PTEN in prefrontal cortex is essential in regulating depression-like behaviors in mice

Hippocampal Crhr1 conditional gene knockout ameliorated the depression-like behavior and pathological damage in male offspring mice caused by chronic stress during pregnancy

Numerous studies have demonstrated that chronic stress during pregnancy (CSDP) can induce depression and hippocampal damage in offspring. It has also been observed that high levels of corticotropin-releasing hormone (CRH) can damage hippocampal neurons, and intraperitoneal injection of a corticotropin releasing hormone receptor 1 (CRHR1) antagonist decreases depression-like behavior and hippocampal neuronal damage in a mouse depression model. However, whether CSDP causes hippocampal damage and depression in offspring through the interaction of CRH and hippocampal CRHR1 remains unknown and warrants further investigation. Therefore, hippocampal Crhr1 conditional gene knockout mice and C57/BL6J mice were used to study these questions. Depression-related indexs in male offspring mice were examined using the forced swim test (FST), sucrose preference test (SPT), tail suspension test (TST) and open field test (OFT). Serum CRH levels were measured by enzyme-linked immunosorbent assay (ELISA). Golgi-Cox staining was used to examine the morphological changes of hippocampal neuronal dendrites. Neuronal apoptosis in the hippocampal CA3 regions was detected by terminal deoxynucleotidy transferase dUTP nick end labeling (TUNEL) staining. The levels of mammalian target of rapamycin (mTOR), phosphorylated mTOR (p-mTOR) and protein kinase B (AKT) proteins were measured by Western blot analysis. This study showed that CSDP induces depression-like behavior, hippocampal neuronal dendrite damage and apoptosis in male offspring mice. Conditional gene knockout of hippocampal Crhr1 in mice reduced CSDP-induced depression-like behavior, hippocampal neuronal dendrite damage and apoptosis in male offspring, and counteracted the CSDP-induced decreased expression of p-Akt and mTOR activity in male offspring hippocampus. These findings demonstrated that CSDP might inhibit the Akt/mTOR pathway by increasing the levels of CRH, leading to increased CRH-mediated activation of hippocampal CRHR1, thereby inducing synaptic impairment and apoptosis in hippocampal neurons, which in turn leads to depression-like behavior in offspring.

Diet induced insulin resistance is due to induction of PTEN expression

Type 2 Diabetes (T2D) is a condition that is often associated with obesity and defined by reduced sensitivity of PI3K signaling to insulin (insulin resistance), hyperinsulinemia and hyperglycemia. Molecular causes and early signaling events underlying insulin resistance are not well understood. Insulin activation of PI3K signaling causes mTOR dependent induction of PTEN translation, a negative regulator of PI3K signaling. We speculated that insulin resistance is due to insulin dependent induction of PTEN protein that prevent further increases in PI3K signaling. Here we show that in a diet induced model of obesity and insulin resistance, PTEN levels are increased in fat, muscle and liver tissues. Onset of hyperinsulinemia and PTEN induction in tissue is followed by hyperglycemia, hepatic steatosis and severe glucose intolerance. Treatment with a PTEN phosphatase inhibitor prevents and reverses these phenotypes, whereas an mTORC1 kinase inhibitor reverses all but the hepatic steatosis. These data suggest that induction of PTEN by increasing levels of insulin elevates feedback inhibition of the pathway to a point where downstream PI3K signaling is reduced and hyperglycemia ensues. PTEN induction is thus necessary for insulin resistance and the type 2 diabetes phenotype and a potential therapeutic target.

Jiao-tai-wan and its effective component-berberine improve diabetes and depressive disorder through the cAMP/PKA/CREB signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Jiao-tai-wan (JTW), a classic herbal formula of traditional Chinese medicine recorded in Han Shi Yi Tong, has been used to alleviate sleep disorders since ancient times. In modern pharmacological research, JTW has been adopted for treating diabetes mellitus and even exerts antidepressant effects. However, the potential mechanisms deserve further elucidation.

AIM OF THE STUDY

The prevalence of diabetes mellitus combined with depressive disorder (DD) is continuing to increase, yet it is currently under-recognized and its treatment remains inadequate. The present study aims to explore the underlying therapeutics and mechanisms of JTW on DD.

