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Vecchi JT, Claussen AD, Hansen MR. Decreasing the physical gap in the neural-electrode interface and related concepts to improve cochlear implant performance. Front Neurosci 2024; 18:1425226. [PMID: 39114486 PMCID: PMC11303154 DOI: 10.3389/fnins.2024.1425226] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/11/2024] [Indexed: 08/10/2024] Open
Abstract
Cochlear implants (CI) represent incredible devices that restore hearing perception for those with moderate to profound sensorineural hearing loss. However, the ability of a CI to restore complex auditory function is limited by the number of perceptually independent spectral channels provided. A major contributor to this limitation is the physical gap between the CI electrodes and the target spiral ganglion neurons (SGNs). In order for CI electrodes to stimulate SGNs more precisely, and thus better approximate natural hearing, new methodologies need to be developed to decrease this gap, (i.e., transitioning CIs from a far-field to near-field device). In this review, strategies aimed at improving the neural-electrode interface are discussed in terms of the magnitude of impact they could have and the work needed to implement them. Ongoing research suggests current clinical efforts to limit the CI-related immune response holds great potential for improving device performance. This could eradicate the dense, fibrous capsule surrounding the electrode and enhance preservation of natural cochlear architecture, including SGNs. In the long term, however, optimized future devices will likely need to induce and guide the outgrowth of the peripheral process of SGNs to be in closer proximity to the CI electrode in order to better approximate natural hearing. This research is in its infancy; it remains to be seen which strategies (surface patterning, small molecule release, hydrogel coating, etc.) will be enable this approach. Additionally, these efforts aimed at optimizing CI function will likely translate to other neural prostheses, which face similar issues.
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Affiliation(s)
- Joseph T. Vecchi
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, Iowa City, IA, United States
- Department of Otolaryngology Head-Neck Surgery, Carver College of Medicine, Iowa City, IA, United States
| | - Alexander D. Claussen
- Department of Otolaryngology Head-Neck Surgery, Carver College of Medicine, Iowa City, IA, United States
| | - Marlan R. Hansen
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, Iowa City, IA, United States
- Department of Otolaryngology Head-Neck Surgery, Carver College of Medicine, Iowa City, IA, United States
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2
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Ding D, Manohar S, Kador PF, Salvi R. Multifunctional redox modulator prevents blast-induced loss of cochlear and vestibular hair cells and auditory spiral ganglion neurons. Sci Rep 2024; 14:15296. [PMID: 38961203 PMCID: PMC11222375 DOI: 10.1038/s41598-024-66406-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 07/01/2024] [Indexed: 07/05/2024] Open
Abstract
Blast wave exposure, a leading cause of hearing loss and balance dysfunction among military personnel, arises primarily from direct mechanical damage to the mechanosensory hair cells and supporting structures or indirectly through excessive oxidative stress. We previously reported that HK-2, an orally active, multifunctional redox modulator (MFRM), was highly effective in reducing both hearing loss and hair cells loss in rats exposed to a moderate intensity workday noise that likely damages the cochlea primarily from oxidative stress versus direct mechanical trauma. To determine if HK-2 could also protect cochlear and vestibular cells from damage caused primarily from direct blast-induced mechanical trauma versus oxidative stress, we exposed rats to six blasts of 186 dB peak SPL. The rats were divided into four groups: (B) blast alone, (BEP) blast plus earplugs, (BHK-2) blast plus HK-2 and (BEPHK-2) blast plus earplugs plus HK-2. HK-2 was orally administered at 50 mg/kg/d from 7-days before to 30-day after the blast exposure. Cochlear and vestibular tissues were harvested 60-d post-exposure and evaluated for loss of outer hair cells (OHC), inner hair cells (IHC), auditory nerve fibers (ANF), spiral ganglion neurons (SGN) and vestibular hair cells in the saccule, utricle and semicircular canals. In the untreated blast-exposed group (B), massive losses occurred to OHC, IHC, ANF, SGN and only the vestibular hair cells in the striola region of the saccule. In contrast, rats treated with HK-2 (BHK-2) sustained significantly less OHC (67%) and IHC (57%) loss compared to the B group. OHC and IHC losses were smallest in the BEPHK-2 group, but not significantly different from the BEP group indicating lack of protective synergy between EP and HK-2. There was no loss of ANF, SGN or saccular hair cells in the BHK-2, BEP and BEPHK-2 groups. Thus, HK-2 not only significantly reduced OHC and IHC damage, but completely prevented loss of ANF, SGN and saccule hair cells. The powerful protective effects of this oral MFRM make HK-2 an extremely promising candidate for human clinical trials.
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Affiliation(s)
- Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA
| | | | | | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA.
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Lye J, Delaney DS, Leith FK, Sardesai VS, McLenachan S, Chen FK, Atlas MD, Wong EYM. Recent Therapeutic Progress and Future Perspectives for the Treatment of Hearing Loss. Biomedicines 2023; 11:3347. [PMID: 38137568 PMCID: PMC10741758 DOI: 10.3390/biomedicines11123347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/06/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023] Open
Abstract
Up to 1.5 billion people worldwide suffer from various forms of hearing loss, with an additional 1.1 billion people at risk from various insults such as increased consumption of recreational noise-emitting devices and ageing. The most common type of hearing impairment is sensorineural hearing loss caused by the degeneration or malfunction of cochlear hair cells or spiral ganglion nerves in the inner ear. There is currently no cure for hearing loss. However, emerging frontier technologies such as gene, drug or cell-based therapies offer hope for an effective cure. In this review, we discuss the current therapeutic progress for the treatment of hearing loss. We describe and evaluate the major therapeutic approaches being applied to hearing loss and summarize the key trials and studies.
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Affiliation(s)
- Joey Lye
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA 6009, Australia; (J.L.); (D.S.D.); (F.K.L.); (V.S.S.); (M.D.A.)
- Centre for Ear Sciences, Medical School, The University of Western Australia, Nedlands, WA 6009, Australia
| | - Derek S. Delaney
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA 6009, Australia; (J.L.); (D.S.D.); (F.K.L.); (V.S.S.); (M.D.A.)
- Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA 6102, Australia
| | - Fiona K. Leith
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA 6009, Australia; (J.L.); (D.S.D.); (F.K.L.); (V.S.S.); (M.D.A.)
- Centre for Ear Sciences, Medical School, The University of Western Australia, Nedlands, WA 6009, Australia
| | - Varda S. Sardesai
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA 6009, Australia; (J.L.); (D.S.D.); (F.K.L.); (V.S.S.); (M.D.A.)
| | - Samuel McLenachan
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, WA 6009, Australia; (S.M.); (F.K.C.)
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, WA 6009, Australia
| | - Fred K. Chen
- Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, WA 6009, Australia; (S.M.); (F.K.C.)
- Centre for Ophthalmology and Visual Sciences, The University of Western Australia, Nedlands, WA 6009, Australia
- Vitroretinal Surgery, Royal Perth Hospital, Perth, WA 6000, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC 3002, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC 3002, Australia
| | - Marcus D. Atlas
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA 6009, Australia; (J.L.); (D.S.D.); (F.K.L.); (V.S.S.); (M.D.A.)
- Centre for Ear Sciences, Medical School, The University of Western Australia, Nedlands, WA 6009, Australia
| | - Elaine Y. M. Wong
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA 6009, Australia; (J.L.); (D.S.D.); (F.K.L.); (V.S.S.); (M.D.A.)
- Centre for Ear Sciences, Medical School, The University of Western Australia, Nedlands, WA 6009, Australia
- Curtin Medical School, Faculty of Health Sciences, Curtin University, Bentley, WA 6102, Australia
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Zhao J, Yu HQ, Ge FQ, Zhang MR, Song YC, Guo DD, Li QH, Zhu H, Hang PZ. 7,8,3'-Trihydroxyflavone prevents doxorubicin-induced cardiotoxicity and mitochondrial dysfunction via activating Akt signaling pathway in H9c2 cells. Cell Signal 2023; 112:110924. [PMID: 37838311 DOI: 10.1016/j.cellsig.2023.110924] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/27/2023] [Accepted: 10/09/2023] [Indexed: 10/16/2023]
Abstract
Clinical application of the widely used chemotherapeutic agent, doxorubicin (DOX), is limited by its cardiotoxicity. Mitochondrial dysfunction has been revealed as a crucial factor in DOX-induced cardiotoxicity. 7,8,3'-Trihydroxyflavone (THF) is a mimetic brain-derived neurotrophic factor with neuroprotective effects. However, the potential effects of THF on DOX-induced cardiomyocyte damage and mitochondrial disorders remain unclear. H9c2 cardiomyoblasts were exposed to DOX and/or THF at different concentrations. Cardiomyocyte injury was evaluated using lactate dehydrogenase (LDH) assay and Live/Dead cytotoxicity kit. Meanwhile, mitochondrial membrane potential (MMP), morphology, mitochondrial reactive oxygen species (mito-ROS) production, and the oxygen consumption rate of cardiomyocytes were measured. The protein levels of key mitochondria-related factors such as adenosine monophosphate-activated protein kinase (AMPK), mitofusin 2 (Mfn2), dynamin-related protein 1 (Drp1), and optic atrophy protein 1 (OPA1) were examined. We found that THF reduced LDH content and death ratio of DOX-treated cardiomyocytes in a concentration-dependent manner, while increasing MMP without significantly affecting the routine and maximum capacity of mitochondrial respiration. Mechanistically, THF increased the activity of Akt and protein levels of Mfn2 and heme oxygenase 1 (HO-1). Moreover, inhibition of Akt reversed the protective role of THF, increased mito-ROS levels, and repressed Mfn2 and HO-1 expression. Therefore, we conclude, THF relieves DOX-induced cardiotoxicity and improves mitochondrial function by activating Akt-mediated Mfn2 and HO-1 pathways. This finding provides promising therapeutic insights for DOX-induced cardiac dysfunction.
