Biology subjects

Adameyko, I.

Publications and source records attributed to Adameyko, I..

26 records · Page 2Linked to original sources

bioRxiv2022

Developmental heterogeneity of embryonic neuroendocrine chromaffin cells and their maturation dynamics

During embryonic development, nerve-associated Schwann cell precursors (SCPs) give rise to chromaffin cells of the adrenal gland via the "bridge" transient stage, according to recent functional experiments and single cell transcriptomics data from humans and mice. However, currently existing data do not resolve the finest heterogeneity of developing chromaffin populations. Here we took advantage of deep SmartSeq2 transcriptomics sequencing to expand our collection of individual cells from developing murine sympatho-adrenal anlage and uncover the microheterogeneity of embryonic chromaffin cells and corresponding developmental paths. After improving our atlas of sympatho-adrenal development and performing experimental validations, we discovered that SCPs in the local nerve show high degree of microheterogeneity corresponding to early biases towards either Schwann or chromaffin terminal fates. Furthermore, we found that a post-"bridge" population of developing chromaffin cells gives rise to persisting immature chromaffin cells and the two terminal populations (adrenergic and noradrenergic) via diverging differentiation paths. Taken together, we provide a thorough identification of novel markers of adrenergic and noradrenergic populations in developing adrenal glands and report novel differentiation micro-paths leading to them.

developmental biology↗

bioRxiv2021

Theory of branching morphogenesis by local interactions and global guidance

Branching morphogenesis governs the formation of many organs such as lung, kidney, and the neurovascular system. Many studies have explored system-specific molecular and cellular regulatory mechanisms, as well as self-organizing rules underlying branching morphogenesis. However, in addition to local cues, branched tissue growth can also be influenced by global guidance. Here, we develop a theoretical framework for a stochastic self-organized branching process in the presence of external cues. Combining analytical theory with numerical simulations, we predict differential signatures of global vs. local regulatory mechanisms on the branching pattern, such as angle distributions, domain size, and space-filling efficiency. We find that branch alignment follows a generic scaling law determined by the strength of global guidance, while local interactions influence the tissue density but not its overall territory. Finally, using zebrafish innervation as a model system, we test these key features of the model experimentally. Our work thus provides quantitative predictions to disentangle the role of different types of cues in shaping branched structures across scales.

biophysics↗

bioRxiv2021

An immature subset of neuroblastoma cells synthesizes retinoic acid and depends on this metabolite

Neuroblastoma is a pediatric tumor of the adrenergic sympathetic lineage. Most high risk neuroblastoma go in complete clinical remission by chemotherapy, which is subsequently complemented by retinoic acid (RA) maintenance therapy. However, by unresolved mechanisms most tumors ultimately relapse as therapy-resistant disease. Neuroblastoma cell lines were recently found to include, besides lineage committed adrenergic (ADRN) tumor cells, also immature mesenchymal (MES) tumor cells. Here, we report that MES-type cells synthesize RA and require this metabolite for proliferation and motility. MES cells are even resistant to RA in vitro. MES cells appear to resemble Schwann Cell Precursors (SCP), which are motile precursors of the adrenergic lineage. MES and SCP cells express shared RA-synthesis and RA-target genes. Endogenous RA synthesis and RA resistance thus stem from normal programs of lineage precursors that are maintained in an immature tumor cell fraction. These cells are fully malignant in orthotopic patient-derived xenograft models and may mediate development of drug-resistant relapses.

cancer biology↗

bioRxiv2021

Single-nuclei transcriptomes from human adrenal gland reveals distinct cellular identities of low and high-risk neuroblastoma tumors.

