Glucocorticoid receptor function in vitro in patients with major depression

Glucocorticoid Receptor Down-Regulation Affects Neural Stem Cell Proliferation and Hippocampal Neurogenesis

Dysregulation of the hypothalamic-pituitary-adrenal axis and abnormalities in the glucocorticoid receptor (GR) have been linked to major depressive disorder. Given the critical role of GR in stress response regulation, we investigated the impact of GR changes on neural stem cells (NSCs) proliferation and hippocampal neurogenesis. Stress response was induced using dexamethasone (DEX), a GR agonist, which led to reduced proliferation of neural stem cells and neural progenitor cells, as well as decreased expression of GR. Additionally, a reduction of serum concentration within the culture media resulted in suppressed cell proliferation, accompanied by decreased GR expression. The association between GR expression and cell proliferation was further confirmed through GR siRNA knockdown and overexpression experiments. Furthermore, in vivo studies utilizing young male C57BL/6 mice demonstrated that corticosterone (CORT) (35 μg/ml) administered through drinking water for four weeks induced depression-like behavior, as indicated by increased immobility times in forced swimming and tail suspension tests. CORT exposure led to reduced GR and nestin expression levels, along with diminished numbers of BrdU-positive cells in the hippocampi, indicating impaired hippocampal neurogenesis. Taken together, our findings provide the first evidence that stress-induced downregulation of GR negatively affects neurogenesis by inhibiting NSCs proliferation.

Vitamins C and D Exhibit Similar Antidepressant Effects to Escitalopram Mediated by NOx and FKBPL in a Stress-Induced Mice Model

The aim of this study was to investigate the potential antidepressant and anxiolytic effects of vitamin C and vitamin D in a stress-induced mouse model of depression, while also exploring the association between these effects and the levels of circulating NOx, periostin, and FKBPL. Our findings revealed that both vitamin C and vitamin D exhibited comparable antidepressant effects to escitalopram, a commonly used antidepressant, without demonstrating any anxiolytic effects. The antidepressant properties of vitamin C and vitamin D were linked to the normalization of Nox and FKBPL levels, while the levels of periostin showed no significant correlation. These results are consistent with previous research, indicating that the antidepressant effects of vitamin C and vitamin D may be attributed to their antioxidant and anti-inflammatory properties, as well as their modulation of neurotransmission and norepinephrine release. Additionally, our study uncovered elevated levels of periostin in stress-induced depression, which were only restored to normal levels by escitalopram, suggesting a potential role for periostin in mood disorders. Furthermore, FKBPL and NOx levels were increased in stress-induced depression and normalized by treatment with vitamin C, vitamin D, and escitalopram, indicating their involvement in the stress response and gene expression regulation. However, it is important to acknowledge certain limitations of our research, such as the use of a single depression induction model and limited dosing regimens. Future investigations should focus on examining these markers in specific brain regions, such as the hippocampus and prefrontal cortex, to gain a more comprehensive understanding of their potential implications for depression. Overall, our findings suggest that vitamin C, vitamin D, and escitalopram may possess antidepressant properties mediated by NOx and FKBPL levels, while emphasizing the potential significance of periostin in the context of depression.

Pharmacokinetic Study of Intranasal Dexamethasone and Methylprednisolone Compared with Intravenous Administration: Two Open-Label, Single-Dose, Two-Period, Two-Sequence, Cross-Over Study in Healthy Volunteers

Dexamethasone (DXM) and methylprednisolone (MEP) are potent glucocorticoids used to control several inflammatory conditions. Evidence of delayed DXM reaching the central nervous system (CNS) as well as tachyphylaxis and systemic, undesirable side effects are the main limitations of peripheral delivery. Intranasal administration offers direct access to the brain as it bypasses the blood-brain barrier. The Mucosal Atomization Device is an optimal tool that can achieve rapid absorption into the CNS and the bloodstream across mucosal membranes. This study was designed to evaluate and compare the bioavailability of DXM and MEP after intranasal versus intravenous administration. Two open-label, balanced, randomized, two-treatment, two-period, two-sequence, single-dose, crossover studies were conducted, which involved healthy male and female adult volunteers. After intranasal administration, DXM and MEP were detected in plasma after the first sampling time. Mean peak concentrations of DXM and MEP were 86.61 ng/mL at 60 min and 843.2 ng/mL at 1.5 h post-administration, respectively. DXM and MEP showed high absolute bioavailability, with values of 80% and 95%, respectively. No adverse effects were observed. DXM and MEP systemic bioavailability by intranasal administration was comparable with the intravenous one, suggesting that the intranasal route can be used as a non-invasive and appropriate alternative for systemic drug delivery.

Cellular and immunometabolic mechanisms of inflammation in depression: Preliminary findings from single cell RNA sequencing and a tribute to Bruce McEwen

Inflammation is associated with symptoms of anhedonia, a core feature of major depression (MD). We have shown that MD patients with high inflammation as measured by plasma C-reactive protein (CRP) and anhedonia display gene signatures of metabolic reprograming (e.g., shift to glycolysis) necessary to sustain cellular immune activation. To gain preliminary insight into the immune cell subsets and transcriptomic signatures that underlie increased inflammation and its relationship with behavior in MD at the single-cell (sc) level, herein we conducted scRNA-Seq on peripheral blood mononuclear cells from a subset of medically-stable, unmedicated MD outpatients. Three MD patients with high CRP (>3 mg/L) before and two weeks after anti-inflammatory challenge with the tumor necrosis factor antagonist infliximab and three patients with low CRP (≤3 mg/L) were studied. Cell clusters were identified using a Single Cell Wizard pipeline, followed by pathway analysis. CD14⁺ and CD16⁺ monocytes were more abundant in MD patients with high CRP and were reduced by 29% and 55% respectively after infliximab treatment. Within CD14⁺ and CD16⁺ monocytes, genes upregulated in high CRP patients were enriched for inflammatory (phagocytosis, complement, leukocyte migration) and immunometabolic (hypoxia-inducible factor [HIF]-1, aerobic glycolysis) pathways. Shifts in CD4⁺ T cell subsets included ∼30% and ∼10% lower abundance of CD4⁺ central memory (T_CM) and naïve cells and ∼50% increase in effector memory-like (T_EM-like) cells in high versus low CRP patients. T_CM cells of high CRP patients displayed downregulation of the oxidative phosphorylation (OXPHOS) pathway, a main energy source in this cell type. Following infliximab, changes in the number of CD14⁺ monocytes and CD4⁺ T_EM-like cells predicted improvements in anhedonia scores (r = 1.0, p < 0.001). In sum, monocytes and CD4⁺ T cells from MD patients with increased inflammation exhibited immunometabolic reprograming in association with symptoms of anhedonia. These findings are the first step toward determining the cellular and molecular immune pathways associated with inflammatory phenotypes in MD, which may lead to novel immunomodulatory treatments of psychiatric illnesses with increased inflammation.

Pedicularis resupinata Extract Prevents Depressive-like Behavior in Repeated Corticosterone-Induced Depression in Mice: A Preliminary Study

Excessive corticosterone (CORT), resulting from a dysregulated hypothalamic–pituitary–adrenal (HPA) axis, is associated with cognitive impairment and behavioral changes, including depression. In Korean oriental medicine, Pedicularis resupinata is used for the treatment of inflammatory diseases such as rheumatoid arthritis. However, the antidepressant properties of P. resupinata have not been well characterized. Here, the antidepressant-like effects of P. resupinata extract (PRE) were evaluated in terms of CORT-induced depression using in vivo models. HPLC confirmed that acteoside, a phenylethanoid glycoside, was the main compound from PRE. Male ICR mice (8 weeks old) were injected with CORT (40 mg/kg, i.p.) and orally administered PRE daily (30, 100, and 300 mg/kg) for 21 consecutive days. Depressive-like behaviors were evaluated using the open-field test, sucrose preference test, passive avoidance test, tail suspension test, and forced swim test. Treatment with a high dose of PRE significantly alleviated CORT-induced, depressive-like behaviors in mice. Additionally, repeated CORT injection markedly reduced brain-derived neurotrophic factor levels, whereas total glucocorticoid receptor (GR) and GR phosphorylation at serine 211 were significantly increased in the mice hippocampus but improved by PRE treatment. Thus, our findings suggest that PRE has potential antidepressant-like effects in CORT-induced, depressive-like behavior in mice.

