TY - THES A1 - Clausen, Jan-Dierk T1 - Der Einfluss des Kalziumkanalagonisten R-Roscovitine auf die Entwicklung und Differenzierung kultivierter primärer Motoneurone eines murinen Modellorganismus für spinale Muskelatrophie Typ I T1 - The influence of the calcium channel agonist R-Roscovitine on the maturation and growth behaviour of isolated primary motoneurons from a spinal muscular atrophy type I mouse model N2 - Die spinale Muskelatrophie ist nach der zystischen Fibrose die zweithäufigste Erkrankung mit autosomal-rezessivem Erbgang und Todesfolge bei Kindern. Der Mangel an intaktem SMN-Protein führt zu einer retrograden Degeneration der Motoneurone. Je nach prozentualem Mangel des SMN-Proteins ergeben sich unterschiedliche Verlaufsformen. Im Falle der schwersten Form liegt die Lebenserwartung unter zwei Jahren für Neugeborene. Die genaue Ursache der spinalen Muskelatrophie ist nicht abschließend geklärt. Klar ist jedoch, dass eine Differenzierungsdefekt an der muskulären Endplatte der Motoneurone vorliegt. In Zusammenschau der hier generierten Ergebnisse und zahlreicher Vorarbeiten zeigt sich, dass eine gestörte Kalziumhomöostase mitverantwortlich für diese Differenzierungsstörung ist. Dies ist am ehesten durch gestörte lokale Kalziumtransienten und eine veränderte Mikrostruktur der Endplatte, im Sinne des Fehlens der für die Differenzierung essentiellen Kalziumkanal-Cluster, zu erklären. Auch wenn die Wiederherstellung der Kalziumhomöostase keinen Einfluss auf die Menge an vorhandenem SMN-Protein hat, zeigt der Einsatz des Kalziumkanalagonisten R-Roscovitine eine restitutio des Phänotyps kultivierter Motoneurone in vitro, sowie auch eine signifikante Lebensverlängerung von murinen Tieren mit einer der SMA I äquivalenten Verlaufsform in vivo. Auch wenn es sich im Falle des Einsatzes von Kalziumkanalagonisten nicht um eine kausale Therapie, wie zum Beispiel im Falle gentechnologischer Ansätze, handelt, stellen sie trotzdem eine vielversprechende Ergänzung des Portfolios an therapeutischen Optionen dar. Die Stärke liegt hierbei in dem sofortigen Wirkeintritt nach Applikation mit antizipiert rascher Symptomverbesserung. N2 - Spinal muscular atrophy is with an incidence around 1:3000 the second most common autosomal recessive disease with possible fatal outcome in children. The lack of intact Smn protein causes retrograde degeneration of motoneurons in the anterior horn of the spinal cord. Depending of the relative deficit in the total amount of intact Smn protein different clinical phenotypes are described. In case of the severest form SMA type I the expected life span is below 24 months. The specific underlying pathophysiological mechanism which cause SMA are so far not fully understood, but there is a consensus that the tremendous lack of Smn protein causes a defect in the differentiation of the neuromuscular junction. Combining the results of my work with the existing literature we suggest that an altered calcium homeostasis at the neuromuscular junction contributes to the retrograde degeneration of the motoneurons. Previous work showed an altered calcium channel clustering at the neuromuscular junction with consecutive lower spontaneous calcium currents. We therefore tested the effect of the calcium channel agonist R-Roscovitine on the maturation and growth behavior of isolated primary motoneurons from an SMA type I mouse model. Despite the fact that the R-Roscovitine treatment has no effect on the amount of intact Smn protein we could show that the treatment lead to a tremendous improvement of the SMA phenotype in vitro. The axonal growth defect as well as the microstructure and size of the growth cones were nearly fully restored by the R-Roscovitine treatment. Further in vivo investigations are needed to prove these results. KW - Spinale Muskelatrophie KW - Motoneuronenerkrankungen KW - Kalziumkanalagonisten KW - neurodegenerative disorder Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-216990 ER - TY - JOUR A1 - Carroll, Patrick A1 - Sendtner, Michael A1 - Meyer, Michael A1 - Thoenen, Hans T1 - Rat ciliary neurothrophic factor (CNTF): gene structure and regulation of mRNA levels in glial cell cultures. N2 - The