Biology subjects

Heiland, M.

Publications and source records attributed to Heiland, M..

5 recordsLinked to original sources

bioRxiv2026

CDKL5 deficiency alters cell subtype-specific molecular programmes and intercellular signalling in the mouse hippocampus

CDKL5 deficiency disorder (CDD) is a severe neurodevelopmental condition characterised by epilepsy, intellectual disability, and motor dysfunction. Loss of CDKL5 leads to altered synapse development, excitatory-inhibitory imbalances and glial changes, but the underlying molecular mechanisms remain incompletely understood, particularly at the level of individual brain cell subtypes. Here, we performed single-nucleus RNA sequencing (snRNA-seq) on the hippocampus of 12 weeks old heterozygous female Cdkl5 exon 6 deletion (Cdkl5tm1.1Joez/J) and wild-type mice to characterise cell-subtype-specific transcriptional alterations associated with CDKL5 deficiency. Analysis of 11,791 high-quality nuclei revealed cell-subtype-specific transcriptional changes across neuronal and non-neuronal populations. Differential expression was most prominent in intratelencephalic and extratelencephalic (IT-ET) glutamatergic neurons, which showed altered expression of genes involved in neuronal signalling and activity-dependent transcription, and in dentate gyrus (DG) neurons, which exhibited coordinated upregulation of multiple ribosomal protein genes. Gene set enrichment analysis revealed broader molecular alterations, with neuronal populations showing recurrent changes in pathways associated with synaptic organisation, neuronal development, axonal and dendritic processes, and neurotransmission. Altered gene expression was also evident among non-neuronal populations, although these displayed fewer changes. CellChat analysis inferred changes in predicted intercellular communication across excitatory and inhibitory neuronal populations, particularly Sema3c signalling, suggesting reorganization of hippocampal neuronal subtypes. These findings provide a single-nucleus transcriptional atlas of the hippocampus in a CDD mouse model. In our dataset, CDKL5 deficiency was associated with cell-subtype-specific alterations in gene expression, including enrichment of gene pathways related to cellular metabolism, neuronal development and synaptic organisation, alongside alteration in predicted intercellular signalling. This dataset provides a resource for investigating the cellular and molecular mechanisms underlying CDD and for prioritising candidate pathways for future therapeutic investigation.

neuroscience↗

bioRxiv2025

Attenuated single neuron and network hyperexcitability following microRNA-134 inhibition in mice with drug-resistant temporal lobe epilepsy

The multi-factorial pathophysiology of acquired epilepsies lends itself to a multi-targeting therapeutic approach. MicroRNAs (miRNA) are short noncoding RNAs that individually can negatively regulate dozens of protein-coding transcripts. Previously, we reported that central injection of antisense oligonucleotides targeting microRNA-134 (Ant-134) shortly after status epilepticus potently suppressed the development of recurrent spontaneous seizures in rodent models of temporal lobe epilepsy. The mechanism(s) of these anti-seizure effects remain, however, incompletely understood. Here we show that intracerebroventricular microinjection of Ant-134 in male mice with pre-existing epilepsy caused by intraamygdala kainic acid-induced status epilepticus potently reduces the occurrence of spontaneous seizures. Recordings from ex vivo brain slices collected 2-4 days after Ant-134 injection in epileptic mice, detected a number of electrophysiological phenotypic changes consistent with reduced excitability. Specifically, Ant-134 reduced action potential bursts after current injection in CA1 neurons and reduced miniature excitatory post-synaptic current frequencies in CA1 neurons. Ant-134 also reduced general network excitability, including attenuating pro-excitatory CA1 responses to Schaffer collateral stimulation in hippocampal slices from epileptic mice. Together, the present study demonstrates inhibiting miR-134 reduces single neuron and network hyperexcitability in mice and extends support for this approach to treat drug-resistant epilepsies. Significance statementTemporal lobe epilepsy is one of the most common forms of drug-resistant epilepsy. Identifying molecular regulators of enduring states of hyperexcitability may lead to new therapeutic approaches. MicroRNAs are short noncoding RNAs that act post-transcriptionally to lower levels of sets of protein-coding genes. Here we show that inhibiting miR-134 reduces spontaneous seizures in mice with active epilepsy. Electrophysiologic recordings from brain slices collected when mice were transitioning to fewer seizures revealed changes to both single neuron and inter-regional communication properties that may explain the reduction in hippocampal network excitability. The findings support the development of this microRNA-targeting approach for epilepsy.

neuroscience↗

bioRxiv2023

Brain cell-specific origin of circulating microRNA biomarkers in experimental temporal lobe epilepsy

