@article{TejeroAlsakkalHennleinetal.2023, author = {Tejero, Rocio and Alsakkal, Mohammad and Hennlein, Luisa and Lopez-Cabello, Ana M. and Jablonka, Sibylle and Tabares, Lucia}, title = {Nifedipine ameliorates cellular differentiation defects of Smn-deficient motor neurons and enhances neuromuscular transmission in SMA mice}, series = {International Journal of Molecular Sciences}, volume = {24}, journal = {International Journal of Molecular Sciences}, number = {8}, issn = {1422-0067}, doi = {10.3390/ijms24087648}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313636}, year = {2023}, abstract = {In spinal muscular atrophy (SMA), mutations in or loss of the Survival Motor Neuron 1 (SMN1) gene reduce full-length SMN protein levels, which leads to the degeneration of a percentage of motor neurons. In mouse models of SMA, the development and maintenance of spinal motor neurons and the neuromuscular junction (NMJ) function are altered. Since nifedipine is known to be neuroprotective and increases neurotransmission in nerve terminals, we investigated its effects on cultured spinal cord motor neurons and motor nerve terminals of control and SMA mice. We found that application of nifedipine increased the frequency of spontaneous Ca\(^{2+}\) transients, growth cone size, cluster-like formations of Cav2.2 channels, and it normalized axon extension in SMA neurons in culture. At the NMJ, nifedipine significantly increased evoked and spontaneous release at low-frequency stimulation in both genotypes. High-strength stimulation revealed that nifedipine increased the size of the readily releasable pool (RRP) of vesicles in control but not SMA mice. These findings provide experimental evidence about the ability of nifedipine to prevent the appearance of developmental defects in SMA embryonic motor neurons in culture and reveal to which extent nifedipine could still increase neurotransmission at the NMJ in SMA mice under different functional demands.}, language = {en} } @article{WohnradeVellingMixetal.2023, author = {Wohnrade, Camilla and Velling, Ann-Kathrin and Mix, Lucas and Wurster, Claudia D. and Cordts, Isabell and Stolte, Benjamin and Zeller, Daniel and Uzelac, Zeljko and Platen, Sophia and Hagenacker, Tim and Deschauer, Marcus and Lingor, Paul and Ludolph, Albert C. and Lul{\´e}, Doroth{\´e}e and Petri, Susanne and Osmanovic, Alma and Schreiber-Katz, Olivia}, title = {Health-related quality of life in spinal muscular atrophy patients and their caregivers — a prospective, cross-sectional, multi-center analysis}, series = {Brain Sciences}, volume = {13}, journal = {Brain Sciences}, number = {1}, issn = {2076-3425}, doi = {10.3390/brainsci13010110}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-305048}, year = {2023}, abstract = {Spinal muscular atrophy (SMA) is a disabling disease that affects not only the patient's health-related quality of life (HRQoL), but also causes a high caregiver burden (CGB). The aim of this study was to evaluate HRQoL, CGB, and their predictors in SMA. In two prospective, cross-sectional, and multi-center studies, SMA patients (n = 39) and SMA patient/caregiver couples (n = 49) filled in the EuroQoL Five Dimension Five Level Scale (EQ-5D-5L) and the Short Form Health Survey 36 (SF-36). Caregivers (CGs) additionally answered the Zarit Burden Interview (ZBI) and the Hospital Anxiety and Depression Scale (HADS). Patients were clustered into two groups with either low or high HRQoL (EQ-5D-5L index value <0.259 or >0.679). The latter group was mostly composed of ambulatory type III patients with higher motor/functional scores. More severely affected patients reported low physical functioning but good mental health and vitality. The CGB (mean ZBI = 22/88) correlated negatively with patients' motor/functional scores and age. Higher CGB was associated with a lower HRQoL, higher depression and anxiety, and more health impairments of the CGs. We conclude that patient and CG well-being levels interact closely, which highlights the need to consider the health of both parties while evaluating novel treatments.}, language = {en} } @article{DengReinhardHennleinetal.2022, author = {Deng, Chunchu and Reinhard, Sebastian and Hennlein, Luisa and Eilts, Janna and Sachs, Stefan and Doose, S{\"o}ren and Jablonka, Sibylle and Sauer, Markus and Moradi, Mehri and Sendtner, Michael}, title = {Impaired dynamic interaction of axonal endoplasmic reticulum and ribosomes contributes to defective stimulus-response in spinal muscular atrophy}, series = {Translational Neurodegeneration}, volume = {11}, journal = {Translational Neurodegeneration}, number = {1}, issn = {2047-9158}, doi = {10.1186/s40035-022-00304-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300649}, year = {2022}, abstract = {Background: Axonal degeneration and defects in neuromuscular neurotransmission represent a pathological hallmark in spinal muscular atrophy (SMA) and other forms of motoneuron