Go to JCI Insight
  • About
  • Editors
  • Consulting Editors
  • For authors
  • Alerts
  • Advertising/recruitment
  • Subscribe
  • Contact
  • Current Issue
  • Past Issues
  • By specialty
    • Cardiology
    • Gastroenterology
    • Immunology
    • Metabolism
    • Nephrology
    • Neuroscience
    • Oncology
    • Pulmonology
    • Vascular biology
    • All...
  • Videos
    • Conversations with Giants in Medicine
    • Author's Takes
  • Reviews
    • View all reviews...
    • Mechanisms Underlying the Metabolic Syndrome (Oct 2019)
    • Reparative Immunology (Jul 2019)
    • Allergy (Apr 2019)
    • Biology of familial cancer predisposition syndromes (Feb 2019)
    • Mitochondrial dysfunction in disease (Aug 2018)
    • Lipid mediators of disease (Jul 2018)
    • Cellular senescence in human disease (Apr 2018)
    • View all review series...
  • Collections
    • Recently published
    • In-Press Preview
    • Commentaries
    • Concise Communication
    • Editorials
    • Viewpoint
    • Scientific Show Stoppers
    • Top read articles
  • Clinical Medicine
  • JCI This Month
    • Current issue
    • Past issues

  • About
  • Editors
  • Consulting Editors
  • For authors
  • Current issue
  • Past issues
  • By specialty
  • Subscribe
  • Alerts
  • Advertise
  • Contact
  • Conversations with Giants in Medicine
  • Author's Takes
  • Recently published
  • Brief Reports
  • Technical Advances
  • Commentaries
  • Editorials
  • Hindsight
  • Review series
  • Reviews
  • The Attending Physician
  • First Author Perspectives
  • Scientific Show Stoppers
  • Top read articles
  • Concise Communication

Otology

  • 7 Articles
  • 1 Posts
Deletion of Tmtc4 activates the unfolded protein response causing postnatal hearing loss
Jiang Li, … , Dylan K. Chan, Elliott H. Sherr
Jiang Li, … , Dylan K. Chan, Elliott H. Sherr
Published September 6, 2018
Citation Information: J Clin Invest. 2018. https://doi.org/10.1172/JCI97498.
View: Text | PDF

Deletion of Tmtc4 activates the unfolded protein response causing postnatal hearing loss

  • Text
  • PDF
Abstract

Hearing loss is a significant public health concern, affecting over 250 million people worldwide. Both genetic and environmental etiologies are linked to hearing loss, but in many cases the underlying cellular pathophysiology is not well understood, highlighting the importance of further discovery. We found that inactivation of the gene, Tmtc4 (transmembrane and tetratricopeptide repeat 4), which was broadly expressed in the mouse cochlea, caused acquired hearing loss in mice. Our data showed Tmtc4 enriched in the endoplasmic reticulum, and that it functioned by regulating Ca2+ dynamics and the unfolded protein response (UPR). Given this genetic linkage of the UPR to hearing loss, we demonstrated a direct link between the more common noise-induced hearing loss (NIHL) and the UPR. These experiments suggested a novel approach to treatment. We demonstrated that the small-molecule UPR and stress response modulator ISRIB (Integrated Stress Response Inhibitor), which activates eIF2B, prevented NIHL in a mouse model. Moreover, in an inverse genetic complementation approach, we demonstrated that mice with homozygous inactivation of both Tmtc4 and Chop had less hearing loss than knockout of Tmtc4 alone. This study implicated a novel mechanism for hearing impairment, highlighting a potential treatment approach for a broad range of human hearing-loss disorders.

