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Schuelke, M.

Publications and source records attributed to Schuelke, M..

8 recordsLinked to original sources

Quantification of the effects of single nucleotide variants in NKX2.1 transcription factor binding sites

Transcription factors recognise and bind specific DNA sequence patterns in promoters and enhancers thereby regulating gene expression. Variations in the DNA sequence of transcription factor binding sites (TFBSs) can alter gene regulation and may disrupt development. The transcription factor NKX2.1 is a crucial regulator of thyroid, lung, and neural development. Mutations in its coding gene NKX2-1 may cause choreoathetosis and congenital hypothyroidism with or without pulmonary dysfunction (CAHTP, OMIM #610978). Most genetically solved patients carry mutations in the coding regions of NKX2-1 that affect DNA binding, while the majority of patients with CAHTP-like symptoms do not carry mutations in the NKX2-1 coding sequence. We hypothesise that variations in the DNA-sequence at promoter or enhancer sites to which the transcription factor NKX2.1 binds could cause disease as well. We employed EMSA-seq to quantify the effects of genetic variation on NKX2.1 binding strength and used this data to train neural network models to forecast the influence of DNA variation on NKX2.1 binding. We validated our models using microscale thermophoresis, X-ray crystallography, and publicly available ChIP-seq data sets. The neural networks were able to detect TFBSs in ChIP-seq data and can thus be used to evaluate whole genome sequencing data of CAHTP-patients in order to prioritise potential disease-causing variants in regulatory elements. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=80 SRC="FIGDIR/small/708450v2_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@167cedeorg.highwire.dtl.DTLVardef@3e5291org.highwire.dtl.DTLVardef@19eb7f9org.highwire.dtl.DTLVardef@1404057_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

circVDJ-seq for T cell clonotype detection in single-cell and spatial multi-omics

Monitoring T cell repertoires in human tissues provides important insights into immune response mechanisms in cancer, infectious diseases, and autoimmunity. However, retrieving VDJ information from single-cell and spatial transcriptomics workflows with 3-barcoding of cDNA remains resource-intensive or requires specialized sequencing equipment. Here, we introduce circVDJ-seq for simplified and cost-efficient T cell receptor (TCR) profiling from 3-directed workflows like single-cell or single-nucleus RNA sequencing, ATAC+RNA multi-omics, and spatial transcriptomics. Application of circVDJ-seq to freshly resected neuroblastomas and postmortem lymph nodes affected by pneumonia or COVID-19 reveals distinct immune microenvironments and T cell clonality patterns, highlighting broad utility across diverse clinical contexts.

genomics↗

Deep learning-driven neuromorphogenesis screenings identify repurposable drugs for mitochondrial disease

Mitochondrial disease encompasses untreatable conditions affecting tissues with high energy demands. A severe manifestation of mitochondrial disease is Leigh syndrome (Leigh), which causes defects in basal ganglia and midbrain regions, psychomotor regression, lactic acidosis, and early death. We previously generated isogenic pairs of Leigh cerebral organoids and uncovered defects in neuromorphogenesis. Here, we leveraged on this disease feature to devise drug discovery pipelines. We developed a deep learning algorithm tailored for cell type-specific drug repurposing to identify drugs capable of promoting neuronal commitment. In parallel, we performed a survival drug screen in yeast and validated the repurposable hits on branching capacity in Leigh neurons. The two approaches independently highlighted azole compounds, Talarozole and Sertaconazole, both of which lowered lactate release and improved neurogenesis and neurite organization in Leigh midbrain organoids. Hence, targeting neuromorphogenesis has led to identify potential new drugs for mitochondrial disease and could prove an effective strategy for further drug discovery.

neuroscience↗

RNA-sequencing reveals strong predominance of THRA splicing isoform 2 in the developing and adult human brain

Thyroid hormone receptor alpha (THR) is a nuclear hormone receptor that binds triiodothyronine (T3) and acts as an important transcription factor in development, metabolism and reproduction. THR has in mammals two major splicing isoforms, THR1 and THR2. The better characterized isoform, THR1, is a transcriptional stimulator of genes involved in cell metabolism and growth. The less well characterized isoform, THR2, lacks the Ligand Binding Domain (LBD) and is thought to act as an inhibitor of THR1 action. The ratio of THR1 to THR2 splicing isoforms is therefore critical for transcriptional regulation in different tissues and during development. However, the expression patterns of both isoforms have not been studied in healthy human tissues or in the developing brain. Given the lack of commercially available isoform-specific antibodies, we addressed this question by analyzing four bulk RNA-sequencing datasets and two scRNA-sequencing datasets to determine the RNA expression levels of human THRA1 and THRA2 transcripts in healthy adult tissues and in the developing brain. We demonstrate how 10X Chromium scRNA-seq datasets can be used to perform splicing-sensitive analyses of isoforms that differ at the 3-end. In all datasets, we discovered a strong predominance of THRA2 transcripts at all investigated stages of human brain development and in the central nervous system from healthy human adults.

