Life Sciences Research for Lifelong Health

Publications

The Babraham Institute Publications database contains details of all publications resulting from our research groups and scientific services.

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Title / Authors / Details Open Access Download

Epigenetic regulation in development: is the mouse a good model for the human?
Hanna CW, Demond H, Kelsey G

Over the past few years, advances in molecular technologies have allowed unprecedented mapping of epigenetic modifications in gametes and during early embryonic development. This work is allowing a detailed genomic analysis, which for the first time can answer long-standing questions about epigenetic regulation and reprogramming, and highlights differences between mouse and human, the implications of which are only beginning to be explored.

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Human reproduction update, , 1460-2369, , 2018

PMID: 29992283


Cold-induced epigenetic programming of the sperm enhances brown adipose tissue activity in the offspring.
Sun W, Dong H, Becker AS, Dapito DH, Modica S, Grandl G, Opitz L, Efthymiou V, Straub LG, Sarker G, Balaz M, Balazova L, Perdikari A, Kiehlmann E, Bacanovic S, Zellweger C, Peleg-Raibstein D, Pelczar P, Reik W, Burger IA, von Meyenn F, Wolfrum C

Recent research has focused on environmental effects that control tissue functionality and systemic metabolism. However, whether such stimuli affect human thermogenesis and body mass index (BMI) has not been explored. Here we show retrospectively that the presence of brown adipose tissue (BAT) and the season of conception are linked to BMI in humans. In mice, we demonstrate that cold exposure (CE) of males, but not females, before mating results in improved systemic metabolism and protection from diet-induced obesity of the male offspring. Integrated analyses of the DNA methylome and RNA sequencing of the sperm from male mice revealed several clusters of co-regulated differentially methylated regions (DMRs) and differentially expressed genes (DEGs), suggesting that the improved metabolic health of the offspring was due to enhanced BAT formation and increased neurogenesis. The conclusions are supported by cell-autonomous studies in the offspring that demonstrate an enhanced capacity to form mature active brown adipocytes, improved neuronal density and more norepinephrine release in BAT in response to cold stimulation. Taken together, our results indicate that in humans and in mice, seasonal or experimental CE induces an epigenetic programming of the sperm such that the offspring harbor hyperactive BAT and an improved adaptation to overnutrition and hypothermia.

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Nature medicine, , 1546-170X, , 2018

PMID: 29988127


Translational repression of pre-formed cytokine-encoding mRNA prevents chronic activation of memory T cells.
Salerno F, Engels S, van den Biggelaar M, van Alphen FPJ, Guislain A, Zhao W, Hodge DL, Bell SE, Medema JP, von Lindern M, Turner M, Young HA, Wolkers MC

Memory T cells are critical for the immune response to recurring infections. Their instantaneous reactivity to pathogens is empowered by the persistent expression of cytokine-encoding mRNAs. How the translation of proteins from pre-formed cytokine-encoding mRNAs is prevented in the absence of infection has remained unclear. Here we found that protein production in memory T cells was blocked via a 3' untranslated region (3' UTR)-mediated process. Germline deletion of AU-rich elements (AREs) in the Ifng-3' UTR led to chronic cytokine production in memory T cells. This aberrant protein production did not result from increased expression and/or half-life of the mRNA. Instead, AREs blocked the recruitment of cytokine-encoding mRNA to ribosomes; this block depended on the ARE-binding protein ZFP36L2. Thus, AREs mediate repression of translation in mouse and human memory T cells by preventing undesirable protein production from pre-formed cytokine-encoding mRNAs in the absence of infection.

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Nature immunology, , 1529-2916, , 2018

PMID: 29988089


Antigen phagocytosis by B cells is required for a potent humoral response.
Martínez-Riaño A, Bovolenta ER, Mendoza P, Oeste CL, Martín-Bermejo MJ, Bovolenta P, Turner M, Martínez-Martín N, Alarcón B

Successful vaccines rely on activating a functional humoral response that results from promoting a proper germinal center (GC) reaction. Key in this process is the activation of follicular B cells that need to acquire antigens and to present them to cognate CD4 T cells. Here, we report that follicular B cells can phagocytose large antigen-coated particles, a process thought to be exclusive of specialized antigen-presenting cells such as macrophages and dendritic cells. We show that antigen phagocytosis by B cells is BCR-driven and mechanistically dependent on the GTPase RhoG. Using mice, we show that phagocytosis of antigen by B cells is important for the development of a strong GC response and the generation of high-affinity class-switched antibodies. Importantly, we show that the potentiation effect of alum, a common vaccine adjuvant, requires direct phagocytosis of alum-antigen complexes by B cells. These data suggest a new avenue for vaccination approaches by aiming to deliver 1-3 μm size antigen particles to follicular B cells.

