Temporal dynamics of neurite outgrowth promoted by basic fibroblast growth factor in chick ciliary ganglia

Abstract

Basic fibroblast growth factor (bFGF) is a potent and multifunctional neurotrophic factor that can influence neuronal survival and differentiation. It has been shown to modulate growth and orientation of neuritic processes both in intact organs and in neuronal cultures, with a wide spectrum of effects on different preparations. Here we report that it promotes neurite growth in developing parasympathetic neurons from the chick ciliary ganglion. We have used both organotypic cultures and dissociated neurons, and we have combined assessment of global neurite growth by immunocytochemical techniques with evaluation of dynamic parameters of single neurites via time-lapse microscopy. We show that laminin, a molecule of the extracellular matrix that has been associated with stimulation of neurite extension, has only a limited and short-lived effect on neurite outgrowth. In contrast, bFGF can promote global growth of the neuritic network both in whole ganglia and in dissociated cultures for times up to 48 hr, and this effect is related to an increase in the growth rate of single neurites. Moreover, the effect can be observed even in enriched neuronal cultures, pointing to a direct action of bFGF on neurons.

The application of magnets directs the orientation of neurite outgrowth in cultured human neuronal cells

“…The formation of neuronal processes has been reported to be influenced by several trophic factors, such as nerve growth factor (Lakshmi and Joshi, 2006;Liu et al, 2007), brainderived neurotrophic factor (BDNF) in the rat ganglion (Lin et al, 2006), insulin-like growth factor-I (Shiraishi et al, 2006), retinoic acid (So et al, 2006), basic fibroblast growth factor (Zamburlin et al, 2006), and vascular endothelial growth factor in cerebral cortical neurons (Jin et al, 2006). These processes can regenerate when damaged, and the direction in which these process regenerate may be affected by the local environmental factors (Szpara et al, 2007;Vogelezang et al, 2007).…”

Calcium signals induced by FGF-2 in parasympathetic neurons: Role of second messenger pathways

“…In a well established model of peripheral neurons, cultured E7/E8 embryonic chick ciliary ganglion neurons, we have previously shown that FGF-2 can promote neuronal survival [4] and neurite outgrowth [25] in dissociated and organotypic cultures. Moreover, it induces long lasting changes in [Ca 2+ ] i through a mechanism mainly dependent on calcium influx from the extracellular medium [4].…”

A quantitative approach to the dynamics of neurite sprouting induced by a neurotrophic factor

“…In particular, it is known (supplementary material of Zamburlin et al, 2006;Arimura and Kaibuchi, 2007), that while new neurites can appear others can be retracted; therefore as a general model of neurite formation, we use a birth and death process (Goel and Rychter-Dyn, 1974) where birth corresponds to the formation of a neurite and death to its retraction. According to this process in the time interval ıt the probabilities of transition for birth and death are, respectively, k ıt = Prob(k → k + 1) and k ıt = Prob(k → k − 1); the master equation governing the process is then given, in differential form, by Goel and Rychter-Dyn (1974) …”

“…This function is of great relevance in the establishment of the correct connections between the individual components of the nervous system. Basic Fibroblast Growth Factor (bFGF) is one of the most extensively studied neurotrophic factors in this context (Abe and Saito, 2001), and it has been shown to exert different roles according to the specific experimental model: in many sensory and autonomic neurons it acts by promoting neurite growth (Perron and Bixby, 1999;Webber et al, 2005;Zamburlin et al, 2006), while in central neurons it has been shown to inhibit axonal growth (Catapano et al, 2004) or induce growth cone arrest and formation of branches and collaterals (Szebenyi et al, 2001). An equally relevant, although less studied, aspect is the role of the neurotrophic factor in the definition of the neuronal morphology, e.g.…”

“…This dynamic process, particularly in early phases, can consist of different components: sprouting and growth of neurites, but also their collapse and retraction, that ends with stabilization and specialization as dendrites and axon. In a well established model of developing peripheral nerve cells, embryonic chick cilary ganglion (CG) neurons, we have previously shown that bFGF can promote neurite growth, from both dissociated neurons and organotypic cultures (Zamburlin et al, 2006), pointing to two different features: the global growth of the whole neuritic mass, and the fact that this growth is ascribable, at least in part, to the production of longer neurites, dependent on the greater growth velocity of individual processes. The enhancement of growth can be observed on dissociated neurons after a few hours in culture: in the first 6-7 h the velocity of growth of individual neurites with bFGF added to the external medium is not significantly different from that occurring when neurons are maintained in its absence, i.e.…”