Maternal Exposure to PM2.5 Affects Fetal Lung Development at Sensitive Windows

Associations of prenatal ambient air pollution exposures with asthma in middle childhood

We examined associations between prenatal fine particulate matter (PM2.5), nitrogen dioxide (NO2), and ozone (O3) exposures and child respiratory outcomes through age 8-9 years in 1279 ECHO-PATHWAYS Consortium mother-child dyads. We averaged spatiotemporally modeled air pollutant exposures during four fetal lung development phases: pseudoglandular (5-16 weeks), canalicular (16-24 weeks), saccular (24-36 weeks), and alveolar (36+ weeks). We estimated adjusted relative risks (RR) for current asthma at age 8-9 and asthma with recent exacerbation or atopic disease, and odds ratios (OR) for wheezing trajectories using modified Poisson and multinomial logistic regression, respectively. Effect modification by child sex, maternal asthma, and prenatal environmental tobacco smoke was explored. Across all outcomes, 95% confidence intervals (CI) included the null for all estimates of associations between prenatal air pollution exposures and respiratory outcomes. Pseudoglandular PM2.5 exposure modestly increased risk of current asthma (RRadj = 1.15, 95% CI: 0.88-1.51); canalicular PM2.5 exposure modestly increased risk of asthma with recent exacerbation (RRadj = 1.26, 95% CI: 0.86-1.86) and persistent wheezing (ORadj = 1.28, 95% CI: 0.86-1.89). Similar findings were observed for O3, but not NO2, and associations were strengthened among mothers without asthma. While not statistically distinguishable from the null, trends in effect estimates suggest some adverse associations of early pregnancy air pollution exposures with child respiratory conditions, warranting confirmation in larger samples.

Prenatal Exposure to Air Pollution and Respiratory Distress in Term Newborns: Results from the MIREC Prospective Pregnancy Cohort

BACKGROUND

Respiratory distress is the leading cause of neonatal morbidity and mortality worldwide, and prenatal exposure to air pollution is associated with adverse long-term respiratory outcomes; however, the impact of prenatal air pollution exposure on neonatal respiratory distress has not been well studied.

OBJECTIVES

We examined associations between prenatal exposures to fine particular matter (PM 2.5 ) and nitrogen dioxide (NO 2 ) with respiratory distress and related neonatal outcomes.

METHODS

We used data from the Maternal-Infant Research on Environmental Chemicals (MIREC) Study, a prospective pregnancy cohort (n = 2,001 ) recruited in the first trimester from 10 Canadian cities. Prenatal exposures to PM 2.5 (n = 1,321 ) and NO 2 (n = 1,064 ) were estimated using land-use regression and satellite-derived models coupled with ground-level monitoring and linked to participants based on residential location at birth. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) for associations between air pollution and physician-diagnosed respiratory distress in term neonates in hierarchical logistic regression models adjusting for detailed maternal and infant covariates.

RESULTS

Approximately 7 % of newborns experienced respiratory distress. Neonates received clinical interventions including oxygen therapy (6%), assisted ventilation (2%), and systemic antibiotics (3%). Two percent received multiple interventions and 4% were admitted to the neonatal intensive care unit (NICU). Median PM 2.5 and NO 2 concentrations during pregnancy were 8.81   μ g / m 3 and 18.02  ppb , respectively. Prenatal exposures to air pollution were not associated with physician-diagnosed respiratory distress, oxygen therapy, or NICU admissions. However, PM 2.5 exposures were strongly associated with assisted ventilation (OR per 1 - μ g / m 3 increase in PM 2.5 = 1.17 ; 95% CI: 1.02, 1.35), multiple clinical interventions (OR per 1 - μ g / m 3 increase in PM 2.5 = 1.16 ; 95% CI: 1.07, 1.26), and systemic antibiotics, (OR per 1 - μ g / m 3 increase in PM 2.5 = 1.12 ; 95% CI: 1.04, 1.21). These associations were consistent across exposure periods-that is, during prepregnancy, individual trimesters, and total pregnancy-and robust to model specification. NO 2 exposure was associated with administration of systemic antibiotics (OR per 1-ppb increase in NO 2 = 1.03 ; 95% CI: 1.00, 1.06).

