Biology subjects

Centanin, L.

Publications and source records attributed to Centanin, L..

10 recordsLinked to original sources

bioRxiv2023

Spatial transcriptomics map of the embryonic mouse brain: a tool to explore neurogenesis

The developing brain has a well-organized anatomical structure comprising different types of neural and non-neural cells. Stem cells, progenitors, and newborn neurons tightly interact with their neighbouring cells and tissue microenvironment, and this intricate interplay ultimately shapes the output of neurogenesis. Given the relevance of spatial cues during brain development, we acknowledge the necessity for a spatial transcriptomics map accessible to the neurodevelopmental community. To fulfil this need, we generated spatially-resolved RNAseq data from E13.5 mouse brain sections immunostained for mitotic active neural and vascular cells. Unsupervised clustering defined specific cell type populations of diverse lineages and differentiation states. Differential expression analysis revealed unique transcriptional signatures across specific brain areas, uncovering novel features inherent to particular anatomical domains. Finally, we integrated existing single-cell RNAseq datasets into our Spatial Transcriptomics map, adding tissue context to single-cell RNAseq data. In summary, we provide a valuable tool that enables the exploration and discovery of unforeseen molecular players involved in neurogenesis, particularly in the crosstalk between different cell types. Summary StatementDi Marco, Vazquez-Marin et al. provide an open-access spatial transcriptomics atlas of the embryonic mouse brain. This spatial map enables the exploration and discovery of gene functions within tissue context.

neuroscience↗

bioRxiv2022

Organ-Founder Stem Cells Mediate Post-Embryonic Neuromast Formation In Medaka

Mammals display a species-specific number, size and location of organs exclusively built during embryogenesis. In fish and amphibians, however, organs must adapt to life-long growth either by expanding in size and/or increasing in number. Here we use neuromasts, small sensory organs that increase in number as fish grow in size, to explore organogenesis during post-embryonic stages. Using iterative imaging, we reveal that post-embryonic organogenesis in the medaka caudal-neuromast-cluster (CNC) is mediated by organ-founder stem cells that delaminate from a functional neuromast. Organ-founder stem cells undergo epithelial-to-mesenchymal (EMT) transition as shown by molecular markers and cellular rearrangements. Chemokine signaling controls the dynamics of organ-founder stem cell delamination, which occurs at a stereotypic position that endures experimental and genetic perturbations. 2-photon laser ablation experiments reveal that organ-founder stem cells are rapidly reconstituted and suggest that these do not constitute a pre-defined population but are rather specified in situ. Our findings contribute to better understanding physiological stem-cell mediated organogenesis, a growth strategy present in life-long growing vertebrates. We speculate that a similar strategy could operate in vertebrates with determined-size as a template for pathological conditions like metastasis, where cells detach from their original organ and expand remotely.

developmental biology↗

bioRxiv2021

The human FLT1 regulatory element directs vascular expression and modulates angiogenesis pathways in vitro and in vivo

There is growing evidence that mutations in non-coding cis-regulatory elements (CREs) disrupt proper development. However, little is known about human CREs that are crucial for cardiovascular development. To address this, we bioinformatically identified cardiovascular CREs based on the occupancy of the CRE by the homeodomain protein NKX2-5 and cardiac chromatin histone modifications. This search defined a highly conserved CRE within the FLT1 locus termed enFLT1. We show that the human enFLT1 is an enhancer capable of driving reporter transgene expression in vivo throughout the developing cardiovascular system of medaka. Deletion of the human enFLT1 enhancer ({Delta}enFLT1) triggered molecular perturbations in extracellular matrix organisation and blood vessel morphogenesis in vitro in endothelial cells derived from human embryonic stem cells and vascular defects in vivo in medaka. These findings highlight the crucial role of the human FLT1 enhancer and its function as a regulator and buffer of transcriptional regulation in cardiovascular development.

