Causation by Diesel Exhaust Particles of Endothelial Dysfunctions in Cytotoxicity, Pro-inflammation, Permeability, and Apoptosis Induced by ROS Generation

Targeting NF-κB in Hepatic Ischemia-Reperfusion Alleviation: from Signaling Networks to Therapeutic Targeting

Hepatic ischemia-reperfusion injury (HIRI) is a major complication of liver trauma, resection, and transplantation that can lead to liver dysfunction and failure. Scholars have proposed a variety of liver protection methods aimed at reducing ischemia-reperfusion damage, but there is still a lack of effective treatment methods, which urgently needs to find new effective treatment methods for patients. Many studies have reported that signaling pathway plays a key role in HIRI pathological process and liver function recovery mechanism, among which nuclear transfer factor-κB (NF-κB) signaling pathway is one of the signal transduction closely related to disease. NF-κB pathway is closely related to HIRI pathologic process, and inhibition of this pathway can delay oxidative stress, inflammatory response, cell death, and mitochondrial dysfunction. In addition, NF-κB can also interact with PI3K/Akt, MAPK, and Nrf2 signaling pathways to participate in HIRI regulation. Based on the role of NF-κB pathway in HIRI, it may be a potential target pathway for HIRI. This review emphasizes the role of inhibiting the NF-κB signaling pathway in oxidative stress, inflammatory response, cell death, and mitochondrial dysfunction in HIRI, as well as the effects of related drugs or inhibitors targeting NF-κB on HIRI. The objective of this review is to elucidate the role and mechanism of NF-κB pathway in HIRI, emphasize the important role of NF-κB pathway in the prevention and treatment of HIRI, and provide a theoretical basis for the target NF-κB pathway as a therapy for HIRI.

An Injectable Black Phosphorus Hydrogel for Rapid Tooth Extraction Socket Healing

The excess production of reactive oxygen species (ROS) will delay tooth extraction socket (TES) healing. In this study, we developed an injectable thermosensitive hydrogel (NBP@BP@CS) used to treat TES healing. The hydrogel formulation incorporated black phosphorus (BP) nanoflakes, recognized for their accelerated alveolar bone regeneration and ROS-scavenging properties, and dl-3-n-butylphthalide (NBP), a vasodilator aimed at enhancing angiogenesis. In vivo investigations strongly demonstrated that NBP@BP@CS improved TES healing due to antioxidation and promotion of alveolar bone regeneration by BP nanoflakes. The sustained release of NBP from the hydrogel promoted neovascularization and vascular remodeling. Our results demonstrated that the designed thermosensitive hydrogel provided great opportunity not only for ROS elimination but also for the promotion of osteogenesis and angiogenesis, reflecting the "three birds with one stone" concept, and has tremendous potential for rapid TES healing.

The stress-responsive cytotoxic effect of diesel exhaust particles on lymphatic endothelial cells

Diesel exhaust particles (DEPs) are very small (typically < 0.2 μm) fragments that have become major air pollutants. DEPs are comprised of a carbonaceous core surrounded by organic compounds such as polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs. Inhaled DEPs reach the deepest sites in the respiratory system where they could induce respiratory/cardiovascular dysfunction. Additionally, a previous study has revealed that a portion of inhaled DEPs often activate immune cells and subsequently induce somatic inflammation. Moreover, DEPs are known to localize in lymph nodes. Therefore, in this study we explored the effect of DEPs on the lymphatic endothelial cells (LECs) that are a constituent of the walls of lymph nodes. DEP exposure induced cell death in a reactive oxygen species (ROS)-dependent manner. Following exposure to DEPs, next-generation sequence (NGS) analysis identified an upregulation of the integrated stress response (ISR) pathway and cell death cascades. Both the soluble and insoluble components of DEPs generated intracellular ROS. Three-dimensional Raman imaging revealed that DEPs are taken up by LECs, which suggests internalized DEP cores produce ROS, as well as soluble DEP components. However, significant cell death pathways such as apoptosis, necroptosis, ferroptosis, pyroptosis, and parthanatos seem unlikely to be involved in DEP-induced cell death in LECs. This study clarifies how DEPs invading the body might affect the lymphatic system through the induction of cell death in LECs.

Lipid Dysregulation Induced by Gasoline and Diesel Exhaust Exposure and the Interaction with Age

Limited knowledge exists regarding gasoline and diesel exhaust effects on lipid metabolism. This study collected gasoline and diesel exhaust under actual driving conditions and conducted inhalation exposure on male young and middle-aged C57BL/6J mice for 4 h/day for 5 days to simulate commuting exposure intensity. Additionally, PM2.5 from actual roadways, representing gasoline and diesel vehicles, was generated for exposure to human umbilical vein endothelial cells (HUVECs) and normal liver cells (LO2) for 24, 48, and 72 h to further investigate exhaust particle toxicity. Results showed that diesel exhaust reduced total cholesterol and low-density lipoprotein cholesterol levels in young mice, indicating disrupted lipid metabolism. Aspartate aminotransferase and alanine aminotransferase levels increased by 53.7% and 21.7%, respectively, suggesting potential liver injury. Diesel exhaust exposure decreased superoxide dismutase and increased glutathione peroxidase levels. Cell viability decreased, and reactive oxygen species levels increased in HUVECs and LO2 following exposure to exhaust particles, with dose- and time-dependent effects. Diesel exhaust particles exhibited more severe inhibition of cell proliferation and oxidative damage compared to gasoline exhaust particles. These findings provide novel evidence of the risk of disrupted lipid metabolism due to gasoline and diesel exhaust, emphasizing the toxicity of diesel exhaust.

Evaluating the effect of acute diesel exhaust particle exposure on P-glycoprotein efflux transporter in the blood-brain barrier co-cultured with microglia

A growing public health concern, chronic Diesel Exhaust Particle (DEP) exposure is a heavy risk factor for the development of neurodegenerative diseases like Alzheimer's (AD). Considered the brain's first line of defense, the Blood-Brain Barrier (BBB) and perivascular microglia work in tandem to protect the brain from circulating neurotoxic molecules like DEP. Importantly, there is a strong association between AD and BBB dysfunction, particularly in the Aβ transporter and multidrug resistant pump, P-glycoprotein (P-gp). However, the response of this efflux transporter is not well understood in the context of environmental exposures, such as to DEP. Moreover, microglia are seldom included in in vitro BBB models, despite their significance in neurovascular health and disease. Therefore, the goal of this study was to evaluate the effect of acute (24 hr.) DEP exposure (2000 μg/ml) on P-gp expression and function, paracellular permeability, and inflammation profiles of the human in vitro BBB model (hCMEC/D3) with and without microglia (hMC3). Our results suggested that DEP exposure can decrease both the expression and function of P-gp in the BBB, and corroborated that DEP exposure impairs BBB integrity (i.e. increased permeability), a response that was significantly worsened by the influence of microglia in co-culture. Interestingly, DEP exposure seemed to produce atypical inflammation profiles and an unexpected general downregulation in inflammatory markers in both the monoculture and co-culture, which differentially expressed IL-1β and GM-CSF. Interestingly, the microglia in co-culture did not appear to influence the response of the BBB, save in the permeability assay, where it worsened the BBB's response. Overall, our study is important because it is the first (to our knowledge) to investigate the effect of acute DEP exposure on P-gp in the in vitro human BBB, while also investigating the influence of microglia on the BBB's responses to this environmental chemical.

The Road to Malignant Cell Transformation after Particulate Matter Exposure: From Oxidative Stress to Genotoxicity

In cells, oxidative stress is an imbalance between the production/accumulation of oxidants and the ability of the antioxidant system to detoxify these reactive products. Reactive oxygen species (ROS), cause multiple cellular damages through their interaction with biomolecules such as lipids, proteins, and DNA. Genotoxic damage caused by oxidative stress has become relevant since it can lead to mutation and play a central role in malignant transformation. The evidence describes chronic oxidative stress as an important factor implicated in all stages of the multistep carcinogenic process: initiation, promotion, and progression. In recent years, ambient air pollution by particulate matter (PM) has been cataloged as a cancer risk factor, increasing the incidence of different types of tumors. Epidemiological and toxicological evidence shows how PM-induced oxidative stress could mediate multiple events oriented to carcinogenesis, such as proliferative signaling, evasion of growth suppressors, resistance to cell death, induction of angiogenesis, and activation of invasion/metastasis pathways. In this review, we summarize the findings regarding the involvement of oxidative and genotoxic mechanisms generated by PM in malignant cell transformation. We also discuss the importance of new approaches oriented to studying the development of tumors associated with PM with more accuracy, pursuing the goal of weighing the impact of oxidative stress and genotoxicity as one of the main mechanisms associated with its carcinogenic potential.