DISCUSSION

Prenatal exposures to PM 2.5 increased the risk of severe respiratory distress among term newborns. These findings support the development and prioritization of public health and prenatal care strategies to increase awareness and minimize prenatal exposures to air pollution. https://doi.org/10.1289/EHP12880.

The developmental toxicity of PM2.5 on the early stages of fetal lung with human lung bud tip progenitor organoids

Exposure to air pollution has been proven to be associated with impaired fetal lung development. However, due to the lack of reliable human source models, it is still challenging to deeply understand the human fetal lung development under PM2.5 exposure. Here, we utilized human embryonic stem cell (hESC) line H9 to generate lung bud tip progenitor organoids (LPOs), a process that mimics early stages of fetal lung development including definitive endoderm (DE) formation, anterior foregut endoderm (AFE) differentiation and lung progenitor cell specification, to evaluate potential pulmonary developmental toxicity of PM2.5. We demonstrated that PM2.5 exposure the entire LPOs induction from hESCs significantly affected cellular proliferation of LPOs, and altered the expression of lung progenitor cell markers NKX2.1, SOX2 and SOX9, which are canonically defined subsequently proximal-distal airways specification. To explore the dynamic influences of PM2.5 exposure at different stages of LPOs specification, we also found that PM2.5 exposure significantly affected the expression of several transcriptional factors that are important for the differentiation of DE and AFE. Mechanistically, we suggested PM2.5-induced developmental toxicity to LPOs was partially linked with the Wnt/β-catenin signaling pathway. Therefore, our findings further emphasize the substantial health risks in the development of respiratory system associated with prenatal exposure to PM2.5.

Overview of PM2.5 and health outcomes: Focusing on components, sources, and pollutant mixture co-exposure

PM_2.5 varies in source and composition over time and space as a complicated mixture. Consequently, the health effects caused by PM_2.5 varies significantly over time and generally exhibit significant regional variations. According to numerous studies, a notable relationship exists between PM_2.5 and the occurrence of many diseases, such as respiratory, cardiovascular, and nervous system diseases, as well as cancer. Therefore, a comprehensive understanding of the effect of PM_2.5 on human health is critical. The toxic effects of various PM_2.5 components, as well as the overall toxicity of PM_2.5 are discussed in this review to provide a foundation for precise PM_2.5 emission control. Furthermore, this review summarizes the synergistic effect of PM_2.5 and other pollutants, which can be used to draft effective policies.

Prenatal PM2.5 exposure impairs spatial learning and memory in male mice offspring: from transcriptional regulation to neuronal morphogenesis

BACKGROUND

As one of the environmental risk factors for human health, atmospheric fine particulate matter (PM_2.5) contributes to cognitive deterioration in addition to respiratory and cardiovascular injuries. Recently, increasing evidence implicates that PM_2.5 inhalation can affect neurological functions in offspring, but the sex-specific outcomes and the underlying biological processes are largely unknown.

OBJECTIVES

To observe the influence of prenatal PM_2.5 exposure on cognitive performance in offspring, to elucidate the neuronal morphological alterations and possible transcriptional regulation based on mRNA-sequencing (mRNA-Seq) data after birth, and to determine the key components of PM_2.5 contributing to the adverse effects.

METHODS

Pregnant C57BL/6J mice were exposed to sterile saline or PM_2.5 suspension. Morris water maze test was used to assess the cognitive function in weanling offspring. Microscopic observation was applied to detect neuronal morphogenesis in vivo and in vitro. The cortex tissues from male offspring were collected on postnatal days (PNDs) 1, 7, and 21 for mRNA-Seq analysis. The organic and inorganic components of PM_2.5 were separated to assess their contributions using primary cultured neurons.

