scholarly journals Sodium channel Nav1.2-L1342P variant displaying complex biophysical properties renders hyperexcitability of cortical neurons derived from human iPSCs

2021 ◽  
Author(s):  
Zhefu Que ◽  
Maria I. Olivero-Acosta ◽  
Jingliang Zhang ◽  
Muriel Eaton ◽  
William C. Skarnes ◽  
...  

AbstractWith the wide adoption of whole-exome sequencing in children having seizures, an increasing number of SCN2A variants has been revealed as possible genetic causes of epilepsy. Voltage-gated sodium channel Nav1.2, encoded by gene SCN2A, is strongly expressed in the pyramidal excitatory neurons and supports action potential firing. One recurrent SCN2A variant is L1342P, which was identified in multiple patients with early-onset encephalopathy and intractable seizures. Our biophysical analysis and computational modeling predicted gain-of-function features of this epilepsy-associated Nav1.2 variant. However, the mechanism underlying L1342P mediated seizures and the pharmacogenetics of this variant in human neurons remain unknown. To understand the core phenotypes of the L1342P variant in human neurons, we took advantage of a reference human induced pluripotent stem cell (hiPSC) line, in which L1342P was engineered by CRISPR/Cas9 mediated genome-editing. Using patch-clamping and micro-electrode array (MEA) recording, we found that the cortical neurons derived from hiPSCs carrying heterozygous L1342P variant presented significantly increased intrinsic excitability, higher sodium current density, and enhanced bursting and synchronous network firing, showing clear hyperexcitability phenotypes. Interestingly, the L1342P neuronal culture displayed a degree of resistance to the anti-seizure medication (phenytoin), which likely recapitulated aspects of clinical observation of patients carrying the L1342P variant. In contrast, phrixotoxin-3 (PTx3), a Nav1.2 isoform-specific blocker, was able to potently alleviate spontaneous and chemical-induced hyperexcitability of neurons carrying the L1342P variant. Our results reveal a possible pathogenic underpinning of Nav1.2-L1342P mediated epileptic seizures, and demonstrate the utility of genome-edited hiPSCs as an in vitro platform to advance personalized phenotyping and drug discovery.

2018 ◽  
Vol 115 (37) ◽  
pp. E8775-E8782 ◽  
Author(s):  
Bastian Zimmer ◽  
Osefame Ewaleifoh ◽  
Oliver Harschnitz ◽  
Yoon-Seung Lee ◽  
Camille Peneau ◽  
...  

Herpes simplex virus type 1 (HSV-1) encephalitis (HSE) is the most common sporadic viral encephalitis in Western countries. Some HSE children carry inborn errors of the Toll-like receptor 3 (TLR3)-dependent IFN-α/β– and -λ–inducing pathway. Induced pluripotent stem cell (iPSC)-derived cortical neurons with TLR3 pathway mutations are highly susceptible to HSV-1, due to impairment of cell-intrinsic TLR3-IFN immunity. In contrast, the contribution of cell-intrinsic immunity of human trigeminal ganglion (TG) neurons remains unclear. Here, we describe efficient in vitro derivation and purification of TG neurons from human iPSCs via a cranial placode intermediate. The resulting TG neurons are of sensory identity and exhibit robust responses to heat (capsaicin), cold (icilin), and inflammatory pain (ATP). Unlike control cortical neurons, both control and TLR3-deficient TG neurons were highly susceptible to HSV-1. However, pretreatment of control TG neurons with poly(I:C) induced the cells into an anti–HSV-1 state. Moreover, both control and TLR3-deficient TG neurons developed resistance to HSV-1 following pretreatment with IFN-β but not IFN-λ. These data indicate that TG neurons are vulnerable to HSV-1 because they require preemptive stimulation of the TLR3 or IFN-α/β receptors to induce antiviral immunity, whereas cortical neurons possess a TLR3-dependent constitutive resistance that is sufficient to block incoming HSV-1 in the absence of prior antiviral signals. The lack of constitutive resistance in TG neurons in vitro is consistent with their exploitation as a latent virus reservoir in vivo. Our results incriminate deficiencies in the constitutive TLR3-dependent response of cortical neurons in the pathogenesis of HSE.