Effects of Flavonoid Supplementation on Nanomaterial-Induced Toxicity: A Meta-Analysis of Preclinical Animal Studies

Background

Nanomaterials, widely applied in various fields, are reported to have toxic effects on human beings; thus, preventive or therapeutic measures are urgently needed. Given the anti-inflammatory and antioxidant activities, supplementation with flavonoids that are abundant in the human diet has been suggested as a potential strategy to protect against nanomaterial-induced toxicities. However, the beneficial effects of flavonoids remain inconclusive. In the present study, we performed a meta-analysis to comprehensively explore the roles and mechanisms of flavonoids for animals intoxicated with nanomaterials.

Methods

A systematic literature search in PubMed, EMBASE, and Cochrane Library databases was performed up to April 2022. STATA 15.0 software was used for meta-analyses.

Results

A total of 26 studies were identified. The results showed that flavonoid supplementation could significantly increase the levels of antioxidative enzymes (superoxide dismutase, catalase, glutathione, glutathione peroxidase, and glutathione-S-transferase), reduce the production of oxidative agents (malonaldehyde) and pro-inflammatory mediators (tumor necrosis factor-α, interleukin-6, IL-1β, C-reactive protein, immunoglobulin G, nitric oxide, vascular endothelial growth factor, and myeloperoxidase), and alleviate cell apoptosis (manifested by decreases in the mRNA expression levels of pro-apoptotic factors, such as caspase-3, Fas cell surface death receptor, and Bax, and increases in the mRNA expression levels of Bcl2), DNA damage (reductions in tail length and tail DNA%), and nanomaterial-induced injuries of the liver (reduced alanine aminotransferase and aspartate aminotransferase activities), kidney (reduced urea, blood urea nitrogen, creatinine, and uric acid concentration), testis (increased testosterone, sperm motility, 17β-hydroxysteroid dehydrogenase type, and reduced sperm abnormalities), and brain (enhanced acetylcholinesterase activities). Most of the results were not changed by subgroup analyses.

Conclusion

Our findings suggest that appropriate supplementation of flavonoids may be effective to prevent the occupational detriments resulting from nanomaterial exposure.

The Contribution of Gut Microbiota and Endothelial Dysfunction in the Development of Arterial Hypertension in Animal Models and in Humans

The maintenance of the physiological values of blood pressure is closely related to unchangeable factors (genetic predisposition or pathological alterations) but also to modifiable factors (dietary fat and salt, sedentary lifestyle, overweight, inappropriate combinations of drugs, alcohol abuse, smoking and use of psychogenic substances). Hypertension is usually characterized by the presence of a chronic increase in systemic blood pressure above the threshold value and is an important risk factor for cardiovascular disease, including myocardial infarction, stroke, micro- and macro-vascular diseases. Hypertension is closely related to functional changes in the endothelium, such as an altered production of vasoconstrictive and vasodilator substances, which lead to an increase in vascular resistance. These alterations make the endothelial tissue unresponsive to autocrine and paracrine stimuli, initially determining an adaptive response, which over time lead to an increase in risk or disease. The gut microbiota is composed of a highly diverse bacterial population of approximately 10¹⁴ bacteria. A balanced intestinal microbiota preserves the digestive and absorbent functions of the intestine, protecting from pathogens and toxic metabolites in the circulation and reducing the onset of various diseases. The gut microbiota has been shown to produce unique metabolites potentially important in the generation of hypertension and endothelial dysfunction. This review highlights the close connection between hypertension, endothelial dysfunction and gut microbiota.

LSEA Evaluation of Lipid Mediators of Inflammation in Lung and Cortex of Mice Exposed to Diesel Air Pollution

Airborne ultrafine particle (UFP) exposure is a great concern as they have been correlated to increased cardiovascular mortality, neurodegenerative diseases and morbidity in occupational and environmental settings. The ultrafine components of diesel exhaust particles (DEPs) represent about 25% of the emission mass; these particles have a great surface area and consequently high capacity to adsorb toxic molecules, then transported throughout the body. Previous in-vivo studies indicated that DEP exposure increases pro- and antioxidant protein levels and activates inflammatory response both in respiratory and cardiovascular systems. In cells, DEPs can cause additional reactive oxygen species (ROS) production, which attacks surrounding molecules, such as lipids. The cell membrane provides lipid mediators (LMs) that modulate cell-cell communication, inflammation, and resolution processes, suggesting the importance of understanding lipid modifications induced by DEPs. In this study, with a lipidomic approach, we evaluated in the mouse lung and cortex how DEP acute and subacute treatments impact polyunsaturated fatty acid-derived LMs. To analyze the data, we designed an ad hoc bioinformatic pipeline to evaluate the functional enrichment of lipid sets belonging to the specific biological processes (Lipid Set Enrichment Analysis-LSEA). Moreover, the data obtained correlate tissue LMs and proteins associated with inflammatory process (COX-2, MPO), oxidative stress (HO-1, iNOS, and Hsp70), involved in the activation of many xenobiotics as well as PAH metabolism (Cyp1B1), suggesting a crucial role of lipids in the process of DEP-induced tissue damage.

Blockade of caspase cascade overcomes malaria-associated acute respiratory distress syndrome in mice

Malaria is an enormous burden on global health that caused 409,000 deaths in 2019. Severe malaria can manifest in the lungs, an illness known as acute respiratory distress syndrome (ARDS). Not much is known about the development of malaria-associated ARDS (MA-ARDS), especially regarding cell death in the lungs. We had previously established a murine model that mimics various human ARDS aspects, such as pulmonary edema, hemorrhages, pleural effusion, and hypoxemia, using DBA/2 mice infected with Plasmodium berghei ANKA. Here, we explored the mechanisms and the involvement of apoptosis in this syndrome. We found that apoptosis contributes to the pathogenesis of MA-ARDS, primarily as facilitators of the alveolar-capillary barrier breakdown. The protection of pulmonary endothelium by inhibiting caspase activation could be a promising therapeutic strategy to prevent the pathogenicity of MA-ARDS. Therefore, intervention in the programmed death cell mechanism could help patients not to develop severe malaria.

Effect of Aerobic Exercise on Oxidative Stress and Inflammatory Response During Particulate Matter Exposure in Mouse Lungs

Regular exercise provides several health benefits that can improve the cardiovascular and musculoskeletal systems, but clear evidence on the effect of exercise-induced hyperventilation in particulate matter (PM) exposure is still lacking. This study aimed to investigate the effects of exercise in PM exposure on reactive oxygen species (ROS) generation, inflammatory response, and mitochondrial integrity in human lung epithelial cells (A549), as well as in mouse lung tissue. In in vitro experiments, PM treatment was shown to significantly increased ROS production, and reduced cell viability and mitochondrial function in A549 cells. The mice were divided into four groups for an in vivo exercise experiment: control (CON), PM inhalation (PI), PM inhalation during exercise (PIE), and exercise (EX) groups. The PI and PIE groups were exposed to 100 μg/m³ of PM for 1 h per day for a week. The PIE and EX groups performed treadmill exercises every day for 1 h at 20 m/min for a week. The levels of pro-inflammatory markers (IL-6 and TNF-α) were significantly higher in the PI group than in the CON group (P < 0.001 and P < 0.01, respectively). The carbonyl protein level was decreased in EX vs. PI (P < 0.001). Mitochondrial fission (Drp1) content was significantly decreased in the EX vs. CON group (P < 0.01), but anti-mitochondrial fission (P-Drp1 Ser637) was increased in the EX vs. PI group (P < 0.05). Mitochondrial autophagy (mitophagy), which is an assessment of mitochondrial integrity, was markedly increased in PI vs. CON (P < 0.001), but the level was reversed in PIE (P < 0.05). Lung fibrosis was increased in PI vs. CON group (P < 0.001), however, the cells were rescued in the PIE (P < 0.001). The number of apoptotic cells was remarkably increased in the PI vs. CON group (P < 0.001), whereas the level was decreased in the PIE (P < 0.001). Taken together, these results showed that short-term exposure to PM triggers oxidative stress, pro-inflammatory responses, and apoptosis in the lungs, but the PM-induced adverse effects on the lung tissue are not exacerbated by exercise-induced PM hyperventilation but rather has a protective effect.

3-Bromofluoranthene-induced cardiotoxicity of zebrafish and apoptosis in the vascular endothelial cells via intrinsic and extrinsic caspase-dependent pathways

Fluoranthene, a high-molecular-weight polycyclic aromatic hydrocarbon (PAH), is widely present in air pollutants, including fine inhalable particulate matter. 3-Bromofluoranthene (3-BrFlu), which is a brominated fluoranthene and halogenated PAH, is generated from waste combustion, metallurgical processes, cement production, e-waste dismantling, and photoreaction. Vascular endothelial cells have key functions in the homeostasis and the development of the cardiovascular system. The zebrafish model has been widely employed to study cardiotoxicity and embryotoxicity. However, no evidence has indicated that 3-BrFlu induces cytotoxicity in vascular endothelial cells, or cardiotoxicity and embryotoxicity in zebrafish. In this study, 3-BrFlu induced concentration-dependent changes in embryo- and cardiotoxicity. Cytotoxicity was also induced by 3-BrFlu in a concentration-dependent manner through apoptosis and necrosis in vascular endothelial cells, SVEC4-10 cells. The activities of caspase-3, -8, and -9 were induced by 3-BrFlu via an intrinsic pathway constituting Bcl-2 downregulation, Bad upregulation, and mitochondrial dysfunction; the extrinsic pathway included the expression of death receptors, including tumour necrosis factor α and Fas receptors. These results indicated that 3-BrFlu caused cardio- and embryotoxicity in zebrafish through vascular endothelial cells cytotoxicity resulting from caspase-dependent apoptosis through intrinsic and extrinsic pathways.

