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1.
Dev Biol ; 485: 1-8, 2022 05.
Article in English | MEDLINE | ID: mdl-35196518

ABSTRACT

Comparing the developmental mechanisms of segmentation among insects with different modes of embryogenesis provides insights on how the function of segmentation genes evolved. Functional analysis of eve by genetic mutants shows that the Drosophila pair-rule gene, even-skipped (eve), contributes to initial segmental patterning. However, eve orthologs tends to have diverse functions in other insects. To compare the evolutionary functional divergence of this gene, we evaluated eve function in a phylogenetically basal insect, the cricket Gryllus bimaculatus. To investigate the phenotypic effects of eve gene knock-out, we generated CRISPR/Cas9 system-mediated mutant strains of the cricket. CRISPR/Cas9 mutagenesis of multiple independent sites in the eve coding region revealed that eve null mutant embryos were defective in forming the gnathal, thoracic, and abdominal segments, consequently shortening the anterior-posterior axis. In contrast, the structures of the anterior and posterior ends (e.g., antenna, labrum, and cercus) formed normally. Hox gene expression in the gnathal, thoracic, and abdominal segments was detected in the mutant embryos. Overall, this study showed that Gryllus eve plays an important role in embryonic elongation and the formation of segmental boundaries in the gnathal to abdominal region of crickets. In the light of studies on other species, the eve function shown in Gryllus might be ancestral in insects.


Subject(s)
Drosophila Proteins , Gryllidae , Amino Acid Sequence , Animals , Body Patterning/genetics , Drosophila/genetics , Drosophila Proteins/metabolism , Gene Expression Regulation, Developmental/genetics , Gryllidae/genetics , Gryllidae/metabolism , Homeodomain Proteins/genetics , Homeodomain Proteins/metabolism , Insecta/genetics , Insecta/metabolism , RNA Interference , Transcription Factors/metabolism
2.
Int J Nanomedicine ; 13: 2365-2376, 2018.
Article in English | MEDLINE | ID: mdl-29713167

ABSTRACT

INTRODUCTION: The 3-dimensional scaffold plays a key role in volume and quality of repair tissue in periodontal tissue engineering therapy. We fabricated a novel 3D collagen scaffold containing carbon-based 2-dimensional layered material, named graphene oxide (GO). The aim of this study was to characterize and assess GO scaffold for periodontal tissue healing of class II furcation defects in dog. MATERIALS AND METHODS: GO scaffolds were prepared by coating the surface of a 3D collagen sponge scaffold with GO dispersion. Scaffolds were characterized using cytotoxicity and tissue reactivity tests. In addition, GO scaffold was implanted into dog class II furcation defects and periodontal healing was investigated at 4 weeks postsurgery. RESULTS: GO scaffold exhibited low cytotoxicity and enhanced cellular ingrowth behavior and rat bone forming ability. In addition, GO scaffold stimulated healing of dog class II furcation defects. Periodontal attachment formation, including alveolar bone, periodontal ligament-like tissue, and cementum-like tissue, was significantly increased by GO scaffold implantation, compared with untreated scaffold. CONCLUSION: The results suggest that GO scaffold is biocompatible and possesses excellent bone and periodontal tissue formation ability. Therefore, GO scaffold would be beneficial for periodontal tissue engineering therapy.


Subject(s)
Bone Regeneration/physiology , Furcation Defects/therapy , Graphite , Tissue Scaffolds , Wound Healing/physiology , Animals , Collagen/chemistry , Collagen/metabolism , Dental Cementum/physiology , Dogs , Female , Graphite/chemistry , Graphite/pharmacology , Male , Periodontal Ligament/physiology , Periodontal Ligament/physiopathology , Rats, Wistar , Tissue Engineering/methods
3.
Dent Mater J ; 36(5): 573-583, 2017 Sep 26.
Article in English | MEDLINE | ID: mdl-28450672