2021 ◽  
Vol 22 (3) ◽  
pp. 1203
Author(s):  
Lu Qian ◽  
Julia TCW

A high-throughput drug screen identifies potentially promising therapeutics for clinical trials. However, limitations that persist in current disease modeling with limited physiological relevancy of human patients skew drug responses, hamper translation of clinical efficacy, and contribute to high clinical attritions. The emergence of induced pluripotent stem cell (iPSC) technology revolutionizes the paradigm of drug discovery. In particular, iPSC-based three-dimensional (3D) tissue engineering that appears as a promising vehicle of in vitro disease modeling provides more sophisticated tissue architectures and micro-environmental cues than a traditional two-dimensional (2D) culture. Here we discuss 3D based organoids/spheroids that construct the advanced modeling with evolved structural complexity, which propels drug discovery by exhibiting more human specific and diverse pathologies that are not perceived in 2D or animal models. We will then focus on various central nerve system (CNS) disease modeling using human iPSCs, leading to uncovering disease pathogenesis that guides the development of therapeutic strategies. Finally, we will address new opportunities of iPSC-assisted drug discovery with multi-disciplinary approaches from bioengineering to Omics technology. Despite technological challenges, iPSC-derived cytoarchitectures through interactions of diverse cell types mimic patients’ CNS and serve as a platform for therapeutic development and personalized precision medicine.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Martin Becker ◽  
Francesca Mastropasqua ◽  
Jan Philipp Reising ◽  
Simon Maier ◽  
Mai-Lan Ho ◽  
...  

Abstract CASK-related disorders are genetically defined neurodevelopmental syndromes. There is limited information about the effects of CASK mutations in human neurons. Therefore, we sought to delineate CASK-mutation consequences and neuronal effects using induced pluripotent stem cell-derived neurons from two mutation carriers. One male case with autism spectrum disorder carried a novel splice-site mutation and a female case with intellectual disability carried an intragenic tandem duplication. We show reduction of CASK protein in maturing neurons from the mutation carriers, which leads to significant downregulation of genes involved in presynaptic development and of CASK protein interactors. Furthermore, CASK-deficient neurons showed decreased inhibitory presynapse size as indicated by VGAT staining, which may alter the excitatory–inhibitory (E/I) balance in developing neural circuitries. Using in vivo magnetic resonance spectroscopy quantification of GABA in the male mutation carrier, we further highlight the possibility to validate in vitro cellular data in the brain. Our data show that future pharmacological and clinical studies on targeting presynapses and E/I imbalance could lead to specific treatments for CASK-related disorders.


2015 ◽  
Vol 10s1 ◽  
pp. BMI.S20066 ◽  
Author(s):  
Seok-Man Ho ◽  
Aaron Topol ◽  
Kristen J. Brennand

Aberrant behavior and function of neurons are believed to be the primary causes of most neurological diseases and psychiatric disorders. Human postmortem samples have limited availability and, while they provide clues to the state of the brain after a prolonged illness, they offer limited insight into the factors contributing to disease onset. Conversely, animal models cannot recapitulate the polygenic origins of neuropsychiatric disease. Novel methods, such as somatic cell reprogramming, deliver nearly limitless numbers of pathogenic human neurons for the study of the mechanism of neuropsychiatric disease initiation and progression. First, this article reviews the advent of human induced pluripotent stem cell (hiPSC) technology and introduces two major methods, “directed differentiation” and “neuronal induction,” by which it is now possible to generate neurons for modeling neuropsychiatric disease. Second, it discusses the recent applications, and the limitations, of these technologies to in vitro studies of psychiatric disorders.


2018 ◽  
Author(s):  
Eric Deneault ◽  
Muhammad Faheem ◽  
Sean H. White ◽  
Deivid C. Rodrigues ◽  
Song Sun ◽  
...  

