The Bidirectional Relationship of Depression and Inflammation: Double Trouble

Peripheral mitochondrial DNA as a neuroinflammatory biomarker for major depressive disorder

In the pathogenesis of major depressive disorder, chronic stress-related neuroinflammation hinders favorable prognosis and antidepressant response. Mitochondrial DNA may be an inflammatory trigger, after its release from stress-induced dysfunctional central nervous system mitochondria into peripheral circulation. This evidence supports the potential use of peripheral mitochondrial DNA as a neuroinflammatory biomarker for the diagnosis and treatment of major depressive disorder. Herein, we critically review the neuroinflammation theory in major depressive disorder, providing compelling evidence that mitochondrial DNA release acts as a critical biological substrate, and that it constitutes the neuroinflammatory disease pathway. After its release, mitochondrial DNA can be carried in the exosomes and transported to extracellular spaces in the central nervous system and peripheral circulation. Detectable exosomes render encaged mitochondrial DNA relatively stable. This mitochondrial DNA in peripheral circulation can thus be directly detected in clinical practice. These characteristics illustrate the potential for mitochondrial DNA to serve as an innovative clinical biomarker and molecular treatment target for major depressive disorder. This review also highlights the future potential value of clinical applications combining mitochondrial DNA with a panel of other biomarkers, to improve diagnostic precision in major depressive disorder.

Coenzyme Q10 and vitamin E alleviate heat stress-induced mood disturbances in male mice: Modulation of inflammatory pathways and the HPA axis

Heat stress, as an environmental stressor, can lead to temperature dysregulation and neuroinflammation, causing depression and anxiety by disrupting brain physiology and functional connectivity. This study looked at how co-enzyme Q10 (Q10) and vitamin E (Vit E), alone and together, affected heat stress-caused anxiety and depression symptoms and inflammation in male mice. Five groups were utilized in the study: control, heat stress (NS), Q10, Vit E, and the combination group (Q10+Vit E). The mice were subjected for 15 min/day to a temperature of 43°C for 14 consecutive days, followed by daily treatments for two weeks with either normal saline, Q10 (500 mg/kg), Vit E (250 mg/kg), or their combination. The forced swimming test (FST) and tail suspension test (TST) were employed to evaluate despair behavior, whereas the elevated plus maze (EPM) and open field test (OFT) were used to assess anxious behaviors. Subsequently, the animals were sacrificed, and serum corticosterone levels, protein expression of inflammasome-related proteins, and hsp70 gene expression were evaluated in the prefrontal cortex (PFC). The study revealed that treatment with Vit E and Q10, alone or together, provided anxiolytic and antidepressant effects in the heat-stress-subjected animals. Also, giving Vit E and Q10 alone or together greatly lowered serum corticosterone levels. In the PFC, they also lowered the levels of hsp70 mRNA and NF-κB, caspase 1, NLRP3, and IL-1β proteins. It is speculated that treatment with Q10 and Vit E can attenuate heat stress-associated anxious and depressive responses by inhibiting the inflammatory pathways and modulating the hypothalamus-pituitary-adrenal axis.

Running exercise decreases microglial activation in the medial prefrontal cortex in an animal model of depression

BACKGROUND

Running exercise effectively ameliorates depressive symptoms in humans and depression-like behaviors in animals, but the underlying mechanisms remain unclear. Microglia-mediated neuroinflammation plays a major role in the development of depression. The medial prefrontal cortex (mPFC) is a key brain region involved in depression and is sensitive to physical activity. Whether the antidepressant effect of running exercise involves changes in mPFC microglia is not understood.

METHODS

The animals were subjected to chronic unpredictable stress (CUS) intervention followed by treadmill running. The sucrose preference test and elevated plus maze test or tail suspension test were used for behavioral assessment of the animals. The number of microglia in the mPFC was quantified by immunohistochemistry and stereology. The density and morphology of microglia were analyzed via immunofluorescence staining combined with three-dimensional laser scanning techniques. The mRNA expressions of inflammatory cytokines in the mPFC were examined via quantitative real-time PCR.

RESULTS

Running exercise effectively alleviated depressive-like behaviors in depression model animals. Running exercise reversed the increase in the number of microglia and the density of activated microglia in the mPFC of CUS animals. Running exercise effectively reversed the changes in microglia (reduced cell body area, total branch length and branch complexity) in the mPFC of CUS animals. Furthermore, running exercise regulated the gene expressions of pro-/antiinflammatory cytokines in the mPFC of CUS animals.

CONCLUSIONS

Our results suggested that the antidepressant effects of running exercise may involve decreasing the number of activated microglia, reversing morphological changes in microglia in the mPFC, and reducing inflammatory responses.

Association between the platelet/high-density lipoprotein cholesterol ratio and depression: A cross-sectional analysis in United States adults

BACKGROUND

The primary objective of this study was to elucidate the relationship between the platelet/high-density lipoprotein cholesterol ratio (PHR) and the risk of depression in adults in the US.

METHODS

We conducted a cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2016. Depression was assessed using the PHQ-9 questionnaire. Weighted multivariable logistic regression models and restricted cubic spline (RCS) models were used to study the relationship between PHR and the risk of depression. Subgroup and interaction analyses were performed to further understand these associations.

RESULTS

A total of 21,454 participants were included in this study. After full adjustment, PHR was significantly positively correlated with depression (OR = 1.33, 95%CI: 1.03-1.73). When PHR was converted into a categorical variable based on quartiles (Q1-Q4), the highest quartile of PHR was associated with an increased risk of depression compared to the lowest reference group (OR = 1.22, 95%CI: 1.01-1.48). There was a linear dose-response relationship between PHR and the risk of depression (P-non-linear = 0.8038). The association remained significant in several subgroup analyses. However, the interaction test showed that none of the stratified variables were significant (all P for interaction >0.05).

LIMITATION

Using self-assessment scales and inability to assess causality.

CONCLUSION

This population-based cross-sectional study elucidated that PHR is significantly associated with an increased prevalence of depression in adults in the US.

From blood to brain: Exploring the role of fibrinogen in the pathophysiology of depression and other neurological disorders

Recent findings indicate that fibrinogen, a protein involved in blood clotting, plays a significant role in neuroinflammation and mood disorders. Elevated fibrinogen levels are consistently observed in individuals with depression, potentially contributing to microglial activation. This could impair fibrinolysis and contribute to a pro-inflammatory environment in the brain. This neuroinflammatory response can impair neuroplasticity, a key process for learning, memory, and mood regulation. Fibrinogen may also indirectly influence neurotransmitters like serotonin, which play a vital role in mood regulation. Furthermore, fibrinogen's interaction with astrocytes may trigger a cascade of events leading to demyelination, a process where the protective sheath around nerve fibers deteriorates. This can disrupt communication within the nervous system and contribute to depression symptoms. Intriguingly, targeting fibrinogen or related pathways holds promise for therapeutic interventions. For instance, modulating PAI-1 (Plasminogen activator inhibitor-1) activity or inhibiting fibrinogen's interaction with brain cells could be potential strategies. This review explores the multifaceted relationship between fibrinogen and neurological disorders with a focus on depression highlighting its potential as a therapeutic target. Further research is necessary to fully elucidate the mechanisms underlying this association and develop effective therapeutic strategies targeting the fibrinolytic system for mood disorders.

Neuroprotective effects of gypenosides on LPS-induced anxiety and depression-like behaviors

AIM

Depression, a prevalent mental disorder, significantly impairs the quality of life and social functioning. Targeting neuroinflammation is a promising therapeutic approach, highlighting the need for natural neuroprotective agents. Gypenosides (Gyp) from Gynostemma pentaphyllum exhibit anxiolytic and antidepressant effects, yet the underlying mechanisms remain unclear. We investigated whether Gyp, isolated and purified by our laboratory, can exert neuroprotective effects by modulating neuroinflammation in the hippocampus and prefrontal cortex (PFC) of mice with LPS-induced anxiety and depression, thereby ameliorating behavioral phenotypes.

METHODS

LPS (1 mg/kg, i.p.) was used to induce anxiety and depression-like behaviors. Gyp was administered at 50, 100, or 200 mg/kg in pretreatment, with fluoxetine hydrochloride (Flu) as a positive control, for 10 consecutive days.

RESULTS

Gyp, especially at 100 mg/kg, significantly ameliorated LPS-induced anxiety and depression in mice, normalizing cytokine expression in the hippocampus and PFC, with IL-1β showing the most pronounced regulation (Hippocampus: RatioGyp-100/LPS = 30.73 %, PFC: RatioGyp-100/LPS = 55.89 %). Gyp also reversed LPS-induced neuronal loss and necrosis, reduced glial cell activation, and prevented the transition of microglia to the M1 phenotype. Mechanistically, Gyp suppressed the activation of the NLRP3 inflammasome in the PFC, and modulated hippocampal synaptic protein loss, thereby mediating neuroinflammation.

CONCLUSIONS

Gyp improved anxiety and depression in LPS-induced mice, which may be achieved by balancing systemic inflammatory levels, regulating glial cell activation and phenotypic polarization, regulating hippocampal synaptic plasticity, and suppressing the NLRP3/Caspase-1/ASC signaling pathway in the PFC.

