Effect of Polyaryl Hydrocarbons on Cytotoxicity in Monocytic Cells: Potential Role of Cytochromes P450 and Oxidative Stress Pathways

Exploring the Cellular Impact of Size-Segregated Cigarette Aerosols: Insights into Indoor Particulate Matter Toxicity and Potential Therapeutic Interventions

Exposure to anthropogenic aerosols has been associated with a variety of adverse health effects, increased morbidity, and premature death. Although cigarette smoke poses one of the most significant public health threats, the cellular toxicity of particulate matter contained in cigarette smoke has not been systematically interrogated in a size-segregated manner. In this study, we employed a refined particle size classification to collect cigarette aerosols, enabling a comprehensive assessment and comparison of the impacts exerted by cigarette aerosol extract (CAE) on SH-SY5Y, HEK293T, and A549 cells. Exposure to CAE reduced cell viability in a dose-dependent manner, with organic components having a greater impact and SH-SY5Y cells displaying lower tolerance compared to HEK293T and A549 cells. Moreover, CAE was found to cause increased oxidative stress, mitochondrial dysfunction, and increased levels of apoptosis, pyroptosis, and autophagy, leading to increased cell death. Furthermore, we found that rutin, a phytocompound with antioxidant potential, could reduce intracellular reactive oxygen species and protect against CAE-triggered cell death. These findings underscore the therapeutic potential of antioxidant drugs in mitigating the adverse effects of cigarette aerosol exposure for better public health outcomes.

Exposure to environmental pollutants and genetic variants related to oxidative stress and xenobiotic metabolism-Association with prostate cancer

This study assessed whether genetic variants coding for certain enzymes involved in xenobiotic detoxification, antioxidant defences and DNA repair, along with exposure to environmental chemicals, were associated with an increased prostate cancer (PCa) risk. The study population consisted of 300 men (150 PCa cases and 150 controls) which underwent prostate biopsy as their serum prostate specific antigen (PSA) levels were greater than 4 ng/ml. Genetic variants in GSTM1, GSTP1, SOD2, CAT, GPX1, XRCC1 were determined and data for chemical exposures was obtained through a structured questionnaire and by biomonitoring in a subsample of cases and controls. High serum PSA levels were associated with a greater risk of PCa, while physical exercise appears to exert a protective effect against its development. In addition, elevated urinary levels of certain organic pollutants, such as benzo(a)pyrene (BaP), bisphenol A (BPA), and ethyl-paraben (EPB), were associated with an increased risk of PCa.

Tumor diagnosis using carbon-based quantum dots: Detection based on the hallmarks of cancer

Carbon-based quantum dots (CQDs) have been shown to have promising application value in tumor diagnosis. Their use, however, is severely hindered by the complicated nature of the nanostructures in the CQDs. Furthermore, it seems impossible to formulate the mechanisms involved using the inadequate theoretical frameworks that are currently available for CQDs. In this review, we re-consider the structure-property relationships of CQDs and summarize the current state of development of CQDs-based tumor diagnosis based on biological theories that are fully developed. The advantages and deficiencies of recent research on CQDs-based tumor diagnosis are thus explained in terms of the manifestation of nine essential changes in cell physiology. This review makes significant progress in addressing related problems encountered with other nanomaterials.

Benzo[a]pyrene induces NLRP1 expression and promotes prolonged inflammasome signaling

Benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon in the air, triggers pulmonary inflammation. This study focused on BaP-induced inflammation in the alveolar epithelium. A549 cells were stimulated with BaP for four days. BaP treatment markedly increased NLRP1 expression but slightly decreased NLRP3. Furthermore, aryl hydrocarbon receptor (AhR) knockdown displayed no increase in BaP-induced NLRP1 expression. Similar results were also observed by blocking reactive oxygen species (ROS), which is mediated through AhR, suggesting that the AhR-ROS axis operates in BaP-induced NLRP1 expression. p53 involvement in ROS-mediated NLRP1 induction has also been implied. When we confirmed inflammasome activation in cells treated with BaP for four days, while BaP transiently activated NLRP3, it predominantly activated the NLRP1 inflammasome. These findings have led to the conclusion that BaP could be a potential ligand for the NLRP1 inflammasome persistently observed in the lung epithelium. Our study may provide additional evidence for the sustained pulmonary inflammation caused by environmental air pollution.

Polymorphisms of Antioxidant Enzymes SOD2 (rs4880) and GPX1 (rs1050450) Are Associated with Bladder Cancer Risk or Its Aggressiveness