disease. These pathological changes do not only base on altered axonal and presynaptic architecture, but also on alterations in dynamic movements of organelles and subcellular structures that are not necessarily reflected by static histopathological changes. The dynamic interplay between the axonal endoplasmic reticulum (ER) and ribosomes is essential for stimulus-induced local translation in motor axons and presynaptic terminals. However, it remains enigmatic whether the ER and ribosome crosstalk is impaired in the presynaptic compartment of motoneurons with Smn (survival of motor neuron) deficiency that could contribute to axonopathy and presynaptic dysfunction in SMA. Methods: Using super-resolution microscopy, proximity ligation assay (PLA) and live imaging of cultured motoneurons from a mouse model of SMA, we investigated the dynamics of the axonal ER and ribosome distribution and activation. Results: We observed that the dynamic remodeling of ER was impaired in axon terminals of Smn-deficient motoneurons. In addition, in axon terminals of Smn-deficient motoneurons, ribosomes failed to respond to the brain-derived neurotrophic factor stimulation, and did not undergo rapid association with the axonal ER in response to extracellular stimuli. Conclusions: These findings implicate impaired dynamic interplay between the ribosomes and ER in axon terminals of motoneurons as a contributor to the pathophysiology of SMA and possibly also other motoneuron diseases.}, language = {en} } @article{FrancoEspinGatiusArmengoletal.2022, author = {Franco-Espin, Julio and Gatius, Ala{\´o} and Armengol, Jos{\´e} {\´A}ngel and Arumugam, Saravanan and Moradi, Mehri and Sendtner, Michael and Calder{\´o}, Jordi and Tabares, Lucia}, title = {SMN is physiologically downregulated at wild-type motor nerve terminals but aggregates together with neurofilaments in SMA mouse models}, series = {Biomolecules}, volume = {12}, journal = {Biomolecules}, number = {10}, issn = {2218-273X}, doi = {10.3390/biom12101524}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-290263}, year = {2022}, abstract = {Survival motor neuron (SMN) is an essential and ubiquitously expressed protein that participates in several aspects of RNA metabolism. SMN deficiency causes a devastating motor neuron disease called spinal muscular atrophy (SMA). SMN forms the core of a protein complex localized at the cytoplasm and nuclear gems and that catalyzes spliceosomal snRNP particle synthesis. In cultured motor neurons, SMN is also present in dendrites and axons, and forms part of the ribonucleoprotein transport granules implicated in mRNA trafficking and local translation. Nevertheless, the distribution, regulation, and role of SMN at the axons and presynaptic motor terminals in vivo are still unclear. By using conventional confocal microscopy and STED super-resolution nanoscopy, we found that SMN appears in the form of granules distributed along motor axons at nerve terminals. Our fluorescence in situ hybridization and electron microscopy studies also confirmed the presence of β-actin mRNA, ribosomes, and polysomes in the presynaptic motor terminal, key elements of the protein synthesis machinery involved in local translation in this compartment. SMN granules co-localize with the microtubule-associated protein 1B (MAP1B) and neurofilaments, suggesting that the cytoskeleton participates in transporting and positioning the granules. We also found that, while SMN granules are physiologically downregulated at the presynaptic element during the period of postnatal maturation in wild-type (non-transgenic) mice, they accumulate in areas of neurofilament aggregation in SMA mice, suggesting that the high expression of SMN at the NMJ, together with the cytoskeletal defects, contribute to impairing the bi-directional traffic of proteins and organelles between the axon and the presynaptic terminal.}, language = {en} } @article{KoenigPechmannThieleetal.2019, author = {K{\"o}nig, Kirsten and Pechmann, Astrid and Thiele, Simone and Walter, Maggie C. and Schorling, David and Tassoni, Adrian and Lochm{\"u}ller, Hanns and M{\"u}ller-Reible, Clemens and Kirschner, Janbernd}, title = {De-duplicating patient records from three independent data sources reveals the incidence of rare neuromuscular disorders in Germany}, series = {Orphanet Journal of Rare Diseases}, volume = {14}, journal = {Orphanet Journal of Rare Diseases}, doi = {10.1186/s13023-019-1125-2}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-222807}, year = {2019}, abstract = {Background Estimation of incidence in rare diseases is often challenging due to unspecific and incomplete coding and recording systems. Patient- and health care provider-driven data collections are held with different organizations behind firewalls to protect the privacy of patients. They tend to be fragmented, incomplete and their aggregation leads to further inaccuracies, as the duplicated