Diesel particulate matter2.5 promotes epithelial-mesenchymal transition of human retinal pigment epithelial cells via generation of reactive oxygen species

MicroRNA-145-5p Regulates the Epithelial-Mesenchymal Transition in Nasal Polyps by Targeting Smad3

OBJECTIVES

The annual prevalence of chronic rhinosinusitis (CRS) is increasing, and the lack of effective treatments imposes a substantial burden on both patients and society. The formation of nasal polyps in patients with CRS is closely related to tissue remodeling, which is largely driven by the epithelial-mesenchymal transition (EMT). MicroRNA (miRNA) plays a pivotal role in the pathogenesis of numerous diseases through the miRNA-mRNA regulatory network; however, the specific mechanism of the miRNAs involved in the formation of nasal polyps remains unclear.

METHODS

The expression of EMT markers and Smad3 were detected using western blots, quantitative real-time polymerase chain reaction, and immunohistochemical and immunofluorescence staining. Differentially expressed genes in nasal polyps and normal tissues were screened through the Gene Expression Omnibus database. To predict the target genes of miR-145-5p, three different miRNA target prediction databases were used. The migratory ability of cells was evaluated using cell migration assay and wound healing assays.

RESULTS

miR-145-5p was associated with the EMT process and was significantly downregulated in nasal polyp tissues. In vitro experiments revealed that the downregulation of miR-145-5p promoted EMT. Conversely, increasing miR-145-5p levels reversed the EMT induced by transforming growth factor-β1. Bioinformatics analysis suggested that miR-145-5p targets Smad3. Subsequent experiments confirmed that miR-145-5p inhibits Smad3 expression.

CONCLUSION

Overall, miR-145-5p is a promising target to inhibit nasal polyp formation, and the findings of this study provide a theoretical basis for nanoparticle-mediated miR-145-5p delivery for the treatment of nasal polyps.

PDE12 disrupts mitochondrial oxidative phosphorylation and mediates mitochondrial dysfunction to induce oral mucosal epithelial barrier damage in oral submucous fibrosis

Oral submucous fibrosis (OSF) is a chronic oral mucosal disease. The pathological changes of OSF include epithelial damage and subepithelial matrix fibrosis. This study aimed to reveal the epithelial injury mechanism of OSF. A histopathological method was used to analyze oral mucosal tissue from OSF patients and OSF rats. The expression of PDE12 in the oral epithelium was analyzed by immunohistochemistry. The epithelial-mesenchymal transition (EMT) and tight junction proteins in arecoline-treated HOKs were explored by western blotting. Epithelial leakage was assessed by transepithelial electrical resistance and lucifer yellow permeability. The expression of PDE12 and the mitochondrial morphology, mitochondrial permeability transition pore opening, mitochondrial membrane potential, and mitochondrial reactive oxygen species (mtROS) were evaluated in arecoline-induced HOKs. Oxidative phosphorylation (OXPHOS) complexes and ATP content were also explored in HOKs. The results showed significant overexpression of PDE12 in oral mucosal tissue from OSF patients and rats. PDE12 was also overexpressed and aggregated in mitochondria in arecoline-induced HOKs, resulting in dysfunction of OXPHOS and impaired mitochondrial function. An EMT, disruption of tight junctions with epithelial leakage, and extracellular matrix remodeling were also observed. PDE12 overexpression induced by PDE12 plasmid transfection enhanced the mtROS level and interfered with occludin protein localization in HOKs. Interestingly, knockdown of PDE12 clearly ameliorated arecoline-induced mitochondrial dysfunction and epithelial barrier dysfunction in HOKs. Therefore, we concluded that overexpression of PDE12 impaired mitochondrial OXPHOS and mitochondrial function and subsequently impaired epithelial barrier function, ultimately leading to OSF. We suggest that PDE12 may be a new potential target against OSF.

A comprehensive review on the emerging role of long non-coding RNAs in the regulation of NF-κB signaling in inflammatory lung diseases

Public health globally faces significant risks from conditions like acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD), and various inflammatory lung disorders. The NF-κB signaling system partially controls lung inflammation, immunological responses, and remodeling. Non-coding RNAs (lncRNAs) are crucial in regulating gene expression. They are increasingly recognized for their involvement in NF-κB signaling and the development of inflammatory lung diseases. Disruption of lncRNA-NF-κB interactions is a potential cause and resolution factor for inflammatory respiratory conditions. This study explores the therapeutic potential of targeting lncRNAs and NF-κB signaling to alleviate inflammation and restore lung function. Understanding the intricate relationship between lncRNAs and NF-κB signaling could offer novel insights into disease mechanisms and identify therapeutic targets. Regulation of lncRNAs and NF-κB signaling holds promise as an effective approach for managing inflammatory lung disorders. This review aims to comprehensively analyze the interaction between lncRNAs and the NF-κB signaling pathway in the context of inflammatory lung diseases. It investigates the functional roles of lncRNAs in modulating NF-κB activity and the resulting inflammatory responses in lung cells, focusing on molecular mechanisms involving upstream regulators, inhibitory proteins, and downstream effectors.

