Cannabinoid-induced motor dysfunction via autophagy inhibition

The recreational and medical use of cannabis is largely increasing worldwide. Cannabis use, however, can cause adverse side effects, so conducting innovative studies aimed to understand and potentially reduce cannabis-evoked harms is important. Previous research conducted on cultured neural cells had supported that CNR1/CB1R (cannabinoid receptor 1), the main molecular target of cannabis, affects macroautophagy/autophagy. However, it was not known whether CNR1 controls autophagy in the brain in vivo, and, eventually, what the functional consequences of a potential CNR1-autophagy connection could be. We have now found that Δ9-tetrahydrocannabinol (THC), the major intoxicating constituent of cannabis, impairs autophagy in the mouse striatum. Administration of autophagy activators (specifically, the rapalog temsirolimus and the disaccharide trehalose) rescues THC-induced autophagy inhibition and motor dyscoordination. The combination of various genetic strategies in vivo supports the idea that CNR1 molecules located on neurons belonging to the direct (striatonigral) pathway are required for the autophagy- and motor-impairing activity of THC. By identifying autophagy as a mechanistic link between THC and motor performance, our findings may open a new conceptual view on how cannabis acts in the brain

Subcellular specificity of cannabinoid effects in striatonigral circuits

Recent advances in neuroscience have positioned brain circuits as key units in controlling behavior, implying that their positive or negative modulation necessarily leads to specific behavioral outcomes. However, emerging evidence suggests that the activation or inhibition of specific brain circuits can actually produce multimodal behavioral outcomes. This study shows that activation of a receptor at different subcellular locations in the same neuronal circuit can determine distinct behaviors. Pharmacological activation of type 1 cannabinoid (CB1) receptors in the striatonigral circuit elicits both antinociception and catalepsy in mice. The decrease in nociception depends on the activation of plasma membrane-residing CB1 receptors (pmCB1), leading to the inhibition of cytosolic PKA activity and substance P release. By contrast, mitochondrial-associated CB1 receptors (mtCB1) located at the same terminals mediate cannabinoid-induced catalepsy through the decrease in intra-mitochondrial PKA-dependent cellular respiration and synaptic transmission. Thus, subcellular-specific CB1 receptor signaling within striatonigral circuits determines multimodal control of behavior

Rôle du récepteur cannabinoïde de type-1 dans la physiologie des ganglions de la base

