Genetic variations in protocadherin 15 and their interactions with noise exposure associated with noise-induced hearing loss in Chinese population

Interactions of genetic variations in FAS, GJB2 and PTPRN2 are associated with noise-induced hearing loss: a case-control study in China

BACKGROUND

This study aimed to screen and validate noise-induced hearing loss (NIHL) associated single nucleotide polymorphisms (SNPs), construct genetic risk prediction models, and evaluate higher-order gene-gene, gene-environment interactions for NIHL in Chinese population.

METHODS

First, 83 cases and 83 controls were recruited and 60 candidate SNPs were genotyped. Then SNPs with promising results were validated in another case-control study (153 cases and 252 controls). NIHL-associated SNPs were identified by logistic regression analysis, and a genetic risk model was constructed based on the genetic risk score (GRS), and classification and regression tree (CART) analysis was used to evaluate interactions among gene-gene and gene-environment.

RESULTS

Six SNPs in five genes were significantly associated with NIHL risk (p < 0.05). A positive dose-response relationship was found between GRS values and NIHL risk. CART analysis indicated that strongest interaction was among subjects with age ≥ 45 years and cumulative noise exposure ≥ 95 [dB(A)·years], without personal protective equipment, and carried GJB2 rs3751385 (AA/AB) and FAS rs1468063 (AA/AB) (OR = 10.038, 95% CI = 2.770, 47.792), compared with the referent group. CDH23, FAS, GJB2, PTPRN2 and SIK3 may be NIHL susceptibility genes.

CONCLUSION

GRS values may be utilized in the evaluation of the cumulative effect of genetic risk for NIHL based on NIHL-associated SNPs. Gene-gene, gene-environment interaction patterns play an important role in the incidence of NIHL.

The association of genetic polymorphisms in protocadherin 15 with sudden sensorineural hearing loss in a Chinese population

BACKGROUND

Sudden sensorineural hearing loss (SSNHL) is a multifactorial disease, and its etiology is still unknown. SSNHL may be caused by environmental factors and genetic changes. PCDH15 is associated with susceptibility to hearing loss. The relationship between PCDH15 and SSNHL remains unknown.

METHODS

In this study, the potential association between PCDH15 polymorphism and SSNHL in Chinese population was evaluated. Two single nucleotide polymorphisms PCDH15-rs7095441 and rs11004085 in 195 SSNHL patients and 182 healthy controls were determined by TaqMan technology.

RESULTS

In Chinese population, the TT genotype and T allele of rs7095441 are associated with increased susceptibility to SSNHL. The relationships between rs7095441 and the degree of hearing loss were analyzed, and TT genotype increased the risk of hearing loss. Among SSNHL patients, patients with TT genotype of rs7095441 have an increased risk of vertigo.

CONCLUSION

This study found that the TT genotype of SNP rs7095441 can increase the risk of SSNHL in Chinese population.

The Role of Genetic Variants in the Susceptibility of Noise-Induced Hearing Loss

Noised-induced hearing loss (NIHL) is an acquired, progressive neurological damage caused by exposure to intense noise in various environments including industrial, military and entertaining settings. The prevalence of NIHL is much higher than other occupational injuries in industrialized countries. Recent studies have revealed that genetic factors, together with environmental conditions, also contribute to NIHL. A group of genes which are linked to the susceptibility of NIHL had been uncovered, involving the progression of oxidative stress, potassium ion cycling, cilia structure, heat shock protein 70 (HSP70), DNA damage repair, apoptosis, and some other genes. In this review, we briefly summarized the studies primary in population and some animal researches concerning the susceptible genes of NIHL, intending to give insights into the further exploration of NIHL prevention and individual treatment.

Intermittent white noise exposure is associated with rat cochleae damage and changes in the gene expression

Background

Noise, a physical factor in most work environments, has many effects on human health. Exposure to excessive noise can modify the expression of associated genes with NIHL. The aim of this study to elucidate changes in expression of GJB2 and SLC26A4 after exposure to intense noise which are the most frequent causing genes to apparent autosomal recessive non-syndromic hearing loss.

