Lens regeneration

Abstract

Lens regeneration after complete lens removal (lentectomy) has mainly been studied in amphibians. Adult newts or axolotl larvae regenerate the lens from the iris while frog tadpoles from the cornea. Transdifferentiation is the term used to describe the cellular and molecular events that underlie lens regeneration, which involves a terminally differentiated tissue (iris) to change and give rise to a different differentiated tissue (lens). This chapter starts with general comparisons among the three amphibians competent for lens regeneration focusing on how these animals have been used as models to study the process. We focus on newt lens regeneration as it can provide a more broad understanding of the process. We concentrate on current knowledge about the mechanism of lens regeneration by presenting the classical histological stages together with molecular signatures that accompany each stage. We address questions regarding the nature of the contributing cells and their relationship to stem cells. We conclude by presenting high-throughput data including the first newt transcriptome and its application during newt lens regeneration. All this information obtained from lower vertebrates is essential for translation research in higher vertebrates where lens regeneration does not occur.