The diagnosis of epilepsy is complex and challenging and would benefit from the availability of molecular biomarkers, ideally measurable in a biofluid such as blood. Experimental and human epilepsy are associated with altered brain and blood levels of various microRNAs (miRNAs). Evidence is lacking, however, as to whether any of the circulating pool of miRNAs originates from the brain. To explore the link between circulating miRNAs and the pathophysiology of epilepsy, we first sequenced argonaute 2 (Ago2)-bound miRNAs in plasma samples collected from mice subject to status epilepticus induced by intraamygdala microinjection of kainic acid. This identified time-dependent changes in plasma levels of miRNAs with known neuronal and microglial-cell origins. To explore whether the circulating miRNAs had originated from the brain, we generated mice expressing FLAG-Ago2 in neurons or microglia using tamoxifen-inducible Thy1 or Cx3cr1 promoters, respectively. FLAG immunoprecipitates from the plasma of these mice after seizures contained miRNAs, including let-7i-5p and miR-19b-3p. Taken together, these studies confirm that a portion of the circulating pool of miRNAs in experimental epilepsy originates from the brain, increasing support for miRNAs as mechanistic biomarkers of epilepsy.

neuroscience↗

bioRxiv2022

MicroRNA-335-5p suppresses voltage-gated sodium channel expression and may be a target for seizure control

There remains an urgent need for new therapies for drug-resistant epilepsy (DRE). Sodium channel blockers are effective for seizure control in common forms of epilepsy, but loss of sodium channel function underlies some genetic forms of epilepsy. Approaches that provide bi-directional control of sodium channel expression are needed. MicroRNAs (miRNA) are small non-coding RNAs which negatively regulate gene expression. Here, we show that genome-wide miRNA screening of hippocampal tissue from a rat epilepsy model, mice treated with the novel anti-seizure medicine cannabidiol (CBD) and plasma from patients with DRE, converge on a single target, miR-335-5p. Pathway analysis on predicted and validated miR-335-5p targets identified multiple voltage-gated sodium channels (VGSCs). Intracerebroventricular injection of antisense oligonucleotides against miR-335-5p resulted in upregulation of Scn1a, Scn2a and Scn3a in the mouse brain and an increased action potential rising phase and greater excitability of hippocampal pyramidal neurons in brain slice recordings, consistent with VGSCs as functional targets of miR-335-5p. Blocking of miR-335-5p also increased voltage-gated sodium currents in human iPSC-derived neurons. Inhibition of miR-335-5p increased susceptibility to tonic-clonic seizures in the pentylenetetrazole seizure model, whereas AAV9-mediated overexpression of miR-335-5p reduced seizure severity and improved survival. These studies suggest modulation of miR-335-5p may be a means to regulate VGSCs and affect brain excitability and seizures. Changes to miR-335-5p may reflect compensatory mechanisms to control excitability and could provide new biomarker or therapeutic strategies for different types of drug-resistant epilepsy. Significance StatementDespite the clinical availability of over 30 anti-seizure medications (ASMs), around 30% of people with epilepsy do not achieve seizure freedom. MicroRNAs are small non-coding RNAs which negatively regulate protein expression by binding to target mRNAs. Here, we identified the brain-enriched miR-335-5p to be commonly altered in three heterogenous miRNA profiling datasets. Bi-directional modulation of miR-335-5p identified a potential homeostatic role of miR-335-5p in brain excitability involving voltage-gated sodium channels. Electrophysiological and in vivo approaches revealed pro-epileptic activity of miR-335-5p inhibition whereas overexpression of miR-335-5p resulted in anti-epileptic activity. Overall, targeting miR-335-5p could provide a new approach in the modulation of brain excitability, with possible therapeutic applications in drug-resistant epilepsies and other neurological diseases.

neuroscience↗

bioRxiv2019

Slow and fast cortical dynamics distinguish motor planning and execution

The smooth conduction of movements requires simultaneous motor planning and execution according to internal goals. So far it is not known how such movement plans can be modified without being distorted by ongoing movements. Previous studies have isolated planning and execution related neuronal activity by separating behavioral planning and movement periods in time by sensory cues1-7. Here, we introduced two novel tasks in which motor planning developed intrinsically. We separated this continuous self-paced motor planning statistically from motor execution by experimentally minimizing the repetitiveness of the movements. Thereby, we found that in the rat sensorimotor cortex, neuronal motor planning processes evolved with slower dynamics than movement related responses both on a sorted unit and population level. The fast evolving neuronal activity preceded skilled forelimb movements while it coincided with movements in a locomotor task. We captured this fast evolving movement related activity via a high-pass filter approach and confirmed the results with optogenetic stimulations. As biological mechanism underlying such a high pass filtering we suggest neuronal adaption. The differences in dynamics combined with a high pass filtering mechanism represents a simple principle for concurrent motor planning and execution in which planning will result in relatively slow dynamics that will not produce movements.

neuroscience↗