A new model for the HPA axis explains dysregulation of stress hormones on the timescale of weeks

Stress activates a complex network of hormones known as the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis is dysregulated in chronic stress and psychiatric disorders, but the origin of this dysregulation is unclear and cannot be explained by current HPA models. To address this, we developed a mathematical model for the HPA axis that incorporates changes in the total functional mass of the HPA hormone-secreting glands. The mass changes are caused by HPA hormones which act as growth factors for the glands in the axis. We find that the HPA axis shows the property of dynamical compensation, where gland masses adjust over weeks to buffer variation in physiological parameters. These mass changes explain the experimental findings on dysregulation of cortisol and ACTH dynamics in alcoholism, anorexia, and postpartum. Dysregulation occurs for a wide range of parameters and is exacerbated by impaired glucocorticoid receptor (GR) feedback, providing an explanation for the implication of GR in mood disorders. These findings suggest that gland-mass dynamics may play an important role in the pathophysiology of stress-related disorders.

The interaction of child abuse and rs1360780 of the FKBP5 gene is associated with amygdala resting-state functional connectivity in young adults

Extensive research has demonstrated that rs1360780, a common single nucleotide polymorphism within the FKBP5 gene, interacts with early-life stress in predicting psychopathology. Previous results suggest that carriers of the TT genotype of rs1360780 who were exposed to child abuse show differences in structure and functional activation of emotion-processing brain areas belonging to the salience network. Extending these findings on intermediate phenotypes of psychopathology, we examined if the interaction between rs1360780 and child abuse predicts resting-state functional connectivity (rsFC) between the amygdala and other areas of the salience network. We analyzed data of young European adults from the general population (N = 774; mean age = 18.76 years) who took part in the IMAGEN study. In the absence of main effects of genotype and abuse, a significant interaction effect was observed for rsFC between the right centromedial amygdala and right posterior insula (p < .025, FWE-corrected), which was driven by stronger rsFC in TT allele carriers with a history of abuse. Our results suggest that the TT genotype of rs1360780 may render individuals with a history of abuse more vulnerable to functional changes in communication between brain areas processing emotions and bodily sensations, which could underlie or increase the risk for psychopathology.

The hypothalamus and its role in hypertension

For the majority of hypertensive patients, the etiology of their disease is unknown. The hypothalamus is a central structure of the brain which provides an adaptive, integrative, autonomic, and neuroendocrine response to any fluctuations in physiological conditions of the external or internal environment. Hypothalamic insufficiency leads to severe metabolic and functional disorders, including persistent increase in blood pressure. Here, we discuss alterations in the neurochemical organization of the paraventricular and suprachiasmatic nucleus in the hypothalamus of patients who suffered from essential hypertension and died suddenly due to acute coronary failure. The changes observed are hypothesized to contribute to the pathogenesis of disease.

Nod-like receptors are critical for gut-brain axis signalling in mice

KEY POINTS

•Nucleotide binding oligomerization domain (Nod)-like receptors regulate cognition, anxiety and hypothalamic-pituitary-adrenal axis activation. •Nod-like receptors regulate central and peripheral serotonergic biology. •Nod-like receptors are important for maintenance of gastrointestinal physiology. •Intestinal epithelial cell expression of Nod1 receptors regulate behaviour.

ABSTRACT

Gut-brain axis signalling is critical for maintaining health and homeostasis. Stressful life events can impact gut-brain signalling, leading to altered mood, cognition and intestinal dysfunction. In the present study, we identified nucleotide binding oligomerization domain (Nod)-like receptors (NLR), Nod1 and Nod2, as novel regulators for gut-brain signalling. NLR are innate immune pattern recognition receptors expressed in the gut and brain, and are important in the regulation of gastrointestinal physiology. We found that mice deficient in both Nod1 and Nod2 (NodDKO) demonstrate signs of stress-induced anxiety, cognitive impairment and depression in the context of a hyperactive hypothalamic-pituitary-adrenal axis. These deficits were coupled with impairments in the serotonergic pathway in the brain, decreased hippocampal cell proliferation and immature neurons, as well as reduced neural activation. In addition, NodDKO mice had increased gastrointestinal permeability and altered serotonin signalling in the gut following exposure to acute stress. Administration of the selective serotonin reuptake inhibitor, fluoxetine, abrogated behavioural impairments and restored serotonin signalling. We also identified that intestinal epithelial cell-specific deletion of Nod1 (VilCre⁺ Nod1^f/f ), but not Nod2, increased susceptibility to stress-induced anxiety-like behaviour and cognitive impairment following exposure to stress. Together, these data suggest that intestinal epithelial NLR are novel modulators of gut-brain communication and may serve as potential novel therapeutic targets for the treatment of gut-brain disorders.

The human stress response

The human stress response has evolved to maintain homeostasis under conditions of real or perceived stress. This objective is achieved through autoregulatory neural and hormonal systems in close association with central and peripheral clocks. The hypothalamic-pituitary-adrenal axis is a key regulatory pathway in the maintenance of these homeostatic processes. The end product of this pathway - cortisol - is secreted in a pulsatile pattern, with changes in pulse amplitude creating a circadian pattern. During acute stress, cortisol levels rise and pulsatility is maintained. Although the initial rise in cortisol follows a large surge in adrenocorticotropic hormone levels, if long-term inflammatory stress occurs, adrenocorticotropic hormone levels return to near basal levels while cortisol levels remain raised as a result of increased adrenal sensitivity. In chronic stress, hypothalamic activation of the pituitary changes from corticotropin-releasing hormone-dominant to arginine vasopressin-dominant, and cortisol levels remain raised due at least in part to decreased cortisol metabolism. Acute elevations in cortisol levels are beneficial to promoting survival of the fittest as part of the fight-or-flight response. However, chronic exposure to stress results in reversal of the beneficial effects, with long-term cortisol exposure becoming maladaptive, which can lead to a broad range of problems including the metabolic syndrome, obesity, cancer, mental health disorders, cardiovascular disease and increased susceptibility to infections. Neuroimmunoendocrine modulation in disease states and glucocorticoid-based therapeutics are also discussed.

Digging deeper in the differential effects of inflammatory and psychosocial stressors in remitted depression: Effects on cognitive functioning

BACKGROUND

Major Depressive Disorder (MDD) covers a wide spectrum of symptoms, including cognitive dysfunction, which can persist during remission. Both inflammatory states and psychosocial stress play a role in MDD pathogenesis.

METHODS

The effects of inflammatory (i.e., Salmonella typhi vaccine) and psychosocial stressor (i.e., Trier Social Stress Test), as well as their combination were investigated on cognition in women (aged 25-45 years, n = 21) with (partially) remitted MDD and healthy controls (n = 18) in a single-blind placebo-controlled study. In a crossover design, patients received on the first day one of the aforementioned interventions and on the other day a placebo, or vice versa, with a washout period of 7-14 days. Short-term and verbal memory, working memory, attention, verbal fluency, information processing speed, psychomotor function, and measures of attentional bias to emotions were measured. Exploratory analyses were performed to assess the correlation between biomarkers of inflammation and the Hypothalamic-Pituitary-Adrenal axis and cognitive functioning.

RESULTS

In patients, inflammatory stress decreased information processing speed and verbal memory, and increased working memory; after psychosocial stress, there was an increase in attention. There was also an increased negative attentional bias in patients after inflammatory stress. Neither stressor had any effect in controls.

LIMITIATIONS

Limitations are the relatively small sample size and antidepressant use by a part of the participants. The effects of the stressors were also measured a relatively short period after administration.

CONCULSION

Patients were sensitive to the cognitive effects of inflammation and psychosocial stress on cognition, while controls were not.

Genetic Variant of Glucocorticoid Receptor Gene at rs41423247 and Its Association with Major Depressive Disorder: A Case-Control Study

Background

Extensive distribution of glucocorticoid receptors (GCRs) in different brain areas along with disruption of hypothalamic-pituitary-adrenal (HPA) axis in major depressive disorder (MDD) and the cross talk between GCRs and HPA proposes genetic variants of GC receptor genes as potential contributors in MDD. Among the GCR polymorphisms, rs41423247, rs6195 and rs6189/rs6190 are suggested to be involved in MDD.

