Exposure to ambient fine particles causes abnormal energy metabolism and ATP decrease in lung tissues

Phosphocholine-induced energy source shift alleviates mitochondrial dysfunction in lung cells caused by geospecific PM2.5 components

Fine particulate matter (PM2.5) is globally recognized for its adverse implications on human health. Yet, remain limited the individual contribution of particular PM2.5 components to its toxicity, especially considering regional disparities. Moreover, prevention solutions for PM2.5-associated health effects are scarce. In the present study, we comprehensively characterized and compared the primary PM2.5 constituents and their altered metabolites from two locations: Taiyuan and Guangzhou. Analysis of year-long PM2.5 samples revealed 84 major components, encompassing organic carbon, elemental carbon, ions, metals, and organic chemicals. PM2.5 from Taiyuan exhibited higher contamination, associated health risks, dithiothreitol activity, and cytotoxicities than Guangzhou's counterpart. Applying metabolomics, BEAS-2B lung cells exposed to PM2.5 from both cities were screened for significant alterations. A correlation analysis revealed the metabolites altered by PM2.5 and the critical toxic PM2.5 components in both regions. Among the PM2.5-down-regulated metabolites, phosphocholine emerged as a promising intervention for PM2.5 cytotoxicities. Its supplementation effectively attenuated PM2.5-induced energy metabolism disorder and cell death via activating fatty acid oxidation and inhibiting Phospho1 expression. The highlighted toxic chemicals displayed combined toxicities, potentially counteracted by phosphocholine. Our study offered a promising functional metabolite to alleviate PM2.5-induced cellular disorder and provided insights into the geo-based variability in toxic PM2.5 components.

Adverse effects of exposure to fine particles and ultrafine particles in the environment on different organs of organisms

Particulate pollution is a global risk factor that seriously threatens human health. Fine particles (FPs) and ultrafine particles (UFPs) have small particle diameters and large specific surface areas, which can easily adsorb metals, microorganisms and other pollutants. FPs and UFPs can enter the human body in multiple ways and can be easily and quickly absorbed by the cells, tissues and organs. In the body, the particles can induce oxidative stress, inflammatory response and apoptosis, furthermore causing great adverse effects. Epidemiological studies mainly take the population as the research object to study the distribution of diseases and health conditions in a specific population and to focus on the identification of influencing factors. However, the mechanism by which a substance harms the health of organisms is mainly demonstrated through toxicological studies. Combining epidemiological studies with toxicological studies will provide a more systematic and comprehensive understanding of the impact of PM on the health of organisms. In this review, the sources, compositions, and morphologies of FPs and UFPs are briefly introduced in the first part. The effects and action mechanisms of exposure to FPs and UFPs on the heart, lungs, brain, liver, spleen, kidneys, pancreas, gastrointestinal tract, joints and reproductive system are systematically summarized. In addition, challenges are further pointed out at the end of the paper. This work provides useful theoretical guidance and a strong experimental foundation for investigating and preventing the adverse effects of FPs and UFPs on human health.

Unravelling the signaling power of pollutants

Exposure to environmental pollutants contributes to diverse pathologies, including pulmonary disease, lower respiratory infections, cancer, and stroke. Pollutants' entry can occur through inhalation, traversing endothelial and epithelial barriers, and crossing the blood-brain barrier, leading to a wide distribution throughout the human body via systemic circulation. Pollutants cause cellular damage by multiple mechanisms encompassing oxidative stress, mitochondrial dysfunction, (neuro)inflammation, and protein instability/proteotoxicity. Sensing pollutants has added a new dimension to disease progression and drug failure. Understanding the molecular pathways and potential receptor binding/signaling that underpin 'sensing' could contribute to ways to combat the detrimental effects of pollutants. We highlight key points of pollutant signaling, crosstalk with receptors acting as drug targets for chronic diseases, and discuss the potential for future therapeutics.

