Stress Response In Mice Research Articles

Effects of an Chinese Herbal Compound Prescription on Simulated Transport Stress in Mice

Background: In order to alleviate the transport stress reaction of animals, three kinds of chinese herbs with sedative and tranquilizing properties were extracted with ethanol and proportionally composed into a chinese herbal compound prescription. In addition, isorhynchophylline in leaves of Uncaria rhynchophylla was isolated and purified for use. Methods: The enzyme-linked Immunosorbent assay (ELISA) was used to measure the changes in serum stress indicators and hormone levels, three classification blood cell counter and automatic biochemistry analyser was used to measure blood indicators and other biochemical indicators of each group mice before and after transport stress. Result: The results showed that the blood physiological indexes such as blood glucose (GLU) level, biochemical indexes such as lactate dehydrogenase (LDH) and hormone levels such as adrocorticotropic hormone (ACTH) and other stress indexes were significantly higher in mice after transport than before. The compound agents and isorhynchophylline played a role in regulating the stress indices of mice after the simulating transport processs and have the effect of significantly alleviating the transport stress response in mice, with a view to provide reference for alleviating the adverse effects of transport stress on the animal husbandry industry.

Noradrenaline release from the locus coeruleus shapes stress-induced hippocampal gene expression.

Exposure to an acute stressor triggers a complex cascade of neurochemical events in the brain. However, deciphering their individual impact on stress-induced molecular changes remains a major challenge. Here, we combine RNA sequencing with selective pharmacological, chemogenetic, and optogenetic manipulations to isolate the contribution of the locus coeruleus-noradrenaline (LC-NA) system to the acute stress response in mice. We reveal that NA release during stress exposure regulates a large and reproducible set of genes in the dorsal and ventral hippocampus via β-adrenergic receptors. For a smaller subset of these genes, we show that NA release triggered by LC stimulation is sufficient to mimic the stress-induced transcriptional response. We observe these effects in both sexes, and independent of the pattern and frequency of LC activation. Using a retrograde optogenetic approach, we demonstrate that hippocampus-projecting LC neurons directly regulate hippocampal gene expression. Overall, a highly selective set of astrocyte-enriched genes emerges as key targets of LC-NA activation, most prominently several subunits of protein phosphatase 1 (Ppp1r3c, Ppp1r3d, Ppp1r3g) and type II iodothyronine deiodinase (Dio2). These results highlight the importance of astrocytic energy metabolism and thyroid hormone signaling in LC-mediated hippocampal function and offer new molecular targets for understanding how NA impacts brain function in health and disease.

Reducing branched-chain amino acids improves cardiac stress response in mice by decreasing histone H3K23 propionylation.

Identification of branched-chain amino acid (BCAA) oxidation enzymes in the nucleus led us to predict that they are a source of the propionyl-CoA that is utilized for histone propionylation and, thereby, regulate gene expression. To investigate the effects of BCAAs on the development of cardiac hypertrophy and failure, we applied pressure overload on the heart in mice maintained on a diet with standard levels of BCAAs (BCAA control) versus a BCAA-free diet. The former was associated with an increase in histone H3K23-propionyl (H3K23Pr) at the promoters of upregulated genes (e.g., cell signaling and extracellular matrix genes) and a decrease at the promoters of downregulated genes (e.g., electron transfer complex [ETC I-V] and metabolic genes). Intriguingly, the BCAA-free diet tempered the increases in promoter H3K23Pr, thus reducing collagen gene expression and fibrosis during cardiac hypertrophy. Conversely, the BCAA-free diet inhibited the reductions in promoter H3K23Pr and abolished the downregulation of ETC I-V subunits, enhanced mitochondrial respiration, and curbed the progression of cardiac hypertrophy. Thus, lowering the intake of BCAAs reduced pressure overload-induced changes in histone propionylation-dependent gene expression in the heart, which retarded the development of cardiomyopathy.

