The involvement of Nox4 in fine particulate matter exposure-induced cardiac injury in mice

Particulate Matter-Induced Neurotoxicity: Unveiling the Role of NOX4-Mediated ROS Production and Mitochondrial Dysfunction in Neuronal Apoptosis

Urban air pollution, a significant environmental hazard, is linked to adverse health outcomes and increased mortality across various diseases. This study investigates the neurotoxic effects of particulate matter (PM), specifically PM2.5 and PM10, by examining their role in inducing oxidative stress and subsequent neuronal cell death. We highlight the novel finding that PM increases mitochondrial ROS production via stimulating NOX4 activity, not through its expression level in Neuro-2A cells. Additionally, PMs provoke ROS production via increasing the expression and activity of NOX2 in SH-SY5Y human neuroblastoma cells, implying differential regulation of NOX proteins. This increase in mitochondrial ROS triggers the opening of the mitochondrial permeability transition pore (mPTP), leading to apoptosis through key mediators, including caspase3, BAX, and Bcl2. Notably, the voltage-dependent anion-selective channel 1 (VDAC1) increases at 1 µg/mL of PM2.5, while PM10 triggers an increase from 10 µg/mL. At the same concentration (100 µg/mL), PM2.5 causes 1.4 times higher ROS production and 2.4 times higher NOX4 activity than PM10. The cytotoxic effects induced by PMs were alleviated by NOX inhibitors GKT137831 and Apocynin. In SH-SY5Y cells, both PM types increase ROS and NOX2 levels, leading to cell death, which Apocynin rescues. Variability in NADPH oxidase sources underscores the complexity of PM-induced neurotoxicity. Our findings highlight NOX4-driven ROS and mitochondrial dysfunction, suggesting a potential therapeutic approach for mitigating PM-induced neurotoxicity.

Effects of fine particulate matter on bone marrow-conserved hematopoietic and mesenchymal stem cells: a systematic review

The harmful effects of fine particulate matter ≤2.5 µm in size (PM2.5) on human health have received considerable attention. However, while the impact of PM2.5 on the respiratory and cardiovascular systems has been well studied, less is known about the effects on stem cells in the bone marrow (BM). With an emphasis on the invasive characteristics of PM2.5, this review examines the current knowledge of the health effects of PM2.5 exposure on BM-residing stem cells. Recent studies have shown that PM2.5 enters the circulation and then travels to distant organs, including the BM, to induce oxidative stress, systemic inflammation and epigenetic changes, resulting in the reduction of BM-residing stem cell survival and function. Understanding the broader health effects of air pollution thus requires an understanding of the invasive characteristics of PM2.5 and its direct influence on stem cells in the BM. As noted in this review, further studies are needed to elucidate the underlying processes by which PM2.5 disturbs the BM microenvironment and inhibits stem cell functionality. Strategies to prevent or ameliorate the negative effects of PM2.5 exposure on BM-residing stem cells and to maintain the regenerative capacity of those cells must also be investigated. By focusing on the complex relationship between PM2.5 and BM-resident stem cells, this review highlights the importance of specific measures directed at safeguarding human health in the face of rising air pollution.

Vitamin B ameliorates PM2.5-induced kidney damage by reducing endoplasmic reticulum stress and oxidative stress in pregnant mice and HK-2

As an air pollutant, particulate matters 2.5 (PM_2.5) poses a severe risk to kidney and the mechanism involves oxidative stress and endoplasmic reticulum (ER) stress. As an essential nutrient for human health, Vitamin B performs anti-inflammatory and antioxidant functions. In order to study the effect of Vitamin B on PM_2.5-induced kidney damage during pregnancy, the pregnant mice were divided into the four experimental groups randomly: control group, model group, treatment group and VB group. PM_2.5 was sprayed on the trachea of pregnant mice once each three days for six times from pregnancy until delivery. The model group was given 30μL PM_2.5 suspension of 3.456μg/μL and 10mL/(kg·d) PBS. The treatment group was given 30μL PM_2.5 suspension of 3.456μg/μL and 10mL/(kg·d) Vitamin B. The VB group was given 10mL/(kg·d) Vitamin B and the control group was given the same dose of PBS. Vitamin B was composed of Vitamin B6, Vitamin B12 and folic acid, with final concentrations are 1.14, 0.02 and 0.06mg/mL, respectively. The results showed Vitamin B ameliorated PM_2.5-induced kidney damage such as improving histopathological change, decreasing expressions of Bip and Chop, increasing expressions of Nrf2, HO-1 and Nqo1. In addition, HK-2 cells were used for cell experiments and were divided into the four groups, in which the dosage of PM_2.5 was 75μg/mL for 24h and Vitamin B was 5μL/100μL. The results showed Vitamin B ameliorated PM_2.5-induced HK-2 damage, such as decreasing expressions of Bip, Chop, P47^phox and ROS, increasing expressions of Nrf2, HO-1, Nqo1 and NO. Our findings showed Vitamin B ameliorated PM_2.5-induced kidney damage by reducing ER stress and oxidative stress in pregnant mice and in HK-2.

