Biology subjects

Bellocchio, L.

Publications and source records attributed to Bellocchio, L..

13 recordsLinked to original sources

bioRxiv2026

Selective Shank3 Deletion in Glutamatergic Neurons of the Anterior Insular Cortex Induces Autism-Related Behavior and Circuit Dysfunction

Mutations in the synaptic scaffold protein SHANK3 represent one of the most frequent genetic causes of autism spectrum disorder (ASD), yet the circuit mechanisms through which SHANK3 dysfunction leads to behavioral alterations remain incompletely understood. The anterior insular cortex (aINS) is a key integrative hub involved in socio-emotional processing, anxiety regulation, and social cognition, a group of behaviors frequently disrupted in ASD. Here, we investigated whether selective deletion of SHANK3 signaling in glutamatergic neurons of the aINS is sufficient to produce ASD-relevant behavioral and circuit phenotypes. Using conditional Shank3flox4-22 mice combined with stereotaxic viral delivery of Cre recombinase under the CaMKII promoter, we selectively deleted Shank3 in glutamatergic neurons of the aINS. Behavioral phenotyping revealed increased anxiety-like behavior, enhanced repetitive behavior, and impaired social memory, while sociability and locomotor activity were largely preserved. These behavioral alterations were accompanied by genotype-dependent differences in neuronal activity revealed by calcium imaging, indicating disrupted activity dynamics in insular glutamatergic neurons following Shank3 deletion. To assess the broader relevance of these findings, we evaluated the behavioral profile of BTBR T+ Itpr3tf/J mice, a model of idiopathic ASD, in the same battery of behavioral tests. Several behavioral alterations observed following insular Shank3 deletion partially overlapped with those present in BTBR mice, supporting the relevance of aINS Shank3 in ASD-related phenotypes. Together, these findings identify glutamatergic neurons of the aINS as a critical locus through which Shank3 dysfunction can disrupt socio-emotional, cognitive, and repetitive behaviors. Our results highlight the aINS as a key circuit node contributing to ASD-related behavioral alterations and provide mechanistic insight into how synaptic scaffold disruption leads to circuit dysfunction and produces behavioral alterations.

neuroscience↗

bioRxiv2026

Ventromedial striatal GABAergic interneurons sex-dependently gate cost-benefit choices between food and exercise

Healthy energy balance relies on an equilibrated trade-off between the respective drives for food and exercise. However, the motivation circuitry underlying the choice between these two rewards remains unknown. Here, we developed a neuroeconomic model wherein mice living in operant chambers needed to choose between standard food and wheel running under increasing effort demands. Reward seeking resistance to increasing costs was then quantified using feeding and exercise essential values (EVs). Through conditional genetics and viral approaches, we show that cannabinoid type-1 receptors (CB1Rs) located on GABAergic neurons gate in necessary and sufficient manners exercise EV, exercise preference over feeding and exercise duration per rewarded sequence. Further, we report that these GABAergic neurons are located in the ventromedial striatum in males, but not females. CB1R deletion from medium spiny neurons did not impact exercise motivation, revealing an unforeseen role for ventromedial striatal GABAergic interneurons in effort-based decision-making between food and exercise.

neuroscience↗

bioRxiv2025

Obesogenic diet impairs memory consolidation via the hippocampal endocannabinoid system

Although obesogenic high-fat/high-sugar diets impair memory function in humans and rodents, the underlying mechanisms remain elusive. Given that the brain endocannabinoid system and type-1 cannabinoid receptors (CB1R) control memory processes and are overactive under obesogenic conditions, we studied whether the effects of obesogenic diet consumption on memory function are dependent on this system. Using an object recognition memory (ORM) task in male mice, we showed that CB1R activity is required for obesogenic diet-induced impairment of long-term memory performance. This impairment was prevented by post-training systemic blockade of CB1R, which also normalized training-induced hippocampal cellular and synaptic overactivation. Consistently, obesogenic diet potentiated the increase of hippocampal endocannabinoid levels and enhanced CB1R expression induced by ORM, and genetic CB1R deletion from hippocampal glutamatergic neurons abolished diet-induced memory deficits. Strikingly, obesogenic diet enhanced the hippocampal mTOR pathway in a CB1R-dependent manner, and pharmacological mTOR inhibition after training rescued diet-induced ORM consolidation deficits. Together, these results establish how an obesogenic environment can lead to hippocampal overactivation of the endocannabinoid system and of the mTOR pathway to eventually impair memory consolidation. Thus, these results shed light on the mechanisms of diet-induced cognitive alterations and may pave the way to novel therapeutic strategies. HighlightsO_LIObesogenic diet induces long-term memory deficits, which are rescued by CB1R blockade C_LIO_LICB1R blockade rescues diet-induced aberrant hippocampal activity/plasticity after training C_LIO_LIObesogenic diet enhances hippocampal endocannabinoid levels and CB1R after training C_LIO_LIDeletion of hippocampal CB1R rescues diet-induced long-term memory deficits C_LIO_LIObesogenic diet enhances hippocampal mTOR phosphorylation after training C_LIO_LImTOR inhibition rescues diet-induced memory consolidation deficits C_LI

