Synaptic and cellular endocannabinoid signaling mechanisms regulate stress-induced plasticity of nucleus accumbens somatostatin neurons

Metabolomic profiles in serum uncover novel biomarkers in children with Williams-Beuren syndrome

Williams-Beuren syndrome (WBS, OMIM-no.194050) is a rare congenital genetic disorder primarily marked by developmental delays and cardiovascular anomalies, with potential involvement of metabolic dysregulation. Despite this, the metabolic features of WBS have not been extensively studied. Thus, our objective was to examine the serum metabolome profile in children with WBS, elucidating metabolic changes and associated pathways in the disorder. We recruited 25 children with WBS (mean age 5.0 ± 2.6 years, 40% female) from the Children's Hospital affiliated to Zhejiang University between 2020 and 2023. An age and sex matched healthy control group (N = 25) were recruited from the Health Management Center in the same hospital. Clinical information of WBS were extracted from the medical records. Blood samples were obtained for untargeted metabolomics analysis using UPLC-MS/MS. The metabolomic profiles of WBS patients were compared to those of healthy controls to identify metabolites with differential abundance. Enrichment analysis was conducted to identify potentially impacted KEGG pathways. Associations between metabolites and phenotypes were evaluated. Children with WBS exhibited a unique metabolic profile compared to healthy controls, as evidenced by the identification of 465 untargeted metabolites in serum. Of these metabolites, 169 showed differential abundance in WBS children. The top enriched KEGG pathways in WBS children included nicotine addiction, cholesterol metabolism, arginine biosynthesis, retrograde endocannabinoid signaling. Additionally, there were indications of potential metabolic alterations in the L-tryptophan pathway, with a shift from serotonin to L-kynurenine, as well as disruptions in bile acid metabolism. Metabolome data in children with WBS showed neurological and amino acid metabolism changes, indicating multisystem involvement and developmental delay. This data can help monitor and manage the disease, but further studies are needed to understand the underlying mechanisms and consequences.

Cannabinoid Modulation of Central Amygdala Population Dynamics During Threat Investigation

Cannabinoids modulate innate avoidance, threat-reactivity, and stress adaptations via modulation amygdala-associated circuits; however, the mechanisms by which cannabinoids modulate amygdala representation of threat-related behavior are not known. We show that cannabinoid administration increases the activity of central amygdala (CeA) somatostatin neurons (SOM) and alters basal network dynamics in a manner supporting generation of antagonistic sub-ensembles within the SOM population. Moreover, diverging neuronal population trajectory dynamics and enhanced antagonistic sub-ensemble representation of threat-related behaviors, and enhanced threat-related location representation, were also observed. Lastly, cannabinoid administration increased the proportion of SOM neurons exhibiting multidimensional representation of threat-related behaviors and behavior-location conjunction. While cannabinoid receptor activation ex vivo suppressed excitatory inputs to SOM neurons, our data suggest preferential suppression of local GABA release subserves cannabinoid activation of CeA SOM neurons. These data provide insight into how cannabinoid-mediated presynaptic suppression transforms postsynaptic population dynamics and reveal cellular mechanisms by which cannabinoids could affect threat-reactivity.

Endocannabinoids facilitate transitory reward engagement through retrograde gain-control

Neuromodulatory signaling is poised to serve as a neural mechanism for gain control, acting as a crucial tuning factor to influence neuronal activity by dynamically shaping excitatory and inhibitory fast neurotransmission. The endocannabinoid (eCB) signaling system, the most widely expressed neuromodulatory system in the mammalian brain, is known to filter excitatory and inhibitory inputs through retrograde, pre-synaptic action. However, whether eCBs exert retrograde gain control to ultimately facilitate reward-seeking behaviors in freely moving mammals is not established. Using a suite of in vivo physiological, imaging, genetic and machine learning-based approaches, we report a fundamental role for eCBs in controlling behavioral engagement in reward-seeking behavior through a defined thalamo-striatal circuit.

