Biology subjects

Beier, K.

Publications and source records attributed to Beier, K..

13 recordsLinked to original sources

bioRxiv2026

Primary Cilia Loss in Striatal Neurons Disrupts Synaptic Connectivity and Excitatory Transmission and Drives Metabolomic Remodeling

Disruption of striatal circuits is a central feature of many neurological and psychiatric disorders, yet the mechanisms that maintain afferent connectivity and synaptic function in striatal neurons remain incompletely defined. Primary cilia are signaling organelles present on almost all striatal medium spiny neurons that are enriched in neuromodulatory receptors, suggesting a role in coordinating striatal neuronal communication and biochemical state. Here, we show that conditional ablation of primary cilia from striatal neurons by AAV-Cre-mediated deletion of Ift88 disrupts the afferent connectivity, synaptic function, and chemical signature of the striatum. Monosynaptic rabies tracing revealed an approximately threefold reduction in brain-wide input convergence onto striatal neurons. Whole-cell recordings showed reduced miniature excitatory postsynaptic current amplitude and frequency together with a reduced NMDA:AMPA ratio, consistent with weakened glutamatergic synaptic transmission. Untargeted metabolomics revealed broad remodeling of the striatal chemical profile, predominantly toward decreased measured levels, with lipid-associated pathways most affected alongside reductions in polyamines, glutamate-related metabolites, and neuromodulatory, particularly excitatory, signaling molecules. By contrast, the cortex, which was not targeted by the AAV injection, showed fewer and directionally opposite molecular changes. These findings identify cilia as essential regulators of the structural, synaptic, and molecular integrity required for normal striatal circuit function.

neuroscience↗

bioRxiv2026

Kappa opioid receptors (KORs) in the anterior paraventricular nucleus of the thalamus (aPVT) mediate morphine withdrawal-, anxiety-, fear-, and KOR agonist-induced aversion-like behaviors in mice

PVT is involved in stress responses, fear, anxiety, arousal, aversion and reward. Anterior and posterior PVT (aPVT and pPVT) have different neuronal connections, molecular contents, and functional roles. PVT expressed a high level of KOR. Herein we mapped the projection targets of aPVT KOR(+) neurons and explored the behavioral significance of aPVT KOR. Using KOR-iCre mice and Cre-dependent anterograde tracer, we found that KOR(+) glutamatergic neurons in aPVT primarily projected to NAc, CeA, BNST, PFC, and reticular nucleus of the thalamus (RT). 3-D images showed the pathway emanating from aPVT to the ventral RT, through NAc, and out to the other regions, indicating widespread axonal collateralization. We conditionally knock-downed KOR (KOR cKD) in aPVT by injection of AAV-eGFP-Cre or AAV-eGFP (control) into aPVT of Oprk1lox/lox mice. [3H]U69,593 receptor autoradiography revealed substantial KOR cKD in aPVT. In both male and female mice, the KOR cKD in aPVT significantly reduced anxiety-like behaviors in the elevated plus-maze test, cue-induced freezing after fear conditioning and naloxone-precipitated morphine withdrawal-associated jumps. KOR cKD attenuated U50,488H-induced conditioned place aversion in males only, while having no effect on forced swim immobility or the U50,488H-induced visceral analgesic and antipruritic effects in either sex. Thus, our results reveal for the first time that KOR-mediated inhibition of aPVT neurons may mediate morphine withdrawal, anxiety, and cue-induced fear in both sexes but contribute to KOR agonist-induced aversion only in males. Notably, our findings reveal a previously unrecognized role for aPVT in regulating morphine withdrawal, acting in a manner distinct from pPVT.

neuroscience↗

bioRxiv2025

Multiplexed changes in synaptic transmission underlie stress-induced reduction of persistent firing in the parietal cortex

