Nerves and hydrogen peroxide: how old enemies become new friends

ROS and nerves play together during the regeneration process: For many years, the role of reactive oxygen species (ROS) in neurobiology has mainly focused on its pathological implications in neurodegenerative diseases. Contrasting with this view, ROS were recently put forward as key positive signals for axon growth and repair, highlighting beneficial functions of ROS signalling in the vertebrate adult brain (Borquez et al., 2016). Nerve injury is often associated with damage of the neighbouring tissues. It was demonstrated, first in larvae and then in adult vertebrates, that the increase of ROS production induced by tissue lesion stimulates axon growth (Rieger and Sagasti, 2011; Gauron et al., 2013; Meda et al., 2016). Tissue re-innervation, starting with axon regeneration, is a prerequisite to launch the regenerative program in damaged tissues and organs (Kumar and Brockes, 2012). As ROS are also required for regeneration to proceed (Gauron et al., 2013), simultaneous control of tissue and axon regeneration by a same redox signal would be a parsimonious way to coordinate the reformation of a fully functional tissue (Meda et al., 2016) (Figure 1).