Biology subjects

Thebaud, B.

Publications and source records attributed to Thebaud, B..

4 recordsLinked to original sources

bioRxiv2025

NDUFS2 (NADH:Ubiquinone oxidoreductase core subunit S2) in Mitochondrial Electron Transport Chain Complex I is Critical to Oxygen Responsiveness of Human Ductus Arteriosus Smooth Muscle Cells

BackgroundMitochondria in ductus arteriosus smooth muscle cells (DASMCs) are oxygen sensors triggering vasoconstriction at birth; however, the oxygen sensing mechanisms are incompletely understood. Given the conserved role of mitochondrial Complex I subunit NDUFS2 in other oxygen-sensing tissues, we examined its role in DASMC oxygen sensing, comparing it to other Complex I subunits (NDUFS1 and NDUFS7) and putative O2-sensor subunits (UQCRFS1 and COX4I2). MethodsHuman DASMCs were grown in hypoxia (pO2=41mmHg). Oxygen responsiveness was assessed, measuring changes in intracellular calcium, [Ca2+]i, cell length, and mitochondrial reactive oxygen species (mROS). DASMCs were treated for 48-hours with control siRNA versus siRNA targeting NDUFS2, NDUFS1, NDUFS7, UQCRFS1, or COX4I2. qPCR and immunoblotting confirmed knockdown. 3RNA sequencing assessed transcriptional changes following siRNA. ResultsOxygen increased mitochondrial fission, [Ca2+]i, and constricted DASMCs. 48-hours post-treatment, siNDUFS2 selectively depressed oxygen-induced increase in [Ca2+]i (siControl +18.6{+/-}2.3%, siNDUFS2 +5.5{+/-}1.5%, p<0.0001), DASMC shortening (from 18.4{+/-}1.1% to 8.9{+/-}0.8%, p<0.0001), and mROS (+24{+/-}4.9% untreated, -6.6{+/-}5.4% post-siNDUFS2, p<0.0001), without altering the KCl response or depressing respiration. The mitochondrial antioxidant MitoTEMPO reduced mROS (2.9{+/-}4.5%, p=0.001) and attenuated oxygen-induced DASMC shortening (8.4{+/-}0.9%, p=0.0003). Transcriptomics revealed unique changes in mitochondrial pathways post siNDUFS2. ConclusionsNDUFS2 regulates mROS and is a mitochondrial oxygen sensor in human DASMCs. ImpactO_LIWe demonstrated a unique role of Complex I subunit NDUFS2 (NADH:Ubiquinone Oxidoreductase Core Subunit S2), amongst putative oxygen-sensing electron transport chain subunits, in the responsiveness of human ductus arteriosus (DA) smooth muscle cells (DASMCs) to oxygen. C_LIO_LINDUFS2 knockdown inhibited oxygen-induced DASMC constriction and generation of mitochondrial reactive oxygen species, at a timepoint prior to inhibition of mitochondrial respiration and without inhibition of KCl-induced constriction. C_LIO_LIWhile mitochondria are known DA oxygen sensors, this work identifies NDUFS2 as a molecular mediator of human DA oxygen sensing within the mitochondria, enhancing our understanding of a vital physiologic phenomenon and providing a novel potential therapeutic target to modulate ductal patency. C_LI

molecular biology↗

bioRxiv2021

A single-cell atlas of human fetal lung development between 14 and 19 weeks of gestation

