Compound essential oils relieve oxidative stress caused by PM2 .5 exposure by inhibiting autophagy through the AMPK/mTOR pathway

Stibene glucoside prevents PM2.5 caused pulmonary fibrosis by Pseudo hypoxia, autophagy and NF-κB signal pathways

Although the association between PM2.5 exposure and pulmonary fibrosis is well-documented, the underlying molecular mechanisms remain poorly understood, and effective preventive strategies against PM2.5-induced pulmonary toxicity are yet to be established‌. This study investigated the role of reactive oxygen species (ROS)-mediated pseudo-hypoxia signaling and NF-κB pathway activation in PM2.5-triggered epithelial-mesenchymal transition (EMT) and fibrosis, alongside the therapeutic potential of the antioxidant compound stilbene glucoside (TSG). ‌In vivo‌, C57BL/6 mice exposed to PM2.5 for two months developed pulmonary fibrosis, with transcriptomic analysis revealing significant alterations in pathways associated with carbohydrate metabolism, cancer signaling, and immune-related diseases‌. Concurrently, upregulated expression of EMT markers (fibronectin, vimentin), glycolysis-related genes (PKM, LDHA), and inflammatory cytokines (TGF-beta) was observed in lung tissues‌. ‌In vitro‌, PM2.5 induced EMT in BEAS-2B cells via ROS-driven mitochondrial membrane potential collapse, mitophagy, HIF-1α activation, and NF-κB-mediated inflammation, which collectively promoted a metabolic shift toward glycolysis‌. Notably, TSG treatment attenuated PM2.5-induced pulmonary fibrosis by suppressing ROS accumulation, pseudo-hypoxia signaling, and NF-κB pathway activation. These effects correlated with restored mitochondrial function and normalized glucose metabolism in cellular models‌. ‌We come to the conclusion that PM2.5 exacerbates pulmonary fibrosis through ROS/HIF-1α and NF-κB axis-driven EMT and metabolic reprogramming. TSG, as a multifunctional antioxidant, represents a promising prophylactic agent against PM2.5-associated pulmonary damage‌.

Hepatorenal protective effects of essential oils against chemical overexposure induced oxidative damage

Chemical overexposure is a significant concern in both environmental and occupational settings, often leading to oxidative stress and subsequent cellular damage. The review covers the oxidative stress induced by chemical overexposure to substances such as pesticides (including pyrethroid, deltamethrin, β-cyfluthrin, malathion, triflumuron, methomyl, diquat, cypermethrin, thiamethoxam, and profenofos), medications (acetaminophen), nanoparticles (including zinc oxide, iron, silver, and titanium dioxide), heavy metals (including cadmium, vanadium), and some organic chemicals (including diethylnitrosamine and benzo(a)pyrene). Focusing on preclinical evidence from animal models and cell-based studies, essential oils have been shown to significantly enhance antioxidative enzyme activities, including superoxide dismutase, catalase, and glutathione peroxidase, while also increasing levels of non-enzymatic antioxidants such as glutathione and uric acid. Additionally, essential oils contribute to the restoration of biochemical parameters, including creatinine, uric acid, and urea levels, while mitigating oxidative damage by reducing cell membrane injury, apoptosis, and histopathological alterations. Additionally, this review evaluates the protective benefits of essential oils against chemical overexposure in animal models. The underlying mechanism is involved in alleviating hepatorenal damage. This review underscores the considerable promise of essential oils as candidates for medicinal applications in functional foods or medicines, particularly in preventing oxidative stress induced by various chemical overexposure.

Protective effects of resveratrol against PM2.5-induced damage in hNSCs and its mitigation of PM2.5-induced mitochondrial dysfunction in a 3D scaffold system

BACKGROUND

Exposure to PM2.5 is associated with neurotoxicity and mitochondrial dysfunction. Resveratrol, a natural polyphenol, has demonstrated antioxidant and neuroprotective properties. Still, its efficacy in mitigating PM2.5-induced damage in human neural stem cells (hNSCs) and within a 3D scaffold system remains underexplored.

OBJECTIVE

This study investigated the protective effects of resveratrol against PM2.5-induced damage in hNSCs and within a 3D scaffold system.

METHODS

Assess cell viability using MTT and LIVE/DEAD assays and measure caspase activity by fluorescence analysis. Quantify gene and protein expression of key regulatory pathways using qPCR and Western blotting. Then, mitochondrial function was analyzed by measuring ATP production, mitochondrial mass, maximal respiratory rate, COX activity, membrane potential, TEM, and immunofluorescence staining. In addition, 3D scaffolds created by the CELLINK INKREDIBLE bioprinter were used to study the effect of resveratrol on PM2.5-induced hNSCs damage.

