@article{DombertSivadasanSimonetal.2014,
  author    = {Dombert, Benjamin and Sivadasan, Rajeeve and Simon, Christian M. and Jablonka, Sibylle and Sendtner, Michael},
  title     = {Presynaptic Localization of Smn and hnRNP R in Axon Terminals of Embryonic and Postnatal Mouse Motoneurons},
  doi       = {10.1371/journal.pone.0110846},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-113655},
  year      = {2014},
  abstract  = {Spinal muscular atrophy (SMA) is caused by deficiency of the ubiquitously expressed survival motoneuron (SMN) protein. SMN is crucial component of a complex for the assembly of spliceosomal small nuclear ribonucleoprotein (snRNP) particles. Other cellular functions of SMN are less characterized so far. SMA predominantly affects lower motoneurons, but the cellular basis for this relative specificity is still unknown. In contrast to nonneuronal cells where the protein is mainly localized in perinuclear regions and the nucleus, Smn is also present in dendrites, axons and axonal growth cones of isolated motoneurons in vitro. However, this distribution has not been shown in vivo and it is not clear whether Smn and hnRNP R are also present in presynaptic axon terminals of motoneurons in postnatal mice. Smn also associates with components not included in the classical SMN complex like RNA-binding proteins FUS, TDP43, HuD and hnRNP R which are involved in RNA processing, subcellular localization and translation. We show here that Smn and hnRNP R are present in presynaptic compartments at neuromuscular endplates of embryonic and postnatal mice. Smn and hnRNP R are localized in close proximity to each other in axons and axon terminals both in vitro and in vivo. We also provide new evidence for a direct interaction of Smn and hnRNP R in vitro and in vivo, particularly in the cytosol of motoneurons. These data point to functions of SMN beyond snRNP assembly which could be crucial for recruitment and transport of RNA particles into axons and axon terminals, a mechanism which may contribute to SMA pathogenesis.},
  language  = {en}
}
@article{SimonRauskolbGunnersenetal.2015,
  author    = {Simon, Christian M. and Rauskolb, Stefanie and Gunnersen, Jennifer M. and Holtmann, Bettina and Drepper, Carsten and Dombert, Benjamin and Braga, Massimiliano and Wiese, Stefan and Jablonka, Sibylle and P{\"u}hringer, Dirk and Zielasek, J{\"u}rgen and Hoeflich, Andreas and Silani, Vincenzo and Wolf, Eckhard and Kneitz, Susanne and Sommer, Claudia and Toyka, Klaus V. and Sendtner, Michael},
  title     = {Dysregulated IGFBP5 expression causes axon degeneration and motoneuron loss in diabetic neuropathy},
  series = {Acta Neuropathologica},
  volume    = {130},
  journal   = {Acta Neuropathologica},
  doi       = {10.1007/s00401-015-1446-8},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-154569},
  pages     = {373 -- 387},
  year      = {2015},
  abstract  = {Diabetic neuropathy (DNP), afflicting sensory and motor nerve fibers, is a major complication in diabetes.The underlying cellular mechanisms of axon degeneration are poorly understood. IGFBP5, an inhibitory binding protein for insulin-like growth factor 1 (IGF1) is highly up-regulated in nerve biopsies of patients with DNP. We investigated the pathogenic relevance of this finding in transgenic mice overexpressing IGFBP5 in motor axons and sensory nerve fibers. These mice develop motor axonopathy and sensory deficits similar to those seen in DNP. Motor axon degeneration was also observed in mice in which the IGF1 receptor(IGF1R) was conditionally depleted in motoneurons, indicating that reduced activity of IGF1 on IGF1R in motoneurons is responsible for the observed effect. These data provide evidence that elevated expression of IGFBP5 in diabetic nerves reduces the availability of IGF1 for IGF1R on motor axons, thus leading to progressive neurodegeneration. Inhibition of IGFBP5 could thus offer novel treatment strategies for DNP.},
  language  = {en}
}