Background and Objectives: Oxidative stress induced by increased reactive oxygen species (ROS) production plays an important role in carcinogenesis. The entire urinary tract is continuously exposed to numerous potentially mutagenic environmental agents which generate ROS during their biotransformation. In first line defense against free radicals, antioxidant enzymes superoxide dismutase (SOD2) and glutathione peroxidase (GPX1) both have essential roles. Altered enzyme activity and decreased ability of neutralizing free oxygen radicals as a consequence of genetic polymorphisms in genes encoding these two enzymes are well described so far. This study aimed to investigate the association of GPX1 (rs1050450) and SOD2 (rs4880) genetic variants with the urothelial bladder cancer (UBC) risk independently and in combination with smoking. Furthermore, we aimed to determine whether the UBC stage and pathological grade were influenced by GPX1 and SOD2 polymorphisms. Material and Methods: The study population included 330 patients with UBC (mean age 65 ± 10.3 years) and 227 respective controls (mean age 63.4 ± 7.9 years). Single nucleotide polymorphism (SNP) of GPX1 (rs1050450) was analyzed using the PCR-RFLP, while SOD2 (rs4880) SNP was analyzed using the q-PCR method. Results: Our results showed that UBC risk was significantly increased among carriers of at least one variant SOD2 Val allele compared to the SOD2 Ala16Ala homozygotes (OR = 1.55, p = 0.03). Moreover, this risk was even more pronounced in smokers with at least one variant SOD2 Val allele, since they have even 7.5 fold higher UBC risk (OR = 7.5, p < 0.001). Considering GPX1 polymorphism, we have not found an association with UBC risk. However, GPX1 genotypes distribution differed significantly according to the tumor stage (p ˂ 0.049) and pathohistological grade (p ˂ 0.018). Conclusion: We found that SOD2 genetic polymorphism is associated with the risk of UBC development independently and in combination with cigarette smoking. Furthermore, we showed that GPX1 genetic polymorphism is associated with the aggressiveness of the disease.

Genetic variants of antioxidant enzymes and environmental exposures as molecular biomarkers associated with the risk and aggressiveness of bladder cancer

Bladder cancer (BC) is one of the top 10 most common tumours worldwide; however, no molecular markers are currently available for tumour management and follow-up. BC could benefit from molecular biomarkers in environmental disease, which provide mechanistic understanding of individual susceptibility to exposure-related cancers and allow characterizing genetic alterations in the molecular pathway for malignancy. This case-control study performed a molecular analysis in 99 BC and 125 controls. Buccal swabs were collected to assess SNPs in eleven genes coding for xenobiotic detoxification enzymes, cellular antioxidant defences, and hormone synthesis and signalling (NAT2 (rs1801280), GPX1 (rs1050450 and rs17650792), TXNRD1 (rs7310505), PRDX3 (rs3740562), PON1 (rs662), SOD1 (rs10432782), SOD2 (rs4880), CAT (rs1001179), CYP17A1 (rs743572) and ESR1 (rs746432)). A structured questionnaire was administered to study participants to assess environmental and dietary chemical exposures. Several miRNAs associated with BC and detoxification/antioxidant pathways were analysed in a subsample of the study population, including miR-93-5p, miR-221-3p, miR-126, miR-27a-3p, miR-193b, and miR-193a-5p. Levels of selected environmental pollutants (polycyclic aromatic hydrocarbons and endocrine disrupting chemicals) were determined in urine from a subsample of BC cases and controls. We found that CYP17A1, CAT, SOD1, ESR1, PON1, and GPX1 (rs17650792) were associated with BC risk. Furthermore, exposure to smoke and/or dust, and alcohol intake were identified as risk factors for BC. Increased urinary levels of benzo[a]pyrene and bisphenol A were observed in BC patients relative to controls, along with an increased expression of miR-193b, miR-27a and miR-93-5p in BC. Nevertheless, further studies with a larger sample size are warranted to confirm these exploratory results. This study also shows that the combination of genetic markers (PON1 and CYP17A1) and miRNA (miR-221-3p and miR-93-5p) open a new scenario in the use of non-invasive biomarkers in the stratification of BC to guide personalized medicine, which is extremely urged in the current clinical setting.

Effect of benzo(a)pyrene on oxidative stress and inflammatory mediators in astrocytes and HIV-infected macrophages

BACKGROUND

Benzo(a)pyrene (BaP), an important polycyclic aromatic hydrocarbons (PAH) component of cigarette/tobacco smoking, is known to cause adverse health effects and is responsible for various life-threatening conditions including cancer. However, it is not yet clear whether BaP contributes to the macrophage- and astrocyte-mediated inflammatory response.

METHODS

We examined the acute (up to 72 h) effects of BaP on the expression of antioxidant enzymes (AOEs), cytokines/chemokines, and cytochromes P450 (CYP) enzymes in astrocytic cell lines, SVGA, and chronically HIV-infected U1 macrophage. The treated cells were examined for mRNA, protein levels of CYPs, AOEs superoxide dismutase-1 (SOD1) and catalase (CAT), cytokines/chemokines, using Western blot, multiplex ELISA, and reactive oxygen species (ROS) by flow cytometry analysis.

RESULTS

Upon acute exposure, BaP (1 μM) showed a significant increase in the mRNA levels of CYPs (CYP1A1 and CYP1B1), and pro-inflammatory cytokine IL-1β in SVGA cells following BaP for 24, 48, and 72h. In addition, we observed a significant increase in the mRNA levels of SOD1 and CAT at 24h of BaP treatment. In contrast, BaP did not exert any change in the protein expression of AOEs and CYP enzymes. In U1 cells, however, we noticed an interesting increase in the levels of MCP-1 as well as a modest increase in TNFα, IL-8 and IL-1β levels observed at 72 h of BaP treatment but could not reach to statistically significant level.

CONCLUSIONS

Overall, these results suggest that BaP contributes in part to macrophage and astrocyte-mediated neuroinflammation by mainly inducing IL-1β and MCP-1 production, which is likely to occur with the involvement of CYP and/or oxidative stress pathways.

