The glucocorticoid receptor: pivot of depression and of antidepressant treatment?

Depressive-Like Effects of Foreclosing: A Cross-Sectional Study of Hair Cortisol Concentration

INTRODUCTION

Foreclosing and home eviction have been associated with various negative health outcomes, probably due to exposure to such stressful circumstance, but there is no evidence about foreclosure and home eviction to elicit cortisol responses.

METHODS

Participants who recently had received a court eviction notice were compared to subjects suffering a depressive disorder and to healthy controls in terms of hair cortisol concentrations.

RESULTS

Subjects under the stressful circumstance of foreclosure and patients with depression showed comparable concentrations in most of the hair segments while healthy subjects displayed the lowest levels of cortisol.

CONCLUSION

The findings show that foreclosure and home eviction are associated with increased cumulative hair cortisol and with depressive-like symptoms. Foreclosing procedures yielded to maintain high levels of cortisol which may increase the risk to develop major depression.

The Role of Pharmacogenetics in Personalizing the Antidepressant and Anxiolytic Therapy

Pharmacotherapy for neuropsychiatric disorders, such as anxiety and depression, has been characterized by significant inter-individual variability in drug response and the development of side effects. Pharmacogenetics, as a key part of personalized medicine, aims to optimize therapy according to a patient's individual genetic signature by targeting genetic variations involved in pharmacokinetic or pharmacodynamic processes. Pharmacokinetic variability refers to variations in a drug's absorption, distribution, metabolism, and elimination, whereas pharmacodynamic variability results from variable interactions of an active drug with its target molecules. Pharmacogenetic research on depression and anxiety has focused on genetic polymorphisms affecting metabolizing cytochrome P450 (CYP) and uridine 5'-diphospho-glucuronosyltransferase (UGT) enzymes, P-glycoprotein ATP-binding cassette (ABC) transporters, and monoamine and γ-aminobutyric acid (GABA) metabolic enzymes, transporters, and receptors. Recent pharmacogenetic studies have revealed that more efficient and safer treatments with antidepressants and anxiolytics could be achieved through genotype-guided decisions. However, because pharmacogenetics cannot explain all observed heritable variations in drug response, an emerging field of pharmacoepigenetics investigates how epigenetic mechanisms, which modify gene expression without altering the genetic code, might influence individual responses to drugs. By understanding the epi(genetic) variability of a patient's response to pharmacotherapy, clinicians could select more effective drugs while minimizing the likelihood of adverse reactions and therefore improve the quality of treatment.

Intestinal permeability and its significance in psychiatric disorders - a narrative review and future perspectives

The topic of increased intestinal permeability and its impact on the human body is. increasingly being addressed by researchers. It is associated with disruption of the. intestinal barrier, leading to the "leaky gut" syndrome. This can be assessed by. classical methods, determining the concentration of orally administered tracer. molecules in urine or by using biomarkers such as LPS, LBP or zonulin in blood. plasma. The presence of bacterial endotoxins in the body causes inflammation. In this. article, we review research on increased intestinal permeability in psychiatric illness. mood disorders, schizophrenia, alcohol dependence, anxiety disorders,. neurodegenerative and neurodevelopmental disorders. The results of the studies used. to assess intestinal permeability in different disease entities are presented. Possible. mechanisms for these interactions are the effects of chronic, low-grade inflammation. on the human brain, causing interruption of the brain blood barrier and dysfunction of. astrocytes and microglia. This affects brain function by reducing the number of. dopaminergic neurons, disrupting tryptophan metabolism and altering the amount of. GABA and glutamate. The links and mechanisms found may, in the future, allow earlier. detection of diseases and their targeted treatment.

Diet and depression: A systematic review of whole dietary interventions as treatment in patients with depression

BACKGROUND & RATIONALE

Depression is a common mental illness that afflicts over 300 million individuals worldwide. Despite a variety of therapeutic options available, a significant number of depressed patients fail to respond to treatment. Current guidelines for treating depression suggest that supplementation of essential nutrients may be an appropriate adjunctive to treatment, but research investigating full dietary interventions for depressed patients is scarce.

STUDY OBJECTIVE

The primary aim of this study was to systematically review published scientific literature investigating full dietary interventions as treatment for individuals with a diagnosis of depression. In doing so, we assessed existing evidence for recommendation of a dietary intervention and reviewed theory of how diet may be important in this context.

METHODS

A systematic search was conducted using OVID to search Medline, PsychINFO, and EMBASE, and PubMed for relevant publications. Only studies including full dietary interventions for patients with Major Depressive Episode, Major Depressive Disorder, Persistent Depressive Disorder, Seasonal Affective Disorder, or Dysthymia, as diagnosed using criteria defined in the chapter of "Depressive Disorders" in the DSM, were included.

RESULTS

Only five studies met the inclusion criteria for this review. All five studies included in this review reported improvements in mood following dietary intervention as compared to the comparison group. However, heterogeneity in both the dietary intervention and the outcome(s) measured made it difficult to compare these studies against each other and to generalize them to larger populations.

CONCLUSION

The findings of this review provide preliminary evidence for the positive impact of dietary interventions in the treatment of depressed patients. However, the mechanism by which particular diets induce positive changes in mood, be it through anti-inflammatory mechanisms or via weight loss in overweight patients, is unclear. Future research investigating the impact of dietary interventions on a large-scale is warranted and needed.

Adaptogenic property of Asparagus racemosus: Future trends and prospects

Major depressive disorder (MDD) is a multimodal neuropsychiatric and neurodegenerative illness characterized by anhedonia, continued melancholy, dysfunctional circadian rhythm and many other behavioral infirmities. Depression is also associated with somatic ailments such as cardiometabolic diseases. The existing and upcoming hypotheses have succeeded in explaining the pathophysiology of depression. Only a few of the most validated theories, such as hyperactivity of the HPA axis, activated inflammatory-immune response, and monoaminergic and GABAergic deficit hypotheses, have been discussed in this review. So, an effective and safer alternative approach beyond symptomatic relief has been desired. Therefore, botanical products have steadily been probed to strengthen the modern medicinal system as a promising medicament. In this line, Asparagus racemosus Willd. belongs to Asparagaceace family is the well-documented adaptogen cited in the ancient texts namely, Ayurvedic, Greek, and Chinese medicine system. The whole plant possesses pleiotropic therapeutic activity, antioxidant, anti-inflammatory, immunomodulatory, neuroprotective, nootropic, antidepressant, etc., without showing any remarkable side effects. The literature review has also suggested that A. racemosus administration at varied levels alleviates depression by modulating the HPA axis, increasing BDNF levels, and monoaminergic and GABAergic neurotransmission. Alongside, spikes the level of antioxidant enzymes, SOD, GSH peroxidase, GSH, and catalase in distinct brain regions (i.e., hippocampus, prefrontal cortex, amygdala, and hypothalamus) and promote neurogenesis and neuroplasticity. Thus, it could be a new generation antidepressant that provides relief from both behavioral and somatic illness. The review first describes the plant characteristics, then discusses the hypotheses associated with the pathogenesis of depression, and gives an insight into A. racemosus antidepressant properties and the underlying mechanism.

Human myeloid progenitor glucocorticoid receptor activation causes genomic instability, type 1 IFN- response pathway activation and senescence in differentiated microglia; an early life stress model

One form of early life stress, prenatal exposure to glucocorticoids (GCs), confers a higher risk of psychiatric and neurodevelopmental disorders in later life. Increasingly, the importance of microglia in these disorders is recognized. Studies on GCs exposure during microglial development have been limited, and there are few, if any, human studies. We established an in vitro model of ELS by continuous pre-exposure of human iPS-microglia to GCs during primitive hematopoiesis (the critical stage of iPS-microglial differentiation) and then examined how this exposure affected the microglial phenotype as they differentiated and matured to microglia, using RNA-seq analyses and functional assays. The iPS-microglia predominantly expressed glucocorticoid receptors over mineralocorticoid receptors, and in particular, the GR-α splice variant. Chronic GCs exposure during primitive hematopoiesis was able to recapitulate in vivo ELS effects. Thus, pre-exposure to prolonged GCs resulted in increased type I interferon signaling, the presence of Cyclic GMP-AMP synthase-positive (cGAS) micronuclei, cellular senescence and reduced proliferation in the matured iPS-microglia. The findings from this in vitro ELS model have ramifications for the responses of microglia in the pathogenesis of GC- mediated ELS-associated disorders such as schizophrenia, attention-deficit hyperactivity disorder and autism spectrum disorder.

