GPatch presents a necessary tool for maximizing the utility of draft genomes.

"Frustratingly easy" domain adaptation for cross-species transcription factor binding prediction

Motivation

Sequence-to-function models interpret genomic DNA and predict functional outputs, successfully characterizing regulatory sequence activity. However, interpreting these models remains challenging, raising questions about the generalizability of inferred sequence functions. Cross-species prediction of transcription factor (TF) binding offers a promising approach to enhance model generalization by leveraging sequence variation across species, and it can contribute to the discovery of a conserved gene-regulatory code. However, addressing systematic differences between the genomes of various species is a significant challenge.

Results

We introduce MORALE, a framework that utilizes a well-established domain adaptation approach that is "frustratingly easy." MORALE trains on sequences from one or more source species and predicts TF binding on a single target species where no binding data is available. To learn an invariant cross-species sequence representation, MORALE aligns the first and second moments of the datagenerating distribution between all species. This direct approach integrates easily into representation learning models with an embedding layer. Unlike alternatives such as adversarial learning, it does not require additional parameters or other model design choices. We apply MORALE to two ChIP-seq datasets of liver-essential TFs: one comprising human and mouse, and another comprising five mammalian species. Compared to both a baseline and an adversarial approach termed gradient reversal (GRL), MORALE demonstrates improved performance across all TFs in the two-species case. Importantly, it avoids a performance degradation observed with the GRL approach in this study. Furthermore, feature attribution revealed that important motifs discovered by MORALE were closer to the actual TF binding motif compared with the GRL approach. For the five-species case, our method significantly improved TF binding site prediction for all TFs when predicting on human data, surpassing the performance of a human-only model - a result not observed in the two-species comparison. Overall, MORALE is a direct and competitive approach that leverages domain adaptation techniques to improve cross-species TF binding site prediction.

Availability and implementation

All source code is available at https://github.com/loudrxiv/frustrating .

A Tandem Repeat Atlas for the Genome of Inbred Mouse Strains: A Genetic Variation Resource

Tandem repeats (TRs) are a significant source of genetic variation in the human population; and TR alleles are responsible for over 60 human genetic diseases and for inter-individual differences in many biomedical traits. Therefore, we utilized long-read sequencing and state of the art computational programs to produce a database with 2,528,854 TRs covering 39 inbred mouse strains. As in humans, murine TRs are abundant and were primarily located in intergenic regions. However, there were important species differences: murine TRs did not have the extensive number of repeat expansions like those associated with human repeat expansion diseases and they were not associated with transposable elements. We demonstrate by analysis of two biomedical phenotypes, which were identified over 40 years ago, that this TR database can enhance our ability to characterize the genetic basis for trait differences among the inbred strains.

Ero1a, the most strongly hypoxia-induced protein in PASMCs, promotes the development of hypoxia- and monocrotaline-induced pulmonary hypertension in rats

AIMS

Pulmonary hypertension (PH) is a progressive and life-threatening condition characterized by elevated pressure in the pulmonary circulation, leading to right heart dysfunction and ultimately heart failure. Pulmonary artery smooth muscle cells (PASMCs) are key players in group 3 PH (due to lung diseases and/or hypoxia) progression, where their aberrant proliferation and migration drive vascular remodeling. Dysregulated proteins in PASMCs are critical in PH development. Our research was designed to investigate the most promising potential therapeutic targets for PH.

MATERIALS AND METHODS

Proteomics was used to identify the most significantly upregulated protein in PASMCs under hypoxia. siRNA or plasmid transfection was used to silence or overexpress Ero1a. The proliferation, migration, and apoptosis of PASMCs were assessed respectively. Both hypoxia and monocrotaline-induced pulmonary hypertension model were established in animals. The expression of Ero1a was reduced to explore its role in PH. Bioinformatic analysis were conducted to investigate the signaling pathways involved in the disease progression.

KEY FINDINGS

Ero1a was confirmed as the most significantly upregulated protein in PASMCs under hypoxia. Silencing Ero1a reduced PASMC proliferation, migration, and apoptosis resistance under both normoxic and hypoxic conditions, while overexpression of Ero1a had the opposite effect. Exposure of rats to hypoxia, along with intraperitoneal injection of MCT solution, induced PH. However, knockdown of Ero1a alleviated all these pathological features. The HIF1-Ero1a-Apelin/APJ signaling axis was speculated to mediate the functional role of Ero1a in PH.

SIGNIFICANCE

Our study identifies that targeting Ero1a may represent a promising therapeutic strategy for pulmonary hypertension.

Ȧland Island eye disease in two patients harboring novel CACNA1F variants

Ȧland Island eye disease (ȦIED) is a rare X-linked recessive condition caused by mutations in the CACNA1F gene. The ȦIED phenotype involves an overlap of canonical features of ocular albinism and congenital stationary night blindness (CSNB), thereby presenting a diagnostic challenge. Genetic testing often cannot distinguish between ȦIED and CSNB, as many mutations in CACNA1F are known to cause either ȦIED, CSNB, or conditions with ambiguous phenotypes along the ȦIED/CSNB continuum. Therefore, it is necessary to expand the landscape of CACNA1F mutations responsible for this spectrum of conditions. We report two novel CACNA1F variants in patients with a clinical presentation of ȦIED, including low visual acuity, congenital nystagmus, high myopia, hypopigmented fundi, foveal hypoplasia, and choroidal thinning. Electroretinographic findings included decreased rod- and cone-mediated responses, electronegative mixed responses, as well as a novel finding of electronegative rod-mediated responses. While these patients' presentations are consistent with ȦIED, future studies will be needed to determine whether these novel CACNA1F variants are exclusive to ȦIED or can cause phenotypes along the entire ȦIED/CSNB2A spectrum.

