Sensing through Non-Sensing Ocular Ion Channels

Int J Mol Sci. 2020 Sep 21;21(18):6925. doi: 10.3390/ijms21186925.

Abstract

Ion channels are membrane-spanning integral proteins expressed in multiple organs, including the eye. In the eye, ion channels are involved in various physiological processes, like signal transmission and visual processing. A wide range of mutations have been reported in the corresponding genes and their interacting subunit coding genes, which contribute significantly to an array of blindness, termed ocular channelopathies. These mutations result in either a loss- or gain-of channel functions affecting the structure, assembly, trafficking, and localization of channel proteins. A dominant-negative effect is caused in a few channels formed by the assembly of several subunits that exist as homo- or heteromeric proteins. Here, we review the role of different mutations in switching a "sensing" ion channel to "non-sensing," leading to ocular channelopathies like Leber's congenital amaurosis 16 (LCA16), cone dystrophy, congenital stationary night blindness (CSNB), achromatopsia, bestrophinopathies, retinitis pigmentosa, etc. We also discuss the various in vitro and in vivo disease models available to investigate the impact of mutations on channel properties, to dissect the disease mechanism, and understand the pathophysiology. Innovating the potential pharmacological and therapeutic approaches and their efficient delivery to the eye for reversing a "non-sensing" channel to "sensing" would be life-changing.

Keywords: CRISPR-DNA/RNA editing; anticodon engineered tRNA; disease models; inherited channelopathy; nonsense mutation therapies; ocular ion channels; readthrough.

Publication types

  • Review

MeSH terms

  • Animals
  • Channelopathies* / genetics
  • Channelopathies* / metabolism
  • Channelopathies* / pathology
  • Channelopathies* / therapy
  • Disease Models, Animal
  • Eye Diseases, Hereditary* / genetics
  • Eye Diseases, Hereditary* / metabolism
  • Eye Diseases, Hereditary* / pathology
  • Eye Diseases, Hereditary* / therapy
  • Genetic Diseases, X-Linked* / genetics
  • Genetic Diseases, X-Linked* / metabolism
  • Genetic Diseases, X-Linked* / pathology
  • Genetic Diseases, X-Linked* / therapy
  • Humans
  • Ion Channels* / genetics
  • Ion Channels* / metabolism
  • Leber Congenital Amaurosis* / genetics
  • Leber Congenital Amaurosis* / metabolism
  • Leber Congenital Amaurosis* / pathology
  • Leber Congenital Amaurosis* / therapy
  • Myopia* / genetics
  • Myopia* / metabolism
  • Myopia* / pathology
  • Myopia* / therapy
  • Night Blindness* / genetics
  • Night Blindness* / metabolism
  • Night Blindness* / pathology
  • Night Blindness* / therapy
  • Retinitis Pigmentosa* / genetics
  • Retinitis Pigmentosa* / metabolism
  • Retinitis Pigmentosa* / pathology
  • Retinitis Pigmentosa* / therapy

Substances

  • Ion Channels

Supplementary concepts

  • Night blindness, congenital stationary