genomics↗

bioRxiv2020

Identifying stem cell numbers and functional heterogeneities during post-embryonic organ growth

Uncovering the number of stem cells necessary to grow an organ has been challenging in most vertebrate systems. Here, we have developed a mathematical model that we use to characterise stem cells in the fish gill, an organ that displays non-exhaustive growth. Our work employs a Markov model, first stochastically simulated via an adapted Gillespie algorithm, and further improved by using probability theory. The stochastic algorithm produces a simulated data set for comparison with experimental data by inspecting quantifiable properties, while the analytical approach skips the step of in silico data generation and goes directly to the quantification, being more abstract and very efficient. By applying the model to a large clonal experimental dataset, we report that a reduced number of stem cells are responsible for growing and maintaining the fish gill. The model also highlights a functional heterogeneity among the stem cells involved, where activation and quiescence phases determine their relative growth contribution. Overall, our work presents an easy-to-apply algorithm to infer the number of stem cells functionally required in a life-long growing system.

systems biology↗

bioRxiv2020

Genetic Developmental Timing Revealed by Inter-Species Transplantations in Fish

The path from a fertilised egg to an embryo involves the coordinated formation of cell types, tissues and organs. Developmental modules (Raff, 1996) comprise discrete units specified by self-sufficient genetic programs that can interact among each other during embryogenesis. Here we took advantage of the different span of embryonic development between two far related teleosts, zebrafish (Danio rerio) and medaka (Oryzias latipes), of 3 and 9 days respectively, to explore modularity principles. We report that inter-species blastula transplantations result in the ectopic formation of a retina formed by donor cells -- a module. We show that the developmental time of the retina follows a genetic program: an ectopic zebrafish retina in medaka develops with zebrafish dynamics. Heterologous transplantation results in a temporal decoupling between the donor retina and host organism, illustrated by two paradigms that require retina-host interactions: lens recruitment and retino-tectal projections. Our results uncover a new experimental system to address temporal decoupling along embryonic development, and highlight the presence of largely autonomous but yet interconnected developmental modules orchestrating organogenesis.

developmental biology↗

bioRxiv2020

Tissue interactions govern pattern formation in the posterior lateral line of medaka

Vertebrate organs are arranged in a stereotypic, species-specific position along the animal body plan. Substantial morphological variation exists between related species, especially so in the vastly diversified teleost clade. It is still unclear how tissues, organs and systems can accommodate such diverse scaffolds. Here, we use the sequential formation of neuromasts in the posterior lateral line (pLL) system of medaka fish to address tissue-interactions defining a pattern. We show that the pLL pattern is established independently of its neuronal wiring, and demonstrate that the neuromast precursors that constitute the pLL behave as autonomous units during pattern construction. We uncover the necessity of epithelial integrity for correct pLL patterning by disrupting keratin 15 (krt15) and creating epithelial lesions that lead to novel neuromast positioning. By using krt15/wt chimeras, we determined that the new pLL pattern depends exclusively on the mutant epithelium, which instructs wt neuromast to locate ectopically. Inducing epithelial lesions by 2-photon laser ablation during pLL morphogenesis phenocopies krt15 genetic mutants and reveals that epithelial integrity defines the final position of the embryonic pLL neuromasts. Our results show that a fine-balance between primordium intrinsic properties and instructive interactions with the surrounding tissues is necessary to achieve proper organ morphogenesis and patterning. We speculate that this logic likely facilitates the accommodation of sensory modules to changing and diverse body plans.

developmental biology↗

bioRxiv2019

The desmosomal cadherin Desmogon is necessary for the structural integrity of the Medaka notochord

