Biology subjects

Eid, R. S.

Publications and source records attributed to Eid, R. S..

5 recordsLinked to original sources

bioRxiv2024

Data-driven analysis identifies female-specific social modulation deficit after chronic social defeat stress

BackgroundChronic social defeat stress is a widely used depression model in male mice. Several proposed adaptations extend this model to females with variable, often marginal effects. We examine the if widely used male-defined metrics of stress are suboptimal in females and reveal sex-specific adaptations. MethodsUsing a data-driven method we comprehensively classified social interaction behavior in 761 male and female mice after chronic social witness/defeat stress, examining social modulation of behavioral frequencies and associations with conventional metrics (i.e., social interaction (SI) ratio). ResultsSocial stress induces distinct behavioral adaptation patterns in males and females. SI ratio leads to underpowered analyses in females with limited utility to differentiate susceptibility/resilience. Data-driven analyses reveal failure of social adaptation in stressed female mice that is captured in attenuated velocity change from no target to target tests ({Delta}Velocity) and validate this in three female social stress models. Combining SI ratio and {Delta}Velocity optimally differentiates susceptibility/ resilience in females and this metric reveals resilient-specific adaptation in a resilience-associated neural circuit in female mice. ConclusionsWe demonstrate that psychological or physical social defeat stress induces similar deficits in females that is qualitatively distinct from male deficits and inadequately sampled by male-defined metrics. We identify modulation of locomotion as a robust and easily implementable metric for rigorous research in female mice. Overall, our findings highlight the need to critically evaluate sex differences in behavior and implement sex-based considerations in preclinical model design.

neuroscience↗

bioRxiv2022

Sexually dimorphic neural encoding of threat discrimination in nucleus accumbens afferents drives suppression of reward behavior

Learning to predict threat is essential but equally important yet often overlooked is learning about the absence of threat. Interrogating neural activity in two nucleus accumbens afferents in male and female mice during aversive and neutral cues reveals sex-specific encoding of cue discrimination and cuemediated suppression of reward behavior. Sexual dimorphisms in neural bases of threat discrimination may reflect sex differences in behavioral strategy relevant to differential psychiatric risk.

neuroscience↗

bioRxiv2020

Postpartum fluoxetine increased maternal hippocampal IL-1β and decreased plasma tryptophan: clues for efficacy

Perinatal depression (PND) affects approximately 15% of women, and de novo postpartum depression affects approximately 40% of PND cases. Selective serotonin reuptake inhibitors (SSRIs) are a common class of antidepressants prescribed to treat PND. However, the safety and efficacy of SSRIs have been questioned in both clinical and preclinical research. Here, using a preclinical rodent model of postpartum depression, we aim to better understand neuroinflammatory cytokines and tryptophan mechanisms that may be related to SSRIs efficacy. Rodent dams were treated with high corticosterone (CORT; 40mg/kg, s.c.) for 21 days in the postpartum period to simulate depressive-like behaviors in the late postpartum period. Concurrently, a subset of dams was treated with the SSRI, fluoxetine (FLX; 10mg/kg, s.c.), in the postpartum period. We showed, consistent with previous studies, that although maternal FLX treatment prevented CORT-induced disturbances in maternal care behavior during the early postpartum, it failed to prevent the expression of CORT-induced depressive-like behavior in the late postpartum. Furthermore, FLX treatment, regardless of CORT treatment, increased maternal hippocampal IL-1{beta} and decreased maternal plasma tryptophan levels, plasma tryptophan, 4-pyridoxic acid, and pyridoxal concentrations. Maternal CORT treatment reduced maternal hippocampal TNF- and IFN-{gamma} levels. Our work suggests that the limited efficacy of FLX in the late postpartum may be associated with elevated levels of the proinflammatory cytokine IL-1{beta} in the maternal hippocampus, decreased plasma tryptophan concentration, and changes in vitamin B6 dependent tryptophan-kynurenine pathway. These findings suggest novel pathways for improving SSRI efficacy in alleviating perinatal depression. HIGHLIGHTSO_LIPostpartum fluoxetine (FLX) increased interleukin-1{beta} levels in hippocampus C_LIO_LIPostpartum corticosterone (CORT) decreased TNF- and IFN-{gamma} in the hippocampus C_LIO_LIPostpartum FLX did not prevent CORT-induced depressive-like behavior C_LIO_LIPostpartum FLX prevented CORT-induced changes in maternal behavior C_LIO_LIPostpartum FLX decreased plasma tryptophan, 4-pyridoxic acid, and pyridoxal levels C_LI

neuroscience↗

bioRxiv2019

Selective activation of estrogen receptors α and β: Implications for depressive-like phenotypes in female mice exposed to chronic unpredictable stress