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Affiliation(s)
- Jing Zhao
- Department of Pharmacy, Clinical Medical College, Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou 225001, China
| | - Hua-Qing Yu
- Department of Pharmacy, Clinical Medical College, Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou 225001, China; College of Pharmacy, Dalian Medical University, Dalian 116044, China
| | - Feng-Qin Ge
- Department of Pharmacy, Clinical Medical College, Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou 225001, China; Medical College, Yangzhou University, Yangzhou 225009, China
| | - Man-Ru Zhang
- Department of Pharmacy, Clinical Medical College, Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou 225001, China; College of Pharmacy, Dalian Medical University, Dalian 116044, China
| | - Yu-Chen Song
- Department of Pharmacy, Clinical Medical College, Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou 225001, China; Medical College, Yangzhou University, Yangzhou 225009, China
| | - Dan-Dan Guo
- Department of Pharmacy, Clinical Medical College, Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou 225001, China; Medical College, Yangzhou University, Yangzhou 225009, China
| | - Qi-Hang Li
- Department of Pharmacy, Clinical Medical College, Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou 225001, China; Medical College, Yangzhou University, Yangzhou 225009, China
| | - Hua Zhu
- Department of Pharmacy, Clinical Medical College, Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou 225001, China.
| | - Peng-Zhou Hang
- Department of Pharmacy, Clinical Medical College, Yangzhou University, Northern Jiangsu People's Hospital, Yangzhou 225001, China.
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Vink HA, Ramekers D, Foster AC, Versnel H. The efficacy of a TrkB monoclonal antibody agonist in preserving the auditory nerve in deafened guinea pigs. Hear Res 2023; 439:108895. [PMID: 37837701 DOI: 10.1016/j.heares.2023.108895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 08/31/2023] [Accepted: 10/02/2023] [Indexed: 10/16/2023]
Abstract
The auditory nerve typically degenerates following loss of cochlear hair cells or synapses. In the case of hair cell loss neural degeneration hinders restoration of hearing through a cochlear implant, and in the case of synaptopathy suprathreshold hearing is affected, potentially degrading speech perception in noise. It has been established that neurotrophins such as brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) can mitigate auditory nerve degeneration. Several potential BDNF mimetics have also been investigated for neurotrophic effects in the cochlea. A recent in vitro study showed favorable effects of M3, a TrkB monoclonal antibody agonist, when compared with BDNF. In the present study we set out to examine the effect of M3 on auditory nerve preservation in vivo. Thirty-one guinea pigs were bilaterally deafened, and unilaterally treated with a single 3-µl dose of 7 mg/ml, 0.7 mg/ml M3 or vehicle-only by means of a small gelatin sponge two weeks later. During the experiment and analyses the experimenters were blinded to the three treatment groups. Four weeks after treatment, we assessed the treatment effect (1) histologically, by quantifying survival of SGCs and their peripheral processes (PPs); and (2) electrophysiologically, with two different paradigms of electrically evoked compound action potential (eCAP) recordings shown to be indicative of neural health: single-pulse stimulation with varying inter-phase gap (IPG), and pulse-train stimulation with varying inter-pulse interval. We observed a consistent and significant preservative effect of M3 on SGC survival in the lower basal turn (approximately 40% more survival than in the untreated contralateral cochlea), but also in the upper middle and lower apical turn of the cochlea. This effect was similar for the two treatment groups. Survival of PPs showed a trend similar to that of the SGCs, but was only significantly higher for the highest dose of M3. The protective effect of M3 on SGCs was not reflected in any of the eCAP measures: no statistically significant differences were observed between groups in IPG effect nor between the M3 treatment groups and the control group using the pulse-train stimulation paradigm. In short, while a clear effect of M3 was observed on SGC survival, this was not clearly translated into functional preservation.
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Affiliation(s)
- Henk A Vink
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Room G.02.531, P.O. Box 85500, 3508 GA, Utrecht, the Netherlands; UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands
| | - Dyan Ramekers
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Room G.02.531, P.O. Box 85500, 3508 GA, Utrecht, the Netherlands; UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands
| | | | - Huib Versnel
- Department of Otorhinolaryngology and Head & Neck Surgery, University Medical Center Utrecht, Utrecht University, Room G.02.531, P.O. Box 85500, 3508 GA, Utrecht, the Netherlands; UMC Utrecht Brain Center, Utrecht University, Utrecht, the Netherlands.
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6
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Kempfle JS, Jung DH. Experimental drugs for the prevention or treatment of sensorineural hearing loss. Expert Opin Investig Drugs 2023; 32:643-654. [PMID: 37598357 DOI: 10.1080/13543784.2023.2242253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 07/26/2023] [Indexed: 08/22/2023]
Abstract
INTRODUCTION Sensorineural hearing loss results in irreversible loss of inner ear hair cells and spiral ganglion neurons. Reduced sound detection and speech discrimination can span all ages, and sensorineural hearing rehabilitation is limited to amplification with hearing aids or cochlear implants. Recent insights into experimental drug treatments for inner ear regeneration and otoprotection have paved the way for clinical trials in order to restore a more physiological hearing experience. Paired with the development of innovative minimally invasive approaches for drug delivery to the inner ear, new, emerging treatments for hearing protection and restoration are within reach. AREAS COVERED This expert opinion provides an overview of the latest experimental drug therapies to protect from and to restore sensorineural hearing loss. EXPERT OPINION The degree and type of cellular damage to the cochlea, the responsiveness of remaining, endogenous cells to regenerative treatments, and the duration of drug availability within cochlear fluids will determine the success of hearing protection or restoration.
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Affiliation(s)
- Judith S Kempfle
- Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Otolaryngology, Head & Neck Surgery, Harvard Medical School, Boston, MA, USA
- Department of Otolaryngology, UMass Memorial Medical Center, Worcester, MA, USA
- Department of Otolaryngology, Head & Neck Surgery, University of Massachusetts Medical School, Worcester, MA, USA
| | - David H Jung
- Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Otolaryngology, Head & Neck Surgery, Harvard Medical School, Boston, MA, USA
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Cutri RM, Lin J, Nguyen NV, Shakya D, Shibata SB. Neomycin-Induced Deafness in Neonatal Mice. J Neurosci Methods 2023; 391:109852. [PMID: 37031766 DOI: 10.1016/j.jneumeth.2023.109852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 03/26/2023] [Accepted: 04/06/2023] [Indexed: 04/11/2023]
Abstract
BACKGROUND Hearing impairment is a rising public health issue, and current therapeutics fail to restore normal auditory sensation. Animal models are essential to a better understanding of the pathophysiology of deafness and developing therapeutics to restore hearing. NEW METHODS Wild-type CBA/CaJ neonatal mice P2-5 were used in this study. Neomycin suspension (500nl of 50 or 100mg/ml) was micro-injected into the endolymphatic space. Cochlear morphology was examined 3 and 7 days after injection; hair cell (HC) loss, supporting cell morphology, and neurite denervation pattern were assessed with whole-mounts. At 2 and 4 weeks post-injection, the spiral ganglion neuron (SGN) density was analyzed with cryostat sections. Audiometric responses were measured with auditory brain response (ABR) at 4 weeks. RESULTS Rapid and complete degeneration of the inner and outer HCs occurred as early as 3 days post-injection. Subsequently, time- and dose-dependent degeneration patterns were observed along the axis of the cochlear membranous labyrinth forming a flat epithelium. Likewise, the SGN histology demonstrated significant cell density reduction at 2 and 4 weeks. The ABR threshold measurements confirmed profound deafness at 4 weeks. COMPARISON WITH EXISTING METHODS Compared to previously described local and systemic aminoglycoside injections, this method provides a reliable, robust, and rapid deafening model with a single infusion of neomycin in neonatal mice. This model also allows for investigating the effects of inner ear damage during auditory maturation. CONCLUSIONS A single injection of neomycin into the endolymphatic space induces robust HC loss and denervation in neonatal mice.