Authors

Jiang Li, Omar Akil, Stephanie L. Rouse, Conor W. McLaughlin, Ian R. Matthews, Lawrence R. Lustig, Dylan K. Chan, Elliott H. Sherr

×

Modifier variant of METTL13 suppresses human GAB1-associated profound deafness
Rizwan Yousaf, … , Thomas B. Friedman, Saima Riazuddin
Rizwan Yousaf, … , Thomas B. Friedman, Saima Riazuddin
Published February 6, 2018
Citation Information: J Clin Invest. 2018. https://doi.org/10.1172/JCI97350.
View: Text | PDF

Modifier variant of METTL13 suppresses human GAB1-associated profound deafness

  • Text
  • PDF
Abstract

A modifier variant can abrogate risk of a monogenic disorder. DFNM1 is a locus on chromosome 1 encoding a dominant suppressor of human DFNB26 recessive, profound deafness. Here, we report that DFNB26 is associated with a substitution (p.Gly116Glu) in the pleckstrin-homology-domain of GAB1, an essential scaffold in the MET/HGF pathway. A dominant substitution (p.Arg544Gln) of METTL13, encoding a predicted methyltransferase, is the DFNM1 suppressor of GAB1-associated deafness. In zebrafish, human METTL13 mRNA harboring the modifier allele rescues the GAB1 associated morphant phenotype. In mouse, GAB1 and METTL13 co-localize in auditory sensory neurons, and METTL13 co-immunoprecipitates with GAB1 and SPRY2, indicating at least a tripartite complex. Expression of MET-signaling genes in human lymphoblastoid cells of individuals homozygous for p.Gly116Glu GAB1 revealed dysregulation of HGF, MET, SHP2, and SPRY2, all of which have reported variants associated with deafness. However, SPRY2 was not dysregulated in normal-hearing humans homozygous for both the GAB1 DFNB26 deafness variant and the dominant METTL13 deafness suppressor, indicating a plausible mechanism of suppression. Identification of METTL13-based modification of MET-signaling provides potential therapeutic strategy for a wide range of associated hearing disorders. Furthermore, MET-signaling is essential for diverse functions in many tissues including the inner ear. Therefore, identification of the modifier of MET-signaling is likely to have broad clinical implications.

Authors

Rizwan Yousaf, Zubair M. Ahmed, Arnaud P.J. Giese, Robert J. Morell, Ayala Lagziel, Alain Dabdoub, Edward R. Wilcox, Sheikh Riazuddin, Thomas B. Friedman, Saima Riazuddin

×

Mitochondrial calcium uptake underlies ROS generation during aminoglycoside-induced hair cell death
Robert Esterberg, … , Edwin W. Rubel, David W. Raible
Robert Esterberg, … , Edwin W. Rubel, David W. Raible
Published August 8, 2016
Citation Information: J Clin Invest. 2016. https://doi.org/10.1172/JCI84939.
View: Text | PDF

Mitochondrial calcium uptake underlies ROS generation during aminoglycoside-induced hair cell death

  • Text
  • PDF
Abstract

Exposure to aminoglycoside antibiotics can lead to the generation of toxic levels of reactive oxygen species (ROS) within mechanosensory hair cells of the inner ear that have been implicated in hearing and balance disorders. Better understanding of the origin of aminoglycoside-induced ROS could focus the development of therapies aimed at preventing this event. In this work, we used the zebrafish lateral line system to monitor the dynamic behavior of mitochondrial and cytoplasmic oxidation occurring within the same dying hair cell following exposure to aminoglycosides. The increased oxidation observed in both mitochondria and cytoplasm of dying hair cells was highly correlated with mitochondrial calcium uptake. Application of the mitochondrial uniporter inhibitor Ru360 reduced mitochondrial and cytoplasmic oxidation, suggesting that mitochondrial calcium drives ROS generation during aminoglycoside-induced hair cell death. Furthermore, targeting mitochondria with free radical scavengers conferred superior protection against aminoglycoside exposure compared with identical, untargeted scavengers. Our findings suggest that targeted therapies aimed at preventing mitochondrial oxidation have therapeutic potential to ameliorate the toxic effects of aminoglycoside exposure.