Childhood neuroblastoma has a remarkable variability in outcome. Age at diagnosis is one of the most important prognostic factors, with children less than 1 year old having favorable outcomes. We studied single-cell and single-nuclei transcriptomes of neuroblastoma with different clinical risk groups and stages, including healthy adrenal gland. We compared tumor cell populations with embryonic mouse sympatho-adrenal derivatives, and post-natal human adrenal gland. We provide evidence that low and high-risk neuroblastoma have different cell identities, representing two disease entities. Low-risk neuroblastoma presents a transcriptome that resembles sympatho- and chromaffin cells, whereas malignant cells enriched in high-risk neuroblastoma resembles an unknown subtype of TRKB+ cholinergic progenitor population identified in human post-natal gland. Analyses of these populations revealed different gene expression programs for worst and better survival in correlation with age at diagnosis. Our findings reveal two cellular identities and a composition of human neuroblastoma tumors reflecting clinical heterogeneity and outcome.

cancer biology↗

bioRxiv2020

Malignant Schwann cell precursors mediate intratumoral plasticity in human neuroblastoma

Neuroblastoma is a heterogeneous embryonal malignancy and the most deadly tumor of childhood, although a minor subset may show spontaneous differentiation. It arises from the multipotent neural crest lineage during development. Some of this multipotency is retained in neuroblastoma, which can give rise to both adrenergic and mesenchymal tumor cells. The mechanisms enabling such dual fates are unknown, but likely help neuroblastoma to evade existing therapies. To understand neuroblastoma plasticity, we analyzed patient tumors using single-cell transcriptomics. In addition to the heterogeneous adrenergic and mesenchymal populations, we identify a subpopulation of malignant cells resembling Schwann cell precursors (SCPs). This SCP-like population connects the adrenergic and mesenchymal compartments through transitions structurally reminiscent of the SCP cell-fate decision fork that occurs during normal development. While the directionality of such transitions in neuroblastoma remains to be established, this finding expands the potential reservoirs of malignant cells, and suggests intratumoral plasticity mechanisms relevant for therapeutic resistance and relapse.

cancer biology↗

bioRxiv2019

Prototypical pacemaker neurons are immunocompetent cells

Pacemaker neurons exert control over neuronal circuit function by their intrinsic ability to generate rhythmic bursts of action potential. Recent work has identified rhythmic gut contractions in human, mice and hydra to be dependent on both neurons and the resident microbiota. However, little is known about the evolutionary origin of these neurons and their interaction with microbes. In this study, we identified and functionally characterized prototypical ANO/SCN/TRPM ion channel expressing pacemaker cells in the basal metazoan Hydra by using a combination of single-cell transcriptomics, immunochemistry, and functional experiments. Unexpectedly, these prototypical pacemaker neurons express a rich set of immune-related genes mediating their interaction with the microbial environment. Functional experiments validated a model of the evolutionary emergence of pacemaker cells as neurons using components of innate immunity to interact with the microbial environment and ion channels to generate rhythmic contractions.

developmental biology↗

bioRxiv2019

Secondary ossification centers evolved to make endochondral bone growth possible under the weight-bearing demands of a terrestrial environment

Growth plate and articular cartilage constitute a single anatomical entity early in development, but later separate into two distinct structures by the secondary ossification center (SOC). The reason for such separation remains unknown. We found that evolutionarily SOC appears in animals conquering the land - amniotes. Analysis of ossification pattern in mammals with specialized extremities (whales, bats, jerboa) revealed that SOC development correlates with the extent of mechanical loads. Mathematical modelling revealed that SOC reduces mechanical stress within the growth plate. Functional experiments revealed high vulnerability of hypertrophic chondrocytes to mechanical stress and showed that SOC protects these cells from apoptosis caused by extensive loading. Atomic force microscopy showed that hypertrophic chondrocytes are the least mechanically stiff cells within the growth plate. Altogether, these findings suggest that SOC has evolved to protect the hypertrophic chondrocytes from the high mechanical stress encountered in the terrestrial environment.

evolutionary biology↗

bioRxiv2017

RNA velocity in single cells

RNA abundance is a powerful indicator of the state of individual cells, but does not directly reveal dynamic processes such as cellular differentiation. Here we show that RNA velocity--the time derivative of RNA abundance--can be estimated by distinguishing unspliced and spliced mRNAs in standard single-cell RNA sequencing protocols. We show that RNA velocity is a vector that predicts the future state of individual cells on a timescale of hours. We validate the accuracy of RNA velocity in the neural crest lineage, demonstrate its use on multiple technical platforms, reconstruct the branching lineage tree of the mouse hippocampus, and measure RNA kinetics in human embryonic brain. We expect RNA velocity to greatly aid the analysis of developmental lineages and cellular dynamics, particularly in humans.

genomics↗