13
views
0
recommends
+1 Recommend
0 collections
    0
    shares
      • Record: found
      • Abstract: not found
      • Article: not found

      Aminoglycoside- and Cisplatin-Induced Ototoxicity: Mechanisms and Otoprotective Strategies

      ,
      Cold Spring Harbor Perspectives in Medicine
      Cold Spring Harbor Laboratory

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Ototoxicity refers to damage of inner ear structures (i.e., the cochlea and vestibule) and their function (hearing and balance) following exposure to specific in-hospital medications (i.e., aminoglycoside antibiotics, platinum-based drugs), as well as a variety of environmental or occupational exposures (e.g., metals and solvents). This review provides a narrative derived from relevant papers describing factors contributing to (or increasing the risk of) aminoglycoside and cisplatin-induced ototoxicity. We also review current strategies to protect against ototoxicity induced by these indispensable pharmacotherapeutic treatments for life-threatening infections and solid tumors. We end by highlighting several interventional strategies that are currently in development, as well as the diverse challenges that still need to be overcome to prevent drug-induced hearing loss.

          Related collections

          Most cited references139

          • Record: found
          • Abstract: found
          • Article: not found

          X-ray structure of a calcium-activated TMEM16 lipid scramblase.

          The TMEM16 family of proteins, also known as anoctamins, features a remarkable functional diversity. This family contains the long sought-after Ca(2+)-activated chloride channels as well as lipid scramblases and cation channels. Here we present the crystal structure of a TMEM16 family member from the fungus Nectria haematococca that operates as a Ca(2+)-activated lipid scramblase. Each subunit of the homodimeric protein contains ten transmembrane helices and a hydrophilic membrane-traversing cavity that is exposed to the lipid bilayer as a potential site of catalysis. This cavity harbours a conserved Ca(2+)-binding site located within the hydrophobic core of the membrane. Mutations of residues involved in Ca(2+) coordination affect both lipid scrambling in N. haematococca TMEM16 and ion conduction in the Cl(-) channel TMEM16A. The structure reveals the general architecture of the family and its mode of Ca(2+) activation. It also provides insight into potential scrambling mechanisms and serves as a framework to unravel the conduction of ions in certain TMEM16 proteins.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            FM1-43 dye behaves as a permeant blocker of the hair-cell mechanotransducer channel.

            Hair cells in mouse cochlear cultures are selectively labeled by brief exposure to FM1-43, a styryl dye used to study endocytosis and exocytosis. Real-time confocal microscopy indicates that dye entry is rapid and via the apical surface. Cooling to 4 degrees C and high extracellular calcium both reduce dye loading. Pretreatment with EGTA, a condition that breaks tip links and prevents mechanotransducer channel gating, abolishes subsequent dye loading in the presence of calcium. Dye loading recovers after calcium chelation with a time course similar to that described for tip-link regeneration. Myo7a mutant hair cells, which can transduce but have all mechanotransducer channels normally closed at rest, do not label with FM1-43 unless the bundles are stimulated by large excitatory stimuli. Extracellular perfusion of FM1-43 reversibly blocks mechanotransduction with half-blocking concentrations in the low micromolar range. The block is reduced by high extracellular calcium and is voltage dependent, decreasing at extreme positive and negative potentials, indicating that FM1-43 behaves as a permeant blocker of the mechanotransducer channel. The time course for the relief of block after voltage steps to extreme potentials further suggests that FM1-43 competes with other cations for binding sites within the pore of the channel. FM1-43 does not block the transducer channel from the intracellular side at concentrations that would cause complete block when applied extracellularly. Calcium chelation and FM1-43 both reduce the ototoxic effects of the aminoglycoside antibiotic neomycin sulfate, suggesting that FM1-43 and aminoglycosides enter hair cells via the same pathway.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              Nociceptor and hair cell transducer properties of TRPA1, a channel for pain and hearing.

              Mechanosensory channels of sensory cells mediate the sensations of hearing, touch, and some forms of pain. The TRPA1 (a member of the TRP family of ion channel proteins) channel is activated by pain-producing chemicals, and its inhibition impairs hair cell mechanotransduction. As shown here and previously, TRPA1 is expressed by hair cells as well as by most nociceptors (small neurons of dorsal root, trigeminal, and nodose ganglia) and localizes to their sensory terminals (mechanosensory stereocilia and peripheral free nerves, respectively). Thus, TRPA1 channels are proposed to mediate transduction in both hair cells and nociceptors. Accordingly, we find that heterologously expressed TRPA1 display channel behaviors expected for both auditory and nociceptive transducers. First, TRPA1 and the hair cell transducer share a unique set of pore properties not described for any other channel (block by gadolinium, amiloride, gentamicin, and ruthenium red, a ranging conductance of approximately 100 pS that is reduced to 54% by calcium, permeating calcium-induced potentiation followed by closure, and reopening by depolarization), supporting a direct role of TRPA1 as a pore-forming subunit of the hair cell transducer. Second, TRPA1 channels inactivate in hyperpolarized cells but remain open in depolarized cells. This property provides a mechanism for the lack of desensitization, coincidence detection, and allodynia that characterize pain by allowing a sensory neuron to respond constantly to sustained stimulation that is suprathreshold (i.e., noxious) and yet permitting the same cell to ignore sustained stimulation that is subthreshold (i.e., innocuous). Our results support a TRPA1 role in both nociceptor and hair cell transduction.
                Bookmark

                Author and article information

                Journal
                Cold Spring Harbor Perspectives in Medicine
                Cold Spring Harb Perspect Med
                Cold Spring Harbor Laboratory
                2157-1422
                November 01 2019
                November 2019
                November 2019
                December 17 2018
                : 9
                : 11
                : a033548
                Article
                10.1101/cshperspect.a033548
                6579718
                30559254
                413a6c25-00ae-450e-b79b-3af72adf1676
                © 2018
                History

                Comments

                Comment on this article