The triangular relationship of physical activity, depression, and inflammatory markers: A large cross-sectional analysis with NHANES data

Depression is a major public health problem worldwide and is closely related with systemic inflammatory responses. Additionly, physical activity (PA) is thought to be associated with lower levels of depression and inflammatory markers. This study aimed to elucidate the complex interactions between PA, depression, and inflammatory markers. Based on the National Health and Nutrition Examination Survey (NHANES), various logistic regression were applied to analyze the pairwise correlations among the three. Restrictive cubic splines were constructed to explore the nonlinear relationship between PA and depression. Mediation models were used to identify the mediating role of inflammatory markers. The findings revealed a positive link between depression and inflammatory marker, whereas PA was inversely correlated with both inflammatory marker and depression. Particularly, we noticed the greatest reduction in the risk of depression when the level of PA was between 1200 and 1722 MET-min/week. Besides, we demonstrated that inflammatory markers mediate the potential effects of physical inactivity on depression, ranging from 1.72 % to 6.25 %. In conclusion, PA appear to protect against depression, in which inflammatory markers may play a mediating role. Moreover, we determined the optimal dosage of PA to minimize the likelihood of depression, thereby offering valuable guidance for managing depression.

A refined formula derived from Jiawei-Xiaoyao pill exerts rapid antidepressant-like effects in LPS-induced depression by reducing neuroinflammation and restoring neuroplasticity signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Jiawei-Xiaoyao Pill (JWX), a classic formula in traditional Chinese medicine, is derived from Xiaoyao Pill by adding significant amounts of Gardeniae Fructus (GF) and Moutan Cortex (MC). It is frequently used for the treatment of depression. JWX has been demonstrated to uniquely elicit rapid antidepressant-like effects within the prescribed dosage range. To date, GF has been shown to have rapid antidepressant-like effects, but a much higher dose is required than its proportion in JWX. It is assumed that the synergism of GF with a minimum number of other herbs in JWX serves as a refined formula that exerts these rapid antidepressant-like effects. Identification of a refined formula is important for prioritizing the herbs and ingredients to optimize the quality control of JWX. However, such a refined formula for JWX has not been identified yet.

AIM OF THE STUDY

Here we aimed to identify a refined formula derived from JWX for optimized rapid antidepressant-like effects. Since the neuroinflammation mechanism involving in depression treatment has not been previously investigated for JWX, we tested the mechanism for both JWX and the refined formula.

MATERIALS AND METHODS

Individual herbs (MC; ASR, Angelica Sinensis Radix; Bupleuri Radix; Paeonia Radix Alba) that show antidepressant-like responses were mixed with GF at the proportional dosage in JWX to identify the refined formula. Rapid antidepressant-like effects were assessed by using NSF (Novelty Suppressed Feeding Test) and other behavioral tests following a single administration. The identified formula was further tested in a lipopolysaccharide (LPS)-induced depressive model, and the molecular signaling mechanisms were investigated using Western blot analysis, immunofluorescence, and pharmacological inhibition of mTOR signaling. Scopolamine (Scop) was used as a positive control for induction of rapid antidepressant effects.

RESULTS

A combination of GF, MC and ASR (GMA) at their dosages proportional to JWX induced behavioral signs of rapid antidepressant-like responses in both normal and LPS-treated mice, with the antidepressant-like effects sustained for 5 d. Similar to JWX or Scop, GMA rapidly reduced the neuroinflammation signaling of Iba-1-NF-кB, enhanced neuroplasticity signaling of CaMKII-mTOR-BDNF, and attenuated the upregulated expressions of the NMDAR sub-units GluN1 and GluN2B in the hippocampus of LPS-treated mice. GMA, JWX and Scop rapidly restored the number of BDNF-positive cells reduced by LPS treatment in the CA3 region of the hippocampus. Furthermore, rapamycin, a selective inhibitor of mTOR, blunted the rapid antidepressant-like effects and hippocampal BDNF signaling upregulation by GMA.

CONCLUSION

GMA may serve as a refined formula from JWX, capable of inducing rapid antidepressant-like effects. In the LPS-induced depression model, the effects of GMA were mediated via rapidly alleviating neuroinflammation and enhancing neuroplasticity.

Xiaoyaosan against depression through suppressing LPS mediated TLR4/NLRP3 signaling pathway in "microbiota-gut-brain" axis

ETHNOPHARMACOLOGICAL RELEVANCE

Depression impairs not only central nervous system, but also peripheral systems of the host. Gut microbiota have been proved to be involved in the pathogenesis of depression. Xiaoyaosan (XYS) has a history of over a thousand years in China for treating depression, dramatically alleviating anxiety, cognitive disorders, and especially gastrointestinal dysfunctions. Yet, it still just scratches the surface of the anti-depression mechanisms of XYS.

AIM OF THE STUDY

This study aims to elucidate the mechanism of actions of XYS from the perspective of "microbiota-gut-brain" axis.

MATERIALS AND METHODS

We firstly evaluated the effects of XYS on the macroscopic behaviors of depressed rats that induced by chronic unpredictable mild stress (CUMS). Secondly, the effects of XYS on intestinal homeostasis of depressed rats were revealed by using dysbacteriosis model. Subsequently, the underlying mechanisms were demonstrated by 16S rRNA gene sequencing technology and molecular biology methods. Finally, correlation analysis and visualization of the anti-depression effects of XYS were performed from the "microbiota - gut - brain" perspective.

RESULTS

Our data indicated that XYS ameliorated the depression-like symptoms of CUMS rats, partly depending on the presence of gut microbiota. Furthermore, we illustrated that XYS reversed CUMS-induced gut dysbiosis of depressed rats in terms of decreasing the Bacteroidetes/Firmicutes ratio and the abundances of Bacteroides, and Corynebacterium, while increasing the abundances of Lactobacillus and Adlercreutzia. The significant enrichment of Bacteroides and the level of lipopolysaccharides (LPS) suggested that depression damaged the immune responses and gut barrier. Mechanistically, XYS significantly down-regulated the expression levels of factors that involved in TLR4/NLRP3 signaling pathway in the colon and brain tissues of depressed rats. In addition, XYS significantly increased the levels of claudin 1 and ZO-1, showing that XYS positively maintained the integrity of gut and blood-brain barriers (BBB).

CONCLUSION

Our study offers insights into the anti-depression effects of XYS through a lens of "microbiota-TLR4/NLRP3 signaling pathway-barriers", providing a foundation for enhancing clinical efficiency and enriching drug selection, and contributing to our understanding of the mechanisms of traditional Chinese medicines (TCMs) in treating depression.

Pinocembrin alleviates LPS-induced depressive-like behavior in mice via the NLRP3/DCC signaling pathway

OBJECTIVE

Depression, a prevalent and severe mental disorder, continues to be a significant area of research concerning its pathogenesis and therapeutic approaches. Conventional antidepressants are often limited by delayed therapeutic effects and notable adverse reactions, necessitating the development of innovative and efficacious treatment modalities. Multiple lines of evidence suggest that peripheral and central inflammation play a role in depression, and that anti-inflammatory drugs can ameliorate depressive symptoms in patients with inflammation-related depression. Pinocembrin (PB), a natural bioactive compound, is renowned for its anti-inflammatory and antioxidant properties, while the effect and mechanism of PB are still unclear. Consequently, this study employs PB as an intervention to investigate its effects on depression in mice model, with the objective of establishing a novel therapeutic strategy and foundational data for the treatment of depression.

METHODS

(1) The acute inflammation model used lipopolysaccharide (LPS) to induce depression-like behavior in mice by injecting LPS intraperitoneally at a dose of 0.83 mg/kg. The effects of PB (20 mg/kg, i.p.) and the NLRP3 inflammasome inhibitor MCC950 (10 mg/kg, i.p.) on improving depression behavior in mice were evaluated. (2) To explore the specific mechanism of PB in improving depression-like behavior in LPS mice by regulating NLRP3 and Netrin-1/DCC pathway.

RESULTS

The results showed that after intraperitoneal injection of LPS, the mice exhibited a significant decrease in body weight, sucrose preference score, and a significant increase in tail suspension immobility time. Treatment with PB and MCC950 increased the sucrose preference score and decreased the tail suspension immobility time. Besides, PB and MCC950 could inhibit the expression of NLRP3 related neuroinflammation, down-regulated the Netrin-1/DCC signaling pathway, and improved hippocampal neuroplasticity in mice.

CONCLUSION

In conclusion, PB significantly improved LPS-induced depression-like behavior in mice by reducing the expression of hippocampal NLRP3 inflammasome and down-regulating the Netrin-1/DCC signaling pathway. Additionally, PB was found to regulate α-amino-3-hydroxy-5-methyl-4 isoxazole receptor (AMPAR) and postsynaptic density 95 (PSD95), protecting excitatory synaptic transmission and enhancing synaptic plasticity. This study demonstrates the effectiveness of PB in improving depressive symptoms induced by LPS and provides a new strategy for the clinical treatment of depression.

A cross-sectional study of non-suicidal self-injury in adults with depressive disorder: Associations with inflammation and cardiac structure and function

OBJECTIVE

Non-suicidal self-injury (NSSI) is associated with cardiovascular disease (CVD), whereas inflammation is associated with both CVD and NSSI. However, few studies have investigated the correlation among NSSI, inflammation, and cardiac structure and function in CVD-free adult patients with depressive disorders.

METHODS

We recruited 88 CVD-free adult patients with depressive disorders and 37 healthy individuals. Patients were divided into NSSI (n = 21) and non-NSSI (n = 67) groups based on the presence or absence of NSSI. Healthy individuals comprised the controls (n = 37). Echocardiography was applied to assess cardiac structure and function, and C-reactive protein (CRP) levels were measured to indicate inflammation.

RESULTS

Compared with controls, the NSSI group exhibited a larger left ventricular end-systolic diameter (LVESD) and smaller left ventricular ejection fraction (LVEF). Left ventricular end-systolic volume (LVESV) was larger in the NSSI group than in the non-NSSI group. The CRP levels were higher in the NSSI group than in the non-NSSI group; however, this difference was not statistically significant. NSSI was positively associated with LVESD (β = 1.928, p = 0.006) and LVESV (β = 5.368, p = 0.003), negatively correlated with LVEF (β = -2.600, p = 0.029), and positively correlated with CRP levels (β = 0.116, p = 0.004). CRP levels did not mediate the association between NSSI and cardiac structure and function.

