MicroRNA-222 alleviates radiation-induced apoptosis by targeting BCL2L11 in cochlea hair cells.

Radiation-induced hair cell injury is detrimental for human health but the underlying mechanism is not clear. MicroRNAs (miRNAs) have critical roles in various types of cellular biological processes. The present study investigated the role of miR-222 in the regulation of ionizing radiation (IR)-induced cell injury in auditory cells and its underlying mechanism. Real-time PCR was performed to identify the expression profile of miR-222 in the cochlea hair cell line HEI-OC1 after IR exposure. miRNA mimics or inhibitor-mediated up- or down-regulation of indicated miRNA was applied to characterize the biological effects of miR-222 using MTT, apoptosis and DNA damage assay. Bioinformatics analyses and luciferase reporter assays were applied to identify an miRNA target gene. Our study confirmed that IR treatment significantly suppressed miR-222 levels in a dose-dependent manner. Up-regulation of miR-222 enhances cell viability and alleviated IR-induced apoptosis and DNA damage in HEI-OC1 cells. In addition, BCL-2-like protein 11 (BCL2L11) was validated as a direct target of miR-222. Overexpression of BCL2L11 abolished the protective effects of miR-222 in IR-treated HEI-OC1 cells. Moreover, miR-222 alleviated IR-induced apoptosis and DNA damage by directly targeting BCL2L11. The present study demonstrates that miR-222 exhibits protective effects against irradiation-induced cell injury by directly targeting BCL2L11 in cochlear cells.

Increased expression of MUC5AC and MUC5B promoting bacterial biofilm formation in chronic rhinosinusitis patients.

OBJECTIVE: Binding of bacteria to mucin and then colonizing is the first step of bacterial biofilm (BBF) formation in chronic rhinosinusitis (CRS) patients. Yet, information is sparse on how mucins effects on BBF formation. In this study, we aimed to investigate the relationship between mucin expression and the formation of BBF in CRS patients. METHODS: Sinus mucosa were harvested from 24 patients undergoing endoscopic surgery for CRS. The positive of BBF formation were detected by scanning electronic microscopy (SEM) and the expression of MUC1, MUC2, MUC5AC, and MUC5B were determined by immunohistochemistry (IHC). The difference expression of mucins were analyzed between the BBF positive and negative cohorts in CRS patients. RESULTS: MUC5AC and MUC5B are two major mucins in CRS mucosa with the former mainly restricted to the goblet cells of epithelium and the latter mainly restricted to the submucosal glands. Expression of MUC5AC and MUC5B in the sinus mucosa of BBF(+) CRS group was significantly higher than those in BBF(-) CRS group (p<0.05). For MUC1 and MUC2, no significant difference was found between the two groups (p>0.05). CONCLUSION: Our study indicated that increased expression of MUC5AC and MUC5B may play an important role in the pathogenesis of BBF formation.

Bacterial biofilms in chronic rhinosinusitis and their relationship with inflammation severity.

AIMS: To identify the presence of bacterial biofilms on mucosal specimens from chronic rhinosinusitis (CRS) patients, and evaluate their relationship with severity of CRS. METHODS: A prospective study of biofilms presence on 24 CRS patients compared with 12 controls was designed. The presence of biofilms was determined by scanning electron microscopy (SEM), and associations with the preoperative Lund-MacKay CT scores, Johansson endoscopic scores, and the history of ESS were assessed. RESULTS: Biofilms were found in 13/24 CRS patients (54.2%) but in only 1/12 controls (8.3%; P<0.01). CRS patients with and without biofilms had similar preoperative Lund-MacKay CT and Johansson endoscopic scores (P>0.05). Patients with revision ESS showed a tendency of higher biofilms incidence (5/7, 71.4%) than those undergoing their first procedure (8/17, 47.1%), but did not reach a significant difference (P>0.05). CONCLUSIONS: The higher incidence of biofilms in CRS patients suggests a role in the pathogenesis of CRS, but no correlation with severity of CRS.

[Relationship between bacterial biofilms and chronic rhinosinusitis by scanning electron microscopic study].

OBJECTIVE: To determine the presence and the morphological features of bacterial biofilms in surgical specimens of patients with chronic rhinosinusitis (CRS) compared with control patients without CRS by scanning electron microscopy (SEM), and to evaluate the role of biofilm on the pathogenesis of CRS. METHODS: Fifteen patients with CRS undergoing endoscopic sinus surgery and 11 control patients with fracture of nasal bone were enrolled in this study. Clinical information was recorded from each patient. All patients underwent a thorough otolaryngological examination, preoperative paranasal sinus computerized tomography (CT) scanning which were evaluated according to the Lund-Mckay CT scoring system. All the samples including uncinate process, ethmoid mucosa from CRS group and uncinate process, ethmoid bulla from control group were prepared using standard methods for SEM. The presence of bacterial biofilms on the samples of two groups was observed by SEM. Statistical analysis was performed using SPSS 13.0. Continuous data was analyzed by Student t test and dichotomous data was analyzed by chi² or Fisher exact test. P was considered to be significant at a level of 0.05. RESULTS: Nine (60.0%) of the 15 patients were found to have evidence of biofilms. In control group, only 1 (9.1%) of 11 patients had biofilm. The difference was statistical significant (chi² = 6.949, P < 0.01). All controls except one had healthy appearing cilia and goblet cells without biofilms. All the 16 CRS patients showed aberrant findings of the mucosal surface with variation in degrees of severity from disarrayed cilia to complete absence of cilia and goblet cells. Among them the typical morphologic feature such as water channels, 3-D structure, and matrix-embedding spherical or elliptical bodies were noted in 9 cases. Five samples including one case from control showed cilia aggregation. The preoperative CT scores of the CRS patients with biofilms (n = 9) were significantly higher than those without biofilms (n = 6, t = 2.14, P < 0.05). CONCLUSIONS: The typical morphologic feature of BF such as water channels, 3-D structure, and matrix-embedding spherical or elliptical bodies were noted in sinus mucosa of patients with CRS by the SEM. The positive rate of bacterial biofilms in CRS group was significantly higher compared to control group, which indicated bacterial biofilms might play an important role in the pathogenesis of CRS. Besides the typical bacterial biofilm features, cilia aggregation was found in five cases of CRS patients. We consider cilia aggregation can be regarded as one morphologic feature of bacterial biofilm in nasal mucosa, which needs further study. The presence of bacterial biofilms in CRS patients is associated with paranasal CT scores, which indicates that bacterial biofilm is correlated with the severity of CRS.