ABSTRACT

Three-dimensional collagen scaffolds coated with beta-tricalcium phosphate (ß-TCP) nanoparticles reportedly exhibit good bioactivity and biodegradability. Dose effects of ß-TCP nanoparticles on biocompatibility and bone forming ability were then examined. Collagen scaffold was applied with 1, 5, 10, and 25 wt% ß-TCP nanoparticle dispersion and designated TCP1, TCP5, TCP10, and TCP25, respectively. Compressive strength, calcium ion release and enzyme resistance of scaffolds with ß-TCP nanoparticles applied increased with ß-TCP dose. TCP5 showed excellent cell-ingrowth behavior in rat subcutaneous tissue. When TCP10 was applied, osteoblastic cell proliferation and rat cranial bone augmentation were greater than for any other scaffold. The bone area of TCP10 was 7.7-fold greater than that of non-treated scaffold. In contrast, TCP25 consistently exhibited adverse biological effects. These results suggest that the application dose of ß-TCP nanoparticles affects the scaffold bioproperties; consequently, the bone conductive ability of TCP10 was remarkable.


Subject(s)
Calcium Phosphates , Collagen , Nanoparticles , Tissue Scaffolds , Animals , Rats , Tissue Engineering
4.
Sci Rep ; 7: 45545, 2017 03 31.
Article in English | MEDLINE | ID: mdl-28361970

ABSTRACT

PCTAIRE kinase 3 (PCTK3) is a member of the cyclin dependent kinase family, but its physiological function remains unknown. We previously reported that PCTK3-knockdown HEK293T cells showed actin accumulation at the leading edge, suggesting that PCTK3 is involved in the regulation of actin reorganization. In this study, we investigated the physiological function and downstream signal transduction molecules of PCTK3. PCTK3 knockdown in HEK293T cells increased cell motility and RhoA/Rho-associated kinase activity as compared with control cells. We also found that phosphorylation at residue Tyr-397 in focal adhesion kinase (FAK) was increased in PCTK3-knockdown cells. FAK phosphorylation at Tyr-397 was increased in response to fibronectin stimulation, whereas its phosphorylation was suppressed by PCTK3. In addition, excessive expression of PCTK3 led to the formation of filopodia during the early stages of cell adhesion in HeLa cells. These results indicate that PCTK3 controls actin cytoskeleton dynamics by negatively regulating the FAK/Rho signaling pathway.


Subject(s)
Cell Adhesion/physiology , Cell Movement/physiology , Cyclin-Dependent Kinases/metabolism , Focal Adhesion Kinase 1/metabolism , Actin Cytoskeleton/metabolism , Actins/metabolism , Cell Line , Cell Line, Tumor , Focal Adhesion Protein-Tyrosine Kinases/metabolism , HEK293 Cells , HeLa Cells , Humans , Phosphorylation/physiology , Protein-Tyrosine Kinases/metabolism , Pseudopodia/metabolism , Signal Transduction/physiology , rho-Associated Kinases/metabolism , rhoA GTP-Binding Protein/metabolism
5.
Case Rep Oncol ; 8(1): 106-12, 2015.
Article in English | MEDLINE | ID: mdl-25848361

ABSTRACT

BACKGROUND: Primary sebaceous carcinoma of the parotid gland is extremely rare, and because of its rarity, clinicopathological characteristics and histogenesis are not fully understood. METHODS: Here, we report a patient who presented with a left infra-auricular painless mass. We present the histological features and discuss possible optimal treatments based on previous literature. RESULTS: The mass was suspected to be a myoepithelial tumor or possibly a pleomorphic adenoma. Initially, the mass was resected with preservation of the facial nerve, but this caused facial palsy. Because the histological examination showed a sebaceous carcinoma and a part of the mass could be remaining on the facial nerve, additional surgery was performed, and the facial nerve was reconstructed with cervical nerve. Follow-up after 7 months showed no sign of recurrence of metastasis. CONCLUSION: We encountered a rare sebaceous carcinoma of the parotid gland. Additional surgery was performed because preoperative diagnosis was difficult.

