University of Groningen
Molecular composition and function of the spiral ganglion neuron peripheral synapse in mice
Reijntjes, Daniël Onne Jilt
DOI:
10.33612/diss.93524048
IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below.
Document Version
Publisher's PDF, also known as Version of record
Publication date: 2019
Link to publication in University of Groningen/UMCG research database
Citation for published version (APA):
Reijntjes, D. O. J. (2019). Molecular composition and function of the spiral ganglion neuron peripheral synapse in mice. University of Groningen. https://doi.org/10.33612/diss.93524048
Copyright
Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).
Take-down policy
If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.
Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum.
Molecular composition and
function of the spiral ganglion
neuron peripheral synapse in mice
Experiments for this thesis were performed in collaboration with the university of Groningen, the University Medical Center Groningen, and the BCN graduate school.
This research was supported by the Heinsius-Houbolt fund and the foundation for the hearing impaired child.
© D.O.J. Reijntjes, Groningen 2019. All rights reserved. No part of this thesis may be reproduced without prior permission of the author and the publishers holding copy-rights of the published articles.
Cover design: D.O.J. Reijntjes Layout: D.O.J. Reijntjes
Printed by: Gildprint - www.gildeprint.nl ISBN printed version: 978-94-034-1702-8 ISBN electronic version: 978-94-034-1701-1
Molecular composition and
function of the spiral
ganglion neuron peripheral
synapse in mice
PhD thesis
to obtain the degree of PhD at the
University of Groningen
on the authority of the
Rector Magnificus prof. C. Wijmenga
and in accordance with
the decision by the College of Deans.
This thesis will be defended in public on
Monday 9 September 2019 at 11.00 hours
by
Daniël Onne Jilt Reijntjes
born on the 10
thof June 1990
in Groningen
Supervisor
Prof. P. van Dijk
Co-supervisor
Dr. S. J. Pyott
Assessment Committee
Prof. J. C. Billeter
Prof. J. M. J. Kremer
Prof. K. P. Steel
Table of contents
1 Introduction
Preface . . . 2
1.1. The perception of sound . . . 3
1.2. Anatomy of the auditory system . . . 4
1.2.1. The peripheral auditory system . . . 5
1.2.2. The sensory hair cells . . . 8
1.2.3. The spiral ganglion neurons . . . 12
1.2.4. The central auditory system . . . 13
1.3. Acquired hearing loss . . . 16
1.4. Molecular composition and function of the spiral ganglion neuron peripheral synapse . . . 18
1.5. This thesis . . . 18
2 The afferent signaling complex 21 2.1. Overview . . . 22
2.2. Glutamate receptors and the postsynaptic density . . . 24
2.2.1. AMPA receptors . . . 24
2.2.2. Kainate receptors . . . 25
2.2.3. NMDA receptors . . . 26
2.2.4. Metabotropic glutamate receptors . . . 29
2.2.5. The postsynaptic density . . . 30
2.3. Glutamate uptake by neighboring supporting cells . . . 31
2.4. Voltage-gated ion channels and ion transporters . . . 32
2.4.1. Voltage-gated sodium channels . . . 32
2.4.2. Voltage-gated potassium channels . . . 34
2.4.3. HCN channels . . . 36
2.4.4. Other voltage-gated ion channels and ion transporters . . . 36
2.5. Lateral efferent innervation of the type I spiral ganglion neurons . . . 38
2.5.1. Acetylcholine . . . 39
2.5.2. Dopamine . . . 40
2.5.3. GABA . . . 42
2.6. The afferent signaling complex . . . 45
2.6.1. Glutamatergic signalling . . . 45
2.6.2. Voltage-gated ion channels . . . 49
2.7. Conclusion . . . 51
3 KN a1channels shape peripheral auditory function 53 Abstract . . . 54
3.1. Introduction . . . 54
3.2. Materials & Methods . . . 56
3.2.1. Animals . . . 56
3.2.2. RNA isolation and sequence analysis . . . 56
