@article{KriegerMetzgerJablonka2014,
  author    = {Krieger, Frank and Metzger, Friedrich and Jablonka, Sibylle},
  title     = {Differentiation defects in primary motoneurons from a SMARD1 mouse model that are insensitive to treatment with low dose PEGylated IGF1},
  series = {Rare Diseases},
  volume    = {2},
  journal   = {Rare Diseases},
  number    = {e29415},
  issn      = {2167-5511},
  doi       = {10.4161/rdis.29415},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-120610},
  year      = {2014},
  abstract  = {Muscle atrophy and diaphragmatic palsy are the clinical characteristics of spinal muscular atrophy with respiratory distress type 1 (SMARD1), and are well represented in the neuromuscular degeneration \((Nmd^{2J})\) mouse, modeling the juvenile form of SMARD1. Both in humans and mice mutations in the IGHMBP2 gene lead to motoneuron degeneration. We could previously demonstrate that treatment with a polyethylene glycol-coupled variant of IGF1 (PEG-IGF1) improves motor functions accompanied by reduced fiber degeneration in the gastrocnemius muscle and the diaphragm, but has no beneficial effect on motoneuron survival. These data raised the question which cell autonomous disease mechanisms contribute to dysfunction and loss of Ighmbp2-deficient motoneurons. An analysis of primary Ighmbp2-deficient motoneurons exhibited differentiation deficits such as reduced spontaneous \(Ca^{2+}\) transients and altered axon elongation, which was not compensated by PEG-IGF1. This points to an IGF1 independent mechanism of motoneuron degeneration that deserves treatment approaches in addition to IGF1.},
  language  = {en}
}
@article{PfeifferGuglielmiDombertJablonkaetal.2014,
  author    = {Pfeiffer-Guglielmi, Brigitte and Dombert, Benjamin and Jablonka, Sibylle and Hausherr, Vanessa and van Thriel, Christoph and Schobel, Nicole and Jansen, Ralf-Peter},
  title     = {Axonal and dendritic localization of mRNAs for glycogen-metabolizing enzymes in cultured rodent neurons},
  series = {BMC Neuroscience},
  volume    = {15},
  journal   = {BMC Neuroscience},
  number    = {70},
  issn      = {1471-2202},
  doi       = {10.1186/1471-2202-15-70},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-116049},
  year      = {2014},
  abstract  = {Background: Localization of mRNAs encoding cytoskeletal or signaling proteins to neuronal processes is known to contribute to axon growth, synaptic differentiation and plasticity. In addition, a still increasing spectrum of mRNAs has been demonstrated to be localized under different conditions and developing stages thus reflecting a highly regulated mechanism and a role of mRNA localization in a broad range of cellular processes. Results: Applying fluorescence in-situ-hybridization with specific riboprobes on cultured neurons and nervous tissue sections, we investigated whether the mRNAs for two metabolic enzymes, namely glycogen synthase (GS) and glycogen phosphorylase (GP), the key enzymes of glycogen metabolism, may also be targeted to neuronal processes. If it were so, this might contribute to clarify the so far enigmatic role of neuronal glycogen. We found that the mRNAs for both enzymes are localized to axonal and dendritic processes in cultured lumbar spinal motoneurons, but not in cultured trigeminal neurons. In cultured cortical neurons which do not store glycogen but nevertheless express glycogen synthase, the GS mRNA is also subject to axonal and dendritic localization. In spinal motoneurons and trigeminal neurons in situ, however, the mRNAs could only be demonstrated in the neuronal somata but not in the nerves. Conclusions: We could demonstrate that the mRNAs for major enzymes of neural energy metabolism can be localized to neuronal processes. The heterogeneous pattern of mRNA localization in different culture types and developmental stages stresses that mRNA localization is a versatile mechanism for the fine-tuning of cellular events. Our findings suggest that mRNA localization for enzymes of glycogen metabolism could allow adaptation to spatial and temporal energy demands in neuronal events like growth, repair and synaptic transmission.},
  language  = {en}
}
@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}
}