@article{SalehiZarePrezzaetal.2023, author = {Salehi, Saeede and Zare, Abdolhossein and Prezza, Gianluca and Bader, Jakob and Schneider, Cornelius and Fischer, Utz and Meissner, Felix and Mann, Matthias and Briese, Michael and Sendtner, Michael}, title = {Cytosolic Ptbp2 modulates axon growth in motoneurons through axonal localization and translation of Hnrnpr}, series = {Nature Communications}, volume = {14}, journal = {Nature Communications}, doi = {10.1038/s41467-023-39787-6}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-357639}, year = {2023}, abstract = {The neuronal RNA-binding protein Ptbp2 regulates neuronal differentiation by modulating alternative splicing programs in the nucleus. Such programs contribute to axonogenesis by adjusting the levels of protein isoforms involved in axon growth and branching. While its functions in alternative splicing have been described in detail, cytosolic roles of Ptbp2 for axon growth have remained elusive. Here, we show that Ptbp2 is located in the cytosol including axons and growth cones of motoneurons, and that depletion of cytosolic Ptbp2 affects axon growth. We identify Ptbp2 as a major interactor of the 3' UTR of Hnrnpr mRNA encoding the RNA-binding protein hnRNP R. Axonal localization of Hnrnpr mRNA and local synthesis of hnRNP R protein are strongly reduced when Ptbp2 is depleted, leading to defective axon growth. Ptbp2 regulates hnRNP R translation by mediating the association of Hnrnpr with ribosomes in a manner dependent on the translation factor eIF5A2. Our data thus suggest a mechanism whereby cytosolic Ptbp2 modulates axon growth by fine-tuning the mRNA transport and local synthesis of an RNA-binding protein.}, language = {en} } @article{MassihVehSchenkeetal.2023, author = {Massih, Bita and Veh, Alexander and Schenke, Maren and Mungwa, Simon and Seeger, Bettina and Selvaraj, Bhuvaneish T. and Chandran, Siddharthan and Reinhardt, Peter and Sterneckert, Jared and Hermann, Andreas and Sendtner, Michael and L{\"u}ningschr{\"o}r, Patrick}, title = {A 3D cell culture system for bioengineering human neuromuscular junctions to model ALS}, series = {Frontiers in Cell and Developmental Biology}, volume = {11}, journal = {Frontiers in Cell and Developmental Biology}, issn = {2296-634X}, doi = {10.3389/fcell.2023.996952}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-304161}, year = {2023}, abstract = {The signals that coordinate and control movement in vertebrates are transmitted from motoneurons (MNs) to their target muscle cells at neuromuscular junctions (NMJs). Human NMJs display unique structural and physiological features, which make them vulnerable to pathological processes. NMJs are an early target in the pathology of motoneuron diseases (MND). Synaptic dysfunction and synapse elimination precede MN loss suggesting that the NMJ is the starting point of the pathophysiological cascade leading to MN death. Therefore, the study of human MNs in health and disease requires cell culture systems that enable the connection to their target muscle cells for NMJ formation. Here, we present a human neuromuscular co-culture system consisting of induced pluripotent stem cell (iPSC)-derived MNs and 3D skeletal muscle tissue derived from myoblasts. We used self-microfabricated silicone dishes combined with Velcro hooks to support the formation of 3D muscle tissue in a defined extracellular matrix, which enhances NMJ function and maturity. Using a combination of immunohistochemistry, calcium imaging, and pharmacological stimulations, we characterized and confirmed the function of the 3D muscle tissue and the 3D neuromuscular co-cultures. Finally, we applied this system as an in vitro model to study the pathophysiology of Amyotrophic Lateral Sclerosis (ALS) and found a decrease in neuromuscular coupling and muscle contraction in co-cultures with MNs harboring ALS-linked SOD1 mutation. In summary, the human 3D neuromuscular cell culture system presented here recapitulates aspects of human physiology in a controlled in vitro setting and is suitable for modeling of MND.}, language = {en} } @article{AndreskaLueningschroerWolfetal.2023, author = {Andreska, Thomas and L{\"u}ningschr{\"o}r, Patrick and Wolf, Daniel and McFleder, Rhonda L. and Ayon-Olivas, Maurilyn and Rattka, Marta and Drechsler, Christine and Perschin, Veronika and Blum, Robert and Aufmkolk, Sarah and Granado, Noelia and Moratalla, Rosario and Sauer, Markus and Monoranu, Camelia and Volkmann, Jens and Ip, Chi Wang and Stigloher, Christian and Sendtner, Michael}, title = {DRD1 signaling modulates TrkB turnover and BDNF sensitivity in direct pathway striatal medium spiny neurons}, series = {Cell Reports}, volume = {42}, journal = {Cell Reports}, number = {6}, doi = {10.1016/j.celrep.2023.112575}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-349932}, year = {2023}, abstract = {Highlights • Dopamine receptor-1 activation induces TrkB cell-surface expression in striatal neurons • Dopaminergic deficits cause TrkB accumulation and clustering in the ER • TrkB clusters colocalize with cargo receptor SORCS-2 in direct pathway striatal neurons • Intracellular TrkB clusters fail to fuse with lysosomes after dopamine depletion Summary Disturbed motor control is a hallmark of Parkinson's disease (PD). Cortico-striatal synapses play a central role in motor learning and adaption, and brain-derived neurotrophic factor (BDNF) from cortico-striatal afferents modulates their plasticity via TrkB in striatal medium spiny projection neurons (SPNs). We studied the role of dopamine in modulating the sensitivity of direct pathway SPNs (dSPNs) to BDNF in cultures of fluorescence-activated cell sorting (FACS)-enriched D1-expressing SPNs and 6-hydroxydopamine (6-OHDA)-treated rats. DRD1 activation causes enhanced TrkB translocation to the cell surface and increased sensitivity for BDNF. In contrast, dopamine depletion in cultured dSPN neurons, 6-OHDA-treated rats, and postmortem brain of patients with PD reduces BDNF responsiveness and causes formation of intracellular TrkB clusters. These clusters associate with sortilin related VPS10 domain containing receptor 2 (SORCS-2) in multivesicular-like structures, which apparently protects them from lysosomal degradation. Thus, impaired TrkB processing might contribute to disturbed motor function in PD.}, language = {en} }