Genome-Wide Profiling of Exosomal Long Noncoding RNAs Following Air Pollution Exposure: A Randomized, Crossover Trial.

Changes in human genome-wide long noncoding RNAs (lncRNAs) associated with air pollution are unknown. This study aimed to investigate the effect of air pollution on human exosomal lncRNAs. A randomized, crossover trial was conducted among 35 healthy adults. Participants were allocated to 4 h exposure in road (high air pollution) and park (low air pollution) sessions in random order with a 2 week washout period. RNA sequencing was performed to measure lncRNAs. Differential lncRNAs were identified using a linear mixed-effect model. Mean concentrations of air pollutants such as ultrafine particles (UFP), black carbon (BC), carbon monoxide (CO), and nitrogen dioxide (NO2) were 2-3 times higher in the road than those in the park. Fifty-five lncRNAs [false discovery rate (FDR) < 0.05] including lncRNA NORAD, MALAT1, and H19 were changed in response to air pollution exposure. We found that 54 lncRNAs were associated with CO, 49 lncRNAs with UFP, 49 lncRNAs with BC, 48 lncRNAs with NO2, and 4 lncRNAs with PM2.5 (FDR < 0.05). These differential lncRNAs participated in dozens of pathways including cardiovascular signaling, epithelial cell proliferation, inflammation, and transforming growth factor. This trial for the first time profiled changes of human exosomal lncRNAs following air pollution. Our findings revealed multiple biological processes moderated by lncRNAs and provided epigenetic insights into cardiovascular effects of air pollution.

Parental PM2 .5 exposure changes Th17/Treg cells in offspring, is associated with the elevation of blood pressure.

Epidemiological evidences have indicated that fine particulate matter (PM2.5 ) exposure is associated with the occurrence and development of hypertension. The present study aims to explore the effects of parental PM2.5 exposure on blood pressure in offspring and elucidate the potential mechanism. The parental male and female C57BL/6 mice were exposed to concentrated PM2.5 or filtered air (FA) using Shanghai Meteorological and Environmental Animal Exposure System (Shanghai-METAS) for 16 weeks. At week 12, the mice were assigned to breed offspring. The male offspring mice were further exposed to PM2.5 or FA as above method. During the parental exposure, the average PM2.5 concentration was 133.7 ± 53.32 µg/m3 in PM chamber, whereas the average concentration in FA chamber was 9.4 ± 0.23 µg/m3 . Similarly, during the offspring exposure, the average concentration in PM and FA chamber were 100.76 ± 26.97 µg/m3 and 9.15 ± 0.15 µg/m3 , respectively. The PM2.5 -exposed offspring mice displayed the elevation of blood pressure, the increase of angiotensin II (Ang II), the decrease of angiotensin converting enzyme 2 (ACE2) and Ang (1-7) in serum when compared with the FA-exposed offspring mice. The similar results displayed in the proteins expression of ACE2, AT1R, and Ang (1-7) in vessel and kidney. More importantly, parental PM exposure further induced the increase in serous Ang II and the protein expression of AT1R in vessel, but decrease in ACE2 and Ang (1-7). The serous Ang II was positively associated with splenic T helper type 17 (Th17) cell population and serous IL (interleukin)-17A, but negatively associated with T regular (Treg) cell population and serous IL-10. The results suggested that parental air pollution exposure might induce the elevation of offspring blood pressure via mediate Th17- and Treg-related immune microenvironment.

Ambient fine particulate matter induced the elevation of blood pressure through ACE2/Ang(1-7) pathway: The evidence from urine metabolites.

