@article{ShemerMekiesBenJehudaetal.2021, author = {Shemer, Yuval and Mekies, Lucy N. and Ben Jehuda, Ronen and Baskin, Polina and Shulman, Rita and Eisen, Binyamin and Regev, Danielle and Arbustini, Eloisa and Gerull, Brenda and Gherghiceanu, Mihaela and Gottlieb, Eyal and Arad, Michael and Binah, Ofer}, title = {Investigating LMNA-related dilated cardiomyopathy using human induced Pluripotent Stem Cell-derived cardiomyocytes}, series = {International Journal of Molecular Sciences}, volume = {22}, journal = {International Journal of Molecular Sciences}, number = {15}, issn = {1422-0067}, doi = {10.3390/ijms22157874}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-285673}, year = {2021}, abstract = {LMNA-related dilated cardiomyopathy is an inherited heart disease caused by mutations in the LMNA gene encoding for lamin A/C. The disease is characterized by left ventricular enlargement and impaired systolic function associated with conduction defects and ventricular arrhythmias. We hypothesized that LMNA-mutated patients' induced Pluripotent Stem Cell-derived cardiomyocytes (iPSC-CMs) display electrophysiological abnormalities, thus constituting a suitable tool for deciphering the arrhythmogenic mechanisms of the disease, and possibly for developing novel therapeutic modalities. iPSC-CMs were generated from two related patients (father and son) carrying the same E342K mutation in the LMNA gene. Compared to control iPSC-CMs, LMNA-mutated iPSC-CMs exhibited the following electrophysiological abnormalities: (1) decreased spontaneous action potential beat rate and decreased pacemaker current (I\(_f\)) density; (2) prolonged action potential duration and increased L-type Ca\(^{2+}\) current (I\(_{Ca,L}\)) density; (3) delayed afterdepolarizations (DADs), arrhythmias and increased beat rate variability; (4) DADs, arrhythmias and cessation of spontaneous firing in response to β-adrenergic stimulation and rapid pacing. Additionally, compared to healthy control, LMNA-mutated iPSC-CMs displayed nuclear morphological irregularities and gene expression alterations. Notably, KB-R7943, a selective inhibitor of the reverse-mode of the Na\(^+\)/Ca\(^{2+}\) exchanger, blocked the DADs in LMNA-mutated iPSC-CMs. Our findings demonstrate cellular electrophysiological mechanisms underlying the arrhythmias in LMNA-related dilated cardiomyopathy.}, language = {en} } @article{KrajkaNaujockPaulyetal.2021, author = {Krajka, Victor and Naujock, Maximilian and Pauly, Martje G. and Stengel, Felix and Meier, Britta and Stanslowsky, Nancy and Klein, Christine and Seibler, Philip and Wegner, Florian and Capetian, Philipp}, title = {Ventral Telencephalic Patterning Protocols for Induced Pluripotent Stem Cells}, series = {Frontiers in Cell and Developmental Biology}, volume = {9}, journal = {Frontiers in Cell and Developmental Biology}, issn = {2296-634X}, doi = {10.3389/fcell.2021.716249}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-244607}, year = {2021}, abstract = {The differentiation of human induced pluripotent stem cells (hiPSCs) into specific cell types for disease modeling and restorative therapies is a key research agenda and offers the possibility to obtain patient-specific cells of interest for a wide range of diseases. Basal forebrain cholinergic neurons (BFCNs) play a particular role in the pathophysiology of Alzheimer's dementia and isolated dystonias. In this work, various directed differentiation protocols based on monolayer neural induction were tested for their effectiveness in promoting a ventral telencephalic phenotype and generating BFCN. Ventralizing factors [i.e., purmorphamine and Sonic hedgehog (SHH)] were applied at different time points, time intervals, and concentrations. In addition, caudal identity was prevented by the use of a small molecule XAV-939 that inhibits the Wnt-pathway. After patterning, gene expression profiles were analyzed by quantitative PCR (qPCR). Rostro-ventral patterning is most effective when initiated simultaneously with neural induction. The most promising combination of patterning factors was 0.5 μM of purmorphamine and 1 μM of XAV-939, which induces the highest expression of transcription factors specific for the medial ganglionic eminence, the source of GABAergic inter- and cholinergic neurons in the telencephalon. Upon maturation of cells, the immune phenotype, as well as electrophysiological properties were investigated showing the presence of marker proteins specific for BFCN (choline acetyltransferase, ISL1, p75, and NKX2.1) and GABAergic neurons. Moreover, a considerable fraction of measured cells displayed mature electrophysiological properties. Synaptic boutons containing the vesicular acetylcholine transporter (VACHT) could be observed in the vicinity of the cells. This work will help to generate basal forebrain interneurons from hiPSCs, providing a promising platform for modeling neurological diseases, such as Alzheimer's disease or Dystonia.}, language = {en} } @article{KarleSchueleKlebeetal.2013, author = {Karle, Kathrin N. and Sch{\"u}le, Rebecca and Klebe, Stephan and Otto, Susanne and Frischholz, Christian and Liepelt-Scarfone, Inga and Sch{\"o}ls, Ludger}, title = {Electrophysiological characterisation of motor and sensory tracts in patients with hereditary spastic paraplegia (HSP)}, series = {Orphanet Journal of Rare Diseases}, volume = {8}, journal = {Orphanet Journal of Rare Diseases}, number = {158}, issn = {1750-1172}, doi = {10.1186/1750-1172-8-158}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-124763}, year = {2013}, abstract = {Background: Hereditary spastic paraplegias (HSPs) are characterised by lower limb spasticity due to degeneration of the corticospinal tract. We set out for an electrophysiological characterisation of motor and sensory tracts in patients with HSP. Methods: We clinically and electrophysiologically examined a cohort of 128 patients with genetically confirmed or clinically probable HSP. Motor evoked potentials (MEPs) to arms and legs, somato-sensory evoked potentials of median and tibial nerves, and nerve conduction studies of tibial, ulnar, sural, and radial nerves were assessed. Results: Whereas all patients showed clinical signs of spastic paraparesis, MEPs were normal in 27\% of patients and revealed a broad spectrum with axonal or demyelinating features in the others. This heterogeneity can at least in part be explained by different underlying genotypes, hinting for distinct pathomechanisms in HSP subtypes. In the largest subgroup, SPG4, an axonal type of damage was evident. Comprehensive electrophysiological testing disclosed a more widespread affection of long fibre tracts involving peripheral nerves and the sensory system in 40\%, respectively. Electrophysiological abnormalities correlated with the severity of clinical symptoms. Conclusions: Whereas HSP is primarily considered as an upper motoneuron disorder, our data suggest a more widespread affection of motor and sensory tracts in the central and peripheral nervous system as a common finding in HSP. The distribution patterns of electrophysiological abnormalities were associated with distinct HSP genotypes and could reflect different underlying pathomechanisms. Electrophysiological measures are independent of symptomatic treatment and may therefore serve as a reliable biomarker in upcoming HSP trials.}, language = {en} }