@article{DombertBalkLueningschroeretal.2017,
  author    = {Dombert, Benjamin and Balk, Stefanie and L{\"u}ningschr{\"o}r, Patrick and Moradi, Mehri and Sivadasan, Rajeeve and Saal-Bauernschubert, Lena and Jablonka, Sibylle},
  title     = {BDNF/trkB induction of calcium transients through Ca\(_{v}\)2.2 calcium channels in motoneurons corresponds to F-actin assembly and growth cone formation on β2-chain laminin (221)},
  series = {Frontiers in Molecular Neuroscience},
  volume    = {10},
  journal   = {Frontiers in Molecular Neuroscience},
  number    = {346},
  doi       = {10.3389/fnmol.2017.00346},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-159094},
  year      = {2017},
  abstract  = {Spontaneous Ca\(^{2+}\) transients and actin dynamics in primary motoneurons correspond to cellular differentiation such as axon elongation and growth cone formation. Brain-derived neurotrophic factor (BDNF) and its receptor trkB support both motoneuron survival and synaptic differentiation. However, in motoneurons effects of BDNF/trkB signaling on spontaneous Ca\(^{2+}\) influx and actin dynamics at axonal growth cones are not fully unraveled. In our study we addressed the question how neurotrophic factor signaling corresponds to cell autonomous excitability and growth cone formation. Primary motoneurons from mouse embryos were cultured on the synapse specific, β2-chain containing laminin isoform (221) regulating axon elongation through spontaneous Ca\(^{2+}\) transients that are in turn induced by enhanced clustering of N-type specific voltage-gated Ca\(^{2+}\) channels (Ca\(_{v}\)2.2) in axonal growth cones. TrkB-deficient (trkBTK\(^{-/-}\)) mouse motoneurons which express no full-length trkB receptor and wildtype motoneurons cultured without BDNF exhibited reduced spontaneous Ca\(^{2+}\) transients that corresponded to altered axon elongation and defects in growth cone morphology which was accompanied by changes in the local actin cytoskeleton. Vice versa, the acute application of BDNF resulted in the induction of spontaneous Ca\(^{2+}\) transients and Ca\(_{v}\)2.2 clustering in motor growth cones, as well as the activation of trkB downstream signaling cascades which promoted the stabilization of β-actin via the LIM kinase pathway and phosphorylation of profilin at Tyr129. Finally, we identified a mutual regulation of neuronal excitability and actin dynamics in axonal growth cones of embryonic motoneurons cultured on laminin-221/211. Impaired excitability resulted in dysregulated axon extension and local actin cytoskeleton, whereas upon β-actin knockdown Ca\(_{v}\)2.2 clustering was affected. We conclude from our data that in embryonic motoneurons BDNF/trkB signaling contributes to axon elongation and growth cone formation through changes in the local actin cytoskeleton accompanied by increased Ca\(_{v}\)2.2 clustering and local calcium transients. These findings may help to explore cellular mechanisms which might be dysregulated during maturation of embryonic motoneurons leading to motoneuron disease.},
  language  = {en}
}
@article{LueningschroerBinottiDombertetal.2017,
  author    = {L{\"u}ningschr{\"o}r, Patrick and Binotti, Beyenech and Dombert, Benjamin and Heimann, Peter and Perez-Lara, Angel and Slotta, Carsten and Thau-Habermann, Nadine and von Collenberg, Cora R. and Karl, Franziska and Damme, Markus and Horowitz, Arie and Maystadt, Isabelle and F{\"u}chtbauer, Annette and F{\"u}chtbauer, Ernst-Martin and Jablonka, Sibylle and Blum, Robert and {\"U}{\c{c}}eyler, Nurcan and Petri, Susanne and Kaltschmidt, Barbara and Jahn, Reinhard and Kaltschmidt, Christian and Sendtner, Michael},
  title     = {Plekhg5-regulated autophagy of synaptic vesicles reveals a pathogenic mechanism in motoneuron disease},
  series = {Nature Communications},
  volume    = {8},
  journal   = {Nature Communications},
  number    = {678},
  doi       = {10.1038/s41467-017-00689-z},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-170048},
  year      = {2017},
  abstract  = {Autophagy-mediated degradation of synaptic components maintains synaptic homeostasis but also constitutes a mechanism of neurodegeneration. It is unclear how autophagy of synaptic vesicles and components of presynaptic active zones is regulated. Here, we show that Pleckstrin homology containing family member 5 (Plekhg5) modulates autophagy of synaptic vesicles in axon terminals of motoneurons via its function as a guanine exchange factor for Rab26, a small GTPase that specifically directs synaptic vesicles to preautophagosomal structures. Plekhg5 gene inactivation in mice results in a late-onset motoneuron disease, characterized by degeneration of axon terminals. Plekhg5-depleted cultured motoneurons show defective axon growth and impaired autophagy of synaptic vesicles, which can be rescued by constitutively active Rab26. These findings define a mechanism for regulating autophagy in neurons that specifically targets synaptic vesicles. Disruption of this mechanism may contribute to the pathophysiology of several forms of motoneuron disease.},
  language  = {en}
}