BACKGROUND: Exposure to ambient fine particulate matter (PM2.5) is associated with various adverse health outcomes. Although several mechanisms have been proposed including oxidative stress and inflammatory responses, the exact mechanism is still unknown. Few studies have investigated the mechanism linking PM2.5 and blood pressure (BP). In this study, we measured urinary metabolites and BP -related renin-angiotensin-aldosterone system (RAAS) to investigate the associations between ambient PM2.5 exposure and BP in healthy C57BL/6 mice. METHODS: The C57BL/6 mice were exposed to ambient concentrated PM2.5 or filtered air (FA) for 16 weeks. Systolic BP and diastolic BP were measured by noninvasive BP system. The urine metabolites were quantified using the untargeted metabolomics approach. The expression of RAAS-related proteins angiotensin-converting enzyme (ACE)2, angiotensin (Ang) II, Ang (1-7) and aldosterone (ALD) were measured using Western blot and ELISA kits. RESULTS: The metabolomics analysis demonstrated that PM2.5 exposure induced significant changes of some metabolites in urine, including stress hormones, amino acids, fatty acids, and lipids. Furthermore, there was an elevation of BP, increase of serous Ang II and ALD, along with the decrease of ACE2 and Ang (1-7) in kidney in the PM2.5-exposed mice compared with FA-exposed mice. CONCLUSIONS: The results demonstrated that PM2.5 exposure-induced BP elevation might be associated with RAAS activation. Meanwhile, PM2.5 exposure-induced changes of stress hormone and lipid metabolism might mediate the activation of RAAS. The results suggested that the systemic stress hormone and lipid metabolism was associated with the development of hypertension.

Fine particulate matter-induced cardiovascular injury is associated with NLRP3 inflammasome activation in Apo E-/- mice.

Epidemiological evidences have indicated that fine particulate matter (PM2.5) is associated with the increased risk of cardiovascular morbidity and mortality. Although several mechanisms linking PM2.5 and inflammatory responses have been widely implicated, the detailed mechanisms involving the occurrence of inflammation in PM2.5-induced adverse effects are lacking. This study aims to investigate whether PM2.5 exposure-induced cardiovascular injury is associated with NLRP3 inflammasome activation in apolipoprotein E-/- (Apo E-/-) mice. Thirty-two Apo E-/- mice were randomly divided into four groups. The mice were fed with normal chow (NC) or high-fat chow (HFC) for 10 weeks, respectively. From week 11, the mice were exposed to concentrated PM2.5 (PM) or filter air (FA) using Shanghai Meteorological and Environmental Animal Exposure System for 16 weeks. The cardiac function and myocardial injury were evaluated by echocardiography and histopathological examination. Meanwhile, the expression of NLRP3-related signaling pathway in myocardium was detected. Compared with the FA mice, the PM mice showed the underlying cardiac dysfunction and injury in both NC and HFC groups. Mononuclear macrophages (CD11c+) were significant higher in bone marrow of the PM mice than that in the FA mice, whilst CD206+ macrophages were lower. Accordingly, PM2.5 exposure induced the increase of circulating inflammatory cytokine TNF-α and decrease of anti-inflammatory cytokine IL-10. PM2.5 exposure was also associated with the activation of NLRP3 inflammasome, which characterized by elevated protein expression of NLRP3, ASC, caspase-1, IL-1ß and IL-18 in myocardium. All these results demonstrated PM2.5-related cardiac injury is mediated by macrophages polarization and NLRP3 inflammasome activation.

AMPK activation attenuates inflammatory response to reduce ambient PM2.5-induced metabolic disorders in healthy and diabetic mice.

Epidemiological and experimental studies have indicated that ambient fine particulate matter (PM2.5) exposure is associated with the occurrence and development of metabolic disorders such as obesity and type 2 diabetes mellitus (T2DM). However, the mechanism is not clear yet, and there are few studies to explore the possible prevention measure. In this study, C57BL/6 and db/db mice were exposed to concentrated PM2.5 or filtered air using Shanghai Meteorological and Environmental Animal Exposure System (Shanghai-METAS) for 12 weeks. From week 11, some of the mice were assigned to receive a subcutaneous injection of AMPK activator (AICAR). Lipid metabolism, glucose tolerance, insulin sensitivity and energy homeostasis were measured. Meanwhile, the respiratory, systemic and visceral fat inflammatory response was detected. The results showed that PM2.5 exposure induced the impairments of glucose tolerance, insulin resistance, lipid metabolism disorders and disturbances of energy metabolism in both C57BL/6 and db/db mice. These impairments might be consistent with the increased respiratory, circulating and visceral adipose tissue (VAT) inflammatory response, which was characterized by the release of IL-6 and TNF-α in lung, serum and VAT. More importantly, AICAR administration led to the significant enhancement of energy metabolism, elevation of AMPK as well as the decreased IL-6 and TNF-α in VAT of PM2.5-exposed mice, which suggesting that AMPK activation might attenuate the inflammatory responses in VAT via the inhibition of MAPKs and NFκB. The study indicated that exposure to ambient PM2.5 under the concentration which is often seen in some developing countries could induce the occurrence of metabolic disorders in normal healthy mice and exacerbate metabolic disorders in diabetic mice. The adverse impacts of PM2.5 on insulin sensitivity, energy homeostasis, lipid metabolism and inflammatory response were associated with AMPK inhibition. AMPK activation might inhibit PM2.5-induced metabolic disorders via inhibition of inflammatory cytokines release. These findings suggested that AMPK activation is a potential therapy to prevent some of the metabolic disorders attributable to air pollution exposure.