MATERIALS AND METHODS

Chronic restraint stress was used on db/db mice to construct a mouse model of DD. The therapeutic effects of JTW were assessed by glucolipid metabolic indexes, behavioral tests, and depression-related neurotransmitter levels. The inflammatory status and cell apoptosis of different mice were investigated and the changes in the cAMP/PKA/CREB pathway were detected. Combining the results of fingerprinting with molecular docking, the active components of JTW were screened. A cellular model was constructed by intervention of glucose combined with corticosterone (CORT). The levels of apoptosis and depression-related neurotransmitters in HT-22 cells were examined, and the changes in the cAMP/PKA/CREB pathway were tested. Finally, the activator and inhibitor of the PKA protein were used for reverse validation experiments.

RESULTS

JTW could improve the impaired glucose tolerance, lipid metabolism disorders, and depression-like symptoms in DD mice. Meanwhile, JTW could alleviate the inflammatory status, suppress the microglia activation, and improve hippocampal neuron apoptosis in DD mice. The dual effects of JTW might be associated with the activation of the cAMP/PKA/CREB pathway. Berberine (Ber) was identified for the in vitro experiment, it could reverse the apoptosis of HT-22 cells and up-regulate the depression-related neurotransmitter levels, and the effects of Ber were related to the activation of the cAMP/PKA/CREB pathway as well.

CONCLUSION

JTW could exert both hypoglycemic and antidepressant effects through activating the cAMP/PKA/CREB signaling pathway, its active component, Ber, could improve the damage to HT-22 cells induced by glucose combined with CORT via the activation of the cAMP/PKA/CREB pathway. Ber may be one of the effective components of the dual effects of JTW.

Association of psychological distress and DNA methylation: A 5-year longitudinal population-based twin study

AIM

To identify the psychological distress (PD)-associated 5'-cytosine-phosphate-guanine-3' sites (CpGs), and investigate the temporal relationship between dynamic changes in DNA methylation (DNAm) and PD.

METHODS

This study included 1084 twins from the Chinese National Twin Register (CNTR). The CNTR conducted epidemiological investigations and blood withdrawal twice in 2013 and 2018. These included twins were used to perform epigenome-wide association studies (EWASs) and to validate the previously reported PD-associated CpGs selected from previous EWASs in PubMed, Embase, and the EWAS catalog. Next, a cross-lagged study was performed to examine the temporality between changes in DNAm and PD in 308 twins who completed both 2013 and 2018 surveys.

RESULTS

The EWAS analysis of our study identified 25 CpGs. In the validation analysis, 741 CpGs from 29 previous EWASs on PD were selected for validation, and 101 CpGs were validated to be significant at a false discovery rate <0.05. The cross-lagged analysis found a unidirectional path from PD to DNAm at 14 CpGs, while no sites showed significance from DNAm to PD.

CONCLUSIONS

This study identified and validated PD-related CpGs in a Chinese twin population, and suggested that PD may be the cause of changes in DNAm over time. The findings provide new insights into the molecular mechanisms underlying PD pathophysiology.

Berberine exerts antidepressant effects in vivo and in vitro through the PI3K/AKT/CREB/BDNF signaling pathway

BACKGROUND

Depression, a global neuropsychiatric disorder, brings a serious burden to patients and society as its incidence continues to rise. Berberine is one of the main compounds of a variety of Chinese herbal medicines and has been shown to have multiple pharmacological effects. However, whether berberine can exert antidepressant effects in vivo and in vitro and its related mechanisms remain to be explored.

METHODS

The chronic restraint stress (CRS) method and corticosterone (CORT) were applied to simulate depression-like behavior in vivo and neuronal apoptosis in vitro, respectively. The antidepressant effects of berberine were evaluated by behavioral tests and changes in the content of monoamine neurotransmitters. Inflammatory cytokines were detected and immunofluorescence staining was used to observe the expression levels of apoptosis-related proteins. RT-qPCR and Western blot were used to examine the mRNA and protein expression (or phosphorylation) levels of biomarkers of the PI3K/AKT/CREB/BDNF signaling pathways.

RESULTS

Behavioral tests and levels of neurotransmitters proved that berberine could effectively ameliorate depression-like symptoms in CRS mice. Meanwhile, the results of ELISA and immunofluorescence staining showed that berberine could alleviate inflammatory status and reduce cell apoptosis in vivo and in vitro. Moreover, the changes of the PI3K/AKT/CREB/BDNF signaling pathway induced by CRS or CORT in mouse hippocampus or HT-22 cells were significantly reversed by berberine.