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Affiliation(s)
- Raffaello M Cutri
- Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Joshua Lin
- Keck School of Medicine of University of Southern California, Los Angeles, CA 90033, USA
| | - Nhi V Nguyen
- Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA
| | - Dejan Shakya
- Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089, USA
| | - Seiji B Shibata
- Caruso Department of Otolaryngology-Head and Neck Surgery, University of Southern California, Los Angeles, CA 90033, USA.
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Oral Administration of TrkB Agonist, 7, 8-Dihydroxyflavone Regenerates Hair Cells and Restores Function after Gentamicin-Induced Vestibular Injury in Guinea Pig. Pharmaceutics 2023; 15:pharmaceutics15020493. [PMID: 36839815 PMCID: PMC9966733 DOI: 10.3390/pharmaceutics15020493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/24/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
The causes of vestibular dysfunction include the loss of hair cells (HCs), synapses beneath the HCs, and nerve fibers. 7, 8-dihydroxyflavone (DHF) mimics the physiological functions of brain-derived neurotrophic factor. We investigated the effects of the orally-administered DHF in the guinea pig crista ampullaris after gentamicin (GM)-induced injury. Twenty animals treated with GM received daily administration of DHF or saline for 14 or 28 days (DHF (+) or DHF (-) group; N = 5, each). At 14 days after GM treatment, almost all of the HCs had disappeared in both groups. At 28 days, the HCs number in DHF (+) and DHF (-) groups was 74% and 49%, respectively, compared to GM-untreated control. In the ampullary nerves, neurofilament 200 positive rate in the DHF (+) group was 91% at 28 days, which was significantly higher than 42% in DHF (-). On day 28, the synaptic connections observed between C-terminal-binding protein 2-positive and postsynaptic density protein-95-positive puncta were restored, and caloric response was significantly improved in DHF (+) group (canal paresis: 57.4% in DHF (+) and 100% in DHF (-)). Taken together, the oral administration of DHF may be a novel therapeutic approach for treating vestibular dysfunction in humans.
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Manohar S, Ding D, Jiang H, Li L, Chen GD, Kador P, Salvi R. Combined antioxidants and anti-inflammatory therapies fail to attenuate the early and late phases of cyclodextrin-induced cochlear damage and hearing loss. Hear Res 2021; 414:108409. [PMID: 34953289 DOI: 10.1016/j.heares.2021.108409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 09/08/2021] [Accepted: 12/06/2021] [Indexed: 11/04/2022]
Abstract
Niemann-Pick C1 (NPC1) is a fatal neurodegenerative disease caused by aberrant cholesterol metabolism. The progression of the disease can be slowed by removing excess cholesterol with high-doses of 2-hyroxypropyl-beta-cyclodextrin (HPβCD). Unfortunately, HPβCD causes hearing loss; the initial first phase involves a rapid destruction of outer hair cells (OHCs) while the second phase, occurring 4-6 weeks later, involves the destruction of inner hair cells (IHCs), pillar cells, collapse of the organ of Corti and spiral ganglion neuron degeneration. To determine whether the first and/or second phase of HPβCD-induced cochlear damage is linked, in part, to excess oxidative stress or neuroinflammation, rats were treated with a single-dose of 3000 mg/kg HPβCD alone or together with one of two combination therapies. Each combination therapy was administered from 2-days before to 6-weeks after the HPβCD treatment. Combination 1 consisted of minocycline, an antibiotic that suppresses neuroinflammation, and HK-2, a multifunctional redox modulator that suppresses oxidative stress. Combination 2 was comprised of minocycline plus N-acetyl cysteine (NAC), which upregulates glutathione, a potent antioxidant. To determine if either combination therapy could prevent HPβCD-induced hearing impairment and cochlear damage, distortion product otoacoustic emissions (DPOAE) were measured to assess OHC function and the cochlear compound action potential (CAP) was measured to assess the function of IHCs and auditory nerve fibers. Cochleograms were prepared to quantify the amount of OHC, IHC and pillar cell (PC) loss. HPβCD significantly reduced DPOAE and CAP amplitudes and caused significant OHC, IHC and OPC losses with losses greater in the high-frequency base of the cochlea than the apex. Neither minocycline + HK-2 (MIN+ HK-2) nor minocycline + NAC (MIN+NAC) prevented the loss of DPOAEs, CAPs, OHCs, IHCs or IPCs caused by HPβCD. These results suggest that oxidative stress and neuroinflammation are unlikely to play major roles in mediating the first or second phase of HPβCD-induced cochlear damage. Thus, HPβCD-induced ototoxicity must be mediated by some other unknown cell-death pathway possibly involving loss of trophic support from damaged support cells or disrupted cholesterol metabolism.
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Affiliation(s)
- Senthilvelan Manohar
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Dalian Ding
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Haiyan Jiang
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Li Li
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Guang-Di Chen
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Peter Kador
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA
| | - Richard Salvi
- Center for Hearing and Deafness, University at Buffalo, Buffalo, NY, 14214, USA; Department of Pharmaceutical Sciences, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, 68198, USA; Therapeutic Vision, Inc., Elkhorn, NE, 68022, USA.
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10
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Kempfle JS. Endoscopic-Assisted Drug Delivery for Inner Ear Regeneration. Otolaryngol Clin North Am 2021; 54:189-200. [PMID: 33243375 DOI: 10.1016/j.otc.2020.09.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Sensorineural hearing loss is caused by irreversible loss of auditory hair cells and/or neurons and is increasing in prevalence. Hair cells and neurons do not regenerate after damage, but novel regeneration therapies based on small molecule drugs, gene therapy, and cell replacement strategies offer promising therapeutic options. Endogenous and exogenous regeneration techniques are discussed in context of their feasibility for hair cell and neuron regeneration. Gene therapy and treatment of synaptopathy represent promising future therapies. Minimally invasive endoscopic ear surgery offers a viable approach to aid in delivery of pharmacologic compounds, cells, or viral vectors to the inner ear for all of these techniques.
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Affiliation(s)
- Judith S Kempfle
- Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Eaton-Peabody Laboratories, C360, 243 Charles Street, Boston, MA 02114, USA.
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11
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Sarkar P, Jayaraj P, Patwardhan K, Yeole S, Das S, Somaiya Y, Desikan R, Thirumurugan K. In Silico Analysis to Link Insulin Resistance, Obesity and Ageing with Alzheimer's Disease. J Mol Neurosci 2021; 71:2608-2617. [PMID: 34227035 DOI: 10.1007/s12031-021-01875-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 06/16/2021] [Indexed: 01/09/2023]
Abstract
The process of ageing accompanies several metabolic diseases. With ageing, fats accumulate to increase the visceral and abdominal adiposity leading to hyperinsulinemia, insulin resistance, obesity and several other diseases. Drosophila melanogaster is often used to study the ageing process and its related disorders. Therefore, in this study, we performed an in silico analysis to relate the process of ageing and insulin resistance. We analysed the data of insulin-resistant Drosophila from the GEO database and compared it with the data from the literature survey. We observed that 98 genes were common in both the models, and they showed gene modulations related to metabolic pathways, fatty acid metabolism, insulin resistance and neural receptor-ligand binding pathways. Analysis of the REACTOME database against human data revealed that the TRKB signalling pathway is commonly affected. The TRKB-mediated BDNF pathway is a major regulator of memory loss. We further analysed the common genes in Alzheimer's disease and compared the fly data with human data to identify the diseases related to these common genes. Then, we performed a literature survey to provide protective mechanisms for the TRKB signalling pathway activation, mediated through polyphenols. We treated the flies with sesamol-conjugated lipoic acid derivative (a phenolic compound) at hormetic doses to evaluate its effect on the memory of flies.
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Affiliation(s)
- Priyanka Sarkar
- Structural Biology Lab, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, 632014, India
| | - Premkumar Jayaraj
- Technology Tower, Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632014, India
| | - Ketaki Patwardhan
- Structural Biology Lab, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, 632014, India
| | - Samiksha Yeole
- Structural Biology Lab, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, 632014, India
| | - Sourajit Das
- Structural Biology Lab, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, 632014, India
| | - Yash Somaiya
- Structural Biology Lab, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, 632014, India
| | - Rajagopal Desikan
- Technology Tower, Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology, Vellore, 632014, India
| | - Kavitha Thirumurugan
- Structural Biology Lab, School of Biosciences & Technology, Vellore Institute of Technology, Vellore, 632014, India.
