Biology subjects

Bortolato, M.

Publications and source records attributed to Bortolato, M..

11 recordsLinked to original sources

bioRxiv2026

Sleep deprivation impairs information processing via dysregulation of chloride homeostasis in the prefrontal cortex

Sleep deprivation (SD) impairs information processing through alterations of prefrontal cortex (PFC) function, yet the molecular underpinnings of this process remain poorly understood. We previously showed that SD disrupts sensorimotor gating by elevating prefrontal levels of the neurosteroid allopregnanolone (AP), a positive allosteric modulator of GABA-A receptors. Here we identify a complementary, mechanistically independent process whereby SD alters GABA-A currents in the PFC of mice and rats. SD reduced membrane expression of the chloride exporter KCC2, leading to intracellular chloride accumulation and a depolarizing shift in GABA-A receptor reversal potential that weakened GABAergic inhibition. Pharmacological normalization of chloride homeostasis with bumetanide fully rescued SD-induced deficits in sensorimotor gating and information encoding. SD also upregulated BDNF, and intra-PFC antagonism of its receptor TrkB restored KCC2 expression and normalized information processing, identifying BDNF-TrkB signaling as an upstream driver of chloride dysregulation. Notably, blocking AP synthesis rescued behavioral deficits without correcting chloride imbalance, confirming mechanistic independence. Finally, combined administration of AP and a KCC2 blocker produced information-processing deficits akin to those induced by SD. These findings identify TrkB-dependent disruption of prefrontal chloride homeostasis as a druggable mechanism underlying sleep loss-induced cognitive dysfunction.

animal behavior and cognition↗

bioRxiv2026

Single-nucleus transcriptomics reveal stress-related prefrontal activation in Tourette disorder

Tourette disorder (TD) is a neurodevelopmental condition with a robust genetic basis, characterized by multiple motor and vocal tics. Tics arise from dysfunction within cortico-striatal-thalamo-cortical circuits, with pathological evidence largely implicating striatal interneuron deficits and microglial activation. Recently, the largest genome-wide association study (GWAS) meta-analysis of TD identified polygenic risk enrichment in Brodmann area 9 (BA9), corresponding to the dorsolateral prefrontal cortex (DLPFC), a region implicated in executive control and tic suppression. However, the molecular landscape of BA9 in TD remains unexplored. Here, we performed single-nucleus RNA sequencing of postmortem BA9 from five males with TD and five matched controls, yielding 72,340 nuclei across neuronal and glial populations. While cell-type proportions were preserved, transcriptional remodeling was pervasive. In particular, biosynthetic and translational programs were upregulated across microglia, interneurons, oligodendrocytes, and superficial- and middle-layer excitatory neurons. Most cell types showed enrichment for glucocorticoid-responsive and immediate early gene modules consistent with stress-associated transcriptional activation. Finally, cross-regional comparison with striatal datasets revealed conservation of microglial and oligodendrocyte programs. These findings point to extensive transcriptional reprogramming in the DLPFC of individuals with TD, characterized by stress-associated activation, most strongly in oligodendrocytes and neurons.

neuroscience↗

bioRxiv2025

Prefrontal 5-HT2A receptors directly contribute to tic ontogeny: translational evidence