RESULTS

Prenatal PM_2.5 exposure impaired spatial learning and memory in weanling male mice, but not female mice. The sex-specific outcomes were associated with mRNA expression profiles of the cortex during postnatal critical windows, and the annotations in Gene Ontology (GO) of differentially expressed genes (DEGs) revealed that the exposure persistently disrupted the expression of genes involved in neuronal features in male offspring. Consistently, axonal growth impairment and dendritic complexity reduction were observed. Importantly, Homeobox A5 (Hoxa5), a critical transcription factor regulating all of the neuronal morphogenesis-associated hub genes on PNDs 1, 7, and 21, significantly decreased in the cortex of male offspring following PM_2.5 exposure. In addition, both inorganic and organic components were harmful to axonal and dendritic growth, with organic components exhibiting stronger inhibition than inorganic ones.

CONCLUSION

Prenatal PM_2.5 exposure affected spatial learning and memory in male mice by disrupting Hoxa5-mediated neuronal morphogenesis, and the organic components, including polycyclic aromatic hydrocarbons (PAHs), posed more adverse effects than the inorganic components.

Exploration of the damage and mechanisms of BPS exposure on the uterus and ovary of adult female mice

Bisphenol S (BPS) has been followed with interest for its endocrine disrupting effects, but exploration on the reproductive system of adult females is lack of deep investigation. In the present study, adult female CD-1 mice were treated with BPS for 28 days at 300 μg/kg/day. After that, uteruses and ovaries were harvested for histopathological examination, RNA-seq analysis, and diseases risk prediction. Hematoxylin-eosin (H&E) staining results showed significant histological alterations in the uterus and ovary of the BPS-exposed mice. Bioinformatics analysis of the RNA-seq screened a certain number of differentially expressed genes (DEGs) in both uterus and ovary between BPS group and their corresponding vehicle control groups (Veh), respectively. Functional enrichment analysis of DEGs found that hormone metabolism and immunoinflammatory related pathways were enriched. Disease risk evaluation of the hub genes was performed and the results indicated that diseases associated with uterus and ovary were mainly related to tumors and cancers. Further pan cancer and ovarian cancer survival analysis based on human diseases database pointed out, Foxa1, Gata3, S100a8 and Shh for uterus, Itgam, Dhcr7, Fdps, Hmgcr, Hsd11b1, Hsd3b1, Ptges, F3, Fn1, Ptger4 and Srd5a1 for ovary were significant correlation with cancer. The findings suggest that BPS causes some histopathological changes, alters the expressions of hub genes, enhances uterine and ovarian tumors or even cancer risks.

Ambient fine particulate matter exposures and human early placental inflammation

The effect of fine particulate matter (PM_2.5) on human early maternal-fetal interface is unknown. We explored the association between maternal exposure to ambient PM_2.5 and inflammation in placental villus of 114 women with clinically recognized early pregnancy loss (CREPL) and 114 women with normal early pregnancy (NEP). Temporally-adjusted land use regression models were used to estimate maternal daily PM_2.5 exposure during pregnancy. Villus interleukin-1beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were measured using multiplex cytokines detection platform. Single-day lag effect of PM_2.5 exposure within ten days before early placental villus collection was estimated using multivariable linear regression model. Distributed lag and net cumulative effects of PM_2.5 exposures within ten and 30 days before villus collection, as well as five single weeks during the periovulatory period, were estimated using distributed lag non-linear models. In all 228 subjects, after adjusting for group (CREPL or NEP), temporal confounders, and demographic characteristics, both single-day and distributed lag effects of PM_2.5 exposure at lag 8 significantly increased villus IL-6; distributed lag effects of PM_2.5 exposure in the first and second weeks before ovulation increased IL-1β, and PM_2.5 exposure in the third week after ovulation increased IL-6 and TNF-α. In CREPL, single-day lag effect significantly increased IL-1β (at lag 1), IL-6 (at lag 8), and TNF-α (at lag 5); distributed lag effect increased IL-6 (at lag 4-lag 8) and TNF-α (at lag 4-lag 6); and cumulative effect within ten days before villus collection increased IL-6. There was no statistically significant cumulative effect in NEP. In summary, maternal PM_2.5 exposure was associated with placental inflammation in human early pregnancy, particularly with increased villus IL-6 in CREPL. Whether maternal-fetal interface inflammation related to PM_2.5 exposure during the periovulatory period or later contributes to CREPL or other adverse pregnancy outcomes requires further study.

