Differential Cytoskeletal Changes during Growth Cone Collapse in Response to hSema III and Thrombin

Fritsche, Jens; Reber, Bernhard F. X.; Schindelholz, Benno; Bandtlow, Christine E.

doi:10.1006/mcne.1999.0777

Cited by 44 publications

(32 citation statements)

References 130 publications

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“…The effects of inhibitory factors such as Sema3A on the cytoskeleton have been more difficult to characterize because their effects lead to growth cone collapse (Fan et al, 1993;Fritsche et al, 1999;Fournier et al, 2000;Aizawa et al, 2001). In the present study, we cultured cortical neurons on a highly adhesive substrate, poly-D-lysine, which prevented growth cone collapse that occurs on laminin, a less adhesive substrate, and allowed us to visualize dynamic changes in the cytoskeleton after application of Sema3A.…”

Section: Cytoskeletal Reorganization In Response To Guidance Cuesmentioning

confidence: 99%

Netrin-1 and Semaphorin 3A Promote or Inhibit Cortical Axon Branching, Respectively, by Reorganization of the Cytoskeleton

Dent¹,

Barnes²,

Tang³

et al. 2004

J. Neurosci.

261

233

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In many CNS pathways, target innervation occurs by axon branching rather than extension of the primary growth cone into targets. To investigate mechanisms of branch formation, we studied the effects of attractive and inhibitory guidance cues on cortical axon branching. We found that netrin-1, which attracts cortical axons, and FGF-2 increased branching by Ͼ50%, whereas semaphorin 3A (Sema3A), which repels cortical axons, inhibited branching by 50%. Importantly, none of the factors affected axon length significantly. The increase in branching by FGF-2 and the inhibition of branching by Sema3A were mediated by opposing effects on the growth cone (expansion vs collapse) and on the cytoskeleton. FGF-2 increased actin polymerization and formation of microtubule loops in growth cones over many hours, whereas Sema3A depolymerized actin filaments, attenuated microtubule dynamics, and collapsed microtubule arrays within minutes. Netrin-1 promoted rapid axon branching, often without involving the growth cone. Branches formed de novo on the axon shaft within 30 min after local application of netrin-1, which induced rapid accumulation of actin filaments in filopodia. Importantly, increased actin polymerization and microtubule dynamics were necessary for axon branching to occur. Taken together, these results show that guidance factors influence the organization and dynamics of the cytoskeleton at the growth cone and the axon shaft to promote or inhibit axon branching. Independent of axon outgrowth, axon branching in response to guidance cues can occur over different time courses by different cellular mechanisms.

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Section: Cytoskeletal Reorganization In Response To Guidance Cuesmentioning

confidence: 99%

Netrin-1 and Semaphorin 3A Promote or Inhibit Cortical Axon Branching, Respectively, by Reorganization of the Cytoskeleton

Dent¹,

Barnes²,

Tang³

et al. 2004

J. Neurosci.

261

233

View full text Add to dashboard Cite

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“…The Sema 3A response involves multiple mechanisms, including the disruption of the actin cytoskeletal and focal complexes (Fan et al, 1993;Fritsche et al, 1999;Woo and Gomez, 2006). Collapse of COS-7 cells coexpressing Plexin-A1 and NP-1 does not seem to involve contractile responses (Turner et al, 2004); however, retraction of DRG neurons does involve myosin II (Gallo, 2006).…”

Section: Drg Growth Cones Contain All Three Isoforms (Iia Iib and Imentioning

confidence: 99%

“…The Sema 3A-dependent repulsive response is associated with growth cone collapse and is known to involve the Rho family of small GTPases that act as molecular switches (Jin and Strittmatter, 1997;Kuhn et al, 1999;Turner et al, 2004) and their downstream effectors, the actin cytoskeleton and focal contacts (Fan et al, 1993;Fritsche et al, 1999;Woo and Gomez, 2006). However the pathways that are involved and their relationship to growth cone responses has not been fully characterized.…”

Section: Introductionmentioning

confidence: 99%

Dorsal Root Ganglion Neurons React to Semaphorin 3A Application through a Biphasic Response that Requires Multiple Myosin II Isoforms

Brown

Wysolmerski

Bridgman

2009

MBoC

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Growth cone responses to guidance cues provide the basis for neuronal pathfinding. Although many cues have been identified, less is known about how signals are translated into the cytoskeletal rearrangements that steer directional changes during pathfinding. Here we show that the response of dorsal root ganglion (DRG) neurons to Semaphorin 3A gradients can be divided into two steps: growth cone collapse and retraction. Collapse is inhibited by overexpression of myosin IIA or growth on high substrate-bound laminin-1. Inhibition of collapse also prevents retractions; however collapse can occur without retraction. Inhibition of myosin II activity with blebbistatin or by using neurons from myosin IIB knockouts inhibits retraction. Collapse is associated with movement of myosin IIA from the growth cone to the neurite. Myosin IIB redistributes from a broad distribution to the rear of the growth cone and neck of the connecting neurite. High substrate-bound laminin-1 prevents or reverses these changes. This suggests a model for the Sema 3A response that involves loss of growth cone myosin IIA to facilitate actin meshwork instability and collapse, followed by myosin IIB concentration at the rear of the cone and neck region where it associates with actin bundles to drive retraction. INTRODUCTIONCorrect responses to extracellular signaling molecules during development are essential for the formation of the mammalian central and peripheral nervous systems (Sobeih and Corfas, 2002;Hagg, 2005). Growth cones navigate through the tissue environment in vivo by integrating growth-promoting signals with guidance cue signals at choice points and then responding through two opposing processes: extension and retraction (Buettner, 1994;Dontchev and Letourneau, 2003). This steers the growing axon to the correct target location. Cues are classified as either attractive or repulsive depending on their ability to invoke responses. In vitro attractants generally stimulate growth and turning toward the source of the cue, whereas repulsive cues induce turning away from the cue (Lohof et al., 1992;Fan and Raper, 1995). Repulsive cues can also cause growth cone collapse and temporary cessation of outgrowth (Luo et al., 1993;Wahl et al., 2000). It is unclear to what degree full or partial collapse or even retractions are associated with growth cone steering in vivo (Knobel et al., 1999;Mason and Erskine, 2000;Kalil et al., 2000). The complex in vivo environment is likely to result in a variety of behaviors that reflect the integration of signals from multiple cues within a short time period. Some of these interactions occur at the receptor level (Stein and Tessier-Lavigne, 2001;Halloran and Wolman, 2006), but others may converge on common growth cone effector mechanisms. To understand growth cone behavior responsible for pathfinding in vivo, it is important to fully dissect the responses to individual cues in vitro.Sema 3A is secreted by cells in the developing spinal cord and repels dorsal root ganglion (DRG) neurons that are sensitive to nerv...