The essential function of CARD9 in diet-induced inflammation and metabolic disorders in mice.

Inflammation and metabolic disorder are common pathophysiological conditions, which play a vital role in the development of obesity and type 2 diabetes. The purpose of this study was to explore the effects of caspase recruitment domain (CARD) 9 in the high fat diet (HFD)-treated mice and attempt to find a molecular therapeutic target for obesity development and treatment. Sixteen male CARD9-/- and corresponding male WT mice were fed with normal diet or high fat diet, respectively, for 12 weeks. Glucose tolerance, insulin resistance, oxygen consumption and heat production of the mice were detected. The CARD9/MAPK pathway-related gene and protein were determined in insulin-responsive organs using Western blotting and quantitative PCR. The results showed that HFD-induced insulin resistance and impairment of glucose tolerance were more severe in WT mice than that in the CARD9-/- mice. CARD9 absence significantly modified O2 consumption, CO2 production and heat production. CARD9-/- mice displayed the lower expression of p38 MAPK, JNK and ERK when compared to the WT mice in both HFD- and ND-treated groups. HFD induced the increase of p38 MAPK, JNK and ERK in WT mice but not in the CARD9-/- mice. The results indicated that CARD9 absence could be a vital protective factor in diet-induced obesity via the CARD9/MAPK pathway, which may provide new insights into the development of gene knockout to improving diet-induced obesity and metabolism disorder.

The severity of lung injury and metabolic disorders induced by ambient PM2.5 exposure is associated with cumulative dose.

Lots of epidemiological and experimental studies have found that ambient fine particulate matter (PM2.5) exposure is associated with the development of cardiopulmonary diseases, obesity and diabetes. This study focused on the effects of cumulative PM2.5 exposure on pulmonary and systemic inflammation and insulin resistance. Thirty-two 6-week-old male Balb/c mice were randomly divided into four groups (FA, PM, WEEK and DAY groups) and were continuously or intermittently exposed to concentrated PM2.5 or filtered air (FA) for four weeks using Shanghai Meteorological and Environmental Animal Exposure System ("Shanghai-METAS"). The levels of IL-6 and TNF-α in serum, bronchoalveolar lavage fluid (BALF), lung tissues and white adipose tissue (WAT) were measured. Meanwhile, the expression of NF-κB and phosphor-NF-κB in lung tissue was detected by Western blot. Glucose tolerance and insulin resistance were also determined at the end of exposure. The results found that the mice in PM group displayed moderate inflammatory cell infiltration in lung, whereas the mice in WEEK and DAY groups displayed slight inflammatory cell infiltration in lung. Compared with the mice in FA group, the mRNA expressions of IL-6 and TNF-α in lung tissue and WAT significantly increased in the mice of PM group. Importantly, IL-6 and TNF-α mRNA expressions in PM group were higher than those in WEEK and DAY groups. The protein expression of phospho-NF-κB in lung tissue showed that PM group showed the activation of NF-κB, which was higher than that in the WEEK and DAY groups. Meanwhile, the mice in PM group showed more severe glucose tolerance and insulin resistance than that in the WEEK and DAY groups. The results suggested that the reduction of PM2.5 cumulative exposure may alleviate pulmonary and adipose inflammation, insulin resistance and glucose tolerance impairment. The results provided a clue that the interruption of ambient PM2.5 exposures by systems such as indoor air purification could be of benefit to people's health.

[Effects of vitamin E and ω-3 fatty acids on protecting ambient PM_(2. 5)-induced cardiovascular injury].