Environmental conditions of recognition memory testing induce neurovascular changes in the hippocampus in a sex-specific manner in mice

Experiences are linked to emotions impacting memory consolidation and associated brain neuronal circuits. Posttraumatic stress disorder is an example of strong negative emotions affecting memory processes by flashbacks of past traumas. Stress-related memory deficits are also observed in major depressive disorder (MDD). We recently highlighted that sex-specific blood-brain barrier (BBB) alterations underlie stress responses in mice and human depression. However, little is known about the relationship between emotional valence, memory encoding and BBB gene expression. Here, we investigated the effects of novel object recognition (NOR) test, an experience considered of neutral emotional valence, on BBB properties in dorsal vs ventral hippocampus (HIPP) in the context of various environmental conditions (arena size, handling, age). The HIPP is a brain area central for learning and memory processes with the dorsal and ventral subregions being associated with working memory vs reference memory retrieval, respectively. Expression of genes related to BBB integrity are altered in line with learning and memory processes in a region- and sex-specific manner. We observed correlations between poor learning, anxiety, stress-induced corticosterone release and changes in BBB-associated gene expression. Comparison of BBB transcriptomes between sexes also revealed profound differences at baseline in both ventral and dorsal HIPP. Finally, we identified circulating vascular biomarkers, such as sE-selectin and matrix metallopeptidase 9 (MMP-9), altered following NOR exposure supporting that recognition memory formation has an impact on the neurovasculature. Although deemed as a neutral valence test, NOR experimental conditions can shift it toward a negative valence, impacting performance and highlighting the need to minimize anxiety when performing this commonly used test in mice.

Metabolic and Transcriptomic Signatures of the Acute Psychological Stress Response in the Mouse Brain

Acute stress response triggers various physiological responses such as energy mobilization to meet metabolic demands. However, the underlying molecular changes in the brain remain largely obscure. Here, we used a brief water avoidance stress (WAS) to elicit an acute stress response in mice. By employing RNA-sequencing and metabolomics profiling, we investigated the acute stress-induced molecular changes in the mouse whole brain. The aberrant expression of 60 genes was detected in the brain tissues of WAS-exposed mice. Functional analyses showed that the aberrantly expressed genes were enriched in various processes such as superoxide metabolism. In our global metabolomic profiling, a total of 43 brain metabolites were significantly altered by acute WAS. Metabolic pathways upregulated from WAS-exposed brain tissues relative to control samples included lipolysis, eicosanoid biosynthesis, and endocannabinoid synthesis. Acute WAS also elevated the levels of branched-chain amino acids, 5-aminovalerates, 4-hydroxy-nonenal-glutathione as well as mannose, suggesting complex metabolic changes in the brain. The observed molecular events in the present study provide a valuable resource that can help us better understand how acute psychological stress impacts neural functions.

Sexually dimorphic role of the locus coeruleus PAC1 receptors in regulating acute stress-associated energy metabolism.

Severe stress leads to alterations in energy metabolism with sexually dimorphic onset or severity. The locus coeruleus (LC) in the brainstem that mediates fight-or-flight-or-freeze response to stress is sexually dimorphic in morphology, plays a key role in interactions between diet and severe stressors, and has neuronal input to the brown adipose tissue (BAT)—a thermogenic organ important for energy balance. Yet, little is known on how LC coordinates stress-related metabolic adaptations. LC expresses receptors for the neuropeptide PACAP (pituitary adenylate cyclase activating peptide) and PACAP signaling through PAC1 (PACAP receptor) are critical regulators of various types of stressors and energy metabolism. We hypothesized that LC-PAC1 axis is a sex-specific central “gatekeeper” of severe acute stress-driven behavior and energy metabolism. Selective ablation of PAC1 receptors from the LC did not alter stress response in mice of either sex, but enhanced food intake in females and was associated with increased energy expenditure and BAT thermogenesis in male mice. These results show a sexually dimorphic role of the LC-PAC1 in regulating acute stress-related energy metabolism. Thus, by disrupting LC-PAC1 signaling, our studies show a unique and previously unexplored role of LC in adaptive energy metabolism in a sex-dependent manner.