neuroscience↗

bioRxiv2025

Pregnenolone and AEF0117 block cannabinoid-induced hyperlocomotion through GSK3β signaling at striatopallidal neurons

Administration of {Delta}9-tetrahydrocannabinol (THC), the main psychoactive component of the plant Cannabis sativa, can induce psychotic symptomatology in humans and a large spectrum of acute psychotic-like behaviors in mice, including hyperlocomotion observed at low dose of THC (0.3 mg/kg). The cellular and molecular substrates of this effect have not been fully identified yet. Here we demonstrate that THC-induced hyperlocomotion depends on plasma membrane CB1R, which regulate the {beta}-arrestin 1/Akt/GSK3{beta} signaling pathway in D2R-positive neurons of the dorsal striatum forming the striatopallidal pathway of the basal ganglia. Pregnenolone (PREG) and its clinically developed analog, AEF0117, which are signaling specific inhibitors of CB1R (CB1-SSi), prevented GSK3{beta}-dependent psychomotor stimulation induced by THC. Overall, this work highlights a novel intracellular mechanism of CB1R, thereby revealing a neuronal pathway underlying an important but still underexplored effect of THC and cannabis consumption, which could help the development of innovative therapeutic concepts against psychotic conditions.

neuroscience↗

bioRxiv2024

Unravelling the microplastic menace: different polymers work in synergy to increase bee vulnerability

Microplastics (MPs) are growing and ubiquitous environmental pollutants and represent one of the greatest contemporary challenges caused by human activities. Current research has predominantly examined the singular toxicological effects of individual polymers, neglecting the prevailing reality of organisms confronted with complex contaminant mixtures and potential synergistic effects. To fill this research gap, we investigated the lethal and sublethal effects of two common MPs, polystyrene (PS - 4.8-5.8 m) and poly(methyl methacrylate) (PMMA - 1-40 m), and their combination (MIX), on the pollinating insect Apis mellifera. For each treatment, we evaluated the oral toxicity of two ecologically relevant and one higher concentration (0.5, 5 and 50 mg/L) and analysed their effects on the immune system and worker survival. As immune activation can alter the cuticular hydrocarbon profile of honey bees, we used gas chromatography-mass spectrometry (GC-MS) to investigate whether MPs lead to changes in the chemical profile of foragers and behavioural assay to test whether such changes affect behavioural patterns of social recognition, undermining overall colony integrity. The results indicate a synergistic negative effect of PS and PMMA on bee survival and immune response, even at ecologically relevant concentrations. Furthermore, alterations in cuticle profiles were observed with both MPs at the highest and intermediate concentrations, with PMMA being mainly responsible. Both MPs exposure resulted in a reduction in the abundance of several cuticular compounds. Hive entry guards did not show increased inspection or aggressive behaviour towards exposed foragers, allowing them to enter the colony without being treated differently from uncontaminated foragers. These findings raise concerns not only for the health of individual bees, but also for the entire colony, which could be at risk if contaminated nestmates enter the colony undetected, allowing MPs to spread throughout the hive.

animal behavior and cognition↗

bioRxiv2024

Cannabinoid type-1 (CB1) receptors in glial cells promote neuromuscular junction repair following nerve injury.

