Molecular signatures of astrocytes and microglia maladaptive responses to acute stress are rescued by a single administration of ketamine in a rodent model of PTSD

Stress affects the brain and alters its neuroarchitecture and function; these changes can be severe and lead to psychiatric disorders. Recent evidence suggests that astrocytes and microglia play an essential role in the stress response by contributing to the maintenance of cerebral homeostasis. These cells respond rapidly to all stimuli that reach the brain, including stressors. Here, we used a recently validated rodent model of post-traumatic stress disorder in which rats can be categorized as resilient or vulnerable after acute inescapable footshock stress. We then investigated the functional, molecular, and morphological determinants of stress resilience and vulnerability in the prefrontal cortex, focusing on glial and neuronal cells. In addition, we examined the effects of a single subanesthetic dose of ketamine, a fast-acting antidepressant recently approved for the treatment of resistant depression and proposed for other stress-related psychiatric disorders. The present results suggest a prompt glial cell response and activation of the NF-κB pathway after acute stress, leading to an increase in specific cytokines such as IL-18 and TNF-α. This response persists in vulnerable individuals and is accompanied by a significant change in the levels of critical glial proteins such as S100B, CD11b, and CX43, brain trophic factors such as BDNF and FGF2, and proteins related to dendritic arborization and synaptic architecture such as MAP2 and PSD95. Administration of ketamine 24 h after the acute stress event rescued many of the changes observed in vulnerable rats, possibly contributing to support brain homeostasis. Overall, our results suggest that pivotal events, including reactive astrogliosis, changes in brain trophic factors, and neuronal damage are critical determinants of vulnerability to acute traumatic stress and confirm the therapeutic effect of acute ketamine against the development of stress-related psychiatric disorders.

Chronic restraint stress induces abnormal behaviors in pain sensitivity and cognitive function in mice: the role of Keap1/Nrf2 pathway

Stress is a series of physical and psychological responses to external and internal environmental stimuli. Growing studies have demonstrated the detrimental impacts of acute restraint stress (ARS) and chronic restraint stress (CRS) on animal behavior. However, the related pathogenesis and therapeutic mechanisms remain unclear. Hence, the present study aimed to examine whether unfolded protein response (UPR) and Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2 related factor 2 (Nrf2) pathway are associated with ARS- and CRS- induced abnormal behaviors of pain sensitivity and cognitive function. We here used four behavioral tests to evaluate pain sensitivity and cognitive function in ARS and CRS mice. CRS markedly decreased Paw Withdrawal Mechanical Threshold (PWMT) and Tail-flick Latency (TFL) scores, whereas ARS altered TFL but had no effect on PWMT scores. Additionally, CRS, but not ARS, significantly changed behaviors in nest building behavior and MWMT. Intriguingly, the expression of Keap1 and Nrf2 protein were decreased in the spinal cord and hippocampus in CRS mice, but not in ARS mice. Moreover, neither the ARS nor the CRS groups significantly differed from the control group in terms of endoplasmic reticulum stress (ERS). Taken together, this study demonstrated that CRS could induce abnormal pain sensitivity and cognitive function probably via Keap1/Nrf2 pathway in spinal cord and hippocampus. It is therefore likely that effective intervention of Keap1/Nrf2 pathway may contribute to preventing and treating hyperalgesia and cognitive dysfunction in CRS.

Dopamine-Dependent Ketamine Modulation of Glutamatergic Synaptic Plasticity in the Prelimbic Cortex of Adult Rats Exposed to Acute Stress

Traumatic stress is the main environmental risk factor for the development of psychiatric disorders. We have previously shown that acute footshock (FS) stress in male rats induces rapid and long-lasting functional and structural changes in the prefrontal cortex (PFC), which are partly reversed by acute subanesthetic ketamine. Here, we asked if acute FS may also induce any changes in glutamatergic synaptic plasticity in the PFC 24 h after stress exposure and whether ketamine administration 6 h after stress may have any effect. We found that the induction of long-term potentiation (LTP) in PFC slices of both control and FS animals is dependent on dopamine and that dopamine-dependent LTP is reduced by ketamine. We also found selective changes in ionotropic glutamate receptor subunit expression, phosphorylation, and localization at synaptic membranes induced by both acute stress and ketamine. Although more studies are needed to understand the effects of acute stress and ketamine on PFC glutamatergic plasticity, this first report suggests a restoring effect of acute ketamine, supporting the potential benefit of ketamine in limiting the impact of acute traumatic stress.