Le système endocannabinoïde (ECS) est un réseau de neuromodulation impliqué dans un large éventail de fonctions physiologiques. Il est composé d’endocannabinoïdes, les récepteurs et les enzymes impliquées dans leurs biosynthèses et dégradations. Dans le système nerveux central l’action des endocannabinoïdes est principalement régulée par le récepteur cannabinoïde de type 1 (CB1), un GPCR à sept domaines transmembranaires exprimé de manière quasi ubiquitaire, situé dans plusieurs types de cellules mais aussi dans différents compartiments subcellulaires, à savoir les mitochondries. Les récepteurs CB1 sont également la cible principale des phytocannabinoïdes tels que le Δ-9-tétrahydrocannabinol (THC), le principal composé psycho-actif de la plante Cannabis Sativa. Lors d'une activation physiologique ou pharmacologique, les récepteurs CB1 modulent l'excitabilité neuronale et la libération de neurotransmetteurs, jouant ainsi un rôle crucial dans la transmission synaptique et la plasticité. L’un des pools les plus importants de récepteurs CB1 dans le cerveau est situé dans le striatum, la structure principale des ganglions de la base (BG). Les BG sont un groupe de noyaux sous-corticaux impliqués dans les boucles cortico-thalamique-corticales nécessaires aux comportements adaptatifs tels que la coordination motrice, l’apprentissage des habiletés motrices et la formation des mémoires procédurales. Le striatum, principalement composé de neurones épineux moyens (MSNs) GABAergiques, intègre les entrées glutamatergiques provenant des zones corticales et des noyaux thalamiques et module leur activité via ses structures cibles. Les MSNs sont divisés en deux populations neuronales formant les circuits direct et indirect, qui diffèrent pour leur région cible, respectivement Substantia Nigra pars reticulata (SNr) et Globus Pallidus externe (GPe). L’activation de ces deux voies induit une régulation opposée des noyaux thalamiques, cible finale des circuits des BG, et leur équilibre est considéré comme le mécanisme qui permet un large éventail de fonctions des BG. Les fibres dopaminergiques, qui proviennent de la Substantia Nigra pars compacta (SNc) sont un modulateur clé des circuits striataux. Le projet présenté dans ma thèse de doctorat visait à comprendre le rôle des récepteurs CB1 situés dans les différentes voies striatales. En particulier, en utilisant des manipulations virales et/ou génétiques pour cibler les récepteurs CB1 striataux, nous avons étudié leur implication dans l’action du THC ou de l’amphétamine, qui sont connus pour agir sur la physiologie striatale. De manière intéressante, nous avons trouvé une implication spécifique des récepteurs CB1 situés dans la voie directe ou indirecte dans la médiation des effets comportementaux et synaptiques de ces drogues. De plus, nous avons constaté qu’au sein d’un même circuit cérébral, différents pools subcellulaires de récepteurs CB1 sont impliqués dans différentes fonctions neurophysiologiques (libération de neurotransmetteur ou neuropeptides), et que leur activation entraîne donc des effets synaptiques et comportementaux différents. Nos résultats mettent en évidence des nouveaux rôles spécifiques des récepteurs CB1 en fonction de leur localisation, du circuit et/ou des compartiments subcellulaires, dans la médiation de l’action des drogues d’abus, représentant une nouvelle cible pour des traitements spécifiquesThe endocannabinoid system (ECS) is a neuromodulatoy network involved in a wide range of physiological functions. ECS comprises endocannabinoids, receptors, and enzymes involved in their synthesis and degradation. In the CNS the action of endocannabinoids is mainly mediated by the cannabinoid type-1 (CB1) receptor, a seven-transmembrane GPCR expressed almost ubiquitously, located in several cell types but also in subcellular compartments, i.e. mitochondria and plasma membranes. CB1 receptors are also the main target of phytocannabinoids such as Δ-9-tetrahydrocannabinol (THC), the main psycho-active compound of the plant Cannabis Sativa. Upon physiological or pharmacological activation, CB1 receptors can modulate neuronal excitability and neurotransmitter release, playing a crucial role in the regulation of synaptic transmission and plasticity. One of the highest pools of CB1 receptors in the brain is located in the striatum, the main structure of Basal Ganglia (BG). BG are a group of subcortical nuclei involved in cortico-thalamic-cortical loops necessary for adaptive behaviors such as motor coordination, motor skills learning, and procedural memory formations. The striatum, mainly composed by GABAergic medium spiny projection neurons (MSNs), represents the input structure of BG receiving glutamatergic inputs rising from cortical areas and thalamic nuclei. MSNs are segregated into two neuronal subpopulations forming the direct and indirect pathways, which project to the Substantia Nigra pars reticulata (SNr) or the external segment of the Globus Pallidus (GPe) respectively. The activation of these two pathways induces opposite regulation of thalamic nuclei, the final target of BG circuits, and their balance is thought to be the mechanism underlying the wide range of BG functions. Key modulators of BG circuits are dopaminergic fibers which originate from Substantia Nigra pars compacta (SNc) and exert opposite effects on MSNs belonging to direct or indirect pathway. However, the involvement of the ECS in the modulation of striatal activity and functions is poorly investigated. The project presented in my PhD thesis aimed at understand the distinct role of CB1 receptors in direct or indirect striatal MSNs. In particular, using viral and/or genetic manipulations to specifically target striatal CB1 receptors, we investigated the involvement of these receptors in mediating the action of THC or amphetamine, which are known to act on striatal physiology. Interestingly, we found a specific involvement of CB1 receptors located in direct vs indirect striatal pathways in mediating the behavioral effects of these drugs. Within the same brain circuit different subcellular pools of CB1 receptors are involved in different neurophysiological functions (neurotransmitter vs neuropeptide release), and therefore their activation mediates different synaptic and behavioral effects. Our results highlight new specific roles for CB1 receptors depending on their location, circuit and/or subcellular compartments, in mediating the action of drugs of abuse, representing a new target for specific treatment

Rôle du récepteur cannabinoïde de type-1 dans la physiologie des ganglions de la base