Acute exposure to diesel particulate matter promotes collective cell migration in thyroid cancer cells

Several ecological studies suggest that ambient air pollution is associated with the occurrence of thyroid cancer. In this study, we used certified diesel particulate matter as a proxy for fine particulate matter. Human thyroid cancer cell lines 8505C and TPC-1 were incubated with different concentrations of NIST1650b for 5 days and subjected to functional assays. We found that NIST1650b treatment did not affect short-term cell growth but reduced colony formation at high concentrations. Notably, NIST1650b-treated cells showed altered morphology toward cluster coalescence following treatment. Wound healing assays revealed that leading-edge cells formed protruding tips while maintaining cell-cell adhesion, and a significantly higher ratio of wound closure following treatment at 10 μg/mL was seen in both cell lines. A weak stimulatory effect on transwell cell migration was observed in 8505C cells. Taken together, our results suggest that fine particulate matter induced a coherent phenotype accompanied by augmented collective cell migration in thyroid cancer cells.

Molecular pathogenesis of subretinal fibrosis in neovascular AMD focusing on epithelial-mesenchymal transformation of retinal pigment epithelium

Age-related macular degeneration (AMD) is a leading cause of vision loss among elderly people in developed countries. Neovascular AMD (nAMD) accounts for more than 90% of AMD-related vision loss. At present, intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) is widely used as the first-line therapy to decrease the choroidal and retinal neovascularizations, and thus to improve or maintain the visual acuity of the patients with nAMD. However, about 1/3 patients still progress to irreversible visual impairment due to subretinal fibrosis even with adequate anti-VEGF treatment. Extensive literatures support the critical role of epithelial-mesenchymal transformation (EMT) of retinal pigment epithelium (RPE) in the pathogenesis of subretinal fibrosis in nAMD, but the underlying mechanisms still remain largely unknown. This review summarized the molecular pathogenesis of subretinal fibrosis in nAMD, especially focusing on the transforming growth factor-β (TGF-β)-induced EMT pathways. It was also discussed how these pathways crosstalk and respond to signals from the microenvironment to mediate EMT and contribute to the progression of nAMD-related subretinal fibrosis. Targeting EMT signaling pathways might provide a promising and effective therapeutic strategy to treat subretinal fibrosis secondary to nAMD.

A Review of Ambient Air Pollution as a Risk Factor for Posterior Segment Ocular Diseases

PURPOSE

To review the most recent evidence on the association of ambient air pollution with posterior segment ocular diseases.

METHODS

A search of the most recently published medical literature was performed in PubMed and Google Scholar on 10 December 2022. Articles published between 2018 and December 2022 were included in this rapid review. Studies that evaluated the association between ambient air pollutants (nitrogen dioxide (NO₂), carbon monoxide (CO), sulfur dioxide (SO₂), ozone (O₃), particulate matters (PM_s), total hydrocarbons (THC), nonmethane hydrocarbons (NMHC), benzene), and ocular posterior segment diseases (glaucoma, age-related macular degeneration (AMD), and retinal vascular diseases) were included.

RESULTS

Nineteen research articles met the inclusion criteria. Significant associations were found between PM_2.5 and glaucoma, including primary open angle, primary angle closure, and normal tension glaucoma. An increased risk of AMD was linked to increased exposure to PM_2.5, NO₂, and CO. Single studies suggested that increased exposure to PM_2.5 and PM₁₀ is associated with diabetic retinopathy; THC and NMHC increased the risk of retinal vein occlusion; and CO, NO₂, and PM₁₀ are linked to an increased risk of central retinal artery occlusion.

CONCLUSIONS

There is increasing evidence that toxic air pollutants have an impact on posterior segment ocular diseases, hence determining it as a potential modifiable risk factor for visual impairment.