6.
Brain Res ; 1454: 23-32, 2012 May 15.
Article in English | MEDLINE | ID: mdl-22483791

ABSTRACT

Presbycusis is the impairment of auditory function associated with aging, which stems from peripheral cochlear lesions and degeneration of the central auditory process. The effect of age-induced peripheral hearing loss on the central auditory process is not fully understood. C57Bl/6 (C57) mice present accelerated peripheral hearing loss, which is well developed by middle-age and mimics the human presbycusis pattern. The aim of this study was to elucidate the molecular effects of peripheral hearing loss in the inferior colliculus (IC) with age between young and middle-aged C57 mice using cDNA microarray. Glutamate receptor ionotropic NMDA ζ1 (GluN1) exhibited the greatest decrease in the middle-aged group as determined using cDNA microarray and by further assessment using real-time PCR (qPCR). Histological assessment with in situ hybridization of GluN1 showed significantly decreased expression in all IC subdivisions of the middle-aged group. GluN1 is a receptor for excitatory neurotransmission, and significant downregulation of this gene may be subsequent to the decline of afferent input from the cochlea in aging C57 mice. Consequently, using the combination of microarray, qPCR, and in situ hybridization, we showed that the decline of GluN1 in the IC of aging animals might have a key role in the pathogenesis of presbycusis.


Subject(s)
Aging/metabolism , Down-Regulation/physiology , Inferior Colliculi/metabolism , Presbycusis/metabolism , Receptors, N-Methyl-D-Aspartate/metabolism , Aging/genetics , Aging/pathology , Animals , Cochlea/metabolism , Cochlea/pathology , Cochlea/physiopathology , Evoked Potentials, Auditory, Brain Stem/physiology , Female , Inferior Colliculi/physiopathology , Mice , Presbycusis/genetics , Presbycusis/physiopathology , Receptors, N-Methyl-D-Aspartate/genetics
8.
Hear Res ; 247(1): 17-26, 2009 Jan.
Article in English | MEDLINE | ID: mdl-18809482

ABSTRACT

Whereas most epithelial tissues turn-over and regenerate after a traumatic lesion, this restorative ability is diminished in the sensory epithelia of the inner ear; it is absent in the cochlea and exists only in a limited capacity in the vestibular epithelium. The extent of regeneration in vestibular hair cells has been characterized for several mammalian species including guinea pig, rat, and chinchilla, but not yet in mouse. As the fundamental model species for investigating hereditary disease, the mouse can be studied using a wide variety of genetic and molecular tools. To design a mouse model for vestibular hair cell regeneration research, an aminoglycoside-induced method of complete hair cell elimination was developed in our lab and applied to the murine utricle. Loss of utricular hair cells was observed using scanning electron microscopy, and corroborated by a loss of fluorescent signal in utricles from transgenic mice with GFP-positive hair cells. Regenerative capability was characterized at several time points up to six months following insult. Using scanning electron microscopy, we observed that as early as two weeks after insult, a few immature hair cells, demonstrating the characteristic immature morphology indicative of regeneration, could be seen in the utricle. As time progressed, larger numbers of immature hair cells could be seen along with some mature cells resembling surface morphology of type II hair cells. By six months post-lesion, numerous regenerated hair cells were present in the utricle, however, neither their number nor their appearance was normal. A BrdU assay suggested that at least some of the regeneration of mouse vestibular hair cells involved mitosis. Our results demonstrate that the vestibular sensory epithelium in mice can spontaneously regenerate, elucidate the time course of this process, and identify involvement of mitosis in some cases. These data establish a road map of the murine vestibular regenerative process, which can be used for elucidating the molecular events that govern this process.


Subject(s)
Anti-Bacterial Agents/adverse effects , Gentamicins/adverse effects , Hair Cells, Auditory/physiology , Hearing Loss/chemically induced , Regeneration/physiology , Saccule and Utricle/physiology , Animals , Anti-Bacterial Agents/pharmacology , Epithelial Cells/drug effects , Epithelial Cells/physiology , Epithelial Cells/ultrastructure , Gentamicins/pharmacology , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Hair Cells, Auditory/drug effects , Hair Cells, Auditory/ultrastructure , Hearing Loss/physiopathology , Male , Mice , Mice, Inbred CBA , Mice, Transgenic , Mitosis/drug effects , Models, Animal , Saccule and Utricle/cytology , Saccule and Utricle/drug effects
9.
J Gene Med ; 10(6): 610-8, 2008 Jun.
Article in English | MEDLINE | ID: mdl-18338819