CONCLUSIONS

This study indicated that NSSI was associated with left ventricular structure, systolic function, and inflammation, but CRP did not mediate the relationship between NSSI and echocardiogram parameters.

Effects of double neonatal stress on female rat sexual behaviour

Neonatal stress affects psychological and physiological development and may be associated with affective disorders. The aim was to examine the effects of double neonatal stress (DNS) - a combination of limited bedding and nesting (LBN) and repeated maternal separation (MS) - on the oestrous cycle and sexual behaviour of adult female rats. LBN was achieved by removing part of the wood shavings from the boxes. In the control group, each box was lined with 100 g of wood shavings, while in the experimental group there were only 10 g of wood shavings. MS was performed from P1 (P0 = day of birth) to P15. At P90, the sexual response of females in oestrus was evaluated. Statistical analysis was performed using two-way analysis of variance followed by Tukey's test. The size and profile of the oestrous cycle and the sexual behaviour of female rats submitted to the DNS were considered, as well as the influence of female behaviour on the sexual response of male rats. Female rats submitted to DNS showed a reduction in the lordosis quotient, suggesting a reduction in female receptivity. These rats also showed a reduction in the number of hops and darts, the number of ear wiggles, and the genital exploration time rate, suggesting a reduction in proceptivity. The males that interacted with the females of the DNS group showed a reduction in intromission ratio. Experimental model that mimics neonatal factors that affect adult female sexual response will allow more effective interventions to prevent and treat such changes. In addition, analysis of the female sexual response makes it possible to assess the general state of health and quality of life. In female rats, DNS exerted inhibitory effects on sexual behaviour. LBN was probably the most important factor. In conclusion, combating childhood poverty can be a key measure to prevent problems in the sex life of adults and improve overall health.

The Relationship of Certain Diseases and Dietary Inflammatory Index in Older Adults: A Narrative Review

PURPOSE OF REVIEW

One of the important markers affecting aging processes is the increase in inflammatory markers. Many chronic diseases are associated with inflammation and chronic inflammation increases with aging. Inflammation can change with dietary components. Foods, compounds and nutrients that have anti-inflammatory or proinflammatory properties attract attention. According to the Dietary Inflammatory Index, positive scores are obtained if the nutrient has a proinflammatory effect on cytokines, and negative scores are obtained if it has an anti-inflammatory effect.

RECENT FINDINGS

A higher proinflammatory diet is associated with cardiometabolic diseases, neurodegenerative disease, cancers and musculoskeletal health and related mortality. In this study, its relationship with type 2 diabetes mellitus, obesity, metabolic syndrome, musculoskeletal diseases, dementia, depression and cancer, which are more common in older adults and known to be associated with inflammation, was examined. Although studies involving under 65 years old are more prevalent, research involving older adults and Dietary Inflammatory Index (DII) is more limited. It is known that chronic inflammation increases with aging. Diet is one of the factors affecting inflammation. In the light of these investigations, the topics of anti-inflammatory nutrition and DII for the treatment of inflammation-related diseases in older adults are strong and open to development topics of discussion. Despite the significant interest in the potential positive effects of anti-inflammatory nutrition on diseases, contributing to clearer evidence of its protective effects on health necessitates further randomized controlled trials, in vivo, in vitro, cell, animal, human and case-control studies for better risk assessment.

Glymphatic system: a gateway for neuroinflammation

The glymphatic system is a relatively recently identified fluid exchange and transport system in the brain. Accumulating evidence indicates that glymphatic function is impaired not only in central nervous system disorders but also in systemic diseases. Systemic diseases can trigger the inflammatory responses in the central nervous system, occasionally leading to sustained inflammation and functional disturbance of the central nervous system. This review summarizes the current knowledge on the association between glymphatic dysfunction and central nervous system inflammation. In addition, we discuss the hypothesis that disease conditions initially associated with peripheral inflammation overwhelm the performance of the glymphatic system, thereby triggering central nervous system dysfunction, chronic neuroinflammation, and neurodegeneration. Future research investigating the role of the glymphatic system in neuroinflammation may offer innovative therapeutic approaches for central nervous system disorders.

Blood-derived factors to brain communication in brain diseases

Brain diseases, mainly including acute brain injuries, neurodegenerative diseases, and mental disorders, have posed a significant threat to human health worldwide. Due to the limited regenerative capability and the existence of the blood-brain barrier, the brain was previously thought to be separated from the rest of the body. Currently, various cross-talks between the central nervous system and peripheral organs have been widely described, including the brain-gut axis, the brain-liver axis, the brain-skeletal muscle axis, and the brain-bone axis. Moreover, several lines of evidence indicate that leveraging systemic biology intervention approaches, including but not limited to lifestyle interventions, exercise, diet, blood administration, and peripheral immune responses, have demonstrated a significant influence on the progress and prognosis of brain diseases. The advancement of innovative proteomic and transcriptomic technologies has enriched our understanding of the nuanced interplay between peripheral organs and brain diseases. An array of novel or previously underappreciated blood-derived factors have been identified to play pivotal roles in mediating these communications. In this review, we provide a comprehensive summary of blood-to-brain communication following brain diseases. Special attention is given to the instrumental role of blood-derived signals, positing them as significant contributors to the complex process of brain diseases. The insights presented here aim to bridge the current knowledge gaps and inspire novel therapeutic strategies for brain diseases.

Research progress on the mechanism of exercise against depression

The substantial global health burden of depression encourages the development of innovative and broadly effective interventions. This paper aimed to examine recent advancements by which exercise works as an antidepressant and recommends optimal types and quantity of exercise as supplemental therapies in treating depression. Sedentary behavior and low physical activity significantly influence the onset of depression. Being an effective treatment option, exercise can significantly reduce depression risk. Exercise exerts antidepressant effects as it modulates neurotransmitters, neuroplasticity, the immune system, and hormone levels. Effective exercise forms include yoga, strength training, and walking/jogging. Tailored exercise regimens that consider individual preferences and tolerability can improve outcomes. Regular exercise enhances general well-being and reduces depressive symptoms. Additional research is needed to understand the complex basis of exercise's effects on depression. Exercise is a cost-effective and accessible intervention for depression management that needs additional exploration. Thus, customized exercise programs, as per each patient’s needs, are essential for their successful implementation clinically.

Inhibition of HMOX1 by MAFG potentiates the development of depression‑like behavior in mice associated with astrocyte-mediated neuroinflammation

MAF bZIP transcription factor G (MAFG)-driven astrocytes have been reported to promote inflammation in the CNS. However, its function in depression, the primary cause of disability worldwide, has not been well characterized. This study investigated the possible perturbation of heme oxygenase 1 (HMOX1, also known as HO1) by the transcription factor MAFG as an underlying mechanism of the development of depression. The GSE98793 dataset was included for gene expression analysis of whole blood from donors with major depressive disorder and controls, and the target of MAFG was predicted by multiple database mining. Mouse and cellular models of depression were established by chronic unpredictable mild stress (CUMS) and lipopolysaccharide (LPS) treatment of astrocytes, which were treated with MAFG and HMOX1 knockdown plasmids. MAFG was highly expressed in the hippocampal tissues of CUMS-challenged mice and LPS-induced astrocytes. MAFG knockdown alleviated depression-like behaviors in mice. MAFG bound to the HMOX1 promoter and repressed its transcription. Knockdown of HMOX1 exacerbated neuroinflammation in astrocytes and accelerated depression-like behavior in mice. In conclusion, MAFG knockdown attenuated CUMS-stimulated depression-like behaviors in mice by astrocyte-mediated neuroinflammation via restoration of HMOX1.

Embracing complexity in psychiatry-from reductionistic to systems approaches

The understanding and treatment of psychiatric disorders present unique challenges due to these conditions' multifaceted nature, comprising dynamic interactions between biological, psychological, social, and environmental factors. Traditional reductionistic approaches often simplify these conditions into linear cause-and-effect relationships, overlooking the complexity and interconnectedness inherent in psychiatric disorders. Advances in complex systems approaches provide a comprehensive framework to capture and quantify the non-linear and emergent properties of psychiatric disorders. This Personal View emphasises the importance of identifying rules for generative models that govern brain and behaviour over time, which might contribute to personalised assessments and interventions for psychiatric disorders. For instance, mood fluctuations in bipolar disorder can be understood through dynamical systems modelling, which identifies modifiable parameters, such as circadian disruption, that can be addressed through targeted therapies such as light therapy. Similarly, recognition of depression as an emergent property arising from complex interactions highlights the need for integrated treatment strategies that enhance adaptive reactions in the individual. A framework for quantifying multilevel interactions and network dynamics can help researchers and clinicians to understand the interplay between neural circuits, behaviours, and social contexts. Probabilistic models and self-organisation concepts contribute to building concrete dynamical systems models of mental disorders, facilitating early identification of risk states and promoting resilience through adaptive interventions delivered with optimal timing. Embracing these complex systems approaches in psychiatry could capture the true nature of psychiatric disorders as properties of a dynamic complex system and not the manifestation of any lesion or insult. This line of thinking might improve diagnosis and treatment, offering new hope for individuals affected by psychiatric conditions and paving the way for more effective, personalised mental health care.

Depression in childhood to early adulthood and respiratory health in early adulthood

BACKGROUND

Both depression and respiratory disease are common today in young populations. However, little is known about the relationship between them.

AIMS

This study aims to explore the association between depression in childhood to early adulthood and respiratory health outcomes in early adulthood, and the potential underlying mechanisms.