Cannabinoids are frequently used in the treatment of neuropathic pain related to nerve injury. However, despite evidence for their roles in the regulation of axonal guidance and synapse formation during development of the central nervous system (CNS), their possible involvement in response to peripheral nerve injury remains poorly defined and the knowledge of its role is mostly related to the peripheral sensory system. Following nerve injury, contemporary to axonal repair, massive morphological and functional changes reshape synaptic elements at neuromuscular junctions (NMJs) aiming to promote their reinnervation. This process is mediated in part by Perisynaptic Schwann cells (PSCs), glial cells at the NMJ essential for its maintenance and repair. Here we investigated the novel role of Cannabinoid type-1 receptor (CB1R) at NMJ, in particular on PSCs, during motor nerve recovery following nerve injury. Using morphological analysis, we studied the consequences of CB1R pharmacological and genetic blockade following denervation and reinnervation in adult NMJs. CB1R blockade caused an acceleration of the denervation process followed by a great delay in reinnervation as indicated by a significant percentage of denervated NMJs, accompanied by a decrease of mono- and poly-innervated NMJs. Remarkably, a similar phenomenon was observed when CB1R is selectively knocked-out in glia, indicating that the protective actions of these receptors are largely glia-dependent. These data highlight a novel role of the endocannabinoid system at NMJs, where the CB1Rs on PSCs can control NMJ denervation and reinnervation following nerve injury. A better understanding of the functional mechanisms underlying CB1R role in NMJ repair may contribute to finding a new pharmacological treatment having a dual role in improvements of motor recovery and in pain-related relief.

neuroscience↗

bioRxiv2023

The CB1 receptor interacts with cereblon and drives cereblon deficiency-associated memory shortfalls

Cereblon/CRBN is a substrate-recognition component of the Cullin4A-DDB1-Roc1 E3 ubiquitin ligase complex. Destabilizing mutations in the human CRBN gene cause a form of autosomal recessive non-syndromic intellectual disability (ARNSID) that is modelled by knocking-out the mouse Crbn gene. A reduction in excitatory neurotransmission has been proposed as an underlying mechanism of the disease, but the intimate factors eliciting this impairment remain mostly unknown. Here we report that CRBN molecules selectively located on glutamatergic neurons are necessary for proper memory function. Combining various in vivo approaches, we show that the cannabinoid CB1 receptor (CB1R), a key suppressor of synaptic transmission, is overactivated in CRBN deficiency-linked ARNSID mouse models, and that the memory deficits observed in these animals can be rescued by acute CB1R-selective pharmacological antagonism. Molecular studies demonstrated that CRBN interacts physically with CB1R and impairs the CB1R-Gi/o-cAMP-PKA pathway in a ubiquitin ligase-independent manner. Taken together, these findings unveil that CB1R overactivation is a driving mechanism of CRBN deficiency-linked ARNSID and anticipate that the blockade of CB1R could constitute a new therapy for this orphan disease.

neuroscience↗

bioRxiv2023

A lactate-dependent shift of glycolysis mediates synaptic and cognitive processes

Control of brain energy metabolism and regulation of synaptic activity through gliotransmission are two important ways, through which astrocytes contribute to mental functions. However, the potential functional and molecular links between these two astrocyte-dependent processes have been scantly explored. Here we show that a lactate-dependent shift of glycolysis underlies the production of the gliotransmitter D-serine by acute activation of astrocyte type-1 cannabinoid (CB1) receptors, thereby gating synaptic and cognitive processes. Acute cannabinoid application causes a CB1 receptor-dependent rapid and reversible increase of lactate production and release in primary astrocyte cultures. As shown before, mutant mice lacking the CB1 receptor gene in astrocytes (GFAP-CB1-KO) were impaired in a novel object recognition (NOR) memory task. This phenotype was rescued not only by the gliotransmitter D-serine, but also by its precursor L-serine. Surprisingly, the administration of lactate and of an agonist of the lactate receptor HCAR1 also reverted the memory impairment of GFAP-CB1-KO mice. This rescue effect was abolished by in vivo blockade of the astrocyte-specific phosphorylated pathway (PP), which diverts glycolysis towards L-serine synthesis, suggesting that lactate signaling might promote the accumulation of this amino acid. Consistent with this idea, lactate and HCAR1 agonism increased the co-agonist occupancy of CA1 post-synaptic hippocampal NMDA receptors. This effect of lactate was abolished by blockade of PP. By establishing a mechanistic link between lactate production and signaling, serine availability, synaptic activity and behavior, these results reveal an unforeseen functional connection between energy metabolism and gliotransmission to control cognitive processes.

