Ozone causes depressive-like response through PI3K/Akt/GSK3β pathway modulating synaptic plasticity in young rats

Polysaccharides from Scrophularia ningpoensis Hemsl. improve reserpine-induced depression-like behavior by inhibiting HTR2A/HTR2C mediated AKT/GSK3β/β-catenin/CBP/BDNF signalling

Scrophularia ningpoensis Hemsl. is a traditional Chinese medicine used to regulate blood sugar levels, immunity, etc. We previously isolated polysaccharides from S. ningpoensis Hemsl. (SNPS) and innovatively observed that SNPS exhibit antidepressant properties; however, the underlying mechanism is still unclear. Here, we employed network pharmacology to predict the potential targets and antidepressant mechanism of SNPS. Accordingly, we detected the effects of SNPS on monoamine neurotransmitter synthesis, metabolism, receptor expression and signal transduction in reserpine (RES)-treated mice using ELISA, HPLC-electrochemistry, metabonomics, Golgi-Cox staining and Western blotting. Finally, the mechanism of SNPS on key targets (HTR2A and HTR2C) was verified in vivo and in vitro. Results showed that SNPS ameliorated depression by restoring monoamine neurotransmitter homeostasis and hippocampal neurogenesis. SNPS reversed the depletion of 5-HT, NE and DA by activating the tryptophan (Trp)/5-HT and tyrosine (Tyr)/DA/NE metabolic pathways. SNPS decreased HTR2A and HTR2C contents, leading to the phosphorylation of AKT and GSK3β, followed by increases in β-catenin, CBP and BDNF levels. Mechanistically, SNPS reduced the levels of HTR2A and HTR2C proteins by inhibiting their mRNA transcription, rather than inducing protein degradation. In conclusion, by inhibiting the transcription of HTR2A and HTR2C, SNPS activated the AKT/GSK3β/β-catenin/CBP/BDNF pathway, thereby exerting dose-dependent antidepressant effects.

Adolescent exposure to micro/nanoplastics induces cognitive impairments in mice with neuronal morphological damage and multi-omic alterations

Polystyrene micro/nanoplastics (MPs/NPs) are globally recognized environmental concerns due to their widespread pollution and detrimental effects on physiological functions. However, the neurotoxic effects and underlying mechanisms of MPs/NPs on brain function in adolescents remain incompletely understood. This study investigated the effects of polystyrene MPs/NPs on neurobehavioral function in adolescent mice, utilizing multi-omic analysis and molecular biology assays to explore potential mechanisms. Following oral exposure of MPs (5 μm) or NPs (0.5 μm) at 0.5 mg/day for 4 weeks, NPs induced more severe cognitive impairment in mice than MPs, as assessed by the Morris water maze and Y-maze tests. This impairment might be associated with the neuron loss and neurogenesis inhibition caused by NPs, while dendritic spine loss mediated by MPs in the hippocampus. Furthermore, analysis of hippocampal transcriptome and Western blotting indicated the potential involvement of the PI3K/AKT pathway in NPs-induced neurotoxicity. Meanwhile, exposure to NPs induced more pronounced disruptions in the hippocampal metabolome and gut microbiota, and strong correlations were observed between changes in hippocampal metabolites and gut bacteria. This study elucidated the toxicity mechanism of MPs and NPs in inducing cognitive impairment in adolescent mice, providing insights into their toxicological impacts and potential strategies for intervention.

Ozone: complicated effects in central nervous system diseases

Oxidative stress is closely related to various diseases. Ozone can produce redox reactions through its unique response. As a source of the oxidative stress response, the strong oxidizing nature of ozone can cause severe damage to the body. On the other hand, low ozone concentrations can activate various mechanisms to combat oxidative stress and achieve therapeutic effects. Some animal experiments and clinical studies have revealed the potential medical value of ozone, indicating that ozone is not just a toxic gas. By reviewing the mechanism of ozone and its therapeutic value in treating central nervous system diseases (especially ischemic stroke and Alzheimer's disease) and the toxic effects of ozone, we find that ozone inhalation and a lack of antioxidants or excessive exposure lead to harmful impacts. However, with adequate antioxidants, ozone can transmit oxidative stress signals, reduce inflammation, reduce amyloid β peptide levels, and improve tissue oxygenation. Similar mechanisms to those of possible new drugs for treating ischemic stroke and Alzheimer's disease indicate the potential of ozone. Nevertheless, limited research has restricted the application of ozone. More studies are needed to reveal the exact dose-effect relationship and healing effect of ozone.