CONCLUSION

Our current study suggested that berberine could exert antidepressant effects in vitro and in vivo, which may be associated with the PI3K/AKT/CREB/BDNF signaling pathway.

Caspase-1 affects chronic restraint stress-induced depression-like behaviors by modifying GABAergic dysfunction in the hippocampus

Major depression disorder (MDD) is one of the most common psychiatric disorders and one of the leading causes of disability in worldwide. Both inflammation and GABAergic dysfunction have been implicated in the pathophysiology of MDD. Caspase-1, a classic inflammatory caspase, regulates AMPARs-mediated glutamatergic neurotransmission. However, the role of caspase-1 in chronic stress-induced GABAergic dysfunction remains largely unknown. In this study, we found that serum and hippocampal caspase-1-IL-1β levels increased significantly in chronic restraint stress (CRS) mice, and a significant negative correlation occurred between levels of caspase-1 and depression-like behaviors. Furthermore, CRS significantly decreased GAD67 mRNA levels and GABAergic neurotransmission accompanied by the reduction of GABA concentration, reduced the amplitude and frequency of mIPSCs inhibitory postsynaptic currents (mIPSCs) and the decreased surface expression of GABA_ARs γ2 subunit in the hippocampus. Genetic deficiency of caspase-1 not only blocked CRS-induced depression-like behaviors, but also alleviated CRS-induced impairments in GABAergic neurotransmission. Finally, reexpression of caspase-1 in the hippocampus of Caspase-1^-/- mice increased susceptibility to stress-induced anxiety- and depression-like behaviors through inhibiting GAD67 expression and GABA_ARs-mediated synaptic transmission. Our study suggests that CRS dysregulates GABAergic neurotransmission via increasing the levels of caspase-1-mediated neuroinflammation in the hippocampus, ultimately leading to depression-like behaviors. This work illustrates that targeting caspase-1 may provide potential therapeutic benefits to stress-related GABAergic dysfunction in the pathogenesis of MDD.

DNA Tetrahedra-Based Delivery of MicroRNA-22 to Reduce Depressive Symptoms in Mice

Major depressive disorder (MDD) is a common illness with an increasing lifetime prevalence. Thus, an increasing number of studies have investigated the association between MDD and microRNAs (miRNAs), which are a novel approach for treating depression. However, the therapeutic potential of miRNA-based strategies has several limitations. To overcome these limitations, DNA tetrahedra (TDNs) have been used as piggyback materials. In this study, we successfully used TDNs as carriers of miRNA-22-3p (miR-22-3p) and synthesized a novel DNA nanocomplex (TDN-miR-22-3p), which was used in a lipopolysaccharide (LPS)-induced depression cell model. The results suggest that miR-22-3p may regulate inflammation by regulating phosphatase and tensin homologue (PTEN), an important regulatory molecule in the PI3K/AKT pathway, and downregulating the expression of NLRP3. We further validated the role of TDN-miR-22-3p in vivo using an LPS-induced animal model of depression. The results indicate that it ameliorated depression-like behavior and attenuated the expression of inflammation-related factors in mice. This study demonstrates the establishment of a straightforward and efficacious miRNA delivery system and the potential of TDNs as therapeutic vectors and tools for mechanistic studies. To the best of our knowledge, this is the first study to use TDNs in combination with miRNAs to treat depression.

Research Progress on the Pharmacodynamic Mechanisms of Sini Powder against Depression from the Perspective of the Central Nervous System

Depression is a highly prevalent emotional disorder characterized by persistent low mood, diminished interest, and loss of pleasure. The pathological causes of depression are associated with neuronal atrophy, synaptic loss, and neurotransmitter activity decline in the central nervous system (CNS) resulting from injuries, such as inflammatory responses. In Traditional Chinese Medicine (TCM) theory, patients with depression often exhibit the liver qi stagnation syndrome type. Sini Powder (SNP) is a classic prescription for treating such depression-related syndrome types in China. This study systematically summarized clinical applications and experimental studies of SNP for treatments of depression. We scrutinized the active components of SNP with blood-brain barrier (BBB) permeability and speculated about the corresponding pharmacodynamic pathways relevant to depression treatment through intervening in the CNS. Therefore, this article can enhance our understanding of SNP's pharmacological mechanisms and formula construction for depression treatment. Moreover, a re-demonstration of this classic TCM prescription in the modern-science language is of great significance for future drug development and research.

