The Role of Proopiomelanocortin and α-Melanocyte-Stimulating Hormone in the Metabolic Syndrome in Psychiatric Disorders: A Narrative Mini-Review

The missing hallmark of health: psychosocial adaptation

The eight biological hallmarks of health that we initially postulated (Cell. 2021 Jan 7;184(1):33-63) include features of spatial compartmentalization (integrity of barriers, containment of local perturbations), maintenance of homeostasis over time (recycling & turnover, integration of circuitries, rhythmic oscillations) and an array of adequate responses to stress (homeostatic resilience, hormetic regulation, repair & regeneration). These hallmarks affect all eight somatic strata of the human body (molecules, organelles, cells, supracellular units, organs, organ systems, systemic circuitries and meta-organism). Here we postulate that mental and socioeconomic factors must be added to this 8×8 matrix as an additional hallmark of health ("psychosocial adaptation") and as an additional stratum ("psychosocial interactions"), hence building a 9×9 matrix. Potentially, perturbation of each of the somatic hallmarks and strata affects psychosocial factors and vice versa. Finally, we discuss the (patho)physiological bases of these interactions and their implications for mental health improvement.

Alterations of serum neuropeptide levels and their relationship to cognitive impairment and psychopathology in male patients with chronic schizophrenia

Serum neuropeptide levels may be linked to schizophrenia (SCZ) pathogenesis. This study aims to examine the relation between five serum neuropeptide levels and the cognition of patients with treatment-resistant schizophrenia (TRS), chronic stable schizophrenia (CSS), and in healthy controls (HC). Three groups were assessed: 29 TRS and 48 CSS patients who were hospitalized in regional psychiatric hospitals, and 53 HC. After the above participants were enrolled, we examined the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the blood serum levels of α-melanocyte stimulating hormone (α-MSH), β-endorphin (BE), neurotensin (NT), oxytocin (OT) and substance.P (S.P). Psychiatric symptoms in patients with SCZ were assessed with the Positive and Negative Syndrome Scale. SCZ patients performed worse than HC in total score and all subscales of the RBANS. The levels of the above five serum neuropeptides were significantly higher in SCZ than in HC. The levels of OT and S.P were significantly higher in CSS than in TRS patients. The α-MSH levels in TRS patients were significantly and negatively correlated with the language scores of RBANS. However, the BE and NT levels in CSS patients were significantly and positively correlated with the visuospatial/constructional scores of RBANS. Moreover, the interaction effect of NT and BE levels was positively associated with the visuospatial/constructional scores of RBANS. Therefore, abnormally increased serum neuropeptide levels may be associated with the physiology of SCZ, and may cause cognitive impairment and psychiatric symptoms, especially in patients with TRS.

HFD-exacerbated Metabolic Side Effects of Olanzapine Are Suppressed by ER Stress Inhibitor

OBJECTIVE

Numerous schizophrenic patients are suffering from obesity primarily attributed to antipsychotic medication and poor dietary habits. This study investigated the progressive deterioration of olanzapine-induced metabolic disorders in the presence of a high-fat diet (HFD) and explored the involvement of endoplasmic reticulum (ER) stress.

METHODS

Female Sprague-Dawley rats fed on a standard chow diet or HFD were treated with olanzapine (3 mg/kg/day) and the ER stress inhibitor 4-phenylbutyric acid (4-PBA, 1 and 0.5 g/kg/day) for 8 days. Changes in body weight, food intake, and plasma lipids were assessed. Hepatic fat accumulation was evaluated using oil red O staining. Western blotting and immunofluorescence assays were employed to examine the expression of ER stress markers, NOD-like receptor pyrin domain-containing protein 3 (NLRP3), and proopiomelanocortin (POMC) in the hypothalamus or liver.

RESULTS

Compared to olanzapine alone, olanzapine+HFD induced greater weight gain, increased hyperlipidemia, and enhanced hepatic fat accumulation (P<0.05). Co-treatment with 4-PBA exhibited a dose-dependent inhibition of these effects (P<0.05). Further mechanistic investigations revealed that olanzapine alone activated ER stress, upregulated NLRP3 expression in the hypothalamus and liver, and downregulated hypothalamic POMC expression. The HFD exacerbated these effects by 50%-100%. Moreover, co-administration of 4-PBA dose-dependently attenuated the olanzapine+HFD-induced alterations in ER stress, NLRP3, and POMC expression in the hypothalamus and liver (P<0.05).

