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@PHDTHESIS{Epple:282311,
author = {Epple, Robert},
title = {{T}he {S}ynaptic {RNA}ome - identification, interactions
and intercellular transfer},
school = {Georg-August-Universität Göttingen},
type = {Dissertation},
reportid = {DZNE-2025-01281},
pages = {122 p.},
year = {2021},
note = {Dissertation, Georg-August-Universität Göttingen, 2021},
abstract = {Synaptic plasticity is how neurons adapt to new stimuli and
necessitates changes in synaptic weight. For these changes
to be durable, local translation in neurites, and at pre-
and post-synapses is required. Current methods do not
capture the pool of local RNAs in its entirety and focus
mainly on mRNAs. Here, I focused on wide-scale interactions
between non-coding RNAs and mRNAs at hippocampal synapses;
data were collected from synaptosomes and an advanced
microfluidic culture system. This new method, SNIDER
(SyNapse Isolation DevicE by Refined Cutting), was developed
to obtain pure neuronal, neurite-localized RNAs; it works by
precisely cutting the synaptic compartment of microfluidic
chambers, yielding more mRNAs than synaptosome isolation. I
also used SNIDER to study the effects of KCl stimulation on
the local RNAome. In another experiment, synapses were
locally perfused with an inhibitor of miR-9-5p, an abundant
microRNA in synaptosomes that is linked to neuronal
development as well as dendrite morphology. Surprisingly,
after isolation of inhibited synapses with SNIDER, I found
the local transcriptome to be unchanged - even though
miR-9-5p inhibition produced clear effects in neuronal
somata. Our findings, taken together with existing
literature, suggested a glial origin of synaptic miR-9-5p.
Astrocytes are highly abundant glia cells and their end feet
often engulf the pre- and postsynapse to form the
tri-partite synapse. To study astrocyte to neuron RNA
transfer, I designed a novel method, InSUREns
(Intercellularly Shipped and Uptaken RNAs Ensnared), whereby
astrocytic RNAs were labeled with 4-thiouracil and neuronal
ribosomes were labeled with HA-tags. By applying a double
pull-down strategy, astrocytic RNAs that were transported
into neurons for translation can then be identified.
Astrocyte-derived extracellular vesicles (ADEV) were
investigated as the means of RNA transportation. Indeed,
ADEV internalization took place over the whole neuronal cell
body, including neurites. ADEVs furthermore contained many
RNAs that where identified via InSUREns. Additionally, many
lncRNAs were present in ADEVs that are known to interact
with synaptic RNAs. These data suggest an important role of
ADEVs in supplying neuronal and synaptic RNAs. Finally, a
hypothesis is developed, how astrocytic RNAs could form the
synaptic tag in the synaptic tagging and capturing model.},
cin = {AG Fischer},
cid = {I:(DE-2719)1410002},
pnm = {352 - Disease Mechanisms (POF4-352)},
pid = {G:(DE-HGF)POF4-352},
typ = {PUB:(DE-HGF)11},
url = {https://pub.dzne.de/record/282311},
}