structure of the rat ciliary neurotrophic factor (CNTF) gene and the regulation ofCNTF mRNA levels in cultured glial cells were investigated. The rat mRNA is encoded by a simple two-exon transcription unit. Sequence analysis of the region upstream of the transcription start-site did not reveal a typical TATA-box consensus sequence. Low levels of CNTF mRNA were detected in cultured Schwann cells, and CNTF mRNA was not increased by a variety of treatments. Three-week-old astrocyteenriched cell cultures from new-born rat brain contained easily detectable CNTF mRNA. In astrocyte-enriched cultures, upregulation of CNTF mRNA levels was observed after treatment with IFN-gamma. CNTF mRNA levels were down-regulated in these cells by treatments that elevate intracellular cyclic AMP and by members of the fibroblast growth factor (FGF) family. The implications of these results for potential in vivo functions of CNTF are discussed. KW - Astrocytes ; Schwann cells ; Interferon-gamma ; Fibroblast growth factor ; Cyclic AMP Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-31763 ER - TY - JOUR A1 - Buchner, Erich A1 - Blanco Redondo, Beatriz A1 - Bunz, Melanie A1 - Halder, Partho A1 - Sadanandappa, Madhumala K. A1 - Mühlbauer, Barbara A1 - Erwin, Felix A1 - Hofbauer, Alois A1 - Rodrigues, Veronica A1 - VijayRaghavan, K. A1 - Ramaswami, Mani A1 - Rieger, Dirk A1 - Wegener, Christian A1 - Förster, Charlotte T1 - Identification and Structural Characterization of Interneurons of the Drosophila Brain by Monoclonal Antibodies of the Würzburg Hybridoma Library JF - PLoS ONE N2 - Several novel synaptic proteins have been identified by monoclonal antibodies (mAbs) of the Würzburg hybridoma library generated against homogenized Drosophila brains, e.g. cysteine string protein, synapse-associated protein of 47 kDa, and Bruchpilot. However, at present no routine technique exists to identify the antigens of mAbs of our library that label only a small number of cells in the brain. Yet these antibodies can be used to reproducibly label and thereby identify these cells by immunohistochemical staining. Here we describe the staining patterns in the Drosophila brain for ten mAbs of the Würzburg hybridoma library. Besides revealing the neuroanatomical structure and distribution of ten different sets of cells we compare the staining patterns with those of antibodies against known antigens and GFP expression patterns driven by selected Gal4 lines employing regulatory sequences of neuronal genes. We present examples where our antibodies apparently stain the same cells in different Gal4 lines suggesting that the corresponding regulatory sequences can be exploited by the split-Gal4 technique for transgene expression exclusively in these cells. The detection of Gal4 expression in cells labeled by mAbs may also help in the identification of the antigens recognized by the antibodies which then in addition to their value for neuroanatomy will represent important tools for the characterization of the antigens. Implications and future strategies for the identification of the antigens are discussed. KW - cell staining KW - drosophila melanogaster KW - gene expression KW - hybridomas KW - immune serum KW - library screening KW - monoclonal antibodies KW - neurons Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-97109 ER - TY - JOUR A1 - Briese, Michael A1 - Sendtner, Michael T1 - Keeping the balance: the noncoding RNA 7SK as a master regulator for neuron development and function JF - BioEssays N2 - The noncoding RNA 7SK is a critical regulator of transcription by adjusting the activity of the kinase complex P-TEFb. Release of P-TEFb from 7SK stimulates transcription at many genes by promoting productive elongation. Conversely, P-TEFb sequestration by 7SK inhibits transcription. Recent studies have shown that 7SK functions are particularly important for neuron development and maintenance and it can thus be hypothesized that 7SK is at the center of many signaling pathways contributing to neuron function. 