The endocannabinoid system (ECS) is a neuromodulatoy network involved in a wide range of physiological functions. ECS comprises endocannabinoids, receptors, and enzymes involved in their synthesis and degradation. In the CNS the action of endocannabinoids is mainly mediated by the cannabinoid type-1 (CB1) receptor, a seven-transmembrane GPCR expressed almost ubiquitously, located in several cell types but also in subcellular compartments, i.e. mitochondria and plasma membranes. CB1 receptors are also the main target of phytocannabinoids such as Δ-9-tetrahydrocannabinol (THC), the main psycho-active compound of the plant Cannabis Sativa. Upon physiological or pharmacological activation, CB1 receptors can modulate neuronal excitability and neurotransmitter release, playing a crucial role in the regulation of synaptic transmission and plasticity. One of the highest pools of CB1 receptors in the brain is located in the striatum, the main structure of Basal Ganglia (BG). BG are a group of subcortical nuclei involved in cortico-thalamic-cortical loops necessary for adaptive behaviors such as motor coordination, motor skills learning, and procedural memory formations. The striatum, mainly composed by GABAergic medium spiny projection neurons (MSNs), represents the input structure of BG receiving glutamatergic inputs rising from cortical areas and thalamic nuclei. MSNs are segregated into two neuronal subpopulations forming the direct and indirect pathways, which project to the Substantia Nigra pars reticulata (SNr) or the external segment of the Globus Pallidus (GPe) respectively. The activation of these two pathways induces opposite regulation of thalamic nuclei, the final target of BG circuits, and their balance is thought to be the mechanism underlying the wide range of BG functions. Key modulators of BG circuits are dopaminergic fibers which originate from Substantia Nigra pars compacta (SNc) and exert opposite effects on MSNs belonging to direct or indirect pathway. However, the involvement of the ECS in the modulation of striatal activity and functions is poorly investigated. The project presented in my PhD thesis aimed at understand the distinct role of CB1 receptors in direct or indirect striatal MSNs. In particular, using viral and/or genetic manipulations to specifically target striatal CB1 receptors, we investigated the involvement of these receptors in mediating the action of THC or amphetamine, which are known to act on striatal physiology. Interestingly, we found a specific involvement of CB1 receptors located in direct vs indirect striatal pathways in mediating the behavioral effects of these drugs. Within the same brain circuit different subcellular pools of CB1 receptors are involved in different neurophysiological functions (neurotransmitter vs neuropeptide release), and therefore their activation mediates different synaptic and behavioral effects. Our results highlight new specific roles for CB1 receptors depending on their location, circuit and/or subcellular compartments, in mediating the action of drugs of abuse, representing a new target for specific treatmentsLe système endocannabinoïde (ECS) est un réseau de neuromodulation impliqué dans un large éventail de fonctions physiologiques. Il est composé d’endocannabinoïdes, les récepteurs et les enzymes impliquées dans leurs biosynthèses et dégradations. Dans le système nerveux central l’action des endocannabinoïdes est principalement régulée par le récepteur cannabinoïde de type 1 (CB1), un GPCR à sept domaines transmembranaires exprimé de manière quasi ubiquitaire, situé dans plusieurs types de cellules mais aussi dans différents compartiments subcellulaires, à savoir les mitochondries. Les récepteurs CB1 sont également la cible principale des phytocannabinoïdes tels que le Δ-9-tétrahydrocannabinol (THC), le principal composé psycho-actif de la plante Cannabis Sativa. Lors d'une activation physiologique ou pharmacologique, les récepteurs CB1 modulent l'excitabilité neuronale et la libération de neurotransmetteurs, jouant ainsi un rôle crucial dans la transmission synaptique et la plasticité. L’un des pools les plus importants de récepteurs CB1 dans le cerveau est situé dans le striatum, la structure principale des ganglions de la base (BG). Les BG sont un groupe de noyaux sous-corticaux impliqués dans les boucles cortico-thalamique-corticales nécessaires aux comportements adaptatifs tels que la coordination motrice, l’apprentissage des habiletés motrices et la formation des mémoires procédurales. Le striatum, principalement composé de neurones épineux moyens (MSNs) GABAergiques, intègre les entrées glutamatergiques provenant des zones corticales et des noyaux thalamiques et module leur activité via ses structures cibles. Les MSNs sont divisés en deux populations neuronales formant les circuits direct et indirect, qui diffèrent pour leur région cible, respectivement Substantia Nigra pars reticulata (SNr) et Globus Pallidus externe (GPe). L’activation de ces deux voies induit une régulation opposée des noyaux thalamiques, cible finale des circuits des BG, et leur équilibre est considéré comme le mécanisme qui permet un large éventail de fonctions des BG. Les fibres dopaminergiques, qui proviennent de la Substantia Nigra pars compacta (SNc) sont un modulateur clé des circuits striataux. Le projet présenté dans ma thèse de doctorat visait à comprendre le rôle des récepteurs CB1 situés dans les différentes voies striatales. En particulier, en utilisant des manipulations virales et/ou génétiques pour cibler les récepteurs CB1 striataux, nous avons étudié leur implication dans l’action du THC ou de l’amphétamine, qui sont connus pour agir sur la physiologie striatale. De manière intéressante, nous avons trouvé une implication spécifique des récepteurs CB1 situés dans la voie directe ou indirecte dans la médiation des effets comportementaux et synaptiques de ces drogues. De plus, nous avons constaté qu’au sein d’un même circuit cérébral, différents pools subcellulaires de récepteurs CB1 sont impliqués dans différentes fonctions neurophysiologiques (libération de neurotransmetteur ou neuropeptides), et que leur activation entraîne donc des effets synaptiques et comportementaux différents. Nos résultats mettent en évidence des nouveaux rôles spécifiques des récepteurs CB1 en fonction de leur localisation, du circuit et/ou des compartiments subcellulaires, dans la médiation de l’action des drogues d’abus, représentant une nouvelle cible pour des traitements spécifique