OBJECTIVE: To observe whether vitamin E( Ve) and ω-3 polyunsaturated fatty acids( ω-3 FA) could prevent the fine particulate matter( PM_(2. 5))-induced cardiovascular injury and explore the potential mechanism. METHODS: The SD rats were assigned randomly to 8 groups, those were control group, PM_(2. 5)group, Ve treatment groups( 3, 10, 30 mg/( kg·d)) and ω-3 FA treatment groups( 10, 30 and 90 mg/( kg·d)). The rats were pretreated with different concentration of Ve and ω-3 FA separately for 14 days, then were exposed to ambient PM_(2. 5) by intratracheal instillation( 10 mg/kg BW). All the rats were sacrificed after the last PM_(2. 5) exposure, then the arterial blood, lungs and cardiac tissues were collected. The expressions of tumor necrosis factor-α( TNF-α), interleukin-1ß( IL-1ß), interleukin-6( IL-6) in serum, bronchoalveolar lavage fluid and supernatant of cardiac tissue were detected by ELISA kits. The levels of malondialdehyde( MDA), superoxide dismutase( SOD) and glutathione-peroxidase( GSH-Px) in serum and myocardium were also measured. RESULTS: Compared with the severe injury of rats in PM_(2. 5) exposure group, the rats in Ve or ω-3 FA groups had a slighter injury in lung and cardiac tissue with the increase of Ve and ω-3 FA. Similarly, the levels of IL-1ß, IL-6 in bronchoalveolar lavage fluid had a decreasing trend with the increase of Ve and ω-3 FA compared with the PM_(2. 5) exposure groups. Meanwhile, the expressions of TNF-α in Ve and ω-3 FA high dose groups were significantly reduced when compared with the PM_(2. 5) exposure group( P <0. 05). In addition, the MDA levels in serum were markedly decreased and the activities of SOD were significantly increased compared with the PM_(2. 5)exposure group( P < 0. 05 or P < 0. 01) whereas the SOD activities were elevated only in the ω-3 FA high dose groups( P < 0. 05). Meanwhile, the levels of IL-6 and TNF-α in serum had an obvious decrease compared with the PM_(2. 5) exposure group( P < 0. 01). Similarly, compared with the PM_(2. 5)exposure group, the expressions of MDA were markedly decreased and the activities of SOD and GSH-Px in myocardium were significantly increased( P < 0. 05 or P < 0. 01) in the Ve treatment group. In addition, the activities of GSH-Px was found higher only in the ω-3 FA high treatment group compared with the PM_(2. 5)exposure group( P < 0. 05). Meanwhile, the levels of IL-1ß and TNF-α in cardiac tissue had an obvious decrease trend with the increase of Ve and ω-3 FA. CONCLUSION: PM_(2. 5) exposure may increase inflammatory response and oxidative stress, supplementation with Ve and ω-3 FA could prevent the PM_(2. 5)-induced inflammatory reaction and oxidative stress damage by increasing the activities of SOD and GSH-Px.

Traffic-related air pollution is associated with cardio-metabolic biomarkers in general residents.

PURPOSE: The study was conducted to explore the mechanisms linking traffic-related air pollution and cardio-metabolic risk. METHODS: The participants included 371 men and women aged from 45 to 75 in an urban residential area in Shanghai, China. The participants were divided into four categories (≤50, 51-100, 101-200 and >200 m) according to the residential distance to major road. Additionally, the personal fine particulate matter (PM2.5) was measured from 8:00 am to 6:00 pm to assess the PM2.5 exposure in general residents. Then, the continuous subclinical measurements and biological effects related to cardio-metabolic disorders were detected. The generalized linear regression analysis was applied for estimating the adjusted hazards ratio for cardio-metabolic disorders relative to traffic-related air pollution. RESULTS: The average personal PM2.5 is 111.1 µg/m(3) in the participants living within 50 m to major road, which is significantly higher than the personal PM2.5 (68.2 µg/m(3)) in the participants living more than 200 m away from the major road. The participants living within 50 m to major road compared with those living more than 200 m away have 1.15 times higher of heart rate (HR), 1.95 times higher of fasting insulin, 1.30 times higher of homeostasis model assessment of insulin resistance (HOMA-IR), 1.56 times higher of low-density lipoprotein cholesterol (LDL-C), 8.39 times higher of interleukin 6 (IL-6), 4.30 times higher of augmentation index (AI), 1.60 times higher of systolic blood pressure (SBP) and 1.91 times higher of diastolic blood pressure (DBP). Contrary to the increase in above biological effects, there were 1.06 times lower of low frequency (LF), 1.05 times lower of high frequency (HF), 2.54 times lower of IL-10, 4.61 times lower of nitric oxide (NO), 1.19 times lower of superoxide dismutase (SOD) and 1.85 times lower of total antioxidant capacity (T-AOC). There was no clear exposure-response relationship can be observed in the fasting glucose, LF/HF, cholesterol and high-density lipoprotein (HDL). CONCLUSION: Long-term exposure to traffic-related air pollution may contribute to the development or exacerbation of cardio-metabolic disorders. The mechanisms linking air pollution and cardio-metabolic disorders may be associated with the increased systemic inflammation and oxidative stress, reduced insulin sensitivity and elevated arterial stiffness and blood pressure.