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EMBO reports, , 1469-3178, , 2018

PMID: 29987136


Open Access

Removing physiological motion from intravital and clinical functional imaging data.
Warren SC, Nobis M, Magenau A, Mohammed YH, Herrmann D, Moran I, Vennin C, Conway JR, Mélénec P, Cox TR, Wang Y, Morton JP, Welch HC, Strathdee D, Anderson KI, Phan TG, Roberts MS, Timpson P

Intravital microscopy can provide unique insights into the function of biological processes in a native context. However, physiological motion caused by peristalsis, respiration and the heartbeat can present a significant challenge, particularly for functional readouts such as fluorescence lifetime imaging (FLIM), which require longer acquisition times to obtain a quantitative readout. Here, we present and benchmark , a versatile multi-platform software tool for image-based correction of sample motion blurring in both time resolved and conventional laser scanning fluorescence microscopy data in two and three dimensions. We show that is able to resolve intravital FLIM-FRET images of intra-abdominal organs in murine models and NADH autofluorescence of human dermal tissue imaging subject to a wide range of physiological motions. Thus, can enable FLIM imaging in situations where a stable imaging platform is not always possible and rescue previously discarded quantitative imaging data.

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eLife, 7, 2050-084X, , 2018

PMID: 29985127


Open Access

Promoter interactome of human embryonic stem cell-derived cardiomyocytes connects GWAS regions to cardiac gene networks.
Choy MK, Javierre BM, Williams SG, Baross SL, Liu Y, Wingett SW, Akbarov A, Wallace C, Freire-Pritchett P, Rugg-Gunn PJ, Spivakov M, Fraser P, Keavney BD

Long-range chromosomal interactions bring distal regulatory elements and promoters together to regulate gene expression in biological processes. By performing promoter capture Hi-C (PCHi-C) on human embryonic stem cell-derived cardiomyocytes (hESC-CMs), we show that such promoter interactions are a key mechanism by which enhancers contact their target genes after hESC-CM differentiation from hESCs. We also show that the promoter interactome of hESC-CMs is associated with expression quantitative trait loci (eQTLs) in cardiac left ventricular tissue; captures the dynamic process of genome reorganisation after hESC-CM differentiation; overlaps genome-wide association study (GWAS) regions associated with heart rate; and identifies new candidate genes in such regions. These findings indicate that regulatory elements in hESC-CMs identified by our approach control gene expression involved in ventricular conduction and rhythm of the heart. The study of promoter interactions in other hESC-derived cell types may be of utility in functional investigation of GWAS-associated regions.

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Nature communications, 9, 2041-1723, 2526, 2018

PMID: 29955040


Host lipidome analysis during rhinovirus replication in human bronchial epithelial cells identifies potential therapeutic targets.
Nguyen A, Guedan A, Mousnier A, Swieboda D, Zhang Q, Horkai D, Le Novere N, Solari R, Wakelam MJO

In patients with asthma or chronic obstructive pulmonary disease rhinovirus infections can provoke acute worsening of disease and limited treatment options exist. Viral replication in the host cell induces significant remodeling of intracellular membranes, but few studies have explored this mechanistically or as a therapeutic opportunity. We performed unbiased lipidomic analysis on human bronchial epithelial cells infected over a 6 hour period with the RV-A1b strain of rhinovirus to determine changes in 493 distinct lipid species. Through pathway and network analysis we identified temporal changes in the apparent activities of a number of lipid metabolizing and signaling enzymes. In particular, analysis highlighted fatty acid synthesis and ceramide metabolism as potential anti-rhinoviral targets. To validate the importance of these enzymes in viral replication, we explored the effects of commercially-available enzyme inhibitors upon RV-A1b infection and replication. Ceranib-1, D609 and C75 were the most potent inhibitors, which confirmed that fatty acid synthase and ceramidase are potential inhibitory targets in rhinoviral infections. More broadly, this study demonstrates the potential of lipidomics and pathway analysis to identify novel targets to treat human disorders.