Staphylococcus epidermidis WF2R11 Suppresses PM2.5-Mediated Activation of the Aryl Hydrocarbon Receptor in HaCaT Keratinocytes

The skin supports a diverse microbiome whose imbalance is related to skin inflammation and diseases. Exposure to fine particulate matter (PM_2.5), a major air pollutant, can adversely affect the skin microbiota equilibrium. In this study, the effect and mechanism of PM_2.5 exposure in HaCaT keratinocytes were investigated. PM_2.5 stimulated the aryl hydrocarbon receptor (AhR) to produce reactive oxygen species (ROS) in HaCaT cells, leading to mitochondrial dysfunction and intrinsic mitochondrial apoptosis. We observed that the culture medium derived from a particular skin microbe, Staphylococcus epidermidis WF2R11, remarkably reduced oxidative stress in HaCaT cells caused by PM_2.5-mediated activation of the AhR pathway. Staphylococcus epidermidis WF2R11 also exhibited inhibition of ROS-induced inflammatory cytokine secretion. Herein, we demonstrated that S. epidermidis WF2R11 could act as a suppressor of AhRs, affect cell proliferation, and inhibit apoptosis. Our results highlight the importance of the clinical application of skin microbiome interventions in the treatment of inflammatory skin diseases.

Comparing the effects of an exposure to a polycyclic aromatic hydrocarbon mixture versus individual polycyclic aromatic hydrocarbons during monocyte to macrophage differentiation: Mixture exposure results in altered immune metrics

Polycyclic aromatic hydrocarbons (PAHs) are generated by the incomplete combustion of carbon. Exposures correlate with systemic immune dysfunction and overall immune suppression. Real-world exposures to PAHs are almost always encountered as mixtures; however, research overwhelmingly centers on isolated exposures to a single PAH, benzo[a]pyrene (B[a]P). Here, a human monocyte line (U937) was exposed to B[a]P, benz[a]anthracene (B[a]A), or a mixture of six PAHs (6-MIX) to assess the differential toxicity on monocytes. Further, monocytes were exposed to PAHs with and without CYP1A1 inhibitors during macrophage differentiation to delineate PAH exposure and PAH metabolism-driven alterations to the immune response. U937 monocytes exposed to B[a]P, B[a]A, or 6-MIX had higher levels of cellular health and growth not observed following equimolar exposures to other individual PAHs. PAH exposures during differentiation did not alter monocyte-derived macrophage (MDM) numbers; however, B[a]A and 6-MIX exposures significantly altered M1/M2 polarization in a CYP1A1-dependent manner. U937-MDM adherence was differentially suppressed by all three PAH treatments with 6-MIX exposed U937-MDM having significantly more adhesion than U937-MDM exposed to either individual PAH. Finally, 6-MIX exposures during differentiation reduced U937-MDM endocytic function significantly less than B[a]A exposed cells. Exposure to a unique PAH mixture during U937-MDM differentiation resulted in mixture-specific alterations of pro-inflammatory markers compared to individual PAH exposures. While subtle, these differences highlight the probability that using a model PAH, B[a]P, may not accurately reflect the effects of PAH mixture exposures. Therefore, future studies should include various PAH mixtures that encompass probable real-world PAH exposures for the endpoints under investigation.

Impact of whole-body versus nose-only inhalation exposure systems on systemic, respiratory, and cardiovascular endpoints in a 2-month cigarette smoke exposure study in the ApoE-/- mouse model

Cigarette smoking is one major modifiable risk factor in the development and progression of chronic obstructive pulmonary disease and cardiovascular disease. To characterize and compare cigarette smoke (CS)-induced disease endpoints after exposure in either whole-body (WB) or nose-only (NO) exposure systems, we exposed apolipoprotein E-deficient mice to filtered air (Sham) or to the same total particulate matter (TPM) concentration of mainstream smoke from 3R4F reference cigarettes in NO or WB exposure chambers (EC) for 2 months. At matching TPM concentrations, we observed similar concentrations of carbon monoxide, acetaldehyde, and acrolein, but higher concentrations of nicotine and formaldehyde in NOEC than in WBEC. In both exposure systems, CS exposure led to the expected adaptive changes in nasal epithelia, altered lung function, lung inflammation, and pronounced changes in the nasal epithelial transcriptome and lung proteome. Exposure in the NOEC caused generally more severe histopathological changes in the nasal epithelia and a higher stress response as indicated by body weight decrease and lower blood lymphocyte counts compared with WB exposed mice. Erythropoiesis, and increases in total plasma triglyceride levels and atherosclerotic plaque area were observed only in CS-exposed mice in the WBEC group but not in the NOEC group. Although the composition of CS in the breathing zone is not completely comparable in the two exposure systems, the CS-induced respiratory disease endpoints were largely confirmed in both systems, with a higher magnitude of severity after NO exposure. CS-accelerated atherosclerosis and other pro-atherosclerotic factors were only significant in WBEC.