Repeated exposure to stress disrupts cognitive processes, including attention and working memory. A key mechanism supporting these functions is the ability of neurons to sustain action potential firing, even after a stimulus is no longer present. How stress impacts this persistent neuronal activity is currently unknown. We found that repeated exposure to multiple concurrent stressors during adolescence (aRMS) impedes the ability of layer 5 pyramidal neurons (L5 PNs) in the posterior parietal cortex (PPC) to produce persistent firing. To determine the mechanisms underlying this effect, we complemented computational modelling with whole-cell patch clamp electrophysiology in acute brain slices from male mice. Our model predicted that altered intrinsic excitability, reduced local connectivity, diminished glutamatergic transmission, or enhanced inhibition could explain diminished persistent activity. In ex vivo experiments, we found minimal effect of aRMS on excitability and recurrent connectivity. However, stress exposure altered the properties of excitatory connections between L5 PNs, specifically affecting decay kinetics and short-term synaptic dynamics. In addition, aRMS increased inhibitory tone in the PPC, altering both GABAa and GABAb receptor-mediated responses. Incorporating the observed physiological changes into our network model, we found that no single parameter was sufficient alone to reproduce the stress-induced reduction in persistent firing. Rather, a combination of altered excitatory and inhibitory synaptic transmission was necessary to impact sustained activity. These data suggest that a multitude of converging changes in neural and circuit function underpin the effects of stress on cognitive processes. HighlightsO_LIStress exposure impairs persistent firing in the posterior parietal cortex. C_LIO_LIGABAergic inhibition is enhanced following stress. C_LIO_LIStress alters excitatory transmission between layer 5 pyramidal cells. C_LIO_LICombined changes in inhibition and excitation impact persistent firing. C_LI

neuroscience↗

bioRxiv2025

Psilocybin triggers an activity-dependent rewiring of large-scale cortical networks

Psilocybin holds promise as a treatment for mental illnesses. One dose of psilocybin induces structural remodeling of dendritic spines in the medial frontal cortex in mice. The dendritic spines would be innervated by presynaptic neurons, but the sources of these inputs have not been identified. Here, using monosynaptic rabies tracing, we map the brain-wide distribution of inputs to frontal cortical pyramidal neurons. We discover that psilocybins effect on connectivity is network-specific: strengthening the routing of inputs from perceptual and medial regions (homolog of default mode network) to subcortical targets, while weakening inputs that are part of cortico-cortical recurrent loops. The pattern of synaptic reorganization depends on the drug-evoked spiking activity, because silencing a presynaptic region during psilocybin administration disrupts the rewiring. Collectively, the results reveal the impact of psilocybin on the connectivity of large-scale cortical networks and demonstrate neural activity modulation as an approach to sculpt the psychedelic-evoked neural plasticity.

neuroscience↗

bioRxiv2024

Rewiring oncogenic signaling to RNA vector replication for the treatment of metastatic cancer

Despite recent advances, improvements to long-term survival in metastatic carcinomas, such as pancreatic or ovarian cancer, remain limited. Current therapies suppress growth-promoting biochemical signals, ablate cells expressing tumor-associated antigens, or promote adaptive immunity to tumor neoantigens. However, these approaches are limited by toxicity to normal cells using the same signaling pathways or expressing the same antigens, or by the low frequency of neoantigens in most carcinomas. Here, we report a fundamentally different strategy for designing safer and more effective anti-cancer therapies through the sensing of cancer-driving biochemical signals and their rewiring to virotherapeutic activation. Specifically, we rationally engineer a RNA vector to self-replicate and cause cytotoxicity in cancer cells exhibiting hyperactive HER2 (ErbB2), but not in normal cells with normal HER2 signaling. Compared to a widely tested virotherapeutic from the same vector family, our hyperactive ErbB2-restricted RNA vector (HERV) exhibits lower toxicity and greater activity against metastatic HER2-positive ovarian cancer in mice, extending survival independently of tumor antigenicity. Most importantly, HERV synergizes with standard-of-care chemotherapy against ovarian cancer metastases in vivo, with 43% of combination-treated subjects surviving for months beyond subjects treated with either therapy alone. Taken together, these results introduce rewiring of cancer-driving signaling pathways to virotherapeutic activation as a strategy for more specific and effective cancer treatment.

synthetic biology↗

bioRxiv2024

Molecular and circuit determinants in the globus pallidus mediating control of cocaine-induced behavioral plasticity