Deciphering enhancers of hearing loss genes for efficient and targeted gene therapy of hereditary deafness

Hereditary hearing loss accounts for about 60% of congenital deafness. Although adeno-associated virus (AAV)-mediated gene therapy shows substantial potential for treating genetic hearing impairments, there remain significant concerns regarding the specificity and safety of AAV vectors. The sophisticated nature of the cochlea further complicates the challenge of precisely targeting gene delivery. Here, we introduced an AAV-reporter-based in vivo transcriptional enhancer reconstruction (ARBITER) workflow, enabling efficient and reliable dissection of enhancers. With ARBITER, we successfully demonstrated that the conserved non-coding elements (CNEs) within the gene locus collaboratively regulate the expression of Slc26a5, which was further validated using knockout mouse models. We also assessed the potential of identified enhancers to treat hereditary hearing loss by conducting gene therapy in Slc26a5 mutant mice. Based on the original Slc26a5 enhancer with limited efficiency, we engineered a highly efficient and outer hair cell (OHC)-specific enhancer, B8, which successfully restored hearing of Slc26a5 knockout mice.

Genome-wide analysis of genetic loci and candidate genes related to teat number traits in Dongliao black pigs

This study investigated the genetic basis of teat number variation in Dongliao black pigs. A total of 765 pigs were genotyped using the Porcine 50K SNP chip, and their teat numbers were recorded. Heritability estimates for total teat number (TTN) and teat pair number (TPN) were 0.091 and 0.097, respectively. Genome-wide association studies identified 74 significant SNPs for TTN and 105 for TPN. Nine candidate genes related to the teat number were identified: CSNK1G1, PLEKHM2, CABLES1, SLC25A21, RYR3, PIGH, GUCY1A1, RAPGEF2, and TRPC4AP. These findings provide insights into the genetic architecture of teat number variation in Dongliao black pigs.

Identification and Characterization of a Rare Exon 22 Duplication in CFTR in Two Families

Accurate genetic diagnosis is essential for appropriate treatment in cystic fibrosis (CF). Large copy number variants like duplications in the CFTR gene are rare and often classified as variants of uncertain significance (VUSs) due to unknown characteristics of the inserted material, complicating diagnosis and treatment decisions. We identified a previously uncharacterized exon 22 duplication (CFTRdup22) in the CFTR gene in two anamnestically unrelated people with CF, both exhibiting a mild phenotype. Initial classification as a VUS was based on standard genetic testing. We employed a custom next-generation sequencing (NGS) panel to determine the exact breakpoints of the duplication and conducted mRNA sequencing to confirm its effect on splicing. DNA and RNA analyses allowed for precise breakpoint determination, confirming that the duplication was in tandem and the reading frame remained intact. This, as well as a residual CFTRdup22 function of ~30% as measured via intestinal current measurement, is consistent with a clinically milder CF phenotype. Collectively, the precise characterization of the variants' breakpoints, localization and orientation enabled us to reclassify the variant as likely pathogenic. This study highlights the importance of advanced genetic techniques, such as NGS and breakpoint analysis, in accurately identifying CF-causing variants. It underscores the importance of a comprehensive approach and persistence when suspecting a specific genetic condition. This can aid in reclassifying VUSs, providing a definitive diagnosis for the affected family and enabling appropriate therapeutic interventions, including the use of CFTR modulators.

Dynamic interaction of MYC enhancer RNA with YEATS2 protein regulates MYC gene transcription in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the most prevalent and aggressive forms of pancreatic cancer with low survival rates and limited treatment options. Aberrant expression of the MYC oncogene promotes PDAC progression. Recent reports have established a role for enhancer RNAs (eRNAs), originating from active enhancers, in controlling gene transcription. Here we show that a novel MYC eRNA regulates MYC gene expression during chronic inflammatory conditions in pancreatic cancer cells. A higher amount of MYC eRNA is observed in chronic pancreatitis and in pancreatic cancer patients. We show that MYC eRNA interacts with YEATS2, a histone reader protein of the ATAC-HAT complex, and augments the association of YEATS2-containing ATAC complexes with MYC promoter/enhancer regions and thus increases MYC gene expression. TNF-α induced Tyrosine dephosphorylation of the YEATS domain increases MYC eRNA binding to the YEATS2 protein in pancreatic cancer cells. Our study adds another regulatory layer of MYC gene expression by enhancer-driven transcription.

Profiling of RBM20-Regulated CaMKIIδ Splice Variants Across the Heart, Skeletal Muscle, and Olfactory Bulbs

Calcium/calmodulin-dependent protein kinase IIδ (CaMKIIδ), encoded by the Camk2d gene, plays key regulatory roles in various Ca2+-regulated cellular processes. Extensive alternative splicing of the Camk2d gene generates multiple CaMKIIδ splice variants that exhibit differential roles. Despite significant advances in understanding the functions of CaMKIIδ, the full repertoire of Camk2d splice variants in a variety of tissues and their distinct roles in physiological and pathological contexts remain incompletely characterized due to the complex nature of multiple alternative splicing events. Here, we conducted long-read amplicon sequencing to investigate the murine Camk2d splice variants in the heart, skeletal muscle, and olfactory bulbs and show that mRNAs in the heart and skeletal muscle have shorter 3'UTRs. Our results in this study suggest that a key regulator of Camk2d splicing, RNA-binding motif protein 20 (RBM20), whose gain-of-function mutations cause dilated cardiomyopathy, is crucial for the expression of heart-specific splice variants. Olfactory bulbs specifically express novel splice variants that utilize a mutually exclusive exon 6B and/or an alternative polyadenylation site in a novel exon 17.5 in an RBM20-independent manner. The tissue-specific repertoire of CaMKIIδ splice variants and their aberrant expression in disease model animals will help in understanding their roles in physiological and pathological contexts.