genetics↗

SURF1 mutations causative of Leigh syndrome impair human neurogenesis

Mutations in the mitochondrial complex IV assembly factor SURF1 represent a major cause of Leigh syndrome (LS), a rare fatal neurological disorder. SURF1-deficient animals have failed to recapitulate the neuronal pathology of human LS, hindering our understanding of the disease mechanisms. We generated induced pluripotent stem cells from LS patients carrying homozygous SURF1 mutations (SURF1 iPS) and performed biallelic correction via CRISPR/Cas9. In contrast to corrected cells, SURF1 iPS showed impaired neuronal differentiation. Aberrant bioenergetics in SURF1 iPS occurred already in neural progenitor cells (NPCs), disrupting their neurogenic potency. Cerebral organoids from SURF1 iPS were smaller and recapitulated the neurogenesis defects. Our data imply that SURF1 mutations cause a failure in the development of maturing neurons. Using NPC function as an interventional target, we identified SURF1 gene augmentation as a potential strategy for restoring neurogenesis in LS patients carrying SURF1 mutations.

neuroscience↗

Hybrid genome assembly and annotation of Danionella translucida, a transparent fish with the smallest known vertebrate brain

Studying the activity of distributed neuronal circuits at a cellular resolution in vertebrates is very challenging due to the size and optical turbidity of their brains. We recently presented Danionella translucida, a close relative of zebrafish, as a model organism suited for studying large-scale neural network interactions in adult individuals. Danionella remains transparent throughout its life, has the smallest known vertebrate brain and possesses a rich repertoire of complex behaviours. Here we sequenced, assembled and annotated the Danionella translucida genome employing a hybrid Illumina/Nanopore read library as well as RNA-seq of embryonic, larval and adult mRNA. We achieved high assembly continuity using low-coverage long-read data and annotated a large fraction of the transcriptome. This dataset will pave the way for molecular research and targeted genetic manipulation of the smallest known vertebrate brain.

genomics↗

Phenotero: annotate as you write

Controlled vocabularies and ontologies have become a valuable resource for knowledge representation, data integration, and downstream analyses in the biomedical domain. In precision medicine, especially in clinical genetics, the Human Phenotype Ontology (HPO) as well as disease ontologies like the Orphanet Rare Disease Ontology (ORDO) or Medical Subject Headings (MeSH) are often used for deep phenotyping of patients and coding of clinical diagnoses. However, the process of assigning ontology classes (annotating) to patient descriptions is often disconnected from the process of writing patient reports or manuscripts in word processing software such as Microsoft Word or LibreOffice. This additional workload and the requirement to install dedicated software may discourage usage of ontologies for parts of the target audience.\n\nTo improve this situation, we present Phenotero, a freely available and simple solution to annotate patient phenotypes and diseases at the time of writing clinical reports or manuscripts. We adopt Zotero, a well-established, actively developed citation management software to generate a tool which allows to reference classes from ontologies within clinical reports or manuscripts at the time of writing. We expect this approach to decrease the additional workload to a minimum while ensuring high quality associations with ontology classes. Standardised collection of phenotypic information at the time of describing the patient allows for streamlining of clinic workflow, efficient data entry, and will subsequently promote clinical and molecular diagnosis, remove ambiguousness from manuscripts, and allow sharing of anonymised patient phenotype data with ultimate goal of a better understanding of the disease. Thus, we hope that our integrated approach will further promote the usage of ontologies and controlled vocabularies in the clinical setting and in the biomedical domain.

bioinformatics↗

Mutant Plasticity Related Gene 1 (PRG1) acts as a potential modifier in SCN1A related epilepsy

Plasticity related gene 1 encodes a cerebral neuron-specific synaptic transmembrane protein that modulates hippocampal excitatory transmission on glutamatergic neurons. In mice, homozygous Prg1-deficiency results in juvenile epilepsy. Screening a cohort of 18 patients with infantile spasms (West syndrome), we identified one patient with a heterozygous mutation in the highly conserved third extracellular phosphatase domain (p.T299S). The functional relevance of this mutation was verified by in-utero electroporation of a mutant Prg1 construct into neurons of Prg1-knockout embryos, and the subsequent inability of hippocampal neurons to rescue the knockout phenotype on the single cell level. Whole exome sequencing revealed the index patient to additionally harbor a novel heterozygous SCN1A variant (p.N541S) that was inherited from her healthy mother. Only the affected child carried both heterozygous PRG1 and SCN1A mutations. The aggravating effect of Prg1-haploinsufficiency on the epileptic phenotype was verified using the kainate-model of epilepsy. Double heterozygous Prg1-/+|Scn1awt/p.R1648Hmice exhibited higher seizure susceptibility than either wildtype, Prg1-/+, or Scn1awt/p.R1648H littermates. Our study provides evidence that PRG1-mutations have a potential modifying influence on SCN1A-related epilepsy in humans.

neuroscience↗