Publications by authors named "Martina Braun"

Article Synopsis
  • Epigenetic heterogeneity plays a key role in how biological systems function and can influence tumor behavior and resistance to treatments.
  • The authors introduce a new tool called epiCHAOS, which measures variations in epigenetic traits between individual cells, regardless of their grouping.
  • After testing its effectiveness on simulated data, epiCHAOS is shown to reveal important insights into developmental and cancer-related characteristics, enhancing our understanding of single-cell epigenomics in these contexts.
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Single-cell bisulfite sequencing (scBS) is a technique that enables the assessment of DNA methylation at single-base pair and single-cell resolution. The analysis of large datasets obtained from scBS requires preprocessing to reduce the data size, improve the signal-to-noise ratio and provide interpretability. Typically, this is achieved by dividing the genome into large tiles and averaging the methylation signals within each tile.

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Current approaches to lineage tracing of stem cell clones require genetic engineering or rely on sparse somatic DNA variants, which are difficult to capture at single-cell resolution. Here, we show that targeted single-cell measurements of DNA methylation at single-CpG resolution deliver joint information about cellular differentiation state and clonal identities. We develop EPI-clone, a droplet-based method for transgene-free lineage tracing, and apply it to study hematopoiesis, capturing hundreds of clonal trajectories across almost 100,000 single-cells.

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Objective: To analyze the ability to evaluate changes over time of individual lesions of incomplete or complete retinal pigment epithelium (RPE) and outer retinal atrophy (iRORA and cRORA, respectively) in patients with intermediate age-related macular degeneration (iAMD).

Design: OCT images from patients enrolled in Proxima B clinical trial (NCT02399072) were utilized.

Participants: Patients enrolled in the Proxima B clinical trial, from the cohort with geographic atrophy (GA) in 1 eye and iAMD in the other eye at baseline, were included.

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In the present work, we aim at developing an in vitro release assay to predict circulation times of hydrophobic drugs loaded into polymeric micelles (PM), upon intravenous (i.v.) administration.

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Introduction: This retrospective analysis assessed geographic atrophy (GA) progression in fellow eyes from the Proxima B trial intermediate age-related macular degeneration (iAMD) subcohort using high-resolution multimodal imaging anchored on optical coherence tomography (OCT).

Methods: Thirty-two patients from the Proxima B iAMD subcohort were assessed; all had GA with no macular neovascularization (MNV) in the contralateral eye. Imaging data, including color fundus photography, fluorescein angiography, near-infrared reflectance, fundus autofluorescence (FAF), and spectral-domain OCT, were obtained.

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Clinical evidence suggests alterations in receptor activator of NF-κB (RANK) signaling are key contributors to B cell autoimmunity and malignancy, but the pathophysiological consequences of aberrant B cell-intrinsic RANK signaling remain unknown. We generated mice that express a human lymphoma-derived, hyperactive RANKK240E variant in B lymphocytes in vivo. Forced RANK signaling disrupted B cell tolerance and induced a fully penetrant systemic lupus erythematosus-like disease in addition to the development of chronic lymphocytic leukemia (CLL).

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Acute myeloid leukemia (AML) represents the most common acute leukemia among adults. Despite recent progress in diagnosis and treatment, long-term outcome remains unsatisfactory. The success of allogeneic stem cell transplantation underscores the immunoresponsive nature of AML, creating the basis for further exploiting immunotherapies.

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Acute myeloid leukemia (AML) is the most common acute leukemia amongst adults with a 5-year overall survival lower than 30%. Emerging evidence suggest that immune alterations favor leukemogenesis and/or AML relapse thereby negatively impacting disease outcome. Over the last years myeloid derived suppressor cells (MDSCs) have been gaining momentum in the field of cancer research.

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It is well established that the stromal niche exerts a protective effect on chronic lymphocytic leukemia (CLL) cells, thereby also affecting their drug sensitivity. One hallmark of malignant cells is metabolic reprogramming, which is mostly represented by a glycolytic shift known as the Warburg effect. Because treatment resistance can be linked to metabolic alterations, we investigated whether bone marrow stromal cells impact the bioenergetics of primary CLL cells.

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Molecular models of cell fate specification typically focus on the activation of specific lineage programs. However, the concurrent repression of unwanted transcriptional networks is also essential to stabilize certain cellular identities, as shown in a number of diverse systems and phyla. Here, we demonstrate that this dual requirement also holds true in the context of Drosophila myogenesis.

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Myeloid-derived suppressor cells (MDSCs) represent a heterogeneous population that shares certain characteristics including an aberrant myeloid phenotype and the ability to suppress T cells. MDSCs have been predominantly studied in malignant diseases and findings suggest involvement in tumor-associated immune suppression. Chronic lymphocytic leukemia (CLL) is the leukemia with the highest incidence among adults.

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Genomic structural variation (SV) is a major determinant for phenotypic variation. Although it has been extensively studied in humans, the nucleotide resolution structure of SVs within the widely used model organism Drosophila remains unknown. We report a highly accurate, densely validated map of unbalanced SVs comprising 8962 deletions and 916 tandem duplications in 39 lines derived from short-read DNA sequencing in a natural population (the "Drosophila melanogaster Genetic Reference Panel," DGRP).

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Cell fate decisions are driven through the integration of inductive signals and tissue-specific transcription factors (TFs), although the details on how this information converges in cis remain unclear. Here, we demonstrate that the five genetic components essential for cardiac specification in Drosophila, including the effectors of Wg and Dpp signaling, act as a collective unit to cooperatively regulate heart enhancer activity, both in vivo and in vitro. Their combinatorial binding does not require any specific motif orientation or spacing, suggesting an alternative mode of enhancer function whereby cooperative activity occurs with extensive motif flexibility.

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Development requires the establishment of precise patterns of gene expression, which are primarily controlled by transcription factors binding to cis-regulatory modules. Although transcription factor occupancy can now be identified at genome-wide scales, decoding this regulatory landscape remains a daunting challenge. Here we used a novel approach to predict spatio-temporal cis-regulatory activity based only on in vivo transcription factor binding and enhancer activity data.

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Smooth muscle plays a prominent role in many fundamental processes and diseases, yet our understanding of the transcriptional network regulating its development is very limited. The FoxF transcription factors are essential for visceral smooth muscle development in diverse species, although their direct regulatory role remains elusive. We present a transcriptional map of Biniou (a FoxF transcription factor) and Bagpipe (an Nkx factor) activity, as a first step to deciphering the developmental program regulating Drosophila visceral muscle development.

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Background: The shape of a nucleus depends on the nuclear lamina, which is tightly associated with the inner nuclear membrane and on the interaction with the cytoskeleton. However, the mechanism connecting the differentiation state of a cell to the shape changes of its nucleus are not well understood. We investigated this question in early Drosophila embryos, where the nuclear shape changes from spherical to ellipsoidal together with a 2.

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Background: The observation of multiple genetic markers in situ by optical microscopy and their relevance to the study of three-dimensional (3D) chromosomal organization in the nucleus have been greatly developed in the last decade. These methods are important in cancer research because cancer is characterized by multiple alterations that affect the modulation of gene expression and the stability of the genome. It is, therefore, essential to analyze the 3D genome organization of the interphase nucleus in both normal and cancer cells.

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