13384 results for ""pdc"+"heritage+language"+census+study"

in 22.65 milliseconds.

• Genomic Copy-Number Variants Drive Apoptotic Resistance and Relapses on Immune Checkpoint Inhibitors

  We investigated the genomic mechanisms underlying acquired resistance (AR) to immune checkpoint inhibitors (ICIs) across tumor types, specifically by examining how copy number variant (CNV)-driven subclonal evolution contributes to clinical relapses in melanoma patients. We analyzed longitudinal clinical melanoma samples from patients who experienced relapses on ICI therapy, complemented by isogenic human melanoma cell line models (M486) and murine melanoma tumor systems. Single-cell whole-genome sequencing (scWGS) was employed to resolve subclonal CNV patterns in AR tumors. The scWGS data revealed that AR-dominant subclones systematically deleted pro-apoptotic genes while amplifying anti-apoptotic genes and innate resistance pathway components. Notably, shared and private AR subclonal CNVs preexisted selective pressure, with convergent evolution targeting apoptosis-regulatory pathways and resulting in downregulated apoptotic/mitochondrial priming that enables ICI resistance. scWGS datasets from isogenic human melanoma cell lines, patient-matched tumor samples, and murine melanoma models will be made available through dbGaP, enabling researchers to access high-resolution subclonal CNV profiles that define the genomic landscape of acquired ICI resistance evolution.

  Study phs004102

• Non-invasive human skin transcriptome analysis using mRNA in skin surface lipids

  Non-invasive acquisition of mRNA data from the skin can be extremely useful for understanding skin physiology and diseases. Inspired by the holocrine process, in which the sebaceous glands secrete cell contents into the sebum, we focused on the possible presence of mRNAs in skin surface lipids (SSLs). We found that measurable levels of human mRNAs exist in SSLs, where the sebum protects them from degradation by RNases. The AmpliSeq transcriptome analysis was modified to measure SSL-RNA levels, and our results revealed that the SSL-RNAs predominantly comprised mRNAs derived from sebaceous glands, the epidermis, and hair follicles. Analysis of SSL-RNAs non-invasively collected from patients with atopic dermatitis revealed significantly increased expression of inflammation-related genes and decreased expression of terminal-differentiation���related genes, consistent with the results of previous reports. Further, we found that lipid-synthesis���related genes were downregulated in the sebaceous glands of patients with atopic dermatitis. These results indicate that the analysis of SSL-RNAs is a promising strategy to understand the pathophysiology of skin diseases.

  Study JGAS000416

• Ten colorectal cancer patients with locally advanced primary tumors who underwent primary tumor resection following neoadjuvant chemotherapy (NAC).

  Background We aim to investigate the utility of serial gene mutation tracking for locally advanced CRC in those who underwent curative resection following neoadjuvant chemotherapy. Methods We prospectively collected 10 locally advanced CRC cases for which curative resection was performed following preoperative neoadjuvant chemotherapy. Tissues from the primary tumour, distant metastatic tumours, and blood plasma were obtained during serial treatment. Comprehensive mutation analysis of 47 cancer-associated genes was performed using a pre-designed gene panel and next-generation sequencing. Results All cases showed a partial response to neoadjuvant chemotherapy, and pathological R0 resection was accomplished. In primary tumours, non-synonymous mutations were detected at between 1 and 14 sites before chemotherapy and at between 1 and 2 sites after. Founder mutations were precisely detected in blood plasma and metastatic tumours during longitudinal treatment. Conclusions Serial mutational analysis indicated that subclonal selection occurs during chemotherapy and that plasma can substitute for tumourous tissue in mutational analysis for drug selection and treatment decisions.

  Study JGAS000222

• Identification and Characterization of Cancer Mutations in Japanese LungAdenocarcinoma without Sequencing of Normal Tissue Counterparts

  We analyzed whole-exome sequencing data from 97 Japanese lung adenocarcinomapatients and identified several putative cancer-related genes and pathways. Particularly, we observed that cancer-related mutation patterns were significantly different between different ethnic groups. As previously reported, mutations in the EGFR gene were characteristic to Japanese, while those in the KRAS gene were more frequent in Caucasians. Furthermore, during the course of this analysis, we found that cancer-specific somatic mutations can be detected without sequencing normal tissue counterparts. 64% of the germline variants could be excluded using a total of 217 external Japanese exome datasets. We also show that a similar approach may beused for other three ethnic groups, although the discriminative power depends on the ethnic group. We demonstrate that the ATM gene and the PAPPA2 gene could be identified as cancer prognosis related genes. By bypassing the sequencing of normaltissue counterparts, this approach provides a useful means of not only reducing the time and cost of sequencing but also analyzing archive samples, for which normal tissue counterparts are not available.