Materials and Methods

We investigated the association between rs41423247, rs6195 and rs6189/rs6190 and MDD in a case-control study. One hundred MDD patients along with 100 healthy individuals were enrolled in this study. genetic variants of rs41423247, rs6195 and rs6189/rs6190 were determined in extracted DNAs using PCR-RFLP.

Result

The prevalence of heterozygote and mutant carriers of rs41423247 were significantly and by 1.9 fold greater in cases versus controls (P=0.033; OR; 95%CI=1.9; 1.1-3.3). Moreover, carriers of the mutant (G) allele were by 1.8 fold more prevalent in MDD group (P=0.013; OR;95%CI=1.8; 1.1-2.8).

Conclusion

Specific carriers of rs41423247 might be more susceptible to developing MDD. This supports the hypothesis of the involvement of GCRs in pathophysiology of MDD.

Pro-inflammatory Monocyte Phenotype and Cell-Specific Steroid Signaling Alterations in Unmedicated Patients With Major Depressive Disorder

Several lines of evidence have strongly implicated inflammatory processes in the pathobiology of major depressive disorder (MDD). However, the cellular origin of inflammatory signals and their specificity remain unclear. We examined the phenotype and glucocorticoid signaling in key cell populations of the innate immune system (monocytes) vs. adaptive immunity (T cells) in a sample of 35 well-characterized, antidepressant-free patients with MDD and 35 healthy controls individually matched for age, sex, smoking status and body mass index. Monocyte and T cell phenotype was assessed by flow cytometry. Cell-specific steroid signaling was determined by mRNA expression of pre-receptor regulation (11β-hydroxysteroid dehydrogenase type 1; 11β -HSD1), steroid receptor expression [glucocorticoid receptor (GR) and mineralocorticoid receptor (MR)], and the downstream target glucocorticoid-induced leucine-zipper (GILZ). We also collected salivary cortisol samples (8:00 a.m. and 10:00 p.m.) on two consecutive days. Patients showed a shift toward a pro-inflammatory phenotype characterized by higher frequency and higher absolute numbers of non-classical monocytes. No group differences were observed in major T cell subset frequencies and phenotype. Correspondingly, gene expression indicative of steroid resistance (i.e., lower expression of GR and GILZ) in patients with MDD was specific to monocytes and not observed in T cells. Monocyte phenotype and steroid receptor expression was not related to cortisol levels or serum levels of IL-6, IL-1β, or TNF-α. Our results thus suggest that in MDD, cells of the innate and adaptive immune system are differentially affected with shifts in monocyte subsets and lower expression of steroid signaling related genes.

Correlations between changes in the hypothalamic-pituitary-adrenal axis and neurochemistry of the anterior cingulate gyrus in postpartum depression

BACKGROUND

This study aimed to investigate associations between indicators of hypothalamic-pituitary-adrenal axis (HPA) functioning and metabolite levels in the anterior cingulate gyrus (ACG) of women with postpartum depression (PPD).

METHODS

The sample (mean age = 28.5 ± 4.6 years) consisted of 20 women with PPD and 19 postpartum euthymic (PPE) women. Brain metabolites were quantified by proton magnetic resonance spectroscopy (¹H-MRS). Salivary cortisol samples were collected upon awakening and 30 min and 12 h later, at 20.6 ± 6.6 (PPD) and 23.0 ± 7.4 (PPE) weeks after childbirth.

RESULTS

There were no significant differences between groups in respect to metabolite levels in the ACG. Compared with PPE, PPD women had less diurnal variation (DVr%). In the PPD group, positive correlations were found between DVr% and myo-inositol (mI/Cr) levels, and between cortisol awakening response (CARi%) and glutamate + glutamine (Glx/Cr) levels. The correlation between CARi% and Glx/Cr remained significant even after controlling for the interval, in weeks, from birth and MR spectroscopy and to hormonal data collection, and the use of contraceptives.

LIMITATIONS

The limitations of the study include the small sample size and the use of oral contraceptives by around half of the sample.

CONCLUSIONS

In the remote postpartum period (mean 21.8 ± 6.9 weeks) and in the presence of depressive episodes, the decreased responsiveness of the HPA axis after awakening and a smaller decrease in cortisol levels over the day were associated with lower levels of metabolites in the ACG. These results may contribute to the development of biological models to explain the etiology of PPD.

Relevance of Rodent Models of Depression in Clinical Practice: Can We Overcome the Obstacles in Translational Neuropsychiatry?

The diagnosis of a mental disorder generally depends on clinical observations and phenomenological symptoms reported by the patient. The definition of a given diagnosis is criteria based and relies on the ability to accurately interpret subjective symptoms and complex behavior. This type of diagnosis comprises a challenge to translate to reliable animal models, and these translational uncertainties hamper the development of new treatments. In this review, we will discuss how depressive-like behavior can be induced in rodents, and the relationship between these models and depression in humans. Specifically, we suggest similarities between triggers of depressive-like behavior in animal models and human conditions known to increase the risk of depression, for example exhaustion and bullying. Although we acknowledge the potential problems in comparing animal findings to human conditions, such comparisons are useful for understanding the complexity of depression, and we highlight the need to develop clinical diagnoses and animal models in parallel to overcome translational uncertainties.

How to measure glucocorticoid receptor's sensitivity in patients with stress-related psychiatric disorders

Stress is a state of derailed homeostasis and a main environmental risk factor for psychiatric diseases. Chronic or uncontrollable stress may lead to a dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which is a common feature of stress-related psychiatric disorders. One of the key mechanisms underlying a disturbed HPA axis is an impaired function of the glucocorticoid receptor (GR) with an enhanced or reduced feedback sensitivity for glucocorticoids and subsequently altered concentrations of peripheral cortisol. GR function is regulated by a multiprotein complex including the different expression of the hsp90 co-chaperone FK 506 binding protein 51 (FKBP5) that may be genetically determined or acquired in response to stressful stimuli. Specific patterns of a dysregulation of the HPA axis and GR function are found in different stress-related psychiatric entities e.g. major depression, job-related exhaustion or posttraumatic stress disorder. GR challenge tests like the dexamethasone-suppression test (DST), the dexamethasone-corticotropin-releasing hormone (dex-CRH) test or most recently the analysis of the dexamethasone-induced gene expression are employed to sensitively measure HPA axis activity in these disorders. They provide information for a stratification of phenotypic similar but neurobiological diverse psychiatric disorders. In this review we present a synopsis of GR challenge tests with a focus on the application of the DST, the CRH test and the dex-CRH test as well as the dexamethasone-induced gene expression in stress-related psychiatric entities.

Differential Effects of Inflammatory and Psychosocial Stress on Mood, Hypothalamic-Pituitary-Adrenal Axis, and Inflammation in Remitted Depression

BACKGROUND/AIMS

Major depressive disorder (MDD) is highly recurrent. This may be due to increased stress sensitivity after remission. Both inflammatory and psychosocial stressors are implicated in the pathogenesis of MDD, but the additive or differential effect is unclear.

METHODS

We conducted a single-blind placebo-controlled study to investigate the effects of inflammatory stress (i.e., typhoid vaccination), psychosocial stress (i.e., Trier Social Stress Test [TSST]), or a combination of both in women (25-45 years old) with (partially) remitted recurrent MDD (n = 21) and healthy female controls (n = 18). We evaluated the effect on mood measured by the Profile of Mood States, markers of the hypothalamic-pituitary-adrenal (HPA) axis activity, and inflammatory system activation. The study was performed during 2 testing days, separated by a washout of 7-14 days. In a crossover design, subjects received one of the interventions on one day and placebo on the other.

RESULTS

A lowering of mood was seen in patients (β [95% CI] = -4.79 [-6.82 to -2.75], p < 0.001) only after vaccination, but not after the TSST or the combination; this effect was not observed in controls. Controls experienced a significantly different response on adrenocorticotropic hormone (ACTH) after vaccination, with a general rise in ACTH not observed in patients. In both groups, the TSST activated the HPA axis and suppressed the inflammatory parameters.

CONCLUSIONS

There is a differential effect of inflammatory and psychosocial stress on mood and HPA axis activation in patients with remitted recurrent MDD. This may be an interesting treatment target in MDD.

Mifepristone enhances insulin-stimulated Akt phosphorylation and glucose uptake in skeletal muscle cells

Mifepristone is the only FDA-approved drug for glycaemia control in patients with Cushing's syndrome and type 2 diabetes. Mifepristone also has beneficial effects in animal models of diabetes and patients with antipsychotic treatment-induced obesity. However, the mechanisms through which Mifepristone produces its beneficial effects are not completely elucidated.