The mediating role of exhaled breath condensate metabolites in the effect of particulate matter on pulmonary function in schoolchildren: A crossover intervention study

The role played by metabolites in exhaled breath condensate (EBC) in the effect of PM on schoolchildren's pulmonary function has received little attention. Accordingly, we examined whether metabolites in EBC mediated the effect of PM10, PM2.5, and PM1 on the pulmonary function of schoolchildren at a residential primary school who had received an air-cleaner cross-over intervention. Samples of EBC were collected from a total of 60 schoolchildren and subjected to metabolomics analysis. We found that the effect of PM on six pulmonary function indicators was mediated by the following nine lipid peroxidation-related and energy metabolism-related metabolites present in EBC: 4-hydroxynonenal, arachidoyl ethanolamide, dl-pyroglutamic acid, 5-deoxy-d-glucose, myristic acid, lauric acid, linoleic acid, l-proline, and palmitic acid. However, while all nine of these metabolites mediated the effects of PM on boys' pulmonary function, only 4-hydroxynonenal, arachidoyl ethanolamide, and dl-pyroglutamic acid mediated the effects of PM on girls' pulmonary function. Overall, our results show that (1) short-term exposure to PM affected the schoolchildren's pulmonary function by causing an imbalance between lipid peroxidation and glutathione-based antioxidant activity and by perturbing energy metabolism in respiratory system and (2) there was a sex-dependent antioxidant response to PM exposure, with boys being less resistant than girls.

Blockage of ATPase-mediated energy supply inducing metabolic disturbances in algal cells under silver nanoparticles stress

Adenosine triphosphate (ATP) generation of aquatic organisms is often subject to nanoparticles (NPs) stress, involving extensive reprogramming of gene expression and changes in enzyme activity accompanied by metabolic disturbances. However, little is known about the mechanism of energy supply by ATP to regulate the metabolism of aquatic organisms under NPs stress. Here, we selected extensively existing silver nanoparticles (AgNPs) to investigate their implications on ATP generation and relevant metabolic pathways in alga (Chlorella vulgaris). Results showed that ATP content significantly decreased by 94.2% of the control (without AgNPs) in the algal cells at 0.20 mg/L AgNPs, which was mainly attributed to the reduction of chloroplast ATPase activity (81.4%) and the downregulation of ATPase-coding genes atpB and atpH (74.5%-82.8%) in chloroplast. Molecular dynamics simulations demonstrated that AgNPs competed with the binding sites of substrates adenosine diphosphate and inorganic phosphate by forming a stable complex with ATPase subunit beta, potentially resulting in the reduced binding efficiency of substrates. Furthermore, metabolomics analysis proved that the ATP content positively correlated with the content of most differential metabolites such as D-talose, myo-inositol, and L-allothreonine. AgNPs remarkably inhibited ATP-involving metabolic pathways, including inositol phosphate metabolism, phosphatidylinositol signaling system, glycerophospholipid metabolism, aminoacyl-tRNA biosynthesis, and glutathione metabolism. These results could provide a deep understanding of energy supply in regulating metabolic disturbances under NPs stress.

Dietary intake of household cadmium-contaminated rice caused genome-wide DNA methylation changes on gene/hubs related to metabolic disorders and cancers

Cadmium (Cd) contamination in food has raised broad concerns in food safety and human health. The toxicity of Cd to animals/humans have been widely reported, yet little is known about the health risk of dietary Cd intake at the epigenetic level. Here, we investigated the effect of a household Cd-contaminated rice (Cd-rice) on genome-wide DNA methylation (DNAm) changes in the model mouse. Feeding Cd-rice increased kidney Cd and urinary Cd concentrations compared with the Control rice (low-Cd rice), whereas supplementation of ethylenediamine tetraacetic acid iron sodium salt (NaFeEDTA) in the diet significantly increased urinary Cd and consequently decreased kidney Cd concentrations. Genome-wide DNAm sequencing revealed that dietary Cd-rice exposure caused the differentially methylated sites (DMSs), which were mainly located in the promoter (32.5%), downstream (32.5%), and intron (26.1%) regions of genes. Notably, Cd-rice exposure induced hypermethylation at the promoter sites of genes Caspase-8 and interleukin-1β (Il-1β), and consequently, their expressions were down-regulated. The two genes are critical in apoptosis and inflammation, respectively. In contrast, Cd-rice induced hypomethylation of the gene midline 1 (Mid1), which is vital to neurodevelopment. Furthermore, 'pathways in cancer' was significantly enriched as the leading canonical pathway. Supplementation of NaFeEDTA partly alleviated the toxic symptoms and DNAm alternations induced by Cd-rice exposure. These results highlight the broad effects of elevated dietary Cd intake on the level of DNAm, providing epigenetic evidence on the specific endpoints of health risks induced by Cd-rice exposure.

