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Biology subjects

Laugsch, M.

Publications and source records attributed to Laugsch, M..

6 recordsLinked to original sources

Time-resolved inference of gene regulatory networks underlying human cranial neural crest development suggests novel risk genes for orofacial clefting.

Cranial neural crest cells (CNCCs) play a central role in shaping the human head and face. Aberrant CNCC differentiation contributes to craniofacial birth defects, particularly non-syndromic cleft lip with or without cleft palate (nsCL/P), one of the most common congenital disorders. Although the number of genetic variants associated with this condition is steadily increasing, it remains challenging to determine if and how these variants may contribute to disease development. The majority of these variants lie within non-coding regulatory elements that govern cell-type and stage-specific gene expression, which is orchestrated by dynamic gene regulatory networks (GRNs). Despite extensive work in model organisms, a time-resolved, multi-omics perspective of GRNs controlling CNCC differentiation in a human system is still lacking. To fill this gap, we generated paired transcriptomic and chromatin accessibility data at four timepoints during in vitro differentiation of CNCCs derived from human induced pluripotent stem cells. Integrating these two modalities enabled time-resolved inference of GRNs and identification of dynamic regulatory relationships, including stage-specific roles of core transcription factors. Leveraging these time-resolved GRNs, we mapped 29 nsCL/P associated variants linked to 70 putative target genes, with 40 located outside the associated genomic loci, suggesting novel distal regulatory relationships. Integration of these data with complementary time-course scRNA-seq data revealed an ectomesenchymal-biased subpopulation of CNCCs as particularly sensitive to genetic variants associated with nsCL/P. We provide a time-resolved inference of GRN in human CNCC differentiation, allowing us to determine the dynamics of stage-specific core regulatory programs that are otherwise missed in analyses based on a single time snapshot. To our knowledge, the data represent the first multi-omics map of human CNCC with temporal resolution, which expands the understanding of early human craniofacial development, refines variant-to-gene assignment, prioritizes candidate risk genes and cell states relevant to nsCL/P. Our findings demonstrate the relevance of studying the dynamics upon differentiation rather than just one fixed timepoint and offer a valuable basis for further investigation of non-coding variation in CNCC-related disorders.

bioinformatics↗

Multi-omics profiling reveals MAGEL2-driven defects in human corticogenesis shared across Prader-Willi and Schaaf-Yang syndromes.

The human cortex acquires its advanced cognitive capacity through tightly regulated developmental programs, disruption of which underlies neurodevelopmental disorders such as Schaaf-Yang syndrome (SYS) and Prader-Willi syndrome (PWS). While SYS results from pathogenic variants in the imprinted gene MAGEL2, PWS arises from chromosomal deletions, imprinting defects or uniparental disomy encompassing the MAGEL2 locus. However, the contribution of MAGEL2 to disease pathogenesis and human corticogenesis is not fully understood. Here, we performed integrated transcriptomic, proteomic, and ubiquitinomic profiling of cortical neurons derived from CRISPR/Cas9-engineered isogenic human pluripotent stem cells (hiPSC) modeling SYS and PWS. Beyond PWS-specific signatures including dysregulated ribosomal processes, we identified MAGEL2-dependent defects shared across both disorders. These include reduced progenitor proliferation, accelerated neuronal maturation, impaired migration and adhesion, as well as abnormal synaptic development, collectively linking PWS and SYS at the level of cortical development. Notably, these phenotypes partially overlap with those observed in other neurodevelopmental disorders, suggesting that MAGEL2 governs core pathways broadly vulnerable in disease. Together, our findings establish MAGEL2 as a key regulator of human cortical development, provide a unifying mechanistic framework for SYS and PWS, accessible via a web-based platform.

neuroscience↗

Unravelling the conundrum of nucleolar NR2F1 localization: A comparative analysis of NR2F1 antibody-based approaches in vitro and in vivo.

