scholarly journals Induced pluripotent stem cell-derived primary proprioceptive neurons as Friedreich ataxia cell model

2019 ◽  
Author(s):  
Chiara Dionisi ◽  
Myriam Rai ◽  
Marine Chazalon ◽  
Serge N. Schiffmann ◽  
Massimo Pandolfo

AbstractHuman induced pluripotent stem cells (iPSCs) are used to generate models of human diseases that recapitulate the pathogenic process as it occurs in affected cells. Many differentiated cell types can currently be obtained from iPSCs, but no validated protocol is yet available to specifically generate primary proprioceptive neurons. Proprioceptors are affected in a number of genetic and acquired diseases, including Friedreich ataxia (FRDA).FRDA is a recessive neurodegenerative and systemic disease due to epigenetic suppression of frataxin (FXN) expression caused by the presence of expanded GAA repeats at the FXN locus. The most characteristic early neuropathologic finding in FRDA is the loss of large primary proprioceptive neurons in the dorsal root ganglia (DRGs), with associated loss of large myelinated fibers in the dorsal roots and in the posterior columns of the spinal cord. Both a developmental deficit and progressive neurodegeneration are thought to underlie the loss of proprioceptors in FRDA, though the relative contribution of these two components is unclear. The basis of the high specific vulnerability of proprioceptors in FRDA is also unknown. In order to address these open questions about FRDA pathogenesis and at the same time develop a cell model that can be applied to other conditions primarily affecting proprioceptors, we set up a protocol to differentiate iPSCs into primary proprioceptive neurons. We modified the dual-SMAD inhibition/WNT activation protocol, previously used to generate nociceptor-enriched cultures of primary sensory neurons from iPSCs, to favor instead the generation of proprioceptors. We succeeded in substantially enriching iPSC-derived primary sensory neuron cultures in proprioceptors, largely exceeding the proportion normally represented by these cells in dorsal root ganglia. We also showed that almost pure populations of proprioceptors can be purified from these cultures by fluorescence-activated cell sorting. Finally, we demonstrated that iPSCs from a FRDA patient can generate normal appearing proprioceptors but have subtle differentiation deficits and more limited survival.

2017 ◽  
Author(s):  
Amelié Hu ◽  
Myriam Rai ◽  
Simona Donatello ◽  
Massimo Pandolfo

AbstractEpigenetic suppression of frataxin (FXN) expression caused by the presence of expanded GAA repeats at theFXNlocus is the key pathogenic event in Friedreich ataxia (FRDA), a recessive neurodegenerative and systemic disease. FXN is involved in iron-sulfur (Fe-S) cluster biogenesis in mitochondria, its deficiency causes multiple Fe-S protein deficiencies, mitochondrial dysfunction and oxidative stress. Primary sensory neurons (PSNs) in the dorsal root ganglia (DRGs) are the most vulnerable cells in FRDA, whose abnormal development and degeneration leads to the onset and early progression of ataxia. We generated PSNs from induced pluripotent stem cells (iPSCs) from FRDA patients and showed that they recapitulate the key pathogenic events in FRDA, including low FXN levels, loss of Fe-S proteins and impaired antioxidant responses. We also showed that FXN deficiency in these cells may be partially corrected by a pimelic benzamide histone deacetylase inhibitor, a class of potential therapeutics for FRDA. We generated and validated a cellular model of the most vulnerable neurons in FRDA, which can be used for further studies on pathogenesis and treatment approaches.


2021 ◽  
Vol 10 (14) ◽  
pp. 3061
Author(s):  
Robert N. Hawthorne ◽  
Adriana Blazeski ◽  
Justin Lowenthal ◽  
Suraj Kannan ◽  
Roald Teuben ◽  
...  

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a progressive heart condition which causes fibro-fatty myocardial scarring, ventricular arrhythmias, and sudden cardiac death. Most cases of ARVC can be linked to pathogenic mutations in the cardiac desmosome, but the pathophysiology is not well understood, particularly in early phases when arrhythmias can develop prior to structural changes. Here, we created a novel human induced pluripotent stem cell-derived cardiomyocyte (hiPSC-CM) model of ARVC from a patient with a c.2358delA variant in desmoglein-2 (DSG2). These DSG2-mutant (DSG2Mut) hiPSC-CMs were compared against two wildtype hiPSC-CM lines via immunostaining, RT-qPCR, Western blot, RNA-Seq, cytokine expression and optical mapping. Mutant cells expressed reduced DSG2 mRNA and had altered localization of desmoglein-2 protein alongside thinner, more disorganized myofibrils. No major changes in other desmosomal proteins were noted. There was increased pro-inflammatory cytokine expression that may be linked to canonical and non-canonical NFκB signaling. Action potentials in DSG2Mut CMs were shorter with increased upstroke heterogeneity, while time-to-peak calcium and calcium decay rate were reduced. These were accompanied by changes in ion channel and calcium handling gene expression. Lastly, suppressing DSG2 in control lines via siRNA allowed partial recapitulation of electrical anomalies noted in DSG2Mut cells. In conclusion, the aberrant cytoskeletal organization, cytokine expression, and electrophysiology found DSG2Mut hiPSC-CMs could underlie early mechanisms of disease manifestation in ARVC patients.