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12
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Fernandez KA, Watabe T, Tong M, Meng X, Tani K, Kujawa SG, Edge AS. Trk agonist drugs rescue noise-induced hidden hearing loss. JCI Insight 2021; 6:142572. [PMID: 33373328 PMCID: PMC7934864 DOI: 10.1172/jci.insight.142572] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 12/16/2020] [Indexed: 12/21/2022] Open
Abstract
TrkB agonist drugs are shown here to have a significant effect on the regeneration of afferent cochlear synapses after noise-induced synaptopathy. The effects were consistent with regeneration of cochlear synapses that we observed in vitro after synaptic loss due to kainic acid-induced glutamate toxicity and were elicited by administration of TrkB agonists, amitriptyline, and 7,8-dihydroxyflavone, directly into the cochlea via the posterior semicircular canal 48 hours after exposure to noise. Synaptic counts at the inner hair cell and wave 1 amplitudes in the auditory brainstem response (ABR) were partially restored 2 weeks after drug treatment. Effects of amitriptyline on wave 1 amplitude and afferent auditory synapse numbers in noise-exposed ears after systemic (as opposed to local) delivery were profound and long-lasting; synapses in the treated animals remained intact 1 year after the treatment. However, the effect of systemically delivered amitriptyline on synaptic rescue was dependent on dose and the time window of administration: it was only effective when given before noise exposure at the highest injected dose. The long-lasting effect and the efficacy of postexposure treatment indicate a potential broad application for the treatment of synaptopathy, which often goes undetected until well after the original damaging exposures.
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Affiliation(s)
- Katharine A Fernandez
- Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts, USA.,Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts, USA
| | - Takahisa Watabe
- Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts, USA.,Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts, USA
| | - Mingjie Tong
- Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts, USA.,Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts, USA
| | - Xiankai Meng
- Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts, USA.,Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts, USA
| | - Kohsuke Tani
- Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts, USA.,Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts, USA
| | - Sharon G Kujawa
- Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts, USA.,Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, Massachusetts, USA
| | - Albert Sb Edge
- Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts, USA.,Eaton-Peabody Laboratories, Massachusetts Eye and Ear, Boston, Massachusetts, USA.,Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, Massachusetts, USA.,Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
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13
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BDNF Outperforms TrkB Agonist 7,8,3'-THF in Preserving the Auditory Nerve in Deafened Guinea Pigs. Brain Sci 2020; 10:brainsci10110787. [PMID: 33126525 PMCID: PMC7692073 DOI: 10.3390/brainsci10110787] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/23/2020] [Accepted: 10/27/2020] [Indexed: 02/06/2023] Open
Abstract
In deaf subjects using a cochlear implant (CI) for hearing restoration, the auditory nerve is subject to degeneration, which may negatively impact CI effectiveness. This nerve degeneration can be reduced by neurotrophic treatment. Here, we compare the preservative effects of the naturally occurring tyrosine receptor kinase B (TrkB) agonist brain-derived neurotrophic factor (BDNF) and the small-molecule TrkB agonist 7,8,3′-trihydroxyflavone (THF) on the auditory nerve in deafened guinea pigs. THF may be more effective than BDNF throughout the cochlea because of better pharmacokinetic properties. The neurotrophic compounds were delivered by placement of a gelatin sponge on the perforated round window membrane. To complement the histology of spiral ganglion cells (SGCs), electrically evoked compound action potential (eCAP) recordings were performed four weeks after treatment initiation. We analyzed the eCAP inter-phase gap (IPG) effect and measures derived from pulse-train evoked eCAPs, both indicative of SGC healthiness. BDNF but not THF yielded a significantly higher survival of SGCs in the basal cochlear turn than untreated controls. Regarding IPG effect and pulse-train responses, the BDNF-treated animals exhibited more normal responses than both untreated and THF-treated animals. We have thus confirmed the protective effect of BDNF, but we have not confirmed previously reported protective effects of THF with our clinically applicable delivery method.
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14
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Does Calcium Dobesilate Have Therapeutic Effect on Gentamicin-induced Cochlear Nerve Ototoxicity? An Experimental Study. Otol Neurotol 2020; 41:e1185-e1192. [PMID: 32976341 DOI: 10.1097/mao.0000000000002820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
HYPOTHESIS The ototoxic effects of aminoglycosides are well known. Gentamicin carries a substantial risk of hearing loss. Gentamicin is widely used to combat life-threatening infections, despite its ototoxic effects. Calcium dobesilate is a pharmacologically active agent used to treat many disorders due to its vasoprotective and antioxidant effects. We investigated the therapeutic role of calcium dobesilate against gentamicin-induced cochlear nerve ototoxicity in an animal model. METHODS Thirty-two Sprague Dawley rats were divided into four groups: Gentamicin, Gentamicin + Calcium Dobesilate, Calcium Dobesilate, and Control. Preoperative and postoperative hearing thresholds were determined using auditory brainstem response thresholds with click and 16-kHz tone-burst stimuli. Histological analysis of the tympanic bulla specimens was performed under light and transmission electron microscopy. The histological findings were subjected to semiquantitative grading, of which the results were compared between the groups. RESULTS Gentamicin + Calcium Dobesilate group had, on average, 27 dB better click-evoked hearing than Gentamicin group (p < 0.01), whereas the difference was not significant with 16-kHz tone-burst stimuli (p > 0.01). Histologically examining the Control and Calcium Dobesilate groups revealed normal ultrastructural appearances. The Gentamicin group showed the most severe histological alterations including myelin destruction, total axonal degeneration, and edema. The histological evidence of damage was significantly reduced in the Gentamicin + Calcium Dobesilate group compared with the Gentamicin group. CONCLUSION Adding oral calcium dobesilate to systemic gentamicin was demonstrated to exert beneficial effects on click-evoked hearing thresholds, as supported by the histological findings.
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15
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Emili M, Guidi S, Uguagliati B, Giacomini A, Bartesaghi R, Stagni F. Treatment with the flavonoid 7,8-Dihydroxyflavone: a promising strategy for a constellation of body and brain disorders. Crit Rev Food Sci Nutr 2020; 62:13-50. [DOI: 10.1080/10408398.2020.1810625] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Marco Emili
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Sandra Guidi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Beatrice Uguagliati
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Andrea Giacomini
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Renata Bartesaghi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy
| | - Fiorenza Stagni
- Department for Life Quality Studies, University of Bologna, Rimini, Italy
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16
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Frick C, Fink S, Schmidbauer D, Rousset F, Eickhoff H, Tropitzsch A, Kramer B, Senn P, Glueckert R, Rask-Andersen H, Wiesmüller KH, Löwenheim H, Müller M. Age-Dependency of Neurite Outgrowth in Postnatal Mouse Cochlear Spiral Ganglion Explants. Brain Sci 2020; 10:E580. [PMID: 32839381 PMCID: PMC7564056 DOI: 10.3390/brainsci10090580] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND The spatial gap between cochlear implants (CIs) and the auditory nerve limits frequency selectivity as large populations of spiral ganglion neurons (SGNs) are electrically stimulated synchronously. To improve CI performance, a possible strategy is to promote neurite outgrowth toward the CI, thereby allowing a discrete stimulation of small SGN subpopulations. Brain-derived neurotrophic factor (BDNF) is effective to stimulate neurite outgrowth from SGNs. METHOD TrkB (tropomyosin receptor kinase B) agonists, BDNF, and five known small-molecule BDNF mimetics were tested for their efficacy in stimulating neurite outgrowth in postnatal SGN explants. To modulate Trk receptor-mediated effects, TrkB and TrkC ligands were scavenged by an excess of recombinant receptor proteins. The pan-Trk inhibitor K252a was used to block Trk receptor actions. RESULTS THF (7,8,3'-trihydroxyflavone) partly reproduced the BDNF effect in postnatal day 7 (P7) mouse cochlear spiral ganglion explants (SGEs), but failed to show effectiveness in P4 SGEs. During the same postnatal period, spontaneous and BDNF-stimulated neurite outgrowth increased. The increased neurite outgrowth in P7 SGEs was not caused by the TrkB/TrkC ligands, BDNF and neurotrophin-3 (NT-3). CONCLUSIONS The age-dependency of induction of neurite outgrowth in SGEs was very likely dependent on presently unidentified factors and/or molecular mechanisms which may also be decisive for the age-dependent efficacy of the small-molecule TrkB receptor agonist THF.