Updates on Toll-Like Receptor 10 Research

Toll-like receptors (TLRs) are transmembrane proteins that share sequence similarity and biological function as they are responsible for the innate immune response to exogenous or endogenous molecular patterns. Distinct ligands are recognized by the leucine-rich repeats regions and trigger an inflammatory signal into the cell thanks to the TIR domain of TLR. TLR10 shares the same structural organization but shows a unique expression pattern and functional activity yet to be fully elucidated. In this review, we summarize the literature on TLR10 expression and cellular localization. Several polymorphisms were reported for the TLR10 gene that is present in most mammalians and arose from gene duplication of an ancestral TLR1-like gene. Accordingly, TLR10 was shown to act as TLR1 in terms of TLR2 interaction and TLR1/2 ligands recognition; however, in contrast to all the other TLRs it could also trigger anti-inflammatory signaling and was responsive to several unrelated microbial components. In this review, we will describe key steps and recent updates on TLR10 research highlighting common or divergent findings, in humans and animals.

Hotspot BRCA1/2 Mutations in Tumors With Microsatellite Instability Suggest Passenger Mutation Status and Evaluation of Therapeutic Options

PURPOSE

In cancers with both high microsatellite instability (MSI-H) and BRCA1/2 mutations, BRCA1/2 mutations may be incidentally caused by MSI and represent passenger mutations versus drivers of those cancers. Reporting of these mutations without additional clarification may result in poly (ADP-ribose) polymerase (PARP) inhibitor therapy, where there is not likely true benefit. The purpose of this work was to identify BRCA1/2 passenger mutation hotspots that are secondary to MSI-H status rather than truly independent driving mutations.

METHODS

We analyzed over 100,000 pancancer patient cases in cBioPortal with both BRCA1/2 mutations and MSI-H status to identify passenger mutation hotspots that recur in microsatellite sites. We validated these hotspots as likely reflective of MSI-H status using a data set of nearly 20,000 patient cases from the University of Washington.

RESULTS

We identified six recurrent frameshift passenger mutation hotspots in BRCA1 (K339fs and K654fs) and BRCA2 (I605fs, W1692fs, N1784fs, and T3033fs). These hotspots represented 17% and 21% of all truncating BRCA1/2 mutations detected in the cBioPortal and University of Washington data sets, respectively, and were seen almost exclusively in MSI-H tumors. These hotspots had a mean variant allele fraction of 17%, supporting their occurrence as passenger mutations. All hotspots are annotated in ClinVar as pathogenic variants, and all but one in catalogue of somatic mutations in cancer as somatic hotspots. Current annotations do not mention MSI.

CONCLUSION

Our findings emphasize the need for molecular pathology laboratories and clinical variant databases to annotate BRCA1/2 passenger mutation hotspots with more context to interpret their pathogenicity in the setting of concurrent MSI. Identification and annotation of such hotspots will improve how oncology providers guide patients regarding therapeutic options.

A Blueprint for Translational Precision Medicine in Autism Spectrum Disorder and Related Neurogenetic Syndromes

Objectives: Despite growing knowledge of the underlying neurobiology of autism spectrum disorder (ASD) and related neurogenetic syndromes, treatment discovery has remained elusive. In this review, we provide a blueprint for translational precision medicine in ASD and related neurogenetic syndromes. Methods: The discovery of trofinetide for Rett syndrome (RTT) is described, and the role of nonmammalian, mammalian, and stem cell model systems in the identification of molecular targets and drug screening is discussed. We then provide a framework for translating preclinical findings to human clinical trials, including the role of biomarkers in selecting molecular targets and evaluating target engagement, and discuss how to leverage these findings for future ASD drug development. Results: Multiple preclinical model systems for ASD have been developed, each with tradeoffs with regard to suitability for high-throughput small molecule screening, conservation across species, and behavioral face validity. Future clinical trials should incorporate biomarkers and intermediate phenotypes to demonstrate target engagement. Factors that contributed to the approval of trofinetide for RTT included replicated findings in mouse models, a well-studied natural history of the syndrome, development of RTT-specific outcome measures, and strong engagement of the RTT family community. Conclusions: The translation of our growing understanding of the neurobiology of ASD to human drug discovery will require a precision medicine approach, including the use of multiple model systems for molecular target selection, evaluation of target engagement, and clinical trial design strategies that address heterogeneity, power, and the placebo response.

CREPE (CREate Primers and Evaluate): a computational tool for large-scale primer design and specificity analysis

Polymerase chain reaction (PCR) is ubiquitous in biological research labs, as it is a fast, flexible, and cost-effective technique to amplify a DNA region of interest. However, manual primer design can be an error-prone and time-consuming process depending on the number and composition of target sites. While Primer3 has emerged as an accessible tool to solve some of these issues, additional computational pipelines are required for appropriate scaling. Moreover, this does not replace the manual confirmation of primer specificity (i.e., the assessment of off-targets). To overcome the challenges of large-scale primer design, we fused the functionality of Primer3 and In-Silico PCR (ISPCR); this integrated pipeline, CREPE ( CRE ate P rimers and E valuate), performs primer design and specificity analysis through a custom evaluation script for any given number of target sites at scale. Its final output summarizes the lead forward and reverse primer pair for each target site, a measure of the likelihood of binding to off-targets, and additional information to aid decision-making. We provide this through a customized workflow for targeted amplicon sequencing (TAS) on a 150bp paired-end Illumina platform. Experimental testing showed successful amplification for more than 90% of primers deemed acceptable by CREPE.

An ancient regulatory variant of ACSF3 influences the coevolution of increased human height and basal metabolic rate via metabolic homeostasis

Anatomically modern humans (AMHs) exhibit a significant increase in basal metabolic rate (BMR) and height compared to non-human apes. This study investigates the genetic basis underlying these traits. Our analyses reveal a strong genetic correlation between height and BMR. A regulatory mutation, rs34590044-A, was found to be associated with the increased height and BMR in AMHs. rs34590044-A upregulates the expression of ACSF3 by increasing its enhancer activity, leading to increased body length and BMR in mice fed essential amino acids which are characteristic of meat-based diets. In the British population, rs34590044-A has been under positive selection over the past 20,000 years, with a particularly strong signal in the last 5,000 years, as also evidenced by ancient DNA analysis. These results suggest that the emergence of rs34590044-A may have facilitated the adaptation to a meat-enriched diet in AMHs, with increased height and BMR as consequences of this dietary shift.

