Biology subjects

Lüthi, A.

Publications and source records attributed to Lüthi, A..

9 recordsLinked to original sources

bioRxiv2026

The cell cycle regulates cell-penetrating peptide cytosolic uptake via differential expression of KCNH1 potassium channel

Membrane potential fluctuations, driven by ion channel activity, are important regulators of processes such as action potential propagation in neurons and muscle cell contraction. These variations also occur in non-excitable cells, influencing various cellular processes, including, but not limited to, direct translocation of cell-penetrating peptides (CPPs) into the cytosol. CPPs are cationic peptide vectors that facilitate the delivery of cargos into cells. The efficiency of CPP direct translocation varies significantly within the same cell population, a phenomenon that is not understood mechanistically. In this study, we used an unbiased transcriptomic approach to identify genes involved in efficient CPP cytosolic uptake. This revealed a close correlation between the expression of cell cycle-related genes and the ability of cells to take up CPPs by direct translocation. Monitoring phases of the cell cycle with the PIP-FUCCI system showed that CPP direct translocation was most efficient in the G2/M and S phases and least efficient during the G1 phase. This was correlated with the cells plasma membrane potential: cells in G2/M and S phases being more polarized than cells in the G1 phase. The expression of the KCNH1 voltage-gated potassium channel was found to be highest in the phases of the cell cycle most permissive for CPP direct translocation. Pharmacological inhibition of KCNH potassium channels efficiently blocked CPP direct translocation in these cell cycle phases. These data indicate that KCNH1 controls the cell membrane potential in a cell cycle-dependent manner and consequently the ability of cells to take up CPPs by direct translocation. Our findings highlight the importance of the cell cycle in regulating CPP uptake. Variations in the plasma membrane potential along the cell cycle should be considered in the development of CPP-based therapeutics and their applications.

cell biology↗

bioRxiv2025

A common neuronal basis for Pavlovian and instrumental learning in amygdala circuits

Reward-predictive Pavlovian cues can selectively invigorate instrumental behaviors. Accumulating evidence pinpoints the basolateral amygdala (BLA) as a key brain structure to assign outcome-specific motivational significance to Pavlovian cues or Instrumental actions. However, whether neuronal representations of Pavlovian and Instrumental learnings are processed in different BLA circuits and how the resulting memories interact is unknown. Here, we used calcium imaging and optogenetic manipulation of the BLA neurons in mice that acquired and expressed Pavlovian and Instrumental behaviors in a multi-phase behavioral task called specific Pavlovian to Instrumental Transfer (sPIT). We first confirmed that Pavlovian cues selectively invigorate instrumental actions and showed that this effect, referred as the sPIT effect, depends on BLA activity. Then, by tracking the activity of single BLA neurons across days, we found that BLA neurons integrate common reward-anticipation information relevant for Pavlovian and instrumental learning. Interestingly, this reward-anticipation information re-emerged during subsequent memory transfer and covaried with sPIT effect. These findings reveal that the BLA encodes an outcome-specific motivational state that generalizes across Pavlovian and instrumental behaviors to promote and guide reward-seeking behavior.

neuroscience↗

bioRxiv2024

Heterogeneous plasticity of amygdala interneurons in associative learning and extinction

Neural circuits undergo experience-dependent plasticity to form long-lasting memories. Excitatory projection neurons are considered to be the primary neuronal substrate for memory acquisition and storage. However, inhibitory interneurons control the activity of projection neurons in a in a spatially and temporally precise manner, yet their contribution to memory acquisition, storage and expression remains poorly understood. Here, we employ a miniature microscope imaging approach to monitor the activity of large amygdala interneuron populations in freely moving mice during fear learning and extinction at the single cell level. We find that amygdala interneurons display mixed-selectivity and show complex plastic responses at both the ensemble and single neuron level across the acquisition, expression and extinction of aversive memories. In contrast to bidirectional single cell plasticity across distinct fear states, learning-induced changes at the population level occur transiently during conditioning and do not consolidate across days. Examining molecular interneuron subpopulations revealed that disinhibitory vasoactive intestinal peptide (VIP) expressing cells are predominantly activated by high fear states. In contrast, somatostatin (SST) interneurons display a preference for safety cues and thereby suppress excitatory neuron responsiveness. However, responses of individual neurons within the SST and VIP populations are non-uniform, indicating the presence of functional subtypes within classical molecularly-defined interneuron populations. Taken together, we identify complex neuronal plasticity within amygdala interneuron ensembles that goes beyond a passive processing function, suggesting a critical role of inhibitory microcircuit elements for memory selectivity and stability.

neuroscience↗

bioRxiv2023

Homeostatic regulation of REM sleep by the preoptic area of the hypothalamus

Rapid-eye-movement sleep (REMs) is characterized by activated electroencephalogram (EEG) and muscle atonia, accompanied by vivid dreams. REMs is homeostatically regulated, ensuring that any loss of REMs is compensated by a subsequent increase in its amount. However, the neural mechanisms underlying the homeostatic control of REMs are largely unknown. Here, we show that GABAergic neurons in the preoptic area of the hypothalamus projecting to the tuberomammillary nucleus (POAGAD2[->]TMN neurons) are crucial for the homeostatic regulation of REMs. POAGAD2[->]TMN neurons are most active during REMs, and inhibiting them specifically decreases REMs. REMs restriction leads to an increased number and amplitude of calcium transients in POAGAD2[->]TMN neurons, reflecting the accumulation of REMs pressure. Inhibiting POAGAD2[->]TMN neurons during REMs restriction blocked the subsequent rebound of REMs. Our findings reveal a hypothalamic circuit whose activity mirrors the buildup of homeostatic REMs pressure during restriction and that is required for the ensuing rebound in REMs.