Tourette syndrome (TS) is a neuropsychiatric disorder characterized by motor and vocal tics and frequently accompanied by comorbidities such as obsessive-compulsive disorder (OCD) and pathological aggression. Although approved pharmacotherapies often reduce tic severity, they frequently cause adverse effects and are insufficient for managing comorbid symptoms, underscoring the need for improved treatments. Recent evidence indicates that the serotonin 5-HT2A receptor (5-HT2AR) antagonist pimavanserin reduces tic severity and improves quality of life, yet its mechanism of action in TS remains unclear. Here, we combine postmortem human and preclinical approaches to gain insight into the role of 5-HT2ARs in TS. Western-blot analyses of postmortem prefrontal cortex (PFC) samples obtained from individuals with TS revealed a pronounced, male-specific elevation of 5-HT2AR protein levels in Brodmann Area (BA) 10. We then tested pimavanserin and the selective 5-HT2AR antagonist volinanserin in two mouse models of TS: D1CT-7 transgenic mice and mice with early-life depletion of striatal cholinergic interneurons. Systemic administration of pimavanserin (1-2 mg{middle dot}kg-{superscript 1}, IP) or volinanserin (0.1-0.3 mg{middle dot}kg-{superscript 1}, IP) robustly reduced tic-like movements and stereotypies in both models. Local infusion of pimavanserin into the medial PFC, but not the dorsal striatum, recapitulated these effects, indicating a cortical locus of action. Pimavanserin also reduced resident-intruder aggression, but not locomotion or anxiety-like behavior. Together, these findings identify elevated prefrontal 5-HT2ARs as a key mechanistic contributor to TS and a promising therapeutic target for individuals with TS and pathological aggression.

neuroscience↗

bioRxiv2024

Prefrontal 5α-reductase 2 mediates male-specific acute stress response

A key response to acute stress is the increased brain synthesis of the neurosteroid allopregnanolone (AP). While the rate-limiting step of this reaction is catalyzed by 5-reductase (5R), the role of its two primary isoenzymes, 5R1 and 5R2, in stress reactivity remains unclear. Here, we found that acute stress led to increased levels of 5R2, but not 5R1, in the medial prefrontal cortex (mPFC) of male, but not female, rats. Downregulation of 5R2 in the mPFC significantly reduced stress response in males, and similar sexual dimorphic effects were observed in a novel line of 5R2 knockout rats. Notably, 5R1 regulated baseline AP synthesis, while 5R2 enabled AP production under stress. Acute AP administration restored stress response in 5R2 knockdown rats. Single-nucleus transcriptomics showed that 5R2 enabled stress-induced protein translation in neurons and glia. These results highlight the crucial role of 5R2 in mediating sex-specific differences in acute stress reactivity.

neuroscience↗

bioRxiv2023

CELSR3 deficiency leads to tic-related behaviors and dopaminergic alterations in the striatum

The gene CELSR3 (Cadherin EGF LAG Seven-pass-G-type Receptor 3) has been recently recognized as a high-confidence risk factor for Tourette syndrome (TS). Additionally, Celsr3 mutant mice have been reported to exhibit TS-related behaviors and increased dopamine release in the striatum. Building on these findings, we further characterized the neurobehavioral and molecular profile of Celsr3 mutant mice to understand better the biological mechanisms connecting the deficiency of this gene and TS-related phenotypes. Our analyses confirmed that Celsr3 mutant mice displayed grooming stereotypies and tic-like jerks, as well as sensorimotor gating deficits, which were opposed by TS therapies. Spatial transcriptomic analyses revealed widespread extracellular matrix abnormalities in the striatum of Celsr3 mutants. Single-nucleus transcriptomics also showed significant upregulation of the Drd3 gene, encoding the dopamine D3 receptor, in striosomal D1-positive neurons. In situ hybridization and immunofluorescence confirmed dysregulated D3 receptor expression, with lower levels in presynaptic striatal fibers and higher levels in striatal D1-positive neurons. Activating and blocking D3 receptors amplified or decreased tic-like jerks and stereotypies in Celsr3-deficient mice, respectively. These findings suggest that modifications of D3 receptor distribution contribute to the tic-like responses associated with Celsr3 deficiency.

neuroscience↗

bioRxiv2023

A novel naive Bayes approach to identifying grooming behaviors in the force-plate actometric platform

