scholarly journals A Single Cisterna Magna Injection of AAV Leads to Binaural Transduction in Mice

2022 ◽  
Vol 9 ◽  
Author(s):  
Fabian Blanc ◽  
Alexis-Pierre Bemelmans ◽  
Corentin Affortit ◽  
Charlène Joséphine ◽  
Jean-Luc Puel ◽  
...  
Keyword(s):  
Inner Ear ◽  
High Efficiency ◽  
Spiral Ganglion ◽  
Cisterna Magna ◽  
Gene Therapies ◽  
Large Numbers ◽  
Delivery Routes ◽  
Basal Portion ◽  
Ganglion Neurons ◽  
Almost All

Viral-mediated gene augmentation, silencing, or editing offers tremendous promise for the treatment of inherited and acquired deafness. Inner-ear gene therapies often require a safe, clinically useable and effective route of administration to target both ears, while avoiding damage to the delicate structures of the inner ear. Here, we examined the possibility of using a cisterna magna injection as a new cochlear local route for initiating binaural transduction by different serotypes of the adeno-associated virus (AAV2/8, AAV2/9, AAV2/Anc80L65). The results were compared with those following canalostomy injection, one of the existing standard inner ear local delivery routes. Our results demonstrated that a single injection of AAVs enables high-efficiency binaural transduction of almost all inner hair cells with a basal-apical pattern and of large numbers of spiral ganglion neurons of the basal portion of the cochlea, without affecting auditory function and cochlear structures. Taken together, these results reveal the potential for using a cisterna magna injection as a local route for binaural gene therapy applications, but extensive testing will be required before translation beyond mouse models.

Brn3a is a transcriptional regulator of soma size, target field innervation and axon pathfinding of inner ear sensory neurons

Development ◽  
2001 ◽  
Vol 128 (13) ◽  
pp. 2421-2432 ◽  
Author(s):  
Eric J. Huang ◽  
Wei Liu ◽  
Bernd Fritzsch ◽  
Lynne M. Bianchi ◽  
Louis F. Reichardt ◽  
...  
Keyword(s):  
Inner Ear ◽  
Ganglion Cells ◽  
Substantial Reduction ◽  
Spiral Ganglion ◽  
Neurotrophin Receptor ◽  
Axon Pathfinding ◽  
Target Field ◽  
Afferent Fibers ◽  
Soma Size ◽  
Ganglion Neurons

The POU domain transcription factors Brn3a, Brn3b and Brn3c are required for the proper development of sensory ganglia, retinal ganglion cells, and inner ear hair cells, respectively. We have investigated the roles of Brn3a in neuronal differentiation and target innervation in the facial-stato-acoustic ganglion. We show that absence of Brn3a results in a substantial reduction in neuronal size, abnormal neuronal migration and downregulation of gene expression, including that of the neurotrophin receptor TrkC, parvalbumin and Brn3b. Selective loss of TrkC neurons in the spiral ganglion of Brn3a−/− cochlea leads to an innervation defect similar to that of TrkC−/− mice. Most remarkably, our results uncover a novel role for Brn3a in regulating axon pathfinding and target field innervation by spiral and vestibular ganglion neurons. Loss of Brn3a results in severe retardation in development of the axon projections to the cochlea and the posterior vertical canal as early as E13.5. In addition, efferent axons that use the afferent fibers as a scaffold during pathfinding also show severe misrouting. Interestingly, despite the well-established roles of ephrins and EphB receptors in axon pathfinding, expression of these molecules does not appear to be affected in Brn3a−/− mice. Thus, Brn3a must control additional downstream genes that are required for axon pathfinding.

scholarly journals Intrinsically Self-renewing Neuroprogenitors From the A/J Mouse Spiral Ganglion as Virtually Unlimited Source of Mature Auditory Neurons

2020 ◽  
Vol 14 ◽  
Author(s):  
Francis Rousset ◽  
Vivianne B. C. Kokje ◽  
Rebecca Sipione ◽  
Dominik Schmidbauer ◽  
German Nacher-Soler ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Inner Ear ◽  
Progenitor Cells ◽  
Ganglion Cells ◽  
Spiral Ganglion ◽  
Specific Cell ◽  
Auditory Neurons ◽  
Self Renewal ◽  
Starting Point ◽  
Ganglion Neurons

