Congenital sensorineural hearing loss as the initial presentation of PTPN11-associated Noonan syndrome with multiple lentigines or Noonan syndrome: clinical features and underlying mechanisms

2020 ◽  
pp. jmedgenet-2020-106892
Author(s):  
Xue Gao ◽  
Sha-Sha Huang ◽  
Shi-Wei Qiu ◽  
Yu Su ◽  
Wei-Qian Wang ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Hair Cells ◽  
Noonan Syndrome ◽  
Sensorineural Hearing ◽  
Supporting Cells ◽  
Pathogenic Variants ◽  
Underlying Mechanisms ◽  
Ganglion Neurons ◽  
Multiple Lentigines

BackgroundGermline variants in PTPN11 are the primary cause of Noonan syndrome with multiple lentigines (NSML) and Noonan syndrome (NS), which share common skin and facial symptoms, cardiac anomalies and retardation of growth. Hearing loss is considered an infrequent feature in patients with NSML/NS. However, in our cohort, we identified a group of patients with PTPN11 pathogenic variants that were primarily manifested in congenital sensorineural hearing loss (SNHL). This study evaluated the incidence of PTPN11-related NSML or NS in patients with congenital SNHL and explored the expression of PTPN11 and the underlying mechanisms in the auditory system.MethodsA total of 1502 patients with congenital SNHL were enrolled. Detailed phenotype-genotype correlations were analysed in patients with PTPN11 variants. Immunolabelling of Ptpn11 was performed in P35 mice. Zebrafish with Ptpn11 knockdown/mutant overexpression were constructed to further explore mechanism underlying the phenotypes.ResultsTen NSML/NS probands were diagnosed via the identification of pathogenic variants of PTPN11, which accounted for ~0.67% of the congenital SNHL cases. In mice cochlea, Shp2, which is encoded by Ptpn11, is distributed in the spiral ganglion neurons, hair cells and supporting cells of the inner ear. In zebrafish, knockdown of ptpn11a and overexpression of mutant PTPN11 were associated with a significant decrease in hair cells and supporting cells. We concluded that congenital SNHL could be a major symptom in PTPN11-associated NSML or NS. Other features may be mild, especially in children.ConclusionScreening for PTPN11 in patients with congenital hearing loss and variant-based diagnoses are recommended.

scholarly journals Autophagy Regulates the Survival of Hair Cells and Spiral Ganglion Neurons in Cases of Noise, Ototoxic Drug, and Age-Induced Sensorineural Hearing Loss

2021 ◽  
Vol 15 ◽  
Author(s):  
Lingna Guo ◽  
Wei Cao ◽  
Yuguang Niu ◽  
Shuangba He ◽  
Renjie Chai ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Hair Cells ◽  
Noise Exposure ◽  
Spiral Ganglion ◽  
Sensorineural Hearing ◽  
Spiral Ganglion Neurons ◽  
Core Components ◽  
Spontaneous Regeneration ◽  
Ganglion Neurons

Inner ear hair cells (HCs) and spiral ganglion neurons (SGNs) are the core components of the auditory system. However, they are vulnerable to genetic defects, noise exposure, ototoxic drugs and aging, and loss or damage of HCs and SGNs results in permanent hearing loss due to their limited capacity for spontaneous regeneration in mammals. Many efforts have been made to combat hearing loss including cochlear implants, HC regeneration, gene therapy, and antioxidant drugs. Here we review the role of autophagy in sensorineural hearing loss and the potential targets related to autophagy for the treatment of hearing loss.

scholarly journals Research Progress on Flat Epithelium of the Inner Ear

2020 ◽  
pp. 775-785
Author(s):  
L HE ◽  
J-Y GUO ◽  
K LIU ◽  
G-P WANG ◽  
S-S GONG
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Inner Ear ◽  
Hair Cells ◽  
Noise Exposure ◽  
Sensory Epithelium ◽  
Sensorineural Hearing ◽  
Research Progress ◽  
Supporting Cells ◽  
Mesenchymal Transition

