Regenerating hair cells in the mammalian inner ear: defining conditions in the vestibular sensory epithelia.

Lead Research Organisation: University College London
Department Name: Ear Institute

Abstract

Balance dysfunction results in dizziness and vertigo. It is often disabling and is a significant contributor to falls in the elderly. Dizziness is the most common cause of visits to the GP amongst the elderly population. It is also prevalent amongst those with acquired deafness. One major factor underlying balance dysfunction is the loss of sensory ?hair? cells from the vestibular (balance) system in the inner ear. This study will assess the potential for regenerating hair cells in the vestibular system. Vestibular tissue taken from humans and from young and aged mice will be maintained in culture. A consortium of ENT surgeons across the UK will provide human vestibular tissue, normally discarded during surgery for acoustic neuromas (benign tumours of the auditory nerve). This presents a unique opportunity for direct experimental comparison of inner ear tissues of animals and humans. When hair cells die the supporting cells that surround each one close the lesions. There is some evidence that after loss of hair cells, supporting cells can sometimes convert into hair cells, to replace those lost. This project will compare the capacity to regenerate functional hair cells in these vestibular tissues after insertion of a gene, Atoh1, that is known to induce conversion of supporting cells into hair cells, when delivered to supporting cells by a non-virulent virus engineered to contain it. The project will also assess possibilities for inducing supporting cell conversion by pharmacological manipulation of a biochemical pathway that normally is active during development of the inner ear to regulate the differential fate of precursor cells as hair cells or supporting cells. There is also evidence that the vestibular system of mice contains a small population of stem cells from which hair cells can be generated. The project will examine whether such a population exists in the human vestibular sensory tissues, and if so whether such cells could provide an alternative source of replacement hair cells. Any successful hair cell replacement strategy, however, depends upon the supporting cells that remain after hair cell loss maintaining an environment that will support the survival of functional replacement hair cells. The project therefore will also identify the characteristics of the supporting cell population during recovery after hair cell loss to determine the conditions under which regeneration occurs. Defining the conditions for hair cell regeneration in the vestibular system will lead to clinical treatments for a wide-spread, disabling condition.

Technical Summary

Loss of sensory ?hair? cells from the vestibular sensory epithelia is a major cause of balance dysfunction, dizziness and vertigo. Dizziness is the most common reason for visits to the GP by elderly people and balance dysfunction is a significant risk factor for falls in the elderly. Loss of vestibular hair cells and balance dysfunction are also side-effects of some otherwise useful drugs such as aminoglycoside antibiotics. Recent work has shown possibilities for regenerating hair cells in the mammalian inner ear by inducing the direct non-mitotic conversion of supporting cells into hair cells. There is also evidence that a stem cell population, able to produce cells with hair cell like characteristics, exists in mammalian vestibular organs. In this project explant cultures of human vestibular tissues, supported by parallel experiments with tissues from mice of different ages, will be used to determine conditions necessary for regenerating functional hair cells by induced conversion of supporting cells, and whether a stem cell population, that could provide an alternative source of replacement hair cells, exists in the human vestibular system. A consortium of surgeons from 6 UK centres will provide human vestibular tissue obtained at operations for acoustic neuromas. The characteristics of supporting cells in the repaired epithelium following hair cell loss and with hair cell regeneration will be examined to determine whether they retain specialisations conducive to sustain differentiation and survival of functional replacement hair cells. The distribution of ion transport proteins will be explored. Gap junction-mediated intercellular communication pathways will be examined by dye transfer in slice preparations. The capacity of the repaired epithelium of humans and of mice to produce functional replacement hair cells of both vestibular types following viral-mediated transfection with the gene encoding Atoh1 will be determined. The physiological signatures of regenerated hair cells will be identified by patch clamping in slice preparations. The activity of the Notch-Delta lateral inhibition signalling pathway will also be examined in the repaired epithelium to assess whether inhibition of Notch activation provides an alternative means to induce phenotypic conversion of supporting cells. Published procedures for isolating stem-like cells from inner ear epithelia and nurturing their differentiation will also be applied to the human tissues. In addition to assessing the potential for replacing lost hair cells in the vestibular system, the project will provide a ?test bed? for defining conditions and procedures that might encourage hair cell regeneration in the auditory epithelium.