BackgroundSelf-grooming behavior in rodents serves as a valuable model for investigating stereotyped and perseverative responses. Most current grooming analyses primarily rely on video observation, which lacks standardization, efficiency, and quantitative information about force. To address these limitations, we developed an automated paradigm to analyze grooming using a force-plate actometer. New MethodGrooming behavior is quantified by calculating ratios of relevant movement power spectral bands. These ratios are then input into a naive Bayes classifier, trained with manual video observations. To validate the effectiveness of this method, we applied it to the behavioral analysis of the early-life striatal cholinergic interneuron depletion (CIN-d) mouse, a model of tic pathophysiology recently developed in our laboratory, which exhibits prolonged grooming responses to acute stressors. Behavioral monitoring was simultaneously conducted on the force-place actometer and by video recording. ResultsThe naive Bayes approach achieved 93.7% accurate classification and an area under the receiver operating characteristic curve of 0.894. We confirmed that male CIN-d mice displayed significantly longer grooming durations compared to controls. However, this elevation was not correlated with increases in grooming force. Notably, haloperidol, a benchmark therapy for tic disorders, reduced both grooming force and duration. Comparison with Existing MethodsIn contrast to observation-based approaches, our method affords rapid, unbiased, and automated assessment of grooming duration, frequency, and force. ConclusionsOur novel approach enables fast and accurate automated detection of grooming behaviors. This method holds promise for high-throughput assessments of grooming stereotypies in animal models of tic disorders and other psychiatric conditions.

neuroscience↗

bioRxiv2022

Prefrontal allopregnanolone mediates the adverse effects of acute stress in a mouse model of tic pathophysiology

Ample evidence suggests that acute stress can worsen symptom severity in Tourette syndrome (TS); however, the neurobiological underpinnings of this phenomenon remain poorly understood. We previously showed that acute stress exacerbates tic-like and other TS-associated responses via the neurosteroid allopregnanolone (AP) in an animal model of repetitive behavioral pathology. To verify the relevance of this mechanism to tic pathophysiology, here we tested the effects of AP in a mouse model recapitulating the partial depletion of cholinergic interneurons (CINs) in the striatum seen in postmortem studies of TS. Mice underwent targeted depletion of striatal CINs during adolescence and were tested in young adulthood. Compared with controls, CIN-depleted male mice exhibited several TS-relevant abnormalities, including deficient prepulse inhibition (PPI) and increased grooming stereotypies after a 30-min session of spatial confinement, a mild acute stressor that increases AP synthesis in the prefrontal cortex (PFC). These effects were not seen in females. Systemic and intra-PFC AP administration dose-dependently worsened grooming stereotypies and PPI deficits in CIN-depleted males. Conversely, both AP synthesis inhibition and pharmacological antagonism reduced the effects of stress. These results further suggest that AP in the PFC mediates the adverse effects of stress on the severity of tics and other TS manifestations. Future studies will be necessary to confirm these mechanisms in patients and define the circuitry responsible for the effects of AP on tics.

animal behavior and cognition↗

bioRxiv2022

Endocannabinoid-dependent persistent decrease of GABAergic transmission on dopaminergic neurons underlies gene-environment interaction-induced susceptibility to cocaine sensitization

Vulnerability to develop cocaine use disorder depends upon an unpredictable combination of genetic and non-genetic risk factors. Early life adversity and adolescence are critical non-genetic risk factors, and haplotypes of the monoamine oxidase (MAO) genes are among genetic variations increasing the risk of drug-related problems. However, data on the interactions between inheritable risk factors and early life stress (ES) with respect to predisposition to cocaine abuse are limited. Here, we show that a mouse model containing both genetic (low-activity alleles of the MAO A gene; MAOANeo) and environmental (i.e., ES) variables displays a long lasting increased sensitivity to repeated in vivo cocaine psychomotor stimulant actions associated with a reduction of GABAA receptor-mediated inhibition of dopamine neurons of the ventral tegmental area (VTA). Depolarization-induced suppression of inhibition (DSI), a 2-arachidonoylglycerol (2-AG)-dependent form of short-term plasticity, also becomes readily expressed by dopamine neurons from MAOANeoES mice treated repeatedly with cocaine. Activation of either dopamine D2 or CB1 receptors is required for cocaine-induced DSI expression, decreased GABA synaptic efficacy, and hyperlocomotion. Next, in vivo pharmacological enhancement of 2-AG signaling during repeated cocaine exposure occludes its actions both in vivo and ex vivo. This data extends our knowledge of the multifaceted sequelae imposed by this gene by environment interaction in VTA dopamine neurons of male pre-adolescent mice, contributing to our understanding of neural mechanisms of vulnerability for early onset cocaine use disorder.

