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Dabdoub, A.

Publications and source records attributed to Dabdoub, A..

5 recordsLinked to original sources

A comparative single-cell transcriptomic atlas for diverse populations of vertebrate hair cells

Mechanosensitive hair cells vary widely in morphology and regenerative capacity across vertebrate organs and species. To investigate their underlying transcriptomic diversity, we integrated human, mouse, chicken, and zebrafish single-cell and single-nucleus RNA sequencing datasets and assembled a cross-species atlas of hair cells spanning organs, developmental stages, and species. Analysis of 29 hair cell populations, encompassing the major cochlear, vestibular, and lateral-line hair cell types, identified approximately 5,000 genes enriched in at least one hair cell population compared to supporting cells from the same organs. Unsupervised clustering of these hair cell-enriched (HCE) genes defined species-, organ-, and hair cell state-associated cohorts as well as broadly conserved hair cell-enriched programs. Using an AUC-based scoring framework, we further defined 884 pan hair cell-enriched (pan-HCE) genes with elevated expression in most developing and/or mature hair cell populations, including genes implicated in deafness, mechanotransduction, and synaptic transmission, along with genes not previously linked to hair cell function. Independent analysis of developing hair cells using the same metrics stratified pan-HCE genes based on when they are first enriched and identified an additional 97 genes that are transiently enriched. We used the pan- and developing HCE gene sets to assess transcriptional similarity between baseline hair cell states and hair cells produced during avian hair cell regeneration and in mouse cochlear organoids, as well as hair cell-like populations produced by fibroblast reprogramming. HCE gene sets with different developmental dynamics identified young vs. more mature hair cells when projected onto independent single-cell RNA sequencing datasets from developing zebrafish, mouse, and human. We provide a web-based resource of all HCE metrics and expression profiles, enabling future exploration of vertebrate hair cell gene expression across organs, species, and experimental contexts.

neuroscience↗

Spatiotemporal cellular landscape of the human utricle sensory epithelium

Vestibular dysfunction affects individuals of all ages and becomes increasingly common with age. Despite the essential role of the utricle in balance, its molecular states and tissue architecture in humans remain poorly defined. Here, we integrated paired single-nucleus transcriptomic and epigenomic profiling with imaging-based spatial transcriptomics to characterize the human fetal utricle and its spatiotemporal patterning. We resolved transcriptionally heterogeneous, spatially segregated populations of sensory and nonsensory epithelial cells and reconstructed sensory cell differentiation across three gestational ages, showing that these cells acquire region-specific transcriptional signatures before final subtype specification. We further uncover a progressive decline in nonsensory cell proliferation accompanied by chromatin remodelling, as well as transitional epithelial populations with distinct spatial and regulatory programs. Together, these data define the molecular and spatial dynamics of the human fetal utricle and reveal cell states and regulatory pathways that provide a foundation for studying vestibular disorders and regeneration. HIGHLIGHTSO_LISpatial identity of utricular sensory hair cells precedes full subtype specification C_LIO_LIDistinct transcriptional regulators control hair cell fate and regional patterning C_LIO_LISupporting cells remodel chromatin as their proliferative capacity declines C_LIO_LITransitional epithelial cells adopt ordered states along the utricular border C_LIO_LISensory and nonsensory cells show divergent regulatory and signalling programs C_LI

cell biology↗

Trophic and temporal dynamics of macrophage biology in human inner ear organogenesis

Recent single-cell transcriptomic approaches are uncovering the breadth and depth of cell diversity within the mammalian inner ear. Macrophages, detected from gestational week 7 in the human inner ear, persist into adulthood, and yet remain poorly understood in terms of their origin and function. Using self-generated and public scRNA-seq data, we identify seven distinct macrophage subtypes spanning fetal weeks 7.5 to 16.4 and adulthood. Each macrophage subtype is linked to specific developmental stages and displays a unique gene expression profile. These findings corroborate earlier histological evidence of resident and non-resident macrophages in both the developing and adult human cochlea. We also show that the human inner ear is seeded by macrophages from both embryonic and more definitive sources, corroborating studies in mouse. By analyzing ligand-receptor interactions, we highlight potential macrophage contributions to inner ear organogenesis. This research provides new insights into the diverse roles of human inner ear macrophages.