METHOD

A prospective study was conducted based on the Swedish BAMSE (Barn, Allergi, Miljö, Stockholm, Epidemiologi [Children, Allergy, Milieu, Stockholm, Epidemiology]) birth cohort (n = 4089). We identified clinically diagnosed depression through the dispensation of antidepressants, using national register data confirmed by self-reported diagnosis. At the 24-year follow-up, respiratory health was assessed via questionnaires and clinical evaluation. Metabolic and inflammatory profiles were analysed to explore potential mechanisms.

RESULTS

Among the 2994 participants who provided study data, 403 (13.5%) had depression at any time point from around age 10 to 25 years. Depression was associated with higher risks of any chronic bronchitis symptoms (odds ratio = 1.58, 95% CI 1.21-2.06) and respiratory symptoms (odds ratio = 1.41, 95% CI 1.11-1.80) in early adulthood, independent of body mass index (BMI) and smoking status. Compared to individuals without depression, those with depression had a higher fat mass index (FMI (β = 0.48, 95% CI 0.22-0.74)) and increased blood levels of fibroblast growth factor 21 and Interleukin-6 in early adulthood. These markers together with FMI were found to partly mediate the association between depression and respiratory symptoms (total mediation proportion: 19.8 and 15.4%, respectively, P < 0.01).

CONCLUSIONS

Depression in childhood to early adulthood was associated with an increased risk of respiratory ill-health in early adulthood, independently of smoking. Metabolic and inflammatory dysregulations may underlie this link.

Integrated Profiling Identifies Long-Term Molecular Consequences of Prenatal Dexamethasone Treatment in the Rat Brain-Potential Triggers of Depressive Phenotype and Cognitive Impairment

Prenatal excess of glucocorticoids (GCs) is considered to be one of the highly impacting factors contributing to depression development. Although GCs are crucial for normal fetal development and their administration (mainly dexamethasone, DEX) is a life-saving procedure for those at risk of preterm delivery, exposure to excess levels of GCs during pregnancy can yield detrimental consequences. Therefore, we aimed to systematically investigate the brain molecular alterations triggered by prenatal DEX administration. We used a rat model of depression based on prenatal exposure to DEX and performed integrative multi-level methylomic, transcriptomic, and proteomic analyses of adult rats' brains (i.e., frontal cortex (FCx) and hippocampus (Hp)) to identify the outcomes of DEX action. Each of the investigated levels was significantly affected by DEX in the long-term manner. Particularly, we found 200 CpG islands to be differentially methylated in the FCx and 200 in the Hp of prenatally DEX-treated rats. Global transcriptomic analysis uncovered differential expression of transcripts mostly in FCx (271) and 1 in Hp, while proteomic study identified 146 differentially expressed proteins in FCx and 123 in Hp. Among the identified enriched molecular networks, we found altered pathways involved in synaptic plasticity (i.e., cAMP, calcium, and Wnt signaling pathways or tight junctions and adhesion molecules), which may contribute to cognitive impairment, observed in DEX-treated animals. Moreover, in the FCx, DEX administration in the prenatal period downregulates the expression of ribosome protein genes associated both with large and small ribosomal subunit assembly which can lead to a global decrease in translation and protein synthesis processes and, indirectly, alterations in the neurotransmission process.

Cognitive impairment in individuals with rheumatic diseases: the role of systemic inflammation, immunomodulatory medications, and comorbidities

Inflammation is an important risk factor, a potential therapeutic target for cognitive decline and dementia, and an inherent feature of autoimmune and immune-mediated rheumatic diseases. The risk of cognitive impairment and dementia is increased in individuals with immune-mediated rheumatic diseases, particularly in those with cardiovascular risk factors and cardiovascular disease. Immunomodulatory medications have been associated with a reduced risk of dementia, but whether this effect is mediated through their anti-inflammatory immunomodulating properties or other mechanisms, such as cardiovascular risk reduction, is unclear. A better understanding of the role of chronic inflammation as a modifiable risk factor for cognitive performance in rheumatic diseases will help inform opportunities for the management of cognitive impairment in people with rheumatic diseases and other chronic inflammatory diseases. In this Series paper, we discuss the epidemiology, risk factors, and current evidence on the role of immunomodulatory medications in cognitive impairment and dementia in people with rheumatic diseases.

The impact of acupuncture on the brain function of patients with mild to moderate major depressive disorder: a randomized controlled trial protocol

INTRODUCTION

Major depressive disorder (MDD) is a common mental disease that significantly impact the daily lives of those affected. Acupuncture has shown promising therapeutic effects in the treatment of MDD, but its underlying mechanisms remain unclear. This study aims to evaluate the influence of acupuncture on the brain function of patients with MDD and it's therapeutic effects on MDD.

METHODS

This study plans to recruit 112 participants, who will be randomly allocated to either the acupuncture group or the sham acupuncture group in a 1:1 ratio. Both groups will undergo 8 weeks of treatment, consisting of three sessions per week, with each session lasting for 30 min. A follow-up period of 3 months will be conducted after the treatment. Assessments will be conducted at weeks 0, 8, 12, 16, and 20 in this study. The primary outcome measure will be functional near-infrared spectroscopy (fNIRS) brain imaging, while secondary outcome measures will include Beck Depression Inventory II (BDI-II), Self-Rating Anxiety Scale (SAS), 36-Item Short Form Survey Instrument (SF-36), Traditional Chinese Medicine (TCM) syndrome score scale, and symptom elimination rate.

DISCUSSION

While acupuncture has been confirmed to have a certain degree of therapeutic efficacy in the treatment of MDD, research on the mechanisms underlying acupuncture's treatment of MDD remains limited, particularly with regards to its impact on the brain function of individuals with MDD. This study aims to explore both the clinical effectiveness and treatment mechanisms of acupuncture for MDD, with a specific focus on its influence on brain function. This research endeavors to provide new insights into the potential of acupuncture as a therapeutic approach for the treatment of MDD in the future.

TRIAL REGISTRATION

www.chictr.org.cn , ID: ChiCTR2300076292. Registered on 28 September 2023.

Risk factors and prognosis of depression in Takayasu arteritis patients

Background

Takayasu arteritis (TA) is associated with an increased risk of developing complicated comorbidities, which can bring both psychological and physical burdens to the patients.

Objective

TA is found to carry a high risk of developing depression. This research aimed to investigate the risk factors and prognosis of depression in TA patients.

Design

A longitudinal observation cohort was conducted on TA patients with or without depression to explore the clinical characteristics.

Methods

In this cohort study, 90 TA patients were split into two groups with or without depression. Depression was evaluated by the Hospital Anxiety and Depression Scale (HADS) in TA patients. TA patients with depression were followed up for at least 3 months. We used multivariate logistic regression analysis to find the risk factors and Kaplan-Meier curve analysis to determine the prognosis.

Results

We concluded 90 TA patients in this research, 29 of whom were in depression. Indian Takayasu's Arteritis Activity Score (ITAS2010) ⩾2 (odds ratio (OR) (95% confidence interval, CI) 26.664 (2.004-354.741), p = 0.013), interleukin-6 (IL-6) (OR (95% CI) 1.070 (1.022-1.121), p = 0.004), prednisone equivalents (OR (95% CI) 1.101 (1.030-1.177), p = 0.005), and carotidynia (OR (95% CI) 5.829 (1.142-29.751), p = 0.034) have been shown independent risk factors for depression in TA patients. We also identified the association between disease remission with the improvement of HADS-D score (Log-rank p = 0.005, hazard ratio (HR) 0.25) and depression (Log-rank p = 0.043, HR 0.28).

Conclusion

Aggressive treatment to achieve remission can promote improvement of depression in patients with TA. Screening for depression should also be performed in patients with elevated disease activity, IL-6, glucocorticoid use, and carotidynia.

Rural-urban differences in the association between afternoon napping and depressive symptoms among middle-aged and older adults in China

OBJECTIVE

This study aimed to examine the association between afternoon napping and depressive symptoms among Chinese middle-aged and older adults and to evaluate the rural-urban differences.

METHODS

A total of 11,056 participants, aged≥45, 5646 rural and 5410 urban, were included using data from CFPS. Each participant provided data on afternoon napping through field interviews. CESD8 was used to measure depressive symptoms. Multivariable logistic regressions were used to investigate the association.

RESULTS

2654 (24.01 %) participants had depressive symptoms and 7239 (65.48 %) napped. Nappers were likely to have a lower risk of depressive symptoms (OR = 0.899; 95%CI =0.816-0.991). A significantly lower risk of depressive symptoms was found in the moderate-duration afternoon napping groups (31-60 min/day) compared with non-nappers (OR = 0.816; 95%CI =0.727-0.917). In terms of rural-urban differences, rural participants had a lower risk of depressive symptoms compared with non-nappers (OR = 0.813; 95%CI =0.716-0.926). A significant association was also found between age groups. Participants aged 65-74 years old had a lower risk of depressive symptoms compared with non-nappers (OR = 0.776; 95%CI = 0.627-0.959).

LIMITATIONS

First, the cross-sectional study may limit the ability to infer causality. Second, only those who responded to the questionnaire were included; selection bias was unavoidable. Finally, answers were retrospective self-reported, which may cause recall bias and social desirability bias.

CONCLUSIONS

Afternoon napping was associated with a lower risk of depressive symptoms among Chinese middle-aged and older adults. The associations varied between rural-urban and age. We recommend taking a moderate-duration afternoon napping every day to prevent the risk of potential depression.