Respiratory Effects of Traffic-Related Air Pollution: A Randomized, Crossover Analysis of Lung Function, Airway Metabolome, and Biomarkers of Airway Injury

BACKGROUND

Exposure to traffic-related air pollution (TRAP) has been associated with increased risks of respiratory diseases, but the biological mechanisms are not yet fully elucidated.

OBJECTIVES

Our aim was to evaluate the respiratory responses and explore potential biological mechanisms of TRAP exposure in a randomized crossover trial.

METHODS

We conducted a randomized crossover trial in 56 healthy adults. Each participant was exposed to high- and low-TRAP exposure sessions by walking in a park and down a road with high traffic volume for 4 h in random order. Respiratory symptoms and lung function, including forced expiratory volume in the first second (FEV 1 ), forced vital capacity (FVC), the ratio of FEV 1 to FVC, and maximal mid-expiratory flow (MMEF), were measured before and after each exposure session. Markers of 8-isoprostane, tumor necrosis factor- α (TNF- α ), and ezrin in exhaled breath condensate (EBC), and surfactant proteins D (SP-D) in serum were also measured. We used linear mixed-effects models to estimate the associations, adjusted for age, sex, body mass index, meteorological condition, and batch (only for biomarkers). Liquid chromatography-mass spectrometry was used to profile the EBC metabolome. Untargeted metabolome-wide association study (MWAS) analysis and pathway enrichment analysis using mummichog were performed to identify critical metabolomic features and pathways associated with TRAP exposure.

RESULTS

Participants had two to three times higher exposure to traffic-related air pollutants except for fine particulate matter while walking along the road compared with in the park. Compared with the low-TRAP exposure at the park, high-TRAP exposure at the road was associated with a higher score of respiratory symptoms [2.615 (95% CI: 0.605, 4.626), p = 1.2 × 10 - 2 ] and relatively lower lung function indicators [- 0.075 L (95% CI: - 0.138 , - 0.012 ), p = 2.1 × 10 - 2 ] for FEV 1 and - 0.190 L / s (95% CI: - 0.351 , - 0.029 ; p = 2.4 × 10 - 2 ) for MMEF]. Exposure to TRAP was significantly associated with changes in some, but not all, biomarkers, particularly with a 0.494 -ng / mL (95% CI: 0.297, 0.691; p = 9.5 × 10 - 6 ) increase for serum SP-D and a 0.123 -ng / mL (95% CI: - 0.208 , - 0.037 ; p = 7.2 × 10 - 3 ) decrease for EBC ezrin. Untargeted MWAS analysis revealed that elevated TRAP exposure was significantly associated with perturbations in 23 and 32 metabolic pathways under positive- and negative-ion modes, respectively. These pathways were most related to inflammatory response, oxidative stress, and energy use metabolism.

CONCLUSIONS

This study suggests that TRAP exposure might lead to lung function impairment and respiratory symptoms. Possible underlying mechanisms include lung epithelial injury, inflammation, oxidative stress, and energy metabolism disorders. https://doi.org/10.1289/EHP11139.