7SK activates neuronal gene expression programs that are key for terminal differentiation of neurons. Proteomics studies revealed a complex protein interactome of 7SK that includes several RNA-binding proteins. Some of these novel 7SK subcomplexes exert non-canonical cytosolic functions in neurons by regulating axonal mRNA transport and fine-tuning spliceosome production in response to transcription alterations. Thus, a picture emerges according to which 7SK acts as a multi-functional RNA scaffold that is integral for neuron homeostasis. KW - medicine Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-256613 VL - 43 IS - 8 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 - TY - INPR A1 - Brenner, Marian A1 - Zink, Christoph A1 - Witzinger, Linda A1 - Keller, Angelika A1 - Hadamek, Kerstin A1 - Bothe, Sebastian A1 - Neuenschwander, Martin A1 - Villmann, Carmen A1 - von Kries, Jens Peter A1 - Schindelin, Hermann A1 - Jeanclos, Elisabeth A1 - Gohla, Antje T1 - 7,8-Dihydroxyflavone is a direct inhibitor of pyridoxal phosphatase T2 - eLife N2 - Vitamin B6 deficiency has been linked to cognitive impairment in human brain disorders for decades. Still, the molecular mechanisms linking vitamin B6 to these pathologies remain poorly understood, and whether vitamin B6 supplementation improves cognition is unclear as well. Pyridoxal phosphatase (PDXP), an enzyme that controls levels of pyridoxal 5’-phosphate (PLP), the co-enzymatically active form of vitamin B6, may represent an alternative therapeutic entry point into vitamin B6-associated pathologies. However, pharmacological PDXP inhibitors to test this concept are lacking. We now identify a PDXP and age-dependent decline of PLP levels in the murine hippocampus that provides a rationale for the development of PDXP inhibitors. Using a combination of small molecule screening, protein crystallography and biolayer interferometry, we discover and analyze 7,8-dihydroxyflavone (7,8-DHF) as a direct and potent PDXP inhibitor. 7,8-DHF binds and reversibly inhibits PDXP with low micromolar affinity and sub-micromolar potency. In mouse hippocampal neurons, 7,8-DHF increases PLP in a PDXP-dependent manner. These findings validate PDXP as a druggable target. Of note, 7,8-DHF is a well-studied molecule in brain disorder models, although its mechanism of action is actively debated. Our discovery of 7,8-DHF as a PDXP inhibitor offers novel mechanistic insights into the controversy surrounding 7,8-DHF-mediated effects in the brain. KW - 7,8-dihydroxyflavone (7,8-DHF) KW - pyridoxal phosphatase (PDXP) KW - vitamin B6 KW - PDXP inhibitors Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-350446 ER - TY - JOUR A1 - Breitinger, Ulrike A1 - Bahnassawy, Lamiaa M. A1 - Janzen, Dieter A1 - Römer, Vera A1 - Becker, Cord-Michael A1 - Villmann, Carmen A1 - Breitinger, Hans-Georg T1 - PKA and PKC modulators affect ion channel function and internalization of recombinant alpha1 and alpha1-beta glycine receptors JF - Frontiers in Molecular Neurosience N2 - Glycine receptors (GlyRs) are important mediators of fast inhibitory neurotransmission in the mammalian central nervous system. Their function is controlled by multiple cellular mechanisms, including intracellular regulatory processes. Modulation of GlyR function by protein kinases has been reported for many cell types, involving different techniques, and often yielding contradictory results. Here, we studied the effects of protein kinase C (PKC) and cAMP-dependent protein kinase A (PKA) on glycine induced currents in HEK293 cells expressing human homomeric \(\alpha\)1 and heteromeric \(\alpha\)1-\(\beta\) GlyRs using whole-cell patch clamp techniques as well as internalization assays. In whole-cell patch-clamp measurements, modulators were applied in the intracellular buffer at concentrations between 0.1 \(\mu\)M and 0.5 \(\mu\)M. EC50 of glycine increased upon application of the protein kinase activators Forskolin and phorbol-12-myristate-13-acetate (PMA) but decreased in the presence of the PKC inhibitor Staurosporine aglycon and the PKA inhibitor H-89. Desensitization of recombinant \(\alpha\)1 receptors was significantly increased in the presence of Forskolin. Staurosporine aglycon, on the other hand decreased desensitization of heteromeric \(\alpha\)1-\(\beta\) GlyRs. The time course of receptor activation was determined