ABSTRACT

BACKGROUND: Several genes are candidates for treating inner ear diseases. For clinical applications, minimally invasive approaches to the inner ear are desirable along with minimal side-effects. METHODS: Adeno-associated virus (AAV) was used as a vector into the guinea pig inner ear. Six AAV-cytomegalovirus hybrids (AAV-2/1, -2/2, -2/5, -2/7, -2/8 and -2/9) were infused into perilymph of the cochlea basal turn, an approach that could be used in cochlear implant surgery. At 7 days after injection, distribution of gene expression, hearing and morphology were evaluated. Adenoviral vector was also used to compare distributions of gene expression. Moreover, distribution of cell surface receptors of AAV in the cochlea was examined using immunohistochemistry. RESULTS: Using the perilymphatic approach, adenovirus could be transferred to mesothelial cells lining the perilymph, but not sensory cells. Conversely, all AAV serotypes displayed tissue tropism to inner hair cells, with AAV-2/2 showing particularly efficient transfer to sensory cells. This tissue tropism of AAV could not be explained by the distribution of AAV receptors. Hearing and morphology were largely unaffected. CONCLUSIONS: Our results indicate that AAV vector can be safely applied to the inner ear and AAV-2/2 offers a good tool for transferring transgenes into sensory cells of the inner ear efficiently without toxicity.


Subject(s)
Cochlear Diseases/therapy , Dependovirus/genetics , Gene Transfer Techniques , Genetic Therapy/methods , Genetic Vectors/genetics , Animals , Evoked Potentials, Auditory, Brain Stem/physiology , Gene Expression Profiling , Guinea Pigs , Hair Cells, Auditory, Inner/cytology , Hair Cells, Auditory, Inner/metabolism , Immunohistochemistry , Microscopy, Fluorescence
11.
Hear Res ; 232(1-2): 44-51, 2007 Oct.
Article in English | MEDLINE | ID: mdl-17658230

ABSTRACT

Sensorineural hearing loss, which is often caused by degeneration of hair cells in the auditory epithelium, is permanent because lost hair cells are not replaced. Several conceptual approaches can be used to place new hair cells in the auditory epithelium. One possibility is to enhance proliferation of non-sensory cells that remain in the deaf ear and induce transdifferentiation of some of these cells into the hair cell phenotype. Several genes, including p27(Kip1), have been shown to regulate proliferation and differentiation in the developing auditory epithelium. The role of p27(Kip1) in the mature ear is not well characterized. We now show that p27(Kip1) is present in the nuclei of non-sensory cells of the mature auditory epithelium. We determined that forced expression of Skp2 using a recombinant adenovirus vector, resulted in presence of BrdU-positive cells in the auditory epithelium. When SKP2 over-expression was combined with forced expression of Atoh1, ectopic hair cells were found in the auditory epithelium in greater numbers than were seen with Atoh1 alone. Skp2 over-expression alone did not result in ectopic hair cells. These findings suggest that the p27(Kip1) protein remains in the mature auditory epithelium and therefore p27(Kip1) can serve as a target for gene manipulation. The data also suggest that induced proliferation, by itself, does not generate new hair cells in the cochlea.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/metabolism , Cell Cycle , Cell Proliferation , Cochlea/metabolism , Cyclin-Dependent Kinase Inhibitor p27/metabolism , Hair Cells, Auditory/metabolism , Labyrinth Supporting Cells/metabolism , Adenoviridae/genetics , Animals , Basic Helix-Loop-Helix Transcription Factors/genetics , Cell Cycle/genetics , Cochlea/cytology , Cochlea/ultrastructure , Cyclin-Dependent Kinase Inhibitor p27/genetics , Gene Transfer Techniques , Genetic Vectors , Guinea Pigs , Hair Cells, Auditory/ultrastructure , Labyrinth Supporting Cells/ultrastructure , Time Factors
12.
Brain Res ; 1144: 74-81, 2007 May 04.
Article in English | MEDLINE | ID: mdl-17331482

