Xiaoyun Qian

Inhibition of ARC decreases the survival of HEI-OC-1 cells after neomycin damage in vitro

Hearing loss is a common sensory disorder mainly caused by the loss of hair cells (HCs). Noise, aging, and ototoxic drugs can all induce apoptosis in HCs. Apoptosis repressor with caspase recruitment domain(ARC) is a key factor in apoptosis that inhibits both intrinsic and extrinsic apoptosis pathways; however, there have been no reports on the role of ARC in HC loss in the inner ear. In this study, we used House Ear Institute Organ of Corti 1 (HEI-OC-1) cells, which is a cochlear hair-cell-like cell line, to investigate the role of ARC in aminoglycoside-induced HC loss. ARC was expressed in the cochlear HCs as well as in the HEI-OC-1 cells, but not in the supporting cells, and the expression level of ARC in HCs was decreased after neomycin injury in both cochlear HCs and HEI-OC-1 cells, suggesting that reduced levels of ARC might correlate with neomycin-induced HC loss. We inhibited ARC expression using siRNA and found that this significantly increased the sensitivity of HEI-OC-1 cells to neomycin toxicity. Finally, we found that ARC inhibition increased the expression of pro-apoptotic factors, decreased the mitochondrial membrane potential, and increased the level of reactive oxygen species (ROS) after neomycin injury, suggesting that ARC inhibits cell death and apoptosis in HEI-OC-1 cells by controlling mitochondrial function and ROS accumulation. Thus the endogenous anti-apoptotic factor ARC might be a new therapeutic target for the prevention of aminoglycoside-induced HC loss.

Effect of glucocorticoids on aquaporin-1 in guinea pigs with otitis media with effusion

The aim of this study was to explore the pathological changes in water homeostasis and the effects of glucocorticoids on aquaporin-1 (AQP1) in guinea pigs with otitis media with effusion (OME). Immunohistochemistry and western blotting were used to detect AQP1 in the bullae of OME models, which were induced by reversible Eustachian tube (ET) obstruction. Animals in the dexamethasone (dexa) group received dexa via intraperitoneal injection for 7 days and the pathological changes and expression patterns of AQP1 were compared with those in the OME group. In this study, 22 guinea pigs exhibited effusion 3–7 days after surgery, of which two were sacrificed. Six (60%) animals in the OME group and 9 (90%) in the dexa group presented no sign of effusion on postoperative day 14. AQP1 was detected as an 28-kDa protein in the two groups. Immunohistochemical analysis revealed that AQP1 was expressed in subepithelial fibroblasts and capillary endothelial cells. Western blot analysis revealed that the levels of AQP1 protein were markedly higher in the dexa group compared with the OME group. In conclusion, our study emphasized the significance of AQP1 in the pathophysiology of OME and suggests that glucocorticoids may regulate water homeostasis via an AQP1-regulated pathway.

Supraglottic adenoid cystic carcinoma mimicking laryngeal amyloidosis: A case report.

Supraglottic adenoid cystic carcinoma (ACC) is extremely rare and may be misdiagnosed as laryngeal amyloidosis. The present report describes a case of supraglottic ACC, which went unrecognized until histopathological examination of the neoplasm 18 months after the first presentation. The present patient presented with progressive hoarseness for half a year and initially required partial resection. Following quick regional recurrence, the patient received a total laryngectomy while refusing radiotherapy. Adjuvant post-operational traditional Chinese medicine was accepted. Over 3 years’ follow-up, there was no evidence of regional relapse or distant metastases. The present case is compared with a second case of supraglottic submucosal mass in which the signs, symptoms and examinations were similar to the first case, but that was diagnosed as laryngeal amyloidosis. Attention should be paid to submucosal masses in the larynx to prevent underlying malignancy and subsequent disease progression. Immunocytochemistry, such as p63 staining, is mandatory for making an early differential diagnosis of supraglottic ACC. Traditional Chinese medicine may be a useful adjuvant therapy for this rare disease.

Characterization of Lgr5+ Progenitor Cell Transcriptomes after Neomycin Injury in the Neonatal Mouse Cochlea.