Methods

In this experimental and case–control study, 17 male Wistar rats were randomly divided into exposure groups (n = 12) and without exposure (n = 5). First group was exposed to noise (90–120 dB, 70 Hz–16 kHz, 8 h/day) for 3–6 days. Cochlear biopsies performed 1 h and 1 week post-exposure, relative gene expression levels were calculated using $${2}^{-\Delta \Delta Ct}$$ 2 - Δ Δ C t . From each group, one ear was stained by hematoxylin and eosin method for histopathological survey. Real-time PCR technique took place, and gene expression data were normalized by GAPDH gene. One-way ANOVA test was performed with a significance level of 0.05 by GraphPad prism software.

Results

Both GJB2 and SLC26A4 in all groups were down-regulated after exposure compared to their controls. Fold changes in the highest times were related to 1 week after 6 days of exposure, 0.052 and 0.015, respectively. Serious damages occurred in different parts of cochlea, and they were more severe after 6 days and 1-week later.

Conclusion

It is expected that if the hearing threshold tests be performed before/after exposure and considering longer post-exposure times, subsequently, the expression of these genes does not return to basal level, and irrecoverable damage to the cochlea, progressive and irreversible ARNSHL will be expected.

Noise Damage Accelerates Auditory Aging and Tinnitus: A Canadian Population-Based Study

OBJECTIVE

Age-related hearing loss (ARHL) is the third most challenging disability in older adults. Noise is a known modifiable risk factor of ARHL, which can drive adverse health effects. Few large-scale studies, however, have shown how chronic noise exposure (CNE) impacts the progression of ARHL and tinnitus.

STUDY DESIGN

Retrospective large-scale study.

SETTING

Audiology clinical practice.

PATIENTS

In this study, 928 individuals aged 30-100 years without (n=497) or with the experience of CNE (n=431) were compared in their hearing assessments and tinnitus. In order to only investigate the impact of CNE on ARHL and tinnitus, people with other risk factors of hearing loss were excluded from the study.

INTERVENTION

Diagnostic.

MAIN OUTCOME MEASURES

Noise damage was associated with a greater ARHL per age decades (pure-tone average(PTA)0.5-4kHz alterations 19.6-70.8 dB vs. 8.0-63.2 dB, ≤0.001), an acceleration of developing a significant ARHL at least by two decades (PTA0.5-4kHz 33.4 dB at 50-59yr vs. 28.2 dB at 30-39yr, ≤0.001), and an increased loss of word recognition scores (total average 84.7% vs. 80.0%, ≤0.001). Significant noise-associated growth in the prevalence of tinnitus also was shown, including more than a triple prevalence for constant tinnitus (28.10% vs. 8.85%, ≤0.001) and near to a double prevalence for intermittent tinnitus (19.10% vs. 11.10%, ≤0.001). Noise also resulted in the elevation of the static compliance of the tympanic membrane throughout age (total average 0.61 vs. 0.85 mmho, ≤0.001).

CONCLUSIONS

Our findings emphasize the significant contribution of CNE in auditory aging and the precipitation of both ARHL and tinnitus.

Role of CASP7 polymorphisms in noise-induced hearing loss risk in Han Chinese population

Genetic factors and gene-environment interaction may play an important role in the development of noise induced hearing loss (NIHL). 191 cases and 191 controls were selected by case–control study. Among them, case groups were screened from workers exposed to noise in binaural high-frequency hearing thresholds greater than 25 dB (A). Workers with hearing thresholds ≤ 25 dB (A) in any binaural frequency band were selected to the control group, based on matching factors such as age, exposure time to noise, and operating position. The blood samples from two groups of workers were subjected to DNA extraction and SNP sequencing of CASP3 and CASP7 genes using the polymerase chain reaction ligase detection reaction method. Conditional logistic regression correction was used to analyze the genetic variation associated with susceptibility to NIHL. There was an association between rs2227310 and rs4353229 of the CASP7 gene and the risk of NIHL. Compared with the GG genotype, the CC genotype of rs2227310 reduced the risk of NIHL. Compared with CC genotype, the TT genotype of rs4353229 reduced the risk of NIHL. Workers carrying the rs2227310GG and rs4353229CC genotype had an increased risk of NIHL compared to workers without any high-risk genotype. There were additive interaction and multiplication interaction between CASP7rs2227310 and CNE, and the same interaction between CASP7rs4353229 and CNE. The interaction between the CASP7 gene and CNE significantly increased the risk of NIHL. The genetic polymorphisms of CASP7rs2227310GG and CASP7rs4353229CC were associated with an increased risk of NIHL in Han Chinese population and have the potential to act as biomarkers for noise-exposed workers.

