We report a novel mutation (erlong, erl) of the cadherin 23 (Cdh23) gene in a mouse model for DFNB12 characterized by progressive hearing loss beginning from post-natal day 27 (P27). Genetic and sequencing analysis revealed a 208T>C transition causing an amino acid substitution (70S-P). Caspase expression was up-regulated in mutant inner ears. Hearing was preserved (up to 35-dB improvement) in pan-caspase inhibitor Z-VAD-FMK-treated mutants compared to untreated mutants (P < 0.05). Outer hair cell (OHC) loss in the cochleae of Z-VAD-FMK-treated mutants was significantly reduced compared to those of untreated mice. Thus, the erl mutation can lead to hearing loss through apoptosis. This is the first genetic mouse model of hearing loss shown to respond to otoprotective drug therapy. The short interval from initial hearing loss to deafness (P27-P90) makes this model ideal for screening and validating otoprotective drugs.

Streptococcus pneumoniae is the most common pathogen associated with otitis media. To examine the role of Toll-like receptor 2 (TLR2) in host defense against Streptococcus pneumoniae infection in the middle ear, wild-type (WT; C57BL/6) and TLR2-deficient (TLR2 ؊/؊ ) mice were inoculated with Streptococcus pneumoniae (1 ؋ 10 6 CFU) through the tympanic membrane. Nineteen of 37 TLR2 ؊/؊ mice showed bacteremia and died within 3 days after the challenge, compared to only 4 of 32 WT mice that died. Of those that survived, more severe hearing loss in the TLR2 ؊/؊ mice than in the WT mice was indicated by an elevation in auditory-evoked brain stem response thresholds at 3 or 7 days postinoculation. The histological pathology was characterized by effusion and tissue damage in the middle ear, and in the TLR2 ؊/؊ mice, the outcome of infection became more severe at 7 days. At both 3 and 7 days postchallenge, the TLR2 ؊/؊ mice had higher blood bacterial titers than the WT mice (P < 0.05), and typical bacteria were identified in the effusion from both ears of both mouse groups by acridine orange staining. Moreover, by 3 days postchallenge, the mRNA accumulation levels of NF-B, tumor necrosis factor alpha, interleukin 1␤, MIP1␣, Muc5ac, and Muc5b were significantly lower in the ears of TLR2 ؊/؊ mice than in WT mice. In summary, TLR2 ؊/؊ mice may produce relatively low levels of proinflammatory cytokines following pneumococcal challenge, thus hindering the clearance of bacteria from the middle ear and leading to sepsis and a high mortality rate. This study provides evidence that TLR2 is important in the molecular pathogenesis and host response to otitis media.Streptococcus pneumoniae, a gram-positive bacterium, is one of the two most common pathogens involved in acute middle ear infection, which frequently leads to acquired hearing loss and communication disorders in children (20). The first line of host defense against bacterial infection by the innate immune system is essentially initiated by Toll-like receptors (TLRs), family-pattern-recognition receptors that detect and respond to microbial ligands (3). TLR2 mediates host responses to gram-positive bacterial cell wall components such as peptidoglycan (PGN), lipoteichoic acids (LTA), and lipoproteins (1, 37). TLR2 may function as a regulator of inflammation, and abnormal immune inflammatory responses develop in the absence of TLR2. In humans, one mutation in the TLR2 gene results in an Arg753Gln polymorphism that predisposes individuals to life-threatening bacterial infections (22). TLR2-deficient (TLR2 Ϫ/Ϫ ) mice succumb to Mycobacterium tuberculosis infection (6) and are highly susceptible to Staphylococcus aureus infection (32). TLR2 Ϫ/Ϫ mice show delayed pneumococcal phagocytosis and impaired oxidative killing by granulocytes (17). Studies have also demonstrated that TLR2 participates in the mediation of the immune response in experimental pneumococcal meningitis (16,18) and that mice with a targeted disruption of the TLR2 gene are more susceptible to meningitis-induce...

Glioma is among the ten most common causes of cancer-related death and has no effective treatment for it, so we are trying to find a new target for anticancer treatment. This study investigates the different expression of SRPK1 as a novel protein in glioma, which can influence tumor cells biological characteristics in normoxic and hypoxic environment. The expression levels of SRPK1 protein in glioma cell lines transfected with siSRPK1 or not were examined using immunofluorescence, RT-PCR and Western blot analysis, respectively. The impact of SRPK1 on the biological characteristics of U251 cells was further studied using methylthiazol tetrazolium assays, flow cytometry, and Transwell invasion chamber assays. The results showed that knockdown of SRPK1 inhibited tumor cells growth, invasion and migration in normoxic condition, but portion of the effect could be reversed in hypoxia. SRPK1 expression was induced in glioma cells by DDP treated, but not TMZ, in both normoxia and hypoxia conditions. We propose SRPK1 as a new molecular player contributing to the early treatment of glioma.

Gliomas, the most common primary brain tumors, have low survival rates and poorly defined molecular mechanisms to target for treatment. Serine/arginine SR protein kinases 1 (SRPK1) can highly and specifically phosphorylate the SR protein found in many tumors, which can influence cell proliferation and angiogenesis. However, the roles and regulatory mechanisms of SRPK1 in gliomas are not understood. The aim of this study was to determine the functions and regulation of SRPK1 in gliomas. We found that SRPK1 inhibition induces early apoptosis and significantly inhibits xenograft tumor growth. Our results indicate that SRPK1 affects Akt and eIF4E phosphorylation, Bax and Bcl-2 activation, and HIF-1 and VEGF production in glioma cells. Moreover, transfection of SRPK1 siRNA strongly reduced cell invasion and migration by regulating the expression of MMP2 and MMP9 and significantly decreased the volume of tumors and angiogenesis. We show here that a strong link exists among SRPK1, Akt, eIF4E, HIF-1, and VEGF activity that is functionally involved in apoptosis, metastasis, and angiogenesis of gliomas under normoxic conditions. Thus, SRPK1 may be a potential anticancer target to inhibit glioma progression.