CONCLUSION

HFD worsened olanzapine-induced weight gain and lipid metabolic disorders, possibly through ER stress-POMC and ER stress-NLRP3 signaling. ER stress inhibitors could be effective in preventing olanzapine+HFD-induced metabolic disorders.

Decreased plasma neuropeptides in first-episode schizophrenia, bipolar disorder, major depressive disorder: associations with clinical symptoms and cognitive function

Background

There is an urgent need to identify differentiating and disease-monitoring biomarkers of schizophrenia, bipolar disorders (BD), and major depressive disorders (MDD) to improve treatment and management.

Methods

We recruited 54 first-episode schizophrenia (FES) patients, 52 BD patients, 35 MDD patients, and 54 healthy controls from inpatient and outpatient clinics. α-Melanocyte Stimulating Hormone (α-MSH), β-endorphin, neurotensin, orexin-A, oxytocin, and substance P were investigated using quantitative multiplex assay method. Psychotic symptoms were measured using the Brief Psychiatric Rating Scale (BPRS) and Positive and Negative Syndrome Scale (PANSS), manic symptoms using the Young Mania Rating Scale (YMRS), and depressive symptoms using 17 item-Hamilton Depression Rating Scale (HAMD). We additionally measured cognitive function by using a battery of tests given to all participants.

Results

α-MSH, neurotensin, orexin-A, oxytocin, and substance P were decreased in the three patient groups compared with controls. Neurotensin outperformed all biomarkers in differentiating patient groups from controls. There were no significant differences for 6 neuropeptides in their ability to differentiate between the three patient groups. Higher neurotensin was associated with better executive function across the entire sample. Lower oxytocin and higher substance p were associated with more psychotic symptoms in FES and BD groups. β-endorphin was associated with early morning wakening symptom in all three patient groups.

Conclusion

Our research shows decreased circulating neuropeptides have the potential to differentiate severe mental illnesses from controls. These neuropeptides are promising treatment targets for improving clinical symptoms and cognitive function in FES, BD, and MDD.

The Role of Adipokines in Health and Disease

Adipokines are cell-signaling proteins secreted by adipose tissue that has been related to a low-grade state of inflammation and different pathologies. The present review aims to analyze the role of adipokines in health and disease in order to understand the important functions and effects of these cytokines. For this aim, the present review delves into the type of adipocytes and the cytokines produced, as well as their functions; the relations of adipokines in inflammation and different diseases such as cardiovascular, atherosclerosis, mental diseases, metabolic disorders, cancer, and eating behaviors; and finally, the role of microbiota, nutrition, and physical activity in adipokines is discussed. This information would allow for a better understanding of these important cytokines and their effects on body organisms.

Plasma neuropeptide levels in patients with schizophrenia, bipolar disorder, or major depressive disorder and healthy controls: A multiplex immunoassay study

AIM

We aimed to compare neuropeptide levels between patients with major psychiatric disorders and healthy controls and examine their association with symptoms and cognitive function.

METHODS

The participants were 149 patients with schizophrenia, 115 patients with bipolar disorder (BD), 186 unremitted patients with major depressive disorder (MDD), and 350 healthy controls. Psychiatric (schizophrenic, manic, and depressive) symptoms, sleep state, and cognitive (premorbid intelligence quotient, general cognitive, and memory) functions were evaluated. A multiplex immunoassay kit was used to measure cerebrospinal fluid (CSF) and plasma α-melanocyte-stimulating hormone (MSH), β-endorphin, neurotensin, oxytocin, and substance P levels.

RESULTS

The verification assay revealed that CSF α-MSH, β-endorphin, neurotensin, oxytocin, and substance P levels were too low to be reliably measured, while plasma α-MSH, β-endorphin, neurotensin, oxytocin, and substance P levels could be successfully measured. Plasma α-MSH, β-endorphin, neurotensin, oxytocin, and substance P levels were not significantly different between patients with schizophrenia, BD, or MDD and healthy controls. Plasma α-MSH, β-endorphin, neurotensin, oxytocin, and substance P levels were not significantly correlated with psychiatric symptom scores in patients with schizophrenia, BD, or MDD and cognitive function scores in patients or healthy controls.

CONCLUSION

Our data suggest that plasma neuropeptide levels do not elucidate the involvement of neuropeptides in the pathology of schizophrenia, BD, or MDD.