Lgr5+ supporting cells (SCs) are enriched hair cell (HC) progenitors in the cochlea. Both in vitro and in vivo studies have shown that HC injury can spontaneously activate Lgr5+ progenitors to regenerate HCs in the neonatal mouse cochlea. Promoting HC regeneration requires the understanding of the mechanism of HC regeneration, and this requires knowledge of the key genes involved in HC injury-induced self-repair responses that promote the proliferation and differentiation of Lgr5+ progenitors. Here, as expected, we found that neomycin-treated Lgr5+ progenitors (NLPs) had significantly greater HC regeneration ability, and greater but not significant proliferation ability compared to untreated Lgr5+ progenitors (ULPs) in response to neomycin exposure. Next, we used RNA-seq analysis to determine the differences in the gene-expression profiles between the transcriptomes of NLPs and ULPs from the neonatal mouse cochlea. We first analyzed the genes that were enriched and differentially expressed in NLPs and ULPs and then analyzed the cell cycle genes, the transcription factors, and the signaling pathway genes that might regulate the proliferation and differentiation of Lgr5+ progenitors. We found 9 cell cycle genes, 88 transcription factors, 8 microRNAs, and 16 cell-signaling pathway genes that were significantly upregulated or downregulated after neomycin injury in NLPs. Lastly, we constructed a protein-protein interaction network to show the interaction and connections of genes that are differentially expressed in NLPs and ULPs. This study has identified the genes that might regulate the proliferation and HC regeneration of Lgr5+ progenitors after neomycin injury, and investigations into the roles and mechanisms of these genes in the cochlea should be performed in the future to identify potential therapeutic targets for HC regeneration.

Effects of Semont maneuver on benign paroxysmal positional vertigo: a meta-analysis

Abstract Background: Benign paroxysmal positional vertigo (BPPV) is the most common type of peripheral vertigo. This study aimed to evaluate the effects of the Semont maneuver (SM) for BPPV treatment, compared with other methods. Methods: Studies were selected in relevant databases under pre-defined criteria up to June 2015. The Cochrane evaluation system was used to assess the quality of the studies. Effect size was indicated as a risk-ratio (RR) with corresponding 95% confidential interval (CI). Statistical analysis was conducted under a randomized- or fixed-effects model. Sub-group analysis was performed. Results: Ten studies were included in the meta-analysis. All of the studies presented a low attrition bias, but a high selection and reporting bias. SM had a much higher recovery rate (SM vs no treatment: RR = 2.60, 95% CI = 1.97–3.44, p < 0.01; SM vs sham: RR = 4.89, 95% CI = 3.01–7.94, p < 0.01), and lower recurrence rate than those from controls (SM vs no treatment: RR = 0.11, 95% CI = 0.04–0.31, p < 0.01). Overall, SM had similar outcomes with Epley maneuver (EM) and Brandt-Daroff exercise (BDE) in terms of recovery rate, recurrence rate, and side-effects. Conclusion: SM is as effective as EM and BDE for BPPV treatment.

Schwannoma of the Sinonasal Tract and the Pterygopalatine Fossa with or without Intracranial Extension.

Aims: Compared with those in other head and neck regions, schwannomas in the nasal cavity or paranasal sinuses are rare. The aim of this study was to present the experience of the authors in 11 schwannoma cases of the sinonasal tract and pterygopalatine fossa over a decade. Methods: A retrospective study from 2003 to 2014. Results: Three female and 8 male patients from 22 to 61 years of age (mean age 42 years) were admitted. The most common complaints were unilateral nasal congestion. A total of 10 of the patients received surgery, including 6 functional endoscopic sinus surgeries (FESS). The postoperative course was generally uneventful. Among the patients, 10 remained regionally asymptomatic, and there has been no clinical or radiological evidence of recurrence or residual tumor. Conclusion: Surgical treatment is effective for schwannomas of the sinonasal tract and the pterygopalatine fossa with a low recurrence rate. Conducting CT and MRI (particularly fluid-attenuated inversion recovery) before surgery is mandatory. FESS could become the primary treatment of choice.

Myosin light chain kinase regulates hearing in mice by influencing the F-actin cytoskeleton of outer hair cells and cochleae

Myosin light chain kinase (MLCK) phosphorylates myosin regulatory light chains to facilitate its interaction with actin filaments and produce contractile activity. The outer hair cells (OHCs) in the ear contain large amounts of actin and a variety myosins. The stereociliary and somatic motility of OHCs are closely related to hearing. It appears likely that MLCK may play an important role in acoustic trans-duction. In this study, we analyzed, both in vivo and in vitro, the OHCs of mice bearing a specific deletion of the MLCK gene and the OHCs of control mice. The phenotype was assessed by auditory function [acoustic brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs)], inner ear morphology and histology. MLCK-deficient mice aged 6-7 months showed impaired hearing, a 5- to 10-dB sound pressure level (SPL) increase in the ABR thresholds, when responding to clicks and tones of different frequencies (8 and 16 kHz) (P<0.05). The DPOAE amplitudes of 3-month-old MLCK-deficient mice decreased significantly (>10 dB SPL) at low frequencies (4, 5 and 6 kHz). The OHCs in the MLCK-deficient mice increased with abnormal stereocilia. The staining of F-actin and the phosphorylation of the regulatory light chain in MLCK-deficient OHCs was weak. Our results indicate that MLCK may regulate the structure and the motility of stereocilia through F-actin polymerization.