RESULTS

Resveratrol significantly improved cell viability and reduced caspase-3 and caspase-9 activities in PM2.5-treated hNSCs. Resveratrol treatment upregulated TrKBR, PI3K, AKT, CREB, PPARα, PPARγ, SIRT1 and AMPK expression. It restored mitochondrial function by increasing ATP production, mitochondrial mass, maximal respiratory rate, COX activity, and membrane potential. Using a 3D scaffold demonstrated resveratrol's potential to maintain mitochondrial function and cellular health under PM2.5 exposure.

CONCLUSION

Resveratrol can effectively reduce neurotoxicity and mitochondrial dysfunction caused by PM2.5 in hNSCs. Its protective effects against PM2.5-induced toxicity in hNSCs within a 3D bioprinted model highlight this study's translational potential. These findings emphasize its potential as a therapeutic agent against environmental neurotoxins and the development of neuroprotective strategies.

Selenium triggers AMPK-mTOR pathway to modulate autophagy related to oxidative stress of sheep Leydig cells

The objective of this study was to investigate the effect of oxidative stress induced by excessive Se on autophagy of sheep Leydig cells and its underlying mechanism. Leydig cells isolated from the testis of 8-month-old sheep were purified using a discontinuous Percoll density gradient. Cells were divided into four treatment groups (0, 2.0, 4.0 and 8.0 μmol/L of Se). After treatment with Se for 48 h, cell proliferation was detected by CCK-8 assay kit. The biochemical methods were used to evaluate the antioxidant status of Leydig cells. The mRNA transcript and protein abundance related to the AMPK-mTOR pathway and autophagy were detected by real-time PCR and western blot analysis. The results showed that the Leydig cells treated with 8.0 μmol/L Se have the lowest cell viability. The greater ROS content and lower GSH-Px activity were also observed in the Se8.0 group. The inclusion of 2.0 μmol/L Se in the medium did not affect the autophagy of Leydig cells. However, the relative abundance of ATG5 protein and LC3II/I ratio were elevated in the Se8.0 group. Oxidative stress induced by excessive Se (8.0 μmol/L) dramatically improved the abundance of key proteins related to AMPK-mTOR pathway and led to an increase of phosphorylated AMPK, mTOR and ULK1. Compared with the Se8.0 group, compound C could significantly inhibit the key molecules of AMPK-mTOR signaling pathway and mitigate the autophagy of Leydig cells induced by excessive Se. These results indicate that appropriate Se (2.0 μmol/L) can enhance the viability of sheep Leydig cells. Oxidative stress caused by Se excess can induce cell autophagy via activating AMPK-mTOR signaling pathway. The existed crosstalk between autophagy and apoptosis could decide the fate of Leydig cells. This process could play a decisive role in the maintenance of normal male fertility and spermatogenesis by affecting the number of Leydig cells in testis.

[Epidemiological characteristics of respiratory syncytial virus infection in children in Nanchang and its correlation with climate environmental factors]

OBJECTIVES

To explore the epidemiological characteristics of respiratory syncytial virus (RSV) infection in children in Nanchang and its correlation with climate environmental factors.

METHODS

The clinical data were collected from children with acute respiratory infection in Nanchang who were tested for RSV at Jiangxi Provincial Children's Hospital from January 2019 to December 2023, along with climate environmental data for the same period. The epidemiological characteristics of RSV and their correlation with climate environmental factors were investigated.

RESULTS

A total of 178 127 children underwent RSV testing from January 2019 to December 2023, with a positive detection rate of 8.35% (14 873/178 127). The positive detection rate in males was 8.92% (10 137/113 660), which was higher than that in females (7.35%, 4 736/64 467). The differences in RSV positive detection rates among different age groups were statistically significant (P<0.001), with the highest rate observed in the 0 to <3 months age group (14.38%, 3 328/23 142). Peaks in RSV positive detection occurred during winter and spring periods in 2019, 2020, and 2022, while in 2023, it occurred in spring and summer periods, with no seasonality noted in 2021. The RSV positive detection rate showed a positive correlation with average humidity, average atmospheric pressure, monthly PM2.5, and monthly carbon monoxide levels (P<0.05), while it showed a negative correlation with average wind speed, average temperature, and maximum 8-hour ozone levels (P<0.05).