Epigenetic Regulation of Endothelial Dysfunction and Inflammation in Pulmonary Arterial Hypertension

Once perceived as a disorder treated by vasodilation, pulmonary artery hypertension (PAH) has emerged as a pulmonary vascular disease with severe endothelial cell dysfunction. In the absence of a cure, many studies seek to understand the detailed mechanisms of EC regulation to potentially create more therapeutic options for PAH. Endothelial dysfunction is characterized by complex phenotypic changes including unchecked proliferation, apoptosis-resistance, enhanced inflammatory signaling and metabolic reprogramming. Recent studies have highlighted the role of epigenetic modifications leading to pro-inflammatory response pathways, endothelial dysfunction, and the progression of PAH. This review summarizes the existing literature on epigenetic mechanisms such as DNA methylation, histone modifications, and non-coding RNAs, which can lead to aberrant endothelial function. Our goal is to develop a conceptual framework for immune dysregulation and epigenetic changes in endothelial cells in the context of PAH. These studies as well as others may lead to advances in therapeutics to treat this devastating disease.

Early Warning Systems for COVID-19 Infections Based on Low-Cost Indoor Air-Quality Sensors and LPWANs

During the last two years, the COVID-19 pandemic continues to wreak havoc in many areas of the world, as the infection spreads through person-to-person contact. Transmission and prognosis, once infected, are potentially influenced by many factors, including indoor air pollution. Particulate Matter (PM) is a complex mixture of solid and/or liquid particles suspended in the air that can vary in size, shape, and composition and recent scientific work correlate this index with a considerable risk of COVID-19 infections. Early Warning Systems (EWS) and the Internet of Things (IoT) have given rise to the development of Low Power Wide Area Networks (LPWAN) based on sensors, which measure PM levels and monitor In-door Air pollution Quality (IAQ) in real-time. This article proposes an open-source platform architecture and presents the development of a Long Range (LoRa) based sensor network for IAQ and PM measurement. A few air quality sensors were tested, a network platform was implemented after simulating setup topologies, emphasizing feasible low-cost open platform architecture.

Sodium Glucose Co-Transporter 2 Inhibitors Ameliorate Endothelium Barrier Dysfunction Induced by Cyclic Stretch through Inhibition of Reactive Oxygen Species

SGLT-2i's exert direct anti-inflammatory and anti-oxidative effects on resting endothelial cells. However, endothelial cells are constantly exposed to mechanical forces such as cyclic stretch. Enhanced stretch increases the production of reactive oxygen species (ROS) and thereby impairs endothelial barrier function. We hypothesized that the SGLT-2i's empagliflozin (EMPA), dapagliflozin (DAPA) and canagliflozin (CANA) exert an anti-oxidative effect and alleviate cyclic stretch-induced endothelial permeability in human coronary artery endothelial cells (HCAECs). HCAECs were pre-incubated with one of the SGLT-2i's (1 µM EMPA, 1 µM DAPA and 3 µM CANA) for 2 h, followed by 10% stretch for 24 h. HCAECs exposed to 5% stretch were considered as control. Involvement of ROS was measured using N-acetyl-l-cysteine (NAC). The sodium-hydrogen exchanger 1 (NHE1) and NADPH oxidases (NOXs) were inhibited by cariporide, or GKT136901, respectively. Cell permeability and ROS were investigated by fluorescence intensity imaging. Cell permeability and ROS production were increased by 10% stretch; EMPA, DAPA and CANA decreased this effect significantly. Cariporide and GKT136901 inhibited stretch-induced ROS production but neither of them further reduced ROS production when combined with EMPA. SGLT-2i's improve the barrier dysfunction of HCAECs under enhanced stretch and this effect might be mediated through scavenging of ROS. Anti-oxidative effect of SGLT-2i's might be partially mediated by inhibition of NHE1 and NOXs.

Phenolic profile of jujube fruit subjected to gut microbiota fermentation and its antioxidant potential against ethyl carbamate-induced oxidative damage

OBJECTIVES

To evaluate the composition of bioactive substances and the antioxidant effects of jujube fruit under gut microbiota fermentation (GMF), and the inhibitory effect on cytotoxicity caused by ethyl carbamate (EC).

METHODS

Changes in the contents of flavonoids, polyphenols, total sugars, and reducing sugars of jujube fruit after GMF (0, 2, 6, 12, 24, and 48 h) were determined. The oxidation resistance of fermented jujube fruits (from 0 to 48 h fermentation) was evaluated using in vitro 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) and ferric reducing antioxidant power (FRAP) assays. Inhibitory effects of 48 h-fermented jujube fruit at various concentrations (0.25, 0.50, 1.00, and 2.00 mg/mL) on EC-treated toxicity and DNA damage of Caco-2 cells were estimated using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) and nuclear staining assays, respectively. Effects of different concentrations of jujube fruit on EC-treated Caco-2 cells' intracellular reactive oxygen species (ROS), glutathione (GSH) levels, and mitochondrial membrane potential (MMP) were also evaluated.

RESULTS

Jujube fruit has rich bioactive components after GMF and shows strong antioxidant capacity. Fermented jujube fruit can inhibit the cytotoxicity and DNA damage of Caco-2 cells caused by EC and reduce intracellular ROS generation, as well as restoring GSH and MMP.

CONCLUSIONS

Fermented jujube fruit extracts produced by GMF still contain biologically active substances which retain biological activity and antioxidation capabilities.

Micro- and Nanosized Substances Cause Different Autophagy-Related Responses

With rapid industrialization, humans produce an increasing number of products. The composition of these products is usually decomposed. However, some substances are not easily broken down and gradually become environmental pollutants. In addition, these substances may cause bioaccumulation, since the substances can be fragmented into micro- and nanoparticles. These particles or their interactions with other toxic matter circulate in humans via the food chain or air. Whether these micro- and nanoparticles interfere with extracellular vesicles (EVs) due to their similar sizes is unclear. Micro- and nanoparticles (MSs and NSs) induce several cell responses and are engulfed by cells depending on their size, for example, particulate matter with a diameter ≤2.5 μm (PM2.5). Autophagy is a mechanism by which pathogens are destroyed in cells. Some artificial materials are not easily decomposed in organisms. How do these cells or tissues respond? In addition, autophagy operates through two pathways (increasing cell death or cell survival) in tumorigenesis. Many MSs and NSs have been found that induce autophagy in various cells and tissues. As a result, this review focuses on how these particles interfere with cells and tissues. Here, we review MSs, NSs, and PM2.5, which result in different autophagy-related responses in various tissues or cells.

Evaluating the endothelial-microglial interaction and comprehensive inflammatory marker profiles under acute exposure to ultrafine diesel exhaust particles in vitro

Exposure to combustion-derived particulate matter (PM) such as diesel exhaust particles (DEP) is a public health concern because people in urban areas are continuously exposed, and once inhaled, fine and ultrafine DEP may reach the brain. The blood-brain barrier (BBB) endothelial cells (EC) and the perivascular microglia protect the brain from circulating pathogens and neurotoxic molecules like DEP. While the BBB-microglial interaction is critical for maintaining homeostasis, no study has previously evaluated the endothelial-microglial interaction nor comprehensively characterized these cells' inflammatory marker profiles under ultrafine DEP exposures in vitro. Therefore, the goal of this study was to investigate the in vitro rat EC-microglial co-culture under acute (24 h.) exposure to ultrafine DEP (0.002-20 μg/mL), by evaluating key mechanisms associated with PM toxicity: lactate dehydrogenase (LDH) leakage, reactive oxygen species (ROS) generation, cell metabolic activity (CMA) changes, and production of 27 inflammatory markers. These parameters were also evaluated in rat microglial and endothelial monocultures to determine whether the EC-microglial co-culture responded differently than the cerebrovasculature and microglia alone. While results indicated that ultrafine DEP exposure caused concentration-dependent increases in LDH leakage and ROS production in all groups, as expected, exposure also caused mixed responses in CMA and atypical cytokine/chemokine profiles in all groups, which was not expected. The inflammation assay results further suggested that the microglia were not classically activated under this exposure scenario, despite previous in vitro studies showing microglial activation (priming) at similar concentrations of ultrafine DEP. Additionally, compared to the cerebrovasculature alone, the EC-microglia interaction in the co-culture did not appear to cause changes in any parameter save in pro-inflammatory marker production, where the interaction appeared to cause an overall downregulation in cytokine/chemokine levels after ultrafine DEP exposure. Finally, to our knowledge, this is the first study to evaluate the influence of microglia on the BBB's ultrafine DEP-induced cytotoxic and inflammatory responses, which are heavily implicated in the pathogenesis of PM-related cerebrovascular dysfunction and neurodegeneration.

