Maternal NO2 exposure induces cardiac hypertrophy in male offspring via ROS-HIF-1α transcriptional regulation and aberrant DNA methylation modification of Csx/Nkx2.5

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.

Effects of parental environmental copper stress on offspring development: DNA methylation modification and responses of differentially methylated region-related genes in transcriptional expression

Parental environmental copper (Cu) exposure is widespread, causing problems for sustainability of fish populations, and epigenetics is suggested to be fundamental during the process, but the mechanism is scarcely reported. Here, we describe the effects of parental environmental Cu exposure on zebrafish developmental abnormality in subsequent generation. This study demonstrated for the first time that: 1. offspring from Cu-stressed paternal adult zebrafish showed developmental defects in the nervous and digestive system and changes in transcriptome; 2. Cu-induced alterations in sperm methylome and transcriptome could induce loci-specific alterations in DNA methylome and corresponding changes in the related gene transcription in offspring; 3. differentially methylated regions in pmpcb, crebl2 and tab2 promoters acted pivotally in their transcription; 4. pmpcb, crebl2 and tab2 are key individual contributors to parental Cu exposure-induced developmental defects in the nervous system, retina and digestive system of the offspring. Those data revealed that Cu-induced alterations in sperm methylome and transcriptome can be passed down to their fertilized offspring, reprogramming the epigenetic and transcriptional regulation of embryogenesis and causing embryonic developmental defects, suggesting that environmental Cu might pose a huge threat to the sustainability of fish populations.

Associations between air pollutant exposure and renal function: A prospective study of older adults without chronic kidney disease

We used real-world exposure scenarios to evaluate the effect of six ambient air pollutant (PM_2.5, PM₁₀, NO₂, SO₂, CO, and O₃) exposure on renal function among older adults without chronic kidney disease (CKD). We recruited 169 older adults without CKD in Beijing, China, for a longitudinal study from 2016 to 2018. The Modification of Diet in Renal Disease (MDRD) and the Chronic Kidney Disease Epidemiology Collaboration (EPI) equations were employed to derive the estimated glomerular filtration rate (eGFR). A linear mixed-effects model with random intercepts for participants was employed to determine the effects of air pollutants on renal function evaluated on the basis of eGFR and urinary albumin/creatinine ratio at different exposure windows (1-, 2-, 3-, 5-, 7-, 14-, 28-, 45-, and 60-days moving averages). An interquartile range (IQR) increase in NO₂ for was associated with significant decreases of in eGFR (MDRD equation) [percentage changes: -4.49 (95% confidence interval: -8.44, -0.37), -5.51 (-10.43, -0.33), -2.26 (-4.38, -0.08), -3.71 (-6.67, -0.65), -5.44 (-9.58, -1.11), -5.50 (-10.24, -0.51), -6.15 (-10.73, -1.33), and -6.34 (-11.17, -1.25) for 1-, 2-, 5-, 7-, 14-, 28-, 45-, and 60-days moving averages, respectively] and in eGFR (EPI equation) [percentage changes: -5.04 (-7.09, -2.94), -6.25 (-8.81, -3.62), -5.16 (-7.34, -2.92), -5.10 (-7.85, -2.28), -5.83 (-8.23, -3.36), -6.04 (-8.55, -3.47) for 1-, 2-, 14-, 28-, 45-, and 60-days moving averages, respectively]. In two-pollutant model, only the association of NO₂ exposure with eGFR remained robust after adjustment for any other pollutant. This association was stronger for individuals with hypertension for the EPI equation or BMI <25 kg/m² for the MDRD equation at lags 1 and 1-2. Our findings suggest that NO₂ exposure is associated with eGFR reduction among older adults without CKD for short (1-, 2-days) and medium (14-, 28-, 45-, 60-days) term exposure periods; thus, NO₂ exposure may contribute to renal impairment.

Expression of farnesyl pyrophosphate synthase is increased in diabetic cardiomyopathy

Farnesyl pyrophosphate synthase (FPPS)-catalyzed isoprenoid intermediates are involved in diabetic cardiomyopathy. This study investigated the specific role of FPPS in the development of diabetic cardiomyopathy. We demonstrated that FPPS expression was elevated in both in vivo and in vitro models of diabetic cardiomyopathy. FPPS inhibition decreased the expression of proteins related to cardiac fibrosis and cardiomyocytic hypertrophy, including collagen I, collagen III, connective tissue growth factor, natriuretic factor, brain natriuretic peptide, and β-myosin heavy chain. Furthermore, FPPS inhibition and knockdown prevented phosphorylated c-Jun N-terminal kinase 1/2 (JNK1/2) activation in vitro. In addition, a JNK1/2 inhibitor downregulated high-glucose-induced responses to diabetic cardiomyopathy. Finally, immunofluorescence revealed that cardiomyocytic size was elevated by high glucose and was decreased by zoledronate, small-interfering farnesyl pyrophosphate synthase (siFPPS), and a JNK1/2 inhibitor. Taken together, our findings indicate that FPPS and JNK1/2 may be part of a signaling pathway that plays an important role in diabetic cardiomyopathy.