Authors

Robert Esterberg, Tor Linbo, Sarah B. Pickett, Patricia Wu, Henry C. Ou, Edwin W. Rubel, David W. Raible

×

Designer aminoglycosides prevent cochlear hair cell loss and hearing loss
Markus E. Huth, … , Alan G. Cheng, Anthony J. Ricci
Markus E. Huth, … , Alan G. Cheng, Anthony J. Ricci
Published January 2, 2015
Citation Information: J Clin Invest. 2015. https://doi.org/10.1172/JCI77424.
View: Text | PDF

Designer aminoglycosides prevent cochlear hair cell loss and hearing loss

  • Text
  • PDF
Abstract

Bacterial infections represent a rapidly growing challenge to human health. Aminoglycosides are widely used broad-spectrum antibiotics, but they inflict permanent hearing loss in up to ~50% of patients by causing selective sensory hair cell loss. Here, we hypothesized that reducing aminoglycoside entry into hair cells via mechanotransducer channels would reduce ototoxicity, and therefore we synthesized 9 aminoglycosides with modifications based on biophysical properties of the hair cell mechanotransducer channel and interactions between aminoglycosides and the bacterial ribosome. Compared with the parent aminoglycoside sisomicin, all 9 derivatives displayed no or reduced ototoxicity, with the lead compound N1MS 17 times less ototoxic and with reduced penetration of hair cell mechanotransducer channels in rat cochlear cultures. Both N1MS and sisomicin suppressed growth of E. coli and K. pneumoniae, with N1MS exhibiting superior activity against extended spectrum β lactamase producers, despite diminished activity against P. aeruginosa and S. aureus. Moreover, systemic sisomicin treatment of mice resulted in 75% to 85% hair cell loss and profound hearing loss, whereas N1MS treatment preserved both hair cells and hearing. Finally, in mice with E. coli–infected bladders, systemic N1MS treatment eliminated bacteria from urinary tract tissues and serially collected urine samples, without compromising auditory and kidney functions. Together, our findings establish N1MS as a nonototoxic aminoglycoside and support targeted modification as a promising approach to generating nonototoxic antibiotics.

Authors

Markus E. Huth, Kyu-Hee Han, Kayvon Sotoudeh, Yi-Ju Hsieh, Thomas Effertz, Andrew A. Vu, Sarah Verhoeven, Michael H. Hsieh, Robert Greenhouse, Alan G. Cheng, Anthony J. Ricci

×

Optogenetic stimulation of the auditory pathway
Victor H. Hernandez, … , Nicola Strenzke, Tobias Moser
Victor H. Hernandez, … , Nicola Strenzke, Tobias Moser
Published February 10, 2014
Citation Information: J Clin Invest. 2014. https://doi.org/10.1172/JCI69050.
View: Text | PDF

Optogenetic stimulation of the auditory pathway

  • Text
  • PDF
Abstract

Auditory prostheses can partially restore speech comprehension when hearing fails. Sound coding with current prostheses is based on electrical stimulation of auditory neurons and has limited frequency resolution due to broad current spread within the cochlea. In contrast, optical stimulation can be spatially confined, which may improve frequency resolution. Here, we used animal models to characterize optogenetic stimulation, which is the optical stimulation of neurons genetically engineered to express the light-gated ion channel channelrhodopsin-2 (ChR2). Optogenetic stimulation of spiral ganglion neurons (SGNs) activated the auditory pathway, as demonstrated by recordings of single neuron and neuronal population responses. Furthermore, optogenetic stimulation of SGNs restored auditory activity in deaf mice. Approximation of the spatial spread of cochlear excitation by recording local field potentials (LFPs) in the inferior colliculus in response to suprathreshold optical, acoustic, and electrical stimuli indicated that optogenetic stimulation achieves better frequency resolution than monopolar electrical stimulation. Virus-mediated expression of a ChR2 variant with greater light sensitivity in SGNs reduced the amount of light required for responses and allowed neuronal spiking following stimulation up to 60 Hz. Our study demonstrates a strategy for optogenetic stimulation of the auditory pathway in rodents and lays the groundwork for future applications of cochlear optogenetics in auditory research and prosthetics.

Authors

Victor H. Hernandez, Anna Gehrt, Kirsten Reuter, Zhizi Jing, Marcus Jeschke, Alejandro Mendoza Schulz, Gerhard Hoch, Matthias Bartels, Gerhard Vogt, Carolyn W. Garnham, Hiromu Yawo, Yugo Fukazawa, George J. Augustine, Ernst Bamberg, Sebastian Kügler, Tim Salditt, Livia de Hoz, Nicola Strenzke, Tobias Moser