PURPOSE

To determine the effects of mifepristone on insulin-stimulated glucose uptake on a model of L6 rat-derived skeletal muscle cells.

RESULTS

Mifepristone enhanced insulin-dependent glucose uptake, GLUT4 translocation to the plasma membrane and Akt Ser⁴⁷³ phosphorylation in L6 myotubes. In addition, mifepristone reduced oxygen consumption and ATP levels and increased AMPK Thr¹⁷² phosphorylation. The knockdown of AMPK prevented the effects of mifepristone on insulin response.

CONCLUSIONS

Mifepristone enhanced insulin-stimulated glucose uptake through a mechanism that involves a decrease in mitochondrial function and AMPK activation in skeletal muscle cells.

Gene expression in blood of children and adolescents: Mediation between childhood maltreatment and major depressive disorder

Investigating major depressive disorder (MDD) in childhood and adolescence can help reveal the relative contributions of genetic and environmental factors to MDD, since early stages of disease have less influence of illness exposure. Thus, we investigated the mRNA expression of 12 genes related to the hypothalamic-pituitary-adrenal (HPA) axis, inflammation, neurodevelopment and neurotransmission in the blood of children and adolescents with MDD and tested whether a history of childhood maltreatment (CM) affects MDD through gene expression. Whole-blood mRNA levels of 12 genes were compared among 20 children and adolescents with MDD diagnosis (MDD group), 49 participants without MDD diagnosis but with high levels of depressive symptoms (DS group), and 61 healthy controls (HC group). The differentially expressed genes were inserted in a mediation model in which CM, MDD, and gene expression were, respectively, the independent variable, outcome, and intermediary variable. NR3C1, TNF, TNFR1 and IL1B were expressed at significantly lower levels in the MDD group than in the other groups. CM history did not exert a significant direct effect on MDD. However, an indirect effect of the aggregate expression of the 4 genes mediated the relationship between CM and MDD. In the largest study investigating gene expression in children with MDD, we demonstrated that NR3C1, TNF, TNFR1 and IL1B expression levels are related to MDD and conjunctly mediate the effect of CM history on the risk of developing MDD. This supports a role of glucocorticoids and inflammation as potential effectors of environmental stress in MDD.

Influence of ABCB1 polymorphisms and serum concentrations on venlafaxine response in patients with major depressive disorder

BACKGROUND

The pharmacokinetics and the pharmacodynamics of antidepressants show large inter-individual variations which result in unpredictable clinical responses.

AIM

The aim of the study was to examine the effect of ABCB1 polymorphisms and the serum concentrations on the efficacy and tolerability of venlafaxine in patients with major depressive disorder (MDD).

METHODS

Fifty-two outpatients who met the Diagnostic and Statistical Manual of Mental Disorders Fourth Edition (DSM-IV) criteria for MDD were recruited for the study. The severity of depression was assessed using the 17-item Hamilton Rating Scale for Depression scale (HDRS₁₇) and tolerability was assessed based on a query regarding side-effects for 6 weeks. The ABCB1 C3435T/A and G2677T/A polymorphisms were genotyped by PCR/RFLP and steady-state serum venlafaxine concentrations were measured by high-performance liquid chromatography.

RESULTS

Patients with the TT genotype for the C3435T and the TT/TA genotype for the G2677T/A polymorphism showed significantly higher frequencies in venlafaxine-induced akathisia. This relationship was not observed for efficacy. As regards serum venlafaxine concentrations, patient groups showed no significant differences in efficacy and tolerability.

CONCLUSION

The results suggest that individuals with the TT-TT/TA genotypes for the C3435T-G2677T/A polymorphisms of ABCB1 may be pre-disposed to a risk of akathisia.

Fluoxetine effects on molecular, cellular and behavioral endophenotypes of depression are driven by the living environment

Selective serotonin reuptake inhibitors (SSRIs) represent the most common treatment for major depression. However, their efficacy is variable and incomplete. In order to elucidate the cause of such incomplete efficacy, we explored the hypothesis positing that SSRIs may not affect mood per se but, by enhancing neural plasticity, render the individual more susceptible to the influence of the environment. Consequently, SSRI administration in a favorable environment promotes a reduction of symptoms, whereas in a stressful environment leads to a worse prognosis. To test such hypothesis, we exposed C57BL/6 mice to chronic stress in order to induce a depression-like phenotype and, subsequently, to fluoxetine treatment (21 days), while being exposed to either an enriched or a stressful condition. We measured the most commonly investigated molecular, cellular and behavioral endophenotypes of depression and SSRI outcome, including depression-like behavior, neurogenesis, brain-derived neurotrophic factor levels, hypothalamic-pituitary-adrenal axis activity and long-term potentiation. Results showed that, in line with our hypothesis, the endophenotypes investigated were affected by the treatment according to the quality of the living environment. In particular, mice treated with fluoxetine in an enriched condition overall improved their depression-like phenotype compared with controls, whereas those treated in a stressful condition showed a distinct worsening. Our findings suggest that the effects of SSRI on the depression- like phenotype is not determined by the drug per se but is induced by the drug and driven by the environment. These findings may be helpful to explain variable effects of SSRI found in clinical practice and to device strategies aimed at enhancing their efficacy by means of controlling environmental conditions.

In search of the HPA axis activity in unipolar depression patients with childhood trauma: Combined cortisol awakening response and dexamethasone suppression test

The aim of the present study was to examine the impact of childhood trauma on HPA axis activity both in depression patients and healthy controls in order to determine the role of HPA axis abnormalities in depression and to find the differences in HPA axis functioning that may lead certain individuals more susceptible to the depressogenic effects of childhood trauma. Eighty subjects aged 18-45 years were recruited into four study groups (n = 18, depression patients with childhood trauma exposures, CTE/MDD; n = 17, depression patients without childhood adversity, non-CTE/MDD; n = 23, healthy persons with childhood trauma, CTE/non-MDD; and n = 22, healthy persons without childhood adversity, non-CTE/non-MDD). Each participant collected salivary samples in the morning at four time points: immediately upon awakening, 30, 45, and 60 min after awakening for the assessment of CAR and underwent a 1 mg-dexamethasone suppression test (DST). Regardless of depression, subjects with CTE exhibited an enhanced CAR and the CAR areas under the curve to ground (AUCg) were associated with their childhood trauma questionnaire (CTQ) physical neglect scores and CTQ total scores. In addition, the CTE/MDD group also showed a highest post-DST cortisol concentration and a decreased glucocorticoid feedback inhibition among four groups of subjects. The present findings suggested that childhood trauma was associated with hyperactivity of HPA axis as measured with CAR, potentially reflecting the vulnerability for developing depression after early life stress exposures. Moreover, dysfunction of the GR-mediated negative feedback control might contribute to the development of depression after CTE.

Early-Life Adversity Interacts with FKBP5 Genotypes: Altered Working Memory and Cardiac Stress Reactivity in the Oklahoma Family Health Patterns Project

Exposure to stress during critical periods of development can have adverse effects on adult health behaviors, and genetic vulnerabilities may enhance these stress effects. We carried out an exploratory examination of psychological, physiological, and behavioral characteristics of 252 healthy young adults for the impact of early-life adversity (ELA) in relation to the G-to-A single nucleotide polymorphism (SNP), rs9296158, of the FKBP5 gene. FKBP5 is a molecular cochaperone that contributes to the functional status of the glucocorticoid receptor (GR) and to the quality of corticosteroid signaling. FKBP5 expression is upregulated by cortisol exposure during stressful episodes, with greater upregulation seen in A-allele carriers. As such, FKBP5 expression and GR function may be environmentally sensitive in A-allele carriers and therefore suitable for the study of gene-by-environment (G × E) interactions. Compared with FKBP5, GG homozygotes (N=118), A-allele carriers (N = 132) without psychiatric morbidity had progressively worse performance on the Stroop color-word task with increasing levels of ELA exposure (Genotype × ELA, F=5.14, P=0.007), indicating a G × E interaction on working memory in early adulthood. In addition, heart rate response to mental stress was diminished overall in AA/AG-allele carriers (F=5.15, P=0.024). Diminished working memory and attenuated autonomic responses to stress are both associated with risk for alcoholism and other substance use disorders. The present data suggest that FKBP5 in the GR pathway may be a point of vulnerability to ELA, as seen in this group of non-traumatized young adults. FKBP5 is accordingly a potential target for more extensive studies of the impact of ELA on health and health behaviors in adulthood.

