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Lu YC, Tsai YH, Chan YH, Hu CJ, Huang CY, Xiao R, Hsu CJ, Vandenberghe LH, Wu CC, Cheng YF. Gene therapy with a synthetic adeno-associated viral vector improves audiovestibular phenotypes in Pjvk-mutant mice. JCI Insight 2022; 7:e152941. [PMID: 36278489 PMCID: PMC9714786 DOI: 10.1172/jci.insight.152941] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 09/02/2022] [Indexed: 11/16/2023] Open
Abstract
Recessive PJVK mutations that cause a deficiency of pejvakin, a protein expressed in both sensory hair cells and first-order neurons of the inner ear, are an important cause of hereditary hearing impairment. Patients with PJVK mutations garner limited benefits from cochlear implantation; thus, alternative biological therapies may be required to address this clinical difficulty. The synthetic adeno-associated viral vector Anc80L65, with its wide tropism and high transduction efficiency in various inner ear cells, may provide a solution. We delivered the PJVK transgene to the inner ear of Pjvk mutant mice using the synthetic Anc80L65 vector. We observed robust exogenous pejvakin expression in the hair cells and neurons of the cochlea and vestibular organs. Subsequent morphologic and audiologic studies demonstrated significant restoration of spiral ganglion neuron density and hair cells in the cochlea, along with partial recovery of sensorineural hearing impairment. In addition, we observed a recovery of vestibular ganglion neurons and balance function to WT levels. Our study demonstrates the utility of Anc80L65-mediated gene delivery in Pjvk mutant mice and provides insights into the potential of gene therapy for PJVK-related inner ear deficits.
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Affiliation(s)
- Ying-Chang Lu
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
| | - Yi-Hsiu Tsai
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Yen-Huei Chan
- Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan
| | - Chin-Ju Hu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
- Program in Speech and Hearing Biosciences and Technology, Harvard Medical School, Boston, Massachusetts, USA
| | - Chun-Ying Huang
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Ru Xiao
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear, Boston, Massachusetts, USA
- Ocular Genomics Institute, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
| | - Chuan-Jen Hsu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Otolaryngology, Taichung Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Taichung, Taiwan
| | - Luk H. Vandenberghe
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear, Boston, Massachusetts, USA
- Ocular Genomics Institute, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts, USA
- Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Chen-Chi Wu
- Department of Otolaryngology, National Taiwan University Hospital, Taipei, Taiwan
- Department of Medical Research, National Taiwan University Hospital Hsin-Chu Branch, Hsin-Chu, Taiwan
| | - Yen-Fu Cheng
- Department of Medical Research, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
- School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
- Department of Otolaryngology–Head and Neck Surgery, Taipei Veterans General Hospital, Taipei, Taiwan
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Abstract
INTRODUCTION More than 5% of the world's population have a disabling hearing loss which can be managed by hearing aids or implanted electrical devices. However, outcomes are highly variable, and the sound perceived by recipients is far from perfect. Sparked by the discovery of progenitor cells in the cochlea and rapid progress in drug delivery to the cochlea, biological and pharmaceutical therapies are currently in development to improve the function of the cochlear implant or eliminate the need for it altogether. AREAS COVERED This review highlights progress in emerging regenerative strategies to restore hearing and adjunct therapies to augment the cochlear implant. Novel approaches include the reprogramming of progenitor cells to restore the sensory hair cell population in the cochlea, gene therapy and gene editing to treat hereditary and acquired hearing loss. A detailed review of optogenetics is also presented as a technique that could enable optical stimulation of the spiral ganglion neurons, replacing or complementing electrical stimulation. EXPERT OPINION Increasing evidence of substantial reversal of hearing loss in animal models, alongside rapid advances in delivery strategies to the cochlea and learnings from clinical trials will amalgamate into a biological or pharmaceutical therapy to replace or complement the cochlear implant.
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Affiliation(s)
- Elise Ajay
- Bionics Institute, East Melbourne, Victoria, Australia.,University of Melbourne, Department of Engineering
| | | | - Rachael Richardson
- Bionics Institute, East Melbourne, Victoria, Australia.,University of Melbourne, Medical Bionics Department, Parkville, Victoria, Australia.,University of Melbourne, Department of Surgery (Otolaryngology), East Melbourne, Victoria, Australia
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Crane R, Conley SM, Al-Ubaidi MR, Naash MI. Gene Therapy to the Retina and the Cochlea. Front Neurosci 2021; 15:652215. [PMID: 33815052 PMCID: PMC8010260 DOI: 10.3389/fnins.2021.652215] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 02/22/2021] [Indexed: 12/20/2022] Open
Abstract
Vision and hearing disorders comprise the most common sensory disorders found in people. Many forms of vision and hearing loss are inherited and current treatments only provide patients with temporary or partial relief. As a result, developing genetic therapies for any of the several hundred known causative genes underlying inherited retinal and cochlear disorders has been of great interest. Recent exciting advances in gene therapy have shown promise for the clinical treatment of inherited retinal diseases, and while clinical gene therapies for cochlear disease are not yet available, research in the last several years has resulted in significant advancement in preclinical development for gene delivery to the cochlea. Furthermore, the development of somatic targeted genome editing using CRISPR/Cas9 has brought new possibilities for the treatment of dominant or gain-of-function disease. Here we discuss the current state of gene therapy for inherited diseases of the retina and cochlea with an eye toward areas that still need additional development.
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Affiliation(s)
- Ryan Crane
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
| | - Shannon M. Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
- Oklahoma Center for Neurosciences, University of Oklahoma Health Sciences Center, Oklahoma City, OK, United States
| | - Muayyad R. Al-Ubaidi
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
- College of Optometry, University of Houston, Houston, TX, United States
- Depatment of Biology and Biochemistry, University of Houston, Houston, TX, United States
| | - Muna I. Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX, United States
- College of Optometry, University of Houston, Houston, TX, United States
- Depatment of Biology and Biochemistry, University of Houston, Houston, TX, United States
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Zine A, Messat Y, Fritzsch B. A human induced pluripotent stem cell-based modular platform to challenge sensorineural hearing loss. STEM CELLS (DAYTON, OHIO) 2021; 39:697-706. [PMID: 33522002 PMCID: PMC8359331 DOI: 10.1002/stem.3346] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 01/07/2021] [Accepted: 01/08/2021] [Indexed: 12/16/2022]
Abstract
The sense of hearing depends on a specialized sensory organ in the inner ear, called the cochlea, which contains the auditory hair cells (HCs). Noise trauma, infections, genetic factors, side effects of ototoxic drugs (ie, some antibiotics and chemotherapeutics), or simply aging lead to the loss of HCs and their associated primary neurons. This results in irreversible sensorineural hearing loss (SNHL) as in mammals, including humans; the inner ear lacks the capacity to regenerate HCs and spiral ganglion neurons. SNHL is a major global health problem affecting millions of people worldwide and provides a growing concern in the aging population. To date, treatment options are limited to hearing aids and cochlear implants. A major bottleneck for development of new therapies for SNHL is associated to the lack of human otic cell bioassays. Human induced pluripotent stem cells (hiPSCs) can be induced in two-dimensional and three-dimensional otic cells in vitro models that can generate inner ear progenitors and sensory HCs and could be a promising preclinical platform from which to work toward restoring SNHL. We review the potential applications of hiPSCs in the various biological approaches, including disease modeling, bioengineering, drug testing, and autologous stem cell based-cell therapy, that offer opportunities to understand the pathogenic mechanisms of SNHL and identify novel therapeutic strategies.
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Affiliation(s)
- Azel Zine
- Laboratory of Bioengineering and Nanoscience, LBN, University of Montpellier, Montpellier, France
| | - Yassine Messat
- Laboratory of Bioengineering and Nanoscience, LBN, University of Montpellier, Montpellier, France
| | - Bernd Fritzsch
- Department of Biology, CLAS, University of Iowa, Iowa City, Iowa, USA
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Ding N, Lee S, Lieber-Kotz M, Yang J, Gao X. Advances in genome editing for genetic hearing loss. Adv Drug Deliv Rev 2021; 168:118-133. [PMID: 32387678 DOI: 10.1016/j.addr.2020.05.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Revised: 04/27/2020] [Accepted: 05/04/2020] [Indexed: 02/07/2023]
Abstract
According to the World Health Organization, hearing loss affects over 466 million people worldwide and is the most common human sensory impairment. It is estimated that genetic factors contribute to the causation of approximately 50% of congenital hearing loss. Yet, curative approaches to reversing or preventing genetic hearing impairment are still limited. The clustered regularly interspaced short palindromic repeats-associated protein 9 (CRISPR-Cas9) systems enable programmable and targeted gene editing in highly versatile manners and offer new gene therapy strategies for genetic hearing loss. Here, we summarize the most common deafness-associated genes, illustrate recent strategies undertaken by using CRISPR-Cas9 systems for targeted gene editing and further compare the CRISPR strategies to non-CRISPR gene therapies. We also examine the merits of different vehicles and delivery forms of genome editing agents. Lastly, we describe the development of animal models that could facilitate the eventual clinical applications of the CRISPR technology to the treatment of genetic hearing diseases.
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Inner Ear Gene Therapies Take Off: Current Promises and Future Challenges. J Clin Med 2020; 9:jcm9072309. [PMID: 32708116 PMCID: PMC7408650 DOI: 10.3390/jcm9072309] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Revised: 07/13/2020] [Accepted: 07/15/2020] [Indexed: 11/16/2022] Open
Abstract
Hearing impairment is the most frequent sensory deficit in humans of all age groups, from children (1/500) to the elderly (more than 50% of the over-75 s). Over 50% of congenital deafness are hereditary in nature. The other major causes of deafness, which also may have genetic predisposition, are aging, acoustic trauma, ototoxic drugs such as aminoglycosides, and noise exposure. Over the last two decades, the study of inherited deafness forms and related animal models has been instrumental in deciphering the molecular, cellular, and physiological mechanisms of disease. However, there is still no curative treatment for sensorineural deafness. Hearing loss is currently palliated by rehabilitation methods: conventional hearing aids, and for more severe forms, cochlear implants. Efforts are continuing to improve these devices to help users to understand speech in noisy environments and to appreciate music. However, neither approach can mediate a full recovery of hearing sensitivity and/or restoration of the native inner ear sensory epithelia. New therapeutic approaches based on gene transfer and gene editing tools are being developed in animal models. In this review, we focus on the successful restoration of auditory and vestibular functions in certain inner ear conditions, paving the way for future clinical applications.
