Biology subjects

Daniel, B.

Publications and source records attributed to Daniel, B..

At least 19 recordsLinked to original sources

bioRxiv2026

Preclinical Characterization of Hippo pathway inhibition: Insights from Pharmacological and Genetic Studies

The Hippo pathway is an evolutionarily conserved regulator of growth, regeneration, and organ homeostasis, and while its dysregulation is well established in cancer, the effects of inhibiting this pathway on normal tissues are less understood. Here we have systematically investigated the impact of Hippo pathway inhibition by comparing pharmacologic perturbation using a covalent small-molecule TEAD inhibitor (TEADi CMPD1, also known as GNE-8025) with genetic suppression of YAP/TAZ. We identified three key target organs that consistently emerged upon TEAD inhibition: the kidney, as well as the pancreas, and thymus. Across models, both perturbations led to comparable disease phenotypes in these organs, including tubular degeneration in the kidney, acinar atrophy in the pancreas, and lymphoid depletion in the thymus. However, the extent of damage was more pronounced in mice treated with the small-molecule inhibitor, highlighting potential dose and compound specific effects while remaining broadly consistent with the phenotypes observed upon genetic ablation of YAP/TAZ. This highlights the key role of evaluating both genetic and pharmacological perturbations to characterize the phenotypes and potential toxicities when modulating novel targets in oncology. To further investigate the mechanisms underlying pan-TEAD inhibition and kidney related adverse effects, we further characterized this class effect through a comprehensive transcriptomic analysis of the kidney to map the pathways involved in renal response. SignificanceUnderstanding on target toxicities is critical for the safe clinical development of TEAD inhibitors. Here, by integrating pharmacologic TEAD inhibition with genetic suppression by developing a mouse model that characterizes systemic, inducible knockdown of YAP/TAZ, we provide a systematic framework to define the Hippo pathway liabilities in vivo. We identify kidney, pancreas, and thymus as conserved target organs with concomitant phenotypes across both genetic and pharmacological methods, establishing these as pathway driven effects. Importantly, we uncover dose dependent and partially irreversible injury, particularly in kidney and pancreas, alongside mechanistic insight linking TEAD inhibition to aldosterone signaling disruption in kidney. These findings highlight the importance of strategies to identify monitorable, manageable adverse effect to guide clinical translation of TEAD targeting strategies.

cancer biology↗

bioRxiv2026

Multiomics profiling of APECED peripheral blood highlights compositional increases in alternatively activated B cell subsets

APECED (Autoimmune PolyEndocrinopathy Candidiasis Ectodermal Dystrophy) is a rare syndrome of multi-organ autoimmunity driven by the presence of self-reactive T cells and autoantibodies caused by mutations in the gene Autoimmune regulator (AIRE). Compared to the well-defined role of AIRE in establishing and maintaining T cell central tolerance, less is known about how AIRE deficiency impacts B cell phenotypes that may contribute to a breakdown in peripheral B cell tolerance. Here we analyzed serum and peripheral blood cells from APECED patients and healthy donors using autoantibody profiling, proteomics, flow cytometry, scRNAseq based subset analysis, BCRseq, and autoantigen binding assays finding significant changes to the APECED B cell compartment. We show that while Naive and Transitional B cells are reduced, alternatively activated B cell subsets are expanded in APECED patients including IgM CD27+ and class switched Atypical B cells which exhibit BCR chain features prone to autoreactivity. Antibodies derived from either APECED or Healthy class switched atypical B cells bind autoantigens at significantly higher rates than control IgG B cells. Serum autoantibodies and proteomics highlight APECED common and patient variable changes. These results together show that APECED causes a compositional shift towards subsets that may promote broken B cell tolerance and autoimmunity.

immunology↗

bioRxiv2026

Spatiotemporal profiling reveals the role of inflammatory niche in driving prostate cancer