Ultrafine Particles Issued from Gasoline-Fuels and Biofuel Surrogates Combustion: A Comparative Study of the Physicochemical and In Vitro Toxicological Effects

Gasoline emissions contain high levels of pollutants, including particulate matter (PM), which are associated with several health outcomes. Moreover, due to the depletion of fossil fuels, biofuels represent an attractive alternative, particularly second-generation biofuels (B2G) derived from lignocellulosic biomass. Unfortunately, compared to the abundant literature on diesel and gasoline emissions, relatively few studies are devoted to alternative fuels and their health effects. This study aimed to compare the adverse effects of gasoline and B2G emissions on human bronchial epithelial cells. We characterized the emissions generated by propane combustion (CAST1), gasoline Surrogate, and B2G consisting of Surrogate blended with anisole (10%) (S+10A) or ethanol (10%) (S+10E). To study the cellular effects, BEAS-2B cells were cultured at air-liquid interface for seven days and exposed to different emissions. Cell viability, oxidative stress, inflammation, and xenobiotic metabolism were measured. mRNA expression analysis was significantly modified by the Surrogate S+10A and S+10E emissions, especially CYP1A1 and CYP1B1. Inflammation markers, IL-6 and IL-8, were mainly downregulated doubtless due to the PAHs content on PM. Overall, these results demonstrated that ultrafine particles generated from biofuels Surrogates had a toxic effect at least similar to that observed with a gasoline substitute (Surrogate), involving probably different toxicity pathways.

Long-term personal PM2.5 exposure and lung function alternation: A longitudinal study in Wuhan urban adults

BACKGROUND

The effect of long-term PM_2.5 exposure on lung function has not been well established.

OBJECTIVES

To investigate the effects of long-term personal PM_2.5 exposure on lung function decline, obstructive, and restrictive ventilatory disorders.

METHOD

Personal PM_2.5 concentrations were evaluated using an estimation model. Lung function parameters including forced vital capacity (FVC), forced expiratory volume in 1 s (FEV₁) and peak expiratory flow (PEF) were measured in 3053 Wuhan participants from the Wuhan-Zhuhai cohort and were repeated every 3 years. Participants were classified into persistently high exposure group, persistently low exposure group and inconsistent exposure group according to the median of PM_2.5 concentration of each visit. Mixed linear models with subject-specific random intercept were used to assess the association of 3-year change of lung function with personal PM_2.5 exposure, and generalized linear models were used to assess the association of 6-year change of lung function with personal PM_2.5 exposure. Cox regression models were applied to assess the associations of PM_2.5 with obstructive and restrictive ventilatory disorders.

RESULTS

The medians of personal PM_2.5 concentrations at baseline and two follow-ups were 153.18, 209.57 and 83.78 μg/m³, respectively. Compared with participants in the persistently low exposure group, participants in the persistently high exposure group showed a 2.99 % (95 % CI: 0.91, 5.08), a 380.15 mL/s (95 % CI: 32.82, 727.48) and a 5.98 % (95 % CI: 0.84, 11.11) additional decline in FEV₁/FVC, PEF and PEFpred after 6 years, respectively. Stratified analyses showed that age, gender, body mass index, smoking status and drinking status had no significant modification effect on the associations. The associations of PM_2.5 exposure with obstructive and restrictive ventilatory disorders were not significant, except for a positive association between persistently high PM_2.5 exposure and restrictive ventilatory disorder among ever drinkers.

CONCLUSION

Long-term high PM_2.5 exposure was associated with FEV₁/FVC, PEF and PEFpred declines.

Energy metabolism disorders and oxidative stress in the SH-SY5Y cells following PM2.5 air pollution exposure