AbstractInduced pluripotent stem cell (iPSC)-derived cortical neurons are increasingly used as a model to study developmental aspects of Autism Spectrum Disorder (ASD), which is clinically and genetically heterogeneous. To study the complex relationship of rare (penetrant) variant(s) and common (weaker) polygenic risk variant(s) to ASD, “isogenic” iPSC-derived neurons from probands and family-based controls, for modeling, is critical. We developed a standardized set of procedures, designed to control for heterogeneity in reprogramming and differentiation, and generated 53 different iPSC-derived glutamatergic neuronal lines from 25 participants from 12 unrelated families with ASD (14 ASD-affected individuals, 3 unaffected siblings, 8 unaffected parents). Heterozygousde novo(7 families; 16p11.2,NRXN1,DLGAP2,CAPRIN1,VIP,ANOS1,THRA) and rare-inherited (2 families;CNTN5,AGBL4) presumed-damaging variants were characterized in ASD risk genes/loci. In three additional families, functional candidates for ASD (SET), and combinations of putative etiologic variants (GLI3/KIF21AandEHMT2/UBE2Icombinations in separate families), were modeled. We used a large-scale multi-electrode array (MEA) as our primary high-throughput phenotyping assay, followed by patch clamp recordings. Our most compelling new results revealed a consistent spontaneous network hyperactivity in neurons deficient forCNTN5orEHMT2.Our biobank of iPSC-derived neurons and accompanying genomic data are available to accelerate ASD research.


2020 ◽  
Author(s):  
Franck Potet ◽  
Defne E. Egecioglu ◽  
Paul W. Burridge ◽  
Alfred L. George

ABSTRACTGS-967 and eleclazine (GS-6615) are novel sodium channel inhibitors exhibiting antiarrhythmic effects in various in vitro and in vivo models. The antiarrhythmic mechanism has been attributed to preferential suppression of late sodium current (INaL). Here, we took advantage of a throughput automated electrophysiology platform (SyncroPatch 768PE) to investigate the molecular pharmacology of GS-967 and eleclazine on peak sodium current (INaP) recorded from human induced pluripotent stem cell (hiPSC)-derived cardiomyocytes. We compared GS-967 and eleclazine to the antiarrhythmic drug lidocaine, the prototype INaL inhibitor ranolazine, and the slow inactivation enhancing drug lacosamide. In human induced pluripotent stem cell-derived cardiomyocytes, GS-967 and eleclazine caused a reduction of INaP in a frequency-dependent manner consistent with use-dependent block (UDB). GS-967 and eleclazine had similar efficacy but evoked more potent UDB of INaP (IC50=0.07 and 0.6 μM, respectively) than ranolazine (7.8 μM), lidocaine (133.5 μM) and lacosamide (158.5 μM). In addition, GS-967 and eleclazine exerted more potent effects on slow inactivation and recovery from inactivation compared to the other sodium channel blocking drugs we tested. The greater UDB potency of GS-967 and eleclazine was attributed to the significantly higher association rates (KON) and moderate unbinding rate (KOFF) of these two compounds with sodium channels. We propose that substantial UDB contributes to the observed antiarrhythmic efficacy of GS-967 and eleclazine.SIGNIFICANCE STATEMENTWe investigated the molecular pharmacology of GS-967 and eleclazine on sodium channels in human induced pluripotent stem cell derived cardiomyocytes using a high throughput automated electrophysiology platform. Sodium channel inhibition by GS-967 and eleclazine has unique features including accelerating the onset of slow inactivation and impairing recovery from inactivation. These effects combined with rapid binding and moderate unbinding kinetics explain potent use-dependent block, which we propose contributes to their observed antiarrhythmic efficacy.


2020 ◽  
Author(s):  
Jerome Robert ◽  
Nicholas Weilinger ◽  
Li-Ping Zao ◽  
Stefano Cataldi ◽  
Emily Button ◽  
...  