Transcriptional Profiling of Rat Prefrontal Cortex after Acute Inescapable Footshock Stress

Stress is a primary risk factor for psychiatric disorders such as Major Depressive Disorder (MDD) and Post Traumatic Stress Disorder (PTSD). The response to stress involves the regulation of transcriptional programs, which is supposed to play a role in coping with stress. To evaluate transcriptional processes implemented after exposure to unavoidable traumatic stress, we applied microarray expression analysis to the PFC of rats exposed to acute footshock (FS) stress that were sacrificed immediately after the 40 min session or 2 h or 24 h after. While no substantial changes were observed at the single gene level immediately after the stress session, gene set enrichment analysis showed alterations in neuronal pathways associated with glia development, glia-neuron networking, and synaptic function. Furthermore, we found alterations in the expression of gene sets regulated by specific transcription factors that could represent master regulators of the acute stress response. Of note, these pathways and transcriptional programs are activated during the early stress response (immediately after FS) and are already turned off after 2 h-while at 24 h, the transcriptional profile is largely unaffected. Overall, our analysis provided a transcriptional landscape of the early changes triggered by acute unavoidable FS stress in the PFC of rats, suggesting that the transcriptional wave is fast and mild, but probably enough to activate a cellular response to acute stress.

Changes at glutamate tripartite synapses in the prefrontal cortex of a new animal model of resilience/vulnerability to acute stress

Stress represents a main risk factor for psychiatric disorders. Whereas it is known that even a single trauma may induce psychiatric disorders in humans, the mechanisms of vulnerability to acute stressors have been little investigated. In this study, we generated a new animal model of resilience/vulnerability to acute footshock (FS) stress in rats and analyzed early functional, molecular, and morphological determinants of stress vulnerability at tripartite glutamate synapses in the prefrontal cortex (PFC). We found that adult male rats subjected to FS can be deemed resilient (FS-R) or vulnerable (FS-V), based on their anhedonic phenotype 24 h after stress exposure, and that these two populations are phenotypically distinguishable up to two weeks afterwards. Basal presynaptic glutamate release was increased in the PFC of FS-V rats, while depolarization-evoked glutamate release and synapsin I phosphorylation at Ser⁹ were increased in both FS-R and FS-V. In FS-R and FS-V rats the synaptic expression of GluN2A and apical dendritic length of prelimbic PFC layers II-III pyramidal neurons were decreased, while BDNF expression was selectively reduced in FS-V. Depolarization-evoked (carrier-mediated) glutamate release from astroglia perisynaptic processes (gliosomes) was selectively increased in the PFC of FS-V rats, while GLT1 and xCt levels were higher and GS expression reduced in purified PFC gliosomes from FS-R. Overall, we show for the first time that the application of the sucrose intake test to rats exposed to acute FS led to the generation of a novel animal model of resilience/vulnerability to acute stress, which we used to identify early determinants of maladaptive response related to behavioral vulnerability to stress.

Involvement of miR-135a-5p Downregulation in Acute and Chronic Stress Response in the Prefrontal Cortex of Rats

Stress is a key risk factor in the onset of neuropsychiatric disorders. The study of the mechanisms underlying stress response is important to understand the etiopathogenetic mechanisms and identify new putative therapeutic targets. In this context, microRNAs (miRNAs) have emerged as key regulators of the complex patterns of gene/protein expression changes in the brain, where they have a crucial role in the regulation of neuroplasticity, neurogenesis, and neuronal differentiation. Among them, miR-135a-5p has been associated with stress response, synaptic plasticity, and the antidepressant effect in different brain areas. Here, we used acute unavoidable foot-shock stress (FS) and chronic mild stress (CMS) on male rats to study whether miR-135a-5p was involved in stress-induced changes in the prefrontal cortex (PFC). Both acute and chronic stress decreased miR-135a-5p levels in the PFC, although after CMS the reduction was induced only in animals vulnerable to CMS, according to a sucrose preference test. MiR-135a-5p downregulation in the primary neurons reduced dendritic spine density, while its overexpression exerted the opposite effect. Two bioinformatically predicted target genes, Kif5c and Cplx1/2, were increased in FS rats 24 h after stress. Altogether, we found that miR-135a-5p might play a role in stress response in PFC involving synaptic mechanisms.