Suppressive Effects of Lactobacillus on Depression through Regulating the Gut Microbiota and Metabolites in C57BL/6J Mice Induced by Ampicillin

Depression is a medical and social problem. Multiple metabolites and neuroinflammation regulate it. Modifying the gut microbiota with probiotics to reduce depression through the gut-brain axis is a potential treatment strategy. In this study, three anti-depressive potentials of Lactobacillus spp. (LAB), including L. rhamnosus GMNL-74, L. acidophilus GMNL-185 and L. plantarum GMNL-141, which combined to produce low dosage LAB (1.6 × 108 CFU/mouse, LABL) and high dosage LAB (4.8 × 108 CFU/mouse, LABH), were administered to C57BL/6 mice induced depression by ampicillin (Amp). A behavioral test of depression, 16S ribosomal RNA gene amplicon sequencing, bioinformatic analysis, and short-chain fatty acid (SCFA) content measurement were executed to investigate the gut microbiota composition, activation of nutrient metabolism pathways, levels of inflammatory factors, gut-derived 5-HT biosynthesis genes, and SCFA levels in C57BL/6 mice. Results showed that after mice were induced by Amp, both LAB groups recovered from depressive behaviors, decreased the abundance of Firmicutes, and increased the abundance of Actinobacteria and Bacteroidetes in the mouse ileum. The prediction of metabolism pathways of microbes revealed the activation of arginine and proline metabolism, cyanoamino acid metabolism, and nicotinate and nicotinamide metabolism were increased, and fatty acid synthesis was decreased in both LAB groups. The LABH groups showed increased levels of acetic acid, propanoic acid, and iso-butyric acid and decreased butyric acid levels in the cecum. LABH treatment increased claudin-5 and reduced IL-6 mRNA expression. Both LAB groups also reduced monoamine oxidase, and the LABH group increased vascular endothelial growth factor mRNA expression. These results showed that the composite of three LAB exerts antidepressant effects by regulating the gut microbiota and modifying the levels of depression-related metabolites in C57BL/6J Amp-treated mice.

Effects of (S)-ketamine on depression-like behaviors in a chronic variable stress model: a role of brain lipidome

Introduction: Compelling evidence indicates that a single sub-anesthetic dose of (S)-ketamine elicits rapid and robust antidepressant effects. However, the underlying mechanisms behind the antidepressant effects of (S)-ketamine remain unclear. Methods: Here, using a chronic variable stress (CVS) model in mice, we analyzed changes inthe lipid compositions of the hippocampus and prefrontal cortex (PFC) with a mass spectrometry-based lipidomic approach. Results: Similar to previous research outcomes, the current study also showed that (S)-ketamine reversed depressive-like behaviors in mice produced by CVS procedures. Moreover, CVS induced changes inthe lipid compositions of the hippocampus and PFC, notably in the contents of sphingolipids, glycerolipids, and fatty acyls. With the administration of (S)-ketamine, CVS-induced lipid disturbances were partially normalized, particularly in the hippocampus. Conclusion: Altogether, our results indicated that (S)-ketamine could rescue CVS-induced depressive-like behaviors in mice through region-specific modulation of the brain lipidome, contributing to the understanding of (S)-ketamine's antidepressant effects.

Negative air ion exposure ameliorates depression-like behaviors induced by chronic mild stress in mice

The presence of negative air ions (NAI) is suggested to be a beneficial factor in improving psychological status and used in treating depression as an alternative approach. However, more biological evidence from animal models is needed to ensure the effects of NAI on the mood regulation, through which can facilitate identification of possible underlying mechanisms. In this study, the chronic mild stress (CMS) protocol was used to induce depressive-like behaviors in mice, and the effects of NAI exposure on CMS-induced depression-like behaviors were examined. Thirty-day NAI exposure prevented the CMS-induced depression-like behaviors as shown by the restoration of sucrose preference and reduced immobility time in the tail suspension test. In addition, the elevation of serous corticosterone was present in CMS-treated mice but not existed in those with the NAI exposure. Furthermore, we observed altered ratios of some cytokines secreted by type 1 T helper (Th1) cells and Th2 cells in CMS-treated mice, but it could be restored after NAI exposure. In conclusion, NAI intervention is able to ameliorate CMS-induced depression-like behaviors in mice, and this effect is associated with the alteration of corticosterone and functional rebalance between Th1 and Th2 cells.

