@article{AndreskaAufmkolkSaueretal.2014,
  author    = {Andreska, Thomas and Aufmkolk, Sarah and Sauer, Markus and Blum, Robert},
  title     = {High abundance of BDNF within glutamatergic presynapses of cultured hippocampal neurons},
  series = {Frontiers in Cellular Neuroscience},
  volume    = {8},
  journal   = {Frontiers in Cellular Neuroscience},
  number    = {107},
  issn      = {1662-5102},
  doi       = {10.3389/fncel.2014.00107},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119793},
  year      = {2014},
  abstract  = {In the mammalian brain, the neurotrophin brain-derived neurotrophic factor (BDNF) has emerged as a key factor for synaptic refinement, plasticity and learning. Although BDNF-induced signaling cascades are well known, the spatial aspects of the synaptic BDNF localization remained unclear. Recent data provide strong evidence for an exclusive presynaptic location and anterograde secretion of endogenous BDNF at synapses of the hippocampal circuit. In contrast, various studies using BDNF overexpression in cultured hippocampal neurons support the idea that postsynaptic elements and other dendritic structures are the preferential sites of BDNF localization and release. In this study we used rigorously tested anti-BDNF antibodies and achieved a dense labeling of endogenous BDNF close to synapses. Confocal microscopy showed natural BDNF close to many, but not all glutamatergic synapses, while neither GABAergic synapses nor postsynaptic structures carried a typical synaptic BDNF label. To visualize the BDNF distribution within the fine structure of synapses, we implemented super resolution fluorescence imaging by direct stochastic optical reconstruction microscopy (dSTORM). Two-color dSTORM images of neurites were acquired with a spatial resolution of ~20 nm. At this resolution, the synaptic scaffold proteins Bassoon and Homer exhibit hallmarks of mature synapses and form juxtaposed bars, separated by a synaptic cleft. BDNF imaging signals form granule-like clusters with a mean size of ~60 nm and are preferentially found within the fine structure of the glutamatergic presynapse. Individual glutamatergic presynapses carried up to 90\% of the synaptic BDNF immunoreactivity, and only a minor fraction of BDNF molecules was found close to the postsynaptic bars. Our data proof that hippocampal neurons are able to enrich and store high amounts of BDNF in small granules within the mature glutamatergic presynapse, at a principle site of synaptic plasticity.},
  language  = {en}
}
@article{AndreskaLueningschroerSendtner2020,
  author    = {Andreska, Thomas and L{\"u}ningschr{\"o}r, Patrick and Sendtner, Michael},
  title     = {Regulation of TrkB cell surface expression — a mechanism for modulation of neuronal responsiveness to brain-derived neurotrophic factor},
  series = {Cell and Tissue Research},
  volume    = {382},
  journal   = {Cell and Tissue Research},
  doi       = {10.1007/s00441-020-03224-7},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-235055},
  pages     = {5-14},
  year      = {2020},
  abstract  = {Neurotrophin signaling via receptor tyrosine kinases is essential for the development and function of the nervous system in vertebrates. TrkB activation and signaling show substantial differences to other receptor tyrosine kinases of the Trk family that mediate the responses to nerve growth factor and neurotrophin-3. Growing evidence suggests that TrkB cell surface expression is highly regulated and determines the sensitivity of neurons to brain-derived neurotrophic factor (BDNF). This translocation of TrkB depends on co-factors and modulators of cAMP levels, N-glycosylation, and receptor transactivation. This process can occur in very short time periods and the resulting rapid modulation of target cell sensitivity to BDNF could represent a mechanism for fine-tuning of synaptic plasticity and communication in complex neuronal networks. This review focuses on those modulatory mechanisms in neurons that regulate responsiveness to BDNF via control of TrkB surface expression.},
  language  = {en}
}