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Zhao X, Jin C, Dong T, Sun Z, Zheng X, Feng B, Cheng Z, Li X, Tao Y, Wu H. Characterization of promoters for adeno-associated virus mediated efficient Cas9 activation in adult Cas9 knock-in murine cochleae. Hear Res 2020; 394:107999. [PMID: 32611519 DOI: 10.1016/j.heares.2020.107999] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 04/30/2020] [Accepted: 05/20/2020] [Indexed: 11/27/2022]
Abstract
CRISPR/Cas9 gene editing enables the treatment of hearing loss in congenitally deaf neonatal mice via both viral and non-viral delivery. While adeno-associated virus (AAV)-mediated gene delivery systems have been shown to be effective tools for gene replacement in the inner ear, application of the AAV-mediated CRISPR/Cas9 gene-editing approach for this purpose is yet to be documented. Based on our previous findings, we focused on the effects of several AAVs delivered via canalostomy injection in adult mice. Among the AAVs examined, AAV8 showed the greatest efficiency and specificity in transducing inner hair cells (IHC). The ability of Cre-expressing AAV8 to activate Cas9 in floxed-Cas9 knock-in (Cas9 KI) mice was further evaluated. We compared the effects of six different promoters (CMV, CAG, hSyn, CaMKIIa, GFAP, and ALB) of AAV8 delivered to the inner ear of adult Cas9 KI mice. Our findings showed that three AAV groups (CMV, CAG and hSyn promoters) infected the inner ear efficiently with different tropisms. Notably, AAVs with CMV, CAG, and hSyn promoters infected diverse cell types in mature murine cochleae, including IHCs. In particular, AAV8-hSyn showed high affinity to IHCs and spiral ganglion neurons (SGN). Neither the AAV8 virus itself (except AAV8-CAG) nor the surgical procedures used caused damage to HCs or impaired normal hearing. Our findings indicated that injection of AAV-Cre into mature inner ear efficiently induces Cas9 activation to achieve safe and efficient gene editing and different constituent promoters confer diverse infection patterns in cochlea, expanding the repertoire of gene-editing tools for regulating gene expression in target cells of the inner ear as part of the collective effort to rescue genetic hearing loss and develop effective gene therapy techniques.
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Affiliation(s)
- Xingle Zhao
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639, Zhizaoju Road, Shanghai, 200011, PR China; Ear Institute, Shanghai Jiaotong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China; Shanghai Key Laboratory of Translation Medicine on Ear and Nose Disease, No.115, Jinzun Road, Shanghai, 200011, PR China
| | - Chenxi Jin
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639, Zhizaoju Road, Shanghai, 200011, PR China; Ear Institute, Shanghai Jiaotong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China; Shanghai Key Laboratory of Translation Medicine on Ear and Nose Disease, No.115, Jinzun Road, Shanghai, 200011, PR China
| | - Tingting Dong
- Ear Institute, Shanghai Jiaotong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China; Shanghai Key Laboratory of Translation Medicine on Ear and Nose Disease, No.115, Jinzun Road, Shanghai, 200011, PR China; Biobank of Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China
| | - Zhuoer Sun
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639, Zhizaoju Road, Shanghai, 200011, PR China; Ear Institute, Shanghai Jiaotong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China; Shanghai Key Laboratory of Translation Medicine on Ear and Nose Disease, No.115, Jinzun Road, Shanghai, 200011, PR China
| | - Xiaofei Zheng
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639, Zhizaoju Road, Shanghai, 200011, PR China; Ear Institute, Shanghai Jiaotong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China; Shanghai Key Laboratory of Translation Medicine on Ear and Nose Disease, No.115, Jinzun Road, Shanghai, 200011, PR China
| | - Baoyi Feng
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639, Zhizaoju Road, Shanghai, 200011, PR China; Ear Institute, Shanghai Jiaotong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China; Shanghai Key Laboratory of Translation Medicine on Ear and Nose Disease, No.115, Jinzun Road, Shanghai, 200011, PR China
| | - Zhenzhe Cheng
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639, Zhizaoju Road, Shanghai, 200011, PR China; Ear Institute, Shanghai Jiaotong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China; Shanghai Key Laboratory of Translation Medicine on Ear and Nose Disease, No.115, Jinzun Road, Shanghai, 200011, PR China
| | - Xiang Li
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639, Zhizaoju Road, Shanghai, 200011, PR China; Ear Institute, Shanghai Jiaotong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China; Shanghai Key Laboratory of Translation Medicine on Ear and Nose Disease, No.115, Jinzun Road, Shanghai, 200011, PR China
| | - Yong Tao
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639, Zhizaoju Road, Shanghai, 200011, PR China; Ear Institute, Shanghai Jiaotong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China; Shanghai Key Laboratory of Translation Medicine on Ear and Nose Disease, No.115, Jinzun Road, Shanghai, 200011, PR China.
| | - Hao Wu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiaotong University School of Medicine, No.639, Zhizaoju Road, Shanghai, 200011, PR China; Ear Institute, Shanghai Jiaotong University School of Medicine, No.115, Jinzun Road, Shanghai, 200011, PR China; Shanghai Key Laboratory of Translation Medicine on Ear and Nose Disease, No.115, Jinzun Road, Shanghai, 200011, PR China.
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Hair Cell Transduction Efficiency of Single- and Dual-AAV Serotypes in Adult Murine Cochleae. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2020; 17:1167-1177. [PMID: 32518805 PMCID: PMC7270144 DOI: 10.1016/j.omtm.2020.05.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 05/07/2020] [Indexed: 01/03/2023]
Abstract
Gene delivery is a key component for the treatment of genetic hearing loss. To date, a myriad of adeno-associated virus (AAV) serotypes and surgical approaches have been employed to deliver transgenes to cochlear hair cells, but the efficacy of dual transduction remains unclear. Herein, we investigated cellular tropism of single injections of AAV serotype 1 (AAV1), AAV2, AAV8, AAV9, and Anc80L65, and quantitated dual-vector co-transduction rates following co-injection of AAV2 and AAV9 vectors in adult murine cochlea. We used the combined round window membrane and canal fenestration (RWM+CF) injection technique for vector delivery. Single AAV2 injections were most robust and transduced 96.7% ± 1.1% of inner hair cells (IHCs) and 83.9% ± 2.0% of outer hair cells (OHCs) throughout the cochlea without causing hearing impairment or hair cell loss. Dual AAV2 injection co-transduced 96.9% ± 1.7% of IHCs and 65.6% ± 8.95% of OHCs. Together, RWM+CF-injected single or dual AAV2 provides the highest auditory hair cell transduction efficiency of the AAV serotypes we studied. These findings broaden the application of cochlear gene therapy targeting hair cells.
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Potrusil T, Heshmat A, Sajedi S, Wenger C, Johnson Chacko L, Glueckert R, Schrott-Fischer A, Rattay F. Finite element analysis and three-dimensional reconstruction of tonotopically aligned human auditory fiber pathways: A computational environment for modeling electrical stimulation by a cochlear implant based on micro-CT. Hear Res 2020; 393:108001. [PMID: 32535276 DOI: 10.1016/j.heares.2020.108001] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 05/14/2020] [Accepted: 05/23/2020] [Indexed: 01/01/2023]
Abstract
The application of cochlear implants can be studied with computational models. The electrical potential distribution induced by an implanted device is evaluated with a volume conductor model, which is used as input for neuron models to simulate the reaction of cochlear neurons to micro-stimulation. In order to reliably predict the complex excitation profiles it is vital to consider an accurate representation of the human cochlea geometry including detailed three-dimensional pathways of auditory neurons reaching from the organ of Corti through the cochlea-volume. In this study, high-resolution micro-CT imaging (Δx = Δy = Δz = 3 μm) was used to reconstruct the pathways of 30 tonotopically organized nerve fiber bundles, distributed over eight octaves (11500-40 Hz). Results of the computational framework predict: (i) the peripheral process is most sensitive to cathodic stimulation (CAT), (ii) in many cases CAT elicits spikes in the peripheral terminal at threshold but with larger stimuli there is a second spike initiation site within the peripheral process, (iii) anodic stimuli (ANO) can excite the central process even at threshold, (iv) the recruitment of fibers by electrodes located in the narrowing middle- and apical turn is complex and impedes focal excitation of low frequency fibers, (v) degenerated cells which lost the peripheral process are more sensitive to CAT when their somata are totally covered with 2 membranes of a glial cell but they become ANO sensitive when the myelin covering is reduced.
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Affiliation(s)
- Thomas Potrusil
- Innsbruck Medical University, Department of Otorhinolaryngology, Laboratory for Inner Ear Biology, Anichstrasse 35, A-6020, Innsbruck, Austria
| | - Amirreza Heshmat
- Innsbruck Medical University, Department of Otorhinolaryngology, Laboratory for Inner Ear Biology, Anichstrasse 35, A-6020, Innsbruck, Austria; TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstraße 8-10, A- 1040, Vienna, Austria
| | - Sogand Sajedi
- TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstraße 8-10, A- 1040, Vienna, Austria
| | - Cornelia Wenger
- TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstraße 8-10, A- 1040, Vienna, Austria
| | - Lejo Johnson Chacko
- Innsbruck Medical University, Department of Otorhinolaryngology, Laboratory for Inner Ear Biology, Anichstrasse 35, A-6020, Innsbruck, Austria
| | - Rudolf Glueckert
- Innsbruck Medical University, Department of Otorhinolaryngology, Laboratory for Inner Ear Biology, Anichstrasse 35, A-6020, Innsbruck, Austria
| | - Anneliese Schrott-Fischer
- Innsbruck Medical University, Department of Otorhinolaryngology, Laboratory for Inner Ear Biology, Anichstrasse 35, A-6020, Innsbruck, Austria.
| | - Frank Rattay
- TU Wien, Institute for Analysis and Scientific Computing, Wiedner Hauptstraße 8-10, A- 1040, Vienna, Austria
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Leake PA, Akil O, Lang H. Neurotrophin gene therapy to promote survival of spiral ganglion neurons after deafness. Hear Res 2020; 394:107955. [PMID: 32331858 DOI: 10.1016/j.heares.2020.107955] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 03/16/2020] [Accepted: 03/26/2020] [Indexed: 12/13/2022]
Abstract
Hearing impairment is a major health and economic concern worldwide. Currently, the cochlear implant (CI) is the standard of care for remediation of severe to profound hearing loss, and in general, contemporary CIs are highly successful. But there is great variability in outcomes among individuals, especially in children, with many CI users deriving much less or even marginal benefit. Much of this variability is related to differences in auditory nerve survival, and there has been substantial interest in recent years in exploring potential therapies to improve survival of the cochlear spiral ganglion neurons (SGN) after deafness. Preclinical studies using osmotic pumps and other approaches in deafened animal models to deliver neurotrophic factors (NTs) directly to the cochlea have shown promising results, especially with Brain-Derived Neurotrophic Factor (BDNF). More recent studies have focused on the use of NT gene therapy to force expression of NTs by target cells within the cochlea. This could provide the means for a one-time treatment to promote long-term NT expression and improve neural survival after deafness. This review summarizes the evidence for the efficacy of exogenous NTs in preventing SGN degeneration after hearing loss and reviews the animal research to date suggesting that NT gene therapy can elicit long-term NT expression in the cochlea, resulting in significantly improved SGN and radial nerve fiber survival after deafness. In addition, we discuss NT gene therapy in other non-auditory applications and consider some of the remaining issues with regard to selecting optimal vectors, timing of treatment, and place/method of delivery, etc. that must be resolved prior to considering clinical application.