  Study JGAS000001

• Non-invasive human skin transcriptome analysis using mRNA in skin surface lipids

  Non-invasive acquisition of mRNA data from the skin can be extremely useful for understanding skin physiology and diseases. Inspired by the holocrine process, in which the sebaceous glands secrete cell contents into the sebum, we focused on the possible presence of mRNAs in skin surface lipids (SSLs). We found that measurable levels of human mRNAs exist in SSLs, where the sebum protects them from degradation by RNases. The AmpliSeq transcriptome analysis was modified to measure SSL-RNA levels, and our results revealed that the SSL-RNAs predominantly comprised mRNAs derived from sebaceous glands, the epidermis, and hair follicles. Analysis of SSL-RNAs non-invasively collected from patients with atopic dermatitis revealed significantly increased expression of inflammation-related genes and decreased expression of terminal-differentiation���related genes, consistent with the results of previous reports. Further, we found that lipid-synthesis���related genes were downregulated in the sebaceous glands of patients with atopic dermatitis. These results indicate that the analysis of SSL-RNAs is a promising strategy to understand the pathophysiology of skin diseases.

  Study JGAS000418

• Immuno-genomic Profiling of Biopsy Specimens Predicts Neoadjuvant Chemotherapy Response in Esophageal Squamous Cell Carcinoma

  Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive cancers and is primarily treated with platinum-based neoadjuvant chemotherapy (NAC). Some ESCCs respond well to NAC. However, biomarkers to predict NAC sensitivity and their response mechanism in ESCC remain unclear. We introduce a model by machine learning and validated its potential to predict the NAC response in ESCC. To create this model, we performed whole genome sequencing and RNA-seq analysis on totally 141 ESCC biopsy specimens before NAC treatment and analyzed their immuno-genomic features and association with NAC response. Neutrophils infiltration could play an important role in ESCC response to NAC. We also demonstrated that specific copy number alterations and copy number signatures in the ESCC genome were significantly associated with NAC response. The interactions between the tumor genome and immune features of ESCC are likely to be a new indicator of therapeutic capability and a new therapeutic target for ESCC, and machine learning prediction for NAC response is useful.

  Study JGAS000535

• Non-invasive human skin transcriptome analysis using mRNA in skin surface lipids

  Non-invasive acquisition of mRNA data from the skin can be extremely useful for understanding skin physiology and diseases. Inspired by the holocrine process, in which the sebaceous glands secrete cell contents into the sebum, we focused on the possible presence of mRNAs in skin surface lipids (SSLs). We found that measurable levels of human mRNAs exist in SSLs, where the sebum protects them from degradation by RNases. The AmpliSeq transcriptome analysis was modified to measure SSL-RNA levels, and our results revealed that the SSL-RNAs predominantly comprised mRNAs derived from sebaceous glands, the epidermis, and hair follicles. Analysis of SSL-RNAs non-invasively collected from patients with atopic dermatitis revealed significantly increased expression of inflammation-related genes and decreased expression of terminal-differentiation���related genes, consistent with the results of previous reports. Further, we found that lipid-synthesis���related genes were downregulated in the sebaceous glands of patients with atopic dermatitis. These results indicate that the analysis of SSL-RNAs is a promising strategy to understand the pathophysiology of skin diseases.