Effects of dietary acetaminophen, vitamin C and thioctic acid supplements on stress responses in mice vaccinated with foot-and-mouth disease vaccine

Effects of dietary acetaminophen, vitamin C and thioctic acid supplements on stress responses in mice vaccinated with foot-and-mouth disease vaccine

Sustained TNF signaling is required for the synaptic and anxiety-like behavioral response to acute stress

Acute stress triggers plasticity of forebrain synapses as well as behavioral changes. Here we reveal that Tumor Necrosis Factor α (TNF) is a required downstream mediator of the stress response in mice, necessary for stress-induced synaptic potentiation in the ventral hippocampus and for an increase in anxiety-like behaviour. Acute stress is sufficient to activate microglia, triggering the long-term release of TNF. Critically, on-going TNF signaling specifically in the ventral hippocampus is necessary to sustain both the stress-induced synaptic and behavioral changes, as these could be reversed hours after induction by antagonizing TNF signaling. This demonstrates that TNF maintains the synaptic and behavioral stress response in vivo, making TNF a potential novel therapeutic target for stress disorders.

FMRP protects the lung from xenobiotic stress by facilitating the integrated stress response.

Stress response pathways protect the lung from the damaging effects of environmental toxicants. Here we investigate the role of the fragile X mental retardation protein (FMRP), a multifunctional protein implicated in stress responses, in the lung. We report that FMRP is expressed in murine and human lungs, in the airways and more broadly. Analysis of airway stress responses in mice and in a murine cell line ex vivo, using the well-established naphthalene injury model, reveals that FMRP-deficient cells exhibit increased expression of markers of oxidative and genotoxic stress and increased cell death. Further inquiry shows that FMRP-deficient cells fail to actuate the integrated stress response pathway (ISR) and upregulate the transcription factor ATF4. Knockdown of ATF4 expression phenocopies the loss of FMRP. We extend our analysis of the role of FMRP to human bronchial BEAS-2B cells, using a 9,10-phenanthrenequinone air pollutant model, to find that FMRP-deficient BEAS-2B cells also fail to actuate the ISR and exhibit greater susceptibility. Taken together, our data suggest that FMRP has a conserved role in protecting the airways by facilitating the ISR. This article has an associated First Person interview with the first author of the paper.

Multiomic profiling of the acute stress response in the mouse hippocampus

The acute stress response mobilizes energy to meet situational demands and re-establish homeostasis. However, the underlying molecular cascades are unclear. Here, we use a brief swim exposure to trigger an acute stress response in mice, which transiently increases anxiety, without leading to lasting maladaptive changes. Using multiomic profiling, such as proteomics, phospho-proteomics, bulk mRNA-, single-nuclei mRNA-, small RNA-, and TRAP-sequencing, we characterize the acute stress-induced molecular events in the mouse hippocampus over time. Our results show the complexity and specificity of the response to acute stress, highlighting both the widespread changes in protein phosphorylation and gene transcription, and tightly regulated protein translation. The observed molecular events resolve efficiently within four hours after initiation of stress. We include an interactive app to explore the data, providing a molecular resource that can help us understand how acute stress impacts brain function in response to stress.

Differential impact of JUUL flavors on pulmonary immune modulation and oxidative stress responses in male and female mice.

JUUL is a popular e-cigarette brand that manufactures e-liquids in a variety of flavors, such as mango and mint. Despite their popularity, the pulmonary effects of flavored JUUL e-liquids that are aerosolized and subsequently inhaled are not known. Therefore, the purpose of this study was to evaluate if acute exposure to JUUL e-cigarette aerosols in three popular flavors elicits an immunomodulatory or oxidative stress response in mice. We first developed a preclinical model that mimics human use patterns of e-cigarettes using 1puff/min or 4puffs/min exposure regimes. Based on cotinine levels, these exposures were representative of light/occasional and moderate JUUL users. We then exposed C57BL/6 mice to JUUL e-cigarette aerosols in mango, mint, and Virginia tobacco flavors containing 5% nicotine for 3days, and assessed the inflammatory and oxidative stress response in the lungs and blood. In response to the 1puff/min regime (light/occasional user), there were minimal changes in BAL cell composition or lung mRNA expression. However, at 4puffs/min (moderate user), mint-flavored JUUL significantly increased lung neutrophils, while mango-flavored JUUL significantly increased Tnfα and Il13 mRNA in the lungs. Both the 1- and 4puffs/min regimes significantly increased oxidative stress markers in the blood, indicating systemic effects. Thus, JUUL products are not inert; even short-term inhalation of flavored JUUL e-cigarette aerosols differentially causes immune modulation and oxidative stress responses.

Tet1-mediated modulation of Alzheimer's disease.