ABSTRACT

Antidepressant treatments have been described to induce neurotrophic factors (NTFs) and reverse the cell loss observed in rodent stress models. Amitriptyline (AT), a tricyclic antidepressant agent, has been reported in recent studies to induce glial cell line-derived neurotrophic factor (GDNF) synthesis and release in rat C6 glioblastoma cells. GDNF has shown protection against acoustic trauma in previous studies. Therefore, we investigated whether AT could induce GDNF synthesis in the cochlea and attenuate cochlea damage against acoustic trauma. We used Hartley guinea pigs and injected AT (30 mg/kg) or saline into the peritoneum. Subjects were exposed to 117 dB SPL octave band noise centered at 4 kHz for 24 h. Noise-induced hearing loss (NIHL) was assessed with auditory brain stem response (ABR) at 4, 8 and 16 kHz measured prior to the injection, 3 days and 7 days after noise exposure. For histological assessment, we observed the sensory epithelium using a surface preparation technique and assessed the quantitative hair cell (HC) damage. We evaluated GDNF synthesis with or without intense noise exposure at 3, 12 and 24 h after the administration of AT in the cochlea using Western blot analysis. GDNF expression was shown 3 h and 12 h after the injection without noise, whereas with noise the GDNF expression lasted for 24 h. The AT-administrated group showed significantly reduced ABR threshold shift and less HC damage than the saline-administrated group. These findings suggest that the administration of AT-induced GDNF levels in the cochlea and attenuated cochlea damage from NIHL.


Subject(s)
Amitriptyline/administration & dosage , Analgesics, Non-Narcotic/administration & dosage , Gene Expression Regulation/drug effects , Glial Cell Line-Derived Neurotrophic Factor/metabolism , Hearing Loss, Noise-Induced/drug therapy , Animals , Auditory Threshold/drug effects , Disease Models, Animal , Evoked Potentials, Auditory, Brain Stem/drug effects , Evoked Potentials, Auditory, Brain Stem/physiology , Female , Gene Expression Regulation/physiology , Gene Expression Regulation/radiation effects , Guinea Pigs , Hair Cells, Auditory/drug effects , Hair Cells, Auditory/physiology , Hearing Loss, Noise-Induced/pathology , Hearing Loss, Noise-Induced/physiopathology
13.
Brain Res ; 1120(1): 93-9, 2006 Nov 20.
Article in English | MEDLINE | ID: mdl-17011530

ABSTRACT

Until now, there has been no effective therapy for chronic sensorineural hearing impairment. This study investigated the role of bone marrow cells (BMCs) in cochlear dysfunction. BALB/c mice (2 months of age), a non-presbycusis-prone mouse strain, were lethally irradiated and then transplanted with BMCs from SAMP1 mice (2 months of age), a presbycusis-prone mouse strain. Acceleration of age-related hearing loss, early degeneration of spiral ganglion cells (SGCs) and impairment of immune function were observed in the recipient mice as well as in the SAMP1 mice. However, no spiral ganglion cells of donor (SAMP1) origin were detected in the recipient mice. These results indicated that accelerated presbycusis, cochlear pathology, and immune dysfunction of SAMP1 mice can be transferred to BALB/c recipient mice using allogeneic bone marrow transplantation (BMT). However, although the BMCs themselves cannot differentiate into the spiral ganglion cells (SGCs), they indirectly cause the degeneration of the SGCs. Further studies into the relationship between the inner ear cells and BMCs are required.


Subject(s)
Aging/genetics , Bone Marrow Transplantation/methods , Hearing Loss, Sensorineural/genetics , Presbycusis/etiology , Animals , BALB 3T3 Cells , Bone Marrow Transplantation/immunology , Cell Count , Disease Models, Animal , Evoked Potentials, Auditory, Brain Stem/physiology , Fluorescent Antibody Technique/methods , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Mutant Strains , Nerve Degeneration/genetics , Nerve Degeneration/pathology , Presbycusis/immunology , Presbycusis/pathology , Presbycusis/physiopathology , Radiation Chimera , Spiral Ganglion/immunology , Spiral Ganglion/pathology , Spiral Ganglion/physiopathology
14.
Hear Res ; 214(1-2): 28-36, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16513305