Alterations in leukocyte transcriptional control pathway activity associated with major depressive disorder and antidepressant treatment

Major depressive disorder (MDD) is associated with a significantly elevated risk of developing serious medical illnesses such as cardiovascular disease, immune impairments, infection, dementia and premature death. Previous work has demonstrated immune dysregulation in subjects with MDD. Using genome-wide transcriptional profiling and promoter-based bioinformatic strategies, we assessed leukocyte transcription factor (TF) activity in leukocytes from 20 unmedicated MDD subjects versus 20 age-, sex- and ethnicity-matched healthy controls, before initiation of antidepressant therapy, and in 17 of the MDD subjects after 8 weeks of sertraline treatment. In leukocytes from unmedicated MDD subjects, bioinformatic analysis of transcription control pathway activity indicated an increased transcriptional activity of cAMP response element-binding/activating TF (CREB/ATF) and increased activity of TFs associated with cellular responses to oxidative stress (nuclear factor erythroid-derived 2-like 2, NFE2l2 or NRF2). Eight weeks of antidepressant therapy was associated with significant reductions in Hamilton Depression Rating Scale scores and reduced activity of NRF2, but not in CREB/ATF activity. Several other transcriptional regulation pathways, including the glucocorticoid receptor (GR), nuclear factor kappa-B cells (NF-κB), early growth response proteins 1-4 (EGR1-4) and interferon-responsive TFs, showed either no significant differences as a function of disease or treatment, or activities that were opposite to those previously hypothesized to be involved in the etiology of MDD or effective treatment. Our results suggest that CREB/ATF and NRF2 signaling may contribute to MDD by activating immune cell transcriptome dynamics that ultimately influence central nervous system (CNS) motivational and affective processes via circulating mediators.

Altered functioning of the HPA axis in depressed postpartum women

BACKGROUND

The present study aimed to evaluate the relationship between the functioning of the hypothalamic-pituitary-adrenal (HPA) axis and major depressive episodes in the remote postpartum period.

METHODS

The sample (mean age, 28.0±5.3 years) consisted of 37 depressed postpartum women (DPP), 42 euthymic postpartum women (EPP) and 25 non-postpartum healthy women (HC). Salivary cortisol samples were collected immediately after awakening and 30min, 3 and 12h later, at approximately the sixth month postpartum (mean, 169.6±60.3 days).

RESULTS

Differences in cortisol levels were observed at awakening (DPP<EPP=HC), at 30min (DPP<EPP<HC), at 3h (DPP=EPP<HC) and at 12h (DPP>EPP=HC). The relative increment in the cortisol awakening response (CARi%) was significantly higher in HC (113.5±94.3) than in EPP (63.1±69.8) and DPP (32.2±49.6). The relative reduction in diurnal variation (DVr%) was lower in DPP (56.5±41.8) than in EPP (75.6±22.4) and HC (75.1±13.0).

LIMITATIONS

The main limitation was cortisol collection on a single day and without measurement at midnight.

CONCLUSIONS

Our findings suggest that the remote postpartum period involves attenuation of HPA axis reactivity; this dysregulation is more pronounced in the presence of DPP, which is associated with a reduction in cortisol diurnal variation. Abnormalities in the neuroendocrine system related to stress processing, present even several months after delivery, can represent vulnerability to mental disorders. Thus, improvements in the mental health care of postpartum women are needed.

Zebrafish models of major depressive disorders

The zebrafish (Danio rerio) has emerged as a model species for translational research in various neuroscience areas, including depressive disorders. Because of their physiological (neuroanatomical, neuroendocrine, neurochemical) and genetic homology to mammals, robust phenotypes, and value in high-throughput genetic and chemical genetic screens, zebrafish are ideal for developing valid experimental models of major depression and discovering novel therapeutics. Behavioral testing approaches, such as approach-avoidance, cognitive, and social paradigms, are available in zebrafish and have utility in identifying depression-like indices in zebrafish in response to physiological, genetic, environmental, and/or psychopharmacological alterations. In addition, the high sensitivity of zebrafish to commonly prescribed psychotropic drugs supports the use of this model as an invaluable tool for pharmacological research and drug screening. This Review outlines the benefits of using the zebrafish model for depression studies and summarizes the current research in this field.

Injustice at work and leukocyte glucocorticoid sensitivity: findings from a cross-sectional study

OBJECTIVE

Organizational justice refers to perceived fairness at the workplace. Low organizational justice has been identified as a major source of distress and a predictor of poor health. Impaired regulation of immunological and inflammatory pathways may, in part, underlie these health effects. The present study investigated the association of organizational justice with leukocyte glucocorticoid sensitivity in vivo.

METHODS

Organizational justice was assessed among 541 male factory workers (mean [standard deviation] age = 46 [9] years) by questionnaire. Cortisol release was measured at three time points before blood collection and summed as the area under the curve. Blood was used to assess leukocyte (white blood cell [WBC] count) subsets (neutrophils [%WBC], lymphocytes [%WBC], and the neutrophil/lymphocyte ratio). Glucocorticoid sensitivity was operationalized as the correlation between cortisol release and these hematologic parameters. Associations were adjusted for demographics, work characteristics, and life-style variables.

RESULTS

A dose-response relationship between organizational justice and glucocorticoid sensitivity was found. Cortisol and hematologic parameters showed the expected significant association among individuals reporting high (all β values ≥ |.26|; all p values ≤.001) or medium organizational justice (all β values ≥ |.15|; all p values ≤.050), but not among those reporting low organizational justice (all β values ≤ |.04|; all p values > .10). These regression slopes differed significantly between organizational justice groups (p values for interaction < .050).

CONCLUSIONS

Low justice at work is associated with an impaired ability of endogenous cortisol to regulate leukocyte distribution in vivo. These findings identify a novel biological pathway by which organizational justice may affect health.

Stress induces endotoxemia and low-grade inflammation by increasing barrier permeability

Chronic non-communicable diseases (NCDs) are the leading causes of work absence, disability, and mortality worldwide. Most of these diseases are associated with low-grade inflammation. Here, we hypothesize that stresses (defined as homeostatic disturbances) can induce low-grade inflammation by increasing the availability of water, sodium, and energy-rich substances to meet the increased metabolic demand induced by the stressor. One way of triggering low-grade inflammation is by increasing intestinal barrier permeability through activation of various components of the stress system. Although beneficial to meet the demands necessary during stress, increased intestinal barrier permeability also raises the possibility of the translocation of bacteria and their toxins across the intestinal lumen into the blood circulation. In combination with modern life-style factors, the increase in bacteria/bacterial toxin translocation arising from a more permeable intestinal wall causes a low-grade inflammatory state. We support this hypothesis with numerous studies finding associations with NCDs and markers of endotoxemia, suggesting that this process plays a pivotal and perhaps even a causal role in the development of low-grade inflammation and its related diseases.

Steroid regulation of T cell function appears unaltered in borderline personality disorder

Borderline personality disorder (BPD) is characterized by instability of interpersonal relationships and affection, impulsivity, and cognitive disruptions. Increasing evidence suggests hypothalamic-pituitary-adrenal (HPA) axis alterations in BPD. Changed glucocorticoid sensitivity of peripheral blood mononuclear cells is known in mood and posttraumatic stress disorders, representing frequent comorbidities in BPD. However, to the authors' knowledge, in BPD glucocorticoid sensitivity at the receptor level remains unexplored. Sixteen age-matched female BPD patients were compared to sixteen female healthy controls. In vitro steroid sensitivity of T cell proliferation was tested using aldosterone, dexamethasone, and hydrocortisone. Steroid sensitivity of BPD patients and healthy controls appeared comparable. Psychiatric comorbidities such as major depressive disorder or posttraumatic stress disorder and early life stress seemed to have had no influence on steroid sensitivity parameters. The data suggest unaltered GC sensitivity of T cell function in BPD.

FKBP5 genotype-dependent DNA methylation and mRNA regulation after psychosocial stress in remitted depression and healthy controls

BACKGROUND

Polymorphisms in the FK506 binding protein 5 (FKBP5) gene have been shown to influence glucocorticoid receptor sensitivity, stress response regulation, and depression risk in traumatized subjects, with most consistent findings reported for the functional variant rs1360780. In the present study, we investigated whether the FKBP5 polymorphism rs1360780 and lifetime history of major depression are associated with DNA methylation and FKBP5 gene expression after psychosocial stress.