Carbon-Based Quantum Dots with Solid-State Photoluminescent: Mechanism, Implementation, and Application

Carbon-based quantum dots (CQDs), including spherical carbon dots and graphene quantum dots, are an emerging class of photoluminescent (PL) materials with unique properties. Great progress has been made in the design and fabrication of high-performance CQDs, however, the challenge of developing solid-state PL CQDs have aroused great interest among researchers. A clear PL mechanism is the basis for the development of high-performance solid-state CQDs for light emission and is also a prerequisite for the realization of multiple practical applications. However, the extremely complex structure of a CQD greatly limits the understanding of the solid-state PL mechanism of CQDs. So far, a variety of models have been proposed to explain the PL of solid-state CQDs, but they have not been unified. This review summarizes the current understanding of the solid-state PL of solid-state CQDs from the perspective of energy band theory and electronic transitions. In addition, the common strategies for realizing solid-state PL in CQDs are also summarized. Furthermore, the applications of CQDs in the fields of light-emitting devices, anti-counterfeiting, fingerprint detection, etc., are proposed. Finally, a brief outlook is given, highlighting current problems, and directions for development of solid-state PL of CQDs.

Impact of airborne particulate matter on skin: a systematic review from epidemiology to in vitro studies

BACKGROUND

Air pollution is killing close to 5 million people a year, and harming billions more. Air pollution levels remain extremely high in many parts of the world, and air pollution-associated premature deaths have been reported for urbanized areas, particularly linked to the presence of airborne nano-sized and ultrafine particles.

MAIN TEXT

To date, most of the research studies did focus on the adverse effects of air pollution on the human cardiovascular and respiratory systems. Although the skin is in direct contact with air pollutants, their damaging effects on the skin are still under investigation. Epidemiological data suggested a correlation between exposure to air pollutants and aggravation of symptoms of chronic immunological skin diseases. In this study, a systematic literature review was conducted to understand the current knowledge on the effects of airborne particulate matter on human skin. It aims at providing a deeper understanding of the interactions between air pollutants and skin to further assess their potential risks for human health.

CONCLUSION

Particulate matter was shown to induce a skin barrier dysfunction and provoke the formation of reactive oxygen species through direct and indirect mechanisms, leading to oxidative stress and induced activation of the inflammatory cascade in human skin. Moreover, a positive correlation was reported between extrinsic aging and atopic eczema relative risk with increasing particulate matter exposure.

Differential packaging of inflammatory cytokines/ chemokines and oxidative stress modulators in U937 and U1 macrophages-derived extracellular vesicles upon exposure to tobacco constituents

Smoking, which is highly prevalent in HIV-infected populations, has been shown to exacerbate HIV replication, in part via the cytochrome P450 (CYP)-induced oxidative stress pathway. Recently, we have shown that extracellular vesicles (EVs), derived from tobacco- and/or HIV-exposed macrophages, alter HIV replication in macrophages by cell-cell interactions. We hypothesize that cigarette smoke condensate (CSC) and/or HIV-exposed macrophage-derived EVs carry relatively high levels of pro-oxidant and pro-inflammatory cargos and/or low levels of antioxidant and anti-inflammatory cargos, which are key mediators for HIV pathogenesis. Therefore, in this study, we investigated differential packaging of pro- and anti-inflammatory cytokines/chemokines and pro- and anti-oxidant contents in EVs after CSC exposure to myeloid cells (uninfected U937 and HIV-infected U1 cells). Our results showed that relatively long to short exposures with CSC increased the expression of cytokines in EVs isolated from HIV-infected U1 macrophages. Importantly, pro-inflammatory cytokines, especially IL-6, were highly packaged in EVs isolated from HIV-infected U1 macrophages upon both long and short-term CSC exposures. In general, anti-inflammatory cytokines, particularly IL-10, had a lower packaging in EVs, while packaging of chemokines was mostly increased in EVs upon CSC exposure in both HIV-infected U1 and uninfected U937 macrophages. Moreover, we observed higher expression of CYPs (1A1 and 1B1) and lower expression of antioxidant enzymes (SOD-1 and catalase) in EVs from HIV-infected U1 macrophages than in uninfected U937 macrophages. Together, they are expected to increase oxidative stress factors in EVs derived from HIV-infected U1 cells. Taken together, our results suggest packaging of increased level of oxidative stress and inflammatory elements in the EVs upon exposure to tobacco constituents and/or HIV to myeloid cells, which would ultimately enhance HIV replication in macrophages via cell-cell interactions.

Extracellular Vesicles in Smoking-Mediated HIV Pathogenesis and their Potential Role in Biomarker Discovery and Therapeutic Interventions

In the last two decades, the mortality rate in people living with HIV/AIDS (PLWHA) has decreased significantly, resulting in an almost normal longevity in this population. However, a large portion of this population still endures a poor quality of life, mostly due to an increased inclination for substance abuse, including tobacco smoking. The prevalence of smoking in PLWHA is consistently higher than in HIV negative persons. A predisposition to cigarette smoking in the setting of HIV potentially leads to exacerbated HIV replication and a higher risk for developing neurocognitive and other CNS disorders. Oxidative stress and inflammation have been identified as mechanistic pathways in smoking-mediated HIV pathogenesis and HIV-associated neuropathogenesis. Extracellular vesicles (EVs), packaged with oxidative stress and inflammatory agents, show promise in understanding the underlying mechanisms of smoking-induced HIV pathogenesis via cell-cell interactions. This review focuses on recent advances in the field of EVs with an emphasis on smoking-mediated HIV pathogenesis and HIV-associated neuropathogenesis. This review also provides an overview of the potential applications of EVs in developing novel therapeutic carriers for the treatment of HIV-infected individuals who smoke, and in the discovery of novel biomarkers that are associated with HIV-smoking interactions in the CNS.