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Journal of lipid research, , 1539-7262, , 2018

PMID: 29946055


Open Access

Autophagy, Inflammation, and Metabolism (AIM) Center of Biomedical Research Excellence: supporting the next generation of autophagy researchers and fostering international collaborations.
Deretic V, Prossnitz E, Burge M, Campen MJ, Cannon J, Liu KJ, Sklar LA, Allers L, Garcia SA, Baehrecke EH, Behrends C, Cecconi F, Codogno P, Chen GC, Elazar Z, Eskelinen EL, Fourie B, Gozuacik D, Hong W, Hotamisligi G, Jäättelä M, Jo EK, Johansen T, Juhász G, Kimchi A, Ktistakis N, Kroemer G, MIzushima N, Münz C, Reggiori F, Rubinsztein D, Ryan K, Schroder K, Simonsen A, Tooze S, Vaccaro M, Yoshimori T, Yu L, Zhang H, Klionsky DJ

Recently, NIH has funded a center for autophagy research named the Autophagy, Inflammation, and Metabolism (AIM) Center of Biomedical Research Excellence, located at the University of New Mexico Health Science Center (UNM HSC), with aspirations to promote autophagy research locally, nationally, and internationally. The center has 3 major missions: (i) to support junior faculty in their endeavors to develop investigations in this area and obtain independent funding; (ii) to develop and provide technological platforms to advance autophagy research with emphasis on cellular approaches for high quality reproducible research; and (iii) to foster international collaborations through the formation of an International Council of Affiliate Members and through hosting national and international workshops and symposia. Scientifically, the AIM center is focused on autophagy and its intersections with other processes, with emphasis on both fundamental discoveries and applied translational research.

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Autophagy, , 1554-8635, , 2018

PMID: 29938597


Mitochondria maintain controlled activation state of epithelial-resident T lymphocytes.
Konjar Š, Frising UC, Ferreira C, Hinterleitner R, Mayassi T, Zhang Q, Blankenhaus B, Haberman N, Loo Y, Guedes J, Baptista M, Innocentin S, Stange J, Strathdee D, Jabri B, Veldhoen M

Epithelial-resident T lymphocytes, such as intraepithelial lymphocytes (IELs) located at the intestinal barrier, can offer swift protection against invading pathogens. Lymphocyte activation is strictly regulated because of its potential harmful nature and metabolic cost, and most lymphocytes are maintained in a quiescent state. However, IELs are kept in a heightened state of activation resembling effector T cells but without cytokine production or clonal proliferation. We show that this controlled activation state correlates with alterations in the IEL mitochondrial membrane, especially the cardiolipin composition. Upon inflammation, the cardiolipin composition is altered to support IEL proliferation and effector function. Furthermore, we show that cardiolipin makeup can particularly restrict swift IEL proliferation and effector functions, reducing microbial containment capability. These findings uncover an alternative mechanism to control cellular activity, special to epithelial-resident T cells, and a novel role for mitochondria, maintaining cells in a metabolically poised state while enabling rapid progression to full functionality.

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Science immunology, 3, 2470-9468, , 2018

PMID: 29934344


The Calcineurin Inhibitor Tacrolimus Specifically Suppresses Human T Follicular Helper Cells.
Wallin EF, Hill DL, Linterman MA, Wood KJ

T follicular helper (Tfh) cells are key players in the production of antibody-producing B cells the germinal center reaction. Therapeutic strategies targeting Tfh cells are important where antibody formation is implicated in disease, such as transplant rejection and autoimmune diseases. We investigated the impact of the immunosuppressive agent tacrolimus on human Tfh cell differentiation and function in transplant recipients.

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Frontiers in immunology, 9, 1664-3224, 1184, 2018

PMID: 29904381


Open Access

Profiling of phosphoinositide molecular species in human and mouse platelets identifies new species increasing following stimulation.
Mujalli A, Chicanne G, Bertrand-Michel J, Viars F, Stephens L, Hawkins P, Viaud J, Gaits-Iacovoni F, Severin S, Gratacap MP, Terrisse AD, Payrastre B