METHODS

A total of 116 individuals with a positive (n = 61) and negative (n = 55) lifetime history of major depression participated in the Trier Social Stress Test. We assessed plasma cortisol concentrations, FKBP5 mRNA expression, and CpG methylation of FKBP5 intron 7 in peripheral blood cells.

RESULTS

Genotype-dependent plasma cortisol response to psychosocial stress exposure was observed in healthy controls, with the highest and longest-lasting cortisol increase in subjects with the TT genotype of the FKBP5 polymorphism rs1360780, and healthy controls carrying the T risk allele responded with a blunted FKBP5 mRNA expression after psychosocial stress. No genotype effects could be found in remitted depression.

CONCLUSIONS

The FKBP5 rs1360780 polymorphism is associated with plasma cortisol and FKBP5 mRNA expression after psychosocial stress in healthy controls but not in remitted depression. Preliminary results of the DNA methylation analysis suggest that epigenetic modifications could be involved.

Hormones, stress, and cognition: The effects of glucocorticoids and oxytocin on memory

Hormones have nuanced effects on learning and memory processes. The degree and direction of the effect (e.g., is memory impaired or enhanced?) depends on the dose, type and stage of memory, and type of material being learned, among other factors. This review will focus on two specific topics within the realm of effects of hormones on memory: (1) How glucocorticoids (the output hormones of the hypothalamic-pituitary-adrenal axis) affect long-term memory consolidation, retrieval, and working memory, with a focus on neural mechanisms and effects of emotion; and (2) How oxytocin affects memory, with emphasis on a speculative hypothesis that oxytocin might exert its myriad effects on human social cognition and behavior via impacts on more general cognitive processes. Oxytocin-glucocorticoid interactions will be briefly addressed. These effects of hormones on memory will also be considered from an evolutionary perspective.

ABCB1 C3435T polymorphism is associated with susceptibility to major depression, but not with a clinical response to citalopram in a Turkish population

BACKGROUND

The ATP-binding cassette sub-family B member 1 (ABCB1) gene, which encodes the p-glycoprotein at the blood-brain barrier, is investigated for patients' susceptibility to major depressive disorder (MDD) and their therapeutic response to antidepressants. However, there is an inconsistency between the studies of different ethnic groups. The current study aimed to determine the potential correlations of the ABCB1 gene C3435T polymorphism with the susceptibility to MDD and the therapeutic response to citalopram in a Turkish population.

METHODS

Fifty-four patients with MDD who received citalopram and 70 controls from the Turkish population were genotyped for ABCB1 C3435T polymorphism. To assess the therapeutic response to citalopram, all patients were rated baseline, first, second, fourth and sixth weeks according to the 17-item Hamilton Rating Scale for Depression (HAMD-17).

RESULTS

There was a significant correlation between the patient and control groups for ABCB1 C3435T polymorphism. Distribution of CC genotype and C allele frequency were higher in the patients than in the control group (p = 0.006, p = 0.020, respectively). However, no correlation between ABCB1 C3435T polymorphism and a therapeutic response to citalopram was observed.

CONCLUSION

Our results suggested that C3435T polymorphism in the ABCB1 gene may be an indicator of the susceptibility to major depression, without a likely treatment response to citalopram in a Turkish population. These findings should be replicated in studies on larger patient groups with different ethnicities.

Are there meaningful biomarkers of treatment response for depression?

During the past decades, the prevalence of affective disorders has been on the rise globally, with only one out of three patients achieving remission in acute treatment with antidepressants. The identification of physiological markers that predict treatment course proves useful in increasing therapeutic success. On the basis of well-documented, recent findings in depression research, we highlight and discuss the most promising biomarkers for antidepressant therapy response. These include genetic variants and gene expression profiles, proteomic and metabolomic markers, neuroendocrine function tests, electrophysiology and imaging techniques. Ultimately, this review proposes an integrative use of biomarkers for antidepressant treatment outcome.

Mechanistic insights into corticosteroids in multiple sclerosis: war horse or chameleon?

OBJECTIVES

Relapse management is a crucial component of multiple sclerosis (MS) care. High-dose corticosteroids (CSs) are used to dampen inflammation, which is thought to hasten the recovery of MS relapse. A diversity of mechanisms drive the heterogeneous clinical response to exogenous CSs in patients with MS. Preclinical research is beginning to provide important insights into how CSs work, both in terms of intended and unintended effects. In this article we discuss cellular, systemic, and clinical characteristics that might contribute to intended and unintended CS effects when utilizing supraphysiological doses in clinical practice. The goal of this article is to consider recent insights about CS mechanisms of action in the context of MS.

METHODS

We reviewed relevant preclinical and clinical studies on the desirable and undesirable effects of high-dose corticosteroids used in MS care.

RESULTS

Preclinical studies reviewed suggest that corticosteroids may act in unpredictable ways in the context of autoimmune conditions. The precise timing, dosage, duration, cellular exposure, and background CS milieu likely contribute to their clinical heterogeneity.

CONCLUSION

It is difficult to predict when patients will respond favorably to CSs, both in terms of therapeutic response and tolerability profile. There are specific cellular, systemic, and clinical characteristics that might merit further consideration when utilizing CSs in clinical practice, and these should be explored in a translational setting.

Mood and metabolic consequences of sleep deprivation as a potential endophenotype' in bipolar disorder

It has been commonly recognized that circadian rhythm and sleep/wake cycle are causally involved in bipolar disorder. There has been a paucity of systematic research considering the relations between sleep and mood states in bipolar disorder. The current study examines the possible influences of sleep deprivation on mood states and endocrine functions among first-degree relatives of patients with bipolar disorder and healthy controls. Blood samples were taken at two time points in the consecutive mornings at predeprivation and postdeprivation periods. Participants simultaneously completed the Profiles of Mood States at two time points after giving blood samples. Plasma T3 and TSH levels increased after total sleep deprivation in both groups. Sleep deprivation induced TSH levels were reversely associated with depression-dejection among healthy controls. A paradoxical effect was detected for only the first-degree relatives of the patients that changes in plasma cortisol levels negatively linked to depression-dejection and anger-hostility scores after total sleep deprivation. Plasma DHEA levels became correlated with vigor-activity scores after sleep deprivation among first-degree relatives of bipolar patients. On the contrary, significant associations of depression-dejection, anger-hostility, and confusion-bewilderment with the baseline plasma DHEA levels became statistically trivial in the postdeprivation period. Findings suggested that first-degree relatives of patients with bipolar disorder had completely distinct characteristics with respect to sleep deprivation induced responses in terms of associations between endocrine functions and mood states as compared to individuals whose relatives had no psychiatric problems. Considering the relationships between endocrine functions and mood states among relatives of the patients, it appears like sleep deprivation changes the receptor sensitivity which probably plays a pivotal role on mood outcomes among the first-degree relatives of patients with bipolar disorder.

Neural control of chronic stress adaptation

Stress initiates adaptive processes that allow the organism to physiologically cope with prolonged or intermittent exposure to real or perceived threats. A major component of this response is repeated activation of glucocorticoid secretion by the hypothalamo-pituitary-adrenocortical (HPA) axis, which promotes redistribution of energy in a wide range of organ systems, including the brain. Prolonged or cumulative increases in glucocorticoid secretion can reduce benefits afforded by enhanced stress reactivity and eventually become maladaptive. The long-term impact of stress is kept in check by the process of habituation, which reduces HPA axis responses upon repeated exposure to homotypic stressors and likely limits deleterious actions of prolonged glucocorticoid secretion. Habituation is regulated by limbic stress-regulatory sites, and is at least in part glucocorticoid feedback-dependent. Chronic stress also sensitizes reactivity to new stimuli. While sensitization may be important in maintaining response flexibility in response to new threats, it may also add to the cumulative impact of glucocorticoids on the brain and body. Finally, unpredictable or severe stress exposure may cause long-term and lasting dysregulation of the HPA axis, likely due to altered limbic control of stress effector pathways. Stress-related disorders, such as depression and PTSD, are accompanied by glucocorticoid imbalances and structural/ functional alterations in limbic circuits that resemble those seen following chronic stress, suggesting that inappropriate processing of stressful information may be part of the pathological process.

