Association of genetic variations in FOXO3 gene with susceptibility to noise induced hearing loss in a Chinese population

Integrating pharmacogenomics into clinical trials of hearing disorders

In 2019, the U.S. Food and Drug Administration issued guidance to increase the efficiency of drug development and support precision medicine, including tailoring treatments to those patients who will benefit based on genetic variation even in the absence of a documented mechanism of action. Although multiple advancements have been made in the field of pharmacogenetics (PGx) for other disease conditions, there are no approved PGx guidelines in the treatment of hearing disorders. In studies of noise-induced hearing loss (NIHL), some progress has been made in the last several years associating genomic loci with susceptibility to noise damage. However, the power of such studies is limited as the underlying physiological responses may vary considerably among the patient populations. Here, we have summarized previous animal studies to argue that NIHL subtyping is a promising strategy to increase the granularity of audiological assessments. By coupling this enhanced phenotyping capability with genetic association studies, we suggest that drug efficacy will be better predicted, increasing the likelihood of success in clinical trials when populations are stratified based on genetic variation or designed with multidrug combinations to reach a broader segment of individuals suffering or at risk from NIHL.

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.

Association between UBAC2 gene polymorphism and the risk of noise-induced hearing loss: a cross-sectional study

The purpose of this article was to investigate the association between the ubiquitin-associated domain-containing protein 2 (UBAC2) gene polymorphism and noise-induced hearing loss (NIHL) and to further explore the role of single-nucleotide polymorphism (SNP) in UBAC2 in NIHL. A case control study involving 660 NIHL cases and 581 controls was conducted in this research. After genotyping by multiplex polymerase chain reaction (PCR) with next-generation sequencing, the correlation between SNPs and NIHL was analyzed using logistic regression analysis. Haplotype analysis was performed by Haploview 4.1 software. Then luciferase reporter assays and siRNA were used to explore the mechanism of SNPs in UBAC2 affecting NIHL susceptibility. The correlation analysis showed that rs3825427 AA genotype, rs9517701 GG genotype, rs7999348 GG genotype, and rs2296860 AA genotype were all associated with increased risk of NIHL (P < 0.05). The haplotype AGGA (rs3825427-rs9517701-rs7999348-rs2296860) also had a higher risk of NIHL (OR = 1.314; 95% CI, 1.098-1.572; P = 0.003). The results of the luciferase reporter assays showed that the fluorescence intensity of CTCF-OE + UBAC2 WT + TK was significantly higher than that of CTCF-NC + UBAC2 WT + TK and CTCF-OE + UBAC2 MT + TK (all P < 0.01). In CTCF knockdown cells, the expression of UBAC2 was also significantly downregulated (P = 0.0038), indicating that the transcription factor CTCF positively regulated the expression of UBAC2 and the rs3825427 C allele acted as an enhancer, which can promote CTCF to bind to the promoter of UBAC2, thereby promoting transcription. UBAC2 gene polymorphism is related to NIHL susceptibility. The UBAC2 rs3825427 regulates the expression level of UBAC2 by affecting the combination of CTCF and DNA, thus affecting the susceptibility of NIHL.

A combined genome-wide association and molecular study of age-related hearing loss in H. sapiens

BACKGROUND

Sensorineural hearing loss is one of the most common sensory deficiencies. However, the molecular contribution to age-related hearing loss is not fully elucidated.

METHODS

We performed genome-wide association studies (GWAS) for hearing loss-related traits in the UK Biobank (N = 362,396) and selected a high confidence set of ten hearing-associated gene products for staining in human cochlear samples: EYA4, LMX1A, PTK2/FAK, UBE3B, MMP2, SYNJ2, GRM5, TRIOBP, LMO-7, and NOX4.

RESULTS

All proteins were found to be expressed in human cochlear structures. Our findings illustrate cochlear structures that mediate mechano-electric transduction of auditory stimuli, neuronal conductance, and neuronal plasticity to be involved in age-related hearing loss.

CONCLUSIONS

Our results suggest common genetic variation to influence structural resilience to damage as well as cochlear recovery after trauma, which protect against accumulated damage to cochlear structures and the development of hearing loss over time.