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Affiliation(s)
- Patricia A Leake
- S & I Epstein Laboratory, Dept. of Otolaryngology Head and Neck Surgery, University of California San Francisco, 2340 Sutter Street, Room N331, San Francisco, CA, 94115-1330, USA.
| | - Omar Akil
- S & I Epstein Laboratory, Dept. of Otolaryngology Head and Neck Surgery, University of California San Francisco, 2340 Sutter Street, Room N331, San Francisco, CA, 94115-1330, USA
| | - Hainan Lang
- Dept. of Pathology and Laboratory Medicine, Medical University of South Carolina, 165 Ashley Avenue, Room RS613, Charleston, SC, 29414, USA
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11
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Maguire CA, Corey DP. Viral vectors for gene delivery to the inner ear. Hear Res 2020; 394:107927. [PMID: 32199720 DOI: 10.1016/j.heares.2020.107927] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 02/13/2020] [Accepted: 02/17/2020] [Indexed: 02/04/2023]
Abstract
Gene therapy using virus vectors to treat hereditary diseases has made remarkable progress in the past decade. There are FDA-approved products for ex-vivo gene therapy for diseases such as immunodeficiencies (e.g., SCID), and in vivo gene therapy for a rare blindness and neuro-muscular disease. Gene therapy for hereditary hearing loss has picked up pace in the past five years due to progress in understanding disease gene function as well as the development of better technologies such as adeno-associated virus (AAV) vectors, to deliver nucleic acid to target cells in the inner ear. This review has two major goals. One is to review the state of the art for investigators already working in preclinical cochlear gene therapy. The other is to present the language of vectorology and important considerations for designing and using AAV vectors to inner ear neurobiologists who might use AAV vectors in the cochlea for either therapeutic or basic biological applications.
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Affiliation(s)
- Casey A Maguire
- Molecular Neurogenetics Unit, Massachusetts General Hospital, Charlestown, 149 13th Street, Charlestown, MA, 02114, USA; Department of Neurology, Harvard Medical School, Boston, MA, 02115, USA.
| | - David P Corey
- Department of Neurobiology, Harvard Medical School, 220 Longwood Avenue, Boston, MA, 02115, USA.
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Adeno-associated virus vector enables safe and efficient Cas9 activation in neonatal and adult Cas9 knockin murine cochleae. Gene Ther 2020; 27:392-405. [PMID: 32005950 DOI: 10.1038/s41434-020-0124-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 11/30/2019] [Accepted: 01/22/2020] [Indexed: 12/26/2022]
Abstract
Adeno-associated virus (AAV)-mediated gene delivery systems have been shown to be effective tools for gene manipulation in the inner ear. For example, hair cells (HCs) and multiple other cell types can be transduced by the local injection of AAVs into the inner ear. However, application of the AAV-mediated CRISPR/Cas9 gene-editing approach to the inner ear in adult mice has not yet been studied. Based on our previous work, we investigated several AAV serotypes in neonatal and adult mice in parallel, and found that AAV8 had the top efficiency to transduce inner HCs. We then tested the ability of Cre-expressing AAV8 to activate Cas9 in floxed-Cas9 knockin mice, and observed significant Cas9 activation in the inner ear of both neonatal and adult animals. Neither the AAV8 virus itself nor the surgical procedures used to deliver it-cochleostomy for neonatal mice and canalostomy for adult mice-caused any damage to HCs or impaired normal hearing. Our studies indicate that the local injection of AAV8-Cre can induce Cas9 activation to perform safe and efficient gene editing in the inner ear, expanding the repertoire of gene-editing tools for regulating gene expression in the inner ear as a part of efforts to rescue genetic hearing loss, initiate regeneration of HCs, or develop gene therapy techniques.
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13
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Abstract
Over 450 million people worldwide suffer from hearing loss, leading to an estimated economic burden of ∼$750 billion. The past decade has seen significant advances in the understanding of the molecular mechanisms that contribute to hearing, and the environmental and genetic factors that can go awry and lead to hearing loss. This in turn has sparked enormous interest in developing gene therapy approaches to treat this disorder. This review documents the most recent advances in cochlear gene therapy to restore hearing loss, and will cover viral vectors and construct designs, potential routes of delivery into the inner ear, and, lastly, the most promising genes of interest.
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Affiliation(s)
- Lawrence Lustig
- Department of Otolaryngology-Head and Neck Surgery, Columbia University Medical Center, New York Presbyterian Hospital, New York, New York 10032
| | - Omar Akil
- Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, San Francisco, California 94117
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14
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Ren Y, Landegger LD, Stankovic KM. Gene Therapy for Human Sensorineural Hearing Loss. Front Cell Neurosci 2019; 13:323. [PMID: 31379508 PMCID: PMC6660246 DOI: 10.3389/fncel.2019.00323] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/01/2019] [Indexed: 12/22/2022] Open
Abstract
Hearing loss is the most common sensory impairment in humans and currently disables 466 million people across the world. Congenital deafness affects at least 1 in 500 newborns, and over 50% are hereditary in nature. To date, existing pharmacologic therapies for genetic and acquired etiologies of deafness are severely limited. With the advent of modern sequencing technologies, there is a vast compendium of growing genetic alterations that underlie human hearing loss, which can be targeted by therapeutics such as gene therapy. Recently, there has been tremendous progress in the development of gene therapy vectors to treat sensorineural hearing loss (SNHL) in animal models in vivo. Nevertheless, significant hurdles remain before such technologies can be translated toward clinical use. These include addressing the blood-labyrinth barrier, engineering more specific and effective delivery vehicles, improving surgical access, and validating novel targets. In this review, we both highlight recent progress and outline challenges associated with in vivo gene therapy for human SNHL.
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Affiliation(s)
- Yin Ren
- Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
- Eaton Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, United States
| | - Lukas D. Landegger
- Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
- Eaton Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, United States
- Department of Otolaryngology, Vienna General Hospital, Medical University of Vienna, Vienna, Austria
| | - Konstantina M. Stankovic
- Department of Otolaryngology, Harvard Medical School, Boston, MA, United States
- Eaton Peabody Laboratories, Department of Otolaryngology, Massachusetts Eye and Ear, Boston, MA, United States
- Program in Speech and Hearing Bioscience and Technology, Harvard Medical School, Boston, MA, United States
- Harvard Program in Therapeutic Science, Harvard University, Boston, MA, United States
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15
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Inner Ear Connexin Channels: Roles in Development and Maintenance of Cochlear Function. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033233. [PMID: 30181354 DOI: 10.1101/cshperspect.a033233] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Connexin 26 and connexin 30 are the prevailing isoforms in the epithelial and connective tissue gap junction systems of the developing and mature cochlea. The most frequently encountered variants of the genes that encode these connexins, which are transcriptionally coregulated, determine complete loss of protein function and are the predominant cause of prelingual hereditary deafness. Reducing connexin 26 expression by Cre/loxP recombination in the inner ear of adult mice results in a decreased endocochlear potential, increased hearing thresholds, and loss of >90% of outer hair cells, indicating that this connexin is essential for maintenance of cochlear function. In the developing cochlea, connexins are necessary for intercellular calcium signaling activity. Ribbon synapses and basolateral membrane currents fail to mature in inner hair cells of mice that are born with reduced connexin expression, even though hair cells do not express any connexin. In contrast, pannexin 1, an alternative mediator of intercellular signaling, is dispensable for hearing acquisition and auditory function.
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Ma Y, Wise AK, Shepherd RK, Richardson RT. New molecular therapies for the treatment of hearing loss. Pharmacol Ther 2019; 200:190-209. [PMID: 31075354 DOI: 10.1016/j.pharmthera.2019.05.003] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/02/2019] [Indexed: 12/11/2022]
Abstract
An estimated 466 million people suffer from hearing loss worldwide. Sensorineural hearing loss is characterized by degeneration of key structures of the sensory pathway in the cochlea such as the sensory hair cells, the primary auditory neurons and their synaptic connection to the hair cells - the ribbon synapse. Various strategies to protect or regenerate these sensory cells and structures are the subject of intensive research. Yet despite recent advances in our understandings of the capacity of the cochlea for repair and regeneration there are currently no pharmacological or biological interventions for hearing loss. Current research focusses on localized cochlear drug, gene and cell-based therapies. One of the more promising drug-based therapies is based on neurotrophic factors for the repair of the ribbon synapse after noise exposure, as well as preventing loss of primary auditory neurons and regrowth of the auditory neuron fibers after severe hearing loss. Drug therapy delivery technologies are being employed to address the specific needs of neurotrophin and other therapies for hearing loss that include the need for high doses, long-term delivery, localised or cell-specific targeting and techniques for their safe and efficacious delivery to the cochlea. Novel biomaterials are enabling high payloads of drugs to be administered to the cochlea with subsequent slow-release properties that are proving to be beneficial for treating hearing loss. In parallel, new gene therapy technologies are addressing the need for cell specificity and high efficacy for the treatment of both genetic and acquired hearing loss with promising reports of hearing recovery. Some biomaterials and cell therapies are being used in conjunction with the cochlear implant ensuring therapeutic benefit to the primary neurons during electrical stimulation. This review will introduce the auditory system, hearing loss and the potential for repair and regeneration in the cochlea. Drug delivery to the cochlea will then be reviewed, with a focus on new biomaterials, gene therapy technologies, cell therapy and the use of the cochlear implant as a vehicle for drug delivery. With the current pre-clinical research effort into therapies for hearing loss, including clinical trials for gene therapy, the future for the treatment for hearing loss is looking bright.
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Affiliation(s)
- Yutian Ma
- Bionics Institute, East Melbourne, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Australia; University of Melbourne, Department of Chemical Engineering, Parkville, Victoria, Australia
| | - Andrew K Wise
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Robert K Shepherd
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia
| | - Rachael T Richardson
- Bionics Institute, East Melbourne, Australia; University of Melbourne, Medical Bionics Department, East Melbourne, Australia; University of Melbourne, Department of Surgery - Otolaryngology, East Melbourne, Australia.