Publications

10 25 50
 
Description Industrial Research Project
Amount £300,000 (GBP)
Organisation Cochlear Ltd. 
Sector Private
Country Global
Start 04/2014 
End 06/2017
 
Description Pauline Ashley Award
Amount £30,000 (GBP)
Organisation Action on Hearing Loss 
Sector Charity/Non Profit
Country United Kingdom
Start 04/2014 
End 10/2014
 
Description Project grant
Amount £475,000 (GBP)
Funding ID BB/102123X/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 12/2011 
End 11/2014
 
Description Project grant
Amount £401,434 (GBP)
Funding ID BB/M00659X/1 
Organisation Biotechnology and Biological Sciences Research Council (BBSRC) 
Sector Public
Country United Kingdom
Start 04/2015 
End 03/2018
 
Description Research Grant
Amount £71,714 (GBP)
Funding ID R395/1114 
Organisation The Dunhill Medical Trust 
Sector Charity/Non Profit
Country United Kingdom
Start 02/2015 
End 05/2016
 
Title Human inner ear tissue 
Description A consortium of surgeons harvesting inner ear tissue, that is normally discarded during surgery to remaove acoustic neuromas represent a unique resource for obtaining viable inner ear tissues for experimental studies. 
Type Of Material Biological samples 
Year Produced 2013 
Provided To Others? Yes  
Impact The potential for studies of possibilities for regenerating hair cells in the human inner ear have attracted interest from pharmaceutical companies. 
 
Description Transcriptome analysis of human vestibular tissue 
Organisation Imperial College London
Department National Heart & Lung Institute (NHLI)
Country United Kingdom 
Sector Academic/University 
PI Contribution We have collected tissue and performed experiments aimed at regenerating hair cells. RNA has been extracted from the samples and passed to Prof Lovett's laboratory at Imperial College
Collaborator Contribution Prof Lovett, Professor of systems Biology at Imperial College has undertaken next generation sequencing of the samples we have supplied and performed the bioinformatics to provide lists of genes expressed in the samples of human vestibular tissue.
Impact Invited presentations at: Inner Ear Biology Workshop, Rome 2015 Gordon Research Conference, 2016 Poster presentation at 39th Annual Meeting of the Association for Research in Otolaryngology 2016; Abstract PS455, page 271: "Manipulation of the Human Vestibular Environment to Generate Hair Cells", Taylor R, Holt J, Lovett M, Filia, A, Forge A
Start Year 2012
 
Description Viral vectors for gene transfer to human vestibular tissue 
Organisation Harvard University
Department Harvard Medical School
Country United States 
Sector Academic/University 
PI Contribution We have performed experiments using viral vectors containing the Atoh1 gene supplied by Prof Holt at Harvard, to transduce cells in the human vestibular sensory epithelia. Also performed experiments to assess the efficiency of transduction of human vestibular cells with a new, synthetic viral vector developed by Prof Holt and his colleagues.
Collaborator Contribution Supplied viral vectors for our experiments, and for assessment of his newly developed viral vector
Impact Invited presentations at; Inner Ear Biology Workshop, 2015 Gordon Research Conference 2016 Poster presentation at the 30th Meeting of the Association for Research in Otolaryngology, 2016, Abstract PS 455, page 271 "Manipulation of of the Human Vestibular Environment to Generate Hair Cells" Taylor R, Holt J, Lovett M, Filia A, Forge A Publication: Landegger LD, Pan B, Askew C, Wassmer SJ, Gluck SD, Galvin A, Taylor R, Forge A, Stankovic KM, Holt JR, Vandenberghe LH.(2017). A synthetic AAV vector enables safe and efficient gene transfer to the mammalian inner ear. Nat Biotechnol. 2017 Feb 6. doi: 10.1038/nbt.3781. [Epub ahead of print]
Start Year 2010
 
Description Audacity 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Type Of Presentation Paper Presentation
Geographic Reach National
Primary Audience Health professionals
Results and Impact Invited article in first edition of the British Society for Audiology newsletter "Audacity"

None as yet
Year(s) Of Engagement Activity 2013
 
Description Audiological Technicians Group 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Health professionals
Results and Impact 50 members of the audiology ENT professionals from across the Midlands at regular professional meeting. Discussion on regenerative medicine and cochlear implants

Audience members acknowledged value to their dealing with deaf patients and their carers where questions concerning stem cells etc. arise
Year(s) Of Engagement Activity 2013
 
