High-resolution single cell transcriptome analysis of zebrafish sensory hair cell regeneration

Loss of sensory hair cells in the mammalian inner ear leads to permanent hearing and vestibular defects, whereas loss of hair cells in zebrafish results in their regeneration. We used scRNA-Seq to characterize the transcriptional dynamics of hair cell regeneration in zebrafish at unprecedented spatio-temporal resolution. We uncovered three, sequentially activated modules. First, an injury/inflammatory response and downregulation of progenitor/stem cell maintenance genes within minutes after hair cell loss. Second, the transient activation of regeneration-specific genes. And third, a robust reactivation of developmental gene programs, including hair cell specification, cell cycle activation, ribosome biogenesis, and a metabolic switch to oxidative phosphorylation. The results are not only relevant for our understanding of hair cell regeneration and how we might be able to trigger it in mammals but also for regenerative processes in general. The data is searchable and publicly accessible via a web-based interface.

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Comparing Sensory Organs to Define the Path for Hair Cell Regeneration

Annual Review of Cell and Developmental Biology ◽

10.1146/annurev-cellbio-100818-125503 ◽

2019 ◽

Vol 35 (1) ◽

pp. 567-589 ◽

Cited By ~ 5

Author(s):

Nicolas Denans ◽

Sungmin Baek ◽

Tatjana Piotrowski

Keyword(s):

Hair Cell ◽

Olfactory Epithelium ◽

Current Literature ◽

Hair Cells ◽

Sensory Cell ◽

Cell Regeneration ◽

Hair Cell Regeneration ◽

Sensory Hair ◽

Sensory Hair Cells ◽

Technical Advances

Deafness or hearing deficits are debilitating conditions. They are often caused by loss of sensory hair cells or defects in their function. In contrast to mammals, nonmammalian vertebrates robustly regenerate hair cells after injury. Studying the molecular and cellular basis of nonmammalian vertebrate hair cell regeneration provides valuable insights into developing cures for human deafness. In this review, we discuss the current literature on hair cell regeneration in the context of other models for sensory cell regeneration, such as the retina and the olfactory epithelium. This comparison reveals commonalities with, as well as differences between, the different regenerating systems, which begin to define a cellular and molecular blueprint of regeneration. In addition, we propose how new technical advances can address outstanding questions in the field.

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Hair cell regeneration and recovery of the vestibuloocular reflex in the avian vestibular system

Journal of Neurophysiology ◽

10.1152/jn.1996.76.5.3301 ◽

1996 ◽

Vol 76 (5) ◽

pp. 3301-3312 ◽

Cited By ~ 35

Author(s):

J. P. Carey ◽

A. F. Fuchs ◽

E. W. Rubel

Keyword(s):

Hair Cell ◽

Cell Density ◽

Hair Cells ◽

Cell Damage ◽

Cell Loss ◽

Average Density ◽

Cell Regeneration ◽

Vestibuloocular Reflex ◽

Scanning Electron Micrographs ◽

Hair Cell Regeneration

1. Although auditory and vestibular hair cells are known to regenerate after aminoglycoside intoxication in birds, there is only sparse evidence that the regenerated hair cells are functional. To address this issue, we examined the relation of hair cell regeneration to recovery of the vestibuloocular reflex (VOR), whose afferent signal originates at hair cells in the vestibular epithelium. Hair cell damage was produced by treating white Leghorn chicks (Gallus domesticus, 4–8 days posthatch) with streptomycin sulfate in normal saline (1,200 mg.kg-1.day-1 im) for 5 days. 2. In the 1st wk after treatment, the VOR gain was essentially 0, and hair cell density as assessed by light microscopy was approximately 40% of normal. Between the 1st and 3rd wk after treatment, the VOR was present. Although VOR gain varied considerably from one chick to another, it increased, on average, between the 1st and 3rd wk, as did the average hair cell density. At the end of 8–9 wk, the gain and phase of the VOR had returned to normal values, as had the average density of hair cells. 3. Therefore, despite the catastrophic initial effect of hair cell loss on the VOR, recovered hair cells appeared to restore the VOR completely. Average hair cell density increased with average VOR gain. VOR gain correlated better with recovery of type 1 hair cells than with recovery of type II hair cells. 4. In contrast to hair cell density, the appearance of the vestibular epithelia as assessed by hair cell stereocilia in scanning electron micrographs was a poor indicator of VOR gain. In both treated and control birds, epithelia with the same appearance could have quite different VOR gains, suggesting a variation in the functional viability of the hair cells. 5. This observation suggests that several factors, such as the repair of stereocilia, the efficacy of hair cell synapses on afferent fibers, and the extent of compensation by central vestibular pathways, may affect the recovery of VOR gain. However, our data suggest that hair cell regeneration plays an important role in this recovery.