for homomeric \(\alpha\)1 receptors and revealed two simultaneous effects: cells showed a decrease of EC50 after 3-6 min of establishing whole-cell configuration. This effect was independent of protein kinase modulators. All modulators of PKA and PKC, however, produced an additional shift of EC50, which overlay and eventually exceeded the cells intrinsic variation of EC50. The effect of kinase activators was abolished if the corresponding inhibitors were co-applied, consistent with PKA and PKC directly mediating the modulation of GlyR function. Direct effects of PKA-and PKC-modulators on receptor expression on transfected HEK cells were monitored within 15 min of drug application, showing a significant increase of receptor internalization with PKA and PKC activators, while the corresponding inhibitors had no significant effect on receptor surface expression or internalization. Our results confirm the observation that phosphorylation via PKA and PKC has a direct effect on the GlyR ion channel complex and plays an important role in the fine-tuning of glycinergic signaling. KW - glycine receptor KW - PKA KW - PKC KW - activators/inhibitors of phosphorylation KW - whole-cell currents KW - modulation kinetics KW - receptor internalization Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-220401 VL - 11 ER - TY - JOUR A1 - Borasio, Gian Domenico A1 - John, Jacob A1 - Wittinghofer, Alfred A1 - Barde, Yves-Alain A1 - Sendtner, Michael A1 - Heumann, Rolf T1 - ras p21 protein promotes survival and fiber outgrowth of cultured embryonic neurons N2 - Although evidence obtained with the PC12 cell line has suggested a role for the ras oncogene proteins in the signal transduction of nerve growth factor-mediated fiber outgrowth, little is known about the signal transduction mechanisms involved in the neuronal response to neurotrophic factors in nontransformed cells. We report here that the oncogene protein T24-ras, when introduced into the cytoplasm of freshly dissociated chick embryonic neurons, promotes the in vitro survival and neurite outgrowth of nerve growth factor-responsive dorsal rootganglion neurons, brain-derived neurotrophic factor-responsive nodose ganglion neurons, and ciliary neuronotrophic factor-responsive ciliary ganglion neurons. The proto-oncogene product c-Ha-ras also promotes neuronal survival, albeit less strongly. No effect could be observed with truncated counterparts of T24-ras and c-Ha-ras lacking the 23 C-terminal amino acids including the membrane-an-choring, palmityl-accepting cysteine. These results sug-gest a generalized involvement of ras or ras-like proteins in the intracellular signal transduction pathway for neurotrophic factors. Y1 - 1989 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-32621 ER - TY - JOUR A1 - Bieniussa, Linda A1 - Kahraman, Baran A1 - Skornicka, Johannes A1 - Schulte, Annemarie A1 - Voelker, Johannes A1 - Jablonka, Sibylle A1 - Hagen, Rudolf A1 - Rak, Kristen T1 - Pegylated insulin-like growth factor 1 attenuates hair cell loss and promotes presynaptic maintenance of medial olivocochlear cholinergic fibers in the cochlea of the progressive motor neuropathy mouse JF - Frontiers in Neurology N2 - The progressive motor neuropathy (PMN) mouse is a model of an inherited motor neuropathy disease with progressive neurodegeneration. Axon degeneration associates with homozygous mutations of the TBCE gene encoding the tubulin chaperone E protein. TBCE is responsible for the correct dimerization of alpha and beta-tubulin. Strikingly, the PMN mouse also develops a progressive hearing loss after normal hearing onset, characterized by degeneration of the auditory nerve and outer hair cell (OHC) loss. However, the development of this neuronal and cochlear pathology is not fully understood yet. Previous studies with pegylated insulin-like growth factor 1 (peg-IGF-1) treatment in this mouse model have been shown to expand lifespan, weight, muscle strength, and motor coordination. Accordingly, peg-IGF-1 was evaluated for an otoprotective effect. We investigated the effect of peg-IGF-1 on the auditory system by treatment starting at postnatal day 15 (p15). Histological analysis revealed positive effects