Aldh inhibitor restores auditory function in a mouse model of human deafness

Genetic hearing loss is a common health problem with no effective therapy currently available. DFNA15, caused by mutations of the transcription factor POU4F3, is one of the most common forms of autosomal dominant non-syndromic deafness. In this study, we established a novel mouse model of the human DFNA15 deafness, with a Pou4f3 gene mutation (Pou4f3Δ) identical to that found in a familial case of DFNA15. The Pou4f3(Δ/+) mice suffered progressive deafness in a similar manner to the DFNA15 patients. Hair cells in the Pou4f3(Δ/+) cochlea displayed significant stereociliary and mitochondrial pathologies, with apparent loss of outer hair cells. Progression of hearing and outer hair cell loss of the Pou4f3(Δ/+) mice was significantly modified by other genetic and environmental factors. Using Pou4f3(-/+) heterozygous knockout mice, we also showed that DFNA15 is likely caused by haploinsufficiency of the Pou4f3 gene. Importantly, inhibition of retinoic acid signaling by the aldehyde dehydrogenase (Aldh) and retinoic acid receptor inhibitors promoted Pou4f3 expression in the cochlear tissue and suppressed the progression of hearing loss in the mutant mice. These data demonstrate Pou4f3 haploinsufficiency as the main underlying cause of human DFNA15 deafness and highlight the therapeutic potential of Aldh inhibitors for treatment of progressive hearing loss.

More than 50% of deafness cases are due to genetic defects with no treatment available. DFNA15, caused by mutations of the transcription factor POU4F3, is one of the most common types of autosomal dominant non-syndromic deafness. Here, we established a novel mouse model with the exact Pou4f3 mutation identified in human patients. The mutant mouse display similar auditory pathophysiology as human patients and exhibit multiple hair cell abnormalities. The onset and severity of hearing loss in the mouse model is highly modifiable to environmental factors, such as aging, noise exposure or genetic backgrounds. Using a new knockout mouse model, we found Pou4f3 haploinsufficiency as the underlying mechanism of human DFNA15. Importantly, we identified Aldh inhibitor as a potent small molecule for upregulation of Pou4f3 and treatment of hearing loss in the mutant mouse. The identification of Aldh inhibitor for treatment of DFNA15 deafness represents a major advance in the unmet medical need for this common form of progressive hearing loss.

[The possible mechanisms of simvastatin on apoptosis of lung adenocarcinoma cells]

Objective: To explore the possible mechanisms of simvastatin-induced apoptosis in lung adenocarcinoma cells. Methods: The experiment was divided into control group (vehicle treated A549 cells), different concentrations (10, 20, 40, 80 mg/L) simvastatin group (simvastatin treated with different concentrations of A549 cells), aspartate specific proteinase (caspase) inhibitor (Z-VAD-FMK) group (50 μmol/L Z-VAD-FMK treated A549 cells), 40 mg/L simvastatin combined with Z-VAD-FMK group (40 mg/L simvastatin combined with 50 μmol/L Z-VAD-FMK co-treated A549 cells), interleukin-6 (IL-6) group (IL-6 acts on A549 cells) and different concentrations (10, 20, 40 mg/L) simvastatin combined with IL-6 group (simvastatin combined with IL-6 act on A549 cells). Cell counting kit-8 (CCK8) method was used to detect the effect on survival rate of lung adenocarcinoma A549 cells; Flow cytometry was used to detect the effect of simvastatin on A549 cell cycle; Mitochondrial membrane potential-1 (JC-1) fluorescent probe was wsed to detect the effect of simvastatin on mitochondrial membrane potential (MMP); Flow-type phosphatidl serine protein antibody Annexin V/propidium iodide (Annexin V-FITC/PI) double staining method was used to detect the effect of simvastatin on A549 cell apoptosis; CCK8 method was used to detect the effect of Z-VAD-FMK on the survival rate of A549 cells; TdT-mediated 2'-deoxyuridine 5'-triphosphate (dUTP) nick end labeling (TUNEL) method was used to detect the effect of Z-VAD-FMK on simvastatin-induced apoptosis in A549 cells; Western blot method was used to detect the effect of simvastatin on the expression levels of Janus kinase 2 and activation of signal transducers and activators of transcription 3 (JAK2/STAT3) pathway-related proteins phosphorylated JAK2 (p-JAK2), JAK2, phosphorylated STAT3 (p-STAT3), and STAT3 before and after the activator IL-6 of JAK2/STAT3 pathway acted on A549 cells. Results: The survival rates of A549 cells in the 20-80 mg/L simvastatin-treated groups were significantly lower than that in the control group (all P<0.05), and gradually decreased with the increase of the concentration of the simvastatin and the extension of the action time. The cells in the G(0)/G(1) phase of the simvastatin group were significantly higher than those in the control group, and the cells in the G(2)/M phase were significantly lower than those in the control group (all P<0.01). The MMP of the treatment group with different concentrations of simvastatin was significantly lower than that of the control group (all P<0.05). The apoptosis rate of the 20 mg/L and 40 mg/L simvastatin-treated group was significantly higher than that of the control group (both P<0.01). The cell survival rate of the 40 mg/L simvastatin group and the 40 mg/L simvastatin combined with Z-VAD-FMK group were (52.2±2.7)% and (57.5±3.8)%, respectively, were lower than that of the control group (100.0±2.7)% (both P<0.01). But the difference between 40 mg/L simvastatin group and the simvastatin combined with Z-VAD-FMK group was not statistically significant (P>0.05). The cell numbers with positive fluorescent staining in the 40 mg/L simvastatin group were significantly more than those in the control group, but the cell numbers with positive fluorescent staining in the 40 mg/L simvastatin combined with Z-VAD-FMK group had no statistical significance compared with the simvastatin group (P>0.05). The specific value of p-JAK2/JAK2 and p-STAT3/STAT3 protein relative expressions in the simvastatin-treated group (20, 40 mg/L) were significantly lower than that in the control group, respectively (both P<0.05). The specific value of p-JAK2/JAK2 and p-STAT3/STAT3 protein relative expressions in IL-6 group were significantly higher than those in control group (both P<0.05), the specific value of p-JAK2/JAK2 and p-STAT3/STAT3 protein relative expressions in simvastatin (20, 40 mg/L) combined with IL-6 groups were lower than those in IL-6 group (all P<0.05), respectively. Conclusion: Simvastatin can induce the apoptosis of A549 cells through a non-caspase-dependent mitochondrial apoptosis pathway, which may be achieved by inhibiting the JAK2/STAT3 pathway.