The notochord is an embryonic tissue that acts as a precursor to the spine. It is composed of outer sheath cells and inner vacuolated cells. Together they ensure the ability of the notochord to act as a hydrostatic skeleton until ossification begins. To date, there is still a paucity in our understanding of how the notochord cell types are specified and the molecular players controlling both their formation and maintenance remain poorly understood. Here we report that desmogon, a desmosomal cadherin, is essential for proper vacuolated cell shape and therefore correct notochord morphology. We trace desmogon+ precursors and uncover an early developmental heterogeneity that dictates the balance of vacuolated and sheath cell formation. We demonstrate that the growth of vacuolated cells occurs asynchronously and reveal the presence of distinct injury sensing mechanisms in the notochord. Additionally, using a small-scale F0 CRISPR screen we implicate uncharacterized genes in notochordal integrity.

developmental biology↗

bioRxiv2018

Hierarchical stem cell topography splits growth and homeostatic functions in the fish gill

While lower vertebrates contain adult stem cells (aSCs) that maintain homeostasis and drive unexhaustive organismal growth, mammalian aSCs display mainly the homeostatic function. Understanding aSC-driven growth is of paramount importance to promote organ regeneration and prevent tumor formation in mammals. Here we present a clonal approach to address common or dedicated populations of aSCs for homeostasis and growth. Our functional assays on medaka gills demonstrate the existence of separate homeostatic and growth aSCs, which are clonal but differ in their topology. While homeostatic aSCs are fixed, embedded in the tissue, growth aSCs locate at the expanding peripheral zone. Modifications in tissue architecture can convert the homeostatic zone into a growth zone, indicating a leading role for the physical niche defining stem cell output. We hypothesize that physical niches are main players to restrict aSCs to a homeostatic function in animals with a fixed adult size.

developmental biology↗

bioRxiv2018

Retinal stem cells modulate proliferative parameters to coordinate post-embryonic morphogenesis in the eye of fish

A fundamental question in biology is how anatomically and functionally distinct tissues coordinate to direct growth and shape in complex organs. We address this question using as a model the eye of teleost fish, which grow while maintaining the precise shape needed for vision throughout the animals life.\n\nCombining clonal analysis in the eye of the teleost medaka (Oryzias latipes) with a computational agent based model, we find that the neural retina (NR) and retinal pigmented epithelium (RPE) differentially modulate cell divisions to coordinate their growth rates. Cell divisions in the NR are less stochastic, consistent with an upstream role as an inducer of growth in nearby tissues. Cells in the RPE display much higher stochasticity, consistent with a downstream role responding to inductive signals.\n\nOur simulation predicts that the segregation of stem- and progenitor cell domains in the retinal ciliary marginal zone niche is an emergent property, as the topology of the niche preconditions the system to undergo a spatially biased stochastic neutral drift. Clone properties in the NR support this prediction, and further suggest that NR cells control the direction of division axes to regulate organ shape and retinal cell topology.\n\nThis work highlights an as yet unappreciated mechanism for growth coordination in a complex organ, where one tissue integrates external and internal cues as a hub to synchronize growth rates in nearby tissues. In the eye of fish, proliferation parameters of neuroretinal stem cells are a minimal target node for evolution to exploit to adapt whole-organ morphogenesis in a complex vertebrate organ.

developmental biology↗

bioRxiv2017

Neural stem cells induce the formation of their physical niche during organogenesis

Most organs rely on stem cells to maintain homeostasis during post-embryonic life. Typically, stem cells of independent lineages work coordinately within mature organs to ensure proper ratios of cell types. Little is known, however, on how these different stem cells locate to forming organs during development. Here we show that neuromasts of the posterior lateral line in medaka are composed of two independent life-long lineages with different embryonic origins. Clonal analysis and 4D imaging revealed a hierarchical organisation with instructing and responding roles: an inner, neural lineage induces the formation of an outer, border cell lineage (nBC) from the skin epithelium. Our results demonstrate that the neural lineage is necessary and sufficient to generate nBCs highlighting self-organisation principles at the level of the entire embryo. We hypothesise that transformation of surrounding tissues plays a major role during the establishment of vertebrate stem cell niches.

developmental biology↗