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Gu X, Chai R, Guo L, Dong B, Li W, Shu Y, Huang X, Li H. Transduction of Adeno-Associated Virus Vectors Targeting Hair Cells and Supporting Cells in the Neonatal Mouse Cochlea. Front Cell Neurosci 2019; 13:8. [PMID: 30733670 PMCID: PMC6353798 DOI: 10.3389/fncel.2019.00008] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Accepted: 01/10/2019] [Indexed: 02/05/2023] Open
Abstract
Adeno-associated virus (AAV) is the preferred vector for gene therapy of hereditary deafness, and different viral serotypes, promoters and transduction pathways can influence the targeting of AAV to different types of cells and the expression levels of numerous exogenous genes. To determine the transduction and expression patterns of AAV with different serotypes or promoters in hair cells and supporting cells in the neonatal mouse cochlea, we examined the expression of enhanced green fluorescent protein (eGFP) for five different types of AAV vectors [serotypes 2, 9, and Anc80L65 with promoter cytomegalovirus (CMV)-beta-Globin and serotypes 2 and 9 with promoter chicken beta-actin (CBA)] in in vitro cochlear explant cultures and we tested the transduction of AAV2/2-CBA, AAV2/9-CBA, and AAV2/Anc80L65-CMV by in vivo microinjection into the scala media of the cochlea. We found that each AAV vector had its own transduction and expression characteristics in hair cells and supporting cells in different regions of the cochlea. There was a tonotopic gradient for the in vitro transduction of AAV2/2-CBA, AAV2/9-CBA, AAV2/2-CMV, and AAV2/9-CMV in outer hair cells (OHCs), with more OHCs expressing eGFP at the base of the cochlea than at the apex. AAV2/2-CBA in vitro and AAV2/Anc80L65-CMV in vivo induced more supporting cells expressing eGFP at the apex than in the base. We found that AAV vectors with different promoters had different expression efficacies in hair cells and supporting cells of the auditory epithelium. The CMV-beta-Globin promoter could drive the expression of the delivered construct more efficiently in hair cells, while the CBA promoter was more efficient in supporting cells. The in vitro and in vivo experiments both demonstrated that AAV2/Anc80L65-CMV was a very promising vector for gene therapy of deafness because of its high transduction rates in hair cells. These results might be useful for selecting the appropriate vectors for gene delivery into different types of inner ear cells and thus improving the effectiveness of gene therapy.
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Affiliation(s)
- Xi Gu
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai, China.,Department of Otolaryngology-Head and Neck Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Renjie Chai
- Key Laboratory for Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.,Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China.,Jiangsu Province High-Tech Key Laboratory for Bio-Medical Research, Southeast University, Nanjing, China
| | - Luo Guo
- ENT Institute and Otorhinolaryngology Department, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Biao Dong
- National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University and Collaborative Innovation Center for Biotherapy, Chengdu, China
| | - Wenyan Li
- ENT Institute and Otorhinolaryngology Department, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China
| | - Yilai Shu
- ENT Institute and Otorhinolaryngology Department, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China
| | - Xinsheng Huang
- Department of Otorhinolaryngology-Head and Neck Surgery, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Huawei Li
- ENT Institute and Otorhinolaryngology Department, Eye and ENT Hospital, State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, China.,NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai, China.,Institutes of Biomedical Sciences, Fudan University, Shanghai, China.,Shanghai Engineering Research Center of Cochlear Implant, Shanghai, China.,The Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, China
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18
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Carpena NT, Lee MY. Genetic Hearing Loss and Gene Therapy. Genomics Inform 2018; 16:e20. [PMID: 30602081 PMCID: PMC6440668 DOI: 10.5808/gi.2018.16.4.e20] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 12/04/2018] [Indexed: 12/15/2022] Open
Abstract
Genetic hearing loss crosses almost all the categories of hearing loss which includes the following: conductive, sensory, and neural; syndromic and nonsyndromic; congenital, progressive, and adult onset; high-frequency, low-frequency, or mixed frequency; mild or profound; and recessive, dominant, or sex-linked. Genes play a role in almost half of all cases of hearing loss but effective treatment options are very limited. Genetic hearing loss is considered to be extremely genetically heterogeneous. The advancements in genomics have been instrumental to the identification of more than 6,000 causative variants in more than 150 genes causing hearing loss. Identification of genes for hearing impairment provides an increased insight into the normal development and function of cells in the auditory system. These defective genes will ultimately be important therapeutic targets. However, the auditory system is extremely complex which requires tremendous advances in gene therapy including gene vectors, routes of administration, and therapeutic approaches. This review summarizes and discusses recent advances in elucidating the genomics of genetic hearing loss and technologies aimed at developing a gene therapy that may become a treatment option for in the near future.
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Affiliation(s)
- Nathanial T Carpena
- Department of Otolaryngology-Head and Neck Surgery, Dankook University College of Medicine, Cheonan 31116, Korea
| | - Min Young Lee
- Department of Otolaryngology-Head and Neck Surgery, Dankook University College of Medicine, Cheonan 31116, Korea.,Beckman Laser Institute Korea, Dankook University, Cheonan 31116, Korea
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Zhang W, Kim SM, Wang W, Cai C, Feng Y, Kong W, Lin X. Cochlear Gene Therapy for Sensorineural Hearing Loss: Current Status and Major Remaining Hurdles for Translational Success. Front Mol Neurosci 2018; 11:221. [PMID: 29997477 PMCID: PMC6028713 DOI: 10.3389/fnmol.2018.00221] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Accepted: 06/06/2018] [Indexed: 12/19/2022] Open
Abstract
Sensorineural hearing loss (SNHL) affects millions of people. Genetic mutations play a large and direct role in both congenital and late-onset cases of SNHL (e.g., age-dependent hearing loss, ADHL). Although hearing aids can help moderate to severe hearing loss the only effective treatment for deaf patients is the cochlear implant (CI). Gene- and cell-based therapies potentially may preserve or restore hearing with more natural sound perception, since their theoretical frequency resolution power is much higher than that of cochlear implants. These biologically-based interventions also carry the potential to re-establish hearing without the need for implanting any prosthetic device; the convenience and lower financial burden afforded by such biologically-based interventions could potentially benefit far more SNHL patients. Recently major progress has been achieved in preclinical studies of cochlear gene therapy. This review critically evaluates recent advances in the preclinical trials of gene therapies for SNHL and the major remaining challenges for the development and eventual clinical translation of this novel therapy. The cochlea bears many similarities to the eye for translational studies of gene therapies. Experience gained in ocular gene therapy trials, many of which have advanced to clinical phase III, may provide valuable guidance in improving the chance of success for cochlear gene therapy in human trials. A discussion on potential implications of translational knowledge gleaned from large numbers of advanced clinical trials of ocular gene therapy is therefore included.
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Affiliation(s)
- Wenjuan Zhang
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Sun Myoung Kim
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States
| | - Wenwen Wang
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | | | - Yong Feng
- Xiangya School of Medicine, Changsha, China
| | - Weijia Kong
- Department of Otolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xi Lin
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, United States
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20
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Abstract
Drug delivery to the inner ear is an ideal method to treat a wide variety of otologic conditions. A broad range of potential applications is just beginning to be explored. New approaches combine principles of inner ear pharmacokinetics with emerging technologies of drug delivery including novel delivery systems, drug-device combinations, and new categories of drugs. Strategies include cell-specific targeting, manipulation of gene expression, local activation following systemic delivery, and use of stem cells, viral vectors, and gene editing systems. Translation of these therapies to the clinic remains challenging given the potential risks of intracochlear and intralabyrinthine trauma, our limited understanding of the etiologies of particular inner ear disorders, and paucity of accurate diagnostic tools at the cellular level. This review provides an overview of future methods, delivery systems, disease targets, and clinical considerations required for translation to clinical medicine.
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21
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Tao Y, Huang M, Shu Y, Ruprecht A, Wang H, Tang Y, Vandenberghe LH, Wang Q, Gao G, Kong WJ, Chen ZY. Delivery of Adeno-Associated Virus Vectors in Adult Mammalian Inner-Ear Cell Subtypes Without Auditory Dysfunction. Hum Gene Ther 2018; 29:492-506. [PMID: 29130354 PMCID: PMC5909114 DOI: 10.1089/hum.2017.120] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/27/2017] [Indexed: 02/05/2023] Open
Abstract
Hearing loss, including genetic hearing loss, is one of the most common forms of sensory deficits in humans with limited options of treatment. Adeno-associated virus (AAV)-mediated gene transfer has been shown to recover auditory functions effectively in mouse models of genetic deafness when delivered at neonatal stages. However, the mouse cochlea is still developing at those time points, whereas in humans, the newborn inner ears are already fully mature. For effective gene therapy to treat genetic deafness, it is necessary to determine whether AAV-mediated therapy can be equally effective in the fully mature mouse inner ear without causing damage to the inner ear. This study tested several AAV serotypes by canalostomy in adult mice. It is shown that most AAVs transduce the sensory inner hair cells efficiently, but are less efficient at transducing outer hair cells. A subset of AAVs also transduces non-sensory cochlear cell types. Neither the surgical procedure of canalostomy nor the AAV serotypes damage hair cells or impair normal hearing. The studies indicate that canalostomy can be a viable route for safe and efficient gene delivery, and they expand the repertoire of AAVs to target diverse cell types in the adult inner ear.
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Affiliation(s)
- Yong Tao
- Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Mingqian Huang
- Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Yilai Shu
- Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
- Department of Otolaryngology—Head and Neck Surgery, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Adam Ruprecht
- Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
| | - Hongyang Wang
- Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
- Chinese PLA Institute of Otolaryngology, Chinese PLA General Hospital, Medical School of Chinese PLA, Beijing, China
| | - Yong Tang
- Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
- Department of Ear, Nose and Throat, People's Hospital of Jilin Province, Changchun, China
| | - Luk H. Vandenberghe
- Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
- Ocular Genomics Institute, Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts
| | - Qiuju Wang
- Chinese PLA Institute of Otolaryngology, Chinese PLA General Hospital, Medical School of Chinese PLA, Beijing, China
| | - Guangping Gao
- Horae Gene Therapy Center and Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts
- State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, China
| | - Wei-Jia Kong
- Department of Otorhinolaryngology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Zheng-Yi Chen
- Department of Otolaryngology and Program in Neuroscience, Harvard Medical School and Eaton Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts
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22
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Shi X, Wu N, Zhang Y, Guo W, Lin C, Yang S. Adeno-associated virus transformation into the normal miniature pig and the normal guinea pigs cochlea via scala tympani. Acta Otolaryngol 2017; 137:910-916. [PMID: 28471702 DOI: 10.1080/00016489.2017.1312015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
OBJECTIVE To investigate the expression of the miniature pig cochlea after AAV1 transfect into the cochlea via round window membrane (RWM). METHODS Twenty miniature pigs are equally divided into four experimental groups. Twelve miniature pigs are equally divided into four control groups. Each pig was transfected with the AAV1 in the experimental group via RWM and each pig was transduced with the artificial perilymph in the control group. The expression of green fluorescent protein (GFP) was observed at 2 weeks, 3 weeks and 4 weeks, respectively. Likewise, AAV1 was delivered into the guinea pigs cochleas using the same method, and the results were compared with that of the miniature pigs. RESULTS The expression was mainly in the inner hair cells of the miniature pig. The expression of GFP began to appear at 2 weeks, reached the peak at 3 weeks. It also expressed in Hensen's cells, inner pillar cells, outer pillar cells, spiral limbus, and spiral ligament. In the meanwhile, AAV1 was delivered into guinea pig cochlea via the same method, and AAV1 was also expressed in the inner hair cells. But the expression peaked at 2 weeks, and the efficiency of the inner hair cell transfection was higher than that of the pig. CONCLUSION AAV1 can be transformed into miniature pig cochlea via scala tympani by the RWM method efficiently.