Human sequencing studies have identified roughly 30 risk loci associated Alzheimer's disease (AD). However, these loci only explain a portion of disease pathogenicity. Recent studies support a link between gene-environment interactions and AD, and published work from our lab indicates Tet1 mediates gene-environment interactions and Tet1 KO reduces stress response in mice [1]. Furthermore, DNA deep sequencing studies identified an enrichment of rare Tet2 variants associated with AD [2]. This study examines how knockout of the Tet1, a DNA 5-hydroxymethylcytosine (5hmC) regulator, influences AD-associated transcription and pathological outcomes in the 5xFAD AD mouse model. We measured cognitive/behavioral, 5hmC, and expression profiles of a Tet1 heterozygous knockout in the 5xFAD mouse model to examine the influences of Tet1 KO on AD pathogenicity. We show significant differences in behavior, cognition, 5hmC methylation and expression profiles of FAD/Tet1+/- mice relative to WT and FAD. In relation to FAD, FAD/Tet1+/- improved stress response in the Tail-Suspension Assay (p = 0.0438), and relative to WT mice, FAD/Tet1+/- mice display a reduction in their latency to mount the platform in the Morris water maze (p = 0.01). Analysis of 5hmC capture data revealed 2536 differentially hydroxymethylated regions (DhMRs) upregulated in FADTet1 and 410 DhMRs downregulated relative FAD (FDR > 0.05). Analysis of the expression data highlighted 132 differentially expressed genes (DEGs) in FAD/Tet1+/- relative to FAD (FDR > 0.05). Among the genes exclusive to the FAD/Tet1 mice were Nr4A1, Arc, and APLP1. Notably, Nr4A1 appeared in both the 5hmC and RNA-Seq data with increased levels of 5hmC and gene expression relative to FAD mice. Gene ontology analysis of RNA expression data identified significant changes in pathways involved in regulation of ion transmembrane transport, behavioral fear response, regulation of trans-synaptic signaling, and learning or memory. Taken together, these results suggest Tet1 modulates AD-associated gene regulation, expression and pathology.

Intestinal microbiota modulates adrenomedullary response through Nod1 sensing in chromaffin cells

SummaryThe intestinal microbiota closely interacts with the neuroendocrine system and exerts profound effects on host physiology. Here, we report that nucleotide-binding oligomerization domain 1 (Nod1) ligand derived from intestinal bacteria modulates catecholamine storage and secretion in mouse adrenal chromaffin cells. The cytosolic peptidoglycan receptor Nod1 is involved in chromogranin A (Chga) retention in dense core granules (DCGs) in chromaffin cells. Mechanistically, upon recognizing its ligand, Nod1 localizes to DCGs, and recruits Rab2a, which is critical for Chga and epinephrine retention in DCGs. Depletion of Nod1 ligand or deficiency of Nod1 leads to a profound defect in epinephrine storage in chromaffin cells and subsequently less secretion upon stimulation. The intestine-adrenal medulla cross talk bridged by Nod1 ligand modulates adrenal medullary responses during the immobilization-induced stress response in mice. Thus, our study uncovers a mechanism by which intestinal microbes modulate epinephrine secretion in response to stress, which may provide further understanding of the gut-brain axis.

Evaluation of CVC1302 for Improved Efficacy of FMD-Inactivated Vaccine in Oxidative Stressed Mice Generated with PCV2 Infection.

This study aimed to explore the effect of the immunopotentiator CVC1302 on foot-and-mouth disease (FMD) vaccination in animals placed under oxidative stress. We established oxidative stress models using porcine circovirus type 2 (PCV2)-infected PK-15 cells and mice model both in vitro and in vivo, respectively. The efficacy of CVC1302 on PK-15 cells or in addition to the FMD vaccine was evaluated by quantitative real-time polymerase chain reaction, histopathological and enzyme-linked immunosorbent assay (ELISA) analysis. CVC1302 affected apoptosis of PCV2-infected PK-15 cells and significantly inhibited PCV2 replication, while it had no effect on the viability for blank PK-15 cell in vitro test with varying dilutions of CVC1302. Results showed that PCV2 induced a strong oxidative stress response in mice. CVC1302 reduced the viral load in spleen of PCV2-infected mice and ameliorated the pathological injury of spleen. Furthermore, CVC1302 significantly increased IgG antibody titer, cytokine expression, superoxide dismutase activity, catalase concentrations, and glutathione content in mice immunized with FMD vaccine. In conclusion, CVC1302 inhibits PCV2 replication and regulates oxidative stress in PCV2-infected mice, which can improve the immune efficacy of the FMD vaccine, providing a safe and effective immune enhancement.

