LHPP in Glutamatergic Neurons of the Ventral Hippocampus Mediates Depression-like Behavior by Dephosphorylating CaMKIIα and ERK.

BACKGROUND: LHPP was recently shown to be a risk gene for major depressive disorder. LHPP has been proven to dephosphorylate the residues of histidine, serine, threonine, and tyrosine. However, much remains unknown about how LHPP contributes to depression. METHODS: In the current study, we addressed this issue by integrating approaches of genetics, molecular biology, behavioral testing, and electrophysiology. RESULTS: We found that levels of LHPP were upregulated in glutamatergic neurons of the ventral hippocampus in mice that displayed stress-induced depression-like behaviors. Knockout of LHPP in glutamatergic neurons of the brain improved the spontaneous activity of LHPPflox/flox·CaMKIIαCre+ (conditional knockout) mice. Adeno-associated virus-mediated LHPP knockdown in the ventral hippocampus enhanced resistance against chronic social defeat stress in mice. Manipulations of LHPP levels impacted the density of dendritic spines and excitability of CA1 pyramidal neurons by mediating the expressions of BDNF (brain-derived neurotrophic factor) and PSD95 via the modulation of the dephosphorylation of CaMKIIα and ERK. Notably, compared with wild-type LHPP, human mutant LHPP (E56K, S57L) significantly increased the activity of the CaMKIIα/ERK-BDNF/PSD95 signaling pathway. Finally, esketamine, not fluoxetine, markedly alleviated the LHPP upregulation-induced depression-like behaviors. CONCLUSIONS: These findings provide evidence that LHPP contributes to the pathogenesis of depression via threonine and serine hydrolases, thereby identifying LHPP as a potential therapeutic target in treating patients with major depressive disorder.

ApoE4 exacerbates the senescence of hippocampal neurons and spatial cognitive impairment by downregulating acetyl-CoA level.

Although aging and apolipoprotein E (APOE) ε4 allele have been documented as two major risk factors for late-onset Alzheimer's disease (LOAD), their interaction and potential underlying mechanisms remain unelucidated. Using humanized ApoE4- and ApoE3- target replacement mice, we found the accumulation of senescent neurons and the activation of mTOR and endosome-lysosome-autophagy (ELA) system in the hippocampus of aged ApoE4 mice. Further analyses revealed that ApoE4 aggravated the profile change of hippocampal transcription and metabolism in an age-dependent manner, accompanying with an disruption of metabolism, which is presented with the downregulating activity of citrate synthase, the level of ATP and, most importantly, the level of acetyl coenzyme A (Ac-CoA); GTA supplement, an Ac-CoA substrate, reversed the senescent characteristics, decreased the activation of mTOR and ELA system, and enhanced the synaptic structure and increasing level of pre-/post-synaptic plasticity-related protein, leading to cognitive improvement in aged ApoE4 mice. These data suggest that ApoE4 exacerbates neuronal senescence due to a deficiency of acetyl-CoA, which can be ameliorated by GTA supplement. The findings provide novel insights into the potential therapeutic value of GTA supplement for the cognitive improvement in aged APOE4 carriers.

ACSS2-dependent histone acetylation improves cognition in mouse model of Alzheimer's disease.

BACKGROUND: Nuclear acetyl-CoA pools govern histone acetylation that controls synaptic plasticity and contributes to cognitive deterioration in patients with Alzheimer's disease (AD). Nuclear acetyl-CoA pools are generated partially from local acetate that is metabolized by acetyl-CoA synthetase 2 (ACSS2). However, the underlying mechanism of histone acetylation dysregulation in AD remains poorly understood. METHODS: We detected ACSS2 expression and histone acetylation levels in the brains of AD patients and 5 × FAD mice. When we altered ACSS2 expression by injecting adeno-associated virus into the dorsal hippocampus of 5 × FAD mice and replenished ACSS2 substrate (acetate), we observed changes in cognitive function by Morris water maze. We next performed RNA-seq, ChIP-qPCR, and electrophysiology to study molecular mechanism underlying ACSS2-mediated spatial learning and memory in 5 × FAD mice. RESULTS: We reported that ACSS2 expression and histone acetylation (H3K9, H4K12) were reduced in the hippocampus and prefrontal cortex of 5 × FAD mice. Reduced ACSS2 levels were also observed in the temporal cortex of AD patients. 5 × FAD mice exhibited a low enrichment of acetylated histones on the promoters of NMDARs and AMPARs, together with impaired basal and activity-dependent synaptic plasticity, all of which were rescued by ACSS2 upregulation. Moreover, acetate replenishment enhanced ac-H3K9 and ac-H4K12 in 5 × FAD mice, leading to an increase of NMDARs and AMPARs and a restoration of synaptic plasticity and cognitive function in an ACSS2-dependent manner. CONCLUSION: ACSS2 is a key molecular switch of cognitive impairment and that targeting ACSS2 or acetate administration may serve as a novel therapeutic strategy for the treatment of intermediate or advanced AD. Nuclear acetyl-CoA pools are generated partly from local acetate that is metabolized by acetyl-CoA synthetase 2 (ACSS2). Model depicts that ACSS2 expression is downregulated in the brains of 5×FAD model mice and AD patients. Of note, ACSS2 downregulation mediates a reduction in ionotropic glutamate receptor expression through histone acetylation, which exacerbates synaptic plasticity impairment in AD. These deficits can be rescued by ACSS2 upregulation or acetate supplementation (GTA, an FDA-approved food additive), which may serve as a promising therapeutic strategy for AD treatment.