RationaleHuman lung development has been mainly described in morphologic studies and the potential underlying molecular mechanisms were extrapolated from animal models. Therefore, there is a need to gather knowledge from native human lung tissue. In this study we describe changes at a single-cell level in human fetal lungs during the pseudoglandular stage. MethodsWe report the cellular composition, cell trajectories and cell-to-cell communication in developing human lungs with single-nuclei RNA sequencing (snRNA-seq) on 23,251 nuclei isolated from nine human fetuses with gestational ages between 14 to 19 weeks of gestation. ResultsWe identified nine different cell types, including a rare pulmonary neuroendocrine cells population. For each cell type, marker genes are reported, and selected marker genes are used for spatial validation with fluorescent RNA in situ hybridization. Enrichment and developmental trajectory analysis provide insight into molecular mechanisms and signaling pathways within individual cell clusters according to gestational age. Lastly, ligand-receptor analysis highlights determinants of cell-to-cell communication among the different cell types through the pseudoglandular stage, including general developmental pathways (NOTCH and TGFB), as well as more specific pathways involved in vasculogenesis, neurogenesis, and immune system regulation. ConclusionThese findings provide a clinically relevant background for research hypotheses generation in projects studying normal or impaired lung development and help to develop and validate surrogate models to study human lung development, such as human lung organoids. TAKE HOME MESSAGEUsing a single-cell transcriptomic approach (single-nuclei RNA sequencing), we describe here, for the first time, the cellular landscape, cell developmental trajectories, and cell-to-cell communication in the developing human lung during the pseudoglandular stage.

developmental biology↗

bioRxiv2021

Single-cell RNA sequencing-based characterization of resident lung mesenchymal stromal cells in bronchopulmonary dysplasia

Late lung development is a period of alveolar and microvascular formation, which is pivotal in ensuring sufficient and effective gas exchange. Defects in late lung development manifest in premature infants as a chronic lung disease named bronchopulmonary dysplasia (BPD). Numerous studies demonstrated the therapeutic properties of exogenous bone marrow and umbilical cord-derived mesenchymal stromal cells (MSCs) in experimental BPD. However, very little is known regarding the regenerative capacity of resident lung MSCs (L-MSCs) during normal development and in BPD. In this study we aimed to characterize the L-MSC population in homeostasis and upon injury. We used single-cell RNA sequencing (scRNA-seq) to profile in situ Ly6a+ L-MSCs in the lungs of normal and O2-exposed neonatal mice (a well-established model to mimic BPD) at three developmental timepoints (postnatal days 3, 7 and 14). Hyperoxia exposure increased the number, and altered the expression profile of L-MSCs, particularly by increasing the expression of multiple pro-inflammatory, pro-fibrotic, and anti-angiogenic genes. In order to identify potential changes induced in the L-MSCs transcriptome by storage and culture, we profiled 15,000 Ly6a+ L-MSCs after in vitro culture. We observed great differences in expression profiles of in situ and cultured L-MSCs, particularly those derived from healthy lungs. Additionally, we have identified the location of L-MSCs in the developing lung and propose Serpinf1 as a novel, culture-stable marker of L-MSCs. Finally, cell communication analysis suggests inflammatory signals from immune and endothelial cells as main drivers of hyperoxia-induced changes in L-MSCs transcriptome.

cell biology↗

bioRxiv2019

Multiplexed single-cell transcriptomic analysis of normal and impaired lung development in the mouse

During late lung development alveolar and microvascular development is finalized to enable sufficient gas exchange. Impaired late lung development manifests as bronchopulmonary dysplasia (BPD) in preterm infants. Single-cell RNA sequencing (scRNA-seq) allows for assessment of complex cellular dynamics during biological processes, such as development. Here, we use MULTI-seq to generate scRNA-seq profiles of over 66,000 cells from 36 mice during normal or impaired lung development secondary to hyperoxia. We observed dynamic populations of cells, including several rare cell types and putative progenitors. Hyperoxia exposure, which mimics the BPD phenotype, alters the composition of all cellular compartments, particularly alveolar epithelium, capillary endothelium and macrophage populations. We identified several BPD-associated signatures, including Pdgfra in fibroblasts, Activin A in capillary endothelial cells, and Csf1-Csf1r and Ccl2-Ccr2 signaling in macrophages and neutrophils. Our data provides a novel single-cell view of cellular changes associated with late lung development in health and in disease.

cell biology↗