Role of type-1 cannabinoid receptor in basal ganglia physiology

Le système endocannabinoïde (ECS) est un réseau de neuromodulation impliqué dans un large éventail de fonctions physiologiques. Il est composé d’endocannabinoïdes, les récepteurs et les enzymes impliquées dans leurs biosynthèses et dégradations. Dans le système nerveux central l’action des endocannabinoïdes est principalement régulée par le récepteur cannabinoïde de type 1 (CB1), un GPCR à sept domaines transmembranaires exprimé de manière quasi ubiquitaire, situé dans plusieurs types de cellules mais aussi dans différents compartiments subcellulaires, à savoir les mitochondries. Les récepteurs CB1 sont également la cible principale des phytocannabinoïdes tels que le Δ-9-tétrahydrocannabinol (THC), le principal composé psycho-actif de la plante Cannabis Sativa. Lors d'une activation physiologique ou pharmacologique, les récepteurs CB1 modulent l'excitabilité neuronale et la libération de neurotransmetteurs, jouant ainsi un rôle crucial dans la transmission synaptique et la plasticité. L’un des pools les plus importants de récepteurs CB1 dans le cerveau est situé dans le striatum, la structure principale des ganglions de la base (BG). Les BG sont un groupe de noyaux sous-corticaux impliqués dans les boucles cortico-thalamique-corticales nécessaires aux comportements adaptatifs tels que la coordination motrice, l’apprentissage des habiletés motrices et la formation des mémoires procédurales. Le striatum, principalement composé de neurones épineux moyens (MSNs) GABAergiques, intègre les entrées glutamatergiques provenant des zones corticales et des noyaux thalamiques et module leur activité via ses structures cibles. Les MSNs sont divisés en deux populations neuronales formant les circuits direct et indirect, qui diffèrent pour leur région cible, respectivement Substantia Nigra pars reticulata (SNr) et Globus Pallidus externe (GPe). L’activation de ces deux voies induit une régulation opposée des noyaux thalamiques, cible finale des circuits des BG, et leur équilibre est considéré comme le mécanisme qui permet un large éventail de fonctions des BG. Les fibres dopaminergiques, qui proviennent de la Substantia Nigra pars compacta (SNc) sont un modulateur clé des circuits striataux. Le projet présenté dans ma thèse de doctorat visait à comprendre le rôle des récepteurs CB1 situés dans les différentes voies striatales. En particulier, en utilisant des manipulations virales et/ou génétiques pour cibler les récepteurs CB1 striataux, nous avons étudié leur implication dans l’action du THC ou de l’amphétamine, qui sont connus pour agir sur la physiologie striatale. De manière intéressante, nous avons trouvé une implication spécifique des récepteurs CB1 situés dans la voie directe ou indirecte dans la médiation des effets comportementaux et synaptiques de ces drogues. De plus, nous avons constaté qu’au sein d’un même circuit cérébral, différents pools subcellulaires de récepteurs CB1 sont impliqués dans différentes fonctions neurophysiologiques (libération de neurotransmetteur ou neuropeptides), et que leur activation entraîne donc des effets synaptiques et comportementaux différents. Nos résultats mettent en évidence des nouveaux rôles spécifiques des récepteurs CB1 en fonction de leur localisation, du circuit et/ou des compartiments subcellulaires, dans la médiation de l’action des drogues d’abus, représentant une nouvelle cible pour des traitements spécifiquesThe endocannabinoid system (ECS) is a neuromodulatoy network involved in a wide range of physiological functions. ECS comprises endocannabinoids, receptors, and enzymes involved in their synthesis and degradation. In the CNS the action of endocannabinoids is mainly mediated by the cannabinoid type-1 (CB1) receptor, a seven-transmembrane GPCR expressed almost ubiquitously, located in several cell types but also in subcellular