Effect of myricetin on the gene expressions of NOX3, TGF-β1, prestin, and HSP-70 and anti-oxidant activity in the cochlea of noise-exposed rats

Objective(s):

Noise-induced hearing loss is one of the most common occupational diseases in industrialized countries and can be affected by various environmental and genetic factors. This study was designed to examine the effect of myricetin in preventing this disorder.

Materials and Methods:

Twenty-one Wistar rats were randomly divided into five groups: Non-exposed, noise exposure only, noise exposure with vehicle, noise exposure with myricetin 5 mg/Kg, and noise exposure with myricetin 10 mg/kg. All animals were sacrificed after last noise exposure. The left cochlea was dissected from each rat. It was used for mRNA expression analysis (NOX3, TGF-β1, prestin, and HSP-70). Blood samples were collected to assess superoxide dismutase (SOD) activity, 1, 1 diphenyl picrylhydrazyl (DPPH), and malondialdehyde (MDA) measurements.

Results:

Real time-PCR assay revealed that noise decreased NOX3 and increased TGF-β1, prestin, and HSP-70 gene expressions. Administration of myricetin at the dose of 5 mg/kg, but not at 10 mg/kg, significantly reversed these changes. Noise also increased MDA levels and decreased SOD and DPPH scavenging activities. Myricetin at the doses of 5 and 10 mg/kg also reversed these changes.

Conclusion:

The findings of this study showed that myricetin at the dose of 5 mg/Kg was able to reverse noise-induced abnormalities in gene expression and oxidant/anti-oxidant balance. It is a possibility that myricetin via enhancement of anti-oxidant activity induced these effects.

Association of intronic polymorphisms (rs1549339, rs13402242) and mRNA expression variations in PSMD1 gene in arsenic-exposed workers

Ubiquitin-proteasome system (UPS) gene, PSMD1, is an important gene for neutralization of damaged and misfolded protein(s). The current study was designed to study the genetic and expression variations of PSMD1 gene as a consequence of arsenic exposure and its potential implications in arsenic induced diseases. In the present study, 250 blood samples of exposed industrial workers along with 250 controls were used. Initially, tetra amplification refractory mutation system-PCR was used to determine the role of PSMD1 gene polymorphisms (rs1549339, rs13402242) in industrial workers and controls. Frequency of homozygous mutant genotype of rs1549339 (OR: 2.23, 95% CI: 1.51-3.32, p = 0.0001) and rs13402242 (OR: 2.96, 95% CI: 1.52-5.75, p = 0.001) was observed significantly higher in exposed individuals vs controls. Secondly, qPCR was performed for expression analysis of PSMD1 gene. Significant down-regulated expression of PSMD1 gene (p < 0.0001) was observed vs controls, and this down-regulation was observed more pronounced in smokers (p < 0.0001) with maximum exposure duration (p < 0.0008). This down-regulated expression was observed significantly more pronounced in welding (p < 0.004) and brick kiln industries (p < 0.04) compared to other selected industries. The obtained results suggest that the exposure to arsenic may have an increased risk of developing disease(s) because of arsenic-induced PSMD1 variations.

What is noise-induced hearing loss?

Noise-induced hearing loss is sensory deafness caused by long-term exposure of the auditory system to a noisy environment. Auditory fatigue is an early symptom of noise-induced hearing loss, and hearing can gradually recover after people leave a noisy environment. However, if people remain in a noisy environment for a prolonged period of time, their hearing will be permanently impaired. Societal changes mean that people are more likely to be exposed to noise. The hearing loss and tinnitus caused by noise seriously affect people's quality of life and lead to huge economic loss. The pathogenesis of noise-induced hearing loss is complex. Various theories try to explain this, such as the oxidative stress theory, but none perfectly explains the occurrence of noise-induced hearing loss. There is no treatment which can completely reverse the damage. More research is required to explore the pathogenesis and to better guide clinical practice. Preventative strategies, such as educating the public about hearing health, should be adopted to reduce the harm of noise-induced hearing loss.