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Affiliation(s)
- Xunbei Shi
- Department of Otolaryngology, Affiliated First Hospital, Fujian Medical University, Fuzhou, P.R. China
| | - Nan Wu
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology of PLA, Chinese PLA General Hospital, Beijing, P.R. China
| | - Yue Zhang
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology of PLA, Chinese PLA General Hospital, Beijing, P.R. China
| | - Weiwei Guo
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology of PLA, Chinese PLA General Hospital, Beijing, P.R. China
| | - Chang Lin
- Department of Otolaryngology, Affiliated First Hospital, Fujian Medical University, Fuzhou, P.R. China
| | - Shiming Yang
- Department of Otolaryngology, Head and Neck Surgery, Institute of Otolaryngology of PLA, Chinese PLA General Hospital, Beijing, P.R. China
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23
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In vivo genetic manipulation of inner ear connexin expression by bovine adeno-associated viral vectors. Sci Rep 2017; 7:6567. [PMID: 28779115 PMCID: PMC5544751 DOI: 10.1038/s41598-017-06759-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 06/19/2017] [Indexed: 01/03/2023] Open
Abstract
We have previously shown that in vitro transduction with bovine adeno–associated viral (BAAV) vectors restores connexin expression and rescues gap junction coupling in cochlear organotypic cultures from connexin–deficient mice that are models DFNB1 nonsyndromic hearing loss and deafness. The aims of this study were to manipulate inner ear connexin expression in vivo using BAAV vectors, and to identify the optimal route of vector delivery. Injection of a BAAV vector encoding a bacterial Cre recombinase via canalostomy in adult mice with floxed connexin 26 (Cx26) alleles promoted Cre/LoxP recombination, resulting in decreased Cx26 expression, decreased endocochlear potential, increased hearing thresholds, and extensive loss of outer hair cells. Injection of a BAAV vector encoding GFP-tagged Cx30 via canalostomy in P4 mice lacking connexin 30 (Cx30) promoted formation of Cx30 gap junctions at points of contacts between adjacent non-sensory cells of the cochlear sensory epithelium. Levels of exogenous Cx30 decayed over time, but were still detectable four weeks after canalostomy. Our results suggest that persistence of BAAV-mediated gene replacement in the cochlea is limited by the extensive remodeling of the organ of Corti throughout postnatal development and associated loss of non-sensory cells.
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Richardson RT, Thompson AC, Wise AK, Needham K. Challenges for the application of optical stimulation in the cochlea for the study and treatment of hearing loss. Expert Opin Biol Ther 2016; 17:213-223. [PMID: 27960585 DOI: 10.1080/14712598.2017.1271870] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Electrical stimulation has long been the most effective strategy for evoking neural activity from bionic devices and has been used with great success in the cochlear implant to allow deaf people to hear speech and sound. Despite its success, the spread of electrical current stimulates a broad region of neural tissue meaning that contemporary devices have limited precision. Optical stimulation as an alternative has attracted much recent interest for its capacity to provide highly focused stimuli, and therefore, potentially improved sensory perception. Given its specificity of activation, optical stimulation may also provide a useful tool in the study of fundamental neuroanatomy and neurophysiological processes. Areas covered: This review examines the advances in optical stimulation - infrared, nanoparticle-enhanced, and optogenetic-based - and its application in the inner ear for the restoration of auditory function following hearing loss. Expert opinion: Initial outcomes suggest that optogenetic-based approaches hold the greatest potential and viability amongst optical techniques for application in the cochlea. The future success of this approach will be governed by advances in the targeted delivery of opsins to auditory neurons, improvements in channel kinetics, development of optical arrays, and innovation of opsins that activate within the optimal near-infrared therapeutic window.
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Affiliation(s)
- Rachael T Richardson
- a Bionics Institute , East Melbourne , Australia.,b Department of Medical Bionics , University of Melbourne , East Melbourne , Australia
| | | | - Andrew K Wise
- a Bionics Institute , East Melbourne , Australia.,b Department of Medical Bionics , University of Melbourne , East Melbourne , Australia
| | - Karina Needham
- d Department of Surgery (Otolaryngology) , University of Melbourne, Royal Victorian Eye & Ear Hospital , East Melbourne , Australia
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25
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Shu Y, Tao Y, Wang Z, Tang Y, Li H, Dai P, Gao G, Chen ZY. Identification of Adeno-Associated Viral Vectors That Target Neonatal and Adult Mammalian Inner Ear Cell Subtypes. Hum Gene Ther 2016; 27:687-99. [PMID: 27342665 DOI: 10.1089/hum.2016.053] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The mammalian inner ear consists of diverse cell types with important functions. Gene mutations in these diverse cell types have been found to underlie different forms of genetic hearing loss. Targeting these mutations for gene therapy development represents a future therapeutic strategy to treat hearing loss. Adeno-associated viral (AAV) vectors have become the vector of choice for gene delivery in animal models in vivo. To identify AAV vectors that target inner ear cell subtypes, we systemically screened 12 AAV vectors with different serotypes (AAV1, 2, 5, 6, 6.2, 7, 8, 9, rh.8, rh.10, rh.39, and rh.43) that carry a reporter gene GFP in neonatal and adult mice by microinjection in vivo. We found that most AAVs infect both neonatal and adult inner ear, with different specificities and expression levels. The inner ear cochlear sensory epithelial region, which includes auditory hair cells and supporting cells, is most frequently targeted for gene delivery. Expression of the transgene is sustained, and neonatal inner ear delivery does not adversely affect hearing. Adult inner ear injection of AAV has a similar infection pattern as the younger inner ear, with the exception that outer hair cell death caused by the injection procedure can lead to hearing loss. In the adult, more so than in the neonatal mice, cell types infected and efficiency of infection are correlated with the site of injection. Most infected cells survive in neonatal and adult inner ears. The study adds to the list of AAV vectors that transduce the mammalian inner ear efficiently, providing the tools that are important to study inner ear gene function and for the development of gene therapy to treat hearing loss.
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Affiliation(s)
- Yilai Shu
- 1 Department of Otolaryngology, Harvard Medical School and Eaton-Peabody Laboratories, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts.,2 Department of Otolaryngology-Head and Neck Surgery, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China .,3 Key Laboratory of Hearing Medicine, National Health and Family Planning Commission, Shanghai, China
| | - Yong Tao
- 1 Department of Otolaryngology, Harvard Medical School and Eaton-Peabody Laboratories, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts
| | - Zhengmin Wang
- 2 Department of Otolaryngology-Head and Neck Surgery, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China .,3 Key Laboratory of Hearing Medicine, National Health and Family Planning Commission, Shanghai, China
| | - Yong Tang
- 1 Department of Otolaryngology, Harvard Medical School and Eaton-Peabody Laboratories, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts.,4 Department of Ear, Nose and Throat, People's Hospital of Jilin Province, Changchun, Jilin Province, China
| | - Huawei Li
- 2 Department of Otolaryngology-Head and Neck Surgery, Eye and ENT Hospital, Shanghai Medical College, Fudan University, Shanghai, China .,3 Key Laboratory of Hearing Medicine, National Health and Family Planning Commission, Shanghai, China
| | - Pu Dai
- 5 Department of Otolaryngology, Chinese PLA General Hospital, Beijing, People's Republic of China
| | - Guangping Gao
- 6 Horae Gene Therapy Center and Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, Massachusetts.,7 State Key Laboratory of Biotherapy, West China Hospital, Sichuan University , Chengdu, Sichuan, China
| | - Zheng-Yi Chen
- 1 Department of Otolaryngology, Harvard Medical School and Eaton-Peabody Laboratories, Massachusetts Eye & Ear Infirmary, Boston, Massachusetts
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Shibata SB, Ranum PT, Moteki H, Pan B, Goodwin AT, Goodman SS, Abbas PJ, Holt JR, Smith RJ. RNA Interference Prevents Autosomal-Dominant Hearing Loss. Am J Hum Genet 2016; 98:1101-1113. [PMID: 27236922 PMCID: PMC4908151 DOI: 10.1016/j.ajhg.2016.03.028] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 03/30/2016] [Indexed: 01/20/2023] Open
Abstract
Hearing impairment is the most common sensory deficit. It is frequently caused by the expression of an allele carrying a single dominant missense mutation. Herein, we show that a single intracochlear injection of an artificial microRNA carried in a viral vector can slow progression of hearing loss for up to 35 weeks in the Beethoven mouse, a murine model of non-syndromic human deafness caused by a dominant gain-of-function mutation in Tmc1 (transmembrane channel-like 1). This outcome is noteworthy because it demonstrates the feasibility of RNA-interference-mediated suppression of an endogenous deafness-causing allele to slow progression of hearing loss. Given that most autosomal-dominant non-syndromic hearing loss in humans is caused by this mechanism of action, microRNA-based therapeutics might be broadly applicable as a therapy for this type of deafness.
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Chang Q, Wang J, Li Q, Kim Y, Zhou B, Wang Y, Li H, Lin X. Virally mediated Kcnq1 gene replacement therapy in the immature scala media restores hearing in a mouse model of human Jervell and Lange-Nielsen deafness syndrome. EMBO Mol Med 2016; 7:1077-86. [PMID: 26084842 PMCID: PMC4551345 DOI: 10.15252/emmm.201404929] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Mutations in the potassium channel subunit KCNQ1 cause the human severe congenital deafness Jervell and Lange-Nielsen (JLN) syndrome. We applied a gene therapy approach in a mouse model of JLN syndrome (Kcnq1(-/-) mice) to prevent the development of deafness in the adult stage. A modified adeno-associated virus construct carrying a Kcnq1 expression cassette was injected postnatally (P0-P2) into the endolymph, which resulted in Kcnq1 expression in most cochlear marginal cells where native Kcnq1 is exclusively expressed. We also found that extensive ectopic virally mediated Kcnq1 transgene expression did not affect normal cochlear functions. Examination of cochlear morphology showed that the collapse of the Reissner's membrane and degeneration of hair cells (HCs) and cells in the spiral ganglia were corrected in Kcnq1(-/-) mice. Electrophysiological tests showed normal endocochlear potential in treated ears. In addition, auditory brainstem responses showed significant hearing preservation in the injected ears, ranging from 20 dB improvement to complete correction of the deafness phenotype. Our results demonstrate the first successful gene therapy treatment for gene defects specifically affecting the function of the stria vascularis, which is a major site affected by genetic mutations in inherited hearing loss.