Mechanisms of Maternal Diet-Induced Obesity Affecting the Offspring Brain and Development of Affective Disorders

Depression and metabolic disease are common disorders that share a bidirectional relationship and continue to increase in prevalence. Maternal diet and maternal behaviour both profoundly influence the developmental trajectory of offspring during the perinatal period. At an epidemiological level, both maternal depression and obesity during pregnancy have been shown to increase the risk of neuropsychiatric disease in the subsequent generation. Considerable progress has been made to understand the mechanisms by which maternal obesity disrupts the developing offspring gut-brain axis, priming offspring for the development of affective disorders. This review outlines such mechanisms in detail, including altered maternal care, the maternal microbiome, inflammation, breast milk composition, and maternal and placental metabolites. Subsequently, offspring may be prone to developing gut-brain interaction disorders with concomitant changes to brain energy metabolism, neurotransmission, and behaviour, alongside gut dysbiosis. The gut microbiome may act as a key modifiable, and therefore treatable, feature of the relationship between maternal obesity and the offspring brain function. Further studies examining the relationship between maternal nutrition, the maternal microbiome and metabolites, and offspring neurodevelopment are warranted to identify novel therapeutic targets.

The role of astrocytes in behaviors related to emotion and motivation

Astrocytes are present throughout the brain and intimately interact with neurons and blood vessels. Three decades of research have shown that astrocytes reciprocally communicate with neurons and other non-neuronal cells in the brain and dynamically regulate cell function. Astrocytes express numerous receptors for neurotransmitters, neuromodulators, and cytokines and receive information from neurons, other astrocytes, and other non-neuronal cells. Among those receptors, the main focus has been G-protein coupled receptors. Activation of G-protein coupled receptors leads to dramatic changes in intracellular signaling (Ca²⁺ and cAMP), which is considered a form of astrocyte activity. Methodological improvements in measurement and manipulation of astrocytes have advanced our understanding of the role of astrocytes in circuits and have begun to reveal unexpected functions of astrocytes in behavior. Recent studies have suggested that astrocytic activity regulates behavior flexibility, such as coping strategies for stress exposure, and plays an important role in behaviors related to emotion and motivation. Preclinical evidence suggests that impairment of astrocytic function contributes to psychiatric diseases, especially major depression. Here, we review recent progress on the role of astrocytes in behaviors related to emotion and motivation.

A viewpoint on aldosterone and BMI related brain morphology in relation to treatment outcome in patients with major depression

An abundance of knowledge has been collected describing the involvement of neuroendocrine parameters in major depression. The hypothalamic-pituitary-adrenocortical (HPA) axis regulating cortisol release has been extensively studied; however, attempts to target the HPA axis pharmacologically to treat major depression have failed. This review focuses on the importance of the adrenocortical stress hormone aldosterone, which is released by adrenocorticotropic hormone and angiotensin, and the mineralocorticoid receptor (MR) in depression. Depressed patients, in particular those with atypical depression, have signs of central hyperactivation of the aldosterone sensitive MR, potentially as a consequence of a reactive aldosterone release induced by low blood pressure and as a result of low sensitivity of peripheral MR. This is reflected in reduced heart rate variability, increased salt appetite and sleep changes in this group of patients. In addition, enlarged brain ventricles, compressed corpus callosum and changes of the choroid plexus are associated with increased aldosterone (in relation to cortisol). Furthermore, subjects with these features often show obesity. These characteristics are related to a worse antidepressant treatment outcome. Alterations in choroid plexus function as a consequence of increased aldosterone levels, autonomic dysregulation, metabolic changes and/or inflammation may be involved. The characterization of this regulatory system is in its early days but may identify new targets for therapeutic interventions.

Chronic stress is associated with reward and emotion-related eating behaviors in college students

Introduction

Stress is related to altered olfactory perception and eating behaviors. The current study investigated the association between chronic stress, food reward and perception of food and non-food odors among college students.

Methods

Sixty-one participants completed the Perceived Stress Scale (PSS) and the Brief Daily Stressors Screening Tool (BDSST). The detective threshold and suprathreshold perception (pleasantness, intensity, and familiarity) of two food (chocolate, strawberry) odors and a non-food (rose) odor were measured. Food reward and macronutrient preference were measured using the computerized Leeds Food Preference Questionnaire and the Macronutrient and Taste Preference Ranking task, respectively. Reward-related eating, emotional eating and eating-related inhibitory control were measured by the Dutch Eating Behavior Questionnaire (DEBQ) and the Reward-Based Eating Drive Scale (RED) scales.

Results

Neither the perceived stress or the severity of daily life stressor exposure was related to odor sensitivity, however, the PSS score was significantly correlated with pleasantness for strawberry odor (r = 0.329, p = 0.013). Chronic stress (PSS and BDSST scores) was significantly correlated with the DEBQ emotional eating and reward-related eating measured by RED (all ps < 0.01). Moreover, the BDSST score was negatively correlated with subjective liking for low-calorie sweet foods (r = -0.46, p < 0.001).

Discussion

Together, our preliminary results suggest disassociated effect of chronic stress on odor perception and eating behaviors.

Disturbed relationship between glucocorticoid receptor and 5-HT1AR/5-HT2AR in ADHD rats: A correlation study

Objective

This work is to investigate the alterations of the central 5-hydroxytryptamine (5-HT) system in spontaneously hypertensive rats (SHR) and the correlation with the behaviors of SHR, and to explore the effects of glucocorticoid intervention on the central 5-HT system and SHR behaviors.

Materials and methods

Three weeks old SHR were chosen as the attention-deficit hyperactivity disorder (ADHD) model and treated with glucocorticoid receptor (GR) agonist or inhibitor, whereas Wista Kyoto rats (WKY) were chosen as the normal control group. Open-field test and Làt maze test were used to evaluate the spontaneous activities and non-selective attention. The levels of 5-HT in the extracellular fluid specimens of the prefrontal cortex of rats were analyzed by high-performance liquid chromatography. The expressions of GR, 5-HT1A receptor (5-HT1AR), and 5-HT2A receptor (5-HT2AR) in the prefrontal cortex were analyzed through immunohistochemistry.

Results

Our study demonstrated that the 5-HT level was lower in the prefrontal cortex of SHR compared to that of WKY. The Open-field test and Làt maze test showed that GR agonist (dexamethasone, DEX) intervention ameliorated attention deficit and hyperactive behavior, whereas GR inhibitor (RU486) aggravated the disorders. With DEX, the expression levels of 5-HT and 5-HT2AR in the prefrontal cortex of SHR were significantly higher than those in the control group, whereas the expression level of 5-HT1AR was lower. However, the expression levels of 5-HT and 5-HT2AR were significantly decreased after the intervention with RU486, while the expression level of 5-HT1AR increased. Results showed that glucocorticoid was negatively correlated with 5-HT1AR and positively correlated with 5-HT2AR.

Conclusion

In the prefrontal cortex of ADHD rats, the down-regulation of 5-HT and 5-HT2AR expressions and the up-regulation of 5-HT1AR, compared with WYK rats, suggested a dysfunctional central 5-HT system in ADHD rats. The GR agonist can upregulate the expression of 5-HT and 5-HT2AR and downregulate the expression of 5-HT1AR in the prefrontal cortex of SHR as well as reduce the hyperactivity and attention deficit behavior in SHR, while the opposite was true for the GR inhibitor. It is suggested that the dysfunction of the 5-HT system in ADHD rats is closely related to glucocorticoid receptor activity.

The Effects of Prenatal Dexamethasone Exposure on Brain Metabolic Homeostasis in Adulthood: Implications for Depression

Since depression produces a long-term negative impact on quality of life, understanding the pathophysiological changes implicated in this disorder is urgent. There is growing evidence that demonstrates a key role for dysfunctional energy metabolism in driving the onset of depression; thus, bioenergetic alterations should be extensively studied. Brain metabolism is known to be a glucocorticoid-sensitive process, but the long-lasting consequences in adulthood following high levels of glucocorticoids at the early stages of life are unclear. We examined a possible association between brain energetic changes induced by synthetic glucocorticoid-dexamethasone treatment in the prenatal period and depressive-like behavior. The results show a reduction in the oxidative phosphorylation process, Krebs cycle impairment, and a weakening of the connection between the Krebs cycle and glycolysis in the frontal cortex of animals receiving dexamethasone, which leads to ATP reduction. These changes appear to be mainly due to decreased expression of pyruvate dehydrogenase, impairment of lactate transport to neurons, and pyruvate to the mitochondria. Acute stress in adulthood only slightly modified the observed alterations in the frontal cortex, while in the case of the hippocampus, prenatal exposure to dexamethasone made this structure more sensitive to future adverse factors.

Effect of citalopram and sertraline on the expression of miRNA- 124, 132, and 16 and their protein targets in patients with depression

OBJECTIVES

This study aimed to evaluate the effect of SSRIs on the expression of miRNAs and their protein targets.

MATERIALS AND METHODS

In a 100 day open-label study of citalopram (n=25) and sertraline (n=25), levels of miRNA 16, 132, and 124 and glucocorticoid receptor (GR), Brain-derived neurotrophic factor (BDNF), and serotonin transporter (SERT) protein expression were measured by QRT-PCR and western blot in healthy control (n=20), patients with depression at the baseline, and same patients after 100 days of treatment.

