Inhibition of expression of glucocorticoids receptors may contribute to postpartum depression

Potential therapeutic effects of Chinese herbal medicine in postpartum depression: Mechanisms and future directions

ETHNOPHARMACOLOGICAL RELEVANCE

Postpartum depression (PPD) is a common psychiatric disorder in women after childbirth. Per data from epidemiologic studies, PPD affects about 5%-26.32% of postpartum mothers worldwide. Biological factors underlying this condition are multiple and complex and have received extensive inquiries for the roles they play in PPD. Chinese herbal medicine (CHM), which is widely used as a complementary and alternative therapy for neurological disorders, possesses multi-component, multi-target, multi-access, and low side effect therapeutic characteristics. CHM has already shown efficacy in the treatment of PPD, and a lot more research exploring the mechanisms of its potential therapeutic effects is being conducted.

AIM OF THE REVIEW

This review provides an in-depth and comprehensive overview of the underlying mechanisms of PPD, as well as samples the progress made in researching the potential role of CHM in treating the disorder.

MATERIALS AND METHODS

Literature was searched comprehensively in scholarly electronic databases, including PubMed, Web of Science, Scopus, CNKI and WanFang DATA, using the search terms "postpartum depression", "genetic", "hormone", "immune", "neuroinflammation", "inflammation", "neurotransmitter", "neurogenesis", "brain-gut axis", "traditional Chinese medicine", "Chinese herbal medicine", "herb", and an assorted combination of these terms.

RESULTS

PPD is closely associated with genetics, as well as with the hormones, immune inflammatory, and neurotransmitter systems, neurogenesis, and gut microbes, and these biological factors often interact and work together to cause PPD. For example, inflammatory factors could suppress the production of the neurotransmitter serotonin by inducing the regulation of tryptophan-kynurenine in the direction of neurotoxicity. Many CHM constituents improve anxiety- and depression-like behaviors by interfering with the above-mentioned mechanisms and have shown decent efficacy clinically against PPD. For example, Shen-Qi-Jie-Yu-Fang invigorates the neuroendocrine system by boosting the hormone levels of hypothalamic pituitary adrenal (HPA) and hypothalamic pituitary gonadal (HPG) axes, regulating the imbalance of Treg/T-helper cells (Th) 17 and Th1/Th2, and modulating neurotransmitter system to play antidepressant roles. The Shenguiren Mixture interferes with the extracellular signal-regulated kinase (ERK) pathway to enhance the number, morphology and apoptosis of neurons in the hippocampus of PPD rats. Other herbal extracts and active ingredients of CHM, such as Paeoniflorin, hypericin, timosaponin B-III and more, also manage depression by remedying the neuroendocrine system and reducing neuroinflammation.

CONCLUSIONS

The pathogenesis of PPD is complex and diverse, with the main pathogenesis not clear. Still, CHM constituents, like Shen-Qi-Jie-Yu-Fang, the Shenguiren Mixture, Paeoniflorin, hypericin and other Chinese Medicinal Formulae, active monomers and Crude extracts, treats PPD through multifaceted interventions. Therefore, developing more CHM components for the treatment of PPD is an essential step forward.

The role of stress in perinatal depression and anxiety - A systematic review

Perinatal depression (PND) and anxiety affect around 20% of women, but available pharmacotherapy is not sufficiently effective in 20-60% of them, indicating a need for better understanding of these diseases. Since stress is a significant risk factor for PND, the aim was to examine the role of biological, environmental and psychological stress in PND and anxiety through a systematic literature search. Overall 210 studies were included, among which numerous rodent studies showed that perinatal stress induced depressive-like and anxious behavior, which was associated with HPA-axis alterations and morphological brain changes. Human studies indicated that the relationship between cortisol and perinatal depression/anxiety was not as clear and with many contradictions, although social and psychological stress were clearly positively associated with PND. Finally, oxytocin, synthetic neuroactive steroid and n-3 PUFA diet have been identified as potentially beneficial in the therapy of PND and anxiety, worth to be investigated in the future.