Phosphoinositides are bioactive lipids essential in the regulation of cell signaling as well as cytoskeleton and membrane dynamics. Their metabolism is highly active in blood platelets where they play a critical role during activation, at least through two well identified pathways involving phospholipase C and phosphoinositide 3-kinases (PI3K). Here, using a sensitive high-performance liquid chromatography-mass spectrometry method recently developed, we monitored for the first time the profiling of phosphatidylinositol (PI), PIP, PIP and PIP molecular species (fatty-acyl profiles) in human and mouse platelets during the course of stimulation by thrombin and collagen-related peptide. Furthermore, using class IA PI3K p110α or p110β deficient mouse platelets and a pharmacological inhibitor, we show the crucial role of p110β and the more subtle role of p110α in the production of PIP molecular species following stimulation. This comprehensive platelet phosphoinositides profiling provides important resources for future studies and reveals new information on phosphoinositides biology, similarities and differences in mouse and human platelets and unexpected dramatic increase in low-abundance molecular species of PIP during stimulation, opening new perspectives in phosphoinositide signaling in platelets.

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Biochimica et biophysica acta, , 0006-3002, , 2018

PMID: 29902570


Uncovering the Role of RNA-Binding Proteins in Gene Expression in the Immune System.
Díaz-Muñoz MD, Turner M

Fighting external pathogens requires an ever-changing immune system that relies on tight regulation of gene expression. Transcriptional control is the first step to build efficient responses while preventing immunodeficiencies and autoimmunity. Post-transcriptional regulation of RNA editing, location, stability, and translation are the other key steps for final gene expression, and they are all controlled by RNA-binding proteins (RBPs). Nowadays we have a deep understanding of how transcription factors control the immune system but recent evidences suggest that post-transcriptional regulation by RBPs is equally important for both development and activation of immune responses. Here, we review current knowledge about how post-transcriptional control by RBPs shapes our immune system and discuss the perspective of RBPs being the key players of a hidden immune cell epitranscriptome.

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Frontiers in immunology, 9, 1664-3224, 1094, 2018

PMID: 29875770


Open Access

Compensation between CSF1R+ macrophages and Foxp3+ Treg cells drives resistance to tumor immunotherapy.
Gyori D, Lim EL, Grant FM, Spensberger D, Roychoudhuri R, Shuttleworth SJ, Okkenhaug K, Stephens LR, Hawkins PT

Redundancy and compensation provide robustness to biological systems but may contribute to therapy resistance. Both tumor-associated macrophages (TAMs) and Foxp3+ regulatory T (Treg) cells promote tumor progression by limiting antitumor immunity. Here we show that genetic ablation of CSF1 in colorectal cancer cells reduces the influx of immunosuppressive CSF1R+ TAMs within tumors. This reduction in CSF1-dependent TAMs resulted in increased CD8+ T cell attack on tumors, but its effect on tumor growth was limited by a compensatory increase in Foxp3+ Treg cells. Similarly, disruption of Treg cell activity through their experimental ablation produced moderate effects on tumor growth and was associated with elevated numbers of CSF1R+ TAMs. Importantly, codepletion of CSF1R+ TAMs and Foxp3+ Treg cells resulted in an increased influx of CD8+ T cells, augmentation of their function, and a synergistic reduction in tumor growth. Further, inhibition of Treg cell activity either through systemic pharmacological blockade of PI3Kδ, or its genetic inactivation within Foxp3+ Treg cells, sensitized previously unresponsive solid tumors to CSF1R+ TAM depletion and enhanced the effect of CSF1R blockade. These findings identify CSF1R+ TAMs and PI3Kδ-driven Foxp3+ Treg cells as the dominant compensatory cellular components of the immunosuppressive tumor microenvironment, with implications for the design of combinatorial immunotherapies.

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JCI insight, 3, 2379-3708, , 2018

PMID: 29875321


Open Access

Phosphoinositide 3-kinase δ inhibition promotes antitumor responses but antagonizes checkpoint inhibitors.
Lim EL, Cugliandolo FM, Rosner DR, Gyori D, Roychoudhuri R, Okkenhaug K