Novel elvitegravir nanoformulation for drug delivery across the blood-brain barrier to achieve HIV-1 suppression in the CNS macrophages

The use of antiretroviral therapy (ART) has remarkably decreased the morbidity associated with HIV-1 infection, however, the prevalence of HIV-1-associated neurocognitive disorders (HAND) is still increasing. The blood-brain barrier (BBB) is the major impediment for penetration of antiretroviral drugs, causing therapeutics to reach only suboptimal level to the brain. Conventional antiretroviral drug regimens are not sufficient to improve the treatment outcomes of HAND. In our recent report, we have developed a poloxamer-PLGA nanoformulation loaded with elvitegravir (EVG), a commonly used antiretroviral drug. The nanoformulated EVG is capable of elevating intracellular drug uptake and simultaneously enhance viral suppression in HIV-1-infected macrophages. In this work, we identified the clinical parameters including stability, biocompatibility, protein corona, cellular internalization pathway of EVG nanoformulation for its potential clinical translation. We further assessed the ability of this EVG nanoformulation to cross the in vitro BBB model and suppress the HIV-1 in macrophage cells. Compared with EVG native drug, our EVG nanoformulation demonstrated an improved BBB model penetration cross the in vitro BBB model and an enhanced HIV-1 suppression in HIV-1-infected human monocyte-derived macrophages after crossing the BBB model without altering the BBB model integrity. Overall, this is an innovative and optimized treatment strategy that has a potential for therapeutic interventions in reducing HAND.

Extracellular Vesicles from Human Papilloma Virus-Infected Cervical Cancer Cells Enhance HIV-1 Replication in Differentiated U1 Cell Line

In the current study, we hypothesized that extracellular vesicles (EVs) secreted from human papilloma virus (HPV)-infected cervical cancer cells exacerbate human immunodeficiency virus (HIV)-1 replication in differentiated U1 cell line through an oxidative stress pathway. To test the hypothesis, we treated an HIV-1-infected macrophage cell line (U1) with HPV-infected Caski cell culture supernatant (CCS). We observed a significant increase in HIV-1 replication, which was associated with an increase in the expression of cytochrome P450 (CYPs 1A1 and 2A6) in the CCS-treated U1 cells. Furthermore, we isolated EVs from CCS (CCS-EVs), which showed the presence of CYPs (1A1, 2A6), superoxide dismutase 1 (SOD1), and HPV oncoproteins HPV16 E6. CCS-EVs when exposed to the U1 cells also significantly increased HIV-1 replication. Treatment of antioxidant, CYP1A1 and CYP2A6 inhibitors, and chemodietary agents with antioxidant properties significantly reduced the CCS and CCS-EVs mediated HIV-1 replication in U1 cells. Altogether, we demonstrate that cervical cancer cells exacerbate HIV-1 replication in differentiated U1 cell line via transferring CYPs and HPV oncoproteins through EVs. We also show that the viral replication occurs via CYP and oxidative stress pathways, and the viral replication is also reduced by chemodietary agents. This study provides important information regarding biological interactions between HPV and HIV-1 via EVs leading to enhanced HIV-1 replication.

A lex naturalis delineates components of a human-specific, adrenal androgen-dependent, p53-mediated 'kill switch' tumor suppression mechanism

We have recently described in this journal our detection of an anthropoid primate-specific, adrenal androgen-dependent, p53-mediated, 'kill switch' tumor suppression mechanism that reached its fullest expression only in humans, as a result of human-specific exposure to polycyclic aromatic hydrocarbons caused by the harnessing of fire - but which has components reaching all the way back to the origin of the primate lineage. We proposed that species-specific mechanisms of tumor suppression are a generalized requirement for vertebrate species to increase in body size or lifespan beyond those of species basal to their lineage or to exploit environmental niches which increase exposure to carcinogenic substances. Using empirical dynamic modeling, we have also reported our detection of a relationship between body size, lifespan, and species-specific mechanism of tumor suppression (and here add carcinogen exposure), such that a change in any one of these variables requires an equilibrating change in one or more of the others in order to maintain lifetime cancer risk at a value of about 4%, as observed in virtually all larger, longer-lived species under natural conditions. Here we show how this relationship, which we refer to as the lex naturalis of vertebrate speciation, elucidates the evolutionary steps underlying an adrenal androgen-dependent, human-specific 'kill switch' tumor suppression mechanism; and further, how it prescribes a solution to 'normalize' lifetime cancer risk in our species from its current aberrant 40% to the 4% that characterized primitive humans. We further argue that this prescription writ by the lex naturalis represents the only tenable strategy for meaningful suppression of the accelerating impact of cancer upon our species.

