Biology subjects

Roers, A.

Publications and source records attributed to Roers, A..

12 recordsLinked to original sources

bioRxiv2025

Decades-long elevation of interferon-alpha drives a Sjogren disease endotype: an interdisciplinary study

BACKGROUNDMechanistic heterogeneity is a major obstacle to the development of effective treatment for Sjogren disease (SjD) and there is a pressing need to stratify SjD according to precision medicine principles. Aberrant activation of the type I interferon (IFN) pathway represents a leading candidate pathway, but a causal role of elevated IFN- in driving a Sjogren disease endotype remains to be established. METHODSWe used ultrasensitive single molecule ELISA, and an oligoprotein interferon signature score (derived from broad capture proteomics), to study the role of IFN- in Sjogren disease. We analysed samples from the UK Primary Sjogren Syndrome Registry (UKPSSR, n=177) and UK Biobank Plasma Proteomics Project (n=47606 without Sjogren, n=257 with Sjogren, including 137 individuals sampled prior to diagnosis) to determine the timecourse and immune endotype associated with elevated IFN-. To address causality we created a new transgenic mouse model of IFN- overexpression to establish whether chronically elevated IFN- drives this immune endotype. FINDINGSOligoprotein interferon signatures can be detected at least 14 years prior to diagnosis of Sjogren disease in the UK Biobank-PPP. IFN- concentrations are elevated in 60% of Sjogren disease patients in the UKPSSR. Individuals with elevated IFN- display a distinct immunological endotype characterised by cytopenias, hypergammaglobulinaemia, multiple autoantibodies and autoimmunity against the Sjogren autoantigen TRIM21/Ro52. To address the key question of causal direction, we created a new mouse model of systemic chronic IFN- elevation, in which Ifn4 is overexpressed by conventional dendritic cells. This model recapitulates key features of the endotype and can be partially reversed by IFNAR1 blockade. INTERPRETATIONElevation of IFN- drives an immune endotype of Sjogren disease, originating over a decade prior to diagnosis. SjD patients with elevated IFN- concentrations are broadly clinically similar to those with normal IFN- concentrations, yet are immunologically distinct. This highlights the mechanistic heterogeneity of SjD and the need for immunological stratification along precision medicine principles, using high resolution biomarkers. As well as demonstrating causal direction, biological modelling shows that chronic IFN- elevation over the lifecourse has the potential to establish persistent immune dysregulation which responds only partially to interferon receptor blockade. These findings provide insights into SjD and other "interferonopathic" rheumatological disorders. Research in contextO_ST_ABSEvidence before this studyC_ST_ABSWe searched MEDLINE for "Sjogrens Syndrome/Disease" and "interferon", including the terms "subsets", "sub-groups", "phenotypes", and "endotypes", filtering by "clinical trial", "stratification", and "immune-mediated inflammatory". We also included major review articles from noted experts. We identified reports of associations between IFN- and SjD, usually using indirect or imprecise measures of IFN-. None of these studies included prediagnostic samples and causal inference was limited. Added value of this studyThis study shows that IFN-, when measured directly using ultrasensitive single molecule ELISA approaches (uniquely optimised to determine healthy control concentrations), is elevated in a subset of people with SjD with a specific immunological endotype. Analysis of prediagnostic proteomics shows this elevation can be detected up to 14 years before diagnosis. We show that IFN- drives this endotype (as opposed to vice versa) by recapitulating key endotype features in a novel and unambiguous experimental mouse model of chronic IFN- elevation. We also show that the pathogenic consequences of IFN- elevation over long periods of time can only be partially reversed using IFNAR blockade. Implications of all the available evidenceThese data have important implications for future research, clinical practice, trial design, and therapeutic development. First, our findings provide clinical evidence, supported by unambiguous preclinical evidence, that decades-long elevated IFN can cause and drive a SjD endotype - and accurately defines the level of heterogeneity. Secondly, we provide biomarkers which may be of use in stratifying clinical trial design and also for early identification of at-risk individuals. Thirdly we provide biological proof of principle that longstanding and potentially undiagnosed elevation of IFN- can establish persistent immune dysregulation which may respond only partially to IFNAR blockade. Together these findings inform precision medicine approaches and future trial design.

immunology↗

bioRxiv2024

Selective inflammation of the tumor microenvironment and invigorated T cell-mediated tumor control upon induced systemic inactivation of TREX1