[Effects and mechanism of inflammation and energy metabolism in mice caused by PM_(2. 5) exposure].

OBJECTIVE: The current study was conducted to observe the effects of fine particles( PM_(2. 5)) on energy metabolism and inflammation. The potential mechanism linking PM_(2. 5)and type 2 diabetes was explored. METHODS: C57 BL /6 mice were randomly assigned to 2 groups. The mice in exposure group were intratracheal instilled of 15 mg / kg BW PM_(2. 5). The mice in control were instilled with saline. The instillation were conducted three times per week for 18 weeks. Insulin resistance test( ITT) and introperitoneal glucose tolerance test( IPGTT) were determined after the last exposure. The mRNA expression of IL-6, IL-17 A, MAPK, NF-κB and TNF-α were analyzed in liver and white adipose tissue. RESULTS: The body weight of mice in PM_(2. 5)group [( 24. 976 ± 0. 571) g] showed significant decrease compared to that in control mice [( 28. 452 ± 1. 520) g]( P < 0. 05). Blood glucose significantly increased in exposure group. The mice in exposure group showed insulin resistance and glucose tolerance impairment. The expression of IL-6 mRNAexpression in liver( 0. 373 ± 0. 185) and in white adipose tissue( 0. 364 ± 0. 089)increased along with the increase of TNF-α mRNA expression( 0. 008 ± 0. 002) in white adipose tissue. CONCLUSION: The PM_(2. 5)exposure may be associated with the development of diabetes. The potential mechanism could be the impaired glucose tolerance, elevated insulin resistance and the increase of inflammatory response.

Challenges of Air Pollution and Health in East Asia.

PURPOSE OF REVIEW: Air pollution has been a serious environmental and public health issue worldwide, particularly in Asian countries. There have been significant increases in epidemiological studies on fine particulate matter (PM2.5) and ozone pollution in East Asia, and an in-depth review of epidemiological evidence is urgent. Thus, we carried out a systematic review of the epidemiological research on PM2.5 and ozone pollution in East Asia released in recent years. RECENT FINDINGS: Recent studies have indicated that PM2.5 and ozone are the most detrimental air pollutants to human health, resulting in substantial disease burdens for Asian populations. Many epidemiological studies of PM2.5 and ozone have been mainly performed in three East Asian countries (China, Japan, and South Korea). We derived the following summary findings: (1) both short-term and long-term exposure to PM2.5 and ozone could raise the risks of mortality and morbidity, emphasizing the need for continuing improvements in air quality in East Asia; (2) the long-term associations between PM2.5 and mortality in East Asia are comparable to those observed in Europe and North America, whereas the short-term associations are relatively smaller in magnitude; and (3) further cohort and intervention studies are required to yield robust and precise evidence that can promote evidence-based policymaking in East Asia. This updated review presented an outline of the health impacts of PM2.5 and ozone in East Asia, which may be beneficial for the development of future regulatory policies and standards, as well as for designing subsequent investigations.

Lifestyle modifies the associations of early-life smoking behaviors and genetic susceptibility with type 2 diabetes: A prospective cohort study involving 433,872 individuals from UK Biobank.