Exogenous 8-Hydroxydeoxyguanosine Attenuates PM2.5-Induced Inflammation in Human Bronchial Epithelial Cells by Decreasing NLRP3 Inflammasome Activation

Particulate matter 2.5 (PM_2.5) induces lung injury by increasing the generation of reactive oxygen species (ROS) and inflammation. ROS aggravates NLRP3 inflammasome activation, which activates caspase-1, IL-1β, and IL-18 and induces pyroptosis; these factors propagate inflammation. In contrast, treatment with exogenous 8-hydroxydeoxyguanosine (8-OHdG) decreases RAC1 activity and eventually decreases dinucleotide phosphate oxidase (NOX) and ROS generation. To establish modalities that would mitigate PM_2.5-induced lung injury, we evaluated whether 8-OHdG decreased PM_2.5-induced ROS generation and NLRP3 inflammasome activation in BEAS-2B cells. CCK-8 and lactate dehydrogenase assays were used to determine the treatment concentration. Fluorescence intensity, Western blotting, enzyme-linked immunosorbent assay, and immunoblotting assays were also performed. Treatment with 80 μg/mL PM_2.5 increased ROS generation, RAC1 activity, NOX1 expression, NLRP3 inflammasome (NLRP3, ASC, and caspase-1) activity, and IL-1β and IL-18 levels in cells; treatment with 10 μg/mL 8-OHdG significantly attenuated these effects. Furthermore, similar results, such as reduced expression of NOX1, NLRP3, ASC, and caspase-1, were observed in PM_2.5-treated BEAS-2B cells when treated with an RAC1 inhibitor. These results show that 8-OHdG mitigates ROS generation and NLRP3 inflammation by inhibiting RAC1 activity and NOX1 expression in respiratory cells exposed to PM_2.5.

Particulate Matter Elevates Ocular Inflammation and Endoplasmic Reticulum Stress in Human Retinal Pigmented Epithelium Cells

Because of their exposure to air, eyes can come into contact with air pollutants such as particulate matter (PM), which may cause severe ocular pathologies. Prolonged ocular PM exposure may increase inflammation and endoplasmic reticulum stress in the retina. Herein, we investigated whether PM exposure induces ocular inflammation and endoplasmic reticulum (ER) stress-related cellular responses in human retinal epithelium-19 (ARPE-19) cells. To understand how PM promotes ocular inflammation, we monitored the activation of the mitogen-activated protein kinase (MAPK)/nuclear factor kappa beta (NFκB) axis and the expression of key inflammatory mRNAs. We also measured the upregulation of signature components for the ER-related unfolded protein response (UPR) pathways, as well as intracellular calcium ([Ca²⁺]_i) levels, as readouts for ER stress induction following PM exposure. Ocular PM exposure significantly elevated the expression of multiple cytokine mRNAs and increased phosphorylation levels of NFκB-MAPK axis in a PM dose-dependent manner. Moreover, incubation with PM significantly increased [Ca²⁺]_i levels and the expression of UPR-related proteins, which indicated ER stress resulting from cell hypoxia, and upregulation of hypoxic adaptation mechanisms such as the ER-associated UPR pathways. Our study demonstrated that ocular PM exposure increased inflammation in ARPE-19 cells, by activating the MAPK/NFκB axis and cytokine mRNA expression, while also inducing ER stress and stress adaptation responses. These findings may provide helpful insight into clinical and non-clinical research examining the role of PM exposure in ocular pathophysiology and delineating its underlying molecular mechanisms.

Lnc-IL7R alleviates PM2.5-mediated cellular senescence and apoptosis through EZH2 recruitment in chronic obstructive pulmonary disease

BACKGROUND

Long-term exposure to PM_2.5 (particulate matter with an aerodynamic diameter of ≤ 2.5 μm) is associated with pulmonary injury and emphysema in patients with chronic obstructive pulmonary disease (COPD). We investigated mechanisms through which the long noncoding RNA lnc-IL7R contributes to cellular damage by inducing oxidative stress in COPD patients exposed to PM_2.5.

METHODS

Associations of serum lnc-IL7R levels with lung function, emphysema, and previous PM_2.5 exposure in COPD patients were analyzed. Reactive oxygen species and lnc-IL7R levels were measured in PM_2.5-treated cells. The levels of lnc-IL7R and cellular senescence-associated genes, namely p16^INK4a and p21^CIP1/WAF1, were determined through lung tissue section staining. The effects of p16^INK4a or p21^CIP1/WAF1 regulation were examined by performing lnc-IL7R overexpression and knockdown assays. The functions of lnc-IL7R-mediated cell proliferation, cell cycle, senescence, colony formation, and apoptosis were examined in cells treated with PM_2.5. Chromatin immunoprecipitation assays were conducted to investigate the epigenetic regulation of p21^CIP1/WAF1.