Identification of USP39 as a prognostic and predictive biomarker for determining the response to immunotherapy in pancreatic cancer

Ubiquitin-Specific Protease 39 (USP39) has been implicated in numerous malignancies, however, its pathogenic mechanisms and impact on the tumor immune microenvironment (TIME) remain incompletely characterized. Based on The Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) databases, we investigated the diagnostic and prognostic values of USP39 across various cancer types. Additionally, we examined the correlation between USP39 expression and immune-related gene signature, immune cell infiltration pattern, tumor microsatellite instability (MSI), and tumor mutation burden (TMB). This study specifically focused on exploring the clinical relevance and molecular functions of USP39 in pancreatic adenocarcinoma (PAAD), with particularly emphasis on its role in shaping the TIME and modulating responses to immunotherapy. The results demonstrated that evaluated USP39 expression significantly correlated with advanced tumor stage and unfavorable clinical outcomes across multiple cancer types, most notably in PAAD. Functional enrichment analysis indicated that USP39 potentially promotes tumor progression through multiple oncogenic signaling cascades. In vitro experimental validation confirmed that USP39 knockdown inhibited migration and proliferation of pancreatic cancer cells while inducing apoptosis. Additionally, we identified significant positive correlations between USP39 expression and immune checkpoint molecules, particularly prominent in PAAD. Furthermore, we observed associations between USP39 expression and TMB in 16 cancer types and MSI in 11 cancer types, suggesting that heightened USP39 expression may enhance responsiveness to immunotherapeutic interventions. Collectively, our findings establish USP39 as a valuable immune-related biomarker with both diagnostic and prognostic utility across multiple cancer types, especially PAAD, underscoring its potential as a promising therapeutic target for cancer immunotherapy. Clinical trial number Not applicable.

Perfluorooctane sulfonic acid: a possible risk factor of endothelial dysfunction based on in silico and in vitro studies

Perfluorooctane sulfonic acid (PFOS) is a fluorinated chemical utilized in a variety of industrial and household products. PFOS has been detected in human serum and is associated with multiple human adverse health effects. Epidemiological evidence has linked PFOS exposure to endothelial dysfunction, which is a key contributor to atherosclerosis. However, the underlying mechanisms of PFOS-induced endothelial dysfunction associated atherosclerosis has not been investigated. In the present study, human microvascular endothelial cells (HMEC-1) exposed to PFOS (15 μM) for 72 h, mimicking long-term exposure. We further employed integrated RNA-sequencing (RNA-seq) and transcriptomic analysis to identify differentially expressed genes (DEGs) for biological alterations: gene ontology (GO), pathway enrichment analysis (KEGG), protein-protein interaction network and modular clustering analysis. Furthermore, the Metascape database was used for disease association, tissue specificity, and transcription factor analysis. Hub genes were verified using atherosclerosis patient data sets from the GEO dataset. Alteration of hub genes in patients was then validated using immunoblotting and ELISA. Our results revealed that PFOS altered amino acid biosynthesis, lipid metabolism and induced the ER-stress response through the HRI/eIF2α/ATF4 pathway, leading to endothelial dysfunction. Interestingly, we found that PFOS induced inflammation by increasing COX-2, ICAM-1 and IL-6 expression through NF-κB and JAK2/STAT3 pathway in endothelial cells. Moreover, up-regulated C/EBPβ and ATF4 were observed in both patients and PFOS-exposed endothelium, which may use as an early biomarker and may have a potential role in PFOS-induced endothelial dysfunction. These findings provide novel insight into the underlying molecular mechanisms of PFOS-induced endothelial dysfunction associated with atherosclerosis.

A Pangenomic Approach to Improve Population Genetics Analysis and Reference Bias in Underrepresented Middle Eastern and Horn of Africa Populations

Genomics plays a crucial role in addressing health disparities, yet most studies rely on the hg38 linear reference genome, limiting the potential of pangenomic approaches, particularly for underrepresented populations. In this study, we focus on characterising East African populations, particularly Somalis, by constructing a variation graph using Mozabites from the Human Genome Diversity Project (HGDP) given their ancestral affinity with Somalis. We evaluated the effectiveness of this graph-based reference in estimating effective population sizes (Ne) in Bedouins compared to the hg38 reference and examined its impact on allele frequencies and genome-wide association studies (GWAS). Applying a coalescent model to the graph-based reference produced a Ne estimate of approximately 17 for the Bedouin population, which was significantly lower than the estimate from the hg38 reference (approximately 79,000). Only the graph-based estimate fell within the 95% confidence interval in simulations, indicating improved accuracy. Moreover, graph variants exhibited significantly lower allele frequencies (p-value < 2.2 × 10-16), suggesting potential effects on the interpretation and power of GWAS. Notably, GWAS variants specific to Bedouins derived from the graph showed lower frequencies (p = 0.023) than those obtained from the linear reference. These findings suggest that a pangenomic approach, informed by populations with ancestral affinities such as the Mozabites, provides more accurate estimates of Ne and allele frequencies. This highlights the importance of pangenomic strategies to better capture genetic diversity in underrepresented populations, a critical step towards improving population genetics studies, personalised medicine, and equitable healthcare.

Non-canonical DNA in human and other ape telomere-to-telomere genomes

Non-canonical (non-B) DNA structures-e.g. bent DNA, hairpins, G-quadruplexes (G4s), Z-DNA, etc.-which form at certain sequence motifs (e.g. A-phased repeats, inverted repeats, etc.), have emerged as important regulators of cellular processes and drivers of genome evolution. Yet, they have been understudied due to their repetitive nature and potentially inaccurate sequences generated with short-read technologies. Here we comprehensively characterize such motifs in the long-read telomere-to-telomere (T2T) genomes of human, bonobo, chimpanzee, gorilla, Bornean orangutan, Sumatran orangutan, and siamang. Non-B DNA motifs are enriched at the genomic regions added to T2T assemblies and occupy 9%-15%, 9%-11%, and 12%-38% of autosomes and chromosomes X and Y, respectively. G4s and Z-DNA are enriched at promoters and enhancers, as well as at origins of replication. Repetitive sequences harbor more non-B DNA motifs than non-repetitive sequences, especially in the short arms of acrocentric chromosomes. Most centromeres and/or their flanking regions are enriched in at least one non-B DNA motif type, consistent with a potential role of non-B structures in determining centromeres. Our results highlight the uneven distribution of predicted non-B DNA structures across ape genomes and suggest their novel functions in previously inaccessible genomic regions.