CONCLUSIONS

In Nanchang, the RSV positive detection rate in children with acute respiratory infection is higher in males than in females. Among children of all age groups, the infants aged 0 to <3 months have the highest detection rate of RSV. RSV infection predominantly occurs in winter and spring periods. Lower temperatures, lower wind speeds, higher humidity, and elevated levels of PM2.5 and carbon monoxide may increase the risk of RSV infection in children.

TFEB/LAMP2 contributes to PM0.2-induced autophagy-lysosome dysfunction and alpha-synuclein dysregulation in astrocytes

Atmospheric particulate matter (PM) exacerbates the risk factor for Alzheimer's and Parkinson's diseases (PD) by promoting the alpha-synuclein (α-syn) pathology in the brain. However, the molecular mechanisms of astrocytes involvement in α-syn pathology underlying the process remain unclear. This study investigated PM with particle size <200 nm (PM0.2) exposure-induced α-syn pathology in ICR mice and primary astrocytes, then assessed the effects of mammalian target of rapamycin inhibitor (PP242) in vitro studies. We observed the α-syn pathology in the brains of exposed mice. Meanwhile, PM0.2-exposed mice also exhibited the activation of glial cell and the inhibition of autophagy. In vitro study, PM0.2 (3, 10 and 30 µg/mL) induced inflammatory response and the disorders of α-syn degradation in primary astrocytes, and lysosomal-associated membrane protein 2 (LAMP2)-mediated autophagy underlies α-syn pathology. The abnormal function of autophagy-lysosome was specifically manifested as the expression of microtubule-associated protein light chain 3 (LC3II), cathepsin B (CTSB) and lysosomal abundance increased first and then decreased, which might both be a compensatory mechanism to toxic α-syn accumulation induced by PM0.2. Moreover, with the transcription factor EB (TFEB) subcellular localization and the increase in LC3II, LAMP2, CTSB, and cathepsin D proteins were identified, leading to the restoration of the degradation of α-syn after the intervention of PP242. Our results identified that PM0.2 exposure could promote the α-syn pathological dysregulation in astrocytes, providing mechanistic insights into how PM0.2 increases the risk of developing PD and highlighting TFEB/LAMP2 as a promising therapeutic target for antagonizing PM0.2 toxicity.

Interplay between microglia and environmental risk factors in Alzheimer's disease

Alzheimer's disease, among the most common neurodegenerative disorders, is characterized by progressive cognitive impairment. At present, the Alzheimer's disease main risk remains genetic risks, but major environmental factors are increasingly shown to impact Alzheimer's disease development and progression. Microglia, the most important brain immune cells, play a central role in Alzheimer's disease pathogenesis and are considered environmental and lifestyle "sensors." Factors like environmental pollution and modern lifestyles (e.g., chronic stress, poor dietary habits, sleep, and circadian rhythm disorders) can cause neuroinflammatory responses that lead to cognitive impairment via microglial functioning and phenotypic regulation. However, the specific mechanisms underlying interactions among these factors and microglia in Alzheimer's disease are unclear. Herein, we: discuss the biological effects of air pollution, chronic stress, gut microbiota, sleep patterns, physical exercise, cigarette smoking, and caffeine consumption on microglia; consider how unhealthy lifestyle factors influence individual susceptibility to Alzheimer's disease; and present the neuroprotective effects of a healthy lifestyle. Toward intervening and controlling these environmental risk factors at an early Alzheimer's disease stage, understanding the role of microglia in Alzheimer's disease development, and targeting strategies to target microglia, could be essential to future Alzheimer's disease treatments.

Neurotoxicity of fine and ultrafine particulate matter: A comprehensive review using a toxicity pathway-oriented adverse outcome pathway framework