Diseases of the ear

In children with normal hearing, inflammatory disorders caused by infections of the middle ear (otitis media) are the most common ear illnesses. Many of older adults experience some level of hearing loss. Several factors can lead to either a partial loss or the total inability to hear (deafness) including exposure to noise, a hereditary predisposition, chronic infections, traumas, medications, and aging.

An overview of research trends and genetic polymorphisms for noise-induced hearing loss from 2009 to 2018

Recently, there has been increased studies in noise-induced hearing loss (NIHL). We aimed to make an overview of research trends and genetic polymorphisms for NIHL from 2009 to 2018 with VOSviewer software. A total of 2391 papers were identified for research trends analysis in NIHL and 33 studies identified for a brief review of genetic polymorphisms in human NIHL. The number of publications has been increasing over the past decade. The journal Hearing Research published the most articles (218). The USA contributed the largest number of papers (1042; 43.58%), with the most citations (18,987) and the highest H-index (60). The University of Washington was the most contributive institution. Liberman MC published the most articles (32), and Kujawa SG possessed the highest co-citations (584). Except for high-frequency keywords identified by the software, "prevalence," "oxidative stress," "hair cells," and "cochlear implant" were also the latest research frontiers. HSPA1A rs1043618, HSPA1L rs2227956, PON2 rs12026 and rs7785846, SOD2 rs2855116, KCNE1 rs2070358, KCNQ4 rs34287852, GJB2 rs3751385, PCDH15 rs7095441 and rs11004085, GRHL2 rs1981361, ITGA8 rs10508489, MYH14 rs667907, and POU4F3 rs891969 were the research hotspots and were replicated in independent samples. Inflammation response underlying NIHL has emerged and should be considered as a pioneering field in the future for the prevention of NIHL and conservation of hearing.

Screening of noise-induced hearing loss (NIHL)-associated SNPs and the assessment of its genetic susceptibility

BACKGROUND

The aim of this study was to screen for noise-induced hearing loss (NIHL)-associated single nucleotide polymorphisms (SNPs) and to construct genetic risk prediction models for NIHL in a Chinese population.

METHODS

Four hundred seventy-six subjects with NIHL and 476 matched controls were recruited from a cross-sectional survey on NIHL in China. A total of 83 candidate SNPs were genotyped using nanofluidic dynamic arrays on a Fluidigm platform. NIHL-associated SNPs were screened with a multiple logistic model, and a genetic risk model was constructed based on the genetic risk score (GRS). The results were validated using a prospective cohort population.

RESULTS

Seven SNPs in the CDH23, PCDH15, EYA4, MYO1A, KCNMA1, and OTOG genes were significantly (P < 0.05) associated with the risk of NIHL, whereas seven other SNPs were marginally (P > 0.05 and P < 0.1) associated with the risk of NIHL. A positive correlation was observed between GRS values and odds ratio (OR) for NIHL. Two SNPs, namely, rs212769 and rs7910544, were validated in the cohort study. Subjects with higher GRS (≧9) showed a higher risk of NIHL incidence with an OR of 2.00 (95% CI = 1.04, 3.86).

CONCLUSIONS

Genetic susceptibility plays an important role in the incidence of NIHL. GRS values, which are based on NIHL-associated SNPs. GRS may be utilized in the evaluation of genetic risk for NIHL and in the determination of NIHL susceptibility.

[The genetic aspects of occupational hearing impairment]

This article was designed to be the overview of the current literature publications concerning the identification of the genetic markers of susceptibility to the noise-induced loss of hearing. The analysis of these data has demonstrated that the major gene polymorphisms associated with the development of this pathological condition are localized in the genes encoding for the antioxidant systems, potassium homeostasis, and adhesion molecules as well as in the genes involved in intercellular coupling, the mechanisms underlying the cellular response to stress, activation and regulation of heat shock proteins, and signaling function of the immune system. It is concluded that the further investigations into the genetic aspects of the full-genome sequencing techniques and the search for genomic associations could greatly contribute to the development of personalized medicine and the reduction of risks of occupational noise-induced sensorineural impairment of hearing.