RESULTS

Expression levels of GR and BDNF proteins were lower in the depressed group before treatment as compared with the healthy group (P<0.0001). The SERT level was higher among the depressed group before treatment in comparison with the healthy group (P<0.0001). The level of GR and BDNF significantly increased, and SERT expression decreased after receiving sertraline (P<0.05). When the depressed group received citalopram, only SERT and GR were altered (P<0.05). Among the microRNAs' expression investigated, mir-124 and mir-132 were higher, and mir-16 was lower among the depressed compared with the healthy group (P<0.0001). Individuals receiving citalopram only showed an increase in the expression of mir-16 while administration of sertraline led to a significant increase in the expression of mir-16 and a decrease in mir-124 and mir-132 (P<0.05).

CONCLUSION

This elucidated the relationship between antidepressant treatment and the expression of different microRNA that control gene expression in various pathways involved in depressed patients. Receiving SSRI can affect the level of these proteins and their relevant microRNAs.

Fermented Perilla frutescens Ameliorates Depression-like Behavior in Sleep-Deprivation-Induced Stress Model

Excessive stress plays a critical role in the pathogenesis of mood disorders such as depression. Fermented natural products have recently attracted attention because of their health benefits. We evaluated the antidepressant-like efficacy of fermented Perilla frutescens (FPF), and its underlying mechanisms, in sleep deprivation (SD)-induced stress mice. SD-stressed mice revealed a remarkable increase in the immobility time in both forced swimming test and tail suspension test; this increase was ameliorated by treatment with FPF at doses of 100 and 150 mg/kg. FPF treatment also reduced the level of stress hormones such as corticosterone and adrenocorticotropic hormone. Additionally, FPF increased the levels of serotonin and dopamine which were significantly decreased in the brain tissues of SD-stressed mice. The increased expression of proinflammatory cytokines, such as TNF-α and IL1β, and the decreased expression of brain-derived neurotrophic factor (BDNF) in the stressed mice were significantly reversed by FPF treatment. Furthermore, FPF also increased phosphorylation of tropomyosin receptor kinase B (TrkB), extracellular regulated protein kinase (ERK), and cAMP response element binding protein (CREB). Among the six components isolated from FPF, protocatechuic acid and luteolin-7-O-glucuronide exhibited significant antidepressant-like effects, suggesting that they are major active components. These findings suggest that FPF has therapeutic potential for SD-induced stress, by correcting dysfunction of hypothalamic-pituitary-adrenal axis and modulating the BDNF/TrkB/ERK/CREB signaling pathway.

MAD2B Blunts Chronic Unpredictable Stress and Corticosterone Stimulation-Induced Depression-Like Behaviors in Mice

BACKGROUND

Depression is a prevalent and recurrent psychiatric disorder. Aberrant neural structure and activity play fundamental roles in the occurrence of depression. Mitotic arrest deficient protein (MAD2B) is highly expressed in neurons and may be implicated in synaptic plasticity in the central nervous system. However, the effect of MAD2B in depression, as well as the related molecular mechanism, is uncertain.

METHODS

Here, we employed mouse models of depression induced by chronic unpredictable stress exposure or corticosterone (CORT) stimulation. Depression-like behaviors in mice were evaluated by sucrose preference, forced swimming, and tail suspension tests. Hippocampal MAD2B overexpression was mediated by adeno-associated virus 8 containing enhanced green fluorescent protein. In vitro primary neuronal cells were obtained from the hippocampus of rat embryos and were treated with CORT, and MAD2B overexpression was performed using lentivirus. MAD2B and glutamate metabotropic receptor 4 (GRM4) levels were evaluated by western blots and quantitative PCR. Primary neuronal miR-29b-3p expression was detected by quantitative PCR.

RESULTS

MAD2B expression was reduced in the hippocampus in mice exhibiting depressive-like behaviors. However, hippocampal MAD2B overexpression protected mice from developing either chronic unpredictable stress- or CORT-induced depression-like behaviors, an effect associated with reduced expression of GRM4, a presynaptic receptor involved in depression. Moreover, MAD2B overexpression in primary neuronal cells also decreased GRM4 expression while enhancing the level of miR-29b-3p; this phenomenon was also observed under CORT stimulation.

CONCLUSIONS

Our results suggest an important role of neuronal MAD2B in the pathogenesis of depression via the miR-29b-3p/GRM4 signaling pathway. MAD2B could be a potential therapeutic target for depressive disorders.

Heterogeneity in major depressive disorder: The need for biomarker-based personalized treatments

Major Depressive Disorder (MDD) or depression is a pathological mental condition affecting millions of people worldwide. Identification of objective biological markers of depression can provide for a better diagnostic and intervention criteria; ultimately aiding to reduce its socioeconomic health burden. This review provides a comprehensive insight into the major biomarker candidates that have been implicated in depression neurobiology. The key biomarker categories are covered across all the "omics" levels. At the epigenomic level, DNA-methylation, non-coding RNA and histone-modifications have been discussed in relation to depression. The proteomics system shows great promise with inflammatory markers as well as growth factors and neurobiological alterations within the endocannabinoid system. Characteristic lipids implicated in depression together with the endocrine system are reviewed under the metabolomics section. The chapter also examines the novel biomarkers for depression that have been proposed by studies in the microbiome. Depression affects individuals differentially and explicit biomarkers identified by robust research criteria may pave the way for better diagnosis, intervention, treatment, and prediction of treatment response.

Innate lymphoid cells in depression: Current status and perspectives

The recent discovery of innate lymphoid cells (ILCs) has provided new insights into our understanding of the pathogenesis of many disease conditions with immune dysregulation. Type 1 innate lymphoid cells (ILC1s) induce type I immunity and are characterized by the expression of signature cytokine IFN-γ and the master transcription factor T-bet; ILC2s stimulate type II immune responses and are defined by the expression of signature cytokines IL-5 and IL-13, and transcription factors ROR-α and GATA3; ILC3s requires the transcription factor RORγt and produce IL-22 and IL-17. ILCs are largely tissue-resident and are enriched at barrier surfaces of the mammalian body. Increasing evidence shows that inflammation is involved in the pathogenesis of depression. Although few studies have directly investigated the role of ILCs in depression, several studies have examined the levels of cytokines produced by ILCs in depressed subjects. This review summarizes the potential roles of ILCs in depression. A better understanding of the biology of ILCs may lead to the development of new therapeutic strategies for the management of depression.

A Novel Model Using AAV9-Cre to Knockout Adult Leydig Cell Gene Expression Reveals a Physiological Role of Glucocorticoid Receptor Signalling in Leydig Cell Function

Glucocorticoids are steroids involved in key physiological processes such as development, metabolism, inflammatory and stress responses and are mostly used exogenously as medications to treat various inflammation-based conditions. They act via the glucocorticoid receptor (GR) expressed in most cells. Exogenous glucocorticoids can negatively impact the function of the Leydig cells in the testis, leading to decreased androgen production. However, endogenous glucocorticoids are produced by the adrenal and within the testis, but whether their action on GR in Leydig cells regulates steroidogenesis is unknown. This study aimed to define the role of endogenous GR signalling in adult Leydig cells. We developed and compared two models; an inducible Cre transgene driven by expression of the Cyp17a1 steroidogenic gene (Cyp17-iCre) that depletes GR during development and a viral vector-driven Cre (AAV9-Cre) to deplete GR in adulthood. The delivery of AAV9-Cre ablated GR in adult mouse Leydig cells depleted Leydig cell GR more efficiently than the Cyp17-iCre model. Importantly, adult depletion of GR in Leydig cells caused reduced expression of luteinising hormone receptor (Lhcgr) and of steroidogenic enzymes required for normal androgen production. These findings reveal that Leydig cell GR signalling plays a physiological role in the testis and highlight that a normal balance of glucocorticoid activity in the testis is important for steroidogenesis.

Mechanisms of Xiong-Pi-Fang in treating coronary heart disease associated with depression: A systematic pharmacology strategy and in vivo pharmacological validation

BACKGROUND

Coronary heart disease (CHD) and depression are very common and often co-existing disorders. Xiong-Pi-Fang (XPF), a therapeutic classical traditional Chinese medicine (TCM) formula, has shown satisfactory efficacy in treating CHD associated with depression. However, its mechanism of action is still unknown.

PURPOSE

To employ a systematic pharmacology approach for identifying the action mechanisms of XPF in treating CHD associated with depression.

METHODS

We used a systematic pharmacology approach to identify the potential active mechanisms of XPF in treating CHD with depression. Potential active compounds in XPF and the diseases targets were screened using relevant databases to build corresponding pathways, following the experiments that were conducted to confirm whether the presumptive results of systemic pharmacology were correct.

