A/Professor Massimo Hilliard
Queensland Brain Institute, University of Queensland
Title: Axonal fusion: an alternative mechanism to repair injured axons
Understanding the molecular mechanisms regulating axonal regeneration is essential for the development of effective therapies for nerve injuries. Despite a substantial knowledge being gained into how axonal re-growth is initiated, our understanding of the mechanisms needed to achieve target reconnection remains very poor. We and others have shown that precise reconnection of severed axons can occur in C. elegans and in other species through a process of axonal fusion, whereby the proximal regrowing fragment recognises and re-establishes membrane and cytoplasmic continuity with its own separated distal fragment, preventing it from undergoing degeneration. This represents a highly innovative and efficient way to re-establish connection between an injured neuron and its target tissue.
We have now characterised the axonal fusion process at the molecular level, and uncovered a critical role for molecules previously shown to mediate the recognition of apoptotic cells by neighbouring phagocytes. We propose that the processes of recognition between two separated regenerating axonal fragments and recognition between an apoptotic cell and phagocytes share molecular components and mechanisms.