Different modes of growth cone collapse in NG 108-15 cells

Abstract

In the fundamental process of neuronal path-finding, a growth cone at the tip of every neurite detects and follows multiple guidance cues regulating outgrowth and initiating directional changes. While the main focus of research lies on the cytoskeletal dynamics underlying growth cone advancement, we investigated collapse and retraction mechanisms in NG108-15 growth cones transiently transfected with mCherry-LifeAct and pCS2+/EMTB-3XGFP for filamentous actin and microtubules, respectively. Using fluorescence time lapse microscopy we could identify two distinct modes of growth cone collapse leading either to neurite retraction or to a controlled halt of neurite extension. In the latter case, lateral movement and folding of actin bundles (filopodia) confine microtubule extension and limit microtubule-based expansion processes without the necessity of a constantly engaged actin turnover machinery. We term this previously unreported second type fold collapse and suggest that it marks an intermediate-term mode of growth regulation closing the gap between full retraction and small scale fluctuations.Electronic supplementary materialThe online version of this article (doi:10.1007/s00249-013-0907-z) contains supplementary material, which is available to authorized users.

Cdc42 and RhoA reveal different spatio-temporal dynamics upon local stimulation with Semaphorin-3A

“…Local stimulation with Sema3A coated beads induced the formation of active Cdc42 waves that propagated from the edge of the GC to the center of the cell with a period of 70 s (Figure 7 ). The same active Cdc42 waves were found in spontaneous GC collapse and retraction in response to repellent signals naturally occurring in neuronal cell culture, but with a mean period of 110 s (Rauch et al, 2013 ). How differently Sema3A stimulation can influence Cdc42 wave behavior is still an open question.…”

“…NG108-15 neuroblastoma cells are a good model system for neuronal signaling and growth (Smalheiser, 1991a , b ; Goshima et al, 1993 ; Tsuji et al, 2011 ). In the absence of adherent or diffusive signaling gradients, NG108-15 cells exhibit both a complete collapse of the GC followed by a full or partial retraction of the neurite and the transient collapse of the GC structures (Rauch et al, 2013 ). Therefore, to measure the spontaneous activity of RhoA and Ccd42 in GCs, we transiently overexpressed in NG108-15 cells the intermolecular RhoA/Cdc42 probes based on FRET (Murakoshi et al, 2011 ).…”

Loop formation and self-fasciculation of cortical axon using photonic guidance at long working distance

“…Movie 6 shows the process of l-loop fabrication in optically-guided rat cortical axon using spatio-temporally varying laser spots. The I-loop case seems to resemble with the transient (type-II) GC collapse case 30 , where the axon did not retract in its length. Though the self-fasciculated axon did not advance at a rate as before, such an I-loop constructed by laser based, repulsive-guidance method raises fundamental physical questions.…”

ConFiG: Contextual Fibre Growth to generate realistic axonal packing for diffusion MRI simulation

“…In nature, axons grow following chemical cues in their environment through various mechanisms which either attract or repel fibres to guide their growth ( Dent et al., 2011 ; Lowery and Vactor, 2009 ; Mortimer et al., 2008 ; Polleux and Snider, 2010 ; Price et al., 2017 ; Rauch et al., 2013 ; Sakisaka and Takai, 2005 ). In an attempt to emulate real axonal growth, mechanisms motivated by the following guidance processes have been integrated into ConFiG: Chemoattraction – the process by which fibres are attracted to diffusible chemical cues in their environment ( Mortimer et al., 2008 ; Price et al., 2017 ).…”