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  3. Assessing neuroprotective effects of diroximel fumarate and siponimod via modulation of pacemaker channels in an experimental model of remyelination

Assessing neuroprotective effects of diroximel fumarate and siponimod via modulation of pacemaker channels in an experimental model of remyelination

  • Exp Neurol. 2023 Oct 16:114572. doi: 10.1016/j.expneurol.2023.114572.
Laura Vinnenberg 1,  Nicole Rychlik 2,  Tengiz Oniani 3,  Brandon Williams 4,  John A White 4,  Stjepana Kovac 1,  Sven G Meuth 5,  Thomas Budde 3,  Petra Hundehege 1
Affiliations

Affiliations

  • 1 Department of Neurology with Institute of Translational Neurology, Münster University, Albert-Schweitzer-Campus 1, D-48149 Münster, Germany.
  • 2 Institute of Physiology I, Münster University, Robert-Koch-Str. 27a, D-48149 Münster, Germany. Electronic address: [email protected].
  • 3 Institute of Physiology I, Münster University, Robert-Koch-Str. 27a, D-48149 Münster, Germany.
  • 4 Department of Biomedical Engineering, Center for Systems Neuroscience, Neurophotonics Center, Boston University, 610 Commonwealth Ave, Boston MA-02215, USA.
  • 5 Neurology Clinic, Medical Faculty, University Clinic Düsseldorf, Moorenstraße 5, D-40225 Düsseldorf, Germany.
PMID: 37852467 DOI: 10.1016/j.expneurol.2023.114572
Abstract

Cuprizone (CPZ)-induced alterations in axonal myelination are associated with a period of neuronal hyperexcitability and increased activity of hyperpolarization-activated and cyclic nucleotide-gated (HCN) channels in the thalamocortical (TC) system. Substances used for the treatment of multiple sclerosis (MS) have been shown to normalize neuronal excitability in CPZ-treated mice. Therefore, we aimed to examine the effects of diroximel fumarate (DRF) and the sphingosine 1-phospate receptor (S1PR) modulator siponimod on action potential firing and the inward current (Ih) carried by HCN ion channels in naive conditions and during different stages of de- and remyelination. Here, DRF application reduced Ih current density in ex vivo patch clamp recordings from TC neurons of the ventrobasal thalamic complex (VB), thereby counteracting the increase of Ih during early remyelination. Siponimod reduced Ih in VB neurons under control conditions but had no effect in neurons of the auditory cortex (AU). Furthermore, siponimod increased and decreased AP firing properties of neurons in VB and AU, respectively. Computational modeling revealed that both DRF and siponimod influenced thalamic bursting during early remyelination by delaying the onset and decreasing the interburst frequency. Thus, substances used in MS treatment normalize excitability in the TC system by influencing AP firing and Ih.

Keywords

Auditory cortex; Computational modeling; Cuprizone model; Dimethyl fumarate; HCN channel; Ion channel; Multiple sclerosis; Siponimod; Thalamus.

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