Combined Toxicity of Metal Nanoparticles: Comparison of Individual and Mixture Particles Effect

Toxicity of metal nanoparticles (NPs) are closely associated with increasing intracellular reactive oxygen species (ROS) and the levels of pro-inflammatory mediators. However, NP interactions and surface complexation reactions alter the original toxicity of individual NPs. To date, toxicity studies on NPs have mostly been focused on individual NPs instead of the combination of several species. It is expected that the amount of industrial and highway-acquired NPs released into the environment will further increase in the near future. This raises the possibility that various types of NPs could be found in the same medium, thereby, the adverse effects of each NP either could be potentiated, inhibited or remain unaffected by the presence of the other NPs. After uptake of NPs into the human body from various routes, protein kinases pathways mediate their toxicities. In this context, family of mitogen-activated protein kinases (MAPKs) is mostly efficient. Despite each NP activates almost the same metabolic pathways, the toxicity induced by a single type of NP is different than the case of co-exposure to the combined NPs. The scantiness of toxicological data on NPs combinations displays difficulties to determine, if there is any risk associated with exposure to combined nanomaterials. Currently, in addition to mathematical analysis (Response surface methodology; RSM), the quantitative-structure-activity relationship (QSAR) is used to estimate the toxicity of various metal oxide NPs based on their physicochemical properties and levels applied. In this chapter, it is discussed whether the coexistence of multiple metal NPs alter the original toxicity of individual NP. Additionally, in the part of "Toxicity of diesel emission/exhaust particles (DEP)", the known individual toxicity of metal NPs within the DEP is compared with the data regarding toxicity of total DEP mixture.

Mechanical cues protect against silica nanoparticle exposure in SH-SY5Y neuroblastoma

The increasing appearance of engineered nanomaterials in broad biomedical and industrial sectors poses an escalating health concern from unintended exposure with unknown consequences. Routine in vitro assessments of nanomaterial toxicity are a vital component to addressing these mounting health concerns; however, despite the known role of cell-cell and cell-matrix contacts in governing cell survival, these physical interactions are generally ignored. Herein, we demonstrate that exposure to amorphous silica particles destabilizes mitochondrial membrane potential, stimulates reactive oxygen species (ROS) production and promotes cytotoxicity in SH-SY5Y human neuroblastoma through mechanisms that are potently matrix dependent, with SH-SY5Y cells plated on the softest matrix displaying a near complete recovery in viability compared to dose-matched cells plated on tissue-culture plastic. Cells on the softest matrix (3 kPa) further displayed a 50% reduction in ROS production and preserved mitochondrial membrane potential. The actin cytoskeleton is mechanosensitive and closely related to ROS production. SH-SY5Y cells exposed to a 100 μg/mL dose of 50 nm silica particles displayed distinct cytoskeletal aberrations and a 70% increase in cell stiffness. Overall, this study establishes that the mechanical environment can significantly impact silica nanoparticle toxicity in SH-SY5Y cells. The mechanobiochemical mechanisms behind this regulation, which are initiated at the cell-matrix interface to adjust cytoskeletal structure and intracellular tension, demand specific attention for a comprehensive understanding of nanotoxicity.

Common Genes Involved in Autophagy, Cellular Senescence and the Inflammatory Response in AMD and Drug Discovery Identified via Biomedical Databases

Purpose

Retinal pigment epithelial cell autophagy dysfunction, cellular senescence, and the retinal inflammatory response are key pathogenic factors in age-related macular degeneration (AMD), which has been reviewed in our previously work in 2019. This study aims to identify genes collectively involved in these three biological processes and target drugs in AMD.

Methods

The pubmed2ensembl database was used to perform text mining. The GeneCodis database was applied to analyze gene ontology biological process and the KEGG pathway. The STRING database was used to analyze protein–protein interaction analysis and hub genes were identified by the Cytoscape software. The Drug Gene Interaction Database was used to perform drug–gene interactions.

Results

We identified 62 genes collectively involved in AMD, autophagy, cellular senescence, and inflammatory response, 19 biological processes including 42 genes, 11 enriched KEGG pathways including 37 genes, and 12 hub genes step by step via the above biomedical databases. Finally, five hub genes (IL-6, VEGF-A, TP53, IL-1β, and transforming growth factor [TGF]-β1) and their specific interaction modes were identified, corresponding with 24 target drugs with therapeutic potential for AMD.

Conclusions

IL-6, VEGF-A, TP53, IL-1β, and TGF-β1 are pivotal in autophagy, cellular senescence, and the inflammatory response in AMD, corresponding with 24 drugs with therapeutic potential for AMD, providing definite molecular mechanisms for further research and new possibilities for AMD treatment in the future.

Translational Relevance

IL-6, VEGF-A, TP53, IL-1β, and TGF-β1 may be new targets for AMD gene therapy and drug development.

Low molecular weight-PAHs induced inflammation in A549 cells by activating PI3K/AKT and NF-κB signaling pathways

Our previous study has demonstrated that two low molecular weight-polycyclic aromatic hydrocarbons (LMW-PAHs), phenanthrene (Phe) and fluorene (Flu), alone and as a mixture could induce oxidative damage and inflammation in A549 cells. However, the associated mechanisms have not been well discussed. The aim of this study was to further investigate the roles of PI3K/AKT and NF-κB signaling pathways in the inflammatory effects in A549 cells induced by Phe, Flu and their mixture. The results indicated that Phe, Flu and their mixture significantly activated PI3K/AKT and NF-κB signaling pathways by increasing the phosphorylation levels of PI3K, AKT, IκBα and NF-κB p65. In addition, pro-inflammatory cytokine expressions of TNF-α and IL-6 induced by the binary mixture of Phe and Flu were all alleviated by co-treatment with PI3K/AKT and NF-κB specific inhibitors (LY294002 and BAY11-7082). The results suggested that PI3K/AKT and NF-κB signaling pathways played an important role in LMW-PAHs induced inflammation in A549 cells.

Antioxidant cuttlefish collagen hydrolysate against ethyl carbamate-induced oxidative damage

Ethyl carbamate (EC) has been associated with the generation of reactive oxygen species (ROS) and depletion of glutathione (GSH), leading to a decline in cell viability. In this study, we found that the cuttlefish collagen hydrolysate (CCH) exhibited high antioxidant activity in scavenging hydroxyl radicals (IC50 = 0.697 mg mL-1), which was also effective in combating EC-induced oxidative damage in liver hepatocellular carcinoma HepG2 cells. The expression of genes related to oxidative stress response could be regulated by CCH to mitigate EC-induced oxidative stress. Pathway analysis confirmed that the protective ability of CCH could be related to ferroptosis and glutathione metabolism. Therefore, CCH could reduce the decline in cell viability by alleviating GSH depletion, and prevent EC-induced oxidative damage. Moreover, protective effect of CCH could be realized by upregulating the heme oxygenase-1 to achieve the preventation of cell sensitization. Considering these effects, CCH has potential for use in food to prevent oxidative stress.

Nrf2 Lowers the Risk of Lung Injury via Modulating the Airway Innate Immune Response Induced by Diesel Exhaust in Mice

In the present study, we investigated the role of Nrf2 in airway immune responses induced by diesel exhaust (DE) inhalation in mice. C57BL/6J Nrf2^+/+ and Nrf2^−/− mice were exposed to DE or clean air for 8 h/day and 6 days/week for 4 weeks. After DE exposure, the number of neutrophils and macrophage inflammatory protein (MIP)-2 level in bronchoalveolar lavage fluid (BALF) and interleukin (IL)-17 level in the lung tissue increased in Nrf2^−/− mice compared with Nrf2^+/+ mice; however, the lack of an increase in the level of tumor necrosis factor (TNF)-α in the lung tissue in Nrf2^+/+ mice and mild suppression of the level of TNF-α in Nrf2^−/− mice were observed; the level of granulocyte macrophage colony-stimulating factor (GM-CSF) in the lung tissue decreased in Nrf2^−/− mice than in Nrf2^+/+ mice; the number of DE particle-laden alveolar macrophages in BALF were larger in Nrf2^−/− mice than in Nrf2^+/+ mice. The results of electron microscope observations showed alveolar type II cell injury and degeneration of the lamellar body after DE exposure in Nrf2^−/− mice. Antioxidant enzyme NAD(P)H quinone dehydrogenase (NQO)1 mRNA expression level was higher in Nrf2^+/+ mice than in Nrf2^−/− mice after DE exposure. Our results suggested that Nrf2 reduces the risk of pulmonary disease via modulating the airway innate immune response caused by DE in mice.