Therapeutic innate immune stimulation within the tumor microenvironment can potentiate endogenous antitumor T cell immunity. DNase 3-repair exonuclease 1 (TREX1) is essential for cellular DNA disposal which prevents autoimmunity ensuing from cGAS/STING activation by endogenous DNA. Optimal strategies to therapeutically leverage cGAS/STING signalling for cancer therapy are highly sought after. TREX1-deficient tumor cells elicit enhanced protective immunity in syngeneic models. Here we show that induced inactivation of the Trex1 gene in (non-malignant) host cells is well tolerated and yields improved type I IFN- and T cell-dependent control of established TREX1-competent tumors with selective immune cell infiltration of tumor, but not other tissues. Intra-tumoral T cell proliferation and numbers of effector and effector-like exhausted cells massively increased, enabling complete rejection in synergy with checkpoint inhibition. We conclude that systemic TREX1 inhibition is a promising approach to boost anti-tumor immunity, that can overcome immune evasion by cancer cell- intrinsic cGAS/STING inactivation.

immunology↗

bioRxiv2022

Emergency hematopoiesis proceeds without contribution of hematopoietic stem cells

Hematopoietic stem cells (HSCs) are the ultimate source of blood and immune cells. Under homeostatic conditions, these cells are considered a quiescent reserve population. However, it is not clear to what extent HSCs participate in emergency responses. Herein, we use fate mapping and proliferation tracking mouse models, which cumulatively record HSC activity in situ. We observed no direct contribution of HSCs to mature blood cell regeneration in response to common hematopoietic emergencies, including inflammation or blood loss. Innate immune training, in which HSCs were proposed to store and integrate information on previous infections, did not alter HSC activity upon secondary exposure. Only severe myeloablation resulted in a robust increase of HSC contribution. Our data demonstrates that HSCs do not directly participate in the regeneration of mature blood cells and therefore do not represent a reserve population to compensate for physiological hematopoietic perturbations.

cell biology↗

bioRxiv2022

Suppression of systemic T cell immunity to viral infection during liver injury is prevented by inhibition of interferon and IL-10 signaling

Patients with liver injury such as cirrhosis are at increased risk of intractable viral infections and are hyporesponsive to vaccination. Here, we report that liver injury leads to inhibition of systemic T cell immunity (LIST), which abrogated anti-viral immunity and caused persistent infection in preclinical liver injury models. Enhanced gut microbial-translocation but not dysbiosis induced tonic type-I-interferon (IFN) signaling in hepatic myeloid cells, which was responsible for their excessive production of IL-10 after viral infection. Antibiotic treatment reducing intestinal microbial burden or inhibition of IFN- and IL-10-signaling all restored anti-viral immunity without immune pathology. Importantly, inhibition of IL-10 restored virus-specific immune responses to vaccination in cirrhotic patients. Thus, LIST results from sequential events involving intestinal microbial translocation, hepatic myeloid cell-derived IFN-/IL-10 expression, and finally inhibitory IL-10 receptor-signaling in T cells, of which IL-10R-signaling may serve as target to reconstitute anti-viral T cell immunity in cirrhotic patients.

immunology↗

bioRxiv2022

Slow integrin-dependent migration organizes networks of tissue-resident mast cells

Many leukocytes use fast and flexible amoeboid migration strategies to move autonomously throughout tissues. Here, we show that the movement of mast cells (MCs), leukocytes with important roles during allergies and anaphylaxis, fundamentally differs from this rapid adhesion-free leukocyte migration. We identify a crucial role for integrin-dependent adhesion in controlling slow MC movement, which shapes the positioning and network-like tissue distribution of this long-lived immune cell type. In contrast to other immune and non-immune cells, MCs cannot compensate for the lack of integrin function by switching to another migration mode. Single-cell RNA-sequencing revealed a special role for integrins in defining a mature MC phenotype in the periarteriolar tissue space where several stromal cell types provide an anatomical niche rich in Kit ligand, the major MC growth and survival factor. Collectively, this study highlights substrate-dependent haptokinesis as an important mechanism for MC network formation and the tissue organization of resident immune cells.

cell biology↗

bioRxiv2022

Clearance of genome-damaged cells from the hematopoietic system via p53 without contribution by the cGAS/STING axis