Post-Weaning Treatment with Probiotic Inhibited Stress-Induced Amnesia in Adulthood Rats: The Mediation of GABAergic System and BDNF/c-Fos Signaling Pathways

The current study aimed to examine the effect of post-weaning treatment with probiotics on memory formation under stress during the adult period in male Wistar rats. Considering GABA is a potential mediator between probiotics and the host, the present study also investigated the involvement of the GABAergic system in the probiotic response. The hippocampal and prefrontal cortical (PFC) expression levels of BDNF and c-Fos were also assessed to show whether the treatments affect the memory-related signaling pathway. Three weeks after birth, the post-weaning rats were fed with probiotic water (PW) or tap water (TW) for 2, 3, 4, or 5 weeks. Exposure to acute stress impaired memory formation in a passive avoidance learning task. Feeding the post-weaning animals with probiotic strains (3, 4, or 5 weeks) inhibited stress-induced amnesia of the adult period. Post-training intracerebroventricular (ICV) microinjection of muscimol improved stress-induced amnesia in the animals fed with TW. ICV microinjection of muscimol inhibited probiotic treatment's significant effect on the stress response in the memory task. The expression levels of BDNF and c-Fos in the PFC and the hippocampus were significantly decreased in the stress animal group. The levels of BDNF and c-Fos were increased in the PW/stress animal group. The muscimol response was compounded with the decreased levels of BDNF and c-Fos in the PFC and the hippocampus. Thus, the GABA-A receptor mechanism may mediate the inhibitory effect of this probiotic mixture on stress-induced amnesia, which may be associated with the PFC and hippocampal BDNF/c-Fos signaling changes.

Acute Ketamine Facilitates Fear Memory Extinction in a Rat Model of PTSD Along With Restoring Glutamatergic Alterations and Dendritic Atrophy in the Prefrontal Cortex

Stress represents a major risk factor for psychiatric disorders, including post-traumatic stress disorder (PTSD). Recently, we dissected the destabilizing effects of acute stress on the excitatory glutamate system in the prefrontal cortex (PFC). Here, we assessed the effects of single subanesthetic administration of ketamine (10 mg/kg) on glutamate transmission and dendritic arborization in the PFC of footshock (FS)-stressed rats, along with changes in depressive, anxious, and fear extinction behaviors. We found that ketamine, while inducing a mild increase of glutamate release in the PFC of naïve rats, blocked the acute stress-induced enhancement of glutamate release when administered 24 or 72 h before or 6 h after FS. Accordingly, the treatment with ketamine 6 h after FS also reduced the stress-dependent increase of spontaneous excitatory postsynaptic current (sEPSC) amplitude in prelimbic (PL)-PFC. At the same time, ketamine injection 6 h after FS was found to rescue apical dendritic retraction of pyramidal neurons induced by acute stress in PL-PFC and facilitated contextual fear extinction. These results show rapid effects of ketamine in animals subjected to acute FS, in line with previous studies suggesting a therapeutic action of the drug in PTSD models. Our data are consistent with a mechanism of ketamine involving re-establishment of synaptic homeostasis, through restoration of glutamate release, and structural remodeling of dendrites.

Two-hour acute restraint stress facilitates escape behavior and learning outcomes through the activation of the Cdk5/GR P S211 pathway in male mice

Acute stress exerts pleiotropic actions on learning behaviors. The induced negative effects are sometimes adopted to measure the efficacy of particular drugs. Until now, there are no detailed experimental data on the time-gradient effects of acute stress. Here, we developed the time gradient acute restraint stress (ARS) model to precisely assess the roles of different restrain times on inducing acute stress. Time gradient ARS facilitates escape behaviors and learning outcomes, peaking at 2 h-ARS and then declining to baseline at 3.5 h-ARS as confirmed by time gradient post-stress data. Furthermore, time gradient ARS activates glucocorticoid receptor (GR) phosphorylation site at Serine211 (P S221) as an inverted V-shaped pattern peaking at 2 h-ARS, whereas that of the GR phosphorylation site at Serine226 (P S226) from 2 h-ARS to 3.5 h-ARS. The 2 h-ARS but not 3.5 h-ARS enhances synaptic plasticity and genes transcription associated with learning and memory in the hippocampus of male mice. The Cdk5 inhibitor, roscovitine, blocks this facilitation effect by intervening in GR phosphorylation at Serine211 in the 2 h-ARS mice. Altogether, these findings show that the time gradient ARS selectively activates GR phospho-isoforms and differentially influences the behaviors along with maintaining a relationship between 2 h-ARS and Cdk5/GR P S211-mediated transcriptional activity.