Epigenome-wide association of neonatal methylation and trimester-specific prenatal PM2.5 exposure

Exposure to particulate matter with an aerodynamic diameter smaller than 2.5 microns (PM_2.5) can affect birth outcomes through physiological pathways such as inflammation. One potential way PM_2.5 affects physiology could be through altering DNA methylation (DNAm). Considering that exposures during specific windows of gestation may have unique effects on DNAm, we hypothesized a timing-specific association between PM_2.5 exposure during pregnancy and DNAm in the neonatal epithelial-cell epigenome.

Time series of transcriptome analysis in entire lung development stages provide insights into the origin of NO2 related lung diseases

Lung growth is a critical window, when exposure to various pollutants can disturb the finely-tuned lung development and enhance risk of long-term structural and functional sequelae of lung. In this study, pregnant C57/6 mice were treated with NO2, and lungs of fetus/offspring were collected at different developmental windows and dynamic lung development was determined. The results showed that maternal NO2 exposure suppressed fetal weight, implying that fetal development can be disturbed. The time-series RNA-seq analysis of lungs showed that maternal NO2 exposure induced significant time-dependent changes in the expression profiles of genes associated with lung vein myocardium development in fetus/offspring. Most of these genes in NO2 exposure group were suppressed at middle gestation and at birth. Our results also indicated that the gene expressions of Nkx2.5 in NO2 exposure were suppressed to 0.27- and 0.44-fold of the corresponding Air group at E13.5 and PND1, and restored at later time points. This indicated that the transcription factor Nkx2.5 played an important role in abnormal lung development in fetus/offspring caused by maternal NO2 exposure. Importantly, gene expressions of lung vein myocardium development were related to transcription factors (TFs) and lung functions, and TFs showed similar trends with lung function. These results provide a comprehensive view of the adverse effects of maternal NO2 exposure on fetal lung development by uncovering molecular targets and related signaling pathways at the transcriptional level.

Ambient fine particulate matter exposure disrupts placental autophagy and fetal development in gestational mice

Recent studies have shown that some adverse pregnancy outcomes, especially intrauterine growth restriction (IUGR), are associated with gestational exposure to ambient fine particulate matter (PM_2.5). However, potential mechanism remains to be elucidated. In the present study, pregnant C57BL/6 mice were randomly assigned to be exposed to either filtered air or ambient PM_2.5 in the gestation period via a concentrated whole-body exposure system. We found that gestational PM_2.5 exposure exerted no effect on implantation, preterm delivery, as well as fetal resorption and death. However, in utero fetal exposure to PM_2.5 showed a significant reduction in body weight and crown-rump length on GD13 and GD18. Meanwhile, maternal blood sinusoid in placenta was markedly reduced along with abnormal expression of placental nutrient transporters and growth hormone in dams exposed to PM_2.5. Additional tests showed gestational PM_2.5 exposure decreased autophagy-related protein levels and inhibited autophagy flux mainly on GD15. Correspondingly, AMPK/mTOR signaling pathway, a critical negative regulator of autophagy, was activated in placenta on GD15 by PM_2.5 exposure as well. These findings provide evidences that placental developmental disorder caused by autophagy inhibition might be an important mechanism for the growth restriction caused by PM_2.5 exposure.

Bisphenol A Analogs Induce Cellular Dysfunction in Human Trophoblast Cells in a Thyroid Hormone Receptor-Dependent Manner: In Silico and In Vitro Analyses

Bisphenol A (BPA) and its analogs are frequently detected in human daily necessities and environmental media. Placental thyroid hormone plays an important role in fetal development. Herein, we followed the adverse outcome pathway (AOP) to explore the toxic mechanisms of BPA and its analogs toward placental thyroid hormone receptor (TR). First, the TOX21 database was used, and the interactions between BPA analogs and the ligand-binding domains (LBDs) of two subtypes of TR (TRα and TRβ) were subjected to in silico screening using molecular docking (MD) and molecular dynamics simulation (MDS). Fluorescence spectra and circular dichroism (CD) showed that BPA and its analogs interfere with TRs as a molecular initiation event (MIE), including static fluorescence quenching and secondary structural content changes in TR-LBDs. Key events (KEs) of the AOP, including the toxicity induced in placental chorionic trophoblast cells (HTR-8/SVneo) by an inverted U-shaped dose effect and changes in ROS levels, were tested in vitro. BPA, BPB, and BPAF significantly changed the expression level of TRβ, and only BPAF significantly downregulated the expression level of TRα. In conclusion, our study contributes to the health risk assessment of BPA and its analogs regarding placental adverse outcomes (AOs).