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Affiliation(s)
- Qing Chang
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA
| | - Jianjun Wang
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA
| | - Qi Li
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA Department of Otolaryngology-Head and Neck Surgery, Nanfang Hospital of Southern Medical University, Guangzhou, China
| | - Yeunjung Kim
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA
| | - Binfei Zhou
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA
| | - Yunfeng Wang
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China
| | - Huawei Li
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China
| | - Xi Lin
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China
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Establishment of a model of cochlear lesions in rats to study potential gene therapy for sensorineural hearing loss. Int J Pediatr Otorhinolaryngol 2015; 79:2147-54. [PMID: 26574172 DOI: 10.1016/j.ijporl.2015.09.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Revised: 09/23/2015] [Accepted: 09/30/2015] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Sensorineural hearing loss seriously influences a patient's daily life, and no effective treatments exist to date. Gene therapy is a potential treatment for regenerating hair cells to restore hearing. METHODS In this study, we established a cochlear lesions model to study hair cell regeneration by co-administration of kanamycin and furosemide. After the injections, we assessed the survival of outer hair cells (OHC), inner hair cells (IHC), supporting cells (SC), spiral ganglion neurons (SGN) and peripheral axons. Moreover, we used two viral vectors to detect the transgene distribution. RESULTS Our results showed at 12h post-treatment, numerous OHC were missing in the basal turn. At 24h post-treatment, all OHCs in basal half of the cochlea were lost, and by 48h, OHC loss had spread to the apical coil. Four days after the injections, all OHCs were absent. At 1mo post-treatment, the organ of Corti had collapsed. In contrast, most of the SC remained 4d after the injections. The loss of SGN and peripheral axons was consistent with this time course post-treatment. The results of transgene distribution suggested the correlative gene can be transferred into the organ of Corti using adenoviruses (AdV) vectors and lentiviruses (LV) vectors in our cochlear lesion model. COMPARISON WITH EXISTING METHOD(S) We assessed the details of HC death at more time point and chosen the time point for gene transfer in this model. CONCLUSIONS We conclude that this cochlear lesion model would be suitable for the study of hair cell regeneration.
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Chien WW, McDougald DS, Roy S, Fitzgerald TS, Cunningham LL. Cochlear gene transfer mediated by adeno-associated virus: Comparison of two surgical approaches. Laryngoscope 2015; 125:2557-64. [PMID: 25891801 DOI: 10.1002/lary.25317] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/16/2015] [Indexed: 11/10/2022]
Abstract
OBJECTIVES/HYPOTHESIS Gene therapy offers the possibility of delivering corrective genetic materials to the cochlea, potentially improving hearing. In animals, the most commonly used surgical methods for viral gene therapy delivery to the cochlea are the round window and the cochleostomy approaches. However, the patterns of viral infection and the effects on hearing have not been directly compared between these two approaches. In this study, we compare the patterns of cochlear infection and effects on hearing between these two surgical approaches using adeno-associated virus serotype 2/8 (AAV8) as the gene delivery vehicle. STUDY DESIGN Animal study and basic science research. METHODS One- to two-month-old CBA/J mice were used in this study. AAV8-green fluorescent protein (GFP) was delivered to the cochlea by either the round window or the cochleostomy approach (described below). Auditory brainstem response was used to examine hearing thresholds before and after surgery. Animals were examined at 1, 2, 3, and 4 weeks after surgery for the patterns of cochlear infection and hearing loss. RESULTS Cochlear gene transfer was successful through both surgical approaches. In both approaches, AAV8-GFP mostly infected the inner hair cells. There was occasional low-level infection of the outer hair cells and supporting cells. The two surgical approaches resulted in comparable viral infection efficiencies. The round window approach resulted in less surgical trauma, as indicated by hearing loss, than the cochleostomy approach. CONCLUSIONS Adeno-associated virus-mediated gene transfer to the cochlea can be accomplished using either the round window or the cochleostomy surgical approach. The round window approach resulted in less hearing loss compared to the cochleostomy approach. LEVEL OF EVIDENCE NA.
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Affiliation(s)
- Wade W Chien
- National Institute on Deafness and Other Communication Disorders (w.w.c., d.s.m., s.r., t.s.f., l.l.c), National Institutes of Health, Bethesda, Maryland, U.S.A.,Department of Otolaryngology-Head and Neck Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland, U.S.A
| | - Devin S McDougald
- National Institute on Deafness and Other Communication Disorders (w.w.c., d.s.m., s.r., t.s.f., l.l.c), National Institutes of Health, Bethesda, Maryland, U.S.A
| | - Soumen Roy
- National Institute on Deafness and Other Communication Disorders (w.w.c., d.s.m., s.r., t.s.f., l.l.c), National Institutes of Health, Bethesda, Maryland, U.S.A
| | - Tracy S Fitzgerald
- National Institute on Deafness and Other Communication Disorders (w.w.c., d.s.m., s.r., t.s.f., l.l.c), National Institutes of Health, Bethesda, Maryland, U.S.A
| | - Lisa L Cunningham
- National Institute on Deafness and Other Communication Disorders (w.w.c., d.s.m., s.r., t.s.f., l.l.c), National Institutes of Health, Bethesda, Maryland, U.S.A
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30
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Electroacoustic stimulation: now and into the future. BIOMED RESEARCH INTERNATIONAL 2014; 2014:350504. [PMID: 25276779 PMCID: PMC4168031 DOI: 10.1155/2014/350504] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 08/04/2014] [Indexed: 12/22/2022]
Abstract
Cochlear implants have provided hearing to hundreds of thousands of profoundly deaf people around the world. Recently, the eligibility criteria for cochlear implantation have been relaxed to include individuals who have some useful residual hearing. These recipients receive inputs from both electric and acoustic stimulation (EAS). Implant recipients who can combine these hearing modalities demonstrate pronounced benefit in speech perception, listening in background noise, and music appreciation over implant recipients that rely on electrical stimulation alone. The mechanisms bestowing this benefit are unknown, but it is likely that interaction of the electric and acoustic signals in the auditory pathway plays a role. Protection of residual hearing both during and following cochlear implantation is critical for EAS. A number of surgical refinements have been implemented to protect residual hearing, and the development of hearing-protective drug and gene therapies is promising for EAS recipients. This review outlines the current field of EAS, with a focus on interactions that are observed between these modalities in animal models. It also outlines current trends in EAS surgery and gives an overview of the drug and gene therapies that are clinically translatable and may one day provide protection of residual hearing for cochlear implant recipients.
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Nishimura K, Weichert RM, Liu W, Davis RL, Dabdoub A. Generation of induced neurons by direct reprogramming in the mammalian cochlea. Neuroscience 2014; 275:125-35. [PMID: 24928351 DOI: 10.1016/j.neuroscience.2014.05.067] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Revised: 04/15/2014] [Accepted: 05/14/2014] [Indexed: 01/27/2023]
Abstract
Primary auditory neurons (ANs) in the mammalian cochlea play a critical role in hearing as they transmit auditory information in the form of electrical signals from mechanosensory cochlear hair cells in the inner ear to the brainstem. Their progressive degeneration is associated with disease conditions, excessive noise exposure and aging. Replacement of ANs, which lack the ability to regenerate spontaneously, would have a significant impact on research and advancement in cochlear implants in addition to the amelioration of hearing impairment. The aim of this study was to induce a neuronal phenotype in endogenous non-neural cells in the cochlea, which is the essential organ of hearing. Overexpression of a neurogenic basic helix-loop-helix transcription factor, Ascl1, in the cochlear non-sensory epithelial cells induced neurons at high efficiency at embryonic, postnatal and juvenile stages. Moreover, induced neurons showed typical properties of neuron morphology, gene expression and electrophysiology. Our data indicate that Ascl1 alone or Ascl1 and NeuroD1 is sufficient to reprogram cochlear non-sensory epithelial cells into functional neurons. Generation of neurons from non-neural cells in the cochlea is an important step for the regeneration of ANs in the mature mammalian cochlea.
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Affiliation(s)
- K Nishimura
- Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada.
| | - R M Weichert
- Department of Surgery/Otolaryngology, UCSD School of Medicine, La Jolla, CA 92093, USA.
| | - W Liu
- Department of Cell Biology and Neuroscience, Nelson Laboratories, Rutgers University, 604 Allison Road, Piscataway, NJ 08854, USA.
| | - R L Davis
- Department of Cell Biology and Neuroscience, Nelson Laboratories, Rutgers University, 604 Allison Road, Piscataway, NJ 08854, USA.
| | - A Dabdoub
- Biological Sciences, Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada; Department of Otolaryngology - Head and Neck Surgery, University of Toronto, Toronto, ON, Canada; Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
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32
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Kohrman DC, Raphael Y. Gene therapy for deafness. Gene Ther 2013; 20:1119-23. [PMID: 23864018 PMCID: PMC4113964 DOI: 10.1038/gt.2013.39] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Revised: 06/06/2013] [Accepted: 06/10/2013] [Indexed: 12/18/2022]
Abstract
Hearing loss is the most common sensory deficit in humans and can result from genetic, environmental or combined etiologies that prevent normal function of the cochlea, the peripheral sensory organ. Recent advances in understanding the genetic pathways that are critical for the development and maintenance of cochlear function, as well as the molecular mechanisms that underlie cell trauma and death, have provided exciting opportunities for modulating these pathways to correct genetic mutations, to enhance the endogenous protective pathways for hearing preservation and to regenerate lost sensory cells with the possibility of ameliorating hearing loss. A number of recent animal studies have used gene-based therapies in innovative ways toward realizing these goals. With further refinement, some of the protective and regenerative approaches reviewed here may become clinically applicable.
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Affiliation(s)
- D C Kohrman
- Department of Otolaryngology-Head and Neck Surgery, Kresge Hearing Research Institute, The University of Michigan, Ann Arbor, MI, USA
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Yu Q, Wang Y, Chang Q, Wang J, Gong S, Li H, Lin X. Virally expressed connexin26 restores gap junction function in the cochlea of conditional Gjb2 knockout mice. Gene Ther 2013; 21:71-80. [PMID: 24225640 PMCID: PMC3881370 DOI: 10.1038/gt.2013.59] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Revised: 09/09/2013] [Accepted: 09/23/2013] [Indexed: 02/03/2023]
Abstract
Mutations in GJB2, which codes for the gap junction protein connexin26, are the most common causes of human nonsyndromic hereditary deafness. We inoculated modified adeno-associated viral vectors into the scala media of early postnatal conditional Gjb2 knockout mice to drive exogenous connexin26 expression. We found extensive virally-expressed connexin26 in cells lining the scala media, and intercellular gap junction network was re-established in the organ of Corti of mutant mouse cochlea. Widespread ectopic connexin26 expression neither formed ectopic gap junctions nor affected normal hearing thresholds in wild type mice, suggesting that autonomous cellular mechanisms regulate proper membrane trafficking of exogenously-expressed connexin26 and govern the functional manifestation of them. Functional recovery of gap-junction-mediated coupling among the supporting cells was observed. We found that both cell death in the organ of Corti and degeneration of spiral ganglion neurons in the cochlea of mutant mice were substantially reduced, although auditory brainstem responses did not show significant hearing improvement. This is the first report demonstrating that virally-mediated gene therapy restored extensive gap junction intercellular network among cochlear non-sensory cells in vivo. Such a treatment performed at early postnatal stages resulted in a partial rescue of disease phenotypes in the cochlea of the mutant mice.