Studies have shown that PM_2.5 exposure can induce neuronal apoptosis and neurobehavioral changes in animal experiments due partly to the mitochondria-mediated oxidative damage. How does it affect the mitochondrial energy metabolism as well as the neuronal damage, however, remain unclear. This study aimed to investigate the molecular processes of energy metabolism and oxidative damage induced by ambient PM_2.5 exposure in SH-SY5Y cells. SH-SY5Y cells were treated with PM_2.5 to establish a cytotoxicity model. A Seahorse Extracellular Flux Analyzer (XFp) was performed to evaluate the cellular mitochondrial respiratory and glycolysis after exposure to PM_2.5. The dose- and time-dependent effects of PM_2.5 on oxidative damage and apoptosis were analyzed. To further explore the relationship among oxidative damage, energy metabolism and apoptosis, SH-SY5Y cells were co-cultured with BHA and PM_2.5 for 24 h. The results demonstrated that the basic respiration and ATP production, the typical index of mitochondrial respiration as well as glycolysis, significantly reduced in SH-SY5Y cells with dose and time dependent. At the same time, the PM_2.5 could significantly decrease the cell viability and Mn-SOD activity, and increase the ROS levels and apoptosis rate as the escalation of dose and the extension of time. Importantly, the application of BHA could synchronously recover the PM_2.5 induced cell energy metabolism disorder, oxidative damage, and apoptosis. It seems that the abnormal cellular energy metabolism may be caused by oxidative damage following fine particles exposure, and further led to apoptosis.

Metformin mitigates gas explosion‑induced blast lung injuries through AMPK‑mediated energy metabolism and NOX2‑related oxidation pathway in rats

Gas explosions are a recurrent event in coal mining that cause severe pulmonary damage due to shock waves, and there is currently no effective targeted treatment. To illustrate the mechanism of gas explosion-induced lung injury and to explore strategies for blast lung injury (BLI) treatment, the present study used a BLI rat model and supplementation with metformin (MET), an AMP-activated protein kinase (AMPK) activator, at a dose of 10 mg/kg body weight by intraperitoneal injection. Protein expression levels were detected by western blotting. Significantly decreased expression of phosphorylated (p)-AMPK, peroxisome proliferator-activated receptor-γ coactivator-1α (PGC1α) and metabolic activity were observed in the BLI group compared with those in the control group. However, the mitochondrial stability, metabolic activity and expression of p-AMPK and PGC1α were elevated following MET treatment. These results suggested that MET could attenuate gas explosion-induced BLI by improving mitochondrial homeostasis. Meanwhile, high expression of nicotinamide adenine dinucleotide phosphate oxidase (NOX2) and low expression of catalase (CAT) were observed in the BLI group. The expression levels of NOX2 and CAT were restored in the BLI + MET group relative to changes in the BLI group, and the accumulation of oxidative stress was successfully reversed following MET treatment. Overall, these findings revealed that MET could alleviate BLI by activating the AMPK/PGC1α pathway and inhibiting oxidative stress caused by NOX2 activation.

Oxygen sensors mediated HIF-1α accumulation and translocation: A pivotal mechanism of fine particles-exacerbated myocardial hypoxia injury

Epidemiological studies have demonstrated a strong association of ambient fine particulate matter (PM_2.5) exposure with the increasing mortality by ischemic heart disease (IHD), but the involved mechanisms remain poorly understood. Herein, we found that the chronic exposure of real ambient PM_2.5 led to the upregulation of hypoxia-inducible factor-1 alpha (HIF-1α) protein in the myocardium of mice, accompanied by obvious myocardial injury and hypertrophy. Further data from the hypoxia-ischemia cellular model indicated that PM_2.5-induced HIF-1α accumulation was responsible for the promotion of myocardial hypoxia injury. Moreover, the declined ATP level due to the HIF-1α-mediated energy metabolism remodeling from β-oxidation to glycolysis had a critical role in the PM_2.5-increased myocardial hypoxia injury. The in-depth analysis delineated that PM_2.5 exposure decreased the binding of prolyl hydroxylase domain 2 (PHD2) and HIF-1α and subsequent ubiquitin protease levels, thereby leading to the accumulation of HIF-1α. Meanwhile, factor-inhibiting HIF1 (FIH1) expression was down-regulated by PM_2.5, resulting in the enhanced translocation of HIF-1α to the nucleus. Overall, our study provides valuable insight into the regulatory role of oxygen sensor-mediated HIF-1α stabilization and translocation in PM-exacerbated myocardial hypoxia injury, we suggest this adds significantly to understanding the mechanisms of haze particles-caused burden of cardiovascular disease.