Early diagnostic value of C-reactive protein as an inflammatory marker for moderate-to-severe bronchopulmonary dysplasia in premature infants with birth weight less than 1500 g

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a serious respiratory complication in premature infants and moderate-to-severe BPD may affect the long-term quality of life and lack of specific treatment once it happened. Therefore, it is necessary to identify early diagnostic biomarkers for moderate-to-severe BPD.

METHODS

This retrospective cohort study included all premature infants with birth weight <1500 g from March 1, 2015 to June 30, 2017. Patients were categorized into mild BPD, moderate-to-severe BPD and non BPD groups. Data collected included patient characteristics, C-reactive protein (CRP) tested at six time points, including 1d (2 h after birth and before the first feeding), 3d, 7d, 2w, 3w, and 4w after birth, and maternal factors. Ordinal regression analysis was used to identify independent predictors of moderate-to-severe BPD and receiver operating characteristic (ROC) curve was used to evaluate the value of CRP as an early diagnostic marker for moderate-to-severe BPD.

RESULTS

A total of 831 patients were recruited. BPD occurred in 156/831 premature infants with birth weight less than 1500 g. Lower birth weight (OR = 0.998, 95% CI 0.997-0.999, P = 0.004), higher CRP level 3 days after birth (OR = 1.287, 95% CI 1.195-1.384, P = 0.000), and hemodynamically significant patent ductus arteriosus (HsPDA) (OR = 12.256, 95% CI 3.766-39.845, P = 0.000) were independent risk factors for moderate-to-severe BPD. The area under curve of the CRP level 3 days after birth for diagnosing moderate-to-severe BPD was 0.867 (95% CI, 0.823-0.912, P = 0.000). The sensitivity was 83.0% and the specificity was 78.3% when the cut-off value was set at 4.105 mg/L.

CONCLUSION

The CRP level 3 days after birth may be used as an early diagnostic marker for moderate-to-severe BPD in preterm infants who have the risk factors for BPD with birth weight less than 1500 g.

Release of inhalable particles and viable microbes to the air during packaging peeling: Emission profiles and mechanisms

Packaging is necessary for preserving and delivering products and has significant impacts on human health and the environment. Particle matter (PM) may be released from packages and transferred to the air during a typical peeling process, but little is known about this package-to-air migration route of particles. Here, we investigated the emission profiles of total and biological particles, and the horizontal and vertical dispersion abilities and community structure of viable microbes released from packaging to the air by peeling. The results revealed that a lot of inhalable particles and viable microbes were released from package to the air in different migration directions, and this migration can be regulated by several factors including package material, effective peeling area, peeling speed and angles, as well as the characteristics of the migrant itself. Dispersal of package-borne viable microbes provides direct evidence that viable microbes, including pathogens, can survive the aerosolization caused by peeling and be transferred to air over different distances while remaining alive. Based on the experimental data and visual proof in movies, we speculate that nonbiological particles are package fibers fractured and released to air by the external peeling force exerted on the package and that microbe dispersal is attributed to surface-borne microbe suspension by vibration caused by the peeling force. This investigation provides new information that aerosolized particles can deliver package-borne substances and viable microbes from packaging to the ambient environment, motivating further studies to characterize the health effects of such aerosolized particles and the geographic migration of microbes via packaging.