Brain-Type Glycogen Phosphorylase Is Crucial for Astrocytic Glycogen Accumulation in Chronic Social Defeat Stress-Induced Depression in Mice

Astrocytic glycogen plays an important role in brain energy metabolism. However, the contribution of glycogen metabolism to stress-induced depression remains unclear. Chronic social defeat stress was used to induce depression-like behaviors in mice, assessed with behavioral tests. Glycogen concentration in the medial prefrontal cortex (mPFC) and the expression of key enzymes of the glycogen metabolism were investigated using Western blots, immunofluorescent staining, electron microscopy, and biochemical assays. Stereotaxic surgery and viral-mediated gene transfer were applied to knockdown or overexpress brain-type glycogen phosphorylase (PYGB) in the mPFC. The glycogen content increased in the mPFC after stress. Glycogenolytic dysfunction due to inactivation of PYGB was responsible for glycogen accumulation. Behavioral tests on astrocyte-specific PYGB overexpression mice showed that augmenting astrocytic PYGB reduces susceptibility to depression when compared with stress-susceptible mice. Conversely, PYGB genetic down-regulation in the mPFC was sufficient to induce glycogen accumulation and depression-like behaviors. Furthermore, PYGB overexpression in the mPFC decreases susceptibility to depression, at least partially by rescuing glycogen phosphorylase activity to maintain glycogen metabolism homeostasis during stress. These findings indicate that (1) glycogen accumulation occurs in mice following stress and (2) glycogenolysis reprogramming leads to glycogen accumulation in astrocytes and PYGB contributes to stress-induced depression-like behaviors. Pharmacological tools acting on glycogenolysis might constitute a promising therapy for depression.

Reduced D-Serine Release May Contribute to Impairment of Long-Term Potentiation by Corticosterone in the Perforant Path-Dentate Gyrus

Long-term potentiation (LTP) is a neurobiological mechanism of cognitive function, and the N-methyl-D-aspartate (NMDA) receptors is fundamental for LTP. Previous studies showed that over activation of NMDA receptors may be a crucial cause of LTP and cognitive impairment induced by stress or corticosterone. However, other studies showed that the function of NMDA receptors is insufficient since the NMDA receptors co-agonist D-serine could improve stress-induced cognitive impairment. The purpose of this study is to clarify whether over activation of NMDA receptors or hypofunction of NMDA receptors is involved in hippocampal impairment of LTP by corticosterone and the underlying mechanisms. Results showed that hippocampal LTP and object location recognition memory were impaired in corticosterone-treated mice. Corticosterone increased the glutamate level in hippocampal tissues, neither NMDA receptors antagonist nor its subtype antagonists alleviated impairment of LTP, while enhancing the function of NMDA receptors by D-serine did alleviate impairment of LTP by corticosterone, suggesting that hypofunction of NMDA receptors might be one of the main reasons for impairment of LTP by corticosterone. Further results showed that the level of D-serine and its precursor L-serine did not change. D-serine release-related protein Na+-independent alanine-serine-cysteine transporter-1 (ASC-1) in the cell membrane was decreased and increasing D-serine release by the selective activator of ASC-1 antiporter activity alleviated impairment of LTP by corticosterone. Taken together, this study demonstrates that hypofunction of NMDA receptors may be involved in impairment of LTP by corticosterone and reduced D-serine release may be an important reason for its hypofunction, which is an important complement to existing mechanisms of corticosterone-induced LTP and cognitive impairment.