A functional SNP in miR-625-5p binding site of AKT2 3'UTR is associated with noise-induced hearing loss susceptibility in the Chinese population

The purposes of the current study were to investigate the association of a few of single nucleotide polymorphisms (SNPs) within the AKT2 gene and noise-induced hearing loss (NIHL) susceptibility and explore the potential mechanism underlying NIHL. Three SNPs (rs2304186, rs41275750, and rs76524493) were genotyped in a Chinese population which consists of 690 NIHL patients and 650 normal hearing controls. Bioinformatic analysis was conducted to predict the potential miRNA-binding site of SNPs. Plasmid construction, cell transfection, and dual-luciferase reporter assay were performed to investigate the potential molecular mechanism of SNPs involving in NIHL. The results revealed that rs2304186 GT genotype (OR = 1.41; 95% CI = 1.09-1.83) and TT genotype (OR = 1.51; 95% CI = 1.08-2.10) imparted increased risk of NIHL, and the increased risk could also be found in a dominant model (OR = 1.44; 95% CI = 1.12-1.84). The stratification analysis showed that rs2304186 GT/TT conferred a higher risk for NIHL, especially in subgroups of male, age (35-45 and > 45 years), noise exposure time (> 16 years), and noise exposure level (≤ 85 and ≥ 92 dB), when GG genotype as a reference. Furthermore, the haplotype TCCTACT (rs2304186-rs41275750-rs76524493) was found to be significantly associated with a high risk of NIHL (OR = 1.19; 95% CI = 1.02-1.40). Functional experiments showed that rs2304186 G allele combined with hsa-miR-625-5p mimics could significantly decrease the luciferase activity compared with T allele, indicating that rs2304186 altered the binding affinity of hsa-miR-625-5p to SNP rs2304186 mutation region, thus directly targeting AKT2 gene. In conclusion, our study provides evidence for the first time that SNP rs2304186 of AKT2 3'UTR might affect NIHL susceptibility by altering the binding affinity of has-miR-625-5p to mutation region in an allele-specific manner and it may act as a potential biomarker of NIHL susceptibility.

Primed to die: an investigation of the genetic mechanisms underlying noise-induced hearing loss and cochlear damage in homozygous Foxo3-knockout mice

The prevalence of noise-induced hearing loss (NIHL) continues to increase, with limited therapies available for individuals with cochlear damage. We have previously established that the transcription factor FOXO3 is necessary to preserve outer hair cells (OHCs) and hearing thresholds up to two weeks following mild noise exposure in mice. The mechanisms by which FOXO3 preserves cochlear cells and function are unknown. In this study, we analyzed the immediate effects of mild noise exposure on wild-type, Foxo3 heterozygous (Foxo3+/-), and Foxo3 knock-out (Foxo3-/-) mice to better understand FOXO3's role(s) in the mammalian cochlea. We used confocal and multiphoton microscopy to examine well-characterized components of noise-induced damage including calcium regulators, oxidative stress, necrosis, and caspase-dependent and caspase-independent apoptosis. Lower immunoreactivity of the calcium buffer Oncomodulin in Foxo3-/- OHCs correlated with cell loss beginning 4 h post-noise exposure. Using immunohistochemistry, we identified parthanatos as the cell death pathway for OHCs. Oxidative stress response pathways were not significantly altered in FOXO3's absence. We used RNA sequencing to identify and RT-qPCR to confirm differentially expressed genes. We further investigated a gene downregulated in the unexposed Foxo3-/- mice that may contribute to OHC noise susceptibility. Glycerophosphodiester phosphodiesterase domain containing 3 (GDPD3), a possible endogenous source of lysophosphatidic acid (LPA), has not previously been described in the cochlea. As LPA reduces OHC loss after severe noise exposure, we treated noise-exposed Foxo3-/- mice with exogenous LPA. LPA treatment delayed immediate damage to OHCs but was insufficient to ultimately prevent their death or prevent hearing loss. These results suggest that FOXO3 acts prior to acoustic insult to maintain cochlear resilience, possibly through sustaining endogenous LPA levels.

Noise-Induced Hearing Loss: Updates on Molecular Targets and Potential Interventions

Noise overexposure leads to hair cell loss, synaptic ribbon reduction, and auditory nerve deterioration, resulting in transient or permanent hearing loss depending on the exposure severity. Oxidative stress, inflammation, calcium overload, glutamate excitotoxicity, and energy metabolism disturbance are the main contributors to noise-induced hearing loss (NIHL) up to now. Gene variations are also identified as NIHL related. Glucocorticoid is the only approved medication for NIHL treatment. New pharmaceuticals targeting oxidative stress, inflammation, or noise-induced neuropathy are emerging, highlighted by the nanoparticle-based drug delivery system. Given the complexity of the pathogenesis behind NIHL, deeper and more comprehensive studies still need to be fulfilled.

