Cerebral cortex and blood transcriptome changes in mouse neonates prenatally exposed to air pollution particulate matter

Resveratrol mitigates miR-212-3p mediated progression of diesel exhaust-induced pulmonary fibrosis by regulating SIRT1/FoxO3

BACKGROUND

Diesel exhaust (DE) exposure contributes to the progression of chronic respiratory diseases and is associated with dysregulation of microRNA expression. The present study aims to investigate the involvement of miRNAs and target genes in DE-induced lung fibrosis.

METHODS

C57BL/6 mice were divided into three groups. Group 1 mice were exposed to filtered air (Control). Group 2 mice were exposed to DE for 30 min per day, 5 days per week, for 8 weeks (DE). Group 3 mice received DE exposure along with resveratrol on alternate days for the last 2 weeks (DE + RES). Mice were sacrificed to isolate RNA from lung tissue for miRNA microarray profiling. Bronchoalveolar lavage fluid and lung tissues were collected for cell count and biochemical analysis.

RESULTS

DE exposure resulted in differential expression of 28 miRNAs with fold change >2 (p < 0.05). The upregulated miR-212-3p was selected for further analysis. Consensus analysis revealed enrichment of SIRT1 in the FoxO pathway, along with a co-annotation of reduced body weight (p < 0.05). A549 cells transfected with a miR-212-3p inhibitor showed a dose-dependent increase in SIRT1 expression, indicating SIRT1 as a direct target. Treatment with resveratrol restored SIRT1 and miR-212-3p expression and led to a reduction in inflammatory cytokines (p < 0.05). The modulation of SIRT1 correlated negatively with macrophage infiltration, confirming its role in regulating cellular infiltration and lung inflammation. Fibronectin, alpha-SMA, and collagen levels were significantly decreased in DE + RES compared to DE group suggesting modulation of cellular functions and resolution of lung fibrosis. Furthermore, a significant decrease in FoxO3a and TGF-β gene expressions was observed upon resveratrol administration thereby downregulating pro-fibrotic pathway.

CONCLUSIONS

The present study demonstrates resveratrol treatment stabilizes SIRT1 gene expression by attenuating miR-212-3p in DE-exposed mice, leading to downregulation of TGF-β and FoxO3a expressions. The study highlights the therapeutic role of resveratrol in the treatment of DE-induced pulmonary fibrosis.

Air pollution, dementia, and lifespan in the socio-economic gradient of aging: perspective on human aging for planning future experimental studies

Air pollution (AirPoll) accelerates human aging, as assessed by increased adult mortality and earlier onset of cardiovascular diseases, and dementia. Socio-economic strata (SES) of wealth and education have parallel differences of mortality and these diseases. Children from impoverished homes differ in brain development at birth and in risk of early fat excess and hypertension. To further enhance the healthspan, biogerontologists may consider a wider range of environmental exposures from gestation through later life morbidity that comprise the Gero-Exposome. Experimental studies with rodents and nematodes document shared transcriptional responses to AirPoll. In rodents, AirPoll exposure activates gene systems for body-wide detoxification through Nrf2 and NFkB transcription factors that mediate multiple aging processes. Gestational environmental factors include maternal diet and exposure to AirPoll and cigarette smoke. Correspondingly, gestational exposure of mice to AirPoll increased adult body fat, impaired glucose clearance, and decreased adult neurogenesis in the hippocampus, a brain region damaged in dementia. Nematode larvae also respond to AirPoll with Alzheimer relevant responses. These experimental approaches could identify to interventions for expanded human health and longevity across SES gradients.

Long-term exposure to PM2.5 compositions and O3 and their interactive effects on DNA methylation of peripheral brain-derived neurotrophic factor promoter

This study examined the associations of long-term exposure to ambient fine particulate matter (PM2.5) compositions/ozone with methylation of peripheral brain-derived neurotrophic factor (BDNF) promoters. A total of 101 participants were recruited from a cohort in Shijiazhuang, Hebei province, China. They underwent baseline and follow-up surveys in 2011 and 2015. DNA methylation levels were detected by bisulfite-PCR amplification and pyrosequencing. Participants' three-year average levels of PM2.5 compositions and ozone were estimated. Bayesian kernel machine regression (BKMR) models were used to examine the joint effects of pollutants on methylation levels. Exposure to PM2.5 compositions and ozone mixtures at the 75th percentile was associated with increased methylation levels at CpG2 of BDNF promoter (203%, 95% CI: 89, 316) than the lowest level of exposure, and sulfate dominated the effect in the BKMR models.Our findings provide clues to the epigenetic mechanisms for the associations of PM2.5 compositions and ozone with BDNF.