RESULTS

Network pharmacology predicted 42 key targets and 20 signaling pathways involved in XPF-mediated treatment, with IL-6/JAK2/STAT3/HIF-1α/VEGF-A pathway significantly affected. The common influences were hypothalamic-pituitary-adrenal axis (HPA axis) and glucocorticoid signaling, validated through chronic unexpected mild stress (CUMS) with isoprenaline (ISO) for inducing CHD within the depression model in rats. In addition, XPF intake reduced depressive-like behaviors and improved ECG ischemic changes. Furthermore, XPF exerted some anti-inflammatory effects by inhibiting the interleukin-6 (IL-6) induced phosphorylation of janus kinase 2 (JAK2) and signal transducer and activator of transcription 3 (STAT3), ultimately downregulating hypoxia-inducible factor 1-α (HIF-1α) and vascular endothelial growth factor-A (VEGF-A) activation. The dysfunctional HPA axis feedback loop was also regulated, which enhanced the glucocorticoid receptor (GR) expression. In contrast, it improved glucocorticoid resistance by reducing the mineralocorticoid receptor expression.

CONCLUSIONS

Suppressing IL-6 release and maintaining the HPA feedback loop balance could be the primary mechanism of XPF against CHD with depression. The significance of the IL-6 and HPA axis identified indicates their potential as essential targets for CHD therapy with depression.

Transcriptomic Studies of Antidepressant Action in Rodent Models of Depression: A First Meta-Analysis

Antidepressants (ADs) are, for now, the best everyday treatment we have for moderate to severe major depressive episodes (MDEs). ADs are among the most prescribed drugs in the Western Hemisphere; however, the trial-and-error prescription strategy and side-effects leave a lot to be desired. More than 60% of patients suffering from major depression fail to respond to the first AD they are prescribed. For those who respond, full response is only observed after several weeks of treatment. In addition, there are no biomarkers that could help with therapeutic decisions; meanwhile, this is already true in cancer and other fields of medicine. For years, many investigators have been working to decipher the underlying mechanisms of AD response. Here, we provide the first systematic review of animal models. We thoroughly searched all the studies involving rodents, profiling transcriptomic alterations consecutive to AD treatment in naïve animals or in animals subjected to stress-induced models of depression. We have been confronted by an important heterogeneity regarding the drugs and the experimental settings. Thus, we perform a meta-analysis of the AD signature of fluoxetine (FLX) in the hippocampus, the most studied target. Among genes and pathways consistently modulated across species, we identify both old players of AD action and novel transcriptional biomarker candidates that warrant further investigation. We discuss the most prominent transcripts (immediate early genes and activity-dependent synaptic plasticity pathways). We also stress the need for systematic studies of AD action in animal models that span across sex, peripheral and central tissues, and pharmacological classes.

Glucocorticoids and COVID-19

Coronavirus Disease 19 (COVID-19) is associated with high morbidity and mortality rates globally, representing the greatest health and economic challenge today. Several drugs are currently approved for the treatment of COVID-19. Among these, glucocorticoids (GCs) have received particular attention due to their anti-inflammatory and immunosuppressive effects. In fact, GC are widely used in current clinical practice to treat inflammatory, allergic and autoimmune diseases. Major mechanisms of GC action include inhibition of innate and adaptive immune activity. In particular, an important role is played by the inhibition of pro-inflammatory cytokines and chemokines, and the induction of proteins with anti-inflammatory activity. Overall, as indicated by various national and international regulatory agencies, GCs are recommended for the treatment of COVID-19 in patients requiring oxygen therapy, with or without mechanical ventilation. Regarding the use of GCs for the COVID-19 treatment of non-hospitalized patients at an early stage of the disease, many controversial studies have been reported and regulatory agencies have not recommended their use. The decision to start GC therapy should be based not only on the severity of COVID-19 disease, but also on careful considerations of the benefit/risk profile in individual patients, including monitoring of adverse events. In this review we summarize the effects of GCs on the major cellular and molecular components of the inflammatory/immune system, the benefits and the adverse common reactions in the treatment of inflammatory/autoimmune diseases, as well as in the management of COVID-19.

Blood-Brain Barrier Dysfunction in the Pathogenesis of Major Depressive Disorder

Major depression represents a complex and prevalent psychological disease that is characterized by persistent depressed mood, impaired cognitive function and complicated pathophysiological and neuroendocrine alterations. Despite the multifactorial etiology of depression, one of the most recent factors to be identified as playing a critical role in the development of depression is blood-brain barrier (BBB) disruption. The occurrence of BBB integrity disruption contributes to the disturbance of brain homeostasis and leads to complications of neurological diseases, such as stroke, chronic neurodegenerative disorders, neuroinflammatory disorders. Recently, BBB associated tight junction disruption has been shown to implicate in the pathophysiology of depression and contribute to increased susceptibility to depression. However, the underlying mechanisms and importance of BBB damage in depression remains largely unknown. This review highlights how BBB disruption regulates the depression process and the possible molecular mechanisms involved in development of depression-induced BBB dysfunction. Moreover, insight on promising therapeutic targets for treatment of depression with associated BBB dysfunctions are also discussed.

Review of Herbal Medicines for the Treatment of Depression

Depression, a mental illness that is receiving increasing attention, is caused by multiple factors and genes and adversely affects social life and health. Several hypotheses have been proposed to clarify the pathogenesis of depression, and various synthetic antidepressants have been introduced to treat patients with depression. However, these drugs are effective only in a proportion of patients and fail to achieve complete remission. Recently, herbal medicines have received much attention as alternative treatments for depression because of their fewer side effects and lower costs. In this review, we have mainly focused on the herbal medicines that have been proven in clinical studies (especially randomized controlled trials and preclinical studies) to have antidepressant effects; we also describe the potential mechanisms of the antidepressant effects of those herbal medicines; the cellular and animal model of depression; and the development of novel drug delivery systems for herbal antidepressants. Finally, we objectively elaborate on the challenges of using herbal medicines as antidepressants and describe the benefits, adverse effects, and toxicity of these medicines.

Chronic Piromelatine Treatment Alleviates Anxiety, Depressive Responses and Abnormal Hypothalamic-Pituitary-Adrenal Axis Activity in Prenatally Stressed Male and Female Rats

The prenatal stress (PNS) model in rodents can induce different abnormal responses that replicate the pathophysiology of depression. We applied this model to evaluate the efficacy of piromelatine (Pir), a novel melatonin analog developed for the treatment of insomnia, in male and female offspring. Adult PNS rats from both sexes showed comparable disturbance associated with high levels of anxiety and depressive responses. Both males and females with PNS demonstrated impaired feedback inhibition of the hypothalamic-pituitary-adrenal (HPA) axis compared to the intact offspring and increased glucocorticoid receptors in the hippocampus. However, opposite to female offspring, the male PNS rats showed an increased expression of mineralocorticoid receptors in the hippocampus. Piromelatine (20 mg/kg, i.p., for 21 days injected from postnatal day 60) attenuated the high anxiety level tested in the open field, elevated plus-maze and light-dark test, and depressive-like behavior in the sucrose preference and the forced swimming tests in a sex-specific manner. The drug reversed to control level stress-induced increase of plasma corticosterone 120 min later in both sexes. Piromelatine also corrected to control level the PNS-induced alterations of corticosteroid receptors only in male offspring. Our findings suggest that the piromelatine treatment exerts beneficial effects on impaired behavioral responses and dysregulated HPA axis in both sexes, while it corrects the PNS-induced changes in the hippocampal corticosteroid receptors only in male offspring.

Neuromodulation and hippocampal neurogenesis in depression: A scoping review

The 'neurogenesis hypothesis of depression' emphasizes the importance of upregulated hippocampal neurogenesis for the efficacy of antidepressant treatment. Neuromodulation is a promising therapeutic method that stimulates neural circuitries to treat neuropsychiatric illnesses. We conducted a scoping review on the neurogenic and antidepressant outcomes of neuromodulation in animal models of depression. PubMed, Web of Science, and PsycInfo were comprehensively searched for full-text English articles from inception to October 5, 2021. Data screening and extraction were conducted independently by two researchers. Seventeen eligible studies were included in this review. The majority of studies used non-invasive neuromodulation (n = 14) and assessed neurogenesis using neural proliferation (n = 16) and differentiation markers (n = 9). Limited reports (n = 2) used neurogenic inhibitors to evaluate the role of neurogenesis on the depressive-like behavioral outcomes. Overall, neuromodulation substantially effectuated both hippocampal cell proliferation and antidepressant-like behavior in animal models of depression, with some providing evidence for enhanced neuronal differentiation and maturation. The proposed neurogenic-related mechanisms mediating the neuromodulation efficacies included neurotrophic processes, anti-apoptotic pathways, and normalization of HPA axis functions. Further research is warranted to explore the role of neuromodulation-induced neurogenic effects on treatment efficacies and to elucidate the underlying molecular mechanisms.

