Traumatic injury to CNS fiber tracts--what are the genes telling us?

In contrast to the peripheral nervous system (PNS) nerve fiber tracts of the adult central nervous system (CNS) cannot spontaneously regenerate in response to lesions. As a result injured individuals suffer from chronically impaired neuronal connections leading to major motor-, sensory- and cognitive deficits. It is generally assumed that combinatorial effects account for this regeneration failure including a growth non-permissive environment within CNS lesion zones as well as incomplete activation of axonal growth programmes. In order to design CNS repair strategies it is, therefore, imperative to address the molecular mechanisms responsible for this abortive growth behaviour by means of large scale screening techniques. This review summarizes the outcome of recent gene expression profiling studies investigating local and remote molecular reactions following CNS axotomy.