An ex vivo model of systemically-mediated effects of ozone inhalation on the brain

Air pollution is associated with increased risk of neurodegenerative and neuropsychiatric conditions. While animal models have increased our understanding of how air pollution contributes to brain pathologies - including through oxidative stress, inflammatory, and stress hormone pathways - investigation of underlying mechanisms remains limited due to a lack of human-relevant models that incorporate systemic processes. Our objective was to establish an ex vivo approach that enables assessment of the roles of plasma mediators in pollutant-induced effects in the brain. As a proof-of-concept for application in the human context, we assessed whether such effects reproduced in vivo responses to pollutant exposure. Primary rat hippocampal neurons and microglia were each treated with plasma collected from rats immediately or 24 h after ozone inhalation (0 or 0.8 ppm) ± pre-treatment with the glucocorticoid synthesis inhibitor metyrapone. Microglia were further challenged with lipopolysaccharide to evaluate modification of inflammatory responses. Plasma from the ozone-exposed group produced transcriptional changes (inflammatory, antioxidant, glucocorticoid-responsive) in neurons, some of which were glucocorticoid-dependent. Ex vivo and hippocampal responses were strongly correlated, establishing the in vivo relevance of the model. Plasma from the ozone-exposed group modified inflammatory responses to lipopolysaccharide challenge in microglia, demonstrating the model's utility to assess functional changes resulting from pollutant exposure. This study establishes that an ex vivo approach can reproduce ozone-induced effects in the brain. The model was sensitive to specific plasma mediators and temporal effects, and enabled assessment of functional responses. This approach may serve to investigate mechanisms underlying effects of pollutants on the human brain.

Clinical value of serum LncRNA MIAT in early diagnosis and prognosis assessment of traumatic brain injury

OBJECTIVE

This study aims to explore the clinical significance of long non-coding RNA, myocardial infarction-associated transcript (MIAT), in patients with traumatic brain injury (TBI).

METHODS

Retrospective inclusion of TBI patients meeting clinical criteria with complete data, alongside healthy controls. RT-qPCR was used to detect the expression of the serum MIAT. Based on the Glasgow Coma Scale (GCS) scores, patients were categorized into mild, moderate, and severe TBI groups. The potential risk factors for severity were examined using logistic regression analysis. The one-year prognosis for TBI was determined using the Glasgow Outcome Scale (GOS) score. The correlation of MIAT levels with GCS scores and GOS scores was determined using Pearson correlation analysis. The effect of MIAT on the severity and poor prognosis was assessed using the receiver operating characteristic curve. Lastly, the dual-luciferase reporter assay confirmed the relationship between the MIAT and miR-221-3p.

RESULTS

110 patients with TBI and 106 healthy controls were included. Serum MIAT levels were strikingly higher in patients with TBI compared to controls, whereas miR-221-3p levels were lower. As the severity of TBI increases, the expression of MIAT gradually elevated. A notable negative correlation was observed between serum MIAT levels and both the GCS and GOS scores. MIAT levels were effective in distinguishing patients with moderate TBI from those with mild or severe TBI, with a sensitivity of 82.35 % and 88.64 % and a specificity of 86.67 % and 86.27 %. Furthermore, elevated MIAT levels, with a sensitivity of 85.00 % and a specificity of 75.56 %, can predict the clinical outcomes of patients with TBI. miR-221-3p levels were negatively correlated with MIAT expression in patients with TBI, and MIAT directly targeted miR-221-3p.

CONCLUSION

Serum MIAT could serve as a diagnostic marker of severity and may predict poor prognosis in patients with TBI. This study proposes fresh perspectives on the pursuit of biomarkers and the management of patients with TBI.

The relationship between air pollution and depression and anxiety disorders - A systematic evaluation and meta-analysis of a cohort-based study

OBJECTIVE

To explore the correlation between air pollution and the onset of depression and anxiety disorders, to draw more comprehensive and integrated conclusions, and to provide recommendations for maintaining mental health and developing policies to reduce mental health risks caused by air pollution.

METHODS

Meta-analysis of cohort study articles exploring the relationship between air pollution and depression or anxiety disorders included in Pubmed, Web Of Science, CNKI, and Wan Fang database before October 31, 2022, and subgroup analysis of the association between air pollution and depression and anxiety disorders regarding the air pollutants studied, the study population, and Publication bias analysis and sensitivity analysis.

RESULTS

A total of 25 articles meeting the criteria were included in this study, including 23 articles examining the relationship between air pollution and depression and 5 articles examining the relationship between air pollution and anxiety disorders. The results of the meta-analysis were based on the type of pollutant and showed that there was a high degree of heterogeneity among the studies on the relationship between air pollution and depression and a significant heterogeneity among the studies on PM2.5 and the risk of anxiety disorders (I2 = 71%, p < .01), so a random-effects model was selected for the analysis. CO, O3, and SO2 and depression onset had combined RR values of 1.10 (1.00, 1.20), 1.06 (0.87, 1.29), 1.17 (1.06, 1.31), 1.19 (0.90, 1.58), 1.03 (0.99, 1.07), and 1.09 (0.97, 1.24), respectively, and PM2.5 and anxiety The combined RR value for morbidity was 1.10 (0.99, 1.22). The results of sensitivity analysis showed that the combined results were stable and reliable. The results of Egger regression method test showed that none of them had significant publication bias (p > .05).

LIMITATION

Combined exposure to air pollutants on depression and anxiety, further studies by other researchers are needed in the future.

CONCLUSIONS

PM2.5 and NO2 exposure, especially long-term exposure, may be associated with the onset of depression, and no association was found for the time being between PM10, CO, O3, SO2 exposure and depression and PM2.5 exposure and anxiety disorders.