Assessment on the lung injury of mice posed by airborne PM2.5 collected from developing area in China and associated molecular mechanisms by integrated analysis of mRNA-seq and miRNA-seq

Some epidemiological evidences showed exposure of airborne fine particulate matter (PM2.5) was associated with lung dysfunction. However, the adverse effects of PM2.5 from mid-scale city of China on the respiratory system were unknown. Correspondingly, the mechanisms, especially the epigenetic mechanism regulated by miRNAs, involved in PM2.5-induced lung injury has not been fully understood. In this study, male Balb/C mice were exposed to PM2.5 collected from mid-scale city (Baoji), China for 8 weeks (mean concentration 298.52 ± 25.86 μg/m3 at exposure chamber) using a whole-body exposure system. The carbon component was the main ingredient (45.80%) of PM2.5 followed by ions (43.19%). Meanwhile, the sum concentrations of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes (C18-C33) were 570.48 and 2029.13 ng/m3 in the exposure chamber, respectively. Obvious lung injury including pulmonary inflammation and fibrosis (p < 0.05 compared with the control) were found from PM2.5 exposure group determined by micro-CT and histopathological assays, respectively, suggesting the health risk posed by PM2.5 from mid-scale city of China should be concerned. The integrated analysis between mRNA-seq and miRNA-seq revealed the differentially expression genes in lung tissues were enriched in immune pathways including B cell receptor signaling (p = 0.078) and cell adhesion molecules (CAMs) (p = 0.0068). The expression profiles of the genes and corresponding mRNAs involved into the immune pathways determined by RT-qPCR analysis were consistent with them conducted by transcriptome. Moreover, the expression levels of the proteins (i.e., CD19, CD81, PIK3CD, and CD22) involved into B cell receptor signaling pathway from exposure group were 1.71- to 6.948- folds compared with the control, validating the results of the genes expression profiles. Further, canonical correlation analysis (CCA) and multiple correlation analysis between the target genes and components of PM2.5 documented the organic compounds (i.e., Benzo(a)pyrene (p = 0.012) and octadecane (p = 0.05)) and inorganic elements (i.e., Cl-, Ti, Al, and Zn) was the key environmental factors. Cd19, Pik3cd, and Cd8b1 might be the key genes for lung dysfunction induced by PM2.5 illuminated using interactive analysis (p < 0.05). This work for the first time showed the adverse effects of PM2.5 in mid-scale city in China on respiratory system should be concerned, and the associated epigenetic mechanism regulated by miRNA were revealed. These results may provide new insight into the development of future assessment on the air pollution associated respiratory disease.

Environmental Air Pollutants Inhaled during Pregnancy Are Associated with Altered Cord Blood Immune Cell Profiles

Air pollution exposure during pregnancy may be a risk factor for altered immune maturation in the offspring. We investigated the association between ambient air pollutants during pregnancy and cell populations in cord blood from babies born to mothers with asthma enrolled in the Breathing for Life Trial. For each patient (n = 91), daily mean ambient air pollutant levels were extracted during their entire pregnancy for sulfur dioxide (SO₂), nitric oxide, nitrogen dioxide, carbon monoxide, ozone, particulate matter <10 μm (PM₁₀) or <2.5 μm (PM_2.5), humidity, and temperature. Ninety-one cord blood samples were collected, stained, and assessed using fluorescence-activated cell sorting (FACS). Principal Component (PC) analyses of both air pollutants and cell types with linear regression were employed to define associations. Considering risk factors and correlations between PCs, only one PC from air pollutants and two from cell types were statistically significant. PCs from air pollutants were characterized by higher PM_2.5 and lower SO₂ levels. PCs from cell types were characterized by high numbers of CD8 T cells, low numbers of CD4 T cells, and by high numbers of plasmacytoid dendritic cells (pDC) and low numbers of myeloid DCs (mDCs). PM_2.5 levels during pregnancy were significantly associated with high numbers of pDCs (p = 0.006), and SO₂ with high numbers of CD8 T cells (p = 0.002) and low numbers of CD4 T cells (p = 0.011) and mDCs (p = 4.43 × 10⁻⁶) in cord blood. These data suggest that ambient SO₂ and PM_2.5 exposure are associated with shifts in cord blood cell types that are known to play significant roles in inflammatory respiratory disease in childhood.

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.