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Affiliation(s)
- Claudia Frick
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
- Department of Microbiome Science, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Stefan Fink
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
| | - Dominik Schmidbauer
- Inner Ear Laboratory Innsbruck, Medical University Innsbruck, 6020 Innsbruck, Austria; (D.S.); (R.G.)
| | - Francis Rousset
- The Inner Ear & Olfaction Lab, Department of Clinical Neurosciences, Faculty of Medicine, University of Geneva, 1206 Geneva, Switzerland; (F.R.); (P.S.)
| | - Holger Eickhoff
- EMC Microcollections GmbH, 72070 Tübingen, Germany; (H.E.); (K.-H.W.)
| | - Anke Tropitzsch
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
| | - Benedikt Kramer
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
- Department of Otolaryngology, Head and Neck Surgery, University Hospital Mannheim, 68167 Mannheim, Germany
| | - Pascal Senn
- The Inner Ear & Olfaction Lab, Department of Clinical Neurosciences, Faculty of Medicine, University of Geneva, 1206 Geneva, Switzerland; (F.R.); (P.S.)
| | - Rudolf Glueckert
- Inner Ear Laboratory Innsbruck, Medical University Innsbruck, 6020 Innsbruck, Austria; (D.S.); (R.G.)
- Tirol Kliniken Innsbruck, University Clinic of Otolaryngology, 6020 Innsbruck, Austria
| | - Helge Rask-Andersen
- Department of Surgical Sciences, Otorhinolaryngology and Head and Neck Surgery, University of Uppsala, 751 85 Uppsala, Sweden;
| | | | - Hubert Löwenheim
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
| | - Marcus Müller
- Department of Otolaryngology, Head and Neck Surgery, Tübingen Hearing Research Centre, University of Tübingen Medical Center, 72076 Tübingen, Germany; (C.F.); (A.T.); (B.K.); (H.L.); (M.M.)
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17
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Szobota S, Mathur PD, Siegel S, Black K, Saragovi HU, Foster AC. BDNF, NT-3 and Trk receptor agonist monoclonal antibodies promote neuron survival, neurite extension, and synapse restoration in rat cochlea ex vivo models relevant for hidden hearing loss. PLoS One 2019; 14:e0224022. [PMID: 31671109 PMCID: PMC6822712 DOI: 10.1371/journal.pone.0224022] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 10/03/2019] [Indexed: 12/21/2022] Open
Abstract
Neurotrophins and their mimetics are potential treatments for hearing disorders because of their trophic effects on spiral ganglion neurons (SGNs) whose connections to hair cells may be compromised in many forms of hearing loss. Studies in noise or ototoxin-exposed animals have shown that local delivery of NT-3 or BDNF has beneficial effects on SGNs and hearing. We evaluated several TrkB or TrkC monoclonal antibody agonists and small molecules, along with BDNF and NT-3, in rat cochlea ex vivo models. The TrkB agonists BDNF and a monoclonal antibody, M3, had the greatest effects on SGN survival, neurite outgrowth and branching. In organotypic cochlear explants, BDNF and M3 enhanced synapse formation between SGNs and inner hair cells and restored these connections after excitotoxin-induced synaptopathy. Loss of these synapses has recently been implicated in hidden hearing loss, a condition characterized by difficulty hearing speech in the presence of background noise. The unique profile of M3 revealed here warrants further investigation, and the broad activity profile of BDNF observed underpins its continued development as a hearing loss therapeutic.
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Affiliation(s)
- Stephanie Szobota
- Otonomy, Inc., San Diego, California, United States of America
- * E-mail:
| | | | - Sairey Siegel
- Otonomy, Inc., San Diego, California, United States of America
| | | | - H. Uri Saragovi
- Lady Davis Institute-Jewish General Hospital, McGill University, Montreal, Quebec, Canada
| | - Alan C. Foster
- Otonomy, Inc., San Diego, California, United States of America
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18
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Guo S, Xu N, Chen P, Liu Y, Qi X, Liu S, Li C, Tang J. Rapamycin Protects Spiral Ganglion Neurons from Gentamicin-Induced Degeneration In Vitro. J Assoc Res Otolaryngol 2019; 20:475-487. [PMID: 31236744 DOI: 10.1007/s10162-019-00717-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2018] [Accepted: 03/12/2019] [Indexed: 02/06/2023] Open
Abstract
Gentamicin, one of the most widely used aminoglycoside antibiotics, is known to have toxic effects on the inner ear. Taken up by cochlear hair cells and spiral ganglion neurons (SGNs), gentamicin induces the accumulation of reactive oxygen species (ROS) and initiates apoptosis or programmed cell death, resulting in a permanent and irreversible hearing loss. Since the survival of SGNs is specially required for cochlear implant, new procedures that prevent SGN cell loss are crucial to the success of cochlear implantation. ROS modulates the activity of the mammalian target of rapamycin (mTOR) signaling pathway, which mediates apoptosis or autophagy in cells of different organs. However, whether mTOR signaling plays an essential role in the inner ear and whether it is involved in the ototoxic side effects of gentamicin remain unclear. In the present study, we found that gentamicin induced apoptosis and cell loss of SGNs in vivo and significantly decreased the density of SGN and outgrowth of neurites in cultured SGN explants. The phosphorylation levels of ribosomal S6 kinase and elongation factor 4E binding protein 1, two critical kinases in the mTOR complex 1 (mTORC1) signaling pathway, were modulated by gentamicin application in the cochlea. Meanwhile, rapamycin, a specific inhibitor of mTORC1, was co-applied with gentamicin to verify the role of mTOR signaling. We observed that the density of SGN and outgrowth of neurites were significantly increased by rapamycin treatment. Our finding suggests that mTORC1 is hyperactivated in the gentamicin-induced degeneration of SGNs, and rapamycin promoted SGN survival and outgrowth of neurites.
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Affiliation(s)
- Shasha Guo
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Nana Xu
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Peng Chen
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Ying Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xiaofei Qi
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Sheng Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Cuixian Li
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China. .,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China. .,Institute of Mental Health, Southern Medical University, Guangzhou, China.
| | - Jie Tang
- Department of Physiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China. .,Key Laboratory of Mental Health of the Ministry of Education, Southern Medical University, Guangzhou, China. .,Institute of Mental Health, Southern Medical University, Guangzhou, China.
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19
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Advances in cochlear implantation for hereditary deafness caused by common mutations in deafness genes. JOURNAL OF BIO-X RESEARCH 2019. [DOI: 10.1097/jbr.0000000000000037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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20
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Liu W, Wang X, Wang M, Wang H. Protection of Spiral Ganglion Neurons and Prevention of Auditory Neuropathy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1130:93-107. [DOI: 10.1007/978-981-13-6123-4_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
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21
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Kempfle JS, Nguyen K, Hamadani C, Koen N, Edge AS, Kashemirov BA, Jung DH, McKenna CE. Bisphosphonate-Linked TrkB Agonist: Cochlea-Targeted Delivery of a Neurotrophic Agent as a Strategy for the Treatment of Hearing Loss. Bioconjug Chem 2018; 29:1240-1250. [PMID: 29485861 DOI: 10.1021/acs.bioconjchem.8b00022] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Hearing loss affects more than two-thirds of the elderly population, and more than 17% of all adults in the U.S. Sensorineural hearing loss related to noise exposure or aging is associated with loss of inner ear sensory hair cells (HCs), cochlear spiral ganglion neurons (SGNs), and ribbon synapses between HCs and SGNs, stimulating intense interest in therapies to regenerate synaptic function. 7,8-Dihydroxyflavone (DHF) is a selective and potent agonist of tropomyosin receptor kinase B (TrkB) and protects the neuron from apoptosis. Despite evidence that TrkB agonists can promote survival of SGNs, local delivery of drugs such as DHF to the inner ear remains a challenge. We previously demonstrated in an animal model that a fluorescently labeled bisphosphonate, 6-FAM-Zol, administered to the round window membrane penetrated the membrane and diffused throughout the cochlea. Given their affinity for bone mineral, including cochlear bone, bisphosphonates offer an intriguing modality for targeted delivery of neurotrophic agents to the SGNs to promote survival, neurite outgrowth, and, potentially, regeneration of synapses between HCs and SGNs. The design and synthesis of a bisphosphonate conjugate of DHF (Ris-DHF) is presented, with a preliminary evaluation of its neurotrophic activity. Ris-DHF increases neurite outgrowth in vitro, maintains this ability after binding to hydroxyapatite, and regenerates synapses in kainic acid-damaged cochlear organ of Corti explants dissected in vitro with attached SGNs. The results suggest that bisphosphonate-TrkB agonist conjugates have promise as a novel approach to targeted delivery of drugs to treat sensorineural hearing loss.
