Biology subjects

Audet, M.-C.

Publications and source records attributed to Audet, M.-C..

3 recordsLinked to original sources

bioRxiv2026

Postnatal maternal separation alters caregiving patterns but fails to promote anxiety- and depressive-like behaviour in C57BL/6N mouse dams

Stressors experienced during the postnatal period may increase vulnerability to mental health disorders, including postpartum depression and anxiety. In rodents, maternal separation (MS) has been shown to alter behaviours in dams, but these observations have been made almost exclusively in rats and thus robust mouse models of postpartum mental health disorders using this stressor remain limited. Here we first examined, in mice, the effects of MS on maternal caregiving and on anxiety- and depressive-like behaviours. As stress-induced inflammatory activation in the gut-brain axis has been associated with behavioural alterations in non-postpartum contexts, changes in pro-inflammatory cytokines and tight junction proteins in the brain and intestinal tract were also examined. Female C57BL/6N mice were assigned to a No Separation (NS) or a MS condition that consisted of 3-hour daily separation sessions from postnatal days (P) 2 to 14. Maternal care behaviours were assessed on P3 and P7, followed by anxiety- and depressive-like behaviours on P22 and P23, and the collection of the medial prefrontal cortex (mPFC) and colon on P24 to determine the expression of selected genes. Caregiving patterns in MS dams fluctuated throughout the early postnatal period. Although behaviours and gene expression outcomes remained unchanged by MS, grooming time in the splash test was correlated with the expression of different genes in the mPFC. These findings suggest that C57BL/6 mouse dams may be less sensitive to the actions of MS on behaviour and on brain and intestinal markers of inflammation and barrier permeability, at least when examined shortly after weaning.

animal behavior and cognition↗

bioRxiv2022

Sex-specific effects of voluntary wheel running on behavior and the gut microbiota-immune-brain axis in mice

Physical exercise has been positioned as a promising strategy to prevent and/or alleviate anxiety and depression, but the mechanisms underlying its effects on mental health have yet to be entirely determined. Although the prevalence of depression and anxiety in women is about twice that of men, very few studies have examined whether physical exercise could affect mental health differently according to sex. This study examined, in mice, the sex-specific effects of voluntary exercise on body weight, depressive- and anxiety-like behaviors, as well as different markers along the gut microbiota-immune-brain axis. Male and female C57BL/6N mice had voluntary access to running wheels in their home-cages for 24 days or were left undisturbed in identical home-cages without running wheels. Behaviors were then examined in the open field, Splash, elevated plus maze, and tail suspension tests. Gene expression of pro-inflammatory cytokines, microglia activation-related genes, and tight junction proteins was determined in the jejunum and the hippocampus, while microbiota composition and predicted function were verified in cecum contents. Voluntary exercise limited weight gains, reduced anxiety-like behaviors, and altered grooming patterns in males exclusively. Although the exercise intervention resulted in changes to brain inflammatory activity and to cecal microbiota composition and inferred function in both sexes, reductions in the jejunal expression of pro-inflammatory markers were observed in females only. These findings support the view that voluntary exercise, even when performed during a short period, is beneficial for mental and intestinal health and that its sex-specific effects on behavior could be, at least in part, mediated by the gut microbiota-immune-brain axis.

neuroscience↗

bioRxiv2022

Chronic stress exposure alters the gut barrier: sex-specific effects on microbiota and jejunum tight junctions

Major depressive disorder (MDD) is the leading cause of disability worldwide. However, 30-50% of patients are unresponsive to commonly prescribed antidepressants, highlighting untapped causal biological mechanisms. Dysfunction in the microbiota-gut-brain axis, the bidirectional communications between the central nervous system and gastrointestinal tract that are modulated by gut microorganisms, has been implicated in MDD pathogenesis. Exposure to chronic stress disrupts blood-brain barrier integrity, still, little is known about intestinal barrier function in these conditions particularly for the small intestine where most food and drug absorption takes place. Thus, here we investigate how chronic social or variable stress, two mouse models of depression, impact the jejunum (JEJ) intestinal barrier in males and females. Mice were subjected to stress paradigms followed by analysis of gene expression profiles of intestinal barrier-related targets, fecal microbial composition, and blood-based markers. Altered microbial populations as well as changes in gene expression of JEJ tight junctions were observed depending on the type and duration of stress, with sex-specific effects. We took advantage of machine learning to characterize in detail morphological tight junction properties identifying a cluster of ruffled junctions in stressed animals. Junctional ruffling is associated with inflammation, so we evaluated if LPS injection recapitulates stress-induced changes in the JEJ and observed profound sex differences. Finally, LPS-binding protein (LBP), a marker of gut barrier leakiness, was associated with stress vulnerability in mice and translational value was confirmed on blood samples from women with MDD. Our results provide evidence that chronic stress disrupts intestinal barrier homeostasis in conjunction with the manifestation of depressive-like behaviors in a sex-specific manner in mice and possibly, human depression.

neuroscience↗