Cell-intrinsic response patterns control risks arising from genome-damage, preventing malignant transformation. The DNA sensor cyclic-GMP-AMP synthase (cGAS) has emerged as a new principle detecting genome damage, as it can be triggered by aberrant self-DNA. Stimulator of interferon genes (STING)-activation downstream of cGAS can drive cells into senescence or cell death and induces antiproliferative type I interferon (IFN) and pro-apoptotic tumor necrosis factor responses. Herein, we investigated how DNA damage-driven activation of cGAS/STING signaling impacts on hematopoiesis. Defective ribonucleotide excision repair (RER) in the hematopoietic system caused chromosomal instability as well as robust activation of the cGAS/STING/IFN axis, and compromised hematopoietic stem cell function, resulting in cytopenia and ultimately leukemia. Whereas loss of p53 largely rescued RER-deficient hematopoiesis at the cost of further accelerated leukemogenesis, the additional inactivation of cGAS, STING or type I IFN signaling had no detectable effect on blood cell generation and leukemia development. Moreover, cGAS-deficient hematopoiesis showed unaltered responses to spontaneous or acute DNA damage. Our data demonstrate that the cGAS/STING pathway is dispensable for the hematopoietic system coping with chronic or acute DNA damage and does not protect against leukemic transformation in the absence of RER.

cell biology↗

bioRxiv2022

Validation of an RNase H2 activity assay suitable for clinical screening

As the key enzyme mediating ribonucleotide excision repair, RNase H2 is essential for the removal of single ribonucleotides from DNA in order to prevent genome damage. Loss of RNase H2 activity directly contributes to the pathogenesis of autoinflammatory and autoimmune diseases and might further play a role in ageing and neurodegeneration. Moreover, RNase H2 activity is a potential diagnostic and prognostic marker in several types of cancer. Until today, no method for quantification of RNase H2 activity has been validated for the clinical setting. Herein, validation and benchmarks of a FRET-based whole-cell lysate RNase H2 activity assay are presented, including standard conditions and procedures to calculate standardized RNase H2 activity. Spanning a wide working range, the assay is applicable to various human cell or tissue samples with overall methodological assay variability from 8.6% to 16%. The assay readily detected reduced RNase H2 activity in lymphocytes of a patient with systemic sclerosis carrying a RNASEH2C variant. Implementation of larger control groups will help to assess the diagnostic and prognostic value of clinical screening for RNase H2 activity in the future.

immunology↗

bioRxiv2022

cGAS/STING-DEPENDENT SENSING OF ENDOGENOUS RNA

Defects in nucleic acid metabolizing enzymes lead to spontaneous but selective activation of either cGAS/STING or RIG-like receptor (RLR) signaling, causing a pathogenic type I interferon response and inflammatory diseases. In these pathophysiological conditions, cGAS-driven IFN production is linked to spontaneous DNA damage. Physiological, or tonic, IFN signaling on the other hand is essential to functionally prime nucleic acid sensing pathways. Here we show that low-level chronic DNA damage in mice lacking the Aicardi-Goutieres syndrome gene SAMHD1 reduced tumor-free survival when crossed to a p53-deficient, but not to DNA mismatch repair-deficient background. Increased DNA damage did not result in higher levels of type I interferon. Instead, we found that the chronic interferon response in SAMHD1-deficient mice was driven by the MDA5/MAVS pathway but required functional priming through the cGAS/STING pathway. Our work positions cGAS/STING upstream of tonic IFN signaling and highlights an important role of the pathway in physiological and pathophysiological innate immune priming. SummaryLoss of the dNTPase and DNA repair enzyme SAMHD1 is associated with cancer and causes systemic autoimmunity. We show transformation-promoting spontaneous DNA damage and MDA5-driven but cGAS/STING-dependent chronic type I interferon production in SAMHD1-deficient mice.

immunology↗

bioRxiv2021

Predictive framework of macrophage activation

Macrophages populate every organ during homeostasis and disease, displaying features of tissue imprinting and heterogeneous activation. The disjointed picture of macrophage biology that emerged from these observations are a barrier for integration across models or with in vitro macrophage activation paradigms. We set out to contextualize macrophage heterogeneity across mouse tissues and inflammatory conditions, specifically aiming to define a common framework of macrophage activation. We built a predictive model with which we mapped the activation of macrophages across 12 tissues and 25 biological conditions, finding a striking commonality and finite number of transcriptional profiles, which we modelled as defined stages along four conserved activation paths. We verified this model with adoptive cell transfer experiments and identified transient RELM[a] expression as a feature of macrophage tissue engraftment. We propose that this integrative approach of macrophage classification allows the establishment of a common predictive framework of macrophage activation in inflammation and homeostasis. One Sentence SummaryWe propose an integrative approach of macrophage classification that allows the establishment of a common framework of macrophage activation in inflammation and homeostasis.

immunology↗

bioRxiv2020

Filaggrin deficient mice have a lower threshold for cutaneous allergen sensitization but do not develop spontaneous skin inflammation or atopy