Prostate cancer (PCa) is a lethal malignancy that displays profound resistance to immune checkpoint blockade (ICB), via mechanisms that are poorly understood. Here, we investigate the causes of CD8 T cell exhaustion and mechanisms of tumor progression in a PCa animal model, by single cell and spatial profiling, along a time course, following orthotopic transplantation of RB1/TP53/PTEN-deficient mouse organoids, competent to express neoantigens. The resulting tumors were castration resistant, consisting of largely basal and L2 malignant cells with upregulated inflammatory gene programs, and a specific spatial distribution of macrophages, cancer associated fibroblast (CAF) subtypes, and CD8 T-cells that was not previously reported. Using Zman-seq, we demonstrate that the effector function of tumor-infiltrating CD8 T cells was rapidly impaired as early as 24hrs after their infiltration, likely driven by signals from proinflammatory macrophages, Ccl2-Jak2+ inflammatory CAFs, and malignant basal cells, thus driving resistance to ICB. Interestingly, dual blockade of JAK1/2 and PD1 induced potent anti-tumor effects in tumor epithelial cells, decreased malignant epithelial cells and pro-inflammatory macrophages, and increased the proportion of normal (Pi16+) fibroblasts in the TME. Our results underscore the therapeutic potential of targeting JAK1/2 to enhance the efficacy of ICB, providing a rationale for clinical investigation of this combination in PCa.

cancer biology↗

bioRxiv2025

IRF2 degradation tunes the innate immune response

The transcription factor IRF2 protects against skin inflammation in mice and humans but, paradoxically, promotes pyroptosis by inducing Gsdmd. How IRF2 activates some proinflammatory genes, but suppresses others is unclear. We show that skin inflammation in Irf2-deficient mice is driven by IRF1 activation of interferon-stimulated genes (ISGs). Chromatin profiling revealed that IRF1 and IRF2 occupy the same ISG regulatory sites, but as a weaker transcriptional activator, IRF2 limited ISG transcription by IRF1. Toll-like receptor signaling favored IRF1-driven transcription by inducing Irf1. In addition, IRF1 recruited the ubiquitin ligase SPOP to ISG sites, resulting in proteasomal degradation of IRF2. This shift from IRF2 to IRF1 occupancy enhanced ISG transcription. Collectively, these findings define a hierarchical transcriptional circuit in which IRF2 limits IRF1 activity under homeostatic conditions but is displaced during an immune response, allowing IRF1-dependent gene programs central to innate immunity and autoinflammation.

immunology↗

bioRxiv2025

Clonal lineage tracing of innate immune cells in human cancer

Innate immune cells constitute the majority of the tumor microenvironment (TME), where they mediate both natural anti-tumor immunity and immunotherapy responses. While single-cell T- and B-cell receptor sequencing has provided fundamental insights into the clonal dynamics of human adaptive immunity, the lack of appropriate tools has precluded similar analysis of innate immune cells. Here, we describe a method that leverages somatic mitochondrial DNA (mtDNA) mutations to reconstruct clonal lineage relationships between single cells across cell types in native human tissues. We jointly sequenced single-cell transposase-accessible chromatin and mtDNA to profile n=124,958 cells from matched tumor, non-involved lung tissue (NILT), and peripheral blood of early-stage non-small cell lung cancer (NSCLC) patients, as well as n=93,757 cells from matched tumor and peripheral blood of ovarian cancer patients. Single-cell concomitant profiling of lineage and cell states of thousands of immune cells resolved clonality across cell types, tissue sites, and malignancies. Clonal tracing of innate immune cells demonstrates that TME-resident myeloid subsets, including macrophages and type 3 dendritic cells (DC3), are clonally linked to both circulating and tissue-infiltrating monocytes. Further, we identify distinct DC-biased and macrophage-biased myeloid clones, enriched in the tumor and NILT, respectively, and find that their circulating monocyte precursors exhibit distinct epigenetic profiles, suggesting that myeloid differentiation fate may be predetermined before TME infiltration. These results delineate the clonal pathways of intratumoral myeloid cell recruitment and differentiation in human cancer and suggest that remodeling of the tumor myeloid compartment may be peripherally programmed.