Sensorineural hearing loss and vertigo, resulting from lesions in the sensory epithelium of the inner ear, have a high incidence worldwide. The sensory epithelium of the inner ear may exhibit extreme degeneration and is transformed to flat epithelium (FE) in humans and mice with profound sensorineural hearing loss and/or vertigo. Various factors, including ototoxic drugs, noise exposure, aging, and genetic defects, can induce FE. Both hair cells and supporting cells are severely damaged in FE, and the normal cytoarchitecture of the sensory epithelium is replaced by a monolayer of very thin, flat cells of irregular contour. The pathophysiologic mechanism of FE is unclear but involves robust cell division. The cellular origin of flat cells in FE is heterogeneous; they may be transformed from supporting cells that have lost some features of supporting cells (dedifferentiation) or may have migrated from the flanking region. The epithelial-mesenchymal transition may play an important role in this process. The treatment of FE is challenging given the severe degeneration and loss of both hair cells and supporting cells. Cochlear implant or vestibular prosthesis implantation, gene therapy, and stem cell therapy show promise for the treatment of FE, although many challenges remain to be overcome.

scholarly journals Deletion of Clusterin Protects Cochlear Hair Cells against Hair Cell Aging and Ototoxicity

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiaochang Zhao ◽  
Heidi J. Henderson ◽  
Tianying Wang ◽  
Bo Liu ◽  
Yi Li
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Sensorineural Hearing Loss ◽  
Hair Cells ◽  
Sensorineural Hearing ◽  
Cell Aging ◽  
Supporting Cells ◽  
Drug Induced ◽  
Cochlear Hair Cells ◽  
Age Related

Hearing loss is a debilitating disease that affects 10% of adults worldwide. Most sensorineural hearing loss is caused by the loss of mechanosensitive hair cells in the cochlea, often due to aging, noise, and ototoxic drugs. The identification of genes that can be targeted to slow aging and reduce the vulnerability of hair cells to insults is critical for the prevention of sensorineural hearing loss. Our previous cell-specific transcriptome analysis of adult cochlear hair cells and supporting cells showed that Clu, encoding a secreted chaperone that is involved in several basic biological events, such as cell death, tumor progression, and neurodegenerative disorders, is expressed in hair cells and supporting cells. We generated Clu-null mice (C57BL/6) to investigate its role in the organ of Corti, the sensory epithelium responsible for hearing in the mammalian cochlea. We showed that the deletion of Clu did not affect the development of hair cells and supporting cells; hair cells and supporting cells appeared normal at 1 month of age. Auditory function tests showed that Clu-null mice had hearing thresholds comparable to those of wild-type littermates before 3 months of age. Interestingly, Clu-null mice displayed less hair cell and hearing loss compared to their wildtype littermates after 3 months. Furthermore, the deletion of Clu is protected against aminoglycoside-induced hair cell loss in both in vivo and in vitro models. Our findings suggested that the inhibition of Clu expression could represent a potential therapeutic strategy for the alleviation of age-related and ototoxic drug-induced hearing loss.

scholarly journals Stem Cell-Based Therapeutic Approaches to Restore Sensorineural Hearing Loss in Mammals

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Muhammad Waqas ◽  
Iram Us-Salam ◽  
Zainab Bibi ◽  
Yunfeng Wang ◽  
He Li ◽  
...  
Keyword(s):  
Stem Cells ◽  
Hearing Loss ◽  
Stem Cell ◽  
Sensorineural Hearing Loss ◽  
Hearing Aids ◽  
Hair Cells ◽  
Sensory Epithelium ◽  
Sensorineural Hearing ◽  
Sensory Structures ◽  
Ganglion Neurons