Increased nasal matrix metalloproteinase-1 and -9 expression in smokers with chronic rhinosinusitis and asthma

A potential mechanism underlying cigarette smoke-induced airway disease is insufficient tissue repair via altered production of matrix metalloproteinases (MMPs). Osteitis is a signature feature of recalcitrant chronic rhinosinusitis (CRS) and often results in revision surgery. The present study aimed to investigate MMP expression in the nasal tissues of asthmatic patients with CRS and any association with cigarette smoking and osteitis. Thirteen smokers with CRS and asthma, 16 non-smokers with CRS and asthma, and seven non-smoker asthmatic patients without CRS were prospectively recruited. The expression of MMPs and associated immunological factors in surgically-obtained nasal tissues was evaluated via real-time PCR and western blotting. Maximal bone thickness of the anterior ethmoid (AE) partition was measured in axial sinus computed tomography (CT) sections. MMP-1 and MMP-9 expression was increased in the nasal tissues of smokers with asthma and CRS via real-time PCR and western blot. Maximal AE partition bone thickness was greater in smokers with CRS and asthma than in non-smokers with CRS and asthma. MMP-1 and MMP-9 levels were correlated with maximal AE bone thickness. Cigarette smoking was associated with the up-regulation of MMP-1 and MMP-9 in the nasal tissues of patients with airway inflammatory diseases, and with AE osteitis, and with therapeutic resistence.

Socio-Economic and Environmental Factors Related to Spatial Differences in Human Non-Tuberculous Mycobacterial Diseases in the Czech Republic

Non-tuberculous mycobacteria (NTM) are ubiquitous environmental bacteria that can induce pulmonary and non-pulmonary diseases in susceptible persons. It is reported that the prevalence of NTM diseases is increasing in developed countries, but this differs by regions and countries. NTM species distribution and the rate of diseases caused by NTM vary widely in the historical territories of Moravia and Silesia (Czech Republic). This epidemiologic study of NTM diseases covers the period 2012–2018, reviews isolates obtained from patients with clinical disease and investigates correlations with related socio-economic and environmental factors. Individual NTM patients were included only once during the studied period and results were presented as incidence rate per year. The most frequently isolated NTM meeting the microbiological and clinical criteria in the study were the Mycobacterium avium-intracellulare complex, followed by Mycobacterium kansasii and Mycobacteriumxenopi. A previously described endemic incidence of M.kansasii in the Karviná district and M.xenopi in the Ostrava district was also observed in this study. The incidence of NTM patients in the whole studied territory was 1.10/100,000 inhabitants (1.33/100,000 in men and 0.88/100,000 in women). The annual incidence of lymphadenitis in children (≤5 years of age) was 2.35/100,000 of the population of children during the 7 year period but increased in the year 2018 to 5.95/100,000. The rate of human tuberculosis in the studied area was 1.97/100,000 inhabitants. The incidence of NTM pulmonary diseases correlated with a lower socio-economic status (r = 0.63) and a higher concentration of benzo[a]pyrene pollution in the air (r = 0.64).

Plasma exosomes exacerbate alcohol- and acetaminophen-induced toxicity via CYP2E1 pathway

Cellular CYP2E1 is well-known to mediate alcohol- (ALC) and acetaminophen- (APAP) induced toxicity in hepatic and extra-hepatic cells. Although exosomes have been gaining importance in understanding mechanism of intra- and inter-cellular communication, the functional role of drug metabolizing cytochrome P450 (CYP) enzymes in human plasma exosomes are yet to be explored. In our previous study, we reported that human plasma-derived exosomes contain substantial level of functional CYP2E1. In the current project, we investigated the potential role of plasma exosomal CYP2E1 in mediating ALC- and APAP-induced toxicity. We treated hepatic and extra-hepatic (monocytic) cells with exosomes ± ALC/APAP. We observed that the plasma exosomes containing CYP2E1 cargo further exacerbate ALC- and APAP-induced toxicity in both hepatic and monocytic cells. Further, both exosomes- and ALC/APAP-induced toxicity was reduced/abolished by a selective inhibitor of CYP2E1 enzyme activity (diallyl ether). However, only ALC-, but not exosome-induced toxicity was reduced/abolished by CYP2E1 siRNA. These findings suggest that ALC/APAP-induced toxicity in the presence of exosomes are mediated, at least in part, by CYP2E1 enzyme. To validate these in vitro findings, we characterized plasma exosomal contents in a binge-drinking animal model and their effect on ALC/APAP-induced toxicity in monocytic cells. Our results showed that ALC exposure caused a significant induction of the plasma exosomal CYP2E1 level in a binge drinking murine model. These exosomes containing increased levels of CYP2E1 caused significant toxicity in monocytic cells compared to exosomes derived from control mice. Overall, our results showed an important role of exosomal CYP2E1 in exacerbating ALC- and APAP-induced toxicity. The study is significant in terms of understanding the role of exosomal CYP2E1 in cell-cell interactions, and their effects on drug-induced toxicity.

Ethyl 2,4-dicarboethoxy pantothenate, a derivative of pantothenic acid, prevents cellular damage initiated by environmental pollutants through Nrf2 activation

BACKGROUND

Recently, environmental pollutants have become a concern not only for respiratory organs but also for skin-related human health, because skin is localized at the border between the human body and the external environment and is easily influenced by environmental pollutants.

OBJECTIVE

Here, we investigated the effects of a novel pantothenic acid (PA) derivative, ethyl 2,4-dicarboethoxy pantothenate (EDCEP), on a diesel particulate extract (DPE) as a representative environmental pollutant that generates reactive oxygen species (ROS) through the activation of aryl hydrocarbon receptor (AHR) signaling.

METHODS

We characterized the effects of PA and EDCEP on normal human epidermal keratinocytes (NHEKs) exposed to DPE or H₂O₂ as a general oxidative stress stimulator. Cell viability and intracellular ROS levels were evaluated using the 3-(4,5-dimethyl-2-thiazoyl)-2,5-diphenyltetrazolium bromide (MTT) assay and the 2',7'-dichlorodihydrofluorescein diacetate (DCFDA) assay, respectively. Further, we investigated the substantial effects and the underlying mechanism of EDCEP, which elicited a reduction of intracellular ROS.

