Research Fellows Directory
Simona Parrinello Elliott
Dr Simona Parrinello Elliott
Imperial College London
I study the biology of the peripheral nerves, which are the nerves that connect the brain to limbs and organs. In contrast to the central nervous system (brain and spinal cord), the nerves of the peripheral nervous system are capable of repairing themselves after injury. Nerves are mainly made up of neurons and Schwann cells. The former are electrically excitable cells with long projections, which they use to transmit the impulses necessary for movement and sensation. The latter are specialized cells that wrap around and insulate the neurons to help in the transmission of impulses. After a nerve is cut, the neuronal projections below the lesion die, but over time new projections start to regrow back and eventually reconnect to their target organs. Schwann cells play a major role in the repair process in that they temporarily lose their specialized function and divide to make new nerve tissue and to guide the re-growth of the neurons. Once the neurons reach their targets, Schwann cells stop dividing and respecialize to insulate the newly reformed nerve and reestablish nerve function. In some pathologies Schwann cells are found in a permanent “injured state” in which they divide abnormally (nerve tumours) and/or do not function properly (neurodegenerative disease). Therefore, studying the molecular and cellular mechanisms that control Schwann cell behaviour after injury is key to understanding both nerve repair and disease and has been the focus of my most recent work.
In humans, nerve repair after severe injuries that result in extensive tissue loss is not very efficient; such lesions represent a major problem in peripheral neurosurgery. Our research, by unravelling the normal mechanisms that mediate repair in milder injuries, has the potential to uncover new therapeutic approaches for the improvement of nerve repair after severe ones. Moreover, it might provide insights into nerve pathologies in which Schwann cells become fixed in a “permanently injured state”.