Ronald Jeroen Pasterkamp

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This study evaluates the expression of the chemorepellent semaphorin III (D)/collapsin-1 (sema III) following lesions to the rat CNS. Scar tissue, formed after penetrating injuries to the lateral olfactory tract (LOT), cortex, perforant pathway, and spinal cord, contained numerous spindle-shaped cells expressing high levels of sema III mRNA. The properties(More)
In this study we evaluate the expression of all members of the class 3 semaphorins and their receptor components following complete transection and contusion lesions of the adult rat spinal cord. Following both types of lesions the expression of all class 3 semaphorins is induced in fibroblast in the neural scar. The distribution of semaphorin-positive(More)
We have investigated the hypothesis that the chemorepellent Semaphorin3A may be involved in the failure of axonal regeneration after injury to the ascending dorsal columns of adult rats. Following transection of the thoracic dorsal columns, fibroblasts in the dorsolateral parts of the lesion site showed robust expression of Semaphorin3A mRNA. In addition,(More)
Progressive axon outgrowth during neural development contrasts with the failure of regenerative neurite growth in the mature mammalian central nervous system (CNS). During neuroembryogenesis, spatiotemporal patterns of repellent and attractant activities in the vicinity of the growth cone favor neurite outgrowth. In the mature CNS, however, a relative(More)
The competence of neurons to regenerate depends on their ability to initiate a program of gene expression supporting growth and on the growth-permissive properties of glial cells in the distal stump of the injured nerve. Most studies on intrinsic molecular mechanisms governing peripheral nerve regeneration have focussed on the lesion-induced expression of(More)
The mammalian olfactory system is capable of discriminating among a large variety of odor molecules and is therefore essential for the identification of food, enemies and mating partners. The assembly and maintenance of olfactory connectivity have been shown to depend on the combinatorial actions of a variety of molecular signals, including extracellular(More)
Alterations in neuronal connectivity of the mature central nervous system (CNS) appear to depend on a delicate balance between growth-promoting and growth-inhibiting molecules. To begin to address a potential role of the secreted chemorepulsive protein semaphorin(D)III/collapsin-1 (semaIII/coll-1) in structural plasticity during adulthood, we used(More)
A dominant feature of neural circuitry is the organization of neuronal projections and synapses into specific brain nuclei or laminae. Lamina-specific connectivity is controlled by the selective expression of extracellular guidance and adhesion molecules in the target field. However, how (sub)nucleus-specific connections are established and whether(More)
Rett syndrome (RTT) is an autism spectrum disorder that results from mutations in the transcriptional regulator methyl-CpG binding protein 2 (MECP2). In the present work, we demonstrate that MeCP2 deficiency disrupts the establishment of neural connections before synaptogenesis. Using both in vitro and in vivo approaches, we identify dynamic alterations in(More)