Reflections on the battle against COVID-19: The effects of emotional design factors on the communication of audio-visual art.

Fighting against the epidemic is an arduous and prolonged battle where many artists hope to inspire people with the power of art through cultural creativity. To explore the effects of emotional design factors on the communication of audio-visual art and the audience's perceptive experience, this research takes the original anti-epidemic song and the film China Braves Headwind as the research object. The research also uses such methods as questionnaires, Structural Equation Models, and dependent samples t-tests to conduct statistical analysis. The results are as follows: First, the emotional design evaluation matrix based on the emotional communication model is reasonable, and the scales of this research are feasible. Second, the emotional design of audio-visual works can significantly affect the audience's emotional experience and further improve sharing intention. Third, Attribute A2 (Artistic style, Thematic perception) and attribute C3 (Emotional resonance, Spiritual sublimation) serve as common factors affecting the emotional experience in terms of both musical works and film and television works. Fourth, compared with musical works, film and television works are likely to resonate with the audience. The combination of music and visual sensation can help open up the conception of artistic works and convey their meanings to viewers. Therefore, it's necessary to explore the emotional communication mode between audio-visual artists and the audience. It helps artists think about how to create works innovatively and is conducive to marketizing works and stimulating cultural consumption demand.

Plasma Exosomal CXCL7 is a Potential Biomarker for Lung Adenocarcinoma.

BACKGROUND: Lung cancer is a leading cause of cancer-related death, with lung adenocarcinoma (LUAD) representing the most common subtype. Recently, exosome-based biomarkers have provided new diagnostic approaches for malignancies. METHODS: The differential expression profile of plasma exosomal mRNA was established by high-throughput sequencing, and the expression and diagnostic value of plasma exosomal CXCL7 mRNA and protein in LUAD were studied to evaluate their diagnostic value as tumor biomarkers. RESULTS: The expression of plasma exosomal CXCL7 mRNA in patients with LUAD was significantly increased (p < 0.01), which had no significant correlation with age, gender, and stage. ROC was used to evaluate the diagnostic value of plasma exosomal CXCL7 mRNA in LUAD patients with AUC = 0.7171. Further analysis signified that the CXCL7 protein of plasma exosomes in LUAD patients was overexpressed, and it was positively correlated with TNM stage and age. The diagnostic value of plasma exosomal CXCL7 in LUAD is better than serum CEA, with an AUC of 0.785, which has higher sensitivity and specificity. CONCLUSIONS: This research suggests that plasma exosomal CXCL7 may become an effective biomarker for early diagnosis of LUAD.

Pathogenic Characteristics and Genomic Analysis of a Rare Serotype Salmonella enterica Serovar Moualine Isolated from the Blood.