Traditional herbal formula Jiao-tai-wan improves chronic restrain stress-induced depression-like behaviors in mice

OBJECTIVES

Jiao-tai-wan (JTW) has been often used to treat insomnia and diabetes mellitus. Recent studies found its antidepressant activity, but the related mechanism is not clear. This study is to evaluate the therapeutic effects of JTW on chronic restraint stress (CRS)-induced depression mice and explore the potential mechanisms.

METHODS

CRS was used to set up a depression model. Mice in different groups were treated with 0.9 % saline, JTW and fluoxetine. After the last day of CRS, the behavioral tests were conducted. The levels of neurotransmitters, inflammatory cytokines and HPA axis index were detected and the protein expressions of NLRP3 inflammasome complex were determined. H&E, NISSL, TUNEL and immunofluorescence staining were used to observe histopathological changes and the activation of microglia and astrocytes. The potential mechanisms were explored via network pharmacology and verified by Western blot.

RESULTS

The assessment of liver and kidney function showed that JTW was non-toxic. Behavioral tests proved that JTW can effectively ameliorate depression-like symptoms in CRS mice, which may be related to the inhibition of NLRP3 inflammasome activation. JTW can also improve the inflammatory state and HPA axis hyperactivity in mice, and has a protective effect on CRS-induced hippocampal neurons damage. The network pharmacology analysis and the results of Western blot suggested that the antidepressant effects of JTW may be related to the MAPK signaling pathway.

CONCLUSION

Our findings indicated that JTW may exert antidepressant effects in CRS-induced mice by inhibiting NLRP3 inflammasome activation and improving inflammatory state, and MAPK signaling pathway may also be involved.

Identification of Potential Diagnoses Based on Immune Infiltration and Autophagy Characteristics in Major Depressive Disorder

Background: Major depressive disorder (MDD) is a serious mental illness characterized by mood changes and high suicide rates. However, no studies are available to support a blood test method for MDD diagnosis. The objective of this research was to identify potential peripheral blood biomarkers for MDD and characterize the novel pathophysiology.

Methods: We accessed whole blood microarray sequencing data for MDD and control samples from public databases. Biological functions were analysed by GO and KEGG pathway enrichment analyses using the clusterprofile R package. Infiltrated immune cell (IIC) proportions were identified using the CIBERSORT algorithm. Clustering was performed using the ConsensusClusterPlus R package. Protein–protein interactions (PPI) were assessed by constructing a PPI network using STRING and visualized using Cytoscape software. Rats were exposed to chronic unpredictable mild stress (CUMS) for 6 weeks to induce stress behaviour. Stress behaviour was evaluated by open field experiments and forced swimming tests. Flow cytometry was used to analyse the proportion of CD8⁺ T cells. The expression of the corresponding key genes was detected by qRT–PCR.

Results: We divided MDD patients into CD8H and CD8L clusters. The functional enrichment of marker genes in the CD8H cluster indicated that autophagy-related terms and pathways were significantly enriched. Furthermore, we obtained 110 autophagy-related marker genes (ARMGs) in the CD8H cluster through intersection analysis. GO and KEGG analyses further showed that these ARMGs may regulate a variety of autophagy processes and be involved in the onset and advancement of MDD. Finally, 10 key ARMGs were identified through PPI analysis: RAB1A, GNAI3, VAMP7, RAB33B, MYC, LAMP2, RAB11A, HIF1A, KIF5B, and PTEN. In the CUMS model, flow cytometric analysis confirmed the above findings. qRT–PCR revealed significant decreases in the mRNA levels of Gnai3, Rab33b, Lamp2, and Kif5b in the CUMS groups.

Conclusion: In this study, MDD was divided into two subtypes. We combined immune infiltrating CD8⁺ T cells with autophagy-related genes and screened a total of 10 ARMG genes. In particular, RAB1A, GNAI3, RAB33B, LAMP2, and KIF5B were first reported in MDD. These genes may offer new hope for the clinical diagnosis of MDD.