compartments, i.e. mitochondria and plasma membranes. CB1 receptors are also the main target of phytocannabinoids such as Δ-9-tetrahydrocannabinol (THC), the main psycho-active compound of the plant Cannabis Sativa. Upon physiological or pharmacological activation, CB1 receptors can modulate neuronal excitability and neurotransmitter release, playing a crucial role in the regulation of synaptic transmission and plasticity. One of the highest pools of CB1 receptors in the brain is located in the striatum, the main structure of Basal Ganglia (BG). BG are a group of subcortical nuclei involved in cortico-thalamic-cortical loops necessary for adaptive behaviors such as motor coordination, motor skills learning, and procedural memory formations. The striatum, mainly composed by GABAergic medium spiny projection neurons (MSNs), represents the input structure of BG receiving glutamatergic inputs rising from cortical areas and thalamic nuclei. MSNs are segregated into two neuronal subpopulations forming the direct and indirect pathways, which project to the Substantia Nigra pars reticulata (SNr) or the external segment of the Globus Pallidus (GPe) respectively. The activation of these two pathways induces opposite regulation of thalamic nuclei, the final target of BG circuits, and their balance is thought to be the mechanism underlying the wide range of BG functions. Key modulators of BG circuits are dopaminergic fibers which originate from Substantia Nigra pars compacta (SNc) and exert opposite effects on MSNs belonging to direct or indirect pathway. However, the involvement of the ECS in the modulation of striatal activity and functions is poorly investigated. The project presented in my PhD thesis aimed at understand the distinct role of CB1 receptors in direct or indirect striatal MSNs. In particular, using viral and/or genetic manipulations to specifically target striatal CB1 receptors, we investigated the involvement of these receptors in mediating the action of THC or amphetamine, which are known to act on striatal physiology. Interestingly, we found a specific involvement of CB1 receptors located in direct vs indirect striatal pathways in mediating the behavioral effects of these drugs. Within the same brain circuit different subcellular pools of CB1 receptors are involved in different neurophysiological functions (neurotransmitter vs neuropeptide release), and therefore their activation mediates different synaptic and behavioral effects. Our results highlight new specific roles for CB1 receptors depending on their location, circuit and/or subcellular compartments, in mediating the action of drugs of abuse, representing a new target for specific treatment

Striatopallidal cannabinoid type-1 receptors mediate amphetamine-induced sensitization

Repeated exposure to psychostimulants, such as amphetamine, causes a long-lasting enhancement in the behavioral responses to the drug, called behavioral sensitization.1 This phenomenon involves several neuronal systems and brain areas, among which the dorsal striatum plays a key role.2 The endocannabinoid system (ECS) has been proposed to participate in this effect, but the neuronal basis of this interaction has not been investigated.3 In the CNS, the ECS exerts its functions mainly acting through the cannabinoid type-1 (CB1) receptor, which is highly expressed at terminals of striatal medium spiny neurons (MSNs) belonging to both the direct and indirect pathways.4 In this study, we show that, although striatal CB1 receptors are not involved in the acute response to amphetamine, the behavioral sensitization and related synaptic changes require the activation of CB1 receptors specifically located at striatopallidal MSNs (indirect pathway). These results highlight a new mechanism of psychostimulant sensitization, a phenomenon that plays a key role in the health-threatening effects of these drugs