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Affiliation(s)
- Q Yu
- 1] Department of Otolaryngology Head & Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China [2] Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA
| | - Y Wang
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China
| | - Q Chang
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA
| | - J Wang
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA
| | - S Gong
- Department of Otolaryngology Head & Neck Surgery, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - H Li
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, China
| | - X Lin
- Department of Otolaryngology, Emory University School of Medicine, Atlanta, GA, USA
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Meyer A, Petit C, Safieddine S. [Gene therapy for human hearing loss: challenges and promises]. Med Sci (Paris) 2013; 29:883-9. [PMID: 24148127 DOI: 10.1051/medsci/20132910016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Thanks to the advances accomplished in human genomics during the last twenty years, major progress has been made towards understanding the pathogenesis of various forms of congenital or acquired deafness. The identification of deafness genes, which are potential therapeutic targets, and generation and functional characterization of murine models for human deafness forms have advanced the knowledge of the molecular physiology of auditory sensory cells. These milestones have opened the way for the development of new therapeutic strategies, alternatives to conventional prostheses, hearing amplification for mild-to-severe hearing loss, or cochlear implantation for severe-to-profound deafness. In this review, we first summarize the progress made over the last decade in using gene therapy and antisense RNA delivery, including the development of new methods for cochlear gene transfer. We then discuss the potential of gene therapy for curing acquired or inherited deafness and the major obstacles that must be overcome before clinical application can be considered.
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Affiliation(s)
- Anaïs Meyer
- Institut Pasteur, unité de génétique et physiologie de l'audition, 25, rue du Docteur Roux, 75724 Paris Cedex 15, France - Inserm UMRS 1120, 75015 Paris, France
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Wang Y, Sun Y, Chang Q, Ahmad S, Zhou B, Kim Y, Li H, Lin X. Early postnatal virus inoculation into the scala media achieved extensive expression of exogenous green fluorescent protein in the inner ear and preserved auditory brainstem response thresholds. J Gene Med 2013; 15:123-33. [PMID: 23413036 DOI: 10.1002/jgm.2701] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2012] [Revised: 01/24/2013] [Accepted: 01/29/2013] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Gene transfer into the inner ear is a promising approach for treating sensorineural hearing loss. The special electrochemical environment of the scala media raises a formidable challenge for effective gene delivery at the same time as keeping normal cochlear function intact. The present study aimed to define a suitable strategy for preserving hearing after viral inoculation directly into the scala media performed at various postnatal developmental stages. METHODS We assessed transgene expression of green fluorescent protein (GFP) mediated by various types of adeno-associated virus (AAV) and lentivirus (LV) in the mouse cochlea. Auditory brainstem responses were measured 30 days after inoculation to assess effects on hearing. RESULTS Patterns of GFP expression confirmed extensive exogenous gene expression in various types of cells lining the endolymphatic space. The use of different viral vectors and promoters resulted in specific cellular GFP expression patterns. AAV2/1 with cytomegalovirus promoter apparently gave the best results for GFP expression in the supporting cells. Histological examination showed normal cochlear morphology and no hair cell loss after either AAV or LV injections. We found that hearing thresholds were not significantly changed when the injections were performed in mice younger than postnatal day 5, regardless of the type of virus tested. CONCLUSIONS Viral inoculation and expression in the inner ear for the restoration of hearing must not damage cochlear function. Using normal hearing mice as a model, we have achieved this necessary step, which is required for the treatment of many types of congenital deafness that require early intervention.
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Affiliation(s)
- Yunfeng Wang
- Department of Otolaryngology, Eye & ENT Hospital, Fudan University, Shanghai, PR China
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Wei Y, Fu Y, Liu S, Xia G, Pan S. Effect of lentiviruses carrying enhanced green fluorescent protein injected into the scala media through a cochleostomy in rats. Am J Otolaryngol 2013; 34:301-7. [PMID: 23465349 DOI: 10.1016/j.amjoto.2012.12.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Accepted: 12/24/2012] [Indexed: 10/27/2022]
Abstract
PURPOSE The purposes of the current study were to assess the feasibility of post-auricular microinjection of lentiviruses carrying enhanced green fluorescent protein (EGFP) into the scala media through cochleostomies in rats, determine the expression of viral gene in the cochlea, and record the post-operative changes in the number and auditory function of cochlear hair cells (HCs). METHODS Healthy rats were randomly divided into two groups. The left ears of the animals in group I were injected with lentivirus carrying EGFP (n=10) via scala media lateral wall cochleostomies, and the left ears of the animals in group II were similarly injected with artificial endolymph (n=10). Prior to and 30 days post-injection, auditory function was assessed with click-auditory brainstem response (ABR) testing, EGFP expression was determined with cochlear frozen sections under fluorescence microscopy, and survival of HCs was estimated based on whole mount preparations. RESULTS Thirty days after surgery, click-ABR testing revealed that there were significant differences in the auditory function, EGFP expression, and survival of HCs in the left ears before and after surgery in the same rats from each group. In group I, EGFP was noted in the strial marginal cells of the scala media, the organ of Corti, spiral nerves, and spiral ganglion cells. CONCLUSION Lentiviruses were successfully introduced into the scala media through cochleostomies in rats, and the EGFP reporter gene was efficiently expressed in the organ of Corti, spiral nerves, and spiral ganglion cells.
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XIA LI, YIN SHANKAI. Local gene transfection in the cochlea (Review). Mol Med Rep 2013; 8:3-10. [DOI: 10.3892/mmr.2013.1496] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2012] [Accepted: 12/13/2012] [Indexed: 11/06/2022] Open
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Filling the silent void: genetic therapies for hearing impairment. GENETICS RESEARCH INTERNATIONAL 2013; 2012:748698. [PMID: 23304527 PMCID: PMC3529436 DOI: 10.1155/2012/748698] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 09/27/2012] [Accepted: 11/04/2012] [Indexed: 12/02/2022]
Abstract
The inner ear cytoarchitecture forms one of the most intricate and delicate organs in the human body and is vulnerable to the effects of genetic disorders, aging, and environmental damage. Owing to the inability of the mammalian cochlea to regenerate sensory hair cells, the loss of hair cells is a leading cause of deafness in humans. Millions of individuals worldwide are affected by the emotionally and financially devastating effects of hearing impairment (HI). This paper provides a brief introduction into the key role of genes regulating inner ear development and function. Potential future therapies that leverage on an improved understanding of these molecular pathways are also described in detail.
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Abstract
Animal studies on inner ear development, repair and regeneration provide understanding of molecular pathways that can be harnessed for treating inner ear disease. Use of transgenic mouse technology, in particular, has contributed knowledge of genes that regulate development of hair cells and innervation, and of molecular players that can induce regeneration, but this technology is not applicable for human treatment, for practical and ethical reasons. Therefore other means for influencing gene expression in the inner ear are needed. We describe several gene vectors useful for inner ear gene therapy and the practical aspects of introducing these vectors into the ear. We then review the progress toward using gene transfer for therapies in both auditory and balance systems, and discuss the technological milestones needed to advance to clinical application of these methods.
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Affiliation(s)
- Hideto Fukui
- Kresge Hearing Research Institute, Department of Otolaryngology, University of Michigan, 1150 West Medical Center Dr., Ann Arbor, MI 48109-5648, USA
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Sacheli R, Delacroix L, Vandenackerveken P, Nguyen L, Malgrange B. Gene transfer in inner ear cells: a challenging race. Gene Ther 2012; 20:237-47. [PMID: 22739386 DOI: 10.1038/gt.2012.51] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent advances in human genomics led to the identification of numerous defective genes causing deafness, which represent novel putative therapeutic targets. Future gene-based treatment of deafness resulting from genetic or acquired sensorineural hearing loss may include strategies ranging from gene therapy to antisense delivery. For successful development of gene therapies, a minimal requirement involves the engineering of appropriate gene carrier systems. Transfer of exogenous genetic material into the mammalian inner ear using viral or non-viral vectors has been characterized over the last decade. The nature of inner ear cells targeted, as well as the transgene expression level and duration, are highly dependent on the vector type, the route of administration and the strength of the promoter driving expression. This review summarizes and discusses recent advances in inner ear gene-transfer technologies aimed at examining gene function or identifying new treatment for inner ear disorders.
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Affiliation(s)
- R Sacheli
- GIGA-Neurosciences, Developmental Neurobiology Unit, University of Liège, Liège, Belgium
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41
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Abstract
PURPOSE OF REVIEW This review highlights recent advances in cochlear gene therapy over the past several years. Cochlear gene therapy has undergone tremendous advances over the past decade. Beginning with some groundbreaking work in 2005 documenting hair cell regeneration using virally mediated delivery of the mouse atonal 1 gene, gene therapy is now being explored as a possible treatment for a variety of causes of hearing loss. RECENT FINDINGS Recent advances in cochlear gene therapy include improved methods of gene delivery with a better delineation of viral vectors that are suitable for this purpose, additional improvements in hair cell regeneration, and directed research toward autoimmune hearing loss, ototoxicity, spiral ganglion survival, and genetic forms of hearing loss. SUMMARY If successful, cochlear gene therapy will dramatically alter our ability to treat a variety of forms of acquired and genetic hearing loss.
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Affiliation(s)
- Lawrence R. Lustig
- Francis A. Sooy, MD Professor of Otolaryngology-Head & Neck Surgery, Department of Otolaryngology-Head & Neck Surgery, University of California San Francisco, 2380 Sutter Street, San Francisco, CA 94115, PH: 415-353-2203,
| | - Omar Akil
- Francis A. Sooy, MD Professor of Otolaryngology-Head & Neck Surgery, Department of Otolaryngology-Head & Neck Surgery, University of California San Francisco, 2380 Sutter Street, San Francisco, CA 94115, PH: 415-353-2203,
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42
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Crispino G, Di Pasquale G, Scimemi P, Rodriguez L, Galindo Ramirez F, De Siati RD, Santarelli RM, Arslan E, Bortolozzi M, Chiorini JA, Mammano F. BAAV mediated GJB2 gene transfer restores gap junction coupling in cochlear organotypic cultures from deaf Cx26Sox10Cre mice. PLoS One 2011; 6:e23279. [PMID: 21876744 PMCID: PMC3158073 DOI: 10.1371/journal.pone.0023279] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2011] [Accepted: 07/11/2011] [Indexed: 11/24/2022] Open
Abstract
The deafness locus DFNB1 contains GJB2, the gene encoding connexin26 and GJB6, encoding connexin30, which appear to be coordinately regulated in the inner ear. In this work, we investigated the expression and function of connexin26 and connexin30 from postnatal day 5 to adult age in double transgenic Cx26(Sox10Cre) mice, which we obtained by crossing connexin26 floxed mice with a deleter Sox10-Cre line. Cx26(Sox10Cre) mice presented with complete connexin26 ablation in the epithelial gap junction network of the cochlea, whereas connexin30 expression was developmentally delayed; immunolabeling patterns for both connexins were normal in the cochlear lateral wall. In vivo electrophysiological measurements in Cx26(Sox10Cre) mice revealed profound hearing loss accompanied by reduction of endocochlear potential, and functional experiments performed in postnatal cochlear organotypic cultures showed impaired gap junction coupling. Transduction of these cultures with a bovine adeno associated virus vector restored connexin26 protein expression and rescued gap junction coupling. These results suggest that restoration of normal connexin levels by gene delivery via recombinant adeno associated virus could be a way to rescue hearing function in DFNB1 mouse models and, in future, lead to the development of therapeutic interventions in humans.