The estrogen receptor (ER) mechanisms by which 17{beta}-estradiol influences depressive-like behaviour have primarily been investigated acutely and not within an animal model of depression. Therefore, the current study aimed to dissect the contribution of ER and ER{beta} to the effects of 17{beta}-estradiol under non-stress and chronic stress conditions. Ovariectomized (OVX) or sham-operated mice were treated chronically (47 days) with 17{beta}-estradiol (E2), the ER{beta} agonist diarylpropionitrile (DPN), the ER agonist propylpyrazole-triol (PPT), or vehicle. On day 15 of treatment, mice from each group were assigned to Chronic Unpredictable Stress (CUS; 28 days) or non-CUS conditions. Mice were assessed for anxiety- and depressive-like behaviour and hypothalamic-pituitary-adrenal (HPA) axis function. Cytokine and chemokine levels, and postsynaptic density protein 95 were measured in the hippocampus and frontal cortex, and adult hippocampal neurogenesis was assessed. Overall, the effects of CUS were more robust that those of estrogenic treatments, as seen by increased immobility in the tail suspension test (TST), reduced PSD-95 expression, reduced neurogenesis in the ventral hippocampus, and HPA axis negative feedback dysregulation. However, we also observe CUS-dependent and -independent effects of ovarian status and estrogenic treatments. The effects of CUS on PSD-95 expression, the cytokine milieu, and in TST were largely driven by PPT and DPN, indicating that these treatments were not protective. Independent of CUS, estradiol increased neurogenesis in the dorsal hippocampus, blunted the corticosterone response to an acute stressor, but increased anxiety-like behaviour. These findings provide insights into the complexities of estrogen signaling in modulating depressive-like phenotypes under non-stress and chronic stress conditions.

neuroscience↗

bioRxiv2019

Ovarian hormone status dictates the neuroinflammatory and behavioural consequences of sub-chronic stress exposure in middle-aged female mice

Ovarian hormones influence the outcomes of stress exposure and are implicated in stress-related disorders including depression, yet their roles are often complex and seemingly contradictory. Importantly, depression and stress exposure are associated with immune dysregulation, and ovarian hormones have immunomodulatory properties. However, how ovarian hormones can influence the inflammatory outcomes of stress exposure is poorly understood. Here, we examined the effects of long-term ovariectomy on the behavioral and neuroinflammatory outcomes of sub-chronic stress exposure in middle-aged mice. Briefly, sham-operated and ovariectomized mice were assigned to non-stress groups or exposed to 6 days of variable stress. Mice were assessed on a battery of behavioral tests, and cytokine concentrations were quantified in the frontal cortex and hippocampus. In the frontal cortex, postsynaptic density protein-95 expression was examined as an index of excitatory synapse number and/or stability, and phosphorylated mitogen-activated protein kinases (MAPKs) were measured to explore potential cell signaling pathways elicited by stress exposure and/or ovarian hormones. Long-term ovariectomy modified the central cytokine profile by robustly reducing cytokine concentrations in the frontal cortex and modestly increasing concentrations in the hippocampus. Under non-stress conditions, long-term ovariectomy also reduced extracellular signal-regulated kinase (ERK) phosphoprotein expression in the frontal cortex and increased some measures of depressive-like behavior. The effects of sub-chronic stress exposure were however more pronounced in sham-operated mice. Notably, in sham-operated mice only, sub-chronic stress exposure increased IL-1{beta} and IL-6:IL-10 ratio in the frontal cortex and hippocampus and reduced pERK1/2 expression in the frontal cortex. Further, although sub-chronic stress exposure increased anhedonia-like behavior regardless of ovarian status, it increased passive-coping behavior in sham-operated mice only. These data indicate that long-term ovariectomy has potent effects on the central cytokine milieu and dictates the neuroinflammatory and behavioral effects of sub-chronic stress exposure in middle-aged mice. These findings therefore suggest that the immunomodulatory properties of ovarian hormones are of relevance in the context of stress and possibly depression.

neuroscience↗