  Study JGAS000417

• Fragmentomics Uncover Non-Mutational HRD Features

  Homologous recombination deficiency (HRD) is a key biomarker in prostate cancer (PCa), predicting response to PARP inhibitors and platinum-based therapies. However, current diagnostics often rely solely on BRCA1/2 mutations or genomic scars, missing cases driven by other mechanisms. Tissue-based testing is further limited by tumor heterogeneity and biopsy challenges in metastatic bone disease. Here, we applied a comprehensive multimodal approach to assess HRD in 106 advanced PCa patients using circulating tumor DNA (ctDNA). This included targeted sequencing of homologous recombination repair (HRR) genes, low-pass WGS for genomic instability (sHRD), WES for mutational signatures, and cfDNA fragmentomics and chromatin accessibility profiling. BRCA2 was the most frequently altered gene, often co-occurring with PTEN loss. High sHRD scores correlated with BRCA2/RB1 loss, somatic copy number alterations, and poor survival. HRD tumors showed enrichment of SBS3/ID6 signatures, altered fragment lengths, and reduced accessibility at zinc finger transcription factor sites. These results support ctDNA-based multimodal profiling as a non-invasive strategy for HRD detection and stratification.

  Study EGAS00001008190

• TGF-β signaling mediates microglial resilience to spatiotemporally restricted myelin degeneration

  Microglia survey and regulate central nervous system myelination during embryonic development and adult homeostasis. However, whether microglia-myelin interactions are spatiotemporally regulated remains unexplored. By examining spinal cord white matter tracts, we found that myelin degeneration was particularly prominent in the dorsal column (DC) during normal aging. This was accompanied by molecular and functional changes in DC microglia as well as an upregulation of TGF-β signaling. Disrupting TGF-β signaling in microglia led to unchecked microglial responses and myelin loss in the DC, accompanied by neurological deficits exacerbated with aging. snRNA-seq revealed the emergence of a TGF-β signaling-sensitive microglial subset and a disease-associated oligodendrocyte subset, both spatially restricted to the DC. We further discovered that microglia rely on a TGFβ autocrine mechanism to prevent damage of myelin in the DC. These findings demonstrate that TGF-β signaling is indispensable for maintaining microglial resilience to myelin degeneration in the DC during the aging process. This highlights a previously unresolved checkpoint mechanism of TGF-β signaling with regional specificity and spatially restricted microglia-oligodendrocyte interactions.

  Study EGAS50000001413

• Advancing fast in the analysis of circulating tumour DNA

  In cancer patients, solid tumours also release DNA fragments into the blood, and they are called Circulating Tumours DNA (ctDNA). Nowadays, the standard procedure for cancer monitoring is analysis of surgically obtained biopsies. They generate a big amount of material, but the operation is highly invasive and provide medical doctors with a single-time snapshot of the tumours, which are often highly changeable. Analysis of ctDNA, on the other hand, can provide continuous information regarding the tumour itself without the need of invasive procedures. This is why interest in this method is growing, and with it, the need for its technological optimization. Guanhua Zhu and colleagues, at the Genome Institute of Singapore, developed a methodology to quantify ctDNA burden, which means to estimate the amount of tumours derived circulating DNA among all cell-free DNA in the blood of individuals. Their work, published in Nature Communications in april 2021 and summarized in a sketch below, uses state-of-the art methods to analyse cfDNA degradation patterns at promoters and exon regions, to discern it from the DNA coming from the tumours. The bright point of their approach is that simultaneously enable for profiling of actionable cancer mutations and quantitative estimation of ctDNA burden. Their sequencing data of ctDNA has been deposited in the EGA under the accession number EGAS00001004657. This study sums up to a total of 37 of cfDNA and 36 about ctDNA present up to date in the EGA archive. The existence of cfDNA was firstly described back in 2002, while the use of ctDNA analysis in the oncological field exploded only after 2016. The approach is rapidly evolving, moving in parallel with the ever-improving sequencing technologies. Especially, the possibility to obtain high quality sequences from minimal amount of material is a crucial factor. Being able to alleviate cancer patients of disturbing and often slow-recovery procedures, while at the same time improving the quality of diagnosis and disease monitoring seems like a lot to ask. Thankfully, we are blessed with brilliant and dedicated scientists from all around the world who collaborate to make this a reality, sharing their results, knowledge and data.