Luteolin ameliorates chronic stress-induced depressive-like behaviors in mice by promoting the Arginase-1+ microglial phenotype via a PPARγ-dependent mechanism

Accumulating evidence shows that neuroinflammation substantially contributes to the pathology of depression, a severe psychiatric disease with an increasing prevalence worldwide. Although modulating microglial phenotypes is recognized as a promising therapeutic strategy, effective treatments are still lacking. Previous studies have shown that luteolin (LUT) has anti-inflammatory effects and confers benefits on chronic stress-induced depression. In this study, we investigated the molecular mechanisms by which LUT regulates the functional phenotypes of microglia in mice with depressive-like behaviors. Mice were exposed to chronic restraint stress (CRS) for 7 weeks, and were administered LUT (10, 30, 40 mg· kg-1 ·day-1, i.g.) in the last 4 weeks. We showed that LUT administration significantly ameliorated depressive-like behaviors and decreased hippocampal inflammation. LUT administration induced pro-inflammatory microglia to undergo anti-inflammatory arginase (Arg)-1+ phenotypic polarization, which was associated with its antidepressant effects. Furthermore, we showed that LUT concentration-dependently increased the expression of PPARγ in LPS + ATP-treated microglia and the hippocampus of CRS-exposed mice, promoting the subsequent inhibition of the NLRP3 inflammasome. Molecular dynamics (MD) simulation and microscale thermophoresis (MST) analysis confirmed a direct interaction between LUT and peroxisome proliferator-activated receptor gamma (PPARγ). By using the PPARγ antagonist GW9662, we demonstrated that LUT-driven protection, both in vivo and in vitro, resulted from targeting PPARγ. First, LUT-induced Arg-1+ microglia were no longer detected when PPARγ was blocked. Next, LUT-mediated inhibition of the NLRP3 inflammasome and downregulation of pro-inflammatory cytokine production were reversed by the inhibition of PPARγ. Finally, the protective effects of LUT, which attenuated the microglial engulfment of synapses and prevented apparent synapse loss in the hippocampus of CRS-exposed mice, were eliminated by blocking PPARγ. In conclusion, this study showed that LUT ameliorates CRS-induced depressive-like behaviors by promoting the Arg-1+ microglial phenotype through a PPARγ-dependent mechanism, thereby alleviating microglial pro-inflammatory responses and reversing microglial phagocytosis-mediated synapse loss.

Transcriptomic Profile of the Male Rat Hypothalamus and Nucleus Accumbens After Paroxetine Treatment and Withdrawal: Possible Causes of Sexual Dysfunction

Paroxetine, a selective serotonin reuptake inhibitor (SSRI), may induce sexual dysfunction during treatment and upon discontinuation. The mechanisms involved have been poorly explored so far. We have analyzed, by RNA sequencing, the whole transcriptomic profile in the hypothalamus and nucleus accumbens (NAc) (two brain regions involved in sexual behavior) of male rats daily treated for 2 weeks with paroxetine (T0) and at 1 month of withdrawal (T1). Data here reported show seven differentially expressed genes (DEGs) at T0 and 1 at T1 in the hypothalamus and 245 at T0 and 6 at T1 in the NAc. In addition, Gene-Set Enrichment, Gene Ontology, and Reactome analyses confirm that inflammatory signature and immune system activation were present at T0 in both brain areas. Considering that inflammation is generally associated with depression and that no paradigms inducing the pathology were here applied, these SSRI pro-depressive effects should be considered in patients without a clear indication of depression. Moreover, DEGs related to neurotransmitters with a role in sexual behavior and the reward system, such as dopamine (e.g., sialyltransferase 8B-ST8SIA3), glutamate (e.g., glutamate receptor ionotropic delta-2-GRID2) and GABA (e.g., glutamate decarboxylase type 2-GAD2) or associated with neurexin and neuroligin pathways and brain-derived neurotrophic factor (BDNF) signaling, were reported to be dysregulated in the NAc, further confirming dysfunction in this brain area. Interestingly, the analysis of DEGs altered at T1 in the NAc confirms the persistence of some of these side effects providing further information for post-SSRI sexual dysfunction (PSSD) etiopathogenesis.

Salience network resting state functional connectivity during airway inflammation in asthma: A feature of mental health resilience?

BACKGROUND

Inflammation is an established contributor to the pathophysiology of depression and the prevalence of depression in those with chronic inflammatory disease is two- to four-fold higher than the general population. Yet little is known about the neurobiological changes that confer depression or resilience to depression, that occur when episodes of heightened inflammation are frequent or span many years.

METHODS

We used an innovative combination of longitudinal resting state functional magnetic resonance imaging coupled to segmental bronchial provocation with allergen (SBP-Ag) to assess changes in resting state functional connectivity (rsFC) of the salience network (SN) caused by an acute inflammatory exacerbation in twenty-six adults (15 female) with asthma and varying levels of depressive symptoms. Eosinophils measured in bronchoalveolar lavage fluid and blood provided an index of allergic inflammation and the Beck Depression Inventory provided an index of depressive symptoms.

RESULTS

We found that in those with the highest symptoms of depression at baseline, SN rsFC declined most from pre- to post-SBP-Ag in the context of a robust eosinophilic response to challenge, but in those with low depressive symptoms SN rsFC was maintained or increased, even in those with the most pronounced SBP-Ag response.

CONCLUSIONS

Thus, the maintenance of SN rsFC during inflammation may be a biomarker of resilience to depression, perhaps via more effective orchestration of large-scale brain network dynamics by the SN. These findings advance our understanding of the functional role of the SN during inflammation and inform treatment recommendations for those with comorbid inflammatory disease and depression.

Is There such a Thing as Post-Viral Depression?: Implications for Precision Medicine

Viral infections are increasingly recognized as triggers for depressive disorders, particularly following the SARS-CoV-2 pandemic and the rise of long COVID. Viruses such as Herpes Simplex Virus (HSV), Epstein-Barr Virus (EBV), Cytomegalovirus (CMV), and Human Immunodeficiency Virus (HIV) are linked to depression through complex neurobiological mechanisms. These include immune system dysregulation, chronic inflammation, and neurotransmitter imbalances that affect brain function and mood regulation. Viral activation of the immune system leads to the release of pro-inflammatory cytokines, resulting in neuroinflammation and associated depressive symptoms. Furthermore, specific viruses can disrupt neurotransmitter systems, including serotonin, dopamine, and glutamate, all of which are essential for mood stabilization. The unique interactions of different viruses with these systems underscore the need for virus-specific therapeutic approaches. Current broad-spectrum treatments often overlook the precise neurobiological pathways involved in post-viral depression, reducing their efficacy. This review emphasizes the need to understand these virus-specific interactions to create tailored interventions that directly address the neurobiological effects induced by each type of virus. These interventions may include immunomodulatory treatments that target persistent inflammation, antiviral therapies to reduce the viral load, or neuroprotective strategies that restore neurotransmitter balance. Precision medicine offers promising avenues for the effective management of virus-induced depression, providing patient-specific approaches that address the specific biological mechanisms involved. By focusing on the development of these targeted treatments, this review aims to pave the way for a new era in psychiatric care that fully addresses the root causes of depression induced by viral infections.

Comparative transcriptional analyses of the striatum in the chronic social defeat stress model in C57BL/6J male mice and the gut microbiota-dysbiosis model in Kumming mice

Depression is a complex disorder with multiple contributing factors, and chronic stress has previously been recognized as a major causative factor, while gut microbes have also been found to be involved in depression recently. However, gene expression in depression models with different etiologies is unclear. Here, we compared the transcriptomes of the striatum in chronic social defeat stress (CSDS) model of C57BL/6J male mice and fecal microbiota transplant (FMT) model of Kumming male mice. We found that the proportion of shared differentially expressed genes (DEGs) between the two models was only 24 %. The specific DEGs of FMT model were enriched in immune and inflammatory, and are associated with changes in vascular and ciliated ependymal cells. The specific DEGs of CSDS model were enriched in neuron and synapse. The results of network analysis suggested the expression patterns and biological function of depressive-like behaviors-related modules in the two models are different. Further, the alternative splicing events of CSDS are more than FMT. Our results suggested models of depression induced by different etiologies differ significantly in gene expression and biological function. Our study also suggested us to pay attention to the characteristics of models of depression of different etiologies and provided a more comprehensive understanding of the heterogeneity of depression.

Acute and chronic effects of physical exercise in inflammatory biomarkers in people with depression: A systematic review with meta-analysis

People with depression have increased levels of pro-inflammatory cytokines compared to healthy subjects. Physical exercise can alleviate depressive symptoms and has anti-inflammatory properties. The aim of this study was to identify the effects of exercise on inflammatory biomarkers in people with depression. Clinical trials evaluating the acute and chronic effects of exercise on inflammatory biomarkers in adults with clinical depression were included. The search was conducted on the following databases: PubMed, Embase, Web of Science, PsycINFO, and SPORTDiscus. The risk of bias was assessed with the "Risk of bias in randomized trials" (RoB2) tool. Random effects meta-analyses estimated the acute and chronic effects of exercise for each marker separately. Heterogeneity was estimated with the l2 test. A total of 10 studies (497 participants) were included. No significant acute effects interleukins (IL)-6, IL-10, and IL-8 levels were found. Chronically, exercise increased the levels of TNF-α (Standardized Mean Difference = 0.296; 0.03-0.562, p = 0.029). No chronic effects were found for IL-6 and IL-1B. Overall, 90% of the studies had a moderate or high risk of bias. Exercise seems to promote a small increase in TNF-α, but literature is scarce and with a high risk of bias.

The association between lipid accumulation products and depression in U.S. adults: A cross-sectional study from NHANES 2005-2018

OBJECTIVE

The purpose of this study was to investigate the correlation between lipid accumulation products (LAP) and depression among adults in the United States.