Multiple modes of immunosuppression restrain immune function within tumors. We previously reported that phosphoinositide 3-kinase δ (PI3Kδ) inactivation in mice confers resistance to a range of tumor models by disrupting immunosuppression mediated by regulatory T cells (Tregs). The PI3Kδ inhibitor idelalisib has proven highly effective in the clinical treatment of chronic lymphocytic leukemia and the potential to extend the use of PI3Kδ inhibitors to nonhematological cancers is being evaluated. In this work, we demonstrate that the antitumor effect of PI3Kδ inactivation is primarily mediated through the disruption of Treg function, and correlates with tumor dependence on Treg immunosuppression. Compared with Treg-specific PI3Kδ deletion, systemic PI3Kδ inactivation is less effective at conferring resistance to tumors. We show that PI3Kδ deficiency impairs the maturation and reduces the capacity of CD8+ cytotoxic T lymphocytes (CTLs) to kill tumor cells in vitro, and to respond to tumor antigen-specific immunization in vivo. PI3Kδ inactivation antagonized the antitumor effects of tumor vaccines and checkpoint blockade therapies intended to boost the CD8+ T cell response. These findings provide insights into mechanisms by which PI3Kδ inhibition promotes antitumor immunity and demonstrate that the mechanism is distinct from that mediated by immune checkpoint blockade.

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JCI insight, 3, 2379-3708, , 2018

PMID: 29875319


Open Access

Systems medicine disease maps: community-driven comprehensive representation of disease mechanisms.
Mazein A, Ostaszewski M, Kuperstein I, Watterson S, Le Novère N, Lefaudeux D, De Meulder B, Pellet J, Balaur I, Saqi M, Nogueira MM, He F, Parton A, Lemonnier N, Gawron P, Gebel S, Hainaut P, Ollert M, Dogrusoz U, Barillot E, Zinovyev A, Schneider R, Balling R, Auffray C

The development of computational approaches in systems biology has reached a state of maturity that allows their transition to systems medicine. Despite this progress, intuitive visualisation and context-dependent knowledge representation still present a major bottleneck. In this paper, we describe the Disease Maps Project, an effort towards a community-driven computationally readable comprehensive representation of disease mechanisms. We outline the key principles and the framework required for the success of this initiative, including use of best practices, standards and protocols. We apply a modular approach to ensure efficient sharing and reuse of resources for projects dedicated to specific diseases. Community-wide use of disease maps will accelerate the conduct of biomedical research and lead to new disease ontologies defined from mechanism-based disease endotypes rather than phenotypes.

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NPJ systems biology and applications, 4, 2056-7189, 21, 2018

PMID: 29872544


Open Access

Publisher Correction: TDP-43 gains function due to perturbed autoregulation in a Tardbp knock-in mouse model of ALS-FTD.
White MA, Kim E, Duffy A, Adalbert R, Phillips BU, Peters OM, Stephenson J, Yang S, Massenzio F, Lin Z, Andrews S, Segonds-Pichon A, Metterville J, Saksida LM, Mead R, Ribchester RR, Barhomi Y, Serre T, Coleman MP, Fallon JR, Bussey TJ, Brown RH, Sreedharan J

In the version of this article initially published, the footnote number 17 was missing from the author list for the two authors who contributed equally. Also, the authors have added a middle initial for author Justin R. Fallon and an acknowledgement to the Babraham Institute Imaging Facility and Sequencing Core Facility. The errors have been corrected in the HTML and PDF versions of the article.

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Nature neuroscience, , 1546-1726, , 2018

PMID: 29872124


Non-Invasive Multiphoton Imaging of Islets Transplanted Into the Pinna of the NOD Mouse Ear Reveals the Immediate Effect of Anti-CD3 Treatment in Autoimmune Diabetes.
Benson RA, Garcon F, Recino A, Ferdinand JR, Clatworthy MR, Waldmann H, Brewer JM, Okkenhaug K, Cooke A, Garside P, Wållberg M

We present a novel and readily accessible method facilitating cellular time-resolved imaging of transplanted pancreatic islets. Grafting of islets to the mouse ear pinna allows non-invasive, longitudinal imaging of events in the islets and enables improved acquisition of experimental data and use of fewer experimental animals than is possible using invasive techniques, as the same mouse can be assessed for the presence of islet infiltrating cells before and after immune intervention. We have applied this method to investigating therapeutic protection of beta cells through the well-established use of anti-CD3 injection, and have acquired unprecedented data on the nature and rapidity of the effect on the islet infiltrating T cells. We demonstrate that infusion of anti-CD3 antibody leads to immediate effects on islet infiltrating T cells in islet grafts in the pinna of the ear, and causes them to increase their speed and displacement within 20 min of infusion. This technique overcomes several technical challenges associated with intravital imaging of pancreatic immune responses and facilitates routine study of beta islet cell development, differentiation, and function in health and disease.