on OHC synapses of medial olivocochlear (MOC) neuronal fibers and a short-term attenuation of OHC loss. Peg-IGF-1 was able to conditionally restore the disorganization of OHC synapses and maintain the provision of cholinergic acetyltransferase in presynapses. To assess auditory function, frequency-specific auditory brainstem responses and distortion product otoacoustic emissions were recorded in animals on p21 and p28. However, despite the positive effect on MOC fibers and OHC, no restoration of hearing could be achieved. The present work demonstrates that the synaptic pathology of efferent MOC fibers in PMN mice represents a particular form of “efferent auditory neuropathy.” Peg-IGF-1 showed an otoprotective effect by preventing the degeneration of OHCs and efferent synapses. However, enhanced efforts are needed to optimize the treatment to obtain detectable improvements in hearing performances. KW - cochlea KW - microtubules KW - MOC fibers KW - hearing loss KW - pegylated insulin-like growth factor 1 KW - outer hair cell (OHC) KW - motor neuropathy Y1 - 2022 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-276669 SN - 1664-2295 VL - 13 ER - TY - THES A1 - Bender, Florian Lothar Paul T1 - Aufklärung des Pathomechanismus bei der pmn-Mausmutante, einem Mausmodell für Motoneuronerkrankungen T1 - Pathomechanisms in pmn-mice, a model for motoneuron diseases. N2 - Die pmn-Maus dient als Modell für degenerative Motoneuronerkrankungen: Während heterozygote Mäuse klinisch unauffällig sind, entwickeln homozygote einige Anzeichen, wie man sie auch bei humanen Motoneuronerkrankungen findet. Ab der 2. postnatalen Woche weisen sie eine progrediente Schwäche der Hinterläufe auf. Innerhalb kurzer Zeit sind auch andere Muskelgruppen betroffen, was zwischen der 4. und 6. postnatalen Woche zum Tod durch Atemversagen führt. Verantwortlich für die Erkrankung der pmn-Mäuse ist eine Punktmutation im Tubulin-spezifischen Chaperon E (tbce) Gen, die zu einem Aminosäureaustausch an einer evolutionär konservierten Aminosäure im TBCE-Protein führt. TBCE wird ubiquitär exprimiert und spielt eine Rolle bei der Assemblierung der Mikrotubuli. Phänotypisch sind von der Mutation spezifisch Motoneurone betroffen. Nach der Herstellung und Charakterisierung eines Antiserums gegen TBCE war es möglich, nach Unterschieden zwischen pmn-mutierten und wildtypischen Motoneuronen hinsichtlich der Stabilität und der subzellulären Lokalisation des TBCE Proteins zu suchen. Western Blot Analysen mit Rückenmarkslysaten von vier Wochen alten pmn-Mäusen zeigen eine deutliche Reduktion der TBCE-Expression. Mittels Immunfluoreszenz waren in isolierten embryonalen Motoneuronen indes keine Unterschiede hinsichtlich der Expressionsstärke und der subzellulären Lokalisation festzustellen. Das TBCE-Protein wird überwiegend im Zellsoma exprimiert und befindet sich dort im Golgi-Apparat und an den Centrosomen, die als Generatoren der axonalen Mikrotubuli angesehen werden. Obwohl mittels Immunfluoreszenz zu diesem Zeitpunkt keine Unterschiede detektierbar sind, weisen die pmn-mutierten Motoneurone nach sieben Tagen in Kultur einige axonale Pathologien auf, wenn sie in Gegenwart des neurotrophen Faktors BDNF kultiviert werden: Das Längenwachstum der Axone ist deutlich reduziert und entlang der Axone finden sich zahlreiche axonale Schwellungen mit Proteinaggregaten. Elektronenmikroskopisch findet sich eine Reduktion der Mikrotubulianzahl im proximalen Axonabschnitt, während die medialen und distalen Teile eine unveränderte Anzahl an Mikrotubuli aufweisen. Parallel findet sich in allen Axonabschnitten der pmn-mutierten Motoneurone eine deutliche Zunahme an Neurofilamenten. Neben den morphologischen Veränderungen weisen die Motoneurone aus pmn-Mäusen zu diesem Zeitpunkt auch eine Störung im axonalen Transport der Mitochondrien auf, die in den Axonen saltatorisch und bidirektional entlang von Mikrotubuli transportiert werden, auf. So ist die Anzahl stationärer Mitochondrien in pmn-mutierten Motoneuronen signifikant erhöht, während die Anzahl an transportierten Mitochondrien und deren maximale Transportgeschwindigkeit reduziert ist. Die morphologischen Veränderungen und die Störungen im