Fine particulate matter (PM2.5) can cause brain damage and diseases. Of note, ultrafine particles (UFPs) with an aerodynamic diameter less than or equal to 100 nm are a growing concern. Evidence has suggested toxic effects of PM2.5 and UFPs on the brain and links to neurological diseases. However, the underlying mechanism has not yet been fully illustrated due to the variety of the study models, different endpoints, etc. The adverse outcome pathway (AOP) framework is a pathway-based approach that could systematize mechanistic knowledge to assist health risk assessment of pollutants. Here, we constructed AOPs by collecting molecular mechanisms in PM-induced neurotoxicity assessments. We chose particulate matter (PM) as a stressor in the Comparative Toxicogenomics Database (CTD) and identified the critical toxicity pathways based on Ingenuity Pathway Analysis (IPA). We found 65 studies investigating the potential mechanisms linking PM2.5 and UFPs to neurotoxicity, which contained 2, 675 genes in all. IPA analysis showed that neuroinflammation signaling and glucocorticoid receptor signaling were the common toxicity pathways. The upstream regulator analysis (URA) of PM2.5 and UFPs demonstrated that the neuroinflammation signaling was the most initially triggered upstream event. Therefore, neuroinflammation was recognized as the MIE. Strikingly, there is a clear sequence of activation of downstream signaling pathways with UFPs, but not with PM2.5. Moreover, we found that inflammation response and homeostasis imbalance were key cellular events in PM2.5 and emphasized lipid metabolism and mitochondrial dysfunction, and blood-brain barrier (BBB) impairment in UFPs. Previous AOPs, which only focused on phenotypic changes in neurotoxicity upon PM exposure, we for the first time propose AOP framework in which PM2.5 and UFPs may activate pathway cascade reactions, resulting in adverse outcomes associated with neurotoxicity. Our toxicity pathway-based approach not only advances risk assessment for PM-induced neurotoxicity but shines a spotlight on constructing AOP frameworks for new chemicals.

The firestorm within: A narrative review of extreme heat and wildfire smoke effects on brain health

Climate change is generating increased heatwaves and wildfires across much of the world. With these escalating environmental changes comes greater impacts on human health leading to increased numbers of people suffering from heat- and wildfire smoke-associated respiratory and cardiovascular impairment. One area of health impact of climate change that has received far less attention is the effects of extreme heat and wildfire smoke exposure on human brain health. As elevated temperatures, and wildfire-associated smoke, are increasingly experienced simultaneously over summer periods, understanding this combined impact is critical to management of human health especially in the elderly, and people with dementia, and other neurological disorders. Both extreme heat and wildfire smoke air pollution (especially particulate matter, PM) induce neuroinflammatory and cerebrovascular effects, oxidative stress, and cognitive impairment, however the combined effect of these impacts are not well understood. In this narrative review, a comprehensive examination of extreme heat and wildfire smoke impact on human brain health is presented, with a focus on how these factors contribute to cognitive impairment, and dementia, one of the leading health issues today. Also discussed is the potential impact of combined heat and wildfire smoke on brain health, and where future efforts should be applied to help advance knowledge in this rapidly growing and critical field of health research.

Autophagy alleviates hippocampal neuroinflammation by inhibiting the NLRP3 inflammasome in a juvenile rat model exposed particulate matter

Ambient fine particulate matter (PM) is a global public and environmental problem. PM is closely associated with several neurological diseases, which typically involve neuroinflammation. We investigated the impact of PM exposure on neuroinflammation using both in vivo (in a juvenile rat model with PM exposure concentrations of 1, 2, and 10 mg/kg for 28 days) and in vitro (in BV-2 and HT-22 cell models with PM concentrations of 50-200 μg/ml for 24 h). We observed that PM exposure induced the activation of the NLRP3 inflammasome, leading to the production of IL-1β and IL-18 in the rat hippocampus and BV-2 cells. Furthermore, inhibition of the NLRP3 inflammasome with MCC950 effectively reduced neuroinflammation and ameliorated hippocampal damage. In addition, autophagy activation was observed in the hippocampus of PM-exposed rats, and the promotion of autophagy by rapamycin (Rapa) effectively attenuated the NLRP3-mediated neuroinflammation induced by PM exposure. However, autophagic flow was blocked in BV-2 cells exposed to PM, and Rapa failed to ameliorate NLRP3 inflammasome activation. We found that autophagy was activated in HT-22 cells exposed to PM and that treatment with Rapa reduced the release of reactive oxygen species (ROS) and malondialdehyde (MDA), as well as cell apoptosis. In a subsequent coculture model of BV-2 and HT-22 cells, we observed the activation of the NLRP3 inflammasome in BV-2 cells when the HT-22 cells were exposed to PM, and this activation was alleviated when PM-exposed HT-22 cells were pretreated with Rapa. Overall, our study revealed that PM exposure triggered hippocampal neuroinflammation by activating the NLRP3 inflammasome. Notably, autophagy mitigated NLRP3 inflammasome activation, potentially by reducing neuronal ROS and apoptosis. This research emphasized the importance of reducing PM exposure and provided valuable insight into its neurotoxicity.

