Biology subjects

Moigneu, C.

Publications and source records attributed to Moigneu, C..

3 recordsLinked to original sources

bioRxiv2024

Dissecting the contribution of vagal subcircuits in sepsis-induced brain dysfunctions.

Sepsis, a life-threatening syndrome caused by a dysregulated host response to infection, induces a range of acute effects on the brain, including sickness behaviour and sepsis-associated encephalopathy. In addition, sepsis can lead to durable changes in neuronal circuits, resulting in long-term impairments such as post-traumatic stress disorder (PTSD). These brain dysfunctions are not directly caused by brain infection but result from peripheral inflammatory signals relayed to the brain via neural and humoral pathways. The vagal complex in the brainstem, composed of the nucleus of the solitary tract (NTS) and the area postrema, plays a crucial role in sensing and relaying these signals. Notably, the activation of the vagal complex triggers neurovegetative, neuroendocrine, and behavioural responses to infection. Chronic electrical vagus nerve stimulation has been used clinically to treat various brain disorders and is being investigated for its potential to alleviate inflammation and immune diseases through the anti-inflammatory reflex. However, a deeper understanding of the involvement of the vagus nerve and downstream brain circuits in sepsis-induced brain activation and dysfunction is needed to optimize therapeutic strategies. To investigate the role of the vagal complex in sepsis-induced brain dysfunction, various techniques were employed to manipulate vagus nerve activity and downstream circuits in a rodent model of sepsis by caecal ligation and puncture. Subdiaphragmatic vagotomy and pharmacogenetic manipulation of NTS and nodose (i.e. vagus sensory neurons) were implemented, revealing that vagotomy effectively reduced acute brain activation, inflammatory responses, and sickness behaviour triggered by sepsis. Additionally, transient activation of NTS neurons had a significant impact on inflammatory responses, sickness behaviour, and long-term PTSD-like consequences. This study underscores the complex interplay among the vagus nerve, brain circuits, and systemic inflammation during sepsis, emphasizing the critical importance of understanding these interactions in the development of targeted therapeutic interventions.

neuroscience↗

bioRxiv2023

Basolateral amygdala circuits supporting negative emotional bias in a mouse model for depression

Negative emotional bias is an essential hallmark of depression reflected by negative shift in hedonic valence assignment to emotional stimuli. Pleasant cues become less attractive and unpleasant ones more aversive. Given the crucial role of amygdala in valence coding, we hypothesize that specific basolateral amygdala (BLA) circuits alterations might support negative emotional bias associated with depressive states. Using a translational assay, we evaluate odor valence assignment in an animal model for depression chronically administered by corticosterone (CORT). We show spontaneous negative bias in depressive-like mice that attribute more negative valences for both attractive and aversive odors, mimicking thus the bias observed in depressed bipolar patients. Combining CTB and rabies-based tracing with ex vivo measurements of neuronal activity and chemogenetics experiments, we find that the CORT treatment reduces BLA-to-nucleus accumbens (NAc) neuronal activity and increases BLA-to-central amygdala activity, circuits respectively known to be involved in positive and negative valence encoding. Alterations in presynaptic connectivity of BLA-projecting neurons accompany these activity shifts. Interestingly, inputs from the paraventricular thalamus nucleus (PVT) towards BLA-to-NAc neurons are reduced in CORT-treated mice. Finally, chemogenetically activating the BLA-to-NAc circuit attenuates the negative bias in CORT-treated mice as well as the depressive-like phenotype, similarly than Fluoxetine antidepressant treatment. Altogether, we demonstrate that depressive states are associated with negative emotional bias both in human and mice. This bias is supported by activity shifts of specific BLA circuits along with durable presynaptic connectivity changes, but it could be alleviated by antidepressant drug or activity manipulation of altered BLA circuit.

neuroscience↗

bioRxiv2019

Gut microbiota requires vagus nerve integrity to promote depression

Chronic stress constitutes one of the strongest risk factors for depression and can disrupt various aspects of homeostasis, including gut microbiota composition. We found that stress-induced changes in gut microbiota promote depression and decrease adult hippocampal neurogenesis upon transfer to antibiotic-treated recipient mice. Subdiaphragmatic vagotomy abrogated the microbiota-induced effects on behavior and neurogenesis, suggesting that gut microbiota can influence brain plasticity and behavior through vagal afferents.

neuroscience↗