neuroscience↗

bioRxiv2022

Cannabinoids regulate an insula circuit controlling water intake

The insular cortex, or insula, is a large brain region involved in the detection of thirst and the control of water intake. However our understanding of the topographical, circuit and molecular mechanisms the controlling water intake within the insula remains parcellated. We found that type-1 cannabinoid receptors (CB1) within the insular cortex participate to the regulation of water intake, and deconstructed circuit mechanisms of this control. Topographically, we revealed that the activity of excitatory neurons in both anterior (aIC) and posterior (pIC) insula increases in response to water intake, yet removal of CB1 receptors only in the pIC decreases water intake. Interestingly, we found that CB1 receptors are highly expressed in insula projections to the basolateral amygdala (BLA), while undetectable in the neighboring central part of the amygdala. Thus, we imaged the neurons of the anterior or posterior insula targeting the BLA (aIC-BLA and pIC-BLA), and found they oppositely respond to water intake, respectively decreasing and increasing their activity upon water drinking. Consistently, chemogenetic activation of pIC-BLA neurons decreased water intake. Finally, we uncovered CB1-dependent short term synaptic plasticity (depolarization-induced suppression of excitation, DSE) selectively in pIC-BLA, compared to aIC-BLA synapses. Altogether, our results support a model where CB1 signaling in the pIC-BLA pathway exerts a positive control on water intake.

neuroscience↗

bioRxiv2020

A new mutant mouse model lacking mitochondrial-associated CB1 receptor

The idea that the effects of drugs largely depend on subcellular target location is emerging as a novel predictive factor of their beneficial or adverse outcomes. G protein-coupled type-1 cannabinoid receptors (CB1) are regulators of several brain functions as well as the main targets of cannabinoid-based medicines. Besides their classical location at plasma membranes, CB1 receptors are present at different locations within cells, including in association to mitochondrial membranes (mtCB1). Here we report the generation and characterization of a mutant mouse line, which lack mtCB1 receptors.

neuroscience↗

bioRxiv2020

POMC neurons functional heterogeneity relies on mTORC1 signaling

Hypothalamic Pro-opiomelanocortin (POMC) neurons are classically known to trigger satiety. However, they encompass heterogeneous subpopulations whose functions are unknown. Here we show that POMC neurons releasing GABA, glutamate or both neurotransmitters possess distinct spatial distribution, molecular signatures and functions. Functional specificity of these subpopulations relies on the energy sensor mechanistic Target of Rapamycin Complex 1 (mTORC1), since pharmacological blockade of mTORC1, by mimicking a cellular negative energy state, simultaneously inhibited POMC/glutamatergic and activated POMC/GABAergic neurons. Chemogenetics and conditional deletion of mTORC1 then demonstrated that mTORC1 blockade in POMC neurons causes hyperphagia. This is due to decreased POMC-derived anorexigenic -melanocyte-stimulating hormone and the recruitment of POMC/GABAergic neurotransmission, which is restrained by cannabinoid type 1 receptor signaling. Genetic inhibition of glutamate release from POMC neurons also produced hyperphagia, recapitulating the phenotype caused by mTORC1 blockade. Altogether, these findings pinpoint the molecular mechanisms engaged by POMC neurons to oppositely control feeding, thereby challenging conventional views about their functions.

neuroscience↗

bioRxiv2019

Specific hippocampal interneurons shape consolidation of recognition memory

A complex array of different inhibitory interneurons tightly controls hippocampal activity, but how such diversity specifically impacts on memory processes is scantly known. We found that a small subclass of type-1 cannabinoid receptor (CB1)-expressing hippocampal interneurons determines episodic-like memory consolidation by linking dopamine D1 receptor signaling to GABAergic transmission. Mice lacking CB1 in D1-positive cells (D1-CB1-KO) displayed impaired long-term, but not short-term, object recognition memory. Re-expression of CB1 in hippocampal, but not striatal, D1-positive cells rescued this memory impairment. Learning induced a facilitation of in vivo hippocampal long-term potentiation (LTP), which was abolished in mutant mice. Chemogenetic and pharmacological experiments revealed that both CB1-mediated memory and associated LTP facilitation involves the local control of GABAergic inhibition in a D1-dependent manner. This study reveals that CB1-/D1-expressing interneurons shape hippocampal circuits to sustain recognition memory, thereby identifying a mechanism linking the diversity of hippocampal interneurons to specific behavioral and cognitive outcomes.

neuroscience↗

bioRxiv2019

Top-down control of water intake by the endocannabinoid system

Water intake is regulated by neocortical top-down circuits, but their identity and the cellular mechanisms involved are scantly known. Here, we show that endogenous activation of type-1 cannabinoid receptors (CB1) promotes water intake and that endocannabinoid modulation of excitatory projections from the anterior cingulate cortex to the basolateral amygdala is sufficient to guarantee physiological drinking. These data reveal a new circuit involved in the homeostatic control of water intake.

neuroscience↗