TY  - JOUR
A1  - Kollert, Sina
A1  - Dombert, Benjamin
A1  - Döring, Frank
A1  - Wischmeyer, Erhard
T1  - Activation of TRESK channels by the inflammatory mediator lysophosphatidic acid balances nociceptive signalling
JF  - Scientific Reports
N2  - In dorsal root ganglia (DRG) neurons TRESK channels constitute a major current component of the standing outward current IK\(_{SO}\). A prominent physiological role of TRESK has been attributed to pain sensation. During inflammation mediators of pain e.g. lysophosphatidic acid (LPA) are released and modulate nociception. We demonstrate co-expression of TRESK and LPA receptors in DRG neurons. Heterologous expression of TRESK and LPA receptors in Xenopus oocytes revealed augmentation of basal K\(^{+}\) currents upon LPA application. In DRG neurons nociception can result from TRPV\(_{1}\) activation by capsaicin or LPA. Upon co-expression in Xenopus oocytes LPA simultaneously increased both depolarising TRPV\(_{1}\) and hyperpolarising TRESK currents. Patch-clamp recordings in cultured DRG neurons from TRESK[wt] mice displayed increased IK\(_{SO}\) after application of LPA whereas under these conditions IK\(_{SO}\) in neurons from TRESK[ko] mice remained unaltered. Under current-clamp conditions LPA application differentially modulated excitability in these genotypes upon depolarising pulses. Spike frequency was attenuated in TRESK[wt] neurons and, in contrast, augmented in TRESK[ko] neurons. Accordingly, excitation of nociceptive neurons by LPA is balanced by co-activation of TRESK channels. Hence excitation of sensory neurons is strongly controlled by the activity of TRESK channels, which therefore are good candidates for the treatment of pain disorders.
KW  - protein coupled receptors
KW  - molecular mechanisms
KW  - neuropathic pain
KW  - migraine
KW  - initiation
KW  - modulation
KW  - cells
KW  - sensory neurons
KW  - domain K\(^{+}\) channels
KW  - 2-pore potassium channel
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-148312
VL  - 5
IS  - 12548
ER  - 
TY  - JOUR
A1  - Atak, Sinem
A1  - Langlhofer, Georg
A1  - Schaefer, Natascha
A1  - Kessler, Denise
A1  - Meiselbach, Heike
A1  - Delto, Carolyn
A1  - Schindelin, Hermann
A1  - Villmann, Carmen
T1  - Disturbances of ligand potency and enhanced degradation of the human glycine receptor at affected positions G160 and T162 originally identified in patients suffering from hyperekplexia
JF  - Frontiers in Molecular Neuroscience
N2  - Ligand-binding of Cys-loop receptors is determined by N-terminal extracellular loop structures from the plus as well as from the minus side of two adjacent subunits in the pentameric receptor complex. An aromatic residue in loop B of the glycine receptor (GIyR) undergoes direct interaction with the incoming ligand via a cation-π interaction. Recently, we showed that mutated residues in loop B identified from human patients suffering from hyperekplexia disturb ligand-binding. Here, we exchanged the affected human residues by amino acids found in related members of the Cys-loop receptor family to determine the effects of side chain volume for ion channel properties. GIyR variants were characterized in vitro following transfection into cell lines in order to analyze protein expression, trafficking, degradation and ion channel function. GIyR α1 G160 mutations significantly decrease glycine potency arguing for a positional effect on neighboring aromatic residues and consequently glycine-binding within the ligand-binding pocket. Disturbed glycinergic inhibition due to T162 α1 mutations is an additive effect of affected biogenesis and structural changes within the ligand-binding site. Protein trafficking from the ER toward the ER-Golgi intermediate compartment, the secretory Golgi pathways and finally the cell surface is largely diminished, but still sufficient to deliver ion channels that are functional at least at high glycine concentrations. The majority of T162 mutant protein accumulates in the ER and is delivered to ER-associated proteasomal degradation. Hence, G160 is an important determinant during glycine binding. In contrast, 1162 affects primarily receptor biogenesis whereas exchanges in functionality are secondary effects thereof.
KW  - mutations
KW  - trafficking
KW  - domain
KW  - hyperekplexia
KW  - loop B
KW  - side chain properties
KW  - ligand potencies
KW  - Cys-loop receptor
KW  - glycine receptor
KW  - site
KW  - activation
KW  - binding
KW  - channel
KW  - mechanisms
KW  - dominant
KW  - startle
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-144818
VL  - 8
IS  - 79
ER  - 
TY  - JOUR
A1  - Briese, Michael
A1  - Saal, Lena
A1  - Appenzeller, Silke
A1  - Moradi, Mehri
A1  - Baluapuri, Apoorva
A1  - Sendtner, Michael
T1  - Whole transcriptome profiling reveals the RNA content of motor axons
JF  - Nucleic Acids Research
N2  - Most RNAs within polarized cells such as neurons are sorted subcellularly in a coordinated manner. Despite advances in the development of methods for profiling polyadenylated RNAs from small amounts of input RNA, techniques for profiling coding and non-coding RNAs simultaneously are not well established. Here, we optimized a transcriptome profiling method based on double-random priming and applied it to serially diluted total RNA down to 10 pg. Read counts of expressed genes were robustly correlated between replicates, indicating that the method is both reproducible and scalable. Our transcriptome profiling method detected both coding and long non-coding RNAs sized >300 bases. Compared to total RNAseq using a conventional approach our protocol detected 70% more genes due to reduced capture of ribosomal RNAs. We used our method to analyze the RNA composition of compartmentalized motoneurons. The somatodendritic compartment was enriched for transcripts with post-synaptic functions as well as for certain nuclear non-coding RNAs such as 7SK. In axons, transcripts related to translation were enriched including the cytoplasmic non-coding RNA 7SL. Our profiling method can be applied to a wide range of investigations including perturbations of subcellular transcriptomes in neurodegenerative diseases and investigations of microdissected tissue samples such as anatomically defined fiber tracts.
KW  - RNA
KW  - motor axons
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-126800
ER  -