BACKGROUND: To investigate whether and what lifestyle factors in later life modify the associations of early-life smoking behaviors and genetic susceptibility with type 2 diabetes (T2D). METHODS: In the UK Biobank, in utero tobacco exposure (n = 354,493) and age of smoking initiation (n = 353,557) were self-reported. A composite lifestyle score was calculated based on diet, physical activity, nicotine exposure, sleep duration, and BMI. Hazard ratio (HR) and absolute risk difference (ARD) were used to estimate the associations of early-life smoking behaviors and genetic risk with incident T2D, as well as the effect modification of the lifestyle score. RESULTS: During a median follow-up of 14.6 years, the HRs (95 % CIs) of T2D for in utero tobacco exposure, and smoking initiation in adulthood, adolescence, and childhood, compared with no smoking behavior, were 1.19 (1.16-1.23), 1.34 (1.29-1.39), 1.58 (1.53-1.64), 2.22 (2.11-2.32), respectively (P for trend<0.001). Early-life smoking behaviors and high genetic risk (vs no smoking behavior and low genetic risk) were associated with a 302%-593 % higher T2D risk (P for additive interaction<0.05). Compared to participants with early-life smoking behaviors, high genetic risk, and an unfavorable lifestyle, those who adhered to a favorable lifestyle had a lower T2D risk in all subgroups (HRs from 0.05 to 0.36 and ARD from -14.97 % to -9.51 %), with the highest ARD attributable to lifestyle in participants with early-life smoking behaviors and high genetic risk. CONCLUSIONS: The T2D risk associated with early-life smoking behaviors and genetic risk was modified by a favorable lifestyle.

Associations of Dietary Cholesterol Consumption With Incident Diabetes and Cardiovascular Disease: The Role of Genetic Variability in Cholesterol Absorption and Disease Predisposition.

OBJECTIVE: Whether genetic susceptibility to disease and dietary cholesterol (DC) absorption contribute to inconsistent associations of DC consumption with diabetes and cardiovascular disease (CVD) remains unclear. RESEARCH DESIGN AND METHODS: DC consumption was assessed by repeated 24-h dietary recalls in the UK Biobank. A polygenetic risk score (PRS) for DC absorption was constructed using genetic variants in the Niemann-Pick C1-Like 1 and ATP Binding Cassettes G5 and G8 genes. PRSs for diabetes, coronary artery disease, and stroke were also created. The associations of DC consumption with incident diabetes (n = 96,826) and CVD (n = 94,536) in the overall sample and by PRS subgroups were evaluated using adjusted Cox models. RESULTS: Each additional 300 mg/day of DC consumption was associated with incident diabetes (hazard ratio [HR], 1.17 [95% CI, 1.07-1.27]) and CVD (HR, 1.09 [95% CI, 1.03-1.17]), but further adjusting for BMI nullified these associations (HR for diabetes, 0.99 [95% CI, 0.90-1.09]; HR for CVD, 1.04 [95% CI, 0.98-1.12]). Genetic susceptibility to the diseases did not modify these associations (P for interaction ≥0.06). The DC-CVD association appeared to be stronger in people with greater genetic susceptibility to cholesterol absorption assessed by the non-high-density lipoprotein cholesterol-related PRS (P for interaction = 0.04), but the stratum-level association estimates were not statistically significant. CONCLUSIONS: DC consumption was not associated with incident diabetes and CVD, after adjusting for BMI, in the overall sample and in subgroups stratified by genetic predisposition to cholesterol absorption and the diseases. Nevertheless, whether genetic predisposition to cholesterol absorption modifies the DC-CVD association requires further investigation.

Mechanistic insights into cardiovascular effects of ultrafine particle exposure: A longitudinal panel study.

BACKGROUND: Ultrafine particle (UFP) has been linked with higher risks of cardiovascular diseases; however, the biological mechanisms remain to be fully elucidated. OBJECTIVES: This study aims to investigate the cardiovascular responses to short-term UFP exposure and the biological pathways involved. METHODS: A longitudinal panel study was conducted among 32 healthy, non-smoking young adults in Shanghai, China, who were engaged in five rounds of follow-ups between December 2020 and November 2021. Individual exposures were calculated based on the indoor and outdoor real-time measurements. Blood pressure, arterial stiffness, targeted biomarkers, and untargeted proteomics and metabolomics were examined during each follow-up. Linear mixed-effect models were applied to analyze the exposure and health data. The differential proteins and metabolites were used for pathway enrichment analyses. RESULTS: Short-term UFP exposure was associated with significant increases in blood pressure and arterial stiffness. For example, systolic blood pressure increased by 2.10 % (95 % confidence interval: 0.63 %, 3.59 %) corresponding to each interquartile increase in UFP concentrations at lag 0-3 h, while pulse wave velocity increased by 2.26 % (95 % confidence interval: 0.52 %, 4.04 %) at lag 7-12 h. In addition, dozens of molecular biomarkers altered significantly. These effects were generally present within 24 h after UFP exposure, and were robust to the adjustment of co-pollutants. Molecular changes detected in proteomics and metabolomics analyses were mainly involved in systemic inflammation, oxidative stress, endothelial dysfunction, coagulation, and disturbance in lipid transport and metabolism. DISCUSSION: This study provides novel and compelling evidence on the detrimental subclinical cardiovascular effects in response to short-term UFP exposure. The multi-omics profiling further offers holistic insights into the underlying biological pathways.