Vulnerable newborn types: analysis of subnational, population‐based birth cohorts for 541 285 live births in 23 countries, 2000–2021

Objective: To examine prevalence of novel newborn types among 541 285 live births in 23 countries from 2000 to 2021. Design: Descriptive multi-country secondary data analysis. Setting: Subnational, population-based birth cohort studies (n = 45) in 23 low- and middle-income countries (LMICs) spanning 2000–2021. Population: Liveborn infants. Methods: Subnational, population-based studies with high-quality birth outcome data from LMICs were invited to join the Vulnerable Newborn Measurement Collaboration. We defined distinct newborn types using gestational age (preterm [PT], term [T]), birthweight for gestational age using INTERGROWTH-21st standards (small for gestational age [SGA], appropriate for gestational age [AGA] or large for gestational age [LGA]), and birthweight (low birthweight, LBW [<2500 g], nonLBW) as ten types (using all three outcomes), six types (by excluding the birthweight categorisation), and four types (by collapsing the AGA and LGA categories). We defined small types as those with at least one classification of LBW, PT or SGA. We presented study characteristics, participant characteristics, data missingness, and prevalence of newborn types by region and study. Results: Among 541 285 live births, 476 939 (88.1%) had non-missing and plausible values for gestational age, birthweight and sex required to construct the newborn types. The median prevalences of ten types across studies were T+AGA+nonLBW (58.0%), T+LGA+nonLBW (3.3%), T+AGA+LBW (0.5%), T+SGA+nonLBW (14.2%), T+SGA+LBW (7.1%), PT+LGA+nonLBW (1.6%), PT+LGA+LBW (0.2%), PT+AGA+nonLBW (3.7%), PT+AGA+LBW (3.6%) and PT+SGA+LBW (1.0%). The median prevalence of small types (six types, 37.6%) varied across studies and within regions and was higher in Southern Asia (52.4%) than in Sub-Saharan Africa (34.9%). Conclusions: Further investigation is needed to describe the mortality risks associated with newborn types and understand the implications of this framework for local targeting of interventions to prevent adverse pregnancy outcomes in LMICs

Vulnerable newborn types: analysis of subnational, population‐based birth cohorts for 541 285 live births in 23 countries, 2000–2021

Setting: Subnational, population-based birth cohort studies (n = 45) in 23 low-and middle-income countries (LMICs) spanning 2000–2021. Population: Liveborn infants. Methods: Subnational, population-based studies with high-quality birth outcome data from LMICs were invited to join the Vulnerable Newborn Measurement Collaboration. We defined distinct newborn types using gestational age (preterm [PT], term [T]), birthweight for gestational age using INTERGROWTH-21st standards (small for gestational age [SGA], appropriate for gestational age [AGA] or large for gestational age [LGA]), and birthweight (low birthweight, LBW [<2500 g], non- LBW) as ten types (using all three outcomes), six types (by excluding the birthweight categorisation), and four types (by collapsing the AGA and LGA categories). We defined small types as those with at least one classification of LBW, PT or SGA. We presented study characteristics, participant characteristics, data missingness, and prevalence of newborn types by region and study. Results: Among 541 285 live births, 476 939 (88.1%) had non-missing and plausible values for gestational age, birthweight and sex required to construct the newborn types. The median prevalences of ten types across studies were T+AGA+nonLBW (58.0%), T+LGA+nonLBW (3.3%), T+AGA+LBW (0.5%), T+SGA+nonLBW (14.2%), T+SGA+LBW (7.1%), PT+LGA+nonLBW (1.6%), PT+LGA+LBW (0.2%), PT+AGA+nonLBW (3.7%), PT+AGA+LBW (3.6%) and PT+SGA+LBW (1.0%). The median prevalence of small types (six types, 37.6%) varied across studies and within regions and was higher in Southern Asia (52.4%) than in Sub-Saharan Africa (34.9%). Conclusions: Further investigation is needed to describe the mortality risks associated with newborn types and understand the implications of this framework for local targeting of interventions to prevent adverse pregnancy outcomes in LMICs