As a transcription factor, NR2F1 regulates spatiotemporal gene expression during development and in adulthood. Aberrant NR2F1 causes a rare neurodevelopmental disorder known as Bosch-Boonstra- Schaaf Optic Atrophy Syndrome. In addition, altered NR2F1 expression is frequently observed in various cancers and is considered a prognostic marker or potential therapeutic target. In this context, NR2F1 has been shown to localize not only in the nucleus but also in the nucleoli, suggesting a novel non-canonical role in this compartment. Hence, we studied this phenomenon employing various in vitro and in vivo models in different antibody-dependent approaches. Examination of seven commonly used anti-NR2F1 antibodies in different human cancer and stem cells as well as in wild type and null mice revealed that the nucleolar localization of NR2F1 is artificial and does not play a functional role. Our subsequent comparative analysis demonstrated for the first time which anti-NR2F1 antibody best fits which approach. As our data allow for correct data interpretation, making them publicly available may have far-reaching implications for NR2F1 research in health and disease. More generally, the study also underlines the need to optimize any antibody-mediated technique.

cell biology↗

Enhancer priming by H3K4 methylation safeguards germline competence

Germline specification in mammals occurs through an inductive process whereby competent cells in the post-implantation epiblast differentiate into primordial germ cells (PGC). The intrinsic factors that endow epiblast cells with the competence to respond to germline inductive signals remain unknown. Single-cell RNA sequencing across multiple stages of an in vitro PGC-like cells (PGCLC) differentiation system shows that PGCLC genes initially expressed in the naive pluripotent stage become homogeneously dismantled in germline competent epiblast like-cells (EpiLC). In contrast, the decommissioning of enhancers associated with these germline genes is incomplete. Namely, a subset of these enhancers partly retain H3K4me1, accumulate less heterochromatic marks and remain accessible and responsive to transcriptional activators. Subsequently, as in vitro germline competence is lost, these enhancers get further decommissioned and lose their responsiveness to transcriptional activators. Importantly, using H3K4me1 deficient cells, we show that the loss of this histone modification reduces the germline competence of EpiLC and decreases PGCLC differentiation efficiency. Our work suggests that, although H3K4me1 might not be essential for enhancer function, it can facilitate the (re)activation of enhancers and the establishment of gene expression programs during specific developmental transitions.

genomics↗

Overarching control of autophagy and DNA damage response by CHD6 revealed by modeling a rare human pathology

Members of the chromodomain-helicase-DNA binding (CHD) protein family are chromatin remodelers critically implicated in human pathologies, with CHD6 being one of its least studied members. Here, we discovered a de novo CHD6 missense mutation in a patient clinically presenting the rare Hallermann-Streiff syndrome (HSS). We used genome editing to generate isogenic iPSC lines and model HSS in relevant cell types. We show that CHD6 binds a cohort of autophagy and stress response genes across cell types. The HSS-mutation affects CHD6 protein folding and impairs its ability to recruit co-factors in response to DNA damage or autophagy stimulation. This leads to an accumulation of DNA damage burden and to senescence-like phenotypes. By combining genomics and functional assays, we describe for the first time a molecular mechanism for the chromatin control of autophagic flux and genotoxic stress surveillance that applies broadly to human cell types and explains HSS onset.

cell biology↗

7q11.23 Syndromes Reveal BAZ1B as a Master Regulator of the Modern Human Face and Validate the Self-Domestication Hypothesis

Symmetrical 7q11.23 dosage alterations cause craniofacial and cognitive/behavioral phenotypes that provide a privileged entry point into the evolution of the modern human face and (pro-) sociality. We undertook a functional dissection of chromatin remodeler BAZ1B in neural crest stem cells (NCSCs) from a uniquely informative cohort of typical and atypical patients harboring 7q11.23 Copy Number Variants (CNVs). Our results reveal a key contribution of BAZ1B to NCSC in vitro induction and migration, coupled with a crucial involvement in neural crest (NC)-specific transcriptional circuits and distal regulation. By intersecting our experimental data with new paleogenetic analyses comparing modern and archaic humans, we uncover a modern-specific enrichment for regulatory changes both in BAZ1B and its experimentally defined downstream targets, thereby providing the first empirical validation of the self-domestication hypothesis and positioning BAZ1B as a master regulator of the modern human face.\n\nOne Sentence SummaryBAZ1B dosage shapes the modern human face.

evolutionary biology↗