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“…These findings are consistent with the idea that depolymerization of actin filaments initiates neurite formation and extension and conversely that actin polymerization triggers neurite retraction. On the other hand, however, it has been reported that chemorepellent semaphorin 3A, which induces growth cone collapse and subsequent axonal growth arrest, induces actin depolymerization (58,59). Thus, at present it is controversial as to which type of actin cytoskeletal reorganization (depolymerization or polymerization) regulates which type of neurite remodeling (neurite formation or retraction).…”

Section: Pip-5kin-␣ Functions As a Downstream Effector For Rock In Ormentioning

confidence: 99%

Phosphatidylinositol 4-Phosphate 5-Kinase Is Essential for ROCK-mediated Neurite Remodeling

Yamazaki¹,

Miyazaki²,

Watanabe³

et al. 2002

Journal of Biological Chemistry

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Phosphatidylinositol 4-phosphate 5-kinase (PIP-5kin) regulates actin cytoskeletal reorganization through its product phosphatidylinositol 4,5-bisphosphate. In the present study we demonstrate that PIP-5kin is essential for neurite remodeling, which is regulated by actin cytoskeletal reorganization in neuroblastoma N1E-115 cells. Overexpression of wild-type mouse PIP-5kin-␣ inhibits the neurite formation that is normally stimulated by serum depletion, whereas a lipid kinase-defective mutant of PIP-5kin-␣, D266A, triggers neurite extension even in the presence of serum and blocks lysophosphatidic acid-induced neurite retraction. These results phenocopy those previously reported for the small GTPase RhoA and its effector p160 Rho-associated coiled coilforming protein kinase (ROCK). However, the ROCKspecific inhibitor Y-27632 failed to block the inhibition by PIP-5kin-␣ of neurite extension, whereas D266A did block the neurite retraction induced by overexpression of ROCK. These results, taken together, suggest that PIP-5kin-␣ functions as a downstream effector for RhoA/ ROCK to couple lysophosphatidic acid signaling to neurite retraction presumably through its product phosphatidylinositol 4,5-bisphosphate.Axon guidance is a critical event in the establishment of neuronal networks during embryogenesis and is regulated by extracellular cues such as chemoattractants and chemorepellents, which are recognized by growth cones at the tips of axons (1, 2). Axons extend toward chemoattractants and away from chemorepellents through mechanisms involving actin cytoskeletal reorganization in the growth cone (3, 4).Recently accumulated evidence suggests that the Rho family GTPases (Rho, Rac, and Cdc42) play crucial roles in reorganizing the actin cytoskeleton in neurons, thereby regulating the morphology of neurites and growth cones (5-8). In particular, Rho appears to be implicated in the repulsive signaling pathway. In mouse neuroblastoma N1E-115 cells, overexpression of a constitutively active mutant of Rho prevents neurite formation (9, 10), and inactivation of endogenous Rho by Clostridium botulinum C3 exoenzyme inhibits the growth cone collapse and neurite retraction induced by lysophosphatidic acid (LPA) 1 (9, 10). Inhibition of growth cone collapse by inactivation of Rho has also been shown for myelin-stimulated central nervous system neurons (11) and Ephrin-A5-stimulated retinal neurons (12).Rho-associated kinases termed ROCK, Rho-kinase, and ROK mediate Rho-induced actin cytoskeletal reorganization (13-15) and subsequent repulsive responses of neurites including growth cone collapse and neurite retraction. Evidence for this includes the findings that overexpression of ROCK as well as the active mutant of RhoA, RhoAV14, inhibits neurite formation in N1E-115 cells (16,17). In addition, pharmacological inactivation of endogenous ROCK, similar to inhibition of Rho activity, interferes with LPA-induced neurite retraction in N1E-115 cells (16,17) and Ephrin-A5-induced growth cone collapse in retinal neurons (12).Although the ...

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Differential Cytoskeletal Changes during Growth Cone Collapse in Response to hSema III and Thrombin

Cited by 44 publications

References 130 publications

Netrin-1 and Semaphorin 3A Promote or Inhibit Cortical Axon Branching, Respectively, by Reorganization of the Cytoskeleton

Netrin-1 and Semaphorin 3A Promote or Inhibit Cortical Axon Branching, Respectively, by Reorganization of the Cytoskeleton

Dorsal Root Ganglion Neurons React to Semaphorin 3A Application through a Biphasic Response that Requires Multiple Myosin II Isoforms

Phosphatidylinositol 4-Phosphate 5-Kinase Is Essential for ROCK-mediated Neurite Remodeling

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