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Hair cell regeneration after acoustic trauma in adult Coturnix quail

Science ◽

10.1126/science.3381101 ◽

1988 ◽

Vol 240 (4860) ◽

pp. 1774-1776 ◽

Cited By ~ 477

Author(s):

BM Ryals ◽

EW Rubel

Keyword(s):

Hair Cell ◽

Hair Cells ◽

Cell Loss ◽

Acoustic Trauma ◽

Cell Regeneration ◽

Hair Cell Loss ◽

Hair Cell Regeneration ◽

Supporting Cells ◽

Coturnix Quail ◽

Original Number

Recovery of hair cells was studied at various times after acoustic trauma in adult quail. An initial loss of hair cells recovered to within 5 percent of the original number of cells. Tritium-labeled thymidine was injected after this acoustic trauma to determine if mitosis played a role in recovery of hair cells. Within 10 days of acoustic trauma, incorporation of [3H]thymidine was seen over the nuclei of hair cells and supporting cells in the region of initial hair cell loss. Thus, hair cell regeneration can occur after embryonic terminal mitosis.

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A model for reticular dysgenesis shows impaired sensory organ development and hair cell regeneration linked to cellular stress

10.1101/610204 ◽

2019 ◽

Author(s):

Alberto Rissone ◽

Erin Jimenez ◽

Kevin Bishop ◽

Blake Carrington ◽

Claire Slevin ◽

...

Keyword(s):

Hair Cell ◽

Hair Cells ◽

Therapeutic Option ◽

Sensory Organ ◽

Therapeutic Modality ◽

Cell Regeneration ◽

Organ Development ◽

Hair Cell Regeneration ◽

Sensory Hair ◽

Sensory Hair Cells

AbstractMutations in the gene AK2 are responsible for Reticular Dysgenesis (RD), a rare and severe form of primary immunodeficiency in children. RD patients have a severely shortened life expectancy and without treatment die a few weeks after birth. The only available therapeutic option for RD is bone marrow transplantation. To gain insight into the pathophysiology of RD, we previously created zebrafish models for an AK2 deficiency. One of the clinical features of RD is hearing loss, but its pathology and causes have not been determined. In adult mammals, sensory hair cells of the inner ear do not regenerate; however, their regeneration has been observed in several non-mammalian vertebrates, including zebrafish. Therefore, we use our RD zebrafish models to determine if AK2 deficiency affects sensory organ development and/or hair cell regeneration. Our studies indicated that AK2 is required for the correct development, survival and regeneration of sensory hair cells. Interestingly, AK2 deficiency induces the expression of several oxidative stress markers and it triggers an increased level of cell death in the hair cells. Finally, we show that glutathione treatment can partially rescue hair cell development in the sensory organs in our RD models, pointing to the potential use of antioxidants as a supportive therapeutic modality for RD patients, not only to increase their chances of survival, but to prevent or ameliorate their sensorineural hearing deficits.

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Single cell RNA-Seq reveals distinct stem cell populations that drive sensory hair cell regeneration in response to loss of Fgf and Notch signaling

10.1101/496612 ◽

2018 ◽

Author(s):

Mark E. Lush ◽

Daniel C. Diaz ◽

Nina Koenecke ◽

Sungmin Baek ◽

Helena Boldt ◽

...