Mental Health Benefits of Breastfeeding: A Literature Review

Pregnancy is typically viewed as a time of emotional well-being for prospective mothers, but for some, this period can negatively impact mental health. However, the relationship between postpartum mental health and breastfeeding is not clearly understood. Considering that many health authorities recommend breastfeeding, clearly defining this relationship is important. This review aims to illustrate the effects that breastfeeding has on the mental health of postpartum mothers. An extensive computerized search was performed through databases of PubMed, CINAHL, and Medline. All studies conducted to determine the effects of breastfeeding on mental health were screened and included in this review. Search terms related to breastfeeding, postpartum, and mental health were used. This review on breastfeeding and postpartum depression (PPD) begins by discussing the correlation between lactation and the maternal stress response. Another component discussed is the duration of breastfeeding and its importance in limiting PPD symptoms. The review then shifts to focus more on the psychological aspects of breastfeeding, notably on changes to the sleep-wake cycle and mother-infant interactions. The final part of the review emphasizes the danger that early breastfeeding cessation imposes on a mother’s mental health, portraying how prenatal and early-onset postpartum depression may lead to early breastfeeding cessation. This composite collection of studies clarifies the importance of breastfeeding in reducing the incidence and severity of maternal postpartum depression.

An Investigation of the Anti-Depressive Properties of Phenylpropanoids and Flavonoids in Hemerocallis citrina Baroni

The World Health Organization predicts that over the next several years, depression will become the most important mental health issue globally. Growing evidence shows that the flower buds of Hemerocallis citrina Baroni (H. citrina) possess antidepressant properties. In the search for new anti-depression drugs, a total of 15 phenylpropanoids and 22 flavonoids were isolated and identified based on spectral data (1D and 2D NMR, HR-ESI-MS, UV) from H. citrina. Among them, compound 8 was a novel compound, while compounds 1-4, 6, 9, 10, 15, 17, 24-26, 28, and 37 were isolated for the first time from Hemerocallis genus. To study the antidepressant activity of phenylpropanoids and flavonoids fractions from H. citrina, macroporous resin was used to enrich them under the guidance of UV characteristics. UHPLC-MS/MS was applied to identify the constituents of the enriched fractions. According to behavioral tests and biochemical analyses, it showed that phenylpropanoid and flavonoid fractions from H. citrina can improve the depressive-like mental state of chronic unpredictable mild stress (CUMS) rats. This might be accomplished by controlling the amounts of the inflammatory proteins IL-6, IL-1β, and TNF-α in the hippocampus as well as corticosterone in the serum. Thus, the monomer compounds were tested for their anti-neuroinflammatory activity and their structure-activity relationship was discussed in further detail.

Psychobiological foundations of coping and emotion regulation: Links to maltreatment and depression in a racially diverse, economically disadvantaged sample of adolescent girls

Adolescent risk for depression and passive or active suicidal ideation (PASI) involves disturbance across multiple systems (e.g., arousal regulatory, affective valence, neurocognitive). Exposure to maltreatment while growing up as a child or teenager may potentiate this risk by noxiously impacting these systems. However, research exploring how coordinated disturbance across these systems (i.e., profiles) might be uniquely linked to depressogenic function, and how past maltreatment contributes to such disturbance, is lacking. Utilizing a racially diverse, economically disadvantaged sample of adolescent girls, this person-centered study identified psychobiological profiles and linked them to maltreatment histories, as well as current depressive symptoms and PASI. Girls (N = 237, Mage=13.98, SD=0.85) who were non-depressed/non-maltreated (15.1%), depressed/non-maltreated (40.5%), or depressed/maltreated (44.4%) provided morning saliva samples, completed questionnaires, a clinical interview, and a neurocognitive battery. Latent profile analysis of girls' morning cortisol:C-reactive protein ratio, positive and negative affect levels, and attentional set-shifting ability revealed four profiles. Relative to Normative (66.6%), girls exhibiting a Pro-inflammatory Affective Disturbance (13.1%), Severe Affective Disturbance (10.1%), or Hypercortisol Affective Neurocognitive Disturbance (n = 24, 10.1%) profile reported exposure to a greater number of maltreatment subtypes while growing up. Girls exhibiting these dysregulated profiles were also more likely (relative to Normative) to report current depressive symptoms (all three profiles) and PASI (only Pro-inflammatory Affective Disturbance and Hypercortisol Affective Neurocognitive Disturbance). Of note, girls' cognitive reappraisal utilization moderated profile membership-depression linkages (depressive symptoms, but not PASI). A synthesis of the findings is presented alongside implications for person-centered tailoring of intervention efforts.

Glucocorticoid receptor expression as an integrative measure to assess glucocorticoid plasticity and efficiency in evolutionary endocrinology: A perspective

Organisms have to cope with the changes that take place in their environment in order to keep their physical and psychological stability. In vertebrates, the hypothalamic-pituitary-adrenal (HPA) axis plays a key role in mediating phenotypic adjustments to environmental changes, primarily by regulating glucocorticoids (GCs). Although circulating GCs have widely been used as proxy for individual health and fitness, our understanding of HPA regulation is still very limited, especially in free-living animals. Circulating GCs only exert their actions when they are bound to receptors, and therefore, GC receptors play a pivotal role mediating HPA regulation and GC downstream phenotypic changes. Because under challenging conditions GC actions (as well as negative feedback activation) occur mainly through binding to low-affinity glucocorticoid receptors (GR), we propose that GR activity, and in particular GR expression, may play a crucial role in GC regulation and dynamics, and be ultimately related to organismal capacity to appropriately respond to environmental changes. Thus, we suggest that GR expression will provide more comprehensive information of GC variation and function. To support this idea, we compile previous evidence demonstrating the fundamental role of GR on GC responses and the fine-tuning of circulating GCs. We also make predictions about the phenotypic differences in GC responsiveness - and ultimately HPA regulation capacity - associated with differences in GR expression, focusing on GC plasticity and efficiency. Finally, we discuss current priorities and limitations of integrating measures of GR expression into evolutionary endocrinology and ecology studies, and propose further research directions towards the use of GR expression and the study of the mechanisms regulating GR activity to gather information on coping strategies and stress resilience. Our goals are to provide an integrative perspective that will prompt reconsideration on the ecological and physiological interpretation of current GC measurements, and motivate further research on the role of GR in tuning individual responses to dynamic environments.

Luteolin-7-O-Glucuronide Improves Depression-like and Stress Coping Behaviors in Sleep Deprivation Stress Model by Activation of the BDNF Signaling

Stress exposure is a major risk factor for mental disorders such as depression. Because of the limitations of classical antidepressants such as side effects, low efficacy, and difficulty in long-term use, new natural medicines and bioactive molecules from plants with greater safety and efficacy have recently attracted attention. Luteolin-7-O-glucuronide (L7Gn), a bioactive molecule present in Perilla frutescens, is known to alleviate severe inflammatory responses and oxidative stress in macrophages. However, its antistress and antidepressant effects have not been elucidated. The present study aims to explore the antidepressant the effect of L7Gn on stress-induced behaviors and the underlying mechanism in a mouse sleep deprivation (SD) model. L7Gn treatment improved depression-like and stress coping behaviors induced by SD stress, as confirmed by the tail suspension test and forced swimming test. Furthermore, L7Gn treatment reduced the blood corticosterone and hippocampal proinflammatory cytokine levels which were increased by SD stress, and L7Gn also increased the mRNA and protein levels of hippocampal brain-derived neurotrophic factor (BDNF) which were reduced by SD stress. Additionally, treatment with L7Gn resulted in increases in the phosphorylation of tropomyosin-related kinase B (TrkB), extracellular signal-regulated kinase (ERK), and cAMP response element-binding protein (CREB), which are downstream molecules of BDNF signaling. These findings suggest that L7Gn have therapeutic potential for SD-induced stress, via activating the BDNF signaling.

Early life adversity shapes neural circuit function during sensitive postnatal developmental periods

Early life adversity (ELA) is a major risk factor for mental illness, but the neurobiological mechanisms by which ELA increases the risk for future psychopathology are still poorly understood. Brain development is particularly malleable during prenatal and early postnatal life, when complex neural circuits are being formed and refined through an interplay of excitatory and inhibitory neural input, synaptogenesis, synaptic pruning, myelination, and neurogenesis. Adversity that influences these processes during sensitive periods of development can thus have long-lasting and pervasive effects on neural circuit maturation. In this review, we will discuss clinical and preclinical evidence for the impact of ELA on neural circuit formation with a focus on the early postnatal period, and how long-lasting impairments in these circuits can affect future behavior. We provide converging evidence from human and animal studies on how ELA alters the functional development of brain regions, neural circuits, and neurotransmitter systems that are crucial for cognition and affective behavior, including the hippocampus, the hypothalamus-pituitary-adrenal (HPA) axis, neural networks of fear responses and cognition, and the serotonin (5-HT) system. We also discuss how gene-by-environment (GxE) interactions can determine individual differences in susceptibility and resilience to ELA, as well as molecular pathways by which ELA regulates neural circuit development, for which we emphasize epigenetic mechanisms. Understanding the molecular and neurobiological mechanisms underlying ELA effects on brain function and psychopathology during early postnatal sensitive periods may have great potential to advance strategies to better treat or prevent psychiatric disorders that have their origin early in life.