Loganin attenuates neuroinflammation after ischemic stroke and fracture by regulating α7nAChR-mediated microglial polarization

Fracture in acute stage of ischemic stroke can increase inflammatory response and enhance stroke injury. Loganin alleviates the symptoms of many inflammatory diseases through its anti-inflammatory effect, but its role in ischemic stroke and fracture remains to be explored. Here, mice were handled with permanent middle cerebral artery occlusion (pMCAO) followed by tibial fracture 1 day later to establish a pMCAO+fracture model. Loganin or Methyllycaconitine (MLA, a specific a7nAchR inhibitor) were intragastrically administered 2 or 0.5 h before pMCAO, respectively. And mouse motor function and infarct volume were evaluated 3 days after pMCAO. We found that loganin alleviated the neurological deficit, cerebral infarction volume, and neuronal apoptosis (NeuN⁺ TUNEL⁺ ) in mice with pMCAO+fracture. And loganin suppressed pMCAO+fracture-induced neuroinflammation by promoting M2 microglia polarization (Iba1⁺ CD206⁺ ) and inhibiting M1 microglia polarization (Iba1⁺ CD11b⁺ ). While administration with MLA reversed the protective effect of loganin on pMCAO+fracture-induced neurological deficit and neuroinflammation. Next, LPS was used to stimulate BV2 microglia to simulate pMCAO+fracture-induced inflammatory microenvironment in vitro. Loganin facilitated the transformation of LPS-stimulated BV2 cells from M1 pro-inflammatory state (CD11b⁺ ) to M2 anti-inflammatory state (CD206⁺ ), which was antagonized by treatment with MLA. And loganin induced autophagy activation in LPS-stimulated BV2 cells by activating a7nAchR. Moreover, treatment with rapamycin (an autophagy activator) neutralized the inhibitory effect of MLA on loganin induced transformation of BV2 cells to M2 phenotype. Furthermore, BV2 cells were treated with LPS, LPS + loganin, LPS + loganin+MLA, or LPS + loganin+MLA+ rapamycin to obtain conditioned medium (CM) for stimulating primary neurons. Loganin reduced the damage of primary neurons caused by LPS-stimulated BV2 microglia through activating a7nAchR and inducing autophagy activation. In conclusion, loganin played anti-inflammatory and neuroprotective roles in pMCAO + fracture mice by activating a7nAchR, enhancing autophagy and promoting M2 polarization of microglia.

A review of respirable fine particulate matter (PM2.5)-induced brain damage

Respirable fine particulate matter (PM_2.5) has been one of the most widely publicized indicators of pollution in recent years. Epidemiological studies have established a strong association between PM_2.5, lung disease, and cardiovascular disease. Recent studies have shown that PM_2.5 is also strongly associated with brain damage, mainly cerebrovascular damage (stroke) and neurological damage to the brain (changes in cognitive function, dementia, psychiatric disorders, etc.). PM_2.5 can pass through the lung–gas–blood barrier and the “gut–microbial–brain” axis to cause systemic oxidative stress and inflammation, or directly enter brain tissue via the olfactory nerve, eventually damaging the cerebral blood vessels and brain nerves. It is worth mentioning that there is a time window for PM_2.5-induced brain damage to repair itself. However, the exact pathophysiological mechanisms of brain injury and brain repair are not yet fully understood. This article collects and discusses the mechanisms of PM_2.5-induced brain injury and self-repair after injury, which may provide new ideas for the prevention and treatment of cerebrovascular and cerebral neurological diseases.

Dioscin promotes autophagy by regulating the AMPK-mTOR pathway in ulcerative colitis

BACKGROUND

Dioscin is reported to alleviate the dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) in mice. Autophagy plays an anti-inflammatory role in UC. We herein aimed to explore the biological functions of dioscin in autophagy in UC.

METHODS

To explore the effects of dioscin on UC progression, a DSS-induced mouse model of UC was established. Body weight, disease activity index and macroscopic damage index scores were recorded for seven days. Hematoxylin & Eosin (HE) staining was used to stain colon sections and an BX53 microscope was prepared to observe pathological changes. The activities of glutathione, superoxidative dismutase, and malondialdehyde were determined by commercially available kits. Western blotting was performed to measure the protein levels of p-AMPK/AMPK, p-mTOR/mTOR and autophagy-related genes.

RESULTS

The DSS-induced colitis and oxidative stress in mice were ameliorated after dioscin treatment. Dioscin promoted the phosphorylation of AMPK to inhibit mTOR activation and facilitated autophagy in DSS-induced mice model of UC.

CONCLUSION

Dioscin promotes autophagy by promoting the phosphorylation of AMPK to inhibit mTOR activation in ulcerative colitis.