Noise exposure in occupational setting associated with elevated blood pressure in China

Background

Hypertension is the primary out-auditory adverse outcome caused due to occupational noise exposure. This study investigated the associations of noise exposure in an occupational setting with blood pressure and risk of hypertension.

Methods

A total of 1,390 occupational noise-exposed workers and 1399 frequency matched non-noise-exposed subjects were recruited from a cross-sectional survey of occupational noise-exposed and the general population, respectively. Blood pressure was measured using a mercury sphygmomanometer following a standard protocol. Multiple logistic regression was used to calculate the odds ratio (OR) and 95% confidence interval (CI) of noise exposure adjusted by potential confounders.

Results

Noise-exposed subjects had significantly higher levels of systolic blood pressure(SBP) (125.1 ± 13.9 mm Hg) and diastolic blood pressure (DBP) (77.6 ± 10.7 mm Hg) than control subjects (SBP: 117.2 ± 15.7 mm Hg, DBP: 70.0 ± 10.5 mm Hg) (P < 0.001). Significant correlations were found between noise exposure and blood pressure (SBP and DBP) (P < 0.001). However, the linear regression coefficients with DBP appeared larger than those with SBP.

The prevalence of hypertension was 17.8% in subjects with noise exposure and 9.0% in control group (P < 0.001). Compared with the control group, the subjects with noise exposure had the risk of hypertension with an OR of 1.941 (95% CI = 1.471– 2.561) after adjusting for age, sex, smoking, and drinking status. Dose–response relationships were found between noise intensity, years of noise exposure, cumulative noise exposure and the risk of hypertension (all P values < 0.05). No significant difference was found between subjects wearing an earplug and those not wearing an earplug, and between steady and unsteady noise categories (P > 0.05).

Conclusions

Occupational noise exposure was associated with higher levels of SBP, DBP, and the risk of hypertension. These findings indicate that effective and feasible measures should be implemented to reduce the risk of hypertension caused by occupational noise exposure.

Associations of genetic variations in EYA4, GRHL2 and DFNA5 with noise-induced hearing loss in Chinese population: a case- control study

BACKGROUND

Both environmental and genetic factors are attributable to the incidence of noise-induced hearing loss (NIHL). The purpose of this study was to examine the associations between genetic variations in the EYA4, GRHL2 and DFNA5 genes and the risk to noise-induced hearing loss (NIHL) in a Chinese population.

METHODS

A case-control study was conducted with 476 NIHL workers and 475 normal hearing workers matched with gender, years of noise exposure, and intensity of noise exposure. Twelve tag single-nucleotide polymorphisms (SNP) in the EYA4, GRHL2 and DFNA5 genes were genotyped using nanofluidic dynamic arrays on the Fluidigm platform. Multiple logistic regression was used to analyze the associations of genetic variations with NIHL adjusted by age, smoking/drinking status, and cumulative noise exposure and their interactions with noise exposure.

RESULTS

The SNPs of rs3777781and rs212769 in the EYA4 gene were significantly associated with NIHL risk. In rs3777781, comparing with the subjects carrying with TT types, the carriers with AT and AA genotypes had the decreased risk of NIHL (OR = 0.721, 95% CI = 0.522 - 0.996). In rs212769, the AG and AA carriers had increased NIHL risk (OR = 1.430, 95% CI = 1.014 - 2.016) compared with the subjects with GG genotype. Rs666026 in the associated GRHL2 gene and rs2521758 in the DFNA5 gene were marginally t associated with NIHL (P = 0.065 and 0.052, respectively). Rs2521758 and rs212769 had significantly interacted with noise exposure (P < 0.05).

CONCLUSIONS

Genetic variations in the EYA4, GRHL2 and DFNA5 genes and their interactions with occupational noise exposure may play an important role in the incidence of NIHL.