The globus pallidus externus (GPe) is a central component of the basal ganglia circuit, receiving strong input from the indirect pathway and regulating a variety of functions, including locomotor output and habit formation. We recently showed that it also acts as a gatekeeper of cocaine-induced behavioral plasticity, as inhibition of parvalbumin-positive cells in the GPe (GPePV) prevents the development of cocaine-induced reward and sensitization. However, the molecular and circuit mechanisms underlying this function are unknown. Here we show that GPePV cells control cocaine reward and sensitization by inhibiting GABAergic neurons in the substantia nigra pars reticulata (SNrGABA), and ultimately, selectively modulating the activity of ventral tegmental area dopamine (VTADA) cells projecting to the lateral shell of the nucleus accumbens (NAcLat). A major input to GPePV cells is the indirect pathway of the dorsomedial striatum (DMSD2), which receives DAergic innervation from collaterals of VTADA[->]NAcLat cells, making this a closed-loop circuit. Cocaine likely facilitates reward and sensitization not directly through actions in the GPe, but rather in the upstream DMS, where the cocaine-induced elevation of DA triggers a depression in DMSD2 cell activity. This cocaine-induced elevation in DA levels can be blocked by inhibition of GPePV cells, closing the loop. Interestingly, the level of GPePV cell activity prior to cocaine administration is correlated with the extent of reward and sensitization that animals experience in response to future administration of cocaine, indicating that GPePV cell activity is a key predictor of future behavioral responses to cocaine. Single nucleus RNA-sequencing of GPe cells indicated that genes encoding voltage-gated potassium channels KCNQ3 and KCNQ5 that control intrinsic cellular excitability are downregulated in GPePV cells following a single cocaine exposure, contributing to the elevation in GPePV cell excitability. Acutely activating channels containing KCNQ3 and/or KCNQ5 using the small molecule carnosic acid, a key psychoactive component of Salvia rosmarinus (rosemary) extract, reduced GPePV cell excitability and also impaired cocaine reward, sensitization, and volitional cocaine intake, indicating its potential as a therapeutic to counteract psychostimulant use disorder. Our findings illuminate the molecular and circuit mechanisms by which the GPe orchestrates brain-wide changes in response to cocaine that are required for reward, sensitization, and self-administration behaviors.

neuroscience↗

bioRxiv2023

Circuit mechanism underlying fragmented sleep and memory deficits in 16p11.2 deletion mouse model of autism

Sleep disturbances are prevalent in children with autism spectrum disorder (ASD) and have a major impact on the quality of life. Strikingly, sleep problems are positively correlated with the severity of ASD symptoms, such as memory impairment. However, the neural mechanisms underlying sleep disturbances and cognitive deficits in ASD are largely unexplored. Here, we show that non-rapid eye movement sleep (NREMs) is highly fragmented in the 16p11.2 deletion mouse model of ASD. The degree of sleep fragmentation is reflected in an increased number of calcium transients in the activity of locus coeruleus noradrenergic (LC-NE) neurons during NREMs. Exposure to a novel environment further exacerbates sleep disturbances in 16p11.2 deletion mice by fragmenting NREMs and decreasing rapid eye movement sleep (REMs). In contrast, optogenetic inhibition of LC-NE neurons and pharmacological blockade of noradrenergic transmission using clonidine reverse sleep fragmentation. Furthermore, inhibiting LC-NE neurons restores memory. Rabies-mediated unbiased screening of presynaptic neurons reveals altered connectivity of LC-NE neurons with sleep- and memory regulatory brain regions in 16p11.2 deletion mice. Our findings demonstrate that heightened activity of LC-NE neurons and altered brain-wide connectivity underlies sleep fragmentation in 16p11.2 deletion mice and identify a crucial role of the LC-NE system in regulating sleep stability and memory in ASD.

neuroscience↗

bioRxiv2023

Tissue-Specific Dependence of Th1 Cells on the Amino Acid Transporter SLC38A1 in Inflammation

Amino acid (AA) uptake is essential for T cell metabolism and function, but how tissue sites and inflammation affect CD4+ T cell subset requirements for specific AA remains uncertain. Here we tested CD4+ T cell AA demands with in vitro and multiple in vivo CRISPR screens and identify subset- and tissue-specific dependencies on the AA transporter SLC38A1 (SNAT1). While dispensable for T cell persistence and expansion over time in vitro and in vivo lung inflammation, SLC38A1 was critical for Th1 but not Th17 cell-driven Experimental Autoimmune Encephalomyelitis (EAE) and contributed to Th1 cell-driven inflammatory bowel disease. SLC38A1 deficiency reduced mTORC1 signaling and glycolytic activity in Th1 cells, in part by reducing intracellular glutamine and disrupting hexosamine biosynthesis and redox regulation. Similarly, pharmacological inhibition of SLC38 transporters delayed EAE but did not affect lung inflammation. Subset- and tissue-specific dependencies of CD4+ T cells on AA transporters may guide selective immunotherapies. HIGHLIGHTSO_LIT cells dynamically regulate glutamine amino acid transporters when activated C_LIO_LISLC38A1 supports Th1 cell mTORC1 and proliferation by redox and hexosamine pathways C_LIO_LITargeting SLC38A1 does not affect lung inflammation but delays IBD and EAE C_LIO_LINutrient transporter needs of T cell subsets vary based on disease and tissue site C_LI

immunology↗

bioRxiv2023

Spatiotemporal Mapping of brain cilia length and orientation reveals region-specific Oscillation