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Affiliation(s)
- Judith S Kempfle
- Department of Otolaryngology and The Eaton-Peabody Laboratories , Massachusetts Eye and Ear Infirmary , Boston , Massachusetts 02114 , United States.,Department of Otology and Laryngology , Harvard Medical School , Boston , Massachusetts 02114 , United States.,Department of Otolaryngology , University of Tübingen Medical Center , Tübingen 72076 , Germany
| | - Kim Nguyen
- Department of Chemistry , University of Southern California , Los Angeles , California 90089-0744 , United States
| | - Christine Hamadani
- Department of Otolaryngology and The Eaton-Peabody Laboratories , Massachusetts Eye and Ear Infirmary , Boston , Massachusetts 02114 , United States.,Department of Otology and Laryngology , Harvard Medical School , Boston , Massachusetts 02114 , United States
| | - Nicholas Koen
- Department of Otolaryngology and The Eaton-Peabody Laboratories , Massachusetts Eye and Ear Infirmary , Boston , Massachusetts 02114 , United States.,Department of Otology and Laryngology , Harvard Medical School , Boston , Massachusetts 02114 , United States
| | - Albert S Edge
- Department of Otolaryngology and The Eaton-Peabody Laboratories , Massachusetts Eye and Ear Infirmary , Boston , Massachusetts 02114 , United States.,Department of Otology and Laryngology , Harvard Medical School , Boston , Massachusetts 02114 , United States
| | - Boris A Kashemirov
- Department of Chemistry , University of Southern California , Los Angeles , California 90089-0744 , United States
| | - David H Jung
- Department of Otolaryngology and The Eaton-Peabody Laboratories , Massachusetts Eye and Ear Infirmary , Boston , Massachusetts 02114 , United States.,Department of Otology and Laryngology , Harvard Medical School , Boston , Massachusetts 02114 , United States
| | - Charles E McKenna
- Department of Chemistry , University of Southern California , Los Angeles , California 90089-0744 , United States
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22
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Basinou V, Park JS, Cederroth CR, Canlon B. Circadian regulation of auditory function. Hear Res 2017; 347:47-55. [PMID: 27665709 PMCID: PMC5364078 DOI: 10.1016/j.heares.2016.08.018] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 08/25/2016] [Indexed: 12/11/2022]
Abstract
The circadian system integrates environmental cues to regulate physiological functions in a temporal fashion. The suprachiasmatic nucleus, located in the hypothalamus, is the master clock that synchronizes central and peripheral organ clocks to orchestrate physiological functions. Recently, molecular clock machinery has been identified in the cochlea unravelling the potential involvement in the circadian regulation of auditory functions. Here, we present background information on the circadian system and review the recent findings that introduce circadian rhythms to the auditory field. Understanding the mechanisms by which circadian rhythms regulate auditory function will provide fundamental knowledge on the signalling networks that control vulnerability and resilience to auditory insults.
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Affiliation(s)
- Vasiliki Basinou
- Department of Physiology and Pharmacology, Laboratory of Experimental Audiology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Jung-Sub Park
- Department of Physiology and Pharmacology, Laboratory of Experimental Audiology, Karolinska Institutet, 171 77 Stockholm, Sweden; Department of Otolaryngology, Ajou University School of Medicine, 164, Worldcup-ro, Yeongtong-gu, Suwon, 16499, South Korea
| | - Christopher R Cederroth
- Department of Physiology and Pharmacology, Laboratory of Experimental Audiology, Karolinska Institutet, 171 77 Stockholm, Sweden
| | - Barbara Canlon
- Department of Physiology and Pharmacology, Laboratory of Experimental Audiology, Karolinska Institutet, 171 77 Stockholm, Sweden.
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23
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Shi H, Luo X. 7, 8, 3'-Trihydroxyflavone Promotes Neurite Outgrowth and Protects Against Bupivacaine-Induced Neurotoxicity in Mouse Dorsal Root Ganglion Neurons. Med Sci Monit 2016; 22:2301-8. [PMID: 27371503 PMCID: PMC4941892 DOI: 10.12659/msm.896961] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Background 7, 8, 3′-trihydroxyflavone (THF) is a novel pro-neuronal small molecule that acts as a TrkB agonist. In this study, we examined the effect of THF on promoting neuronal growth and protecting anesthetics-induced neurotoxicity in dorsal root ganglion (DRG) neurons in vitro. Material/Methods Neonatal mouse DRG neurons were cultured in vitro and treated with various concentrations of THF. The effect of THF on neuronal growth was investigated by neurite outgrowth assay and Western blot. In addition, the protective effects of THF on bupivacaine-induced neurotoxicity were investigated by apoptosis TUNEL assay, neurite outgrowth assay, and Western blot, respectively. Results THF promoted neurite outgrowth of DRG neurons in dose-dependent manner, with an EC50 concentration of 67.4 nM. Western blot analysis showed THF activated TrkB signaling pathway by inducing TrkB phosphorylation. THF also rescued bupivacaine-induced neurotoxicity by reducing apoptosis and protecting neurite retraction in DRG neurons. Furthermore, the protection of THF in bupivacaine-injured neurotoxicity was directly associated with TrkB phosphorylation in a concentration-dependent manner in DRG neurons. Conclusions THF has pro-neuronal effect on DRG neurons by promoting neurite growth and protecting against bupivacaine-induced neurotoxicity, likely through TrkB activation.
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Affiliation(s)
- Haohong Shi
- Department of Anesthesia, Children's Hospital, Fudan University, Shanghai, China (mainland)
| | - Xingjing Luo
- Department of Anesthesia, Children's Hospital, Fudan University, Shanghai, China (mainland)
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Lysine-specific demethylase 1 inhibitors protect cochlear spiral ganglion neurons against cisplatin-induced damage. Neuroreport 2016; 26:539-47. [PMID: 26011390 DOI: 10.1097/wnr.0000000000000386] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Cisplatin is a widely used chemotherapeutic drug, but one of its side effects is ototoxicity. Epigenetic-related drugs, such as lysine-specific demethylase 1 (LSD1) inhibitors, have been reported to protect against cisplatin-induced hair cell loss by preventing demethylation of histone H3K4 (H3K4me2). However, the protective effect of LSD1 inhibitors in spiral ganglion neurons (SGNs) remains unclear. To investigate whether LSD1 inhibitors exert similar protective effects on SGNs, we treated mouse cochlear explant cultures with LSD1 inhibitors (2PCPA, S2101, or CBB1007) together with cisplatin. Low concentrations of cisplatin damaged SGNs much more than high concentrations, and blocking the demethylation of H3K4me2 with LSD1 inhibitors prevented the SGNs from injury. Reactive oxygen species are also involved in the injury process, and LSD1 inhibitors protected SGNs by increasing the expression level of the antioxidant gene Slc7a11 and decreasing the level of the pro-oxidant gene lactoperoxidase (Lpo). Our findings show that LSD1 inhibitors prevent cisplatin-induced SGN loss by regulating the demethylation of H3K4 and preventing increases of reactive oxygen species levels, which might provide a potential therapeutic strategy for cisplatin-induced hearing loss.
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Liu C, Chan CB, Ye K. 7,8-dihydroxyflavone, a small molecular TrkB agonist, is useful for treating various BDNF-implicated human disorders. Transl Neurodegener 2016; 5:2. [PMID: 26740873 PMCID: PMC4702337 DOI: 10.1186/s40035-015-0048-7] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 12/29/2015] [Indexed: 12/21/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) regulates a variety of biological processes predominantly via binding to the transmembrane receptor tyrosine kinase TrkB. It is a potential therapeutic target in numerous neurological, mental and metabolic disorders. However, the lack of efficient means to deliver BDNF into the body imposes an insurmountable hurdle to its clinical application. To address this challenge, we initiated a cell-based drug screening to search for small molecules that act as the TrkB agonist. 7,8-Dihydroxyflavone (7,8-DHF) is our first reported small molecular TrkB agonist, which has now been extensively validated in various biochemical and cellular systems. Though binding to the extracellular domain of TrkB, 7,8-DHF triggers TrkB dimerization to induce the downstream signaling. Notably, 7,8-DHF is orally bioactive that can penetrate the brain blood barrier (BBB) to exert its neurotrophic activities in the central nervous system. Numerous reports suggest 7,8-DHF processes promising therapeutic efficacy in various animal disease models that are related to deficient BDNF signaling. In this review, we summarize our current knowledge on the binding activity and specificity, structure-activity relationship, pharmacokinetic and metabolism, and the pre-clinical efficacy of 7,8-DHF against some human diseases.