CB1R activates the epilepsy-associated protein Go to regulate neurotransmitter release and synaptic plasticity in the cerebellum

GNAO1 encodes the alpha subunit of the heterotrimeric Go protein. Despite being the most abundant G protein at synapses, the role of Go in the brain remains unclear, primarily because of the high mortality associated with developmental and epileptic encephalopathy (DEE) 17 in Gnao1 mutated animals. Here, we conducted proteomic analyses with a brain synaptosomal fraction to investigate the Go-interactome and then generated a non-DEE model using Gli1CreERT2 mice to selectively knockout (KO) the presynaptic Gαo within cerebellum. Our findings revealed that Gαo interacts with multiple proteins involved in neurotransmitter release, as well as cannabinoid receptor type 1 (CB1R), a key Gi/o-coupled receptor in presynaptic terminals. In Gnao1 KO mice, synapse formation was reduced in the cerebellum with a concomitant reduction in depolarization-induced suppression of excitation, a manifestation of CB1R-mediated synaptic plasticity found in the cerebellum. These mice displayed motor deficits in rotarod, grip strength, gait, and beam balance tests. Our results suggest that Go plays a critical role in regulating neurotransmitter releases at the presynaptic terminals and its absence in the entire brain may contribute to DEE pathogenesis. This study also provides valuable insights into the signaling pathways in the brain from a Go-dependent perspective.

Alcohol Withdrawal Alters the Inhibitory Landscape of the Prelimbic Cortex in an Interneuron- and Sex-specific Manner

Alcohol use disorder (AUD) is highly prevalent and associated with substantial morbidity and high mortality among substance use disorders. While there are currently three FDA-approved medications for treating AUDs, none specifically target the withdrawal/negative affect stage of AUD, underscoring the need to understand the underlying neurobiology during this critical stage of the addiction cycle. One key region involved in alcohol withdrawal and negative affect is the prelimbic cortex, a subregion of the medial prefrontal cortex. While previous studies have examined alcohol-related adaptations in prefrontal cortical principal glutamatergic neurons, here we used male and female PV:Ai14, SOM:Ai14 and VIP:Ai14 mice to examine synaptic adaptations in all three major classes of prelimbic cortex interneurons following 72 hour withdrawal from a continuous access to two bottle choice model of EtOH drinking in male and female mice. We found that alcohol withdrawal increased excitability of prelimbic PV interneurons in males, but decreased excitability in prelimbic VIP interneurons in females. Additionally, alcohol withdrawal reduced GABA release onto PV interneurons in males while increasing glutamate release onto VIP interneurons in females. In SOM interneurons, alcohol withdrawal had no effect on excitability, but decreased glutamate release onto SOM interneurons in males. Together, our studies identified sex-specific alcohol withdrawal-induced synaptic plasticity in three different types of interneurons and could provide insight into the cellular substrates of negative affective states associated with alcohol withdrawal.

The nucleus accumbens in reward and aversion processing: insights and implications

The nucleus accumbens (NAc), a central component of the brain's reward circuitry, has been implicated in a wide range of behaviors and emotional states. Emerging evidence, primarily drawing from recent rodent studies, suggests that the function of the NAc in reward and aversion processing is multifaceted. Prolonged stress or drug use induces maladaptive neuronal function in the NAc circuitry, which results in pathological conditions. This review aims to provide comprehensive and up-to-date insights on the role of the NAc in motivated behavior regulation and highlights areas that demand further in-depth analysis. It synthesizes the latest findings on how distinct NAc neuronal populations and pathways contribute to the processing of opposite valences. The review examines how a range of neuromodulators, especially monoamines, influence the NAc's control over various motivational states. Furthermore, it delves into the complex underlying mechanisms of psychiatric disorders such as addiction and depression and evaluates prospective interventions to restore NAc functionality.

Acute stress modulates hippocampal to entorhinal cortex communication

Feed-forward inhibition is vital in the transfer and processing of synaptic information within the hippocampal-entorhinal loop by controlling the strength and direction of excitation flow between different neuronal populations and individual neurons. While the cellular targets in the hippocampus that receive excitatory inputs from the entorhinal cortex have been well studied, and the role of feedforward inhibitory neurons has been attributed to neurogliafom cells, the cortical interneurons providing feed-forward control over receiving layer V in the entorhinal cortex remain unknown. We used sharp-wave ripple oscillations as a natural excitatory stimulus of the entorhinal cortex, driven by the hippocampus, to study the function of synaptic interactions between neurons in the deep layers of the entorhinal cortex. We discovered that CB1R-expressing interneurons in the deep layers of the entorhinal cortex constitute the major relay station that translates hippocampal excitation into efficient inhibition of cortical pyramidal cells. The impact of inhibition provided by these interneurons is under strong endocannabinoid control and can be drastically reduced either by enhanced activity of postsynaptic targets or by stress-induced elevation of cannabinoids.