Keyword(s):

Hair Cell ◽

Notch Signaling ◽

Single Cell ◽

Lateral Line ◽

Hair Cells ◽

Developmental Trajectory ◽

Cell Regeneration ◽

Hair Cell Regeneration ◽

Specific Expression ◽

Sensory Hair

AbstractLoss of sensory hair cells leads to deafness and balance deficiencies. In contrast to mammalian hair cells, zebrafish ear and lateral line hair cells regenerate from poorly characterized, proliferating support cells. Equally ill-defined is the gene regulatory network underlying the progression of support cells to cycling hair cell progenitors and differentiated hair cells. We used single cell RNA-Sequencing (scRNA-Seq) of lateral line sensory organs and uncovered five different support cell types, including quiescent and activated stem cells. In silico ordering of support cells along a developmental trajectory identified cells that self-renew and new groups of genes required for hair cell differentiation. scRNA-Seq analyses of fgf3 mutants, in which hair cell regeneration is increased, demonstrates that Fgf and Notch signaling inhibit proliferation of support cells in parallel by inhibiting Wnt signaling. Our scRNA-Seq analyses set the foundation for mechanistic studies of sensory organ regeneration and is crucial for identifying factors to trigger hair cell production in mammals. As a resource, we implemented a shiny application that allows the community to interrogate cell type specific expression of genes of interest.

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Protection of Cochlear Hair Cells from Gentamicin Ototoxicity and Mechanisms of Mammalian Hair Cell Regeneration in Vitro

Cell and Molecular Biology of the Ear ◽

10.1007/978-1-4615-4223-0_14 ◽

2000 ◽

pp. 183-197

Author(s):

Wei-Qiang Gao

Keyword(s):

Hair Cell ◽

Hair Cells ◽

Cell Regeneration ◽

Hair Cell Regeneration ◽

Cochlear Hair Cells ◽

Regeneration In Vitro ◽

Gentamicin Ototoxicity ◽

Mammalian Hair

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Delta1 expression during avian hair cell regeneration

Development ◽

10.1242/dev.126.5.961 ◽

1999 ◽

Vol 126 (5) ◽

pp. 961-973 ◽

Cited By ~ 3

Author(s):

J.S. Stone ◽

E.W. Rubel

Keyword(s):

Hair Cell ◽

Inner Ear ◽

Hair Cells ◽

Cell Injury ◽

Basilar Papilla ◽

Cell Regeneration ◽

Mrna Levels ◽

Hair Cell Regeneration ◽

Drug Induced ◽

In Cells

Postembryonic production of hair cells, the highly specialized receptors for hearing, balance and motion detection, occurs in a precisely controlled manner in select species, including avians. Notch1, Delta1 and Serrate1 mediate cell specification in several tissues and species. We examined expression of the chicken homologs of these genes in the normal and drug-damaged chick inner ear to determine if signaling through this pathway changes during hair cell regeneration. In untreated post-hatch chicks, Delta1 mRNA is abundant in a subpopulation of cells in the utricle, which undergoes continual postembryonic hair cell production, but it is absent from all cells in the basilar papilla, which is mitotically quiescent. By 3 days after drug-induced hair cell injury, Delta1 expression is highly upregulated in areas of cell proliferation in both the utricle and basilar papilla. Delta1 mRNA levels are elevated in progenitor cells during DNA synthesis and/or gap 2 phases of the cell cycle and expression is maintained in both daughter cells immediately after mitosis. Delta1 expression remains upregulated in cells that differentiate into hair cells and is downregulated in cells that do not acquire the hair cell fate. Delta1 mRNA levels return to normal by 10 days after hair cell injury. Serrate1 is expressed in both hair cells and support cells in the utricle and basilar papilla, and its expression does not change during the course of drug-induced hair cell regeneration. In contrast, Notch1 expression, which is limited to support cells in the quiescent epithelium, is increased in post-M-phase cell pairs during hair cell regeneration. This study provides initial evidence that Delta-Notch signaling may be involved in maintaining the correct cell types and patterns during postembryonic replacement of sensory epithelial cells in the chick inner ear.

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