Protocol for assembling, prioritizing, and characterizing piRNA clusters using the piRNA Cluster Builder

PIWI-interacting RNAs (piRNAs) play a critical role in safeguarding genome integrity in germ cells, ensuring fertility. Here, we provide a protocol for processing piRNA sequencing data, identifying piRNA-rich genomic regions as piRNA clusters, and preparing these clusters for downstream analyses. We describe steps for assembling piRNA cluster regions using an R-based tool, the piRNA Cluster Builder (PICB), which integrates unique and multimapping piRNA reads stepwise. The protocol allows for parameter optimizations and generates normalized outputs for prioritization of piRNA clusters. For complete details on the use and execution of this protocol, please refer to Konstantinidou et al.1.

NAD + Sensing by PARP7 Regulates the C/EBPβ-Dependent Transcription Program in Adipose Tissue In Vivo

We have identified PARP7, an NAD + -dependent mono(ADP-ribosyl) transferase, as a key regulator of the C/EBPβ-dependent proadipogenic transcription program. Moreover, PARP7 is required for efficient adipogenesis and downstream biological functions, including involution of the lactating mammary gland. PARP7 serves as a coregulator of C/EBPβ, and depletion of PARP7 causes a dramatic reduction in C/EBPβ binding across the genome. PARP7 functions as a sensor of nuclear NAD + levels to control gene expression. At the relatively high nuclear NAD + concentrations in undifferentiated preadipocytes, PARP7 is catalytically active for auto- mono(ADP-ribosyl)ation (autoMARylation). As nuclear NAD + concentrations decline post- differentiation, autoMARylation decreases dramatically. AutoMARylation promotes instability of PARP7 through an E3 ligase-ubiquitin-proteasome pathway mediated by the ADP-ribose (ADPR)-binding ubiquitin E3 ligases DTX2 and RNF114. Genetic depletion of PARP7 in mice promotes a dramatic reduction in a wide array of lipids in the mammary gland fat pads and milk from lactating females, as well as a significant decrease in nicotinamide mononucleotide (NMN), a key nutrient in mother's milk. The latter is due to reduced expression of Nampt , the gene encoding NAMPT, the enzyme that produces NMN, which is a direct transcriptional target of PARP7 and C/EBPβ. Collectively, our results extend the biology of PARP7 to adipogenesis and perinatal health. Moreover, our results describe the molecular events that regulate these downstream biological functions.

Non-coding single-nucleotide and structural variants affecting the EYS putative promoter cause autosomal recessive retinitis pigmentosa

PURPOSE

Variants in untranslated genomic regions are difficult to identify as pathogenic but are capable of causing disease by interfering with gene expression. This study aimed to characterize the effect of variants identified in the 5'-untranslated region of EYS in patients with autosomal recessive retinitis pigmentosa (RP).

METHODS

Variant screening included gene panels, Sanger, exome, and genome sequencing. Functional validation included an electrophoretic mobility shift assay and various luciferase assays.

RESULTS

Patients with RP from 6 EYS biallelic Arab-Muslim families harbored a 5' noncoding EYS variant, c.-453G>T, and 4 harbored a structural variant affecting the 5' noncoding exons. Electrophoretic mobility shift assay analysis revealed an effect on binding of transcription factors for c.-453G>T and a neighboring variant c.-454G>T. Dual luciferase assays using overexpression of various transcription factors showed distinct effects on expression. c.-453G>T was associated with higher luciferase expression with CRX overexpression and c.-454G>C with OTX2 overexpression. In addition, the 2 variants were found to influence translation by affecting upstream initiation codons. Interestingly, visual function of EYS RP patients who harbor c.-453G>T are better than those with biallelic null EYS variants.

CONCLUSION

Our analysis revealed both single-nucleotide and structural variants in the EYS promoter as the cause of autosomal recessive RP. These variants may affect EYS expression via a dual mechanism by altering transcription factor binding affinity at the EYS promoter and by affecting upstream open reading frames.

Expression spectrum of TE-derived transcripts in human adult tissues

Transposable elements (TEs) are vital components of eukaryotic genomes and have played a critical role in genome evolution. Although most TEs are silenced in the mammalian genome, increasing evidence suggests that certain TEs are actively involved in gene regulation during early developmental stages. However, the extent to which human TEs drive gene transcription in adult tissues remains largely unexplored. In this study, we systematically analyzed 17,329 human transcriptomes to investigate how TEs influence gene transcription across 47 adult tissues. Our findings reveal that TE-derived transcripts are broadly expressed in human tissues, contributing to both housekeeping functions and tissue-specific gene regulation. We identified sex-specific expression of TE-derived transcripts regulated by sex hormones in breast tissue between females and males. Our results demonstrated that TE-derived alternative transcription initiation significantly enhances the variety of translated protein products, e.g., changes in the N-terminal peptide length of WNT2B caused by TE-derived transcription result in isoform-specific subcellular localization. Additionally, we identified 68 human-specific TE-derived transcripts associated with metabolic processes and environmental adaptation. Together, these findings highlight the pivotal evolutionary role of TEs in shaping the human transcriptome, demonstrating how conserved and human-specific TEs contribute to transcriptional and translational innovation in human genome evolution.