The neuroprogressive nature of major depressive disorder: pathways to disease evolution and resistance, and therapeutic implications

In some patients with major depressive disorder (MDD), individual illness characteristics appear consistent with those of a neuroprogressive illness. Features of neuroprogression include poorer symptomatic, treatment and functional outcomes in patients with earlier disease onset and increased number and length of depressive episodes. In such patients, longer and more frequent depressive episodes appear to increase vulnerability for further episodes, precipitating an accelerating and progressive illness course leading to functional decline. Evidence from clinical, biochemical and neuroimaging studies appear to support this model and are informing novel therapeutic approaches. This paper reviews current knowledge of the neuroprogressive processes that may occur in MDD, including structural brain consequences and potential molecular mechanisms including the role of neurotransmitter systems, inflammatory, oxidative and nitrosative stress pathways, neurotrophins and regulation of neurogenesis, cortisol and the hypothalamic-pituitary-adrenal axis modulation, mitochondrial dysfunction and epigenetic and dietary influences. Evidence-based novel treatments informed by this knowledge are discussed.

The neurobiology of suicide - A Review of post-mortem studies

The neurobiology of suicidal behaviour, which constitutes one of the most serious problems both in psychiatry and general medical practice, still remains to a large degree unclear. As a result, scientists constantly look for new opportunities of explaining the causes underlying suicidality. In order to elucidate the biological changes occurring in the brains of the suicide victims, studies based on post-mortem brain tissue samples are increasingly being used. These studies employ different research methods to provide an insight into abnormalities in brain functioning on various levels, including gene and protein expression, neuroplasticity and neurotransmission, as well as many other areas. The aim of this paper to summarize the available data on the post-mortem studies, to provide an overview of main research directions and the most up-to-date findings, and to indicate the possibilities of further research in this field.

Biomarkers in bipolar disorder: a positional paper from the International Society for Bipolar Disorders Biomarkers Task Force

Although the etiology of bipolar disorder remains uncertain, multiple studies examining neuroimaging, peripheral markers and genetics have provided important insights into the pathophysiologic processes underlying bipolar disorder. Neuroimaging studies have consistently demonstrated loss of gray matter, as well as altered activation of subcortical, anterior temporal and ventral prefrontal regions in response to emotional stimuli in bipolar disorder. Genetics studies have identified several potential candidate genes associated with increased risk for developing bipolar disorder that involve circadian rhythm, neuronal development and calcium metabolism. Notably, several groups have found decreased levels of neurotrophic factors and increased pro-inflammatory cytokines and oxidative stress markers. Together these findings provide the background for the identification of potential biomarkers for vulnerability, disease expression and to help understand the course of illness and treatment response. In other areas of medicine, validated biomarkers now inform clinical decision-making. Although the findings reviewed herein hold promise, further research involving large collaborative studies is needed to validate these potential biomarkers prior to employing them for clinical purposes. Therefore, in this positional paper from the ISBD-BIONET (biomarkers network from the International Society for Bipolar Disorders), we will discuss our view of biomarkers for these three areas: neuroimaging, peripheral measurements and genetics; and conclude the paper with our position for the next steps in the search for biomarkers for bipolar disorder.

Estradiol stimulates an anti-translocation expression pattern of glucocorticoid co-regulators in a hippocampal cell model

A consistent clinical finding in patients with major depressive disorder (MDD) is hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis, the system in the body that facilitates the response to stress. It has been suggested that alterations in glucocorticoid receptor (GR)-mediated feedback prolong activation of the HPA axis, leading to the dysfunction observed in MDD. Additionally, the risk for developing MDD is heightened by several risk factors, namely gender, genetics and early life stress. Previous studies have demonstrated that GR translocation is sexually dimorphic and this difference may be facilitated by differential expression of GR co-regulators. The purpose of this study was to determine the extent to which ovarian hormones alter expression of GR and its co-regulators, Fkbp5 and Ppid, in HT-22 hippocampal neurons. The impact of corticosterone (cort), estradiol (E2), and progesterone (P4) treatments on the expression of the genes Nr3c1, Ppid, and Fkbp5 was assessed in HT-22 hippocampal neurons. Treatment of cells with increasing doses of cort increased the expression of Fkbp5, an effect that was potentiated by E2. Exposure of HT-22 cells to E2 decreased the expression of Ppid and simultaneous exposure to E2 and P4 had combinatory effects on Ppid expression. The effects of E2 on Ppid extend previous work which demonstrated that serum E2 concentrations correlate with hippocampal Ppid expression in female rats. The results presented here illustrate that E2 generates an anti-translocation pattern of GR co-regulators in hippocampal cells.

Salivary alpha-amylase and cortisol responsiveness following electrically stimulated physical stress in bipolar disorder patients

BACKGROUND

Bipolar disorder (BP) is often associated with a change in hypothalamus- pituitary-adrenal axis function change due to chronic stress. Salivary α-amylase (sAA) levels increase in response to psychosocial stress and thus function as a marker of sympathoadrenal medullary system activity. However, sAA has been studied less often than salivary cortisol in BP patients.

METHOD

We measured Profile of Mood States and State-Trait Anxiety Inventory scores, heart rate variability, and salivary cortisol levels during electrical stimulation stress in 25 BP patients and 22 healthy volunteers.

RESULTS

Tension-anxiety, depression-dejection, anger-hostility, fatigue, and confusion scores in BP patients significantly increased compared with those of the healthy controls. In contrast, the vigor scores of BP patients significantly decreased compared with those of the healthy controls. Significant difference in the sAA levels was observed between BP patients and healthy controls. sAA of female patients was significantly higher than that of female healthy controls, and sAA in male patients tended to be higher than that of male healthy controls. No difference in salivary cortisol was observed between BP patients and the healthy controls. Only three time points were measured before and after the electrical stimulation stress. Furthermore, sAA secretion by BP patients increased before and after electrical stimulation.

CONCLUSION

These preliminary results suggest that sAA may be a useful biological marker for BP patients.

Ex vivo stimulation of whole blood as a means to determine glucocorticoid sensitivity

PURPOSE

Glucocorticoids are commonly prescribed to treat a number of diseases including the majority of inflammatory diseases. Despite considerable interpersonal variability in response to glucocorticoids, an insensitivity rate of about 30%, and the risk of adverse side effects of glucocorticoid therapy, currently no assay is performed to determine sensitivity.

PATIENTS AND METHODS

Here we propose a whole blood ex vivo stimulation assay to interrogate known glucocorticoid receptor (GR) up- and downregulated genes to indicate glucocorticoid sensitivity. We have chosen to employ real-time PCR in order to provide a relatively fast and inexpensive assay.

RESULTS

We show that the GR-regulated genes, GILZ and FKBP51, are upregulated in whole blood by treatment with dexamethasone and that LPS-induction of cytokines (IL-6 and TNFα) are repressed by dexamethasone in a dose responsive manner. There is considerable interpersonal variability in the maximum induction of these genes but little variation in the EC(50) and IC(50) concentrations. The regulation of the GR-induced genes differs throughout the day whereas the suppression of LPS-induced cytokines is not as sensitive to time of day.

CONCLUSION

In all, this assay would provide a method to determine glucocorticoid receptor responsiveness in whole blood.

Biological indicators of illness risk in offspring of bipolar parents: targeting the hypothalamic-pituitary-adrenal axis and immune system

AIM

The study aims to provide a selective review of the literature pertaining to the hypothalamic-pituitary-adrenal (HPA) axis and immune abnormalities as informative biological indicators of vulnerability in bipolar disorder (BD).

METHOD

We summarize key findings relating to HPA axis and immunological abnormalities in bipolar patients and their high-risk offspring. Findings derive from a review of selected original papers published in the literature, and supplemented by papers identified through bibliography review. Neurobiological findings are discussed in the context of emergent BD in those at genetic risk and synthesized into a neurodevelopmental model of illness onset and progression.

RESULTS

BD is associated with a number of genetic and possibly epigenetic abnormalities associated with neurotransmitter, hormonal and immunologically mediated neurobiological pathways. Data from clinical and high-risk studies implicate HPA axis and immune system abnormalities, which may represent inherited vulnerabilities important for the transition to illness onset. Post-mortem and clinical studies implicate intracellular signal transduction processes and disturbance in energy metabolism associated with established BD. Specifically, long-standing maladaptive alterations such as changes in neuronal systems may be mediated through changes in intracellular signalling pathways, oxidative stress, cellular energy metabolism and apoptosis associated with substantial burden of illness.