ABSTRACT

p27(Kip1) (p27) has been shown to inhibit several cyclin-dependent kinase molecules and to play a central role in regulating entry into the cell cycle. Once hair cells in the cochlea are formed, p27 is expressed in non-sensory cells of the organ of Corti and prevents their re-entry into the cell cycle. In one line of p27 deficient mice (p27(-/-)), cell division in the organ of Corti continues past its normal embryonic time, leading to continual production of cells in the organ of Corti. Here we report on the structure and function of the inner ear in another line of p27 deficient mice originating from the Memorial Sloan-Kettering Cancer Center. The deficiency in p27 expression of these mice is incomplete, as they retain expression of amino acids 52-197. We determined that mice homozygote for this mutation had severe hearing loss and their organ of Corti exhibited an increase in the number of inner and outer hair cells. There also was a marked increase in the number of supporting cells, with severe pathologies in pillar cells. These data show similarities between this p27(Kip1) mutation and another, previously reported null allele of this gene, and suggest that reducing the inhibition on the cell cycle in the organ of Corti leads to pathology and dysfunction. Manipulations to regulate the time and place of p27 inhibition will be necessary for inducing functionally useful hair cell regeneration.


Subject(s)
Cochlear Diseases/etiology , Cyclin-Dependent Kinase Inhibitor p27/deficiency , Hearing Loss/etiology , Mutation , Organ of Corti/pathology , Animals , Cell Cycle/genetics , Cell Cycle/physiology , Cochlear Diseases/genetics , Cochlear Diseases/physiopathology , Cyclin-Dependent Kinase Inhibitor p27/genetics , Cyclin-Dependent Kinase Inhibitor p27/physiology , Evoked Potentials, Auditory, Brain Stem/physiology , Hair Cells, Auditory/diagnostic imaging , Hair Cells, Auditory/pathology , Hearing Loss/genetics , Hearing Loss/physiopathology , Image Processing, Computer-Assisted , Mice , Microscopy, Confocal , Microscopy, Electron , Microscopy, Electron, Scanning , Polymerase Chain Reaction , Ultrasonography
15.
J Acoust Soc Am ; 120(6): 3889-900, 2006 Dec.
Article in English | MEDLINE | ID: mdl-17225416

ABSTRACT

When sinusoidal electric stimulation is applied to the intact cochlea, a frequency-specific acoustic emission can be recorded in the ear canal. Acoustic emissions are produced by basilar membrane motion, and have been used to suggest a corresponding acoustic sensation termed "electromotile hearing." Electromotile hearing has been specifically attributed to electric stimulation of outer hair cells in the intact organ of Corti. To determine the nature of the auditory perception produced by electric stimulation of a cochlea with intact outer hair cells, guinea pigs were tested in a psychophysical task. First, subjects were trained to report detection of sinusoidal acoustic stimuli and dynamic range was assessed using response latency. Subjects were then implanted with a ball electrode placed into scala tympani. Following the surgical implant procedure, subjects were transferred to a task in which acoustic signals were replaced by sinusoidal electric stimulation, and dynamic range was assessed again. Finally, the ability of acoustic pure-tone stimuli to mask the detection of the electric signals was assessed. Based on the masking effects, it is concluded that sinusoidal electric stimulation of the intact cochlea results in perception of a tonal (rather than a broadband or noisy) sound at a frequency of 8 kHz or above.


Subject(s)
Cochlea/physiology , Hearing/physiology , Perceptual Masking/physiology , Radio Waves , Acoustics , Animals , Electric Stimulation/instrumentation , Guinea Pigs , Otoacoustic Emissions, Spontaneous/physiology , Psychophysics/statistics & numerical data
16.
Nat Med ; 11(3): 271-6, 2005 Mar.
Article in English | MEDLINE | ID: mdl-15711559