BACKGROUND: Salmonella is composed of a wide variety of serovars that cause human self-limited gastrointestinal illnesses or invasive infections. Most of the Salmonella strains of clinical isolates belong to the A - F group. In December 2012, a case of invasive infection was caused by a rare Salmonella, Salmonella enterica serovar Moualine (S. Moualine), identified as 047 outside of groups A - F, which was easily missed or misreported. The goal is to ex-plore clinical symptoms and therapies of blood infection caused by S. Moualine and to provide theoretical basis and molecular level date for Salmonella research by analyzing pathogenic characteristics and genome information of S. Moualine. METHODS: The S. Moualine genome was sequenced using a PacBio RS II platform and Illumina HiSeq 4000 platform and analysis for serotyping serovars, ST types, the characterization of antibiotic resistance, virulence and phylogeny. RESULTS: The clinical symptoms were mainly irregular recurrent fever, lasting 1 - 3 weeks, with mild gastrointestinal symptoms. The genome size of S. Moualine was 4,611,151 bp, the serotype was 047 (+), Hy (+), H1,6 (+), and multilocus sequence typing analysis was ST3038. S. Moualine contains the majority of virulence genes. Interestingly, S. Moualine also harbors the rck and Typhi colonization factor (tcf) genes, which may play a role in invasive infection. S. Moualine encodes 17 Salmonella pathogenicity islands and is potentially dangerous to human health. Both phenotypic and genomic characterizations have demonstrated that S. Moualine generally showed low antimicrobial resistance potential. CONCLUSIONS: There were few reports on S. Moualine. According to clinical symptoms and genetic analysis, S. Moualine was predicted to be a highly virulent bacteria and was also potentially dangerous to health of humans. This study highlights that the transparency of global surveillance genomic data could accelerate the understanding of the virulence and antimicrobial resistance makeup of a previously unknown threat.

Ganoderma Lucidum Triterpenoids Improve Maternal Separation-Induced Anxiety- and Depression-like Behaviors in Mice by Mitigating Inflammation in the Periphery and Brain.

Although early life stress (ELS) can increase susceptibility to adulthood psychiatric disorders and produce a greater inflammatory response in a stressful event, targeted preventive and therapeutic drugs still remain scarce. Ganoderma lucidum triterpenoids (GLTs) can exert anti-inflammatory effects in the periphery and central nervous systems. This study employed a combined model of "childhood maternal separation + adulthood sub-stress" to explore whether GLTs may alleviate anxiety- and depression-like behaviors in male and female mice by mitigating inflammation. Male and female pups were separated from their mothers for four hours per day from postnatal day 1 (PND 1) to PND 21; starting from PND 56, GLTs were administered intraperitoneally once daily for three weeks and followed by three days of sub-stress. Results showed that maternal separation increased the anxiety- and depression-like behaviors in both male and female mice, which disappeared after the preemptive GLTs treatment (40 mg/kg) before adulthood sub-stress. Maternal separation up-regulated the pro-inflammatory markers in the periphery and brain, and activated microglia in the prefrontal cortex and hippocampus. All the abnormalities were reversed by GLTs administration, with no adverse effects on immune organ indices, liver, and renal function. Our findings suggest that GLTs can be a promising candidate in treating ELS-induced psychiatric disorders.

Ultrafast charge transfer dynamics in 2D covalent organic frameworks/Re-complex hybrid photocatalyst.

Rhenium(I)-carbonyl-diimine complexes have emerged as promising photocatalysts for carbon dioxide reduction with covalent organic frameworks recognized as perfect sensitizers and scaffold support. Such Re complexes/covalent organic frameworks hybrid catalysts have demonstrated high carbon dioxide reduction activities but with strong excitation energy-dependence. In this paper, we rationalize this behavior by the excitation energy-dependent pathways of internal photo-induced charge transfer studied via transient optical spectroscopies and time-dependent density-functional theory calculation. Under band-edge excitation, the excited electrons are quickly injected from covalent organic frameworks moiety into catalytic RheniumI center within picosecond but followed by fast backward geminate recombination. While under excitation with high-energy photon, the injected electrons are located at high-energy levels in RheniumI centers with longer lifetime. Besides those injected electrons to RheniumI center, there still remain some long-lived electrons in covalent organic frameworks moiety which is transferred back from RheniumI. This facilitates the two-electron reaction of carbon dioxide conversion to carbon monoxide.

APOE4 genotype exacerbates the depression-like behavior of mice during aging through ATP decline.