CONCLUSIONS

Prospective longitudinal studies of endophenotypes and biomarkers such as HPA axis and immune abnormalities in high-risk offspring will be helpful to understand genetically mediated biological pathways associated with illness onset and progression. A clinical staging model describing emergent illness in those at genetic risk should facilitate this line of investigation.

Regulation of mRNA expression encoding chaperone and co-chaperone proteins of the glucocorticoid receptor in peripheral blood: association with depressive symptoms during pregnancy

BACKGROUND

Major depressive disorder during pregnancy associates with potentially detrimental consequences for mother and child. The current study examined peripheral blood gene expression as a potential biomarker for prenatal depressive symptoms.

METHOD

Maternal RNA from whole blood, plasma and the Beck Depression Inventory were collected longitudinally from preconception through the third trimester of pregnancy in 106 women with a lifetime history of mood or anxiety disorders. The expression of 16 genes in whole blood involved in glucorticoid receptor (GR) signaling was assessed using real-time polymerase chain reaction. In parallel, plasma concentrations of progesterone, estradiol and cortisol were measured. Finally, we assessed ex vivo GR sensitivity in peripheral blood cells from a subset of 29 women.

RESULTS

mRNA expression of a number of GR-complex regulating genes was up-regulated over pregnancy. Women with depressive symptoms showed significantly smaller increases in mRNA expression of four of these genes - FKBP5, BAG1, NCOA1 and PPID. Ex vivo stimulation assays showed that GR sensitivity diminished with progression of pregnancy and increasing maternal depressive symptoms. Plasma concentrations of gonadal steroids and cortisol did not differ over pregnancy between women with and without clinically relevant depressive symptoms.

CONCLUSIONS

The presence of prenatal depressive symptoms appears to be associated with altered regulation of GR sensitivity. Peripheral expression of GR co-chaperone genes may serve as a biomarker for risk of developing depressive symptoms during pregnancy. The presence of such biomarkers, if confirmed, could be utilized in treatment planning for women with a psychiatric history.

The effects of a psychoneuroimmunology (PNI) based lifestyle intervention in modifying the progression of depression in clinically depressed adults

OBJECTIVE

Uncontrolled stress can lead to poorly controlled upsurges of cortisol and deregulation of the hypothalamus pituitary-adrenal axis (HPA), thereby leading to major depression. Psychoneuroimmunology (PNI) is the area of medicine dealing with the bidirectional pathways connecting the influences of brain, neuroendocrine, and immune system. Individual PNI-based lifestyle interventions such as humor and guided imagery have been shown to modulate the stress response. However, researchers have not examined the composite effect of a PNI-based lifestyle intervention among clinically depressed adults.

METHOD

This randomized interventional study examined the composite effect(s) of a PNI-based lifestyle intervention: progressive muscle relaxation, spiritual guided imagery, and humor as an adjunct therapy to modifying the progression of depression. Forty-one participants recruited from doctors' offices in San Bernardino and Riverside counties in Southern California, were randomized into two groups: treatment (N = 20) and control (N = 21). For a period of three weeks, participants in the treatment group listened to a 12-minute progressive muscle relaxation and spiritual guided imagery CD daily and watched 10 minutes of humorous DVDs. Participants in both groups were also receiving cognitive behavioral therapy and pharmacotherapy.

RESULTS

Depression, spirituality, humor, and stress were assessed at baseline and week 3. Depression significantly decreased from severe to mild from baseline to week 3 in the treatment group. Spirituality significantly increased in the treatment group but remained unchanged in the controls.

CONCLUSIONS

These findings offer depressed patients alternative approaches to preventing complications and managing their illness in the context of whole-person lifestyle optimization and integration of mind-body-spirit.

Acute and chronic stress induced changes in sensitivity of peripheral inflammatory pathways to the signals of multiple stress systems --2011 Curt Richter Award Winner

Exposure to psychosocial stress has been associated with increasing rates of morbidity in humans and in animal models, but the underlying mechanisms are not completely understood. Major stress responsive systems, such as the hypothalamus-pituitary adrenal (HPA) axis and the autonomic nervous system (ANS) are under investigation as underlying pathways, but although acute stress reliably activates these systems, findings of long-term alternations in baseline activity are inconsistent at present. Emerging evidence suggests that stress-related changes in the sensitivity of target systems toward glucocorticoid (GC) regulation, i.e. development of GC resistance, might help explain inflammatory disinhibition and development of disease related to inflammation. More recent findings further show that the autonomic nervous system might play an important role in the regulatory control of the inflammatory cascade. The major argument put forward in this manuscript is that target tissues for stress system modulation, such as the inflammatory cascade, vary in their ability to respond to stress system signaling, and that assessing alterations in this stress signal sensitivity which can be caused by stress or disease processes, might be necessary to understand and explain stress effects on health. This review focuses on the inflammatory system in particular, because anti-inflammatory effects of most stress systems have been documented, but the general assumption might have to be generalized to other target systems. The main conclusion to be made is that reduction in glucocorticoid sensitivity of target tissues is the most consistent finding at present, and that assessing such changes in glucocorticoid sensitivity might be necessary to understand many stress-related changes in physiology.

Childhood adversity and epigenetic modulation of the leukocyte glucocorticoid receptor: preliminary findings in healthy adults

Background

A history of early adverse experiences is an important risk factor for adult psychopathology. Changes in stress sensitivity and functioning of the hypothalamic-pituitary-adrenal (HPA) axis may underlie the association between stress and risk for psychiatric disorders. Preclinical work in rodents has linked low levels of maternal care to increased methylation of the promoter region of the glucocorticoid receptor (GR) gene, as well as to exaggerated hormonal and behavioral responses to stress. Recent studies have begun to examine whether early-life stress leads to epigenetic modifications of the GR gene in humans.

Methods

We examined the degree of methylation of a region of the promoter of the human GR gene (NR3C1) in leukocyte DNA from 99 healthy adults. Participants reported on their childhood experiences of parental behavior, parental death or desertion, and childhood maltreatment. On a separate day, participants completed the dexamethasone/corticotropin-releasing hormone (Dex/CRH) test, a standardized neuroendocrine challenge test.

Results

Disruption or lack of adequate nurturing, as measured by parental loss, childhood maltreatment, and parental care, was associated with increased NR3C1 promoter methylation (p<.05). In addition, NR3C1 promoter methylation was linked to attenuated cortisol responses to the Dex/CRH test (p<.05).

Conclusions

These findings suggest that childhood maltreatment or adversity may lead to epigenetic modifications of the human GR gene. Alterations in methylation of this gene could underlie the associations between childhood adversity, alterations in stress reactivity, and risk for psychopathology.

Psychoneuroimmunology meets neuropsychopharmacology: translational implications of the impact of inflammation on behavior

The potential contribution of chronic inflammation to the development of neuropsychiatric disorders such as major depression has received increasing attention. Elevated biomarkers of inflammation, including inflammatory cytokines and acute-phase proteins, have been found in depressed patients, and administration of inflammatory stimuli has been associated with the development of depressive symptoms. Data also have demonstrated that inflammatory cytokines can interact with multiple pathways known to be involved in the development of depression, including monoamine metabolism, neuroendocrine function, synaptic plasticity, and neurocircuits relevant to mood regulation. Further understanding of mechanisms by which cytokines alter behavior have revealed a host of pharmacologic targets that may be unique to the impact of inflammation on behavior and may be especially relevant to the treatment and prevention of depression in patients with evidence of increased inflammation. Such targets include the inflammatory signaling pathways cyclooxygenase, p38 mitogen-activated protein kinase, and nuclear factor-κB, as well as the metabolic enzyme, indoleamine-2,3-dioxygenase, which breaks down tryptophan into kynurenine. Other targets include the cytokines themselves in addition to chemokines, which attract inflammatory cells from the periphery to the brain. Psychosocial stress, diet, obesity, a leaky gut, and an imbalance between regulatory and pro-inflammatory T cells also contribute to inflammation and may serve as a focus for preventative strategies relevant to both the development of depression and its recurrence. Taken together, identification of mechanisms by which cytokines influence behavior may reveal a panoply of personalized treatment options that target the unique contributions of the immune system to depression.