Description Audiology Course, Salamanca Spain 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact Introduction to pathology of the inner ear and possibilities for therapeutic interventions to ameliorate or prevent hairing loss or balance dysfunction, including possibilities and limitations of regenerative strategies
Year(s) Of Engagement Activity 2016
 
Description Blog for Action on Hearing Loss about recently published paper 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Participants in your research and patient groups
Results and Impact The blog was written for the Action on Hearing Loss newsletter which is available openly on the web, but is sent to Action on Hearing Loss supporters and researchers as well as clinician and health care workers within the specialty

The blog has been circulated via Twitter.
Year(s) Of Engagement Activity 2014
 
Description British Acoustic Neuroma Association 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Patients, carers and/or patient groups
Results and Impact An update on work involving the use of inner ear tissue from acoustic neuroma patients was given. There was much interest and offers to participate in the study.
Year(s) Of Engagement Activity 2015
 
Description British Association for Audiological Physicians 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach National
Primary Audience Health professionals
Results and Impact Update on regenerative medicine as applied to inner ear to leading national audiological physicians

Many questions concerning how science relates to their clinical practice and value of update fro dealing with patients and thier carers
Year(s) Of Engagement Activity 2013
 
Description Career day 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach Local
Primary Audience Postgraduate students
Results and Impact Discussion about how to develop a career in science

Further workshops to be established.
Year(s) Of Engagement Activity 2013
 
Description Ear Foundation 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach National
Primary Audience Health professionals
Results and Impact Audience composed of health care professionals involved in cochlear implant programme and parents of children who have received cochlear implants. Question concerning directions towards replacing implant with biological interventions

Many questions concerning the role and likelihood of regenerative therapies for deafness.
Year(s) Of Engagement Activity 2012
 
Description Interview for National news; Daily Telegraph August 18th 2018 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Dr Taylor was interviewed by a journalist from the Daily Telegraph concerning her work on regenerating sensory cell sin the inner ear tissue from humans, and its significance for therapies fro hearing and balance dysfunction particularly in the elderly. The report appeared the following day. Several letters from interested readers were subsequently received.
Year(s) Of Engagement Activity 2018
 
Description Interview with popular science journal "Wired" 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Interview with reporter from journal "Wired" concerning the impact of the paper published in Nature Biotechnology.
Year(s) Of Engagement Activity 2017
 
Description Invited presentation at Gordon Rearch Conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk presenting results from studies in our laboratory on possibilities for regeneration in the sensory epithelia of the vestibular (balance) system of the inner ear but also defining challenges and limitiations that face regenerative therapies for the hearing organ.
Year(s) Of Engagement Activity 2016
 
Description Invited talk at the College de France, May 2019: Perspectives on hair cell regeneration in the inner ears of vertebrates 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited talk at a sympoisium "Development and Regeneration" at the College de France, Paris May 2019. Symposium open to general public and recorded on video for general access. Symposium discussed regerative mechansims in different contexts and possible therapeutic potentials
Year(s) Of Engagement Activity 2019
 
Description Politzer Society Meeting -International conference for Clinicians 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Type Of Presentation Keynote/Invited Speaker
Geographic Reach International
Primary Audience Health professionals
Results and Impact About 50 ENT & skull base surgeons and Neuro-otologists attended for update in research in their specialty

Good feedback on necessity of undersatnding developments relating to their clinical practice. Numerous questions at end of presentation and informally afterwards.
Year(s) Of Engagement Activity 2011
 
Description RSM: Novel Interventions for the human cochlea 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact A meeting of the otology section of the Royal Society of Medicine to update clinicians on recent relevant research
Year(s) Of Engagement Activity 2015
 
Description Symposium on Hereditary Hearing Impairment; from diagnosis to therapy 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact The symposium was organised in Madrid as part of an educational series for mainly undergraduate and postgraduate students as well as post docs, clinicians and academics providing an insight into research into the genetics and pathology of the inner ear. Much discussion and interested questions
Year(s) Of Engagement Activity 2015
 
Description Talk to audiological scientists 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Professional Practitioners
Results and Impact About 40 people, clinicians, audiological scientists, audiologists as well as researchers attended and discussions on the possibilities for therapies for deafness and balance disorders followed.

The health care professionals acknowledges the value of the talk in relation to their ability to inform patients and their carers better about future prospects for treatments of their condition. It also stimulated acknowledgment of the importance of vestibular disorders as an under recognised health care issue, especially for the elderly population.
Year(s) Of Engagement Activity 2014