records cannot easily be identified. We here report about a novel approach to evaluate the incidences of Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA) in Germany. Methods We performed a retrospective epidemiological study collecting data from patients with dystrophinopathies (DMD and Becker muscular dystrophy) and SMA born between 1995 and 2018. We invited all neuromuscular centers, genetic institutes and the patient registries for DMD and SMA in Germany to participate in the data collection. A novel web-based application for data entry was developed converting patient identifying information into a hash code. Duplicate entries were reliably allocated to the distinct patient. Results We collected 5409 data entries in our web-based database representing 1955 distinct patients with dystrophinopathies and 1287 patients with SMA. 55.0\% of distinct patients were found in one of the 3 data sources only, while 32.0\% were found in 2, and 13.0\% in all 3 data sources. The highest number of SMA patients was reported by genetic testing laboratories, while for DMD the highest number was reported by the clinical specialist centers. After the removal of duplicate records, the highest yearly incidence for DMD was calculated as 2.57:10,000 in 2001 and the highest incidence for SMA as 1.36:10,000 in 2014. Conclusion With our novel approach (compliant with data protection regulations), we were able to identify unique patient records and estimate the incidence of DMD and SMA in Germany combining and de-duplicating data from patient registries, genetic institutes, and clinical care centers. Although we combined three different data sources, an unknown number of patients might not have been reported by any of these sources. Therefore, our results reflect the minimal incidence of these diseases.}, language = {en} } @article{WetzelJablonkaBlum2013, author = {Wetzel, Andrea and Jablonka, Sibylle and Blum, Robert}, title = {Cell-autonomous axon growth of young motoneurons is triggered by a voltage-gated sodium channel}, series = {Channels (Austin)}, volume = {7}, journal = {Channels (Austin)}, number = {1}, doi = {10.4161/chan.23153}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-132586}, pages = {51-56}, year = {2013}, abstract = {Spontaneous electrical activity preceding synapse formation contributes to the precise regulation of neuronal development. Examining the origins of spontaneous activity revealed roles for neurotransmitters that depolarize neurons and activate ion channels. Recently, we identified a new molecular mechanism underlying fluctuations in spontaneous neuronal excitability. We found that embryonic motoneurons with a genetic loss of the low-threshold sodium channel Na\(_V\)1.9 show fewer fluctuations in intracellular calcium in axonal compartments and growth cones than wild-type littermates. As a consequence, axon growth of Na\(_V\)1.9-deficient motoneurons in cell culture is drastically reduced while dendritic growth and cell survival are not affected. Interestingly, Na\(_V\)1.9 function is observed under conditions that would hardly allow a ligand- or neurotransmitter-dependent depolarization. Thus, Na\(_V\)1.9 may serve as a cell-autonomous trigger for neuronal excitation. In this addendum, we discuss a model for the interplay between cell-autonomous local neuronal activity and local cytoskeleton dynamics in growth cone function.}, language = {en} } @article{KaupmannSendtnerStoecklietal.1991, author = {Kaupmann, Klemens and Sendtner, Michael and St{\"o}ckli, Kurt A. and Jockusch, Harald}, title = {The gene of ciliary neurotrophic factor (cntf) maps to murine chromosome 19 and its expression is not affected in the hereditary motoneuron disease 'wobbler' of the mouse}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-42626}, year = {1991}, abstract = {The cDNA for ciliary neurotrophic factor (CNTF), a polypeptide involved in the survival of motoneurons in mammals, has recently been cloned (St{\"o}ckli et al., Nature, 342, 920 - 923, 1989; Lin et al. Science, 246, 1023 - 1025, 1989). We have now localized the corresponding gene Cntf to chromosome 19 in the mouse, using an interspecific cross between Mus spretus and Mus musculus domesticus. The latter was carrying the gene wobbler (wr) for spinal muscular atrophy. DNA was prepared from backcross individuals and typed for the segregation of species-specific Cntf restriction fragments in relation to DNA markers of known chromosomal location. The M.spretus allele of Cntf cosegregated with chromosome 19 markers and mapped closely to Ly-1, to a region of mouse chromosome 19 with conserved synteny to human chromosome 11q. Cntf is not linked to wr, and the expression of CNTF mRNA and protein appears close to normal in facial and sciatic nerves, of affected (wr/wr) mice, suggesting that motoneuron degeneration of wobbler mice has its origin in defects other than reduced CNTF expression.}, language = {en} }