  Blog advancing-fast-in-the-analysis-of-circulating-tumour-dna

• Bulk and single-cell RNA-sequencing data from five lines of human iPSC-derived (hiPSC-derived) astrocytes (3 in-house and 2 commercial lines), both alone and in co-culture with neurons, to define the molecular response of astrocytes to misfolded alpha-synuclein

  RNA editing is a post transcriptional mechanism that targets changes in RNA transcripts to modulate innate immune responses. We report the role of astrocyte specific, ADAR1 mediated RNA editing in neuroinflammation in Parkinson’s disease. We generated hiPSC-derived astrocytes, neurons and co-cultures and exposed them to small soluble alpha-synuclein aggregates. Oligomeric alpha-synuclein triggered an inflammatory glial state associated with TLR activation, viral responses, and cytokine secretion. This reactive state resulted in loss of neurosupportive functions, and the induction of neuronal toxicity. Notably, interferon response pathways were activated leading to upregulation, and isoform switching of the RNA deaminase enzyme, ADAR1. ADAR1 mediates A-to-I RNA editing, and increases in RNA editing were observed in inflammatory pathways in cells, as well as in post-mortem human PD brain. Aberrant, or dysregulated, ADAR1 responses and RNA editing may lead to sustained inflammatory reactive states in astrocytes triggered by alpha-synuclein aggregation, and this may drive the neuroinflammatory cascade in Parkinson’s.

  Study EGAS50000000751

• Gene expression adaptation of metastases to their host tissue

  The adaptation of metastatic cells to their host tissue critically determines the pathogenicity of a cancer and therefore patient survival. Yet, it remains elusive to what extent the host environment drives gene expression programs in metastatic cells. Here we identify adaptive mechanisms that enable metastases to establish themselves in a novel tissue context. We performed single-cell RNA-sequencing on malignant and benign tissue samples from untreated donors with colorectal adenocarcinoma and liver metastasis to deduce tissue adaptive expression patterns. A novel computational approach identified genes and pathways that consistently adapted to the host tissue at the transition from the primary tumor to the paired metastasis across donors. This analysis revealed that the majority of expression changes in the metastasis reflect an expression signature reminiscent of benign liver epithelial cells. Cellular processes adapting to the liver environment include basic cellular functions such as energy metabolism, as well as tissue-specific pathways such as the regulation of lipid metabolism by PPAR-α. These adaptations potentially increase the pathogenicity of the metastatic cells and may provide new therapeutic strategies.

  Study EGAS50000000817

• ABO: a 3D stroma-supported culture platform enabling full human B lymphopoiesis for disease modeling and gene therapy development

  Defective B-cell development underlies a large proportion of inborn errors of immunity, but progress in understanding disease mechanisms and of developing therapies has been limited by inadequate human in vitro models. Here, we establish a 3D aggregate culture platform composed of hematopoietic stem and progenitor cells (HSPCs) and mouse bone marrow stromal cells as an assay for efficient B-cell output (the ABO platform). ABOs supported progression through pro-B, pre-B, immature, and transitional B-cell stages, with a transcriptional profile and B-cell receptor (BCR) repertoire diversity closely resembling human bone marrow B-cell ontogeny. ABO-derived B cells exhibited functional signaling and differentiated into class-switched memory and antibody-secreting B cells following CD40-mediated stimulation. The ABO platform reproduced the arrest in B-cell development observed in RAG1-SCID patient–derived HSPCs, which was corrected by lentiviral RAG1 gene therapy. Thus, ABOs provide a clinically relevant platform for modeling B-cell immunodeficiencies and evaluating therapeutic strategies.

  Study EGAS50000001693

• HIV-phyloTSI: Subtype-independent estimation of time since HIV-1 infection for cross-sectional measures of population incidence using deep sequence data

  Estimating the time since HIV infection (TSI) at population level is essential for tracking changes in the global HIV epidemic. Most methods for determining TSI give a binary classification of infections as recent or non-recent within a window of several months, and cannot assess the cumulative impact of an intervention. We developed a Random Forest Regression model, HIV-phyloTSI, which combines measures of within-host diversity and divergence to generate continuous TSI estimates directly from viral deep-sequencing data, with no need for additional variables. HIV-phyloTSI provides a continuous measure of TSI up to 9 years, with a mean absolute error of less than 12 months overall and less than 5 months for infections with a TSI of up to a year. It performs equally well for all major HIV subtypes based on data from African and European cohorts. We demonstrate how HIV-phyloTSI can be used for incidence estimates on a population level.