Ozone-induced neurotoxicity: In vitro and in vivo evidence

Together with cities in higher-income nations, it is anticipated that the real global ozone is rising in densely populated areas of Asia and Africa. This review aims to discuss the possible neurotoxic pollutants and ozone-induced neurotoxicity: in vitro and in vivo, along with possible biomarkers to assess ozone-related oxidative stress. As a methodical and scientific strategy for hazard identification and risk characterization of human chemical exposures, toxicological risk assessment is increasingly being implemented. While traditional methods are followed by in vitro toxicology, cell culture techniques are being investigated in modern toxicology. In both human and rodent models, aging makes the olfactory circuitry vulnerable to spreading immunological responses from the periphery to the brain because it lacks the blood-brain barrier. The ozone toxicity is elusive as it shows ventral and dorsal root injury cases even in the milder dose. Its potential toxicity should be disclosed to understand further the clear mechanism insights of how it acts in cellular aspects. Human epidemiological research has confirmed the conclusions that prenatal and postnatal exposure to high levels of air pollution are linked to behavioral alterations in offspring. O3 also enhances blood circulation. It has antibacterial action, which may have an impact on the gut microbiota. It also activates immunological, anti-inflammatory, proteasome, and growth factor signaling Prolonged O3 exposure causes oxidative damage to plasma proteins and lipids and damages the structural and functional integrity of the mitochondria. Finally, various studies need to be conducted to identify the potential biomarkers associated with ozone and the brain.

Taselisib moderates neuropathic pain through PI3K/AKT signaling pathway in a rat model of chronic constriction injury

BACKGROUND

Neuropathic pain is a chronic condition commonly caused by inflammation-induced disturbances or lesions of somatosensory functions in the nervous system. The aim of this study was to investigate the effects and mechanisms of Taselisib on chronic constriction injury (CCI)-induced neuropathic pain in rats.

METHODS

The rats were divided into four groups: sham group, sham + Taselisib (10mg/kg orally once a day) group, CCI group, and CCI + Taselisib (10mg/kg orally once a day) group. Pain behavioral tests, recorded by measuring paw withdrawal threshold (PWT) and thermal withdrawal latency (TWL), were conducted on days 0, 3, 7, 14, and 21 after surgery. After testing, the animals were euthanized and spinal dorsal horns were collected. Pro-inflammatory cytokines were quantified using ELISA and qRT-PCR. PI3K/pAKT signaling was assessed using Western blot and immunofluorescence.

RESULTS

PWT and TWL were significantly reduced after CCI surgery, but were successfully increased by Taselisib treatment. Taselisib treatment notably suppressed the upregulation of pro-inflammatory cytokines, including IL-6, IL-1β, and TNF-⍺. Taselisib treatment significantly reduced the elevated phosphorylation of AKT and PI3K induced by CCI.

CONCLUSION

Taselisib can alleviate neuropathic pain by inhibiting the pro-inflammatory response, potentially through the PI3K/AKT signaling pathway.

Research Progress on the Pharmacodynamic Mechanisms of Sini Powder against Depression from the Perspective of the Central Nervous System

Depression is a highly prevalent emotional disorder characterized by persistent low mood, diminished interest, and loss of pleasure. The pathological causes of depression are associated with neuronal atrophy, synaptic loss, and neurotransmitter activity decline in the central nervous system (CNS) resulting from injuries, such as inflammatory responses. In Traditional Chinese Medicine (TCM) theory, patients with depression often exhibit the liver qi stagnation syndrome type. Sini Powder (SNP) is a classic prescription for treating such depression-related syndrome types in China. This study systematically summarized clinical applications and experimental studies of SNP for treatments of depression. We scrutinized the active components of SNP with blood-brain barrier (BBB) permeability and speculated about the corresponding pharmacodynamic pathways relevant to depression treatment through intervening in the CNS. Therefore, this article can enhance our understanding of SNP's pharmacological mechanisms and formula construction for depression treatment. Moreover, a re-demonstration of this classic TCM prescription in the modern-science language is of great significance for future drug development and research.

The ameliorative effects and mechanisms of abscisic acid on learning and memory

Abscisic acid (ABA), a conserved hormone existing in plants and animals, not only regulates blood glucose and inflammation but also has good therapeutic effects on obesity, diabetes, atherosclerosis and inflammatory diseases in animals. Studies have shown that exogenous ABA can pass the blood-brain barrier and inhibit neuroinflammation, promote neurogenesis, enhance synaptic plasticity, improve learning, memory and cognitive ability in the central nervous system. At the same time, ABA plays a crucial role in significant improvement of Alzheimer's disease, depression, and anxiety. Here we review the previous research progress of ABA on the physiological effects and clinical application in the related diseases. By summarizing the biological functions of ABA, we aim to reveal the possible mechanisms of ameliorative function of ABA on learning and memory, to provide a theoretical basis that ABA as a novel and safe drug improves learning memory and cognitive impairment in central system diseases such as aging, neurodegenerative diseases and traumatic brain injury.