Comprehensive Atomic-Scale 3D Viral-Host Protein Interactomes Enable Dissection of Key Mechanisms and Evolutionary Processes Underlying Viral Pathogenesis

Viral-human protein interactions are critical for viral replication and modulation of the host immune response. Structural modeling of these interactions is vital for developing effective antiviral therapies and vaccines. However, 99% of experimentally determined binary host-viral interactions currently lack structural information. We aimed to address this gap by leveraging computational protein structure prediction methods. Using extensive benchmarking, we found AlphaFold to be the most accurate structure prediction model for host-pathogen protein interactions. We then predicted the structures of 11,666 binary protein interactions across 33 viral families and created the most comprehensive atomic-scale 3D viral-host protein interactomes till date ( https://3d-viralhuman.yulab.org ). By integrating these interactomes with genetic variation data, we identified population-specific signatures of selection on variants coding for interfaces of viral-human interactions. We also found that viral interaction interfaces were less conserved than non-interface regions, a striking trend that is opposite to what is observed for host interfaces, suggesting different evolutionary pressures. Systematic analyses of interface sharing between host and viral proteins binding to the same host protein revealed mutation rate-dependent differences in interface mimicry. Similar mutation rate-dependent differences were seen in the interface sharing between viral proteins binding to a host protein. We also found that the patterns of E6 protein binding to KPNA2 differed between high- and low-risk oncogenic human papillomaviruses (HPVs), and clustering based on these binding patterns allowed the classification of HPVs with unknown oncogenic risk. Our interface mimicry analyses also unveiled a novel mechanism by which herpes simplex virus-1 UL37 suppresses the antiviral immune response through disruption of the TRAF6-MAVS signalosome interaction. Overall, our comprehensive 3D viral interactomes provide a resource at unprecedented scale and resolution that will enable researchers to explore how variation and signatures of selection influence viral interactions and disease progression. This tool also facilitates the identification of conserved and unique interaction patterns across viruses, empowering researchers to generate testable hypotheses and ultimately accelerate the discovery of novel therapeutic targets and intervention strategies.

Human Body Single-Cell Atlas of 3D Genome Organization and DNA Methylation

Higher-order chromatin structure and DNA methylation are critical for gene regulation, but how these vary across the human body remains unclear. We performed multi-omic profiling of 3D genome structure and DNA methylation for 86,689 single nuclei across 16 human tissues, identifying 35 major and 206 cell subtypes. We revealed extensive changes in CG and non-CG methylation across almost all cell types and characterized 3D chromatin structure at an unprecedented cellular resolution. Intriguingly, extensive discrepancies exist between cell types delineated by DNA methylation and genome structure, indicating that the role of distinct epigenomic features in maintaining cell identity may vary by lineage. This study expands our understanding of the diversity of DNA methylation and chromatin structure and offers an extensive reference for exploring gene regulation in human health and disease.

Arteriovenous malformation from a patient with JP-HHT harbours two second-hit somatic DNA alterations in SMAD4

BACKGROUND

Hereditary haemorrhagic telangiectasia (HHT) is an inherited disorder of vascular malformations. It is caused by inherited loss-of-function mutations in one of three genes, ENG, ACVRL1 or SMAD4. We recently showed that HHT-associated vascular malformations from liver, lung, brain and skin develop via a two-hit genetic mechanism resulting from biallelic loss-of-function mutations in either ENG or ACVRL1. Second-hit somatic mutations in SMAD4 have not been reported in HHT-associated vascular malformations. Here, we investigate a large, aggressively growing craniofacial arteriovenous malformation (AVM) from an individual with juvenile polyposis-HHT caused by a germline mutation in SMAD4.

METHODS

We sequenced DNA from the AVM using a targeted gene sequencing panel to at least 1000X to identify somatic mutations that might contribute to the development of the AVM. We analysed whole genome SNP genotyping data using the algorithm Mosaic Chromosomal Alterations (MoChA) to identify somatic loss of heterozygosity.

RESULTS

We confirmed the germline mutation in SMAD4 (c.1610A>T, p.Asp537Val) and identified a second-hit somatic mutation also in SMAD4 (c.350dup, p.Tyr117*) that occurred in trans relative to the germline mutation. We also identified somatic loss of heterozygosity on the q arm of chromosome 18, including SMAD4. Additionally, we confirmed that the loss of heterozygosity causes loss of the wild-type allele. Thus, we identified two independent somatic alterations in SMAD4 causing biallelic loss of SMAD4 function in the AVM tissue.

CONCLUSION

We identified biallelic loss of function of SMAD4 in a craniofacial AVM, evidence that SMAD4 also follows the two-hit mutation mechanism of HHT-associated vascular malformation pathogenesis.

Self-organization of mouse embryonic stem cells into reproducible pre-gastrulation embryo models via CRISPRa programming

Embryonic stem cells (ESCs) can self-organize into structures with spatial and molecular similarities to natural embryos. During development, embryonic and extraembryonic cells differentiate through activation of endogenous regulatory elements while co-developing via cell-cell interactions. However, engineering regulatory elements to self-organize ESCs into embryo models remains underexplored. Here, we demonstrate that CRISPR activation (CRISPRa) of two regulatory elements near Gata6 and Cdx2 generates embryonic patterns resembling pre-gastrulation mouse embryos. Live single-cell imaging revealed that self-patterning occurs through orchestrated collective movement driven by cell-intrinsic fate induction. In 3D, CRISPRa-programmed embryo models (CPEMs) exhibit morphological and transcriptomic similarity to pre-gastrulation mouse embryos. CPEMs allow versatile perturbations, including dual Cdx2-Elf5 activation to enhance trophoblast differentiation and lineage-specific activation of laminin and matrix metalloproteinases, uncovering their roles in basement membrane remodeling and embryo model morphology. Our findings demonstrate that minimal intrinsic epigenome editing can self-organize ESCs into programmable pre-gastrulation embryo models with robust lineage-specific perturbation capabilities.