RESULTS

Lnc-IL7R levels decreased in COPD patients and were negatively correlated with emphysema or PM_2.5 exposure. Lnc-IL7R levels were upregulated in normal lung epithelial cells but not in COPD cells exposed to PM_2.5. Lower lnc-IL7R expression in PM_2.5-treated cells induced p16^INK4a and p21^CIP1/WAF1 expression by increasing oxidative stress. Higher lnc-IL7R expression protected against cellular senescence and apoptosis, whereas lower lnc-IL7R expression augmented injury in PM_2.5-treated cells. Lnc-IL7R and the enhancer of zeste homolog 2 (EZH2) synergistically suppressed p21^CIP1/WAF1 expression through epigenetic modulation.

CONCLUSION

Lnc-IL7R attenuates PM_2.5-mediated p21^CIP1/WAF1 expression through EZH2 recruitment, and its dysfunction may augment cellular injury in COPD.

Ambient particulate matter exposure causes visual dysfunction and retinal neuronal degeneration

PM_2.5 pollution is related to neurotoxic and vascular effects in eye diseases such as glaucoma. This study investigates the adverse effects of PM_2.5 exposure on visual function and retinal neurons. A versatile aerosol concentration enrichment system was used to expose mice to either control air or PM_2.5 polluted air. Six months after PM_2.5 exposure, visual function was measured by electroretinography (ERG). Hematoxylin and eosin staining and immunofluorescence staining were used for histopathological analysis. Protein markers of apoptosis, astrocytic reactivity, inflammatory cytokines, lipid peroxidation, protein nitration and DNA damage response were quantified with ELISA, western blot or detected using immunofluorescence and immunohistochemistry. After six months of exposure, PM_2.5-exposed mice responded poorly to light stimuli compared with those exposed to the control air. PM_2.5 exposure caused retinal thinning and reduction in the expression of retinal ganglion cell-selective marker RNA-binding protein with multiple splicing (RBPMS). Further, positive TUNEL staining was observed in the inner nucleus and outer nuclear layers of the retinae after exposure to PM_2.5, which was accompanied by the activation of apoptosis signaling molecules p53, caspase-3 and Bax. PM_2.5 induced the release of inflammatory cytokines including tumor necrosis factor-α and cleaved interleukin-1β. Furthermore, increased levels of 8-OHdG and γ-H2AX in the mouse retinea were indicative of DNA single and double strand breaks by PM_2.5 exposure, which activated PARP-1 mediated DNA damage and repair. In conclusion, this study demonstrates sub-chronic systemic exposure to concentrated PM_2.5 causes visual dysfunction and retinal neuronal degeneration. DATA AVAILABILITY: The datasets during and/or analyzed during the current study available from the corresponding author on reasonable request.

CD82 attenuates TGF-β1-mediated epithelial-mesenchymal transition by blocking smad-dependent signaling in ARPE-19 cells

In retinal pigment epithelial (RPE) cells, transforming growth factor-beta (TGF-β) plays a critical role in epithelial-mesenchymal transition (EMT), which contributes to various fibrotic retinal disorders. In the present study, we investigated the effect of recombinant human cluster of differentiation 82 (rhCD82), a tumor metastasis suppressor, on TGF-β-induced EMT in the human RPE cell line APRE-19. The results show that TGF-β1 significantly enhanced cell migration, invasion and the expression of EMT-mediate factors in ARPE-19 cells. However, rhCD82 markedly inhibited cell mobility and the expression of epithelial marker, zonula occludens-1, as well as increased the expression of mesenchymal markers, such as vimentin and α-smooth muscle actin in TGF-β1-treated APRE-19 cells. In addition, TGF-β1 upregulated the phosphorylation of Smad, extracellular signal regulated kinase (ERK) and glycogen synthase kinase-3β (GSK-3β), but only phosphorylation of Smad was suppressed by rhCD82. Noteworthy, rhCD82 greatly suppressed the expression of TGF-β receptor I (TGFRI), TGFRII and integrins in TGF-β1-treated APRE-19 cells. In particular, the result of molecular docking analysis and structural modeling show that rhCD82 partially interacts with the TGF-β1 binding sites of TGFRI, TGFRII, integrin β1 and integrin αv. Taken together, this finding suggested that rhCD82 suppressed TGF-β1-induced EMT of RPE by blocking of Smad-dependent pathway, which is caused by rhCD82 interaction with TGFRs and integrins, suggesting new insight into CD82 as a potential therapeutic strategy in fibrotic retinal disorders.