Polymorphisms in the FAS gene are associated with susceptibility to noise-induced hearing loss

This study investigated the relationship between genetic polymorphisms in the FAS gene and noise-induced hearing loss (NIHL) risk among Chinese workers exposed to occupational noise, and the molecular mechanism of NIHL caused by noise. In this case-control study, 692 NIHL workers and 650 controls were selected for genotyping of four single nucleotide polymorphisms (SNPs) of the FAS gene. Logistic regression was used to calculate the odds ratio (OR) and 95% confidence interval (CI) of the association of these genetic polymorphisms and NIHL. At the same time, a noise-exposed rat model was constructed to further clarify the effect of noise exposure on fas gene expression and the pathogenic mechanism of NIHL. Two polymorphisms, rs1468063 and rs2862833, were associated with NIHL in the case-control study. Individuals with the rs1468063-TT or rs2862833-AA genotypes had decreased NIHL risk (p < 0.01, p = 0.02, respectively). Compared with the control group, the hearing threshold of the case group of rats increased, while serum MDA, urine 8-OHdG, and fas gene expression increased, but let-7e expression decreased. Genetic polymorphisms in the FAS gene are related to the risk of NIHL in the Chinese population. Noise can cause a large amount of reactive oxygen species (ROS) in the cochlea tissue and blood, which lead to oxidative stress, lipid peroxidation, and DNA damage, further activating the FAS gene, and ultimately leading to hearing loss.

Variations in the potassium voltage-gated channel subfamily E regulatory subunit 1 gene associated with noise-induced hearing loss in the Chinese population

Noise-induced hearing loss (NIHL) is one of the most common occupational health risks in industrialized countries. It has been recognized to result from interactions between genetic and environmental factors. This study investigated the influence of genetic mutations in the potassium voltage-gated channel subfamily E regulatory subunit 1 (KCNE1) gene on susceptibility to NIHL. A total of 2689 industrial workers in eastern China were recruited to participate. Three single-nucleotide polymorphisms (SNPs) of KCNE1 were genotyped in noise-exposed workers who were classified into 589 cases and 639 control individuals. Then, main effects of the genotypes and their interactions with environmental factors were evaluated. Results showed that the rs3453 C allele located in KCNE1 3'-UTR region and the rs1805127 G allele in the encoding region were associated with increased risk of NIHL in the Chinese population. There is an association between TAA, TAG, and other (CAA/CGA) haplotypes (rs3453-rs11702354-rs1805127) and increased risk of NIHL with OR = 1.33, 1.43, and 2.93 (P = 0.022, 0.017, and 0.001 respectively) compared with CGG group. Results also showed a significant interaction between rs3453, rs1805127, and high-temperature exposure (P = 0.0002, adjusted OR = 1.85). The cellular evidence indicated that polymorphisms rs3453 and rs1805127 may play key roles in hearing loss through affecting KCNE1 expressions by the way of microRNA and protein respectively. The further animal study is still needed to confirm these mechanisms. KCNE1 rs3453 and rs1805127 may have a potential as biomarkers for screening the susceptibility to NIHL.

Research and Discussion on the Relationships between Noise-Induced Hearing Loss and ATP2B2 Gene Polymorphism

Long-term and continuous noise exposure can result in noise-induced hearing loss (NIHL), which is a worldwide problem resulting from the interaction of environmental and genetic factors. The ATP2B2 gene polymorphism can destroy cochlear hair cells and increase the risk of NIHL. A case-control study of 760 Chinese textile workers was conducted to investigate the relationship between ATP2B2 polymorphisms and NIHL susceptibility. Venous blood was collected and questionnaires were conducted by professional physicians. A case group and a control group which were typed by individuals' pure-tone audiometry test results were set. Three polymorphism sites of ATP2B2 were genotyped by using the PCR technique. Analysis results revealed that the C allele of rs3209637 (95%CI = 1.08-2.58, odds ratio (OR) = 1.67, P = 0.027) was a dangerous factor and could add to risks of NIHL in the Chinese employees. The data of stratified analysis revealed that individuals who are exposed to noise > 95 dB with the rs3209637 C genotype have a higher susceptibility to NIHL (OR = 1.34, 95%CI = 1.07-1.68). Multifactor dimensionality reduction analysis revealed that the interaction between rs14154 and rs3209637 is linked to increased NIHL risk, and for the interaction among rs14154, smoking and drinking had the same function (OR = 1.54 and 1.77, 95%CI = 1.15-2.07, 1.33-2.37, and P = 0.0037 and P < 0.0001, respectively). Our results suggest that genetic polymorphism rs3209637 C within ATP2B2 is a risk factor for NIHL among Chinese employees and rs3209637 C could be a potential biomarker for NIHL patients.