In this study, we conducted high-throughput spatiotemporal analysis of primary cilia length and orientation across 22 mouse brain regions. We developed automated image analysis algorithms, which enabled us to examine over 10 million individual cilia, generating the largest spatiotemporal atlas of cilia. We found that cilia length and orientation display substantial variations across different brain regions and exhibit fluctuations over a 24-hour period, with region-specific peaks during light-dark phases. Our analysis revealed unique orientation patterns of cilia at 45{degrees} intervals, suggesting that cilia orientation within the brain is not random but follows specific patterns. Using BioCycle, we identified circadian rhythms of cilia length in five brain regions: nucleus accumbens core, somatosensory cortex, and three hypothalamic nuclei. Our findings present novel insights into the complex relationship between cilia dynamics, circadian rhythms, and brain function, highlighting cilia crucial role in the brains response to environmental changes and regulation of time-dependent physiological processes. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=138 SRC="FIGDIR/small/546950v3_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@153135corg.highwire.dtl.DTLVardef@11c1d7eorg.highwire.dtl.DTLVardef@d47014org.highwire.dtl.DTLVardef@10a65ca_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2022

Mapping long-term changes in inputs to the ventral tegmental area after a single drug exposure

Addictive drugs cause long-lasting changes in connectivity from inputs onto ventral tegmental area dopamine cells (VTADA) that contribute to drug-induced behavioral adaptations. However, it is not known which inputs are altered. Here we used a rabies virus (RABV)-based mapping strategy to quantify RABV-labeled inputs to VTA cells after a single exposure to one of a variety of misused drugs - cocaine, amphetamine, methamphetamine, morphine, and nicotine - and compared the relative global input labeling across conditions. We observed that all tested addictive drugs elicited similar input changes onto VTADA cells, in particular onto DA cells projecting to the lateral shell of the nucleus accumbens and amygdala. In addition, repeated administration of ketamine/xylazine to induce anesthesia induces a change in inputs to VTADA cells that is similar to but different from those elicited by a single exposure to addictive drugs, suggesting that caution should be taken when using ketamine/xylazine-based anesthesia in rodents when assessing motivated behaviors. Furthermore, comparison of viral tracing data to an atlas of gene expression in the adult mouse brain showed that the basal expression patterns of several gene classes, especially calcium channels, were highly correlated with the extent of both addictive drug- or ketamine/xylazine-induced changes in RABV-labeled inputs to VTADA cells. Reducing expression levels of the voltage-gated calcium channel Cacna1e in cells in the nucleus accumbens lateral shell reduced RABV-mediated input labeling of these cells into VTADA cells. These results directly link genes controlling cellular excitability and the extent of input labeling by RABV.

neuroscience↗

bioRxiv2022

Modified viral-genetic mapping reveals local and global connectivity relationships of ventral tegmental area dopamine cells

Dopamine cells in the ventral tegmental area (VTADA) are critical for a variety of motivated behaviors. These cells receive synaptic inputs from over 100 anatomically-defined brain regions, which enables control from a distributed set of inputs across the brain. Extensive efforts have been made to map inputs to VTA cells based on neurochemical phenotype and output site. However, all of these studies have the same fundamental limitation that inputs local to the VTA cannot be properly assessed due to non-Cre-dependent uptake of EnvA-pseudotyped virus. Therefore, the quantitative contribution of local inputs to the VTA, including GABAergic, DAergic, and serotonergic, is not known. Here, we used a modified viral-genetic strategy that enables examination of both local as well as long-range inputs to VTADA cells. We found that nearly half of the total inputs to VTADA cells are located locally, revealing a substantial portion of inputs that have been missed by previous analyses. The majority of inhibition to VTADA cells arises from the substantia nigra pars reticulata, with large contributions from the VTA and the substantia nigra pars compacta. In addition to receiving inputs from VTAGABA neurons, DA neurons are connected with other DA neurons within the VTA as well as the nearby retrorubal field. Lastly, we show that VTADA neurons receive inputs from distributed serotonergic neurons throughout the midbrain and hindbrain, with the majority arising from the dorsal raphe. Our study highlights the importance of using the appropriate combination of viral-genetic reagents to unmask the complexity of connectivity relationships to defined cells in the brain.