The hair cells that reside in the cochlear sensory epithelium are the fundamental sensory structures responsible for understanding the mechanical sound waves evoked in the environment. The intense damage to these sensory structures may result in permanent hearing loss. The present strategies to rehabilitate the hearing function include either hearing aids or cochlear implants that may recover the hearing capability of deaf patients to a limited extent. Therefore, much attention has been paid on developing regenerative therapies to regenerate/replace the lost hair cells to treat the damaged cochlear sensory epithelium. The stem cell therapy is a promising approach to develop the functional hair cells and neuronal cells from endogenous and exogenous stem cell pool to recover hearing loss. In this review, we specifically discuss the potential of different kinds of stem cells that hold the potential to restore sensorineural hearing loss in mammals and comprehensively explain the current therapeutic applications of stem cells in both the human and mouse inner ear to regenerate/replace the lost hair cells and spiral ganglion neurons.

scholarly journals Noise-induced and age-related hearing loss:  new perspectives and potential therapies

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 927 ◽  
Author(s):  
M Charles Liberman
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Sensorineural Hearing Loss ◽  
Hair Cells ◽  
Auditory Nerve ◽  
Cell Loss ◽  
Sensorineural Hearing ◽  
Hair Cell Loss ◽  
Age Related ◽  
Age Related Hearing Loss

The classic view of sensorineural hearing loss has been that the primary damage targets are hair cells and that auditory nerve loss is typically secondary to hair cell degeneration. Recent work has challenged that view. In noise-induced hearing loss, exposures causing only reversible threshold shifts (and no hair cell loss) nevertheless cause permanent loss of >50% of the synaptic connections between hair cells and the auditory nerve. Similarly, in age-related hearing loss, degeneration of cochlear synapses precedes both hair cell loss and threshold elevation. This primary neural degeneration has remained a “hidden hearing loss” for two reasons: 1) the neuronal cell bodies survive for years despite loss of synaptic connection with hair cells, and 2) the degeneration is selective for auditory nerve fibers with high thresholds. Although not required for threshold detection when quiet, these high-threshold fibers are critical for hearing in noisy environments. Research suggests that primary neural degeneration is an important contributor to the perceptual handicap in sensorineural hearing loss, and it may be key to the generation of tinnitus and other associated perceptual anomalies. In cases where the hair cells survive, neurotrophin therapies can elicit neurite outgrowth from surviving auditory neurons and re-establishment of their peripheral synapses; thus, treatments may be on the horizon.

scholarly journals Using the Zebrafish Lateral Line to Understand the Roles of Mitochondria in Sensorineural Hearing Loss

2021 ◽  
Vol 8 ◽  
Author(s):  
Melanie Holmgren ◽  
Lavinia Sheets
Keyword(s):  
Cell Death ◽  
Hearing Loss ◽  
Hair Cell ◽  
Sensorineural Hearing Loss ◽  
Lateral Line ◽  
Hair Cells ◽  
High Energy ◽  
Sensorineural Hearing ◽  
Mitochondrial Activity ◽  
Ototoxic Drugs

Hair cells are the mechanosensory receptors of the inner ear and can be damaged by noise, aging, and ototoxic drugs. This damage often results in permanent sensorineural hearing loss. Hair cells have high energy demands and rely on mitochondria to produce ATP as well as contribute to intracellular calcium homeostasis. In addition to generating ATP, mitochondria produce reactive oxygen species, which can lead to oxidative stress, and regulate cell death pathways. Zebrafish lateral-line hair cells are structurally and functionally analogous to cochlear hair cells but are optically and pharmacologically accessible within an intact specimen, making the zebrafish a good model in which to study hair-cell mitochondrial activity. Moreover, the ease of genetic manipulation of zebrafish embryos allows for the study of mutations implicated in human deafness, as well as the generation of transgenic models to visualize mitochondrial calcium transients and mitochondrial activity in live organisms. Studies of the zebrafish lateral line have shown that variations in mitochondrial activity can predict hair-cell susceptibility to damage by aminoglycosides or noise exposure. In addition, antioxidants have been shown to protect against noise trauma and ototoxic drug–induced hair-cell death. In this review, we discuss the tools and findings of recent investigations into zebrafish hair-cell mitochondria and their involvement in cellular processes, both under homeostatic conditions and in response to noise or ototoxic drugs. The zebrafish lateral line is a valuable model in which to study the roles of mitochondria in hair-cell pathologies and to develop therapeutic strategies to prevent sensorineural hearing loss in humans.