genomics↗

bioRxiv2025

Promoter-centric gene regulation in drug-resistant cancer

In eukaryotic cells, gene-distal regulatory elements (REs) facilitate long-range gene regulation, ensuring cell type-specific transcriptional programs. This mechanism is frequently disrupted in cancer, often driven by transcription factors (TFs) that serve as targets for cancer therapy. However, targeting these TFs can lead to acquired resistance mechanisms that are not fully understood. We demonstrate that mesothelioma cancer cells, dependent on the oncogenic driver TF family TEAD, develop resistance to a pan-TEAD inhibitor and revert to an evolutionarily ancient, promoter-centric gene regulatory mechanism to recover gene expression following TEAD inhibition. Base-pair-resolution 3D chromatin conformation mapping reveals that RE-promoter interactions are disrupted in resistant cells, despite epigenetic and transcriptomic recovery. Mechanistically, in resistant cells, TF complexes, including resistance-specific FOSL1 and KLF4, preferentially bind and enhance promoter activity to recover gene expression, rendering distal REs dispensable. Our findings highlight promoter elements and promoter-specific TFs as potential therapeutic targets using a model of drug-resistant cancer.

cancer biology↗

bioRxiv2024

TEAD-targeting small molecules induce a cofactor switch to regulate the Hippo pathway

TEAD proteins are the main transcriptional effectors of the Hippo signaling pathway and a pharmacological target in oncology. Most TEAD-targeting small molecules act by disrupting interaction with the oncogenic transcriptional activators YAP and TAZ. Here, we describe an alternative mechanism for TEAD lipid pocket binding molecules. We report that select sulfonamide-containing compounds promote TEAD interaction with the transcriptional repressor VGLL4 to induce a small molecule-mediated cofactor switch from YAP to VGLL4. Chemically induced VGLL4-TEAD complexes counteract YAP activity at chromatin to repress pro-growth gene networks, including genes involved in cellular proliferation and mechanosignaling. VGLL4 is required for an anti-proliferative response to these select compounds, and genetic deletion of VGLL4 causes resistance to these molecules in vitro and in vivo. Our data reveal a category of molecules that facilitate the repressive VGLL4-TEAD interaction and open up new understandings for curbing the oncogenic activity of Hippo pathway deregulation.

cancer biology↗

bioRxiv2024

Epigenomic programming of peripheral monocytes determines their transcriptional response to the tumor microenvironment

Classical monocytes are recruited to tumors and undergo transcriptional reprogramming resulting in tumor-promoting functions. Epigenomic features, such as post-translational modification of histones and chromatin accessibility, are key determinants of transcription factor binding and thereby play an important role in determining transcriptional responses to the tissue environment. It is unknown to what extent the epigenetic landscape of peripheral monocytes is rewired by cancer and how this could shape their transcriptional response upon recruitment to the tumor microenvironment. Here we used a combination of genome-wide assays for mRNA expression, chromatin accessibility and multiple histone modifications (H3K4me1, H3K4me3, H3K27ac) in a mouse model to investigate changes in the epigenomic landscape of peripheral monocytes. We then linked these epigenetic alterations to gene expression changes in monocytes occurring in the periphery or during tumor infiltration. We found that the distal tumor caused extensive remodeling of both H3K4me3+ promoters and H3K4me1+ enhancers in peripheral monocytes. Specifically, this involved the repression of interferon-responsive promoters and enhancers as well as the establishment of enhancers harboring binding motifs for transcription factors downstream of inflammatory and cytokine signaling pathways. The enhancers altered in the periphery could be linked to sustained gene expression changes which were less likely to be reversed in the tumor microenvironment. In addition, genes activated upon tumor infiltration showed prior epigenetic priming in peripheral monocytes. Overall, these results indicate that the epigenomic landscape of peripheral monocytes is altered in response to a distal tumor, and this could shape the transcriptional response of monocytes when they encounter microenvironmental signals upon infiltrating the tumor.