[Identification of a novel mutation of SLC26A4 gene with enlarged vestibular aqueduct syndrome]

Objective:To explore the mutation spectrum of SLC26A4 in Chinese patients with enlarged vestibular aqueduct syndrome.Method:Genomic DNA samples were extracted from peripheral blood of the cochlear implant recipients associated with enlarged vestibular aqueduct syndrome. The SLC26A4 mutations were analyzed by direct sequencing.Result:A novel missense mutation(347G>A) of SLC26A4 gene was found in a male patient,which led to a substitution of codon 116 from glycine to asparagic acid. This mutation was not observed among 60 normal controls.Conclusion:The 347G>A of SLC26A4 gene was a novel pathologic mutation,contributing to the mutation spectrum of SLC26A4 of enlarged vestibular aqueduct syndrome.

Inhibition of Myo6 gene expression by co‑expression of a mutant of transcription factor POU4F3 (BRN‑3C) in hair cells

An eight‑base pair (bp) deletion in the Pou4f3 gene in hair cells is associated with DFNA15, a hereditary form of hearing loss. To explore the pathological mechanisms underlying the development of DFNA15, the effect of the mutation in Pou4f3 on the activity of the myosin VI (Myo6) promoter, was investigated. The upstream regulatory sequence of Myo6 (2625 bp), consisting of an 1899 bp upstream sequence and a 727 bp intron 1 sequence, was amplified using polymerase chain reaction and subcloned into the pGL3‑Basic vector expressing firefly luciferase. For verification of inserted fragments, plasmids were subjected to restriction analysis and then sequenced. HEK293T human embryonic kidney cells were transiently transfected with renilla luciferase‑thymidine kinase vectors expressing Renilla luciferase and the Myo6 promoter‑driven firefly luciferase expressing vectors along with pIRES2‑enhanced green fluorescent protein (EGFP)‑Pou4f3 (expressing wild‑type Pou4f3) or pIRES2‑EGFP‑Pou4f3 (expressing the truncation mutant of Pou4f3). The relative luciferase activities were measured to determine the activity of the Myo6 promoter. The Myo6 promoter activity was not affected by co‑expression of wild‑type Pou4f3, as indicated by the comparable relative luciferase activities in the presence of the pIRES2‑EGFP‑Pou4f3 and the empty control vectors. However, co‑expression of mutated Pou4f3 significantly inhibited the activity of the Myo6 promoter to almost half of that of the control (P<0.001). The data suggests that mutated Pou4f3 has a negative role in the promoter activity of Myo6, and by extension, the expression of myosin VI, and this may be an underlying mechanism of DFNA15 hearing loss.

[Study on conditional myosin light chain kinase gene knockout mice resulting in hearing loss]

OBJECTIVE

To investigate the function of myosin light chain kinase (MLCK) in hearing in mouse by generating inner hair cell-specific Mlck knockout mice and analyze the effect on their hearing.

METHODS

Cross Mlck floxed mice with IHC-Cre mice, the genotype and knockout efficiency were confirmed by PCR. We used auditory brain stem response (ABR) to evaluate mice hearing function at different frequencies.