scholarly journals Sensorineural Hearing Loss Due to Exposure of Noisy Trains on Populations Around Turirejo Train Railroad Cross

2020 ◽  
Vol 12 (1) ◽  
pp. 59
Author(s):  
Diana Kusuma Wardhani ◽  
Jojok Mukono Mukono
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Hair Cells ◽  
Noise Intensity ◽  
Noise Exposure ◽  
Sound Level ◽  
Sensorineural Hearing ◽  
High Noise ◽  
Railroad Tracks ◽  
The Government

Introduction: As one of the preferred modes of land transportation, the frequency of train services was very high. One of the negative impacts arising from train activity was noise. The high noise intensity of the train causes hearing loss. Method: This study aims to analyze the differences in the incidence of hearing loss in 2 groups of residents in Turirejo Lawang Malang. This research used the observational method and the data were analyzed descriptive qualitative. A total of 20 people were selected as respondents by purposive sampling. Noise intensity was measured by Sound Level Meter and audiometric measurements were examined at SIMA Malang Laboratory. Result and Discussion: The prevalence of sensorineural hearing loss was more common in residents whose homes at 3-7 m away from the railroad tracks. In addition, residents who lived at least 15 years at a distance of 3-7 m also experienced more hearing loss. One cause of hearing loss is due to exposure to high noise and for a long time and will damage the hair cells in the cochlea, causing hearing loss. If noise exposure continues and for a long period of time damage to hair cells will be permanent and cannot return to normal. Conclusion: There needs to be a policy from the government in determining the minimum limit of the distance of the house to the railroad tracks. In addition, it is necessary to install a barrier near people’s homes to reduce noise.

scholarly journals Two novel likely pathogenic variants of HARS2 identified in a Chinese family with sensorineural hearing loss

Hereditas ◽  
2020 ◽  
Vol 157 (1) ◽  
Author(s):  
Jing Yu ◽  
Wei Jiang ◽  
Li Cao ◽  
Xiaoxue Na ◽  
Jiyun Yang
Keyword(s):  
Hearing Loss ◽  
Sensorineural Hearing Loss ◽  
Motor Development ◽  
Sensorineural Hearing ◽  
Chinese Family ◽  
Targeted Next Generation Sequencing ◽  
Gross Motor Development ◽  
Pathogenic Variants ◽  
Perrault Syndrome ◽  
Ear Malformations

AbstractMutations in HARS2 are one of the genetic causes of Perrault syndrome, characterized by sensorineural hearing loss (SNHL) and ovarian dysfunction. Here, we identified two novel putative pathogenic variants of HARS2 in a Chinese family with sensorineural hearing loss including two affected male siblings, c.349G > A (p.Asp117Asn) and c.908 T > C (p.Leu303Pro), through targeted next-generation sequencing methods. The two affected siblings (13 and 11 years old) presented with early-onset, rapidly progressive SNHL. The affected siblings did not have any inner ear malformations or delays in gross motor development. Combined with preexisting clinical reports, Perrault syndrome may be latent in some families with non-syndromic deafness associated with HARS2 mutations. The definitive diagnosis of Perrault syndrome based on clinical features alone is a challenge in sporadic males, and preadolescent females with no signs of POI. Our findings further expanded the existing spectrum of HARS2 variants and Perrault syndrome phenotypes, which will assist in molecular diagnosis and genetic counselling of patients with HARS2 mutations.

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