Cellular and Molecular Mechanisms of Environmental Pollutants on Hematopoiesis

Hematopoiesis is a complex and intricate process that aims to replenish blood components in a constant fashion. It is orchestrated mostly by hematopoietic progenitor cells (hematopoietic stem cells (HSCs)) that are capable of self-renewal and differentiation. These cells can originate other cell subtypes that are responsible for maintaining vital functions, mediate innate and adaptive immune responses, provide tissues with oxygen, and control coagulation. Hematopoiesis in adults takes place in the bone marrow, which is endowed with an extensive vasculature conferring an intense flow of cells. A myriad of cell subtypes can be found in the bone marrow at different levels of activation, being also under constant action of an extensive amount of diverse chemical mediators and enzymatic systems. Bone marrow platelets, mature erythrocytes and leukocytes are delivered into the bloodstream readily available to meet body demands. Leukocytes circulate and reach different tissues, returning or not returning to the bloodstream. Senescent leukocytes, specially granulocytes, return to the bone marrow to be phagocytized by macrophages, restarting granulopoiesis. The constant high production and delivery of cells into the bloodstream, alongside the fact that blood cells can also circulate between tissues, makes the hematopoietic system a prime target for toxic agents to act upon, making the understanding of the bone marrow microenvironment vital for both toxicological sciences and risk assessment. Environmental and occupational pollutants, therapeutic molecules, drugs of abuse, and even nutritional status can directly affect progenitor cells at their differentiation and maturation stages, altering behavior and function of blood compounds and resulting in impaired immune responses, anemias, leukemias, and blood coagulation disturbances. This review aims to describe the most recently investigated molecular and cellular toxicity mechanisms of current major environmental pollutants on hematopoiesis in the bone marrow.

Synergistic and antagonistic interactions among organic and metallic components of the ambient particulate matter (PM) for the cytotoxicity measured by Chinese hamster ovary cells

Although PM_2.5 toxicity is known to be related to its chemical composition, the effect of interactions among various particles' components on the toxicity is not well explored. To understand these interactions, especially metals and organic compounds on PM_2.5 cytotoxicity, we chose several redox-active substances known to be present in the ambient particles such as metals (Cu, Fe, and Mn) and quinones [9,10-phenanthraquinone (PQ), 1,2-naphthoquinone (1,2-NQ), 1,4-naphthoquinone (1,4-NQ), and 5-hydroxy-1,4-naphthoquinone (5,H-1,4-NQ)]. Cytotoxicity was assessed through a Chinese hamster ovary (CHO) cells assay and expressed by a median lethal concentration (LC₅₀). Two methods were employed to assess the interactions. In the first method, we tested the impact of nontoxic level of a component on the LC₅₀ of other components. In the second method, we mixed two components in different concentration ratios to expose the cells and calculated a mixture toxicity index (MTI). MTI is a composite value to quantify the nature of interactions such that the interactions are considered synergistic when MTI > 1, additive when 0 < MTI ≤ 1 and antagonistic when MTI < 0. The interactions between quinones and metals were largely synergistic by both methods. To further assess the environmental relevance of these mixtures, we extracted organic compounds termed as water-soluble Humic-like substances (HULIS) from real ambient PM samples and mixed them with individual metals. A similar pattern, as observed from the interaction of quinones and metals, was found. Moreover, the interactions became more synergistic as the relative concentration of metals with respect to water-soluble HULIS was decreased in these mixtures. With environmentally relevant mass concentration ratios of organics to metals (75-7500), the interactions were strongly synergistic (MTI = 1-115). These results indicate the importance of incorporating the interaction among various PM components for estimating the net toxicity of ambient PM_2.5.

Induction of Apoptosis by Coptisine in Hep3B Hepatocellular Carcinoma Cells through Activation of the ROS-Mediated JNK Signaling Pathway

Hepatocellular carcinoma (HCC) has a high mortality rate worldwide, and treatment is very limited due to its high recurrence and low diagnosis rate, and therefore there is an increasing need to develop more effective drugs to treat HCC. Coptisine is one of the isoquinoline alkaloids, and it has various pharmacological effects. However, the evidence for the molecular mechanism of the anticancer efficacy is still insufficient. Therefore, this study investigated the antiproliferative effect of coptisine on human HCC Hep3B cells and identified the action mechanism. Our results showed that coptisine markedly increased DNA damage and apoptotic cell death, which was associated with induction of death receptor proteins. Coptisine also significantly upregulated expression of proapoptotic Bax protein, downregulated expression of anti-apoptotic Bcl-2 protein, and activated caspase-3, -8, and -9. In addition, coptisine remarkably increased the generation of reactive oxygen species (ROS), loss of mitochondrial membrane potential (MMP), and release of cytochrome c into the cytoplasm. However, N-acetylcysteine (NAC), a ROS scavenger, significantly attenuated the apoptosis-inducing effect of coptisine. It is worth noting that coptisine significantly upregulated phosphorylation of ROS-dependent c-Jun N-terminal kinase (JNK), whereas treatment with JNK inhibitor could suppress an apoptosis-related series event. Taken together, our results suggest that coptisine has an anticancer effect in Hep3B cells through ROS-mediated activation of the JNK signaling pathway.

Toxic Effects of Urethane Dimethacrylate on Macrophages Through Caspase Activation, Mitochondrial Dysfunction, and Reactive Oxygen Species Generation

Urethane dimethacrylate (UDMA) is a dimethacrylate-based resin monomer that can react with other related monomers and inorganic particles, causing hydrophobic polymerization through cross-linking upon light activation. UDMA polymers are commonly used for the reconstruction and reinforcement of teeth and bones. UDMA can become unbound and be released from light-cured polymer resins. Thus far, no evidence exists on the toxic effects of UDMA and its related working mechanisms for macrophages. Therefore, in the present study, we investigated the cytotoxicity, mode of cell death, DNA damage, caspase activities, mitochondrial dysfunction, and reactive oxygen species (ROS) generation in RAW264.7 macrophages treated with UDMA using the lactate dehydrogenase (LDH) assay kit, Annexin V-FITC and PI assays, micronucleus formation and comet assay, caspase fluorometric assay, JC-1 assay, and 2ʹ,7ʹ-dichlorofluorescin diacetate (DCFH-DA) assay, respectively. Our results show that UDMA induced cytotoxicity; apoptosis and necrosis; genotoxicity, which is also called DNA damage; increased caspase-3, -8, and -9 activities; mitochondrial dysfunction; and intracellular ROS generation in a concentration-dependent manner in RAW264.7 macrophages. Thus, based on the observed inhibited concentration parallel trends, we concluded that UDMA induces toxic effects in macrophages. Furthermore, UDMA-induced intracellular ROS generation, cytotoxicity, and DNA damage were reduced by N-acetyl-L-cysteine.

Air Pollution and Covid-19: The Role of Particulate Matter in the Spread and Increase of Covid-19's Morbidity and Mortality

Sars-cov-2 virus (Covid-19) is a member of the coronavirus family and is responsible for the pandemic recently declared by the World Health Organization. A positive correlation has been observed between the spread of the virus and air pollution, one of the greatest challenges of our millennium. Covid-19 could have an air transmission and atmospheric particulate matter (PM) could create a suitable environment for transporting the virus at greater distances than those considered for close contact. Moreover, PM induces inflammation in lung cells and exposure to PM could increase the susceptibility and severity of the Covid-19 patient symptoms. The new coronavirus has been shown to trigger an inflammatory storm that would be sustained in the case of pre-exposure to polluting agents. In this review, we highlight the potential role of PM in the spread of Covid-19, focusing on Italian cities whose PM daily concentrations were found to be higher than the annual average allowed during the months preceding the epidemic. Furthermore, we analyze the positive correlation between the virus spread, PM, and angiotensin-converting enzyme 2 (ACE2), a receptor involved in the entry of the virus into pulmonary cells and inflammation.