immunology↗

bioRxiv2024

Regulation of immune signal integration and memory by inflammation-induced chromosome conformation

3-dimensional (3D) genome conformation is central to gene expression regulation, yet our understanding of its contribution to rapid transcriptional responses, signal integration, and memory in immune cells is limited. Here, we study the molecular regulation of the inflammatory response in primary macrophages using integrated transcriptomic, epigenomic, and chromosome conformation data, including base pair-resolution Micro-Capture C. We demonstrate that interleukin-4 (IL-4) primes the inflammatory response in macrophages by stably rewiring 3D genome conformation, juxtaposing endotoxin-, interferon-gamma-, and dexamethasone-responsive enhancers in close proximity to their cognate gene promoters. CRISPR-based perturbations of enhancer-promoter contacts or CCCTC-binding factor (CTCF) boundary elements demonstrated that IL-4-driven conformation changes are indispensable for enhanced and synergistic endotoxin-induced transcriptional responses, as well as transcriptional memory following stimulus removal. Moreover, transcriptional memory mediated by changes in chromosome conformation often occurred in the absence of changes in chromatin accessibility or histone modifications. Collectively, these findings demonstrate that rapid and memory transcriptional responses to immunological stimuli are encoded in the 3D genome.

genomics↗

bioRxiv2023

mBARq: a versatile and user-friendly framework for the analysis of DNA barcodes from transposon insertion libraries, knockout mutants and isogenic strain populations

DNA barcoding has become a powerful tool for assessing the fitness of strains in a variety of studies, including random transposon mutagenesis screens, attenuation of site-directed mutants, and population dynamics of isogenic strain pools. However, the statistical analysis, visualization and contextualization of the data resulting from such experiments can be complex and require bioinformatic skills. Here, we developed mBARq, a user-friendly tool designed to simplify these steps for diverse experimental setups. The tool is seamlessly integrated with an intuitive web app for interactive data exploration via the STRING and KEGG databases to accelerate scientific discovery.

bioinformatics↗

bioRxiv2023

Disparate pathways for extrachromosomal DNA biogenesis and genomic DNA repair

Oncogene amplification on extrachromosomal DNA (ecDNA) is a pervasive driver event in cancer, yet our understanding of how ecDNA forms is limited. Here, we couple a CRISPR-based method for induction of ecDNA with extensive characterization of newly formed ecDNA to examine ecDNA biogenesis. We find that DNA circularization is efficient, irrespective of 3D genome context, with formation of a 1 Mb and 1.8 Mb ecDNA both reaching 15%. We show non-homologous end joining and microhomology mediated end joining both contribute to ecDNA formation, while inhibition of DNA-PKcs and ATM have opposing impacts on ecDNA formation. EcDNA and the corresponding chromosomal excision scar form at significantly different rates and respond differently to DNA-PKcs and ATM inhibition. Taken together, our results support a model of ecDNA formation in which double strand break ends dissociate from their legitimate ligation partners prior to joining of illegitimate ends to form the ecDNA and excision scar. SIGNIFICANCEOur study harnesses a CRISPR-based method to examine ecDNA biogenesis, uncovering efficient circularization between DSBs. ecDNAs and their corresponding chromosomal scars can form via NHEJ or MMEJ, but the ecDNA and scar formation processes are distinct. Based on our findings, we establish a mechanistic model of excisional ecDNA formation.

cancer biology↗

bioRxiv2023

Natural gene variation in Cannabis sativa unveils a key region of cannabinoid synthase enzymes