bioinformatics↗

Molecular differences between neonatal and adult stria vascularis from organotypic explants and transcriptomics

SummaryThe stria vascularis (SV), part of the blood-labyrinth barrier, is an essential component of the inner ear that regulates the ionic environment required for hearing. SV degeneration disrupts cochlear homeostasis, leading to irreversible hearing loss, yet a comprehensive understanding of the SV, and consequently therapeutic availability for SV degeneration, is lacking. We developed a whole-tissue explant model from neonatal and adult mice to create a robust platform for SV research. We validated our model by demonstrating that the proliferative behaviour of the SV in vitro mimics SV in vivo, providing a representative model and advancing high-throughput SV research. We also provided evidence for pharmacological intervention in our system by investigating the role of Wnt/{beta}-catenin signaling in SV proliferation. Finally, we performed single-cell RNA sequencing from in vivo neonatal and adult mouse SV and revealed key genes and pathways that may play a role in SV proliferation and maintenance. Together, our results contribute new insights into investigating biological solutions for SV-associated hearing loss. SignificanceHearing loss impairs our ability to communicate with people and interact with our environment. This can lead to social isolation, depression, cognitive deficits, and dementia. Inner ear degeneration is a primary cause of hearing loss, and our study provides an in depth look at one of the major sites of inner ear degeneration: the stria vascularis. The stria vascularis and associated blood-labyrinth barrier maintain the functional integrity of the auditory system, yet it is relatively understudied. By developing a new in vitro model for the young and adult stria vascularis and using single cell RNA sequencing, our study provides a novel approach to studying this tissue, contributing new insights and widespread implications for auditory neuroscience and regenerative medicine. Highlights- We established an organotypic explant system of the neonatal and adult stria vascularis with an intact blood-labyrinth barrier. - Proliferation of the stria vascularis decreases with age in vitro, modelling its proliferative behaviour in vivo. - Pharmacological studies using our in vitro SV model open possibilities for testing injury paradigms and therapeutic interventions. - Inhibition of Wnt signalling decreases proliferation in neonatal stria vascularis. - We identified key genes and transcription factors unique to developing and mature SV cell types using single cell RNA sequencing.

molecular biology↗

Pericytes control vascular stability and auditory spiral ganglion neuron survival

The inner ear has a rich population of pericytes, a multi-functional mural cell essential for sensory hair cell heath and normal hearing. However, the mechanics of how pericytes contribute to the homeostasis of the auditory vascular-neuronal complex in the spiral ganglion is not yet known. In this study, using an inducible and conditional pericyte depletion mouse (PdgfrbCreERT2+/-; ROSA26iDTR+/-) model, we demonstrate, for the first time, that pericyte depletion causes loss of vascular volume and spiral ganglion neurons (SGNs) and adversely affects hearing sensitivity. Using an in vitro trans-well co-culture system, we show pericytes markedly promote neurite and vascular branch growth in neonatal SGN explants and adult SGNs. The pericyte-controlled neural growth is strongly mediated by pericyte-released exosomes containing vascular endothelial growth factor-A (VEGF-A). Treatment of neonatal SGN explants or adult SGNs with pericyte-derived exosomes significantly enhances angiogenesis, SGN survival, and neurite growth, all of which were inhibited by a selective blocker of the VEGF receptor 2 (Flk1). Our study demonstrates that pericytes in the adult ear are critical for vascular stability and SGN health. Cross-talk between pericytes and SGNs via exosomes is essential for neuronal and vascular health and normal hearing.

neuroscience↗