axonalen Transport können kompensiert werden, wenn die pmn-mutierten Motoneurone statt mit BDNF mit dem neurotrophen Faktor CNTF kultiviert werden. Die Effekte von CNTF auf das Längenwachstum der Axone ist STAT3 vermittelt, da pmn-mutierte Motoneurone mit einer STAT3-Defizienz keine Reaktion mehr auf die Gabe von CNTF zeigen. Da STAT3 direkt mit Stathmin interagieren kann und dessen destabilisierende Wirkung auf Mikrotubuli dadurch verhindert, wurde angenommen, dass die STAT3 vermittelten CNTF Effekte auf eine lokale Wirkung von STAT3 in Axonen zurückzuführen ist. Diese Hypothese wird dadurch gestützt, dass die Herunterregulation der Stathmin Expression in pmn-mutierten Motoneuronen den gleichen Effekt auf das Längenwachstum zeigt, wie eine CNTF Gabe während der Kultivierung. N2 - Pmn-mice are used as a model for neurodegenerative motoneurondisease: Whereas heterozygous mice are clinically normal, homozygous mutant mice exhibit many features, which are also observed in human motoneuron disease. The pmn-mice develop normally until the second postnatal week. Then they show weakness of the hind limbs, which rapidly progresses. Within a short time, also other muscle groups are involved, ultimately leading to death of the animals in the 4th to 6th week after birth. The underlying gene defect was found as a point mutation in the tubulin-specific chaperon E (TBCE) gene, which leads to a single amino acid exchange at an evolutionary highly conserved amino acid in TBCE protein. TBCE is ubiquitously expressed and plays a role in microtubule assembly. However, motoneurons are specifically affected and seem to be more vulnerable. After generating an antiserum against TBCE, differences between motoneurons from pmn-mutant mice and control animals with regard to stability and subcellular localization of TBCE protein were analysed. Western blot analysis with lysates of spinal cord from 4 week old pmn-mice showed a reduction of TBCE protein expression. There were no differences in TBCE expression observed in immunocytochemistry with isolated embryonic motoneurons of pmn mice compared to wildtype mice: Neither the protein levels nor the subcellular distribution is altered. There is a strong TBCE immunoreactivity in cell soma of motoneurons, where TBCE is located in Golgi apparatus and at the centrosomes, where axonal microtubules are generated. Even there are no differences of TBCE expression at this time point, there are different axonal pathologies detectable: axon length of 7 days cultured motoneurons is significantly reduced and axonal swellings are visible when motoneurons are cultured with the neurotrophic factor BDNF. The number of microtubules is reduced in proximal parts of the axon and in parallel there is an increase of neurofilaments in all axonal parts, which was detectable by electron microscopy. Apart from the morphological changes in pmn-mutant motoneurons there is a disturbance of axonal transport of mitochondria, which are transported in axons in a saltatory and bidirectional manner along microtubules. In motoneurons from pmn-mice the number of stationary mitochondria is significantly increased and in parallel the number of transported mitochondria as well as their maximum velocity is reduced. Both, the morphological changes as well as the disturbance of axonal transport in pmn-mutant motoneurons can be rescued by treatment with the growth factor CNTF. The effects of CNTF on axonal outgrowth is mediated by STAT3, because rescue of CNTF to axon length is absent in pmn-mutant motoneurons lacking STAT3 expression. It is known that STAT3 can directly interact with stathmin, a regulator of microtubule dynamics. This interaction prevents the microtubule destabilizing activity of stahmin. So we assummed, that the STAT3 mediated effects of CNTF treatment are caused by local mechanisms in the axons. In deed, a shRNA downregulation of stathmin in pmn-mutated motoneurons cultured with BDNF has the same effects like treatment with CNTF. KW - Motoneuronerkrankung KW - pmn-Maus KW - TBCE KW - STAT3 KW - Stathmin KW - motoneuron disease KW - pmn KW - TBCE KW - STAT3 KW - stathmin Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-23711 ER -