Cannabinoids are well-known specialised metabolites from the plant Cannabis sativa L. (cannabis). They exhibit various therapeutical to intoxicating psychoactive effects and have potential for medicinal applications. Among the enzymes involved in cannabinoid biosynthesis, cannabinoid oxidocyclases such as the tetrahydrocannabinolic acid (THCA) synthase play a key role in determining cannabis chemotype. To improve our understanding of cannabinoid oxidocyclase structure-function relationship, we proposed a new approach to targeted mutagenesis. By reviewing cannabis natural variation, three cannabinoid oxidocyclase mutations (S355N, CONF, G376R) associated to atypical plant chemotypes were selected. In-vitro characterization of THCA synthase mutants demonstrated these mutations significantly impact enzyme activity, correlating with the associated chemotype: S355N nearly inactivated the THCA synthase, CONF impaired CBGA metabolization and altered product specificity, while G376R drastically reduced enzyme activity and altered product specificity. In-silico docking experiments permitted to model the successive steps of THCA synthase substrate metabolization, revealing that the three mutations hamper substrate binding. Collectively, our results demonstrated how plant diversity can be leveraged to guide enzyme targeted mutagenesis, highlighted a key region of cannabinoid oxidocyclases, and permitted the establishment of a new model of the THCA synthase catalytic mechanism. This provides new insights into enzyme function, which can ultimately help developing medicinal cannabis cultivars and cannabinoid biotechnological production.

molecular biology↗

bioRxiv2023

Inosine Induces Stemness Features in CAR T cells and Enhances Potency

Adenosine (Ado) mediates immune suppression in the tumor microenvironment and exhausted CD8+ CAR T cells mediate Ado-induced immunosuppression through CD39/73-dependent Ado production. Knockout of CD39, CD73 or A2aR had modest effects on exhausted CAR T cells, whereas overexpression of Ado deaminase (ADA), which metabolizes Ado to inosine (INO), induced stemness features and potently enhanced functionality. Similarly, and to a greater extent, exposure of CAR T cells to INO augmented CAR T cell function and induced hallmark features of T cell stemness. INO induced a profound metabolic reprogramming, diminishing glycolysis and increasing oxidative phosphorylation, glutaminolysis and polyamine synthesis, and modulated the epigenome toward greater stemness. Clinical scale manufacturing using INO generated enhanced potency CAR T cell products meeting criteria for clinical dosing. These data identify INO as a potent modulator of T cell metabolism and epigenetic stemness programming and deliver a new enhanced potency platform for immune cell manufacturing. Statement of SignificanceAdenosine is well known to inhibit T cell function and substantial effort has focused on inhibiting adenosine generation and signaling. Here, we show that exhausted T cells are suppressed by adenosine, which is only modestly impacted by inhibiting adenosine generation or signaling. In contrast, metabolism of adenosine to inosine augmented T cell function and culture of T cells with inosine induced multi-level reprogramming leading to stemness and improved anti-tumor potency. We demonstrate the feasibility of introducing inosine during GMP cell manufacturing as a novel strategy to generate enhanced CAR-T cells.

immunology↗

bioRxiv2023

Codon affinity in mitochondrial DNA shapes evolutionary and somatic fitness

Summary ParagraphSomatic variation contributes to biological heterogeneity by modulating cellular proclivity to differentiate, expand, adapt, or die. While large-scale sequencing efforts have revealed the foundational role of somatic variants to drive human tumor evolution, our understanding of the contribution of mutations to modulate cellular fitness in non-malignant contexts remains understudied. Here, we identify a mosaic synonymous variant (m.7076A>G) in the mitochondrial DNA (mtDNA) encoded cytochrome c-oxidase subunit 1 gene (MT-CO1, p.Gly391=), which was present at homoplasmy in 47% of immune cells from a healthy donor. Using single-cell multi-omics, we discover highly specific selection against the m.7076G mutant allele in the CD8+ effector memory T cell compartment in vivo, reminiscent of selection observed for pathogenic mtDNA alleles1, 2 and indicative of lineage-specific metabolic requirements. While the wildtype m.7076A allele is translated via Watson-Crick-Franklin base-pairing, the anticodon diversity of the mitochondrial transfer RNA pool is limited, requiring wobble-dependent translation of the m.7076G mutant allele. Notably, mitochondrial ribosome profiling revealed altered codon-anticodon affinity at the wobble position as evidenced by stalled translation of the synonymous m.7076G mutant allele encoding for glycine. Generalizing this observation, we provide a new ontogeny of the 8,482 synonymous variants in the human mitochondrial genome that enables interpretation of functional mtDNA variation. Specifically, via inter- and intra-species evolutionary analyses, population-level complex trait associations, and the occurrence of germline and somatic mtDNA mutations from large-scale sequencing studies, we demonstrate that synonymous variation impacting codon:anticodon affinity is actively evolving across the entire mitochondrial genome and has broad functional and phenotypic effects. In summary, our results introduce a new ontogeny for mitochondrial genetic variation and support a model where organismal principles can be discerned from somatic evolution via single-cell genomics.