  Study EGAS50000000895

• Human liver cholangiocyte organoids capture the heterogeneity of in vivo human liver ductal epithelium

  Human liver ductal epithelium is morphologically, functionally and transcriptionally heterogeneous. However, understanding the dynamics within human biliary/ductal epithelium has been hampered by the absence of an in vitro system that fully mimics its complex cellular heterogeneity. Here, we found that the human liver cholangiocyte (ductal-cell) organoids we previously published (Huch et al., 2015) are fairly homogenous and do not retain the cellular heterogeneity of the in vivo human biliary/ductal epithelium. Inspired by the knowledge of the in vivo niche, we refined our previous organoid culture medium to fully capture the cellular heterogeneity of the human ductal epithelium. We employed this refined system to analyse the interactions and relationships between the different human biliary epithelial cell states and discovered that acquiring a bipotent ductal cell state is necessary for differentiating the human ductal epithelium into functional hepatocyte-like cells. Our improved cholangiocyte organoid model represents a new platform to investigate cell plasticity and duct-to-hepatocyte differentiation in human liver.

  Study EGAS50000001000

• Relation between transcriptome, karyotype and age in cases of sex chromosome aneuploidies.

  Why women live longer than men is still an open question in human biology. Sex chromosomes have been proposed to play a role in the observed sex gap in longevity, and the Y male chromosome has been suspected of having a potential toxic genomic impact on male longevity. It has been hypothesized that transposable element (TE) repression declines with age, potentially leading to detrimental effects such as somatic mutations and disrupted gene expression, which may accelerate the aging process. Given that the Y chromosome is rich in repeats, age-related increases in TE expression could be more pronounced in males, likely contributing to their reduced longevity compared to females. In this work, we first studied whether TE expression is associated with the number of sex chromosomes in humans. We analyzed blood transcriptomic data obtained from individuals of different karyotype compositions: 46,XX females (normal female karyotype), 46,XY males (normal male karyotype), as well as males with abnormal karyotypes, such as 47,XXY, and 47,XYY.

  Study EGAS50000001009

• Dynamics of Tumor Heterogeneity from Primary to Metastatic Dissemination in Prostate Cancer

  PRO-SPeCT: PROstate cancer heterogeneity deconvolution through Single cell Profiling of Chromatin accessibility and Transcriptomic output Identifying drivers of cancer progression to guide treatment selection is hindered by limited abilities to understand tumor heterogeneity’s impact on evolution. Here, we delineated the phenotypic variability across ~300,000 prostate tumor cells collected from multiple loci in primary and matched locoregional metastases. We found inter-patient heterogeneity to be confined to malignant populations. While malignant cell populations exhibit intra-locus heterogeneity, they maintain inter-loci phenotypic similarity within a patient’s prostate gland. In addition, the intra-locus heterogeneity between malignant cell populations is paired with a common clonal architecture. Lastly, we show that malignant cell populations disseminating to locoregional lymph nodes mirror the clonal architecture and phenotypic heterogeneity observed across primary tumor loci while showcasing cell state transition toward inflammatory phenotypes. These findings provide insights into distinct measures of tumor heterogeneity, revealing diverse evolutionary paths across patients converging to common phenotypic adaptations in early prostate cancer progression.

  Study EGAS50000000524

• Human Dicer is required for cell-intrinsic immunity to self-dsRNA

  Self-derived double-stranded RNAs (self-dsRNAs) can activate cell-intrinsic innate immune responses and contribute to autoinflammation. We uncover an essential role for human Dicer in innate immune responses to self-dsRNA. Loss of Dicer disrupts RIG-I-like receptor-dependent type I interferon (IFN-I) induction and activation of both the PKR and OAS1-3/RNAse L pathway in conditions where self-dsRNA accumulates, such as cells lacking ADAR1, PNPase, hnRNPC, or MPP8. In contrast, Dicer does not affect the IFN-I response triggered by exogenous dsRNA. Dicer interacts with LGP2, G3BP1, and Staufen1 and loss of these proteins similarly impairs IFN-I induction by self-dsRNAs. Depletion of Dicer and G3BP1 reduces the accumulation of immunostimulatory self-dsRNAs, while depletion of Dicer and Staufen1 prevents MDA5 oligomerization. We conclude that Dicer regulates self-dsRNA availability and sensing, aided by G3BP1 and Staufen1, respectively. Our findings highlight a non-canonical role for Dicer in innate immune activation by self-dsRNA and pinpoint new drug targets in autoinflammatory disorders.