ABSTRACT

In the mammalian auditory system, sensory cell loss resulting from aging, ototoxic drugs, infections, overstimulation and other causes is irreversible and leads to permanent sensorineural hearing loss. To restore hearing, it is necessary to generate new functional hair cells. One potential way to regenerate hair cells is to induce a phenotypic transdifferentiation of nonsensory cells that remain in the deaf cochlea. Here we report that Atoh1, a gene also known as Math1 encoding a basic helix-loop-helix transcription factor and key regulator of hair cell development, induces regeneration of hair cells and substantially improves hearing thresholds in the mature deaf inner ear after delivery to nonsensory cells through adenovectors. This is the first demonstration of cellular and functional repair in the organ of Corti of a mature deaf mammal. The data suggest a new therapeutic approach based on expressing crucial developmental genes for cellular and functional restoration in the damaged auditory epithelium and other sensory systems.


Subject(s)
DNA-Binding Proteins/genetics , Genetic Therapy/methods , Hair Cells, Auditory/physiology , Hearing Loss, Sensorineural/therapy , Nerve Tissue Proteins/genetics , Transcription Factors/genetics , Adenoviridae/genetics , Animals , Cochlea/pathology , DNA-Binding Proteins/biosynthesis , Ethacrynic Acid , Gene Expression Regulation, Developmental , Guinea Pigs , Hair Cells, Auditory/growth & development , Hearing Loss, Sensorineural/chemically induced , Helix-Loop-Helix Motifs , Kanamycin , Nerve Regeneration , Nerve Tissue Proteins/biosynthesis , Transcription Factors/biosynthesis
17.
J Acoust Soc Am ; 116(2): 1044-56, 2004 Aug.
Article in English | MEDLINE | ID: mdl-15376671

ABSTRACT

Brief cochlear excitotoxicity produces temporary neural swelling and transient deficits in auditory sensitivity; however, the consequences of long-lasting excitotoxic insult have not been tested. Chronic intra-cochlear infusion of the glutamate agonist AMPA (a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) resulted in functional deficits in the sound-evoked auditory brainstem response, as well as in behavioral measures of hearing. The electrophysiological deficits were similar to those observed following acute infusion of AMPA into the cochlea; however, the concentration-response curve was significantly shifted as a consequence of the slower infusion rate used with chronic cochlear administration. As observed following acute excitotoxic insult, complete functional recovery was evident within 7 days of discontinuing the AMPA infusion. Distortion product otoacoustic emissions were not affected by chronic AMPA infusion, suggesting that trauma to outer hair cells did not contribute to AMPA-induced deficits in acoustic sensitivity. Results from the current experiment address the permanence of deficits induced by chronic (14 day) excitotoxic insult as well as deficits in psychophysical detection of longer duration acoustic signals.


Subject(s)
Cochlea/drug effects , Cochlear Nerve/drug effects , Excitatory Amino Acid Agonists/toxicity , Hearing Loss, Sensorineural/chemically induced , alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/toxicity , Animals , Audiometry, Evoked Response , Auditory Threshold/drug effects , Cochlea/pathology , Cochlea/physiology , Evoked Potentials, Auditory, Brain Stem/drug effects , Excitatory Amino Acid Agonists/pharmacology , Female , Guinea Pigs , Hair Cells, Auditory, Outer/drug effects , Male , Neomycin/pharmacology , Otoacoustic Emissions, Spontaneous/drug effects , Otoacoustic Emissions, Spontaneous/physiology , Protein Synthesis Inhibitors/pharmacology , alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid/pharmacology
18.
Neuroreport ; 15(7): 1089-92, 2004 May 19.
Article in English | MEDLINE | ID: mdl-15129151

ABSTRACT

The auditory sensory epithelium is a mosaic composed of sensory (hair) cells and several types of non-sensory (supporting) cells. All these cells are highly differentiated in their structure and function. Mosaic epithelia (and other complex tissues) are generally formed by differentiation of distinct and specialized cell types from common progenitors. Most types of epithelial tissues maintain a population of undifferentiated (basal) cells which facilitate turnover (renewal) and repair, but this is not the case for the organ of Corti in the cochlea. Therefore, when cochlear hair cells are lost they cannot be replaced. Consequently, sensorineural hearing loss is permanent. In designing therapy for sensorineural deafness, the most important task is to find a way to generate new cochlear hair cells to replace lost cells.