METHODS

We analyzed data from 13,051 persons participating in the NHANES 2005-2018 cycle. The LAP index was calculated using the waist circumference (WC) and serum triglyceride (TG) levels, which reflect lipid toxicity. Participants who scored ≥10 on the Patient Health Questionnaire-9 (PHQ-9) were considered depressed. Multivariate logistic regression analyses were conducted to explore the association between the LAP index and depression. Subgroup analysis was also conducted to identify sensitive populations. Smoothed curve fitting and generalized additive model (GAM) regression were performed to verify the association between the LAP index and depression.

RESULTS

After adjusting for all potential confounders, the risk of depression increased with increasing LAP index (odds ratio [OR]=1.0011, 95% confidence interval [CI]= 1.0001-1.0021). Compared to participants in LAP quartile 1, participants in LAP quartile 3 exhibited the highest risk for depression (OR=1.43, 95% CI: 1.03-1.99). Subgroup analysis demonstrated a stronger association between the LAP index and depression in men (OR= 1.002, 95% CI= 1.001-1.004) and in those with hypertension (OR=1.002, 95% CI=1.000-1.003). Additionally, smoothed curve fitting and GAM regression demonstrated a positive linear correlation between the LAP index and depression.

CONCLUSIONS

These findings suggest that individuals with a higher LAP index may be at greater risk for depression, particularly among men and those with hypertension. Further studies are required to confirm these findings.

Associations between phenols, parabens, and phthalates and depressive symptoms: The role of inflammatory markers and bioinformatic insights

Phenols, parabens, and phthalates are commonly found in consumer products, yet there is limited research on their individual and combined effects on depressive symptoms, particularly regarding the role of inflammation in these associations. This study aimed to evaluate these effects and explore potential molecular mechanisms, with a focus on inflammation as a mediator. We conducted a cross-sectional analysis involving 2766 adult participants from the National Health and Nutrition Examination Survey (NHANES) 2013-2016. Urine samples were analyzed for 15 chemicals, including 3 phenols, 2 parabens, and 10 phthalates. Depressive symptoms were assessed using the Patient Health Questionnaire-9 (PHQ-9). Statistical analyses included linear regression, restricted cubic splines, Bayesian Kernel Machine Regression and quantile g-computation models to investigate the relationships between chemical exposures and depressive symptoms. Additionally, mediation analysis was employed to explore the potential role of inflammation (immune cells, CRP, NLR) in these associations. The underlying molecular mechanisms were analyzed using bioinformatic approaches. Notably, BPA, MECPP, MEHHP, MiBP and MBP were found to be positively associated with depressive symptoms among females. Besides, BPA was the most significant positive contributor to the effect in the context of the chemical mixture, while the overall mixture effect was relatively weak. Furthermore, WBC were found to mediate a marginal portion (4 %) of the potential effects of MBP on depressive symptoms. The 15 genes identified are primarily involved in neurotransmission, mood regulation, and stress response. Further research is needed to elucidate the mechanisms underlying the observed associations.

Lateral habenula IL-10 controls GABAA receptor trafficking and modulates depression susceptibility after maternal separation

Maternal separation (MS), a form of early life adversity, increases the risk of psychiatric disorders in adulthood by intricately linking cytokines and mood-regulating brain circuits. The Lateral Habenula (LHb) encodes aversive experiences, contributes to negative moods, and is pivotal in depression development. However, the precise impact of MS on LHb cytokine signaling and synaptic plasticity remains unclear. We reported that adolescent MS offspring mice displayed susceptibility to depression behavioral phylotypes, with neuronal hyperactivity and an imbalance in pro-inflammatory and anti-inflammatory cytokines in the LHb. Moreover, the decreased IL-10 level negatively correlated with depressive-like behaviors in susceptible mice. Functionally, LHb IL-10 overexpression restored decreased levels of PI3K, phosphorylated AKT (pAKT), gephyrin, and membrane GABAA receptor proteins while reducing abnormally elevated GSK3β and Fos expression, rescuing the MS-induced depression. Conversely, LHb neuronal IL-10 receptor knockdown in naive mice increased Fos expression and elicited depression-like symptoms, potentially through impaired membrane GABAA receptor trafficking by suppressing the PI3K/pAKT/gephyrin cascades. Hence, this work establishes a mechanism by which MS promotes susceptibility to adolescent depression by impeding the critical role of IL-10 signaling on neuronal GABAA receptor function.

Association between allostatic load and depression in patients with sleep disorders: Evidence from the National Health and Nutrition Examination Survey (NHANES)

OBJECTIVE

Allostatic load (AL) is an indicator of the cumulative wear and tear on the body's physiological systems that can predict onset of a range of health problems. However, the relationship between AL and depression in patients with sleep disorders is unclear. This study explored the association between AL and depression in patients with sleep disorders.

METHODS

Using data from the 2015-2016 National Health and Nutrition Examination Survey, a total of 4618 adults aged 18 years and older in the United States were included in this cross-sectional analysis. AL was calculated using nine biological markers, with a score of ≥3 indicating a high level. Depression was assessed using the Patient Health Questionnaire-9 (PHQ-9), with a score of ≥10 indicating risk for depression. Logistic regression models were employed to analyze the relationship between AL and depression.

RESULTS

Among the 1309 participants diagnosed with sleep disorders, 212 (16.2%) were identified as being at risk for depression on the PHQ-9. A total of 55.2% (n = 117) of depressed persons had high AL levels. In the unadjusted model, AL levels were associated with depression in those with sleep disorders (OR=1.53, 95% CI = 1.14-2.05, p < 0.01). This relationship remained significant in the adjusted model (OR=1.52, 95% CI=1.11-2.10, p < 0.05), after controlling for potential confounders.

CONCLUSION

High AL levels in patients with sleep disorders were positively associated with depression, indicating that elevated AL may increase the risk of depression in this population, or alternatively, depression may increase the risk of AL.

No Effects of Omega-3 Supplementation on Kynurenine Pathway, Inflammation, Depressive Symptoms, and Stress Response in Males: A Placebo-Controlled Trial

Background: Increased inflammation and heightened physiological stress reactivity have been associated with pathophysiology of depressive symptoms. The underlying biological mechanisms by which inflammation and stress may influence neurogenesis are changes in the kynurenine (KYN) pathway, which is activated under stress. Supplementation with n-3 polyunsaturated fatty acids (n-3 PUFAs) has anti-inflammatory properties and can increase stress resilience. Whether n-3 PUFAs alter KYN stress response is unknown. Objectives: This placebo-controlled study investigated the effect of n-3 PUFAs on KYN metabolism, inflammation, depressive symptoms, and mood. Moreover, stress-induced changes following a laboratory stressor have been assessed. Methods: In this placebo-controlled study, 47 healthy male adults received either 4 g n-3 PUFAs per day (Omega-3 group) or a placebo (Placebo group) for 12 weeks. Results: A significant group-by-time interaction was found for the inflammatory markers gp130 (F = 7.07, p = 0.011), IL-6R alpha (F = 10.33, p = 0.003), and TNF_RI (F= 10.92, p = 0.002). No significant group-by-time interactions were found for KYN metabolites, depressive symptoms, and mood (except for Hedonic tone (F = 6.50, p = 0.014)), nor for stress-induced changes in KYN metabolites and mood following a laboratory stressor. Conclusions: Overall, increased n-3 PUFA levels in healthy men ameliorate inflammatory markers but do not ameliorate KYN metabolism, depressive symptoms, mood, or KYN metabolism and mood following a stress induction. This study was registered at ClinicalTrials.gov with the identifier NCT05520437 (30/08/2022 first trial registration).

Rehmannia glutinosa DC.-Lilium lancifolium Thunb. in the treatment of depression: a comprehensive review and perspectives

Background

In recent years, the incidence of depression, recognized as a serious psychological disorder, has escalated rapidly. Rehmannia glutinosa DC. (Scrophulariaceae; Rehmanniae Radix, Crude drug) and Lilium lancifolium Thunb. (Liliaceae; Lilii bulbus, Crude drug) constitute a classic anti-depressant combination, exhibiting pharmacological effects that include anti-depressive, anti-anxiety, and anti-inflammatory properties. Current clinical studies have demonstrated that Baihe Dihuang Decoction, a traditional Chinese herbal compound, is effective in treating depression. However, the majority of scholars have predominantly examined Rehmannia glutinosa and Lilium in isolation, and a comprehensive elucidation of their principal active metabolites and pharmacological mechanisms remains lacking.

Methods

A comprehensive literature search was conducted as of 29 September 2024, utilizing databases such as PubMed, CNKI, Wanfang Data, Baidu Scholar, and Google Scholar. Additionally, classical texts on Chinese herbal medicine, the Chinese Pharmacopoeia, as well as doctoral and master's theses, were included in the collected materials. The search employed specific terms including "R. glutinosa," "Lilium," "Baihe Dihuang decoction," "application of Baihe Dihuang decoction," "pathogenesis of depression," and "pharmacological action and mechanism of depression.

Results

This paper reviewed the traditional applications and dosages of the R. glutinosa-Lilium as documented in Chinese medical classics, thereby establishing a foundation for the contemporary development and clinical application of the classical formula Baihe Dihuang Decoction. Additionally, recent years have seen a comprehensive review of the pharmacological effects and mechanisms of R. glutinosa-Lilium and its principal metabolites in the context of depression.

Conclusion

This paper has reviewed the active metabolites of R. glutinosa-Lilium and demonstrated its efficacy in the treatment of depression, as well as its role in modulating the underlying mechanisms of the disorder. The findings aim to serve as a reference for further research into the mechanisms of depression, its clinical applications, and the development of novel therapeutic agents.

The association between the ten-year trajectory of multimorbidity and depressive symptoms among the middle-aged and older adults: Results from the China Health and Retirement Longitudinal Study

BACKGROUND

Despite the established link between chronic conditions and depressive symptoms in recent decades, research into the temporal dynamics between multimorbidity and the occurrence of depressive symptoms remains scarce.