Otitis media is a middle ear disease common in children under three years old. Otitis media can occur in normal individuals with no other symptoms or syndromes, but it is often seen in individuals clinically diagnosed with genetic diseases such as CHARGE syndrome, a complex genetic disease caused by mutation in the Chd7 gene and characterized by multiple birth defects. Although otitis media is common in human CHARGE syndrome patients, it has not been reported in mouse models of CHARGE syndrome. In this study, we report a mouse model with a spontaneous deletion mutation in the Chd7 gene and with chronic otitis media of early onset age accompanied by hearing loss. These mice also exhibit morphological alteration in the Eustachian tubes, dysregulation of epithelial proliferation, and decreased density of middle ear cilia. Gene expression profiling revealed up-regulation of Muc5ac, Muc5b and Tgf-β1 transcripts, the products of which are involved in mucin production and TGF pathway regulation. This is the first mouse model of CHARGE syndrome reported to show otitis media with effusion and it will be valuable for studying the etiology of otitis media and other symptoms in CHARGE syndrome.

Fascin2 (FSCN2) is an actin cross-linking protein that is mainly localized in retinas and in the stereocilia of hair cells. Earlier studies showed that a deletion mutation in human FASCIN2 (FSCN2) gene could cause autosomal dominant retinitis pigmentosa. Recent studies have indicated that a missense mutation in mouse Fscn2 gene (R109H) can contribute to the early onset of hearing loss in DBA/2J mice. To explore the function of the gene, Fscn2 was knocked out using TALEN (transcription activator-like effector nucleases) on the C57BL/6J background. Four mouse strains with deletions of 1, 4, 5, and 41 nucleotides in the target region of Fscn2 were developed. F1 heterozygous (Fscn2+/−) mice carrying the same deletion of 41 nucleotides were mated to generate the Fscn2−/− mice. As a result, the Fscn2−/− mice showed progressive hearing loss, as measured in the elevation of auditory brainstem-response thresholds. The hearing impairment began at age 3 weeks at high-stimulus frequencies and became most severe at age 24 weeks. Moreover, degeneration of hair cells and loss of stereocilia were remarkable in Fscn2−/− mice, as revealed by F-actin staining and scanning electron microscopy. Furthermore, compared to the controls, the Fscn2−/− mice displayed significantly lower electroretinogram amplitudes and thinner retinas at 8, 16, and 24 weeks. These results demonstrate that, in C57BL/6Jmice, Fscn2 is essential for maintaining ear and eye function and that a null mutation of Fscn2 leads to progressive hearing loss and retinal degeneration.

Summary The Ts65Dn mouse shares many phenotypic characteristics of human Down syndrome. Here, we report that otitis media, characterized by effusion in the middle ear and hearing loss, was prevalent in Ts65Dn mice. Of the 53 Ts65Dn mice tested, 81.1% had high auditory-evoked brainstem response (ABR) thresholds for at least one of the stimulus frequencies (click, 8 kHz, 16 kHz and 32 kHz), in at least one ear. The ABR thresholds were variable and showed no tendency toward increase with age, from 2 to 7 months of age. Observation of pathology in mice, aged 3–4 months, revealed middle ear effusion in 11 of 15 Ts65Dn mice examined, but only in two of 11 wild-type mice. The effusion in each mouse varied substantially in volume and inflammatory cell content. The middle ear mucosae were generally thickened and goblet cells were distributed with higher density in the epithelium of the middle ear cavity of Ts65Dn mice as compared with those of wild-type controls. Bacteria of pathogenic importance to humans also were identified in the Ts65Dn mice. This is the first report of otitis media in the Ts65Dn mouse as a model characteristic of human Down syndrome.

Usher syndrome (USH) is the most common form of deaf-blindness in humans. Molecular characterization revealed that the USH gene products form a macromolecular protein network in hair cells of the inner ear and in photoreceptor cells of the retina via binding to PDZ domains in the scaffold protein harmonin encoded by the Ush1c gene in mice and humans. Although several mouse mutants for the Ush1c gene have been described, we generated a targeted null mutation Ush1c mouse model in which the first four exons of the Ush1c gene were replaced with a reporter gene. Here, we assessed the expression pattern of the reporter gene under control of Ush1c regulatory elements and characterized the phenotype of mice defective for Ush1c. These Ush1 knockout mice are deaf but do not recapitulate vision defects before 10 months of age. Our data show LacZ expression in multiple layers of the retina but in neither outer nor inner segments of the photoreceptor layers in mice bearing the knockout construct at 1-5 months of age. The fact that Ush1c expression is much higher in the ear than in the eye suggests a different role for Ush1c in ear function than in the eye and may explain why Ush1c mutant mice do not recapitulate vision defects. This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. KeywordsAuthors' contributions: CT performed the immunoassays. XZL contributed to initial research design. FC and CT performed the molecular studies including real-time PCR and sequence analyses. HY performed ABR tests, the immunoassays, contributed to generation of backcross and Ush1c −/− mice. CT and CLG contributed the lacZ reporter gene expression and hair bundle assay, CLG performed the SEM assay. BY and CL performed genotyping, DY performed literature research. QYZ conceived and designed the study, supervised all the experimental data analyses and the manuscript preparation. All authors read and approved the final manuscript.NIH Public Access