  Study EGAS50000001409

• Shifted assembly and function of mSWI/SNF family subcomplexes underlie targetable dependencies in endometriod carcinomas

  The mammalian SWI/SNF (mSWI/SNF) family of chromatin remodelers govern cell type-specific chromatin accessibility and gene expression and assemble as three distinct complexes: canonical BAF (cBAF), Polybromo-associated BAF (PBAF), and non-canonical BAF (ncBAF). ARID1A and ARID1B are paralog subunits that specifically nucleate the assembly of cBAF complexes and are frequently dual deleted in highly aggressive differentiated endometrial carcinomas (DECs). Here, in cellular models and primary human tumors, we find that ARID1A/B-mediated cBAF loss results in increased ncBAF and PBAF biochemical abundance and function genome-wide to maintain the DEC oncogenic signature. Further, treatment of ARID1A/1B-mutant cell lines and PDX models in vivo with a clinical-grade SMARCA4/2 ATPase inhibitor, FHD-286, markedly attenuates cell proliferation and tumor growth, and synergizes with carboplatin-based chemotherapy. Taken together, these findings reveal the oncogenic contributions of shifted of mSWI/SNF family complex abundance and chromatin-level gene regulatory functions and suggest therapeutic utility of mSWI/SNF complex small molecule inhibitors in dedifferentiated endometrial carcinoma and other cBAF-disrupted cancer types.

  Study EGAS50000001004

• Hofer et al., A specific subpopulation of cancer-associated fibroblasts promotes resistance to chemotherapy in triple-negative breast cancer by upregulating G0S2 protein

  Chemotherapy is the standard of care for patients with triple-negative breast cancer (TNBC), but the mechanisms of chemoresistance remain poorly understood. Here, we investigated the role of cancer associated fibroblasts (CAFs) in the chemotherapy response of TNBC, by combining in vivo analyses of TNBC patients with ex vivo cancer modeling, using tumor-on-chip (ToC) technology. Transcriptomic analysis revealed that the proportion of a specific CAF population, the extracellular matrix-producing myofibroblasts (ECM-myCAFs), is reduced after chemotherapy in chemo-sensitive, but not in chemo-resistant TNBC patients. In ToC devices, primary ECM-myCAFs promoted TNBC cell survival under Doxorubicin and Paclitaxel treatment. The mechanism of chemoresistance was elucidated by using single-cell RNA sequencing, advanced cell imaging and functional assays: ECM-myCAFs upregulate the G0/G1 switch 2 (G0S2) protein in TNBC cells, via activation of SRC family kinases. Altogether, our work identifies G0S2 as a new player in CAF mediated chemotherapy resistance in TNBC.

  Study EGAS50000000886

• Spatial transcriptomics analysis of triple negative breast cancers

  While triple negative breast cancer (TNBC) is known to be heterogeneous at the genomic and transcriptomic levels, spatial information on tumor organization and cell composition is still lacking. Here, we investigated TNBC tumor architecture including its microenvironment using spatial transcriptomics on a series of 92 patients. We performed an in-depth characterization of tumor and stroma organization and composition using an integrative approach combining histomorphological and spatial transcriptomics. Furthermore, a detailed molecular characterization of tertiary lymphoid structures led to identify a gene signature strongly associated to disease outcome and response to immunotherapy in several tumor types beyond TNBC. A stepwise clustering analysis identified nine TNBC ecotypes, further validated in external datasets. Several ecotypes were associated with disease outcome and characterized by potentially actionable features. In this work, we provideThis is the largest TNBC series providing a comprehensive insight into the complexity of TNBC ecosystem with potential clinical relevance, opening avenues for treatment tailoring including immunotherapy. All the processed data needed to replicate the results from the publication (counts, images, clinical data, etc) are available on Zenodo: https://zenodo.org/records/14204217