genetics↗

bioRxiv2022

Enhanced Effector Activity of Mediator Kinase Module Deficient CAR-T Cells

Adoptive T cell immune therapies mediate impressive clinical benefit in a fraction of patients, but anti-tumor effects are often limited by inadequate T cell potency. To identify genes limiting T cell effector function, we conducted genome-wide CRISPR knock-out screens in human primary CAR-T cells. The top hits were MED12 and CCNC, components of the cyclin-dependent kinase (CDK) module of the Mediator complex, an evolutionarily conserved regulator of gene transcription. MED12 or CCNC deficient CAR-T cells manifest increased expansion, cytokine production, metabolic fitness, effector function, anti-tumor activity and reduced terminal effector differentiation. Chemical inhibition of CDK8/19 kinase activity recapitulated some features of genetic loss of MED12, including increased T cell expansion. MED12 deficient CAR-T cells showed widespread but selective increases in chromatin accessibility, MED1 chromatin occupancy, and H3K27 acetylation at enhancers used by transcription factors playing a critical role in T cell fate, including several STAT and AP1 family members. The most pronounced enhancement was observed for STAT5 which manifested as increased sensitivity to IL-2 in MED12 deficient T cells. These results link Mediator induced transcriptional coactivation with T cell effector programming and identify the CDK module as a target for enhancing the potency of anti-tumor T cell responses. One Sentence SummaryThe Mediator kinase module is a primary regulator of T cell differentiation, and genetic or small molecule-based inhibition of this module enhances effector T cell potency.

immunology↗

bioRxiv2022

A unique epigenomic landscape defines CD8+ tissue-resident memory T cells

Memory T cells provide rapid and long-term protection against infection and tumors. The memory CD8+ T cell repertoire contains phenotypically and transcriptionally heterogeneous subsets with specialized functions and recirculation patterns. While these T cell populations have been well characterized in terms of differentiation potential and function, the epigenetic changes underlying memory T cell fate determination and tissue-residency remain largely unexplored. Here, we examined the single-cell chromatin landscape of CD8+ T cells over the course of acute viral infection. We reveal an early bifurcation of memory precursors displaying distinct chromatin accessibility and define epigenetic trajectories that lead to a circulating (TCIRC) or tissue-resident memory T (TRM) cell fate. While TRM cells displayed a conserved epigenetic signature across organs, we demonstrate that these cells exhibit tissue-specific signatures and identify transcription factors that regulate TRM cell populations in a site-specific manner. Moreover, we demonstrate that TRM cells and exhausted T (TEX) cells are distinct epigenetic lineages that are distinguishable early in their differentiation. Together, these findings show that TRM cell development is accompanied by dynamic alterations in chromatin accessibility that direct a unique transcriptional program resulting in a tissue-adapted and functionally distinct T cell state. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=192 HEIGHT=200 SRC="FIGDIR/small/490680v1_ufig1.gif" ALT="Figure 1"> View larger version (56K): org.highwire.dtl.DTLVardef@b03f1corg.highwire.dtl.DTLVardef@ff6871org.highwire.dtl.DTLVardef@220db2org.highwire.dtl.DTLVardef@1b15166_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIscATAC atlas reveals the epigenetic variance of memory CD8+ T cell subsets over the course of acute infection C_LIO_LIEarly bifurcation of memory precursors leads to circulating versus tissue-resident cell fates C_LIO_LIIntegrating transcriptional and epigenetic analyses identified organ-specific TRM cell regulators including HIC1 and BACH2 C_LIO_LIEpigenetic distinction of TRM cells and TEX cell subsets C_LI