Subject(s)
Hair Cells, Auditory/cytology , Hair Cells, Auditory/metabolism , Hearing Loss, Sensorineural/metabolism , Hearing Loss, Sensorineural/therapy , Animals , Basic Helix-Loop-Helix Transcription Factors , Cell Differentiation/physiology , Cochlea , Hair Cells, Auditory/transplantation , Humans , Transcription Factors/biosynthesis
19.
Audiol Neurootol ; 9(3): 135-43, 2004.
Article in English | MEDLINE | ID: mdl-15084818

ABSTRACT

Hair cell loss, the most common cause of deafness, is often associated with auditory nerve degeneration. Our goal was to determine the influence of combined ciliary-derived neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) gene therapy on the survival of spiral ganglion neurons (SGNs) after elimination of inner hair cells in the mature guinea pig ear. Seven days after bilateral deafening, a 5-microl suspension of CNTF and/or BDNF adenovirus vectors was injected into the left scala tympani through the round window. Animals were sacrificed 28 days after deafening, and their inner ears were prepared for SGN counts. The SGN counts revealed that BDNF alone and the combined CNTF and BDNF treatment significantly enhanced SGN survival. CNTF did not significantly enhance the protective effect of BDNF. These data present possible strategies for enhancing SGN survival in cochlear implant procedures.


Subject(s)
Brain-Derived Neurotrophic Factor/genetics , Genetic Therapy/methods , Hearing Loss, Sensorineural/prevention & control , Nerve Degeneration/prevention & control , Neurons, Afferent/physiology , Spiral Ganglion/physiology , Adenoviridae , Animals , Brain-Derived Neurotrophic Factor/metabolism , Cell Survival/drug effects , Ciliary Neurotrophic Factor/genetics , Ciliary Neurotrophic Factor/metabolism , Gene Expression , Genetic Vectors , Guinea Pigs , Hair Cells, Auditory/pathology , Neurons, Afferent/drug effects , Spiral Ganglion/cytology , Spiral Ganglion/drug effects
20.
Mol Ther ; 9(2): 173-81, 2004 Feb.
Article in English | MEDLINE | ID: mdl-14759801

ABSTRACT

Aminoglycosides are commonly used antibiotics that often induce ototoxicity leading to permanent hair cell loss and hearing impairment. The ototoxic effects of aminoglycosides have been linked to oxidative stress. To determine the feasibility of antioxidant gene therapy for protecting the inner ear against aminoglycoside-induced oxidative stress, we used adenoviral vectors for overexpression of catalase, Cu/Zn superoxide dismutase (SOD1), and Mn superoxide dismutase (SOD2). We inoculated adenoviruses designated Ad.cat, Ad.SOD1, and Ad.SOD2 into the left guinea pig cochlea. Five days later, an ototoxic combination of kanamycin and ethacrynic acid was systemically administered. Artificial perilymph and adenovirus without a gene cassette (Ad.null) were used as controls. Biochemical analysis showed significant increase in catalase and a moderate elevation in SOD2 levels in tissues of the cochlea inoculated with the respective vectors. Auditory brain-stem responses were measured to monitor hearing thresholds. Animals were sacrificed 7 days after the ototoxic insult and their hair cells counted. Hair cells and hearing thresholds were significantly protected by Ad.cat and Ad.SOD2, while results with Ad.SOD1 were inconsistent. Control ears showed no significant protective effects. The results demonstrate that the expression of functional enzymes in the inner ear is feasible using adenoviral-mediated gene delivery. Furthermore, they confirm that reactive oxygen species contribute to aminoglycoside ototoxicity and suggest antioxidant gene therapy as a potential therapeutic strategy to reduce inner ear oxidative stress.


Subject(s)
Antioxidants/metabolism , Catalase/therapeutic use , Genetic Therapy , Hair Cells, Auditory/metabolism , Hearing/physiology , Superoxide Dismutase/therapeutic use , Adenoviridae/genetics , Animals , Catalase/genetics , Cochlea/cytology , Cochlea/physiology , Genetic Vectors/genetics , Guinea Pigs , Superoxide Dismutase/genetics
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