Population-based studies reveal that apolipoprotein E (APOE) ε4 gene allele is closely associated with late-life depression (LLD). However, its exact role and underlying mechanism remain obscure. The current study found that aged apoE4-targeted replacement (TR) mice displayed obvious depression-like behavior when compared with age-matched apoE3-TR mice. Furthermore, apoE4 increased stress-induced depression-like behaviors, accompanied by declines in the hippocampal 5-HT (1A) radioligand [18F] MPPF uptake evidenced by positron emission tomography (PET). In [18F]-fluorodeoxyglucose PET ([18F]-FDG PET) analyses, the FDG uptake in the prefrontal cortex, temporal cortex and hippocampus of apoE4-TR mice significantly declined when compared with that of apoE3-TR mice after acute stress. Further biochemical analysis revealed that ATP levels in the prefrontal cortex of apoE4-TR mice decreased during aging or stress process and ATP supplementation effectively rescued the depression-like behaviors of elderly apoE4-TR mice. In primary cultured astrocytes from the cortex of apoE-TR mice, apoE4, when compared with apoE3, obviously decreased the mitochondrial membrane potential, mitochondrial respiration, and glycolysis in a culture time-dependent manner. Our findings highlight that apoE4 is a potential risk factor of depression in elderly population by impairing the glucose metabolism, reducing ATP level, and damaging mitochondrial functions in astrocytes, which indicates that in clinical settings ATP supplementation may be effective for elderly depression patients with apoE4 carrier.

Identification of a RNA-Seq Based Prognostic Signature with Seven Immune-Related lncRNAs for Lung Adenocarcinoma.

BACKGROUND: Lung adenocarcinoma (LUAD) is still a worldwide challenge. Accumulated evidence demonstrates that the superiority of immune-related long noncoding RNAs (lncRNAs) are closely connected with tumorigenesis and prognosis of cancer. However, no detailed studies have been conducted to present a reliable signature for predicting prognosis in LUAD patients from the perspective of tumor immunology. The aim of this study was to con-struct a risk score model based on the signature of the group of seven immune-related lncRNAs to predict the prognosis of patients with LUAD. METHODS: We performed a genome-wide analysis of expression profiles in 522 LUAD patients from The Cancer Genome Atlas (TCGA) project to explore the prognostic ability of immune-related lncRNAs. By using Kaplan-Meier analysis, univariate/multivariate Cox regression, receiver operating characteristic curve (ROC), and principal components analysis (PCA), a risk score model was constructed based on the signature of the group of seven immune-related lncRNAs to predict the prognosis of patients with LUAD. RESULTS: Using survival analysis and Cox regression model, we identified a set of seven lncRNAs (LINC00941, FAM83A-AS1, AC026355.1, AC068338.3, AC010980.2, AL365181.2, and AC079949.2) demonstrating an ability to stratify patients into high and low risk groups with significantly different survival outcomes. Moreover, the signature was identified as an independent prognostic factor and significantly associated with the overall survival (OS) of LUAD. The area under curve (AUC) of a ROC curve for the signature of the group of seven immune-related lncRNAs in predicting OS was 0.757. In addition, low-risk and high-risk groups displayed different immune statuses based on PCA. CONCLUSIONS: This study suggested a promising seven prognostic immune-related lncRNAs risk scoring system and may provide new information for immunological treatment in LUAD.

Increased Notch2/NF-κB Signaling May Mediate the Depression Susceptibility: Evidence from Chronic Social Defeat Stress Mice and WKY Rats.

The susceptibility to depression has been attributed to the chronic stress and genetic factors but still fails to identify definite biomarkers. The present study aimed to investigate the role of disrupted Notch signaling in the medial prefrontal cortex of the chronic social defeat stress (CSDS) mice and Wistar Kyoto (WKY) rats. RNA-sequencing and quantitative real-time PCR analyses evidenced the involvement of Notch signaling pathway in depression. Western blotting reported an increased level of Notch2 and NF-κB and a decreased level of Hes1 and Bcl2/Bax ratio both in the susceptible mice when compared with the control or resilient ones and in the depression WKY rats when compared with the Wistar or non-depression WKY groups. Further analysis showed that the above-mentioned changes were significantly correlated with the depression-like behaviors and that the elicited Notch2 strongly correlated with the upregulated NF-κB, not with the downregulated Hes1 or Bcl2/Bax ratio. In conclusion, the increased Notch2/NF-κB signaling in the medial prefrontal cortex may mediate depression susceptibility, providing a potential diagnostic biomarker or therapeutic target for treating major depressive disorder.

Acetate supplementation produces antidepressant-like effect via enhanced histone acetylation.