immunology↗

bioRxiv2021

Divergent clonal differentiation trajectories of T cell exhaustion

T cells activated by chronic antigen exposure in the setting of viral infections or cancer can adopt an exhausted T cell (Tex) state, characterized by reduced effector function and proliferative capacity, and the upregulation of inhibitory receptors. However, whether all antigen-specific T cell clones follow the same molecular and cellular Tex differentiation trajectory remains unclear. Here, we generate a single-cell multi-omic atlas of T cell exhaustion that redefines the phenotypic diversity and molecular regulation of Tex phenotypes. Longitudinal analysis during chronic viral infection identifies an early effector phenotype that is epigenetically primed for Tex differentiation and two late-stage Tex cell states with either a terminal exhaustion or a killer cell lectin-like receptor (KLR)-expressing cytotoxic gene signature. We define clonal trajectories of antigen-specific T cells using paired single-cell RNA and T cell receptor sequencing and reveal distinct differentiation trajectories resulting in terminal Tex-biased, KLR Tex-biased, or divergent clones that differentiate into both phenotypes. Comparison of Tex phenotypes among shared T cell clones that traffic to multiple organs reveals that clonal differentiation trajectories are maintained across tissues. Finally, we show that differences in clonal differentiation trajectory are driven by TCR signal strength, whereby high-affinity T cell clones preferentially adopt a terminal Tex fate, while low-affinity clones adopt an effector-like KLR Tex fate that is detectable long-term but depleted in high antigen settings. These findings reveal clonal heterogeneity in the T cell response to chronic antigen and genomic programs that underlie Tex fates and persistence. HighlightsO_LIA single-cell atlas of T cell exhaustion identifies novel early effector and KLR Tex states. C_LIO_LIClonal T cell analysis defines divergent differentiation trajectories during chronic viral infection leading to terminal and KLR Tex fates. C_LIO_LIThe heterogeneity of the Tex pool arises from three primary differentiation patterns and are differentially persistent in the setting of high antigen. C_LIO_LIClonal Tex differentiation patterns are conserved across organ sites and driven by TCR signal strength. C_LI

immunology↗

bioRxiv2021

Clonal hematopoiesis is driven by aberrant activation of TCL1A

A diverse set of driver genes, such as regulators of DNA methylation, RNA splicing, and chromatin remodeling, have been associated with pre-malignant clonal expansion of hematopoietic stem cells (HSCs). The factors mediating expansion of these mutant clones remain largely unknown, partially due to a paucity of large cohorts with longitudinal blood sampling. To circumvent this limitation, we developed and validated a method to infer clonal expansion rate from single timepoint data called PACER (passenger-approximated clonal expansion rate). Applying PACER to 5,071 persons with clonal hematopoiesis accurately recapitulated the known fitness effects due to different driver mutations. A genome-wide association study of PACER revealed that a common inherited polymorphism in the TCL1A promoter was associated with slower clonal expansion. Those carrying two copies of this protective allele had up to 80% reduced odds of having driver mutations in TET2, ASXL1, SF3B1, SRSF2, and JAK2, but not DNMT3A. TCL1A was not expressed in normal or DNMT3A-mutated HSCs, but the introduction of mutations in TET2 or ASXL1 by CRISPR editing led to aberrant expression of TCL1A and expansion of HSCs in vitro. These effects were abrogated in HSCs from donors carrying the protective TCL1A allele. Our results indicate that the fitness advantage of multiple common driver genes in clonal hematopoiesis is mediated through TCL1A activation. PACER is an approach that can be widely applied to uncover genetic and environmental determinants of pre-malignant clonal expansion in blood and other tissues.

genetics↗