Career Center AES Connect

Abstracts

Stem-cell Derived Neurons of KCNQ2 Developmental and Epileptic Encephalopathy Reveal a Profound Developmental Delay Starting Early After Neurogenesis

Abstract number : 1.236
Submission category : 2. Translational Research / 2D. Models
Year : 2024
Submission ID : 736
Source : www.aesnet.org
Presentation date : 12/7/2024 12:00:00 AM
Published date :

Authors :
Presenting Author: Filip Rosa, MD – Dept. of Neurology and Epileptology, Hertie Center for Neurology & Hertie Institute for Clinical Brain Research, University and University Hospital Tübingen, Tübingen, Germany

Stephan Theiss, Dipl.-Phys. – Institute of Clinical Neuroscience and Medical Psychology, Medical Faculty and University Hospital Düsseldorf, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
Susanne Krepp, MD – Dept. of Neurology and Epileptology, Hertie Center for Neurology & Hertie Institute for Clinical Brain Research, University and University Hospital Tübingen, Tübingen, Germany
Heidi Loeffler, Ms. – Dept. of Neurology and Epileptology, Hertie Center for Neurology & Hertie Institute for Clinical Brain Research, University and University Hospital Tübingen, Tübingen, Germany
Dulini Mendes, PhD – The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia
Stefanie Klingenstein, PhD – Institute of Neuroanatomy and Developmental Biology (INDB), Eberhard Karls University Tübingen, Tübingen, Germany
Stefan Liebau, MD – Institute of Neuroanatomy and Developmental Biology (INDB), Eberhard Karls University Tübingen, Tübingen, Germany
Sarah Weckhuysen, MD, PhD – Neurogenetics Group, Center for Molecular Neurology, VIB, Antwerp, Belgium
Michael Alber, MD – Pediatric Neurology and Developmental Medicine, University of Tübingen, Tübingen, Germany
Steven Petrou, PhD – Praxis Precision Medicines, Boston, MA, USA
Holger Lerche, MD – Dept. of Neurology and Epileptology, Hertie Center for Neurology & Hertie Institute for Clinical Brain Research, University and University Hospital Tübingen, Tübingen, Germany
Snezana Maljevic, PhD – Florey Institute of Neuroscience and Mental Health, University of Melbourne, Australia
Thomas Wuttke, MD – Dept. of Neurology and Epileptology, Hertie Center for Neurology & Hertie Institute for Clinical Brain Research, University and University Hospital Tübingen, Tübingen, Germany

Rationale: KCNQ2, encoding KV7.2 ion channels, has emerged as one of the prominent genes causing early onset seizures with developmental delay (KCNQ2 developmental and epileptic encephalopathy; KCNQ2-DEE). KCNQ2 de novo loss-of-function (LOF) and associated neuronal hyperexcitability have been accepted as mechanisms contributing to seizures. To investigate the developmental impact of KCNQ2 LOF, we generated patient iPSC-derived models for two previously reported de novo variants, p.(Arg325Gly) and p.(Gly315Arg), linked to severe congenital DEE.


Methods: Functional investigation of the two variants was initially performed in Xenopus laevis oocyte system. Patient-derived iPSC lines were differentiated using NGN2- and embryoid body-based protocols yielding neurons roughly corresponding to mid- and mid-late gestational stages, respectively. KV7-mediated M-current, passive neuronal properties, action potential generation and spontaneous oscillatory network activities were analysed with whole-cell patch clamping.


Results: We confirmed LOF of both variants in Xenopus laevis oocytes and demonstrated reduced KCNQ2-associated M-currents in patient-derived neurons. In contrast with previously identified hyperexcitability in mouse models of KCNQ2-DEE, we found reduced action potential firing and disrupted network activity patterns.


Conclusions: We provide experimental evidence for changing roles of the M-current throughout development and place disease variant-mediated M-current reduction in the context of the neuronal maturation in the prenatal brain. Based on the reduced neuronal firing and disrupted oscillatory activity seen in patient iPSC-derived neurons, we propose that a delayed/impaired maturation of neuronal and network properties underlies KCNQ-DEE caused by LOF variants.


Funding: This work was supported by the German Federal Ministry for Education and Research (BMBF): Rare disease networks IonNeurONet (01GM1105A to SM and HL) and Treat-ION (01GM2210A to HL) and via the European Joint Program on Rare Diseases (EJP-RD), TreatKCNQ (01GM2003B to TVW). FR was supported by the DAAD program (91529082) and Endeavour research fellowship program (6093_2017). We thank the patients and their parents for participating in the study.


Translational Research