BACKGROUND: Abnormal energy metabolism is often documented in the brain of patients and rodents with depression. In metabolic stress, acetate serves as an important source of acetyl coenzyme A (Ac-CoA). However, its exact role and underlying mechanism remain to be investigated. METHOD: We used chronic social failure stress (CSDS) to induce depression-like phenotype of C57BL/6J mice. The drugs were administered by gavage. We evaluated the depressive symptoms by sucrose preference test, social interaction, tail suspension test and forced swimming test. The dendritic branches and spine density were detected by Golgi staining, mRNA level was analyzed by real-time quantitative RT-PCR, protein expression level was detected by western blot, and the content of Ac-CoA was detected by ELISA kit. RESULT: The present study found that acetate supplementation significantly improved the depression-like behaviors of mice either in acute forced swimming test (FST) or in CSDS model and that acetate administration enhanced the dendritic branches and spine density of the CA1 pyramidal neurons. Moreover, the down-regulated levels of BDNF and TrkB were rescued in the acetate-treated mice. Of note, chronic acetate treatment obviously lowered the transcription level of HDAC2, HDAC5, HDAC7, HDAC8, increased the transcription level of HAT and P300, and boosted the content of Ac-CoA in the nucleus, which facilitated the acetylation levels of histone H3 and H4. LIMITATIONS: The effect of acetate supplementation on other brain regions is not further elucidated. CONCLUSION: These findings indicate that acetate supplementation can produce antidepressant-like effects by increasing histone acetylation and improving synaptic plasticity in hippocampus.

Metformin ameliorates stress-induced depression-like behaviors via enhancing the expression of BDNF by activating AMPK/CREB-mediated histone acetylation.

BACKGROUND: Metformin, a first-line antiglycemic drug, has been reported to have anti-depressant effects in patients with type 2 diabetes; however, its exact role and underlying mechanism still need to be investigated. METHOD: C57BL/6J mice were subjected to the Chronic social defeat stress (SDS) and drug administration (Control + Vehicle, SDS + Vehicle, SDS + MET (200 mg kg-1), SDS + FLUOX (3 mg kg-1), SDS + MET + FLUOX). And the depression phenotypes were evaluated by the sucrose preference test, social interaction, tail suspension test and forced swimming test. The potential mechanisms underlying the effects of metformin on depression was discussed by using Chromatin immunoprecipitation, Quantitative real-time PCR mRNA expression analysis and Western blot in vivo and in primary cultured hippocampal neurons. RESULT: The metformin treatment counteracted the development of depression-like behaviors in mice suffering SDS when administered alone and enhanced the anti-depressant effect of fluoxetine when combined with fluoxetine. Further RNA sequencing analysis revealed that metformin treatment prevented the transcriptional changes in the medial prefrontal cortex (mPFC) of the animals and Golgi staining indicated favorable morphological changes in the neurite plasticity of CA1 pyramidal neurons, which approximated to those found in unstressed mice. At a molecular level, metformin significantly upregulated the expression of the brain-derived neurotrophic factor (BDNF) by increasing the histone acetylation along with the BDNF promoter, which was attributed to the activation of AMP-activated protein kinase (AMPK) and cAMP-response element binding protein (CREB). CONCLUSION: Our findings suggest that metformin can produce antidepressant effects, which provides empirical insights into the clinical value of metformin in the prevention and therapy of depression.

Metformin treatment improves the spatial memory of aged mice in an APOE genotype-dependent manner.

Aging and apolipoprotein E4 (ApoE4) can increase the risk of cognitive impairment and neurodegenerative disorders, including Alzheimer's disease (AD), and patients with type 2 diabetes mellitus are highly susceptible to cognitive dysfunction. Recent research has indicated that metformin, a prescribed drug for type 2 diabetes, may affect cognitive function; however, findings regarding its efficacy are largely controversial. The current study reported that a 5-mo metformin administration (300 mg/kg/d) starting at 13 mo old improved the spatial memory of ApoE3-target replacement (TR) mice, not ApoE4-TR mice. It found that in aged ApoE3-TR mice, metformin treatment, at a molecular level, inhibited AMPK activity, increased insulin signaling, and activated mammalian target of rapamycin signaling, resulting in an enhanced expression of postsynaptic proteins; but the response of the neuronal AMPK activity and insulin signaling to metformin was blunt in aged ApoE4-TR mice. Meanwhile, metformin treatment also increased the phosphorylation of tau in both ApoE3-TR and ApoE4-TR mice, implying that metformin may have side effects in human. These findings suggest that metformin can improve the cognitive performance of aged mice in an APOE genotype-dependent manner, which provides empirical insights into the clinical value of metformin for ApoE4- and age-related AD prevention and treatment.-Zhang, J., Lin, Y., Dai, X., Fang, W., Wu, X., Chen, X. Metformin treatment improves the spatial memory of aged mice in an APOE genotype-dependent manner.