The role of MDM2-p53 axis dysfunction in the hepatocellular carcinoma transformation

Liver cancer is the second most frequent cause of cancer-related death globally. The main histological subtype is hepatocellular carcinoma (HCC), which is derived from hepatocytes. According to the epidemiologic studies, the most important risk factors of HCC are chronic viral infections (HBV, HCV, and HIV) and metabolic disease (metabolic syndrome). Interestingly, these carcinogenic factors that contributed to HCC are associated with MDM2-p53 axis dysfunction, which presented with inactivation of p53 and overactivation of MDM2 (a transcriptional target and negative regulator of p53). Mechanically, the homeostasis of MDM2-p53 feedback loop plays an important role in controlling the initiation and progression of HCC, which has been found to be dysregulated in HCC tissues. To maintain long-term survival in hepatocytes, hepatitis viruses have lots of ways to destroy the defense strategies of hepatocytes by inducing TP53 mutation and silencing, promoting MDM2 overexpression, accelerating p53 degradation, and stabilizing MDM2. As a result, genetic instability, chronic ER stress, oxidative stress, energy metabolism switch, and abnormalities in antitumor genes can be induced, all of which might promote hepatocytes' transformation into hepatoma cells. In addition, abnormal proliferative hepatocytes and precancerous cells cannot be killed, because of hepatitis viruses-mediated exhaustion of Kupffer cells and hepatic stellate cells (HSCs) and CD4+T cells by disrupting their MDM2-p53 axis. Moreover, inefficiency of hepatic immune response can be further aggravated when hepatitis viruses co-infected with HIV. Unlike with chronic viral infections, MDM2-p53 axis might play a dual role in glucolipid metabolism of hepatocytes, which presented with enhancing glucolipid catabolism, but promoting hepatocyte injury at the early and late stages of glucolipid metabolism disorder. Oxidative stress, fatty degeneration, and abnormal cell growth can be detected in hepatocytes that were suffering from glucolipid metabolism disorder, and all of which could contribute to HCC initiation. In this review, we focus on the current studies of the MDM2-p53 axis in HCC, and specifically discuss the impact of MDM2-p53 axis dysfunction by viral infection and metabolic disease in the transformation of normal hepatocytes into hepatoma cells. We also discuss the therapeutic avenues and potential targets that are being developed to normalize the MDM2-p53 axis in HCC.

Diabetes aggravates renal ischemia and reperfusion injury in rats by exacerbating oxidative stress, inflammation, and apoptosis

Diabetic patients are more susceptible to renal ischemia/reperfusion (I/R) injury (RI/RI) and have a poor prognosis, but the underlying mechanism remains unclear. The present study aimed to examine whether diabetes could worsen acute kidney injury induced by I/R in rats and clarify its mechanism. Control and streptozotocin-induced diabetic rats were subjected to 45 min renal pedicle occlusion followed by 24 h reperfusion. Tert-butylhydroquinone (TBHQ, 16.7 mg/kg) was administrated intraperitoneally 3 times at intervals of 8 h before ischemia. Serum and kidneys were harvested after reperfusion to evaluate renal function and histological injury. Enzyme-linked immunosorbent assays were used to test pro-inflammatory cytokines. Terminal deoxynucleotidyl-transferase-mediated dUTP nick-end labeling assays were used to detect apoptotic cells, and western blotting was performed to determine the expression of B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax), and cleaved caspase-3, as well as oxidative stress and inflammation-related proteins, such as nuclear factor-erythroid 2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), Toll-like receptor 4 (TLR4), and nuclear factor-κB (NF-κB). Compared with control animals, diabetic rats undergoing I/R exhibited more severe tubular damage and renal dysfunction. Diabetes exacerbated oxidative stress, the inflammatory response, and apoptosis after renal I/R by enhancing TLR4/NF-κB signaling and blocking the Nrf2/HO-1 pathway. RI/RI in diabetic rats was attenuated by pretreatment with TBHQ (a Nrf2 agonist), which exerted anti-inflammatory and anti-apoptotic properties by inhibiting NF-κB signaling. These findings indicate that hyperglycemia exacerbates RI/RI by intensifying oxidative stress, inflammation, and apoptosis. Antioxidant pretreatment may alleviate RI/RI in diabetic patients.

Association Between Metabolic and Hormonal Derangements and Professional Exposure to Urban Pollution in a High Intensity Traffic Area

Rationale: Studies suggest a relation between exposure to air particulate matter (PM)_2.5 pollution and greater cardiovascular morbidity, as well as increased risk for obesity and diabetes. We aimed to identify association(s) between nutritional and metabolic status and exposure to environmental pollution in a cohort of policemen exposed to high levels of air pollution. Methods: We considered adult municipal policemen, working in an urban area at high-traffic density with documented high levels of air PM_2.5 (exposed group) compared to non-exposed policemen. Clinical characteristics, including the presence/absence of metabolic syndrome, were recorded, and serum biomarkers, including adiponectin, leptin, and ghrelin, were assessed. Results: One hundred ninety-nine participants were enrolled, 100 in the exposed group and 99 in the non-exposed group. Metabolic syndrome was documented in 32% of exposed group and in 52.5% of non-exposed group (P = 0.008). In the exposed group, we found a positive correlation between body mass index and serum leptin as well as in the non-exposed group (P < 0.0001). Within the exposed group, subjects with metabolic syndrome showed lower serum adiponectin (P < 0.0001) and higher leptin (P = 0.002) levels with respect to those without metabolic syndrome, whereas in the non-exposed group, subjects with metabolic syndrome showed only higher leptin levels when compared to those without metabolic syndrome (P = 0.01). Among the participants with metabolic syndrome, we found lower adiponectin levels in those of the exposed group with respect to the non-exposed ones (P = 0.007). When comparing the exposed and non-exposed groups, after stratifying participants for Homeostatic Model Assessment for Insulin Resistance >2.5, we found lower adiponectin levels in those of the exposed group with respect to the non-exposed ones (P = 0.038). Conclusions: Exposure to air PM pollution was associated with lower levels of adiponectin in adult males with metabolic syndrome.

Gene Expression Analysis to Investigate Biological Networks Underlying Nasal Inflammatory Dysfunctions Induced by Diesel Exhaust Particles Using an In Vivo System

OBJECTIVES

Diesel exhaust particles (DEP)s are notorious ambient pollutants composed of a complex mixture of a carbon core and diverse chemical irritants. Several studies have demonstrated significant relationships between DEP exposure and serious nasal inflammatory response in vitro, but available information regarding underlying networks in terms of gene expression changes has not sufficiently explained potential mechanisms of DEP-induced nasal damage, especially in vivo.

METHODS

In the present study, we identified DEP-induced gene expression profiles under short-term and long-term exposure, and identified signaling pathways based on microarray data for understanding effects of DEP exposure in the mouse nasal cavity.

RESULTS

Alteration in gene expression due to DEP exposure provokes an imbalance of the immune system via dysregulated inflammatory markers, predicted to disrupt protective responses against harmful exogenous substances in the body. Several candidate markers were identified after validation using qRT-PCR, including S100A9, CAMP, IL20, and S100A8.

CONCLUSIONS

Although further mechanistic studies are required for verifying the utility of the potential biomarkers suggested by the present study, our in vivo results may provide meaningful suggestions for understanding the complex cellular signaling pathways involved in DEP-induced nasal damages.

Mixture Effects of Diesel Exhaust and Metal Oxide Nanoparticles in Human Lung A549 Cells

Airborne ultrafine particles (UFP) mainly derive from combustion sources (e.g., diesel exhaust particles—DEP), abrasion sources (non-exhaust particles) or from the unintentional release of engineered nanoparticles (e.g., metal oxide nanoparticles—NPs), determining human exposure to UFP mixtures. The aim of the present study was to analyse the combined in vitro effects of DEP and metal oxide NPs (ZnO, CuO) on human lung A549 cells. The mixtures and the relative single NPs (DEP, ZnO, CuO) were characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and inductively coupled plasma-optic emission spectroscopy (ICP-OES). Cells were exposed for different times (3–72 h) to mixtures of standard DEP at a subcytotoxic concentration and ZnO and CuO at increasing concentrations. At the end of the exposure, the cytotoxicity was assessed by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) and clonogenic tests, the pro-inflammatory potential was evaluated by interleukin-8 (IL-8) release and the cell morphology was investigated by fluorescence and transmission electron microscopy. The obtained results suggest that the presence of DEP may introduce new physico-chemical interactions able to increase the cytotoxicity of ZnO and to reduce that of CuO NPs.

Potential role of polycyclic aromatic hydrocarbons as mediators of cardiovascular effects from combustion particles

Air pollution is the most important environmental risk factor for disease and premature death, and exposure to combustion particles from vehicles is a major contributor. Human epidemiological studies combined with experimental studies strongly suggest that exposure to combustion particles may enhance the risk of cardiovascular disease (CVD), including atherosclerosis, hypertension, thrombosis and myocardial infarction.In this review we hypothesize that adhered organic chemicals like polycyclic aromatic hydrocarbons (PAHs), contribute to development or exacerbation of CVD from combustion particles exposure. We summarize present knowledge from existing human epidemiological and clinical studies as well as experimental studies in animals and relevant in vitro studies. The available evidence suggests that organic compounds attached to these particles are significant triggers of CVD. Furthermore, their effects seem to be mediated at least in part by the aryl hydrocarbon receptor (AhR). The mechanisms include AhR-induced changes in gene expression as well as formation of reactive oxygen species (ROS) and/or reactive electrophilic metabolites. This is in accordance with a role of PAHs, as they seem to be the major chemical group on combustion particles, which bind AhR and/or is metabolically activated by CYP-enzymes. In some experimental models however, it seems as PAHs may induce an inflammatory atherosclerotic plaque phenotype irrespective of DNA- and/or AhR-ligand binding properties. Thus, various components and several signalling mechanisms/pathways are likely involved in CVD induced by combustion particles.We still need to expand our knowledge about the role of PAHs in CVD and in particular the relative importance of the different PAH species. This warrants further studies as enhanced knowledge on this issue may amend risk assessment of CVD caused by combustion particles and selection of efficient measures to reduce the health effects of particular matters (PM).