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Affiliation(s)
- Chaoyang Liu
- School of Information and Safety Engineering, Zhongnan University of Economics and Law, Wuhan, 430073 P.R. China
| | - Chi Bun Chan
- Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Blvd., Oklahoma City, OK 73104 USA
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322 USA
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Moosavi F, Hosseini R, Saso L, Firuzi O. Modulation of neurotrophic signaling pathways by polyphenols. DRUG DESIGN DEVELOPMENT AND THERAPY 2015; 10:23-42. [PMID: 26730179 PMCID: PMC4694682 DOI: 10.2147/dddt.s96936] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Polyphenols are an important class of phytochemicals, and several lines of evidence have demonstrated their beneficial effects in the context of a number of pathologies including neurodegenerative disorders such as Alzheimer’s and Parkinson’s disease. In this report, we review the studies on the effects of polyphenols on neuronal survival, growth, proliferation and differentiation, and the signaling pathways involved in these neurotrophic actions. Several polyphenols including flavonoids such as baicalein, daidzein, luteolin, and nobiletin as well as nonflavonoid polyphenols such as auraptene, carnosic acid, curcuminoids, and hydroxycinnamic acid derivatives including caffeic acid phentyl ester enhance neuronal survival and promote neurite outgrowth in vitro, a hallmark of neuronal differentiation. Assessment of underlying mechanisms, especially in PC12 neuronal-like cells, reveals that direct agonistic effect on tropomyosin receptor kinase (Trk) receptors, the main receptors of neurotrophic factors including nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) explains the action of few polyphenols such as 7,8-dihydroxyflavone. However, several other polyphenolic compounds activate extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K)/Akt pathways. Increased expression of neurotrophic factors in vitro and in vivo is the mechanism of neurotrophic action of flavonoids such as scutellarin, daidzein, genistein, and fisetin, while compounds like apigenin and ferulic acid increase cyclic adenosine monophosphate response element-binding protein (CREB) phosphorylation. Finally, the antioxidant activity of polyphenols reflected in the activation of Nrf2 pathway and the consequent upregulation of detoxification enzymes such as heme oxygenase-1 as well as the contribution of these effects to the neurotrophic activity have also been discussed. In conclusion, a better understanding of the neurotrophic effects of polyphenols and the concomitant modulations of signaling pathways is useful for designing more effective agents for management of neurodegenerative diseases.
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Affiliation(s)
- Fatemeh Moosavi
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmacology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Razieh Hosseini
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmacology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Luciano Saso
- Department of Physiology and Pharmacology "Vittorio Erspamer", Sapienza University of Rome, Rome, Italy
| | - Omidreza Firuzi
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Cochlear afferent innervation development. Hear Res 2015; 330:157-69. [DOI: 10.1016/j.heares.2015.07.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 06/02/2015] [Accepted: 07/21/2015] [Indexed: 01/11/2023]
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Homsy A, Laux E, Brossard J, Whitlow HJ, Roccio M, Hahnewald S, Senn P, Mistrík P, Hessler R, Melchionna T, Frick C, Löwenheim H, Müller M, Wank U, Wiesmüller KH, Keppner H. Fine control of drug delivery for cochlear implant applications. HEARING BALANCE AND COMMUNICATION 2015. [DOI: 10.3109/21695717.2015.1048082] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Chan CB, Tse MCL, Liu X, Zhang S, Schmidt R, Otten R, Liu L, Ye K. Activation of muscular TrkB by its small molecular agonist 7,8-dihydroxyflavone sex-dependently regulates energy metabolism in diet-induced obese mice. ACTA ACUST UNITED AC 2015; 22:355-68. [PMID: 25754472 DOI: 10.1016/j.chembiol.2015.02.003] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 01/30/2015] [Accepted: 02/05/2015] [Indexed: 12/22/2022]
Abstract
Chronic activation of brain-derived neurotrophic factor (BDNF) receptor TrkB is a potential method to prevent development of obesity, but the short half-life and nonbioavailable nature of BDNF hampers validation of the hypothesis. We report here that activation of muscular TrkB by the BDNF mimetic, 7,8-dihydroxyflavone (7,8-DHF), is sufficient to protect the development of diet-induced obesity in female mice. Using in vitro and in vivo models, we found that 7,8-DHF treatment enhanced the expression of uncoupling protein 1 (UCP1) and AMP-activated protein kinase (AMPK) activity in skeletal muscle, which resulted in increased systemic energy expenditure, reduced adiposity, and improved insulin sensitivity in female mice fed a high-fat diet. This antiobesity activity of 7,8-DHF is muscular TrkB-dependent as 7,8-DHF cannot mitigate diet-induced obesity in female muscle-specific TrkB knockout mice. Hence, our data reveal that chronic activation of muscular TrkB is useful in alleviating obesity and its complications.
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Affiliation(s)
- Chi Bun Chan
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA; Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA
| | - Margaret Chui Ling Tse
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA; Department of Physiology, University of Oklahoma Health Sciences Center, 940 Stanton L. Young Boulevard, Oklahoma City, OK 73104, USA
| | - Xia Liu
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Shuai Zhang
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Robin Schmidt
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Reed Otten
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | - Liegang Liu
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science & Technology, 13 Hangkong Road, Wuhan, 430030, P.R. China
| | - Keqiang Ye
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA.
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30
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Pinyon JL, Tadros SF, Froud KE, Y Wong AC, Tompson IT, Crawford EN, Ko M, Morris R, Klugmann M, Housley GD. Close-field electroporation gene delivery using the cochlear implant electrode array enhances the bionic ear. Sci Transl Med 2015; 6:233ra54. [PMID: 24760189 DOI: 10.1126/scitranslmed.3008177] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The cochlear implant is the most successful bionic prosthesis and has transformed the lives of people with profound hearing loss. However, the performance of the "bionic ear" is still largely constrained by the neural interface itself. Current spread inherent to broad monopolar stimulation of the spiral ganglion neuron somata obviates the intrinsic tonotopic mapping of the cochlear nerve. We show in the guinea pig that neurotrophin gene therapy integrated into the cochlear implant improves its performance by stimulating spiral ganglion neurite regeneration. We used the cochlear implant electrode array for novel "close-field" electroporation to transduce mesenchymal cells lining the cochlear perilymphatic canals with a naked complementary DNA gene construct driving expression of brain-derived neurotrophic factor (BDNF) and a green fluorescent protein (GFP) reporter. The focusing of electric fields by particular cochlear implant electrode configurations led to surprisingly efficient gene delivery to adjacent mesenchymal cells. The resulting BDNF expression stimulated regeneration of spiral ganglion neurites, which had atrophied 2 weeks after ototoxic treatment, in a bilateral sensorineural deafness model. In this model, delivery of a control GFP-only vector failed to restore neuron structure, with atrophied neurons indistinguishable from unimplanted cochleae. With BDNF therapy, the regenerated spiral ganglion neurites extended close to the cochlear implant electrodes, with localized ectopic branching. This neural remodeling enabled bipolar stimulation via the cochlear implant array, with low stimulus thresholds and expanded dynamic range of the cochlear nerve, determined via electrically evoked auditory brainstem responses. This development may broadly improve neural interfaces and extend molecular medicine applications.
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Affiliation(s)
- Jeremy L Pinyon
- Translational Neuroscience Facility and Department of Physiology, School of Medical Sciences, University of New South Wales, UNSW Australia, Sydney, New South Wales 2052, Australia
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Liu X, Obianyo O, Chan CB, Huang J, Xue S, Yang JJ, Zeng F, Goodman M, Ye K. Biochemical and biophysical investigation of the brain-derived neurotrophic factor mimetic 7,8-dihydroxyflavone in the binding and activation of the TrkB receptor. J Biol Chem 2014; 289:27571-84. [PMID: 25143381 DOI: 10.1074/jbc.m114.562561] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
7,8-dihydroxyflavone (7,8-DHF), a newly identified small molecular TrkB receptor agonist, rapidly activates TrkB in both primary neurons and the rodent brain and mimics the physiological functions of the cognate ligand BDNF. Accumulating evidence supports that 7,8-DHF exerts neurotrophic effects in a TrkB-dependent manner. Nonetheless, the differences between 7,8-DHF and BDNF in activating TrkB remain incompletely understood. Here we show that 7,8-DHF and BDNF exhibit different TrkB activation kinetics in which TrkB maturation may be implicated. Employing two independent biophysical approaches, we confirm that 7,8-DHF interacts robustly with the TrkB extracellular domain, with a Kd of ∼10 nm. Although BDNF transiently activates TrkB, leading to receptor internalization and ubiquitination/degradation, in contrast, 7,8-DHF-triggered TrkB phosphorylation lasts for hours, and the internalized receptors are not degraded. Notably, primary neuronal maturation may be required for 7,8-DHF but not for BDNF to elicit the full spectrum of TrkB signaling cascades. Hence, 7,8-DHF interacts robustly with the TrkB receptor, and its agonistic effect may be mediated by neuronal development and maturation.