A Bivalent Molecular Glue Linking Lysine Acetyltransferases to Oncogene-induced Cell Death

Developing cancer therapies that induce robust death of the malignant cell is critical to prevent relapse. Highly effective strategies, such as immunotherapy, exemplify this observation. Here we provide the structural and molecular underpinnings for an approach that leverages chemical induced proximity to produce specific cell killing of diffuse large B cell lymphoma, the most common non-Hodgkin's lymphoma. We develop KAT-TCIPs (lysine acetyltransferase transcriptional/epigenetic chemical inducers of proximity) that redirect p300 and CBP to activate programmed cell death genes normally repressed by the oncogenic driver, BCL6. Acute treatment rapidly reprograms the epigenome to initiate apoptosis and repress c-MYC. The crystal structure of the chemically induced p300-BCL6 complex reveals how chance interactions between the two proteins can be systematically exploited to produce the exquisite potency and selectivity of KAT-TCIPs. Thus, the malignant function of an oncogenic driver can be co-opted to activate robust cell death, with implications for precision epigenetic therapies.

Comparing the predictors of mutability among healthy human tissues inferred from mutations in single-cell genome data

Studying mutation in healthy somatic tissues is the key for understanding the genesis of cancer and other genetic diseases. Mutation rate varies from site to site in the human genome by up to 100-fold and is influenced by numerous epigenetic and genetic factors including GC content, trinucleotide sequence context, and DNAse accessibility. These factors influence mutation at both local and regional scales and are often interrelated with one another, meaning that predicting mutability or uncovering its drivers requires modelling multiple factors and scales simultaneously. Historically, most investigations have focused either on analyzing the local sequence scale through triplet signatures or on examining the impact of epigenetic processes at larger scales, but not both concurrently. Additionally, sequencing technology limitations have restricted analyses of healthy mutations to coding regions (RNA-seq) or to those that have been influenced by selection (e.g. bulk samples from cancer tissue). Here, we leverage single-cell mutations and present a comprehensive analysis of epigenetic and genetic factors at multiple scales in the germline and 3 healthy somatic tissues. We create models that predict mutability with on average 2% error and find up to 63-fold variation among sites within the same tissue. We observe varying degrees of similarity between tissues: the mutability of genomic positions was 93.4% similar between liver and germline tissues, but sites in germline and skin were only 85.9% similar. We observe both universal and tissue-specific mutagenic processes in healthy tissues, with implications for understanding the maintenance of germline vs soma and the mechanisms underlying early tumorigenesis.

Genetic diversity and regulatory features of human-specific NOTCH2NL duplications

NOTCH2NL (NOTCH2-N-terminus-like) genes arose from incomplete, recent chromosome 1 segmental duplications implicated in human brain cortical expansion. Genetic characterization of these loci and their regulation is complicated by the fact they are embedded in large, nearly identical duplications that predispose to recurrent microdeletion syndromes. Using nearly complete long-read assemblies generated from 67 human and 12 ape haploid genomes, we show independent recurrent duplication among apes with functional copies emerging in humans ~2.1 million years ago. We distinguish NOTCH2NL paralogs present in every human haplotype (NOTCH2NLA) from copy number variable ones. We also characterize large-scale structural variation, including gene conversion, for 28% of haplotypes leading to a previously undescribed paralog, NOTCH2tv. Finally, we apply Fiber-seq and long-read transcript sequencing to human cortical neurospheres to characterize the regulatory landscape and find that the most fixed paralogs, NOTCH2 and NOTCH2NLA, harbor the greatest number of paralog-specific elements potentially driving their regulation.

Multiomic QTL mapping reveals phenotypic complexity of GWAS loci and prioritizes putative causal variants

Most GWAS loci are presumed to affect gene regulation; however, only ∼43% colocalize with expression quantitative trait loci (eQTLs). To address this colocalization gap, we map eQTLs, chromatin accessibility QTLs (caQTLs), and histone acetylation QTLs (haQTLs) using molecular samples from three early developmental-like tissues. Through colocalization, we annotate 10.4% (n = 540) of GWAS loci in 15 traits by QTL phenotype, temporal specificity, and complexity. We show that integration of chromatin QTLs results in a 2.3-fold higher annotation rate of GWAS loci because they capture distal GWAS loci missed by eQTLs, and that 5.4% (n = 13) of GWAS colocalizing eQTLs are early developmental specific. Finally, we utilize the iPSCORE multiomic QTLs to prioritize putative causal variants overlapping transcription factor motifs to elucidate the potential genetic underpinnings of 296 GWAS-QTL colocalizations.

Post translational modification regulation of transcription factors governing pancreatic β-cell identity and functional mass

Dysfunction of the insulin-secreting β-cells is a key hallmark of Type 2 diabetes (T2D). In the natural history of the progression of T2D, factors such as genetics, early life exposures, lifestyle, and obesity dictate an individual's susceptibility risk to disease. Obesity is associated with insulin resistance and increased demand for insulin to maintain glucose homeostasis. Studies in both mouse and human islets have implicated the β-cell's ability to compensate through proliferation and survival (increasing functional β-cell mass) as a tipping point toward the development of disease. A growing body of evidence suggests the reduction of β-cell mass in T2D is driven majorly by loss of β-cell identity, rather than by apoptosis alone. The development and maintenance of pancreatic β-cell identity, function, and adaptation to stress is governed, in part, by the spatiotemporal expression of transcription factors (TFs), whose activity is regulated by signal-dependent post-translational modifications (PTM). In this review, we examine the role of these TFs in the developing pancreas and in the mature β-cell. We discuss functional implications of post-translational modifications on these transcription factors' activities and how an understanding of the pathways they regulate can inform therapies to promoteβ-cell regeneration, proliferation, and survival in diabetes.

Inherited burden for disease predisposition in diverse populations

Background

Inherited burden for disease predisposition in diverse populations is an open question. American College of Medical Genetics and Genomics (ACMG) guidelines for variant classification, combined with large population variation databases, promise to provide valuable answers. We recently developed a robust ACMG-based automated variant classification tool and categorized the exome sequencing variants of 730,947 individuals from gnomAD.