Loss of ARHGEF6 Causes Hair Cell Stereocilia Deficits and Hearing Loss in Mice

ARHGEF6 belongs to the family of guanine nucleotide exchange factors (GEFs) for Rho GTPases, and it specifically activates Rho GTPases CDC42 and RAC1. Arhgef6 is the X-linked intellectual disability gene also known as XLID46, and clinical features of patients carrying Arhgef6 mutations include intellectual disability and, in some cases, sensorineural hearing loss. Rho GTPases act as molecular switches in many cellular processes. Their activities are regulated by binding or hydrolysis of GTP, which is facilitated by GEFs and GTPase-activating proteins, respectively. RAC1 and CDC42 have been shown to play important roles in hair cell (HC) stereocilia development. However, the role of ARHGEF6 in inner ear development and hearing function has not yet been investigated. Here, we found that ARHGEF6 is expressed in mouse cochlear HCs, including the HC stereocilia. We established Arhgef6 knockdown mice using the clustered regularly interspaced short palindromic repeat-associated Cas9 nuclease (CRISPR-Cas9) genome editing technique. We showed that ARHGEF6 was indispensable for the maintenance of outer hair cell (OHC) stereocilia, and loss of ARHGEF6 in mice caused HC stereocilia deficits that eventually led to progressive HC loss and hearing loss. However, the loss of ARHGEF6 did not affect the synapse density and did not affect the mechanoelectrical transduction currents in OHCs at postnatal day 3. At the molecular level, the levels of active CDC42 and RAC1 were dramatically decreased in the Arhgef6 knockdown mice, suggesting that ARHGEF6 regulates stereocilia maintenance through RAC1/CDC42.

A Cross-Sectional Study on the Hearing Threshold Levels Among People in Qinling, Qinghai, and Nanjing, China

Purpose This study aimed to investigate the hearing threshold among different age groups, genders, and geographic areas in China to provide some insight into the appropriate clinical interventions for hearing loss. Method Using a systematic random sampling technique, 562 participants from Qinling, Qinghai, and Nanjing were included. Participants in the same area were divided into 3 groups according to their age. Pure-tone audiometric thresholds were measured at octave and interoctave frequencies of 0.125-16 kHz for each subject. Results There were significant differences in auditory thresholds at nearly all frequencies among young, middle-aged, and elderly people, and hearing thresholds increased with increasing age. People generally had the best hearing ability in Nanjing, better hearing ability in Qinghai, and the worst hearing ability in Qinling. Significant differences in hearing thresholds were found between males and females at several frequencies in Qinling. Conclusion People living in the rural area of Qinling in China had higher hearing threshold levels, particularly males, and hearing thresholds increased with age.

HPV16 E6 Promotes Breast Cancer Proliferation via Upregulation of COX-2 Expression

Background. Breast cancer remains the leading cause of cancer-related mortality worldwide. It has been indicated that human papillomaviruses 16 (HPV16) might participate in the pathogenesis and development of breast cancer. However, the detected rate of HPV16 varies with region. We will investigate HPV16 E6 expression in North China and explore the effects and mechanism of HPV16 E6 on breast cancer proliferation in this study. Methods. The expressions of HPV16 E6 and COX-2 in paraffin-embedded tissues of the invasive ductal breast cancer were detected by qPCR and IHC. The effects of HPV16 E6 on breast cancer proliferation were determined by function studies. The mechanism of HPV16 E6 in promoting breast cancer proliferation was explored by Western blot and Dual-Luciferase Reporter Assay. Results. HPV16 E6 was positive in 28% invasive ductal breast carcinoma in North China; HPV16 E6 promoted breast cancer proliferation. Inhibition of COX-2 by siCOX-2 or Celecoxib attenuated the proliferation of breast cancer cells with HPV16 E6 expression; and the upregulation of COX-2 could be suppressed by the inhibition of NF-κB activity. Conclusion. HPV16 E6 promotes breast cancer proliferation by activation of NF-κB signaling pathway and increase of COX-2 expression. COX-2 will be a potential target for HPV16 E6-associated breast cancer.