neuroscience↗

bioRxiv2021

An extended amygdala-midbrain circuit controlling cocaine withdrawal-induced anxiety and reinstatement

While midbrain dopamine (DA) neuronal circuits are central to motivated behaviors, much remains unknown about our knowledge of how these circuits are modified over time by experience to facilitate selective aspects of experience-dependent plasticity. Most studies of the DA system in drug addiction focus on the role of the mesolimbic DA pathway from the ventral tegmental area (VTA) to the nucleus accumbens (NAc) in facilitating drug-associated reward. In contrast, less is known about how midbrain DA cells and associated circuits contribute to negative affective states including anxiety that emerge during protracted withdrawal from drug administration. Here, we demonstrate the selective role of a midbrain DA projection to the amygdala (VTADA[->]Amygdala) for anxiety that develops during protracted withdrawal from cocaine administration but does not participate in cocaine reward or sensitization. Our rabies virus-mediated circuit mapping approach revealed a persistent elevation in spontaneous and task-related activity of GABAergic cells from the bed nucleus of the stria terminals (BNST) and downstream VTADA[->]Amygdala cells that could be detected even after a single cocaine exposure. Activity in BNSTGABA cells was related to cocaine-induced anxiety but not reward or sensitization, and silencing the projection from these cells to the midbrain was sufficient to prevent the development of anxiety during protracted withdrawal following cocaine administration. We observed that VTADA[->]Amygdala cells, but not other midbrain DA cells, were strongly activated after a challenge exposure to cocaine, and found that activity in these cells was necessary for the expression of reinstatement of cocaine place preference. Lastly, the importance of activity in VTADA[->]Amygdala cells extends beyond cocaine, as these cells mediate the development of anxiety states triggered by morphine and a predator odor. Our results provide an exemplar for how to identify key circuit substrates that contribute to behavioral adaptations and reveal a critical role for BNSTGABA[->]VTADA[->]Amygdala pathway in anxiety states induced by drugs of abuse or natural experiences as well as cocaine-primed reinstatement of conditioned place preference.

neuroscience↗

bioRxiv2021

The Relationship between Birth Timing, Circuit Wiring, and Physiological ResponseProperties of Cerebellar Granule Cells

Cerebellar granule cells (GrCs) are usually regarded as a uniform cell type that collectively expands the coding space of the cerebellum by integrating diverse combinations of mossy fiber inputs. Accordingly, stable molecularly or physiologically defined GrC subtypes within a single cerebellar region have not been reported. The only known cellular properties that distinguishes otherwise homogeneous GrCs is the correspondence between GrC birthtime and the depth of the molecular layer to which their axons (parallel fibers) project. To determine the role birth timing plays in GrC wiring and function, we developed genetic strategies to access early- and late-born GrCs. We initiated retrograde monosynaptic rabies virus tracing from control, early-born, and late-born GrCs, revealing the different patterns of mossy fiber input to GrCs in vermis lobule 6 and simplex, as well as to early- and late-born GrCs of vermis lobule 6: sensory and motor nuclei provide more input to early-born GrCs, while basal pontine and cerebellar nuclei provide more input to late-born GrCs. In vivo multi-depth 2-photon Ca2+ imaging of parallel fibers of early- and late-born GrCs revealed representations of diverse task variables and stimuli by both populations, with differences in the proportions of parallel fibers encoding movement, reward anticipation, and reward consumption. Our results suggest neither organized parallel processing nor completely random organization of mossy fiber[->]GrC circuitry, but instead a moderate influence of birth timing on GrC wiring and encoding. Our imaging data also suggest that GrCs can represent general aversiveness, in addition to recently described reward representations. Significance StatementCerebellar granule cells (GrCs) comprise the majority of all neurons in the mammalian brain and are usually regarded as a uniform cell type. However, the birth timing of an individual GrC dictates where its axon projects. Using viral-genetic techniques, we find that early- and late-born GrCs receive different proportions of inputs from the same set of input regions. Using in vivo multi-depth 2-photon Ca2+ imaging of axons of early- and late-born GrCs, we found that both populations represent diverse task variables and stimuli, with differences in the proportions of axons in encoding of a subset of movement and reward parameters. These results indicate that birth timing contributes to the input selection and physiological response properties of GrCs.

neuroscience↗