RESULTS

PA and EDCEP restored the decreases of cell viability induced by DPE and also repressed the up-regulation of CYP1A1 mRNA expression induced by DPE. Interestingly, the effects of PA and EDCEP on intracellular ROS levels showed different responses. EDCEP reduced intracellular ROS levels stimulated by DPE or by exposure to H₂O₂. EDCEP suppressed the secretion of tumor necrosis factor (TNF-α) and reduced the level carbonylated proteins in reconstructed human epidermal equivalents topically treated with DPE. EDCEP up-regulated the mRNA expression levels of nuclear factor E2-related factor 2 (Nrf2), γ-glutamyl cysteine synthase (γ-GCS), heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase-1 (NQO1) and in addition, increased intracellular glutathione (GSH) levels.

CONCLUSION

EDCEP reduces cellular damage initiated by environmental pollutants by stimulating the intracellular defense system against ROS through the activation of Nrf2, and by interfering with AHR signaling pathway activation.

Potential neuroprotective role of astroglial exosomes against smoking-induced oxidative stress and HIV-1 replication in the central nervous system

INTRODUCTION

HIV-1-infected smokers are at risk of oxidative damage to neuronal cells in the central nervous system by both HIV-1 and cigarette smoke. Since neurons have a weak antioxidant defense system, they mostly depend on glial cells, particularly astrocytes, for protection against oxidative damage and neurotoxicity. Astrocytes augment the neuronal antioxidant system by supplying cysteine-containing products for glutathione synthesis, antioxidant enzymes such as SOD and catalase, glucose for antioxidant regeneration via the pentose-phosphate pathway, and by recycling of ascorbic acid. Areas covered: The transport of antioxidants and energy substrates from astrocytes to neurons could possibly occur via extracellular nanovesicles called exosomes. This review highlights the neuroprotective potential of exosomes derived from astrocytes against smoking-induced oxidative stress, HIV-1 replication, and subsequent neurotoxicity observed in HIV-1-positive smokers. Expert opinion: During stress conditions, the antioxidants released from astrocytes either via extracellular fluid or exosomes to neurons may not be sufficient to provide neuroprotection. Therefore, we put forward a novel strategy to combat oxidative stress in the central nervous system, using synthetically developed exosomes loaded with antioxidants such as glutathione and the anti-aging protein Klotho.

Ambient particulate matter activates the aryl hydrocarbon receptor in dendritic cells and enhances Th17 polarization

The objective of this study was to explore the role of the aryl hydrocarbon receptor (AhR) in ambient particulate matter (PM)-mediated activation of dendritic cells (DCs) and Th17-immune responses in vitro. To assess the potential role of the AhR in PM-mediated activation of DCs, co-stimulation, and cytokine expression, bone marrow (BM)-derived macrophages and DCs from C57BL/6 wildtype or AhR knockout (AhR-/-) mice were treated with PM. Th17 differentiation was assessed via co-cultures of wildtype or AhR-/- BMDCs with autologous naive T cells. PM2.5 significantly induced AhR DNA binding activity to dioxin responsive elements (DRE) and expression of the AhR repressor (AhRR), cytochrome P450 (CYP) 1A1, and CYP1B1, indicating activation of the AhR. In activated (OVA sensitized) BMDCs, PM2.5 induced interleukin (IL)-1β, CD80, CD86, and MHC class II, suggesting enhanced DC activation, co-stimulation, and antigen presentation; responses that were abolished in AhR deficient DCs. DC-T cell co-cultures treated with PM and lipopolysaccharide (LPS) led to elevated IL-17A and IL-22 expression at the mRNA level, which is mediated by the AhR. PM-treated DCs were essential in endowing T cells with a Th17-phenotype, which was associated with enhanced expression of MHC class II and cyclooxygenase (COX)-2. In conclusion, PM enhances DC activation that primes naive T cell differentiation towards a Th17-like phenotype in an AhR-dependent manner.

Benzo(a)pyrene in Cigarette Smoke Enhances HIV-1 Replication through NF-κB Activation via CYP-Mediated Oxidative Stress Pathway

Smoking aggravates HIV-1 pathogenesis and leads to decreased responses to antiretroviral therapy. In this study, we aim to find a molecular mechanism that would explain smoking-induced HIV-1 replication. Benzo(a)pyrene (BaP), a major carcinogen in cigarette, requires metabolic activation through cytochrome P450s (CYPs) to exert its toxic effects. We hypothesized that CYP-mediated BaP metabolism generates reactive oxygen species (ROS), and the resultant oxidative stress aggravates HIV-1 replication. As expected, we observed ~3 to 4-fold increase in HIV-1 replication in U1 cells and human primary macrophages after chronic BaP exposure. We also observed ~30-fold increase in the expression of CYP1A1 at mRNA level, ~2.5-fold increase in its enzymatic activity as well as elevated ROS and cytotoxicity in U1 cells. The knock-down of the CYP1A1 gene using siRNA and treatment with selective CYP inhibitors and antioxidants significantly reduced HIV-1 replication. Further, we observed a nuclear translocation of NF-κB subunits (p50 and p65) after chronic BaP exposure, which was reduced by treatment with siRNA and antioxidants/CYP inhibitors. Suppression of NF-κB pathway using specific NF-κB inhibitors also significantly reduced HIV-1 replication. Altogether, our results suggest that BaP enhances HIV-1 replication in macrophages by a CYP-mediated oxidative stress pathway followed by the NF-κB pathway.