Distinct and Dynamic ON and OFF Neural Ensembles in the Prefrontal Cortex Code Social Exploration.

The medial prefrontal cortex (mPFC) is important for social behavior, but the mechanisms by which mPFC neurons code real-time social exploration remain largely unknown. Here we utilized miniScopes to record calcium activities from hundreds of excitatory neurons in the mPFC while mice freely explored restrained social targets in the absence or presence of the psychedelic drug phencyclidine (PCP). We identified distinct and dynamic ON and OFF neural ensembles that displayed opposing activities to code real-time behavioral information. We further illustrated that ON and OFF ensembles tuned to social exploration carried information of salience and novelty for social targets. Finally, we showed that dysfunctions in these ensembles were associated with abnormal social exploration elicited by PCP. Our findings underscore the importance of mPFC ON and OFF neural ensembles for proper exploratory behavior, including social exploration, and pave the way for future studies elucidating neural circuit dysfunctions in psychiatric disorders.

Acidic Zeolite†L as a Highly Efficient Catalyst for Dehydration of Fructose to 5-Hydroxymethylfurfural in Ionic Liquid.

Zeolite L was synthesized by the hydrothermal method and post-treated by NH4 exchange to adjust its acidity. The samples were systematic characterized by various techniques including XRD, X-ray fluorescence spectroscopy, N2 adsorption-desorption, scanning electron microscopy, pyridine IR spectroscopy, and NH3 temperature-programmed desorption. The results demonstrated that the NH4 -exchange post-treatment increased the surface area, micropore volume, and acidity of zeolite L. The catalytic performance of the samples was tested in the dehydration of fructose to 5-hydroxymethylfurfural (HMF) in ionic liquid (1-butyl-3-methylimidazolium bromide, [bmim]Br). 99.1 % yield of HMF was obtained when the KL-80 °C-1 h sample (KL zeolite treated with 1 m NH4 NO3 solution at 80 °C for 1 h) was used. The high efficiency could be attributed to the appropriate acid properties of the catalyst. The zeolite catalyst could be reused four times without significant decrease in activity.

Curcumin Ameliorates Memory Decline via Inhibiting BACE1 Expression and ß-Amyloid Pathology in 5×FAD Transgenic Mice.

Alzheimer's disease (AD) is the most common dementia and the trigger of its pathological cascade is widely believed to be the overproduction and accumulation of ß-amyloid protein (Aß) in the affected brain. However, effective AD remedies are still anxiously awaited. Recent evidence suggests that curcumin may be a potential agent for AD treatment. In this study, we used 5×FAD transgenic mice as an AD model to investigate the effects of curcumin on AD. Our results showed that curcumin administration (150 or 300 mg/kg/day, intragastrically, for 60 days) dramatically reduced Aß production by downregulating BACE1 expression, preventing synaptic degradation, and improving spatial learning and memory impairment of 5×FAD mice. These findings suggest that curcumin is a potential candidate for AD treatment.

Early-life stress leads to impaired spatial learning and memory in middle-aged ApoE4-TR mice.

BACKGROUND: Apolipoprotein E (ApoE) is a major lipid carrier that supports lipid transport and injury repair in the brain. The APOE ε4 allele is associated with depression, mild cognitive impairment (MCI) and dementia; however, the precise molecular mechanism through which ApoE4 influences the risk of disease development remains unknown. To address this gap in knowledge, we investigated the potential effects of chronic unpredictable mild stress (CUMS) on ApoE3 and ApoE4 target replacement (ApoE3-TR and ApoE4-TR) mice. RESULTS: All ApoE-TR mice exposed to CUMS at 3 months old recovered from a depression-like state by the age of 12 months. Of note, ApoE4-TR mice, unlike age-matched ApoE3-TR mice, displayed impaired spatial cognitive abilities, loss of GABAergic neurons, decreased expression of Reelin, PSD95, SYN and Fyn, and reduced phosphorylation of NMDAR2B and CREB. CONCLUSION: These results suggest that early-life stress may mediate cognitive impairment in middle-age ApoE4-TR mice through sustained reduction of GABAergic neurons and Reelin expression, which might further diminish the activation of the Fyn/NMDAR2B signaling pathway.