Acute stress reveals different impacts in male and female Zdhhc7-deficient mice

Numerous processes of neuronal development and synaptic plasticity in the brain rely on the palmitoyl acyltransferase ZDHHC7, as it palmitoylates various synaptic and extrasynaptic proteins such as neural cell adhesion molecule (NCAM) or gamma-aminobutyric acid (GABAA) receptors. In addition, ZDHHC7 palmitoylates sex steroid hormone receptors and is, therefore, indirectly linked to mental disorders that often occur because of or in conjunction with stress. In this work, we investigated how ZDHHC7 affects stress responses in mice. For this purpose, genetically modified mice with a knockout of the Zdhhc7 gene (KO) and wild-type (WT) littermates of both sexes were exposed to acute stressors or control conditions and examined with regard to their behavior, brain microstructure, gene expression, and synaptic plasticity. While no behavioral effects of acute stress were found, we did find that acute stress caused reduced mRNA levels of Esr1 and Esr2 coding for estrogen receptor α and β in the medial prefrontal cortex of male WT and KO mice. Strikingly, after acute stress only male KO mice showed reduced mean fiber lengths of the medioventral hippocampus. Furthermore, Zdhhc7-deficiency impaired synaptic plasticity in mice of both sexes, while acute stress improved it in females, but not in male mice. Taken together, our findings suggest that ZDHHC7 plays a modulatory role in the brain that leads to sex-specific stress responses, possibly due to estrogen receptor-mediated signaling pathways.

Possible Involvement of MyD88 in Regulating Stress Response in Mice.

Myeloid differentiation primary response 88 (MyD88) is an adapter protein of the toll-like receptor (TLR) family that regulates innate immune function. Here, we identified a novel role of MyD88 in regulating stress response. MyD88 deficiency decreased immobility time in the forced swim test without affecting locomotor activity in mice. Immobilization stress-induced production of serum corticosterone was also completely inhibited by MyD88 deficiency. Stress induced decrease in glucocorticoid receptor in the hippocampus. On the other hand, stress exposure in MyD88 deficient mice did not cause decrease in its level in the hippocampus. Furthermore, immobilization stress-induced reduction of brain-derived neurotrophic factor (BDNF) levels in the hippocampus was ameliorated by MyD88 deficiency. These results suggest that MyD88 deficiency attenuates depression-like behavior by regulating corticosterone and BDNF levels. Overall, these results indicate the key role of MyD88 in regulating stress response in mice.

Intestinal Microbiota Modulates Adrenomedullary Response Through Nod1 Sensing in Chromaffin Cells

The intestinal microbiota closely interacts with the neuroendocrine system and exerts profound effects on host physiology. Here we report that Nod1 ligand derived from intestinal bacteria modulates catecholamine storage and secretion in mouse adrenal chromaffin cells. The cytosolic peptidoglycan receptor Nod1 is involved in chromogranin A (Chga) retention in dense core granules (DCGs) in chromaffin cells. Mechanistically, upon recognizing its ligand, Nod1 localizes to DCGs, and recruits Rab2a, which is critical for Chga and epinephrine retention in DCGs. Depletion of Nod1 ligand or deficiency of Nod1 leads to a profound defect in epinephrine storage in chromaffin cells and subsequently less secretion upon stimulation. The intestine-adrenal medulla crosstalk bridged by Nod1 ligand modulates adrenal medullary responses during the immobilization-induced stress response in mice. Thus, our study uncovers a mechanism by which intestinal microbes modulate epinephrine secretion in response to stress, which may provide further understanding of the gut-brain axis.

