Biology subjects

Kotter, M.

Publications and source records attributed to Kotter, M..

3 recordsLinked to original sources

bioRxiv2026

Assessing the impact of mono- and bi-allelic deletions in NRXN1 on synaptic function

Neurexin 1 (NRXN1) is an adhesion protein involved in synapse development and function. Mutations in NRXN1 are strongly linked with neurodevelopmental and psychiatric conditions. Mono-allelic NRXN1 mutations are associated with autistic traits, with increased likelihood of co-occurring intellectual disability. However, mono-allelic mutations have variable penetrance and occur in individuals without neurodevelopmental phenotypes. Conversely, bi-allelic mutations, though rarer, are associated with more stable penetrance and severe neurodevelopmental phenotypes. Human induced pluripotent stem cells (iPSC) have been used to study how mutations in NRXN1 impacts its function, with most studies focusing on monoallelic mutations. In this study, we systematically compared monoallelic and biallelic mutations in NRXN1, characterising their effects on molecular, synaptic, and functional phenotypes. Using CRISPR-Cas9, we introduced indels in NRXN1 exon 19, in an iPSC line containing inducible NGN2. These edits caused either mono-allelic or compound bi-allelic frameshift mutations. iPSCs containing either mutation robustly generated glutamatergic neurons, but these neurons displayed reduced expression of major NRXN1 isoforms. Transcriptomic profiling revealed modest gene expression changes in mono-allelic mutant neurons, whereas bi-allelic mutants exhibited extensive dysregulation of gene networks associated with neuronal maturation and synaptic function. Furthermore, synaptic phenotypes were mild in mono-allelic mutants but pronounced in bi-allelic mutant neurons. Both mono-allelic and bi-allelic mutant neurons displayed alterations in neuronal network activity and reduced peak depolarisation responses to KCl stimulation. Together, these data demonstrate that NRXN1 exhibits gene-dosage sensitivity, with bi-allelic disruption of exon 19 unmasking molecular, synaptic, and functional phenotypes that are only modest in mono-allelic mutant neurons.

neuroscience↗

bioRxiv2025

Drug treatment alters performance in a neural microphysiological system of information processing

Assessment of pharmacological intervention on in vitro neural systems often emphasizes molecular and structural changes. However, neural systems fundamentally process and act on information. For preclinical assays to predict drug efficacy, they must model these physiological functions. DishBrain, an in vitro synthetic biological intelligence (SBI) assay embodying a neural system in a simulated game-world, enables the quantification of this information-processing capacity, however the question remains whether such a system permits classical pharmacological interrogation and dose-response profiling. Hyperactive glutamatergic dysregulation is linked to neurological disorders including epilepsy, and inducible overexpression of neurogenin 2 (NGN2) in human induced pluripotent stem cells (hiPSCs) generates glutamatergic cultures with dysregulated hyperactivity. We therefore tested three anti-seizure medications (ASMs), phenytoin, perampanel, and carbamazepine, on NGN2 neurons from day 21 of differentiation in this system. The key finding was that, while all compounds altered spontaneous firing, carbamazepine 200 {micro}M significantly improved gameplay metrics. This marks the first demonstration of altered SBI following exogenous drug treatment. Notably, only inhibitory compounds enhanced goal-directed activity, linking glutamatergic attenuation to performance. Neurocomputational analysis revealed nuanced pharmacological responses during closed-loop stimulation, highlighting insights beyond spontaneous activity metrics.

neuroscience↗

bioRxiv2024

Circadian clocks in human cerebral organoids

Circadian rhythms result from cell-intrinsic timing mechanisms that impact health and disease1,2. To date, however, neural circadian research has largely focused on the hypothalamic circuitry of nocturnal rodents3. Whether circadian rhythms exist in human brain cells is unknown. Here we show bona fide circadian rhythms in human neurons, glia, cerebral organoids, and cerebral organoid slices (ALI-COs)4-8. Human neural circadian rhythms are synchronised by physiological timing cues such as glucocorticoids and daily temperature cycles, and these rhythms are temperature-compensated across the range of normal human brain temperatures9. Astrocyte rhythms are phase-advanced relative to other cultures and they modulate neuronal clock responses to temperature shift. Cerebral organoid rhythms are more robust at physiological brain temperatures; the relative amplitude of these rhythms increases over time in culture and their resetting capacity recapitulates key neurodevelopmental transitions in glucocorticoid signalling10-14. Remarkably, organoid post-transcriptional bioluminescent clock reporter rhythms are retained even when those of their putative transcriptional drivers are indiscernible15, and electrophysiology recordings confirm circadian rhythms in functional activity of monocultures, organoids, and ALI-COs. Around one third of the cerebral organoid proteome and phosphoproteome are circadian-rhythmic, with temporal consolidation of disease-relevant neural processes. Finally, we show that human brain organoid rhythms can be modulated and disrupted by commonly used brain-permeant drugs and mistimed cortisol exposure, respectively. Our results demonstrate that human brain cells and tissues develop their own circadian oscillations and that canonical mechanisms of the circadian clockwork may be inadequate to explain these rhythmic phenomena. 2D and 3D human neural cultures represent complementary and tractable models for exploring the emergence, disruption, and mechanics of the circadian neural clockwork, with important implications for chronobiology, brain function, and brain health.

neuroscience↗