Analysis of Polymorphisms Associated with Base Excision Repair in Patients Susceptible and Resistant to Noise-Induced Hearing Loss

Objective

Noise-induced hearing loss (NIHL) is one of the most common occupational health risks in both developed and industrialized countries. It occurs as a result of interactions between genetic and environmental factors. Nevertheless, inherited genetic factors contributing to NIHL are not well understood. Therefore, we aim to investigate whether genetic mutations in three important base excision repair genes (OGG1, APEX1, and XRCC1) may influence susceptibility to NIHL.

Methods

Three SNPs in OGG1, APEX1, and XRCC1 were genotyped from 1170 noise-exposed workers and were classified into 117 most susceptible and 117 most resistant individuals.

Results

Results showed that the rs1799782 TT genotype located in the XRCC1 coding region and rs1130409 GG/GT in the APEX1 coding region were associated with increased risk for NIHL in a Chinese population. Compared to the rs1799782 C allele frequency, the T allele frequency was increased in the sensitive group (adjusted OR = 1.51, 95%CI = 1.01 to 2.26, P = 0.043). The rs1130409 G allele frequency was also increased in the sensitive group compared to the resistant group (adjusted OR = 1.59, 95%CI = 1.10 to 2.31, P = 0.015). Moreover, rs1130409 and drinking had a statistically significant interaction (P = 0.0002), while rs1799782, rs1130409, and smoking also had a statistically significant interaction (P < 0.0001).

Conclusions

XRCC1 rs1799782 and APEX1 rs1130409 may have potential as biomarkers for the screening of susceptibility to NIHL in workers exposed severe noise.

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.

Genetic variation in KCNQ4 gene is associated with susceptibility to noise-induced hearing loss in a Chinese population

Noise-induced hearing loss (NIHL), one of the most widespread occupational health risks worldwide, is a kind of complex disorder resulting from both genetic and environmental factors. KCNQ4 channels are crucial to the internal ear potassium recycling. To explore whether KCNQ4 polymorphism is associated with individual susceptibility to NIHL, we performed this genetic association study on 571 NIHL cases and 639 normal hearing controls selected from about 2700 Chinese noise-exposed workers. General information and audiometric data were obtained through questionnaires and pure-tone audiometry (PTA). DNA samples were collected and genotyping for three selected SNPs (rs709688, rs2769256 and rs4660468) was performed. Significant differences were observed between cases and controls for the genotype frequency and allele frequency in rs4660468, suggesting that rs4660468 CT/TT genotype and T allele may be risk factors for NIHL. In subjects exposed to noise for more than 16 years (OR = 1.23, 95% CI = 1.09-1.53) and those who exposed to noise >92 dB (OR = 1.29, 95% CI = 1.08-1.69), increased risks of NIHL were found after stratified analysis for rs4660468. Our results suggest that rs4660468 T allele of KCNQ4 involves with a higher risk of NIHL and could be one biomarker of susceptibility for Chinese noise exposed workers.

Notch polymorphisms associated with sensitivity of noise induced hearing loss among Chinese textile factory workers

BACKGROUND

Noise induced hearing loss (NIHL) is a polygenic disease involving both genetic and environmental factors, and is one of the most important occupational health hazards worldwide. To date, the influence of Notch1 variants on the risk to develop NIHL has not been illuminated. This study was conducted to explore the effects of Notch1 polymorphisms on individual susceptibility to NIHL.

METHODS

A total of 2689 industrial workers from one textile factory in east China were recruited to participate in the current study. Venous blood was collected, basic clinical data was obtained by questionnaires and pure-tone audiometry (PTA) tests were conducted by specialist physicians. Next we performed genotyping of three selected SNPs (rs3124594, rs3124599 and rs3124603) in the Notch1 gene in 535 NIHL patients and 535 controls. Subsequently, the main effects of the genotypes and their interactions were evaluated.

RESULTS

Our results revealed that individuals with a GG of rs3124594, TT of rs3124603 (OR = 4.70 and 1.59 respectively) and the haplotype AAC (rs3124594-rs3124599-rs3124603) (OR = 14.95) were associated with an increased risk of NIHL in our study cohort. Stratified analysis showed that an increased NIHL risk was found in individuals exposed to work related noise for ≤16 years that also had the rs3124594 GG or rs3124603 CT/TT genotype with an OR of 4.20 and 1.73 respectively. Multifactor dimensionality reduction analysis indicated that rs3124594, rs3124599 and rs3124603 interacted with each other and were related to an increased risk to develop NIHL (OR = 3.60).

CONCLUSIONS

The genetic polymorphisms rs3124594 and rs3124603 within the Notch1 gene are associated with an increased risk of NIHL in a Chinese population and could potentially be used as biomarkers for NIHL in noise exposed workers.