Defects of filaggrin (FLG) compromise epidermal barrier function and represent an important known genetic risk factor for atopic dermatitis (AD), but also for systemic atopy, including allergic sensitization and asthma. The flaky tail mouse model, widely used to address mechanisms of atopy induction by barrier-defective skin, harbors two mutations that affect the skin barrier, the mutation Flgft, resulting in near-complete loss of FLG expression, and the matted mutation inactivating transmembrane protein 79 (Tmem79). Upon separation of the two mutant loci, which are closely linked on chromosome 3, mice defective only for Tmem79 featured pronounced dermatitis and systemic atopy. Upon extensive backcross to BALB/c, also Flgft/ft mice (assumed to be wild type for Tmem79), developed AD-like dermatitis and reproduced the human atopic march, with high IgE levels and spontaneous asthma, suggesting a key role for functional Flg in protection from atopy also in mice. In contrast, BALB/c mice congenic for a targeted Flg knock out mutation did not develop skin inflammation or atopy. To resolve this discrepancy, we generated Flg-deficient mice on a pure BALB/c background by inactivating the Flg gene in BALB/c embryos. These animals feature an ichthyosis phenotype, but do not develop spontaneous dermatitis or systemic atopy. We sequenced the genome of the atopic Flgft BALB/c congenics and discovered that they were unexpectedly homozygous for the atopy-causing Tmem79matted mutation. In summary, we show that Flg-deficiency does not cause atopy in mice. This finding is in line with lack of atopic disease in a fraction of Ichthyosis vulgaris patients carrying two FLG null alleles. However, absence of FLG may promote and modulate dermatitis caused by other genetic barrier defects, as skin inflammation in Tmem79ma/maFlgft/ft BALB/c congenics is qualitatively different compared to Tmem79ma/ma mice.

immunology↗

bioRxiv2020

Hematopoietic lineages diverge within the stem cell compartment

Hematopoietic stem cells (HSCs) produce a highly diverse array of cell lineages. To assay hematopoietic differentiation with minimal experimental perturbation, non-invasive methods for heritable labeling1-3 or barcoding4-7 of HSCs in vivo have recently been developed and used to study lineage fate of HSCs in physiological conditions. However, the differentiation pathways leading from HSCs to mature cells remain controversial8, with suggested models ranging from gradual lineage restriction in a branching cascade of progenitors to HSCs already making ultimate lineage decisions. Here we show, by iterating HSC fate-mapping, mitotic history tracking, single-cell RNA-sequencing and computational inference, that the major differentiation routes to megakaryocytes, erythro-myeloid cells and lymphocytes split within HSCs. We identify the hitherto elusive self-renewing source of physiological hematopoiesis as an HSC subpopulation co-expressing high levels of Sca-1 and CD201. Downstream, HSCs reduce Sca-1 expression and enter into either thrombopoiesis or erythro-myelopoiesis, or retain high Sca-1 levels and the ability to generate lymphocytes. Moreover, we show that a distinct population of CD48-/lo megakaryocyte progenitors links HSCs to megakaryocytes. This direct thrombopoiesis pathway is independent of the classical pathway of megakaryocyte differentiation via multipotent progenitors and becomes the dominant platelet production line upon enhanced thrombopoietin signaling. Our results define a hierarchy of self-renewal and lineage decisions within HSCs in native hematopoiesis. Methodologically, we provide a blueprint for mapping physiological differentiation pathways of stem cells and probing their regulation.

systems biology↗

bioRxiv2019

Proliferative behavior of hematopoietic stem cells revisited: No evidence for mitotic memory

The proliferative activity of adult hematopoietic stem cells (HSCs) is controversially discussed. Inducible fluorescent histone 2B fusion protein (H2B-FP) transgenic mice are important tools for tracking the mitotic history of murine HSCs in label dilution experiments. A recent study proposed that the most primitive HSCs divide only four times, to then enter permanent quiescence. We observed that background fluorescence due to leaky H2B-FP expression, occurring in all H2B-FP transgenes independent of label induction, accumulated with age in primitive HSCs with high repopulation potential. We argue that this background had been misinterpreted as retention of induced label and permanent quiescence. We found cell division-independent half-lives of H2B-FPs to be short, which had led to overestimation of HSC divisional activity. Our data do not support HSC mitotic memory and entry into permanent quiescence after few divisions, but show that primitive HSCs of adult mice continue to cycle rarely.\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC=\"FIGDIR/small/745729v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (30K):\norg.highwire.dtl.DTLVardef@1b97626org.highwire.dtl.DTLVardef@fbc702org.highwire.dtl.DTLVardef@1c66b60org.highwire.dtl.DTLVardef@1b38f69_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