The Kinocilia of Cochlear Hair Cells: Structures, Functions, and Diseases

Wang, Difei; Zhou, Jun

doi:10.3389/fcell.2021.715037

Cited by 23 publications

(20 citation statements)

References 49 publications

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“…In prenatal mice, ACF7 is required for normal kinocilia lengths ( May-Simera and Kelley, 2012 ). Therefore, we tested if kinocilia lengths were altered in P5 Macf1 fl/– ; Pax2-Cre mice, a timepoint during cochlear development that was chosen because it is before the kinocilia degenerate ( Wang and Zhou, 2021 ) but should still also reflect defects in kinocilia formation if they do exist in these conditional knockout animals. Using anti-acetylated tubulin to label the kinocilia and confocal microscope software for measurements, we showed that the mean length of kinocilia from control mice is 2.49 ± 0.02 μm (mean ± SEM) ( Figure 4 ).…”

Section: Resultsmentioning

confidence: 99%

Actin Crosslinking Family Protein 7 Deficiency Does Not Impair Hearing in Young Mice

Gilbert

Zhu

Salameh

et al. 2021

Front. Cell Dev. Biol.

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To enable hearing, the sensory hair cell contains specialized subcellular structures at its apical region, including the actin-rich cuticular plate and circumferential band. ACF7 (actin crosslinking family protein 7), encoded by the gene Macf1 (microtubule and actin crosslinking factor 1), is a large cytoskeletal crosslinking protein that interacts with microtubules and filamentous actin to shape cells. ACF7 localizes to the cuticular plate and the circumferential band in the hair cells of vertebrates. The compelling expression pattern of ACF7 in hair cells, combined with conserved roles of this protein in the cytoskeleton of various cell types in invertebrates and vertebrates, led to the hypothesis that ACF7 performs a key function in the subcellular architecture of hair cells. To test the hypothesis, we conditionally target Macf1 in the inner ears of mice. Surprisingly, our data show that in young, but mature, conditional knockout mice cochlear hair cell survival, planar cell polarity, organization of the hair cells within the organ of Corti, and capacity to hear are not significantly impacted. Overall, these results fail to support the hypothesis that ACF7 is an essential hair cell protein in young mice, and the purpose of ACF7 expression in the hair cell remains to be understood.

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Section: Resultsmentioning

confidence: 99%

Actin Crosslinking Family Protein 7 Deficiency Does Not Impair Hearing in Young Mice

Gilbert

Zhu

Salameh

et al. 2021

Front. Cell Dev. Biol.

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“…Even if kinocilium may present a motile structure (9 + 2), it is considered a nonmotile cilium, lacking inner dynein arms [ 42 ]. Degeneration of kinocilium under maturation of the ear leads to inner and outer hair cells without kinocilia.…”

Section: Genetics Of Ushmentioning

confidence: 99%

Usher Syndrome

Castiglione

Möller

2022

Audiology Research

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Usher syndrome (USH) is the most common genetic condition responsible for combined loss of hearing and vision. Balance disorders and bilateral vestibular areflexia are also observed in some cases. The syndrome was first described by Albrecht von Graefe in 1858, but later named by Charles Usher, who presented a large number of cases with hearing loss and retinopathy in 1914. USH has been grouped into three main clinical types: 1, 2, and 3, which are caused by mutations in different genes and are further divided into different subtypes. To date, nine causative genes have been identified and confirmed as responsible for the syndrome when mutated: MYO7A, USH1C, CDH23, PCDH15, and USH1G (SANS) for Usher type 1; USH2A, ADGRV1, and WHRN for Usher type 2; CLRN1 for Usher type 3. USH is inherited in an autosomal recessive pattern. Digenic, bi-allelic, and polygenic forms have also been reported, in addition to dominant or nonsyndromic forms of genetic mutations. This narrative review reports the causative forms, diagnosis, prognosis, epidemiology, rehabilitation, research, and new treatments of USH.

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“…These tip links are coupled to the mechanosensitive ion channels at the tips of the shorter stereocilia. The longest stereocilia are attached to a microtubule-based protrusion known as kinocilium [302]. Mechanical tension generated in the tip links by deflection of the bundle of stereocilia results in the opening of the ion channels thereby triggering mechano-electrical transduction.…”

Section: Stereociliamentioning

confidence: 99%

Length control of long cell protrusions: rulers, timers and transport

Patra¹,

Chowdhury²,

Jülicher³

2022

Preprint

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A living cell uses long tubular appendages for locomotion and sensory purposes. Hence, assembling and maintaining a protrusion of correct length is crucial for its survival and overall performance. Usually the protrusions lack the machinery for the synthesis of building blocks and imports them from the cell body. What are the unique features of the transport logistics which facilitate the exchange of these building blocks between the cell and the protrusion? What kind of 'rulers' and 'timers' does the cell use for constructing its appendages of correct length on time? How do the multiple appendages coordinate and communicate among themselves during different stages of their existence? How frequently do the fluctuations drive the length of these dynamic protrusions out of the acceptable bounds? These questions are addressed from a broad perspective in this review which is organized in three parts. In part-I the list of all known cell protrusions is followed by a comprehensive list of the mechanisms of length control of cell protrusions reported in the literature. We review not only the dynamics of the genesis of the protrusions, but also their resorption and regrowth as well as regeneration after amputation. As a case study in part-II, the specific cell protrusion that has been discussed in detail is eukaryotic flagellum (also known as cilium); this choice was dictated by the fact that flagellar length control mechanisms have been studied most extensively over more than half a century in cells with two or more flagella. Although limited in scope, brief discussions on a few non-flagellar cell protrusions in part-III of this review is intended to provide a glimpse of the uncharted territories and challenging frontiers of research on subcellular length control phenomena that awaits vigorous investigations.

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The Kinocilia of Cochlear Hair Cells: Structures, Functions, and Diseases

Cited by 23 publications

References 49 publications

Actin Crosslinking Family Protein 7 Deficiency Does Not Impair Hearing in Young Mice

Actin Crosslinking Family Protein 7 Deficiency Does Not Impair Hearing in Young Mice

Usher Syndrome

Length control of long cell protrusions: rulers, timers and transport

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