Serum kisspeptin and proopiomelanocortin in cystic fibrosis: a single study

The determination of hormonal biomarkers is of increasing interest in many diseases, including cystic fibrosis (CF). Hormones that have not been estimated and described so far in CF include kisspeptin (KISS) and proopiomelanocortin (POMC), which are involved in the regulation of many processes, including appetite and fertility. Therefore, the aim of our study was to estimate the level of KISS and POMC in sera from CF patients and to determine the correlation between these hormones and clinical parameters. For this purpose, we estimated the levels of KISS and POMC in 38 CF patients and 16 healthy participants with enzyme-linked immunosorbent assay. We found significantly reduced levels of KISS and POMC in people with CF compared to healthy subjects (1.76 ± 0.46 vs. 2.27 ± 0.56 ng/mL, p < 0.05 and 6.25 ± 4.36 vs. 14.74 ± 6.24 ng/mL, p < 0.001, respectively). Furthermore, the level of both hormones was negatively correlated with age. The hormones studied did not correlate with the results of spirometry and each other. Thus, decreased KISS and POMC levels may be associated with lower body weight and delayed puberty in patients with CF.

Childhood trauma, the stress response and metabolic syndrome: A focus on DNA methylation

Childhood trauma (CT) is well established as a potent risk factor for the development of mental disorders. However, the potential of adverse early experiences to exert chronic and profound effects on physical health, including aberrant metabolic phenotypes, has only been more recently explored. Among these consequences is metabolic syndrome (MetS), which is characterised by at least three of five related cardiometabolic traits: hypertension, insulin resistance/hyperglycaemia, raised triglycerides, low high-density lipoprotein and central obesity. The deleterious effects of CT on health outcomes may be partially attributable to dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis, which coordinates the response to stress, and the consequent fostering of a pro-inflammatory environment. Epigenetic tags, such as DNA methylation, which are sensitive to environmental influences provide a means whereby the effects of CT can be biologically embedded and persist into adulthood to affect health and well-being. The methylome regulates the transcription of genes involved in the stress response, metabolism and inflammation. This narrative review examines the evidence for DNA methylation in CT and MetS in order to identify shared neuroendocrine and immune correlates that may mediate the increased risk of MetS following CT exposure. Our review specifically highlights differential methylation of FKBP5, the gene that encodes FK506-binding protein 51 and has pleiotropic effects on stress responding, inflammation and energy metabolism, as a central candidate to understand the molecular aetiology underlying CT-associated MetS risk.

Characterization of glucocorticoid-induced loss of DNA methylation of the stress-response gene Fkbp5 in neuronal cells

Exposure to stress or glucocorticoids (GCs) is associated with epigenetic and transcriptional changes in genes that either mediate or are targets of GC signalling. FKBP5 (FK506 binding protein 5) is one such gene that also plays a central role in negative feedback regulation of GC signalling and several stress-related psychiatric disorders. In this study, we sought to examine how the mouse Fkbp5 gene is regulated in a neuronal context and identify requisite factors that can mediate the epigenetic sequelae of excess GC exposure. Mice treated with GCs were used to establish the widespread changes in DNA methylation (DNAm) and expression of Fkbp5 across four brain regions. Then two cell lines were used to test the persistence, decay, and functional significance of GC-induced methylation changes near two GC response elements (GREs) in the fifth intron of Fkbp5. We also tested the involvement of DNMT1, cell proliferation, and MeCP2 in mediating the effect of GCs on DNAm and gene activation. DNAm changes at some CpGs persist while others decay, and reduced methylation states are associated with a more robust transcriptional response. Importantly, the ability to undergo GC-induced DNAm loss is tied to DNMT1 function during cell division. Further, GC-induced DNAm loss is associated with reduced binding of MeCP2 at intron 5 and a physical interaction between the fifth intron and promoter of Fkbp5. Our results highlight several key factors at the Fkbp5 locus that may have important implications for GC- or stress-exposure during early stages of neurodevelopment.

Hallmarks of Health

Health is usually defined as the absence of pathology. Here, we endeavor to define health as a compendium of organizational and dynamic features that maintain physiology. The biological causes or hallmarks of health include features of spatial compartmentalization (integrity of barriers and containment of local perturbations), maintenance of homeostasis over time (recycling and turnover, integration of circuitries, and rhythmic oscillations), and an array of adequate responses to stress (homeostatic resilience, hormetic regulation, and repair and regeneration). Disruption of any of these interlocked features is broadly pathogenic, causing an acute or progressive derailment of the system coupled to the loss of numerous stigmata of health.