Transcription factor Nrf2 induces the up-regulation of lncRNA TUG1 to promote progression and adriamycin resistance in urothelial carcinoma of the bladder

Background

Taurine-upregulated gene 1 (TUG1) has been documented to be implicated in carcinogenesis and chemoresistance in solid tumors. Here, we explored the biological role and regulatory mechanism of TUG1 in progression and chemoresistance of urothelial carcinoma of the bladder (UCB).

Methods

Nuclear factor-erythroid 2 (NF-E2)-related factor 2 (Nrf2) mRNA and TUG1 expression was determined by quantitative reverse transcription polymerase chain reaction. Western blot was performed to determine the protein levels of Nrf2, p-glycoprotein (p-gp), Ki-67 (Ki67), matrix metalloproteinase (MMP)-2 and MMP-9 and cleaved caspase-3. The effects of either Nrf2 or TUG1 knockdown on the proliferation, invasion, apoptosis and adriamycin (ADM) resistance of UCB cells were evaluated by CCK-8 assay, transwell invasion assay and flow cytometry analysis. Xenograft tumor assay was carried out to confirm the role of Nrf2 and TUG1 in ADM resistance of UCB cells in vivo.

Results

Nrf2 and TUG1 were upregulated in UCB tissues and cell lines. A positive correlation between Nrf2 and TUG1 expression was discovered in UCB tissues. Moreover, Nrf2 and TUG1 expression levels were higher in ADM-resistant cells compared with those in parental cells. Furthermore, Nrf2 positively regulated the expression of TUG1 in UCB cells. Knockdown of either Nrf2 or TUG1 led to the inhibition of cell proliferation and invasion and promotion of cell apoptosis, accompanying with down-regulation of Ki67, MMP-2 and MMP-9 and up-regulation of cleaved caspase-3. Knockdown of either Nrf2 or TUG1 enhanced the sensitivity of BIU-87/ADM and T24/ADM cells to ADM, as indicated by decreased expression of p-gp. Besides, knockdown of either Nrf2 or TUG1 inhibited tumor growth in the absence or presence of ADM in vivo.

Conclusions

Nrf2 induces the up-regulation of TUG1 to promote progression and ADM resistance in UCB.

Protective effect of dexmedetomidine against diabetic hyperglycemia-exacerbated cerebral ischemia/reperfusion injury: An in vivo and in vitro study

AIMS

Dexmedetomidine (Dex) has been noted to have neuroprotective effect against cerebral ischemia-reperfusion (I/R) injury. However, the effect of Dex in diabetic hyperglycemia-exacerbated cerebral I/R injury and its underlying mechanism remain unclear.

MAIN METHODS

The infarct volume and brain edema were evaluated by 2,3,5-triphenyltetrazolium chloride staining and standard wet-dry method. Modified neurological severity score was utilized to assess the neurological deficits. The oxidative stress and inflammation were evaluated by detecting reactive oxygen species (ROS), malondialdehyde (MDA), tumor necrosis factor (TNF)-α and interleukin (IL)-1β. Terminal deoxynucleotidyl transferase dUTP nick end labeling assay and cell count kit-8 were applied to measure cell apoptosis and viability.

KEY FINDINGS

Dex treatment reduced infarct volume, decreased brain water content and improved neurological deficit in middle cerebral artery occlusion/reperfusion (MCAO/R) mice. Dex treatment reduced the levels of ROS, MDA, TNF-α and IL-1β in the entire middle cerebral artery territory of diabetic mice subjected to MCAO/R, as well as in primary culture of mouse hippocampal neurons stimulated with 50 mM glucose and oxygen glucose deprivation/reperfusion. Dex treatment inhibited neuronal apoptosis induced by diabetic hyperglycemia-exacerbated cerebral I/R injury. Dex upregulated nuclear factor of activated T-cells 5 (NFAT5) and Sirtuin 1 (SIRT1) expression, induced NF-E2-related factor 2 (Nrf2) translocation from cytoplasm to nucleus and inhibited the acetylation of Nrf2. However, these changes triggered by Dex treatment were abrogated by NFAT5 knockdown.

SIGNIFICANCE

Dex protects against diabetic hyperglycemia-exacerbated cerebral I/R injury through attenuation of oxidative stress, inflammation and apoptosis. The underlying mechanism is at least the NFAT5/SIRT1/Nrf2 signaling pathway dependent.

In Vivo Comparative Study on Acute and Sub-acute Biological Effects Induced by Ultrafine Particles of Different Anthropogenic Sources in BALB/c Mice

Exposure to ultrafine particles (UFPs) leads to adverse effects on health caused by an unbalanced ratio between UFPs deposition and clearance efficacy. Since air pollution toxicity is first direct to cardiorespiratory system, we compared the acute and sub-acute effects of diesel exhaust particles (DEP) and biomass burning-derived particles (BB) on bronchoalveolar Lavage Fluid (BALf), lung and heart parenchyma. Markers of cytotoxicity, oxidative stress and inflammation were analysed in male BALB/c mice submitted to single and repeated intra-tracheal instillations of 50 μg UFPs. This in-vivo study showed the activation of inflammatory response (COX-2 and MPO) after exposure to UFPs, both in respiratory and cardiovascular systems. Exposure to DEP results also in pro- and anti-oxidant (HO-1, iNOS, Cyp1b1, Hsp70) protein levels increase, although, stress persist only in cardiac tissue under repeated instillations. Statistical correlations suggest that stress marker variation was probably due to soluble components and/or mediators translocation of from first deposition site. This mechanism, appears more important after repeated instillations, since inflammation and oxidative stress endure only in heart. In summary, chemical composition of UFPs influenced the activation of different responses mediated by their components or pro-inflammatory and pro-oxidative molecules, indicating DEP as the most damaging pollutant in the comparison.

Early Proteome Shift and Serum Bioactivity Precede Diesel Exhaust-induced Impairment of Cardiovascular Recovery in Spontaneously Hypertensive Rats

Single circulating factors are often investigated to explain air pollution-induced cardiovascular dysfunction, yet broader examinations of the identity and bioactivity of the entire circulating milieu remain understudied. The purpose of this study was to determine if exposure-induced cardiovascular dysfunction can be coupled with alterations in both serum bioactivity and the circulating proteome. Two cohorts of Spontaneously Hypertensive Rats (SHRs) were exposed to 150 or 500 μg/m³ diesel exhaust (DE) or filtered air (FA). In Cohort 1, we collected serum 1 hour after exposure for proteomics analysis and bioactivity measurements in rat aortic endothelial cells (RAECs). In Cohort 2, we assessed left ventricular pressure (LVP) during stimulation and recovery from the sympathomimetic dobutamine HCl, one day after exposure. Serum from DE-exposed rats had significant changes in 66 serum proteins and caused decreased NOS activity and increased VCAM-1 expression in RAECs. While rats exposed to DE demonstrated increased heart rate at the start of LVP assessments, heart rate, systolic pressure, and double product fell below baseline in DE-exposed rats compared to FA during recovery from dobutamine, indicating dysregulation of post-exertional cardiovascular function. Taken together, a complex and bioactive circulating milieu may underlie air pollution-induced cardiovascular dysfunction.

The Effect of Ganoderma Microsporum immunomodulatory proteins on alleviating PM2.5-induced inflammatory responses in pregnant rats and fine particulate matter-induced neurological damage in the offsprings

Fine particulate matter 2.5 (PM_2.5) induces free radicals and oxidative stress in animals, leading to a range of illnesses. In this study, Ganoderma Microsporum immunomodulatory (GMI) proteins were administered to alleviate PM_2.5-induced inflammatory responses in mother rats, and PM_2.5-induced inflammatory responses and neurological damage in their offspring. The results suggested that GMI administration decreased the risk of neurological disorders in mother rats and their offspring by reducing the white blood cell count, lessening inflammatory responses and PM_2.5-induced memory impairment, and preventing dendritic branches in the hippocampi from declining and microRNAs from PM_2.5-induced modulation.