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Frontiers in immunology, 9, 1664-3224, 1006, 2018

PMID: 29867981


Open Access

Flotillin proteins recruit sphingosine to membranes and maintain cellular sphingosine-1-phosphate levels.
Riento K, Zhang Q, Clark J, Begum F, Stephens E, Wakelam MJ, Nichols BJ

Sphingosine-1-phosphate (S1P) is an important lipid signalling molecule. S1P is produced via intracellular phosphorylation of sphingosine (Sph). As a lipid with a single fatty alkyl chain, Sph may diffuse rapidly between cellular membranes and through the aqueous phase. Here, we show that the absence of microdomains generated by multimeric assemblies of flotillin proteins results in reduced S1P levels. Cellular phenotypes of flotillin knockout mice, including changes in histone acetylation and expression of Isg15, are recapitulated when S1P synthesis is perturbed. Flotillins bind to Sph in vitro and increase recruitment of Sph to membranes in cells. Ectopic re-localisation of flotillins within the cell causes concomitant redistribution of Sph. The data suggest that flotillins may directly or indirectly regulate cellular sphingolipid distribution and signalling.

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PloS one, 13, 1932-6203, e0197401, 2018

PMID: 29787576


Open Access

The reference epigenome and regulatory chromatin landscape of chronic lymphocytic leukemia.
Beekman R, Chapaprieta V, Russiñol N, Vilarrasa-Blasi R, Verdaguer-Dot N, Martens JHA, Duran-Ferrer M, Kulis M, Serra F, Javierre BM, Wingett SW, Clot G, Queirós AC, Castellano G, Blanc J, Gut M, Merkel A, Heath S, Vlasova A, Ullrich S, Palumbo E, Enjuanes A, Martín-García D, Beà S, Pinyol M, Aymerich M, Royo R, Puiggros M, Torrents D, Datta A, Lowy E, Kostadima M, Roller M, Clarke L, Flicek P, Agirre X, Prosper F, Baumann T, Delgado J, López-Guillermo A, Fraser P, Yaspo ML, Guigó R, Siebert R, Martí-Renom MA, Puente XS, López-Otín C, Gut I, Stunnenberg HG, Campo E, Martin-Subero JI

Chronic lymphocytic leukemia (CLL) is a frequent hematological neoplasm in which underlying epigenetic alterations are only partially understood. Here, we analyze the reference epigenome of seven primary CLLs and the regulatory chromatin landscape of 107 primary cases in the context of normal B cell differentiation. We identify that the CLL chromatin landscape is largely influenced by distinct dynamics during normal B cell maturation. Beyond this, we define extensive catalogues of regulatory elements de novo reprogrammed in CLL as a whole and in its major clinico-biological subtypes classified by IGHV somatic hypermutation levels. We uncover that IGHV-unmutated CLLs harbor more active and open chromatin than IGHV-mutated cases. Furthermore, we show that de novo active regions in CLL are enriched for NFAT, FOX and TCF/LEF transcription factor family binding sites. Although most genetic alterations are not associated with consistent epigenetic profiles, CLLs with MYD88 mutations and trisomy 12 show distinct chromatin configurations. Furthermore, we observe that non-coding mutations in IGHV-mutated CLLs are enriched in H3K27ac-associated regulatory elements outside accessible chromatin. Overall, this study provides an integrative portrait of the CLL epigenome, identifies extensive networks of altered regulatory elements and sheds light on the relationship between the genetic and epigenetic architecture of the disease.

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Nature medicine, , 1546-170X, , 2018

PMID: 29785028


Extracellular vesicles : lipids as key components of their biogenesis and functions.
Record M, Silvente-Poirot S, Poirot M, Wakelam MJO

Intercellular communication has been known for decades to involve either direct contact between cells or to operate by spreading molecules such as cytokines, growth factors, or lipid mediators. Through the last decade we have begun to appreciate the increasing importance of intercellular communication mediated by extracellular vesicles released by viable cells either from plasma membrane shedding microvesicles, also named microparticles), or from an intracellular compartment (exosomes). Exosomes and microvesicles circulate in all biological fluids and can trigger biological responses at distance. Their effects include a large variety of biological processes such as immune surveillance, modification of tumor microenvironment, or regulation of inflammation. They carry a large set of active molecules, including lipid mediators such as eicosanoids, proteins and nucleic acids, able to modify the phenotype of receiving cells. This review will highlight the role of the various lipidic pathways involved in the biogenesis and functions of microvesicles and exosomes.