Identification of 14-3-3 epsilon as a regulator of the neural apoptotic pathway for chronic-stress-induced depression

SummaryMajor depression is a prevalent and long-lasting psychiatric illness with severe functional impairment and high suicide rate. We have previously shown that the ventrolateral orbital cortex (VLO) plays a key role in the stress responses in mice, but the underlying mechanisms remains unclear. Here, we used proteomic method to identify differentially expressed proteins in VLO of chronic unpredictable mild stress (CUMS) mice. Of 4,953 quantified proteins, 45 proteins were differentially expressed following CUMS. The integrated pathway analyses identified 14-3-3ε and TrkB signaling as differentially downregulated in association with stress-induced depressive-like behaviors. 14-3-3ε overexpression in VLO relieved the depressive-like behaviors by rescue of Bad-mediated apoptosis. Moreover, treatment with the 14-3-3ε stabilizer FC-A precluded neuronal apoptotic signaling in VLO of depressed mice. Because 14-3-3ε provides significant protection against chronic stress, boosting 14-3-3ε expression, pharmacological stabilization of 14-3-3s (e.g. with FC-A) is identified as an exciting therapeutic target for major depression.

Relief of Cadmium-Induced Intestinal Motility Disorder in Mice by Lactobacillus plantarum CCFM8610

Cadmium (Cd) is a toxic metal inducing a range of adverse effects on organs including liver and kidneys. However, the underlying molecular mechanisms of Cd-induced intestinal toxicity through dietary intake is poorly studied. This study evaluated the toxic effects of Cd on intestinal physiology and confirmed the effectiveness of the protective mechanism of the probiotic Lactobacillus plantarum CCFM8610 against chronic Cd toxicity. After treatment with Cd, the HT-29 cell line was subjected to iTRAQ analysis, which revealed that changes in the proteomic profiles after Cd exposure were related to pathways involved in the stress response and carbohydrate metabolism. The results of an animal trial also indicated that 10 weeks of Cd exposure decreased the fecal water content and contractile response of colonic muscle strips in mice, and delayed the excretion time of the first black feces. L. plantarum CCFM8610 treatment provided protective effects against these Cd-induced intestinal motility dysfunctions by recovering the levels of neurotransmitters, including substance P, acetyl cholinesterase, vasoactive intestinal peptide, 5-hydroxytryptamine, calcitonin gene-related peptide, and nitric oxide, and suppressing the cellular stress response in mice (e.g., the inhibition of mitogen-activated protein kinase pathways). The administration of this probiotic was also observed to reduce Cd levels in the tissues and blood of the mice. Our results suggest a newly identified protective mechanism of probiotics against Cd toxicity that involves the recovery of intestinal motility and increase in fecal cadmium excretion.

Ablation of NPFFR2 in Mice Reduces Response to Single Prolonged Stress Model

Mental stress is highly related to many clinical symptoms and disorders, as it activates the hypothalamic-pituitary-adrenocortical (HPA) axis to affect a wide variety of physiological functions. Furthermore, stress leads to the aberrations in HPA axis activity and disruptions of body homeostasis. It was previously shown that neuropeptide FF (NPFF) regulates the HPA axis through the activation of hypothalamus paraventricular nucleus (PVN), and genetic overexpression or pharmacological stimulation of NPFF receptor 2 (NPFFR2) triggers hyperactivity of HPA axis and suppresses behavioral correlates of emotion in mice. In this study, we further examined the role of NPFFR2 in stress response in mice by utilizing a single prolonged stress (SPS). SPS is considered a model of post-traumatic stress disorder (PTSD), and mice undergo physical restraint, forced swimming, and ether anesthesia within a day followed by social isolation for one week. NPFFR2 knockout B6 mice were generated by CRISPR/Cas9 technology and exposed to SPS. The NPFFR2 knockouts showed resistance to stress exposure-induced anxiety-like behaviors and HPA axis hyperactivity. Additionally, the hippocampal mRNA levels of glucocorticoid receptor and mineralocorticoid receptor were reduced in wild-type (WT) mice but not in NPFFR2 knockouts after stress exposure. Our data also suggested that NPFFR2 knockout mice have stronger negative feedback on the HPA axis after exposure to SPS. Mice with intra-PVN Npffr2 shRNA injection displayed trends toward resistance to SPS exposure in both behavioral and molecular assays. Together, our findings suggest that NPFFR2 may be a potential therapeutic target for disorders relating to stress/anxiety and HPA dysregulation.