neuroscience↗

bioRxiv2022

Acute stress impairs sensorimotor gating via the neurosteroid allopregnanolone in the prefrontal cortex

Background and purposeAmple evidence indicates that environmental stress impairs information processing, yet the underlying mechanisms remain partially elusive. We showed that, in several rodent models of psychopathology, the neurosteroid allopregnanolone (AP) reduces the prepulse inhibition (PPI) of the startle, a well-validated index of sensorimotor gating. Since this GABAA receptor activator is synthesized in response to acute stress, we hypothesized its participation in stress-induced PPI deficits. Experimental approachWe studied whether and how AP influences PPI in mice and rats; thereafter, we tested APs implication in the PPI deficits produced by several complementary regimens of acute and short-term stress (footshock, restraint, predator exposure, and sleep deprivation). Key resultsSystemic AP administration reduced PPI in C57BL/6J mice and Long-Evans, but not Sprague-Dawley, rats. These effects were reversed by isoallopregnanolone (isoAP), an endogenous AP antagonist, and the GABAA receptor antagonist bicuculline and mimicked by AP infusions in the medial prefrontal cortex (mPFC). PPI was reduced by acute footshock, sleep deprivation as well as the combination of restraint and predator exposure in a time- and intensity-dependent fashion. Acute stress increased AP concentrations in the mPFC, and its detrimental effects on PPI were countered by systemic and intra-mPFC administration of isoAP. Conclusions and implicationsThese results collectively indicate that acute stress impairs PPI by increasing AP content in the mPFC. The confirmation of these mechanisms across distinct animal models and several acute stressors strongly supports the translational value of these findings and warrants future research on the role of AP in information processing.

neuroscience↗

bioRxiv2021

Top2a promotes the development of social behavior via PRC2 and H3K27me3

Human infants exhibit innate social behaviors at birth, yet little is understood about the embryonic development of sociality. We screened 1120 known drugs and found that embryonic inhibition of topoisomerase II (Top2a) resulted in lasting social deficits in zebrafish. In mice, prenatal Top2 inhibition caused behavioral defects related to core symptoms of autism, including impairments in social interaction and communication. Mutation of Top2a in zebrafish caused downregulation of a set of genes highly enriched for genes associated with autism in humans. Both the Top2a-regulated and autism-associated gene sets possess binding sites for polycomb repressive complex 2 (PRC2), a regulatory complex responsible for H3K27 trimethylation. Moreover, both gene sets are highly enriched for H3K27me3. Inhibition of PRC2 component Ezh2 rescued social deficits caused by Top2 inhibition. Therefore, Top2a is a key component of an evolutionarily conserved pathway that promotes the development of social behavior through PRC2 and H3K27me3.

animal behavior and cognition↗

bioRxiv2020

The 5α-reductase inhibitor finasteride reduces opioid self-administration

Opioid use disorder (OUD) has become a leading cause of death in the US, yet current therapeutic strategies remain highly inadequate. To identify novel potential treatments for OUD, we screened a targeted selection of over 100 drugs, using a recently developed opioid self-administration assay in zebrafish. This paradigm showed that finasteride, a steroidogenesis inhibitor approved for the treatment of benign prostatic hyperplasia and androgenetic alopecia, reduced self-administration of multiple opioids without affecting locomotion or feeding behavior. These findings were confirmed in rats; furthermore, finasteride did not interfere with the antinociceptive effect of opioids in rat models of neuropathic pain. Steroidomic analyses of the brains of fish treated with finasteride revealed a significant increase in dehydroepiandrosterone sulfate (DHEAS). Treatment with precursors of DHEAS reduced opioid self-administration in zebrafish, in a fashion akin to the effects of finasteride. Our results highlight the importance of steroidogenic pathways as a rich source of therapeutic targets for OUD and point to the potential of finasteride as a new option for this disorder.

neuroscience↗