Deletion of Schizophrenia Susceptibility Gene Ulk4 Leads to Abnormal Cognitive Behaviors via Akt-GSK-3 Signaling Pathway in Mice

OBJECTIVES

Despite of strenuous research in the past decades, the etiology of schizophrenia (SCZ) still remains incredibly controversial. Previous genetic analysis has uncovered a close association of Unc-51 like kinase 4 (ULK4), a family member of Unc-51-like serine/threonine kinase, with SCZ. However, animal behavior data which may connect Ulk4 deficiency with psychiatric disorders, particularly SCZ are still missing.

METHODS

We generated Emx1-Cre:Ulk4flox/flox conditional knockout (CKO) mice, in which Ulk4 was deleted in the excitatory neurons of cerebral cortex and hippocampus.

RESULTS

The cerebral cellular architecture was maintained but the spine density of pyramidal neurons was reduced in Ulk4 CKO mice. CKO mice showed deficits in the spatial and working memories and sensorimotor gating. Levels of p-Akt and p-GSK-3α/β were markedly reduced in the CKO mice indicating an elevation of GSK-3 signaling. Mechanistically, Ulk4 may regulate the GSK-3 signaling via putative protein complex comprising of two phosphatases, protein phosphatase 2A (PP2A) and 1α (PP1α). Indeed, the reduction of p-Akt and p-GSK-3α/β was rescued by administration of inhibitor acting on PP2A and PP1α in CKO mice.

CONCLUSIONS

Our data identified potential downstream signaling pathway of Ulk4, which plays important roles in the cognitive functions and when defective, may promote SCZ-like pathogenesis and behavioral phenotypes in mice.

The role of PTEN in primary sensory neurons in processing itch and thermal information in mice

PTEN is known as a tumor suppressor and plays essential roles in brain development. Here, we report that PTEN in primary sensory neurons is involved in processing itch and thermal information in adult mice. Deletion of PTEN in the dorsal root ganglia (DRG) is achieved in adult Drg11-Cre^ER: PTEN^flox/flox (PTEN CKO) mice with oral administration of tamoxifen, and CKO mice develop pathological itch and elevated itch responses on exposure to various pruritogens. PTEN deletion leads to ectopic expression of TRPV1 and MrgprA3 in IB4⁺ non-peptidergic DRG neurons, and the TRPV1 is responsive to capsaicin. Importantly, the elevated itch responses are no longer present in Drg11-Cre^ER: PTEN^flox/flox: TRPV1^flox/flox (PTEN: TRPV1 dCKO) mice. In addition, thermal stimulation is enhanced in PTEN CKO mice but blunted in dCKO mice. PTEN-involved regulation of itch-related gene expression in DRG neurons provides insights for understanding molecular mechanism of itch and thermal sensation at the spinal level.

Validity of chronic restraint stress for modeling anhedonic-like behavior in rodents: a systematic review and meta-analysis

BACKGROUND

Chronic restraint stress (CRS) is widely used to recapitulate depression phenotypes in rodents but is frequently criticized for a perceived lack of efficacy. The aim of this study was to evaluate anhedonic-like behavior in the CRS model in rodents by performing a meta-analysis of studies that included sucrose preference tests.

METHODS

This meta-analysis was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations. We comprehensively searched for eligible studies published before June 2021 in the PubMed, Embase, Medline, and Web of Science databases. We chose sucrose preference ratio as the indicative measure of anhedonia because it is a core symptom of depression in humans.

RESULTS

Our pooled analysis included 34 articles with 57 studies and seven rodent species/strains and demonstrated decreased sucrose preference in the stress group compared with controls. The duration of CRS differentially affected the validity of anhedonic-like behavior in the models. Rats exhibited greater susceptibility to restraint stress than mice, demonstrating inter-species variability.

CONCLUSIONS

Our meta-analysis of studies that used the CRS paradigm to evaluate anhedonic-like behavior in rodents was focused on a core symptom of depression (anhedonia) as the main endpoint of the model and identified species-dependent susceptibility to restraint stress.