×

Sound preconditioning therapy inhibits ototoxic hearing loss in mice
Soumen Roy, … , Tracy S. Fitzgerald, Lisa L. Cunningham
Soumen Roy, … , Tracy S. Fitzgerald, Lisa L. Cunningham
Published October 15, 2013
Citation Information: J Clin Invest. 2013. https://doi.org/10.1172/JCI71353.
View: Text | PDF | Erratum

Sound preconditioning therapy inhibits ototoxic hearing loss in mice

  • Text
  • PDF
Abstract

Therapeutic drugs with ototoxic side effects cause significant hearing loss for thousands of patients annually. Two major classes of ototoxic drugs are cisplatin and the aminoglycoside antibiotics, both of which are toxic to mechanosensory hair cells, the receptor cells of the inner ear. A critical need exists for therapies that protect the inner ear without inhibiting the therapeutic efficacy of these drugs. The induction of heat shock proteins (HSPs) inhibits both aminoglycoside- and cisplatin-induced hair cell death and hearing loss. We hypothesized that exposure to sound that is titrated to stress the inner ear without causing permanent damage would induce HSPs in the cochlea and inhibit ototoxic drug–induced hearing loss. We developed a sound exposure protocol that induces HSPs without causing permanent hearing loss. We used this protocol in conjunction with a newly developed mouse model of cisplatin ototoxicity and found that preconditioning mouse inner ears with sound has a robust protective effect against cisplatin-induced hearing loss and hair cell death. Sound therapy also provided protection against aminoglycoside-induced hearing loss. These data indicate that sound preconditioning protects against both classes of ototoxic drugs, and they suggest that sound therapy holds promise for preventing hearing loss in patients receiving these drugs.

Authors

Soumen Roy, Matthew M. Ryals, Astrid Botty Van den Bruele, Tracy S. Fitzgerald, Lisa L. Cunningham

×

Mouse model of enlarged vestibular aqueducts defines temporal requirement of Slc26a4 expression for hearing acquisition
Byung Yoon Choi, … , Thomas B. Friedman, Andrew J. Griffith
Byung Yoon Choi, … , Thomas B. Friedman, Andrew J. Griffith
Published October 3, 2011
Citation Information: J Clin Invest. 2011. https://doi.org/10.1172/JCI59353.
View: Text | PDF

Mouse model of enlarged vestibular aqueducts defines temporal requirement of Slc26a4 expression for hearing acquisition

  • Text
  • PDF
Abstract

Mutations in human SLC26A4 are a common cause of hearing loss associated with enlarged vestibular aqueducts (EVA). SLC26A4 encodes pendrin, an anion-base exchanger expressed in inner ear epithelial cells that secretes HCO3– into endolymph. Studies of Slc26a4-null mice indicate that pendrin is essential for inner ear development, but have not revealed whether pendrin is specifically necessary for homeostasis. Slc26a4-null mice are profoundly deaf, with severe inner ear malformations and degenerative changes that do not model the less severe human phenotype. Here, we describe studies in which we generated a binary transgenic mouse line in which Slc26a4 expression could be induced with doxycycline. The transgenes were crossed onto the Slc26a4-null background so that all functional pendrin was derived from the transgenes. Varying the temporal expression of Slc26a4 revealed that E16.5 to P2 was the critical interval in which pendrin was required for acquisition of normal hearing. Lack of pendrin during this period led to endolymphatic acidification, loss of the endocochlear potential, and failure to acquire normal hearing. Doxycycline initiation at E18.5 or discontinuation at E17.5 resulted in partial hearing loss approximating the human EVA auditory phenotype. These data collectively provide mechanistic insight into hearing loss caused by SLC26A4 mutations and establish a model for further studies of EVA-associated hearing loss.

Authors

Byung Yoon Choi, Hyoung-Mi Kim, Taku Ito, Kyu-Yup Lee, Xiangming Li, Kelly Monahan, Yaqing Wen, Elizabeth Wilson, Kiyoto Kurima, Thomas L. Saunders, Ronald S. Petralia, Philine Wangemann, Thomas B. Friedman, Andrew J. Griffith

×
New First Author Perspective: Markus Huth
“First Author Perspectives” provide insight into the research process underlying a recently published manuscript.
Published January 6, 2015
Otology
Advertisement
Follow JCI:
Copyright © 2019 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)

Sign up for email alerts