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Affiliation(s)
- Xia Liu
- From the Departments of Pathology and Laboratory Medicine and
| | | | - Chi Bun Chan
- From the Departments of Pathology and Laboratory Medicine and
| | - Junjian Huang
- From the Departments of Pathology and Laboratory Medicine and
| | - Shenghui Xue
- the Departments of Chemistry and Biology, Center for Diagnostics and Therapeutics (CDT), Georgia State University, Atlanta, Georgia 30303
| | - Jenny J Yang
- the Departments of Chemistry and Biology, Center for Diagnostics and Therapeutics (CDT), Georgia State University, Atlanta, Georgia 30303
| | - Fanxing Zeng
- Radiology and Imaging Sciences, Psychiatry, and Hematology and Oncology, Center for Systems Imaging, Wesley Woods Health Centers, Emory University School of Medicine, Atlanta, Georgia 30322 and
| | - Mark Goodman
- Radiology and Imaging Sciences, Psychiatry, and Hematology and Oncology, Center for Systems Imaging, Wesley Woods Health Centers, Emory University School of Medicine, Atlanta, Georgia 30322 and
| | - Keqiang Ye
- From the Departments of Pathology and Laboratory Medicine and
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32
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Huai R, Han X, Wang B, Li C, Niu Y, Li R, Qu Z. Vasorelaxing and antihypertensive effects of 7,8-dihydroxyflavone. Am J Hypertens 2014; 27:750-60. [PMID: 24317273 DOI: 10.1093/ajh/hpt220] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Although 7,8-dihydroxyflavone (7,8-DHF) has been demonstrated to be potently neuroprotective, its effect on vascular function remains unknown. METHODS The effect of 7,8-DHF on phenylephrine (PE)-induced preconstriction was examined with aortic rings isolated from normal rats. Its effective mechanisms were studied with blockers, Western blotting, and primarily cultured vascular smooth myocytes. The blood pressure (BP) of rats was measured with a tail cuff method. RESULTS 7,8-DHF dose-dependently dilated the PE-preconstricted, endothelia-intact aortic rings with concentration for 50% of maximal effect (EC50) of approximately 24 µM. Both Nω-nitro-L-arginine methyl ester hydrochloride, a nitric oxide synthase inhibitor, and 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one, a soluble guanylyl cyclase blocker, significantly reduced the vasorelaxing effect of 7,8-DHF. Western blotting showed that 7,8-DHF increased the aortic endothelial nitric oxide synthase protein expression and phosphorylation. With endothelia removed, 7,8-DHF also dilated the PE-preconstricted rings but with EC50 of approximately 104 µM. Ca(2+) imaging experiments detected that 7,8-DHF probably blocked both intracellular Ca(2+) release and extracellular Ca(2+) influx. Therefore, the mechanisms of 7,8-DHF dilating effect might be stimulating the nitric oxide/cGMP production and blocking the Ca(2+) signaling pathway instead of tropomyosin receptor kinase B receptors because ANA-12, its specific antagonist, did not show any effect against 7,8-DHF. When administered intravenously, 7,8-DHF significantly reduced the BP of the spontaneously hypertensive rats. However, when used orally, there was only a slight but significant reduction in the diastolic pressure. CONCLUSIONS The results suggest that neuro-protective 7,8-DHF is also a vasorelaxing and antihypertensive substance in rats.
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MESH Headings
- Administration, Oral
- Animals
- Antihypertensive Agents/administration & dosage
- Antihypertensive Agents/pharmacology
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/enzymology
- Calcium Signaling/drug effects
- Cells, Cultured
- Cyclic GMP/metabolism
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/enzymology
- Endothelium, Vascular/physiopathology
- Flavones/administration & dosage
- Flavones/pharmacology
- Hypertension/drug therapy
- Hypertension/enzymology
- Hypertension/physiopathology
- Injections, Intravenous
- Nitric Oxide/metabolism
- Nitric Oxide Synthase Type III/metabolism
- Phosphorylation
- Rats, Inbred SHR
- Vasodilation/drug effects
- Vasodilator Agents/administration & dosage
- Vasodilator Agents/pharmacology
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Affiliation(s)
- Ruituo Huai
- Department of Physiology, Qingdao University Medical College, Qingdao, China
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TrkB-mediated protection against circadian sensitivity to noise trauma in the murine cochlea. Curr Biol 2014; 24:658-63. [PMID: 24583017 DOI: 10.1016/j.cub.2014.01.047] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Revised: 12/20/2013] [Accepted: 01/21/2014] [Indexed: 12/17/2022]
Abstract
Noise-induced hearing loss (NIHL) is a debilitating sensory impairment affecting 10%-15% of the population, caused primarily through damage to the sensory hair cells or to the auditory neurons. Once lost, these never regenerate [1], and no effective drugs are available [2, 3]. Emerging evidence points toward an important contribution of synaptic ribbons in the long-term coupling of the inner hair cell and afferent neuron synapse to maintain hearing [4]. Here we show in nocturnal mice that night noise overexposure triggers permanent hearing loss, whereas mice overexposed during the day recover to normal auditory thresholds. In view of this time-dependent sensitivity, we identified a self-sustained circadian rhythm in the isolated cochlea, as evidenced by circadian expression of clock genes and ample PERIOD2::LUCIFERASE oscillations, originating mainly from the primary auditory neurons and hair cells. The transcripts of the otoprotecting brain-derived neurotrophic factor (BDNF) showed higher levels in response to day noise versus night noise, suggesting that BDNF-mediated signaling regulates noise sensitivity throughout the day. Administration of a selective BDNF receptor, tropomyosin-related kinase type B (TrkB), in the night protected the inner hair cell's synaptic ribbons and subsequent full recovery of hearing thresholds after night noise overexposure. The TrkB agonist shifted the phase and boosted the amplitude of circadian rhythms in the isolated cochlea. These findings highlight the coupling of circadian rhythmicity and the TrkB receptor for the successful prevention and treatment of NIHL.
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Takada Y, Beyer LA, Swiderski DL, O'Neal AL, Prieskorn DM, Shivatzki S, Avraham KB, Raphael Y. Connexin 26 null mice exhibit spiral ganglion degeneration that can be blocked by BDNF gene therapy. Hear Res 2013; 309:124-35. [PMID: 24333301 DOI: 10.1016/j.heares.2013.11.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2013] [Revised: 11/16/2013] [Accepted: 11/19/2013] [Indexed: 01/11/2023]
Abstract
Mutations in the connexin 26 gene (GJB2) are the most common genetic cause of deafness, leading to congenital bilateral non-syndromic sensorineural hearing loss. Here we report the generation of a mouse model for a connexin 26 (Cx26) mutation, in which cre-Sox10 drives excision of the Cx26 gene from non-sensory cells flanking the auditory epithelium. We determined that these conditional knockout mice, designated Gjb2-CKO, have a severe hearing loss. Immunocytochemistry of the auditory epithelium confirmed absence of Cx26 in the non-sensory cells. Histology of the organ of Corti and the spiral ganglion neurons (SGNs) performed at ages 1, 3, or 6 months revealed that in Gjb2-CKO mice, the organ of Corti began to degenerate in the basal cochlear turn at an early stage, and the degeneration rapidly spread to the apex. In addition, the density of SGNs in Rosenthal's canal decreased rapidly along a gradient from the base of the cochlea to the apex, where some SGNs survived until at least 6 months of age. Surviving neurons often clustered together and formed clumps of cells in the canal. We then assessed the influence of brain derived neurotrophic factor (BDNF) gene therapy on the SGNs of Gjb2-CKO mice by inoculating Adenovirus with the BDNF gene insert (Ad.BDNF) into the base of the cochlea via the scala tympani or scala media. We determined that over-expression of BDNF beginning around 1 month of age resulted in a significant rescue of neurons in Rosenthal's canal of the cochlear basal turn but not in the middle or apical portions. This data may be used to design therapies for enhancing the SGN physiological status in all GJB2 patients and especially in a sub-group of GJB2 patients where the hearing loss progresses due to ongoing degeneration of the auditory nerve, thereby improving the outcome of cochlear implant therapy in these ears.
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Affiliation(s)
- Yohei Takada
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA; Department of Otolaryngology, Kansai Medical University, 2-3-1, Shinmachi, Hirakata, Osaka 573-1191, Japan
| | - Lisa A Beyer
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA
| | - Donald L Swiderski
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA
| | - Aubrey L O'Neal
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA
| | - Diane M Prieskorn
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA
| | - Shaked Shivatzki
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 69978, Israel
| | - Yehoash Raphael
- Kresge Hearing Research Institute, Department of Otolaryngology - Head and Neck Surgery, University of Michigan, 1150 West. Medical Center Dr., Ann Arbor, MI 48109-5648, USA.
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