PM2.5 exposure inducing ATP alteration links with NLRP3 inflammasome activation

Fine particulate matter (PM_2.5) has been the primary air pollutant and the fourth leading risk factor for disease and death in the world. Exposure to PM_2.5 is related to activation of the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome, but the mechanism of PM_2.5 affecting the NLRP3 inflammasome is still unclear. Previous studies have shown that PM_2.5 can cause alterations in adenosine triphosphate (ATP), and an increase in extracellular ATP and a decrease in intracellular ATP can trigger the activation process of the NLRP3 inflammasome. Therefore, we emphasize that ATP changes may be the central link and key mechanism of PM_2.5 exposure that activates the NLRP3 inflammasome. This review briefly elucidates and summarizes how PM_2.5 acts on ATP and subsequently further impacts the NLRP3 inflammasome. Investigation of ATP changes due to exposure to PM_2.5 may be essential to regulate NLRP3 inflammasome activation and treat inflammation-related diseases such as coronavirus disease 2019 (COVID-19).

PM2.5 induces intestinal damage by affecting gut microbiota and metabolites of rats fed a high-carbohydrate diet

PM_2.5 has a major impact on the gastrointestinal system, but the specific mechanism behind this action is not fully understood. Current studies have focused on the relationship between PM_2.5 and intestinal flora disorder, while ignoring the important influence of diet on gut microbes. In this study, SD rats were fed either a normal, high-fat, or high-carbohydrate diet for two months and exposed to PM_2.5 (7 mg/kg b.w.) by intratracheal instillation. The results showed that the body and kidney weights of the rats in the high-fat diet group were significantly increased relative to those with a normal diet, and changes in the intestinal microbes and metabolites induced by PM_2.5 were observed. Rats in the high-carbohydrate diet group had a significant response, and the diversity and richness indices of the flora were reduced (p < 0.05); additionally, intestinal Biffidobacterium and Lactobacillus were enriched, while many endogenous metabolites were found. Some amino acids derivatives and long-chain fatty acids were increased (p < 0.05). Both diet structure and PM_2.5 exposure can affect the composition of gut microbiota, and intestinal metabolites may be associated with cell membrane damage when a high-carbohydrate diet interacts with PM_2.5. This study considers multiple dietary factors to further supplement the evidence of intestinal damage via PM_2.5.

TBBPA stimulated cell migration of endometrial cancer via the contribution of NOX-generated ROS in lieu of energy metabolism

Due to the extensive applications and deleterious effects of Tetrabromobisphenol A (TBBPA), the health risk and possible mechanisms have been a topic of concern. However, the knowledge on carcinogenic risk of TBBPA and corresponding mechanisms remains scarce. In this study, endometrial cancer cells were exposed to low doses of TBBPA and its main derivatives including TBBPA bis (2,3-dibromopropyl ether) (TBBPA-BDBPE) and TBBPA bis (2-hydroxyethyl ether) (TBBPA-BHEE). The data from wound healing and transwell assays demonstrated that TBBPA treatment exhibited the strongest enhanced effect on cell migration among other tested treatments. Of note, the process of invasion rather than epithelial-mesenchymal transition (EMT) was accompanied by the occurrence of migration elevated by TBBPA. Furthermore, the levels of several metabolite indicators were measured to assess the underlying mechanisms involved in TBBPA-induced cell migration. The findings suggested that NADPH oxidase (NOX)-driven ROS instead of energy metabolism was sensitive to TBBPA stimulation. In addition, molecular docking supported a link between TBBPA ligand and NOX receptor. Accordingly, this study has provided new insights for TBBPA-induced carcinogenic effects and may arise peoples' vigilance to environmental pollution of brominated flame retardant.