The Acute Stress Response in the Multiomic Era

Studying the stress response is a major pillar of neuroscience research not only because stress is a daily reality but also because the exquisitely fine-tuned bodily changes triggered by stress are a neuroendocrinological marvel. While the genome-wide changes induced by chronic stress have been extensively studied, we know surprisingly little about the complex molecular cascades triggered by acute stressors, the building blocks of chronic stress. The acute stress (or fight-or-flight) response mobilizes organismal energy resources to meet situational demands. However, successful stress coping also requires the efficient termination of the stress response. Maladaptive coping-particularly in response to severe or repeated stressors-can lead to allostatic (over)load, causing wear and tear on tissues, exhaustion, and disease. We propose that deep molecular profiling of the changes triggered by acute stressors could provide molecular correlates for allostatic load and predict healthy or maladaptive stress responses. We present a theoretical framework to interpret multiomic data in light of energy homeostasis and activity-dependent gene regulation, and we review the signaling cascades and molecular changes rapidly induced by acute stress in different cell types in the brain. In addition, we review and reanalyze recent data from multiomic screens conducted mainly in the rodent hippocampus and amygdala after acute psychophysical stressors. We identify challenges surrounding experimental design and data analysis, and we highlight promising new research directions to better understand the stress response on a multiomic level.

Metabolomic profiling of anaerobic and aerobic energy metabolic pathways in chronic obstructive pulmonary disease

While there is no cure for chronic obstructive pulmonary disease (COPD), its progressive nature and the formidable challenge to manage its symptoms warrant a more extensive study of the pathogenesis and related mechanisms. A new emphasis on COPD study is the change of energy metabolism. For the first time, this study investigated the anaerobic and aerobic energy metabolic pathways in COPD using the metabolomic approach. Metabolomic analysis was used to investigate energy metabolites in 140 COPD patients. The significance of energy metabolism in COPD was comprehensively explored by the Global Initiative for Chronic Obstructive Lung Disease-GOLD grading, acute exacerbation vs. stable phase (either clinical stability or four-week stable phase), age group, smoking index, lung function, and COPD Assessment Test (CAT) score. Through comprehensive evaluation, we found that COPD patients have a significant imbalance in the aerobic and anaerobic energy metabolisms in resting state, and a high tendency of anaerobic energy supply mechanism that correlates positively with disease progression. This study highlighted the significance of anaerobic and low-efficiency energy supply pathways in lung injury and linked it to the energy-inflammation-lung ventilatory function and the motion limitation mechanism in COPD patients, which implies a novel therapeutic direction for this devastating disease.

Acutely increased β-hydroxybutyrate plays a role in the prefrontal cortex to escape stressful conditions during the acute stress response

Ketone bodies can be increased in the blood under certain physiological conditions, but their role under such conditions remains to be clarified. In the present study, we found the increment and usage of β-hydroxybutyrate (BHB) in the prefrontal cortex (PFC) during acute stress. BHB levels increased in the blood and PFC after 30-min acute immobilization stress, and BHB dehydrogenase 1 increased in the PFC simultaneously, but not in the hippocampus. Moreover, increased levels of acetyl-CoA, pyruvate carboxylase, and glutamate dehydrogenase 1 were found in the PFC, implicating the metabolism of increased BHB in the brain. Thus, we checked the levels of glutamate, glutamine, and GABA and found increased levels of glutamate and glutamine in the stressed group compared with that in the control group in the PFC. Exogenous administration of BHB enhanced struggling behaviors under stressful conditions. Our results suggest that the metabolism of BHB from peripheral blood in the PFC may contribute to acute stress responses to escape stressful conditions.

Sexual dimorphic effects of restraint stress on prefrontal cortical function are mediated by glucocorticoid receptor activation

Stress, a major regulator and precipitating factor of cognitive and emotional disorders, differentially manifests between males and females. Our aim was to investigate the mechanisms underlying the sexual dimorphic effects of acute restraint stress (RS) on males and females on the function of the prefrontal cortex (PFC). Adult male and female mice were subjected to RS or left in their home-cage (NR), and then tested in the light-dark test followed by the temporal order object recognition (TOR) task. Female mice exhibited increased anxiety-like levels, whereas male mice only showed deficits in the TOR task. When the behavioural tests were conducted 24 hr following restraint stress (RS24), only the reduced performance in the TOR task in male mice persisted. In a different cohort, evoked field excitatory postsynaptic potentials (fEPSPs) were recorded in layer II of acute PFC slices, immediately or 24 hr after RS. Long-term potentiation (LTP) was significantly reduced in RS and RS24 male, but not female, compared with their respective NR group. LTP in PFC slices incubated with corticosterone showed significantly reduced LTP only in males. To determine whether glucocorticoid signalling is implicated in the RS-induced behavioural effects, a different cohort of mice was administered mifepristone, a corticosterone receptor antagonist. Mifepristone administration 1 hr before RS prevented the effects of RS on the TOR task in males, but not anxiety. In conclusion, RS has differential effects on recency memory and anxiety, in males and females, which are partly mediated by the effects of corticosterone signalling on synaptic plasticity.