METHODS

A total of 15,882 Chinese middle-aged and older adults with 63,246 observations from the China Health and Retirement Longitudinal Study were included in the present study. Depressive symptoms were evaluated using a 10-item CESD scale, with a threshold set at 12 points. Group-based trajectory modeling was used to examine the multimorbidity developmental trajectories. The risk of depressive symptoms was analyzed using mixed effect logistic regression models.

RESULTS

Among the final included 15,896 participants, 37.6 % reported states of multimorbidity, and 25.7 % were detected as depressive symptoms. In the fully adjusted model, those with multimorbidity were 2.36 (2.24 to 2.49) times more likely to present depressive symptoms, and the likelihood increased 1.38 (1.36 to 1.40) times with each additional chronic condition. Four distinct multimorbidity trajectory groups were identified: no-new-condition group (32.6 %), slow growth group (42.9 %), steady growth group (19.7 %), and rapid growth group (4.9 %). Compared to the no-new-condition group, the likelihood of developing depressive symptoms was greater in the subsequent three groups, with ORs of 1.53 (1.39 to1.71), 2.54 (2.24 to 2.89), and 4.40 (3.62 to 5.34), respectively.

CONCLUSION

Our results highlight the substantial health effects of accumulating multimorbidity on depressive symptoms, showing a direct link between risk and accumulation rate. We urge focusing on depressive symptoms in those with multimorbidity to tackle the significant healthcare challenges arising from concurrent physical and mental health issues.

Mood disorders and 5-HTR2A genetic variants - the moderator effect of inflammation on expression of affective polarity phenotype

BACKGROUND

Although repeatedly confirmed, the molecular nature of gene-environment (GxE) interactions has rarely been investigated in the clinical context of mood disorders. This study assesses the relationship between HTR2A genetic variants and the modulatory effect of inflammation in a collective cohort of patients with major depressive disorder (MDD) and bipolar disorder (BD), as a unified group with two distinct phenotypes.

METHODS

The study included 138 patients with acute mood episodes (BD = 83; MDD = 55). HTR2A rs6313 and rs6314 genotyping was performed while measuring platelet-derived indicators of inflammation (platelet count (PLT), mean platelet volume (MPV), plateletcrit, and platelet distribution width) and the MPV/PLT ratio.

RESULTS

The HTR2A rs6313 variant is a significant predictor of the polarity phenotype in mood disorders, with the MPV/PLT ratio moderating this relationship, but only under low-inflammatory conditions. In more pronounced inflammatory states, genetic influences lose their predictive role.

CONCLUSIONS

To our knowledge, this is the first study to investigate the complex interplay between platelet-derived indicators of inflammation and HTR2A variants in the context of mood disorders. Without pro-inflammatory conditions, mood disorders seem to be more genetically determined. Under pro-inflammatory conditions, phenotypic presentation is less dependent on genetic factors. GxE interactions in mood disorders are multifaceted, context-dependent and relevant for assessing their clinical presentation and course.

Neuropsychiatric symptoms of patients two years after experiencing severe COVID-19: A mixed observational study

BACKGROUND

The impact of SARS-CoV-2 infection (COVID-19) on mental health has not been extensively studied in the medium and long term. This study assessed how clinical, biological, and social factors affect mental health in patients who recovered from severe COVID-19. The evaluation was done 90 days after hospital discharge and followed up at 12 and 24 months.

METHODS

A retrospective-prospective cohort mixed observational study was conducted on patients over 18 years of age who required hospitalization in Internal Medicine or ICU for severe COVID-19 pneumonia during 2020 and 2021. Demographic information, clinical variables, and data for the scales were obtained from electronic medical records and telephone interviews. For comparisons of the different variables in each clinical variable (insomnia, depression, anxiety), the Student's t-test for independent samples has been used (normal distribution); otherwise, the Mann-Whitney test will be used. All tests and intervals will be performed with a confidence level of 95. Fisher's exact or Pearson's Chi-square test has been used as appropriate for qualitative variables.

RESULTS

201 patients were recruited. 37.3% presented insomnia, 22.4% anxiety, and 21.4% depressive symptoms. A direct association was established between female sex and depressive symptoms. Psychotropic history, fatigue, and C-reactive protein levels (CRP) were correlated with depression. Anosmia and ageusia, CRP, cognitive symptoms, and dyspnea predicted insomnia. Sex, orotracheal intubation (OTI), pain, fatigue, mental health history, and academic level were independent predictors of anxiety. High percentages of depressive, anxiety, and insomnia symptoms were detected in the second month after discharge and persisted at 12 and 24 months. The fatigue variable maintained a significant relationship with depressive symptoms at 2, 12 and 24 months. A possible limitation could be recall bias in retrospective data collection.

CONCLUSIONS

This is a novel study to follow up on mental health for two years in patients with severe COVID-19. Clinical, biological, and psychosocial variables could be predictors of depressive symptoms, anxiety, and insomnia. The psychiatric symptoms persisted throughout the 2-year follow-up. These findings are critical for the follow-up of these patients and open the possibility of further studies in the medium and long term.

Molecular Modeling and In Vitro Functional Analysis of the RGS12 PDZ Domain Variant Associated with High-Penetrance Familial Bipolar Disorder

Bipolar disorder's etiology involves genetics, environmental factors, and gene-environment interactions, underlying its heterogeneous nature and treatment complexity. In 2020, Forstner and colleagues catalogued 378 sequence variants co-segregating with familial bipolar disorder. A notable candidate was an R59Q missense mutation in the PDZ (PSD-95/Dlg1/ZO-1) domain of RGS12. We previously demonstrated that RGS12 loss removes negative regulation on the kappa opioid receptor, disrupting basal ganglia dopamine homeostasis and dampening responses to dopamine-eliciting psychostimulants. Here, we investigated the R59Q variation in the context of potential PDZ domain functional alterations. We first validated a new target for the wildtype RGS12 PDZ domain-the SAPAP3 C-terminus-by molecular docking, surface plasmon resonance (SPR), and co-immunoprecipitation. While initial molecular dynamics (MD) studies predicted negligible effects of the R59Q variation on ligand binding, SPR showed a significant reduction in binding affinity for the three peptide targets tested. AlphaFold2-generated models predicted a modest reduction in protein-peptide interactions, which is consistent with the reduced binding affinity observed by SPR, suggesting that the substituted glutamine side chain may weaken the affinity of RGS12 for its in vivo binding targets, likely through allosteric changes. This difference may adversely affect the CNS signaling related to dynorphin and dopamine in individuals with this R59Q variation, potentially impacting bipolar disorder pathophysiology.

Independent and joint influence of depression and advanced lung cancer inflammation index on mortality among individuals with chronic kidney disease

Background

The combined effect of depression and nutritional-inflammatory status on mortality in the chronic kidney disease (CKD) population is unclear.

Methods

We prospectively analyzed 3,934 (weighted population: 22,611,423) CKD participants from the National Health and Nutrition Examination Survey (2007-2018). Depression and nutritional-inflammatory status were assessed with Patient Health Questionnaire 9 (PHQ-9) and Advanced Lung Cancer Inflammation Index (ALI), respectively. Weighted multivariate COX regression models, restricted cubic splines (RCS) models, and stratified analyses were used to investigate the association of PHQ-9 scores and ALI with all-cause mortality.

Results

During a median follow-up of 5.8 years (interquartile range 3.4-8.6 years), a total of 985 patients died (25.0%). Each point increase in a patient's PHQ-9 score increased the risk of all-cause mortality by 4% (HR, 1.04; 95% CI, 1.02-1.06; p < 0.001), in the full adjusted model. However, an increase in ALI levels was associated with a decreased risk. HRs (95% CI) of 0.76 (0.65-0.90), 0.70 (0.57-0.86), and 0.51 (0.41-0.64) in the Q2, Q3, and Q4 of ALI compared with the Q1 of ALI, respectively. In addition, the joint analysis showed that CKD patients without depression and with higher ALI were associated with a reduced risk of all-cause mortality. Namely, patients in the highest ALI group (Q4) without depression had the lowest risk (HR, 0.32; 95% CI, 0.21-0.48). Furthermore, this combined effect was consistent across all subgroups, and no significant interaction was found (p > 0.05 for interaction).

Conclusion

In a nationally representative sample of US patients with CKD, coexisting depression and poorer nutrition-inflammation were associated with a significantly increased risk of all-cause mortality.

The Protective Effects of Polygala tenuifolia and Tenuifolin on Corticosterone-Evoked Ferroptosis, Oxidative Stress, and Neuroinflammation: Insights from Molecular Dynamics Simulations and In Vitro Experiments

Excessive stress is a well-established contributor to neurological damage, insomnia, and depression, imposing a significant burden on individuals and society. This underscores the urgent need for effective stress-relief strategies. The main purpose of this study was to explore the protective effects of Polygala tenuifolia (PT) and its bioactive compound, tenuifolin, against corticosterone-induced neurotoxicity, with a focus on ferroptosis, oxidative stress, and neuroinflammation. Both PT extracts and tenuifolin mitigated corticosterone-induced cellular damage. Tenuifolin reversed the corticosterone-induced dysregulation of ferroptosis-associated proteins, such as SLC7A11, GPX4, and Nrf2, leading to a marked reduction in ferroptosis levels. Molecular dynamics simulations revealed that corticosterone significantly altered the conformation and binding energy of the SLC7A11/SLC3A2 complex, critical for ferroptosis regulation. These changes were reversed by tenuifolin. Additionally, tenuifolin alleviated corticosterone-induced oxidative stress and neuroinflammation, both of which accelerated ferroptosis. In conclusion, these results indicate that tenuifolin attenuates corticosterone-induced neurotoxicity by modulating ferroptosis, oxidative stress, and neuroinflammation. This study provides a theoretical foundation for the application of PT and tenuifolin in stress-induced nerve damage.