Traffic-related particulate matter exposure induces nephrotoxicity in vitro and in vivo

Traffic emission is responsible for most small-sized particulate matter (PM) air pollution in urban areas. Several recent studies have indicated that traffic-related PM may aggravate kidney disease. Furthermore, exposure to particulate air pollution may be related to the risk of chronic kidney disease (CKD). However, the underlying molecular mechanisms have not been adequately addressed. In the present study, we studied the mechanisms of renal damage that might be associated with exposure to PM. In a real world of whole-body exposure to traffic-related PM model for 3-6 months, PM in urban ambient air can affect kidney function and induce autophagy, endoplasmic reticulum (ER) stress and apoptosis in kidney tissues. Exposure to traffic-related diesel particulate matter (DPM) led to a reduction in cell viability in human kidney tubular epithelial cells HK-2. DPM increased mitochondrial reactive oxygen species (ROS) and decreased the mitochondrial membrane potential. Furthermore, DPM induced ER stress and activated the unfolded protein response (UPR) pathway. Eventually, DPM exposure induced caspase pathways and triggered apoptosis. In addition, DPM induced autophagy through the inhibition of the Akt/mTOR pathway. Autophagy inhibition resulted in significantly increased cytotoxicity and apoptosis. These findings suggest that air pollution in urban areas may cause nephrotoxicity and autophagy as a protective role in PM-induced cytotoxicity.

1-Trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo) Induces the Apoptosis of Dopaminergic Neurons via Oxidative Stress and Neuroinflammation

Several in vitro studies have revealed the neurotoxicity of 1-trichloromethyl-1,2,3,4-tetrahydro-beta-carboline (TaClo). However, the underlying mechanism has not been completely elucidated, particularly in vivo. This study was designed to study the neurotoxicity of TaClo in vivo by stereotactically injecting TaClo into the striatum of Wistar rats. After the TaClo injections, rats were subjected to an open field test, and their distance travelled and tracks showed decreasing trends over time. The results of liquid chromatography-mass spectrometry analysis showed that the motor dysfunction of the TaClo-treated rats was accompanied by reduced dopamine levels in the striatum. Based on the diffusion tensor imaging data, the apparent diffusion coefficient of the nigrostriatal pathway was significantly increased, and subsequent histological staining revealed the demyelination of nigrostriatal fibres after the TaClo treatment. TaClo induced a loss of tyrosine hydroxylase-positive cells in the substantia nigra compacta. Regarding the underlying mechanism, TaClo caused oxidative stress in the nigrostriatal system by increasing the production of reactive oxygen species and reducing the mitochondria membrane potential. Meanwhile, the elevated expression of Iba-1, TNF-α, IL-6, Cox-2, and iNOS indicated microglial activation and a strong innate immune response in the nigrostriatal system. In addition, activated caspase-3 levels were increased. Thus, both mitochondrial impairments and the innate immune response are involved in TaClo-induced neurotoxicity.

Atorvastatin reverses the dysfunction of human umbilical vein endothelial cells induced by angiotensin II

Statins exert pleiotropic effects on endothelial cells, in addition to lowering cholesterol. This study evaluated angiotensin II (Ang II)-induced dysfunction in human umbilical vein endothelial cells (HUVECs), and the effects of atorvastatin (Ator) on induced HUVECs in vitro. The cytotoxicity of Ang II and Ator was determined by the MTT assay. A series of cellular responses were screened, including oxidative stress, cellular apoptosis, inflammatory response, autophagy, expression of endothelial nitric oxide synthase and the angiogenic function of HUVECs. Ator returned these cellular responses to a normal level. The present study also examined cellular organelle dysfunction. In HUVECs, Ang II triggered mitochondrial damage, as demonstrated by a decreased mitochondrial membrane potential, while Ator attenuated this Ang II-induced damage. The observed cellular dysfunction may cause endothelial senescence due to excessive cell injury. The current study examined several aging markers, which revealed that these disorders of cellular functions triggered endothelial senescence, which was delayed by Ator. Ator also suppressed Ang II-induced angiogenesis damage. The data presented in this study strongly suggested that Ang II induced a series of processes that lead to cellular dysfunction in HUVECs, including oxidative stress, inflammation, and mitochondrial damage, leading to apoptosis and endothelial senescence. However, Ator significantly reversed these effects and modulated intracellular stability. The present study indicated that Ator serves an antagonistic role against HUVEC dysfunction and may potentially prevent several diseases, including coronary disease and atherosclerosis, by maintaining cellular homeostasis.

Transcriptional profiling of human bronchial epithelial cell BEAS-2B exposed to diesel and biomass ultrafine particles

BACKGROUND

Emissions from diesel vehicles and biomass burning are the principal sources of primary ultrafine particles (UFP). The exposure to UFP has been associated to cardiovascular and pulmonary diseases, including lung cancer. Although many aspects of the toxicology of ambient particulate matter (PM) have been unraveled, the molecular mechanisms activated in human cells by the exposure to UFP are still poorly understood. Here, we present an RNA-seq time-course experiment (five time point after single dose exposure) used to investigate the differential and temporal changes induced in the gene expression of human bronchial epithelial cells (BEAS-2B) by the exposure to UFP generated from diesel and biomass combustion. A combination of different bioinformatics tools (EdgeR, next-maSigPro and reactome FI app-Cytoscape and prioritization strategies) facilitated the analyses the temporal transcriptional pattern, functional gene set enrichment and gene networks related to cellular response to UFP particles.

RESULTS

The bioinformatics analysis of transcriptional data reveals that the two different UFP induce, since the earliest time points, different transcriptional dynamics resulting in the activation of specific genes. The functional enrichment of differentially expressed genes indicates that the exposure to diesel UFP induces the activation of genes involved in TNFα signaling via NF-kB and inflammatory response, and hypoxia. Conversely, the exposure to ultrafine particles from biomass determines less distinct modifications of the gene expression profiles. Diesel UFP exposure induces the secretion of biomarkers associated to inflammation (CCXL2, EPGN, GREM1, IL1A, IL1B, IL6, IL24, EREG, VEGF) and transcription factors (as NFE2L2, MAFF, HES1, FOSL1, TGIF1) relevant for cardiovascular and lung disease. By means of network reconstruction, four genes (STAT3, HIF1a, NFKB1, KRAS) have emerged as major regulators of transcriptional response of bronchial epithelial cells exposed to diesel exhaust.

CONCLUSIONS

Overall, this work highlights modifications of the transcriptional landscape in human bronchial cells exposed to UFP and sheds new lights on possible mechanisms by means of which UFP acts as a carcinogen and harmful factor for human health.

Inhaled diesel exhaust alters the allergen-induced bronchial secretome in humans

Diesel exhaust (DE) is a paradigm for traffic-related air pollution. Human adaptation to DE is poorly understood and currently based on oversimplified models. DE promotes allergic responses, but protein expression changes mediated by this interaction have not been systematically investigated. The aim of this study was to define the effect of inhaled DE on allergen-induced proteins in the lung.

We performed a randomised and blinded controlled human crossover exposure study. Participants inhaled filtered air or DE; thereafter, contralateral lung segments were challenged with allergen or saline. Using label-free quantitative proteomics, we comprehensively defined DE-mediated alteration of allergen-driven secreted proteins (secretome) in bronchoalveolar lavage. We further examined expression of proteins selected from the secretome data in independent validation experiments using Western blots, ELISA and immunohistochemistry.

We identified protein changes unique to co-exposure (DE+allergen), undetected with mono-exposures (DE or allergen alone). Validation studies confirmed that specific proteins (e.g.the antimicrobial peptide cystatin-SA) were significantly enhanced with DE+allergen compared to either mono-exposure.

This study demonstrates that common environmental co-exposures can uniquely alter protein responses in the lungs, illuminating biology that mono-exposures cannot. This study highlights the value of complex humanin vivomodels in detailing airway responses to inhaled pollution.

Human peripheral blood mononuclear cells (PBMCs) from smokers release higher levels of IL-1-like cytokines after exposure to combustion-generated ultrafine particles

Ultrafine particles (UFP) generated by combustion processes are often associated with adverse health effects. However, little is known about the inflammatory processes generated by UFP that may underlie their toxicological activity. Murine macrophages (J774.1 cells) and human peripheral blood mononuclear cells (PBMCs) were used to evaluate the molecular mechanism underlying the pro-inflammatory activity of UFP. The addition of soot particles to J774.1 cells induced a concentration-dependent release of IL-1α, IL-1β and IL-33 This effect was not associated with cell death and, in contrast to literature, was pronounced at very low concentrations (5–100 pg/ml). Similarly, UFP induced the release of IL-1α, IL-18 and IL-33 by PBMCs. However, this effect was solely observed in PBMCs obtained from smokers, as the PBMCs from non-smokers instead released higher levels of IL-10. The release of these cytokines after UFP exposure was caspase-1- and NLRP3 inflammasome-dependent in PBMCs from healthy smokers, whereas IL-1α release was calpain-dependent. These results show that UFP at very low concentrations are able to give rise to an inflammatory process that is responsible for IL-1α, IL-18 and IL-33 release, which is pronounced in PBMCs from smokers, confirming that these individuals are especially susceptible to inflammatory-based airway diseases once exposed to air pollution.