Exposure to fine particulate matter induces self-recovery and susceptibility of oxidative stress and inflammation in rat lungs

PM_2.5 induces pulmonary inflammation via oxidative stress, and this role in the lungs is widely accepted, but studies on whether oxidative stress and inflammation can self-recover and be fully restored are limited. In this study, the oxidative stress and inflammation in the lungs of rats, which were first exposed to different PM_2.5 dosages (0, 0.5, 3.0, and 15.0 mg/kg body weight) and different recovery days (0, 15, and 30 days) and then were exposed to the same PM_2.5 dosages (30 mg/kg b.w.) after 30 days of recovery, were investigated. Results showed that the activity of superoxide dismutase (SOD) was significantly inhibited, and the levels of malondialdehyde (MDA), inducible nitric oxide synthase (iNOS), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-1β (IL-1β) significantly increased. These changes were accompanied with damage to the pathological structure of the rat lungs. After stopping PM_2.5 exposure, the difference between the PM_2.5 group and the control group gradually decreased with the extension of recovery time. However, when the rats were again exposed to the same dose of PM_2.5, the levels of IL-6, IL-1β, TNF-α, MDA, and iNOS were significantly increased, and the activities of SOD and GSH-Px were significantly inhibited in the high-dose group. And the high-dose group was accompanied by more severe lung pathological structural damage. Results showed that PM_2.5 could induce oxidative stress and inflammatory damage in the lungs of rats, and these damages gradually recovered as exposure ceased, but increased lung susceptibility in rats.

Paclitaxel inhibits the migration of CD133+ U251 malignant glioma cells by reducing the expression of glycolytic enzymes

Energy metabolic reprogramming (EMR) allows for the rearrangement of a series of metabolic genes and proteins when tumor cells adapt to their microenvironment. EMR is characterized by changes in the metabolic pattern and metabolic intermediates to meet the needs of tumor cells for their malignant proliferation and infiltrative growth. The present study investigated the role of low-dose paclitaxel (PTX) in changing the expression levels of key genes and proteins during glycolysis in CD133+ U251 glioma cells and explored the relevant regulatory mechanisms of action at the molecular level. CD133 immunomagnetic beads were applied to malignant CD133+ U251 glioma cells, which were then divided into a negative control and an experimental group treated with 1, 2, 4 or 8 µM PTX for 72 h. Cell Counting Kit-8 (CCK-8) was used to measure U251 cell proliferation. RNA and protein were extracted from the malignant glioma cells in all groups to observe changes in the expression levels of key glycolytic enzymes, such as glucose transporter 1 (GLUT1), pyruvate kinase M (PKM) and lactate dehydrogenase A (LDHA), using reverse transcription-quantitative PCR and western blot assays. Transwell migration assays were performed to quantify the effects of PTX solution on U251 cells. CD133+ U251 glioma cells were isolated successfully. CD1133+ cells had a higher rate of proliferation compared with CD1133- cells. In CD1133+ cells treated with PTX, a dose-dependent reduction in the expression levels of the key glycolytic enzymes GLUT1, PKM and LDHA was observed at both the mRNA and protein levels. PTX solution also inhibited cell migration. Differences between the control and experimental groups were statistically significant (P<0.05). Since glycolysis plays an indispensable role in the proliferation and migration of stem cell-like glioma cells, PTX may inhibit tumor cell growth by downregulating the gene and protein expression levels of glycolytic enzymes in CD133+ glioma cells.

Urban particulate matter disturbs the equilibrium of mitochondrial dynamics and biogenesis in human vascular endothelial cells