Cause-specific mortality and burden attributable to temperature variability in China.

BACKGROUND: Few large-scale, nationwide studies have assessed cause-specific mortality risks and burdens associated with temperature variability (TV). OBJECTIVE: To estimate associations between TV and cause-specific mortality and quantify the mortality burden in China. METHODS: Data on daily total and cause-specific mortality in 272 Chinese cities between 2013 and 2015 were recorded. TVs were computed as the standard deviations of daily minimum and maximum temperatures over a duration of 2 to 7 days. The time-series quasi-Poisson regression model with adjustment of the cumulative effects of daily mean temperature over the same duration was applied to evaluate the city-specific associations of TV and mortality. Then, we pooled the effect estimates using a random-effects meta-analysis and calculated the mortality burdens. RESULTS: Overall, TV showed significant and positive associations with total and cause-specific mortality. The TV-mortality associations were generally stronger when using longer durations. A 1 °C increase in TV at 0-7 days (TV0-7) was associated with a 0.79 % [95 % confidence interval (CI): 0.55 %, 0.96 %] increase in total mortality. Mortality fractions attributable to TV0-7 were 4.37 % for total causes, 4.75 % for overall cardiovascular disease, 4.37 % for coronary heart disease, 5.05 % for stroke, 8.28 % for ischaemic stroke, 1.08 % for haemorrhagic stroke, 6.93 % for respiratory disease, and 6.81 % for COPD, respectively. The mortality risk and burden were generally higher in the temperate monsoon zone, females, and elders. CONCLUSION: This nationwide study indicated that TV was an independent risk factor of mortality, and could result in significant burden for main cardiorespiratory diseases.

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 (FEV1), forced vital capacity (FVC), the ratio of FEV1 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 [-0.075L (95% CI: -0.138, -0.012), p=2.1×10-2] for FEV1 and -0.190L/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.

Characterization of plasma-derived exosomal miRNA changes following traffic-related air pollution exposure: A randomized, crossover trial based on small RNA sequencing.

BACKGROUND: The underlying mechanisms for health effects of traffic-related air pollution (TRAP) are still unclear. Small RNA sequencing (RNA-seq) in exosomes represents as a powerful approach to elucidate biological pathways in response to environmental exposure. We therefore aimed to explore impact of TRAP exposure on exosomal miRNAs. METHODS: We performed a randomized, crossover study among 35 healthy college students in Shanghai, China. Participants were randomly assigned to 4-hour exposure in a traffic-polluted Road and in a traffic-free Park, respectively, intermitted by a washout period (at least 2 weeks). RNA-seq was conducted to identify plasma-derived exosomal miRNAs and the differential miRNAs were explored using linear mixed-effect models. Pathway enrichment was conducted using ingenuity pathway analysis. Further, we validated several selected miRNAs by droplet digital PCR (ddPCR). RESULTS: The average concentrations of air pollutants including ultrafine particles, black carbon, nitrogen dioxide, and carbon dioxide were 2-3 times higher in the Road compared to those in the Park. We identified 271 exosomal miRNAs (212 up-regulated and 59 down-regulated) that were significantly associated with TRAP. We found 5 miRNAs with 242 experimentally validated mRNA targets that were involved in cardiovascular pathway, cytokine signaling, and immune response. The ddPCR analysis suggested that miR-3612, miR-21-5p, and miR-195-5p were significantly changed following TRAP exposure. CONCLUSIONS: For the first time this trial characterized the genome-wide changes of exosomal miRNA associated with TRAP exposure. The molecular profiling of exosomal miRNAs and "novel" associations of some miRNAs were useful for understanding on biological mechanisms for the adverse effects of TRAP.

Ozone exposure and blood transcriptome: A randomized, controlled, crossover trial among healthy adults.