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Journal of lipid research, , 1539-7262, , 2018

PMID: 29764923


Open Access

Allele-specific control of replication timing and genome organization during development.
Rivera-Mulia JC, Dimond A, Vera D, Trevilla-Garcia C, Sasaki T, Zimmerman J, Dupont C, Gribnau J, Fraser P, Gilbert DM

DNA replication occurs in a defined temporal order known as the replication-timing (RT) program. RT is regulated during development in discrete chromosomal units, coordinated with transcriptional activity and 3D genome organization. Here, we derived distinct cell types from F1 hybrid musculus X castaneus mouse crosses and exploited the high single nucleotide polymorphism (SNP) density to characterize allelic differences in RT (Repli-seq), genome organization (Hi-C and promoter-capture Hi-C), gene [removed]total nuclear RNA-seq) and chromatin accessibility (ATAC-seq). We also present HARP: a new computational tool for sorting SNPs in phased genomes to efficiently measure allele-specific genome-wide data. Analysis of six different hybrid mESC clones with different genomes (C57BL/6, 129/sv and CAST/Ei), parental configurations and gender revealed significant RT asynchrony between alleles across ~12% of the autosomal genome linked to sub-species genomes but not to parental origin, growth conditions or gender. RT asynchrony in mESCs strongly correlated with changes in Hi-C compartments between alleles but not SNP density, gene expression, imprinting or chromatin accessibility. We then tracked mESC RT asynchronous regions during development by analyzing differentiated cell types including extraembryonic endoderm stem (XEN) cells, 4 male and female primary mouse embryonic fibroblasts (MEFs) and neural precursor cells (NPCs) differentiated in vitro from mESCs with opposite parental configurations. We found that RT asynchrony and allelic discordance in Hi-C compartments seen in mESCs was largely lost in all differentiated cell types, coordinated with a more uniform Hi-C compartment arrangement, suggesting that genome organization of homologues converges to similar folding patterns during cell fate commitment.

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Genome research, , 1549-5469, , 2018

PMID: 29735606


Sequence-dependent attack on peptides by photoactivated platinum anticancer complexes.
Wootton CA, Sanchez-Cano C, Lopez-Clavijo AF, Shaili E, Barrow MP, Sadler PJ, O'Connor PB

Octahedral platinum(iv) complexes such as ,,-[Pt(N)(OH)(pyridine)] () are stable in the dark, but potently cytotoxic to a range of cancer cells when activated by UVA or visible light, and active . Photoactivation causes the reduction of the complex and leads to the formation of unusual Pt(ii) lesions on DNA. However, radicals are also generated in the excited state resulting from photoactivation (J. S. Butler, J. A. Woods, N. J. Farrer, M. E. Newton and P. J. Sadler, , 2012, , 16508-16511). Here we show that once photoactivated, also can interact with peptides, and therefore proteins are potential targets of this candidate drug. High resolution FT-ICR MS studies show that reactions of activated by visible light with two neuropeptides Substance P, RPKPQQFFGLM-NH () and [Lys]-Bombesin, pEQKLGNQWAVGHLM-NH () give rise to unexpected products, in the form of both oxidised and platinated peptides. Further MS/MS analysis using electron-capture dissociation (ECD) dissociation pathways (enabling retention of the Pt complex during fragmentation), and EPR experiments using the spin-trap DEPMPO, show that the products generated during the photoactivation of depend on the amino acid composition of the peptide. This work reveals the multi-targeting nature of excited state platinum anticancer complexes. Not only can they target DNA, but also peptides (and proteins) by sequence dependent platination and radical mechanisms.