Gene Dysregulation in the Adult Rat Paraventricular Nucleus and Amygdala by Prenatal Exposure to Dexamethasone

Fetal programming is the concept that maternal stressors during critical periods of fetal development can alter offspring phenotypes postnatally. Excess glucocorticoids can interact with the fetus to effect genetic and epigenetic changes implicated in adverse developmental outcomes. The present study investigates how chronic exposure to the synthetic glucocorticoid dexamethasone during late gestation alters the expression of genes related to behavior in brain areas relevant to the regulation and function of the hypothalamic–pituitary–adrenal axis. Pregnant Wistar Kyoto rats received subcutaneous injections of dexamethasone (100 μg/kg) daily from gestational day 15–21 or vehicle only as sham controls. The amygdala and paraventricular nucleus (PVN) were micro-punched to extract mRNA for reverse transcription and quantitative polymerase chain reaction for the analysis of the expression of specific genes. In the PVN, the expression of the glucocorticoid receptor NR3C1 was downregulated in female rats in response to programming. The expression of CACNA1C encoding the Ca_v1.2 pore subunit of L-type voltage-gated calcium channels was downregulated in male and female rats prenatally exposed to dexamethasone. Collectively, the results suggest that prenatal exposure to elevated levels of glucocorticoids plays a role in the dysregulation of the hypothalamic–pituitary–adrenal axis and potentially learning and memory by altering the expression of specific genes within the amygdala and PVN.

Effects of miR-124-3p Silencing on Neuronal Damage in the Hippocampus of Depression Rats by Regulating STAT3 Gene

Objective

A large amount of evidence shows that the abnormal expression of miRNA plays an important role in the development of depression. Therefore, we investigated the effect of miR-124-3p on neuronal damage in the hippocampus of depression rats.

Methods

The target genes of miR-124-3p were predicted by the database; the depression model was prepared by subcutaneous injection of corticosterone (CORT), and LV-miR-124-3p asponge lentiviral suspension was given to determine the weight of rats and open-field test, sugar preference experiment, Serum CORT, 5-HT, DA, and NE were measured, observe and record the behavior of rats, including behavior, diet, and hair. The expression of miR-124-3p, STAT3, Bcl-2, and Bax in rat hippocampus was measured. The rat hippocampal neuron cells were extracted and transfected with miR-124-3p inhibitor; the cells were cultured with CORT, and the cell survival rate was evaluated by MTT experiment, and the expressions of miR-124-3p, STAT3, Bcl-2, and Bax in the cells were detected. Luciferase reporter gene verifies the targeted regulation of miR-124-3p on STAT3.

Results

Compared with depression rats, silencing miR-124-3p increased the weight of the rats, increased the number of open-field activities, and significantly improved the general state and pathological state of the rats. The sugar water preference rate was significantly increased, the CORT content in the serum of rats decreased significantly, and the levels of 5-HT, DA, and NE increased significantly. After the treatment of silencing miR-124-3p, the expression level of miR-124-3p was decreased, while the STAT3 mRNA and protein expression levels were increased. And the protein and mRNA expression levels of Bcl-2 were increased, and the Bax protein and mRNA expression were decreased. Cell experiments verified that silencing miR-124-3p increased cell survival, the expression level of miR-124-3p decreased remarkably, while the expression levels of STAT3 mRNA and protein increased significantly. Silencing miR-124-3p reversed the effects of CORT treatment on miR-124-3p and STAT3 in neuronal cells. The luciferase reporter gene experiment confirmed that miR-124-3p targets and regulates STAT3 expression.

Conclusion

Silencing miR-124-3p may protect hippocampal neurons from damage in depression rats by upregulating STAT3 gene.

Effects of Huolisu Oral Solution on Depression-Like Behavior in Rats: Neurotransmitter and HPA Axis

Background: Depression is a common mental disorder, and its morbidity rate is expected to rank second among all mental disorders by 2020. Hence, traditional Chinese medicines gradually attract the attention of many researchers because of their various targets and low toxicity. Huolisu oral solution (HLS) is a Chinese medicine compound preparation, which is present in the Chinese Pharmacopoeia. It is used clinically mainly for the treatment of neurasthenia, perimenopausal syndrome, and insomnia, or depression associated with cerebrovascular disease. Despite the fact that HLS has been used as an antidepressant in clinics, the underlying mechanism is still an untouched domain. To provide a theoretical basis for the clinical application, a series of assessment methods, such as the tail suspension test (TST), forced swim test (FST), and locomotor activity test in mice and rat models of chronic unpredictable mild stress (CUMS), have been conducted in our study.

Objective: The aim of the study was to explore the antidepressive effect and mechanism of HLS.

Methods: CUMS was induced in rats to simulate a depression-like behavior. Neurotransmitters and hormones were detected by enzyme-link immunosorbent assay (ELISA). Pathomorphology examination of the hippocampus was obtained by using the TSView 7 image analysis system. The active ingredients of HLS were also determined by high-performance liquid chromatography (HPLC).

Results: HLS could alleviate the depression-like behavior of the model rats. Biochemical analysis showed that HLS enhanced the levels of 5-hydroxytryptamine (5-HT), norepinephrine (NE), and dopamine (DA) in the hippocampus and diminished these in the serum of the CUMS rats. HLS could also decrease the concentration of corticosterone (CORT), adrenocorticotropic hormone (ACTH), and β-endorphin (β-EP) in blood. The pathohistological examination revealed that the hippocampus and adrenal gland were improved after treatment with HLS.

Conclusions: This study concluded that HLS could alleviate depression-like behaviors in the rats exposed to CUMS, and the potential mechanism may be related to the regulation of the monoamine neurotransmitters, the hypothalamic–pituitary–adrenal (HPA) axis, and the β-EP. These findings hint that HLS is likely to be a potentially effective agent for treating depression.

Cause or consequence? Understanding the role of cortisol in the increased inflammation observed in depression

Glucocorticoids such as cortisol are a class of steroid hormones that play an important role in co-ordinating the body's response to stress. Elevated cortisol levels and increased inflammation have frequently been reported in patients with depression. The currently accepted "glucocorticoid resistance" model posits this increased inflammation as a consequence of reduced sensitivity to cortisol's putative anti-inflammatory action. However, opposing evidence has accumulated that supports a more recent model, which instead proposes that cortisol possesses immune potentiating properties and may thus directly cause the increased inflammation seen in depression. Despite all of this, a clear explanation of the neuroendocrine mechanism that contributes to the development of depression is still lacking and thus requires further investigation in improved future studies.

Suicide: Allostatic regulation and resilience

Suicide is a complex public health problem that is the result of a number of intertwined biopsychosocial factors. The diathesis-stress model suggests that suicide is the result of an interaction between genetic vulnerability and environmental stressors. Chronic stress and trauma contribute to biologic adaptations, including hypothalamus-pituitary-adrenal axis dysregulation, that contribute to the degradation of regulatory mechanisms and promote wear and tear the body, represented by allostatic load (AL). AL has been associated with a number of negative outcomes, including mental health problems and suicide. Fortunately, there are pharmacological and non-pharmacological interventions that are effective at reducing AL and reversing its effects. Thus, AL may provide a construct for supporting early risk identification, prevention, and treatment of suicide. AL biomarkers that are amenable to measurable change, effective treatments to reduce AL and perhaps help prevent suicide, and how to best tailor them to the individual and societal levels are important avenues of therapeutic inquiry.

Tricyclic antidepressants target FKBP51 SUMOylation to restore glucocorticoid receptor activity

FKBP51 is an important inhibitor of the glucocorticoid receptor (GR) signaling. High FKBP51 levels are associated to stress-related disorders, which are linked to GR resistance. SUMO conjugation to FKBP51 is necessary for FKBP51's inhibitory action on GR. The GR/FKBP51 pathway is target of antidepressant action. Thus we investigated if these drugs could inhibit FKBP51 SUMOylation and therefore restore GR activity. Screening cells using Ni²⁺ affinity and in vitro SUMOylation assays revealed that tricyclic antidepressants- particularly clomipramine- inhibited FKBP51 SUMOylation. Our data show that clomipramine binds to FKBP51 inhibiting its interaction with PIAS4 and therefore hindering its SUMOylation. The inhibition of FKBP51 SUMOylation decreased its binding to Hsp90 and GR facilitating FKBP52 recruitment, and enhancing GR activity. Reduction of PIAS4 expression in rat primary astrocytes impaired FKBP51 interaction with GR, while clomipramine could no longer exert its inhibitory action. This mechanism was verified in vivo in mice treated with clomipramine. These results describe the action of antidepressants as repressors of FKBP51 SUMOylation as a molecular switch for restoring GR sensitivity, thereby providing new potential routes of antidepressant intervention.