3.2.3. Single molecule fluorescence in situ hybridization (smFISH) with RNAscope . . . 57
3.2.4. Measurement of auditory brainstem responses . . . 58
3.2.5. Histological assessment of the cochlear morphology . . . 59
3.2.6. Immunofluorescence, confocal microscopy and image analysis of isolated auditory sensory epithelia . . . 59
3.2.7. Patch clamp electrophysiology of isolated spiral ganglion neurons . . . 60
3.3. Results . . . 61
3.3.1. SLO channel transcripts encoding KN a1channels are expressed in the intact sensorineural structures and specifically spiral gan-glion neurons . . . 61
3.3.2. KN a1DKO mice have normal ABR thresholds but reduced wave I amplitudes . . . 64
3.3.3. Cochlear morphology, spiral ganglion cell density, and architec-ture of the afferent synapses are normal in KN a1DKO mice . . 68
3.3.4. Spiral ganglion neurons isolated from KN a1 DKO mice do not have Na+-sensitive outward K+ currents and display altered action potential waveforms . . . 71
3.4. Discussion . . . 76
4 Acquired hearing loss in KN a1knockout mice 81 Abstract . . . 82
4.1. Introduction . . . 82
4.2. Materials & Methods . . . 83
4.2.1. Animals . . . 84
4.2.2. Auditory brainstem responses . . . 84
4.2.3. Noise exposure . . . 84
4.2.4. Inner ear dissection and immunohistochemistry . . . 85
4.2.5. Image acquisition and analysis . . . 85
4.2.6. Statistics . . . 85
4.3. Results . . . 86
4.3.1. ABR wave I threshold responses in ageing KN a1DKO mice . . . 86
4.3.2. Outer hair cell survival in ageing mice . . . 86
4.3.3. ABR wave I amplitude slopes in ageing KN a1DKO mice . . . 87
4.3.4. ABR wave I latency slopes in ageing KN a1DKO mice . . . 90
4.3.5. Inner hair cell-spiral ganglion neuron synapse survival in KN a1 DKO mice . . . 90
4.3.6. ABR wave I threshold responses in KN a1DKO mice after noise
exposure . . . 91
4.3.7. Wave I amplitude slopes in KN a1DKO mice after noise exposure 93 4.3.8. Wave I latency slopes in KN a1 DKO and WT mice after noise exposure . . . 95
4.3.9. Synapse survival in KN a1DKO mice after noise exposure . . . . 96
4.4. Discussion . . . 97
4.4.1. Development of age-related and noise-induced hearing loss in KN a1DKO mice . . . 97
4.4.2. Mechanisms underlying increased vulnerability of KN a1 DKO mice to development of age-related hearing loss and noise-induced hearing loss . . . 100
5 Volume gradients of synaptic proteins 103 Abstract . . . 104
5.1. Introduction . . . 104
5.2. Materials & Methods . . . 107
5.2.1. Animals . . . 107
5.2.2. Immunohistochemistry . . . 107
5.2.3. Image acquisition and processing . . . 109
5.2.4. Volume quantification of pre- and postsynaptic proteins . . . 109
5.2.5. Data transformation and pillar-modiolar classification of synapses110 5.2.6. Statistics . . . 111
5.3. Results . . . 111
5.3.1. Pillar- and modiolar volume gradients in CBA/CaJ mice . . . 111
5.3.2. Volume gradients at the level of individual synapses in CBA/CaJ mice . . . 113
5.3.3. Pillar- and modiolar volume gradients in C57BL/6, and FVB/NJ mice . . . 115
5.3.4. Volume gradients at the synaptic level in C57BL/6 and FVB/NJ mice . . . 117
5.3.5. Volume gradients in postsynaptic density proteins in C57BL/6, and FVB/NJ mice . . . 117
5.3.6. Volume gradients in postsynaptic density proteins at the synap-tic level in C57BL/6, and FVB/NJ mice . . . 119
5.4. Discussion . . . 121
5.4.1. Opposing vs. concurrent synaptic volume gradients in mice . . . 122
5.4.2. Opposing vs. concurrent synaptic volume gradients in mammals 124 5.4.3. Implications . . . 125
6 General discussion 125 6.1. Molecular architecture and molecular processes of the SGN . . . 126
6.2. Novel protein expression and function . . . 126
6.3. Spiral ganglion neuron subgroup detection . . . 129
6.4. Conclusions . . . 130
7. Summary 135
8. Nederlandse samenvatting 136
9. Acknowledgements 139
10. Cited references 141