Nearly 460 million individuals are affected by sensorineural hearing loss (SNHL), one of the most common human sensory disorders. In mammals, hearing loss is permanent due to the lack of efficient regenerative capacity of the sensory epithelia and spiral ganglion neurons (SGN). Sphere-forming progenitor cells can be isolated from the mammalian inner ear and give rise to inner ear specific cell types in vitro. However, the self-renewing capacities of auditory progenitor cells from the sensory and neuronal compartment are limited to few passages, even after adding powerful growth factor cocktails. Here, we provide phenotypical and functional characterization of a new pool of auditory progenitors as sustainable source for sphere-derived auditory neurons. The so-called phoenix auditory neuroprogenitors, isolated from the A/J mouse spiral ganglion, exhibit robust intrinsic self-renewal properties beyond 40 passages. At any passage or freezing–thawing cycle, phoenix spheres can be efficiently differentiated into mature spiral ganglion cells by withdrawing growth factors. The differentiated cells express both neuronal and glial cell phenotypic markers and exhibit similar functional properties as mouse spiral ganglion primary explants and human sphere-derived spiral ganglion cells. In contrast to other rodent models aiming at sustained production of auditory neurons, no genetic transformation of the progenitors is needed. Phoenix spheres therefore represent an interesting starting point to further investigate self-renewal in the mammalian inner ear, which is still far from any clinical application. In the meantime, phoenix spheres already offer an unlimited source of mammalian auditory neurons for high-throughput screens while substantially reducing the numbers of animals needed.

Substance P inhibits potassium and calcium currents in inner ear spiral ganglion neurons

2004 ◽  
Vol 1012 (1-2) ◽  
pp. 82-92 ◽  
Author(s):  
Wei Sun ◽  
Da-Lian Ding ◽  
Ping Wang ◽  
Jianhe Sun ◽  
Xiaojie Jin ◽  
...  
Keyword(s):  
Substance P ◽  
Inner Ear ◽  
Spiral Ganglion ◽  
Calcium Currents ◽  
Spiral Ganglion Neurons ◽  
Ganglion Neurons

scholarly journals Generation of a Spiral Ganglion Neuron Degeneration Mouse Model

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhengqing Hu ◽  
Fnu Komal ◽  
Aditi Singh ◽  
Meng Deng
Keyword(s):  
Inner Ear ◽  
Mouse Strain ◽  
Diphtheria Toxin ◽  
Damage Model ◽  
Spiral Ganglion ◽  
Functional Study ◽  
Spiral Ganglion Neuron ◽  
Mouse Strains ◽  
Brainstem Response ◽  
Ganglion Neurons

Spiral ganglion neurons (SGNs) can be injured by a wide variety of insults. However, there still is a lack of degeneration models to specifically damage the SGNs without disturbing other types of cells in the inner ear. This study aims to generate an SGN-specific damage model using the Cre-LoxP transgenic mouse strains. The Cre-inducible diphtheria toxin receptor (iDTR+/+) knock-in mouse strain was crossed with a mouse strain with Cre activity specific to neurons (NeflCreER/CreER). Expression of the Cre-recombinase activity was evaluated using the reporter mouse strain Ai9 at pre-hearing, hearing onset, and post-hearing stages. Accordingly, heterozygous NeflCreER/+;iDTR+/– mice were treated with tamoxifen on postnatal days 1–5 (P1–5), followed by diphtheria toxin (DT) or vehicle injection on P7, P14, and P21 to evaluate the SGN loss. Robust tamoxifen-induced Cre-mediated Ai9 tdTomato fluorescence was observed in the SGN area of heterozygous NeflCreER/+;Ai9+/– mice treated with tamoxifen, whereas vehicle-treated heterozygote mice did not show tdTomato fluorescence. Compared to vehicle-treated NeflCreER/+;iDTR+/– mice, DT-treated NeflCreER/+;iDTR+/– mice showed significant auditory brainstem response (ABR) threshold shifts and SGN cell loss. Hair cell count and functional study did not show significant changes. These results demonstrate that the NeflCreER/CreER mouse strain exhibits inducible SGN-specific Cre activity in the inner ear, which may serve as a valuable SGN damage model for regeneration research of the inner ear.

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