neuroscience↗

bioRxiv2023

Pupil size reveals arousal level dynamics in human sleep

Recent animal research has revealed the intricate dynamics of arousal levels that are potentially crucial for maintaining proper sleep resilience and memory consolidation. Also in humans, changes in arousal level are believed to be a determining characteristic of healthy and pathological sleep but tracking arousal fluctuations has been methodologically challenging. Here we measured pupil size, an established indicator of arousal levels, during overnight sleep and tested whether the arousal level affects cortical response to auditory stimulation. We show that pupil size dynamics change as a function of sleep macrostructure and microstructural events. In particular, pupil size is inversely related to the occurrence of sleep spindle clusters, a marker of sleep resilience. Additionally, pupil size prior to auditory stimulation influences the evoked response, most notably in delta power, a marker of several restorative and regenerative functions of sleep. Recording pupil size dynamics provides novel insights into the interplay between arousal levels and sleep oscillations, opening new avenues for future research and clinical applications in diagnosing and treating pathological sleep associated with abnormal arousal levels.

neuroscience↗

bioRxiv2022

Multimodal mapping of cell types and projections in the central nucleus of the amygdala

The central nucleus of the amygdala (CEA) is a brain region that integrates external and internal sensory information and executes innate and adaptive behaviors through distinct output pathways. Despite its complex functions, the diversity of molecularly defined neuronal types in the CEA and their contributions to major axonal projection targets have not been examined systematically. Here, we performed single-cell RNA-sequencing (scRNA-Seq) to classify molecularly defined cell types in the CEA and identified marker-genes to map the location of these neuronal types using expansion assisted iterative fluorescence in situ hybridization (EASI-FISH). We developed new methods to integrate EASI-FISH with 5-plex retrograde axonal labeling to determine the spatial, morphological, and connectivity properties of [~]30,000 molecularly defined CEA neurons. Our study revealed spatio-molecular organization of the CEA, with medial and lateral CEA associated with distinct cell families. We also found a long-range axon projection network from the CEA, where target regions receive inputs from multiple molecularly defined cell types. Axon collateralization was found primarily among projections to hindbrain targets, which are distinct from forebrain projections. This resource reports marker-gene combinations for molecularly defined cell types and axon-projection types, which will be useful for selective interrogation of these neuronal populations to study their contributions to the diverse functions of the CEA.

neuroscience↗

bioRxiv2021

Cortico-autonomic local arousals and heightened somatosensory arousability during NREM sleep of mice in neuropathic pain

Chronic pain patients frequently suffer from sleep disturbances. Improvement of sleep quality alleviates pain, but neurophysiological mechanisms underlying sleep disturbances require clarification to advance therapeutic strategies. Chronic pain causes high-frequency electrical activity in pain-processing cortical areas that could disrupt the normal process of low-frequency sleep rhythm generation. We found that the spared-nerve-injury (SNI) mouse model, mimicking human neuropathic pain, had preserved sleep-wake behavior. However, when we probed spontaneous arousability based on infraslow continuity-fragility dynamics of non-rapid-eye-movement sleep (NREMS), we found more numerous local cortical arousals accompanied by heart rate increases in hindlimb primary somatosensory, but not in prelimbic, cortices of SNI mice. Closed-loop mechanovibrational stimulation revealed higher sensory arousability in SNI. Sleep in chronic pain thus looked preserved in conventional measures but showed elevated spontaneous and evoked arousability. Our findings develop a novel moment-to-moment probing of NREMS fragility and propose that chronic pain-induced sleep complaints arise from perturbed arousability.

physiology↗

bioRxiv2018

Amygdala neuronal ensembles dynamically encode behavioral states

Internal states, including affective or homeostatic states, are important behavioral motivators. The amygdala is a key brain region involved in the regulation of motivated behaviors, yet how distinct internal states are represented in amygdala circuits is unknown. Here, by imaging somatic neural calcium dynamics in freely moving mice, we identify changes in the relative activity levels of two major, non-overlapping populations of principal neurons in the basal nucleus of the amygdala (BA) that predict switches between exploratory and non-exploratory (defensive, anxiety-like) behavioral states across different environments. Moreover, the amygdala widely broadcasts internal state information via several output pathways to larger brain networks, and sensory responses in BA occur independently of behavioral state encoding. Thus, the brain processes external stimuli and internal states in an orthogonal manner, which may facilitate rapid and flexible selection of appropriate, state-dependent behavioral responses.

neuroscience↗

bioRxiv2017

Central Amygdala Circuits Modulate Food Consumption Through A Positive Valence Mechanism

The complex behaviors underlying the pursuit and consumption of rewards are integral to an organisms survival. The hypothalamus and mesolimbic dopamine system are key mediators of these behaviors, yet regulation of appetitive and consummatory behaviors outside of these regions is not well understood. The central nucleus of the amygdala (CeA) is implicated in feeding and reward behavior, but the specific neural players and circuit mechanisms that positively regulate these behaviors remain unclear. Here, we define the neuronal mechanisms by which the CeA promotes consumption of food. We show, using in vivo activity manipulations and Ca2+ imaging, that CeA GABAergic neurons expressing the serotonin receptor 2a (Htr2a) modulate food consumption in multiple contexts, promote positive reinforcement and are active in vivo during eating. We demonstrate using electrophysiology, anatomical tracing methods and in vivo optogenetics that both intra-CeA and long-range circuit mechanisms underlie these functional effects. Finally, we show that CeAHtr2a neurons are poised to regulate food consumption through inputs from feeding-relevant brain regions. Our study highlights a mechanism by which defined CeA neural circuits positively regulate food consumption.

neuroscience↗