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Affiliation(s)
- Giulia Crispino
- Fondazione per la Ricerca Biomedica Avanzata, Istituto Veneto di Medicina Molecolare, Padova, Italy
- Dipartimento di Fisica “G. Galilei”, Università di Padova, Padova, Italy
| | - Giovanni Di Pasquale
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Pietro Scimemi
- Dipartimento di Specialità Medico–Chirurgiche e Servizio di Audiologia, Università di Padova, Padova, Italy
| | - Laura Rodriguez
- Fondazione per la Ricerca Biomedica Avanzata, Istituto Veneto di Medicina Molecolare, Padova, Italy
- Dipartimento di Fisica “G. Galilei”, Università di Padova, Padova, Italy
| | - Fabian Galindo Ramirez
- Fondazione per la Ricerca Biomedica Avanzata, Istituto Veneto di Medicina Molecolare, Padova, Italy
| | - Romolo Daniele De Siati
- Dipartimento di Specialità Medico–Chirurgiche e Servizio di Audiologia, Università di Padova, Padova, Italy
| | - Rosa Maria Santarelli
- Dipartimento di Specialità Medico–Chirurgiche e Servizio di Audiologia, Università di Padova, Padova, Italy
| | - Edoardo Arslan
- Dipartimento di Specialità Medico–Chirurgiche e Servizio di Audiologia, Università di Padova, Padova, Italy
| | - Mario Bortolozzi
- Fondazione per la Ricerca Biomedica Avanzata, Istituto Veneto di Medicina Molecolare, Padova, Italy
- Dipartimento di Fisica “G. Galilei”, Università di Padova, Padova, Italy
- Istituto CNR di Neuroscienze, Padova, Italy
| | - John A. Chiorini
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Fabio Mammano
- Fondazione per la Ricerca Biomedica Avanzata, Istituto Veneto di Medicina Molecolare, Padova, Italy
- Dipartimento di Fisica “G. Galilei”, Università di Padova, Padova, Italy
- Istituto CNR di Neuroscienze, Padova, Italy
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43
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Sheffield AM, Gubbels SP, Hildebrand MS, Newton SS, Chiorini JA, Di Pasquale G, Smith RJH. Viral vector tropism for supporting cells in the developing murine cochlea. Hear Res 2011; 277:28-36. [PMID: 21530627 PMCID: PMC3137760 DOI: 10.1016/j.heares.2011.03.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 03/24/2011] [Accepted: 03/30/2011] [Indexed: 12/01/2022]
Abstract
Gene-based therapeutics are being developed as novel treatments for genetic hearing loss. One roadblock to effective gene therapy is the identification of vectors which will safely deliver therapeutics to targeted cells. The cellular heterogeneity that exists within the cochlea makes viral tropism a vital consideration for effective inner ear gene therapy. There are compelling reasons to identify a viral vector with tropism for organ of Corti supporting cells. Supporting cells are the primary expression site of connexin 26 gap junction proteins that are mutated in the most common form of congenital genetic deafness (DFNB1). Supporting cells are also primary targets for inducing hair cell regeneration. Since many genetic forms of deafness are congenital it is necessary to administer gene transfer-based therapeutics prior to the onset of significant hearing loss. We have used transuterine microinjection of the fetal murine otocyst to investigate viral tropism in the developing inner ear. For the first time we have characterized viral tropism for supporting cells following in utero delivery to their progenitors. We report the inner ear tropism and potential ototoxicity of three previously untested vectors: early-generation adenovirus (Ad5.CMV.GFP), advanced-generation adenovirus (Adf.11D) and bovine adeno-associated virus (BAAV.CMV.GFP). Adenovirus showed robust tropism for organ of Corti supporting cells throughout the cochlea but induced increased ABR thresholds indicating ototoxicity. BAAV also showed tropism for organ of Corti supporting cells, with preferential transduction toward the cochlear apex. Additionally, BAAV readily transduced spiral ganglion neurons. Importantly, the BAAV-injected ears exhibited normal hearing at 5 weeks of age when compared to non-injected ears. Our results support the use of BAAV for safe and efficient targeting of supporting cell progenitors in the developing murine inner ear.
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Staecker H, Praetorius M, Brough DE. Development of gene therapy for inner ear disease: Using bilateral vestibular hypofunction as a vehicle for translational research. Hear Res 2011; 276:44-51. [PMID: 21251965 DOI: 10.1016/j.heares.2011.01.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 01/10/2011] [Accepted: 01/11/2011] [Indexed: 12/16/2022]
Abstract
Despite the significant impact of hearing and balance disorders on the general population there are currently no dedicated pharmaceuticals that target the inner ear. Advances in molecular biology and neuroscience have improved our understanding of the inner ear allowing the development of a range of molecular targets that have the potential to treat both hearing and balance disorders. One of the principal advantages of the inner ear is that it is accessible through a variety of approaches that would allow a potential to be delivered locally rather than systemically. This significantly broadens the potential medications that can be developed and opens the possibility of local gene delivery as a therapeutic intervention. Several potential clinical targets have been identified including delivery of neurotrophin expressing genes as an adjunct to cochlear implantation, delivery of protective genes to prevent trauma and the development of strategies for regenerating inner ear sensory cells. In order to translate these potential therapeutics into humans we will want to optimize the gene delivery methodology, dosing and activity of the drug for therapeutic value. To this end we have developed a series of adenovectors that efficiently transduce the inner ear. The use of these gene delivery approaches are attractive for the potential of hair cell regeneration after loss induced by trauma or ototoxins. This approach is particularly suited for the development of molecular therapies targeted at the vestibular system given that no device based therapeutic such a cochlear implant available for vestibular loss.
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Affiliation(s)
- Hinrich Staecker
- Dept. Otolaryngology Head and Neck Surgery, University of Kansas School of Medicine, MS 3010, 3901 Rainbow Blvd, Kansas City, KS 66209, USA.
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45
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Adeno-associated virus-mediated gene delivery into the scala media of the normal and deafened adult mouse ear. Gene Ther 2011; 18:569-78. [PMID: 21209625 PMCID: PMC3085601 DOI: 10.1038/gt.2010.175] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Murine models are ideal for studying cochlear gene transfer, as many hearing loss-related mutations have been discovered and mapped within the mouse genome. However, because of the small size and delicate nature, the membranous labyrinth of the mouse is a challenging target for the delivery of viral vectors. To minimize injection trauma, we developed a procedure for the controlled release of adeno-associated viruses (AAVs) into the scala media of adult mice. This procedure poses minimal risk of injury to structures of the cochlea and middle ear, and allows for near-complete preservation of low and middle frequency hearing. In this study, transduction efficiency and cellular specificity of AAV vectors (serotypes 1, 2, 5, 6 and 8) were investigated in normal and drug-deafened ears. Using the cytomegalovirus promoter to drive gene expression, a variety of cell types were transduced successfully, including sensory hair cells and supporting cells, as well as cells in the auditory nerve and spiral ligament. Among all five serotypes, inner hair cells were the most effectively transduced cochlear cell type. All five serotypes of AAV vectors transduced cells of the auditory nerve, though serotype 8 was the most efficient vector for transduction. Our findings indicate that efficient AAV inoculation (via the scala media) can be performed in adult mouse ears, with hearing preservation a realistic goal. The procedure we describe may also have applications for intra-endolymphatic drug delivery in many mouse models of human deafness.
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46
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Wise AK, Hume CR, Flynn BO, Jeelall YS, Suhr CL, Sgro BE, O'Leary SJ, Shepherd RK, Richardson RT. Effects of localized neurotrophin gene expression on spiral ganglion neuron resprouting in the deafened cochlea. Mol Ther 2010; 18:1111-22. [PMID: 20216530 DOI: 10.1038/mt.2010.28] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A cochlear implant may be used to electrically stimulate spiral ganglion neurons (SGNs) in people with severe sensorineural hearing loss (SNHL). However, these neurons progressively degenerate after SNHL due to loss of neurotrophins normally supplied by sensory hair cells (HCs). Experimentally, exogenous neurotrophin administration prevents SGN degeneration but can also result in abnormal resprouting of their peripheral fibers. This study aimed to create a target-derived neurotrophin source to increase neuron survival and redirect fiber resprouting following SNHL. Adenoviral (Ad) vectors expressing green fluorescent protein (GFP) alone or in combination with brain-derived neurotrophic factor (BDNF) or neurotrophin-3 (NT3) were injected into the cochlear scala tympani or scala media of guinea-pigs (GPs) deafened via aminoglycosides for 1 week. After 3 weeks, cochleae were examined for gene expression, neuron survival, and the projection of peripheral fibers in response to gene expression. Injection of vectors into the scala media resulted in more localized gene expression than scala tympani injection with gene expression consistently observed within the partially degenerated organ of Corti. There was also greater neuron survival and evidence of localized fiber responses to neurotrophin-expressing cells within the organ of Corti from scala media injections (P < 0.05), a first step in promoting organized resprouting of auditory peripheral fibers via gene therapy.
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Affiliation(s)
- Andrew K Wise
- Bionic Ear Institute, East Melbourne, Victoria, Australia
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47
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Di Pasquale G, Kaludov N, Agbandje-McKenna M, Chiorini JA. BAAV transcytosis requires an interaction with beta-1-4 linked- glucosamine and gp96. PLoS One 2010; 5:e9336. [PMID: 20231878 PMCID: PMC2834734 DOI: 10.1371/journal.pone.0009336] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 02/02/2010] [Indexed: 11/19/2022] Open
Abstract
Cell surface carbohydrates play an important role in virus entry and intracellular trafficking. Bovine Adeno-Associated Virus (BAAV) uses plasma membrane gangliosides for transduction and infection. In addition, independent of the infectious pathway, BAAV also has the ability to pass through barrier epithelia and endothelia using a transcytosis pathway dependent upon the presence of cell surface carbohydrates. Thus, in order to better define the carbohydrate interactions that are necessary for BAAV infection or transcytosis, a glycan microarray composed of both natural and synthetic carbohydrates was probed with HA-tagged BAAV particles. This identified chitotriose, a trimer of β-1-4-linked N-acetyl glucosamine, as having an interaction with BAAV. Competition experiments showed that the BAAV interaction with this carbohydrate is not necessary for infection but is instead important in the transcytosis pathway. The β-1-4-linked N-acetyl glucosamine modification has been reported on gp96, a glycoprotein involved in the transcytosis of bacteria and toxins. Significantly, immunoprecipitation and competition experiments with an anti-gp96 antibody and a soluble form of gp96, respectively, showed this glycoprotein can also interact with BAAV to serve as a receptor for its transcytosis.
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Affiliation(s)
- Giovanni Di Pasquale
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nikola Kaludov
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, The McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, United States of America
| | - John A. Chiorini
- Molecular Physiology and Therapeutics Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: .
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