Working Group Ljaschenko

 

Dr. Dmitrij Ljaschenko
E-Mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Telefon: +49 (0)341 97 22 105
Telefax: +49 (0)341 97 22 109

 

Science

The fundamental task of neurosciences is to understand the processes by which humans and animals perceive the world, act, remember and learn. In our lab, we investigate the function of nervous systems on different levels. Focussing on the presynaptic side, we investigate mutations, which seem to cause neurodevelopmental deceases (NDD) in children. The Human Genetics Department of the University of Leipzig (Abou-Jamra lab) provide information on mutations of synaptic protein genes in young patients. To understand the pathological mechanisms of the NDDs, we replicate these mutations and analyse the synaptic function in Drosophila (cooperation with the Langenhan lab, RSI Biochemistry, Leipzig). Specifically, we focus on different single nucleotide polymorphisms (point mutations) of the UNC13C Gene.
On the postsynaptic level we study nicotinic acetylcholine receptors (nAChR), which are postsynaptic receptor ion-channels of the vertebrate neuromuscular junction. Using ultra-low noise single channel recordings, we measure openings and closings of this channel at an extremely high temporal resolution. We reliably detect open and shut times as short as 5 µs and analyse thousands of them to deduce quantitative kinetic models of the nAChR (cooperation with the Heckmann lab, Physiology Department, Würzburg).
Another major focus of our research is neuronal perception of mechanical stimuli. It has been shown that adhesion G-Protein coupled receptors (aGPCR) play a central role in sensing mechanical stimuli by specialised neurons. In recent years, we increased the resolution of the electrophysiological method, which is routinely used to analyse the function of the aGPCR Latrophilin in chordotonal organs of Drosophila larvae. The improved resolution allows us to analyse the function of Latrophilin isoforms, which was not feasible before (cooperation with the Scholz lab, RSI Biochemistry, Leipzig).
Most discoveries in neurosciences stem from studying humans and bilaterally symmetric animals like Drosophila, mice, C. elegans and Aplysia. Bilaterians appeared 540 million years ago, nervous systems, however, already existed in evolutionary older animals, e.g. in Hydra. This group of radially symmetric animals is a member of the Cnidaria phylum. They have an anatomically simple nerve net and show a robust set of behaviours. Interestingly, Hydra regenerates all of its cells within days. The animal shows no senescence and is therefore thought to be potentially immortal. Additionally, Hydra shows remarkable regeneration capabilities. The animal can be enzymatically dissolved into single cells and re-aggregate into a functioning animal. The function of Hydra’s nervous system as for all animals outside the bilateria group is mostly enigmatic. We aim to shed light on the function of the evolutionary ancient nervous system of this animal by developing electrophysiological readouts to investigate synaptic function of Hydra.

 

Team

  • Marie Gläser (MD candidate)
  • Helene Jöchel (MD candidate)
  • Katharina Götze (MD candidate, jointly with Langenhan lab and Abou Jamra lab)
  • Franz Müller (MD candidate, jointly with Langenhan lab and Abou Jamra lab)

Alumni:

  • Joris Lehmann (MSc student, jointly with Scholz lab)
  • Marek Körner (MSc Student 2020, jointly with Scholz lab)

 

Funding

  • Synaptische Langzeitplastizität an einer neuromuskulären Synapse (funded by the Medical Faculty, Leipzig University, ended 06/2019)

  

Publications

  • Ljaschenko, D., Ehmann, N., and Kittel, R.J. (2013) Hebbian plasticity guides maturation of glutamate receptor fields in vivo. Cell Reports.

  • Stock, P.*, Ljaschenko, D.*, Heckmann, M., Dudel J. (2014) Agonists binding nicotinic receptors elicit specific channel opening patterns at αγ or αδ sites. Journal of Physiology.

  • Ehmann N., van de Linde S., Alon A., Ljaschenko D., Keung XZ., Holm T., Rings A., DiAntonio A., Hallermann S., Ashery U., Heckmann M., Sauer M., Kittel RJ. (2014) Quantitative super-resolution imaging of Bruchpilot distinguishes active zone states. Nature Communications.

  • Dawydow A. *, Gueta R. *, Ljaschenko D., Ullrich S., Hermann M., Ehmann N., Gao S., Fiala A., Langenhan T., Nagel G., Kittel RJ. (2014) Channelrhodopsin-2-XXL, a powerful optogenetic tool for low-light applications. PNAS.

  • Scholz N. *, Gehring J. *, Guan C. *, Ljaschenko D., Fischer R., Lakshmanan V., Kittel RJ., Langenhan T. (2014) The adhesion GPCR latrophilin/CIRL shapes mechanosensation. Cell Reports.

  • Beck K., Ehmann N., Andlauer TF., Ljaschenko D., Strecker K., Fischer M., Kittel RJ., Raabe T. (2015) Loss of the Coffin-Lowry syndrome-associated gene RSK2 alters ERK activity, synaptic function and axonal transport in Drosophila motoneurons. Disease models and mechanisms.