Monocyte-derived exosomes upon exposure to cigarette smoke condensate alter their characteristics and show protective effect against cytotoxicity and HIV-1 replication

Smoking is known to exacerbate HIV-1 pathogenesis, especially in monocytes, through the oxidative stress pathway. Exosomes are known to alter HIV-1 pathogenesis through inter-cellular communication. However, the role of exosomes in smoking-mediated HIV-1 pathogenesis is unknown. In this study, we investigated the effect of cigarette smoke condensate (CSC) on the characteristics of monocyte-derived exosomes and their influence on HIV-1 replication. Initially, we demonstrated that CSC reduced total protein and antioxidant capacity in exosomes derived from HIV-1-infected and uninfected macrophages. The exosomes from CSC-treated uninfected cells showed a protective effect against cytotoxicity and viral replication in HIV-1-infected macrophages. However, exosomes derived from HIV-1-infected cells lost their protective capacity. The results suggest that the exosomal defense is likely to be more effective during the early phase of HIV-1 infection and diminishes at the latter phase. Furthermore, we showed CSC-mediated upregulation of catalase in exosomes from uninfected cells, with a decrease in the levels of catalase and PRDX6 in exosomes derived from HIV-1-infected cells. These results suggest a potential role of antioxidant enzymes, which are differentially packaged into CSC-exposed HIV-1-infected and uninfected cell-derived exosomes, on HIV-1 replication of recipient cells. Overall, our study suggests a novel role of exosomes in tobacco-mediated HIV-1 pathogenesis.

Novel elvitegravir nanoformulation approach to suppress the viral load in HIV-infected macrophages

Purpose

Monocytes serve as sanctuary sites for HIV-1 from which virus is difficult to be eliminated. Therefore, an effective viral suppression in monocytes is critical for effective antiretroviral therapy (ART). This study focuses on a new strategy using nanoformulation to optimize the efficacy of ART drugs in HIV-infected monocytes.

Methods

Poly(lactic-co-glycolic acid) (PLGA)-based elvitegravir nanoparticles (PLGA-EVG) were prepared by nano-precipitation technique. The physicochemical properties of PLGA-EVG were characterized using transmission electron microscopy, dynamic light scattering, and Fourier-transform infrared spectroscopy. Cellular uptake study was performed by fluorescence microscopy and flow cytometry. All in vitro experiments were performed by using HIV-infected monocytic cell lines U1 and HIV-infected primary macrophages. Elvitegravir quantification was performed using LC-MS/MS. HIV viral replication was assessed by using p24 ELISA.

Results

We developed a PLGA-EVG nanoparticle formulation with particle size of ~ 47 nm from transmission electron microscopy and zeta potential of ~ 6.74 mV from dynamic light scattering. These nanoparticles demonstrated a time- and concentration-dependent uptakes in monocytes. PLGA-EVG formulation showed a ~ 2 times higher intracellular internalization of EVG than control group (EVG alone). PLGA-EVG nanoparticles also demonstrated superior viral suppression over control for a prolonged period of time.

Conclusions

PLGA-based EVG nanoformulation increased the intracellular uptake of EVG, as well as enhanced viral suppression in HIV-infected macrophages, suggesting its potential for improved HIV treatment in monocytic cells.

Transformation of liver cells by 3-methylcholanthrene potentiates oxidative stress via the downregulation of glutathione synthesis

Polycyclic aromatic hydrocarbons (PAHs) are widespread contaminants resulting from the incomplete combustion of organic materials in the environment. The primary concern for the hazardous effect of PAHs is their ability to activate the pathway linked to the aryl hydrocarbon receptor (AhR) and lead to carcinogenesis. While previous research has demonstrated that oxidative stress plays a key role in the AhR-dependent toxic response, the effect of PAHs on the biosynthesis of glutathione (GSH), which is a powerful endogenous antioxidant, has not been extensively investigated. In the present study, we utilized a global metabolomic approach, via high resolution magic angle spinning nuclear magnetic resonance spectroscopy, and identified significant metabolome differences between non-tumorigenic liver cells (BNL CL.2; CL2) and transformed liver cells (BNL 1MEA. 7R.1; 1MEA) chronically exposed to 3-methylcholanthrene (3MC), a well‑known carcinogenic PAH. A significant change that was observed, was a lower GSH level in 1MEA cells compared with that in CL2 cells. This was contrasted by increased levels of precursor metabolites for GSH synthesis, such as S-adenosylmethionine and cysteine. These changes were accompanied by a significantly reduced expression of γ-glutamylcysteine ligase (GCL), known to be the rate‑limiting step of GSH synthesis. Furthermore, the protein level of cysteine dioxygenase was downregulated; however, the concentration of taurine was unaltered. Therefore, the present study demonstrated that cells transformed by chronic exposure to 3MC exhibited inhibition of GSH biosynthesis by suppression of GCL protein expression and reduction of cysteine availability, which may subsequently render cells vulnerable to oxidative stress.