Resveratrol alleviates postpartum depression-like behavior by activating autophagy via SIRT1 and inhibiting AKT/mTOR pathway

BACKGROUND

Postpartum depression (PPD) causes maternal mortality, and has a high disability rate. In recent years, studies have suggested the Sirt1 gene to be involved in the pathogenesis of depression. Resveratrol (RSV), an activator of Sirt1, has been investigated in depressive behavior. However, its effect on PPD remains to be thoroughly elucidated.

METHODS

We employed a mice model with bilateral oophorectomy combined with hormone-simulated pregnancy to assess postpartum depression-like behavior. The behavioral tests were performed 2 days after the withdrawal of estradiol benzoate. RSV was administered subcutaneously to the PPD model mice. Several behavioral tests were executed, including the open field test, forced swimming test, and tail suspension test. Western blot analyses and immunofluorescence staining were used to evaluate protein expression levels of SIRT1, autophagy markers, and the AKT/mTOR.

RESULTS

Postpartum depressive-like behavior was triggered following the withdrawal of estradiol benzoate after hormone-stimulated-pregnancy. RSV improved postpartum depressive-like behavior of mice via its upregulation of the SIRT1 and autophagy markers, such as Beclin1, ATG5 and LC3B. Also, the downregulation of the p62 protein expression was observed. More importantly, we also detected the inhibition of phosphorylated AKT and mTOR in the hippocampus of postpartum depressive-like mice.

CONCLUSION

RSV could alleviate postpartum depression-like behavior in mice by stimulating the SIRT1, induce autophagy and inhibit the AKT/ mTOR signaling pathway.

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

Objective

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

Materials and methods

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

Results

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

Conclusion

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

Post-partum depression: From clinical understanding to preclinical assessments

Post-partum depression (PPD) with varying clinical manifestations affecting new parents remains underdiagnosed and poorly treated. This minireview revisits the pharmacotherapy, and relevant etiological basis, capable of advancing preclinical research frameworks. Maternal tasks accompanied by numerous behavioral readouts demand modeling different paradigms that reflect the complex and heterogenous nature of PPD. Hence, effective PPD-like characterization in animals towards the discovery of pharmacological intervention demands research that deepens our understanding of the roles of hormonal and non-hormonal components and mediators of this psychiatric disorder.

Hot spots and frontiers of postpartum depression research in the past 5 years: A bibliometric analysis

Objective

This study applied the bibliometric method to analyze the hotspots and frontiers in the field of postpartum depression research from 2017 to 2021.

Methods

A computer-based search for studies related to postpartum depression (PPD) was conducted in the Web of Science Core Collection from 2017 to 2021. Using CiteSpace 5.8. R3 visualization software, this paper analyzed the hot spots and frontiers of postpartum depression research from countries, institutions, authors, cited references and keywords, and drew corresponding knowledge maps.

Results

A total of 3,789 articles were retrieved, and the annual publication volume showed a steady increase. The countries and institutions with the most publications were the United States and the University of Toronto, respectively. Cindylee Dennis was the most productive author. The most frequently cited and centrally cited articles were meta-analyses on risk factors associated with antenatal depression or anxiety and meta-analyses on the prevalence of antenatal or postnatal anxiety, respectively. The research hotspots in the field of postpartum depression in the past 5 years mainly focused on the risk factors for PPD, and the impact of the COVID-19 epidemic on PPD. Providing various aspects of social and family support to women with PPD may be a research trend in this field.

Conclusion

This study provides a trend and frontier in the field of postpartum depression, and valuable information for researchers to find potential partners and partner countries, and a reference for future research topics and development directions.