Uncovering the link between air pollution and neurodevelopmental alterations during pregnancy and early life exposure: A systematic review

Air pollution plays, nowadays, a huge role in human's health and in the personal economy. Moreover, there has been a rise in the prevalence of neurodevelopmental disorders like the Autism Spectrum Disorder (ASD) in recent years. Current scientific studies have established a link between prenatal or perinatal exposure to environmental pollutants and ASD. This systematic review summarizes the current literature available about the relationship between exposure to air pollutants (particulate matter [PM], Second Organic Aerosols [SOA], Diesel Exhaust [DE], and Traffic Related Air Pollution [TRAP]) and neurodevelopmental disorders in preclinical models using rats and mice. The articles were selected and filtered using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) methodology, and bias-evaluated using the SYstematic Review Centre for Laboratory animal Experimentation (SYRCLE) tool. Overall, our findings suggest that air pollutants are associated with negative developmental outcomes characterized by ASD-like behaviors, abnormal biochemical patterns, and impaired achievement of developmental milestones in rodents. However, there is not sufficient information in certain domains to establish a clear relationship. Short phrases for indexing terms: Air pollution affects neurodevelopment; PM exposure modifies glutamate system; Prenatal exposure combined with postnatal affect more to behavioral / cognitive domain; Air pollution modifies social behavior in rodents; Cognitive deficits can be detected after gestational exposure to air pollution.

An Alzheimer’s Disease Patient-Derived Olfactory Stem Cell Model Identifies Gene Expression Changes Associated with Cognition

An early symptom of Alzheimer’s disease (AD) is an impaired sense of smell, for which the molecular basis remains elusive. Here, we generated human olfactory neurosphere-derived (ONS) cells from people with AD and mild cognitive impairment (MCI), and performed global RNA sequencing to determine gene expression changes. ONS cells expressed markers of neuroglial differentiation, providing a unique cellular model to explore changes of early AD-associated pathways. Our transcriptomics data from ONS cells revealed differentially expressed genes (DEGs) associated with cognitive processes in AD cells compared to MCI, or matched healthy controls (HC). A-Kinase Anchoring Protein 6 (AKAP6) was the most significantly altered gene in AD compared to both MCI and HC, and has been linked to cognitive function. The greatest change in gene expression of all DEGs occurred between AD and MCI. Gene pathway analysis revealed defects in multiple cellular processes with aging, intellectual deficiency and alternative splicing being the most significantly dysregulated in AD ONS cells. Our results demonstrate that ONS cells can provide a cellular model for AD that recapitulates disease-associated differences. We have revealed potential novel genes, including AKAP6 that may have a role in AD, particularly MCI to AD transition, and should be further examined.

Maternal PM2.5 exposure during gestation and offspring neurodevelopment: Findings from a prospective birth cohort study

Emerging data have suggested the potential role of prenatal PM_2.5 exposure as a neurotoxin for offspring. However, the existing results are equivocal, and no study has examined the effects of complex chemical constituents of the particular matter on offspring neurodevelopment. Therefore, in a prospective birth cohort study conducted in Jiangsu, China, we aimed to investigate the association between prenatal exposure to PM_2.5 and the neurodevelopment in infants, and further assess the effects of specific chemical constituents of PM_2.5. A total of 1531 children who had available data on daily prenatal PM_2.5 exposure and completed assessment on neurodevelopment at 1 year old were enrolled. We used the high-performance machine-learning model to estimate daily PM_2.5 exposure concentrations at 1 km × 1 km spatial resolution. The combined geospatial-statistical model was applied to evaluate average concentrations of six chemical constituents [organic matter (OM), black carbon (BC), sulfate (SO₄^2-), nitrate (NO₃^-), ammonium (NH₄⁺), and soil dust (Dust)]. The neurodevelopment of children was assessed using Bayley-III Screening Test. After adjusting for confounding factors, the risk of non-optimal gross motor development increased by 31 % for every 10 μg/m³ increase in average PM_2.5 exposure during gestation (aRR: 1.31; 95 % CI: 1.04, 1.64). Further analysis of PM_2.5 constituents showed that prenatally exposed to high SO₄^2- was associated with the risk of non-optimal gross motor development (aRR: 1.40; 95 % CI: 1.08, 1.81). Null associations were observed for the rest four neurodevelopment domains. Collectively, our study suggested that prenatal exposure to PM_2.5, particularly with high SO₄^2- concentration, was associated with children's non-optimal gross motor development at 1 year old. The short- and long-term influences of perinatal PM_2.5 exposure on children's neurodevelopment warrant further investigation.

Long-term ambient air pollution exposure and DNA methylation of peripheral brain-derived neurotrophic factor promoter

This study aimed to investigate the association between air pollutants and methylation of peripheral brain-derived neurotrophic factor (BDNF) promoters. A total of 101 individuals were recruited in this panel study. BDNF promoter methylation was detected by bisulfite-PCR amplification and pyrosequencing. Participants' exposure to air pollutants was estimated using a satellite-based random forests approach. A generalized estimated equation model with natural cubic splines was employed to examine the associations between air pollutants and BDNF promoter methylation levels. The associations between air pollution and BDNF promoter methylation showed nonlinear curves with threshold effects. The threshold concentration for the association of nitrogen dioxide (NO₂) with average methylation level was 59.7 μg/m³, and that for the association of particulate matter ≤ 1 µm in diameter (PM₁) with CpG2 methylation level was 70.9 μg/m³. The percent change of average methylation level at the 95th percentile of NO₂ against the threshold concentration was 43.25% (95%CI: 13.10%, 73.40%), and that of CpG2 methylation at the 95th percentile of PM₁ was 128.29% (95%CI: 43.27%, 213.31%). Overall, long-term exposures of PM₁, PM_2.5, PM₁₀, and NO₂ were associated with significant changes in BDNF promoter methylation levels with threshold effects.