Methods

We leveraged the allele frequency information of variants in 3895 Genomics England PanelApp genes and identified 76,677 pathogenic (P) and 295,356 likely-pathogenic (LP) variants, expanding the ClinVar submissions nearly fivefold.

Results

We found that, on average, an individual is born with 4.31 P or LP variants, of which 1.59 are compatible with a Mendelian condition, 1 in 12 presents with an actionable genotype, and a total of 372 genes are candidates for carrier screening. Furthermore, a genome-first approach revealed that the likelihood of having a genotype compatible with a disease is highest for congenital (1 in 2.24 individuals; 3.37 billion worldwide) followed by nervous (1 in 3.01; 2.39 billion), blood/immune (1 in 3.29; 2.04 billion), musculoskeletal/connective (1 in 3.65; 1.87 billion), skin (1 in 4.46; 1.62 billion), endocrine/metabolic (1 in 4.53; 1.62 billion), circulatory (1 in 7.26; 994 million), eye (1 in 7.62; 961 million), ear (1 in 8.39; 880 million), genitourinary (1 in 10.15; 750 million), neoplasm (1 in 16.01; 410 million), digestive (1 in 18.26; 312 million) and respiratory (1 in 47.72; 155 million) disorders.

Conclusions

Evidence-based genetic epidemiology demonstrates the potential of personalized medicine for the implementation of early preventive measures and incentivization of lifestyle changes to enhance healthspan and lifespan. From a societal standpoint, this research demonstrates the importance of informing the public to decrease discrimination and social stigmatization associated with inherited diseases, as an overwhelming majority of individuals are expected to carry germ-line risk variants on average.

Sp100A isoform promotes HIRA histone chaperone localization to PML nuclear bodies

PML nuclear bodies (PML-NBs) are dynamic subnuclear structures important for chromatin dynamics and anti-viral defense. In this study we investigate the role of Sp100 isoforms in promoting localization of the H3.3 histone chaperone HIRA to PML-NBs in human keratinocytes. Sp100 knockout (KO) cell lines were generated using CRISPR-Cas9 technology and shown to display normal keratinocyte differentiation and PML-NB formation. However, HIRA and its associated complex members (UBN1 and ASF1a) failed to localize to PML-NBs in the absence of Sp100, even after interferon stimulation. Exogenous expression of the four main isoforms of Sp100 showed that the Sp100A isoform is the primary driver of HIRA localization to PML-NBs, with the SUMO interacting motif (SIM) playing an important role. These findings highlight the functional diversity of the Sp100 isoforms in modulating chromatin dynamics at PML-NBs.

Rational design of a Lfng-enhancer AAV construct drives specific and efficient gene expression in inner ear supporting cells

Achieving cell-specific gene expression is crucial in the design of safe and efficacious gene therapies for the treatment of sensorineural hearing loss. Although a variety of adeno-associated virus (AAV) serotypes have been used to deliver genes to inner ear hair cells, few serotypes currently allow specific targeting of supporting cells. We sought to specifically target supporting cells by combining an AAV serotype with high tropism for the inner ear with enhancer sequences from the supporting cell-specific gene Lunatic Fringe (Lfng). We identified three candidate Lfng enhancer sequences using bioinformatic analysis to identify accessible chromatin and histone marks associated with active transcription of the Lfng locus in supporting cells. Candidate Lfng enhancers or the ubiquitous CBh promoter driving an EGFP reporter gene were packaged into the AAV-ie capsid, and the virus was introduced into the inner ear of neonatal mice. AAV-CBh-EGFP transduced multiple sensory and non-sensory inner ear cell types, as well as cells in the brain. One of the three Lfng enhancers gave robust EGFP expression in border cells, inner phalangeal cells, pillar cells, and all three rows of Deiters' cells along the entire cochlear duct, as well as in vestibular organ supporting cells. Significantly, no fluorescently labeled cells were detected in the brains of mice injected with this virus. We further designed an AAV-Lfng-CreERT2 vector that drove strong recombination in Cre reporter mice supporting cells after tamoxifen treatment. Our results provide a tool to specifically target supporting cells of the juvenile and adult inner ear.

Therapeutic Potential of STE20-Type Kinase STK25 Inhibition for the Prevention and Treatment of Metabolically Induced Hepatocellular Carcinoma

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is a rapidly growing malignancy with high mortality. Recently, metabolic dysfunction-associated steatohepatitis (MASH) has emerged as a major HCC catalyst; however, signals driving transition of MASH to HCC remain elusive and treatment options are limited. Herein, we investigated the role of STE20-type kinase STK25, a critical regulator of hepatocellular lipotoxic milieu and MASH susceptibility, in the initiation and progression of MASH-related HCC.

METHODS

The clinical relevance of STK25 in HCC was assessed in publicly available datasets and by RT-qPCR and proximity ligation assay in a validation cohort. The functional significance of STK25 silencing in human hepatoma cells was evaluated in vitro and in a subcutaneous xenograft mouse model. The therapeutic potential of STK25 antagonism was examined in a mouse model of MASH-driven HCC, induced by a single diethylnitrosamine injection combined with a high-fat diet.

RESULTS

Analysis of public databases and in-house cohorts revealed that STK25 expression in human liver biopsies positively correlated with HCC incidence and severity. The in vitro silencing of STK25 in human hepatoma cells suppressed proliferation, migration, and invasion with efficacy comparable to that achieved by anti-HCC drugs sorafenib or regorafenib. STK25 knockout in human hepatoma cells also blocked tumor formation and growth in a subcutaneous xenograft mouse model. Furthermore, pharmacologic inhibition of STK25 with antisense oligonucleotides-administered systemically or hepatocyte-specifically-efficiently mitigated the development and exacerbation of hepatocarcinogenesis in a mouse model of MASH-driven HCC.

CONCLUSION

This study underscores STK25 antagonism as a promising therapeutic strategy for the prevention and treatment of HCC in the context of MASH.