Human neural stem cells secretome inhibits lipopolysaccharide-induced neuroinflammation through modulating microglia polarization by activating PPAR-γ

Neuroinflammation is one of the typical events in multiple neurodegenerative diseases, whereas microglia are the critical participants in the pathogenesis of neuroinflammation. Several studies suggest that neural stem cells (NSCs) present immunomodulatory benefits due to their paracrine products, which contain mounting trophic factors. In the current study, the anti-inflammatory effects of neural stem cells secretome (NSC-S) on lipopolysaccharide (LPS)-induced neuroinflammatory models were evaluated in vivo and the underlying mechanism was further investigated in vitro. It was revealed that NSC-S significantly attenuated the severity of LPS-induced behaviour disorders and inflammatory response in mice. In vitro studies found that NSC-S significantly promoted the polarization of microglia from proinflammatory M1 to anti-inflammatory M2 phenotype, and reduced the production of proinflammatory cytokines while elevated anti-inflammatory cytokines in BV2 cells. NSC-S promoted peroxisome proliferator-activated receptor gamma (PPAR-γ) pathway activation. However, these effects of NSC-S were abrogated by PPAR-γ inhibitor GW9662. Notably, the fatty acid binding protein 5 (FABP5) in NSC-S may mediate PPAR-γ activation and inflammation remission. In summary, NSC-S promotes the regression of LPS-induced microglia-mediated inflammation through the PPAR-γ pathway. This function might be achieved via FABP5.

Animal models of postpartum depression revisited

Postpartum depression (PPD) is a heterogeneous mood disorder and the most frequent psychiatric complication of the postnatal period. Given its potential long-lasting repercussions on the well-being of the mother and the infants, it should be a priority in public health. In spite of efforts devoted to clinical investigation and preclinical studies, the underlying neurobiological mechanisms of this disorder remain unknown in detail. Much of the progress in the area has been made from animal models, especially rodent models. The aim of this mini-review is to update the current rodent models in PPD research and their main contributions to the field. Animal models are critical tools to advance understanding of the pathophysiological basis of this disorder and to help the development of new therapeutic strategies. Here, we group PPD models into 2 main categories (Models based on hormone manipulations, Models based on stress exposure), each of which includes different paradigms that reflect risk factors or physiological conditions associated with this disease. Finally, we provide an overview of emerging models that provide new perspectives on the study of possible pathophysiological factors related to PPD, to contribute to tackling potential therapeutic targets.

Ameliorative effect of SIRT1 in postpartum depression mediated by upregulation of the glucocorticoid receptor

Recent evidence has confirmed the association of glucocorticoid receptor (GR) gene variants with the "stress" endocrine axis in postpartum depression (PPD). Sirtuin 1(SIRT1) is an NAD⁺-dependent histone deacetylase and transcriptional enhancer of GR. However, to date, the function of the SIRT1 gene in the regulation of GR expression in PPD remains to be fully determined. A hormone-stimulated pregnancy (HSP) and subsequent "postpartum" withdrawal of estrogen was employed to mimic the fluctuations in estradiol associated with pregnancy and postpartum. We confirmed that estradiol benzoate withdrawal (EW)-rats displayed depression- and anxiety-like behaviors. These behavioral dysfunctions are associated with attenuated expression of SIRT1 and GR in the hippocampus. To assess the role of SIRT1, as well as its regulatory target directly, a selective SIRT1 activator (SRT2104) was infused into the hippocampus of EW-rats. We found that pharmacological activation of hippocampal SIRT1 blocks the development of depression-related, but not anxiety-related, phenotypes of PPD. In addition, the activation of SIRT1 leads to an increase in hippocampal GR expression in EW-rats. We further confirmed that SIRT1 physically interacts with GR in a glucocorticoid-dependent manner. Taken together, our results suggest that neuropathology in PPD is caused, at least in part, by the inhibition of the SIRT1-GR signaling pathway. Elevating SIRT1 levels, either pharmacologically or through other means, could represent a therapeutic strategy for PPD.