  Study EGAS50000000475

• Ancient tree-topologies and gene-flow processes among human lineages in Africa

  The deep history of human evolution in Africa remain intensely debated. We produced 73 novel high-quality whole genomes from 14 Central and Southern African populations with diverse cultural practices. With extensive simulations and machine-learning Approximate Bayesian Computation inferences, we reconstruct jointly their complex history of divergences and migrations. We find vast genome-wide diversity within and among populations, often uncorrelated with geography and cultural practices. This demonstrates the necessity to explicitly consider local genomic patterns, without merging samples indiscriminately into larger a priori categories, to reconstruct human evolutionary histories. We find that tree-like evolutions with long periods of drift between short periods of unidirectional gene-flow best explain the data, and that the lineage ancestral to Khoe-San populations diverged around 300,000 years ago from a lineage ancestral to rainforest hunter-gatherers and neighboring agriculturalists. We also find that short periods of ancient and recent gene-flow coincide with epochs of major ecological and cultural changes in Sub-Saharan Africa.

  Study EGAS50000001072

• High MAPK Activity Leading to Reduced WNT Signaling Drives Metastasis in Colorectal Cancer

  Colorectal cancer, a leading cause of cancer-related mortality due to distant metastases, is driven by activating mutations in the Wnt and MAPK pathways. Understanding the interplay between these crucial pathways during metastatic progression is essential for developing effective treatments. Here we developed an immunocompetent mouse model of metastatic colorectal cancer using in vivo orthotopic passaging. We demonstrate that highly metastatic tumor cells exhibit chromosomal amplifications in MAPK pathway genes, leading to increased MAPK activity, which in turn suppresses Wnt-associated transcriptional programs, including stem cell-associated genes. Inhibiting mutant KrasG12D effectively reversed this metastatic transcriptional state, reducing MAPK-driven gene expression and restoring Wnt activity. Notably, this treatment significantly curtailed lung metastases and reduced liver metastases during early seeding stages. Analysis of CRC patient data revealed that high MAPK activity and the associated metastatic gene signature correlated with poorer survival outcomes. These findings underscore that the plasticity of metastasis-initiating cells in CRC arises from the opposing roles of MAPK and Wnt signaling, despite their synergistic importance in colon tumor initiation.

  Study EGAS50000001231

• The brain neurovascular epigenome and its association with dementia

  Cerebral small vessel disease (SVD) is frequently comorbid with Alzheimer’s disease (AD) and vascular brain endothelial cells (BECs) are enriched for the expression of genes associated with AD genetic risk. However, the gene regulatory landscapes of neurovascular cells and their intersection with genetic risk for disease remains unexplored. Here we have generated gene regulomes for human BECs, mural cells and other brain cell types to show that AD heritability is primarily immune-related and that it shows modest enrichment in BECs. By contrast, genetic risk for SVD is enriched across cells of the neurovascular unit, including astrocytes. Enhancer-to-gene interactomes implicate amyloid processes in both AD and SVD, though the risk genes are mostly distinct for the two disorders. Motifs for putative partners of lineage transcription factors in microglia and BECs were enriched for AD and SVD variants at genes linked to disease pathways. Gene prioritization and enrichment analyses further identified potential repurposable drugs for AD. Our findings highlight novel regulatory mechanisms and therapeutic targets within the neurovascular system.

  Study EGAS50000001160

• RTEL1 mutation as a modifier of Dyskeratosis Congenita in a family with a Telomerase RNA (hTR) template mutation and variant telomeric repeats

  Vertebrate telomeres, the sequences protecting the end of linear chromosomes, are composed of conserved hexameric GGTTAG repeats. Here we present a C50>A telomerase RNA template mutation that results in the incorporation of the variant telomeric repeat GTTTAG in a family with dyskeratosis congenita primarily presenting as idiopathic pulmonary fibrosis. The mutant telomerase is characterized by decreased processivity in direct telomerase activity assays and in vivo based on data from Illumina next-generation whole genome sequencing and Oxford Nanopore Technologies long-read telomere sequencing. The latter provided positional mutant repeat information that revealed the inheritance and maintenance of proximal mutant repeats in individuals who did not inherit the template mutation. Additionally, we describe an RTEL1 nonsense mutation that is associated with very short telomeres in progeny harboring wild-type telomerase and inherited mutant telomeric repeats in the absence of overt clinical phenotypes. In contrast, co-inheritance of the RTEL1 nonsense and TERC r.C50>A mutations coincided with severe early-onset DC phenotypes in two individuals.

  Study EGAS50000001644