Author(s):  
Elliot W. Swartz ◽  
Greg Shintani ◽  
Jijun Wan ◽  
Joseph S. Maffei ◽  
Sarah H. Wang ◽  
...  

SummaryThe failure of the neuromuscular junction (NMJ) is a key component of degenerative neuromuscular disease, yet how NMJs degenerate in disease is unclear. Human induced pluripotent stem cells (hiPSCs) offer the ability to model disease via differentiation toward affected cell types, however, the re-creation of an in vitro neuromuscular system has proven challenging. Here we present a scalable, all-hiPSC-derived co-culture system composed of independently derived spinal motor neurons (MNs) and skeletal myotubes (sKM). In a model of C9orf72-associated disease, co-cultures form functional NMJs that can be manipulated through optical stimulation, eliciting muscle contraction and measurable calcium flux in innervated sKM. Furthermore, co-cultures grown on multi-electrode arrays (MEAs) permit the pharmacological interrogation of neuromuscular physiology. Utilization of this co-culture model as a tunable, patient-derived system may offer significant insights into NMJ formation, maturation, repair, or pathogenic mechanisms that underlie NMJ dysfunction in disease.


2021 ◽  
Author(s):  
Zhengyu Ouyang ◽  
Nathanael Bourgeois ◽  
Eugenia Lyashenko ◽  
Paige Cundiff ◽  
Patrick F Cullen ◽  
...  

Induced pluripotent stem cell (iPSC) derived cell types are increasingly employed as in vitro model systems for drug discovery. For these studies to be meaningful, it is important to understand the reproducibility of the iPSC-derived cultures and their similarity to equivalent endogenous cell types. Single-cell and single-nucleus RNA sequencing (RNA-seq) are useful to gain such understanding, but they are expensive and time consuming, while bulk RNA-seq data can be generated quicker and at lower cost. In silico cell type decomposition is an efficient, inexpensive, and convenient alternative that can leverage bulk RNA-seq to derive more fine-grained information about these cultures. We developed CellMap, a computational tool that derives cell type profiles from publicly available single-cell and single-nucleus datasets to infer cell types in bulk RNA-seq data from iPSC-derived cell lines.


Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Albert J Pedroza ◽  
Samantha Churovich ◽  
Nobu Yokoyama ◽  
Ken Nakamura ◽  
Cristiana Iosef Husted ◽  
...  

Introduction: Mutations in TGF-beta (TGF-ß) signaling genes lead to aortic root aneurysm in Loeys Dietz syndrome (LDS). Smooth muscle cells (SMCs) in the proximal aorta develop from two embryologic origins: second heart field (SHF) and neural crest (NC). Induced pluripotent stem cell (iPSC) models simulate these lineages, but direct correlation to clinical disease is lacking. Hypothesis: iPSC-derived SMCs accurately model lineage-specific aortopathy in LDS. Methods: We generated SMC lines from root and ascending aortic surgical tissue and iPSC-derived SMCs through SHF and NC-specific pathways from an LDS patient ( TGFBR1 mutation). Lineage-specific TGF-ß responses were determined by western blot/ELISA. RNA sequencing and RT-PCR identified SMC transcriptomes. Results: Aortic root SMCs showed greater canonical TGF-ß activation (p-SMAD2/3) versus ascending at baseline and with TGF-ß stimulation ( Figure ). Synonymous results were seen in SHF versus NC SMCs from the iPSC pathway. RNAseq identified 1,600 differentially expressed genes between iPSC lineages, including altered TGF-ß receptor and ligand expression profiles. Primary aortic lines validated iPSC data: root SMCs showed enriched TGF-ß receptor 1/2/3 expression (1.7-, 3.9- and 5.9-fold) while ascending SMCs overexpressed TGFB1 and TGFB2 ligands (1.8- and 3.5-fold). Despite discordant TGF-ß activation, SMC contractile gene expression was similar between lineages in aortic and iPSC-SMCs, suggesting alternative downstream effects in LDS aneurysm. Conclusion: iPSC-derived SMCs effectively model lineage-specific aortic root aneurysm pathology, validating this model as a tool for mechanistic testing and therapy discovery.


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