Fetotoxicity of Nanoparticles: Causes and Mechanisms

The application of nanoparticles in consumer products and nanomedicines has increased dramatically in the last decade. Concerns for the nano-safety of susceptible populations are growing. Due to the small size, nanoparticles have the potential to cross the placental barrier and cause toxicity in the fetus. This review aims to identify factors associated with nanoparticle-induced fetotoxicity and the mechanisms involved, providing a better understanding of nanotoxicity at the maternal–fetal interface. The contribution of the physicochemical properties of nanoparticles (NPs), maternal physiological, and pathological conditions to the fetotoxicity is highlighted. The underlying molecular mechanisms, including oxidative stress, DNA damage, apoptosis, and autophagy are summarized. Finally, perspectives and challenges related to nanoparticle-induced fetotoxicity are also discussed.

Maternal PM2.5 exposure and abnormal placental nutrient transport

Epidemiological studies of human and animal experiments indicated that gestational exposure to atmospheric pollutants could be followed by the abnormal placental development. However, the effects of this exposure on the placental transportation for nutrients have not been systematically investigated. In this study, fine particulate matters (PM_2.5) samples were collected in Taiyuan and pregnant rodent models were administered with 3 mg/kg b.w. PM_2.5 by oropharyngeal aspiration every other day starting on embryonic day 0.5 (E0.5). Then the pregnant mice were sacrificed and their placentas were collected at different time points. The results showed that maternal PM_2.5 exposure (MPE) disrupted the expression of proliferating cell nuclear antigen (PCNA) at all time points and inhibited the cell proliferation in placenta. Following that, the capacity for placental nutrient transport was impaired. The changes at E18.5 were observed most significantly, showing the altered mRNA expression of amino acid, long-chain polyunsaturated fatty acid (LCPUFA), glucose and folate transporters. In addition, the glycogen content was elevated at E18.5, and the triglyceride content was increased at E13.5 and E15.5 and decreased at E18.5 in the placenta after MPE. In a word, the adverse effect induced by MPE revealed that MPE led tothe disruption on the nutrient supply to the developing fetus via modulating the abundance of placental nutrient transporters (PNT).

Diesel Particulate Matter 2.5 Induces Epithelial-to-Mesenchymal Transition and Upregulation of SARS-CoV-2 Receptor during Human Pluripotent Stem Cell-Derived Alveolar Organoid Development

Growing evidence links prenatal exposure to particulate matter (PM2.5) with reduced lung function and incidence of pulmonary diseases in infancy and childhood. However, the underlying biological mechanisms of how prenatal PM2.5 exposure affects the lungs are incompletely understood, which explains the lack of an ideal in vitro lung development model. Human pluripotent stem cells (hPSCs) have been successfully employed for in vitro developmental toxicity evaluations due to their unique ability to differentiate into any type of cell in the body. In this study, we investigated the developmental toxicity of diesel fine PM (dPM2.5) exposure during hPSC-derived alveolar epithelial cell (AEC) differentiation and three-dimensional (3D) multicellular alveolar organoid (AO) development. We found that dPM2.5 (50 and 100 μg/mL) treatment disturbed the AEC differentiation, accompanied by upregulation of nicotinamide adenine dinucleotide phosphate oxidases and inflammation. Exposure to dPM2.5 also promoted epithelial-to-mesenchymal transition during AEC and AO development via activation of extracellular signal-regulated kinase signaling, while dPM2.5 had no effect on surfactant protein C expression in hPSC-derived AECs. Notably, we provided evidence, for the first time, that angiotensin-converting enzyme 2, a receptor to mediate the severe acute respiratory syndrome coronavirus clade 2 (SARS-CoV-2) entry into target cells, and the cofactor transmembrane protease serine 2 were significantly upregulated in both hPSC-AECs and AOs treated with dPM2.5. In conclusion, we demonstrated the potential alveolar development toxicity and the increase of SARS-Cov-2 susceptibility of PM2.5. Our findings suggest that an hPSC-based 2D and 3D alveolar induction system could be a useful in vitro platform for evaluating the adverse effects of environmental toxins and for virus research.