The role of enteric nervous system and GDNF in depression: Conversation between the brain and the gut

Depression is a debilitating mental disorder that causes a persistent feeling of sadness and loss of interest. Approximately 280 million individuals worldwide suffer from depression by 2023. Despite the heavy medical and social burden imposed by depression, pathophysiology remains incompletely understood. Emerging evidence indicates various bidirectional interplay enable communication between the gut and brain. These interplays provide a link between intestinal and central nervous system as well as feedback from cortical and sensory centers to enteric activities, which also influences physiology and behavior in depression. This review aims to overview the significant role of the enteric nervous system (ENS) in the pathophysiology of depression and gut-brain axis's contribution to depressive disorders. Additionally, we explore the alterations in enteric glia cells (EGCs) and glial cell line-derived neurotrophic factor (GDNF) in depression and their involvement in neuronal support, intestinal homeostasis maintains and immune response activation. Modulating ENS function, EGCs and GDNF level could serve as novel strategies for future antidepressant therapy.

Association Between Gallstones and Depressive Symptoms: Results from NHANES and Mendelian Randomization Study

Purpose

Prior research has suggested a correlation between gallstones and depressive symptoms, yet the specifics of this relationship remain unclear. This study aims to explore the association between gallstones and depressive symptoms among adults.

Patients and Methods

Initially, we conducted a cross-sectional study using data from the National Health and Nutrition Examination Survey (NHANES) 2017 - March 2020. After propensity score matching (PSM) for participants with gallstones and those without gallstones, multivariate logistic regression analysis was used to explore the potential association between gallstones and depressive symptoms. This was followed by Mendelian randomization (MR) analysis to further elucidate the causal relationship between them. Using the genome-wide association study database, we extracted instrumental variables and performed bidirectional univariate and multivariate MR analyses.

Results

In the cross-sectional study of NHANES 2017 - March 2020, 835 pairs of participants with comparable characteristics, both with and without gallstones, were identified after PSM. The multivariate adjusted logistic regression analyses revealed a significant association between gallstones and depressive symptoms [fully adjusted model: OR=1.821 (95% CI, 1.181-2.808), P=0.007]. Subsequent MR analyses further clarified the causal relationship, indicating that genetically determined gallstones significantly increase the risk of developing depressive symptoms [forward univariate MR analysis: OR=1.04 (95% CI, 1.01-1.06), P=0.002; multivariate MR analysis: OR=1.03 (95% CI, 1.01-1.05), P=0.009], with no evidence of reverse causation [inverse univariate MR analysis: OR=1.28 (95% CI, 0.90-1.83), P=0.17].

Conclusion

Gallstones are a risk factor for depressive symptoms among adults. Hence, we recommend timely depression screening for patients diagnosed with gallstones, facilitating early detection and effective treatment of depressive symptoms, thus alleviating its impact on both individuals and society.

The antipsychotic chlorpromazine reduces neuroinflammation by inhibiting microglial voltage-gated potassium channels

Neuroinflammation, the result of microglial activation, is associated with the pathogenesis of a wide range of psychiatric and neurological disorders. Recently, chlorpromazine (CPZ), a dopaminergic D2 receptor antagonist and schizophrenia therapy, was proposed to exert antiinflammatory effects in the central nervous system. Here, we report that the expression of Kv1.3 channel, which is abundant in T cells, is upregulated in microglia upon infection, and that CPZ specifically inhibits these channels to reduce neuroinflammation. In the mouse medial prefrontal cortex, we show that CPZ lessens Kv1.3 channel activity and reduces proinflammatory cytokine production. In mice treated with LPS, we found that CPZ was capable of alleviating both neuroinflammation and depression-like behavior. Our findings suggest that CPZ acts as a microglial Kv1.3 channel inhibitor and neuroinflammation modulator, thereby exerting therapeutic effects in neuroinflammatory psychiatric/neurological disorders.

New Evidence for the Role of the Blood-Brain Barrier and Inflammation in Stress-Associated Depression: A Gene-Environment Analysis Covering 19,296 Genes in 109,360 Humans

Mounting evidence supports the key role of the disrupted integrity of the blood-brain barrier (BBB) in stress- and inflammation-associated depression. We assumed that variations in genes regulating the expression and coding proteins constructing and maintaining this barrier, along with those involved in inflammation, have a predisposing or protecting role in the development of depressive symptoms after experiencing severe stress. To prove this, genome-by-environment (GxE) interaction analyses were conducted on 6.26 M SNPS covering 19,296 genes on PHQ9 depression in interaction with adult traumatic events scores in the UK Biobank (n = 109,360) in a hypothesis-free setup. Among the 63 genes that were significant in stress-connected depression, 17 were associated with BBB, 23 with inflammatory processes, and 4 with neuroticism. Compared to all genes, the enrichment of significant BBB-associated hits was 3.82, and those of inflammation-associated hits were 1.59. Besides some sex differences, CSMD1 and PTPRD, encoding proteins taking part in BBB integrity, were the most significant hits in both males and females. In conclusion, the identified risk genes and their encoded proteins could provide biomarkers or new drug targets to promote BBB integrity and thus prevent or decrease stress- and inflammation-associated depressive symptoms, and possibly infection, e.g., COVID-19-associated mental and neurological symptoms.

Bidirectional relationship between diabetes mellitus and depression: Mechanisms and epidemiology

Diabetes mellitus and depression exhibit a complex bidirectional relationship that profoundly impacts patient health and quality of life. This review explores the physiological mechanisms, including inflammation, oxidative stress, and neuroendocrine dysregulation, that link these conditions. Psychosocial factors such as social support and lifestyle choices also contribute significantly. Epidemiological insights reveal a higher prevalence of depression among diabetics and an increased risk of diabetes in depressed individuals, influenced by demographic variables. Integrated management strategies combining mental health assessments and personalized treatments are essential. Future research should focus on longitudinal and multi-omics studies to deepen understanding and improve therapeutic outcomes.

Novel therapeutic targets for major depressive disorder related to oxidative stress identified by integrative multi-omics and multi-trait study

Oxidative stress (OS) is strongly implicated in the pathophysiology of major depressive disorder (MDD) but the molecular mechanisms remain largely unknown. The purpose of this study is to identify genes related to both OS and MDD, and further to evaluate the utility of these genes as diagnostic markers and potential treatment targets. We searched datasets related to MDD from the Gene Expression Omnibus (GEO) database for differentially expressed genes (DEGs) also related to OS according to GeneCards. Bioinformatics analyses and machine learning algorithms were used to identify hub genes mediating OS-MDD interactions. A summary data-based Mendelian randomization (SMR) approach was employed to identify possible causal genes for MDD from blood tissue eQLT data. These investigations identified 32 genes mediating OS-MDD interactions, while SMR analysis identified KCNE1 (OR = 1.057, 95%CI = 1.013-1.102, P value = 0.010), MAPK3 (OR = 1.023, 95%CI = 1.004-1.043, P value = 0.020), and STIP1 (OR = 0.792, 95%CI = 0.641-0.979, P value = 0.031) as OS-related causal genes for MDD. These genes may thus serve as useful diagnostic markers and potential therapeutic targets.

HMGB1, an evolving pleiotropic protein critical for cellular and tissue homeostasis: Role in aging and age-related diseases

Aging is a universal biological process characterized by a progressive, cumulative decline in homeostatic capabilities and physiological functions, which inevitably increases vulnerability to diseases. A number of molecular pathomechanisms and hallmarks of aging have been recognized, yet we miss a thorough understanding of their complex interconnectedness. This review explores the molecular and cellular mechanisms underlying human aging, with a focus on the multiple roles of high mobility group Box 1 protein (HMGB1), the archetypal damage-associated molecular pattern (DAMP) molecule. In the nucleus, this non-histone chromatin-associated protein functions as a DNA chaperone and regulator of gene transcription, influencing DNA structure and gene expression. Moreover, this versatile protein can translocate to the cytoplasm to orchestrate other processes, such as autophagy, or be unconventionally secreted into the extracellular environment, where it acts as a DAMP, combining inflammatory and regenerative properties. Notably, lower expression of HMGB1 within the cell and its heightened extracellular release have been associated with diverse age-associated traits, making it a suitable candidate as a universal biomarker of aging. In this review, we outline the evidence implicating HMGB1 in aging, also in light of an evolutionary perspective on its functional pleiotropy, and propose critical issues that need to be addressed to gauge the value of HMGB1 as a potential biomarker across age-related diseases and therapeutic target to promote healthy longevity.

Vasopressin drives aberrant myeloid differentiation of hematopoietic stem cells, contributing to depression in mice

Psychological stress is often linked to depression and can also impact the immune system, illustrating the interconnectedness of mental health and immune function. Hematopoietic stem cells (HSCs) can directly sense neuroendocrine signals in bone marrow and play a fundamental role in the maintenance of immune homeostasis. However, it is unclear how psychological stress impacts HSCs in depression. Here, we report that neuroendocrine factor arginine vasopressin (AVP) promotes myeloid-biased HSC differentiation by activating neutrophils. AVP administration increases neutrophil and Ly6Chi monocyte production by triggering HSCs that rely on intrinsic S100A9 in mice. When stimulated with AVP, neutrophils return to the bone marrow and release interleukin 36G (IL-36G), which interacts with interleukin 1 receptor-like 2 (IL-1RL2) on HSCs to produce neutrophils with high Elane expression that infiltrate the brain and induce neuroinflammation. Together, these findings define HSCs as a relay between psychological stress and myelopoiesis and identify the IL-36G-IL-1RL2 axis as a potential target for depression therapy.