Biology subjects

Thome, V.

Publications and source records attributed to Thome, V..

7 recordsLinked to original sources

bioRxiv2026

The Joubert syndrome protein CSPP1 is a conserved regulator of vertebrate multiciliogenesis and motile cilia function

Cilia are conserved microtubule-based organelles required for signaling and fluid transport, and their dysfunction causes ciliopathies. Clinical overlap between sensory and motile ciliopathies suggests that primary and motile ciliogenesis depend on shared regulatory modules. Here, we identify Centrosome and Spindle Pole-associated Protein 1 (CSPP1), a microtubule-associated protein mutated in the neurodevelopmental ciliopathy Joubert syndrome, as a conserved regulator of vertebrate multiciliogenesis. Using mouse tracheal epithelial cultures and Xenopus embryonic epidermis, we show that CSPP1 localizes to fibrous granules and deuterosomes during centriole amplification, and to basal bodies and ciliary axonemes in differentiated multiciliated cells. Loss of CSPP1 impairs centriole amplification, basal body apical migration, spacing, and rotational polarity, and is accompanied by disorganization of the apical microtubule network. CSPP1 depletion also disrupts axoneme assembly, resulting in fewer and shorter cilia with ultrastructural defects, reduced ciliary beating, and impaired cilia driven fluid flow in vivo. Together, our findings identify CSPP1 as a conserved regulator of multiciliogenesis and motile cilia function and establish a basis for future work on how shared cytoskeletal pathways may underlie overlapping features of sensory and motile ciliopathies.

cell biology↗

bioRxiv2025

Robust ciliary flows protect early Xenopus embryos from pathogens independent of multiciliated cell patterning

During the early stages of development, the skin of the Xenopus embryo is covered by around two thousand evenly distributed multiciliated cells (MCCs). This striking spatial distribution is believed to maximise the generation of superficial flows at the scale of the embryo. However, the specific role of regular MCC distribution and the physiological function of vigorous ciliary activity remain elusive. We investigate the extent to which superficial flows provide protection against external pathogens before the immune system matures, by combining experimental and computational approaches. First, we cultivated epithelial explants in order to quantify the distribution of MCCs, beating frequencies, and three-dimensional fluid flows. We then use these data to validate a computational fluid dynamics model. Using this model, seeded with structural data from whole embryos, our simulations reveal that the collective ciliary beatings create a robust liquid shield along the embryonic flank, which is highly effective at clearing pathogens from the vicinity of the epithelial surface. Through parametric analyses, we further demonstrate that this protective function is remarkably resilient. Indeed, the effectiveness of pathogen clearance is primarily governed by the overall characteristic velocity of the cilia and is less affected by moderate variations in MCC density and spatial organisation. Our findings suggest that, rather than optimising energy consumption, the biological system prioritises functional robustness to ensure reliable protection.

biophysics↗

bioRxiv2025

Deciphering the dynamic proteome of multiciliated cells

Multiciliated cells (MCCs) are essential for generating directional fluid flow across specialized epithelia in various vertebrate organs. MCC differentiation involves a unique, tightly regulated program characterized by massive centriole amplification, independently of DNA replication. Although much is known about the transcriptional control of MCC development, insights into proteome dynamics have been limited due to the lack of suitable models. In this study, we report the generation of a stable inducible MCC line, derived from Xenopus laevis A6 kidney epithelial cells. Upon induction of the MCC master regulator Multicilin (MCI), most A6-MCI cells synchronously differentiate into mature MCCs in 48 hours. Using this novel resource, custom antibodies and super-resolution imaging, we characterized Xenopus deuterosomes, the platforms that allow massive centriole synthesis in vertebrate MCCs. We performed a detailed proteomic profiling throughout MCC differentiation, and uncovered previously uncharacterized regulators. Notably, we highlight a critical role for CDK7 in MCC differentiation in both Xenopus and human systems. Our work provides a valuable resource for mechanistic studies of MCC biology and opens avenues to identify novel therapeutic targets for motile ciliopathies.

cell biology↗

bioRxiv2024

Epithelial-mesenchymal boundary guides cell shapes and axis elongation in embryonic explants

The spatial arrangement of tissues during development establishes regions of tissue-tissue interactions. While such interactions are prominent during gastrulation and organogenesis, how they guide morphogenesis remains unclear. Here, using Xenopus animal cap explants, we show that the coupling between epithelial and mesenchymal tissues is instrumental in robust axis elongation. We find that mesenchymal and epithelial tissues drive elongation hierarchically - the epithelium can elongate independently, while the mesenchyme requires the initial presence of the epithelium. The epithelial-mesenchymal boundary defines the direction of cell shape alignment and the axis of tissue elongation. Prior to explant elongation, epithelial cells align and elongate, a process that propagates into the underlying mesenchyme. These findings reveal how tissue boundaries can organize coherent axis elongation without external patterning cues, providing insights into the self-organization principles that guide embryonic morphogenesis.