Chronic restraint stress produces sex-specific behavioral and molecular outcomes in the dorsal and ventral rat hippocampus

Stress-related disorders display differences at multiple levels according to sex. While most studies have been conducted in male rodents, less is known about comparable outcomes in females. In this study, we found that the chronic restraint stress model (2.5 h/day for 14 days) triggers different somatic responses in male and female adult rats. Chronic restraint produced a loss in sucrose preference and novel location preference in male rats. However, chronic restraint failed to produce loss of sucrose preference in females, while it improved spatial performance. We then characterized the molecular responses associated with these behaviors in the hippocampus, comparing the dorsal and ventral poles. Notably, sex- and hippocampal pole-specific transcriptional signatures were observed, along with a significant concordance between the female ventral and male dorsal profiles. Functional enrichment analysis revealed both shared and specific terms associated with each pole and sex. By looking into signaling pathways that were associated with these terms, we found an ample array of sex differences in the dorsal and, to a lesser extent, in the ventral hippocampus. These differences were mainly present in synaptic TrkB signaling, Akt pathway, and glutamatergic receptors. Unexpectedly, the effects of stress on these pathways were rather minimal and mostly dissociated from the sex-specific behavioral outcomes. Our study suggests that female rats are resilient and males susceptible to the restraint stress exposure in the sucrose preference and object location tests, while the activity of canonical signaling pathways is primarily determined by sex rather than stress in the dorsal and ventral hippocampus.

Genetic association between major depressive disorder and type 2 diabetes mellitus: Shared pathways and protein networks

BACKGROUND

Major depressive disorder (MDD) and type 2 diabetes mellitus (T2DM) are common public health disorders that often co-occur. This study aims to determine whether gene expression profiles from individuals with MDD or T2DM overlap and if there are any functional interconnectivity between identified genes using protein-protein interaction (PPI).

METHODS

The DNA microarray datasets were extracted from the Gene Expression Omnibus. Gene expression dataset GSE98793 from a case-control study of MDD (64 healthy control subjects, 128 patients) and dataset GSE15653 from a case-control study of T2DM (nine controls, nine individuals with T2DM) were used for this secondary and post-hoc analysis. GO enrichment analyses and Reactome pathway enrichment analysis were performed for functional enrichment analyses with the shared genes. PPI networks, PPI clusters and hub genes were performed to detect the potential relationships among differentially expressed genes (DEG) -encoding proteins in both MDD and T2DM.

RESULTS

A total of 3640 DEGs were identified in the MDD group when compared to the control group, whereas 3700 DEGs were identified in the T2DM group when compared to the control groups, among which 244 DEGs were overlap genes. The identified DEGs were enriched for Interleukin-4 and Interleukin-13 signaling, neutrophil degranulation, as well as other select species of the innate immune system. The biological processes of neurofibrillary tangle assembly regulation, tau-protein kinase activity regulation, amyloid-beta clearance regulation, amyloid-beta formation regulation and neuron apoptotic processes were also identified. Molecular function analysis indicated that identified genes were mainly enriched for amyloid-beta binding. 925 out of 1006 protein-protein interactions and six sub-networks were identified reflecting the disparate biological domains of overlapping genes. Ten hub genes further highlight the putative importance of tau-protein kinase activity, inflammatory response and neuron apoptotic regulatory processes across MDD and T2DM.

CONCLUSIONS

Our results indicate that an overlapping genetic architecture subserves MDD and T2DM. Genes relevant to the innate immune system, tau protein formation, and cellular aging were identified. Results indicate that the common, often comorbid, conditions of MDD and T2DM have a pathoetiologic nexus.

Adjunctive Nonconvulsive Electrotherapy for Patients with Depression: a Systematic Review

The efficacy and safety of adjunctive nonconvulsive electrotherapy (NET) for patients with depression are undetermined. This systematic review was conducted to examine the efficacy and safety of adjunctive NET for patients with depression. Chinese (WanFang and Chinese Journal Net) and English (PubMed, EMBASE, PsycINFO and the Cochrane Library) databases were systematically searched from their inception until Jan 27, 2021 by three independent investigators. One randomized controlled trial (RCT) with 3 treatment arms (n = 108) and two observational studies (single-group, before-after design, n = 31) were included. In the RCT, the antidepressant efficacy of NET on depression was similar to that of electroconvulsive therapy (ECT) (P > 0.05) but with significantly fewer neurocognitive impairments as measured by the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) (P < 0.05). In two observational studies, the 17-item Hamilton Depression Rating Scale (HAMD-17) scores decreased significantly from baseline to post-NET (all Ps < 0.05), without adverse neurocognitive effects. In the RCT, adverse drug reactions (ADRs) were not separately reported among the 3 treatment arms but a similar rate of discontinuation was reported. The currently available limited evidence from 3 studies suggests that NET as an adjunctive treatment may be a safe, well-tolerated, effective therapy for depression without serious neurocognitive impairments.