Cardiovascular adaptations to particle inhalation exposure: molecular mechanisms of the toxicology

Ambient air, occupational settings, and the use and distribution of consumer products all serve as conduits for toxicant exposure through inhalation. While the pulmonary system remains a primary target following inhalation exposure, cardiovascular implications are exceptionally culpable for increased morbidity and mortality. The epidemiological evidence for cardiovascular dysfunction resulting from acute or chronic inhalation exposure to particulate matter has been well documented, but the mechanisms driving the resulting disturbances remain elusive. In the current review, we aim to summarize the cellular and molecular mechanisms that are directly linked to cardiovascular health following exposure to a variety of inhaled toxicants. The purpose of this review is to provide a comprehensive overview of the biochemical changes in the cardiovascular system following particle inhalation exposure and to highlight potential biomarkers that exist across multiple exposure paradigms. We attempt to integrate these molecular signatures in an effort to provide direction for future investigations. This review also characterizes how molecular responses are modified in at-risk populations, specifically the impact of environmental exposure during critical windows of development. Maternal exposure to particulate matter during gestation can lead to fetal epigenetic reprogramming, resulting in long-term deficits to the cardiovascular system. In both direct and indirect (gestational) exposures, connecting the biochemical mechanisms with functional deficits outlines pathways that can be targeted for future therapeutic intervention. Ultimately, future investigations integrating "omics"-based approaches will better elucidate the mechanisms that are altered by xenobiotic inhalation exposure, identify biomarkers, and guide in clinical decision making.

NLRP3 inflammasome activation is associated with PM2.5 -induced cardiac functional and pathological injury in mice

Growing evidences indicate that inflammation induced by PM_2.5 exposure has been considered as a major driving force for the development of cardiovascular diseases. However, the mechanisms underlying PM_2.5 -induced cardiac injury remain unclear. This study aims to investigate the role of NLRP3 inflammasome in PM_2.5 -induced cardiac functional and pathological injury in mice. In this study, BALB/c mice were intratracheally instilled with PM_2.5 suspension (4.0 mg/kg BW) for 5 days to set up a cardiac injury model, which was evaluated by electrocardiogram monitoring, HE and Masson staining. Then, the effects of PM_2.5 on the expression of α-SMA, NLRP3, IL-1β, and IL-18 proteins and the activation of caspase-1 and IL-1β were investigated. The results showed that PM_2.5 exposure induced characteristic abnormal ECG changes such as the abnormality of heart rhythm, tachycardia, and T-wave reduction. Inflammatory cell infiltration and fibrosis were observed in the heart tissues of PM_2.5 -exposed mice. Meanwhile, PM_2.5 exposure increased the expression of α-SMA. And, NLRP3 activation-associated proteins of NLRP3, IL-1β, IL-18, Cleaved caspase-1 p10, and Cleaved IL-1β were upregulated in heart tissue of PM_2.5 -induced mice. In summary, PM_2.5 exposure could induce cardiac functional and pathological injury, which may be associated with the activation of NLRP3 inflammasome.

Activation of the mammalian target of rapamycin signaling pathway underlies a novel inhibitory role of ring finger protein 182 in ventricular remodeling after myocardial ischemia-reperfusion injury

Myocardial ischemia-reperfusion injury (MIRI) is a major cause of cardiovascular disease, leading to mortality and disability associated with coronary occlusion worldwide. A correlation of mammalian target of rapamycin (mTOR)/nuclear factor-kappa B (NF-κB) signaling pathway has been observed with brain damage resulting from myocardial ischemia. Therefore, by establishing MIRI rat model, this study aimed to explore whether ring finger protein 182 (RNF182) regulates the mTOR signaling pathway affecting MIRI. Initially, MIRI rat model was successfully established, followed by either treatment of shRNF182 or phosphoesterase (PITE) (inhibitor of the mTOR signaling pathway). Then, the serum levels of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and malondialdehyde (MDA), left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), left ventricular systolic pressure (LVSP), and left ventricular end-diastolic pressure (LVEDP) were determined, followed by detection of myocardial infarct sizes and myocardial cell apoptosis. Moreover, the levels of related genes/proteins were determined to further determine the mechanisms of RNF182 in MIRI. First, RNF182 was upregulated in MIRI. Another key observation of this study was that rats with shRNF182 presented with downregulated SOD, GSH-Px, and MDA in serum, accompanied by decreased levels of LVEF, LVFS, LVSP, and LVEDP. In addition, both reduced myocardial infarct sizes and apoptosis of myocardial cells were observed after silencing RNF182. Furthermore, silencing of the RNF182 was observed to downregulate Bcl 2-associated X and cysteine proteinase 3 but upregulate mTOR, ribosome protein subunit 6 kinase 1, eukaryotic elongation factor 2, and B-cell lymphoma-2. Importantly, the effects of RNF182 silencing were reversed after PITE treatment. In conclusion, our study demonstrates that RNF182 silencing can prevent ventricular remodeling in rats after MIRI by activating the mTOR signaling pathway.