Since ambient particulate matter (APM) is closely related to cardiovascular damage with mitochondria being its potential targets, this study was designed to explore the impact of APM on mitochondrial homeostasis, especially on mitochondrial dynamics and biogenesis in human vascular endothelial cells, using a kind of standard material, PM SRM1648a. As a result, internalized particles lead to mitochondrial dysfunction in EA.hy926 human endothelial cells, including mitochondrial reactive oxygen species (mtROS) overproduction, mitochondrial membrane potential (MMP) reduction and adenosine triphosphate (ATP) inhibition, coupled with additional release of mitochondrial DNA (mtDNA) into the cytosol. Moreover, morphological and structural changes in mitochondria are observed in response to PM SRM1648a. In that aspect, according to the evidence of shorter fragmented mitochondria dispersed throughout the cytoplasm, along with aberrant upregulation of fission-related mRNAs/proteins, the mitochondria exhibit a fission phenotype shifting from intact reticular network to fragmentized punctate shapes. Mechanistically, PM SRM1648a facilitates phosphorylation of DRP1 at Ser616 in HUVECs, and triggers its dephosphorylation at Ser637 residue in both EA.hy926 and HUVECs, which are supportive events for mitochondrial fission during particle exposure. Additionally, suppression of a master energy modulator, PGC-1α, reveals that PM SRM1648a has the ability to impair mitochondrial biogenesis. Collectively, it could be well concluded that PM SRM1648a interferes with the equilibrium of mitochondrial dynamics and biogenesis, which is likely to play a pivotal role in mitochondrial dysfunction driven by particles, eventually contributing to endothelial cell damage. Of note, it is more reasonable to conduct risk assessment from both cellular level and subcellular structures, among which mitochondria-targeted toxicity supplements more comprehensive understanding of APM inducible vascular toxicity.

Critical biomarkers for myocardial damage by fine particulate matter: Focused on PPARα-regulated energy metabolism

Fine particulate matter is one of the leading threats to cardiovascular health worldwide. The exploration of novel and sensitive biomarkers to detect damaging effect of fine particulate matter on cardiac tissues is of great importance in the better understanding of haze-caused myocardial injury. A link between heart failure and PPARα-regulated energy metabolism has been confirmed previously. Herein, the study intends to reveal the critical biomarkers of fine particulate matter induced myocardial damage from the PPARα-regulated energy metabolism. Ambient fine particulate matter induced severe pathological alterations in cultured cells, accompanied by the decrease in ATP content. Additionally, the expressions of CPT1/CPT2 and levels of CS and MDH, crucial members in β-oxidation and the TCA cycle, were significantly decreased. In direct contrast, fine particulate matter increased the biomarkers of glycolysis, as measured by the accumulation of pyruvate and lactate contents, and the enhanced activities of HK and PKM1/2. Importantly, fine particulate matter-exposed cardiomyocytes exhibited the reduced PPARα level, that increased when cardiomyocytes were co-incubation with WY-14643 and fine particulate matter. Simultaneously, the adverse impact of fine particulate matter on critical biomarkers were observed in β-oxidation, TCA cycle and glycolysis, associated with WY-14643 additional complement. Fine particulate matter caused the myocardial energy metabolism transformation through the regulation of PPARα expression and translation, which provided novel and critical biomarkers for haze particles-caused myocardial damage.

Molecular mechanisms linking environmental toxicants to cancer development: Significance for protective interventions with polyphenols

Human exposure to environmental toxicants with diverse mechanisms of action is a growing concern. In addition to well-recognized carcinogens, various chemicals in environmental and occupational settings have been suggested to impact health, increasing susceptibility to cancer by inducing genetic and epigenetic changes. Accordingly, in this review, we have discussed recent insights into the pathological mechanisms of these chemicals, namely their effects on cell redox and calcium homeostasis, mitochondria and inflammatory signaling, with a focus on the possible implications for multi-stage carcinogenesis and its reversal by polyphenols. Plant-derived polyphenols, such as epigallocatechin-gallate, resveratrol, curcumin and anthocyanins reduce the incidence of cancer and can be useful nutraceuticals for alleviating the detrimental outcomes of harmful pollutants. However, development of therapies based on polyphenol administration requires further studies to validate the biological efficacy, identifying effective doses, mode of action and new delivery forms. Innovative microphysiological testing models are presented and specific proposals for future trials are given. Merging the current knowledge of multifactorial actions of specific polyphenols and chief environmental toxicants, this work aims to potentiate the delivery of phytochemical-based protective treatments to individuals at high-risk due to environmental exposure.