RESULTS

Mlck knockout mice were selected by mice tail DNA genotyping and confirmed the deletion of the target gene by isolated inner hair cell DNA genotyping. Mlck-deficient mice showed impaired hearing with a rise in ABR threshold response to click and three different pure tones (8 kHz, 16 kHz, 32 kHz), and the rise was over 20 dB at high-frequency(32 kHz). Further analyses of waveforms showed that wave-I amplitudes on 60 dB SPL, 50 dB SPL and 40 dBSPL in response to tone (16 kHz) were less than control group(P < 0.05) on average, but the ratio of wave I/II and I/III were not difference (P > 0.05).

CONCLUSIONS

Mlck is successfully deleted in inner hair cell-specific Mlck knockout mice. Mlck knockout mice display a significantly higher threshold in response to click and tones, especially in high-frequencies.

[Anaplastic carcinoma of the thyroid: an analysis of 33 cases]

Thirty-three patients with anaplastic carcinoma of the thyroid were treated during the past 30 years with 27 cases of simple anaplastic carcinoma and the other 6 found also with some differentiated carcinoma component. survival rate of 3.5 and 10 years were 35.5%, 36.7% and 29.6%, respectively. The survival rate of patients younger than 45 years were higher than older, and of those with tumor size less than 4cm in diameter were better than that with larger size. Patients received radical surgery plus adjuvant therapy had better survival rate, and patients with differentiated carcinoma component had better survival rate. This study suggested that surgical treatment plus adjuvant therapy is the treatment of choice in anaplastic carcinoma of the thyroid, and the extent of the operation must be dependent on the size of primary tumor.

A novel enzymatic decarboxylation of oxalic acid by the lignin peroxidase system of white-rot fungus Phanerochaete chrysosporium

Oxidation of veratryl alcohol by lignin peroxidase (LiP) was potently inhibited by oxalic acid. The inhibition analysis with Lineweaver-Burk plots clearly showed that the type of inhibition is non-competitive. The enzymatic oxidation of veratryl alcohol in the presence of 14C-oxalic acid yielded radioactive carbon dioxide. The results indicate that the apparent inhibition of LiP is caused by reduction of the veratryl alcohol cation radical intermediate back to the substrate level by oxalate, which is concomitantly oxidized to carbon dioxide.

[Salvage surgery for cervical residual and recurrent lesions of nasopharyngeal carcinoma after radiotherapy]

Recently, in spite of the great progress made in the radiotherapy for NPC, there remains 10 approximately 20% of patients who would die of their cervical lesions, either residual or recurrent after irradiation. It is well known that the skin of the neck can not tolerate too high a dose of radiation and the cervical metastatic lymph nodes of NPC may be less sensitive to radiation than the primary. From April 1977 to March 1987, 79 NPC patients with persistent cervical lymph node metastasis after irradiation were treated by salvage surgery (31 residual and 48 recurrent cancers). Most of the lesions were located in the upper neck (64 cases) and a few along the margin of previous radiation field, such as submaxillary or posterior cervical triangle. Of the 69 patients treated by salvage neck dissection, 38 were confirmed pathologically to have soft tissues involvement, such as sternocleidomastoid, digastric, splenius, and levator scapular muscles, and 2 had hypoglossus nerve and carotid sheath involvement. The authors emphasized that all the involved tissues, such as skin, muscle, nerve or jugular vein should be resected completely. If the neck defect could not be closed primarily, the pectoral major myocutaneous flap (7 cases) or lateral trapezius myocutaneous flap (3 cases) were used for repair. There were no postoperative complications. 32 patients were followed over 3 years with a 3-year survival rate of 34% (11/32). 43 were followed less than 3 years. 31 were alive and 12 were dead.(ABSTRACT TRUNCATED AT 250 WORDS)

The infrahyoid myocutaneous flap for reconstruction after resection of head and neck cancer

From May 1979 to August 1984, 112 infrahyoid myocutaneous flaps (IHMCFs) were used for reconstruction of the tongue after resection of lingual carcinoma (67 flaps in 63 consecutive cases) and for repair of defects after resection of carcinomas of buccal mucosa (23 cases), floor of mouth (8 cases), parotid gland (7 cases), and other malignancies (7 cases). Ten IHMCFs were extended to Ludwig's angle for repairing the open defect of the cheek or combined defect in the buccal mucosa and hard palate. The donor sites of 76 IHMCFs could be sutured primarily. The flap was successful in 90% of the cases (101 of 112 cases). Postoperatively, 94% of the cases (60 of 64 cases) of reconstructed tongue had good deglutition and 78% of the cases (50 of 64 cases) gave satisfactory enunciation. IHMCF is a new, versatile, reliable, and convenient flap suitable for repairing the defects in and around the oral cavity, particularly in the tongue, even in aged and weak patients.