The Role of Natural Products in Treatment of Depressive Disorder

Depressive disorder is one of the most common psychiatric syndromes that, if left untreated, can cause many disturbances in a person's life. Numerous factors are involved in depression, including inflammation, brain-derived neurotrophic factor (BDNF), GABAergic system, hypothalamic- pituitary-adrenal (HPA) Axis, monoamine neurotransmitters (serotonin (5-HT), noradrenaline, and dopamine). Common treatments for depression are selective serotonin reuptake inhibitors, tricyclic antidepressants, and monoamine oxidase inhibitors, but these drugs have several side effects such as anxiety, diarrhea, constipation, weight loss, and sexual dysfunctions. These agents only reduce the symptoms and temporarily reduce the rate of cognitive impairment associated with depression. As a result, extensive research has recently been conducted on the potential use of antidepressant and sedative herbs. According to the available data, herbs used in traditional medicine can be significantly effective in reducing depression, depressive symptoms and improving patients' performance. The present study provides a summary of biomarkers and therapeutic goals of depression and shows that natural products such as saffron or genipin have antidepressant effects. Some of the useful natural products and their mechanisms were evaluated. Data on various herbs and natural isolated compounds reported to prevent and reduce depressive symptoms is also discussed.

Postweaning social isolation and autism-like phenotype: a biochemical and behavioral comparative analysis

Adolescence is a critical period for brain development. In most mammalian species, disturbances experienced during adolescence constitute a risk factor for several neuropsychiatric disorders. In this study, we compared the biochemical and behavioral profile induced by postweaning social isolation (PWSI) in inbred C57BL/6N mice with that of BTBR mice, a rodent model of autism spectrum disorders. Male C57BL/6N mice were either housed in groups of four or isolated from weaning (postnatal day 21) for four weeks before experimental analyses. After weaning, male BTBR mice were housed four per cage and analyzed at 48 days of age. PWSI reduced hippocampal levels of type 2 metabotropic glutamate (mGlu2) receptors, and glucocorticoid and mineralocorticoid receptors. A similar reduction was seen in group-housed BTBR mice. Plasma corticosterone levels in basal conditions were not influenced by PWSI, but were increased in BTBR mice. Social investigation (total and head sniffing) and the number of ultrasonic vocalizations were reduced in both PWSI mice and age-matched group-housed BTBR mice, indicating a lower social responsiveness in both groups of mice. These results suggest that absence of social stimuli during adolescence induces an endophenotype with social deficit features, which mimics the phenotype of a mouse model of autism spectrum disorders.

Natural products for the treatment of stress-induced depression: Pharmacology, mechanism and traditional use

ETHNOPHARMACOLOGICAL RELEVANCE

Depression, one of the most common psychiatric disorders, is the fourth leading cause of long-term disability worldwide. A series of causes triggered depression, including psychological stress and conflict, as well as biological derangement, among which stress has a pivotal role in the development of depression. Traditional herbal medicine has been used for the treatment of various disorders including depression for a long history with multi-targets, multi-levels and multi-ways, attracting great attention from scholars. Recently, natural products have been commercialized as antidepressants which have become increasingly popular in the world health drug markets. Major research contributions in ethnopharmacology have generated and updated vast amount of data associated with natural products in antidepressant-like activity.

AIMS OF THE REVIEW

This review aims to briefly discuss the pathological mechanism, animal models of stress-induced depression, traditional use of herbal medicines and especially recapitulate the natural products with antidepressant activity and their pharmacological functions and mechanism of action, which may contribute to a better understanding of potential therapeutic effects of natural products and the development of promising drugs with high efficacy and low toxicity for the treatment of stress-induced depression.

MATERIALS AND METHODS

The contents of this review were sourced from electronic databases including PubMed, Sci Finder, Web of Science, Science Direct, Elsevier, Google Scholar, Chinese Knowledge On frastructure (CNKI), Wan Fang, Chinese Scientific and Technological Periodical Database (VIP) and Chinese Biomedical Database (CBM). Additional information was collected from Yao Zhi website (https://db.yaozh.com/). Data were obtained from April 1992 to June 2021. Only English language was applied to the search. The search terms were 'stress-induced depression', 'pathological mechanism' in the title and 'stress', 'depression', 'animal model' and 'natural products' in the whole text.

RESULTS

Stress-induced depression is related to the monoaminergic system, hypothalamic-pituitary-adrenal (HPA) axis, neuronal plasticity and a series of inflammatory factors. Four main types of animal models of stress-induced depression were represented. Fifty-eight bioactive phytochemical compounds, fifty-six herb medicines and five formulas from traditional Chinese medicine were highlighted, which exert antidepressant effects by inhibiting monoamine oxidase (MAO) reaction, alleviating dysfunction of the HPA axis and nerve injury, and possessing anti-inflammatory activities.

CONCLUSIONS

Natural products provide a large number of compounds with antidepressant-like effects, and their therapeutic impacts has been highlighted for a long time. This review summarized the pathological mechanism and animal models of stress-induced depression, and the natural products with antidepressant activity in particular, which will shed light on the action mechanism and clinical potential of these compounds. Natural products also have been a vital and promising source for future antidepressant drug discovery.

Microglia and HPA axis in depression: An overview of participation and relationship

Objectives: This narrative review article provides an overview on the involvement of microglia and the hypothalamic-pituitary-adrenal (HPA) axis in the pathophysiology of depression, as well investigates the mutual relationship between these two entities: how microglial activation can contribute to the dysregulation of the HPA axis, and vice versa.Methods: Relevant studies and reviews already published in the Pubmed electronic database involving the themes microglia, HPA axis and depression were used to meet the objectives.Results: Exposition to stressful events is considered a common factor in the mechanisms proposed to explain the depressive disorder. Stress can activate microglial cells, important immune components of the central nervous system (CNS). Moreover, another system involved in the physiological response to stressors is the hypothalamic-pituitary-adrenal (HPA) axis, the main stress response system responsible for the production of the glucocorticoid hormone (GC). Also, mediators released after microglial activation can stimulate the HPA axis, inducing production of GC. Likewise, high levels of GCs are also capable of activating microglia, generating a vicious cycle.Conclusion: Immune and neuroendocrine systems seems to work in a coordinated manner and that their dysregulation may be involved in the pathophysiology of depression since neuroinflammation and hypercortisolism are often observed in this disorder.

Role of CRF and the hypothalamic-pituitary-adrenal axis in stroke: revisiting temporal considerations and targeting a new generation of therapeutics

Ischaemic neurovascular stroke represents a leading cause of death in the developed world. Preclinical and human epidemiological evidence implicates the corticotropin-releasing factor (CRF) family of neuropeptides as mediators of acute neurovascular injury pathology. Preclinical investigations of the role of CRF, CRF receptors and CRF-dependent activation of the hypothalamic-pituitary-adrenal (HPA) axis have pointed toward a tissue-specific and temporal relationship between activation of these pathways and physiological outcomes. Based on the literature, the major phases of ischaemic stroke aetiology may be separated into an acute phase in which CRF and anti-inflammatory stress signalling are beneficial and a chronic phase in which these contribute to neural degeneration, toxicity and apoptotic signalling. Significant gaps in knowledge remain regarding the pathway, temporality and systemic impact of CRF signalling and stress biology in neurovascular injury progression. Heterogeneity among experimental designs poses a challenge to defining the apparent reciprocal relationship between neurological injury and stress metabolism. Despite these challenges, it is our opinion that the elucidated temporality may be best matched with an antibody against CRF with a half-life of days to weeks as opposed to minutes to hours as with small-molecule CRF receptor antagonists. This state-of-the-art review will take a multipronged approach to explore the expected potential benefit of a CRF antibody by modulating CRF and corticotropin-releasing factor receptor 1 signalling, glucocorticoids and autonomic nervous system activity. Additionally, this review compares the modulation of CRF and HPA axis activity in neuropsychiatric diseases and their counterpart outcomes post-stroke and assess lessons learned from antibody therapies in neurodegenerative diseases.