RATIONALE: Transcriptome-wide analysis is powerful in studying systemic RNA changes following environmental exposures. However, impacts of ozone inhalation on circulating transcriptome have not yet been examined. OBJECTIVES: To explore the impact of acute ozone exposure on circulating transcriptome using RNA sequencing (RNA-seq). METHODS: We recruited 32 healthy young adults in a randomized, crossover, controlled exposure trial. Each participant completed two 2-h exposure sessions of ozone (200 ppb) and clean air, respectively. Blood samples were collected at the end of each session and were used for RNA-seq. The differentially expressed genes associated with ozone exposure were assessed using Bayesian adjusted statistics from linear models in the limma R package. RESULTS: A total of 29 participants finished this trial and donated their blood samples for transcriptome analysis. The average concentration of ozone was 7.8 ± 2.6 ppb under clean air and 201.1 ± 1.7 ppb under ozone exposure session. A total of 1899 genes were significantly changed (1067 up-regulated and 832 down-regulated) by ozone exposure at a false discovery rate < 0.05, in which 403 genes had a fold change of > 1.2 or < 0.8. The top 10 terms of biological processes showed that most of the differentially expressed genes were related to various functions, such as neutrophil degranulation, immune response, and neutrophil activation. Pathway enrichment analysis showed dozens of pathways were dysregulated after ozone exposure, including mitochondrial dysfunction, and glucocorticoid receptor signaling. CONCLUSION: For the first time this trial characterized the genome-wide changes of mRNA in response to ozone exposure. We identified a range of differentially expressed genes that were involved in dozens of biological processes and pathways, providing novel biological insights into the systemic health effects of ozone.

Dynamic molecular choreography induced by traffic exposure: A randomized, crossover trial using multi-omics profiling.

The biological mechanism of adverse health outcomes related to exposure to traffic-related air pollution (TRAP) needs elucidation. We conducted a randomized, crossover trial among healthy young students in Shanghai, China. Participants wore earplugs and were randomly assigned to a 4-hour walking treatment either along a traffic-polluted road or through a traffic-free park. We conducted untargeted analyses of plasma exosome transcriptomics, serum mass spectrometry-based proteomics, and serum metabolomics to evaluate changes in genome-wide transcription, protein, and metabolite profiles in 35 randomly selected participants. Mean personal exposure levels of ultrafine particles, black carbon, nitrogen dioxide, and carbon monoxide in the road were 2-3 times higher than that in the park. We observed 3449 exosome mRNAs, 58 serum proteins, and 128 serum metabolites that were significantly associated with TRAP. The multi-omics analysis showed dozens of regulatory pathways altered in response to TRAP, such as inflammation, oxidative stress, coagulation, endothelin-1 signaling, and renin-angiotensin signaling. We found that several novel pathways activated in response to TRAP exposure: growth hormone signaling, adrenomedullin signaling, and arachidonic acid metabolism. Our study served as a demonstration and proof of concept on the evidence that associated TRAP exposure with global molecular changes based on the multi-omics level.

Traffic-related air pollution and genome-wide DNA methylation: A randomized, crossover trial.

BACKGROUND: Traffic-related air pollution (TRAP) has been associated with changes in gene-specific DNA methylation. However, few studies have investigated impact of TRAP exposure on genome-wide DNA methylation in circulating blood of human. OBJECTIVE: To explore the association between TRAP exposure and genome-wide DNA methylation. METHODS: We conducted a randomized, crossover exposure trial among 35 healthy adults in Shanghai, China. All subjects were randomly allocated to a traffic-free park or a main road for consecutive 4 h, respectively. Blood genome-wide DNA methylation after each exposure session was measured by the Infinium Methylation EPIC BeadChip (850K). The differentially methylated CpGs loci associated with TRAP exposure were identified using linear mixed-effect model. RESULTS: The average concentrations of traffic-related air pollutants including black carbon, ultrafine particles, carbon dioxide, and nitrogen dioxide were 2-3 times higher in the road compared to those in the park. Methylation levels of 68 CpG loci were significantly changed (false discovery rate < 0.05) following TRAP exposure, among which 49 were hypermethylated and 19 were hypomethylated. The annotated genes based on the differential CpGs loci were related to pathways in cardiovascular signaling, cytokine signaling, immune response, nervous system signaling, and metabolism. CONCLUSIONS: We found that TRAP exposure was associated with DNA methylation in dozens of genes concerning cardiometabolic health. This trial for the first-time profiled genome-wide methylation changes induced by TRAP exposure using the 850K assay, providing epigenetic insights in understanding the cardiometabolic effects of TRAP exposure.