High Fructose Diet Induces Sex-specific Modifications in Synaptic Respiration and Affective-like Behaviors in Rats

The consequences of excessive fructose intake extend beyond those of metabolic disorder to changes in emotional regulation and cognitive function. Long-term consumption of fructose, particularly common when begun in adolescence, is more likely to lead to deleterious consequences than acute consumption. These long-term consequences manifest differently in males and females, suggesting a sex-divergent mechanism by which fructose can impair physiology and neural function. The purpose of the current project was to investigate a possible sex-specific mechanism by which elevated fructose consumption drives behavioral deficits and accompanying metabolic symptoms - specifically, synaptic mitochondrial function. Male and female rats were fed a high fructose diet beginning at weaning and maintained into adulthood. Measures of physiological health across the diet consumption period indicated that females were more likely to gain weight than males while both displayed increased circulating blood glucose. As adults, females fed the high fructose diet displayed increased floating behavior in the forced swim task while males exhibited increased exploratory behavior in the open field. Synaptic respiration was altered by diet in both females and males but the effect was sex-divergent - fructose-fed females had increased synaptic respiration while males showed a decrease. When exposed to an acute energetic challenge, the pattern was reversed. Taken together, these data indicate that diet-induced alterations to neural function and physiology are sex-specific and highlight the need to consider sex as a biological variable when treating metabolic disease. Furthermore, these data suggest that synaptic mitochondrial function may contribute directly to the behavioral consequences of elevated fructose consumption.

Brain glycogen metabolism: A possible link between sleep disturbances, headache and depression

The functions of sleep and its links with neuropsychiatric diseases have long been questioned. Among the numerous hypotheses on sleep function, early studies proposed that sleep helps to replenish glycogen stores consumed during waking. Later studies found increased brain glycogen after sleep deprivation, leading to "glycogenetic" hypothesis, which states that there is a parallel increase in synthesis and utilization of glycogen during wakefulness, whereas decrease in the excitatory transmission creates an imbalance causing accumulation of glycogen during sleep. Glycogen is a vital energy reservoir to match the synaptic demand particularly for re-uptake of potassium and glutamate during intense glutamatergic transmission. Therefore, sleep deprivation-induced transcriptional changes may trigger migraine by reducing glycogen availability, which slows clearance of extracellular potassium and glutamate, hence, creates susceptibility to cortical spreading depolarization, the electrophysiological correlate of migraine aura. Interestingly, chronic stress accompanied by increased glucocorticoid levels and locus coeruleus activity and leading to mood disorders in which sleep disturbances are prevalent, also affects brain glycogen turnover via glucocorticoids, noradrenaline, serotonin and adenosine. These observations altogether suggest that inadequate astrocytic glycogen turnover may be one of the mechanisms linking migraine, mood disorders and sleep.

Mitochondrial gene signature in the prefrontal cortex for differential susceptibility to chronic stress

Mitochondrial dysfunction was highlighted as a crucial vulnerability factor for the development of depression. However, systemic studies assessing stress-induced changes in mitochondria-associated genes in brain regions relevant to depression symptomatology remain scarce. Here, we performed a genome-wide transcriptomic study to examine mitochondrial gene expression in the prefrontal cortex (PFC) and nucleus accumbens (NAc) of mice exposed to multimodal chronic restraint stress. We identified mitochondria-associated gene pathways as most prominently affected in the PFC and with lesser significance in the NAc. A more detailed mitochondrial gene expression analysis revealed that in particular mitochondrial DNA-encoded subunits of the oxidative phosphorylation complexes were altered in the PFC. The comparison of our data with a reanalyzed transcriptome data set of chronic variable stress mice and major depression disorder subjects showed that the changes in mitochondrial DNA-encoded genes are a feature generalizing to other chronic stress-protocols as well and might have translational relevance. Finally, we provide evidence for changes in mitochondrial outputs in the PFC following chronic stress that are indicative of mitochondrial dysfunction. Collectively, our work reinforces the idea that changes in mitochondrial gene expression are key players in the prefrontal adaptations observed in individuals with high behavioral susceptibility and resilience to chronic stress.