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Chemical science, 9, 2041-6520, 2733-2739, 2018

PMID: 29732057


Open Access

Interaction between a MAPT variant causing frontotemporal dementia and mutant APP affects axonal transport.
Adalbert R, Milde S, Durrant C, Ando K, Stygelbout V, Yilmaz Z, Gould S, Brion JP, Coleman MP

In Alzheimer's disease, many indicators point to a central role for poor axonal transport, but the potential for stimulating axonal transport to alleviate the disease remains largely untested. Previously, we reported enhanced anterograde axonal transport of mitochondria in 8- to 11-month-old MAPT knockin mice, a genetic model of frontotemporal dementia with parkinsonism-17T. In this study, we further characterized the axonal transport of mitochondria in younger MAPT mice crossed with the familial Alzheimer's disease model, TgCRND8, aiming to test whether boosting axonal transport in young TgCRND8 mice can alleviate axonal swelling. We successfully replicated the enhancement of anterograde axonal transport in young MAPT knockin animals. Surprisingly, we found that in the presence of the amyloid precursor protein mutations, MAPT impaired anterograde axonal transport. The numbers of plaque-associated axonal swellings or amyloid plaques in TgCRND8 brains were unaltered. These findings suggest that amyloid-β promotes an action of mutant tau that impairs axonal transport. As amyloid-β levels increase with age even without amyloid precursor protein mutation, we suggest that this rise could contribute to age-related decline in frontotemporal dementia.

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Neurobiology of aging, 68, 1558-1497, 68-75, 2018

PMID: 29729423


Open Access

Defective germline reprogramming rewires the spermatogonial transcriptome.
Vasiliauskaitė L, Berrens RV, Ivanova I, Carrieri C, Reik W, Enright AJ, O'Carroll D

Defective germline reprogramming in Piwil4 (Miwi2)- and Dnmt3l-deficient mice results in the failure to reestablish transposon silencing, meiotic arrest and progressive loss of spermatogonia. Here we sought to understand the molecular basis for this spermatogonial dysfunction. Through a combination of imaging, conditional genetics and transcriptome analysis, we demonstrate that germ cell elimination in the respective mutants arises as a result of defective de novo genome methylation during reprogramming rather than because of a function for the respective factors within spermatogonia. In both Miwi2 and Dnmt3l spermatogonia, the intracisternal-A particle (IAP) family of endogenous retroviruses is derepressed, but, in contrast to meiotic cells, DNA damage is not observed. Instead, we find that unmethylated IAP promoters rewire the spermatogonial transcriptome by driving expression of neighboring genes. Finally, spermatogonial numbers, proliferation and differentiation are altered in Miwi2 and Dnmt3l mice. In summary, defective reprogramming deregulates the spermatogonial transcriptome and may underlie spermatogonial dysfunction.

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Nature structural & molecular biology, 25, 1545-9985, 394-404, 2018

PMID: 29728652


GIMAP6 is required for T cell maintenance and efficient autophagy in mice.
Pascall JC, Webb LMC, Eskelinen EL, Innocentin S, Attaf-Bouabdallah N, Butcher GW

The GTPases of the immunity-associated proteins (GIMAP) GTPases are a family of proteins expressed strongly in the adaptive immune system. We have previously reported that in human cells one member of this family, GIMAP6, interacts with the ATG8 family member GABARAPL2, and is recruited to autophagosomes upon starvation, suggesting a role for GIMAP6 in the autophagic process. To study this possibility and the function of GIMAP6 in the immune system, we have established a mouse line in which the Gimap6 gene can be inactivated by Cre-mediated recombination. In mice bred to carry the CD2Cre transgene such that the Gimap6 gene was deleted within the T and B cell lineages there was a 50-70% reduction in peripheral CD4+ and CD8+ T cells. Analysis of splenocyte-derived proteins from these mice indicated increased levels of MAP1LC3B, particularly the lipidated LC3-II form, and S405-phosphorylation of SQSTM1. Electron microscopic measurements of Gimap6-/- CD4+ T cells indicated an increased mitochondrial/cytoplasmic volume ratio and increased numbers of autophagosomes. These results are consistent with autophagic disruption in the cells. However, Gimap6-/- T cells were largely normal in character, could be effectively activated in vitro and supported T cell-dependent antibody production. Treatment in vitro of CD4+ splenocytes from GIMAP6fl/flERT2Cre mice with 4-hydroxytamoxifen resulted in the disappearance of GIMAP6 within five days. In parallel, increased phosphorylation of SQSTM1 and TBK1 was observed. These results indicate a requirement for GIMAP6 in the maintenance of a normal peripheral adaptive immune system and a significant role for the protein in normal autophagic processes. Moreover, as GIMAP6 is expressed in a cell-selective manner, this indicates the potential existence of a cell-restricted mode of autophagic regulation.

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PloS one, 13, 1932-6203, e0196504, 2018

PMID: 29718959


Open Access