Abstract Introduction: The neurovascular unit (NVU) – the interaction between the neurons and the cerebrovasculature – is increasingly important to interrogate through human-based experimental models. Although advanced models of cerebral capillaries have been developed in the last decade, there is currently noin vitro3-dimensional (3D) perfusible model of the human cortical arterial NVU. Method: We used a tissue-engineering technique to develop a scaffold-directed, perfusible, 3D human NVU that is cultured in native-like flow conditions that mimics the anatomy and physiology of cortical penetrating arteries. Results: This system, composed of primary human vascular cells (endothelial cells, smooth muscle cells and astrocytes) and induced pluripotent stem cell (iPSC) derived neurons, demonstrates a physiological multilayer organization of the involved cell types. It also reproduces key characteristics of cortical neurons and astrocytes, as well as the formation of a selective and functional endothelial barrier. We further provide proof-of-principle that our in vitro human arterial NVU may be suitable to study neurodegenerative diseases such as Alzheimer’s disease (AD), as we report both phosphorylated tau and beta-amyloid accumulation in our model over time. Finally, we show that our arterial NVU model enables the study of neuronal and glial fluid biomarkers. Conclusion: This model is a suitable tool to investigate arterial NVU functions such as neuronal electrophysiology in health and disease. Further the design of platform allows culture under native-like flow conditions for extended periods of time and yields sufficient tissue and media for downstream immunohistochemistry and biochemistry analyses.


2020 ◽  
Author(s):  
Jerome Robert ◽  
Nicholas Weilinger ◽  
Li-Ping Zao ◽  
Stefano Cataldi ◽  
Emily Button ◽  
...  

Abstract Introduction: The neurovascular unit (NVU) – the interaction between the neurons and the cerebrovasculature – is increasingly important to interrogate through human-based experimental models. Although advanced models of cerebral capillaries have been developed in the last decade, there is currently no in vitro 3-dimensional (3D) perfusible model of the human cortical arterial NVU.Method: We used a tissue-engineering technique to develop a scaffold-directed, perfusible, 3D human NVU that is cultured in native-like flow conditions that mimics the anatomy and physiology of cortical penetrating arteries.Results: This system, composed of primary human vascular cells (endothelial cells, smooth muscle cells and astrocytes) and induced pluripotent stem cell (iPSC) derived neurons, demonstrates a physiological multilayer organization of the involved cell types. It reproduces key characteristics of cortical neurons and astrocytes and enables formation of a selective and functional endothelial barrier. We provide proof-of-principle data showing that this in vitro human arterial NVU may be suitable to study neurovascular components of neurodegenerative diseases such as Alzheimer’s disease (AD), as endogenously produced phosphorylated tau and beta-amyloid accumulate in the model over time. Finally, neuronal and glial fluid biomarkers relevant to neurodegenerative diseases are measurable in our arterial NVU model.Conclusion: This model is a suitable research tool to investigate arterial NVU functions in healthy and disease states. Further, the design of the platform allows culture under native-like flow conditions for extended periods of time and yields sufficient tissue and media for downstream immunohistochemistry and biochemistry analyses.


2020 ◽  
Author(s):  
Cameron Sadegh ◽  
Wataru Ebina ◽  
Anthony C. Arvanites ◽  
Lance S. Davidow ◽  
Lee L. Rubin ◽  
...  

AbstractDuring late embryonic development of the cerebral cortex, the major class of cortical output neurons termed subcerebral projection neurons (SCPN; including the predominant population of corticospinal neurons, CSN) and the class of interhemispheric callosal projection neurons (CPN) initially express overlapping molecular controls that later undergo subtype-specific refinements. Such molecular refinements are largely absent in heterogeneous, maturation-stalled, neocortical-like neurons (termed “cortical” here) spontaneously generated by established embryonic stem cell (ES) and induced pluripotent stem cell (iPSC) differentiation. Building on recently identified central molecular controls over SCPN development, we used a combination of synthetic modified mRNA (modRNA) for Fezf2, the central transcription factor controlling SCPN specification, and small molecule screening to investigate whether distinct chromatin modifiers might complement Fezf2 functions to promote SCPN-specific differentiation by mouse ES (mES)-derived cortical-like neurons. We find that the inhibition of a specific histone deacetylase, Sirtuin 1 (SIRT1), enhances refinement of SCPN subtype molecular identity by both mES-derived cortical-like neurons and primary dissociated E12.5 mouse cortical neurons. In vivo, we identify that SIRT1 is specifically expressed by CPN, but not SCPN, during late embryonic and postnatal differentiation. Together, these data indicate that SIRT1 has neuronal subtype-specific expression in the mouse cortex in vivo, and its inhibition enhances subtype-specific differentiation of highly clinically relevant SCPN / CSN cortical neurons in vitro.


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