Oxidative stress in cardiac hypertrophy: From molecular mechanisms to novel therapeutic targets

When faced with increased workload the heart undergoes remodelling, where it increases its muscle mass in an attempt to preserve normal function. This is referred to as cardiac hypertrophy and if sustained, can lead to impaired contractile function. Experimental evidence supports oxidative stress as a critical inducer of both genetic and acquired forms of cardiac hypertrophy, a finding which is reinforced by elevated levels of circulating oxidative stress markers in patients with cardiac hypertrophy. These observations formed the basis for using antioxidants as a therapeutic means to attenuate cardiac hypertrophy and improve clinical outcomes. However, the use of antioxidant therapies in the clinical setting has been associated with inconsistent results, despite antioxidants having been shown to exert protection in several animal models of cardiac hypertrophy. This has forced us to revaluate the mechanisms, both upstream and downstream of oxidative stress, where recent studies demonstrate that apart from conventional mediators of oxidative stress, metabolic disturbances, mitochondrial dysfunction and inflammation as well as dysregulated autophagy and protein homeostasis contribute to disease pathophysiology through mechanisms involving oxidative stress. Importantly, novel therapeutic targets have been identified to counteract oxidative stress and attenuate cardiac hypertrophy but more interestingly, the repurposing of drugs commonly used to treat metabolic disorders, hypertension, peripheral vascular disease, sleep disorders and arthritis have also been shown to improve cardiac function through suppression of oxidative stress. Here, we review the latest literature on these novel mechanisms and intervention strategies with the aim of better understanding the complexities of oxidative stress for more precise targeted therapeutic approaches to prevent cardiac hypertrophy.

The role and molecular mechanism of epigenetics in cardiac hypertrophy

Cardiac hypertrophy is a significant risk factor for cardiovascular disease, including heart failure, arrhythmia, and sudden death. Cardiac hypertrophy involves both embryonic gene expression and transcriptional reprogramming, which are tightly regulated by epigenetic mechanisms. An increasing number of studies have demonstrated that epigenetics plays an influential role in the occurrence and development of cardiac hypertrophy. Here, we summarize the latest research progress on epigenetics in cardiac hypertrophy involving DNA methylation, histone modification, and non-coding RNA, to help understand the mechanism of epigenetics in cardiac hypertrophy. The expression of both embryonic and functional genes can be precisely regulated by epigenetic mechanisms during cardiac hypertrophy, providing a substantial number of therapeutic targets. Thus, epigenetic treatment is expected to become a novel therapeutic strategy for cardiac hypertrophy. According to the research performed to date, epigenetic mechanisms associated with cardiac hypertrophy remain far from completely understood. Therefore, epigenetic mechanisms require further exploration to improve the prevention, diagnosis, and treatment of cardiac hypertrophy.

Association between air pollutants and development of chronic kidney disease: A systematic review and meta-analysis

BACKGROUND

The association between incident chronic kidney disease (CKD) or end-stage renal disease (ESRD) and exposure to outdoor air pollution is under debate. We aimed to examine this relationship based on a systematic review with random-effects meta-analysis.

METHODS

We screened the literature on long-term air pollution exposure assessment in the general population using an electronic search of PubMed, Medline, Embase, and Cochrane Library from inception to 20 October 2019. Observational studies investigating the association between long-term exposure to gaseous (CO, SO₂, NO₂, O₃) or particulate (PM_2.5 or PM₁₀) outdoor air pollutants and CKD, ESRD, or renal dysfunction were included, and summary risks were estimated.

RESULTS

Of 4419 identified articles, 23 met our inclusion criteria after screening and 14 were included in the meta-analysis. Pooled effect estimates had the following summary risk ratios (RRs) for CKD: 1.10 (95% confidence intervals [CI] 1.00, 1.21; derived from four studies) per 10 μg/m³ increase in PM_2.5 and 1.16 (95% CI 1.05, 1.29; derived from four studies) for PM₁₀; 1.31 (95% CI 0.86, 2.00; derived from two studies) per 10 ppm increase in CO; and 1.11 (95% CI 1.09, 1.14; derived from three studies) per 10 ppb increase in NO₂. For the pooled effect on eGFR, increases in PM₁₀ and PM_2.5 (of 10 μg/m³) were associated with eGFR decline by -0.83 (95% CI -1.54, -0.12; derived from two studies) and -4.11 (95% CI -12.64, 4.42; derived from two studies) mL/min/1.73 m², respectively.

CONCLUSIONS

Air pollution was observed to be associated with CKD and renal function decline. Although more longitudinal studies are required, we argue that air pollution is pernicious to kidney health.

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

Lung development continues from the embryonic period to adulthood. Previous epidemiological studies have noted that maternal exposure of atmospheric pollutants during the sensitive windows disturbed the lung development and increased the risk of lung diseases after birth, but the experimental evidence was insufficient. In the present study, we exposed plug-positive mice to PM_2.5 (3 mg/kg b.w.) by oropharyngeal aspiration every other day, and intended to test whether maternal PM_2.5 exposure affected prenatal lung development in the offspring. First, maternal PM_2.5 exposure decreased embryo weight and crown-rump length at E18.5 but not in earlier developmental stages (E0-E16.5). Second, maternal PM_2.5 exposure did not prevent lung-bud and tracheal specification, and did not cause abnormalities in branching morphogenesis, distal lung epithelium, and mesenchyme differentiation in earlier stages of lung development (E0-E16.5). However, the exposure significantly disturbed the distal lung epithelium and mesenchyme differentiation of lung, led to reduced intact rings of trachea, and suppressed the expression of lung development-related genes (Nkx2.1, Tbx4, Tbx5, and Sox9) at E18.5. Finally, we found that the exposure not only increased PM_2.5-bound metal content (Pb and Cu) but also caused inflammatory response in the placenta, which transmitted from the mother to the fetus and contributed to the developmental abnormalities.