developmental biology↗

bioRxiv2021

Lrrcc1 and Ccdc61 are conserved effectors of multiciliated cell function

Ciliated epithelia perform a variety of essential functions across animal evolution, ranging from locomotion of marine organisms to mucociliary clearance of airways in mammals. These epithelia are composed of multiciliated cells (MCCs) harbouring myriads of motile cilia, which rest on modified centrioles called basal bodies (BBs), and beat coordinately to generate directed fluid flows. Thus, BB biogenesis and organization is central to MCC function. In basal eukaryotes, the coiled-coil domain proteins Lrrcc1 and Ccdc61 were shown to be required for proper BB construction and function. Here, we used the Xenopus embryonic ciliated epidermis to characterize Lrrcc1 and Ccdc61 in vertebrate MCCs. We found that they both encode BB components, with a prominent association to striated rootlets. Knocking down either gene caused defects in BB docking, spacing, and polarization. Moreover, their depletion impaired the apical cytoskeleton, and altered ciliary beating. Consequently, cilia-powered fluid flow was greatly reduced in morphant tadpoles, which displayed enhanced mortality when exposed to pathogenic bacteria. This work illustrates how integration across organizational scales make elementary BB components essential for the emergence of the physiological function of ciliated epithelia.

developmental biology↗

bioRxiv2020

The SCF/KIT pathway implements self-organised epithelial patterning by cell movement

How individual cell behaviours lead to the emergence of global patterns is poorly understood. In the Xenopus embryonic epidermis, multiciliated cells (MCCs) are born in a random pattern within an inner mesenchymal layer, and subsequently intercalate at regular intervals into an outer epithelial layer. Using both experiments and mathematical modelling, we show that this transition from chaotic to ordered distribution relies on mutual repulsion among motile immature MCCs, and affinity towards outer-layer intercellular junctions. Consistently, ARP2/3-mediated actin remodelling is required for MCC pattern emergence. Using multiple functional approaches, we show that the Kit tyrosine kinase receptor, expressed in MCCs, and its ligand Scf, expressed in outer-layer cells, are both required for regular MCC distribution. While Scf behaves as a potent adhesive cue for MCCs, Kit expression is sufficient to confer order to a disordered heterologous cell population. Our work reveals how a single signalling system can implement self-organised large-scale patterning. Highlights- Immature multiciliated cells transit from a disordered to an ordered pattern - The transition is a self-organising process based on repulsive and affinity movements - ARP2/3-dependent actin remodelling is required for pattern emergence - The SCF/KIT pathway promotes both repulsion and affinity movements eTOC blurbIn developing Xenopus epidermis, immature multiciliated cells (MCCs), initially chaotically distributed within an inner layer, emerge in an orderly pattern among cells of the outer layer. This process involves MCC mutual repulsion and affinity towards outer-layer intercellular junctions. The SCF/KIT signalling pathway promotes both properties to allow regular MCC distribution.

developmental biology↗

bioRxiv2017

CDC20B is required for deuterosome-mediated centriole production in multiciliated cells

Multiciliated cells (MCCs) harbour dozens to hundreds of motile cilia, which beat in a synchronized and directional manner, thus generating hydrodynamic forces important in animal physiology. In vertebrates, MCC differentiation critically depends on the synthesis and release of numerous centrioles by specialized structures called deuterosomes. Little is known about the composition, organization and regulation of deuterosomes. Here, single-cell RNA sequencing reveals that human deuterosome-stage MCCs are characterized by the expression of many cell cycle-related genes. We further investigated the uncharacterized vertebrate-specific cell division cycle 20B (CDC20B) gene, the host gene of microRNA-449abc. We show that the CDC20B protein associates to deuterosomes and is required for the release of centrioles and the subsequent production of cilia in mouse and Xenopus MCCs. CDC20B interacts with PLK1, which has been shown to coordinate centriole disengagement with the protease Separase in mitotic cells. Strikingly, over-expression of Separase rescued centriole disengagement and cilia production in CDC20B-deficient MCCs. This work reveals the shaping of a new biological function, deuterosome-mediated centriole production in vertebrate MCCs, by adaptation of canonical and recently evolved cell cycle-related molecules.

cell biology↗