Protective Efficacy of Spilanthes acmella Murr. Extracts and Bioactive Constituents in Neuronal Cell Death

Spilanthes acmella Murr., a well-known Thai traditional medicine, has been used for treatment of toothache, rheumatism and fever. Diverse pharmacological activities of S. acmella Murr. have been reported. In the present study antioxidative and neuroprotective effects of S. acmella Murr. extracts as well as bioactive scopoletin, vanillic acid and trans-ferulic acid found in the aerial parts of this plant species have been described. Protective effect of S. acmella Murr. extracts and bioactive compounds on dexamethasone induced neuronal cells death was investigated. Different plant crude ethyl acetate (EtOAc) and methanol (MeOH) extracts including pure compounds of S. acmella Murr. were evaluated in human neuroblastoma SH-SY5Y cells. Cytotoxic effects were performed by MTT assay. Mechanisms involved in the antioxidant effects of S. acmella Murr. regarding the activation of antioxidant marker proteins such as SOD2 and SIRT3 were determined using DCFH-DA assay, western blot analysis and immunocytochemistry. Dexamethasone significantly caused the decrease of SH-SY5Y cell viability. Conversely, the increases in reactive oxygen species (ROS), autophagy and apoptosis were observed in dexamethasone-treated cells. S. acmella Murr. MeOH and EtOAc extracts, as well as the bioactive compounds reversed the toxic effect of dexamethasone by increasing the cell viability, SIRT3 protein expression but reducing the ROS, autophagy and apoptosis. This study demonstrated that S. acmella Murr. may exert its protective effects against ROS through SOD2 and SIRT3 signaling pathways in dexamethasone-induced neurotoxicity. S. acmella Murr. may be a candidate therapy for neuroprotection.

A cluster analytic approach to examining the role of cortisol in the development of post-traumatic stress and dysphoria in adult traumatic injury survivors

Identification of specific risk factors for posttraumatic stress disorder (PTSD) versus depression after trauma has been challenging, in part due to the high comorbidity of these disorders. As exposure to trauma triggers activation of the hypothalamic-pituitary-adrenal (HPA)-axis, examining atypical stress responses via HPA-axis hormones, namely cortisol, may help in the delineation of these disorders. Indeed, extant research demonstrates that, following stress, individuals with chronic PTSD exhibit hypocortisolism (e.g., lower cortisol response than controls), while those with chronic depression exhibit hypercortisolism (e.g., higher response than controls). Less is known about the role of cortisol and these seemingly disparate profiles immediately following traumatic injury as well as whether cortisol can be used as a predictor of future development of PTSD versus depression symptoms. In this study cortisol was measured blood from 172 traumatic injury survivors during hospitalization (on average 2.5 days post-injury). PTSD and depression severity were assessed from Clinician Assessed PTSD Scale (CAPS-5) six-eight months later using a two-factor dimensional approach that measures trauma-specific symptoms of PTSD versus dysphoria (akin to depression). Cluster analysis was used to group individuals based on post-injury cortisol, PTSD, and dysphoria. Results demonstrated that trauma survivors who only developed symptoms of dysphoria at six months (with minimal symptoms of PTSD) were differentiated by high post-injury cortisol compared to other groups. By contrast, individuals who developed symptoms of both PTSD and dysphoria were differentiated by low post-injury cortisol and most severe symptoms of PTSD. Findings provide support for the presence of subgroups of trauma survivors defined, in part, by post-trauma cortisol.

Brief Developmental Exposure to Fluoxetine Causes Life-Long Alteration of the Brain Transcriptome in Zebrafish

Fluoxetine (FLX) and other selective serotonin reuptake inhibitors are widely used to treat depressive disorders during pregnancy. Early-life exposure to FLX is known to disrupt the normal function of the stress axis in humans, rodents, and teleosts. We used a zebrafish line with a cortisol-inducible fluorescent transgene to study the effects of developmental daily exposure to FLX (54 µg/L) on the transcriptomic profile of brain tissues in exposed larvae and later as 6-month-old adults. High throughput RNA sequencing was conducted on brain tissues in unstressed and stressed conditions. Long-lasting effects of FLX were observed in telencephalon (Tel) and hypothalamus (Hyp) of adult zebrafish with 1927 and 5055 genes significantly (≥1.2 fold-change, false-discovery p-value < 0.05) dysregulated in unstressed condition, respectively. Similar findings were observed in Hyp with 1245 and 723 genes being significantly dysregulated in stressed adults, respectively. Differentially expressed genes converted to Homo sapiens orthologues were used for Ingenuity Pathway Analysis. The results showed alteration of pathways involved in neuroendocrine signaling, cholesterol metabolism and synaptogenesis. Enriched networks included lipid metabolism, molecular transport, and nervous system development. Analysis of putative upstream transcription regulators showed potential dysregulation of clocka and nr3c1 which control circadian rhythm, stress response, cholesterol metabolism and histone modifications. Several genes involved in epigenetic regulation were also affected by FLX, including dnmt3a, adarb1, adarb2, hdac4, hdac5, hdac8, and atf2. We report life-long disruptive effects of FLX on pathways associated with neuroendocrine signaling, stress response and the circadian rhythm, and all of which are implicated in the development of depressive disorders in humans. Our results raise concern for the persistent endocrine-disrupting potential of brief antidepressant exposure during embryonic development.

Increased Cortisol Response and Low Quality of Life in Women Exposed to Intimate Partner Violence With Severe Anxiety and Depression

BACKGROUND

Intimate partner violence (IPV) is one of the most prevalent forms of violence against women globally and it is considered a public health problem. Because the experience of IPV is stressful and traumatic for victims, they are at high risk of developing alteration of the Hypothalamus-Pituitary-Adrenal (HPA) axis functioning as well as anxiety and depression symptoms. The aim of this study was to compare the quality of life and changes in cortisol response to an acute stressor between women exposed to IPV and non-exposed women. Differences according to symptoms of anxiety and depression including the risk of suicide thoughts, were also analyzed.

METHOD

Our sample size consisted of 130 women (ages 18-68) grouped as follows: 71 women experiencing IPV and 59 women without history of IPV as control group. All participants completed a battery of questionnaires including IPV exposure, anxiety, and depression symptoms (Beck Inventories), as well as quality of life (WHOQOL-BREF). Salivary cortisol levels in response to a cognitive test with verbal, mathematical, and abstract reasoning were measured at four time points.

RESULTS

Women exposed to IPV, with severe anxiety and depression symptoms as well as suicide thoughts, exhibited heightened cortisol response after the cognitive test and reported lower quality of life compared to (i) women experiencing IPV with moderate symptoms of anxiety and depression, who showed a blunted response, and (ii) women without history of IPV with minimal to moderate symptoms, who showed a decreased cortisol profile. Social relationships dimension was in particular the most affected aspect of quality of life.

CONCLUSIONS

Our findings highlight the role of cortisol responses as a complementary biological marker to be associated with severe psychiatric disturbances in women exposed to IPV.

Regulatory effects and potential therapeutic implications of alarin in depression, and arguments on its receptor

Alarin is a pleiotropic peptide involved in a multitude of putative biological activities, notably, it has a regulatory effect on depression-like behaviors. Although further elucidating research is needed, animal-based cumulative evidence has shown the antidepressant-like effects of alarin. In light of its regulatory role in depression, alarin could be used as a promising antidepressant in future treatment for depression. Nevertheless, the available information is still insufficient and the therapeutic relevance of alarin in depression is still of concern. Moreover, a plethora of studies have reported that the actions of alarin, including antidepressant activities, are mediated by a separate yet unidentified receptor, highlighting the need for more extensive research. This review focuses on the current understanding of the regulatory effects and future therapeutic relevance of alarin on depression, and the arguments on its receptors.

Ketamine, but not fluoxetine, rapidly rescues corticosterone-induced impairments on glucocorticoid receptor and dendritic branching in the hippocampus of mice

Although numerous studies have investigated the mechanisms underlying the fast and sustained antidepressant-like effects of ketamine, the contribution of the glucocorticoid receptor (GR) and dendritic branching remodeling to its responses remain to be fully established. This study investigated the ability of a single administration of ketamine to modulate the GR and dendritic branching remodeling and complexity in the hippocampus of mice subjected to chronic corticosterone (CORT) administration. CORT was administered for 21 days, followed by a single administration of ketamine (1 mg ∕kg, i.p.) or fluoxetine (10 mg ∕kg, p.o., conventional antidepressant) in mice. On 22^nd, 24 h after the treatments, GR immunocontent in the hippocampus was analyzed by western blotting, while the dendritic arborization and dendrite length in the ventral and dorsal dentate gyrus (DG) of the hippocampus was analyzed by Sholl analysis. Chronic CORT administration downregulated hippocampal GR immunocontent, but this alteration was completely reversed by a single administration of ketamine, but not fluoxetine. Moreover, CORT administration significantly decreased dendritic branching in the dorsal and ventral DG areas and caused a mild decrease in dendrite length in both regions. Ketamine, but not fluoxetine, reversed CORT-induced dendritic branching loss in the ventral and dorsal DG areas, regions associated with mood regulation and cognitive functions, respectively. This study provides novel evidence that a single administration of ketamine, but not fluoxetine, rescued the impairments on GR and dendritic branching in the hippocampus of mice subjected to chronic CORT administration, effects that may be associated with its rapid antidepressant response.