Polystyrene nanoplastics exacerbate lipopolysaccharide-induced myocardial fibrosis and autophagy in mice via ROS/TGF-β1/Smad

Polystyrene nanoplastics (PS NPs) contamination is a serious problem for human and animal health. Excessive exposure to PS NPs can affect the structure and function of the heart. And lipopolysaccharide (LPS) induces myocardial damage, leading to myocardial fibrosis (MF). To investigate whether PS NPs exacerbate LPS-induced myocardial autophagy and fibrosis, we established in vivo and in vitro models of PS NPs/LPS exposure alone and in combination. We found that PS NPs/LPS exposure disrupts myocardial structure, significantly increases reactive oxygen species (ROS), triggers oxidative stress, promotes TGF-β1/Smad pathway activation, and leads to elevated levels of fibrotic proteins and collagen. Meanwhile, activation of AMPK/mTOR/ULK1 signaling pathway induced autophagy onset, and combined exposure of PS NPs/LPS exacerbated MF and autophagy. H9C2 cells were used for in vitro experiments, and the experimental results showed that the addition of TGF-β receptor inhibitor LY2109761 to the exposed group not only inhibited the upregulation of fibrotic genes but also effectively reduced the expression of autophagic signals, indicating that combined exposure of PS NPs and LPS mediates and regulates cardiac autophagy through TGF-β1. The above results suggest that PS NPs exacerbate LPS-induced MF and autophagy in mice via ROS/TGF-β1/Smad. Our study provides some new evidence to clarify the potential mechanisms of PS NPs-induced cardiotoxicity.

Particulate matter 2.5 promotes inflammation and cellular dysfunction via reactive oxygen species/p38 MAPK pathway in primary rat corneal epithelial cells

PURPOSE

Numerous studies have linked particulate matter 2.5 (PM_2.5) to ocular surface diseases, but few studies have been conducted on the biological effect of PM_2.5 on the cornea. The objective of the present study was to evaluate the harmful effect of PM2.5 on primary rat corneal epithelial cells (RCECs) in vitro and identify the toxic mechanism involved.

MATERIALS AND METHODS

Primary cultured RCECs were characterized by pan-cytokeratin (CK) staining. In PM2.5-exposed RCECs, cell viability, microarray gene expression, inflammatory cytokine levels, mitochondrial damage, DNA double-strand break and signaling pathway were investigated.

RESULTS

Exposure to PM_2.5 induced cytotoxicity and morphological changes in RCECs. In addition, PM_2.5 markedly up-regulated pro-inflammatory mediators but down-regulated the wound healing-related transforming growth factor-β. Furthermore, PM_2.5 promoted mitochondrial reactive oxygen species (ROS) production and mediated cellular damage to mitochondria and DNA, whereas these cellular alterations induced by PM_2.5 were markedly suppressed by a potential ROS scavenger. Noteworthy, removal of ROS selectively down-regulated the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and the activation of the nuclear factor-κB (NF-κB) p65 in PM_2.5-stimulated cells. Additionally, SB203580, a p38 MAPK inhibitor, markedly suppressed these PM_2.5-mediated cellular dysfunctions.

CONCLUSIONS

Taken together, our findings show that PM_2.5 can promote the ROS/p38 MAPK/NF-κB signaling pathway and lead to mitochondrial damage and DNA double-strand break, which is ultimately caused inflammation and cytotoxicity in RCECs. These findings indicate that the ROS/p38 MAPK/NF-κB signaling pathway is one mechanism involved in PM_2.5-induced ocular surface disorders.

Particulate matter 2.5 exposure induces epithelial-mesenchymal transition via PI3K/AKT/mTOR pathway in human retinal pigment epithelial ARPE-19 cells

Exposure to particulate matter 2.5 (PM2.5) has been linked to ocular surface diseases, yet knowledge of the molecular mechanism impacted on retina pathogenesis is limited. Therefore, the purpose of this study was to explore the effects and involved factors of PM2.5 exposure in human retinal pigment epithelial APRE-19 cells. Our data revealed a decreased cell viability and an increased migratory ability in APRE-19 cells after PM2.5 stimulation. The MMP-2 and MMP-9 protein levels were markedly increased while the MMPs regulators TIMP-1 and TIMP-2 were significantly reduced in PM2.5-exposed APRE-19 cells. PM2.5 also increased pro-MMP-2 expression in the cell culture supernatants. Additionally, PM2.5 promoted the EMT markers through the activation of PI3K/AKT/mTOR pathway. Moreover, the ICAM-1 production was also remarkably increased by PM2.5 but reduced by PI3K/AKT inhibitor LY294002 in APRE-19 cells. Taken together, these results suggest that PM2.5 promotes EMT in a PI3K/AKT/mTOR-dependent manner in the retinal pigment epithelium.

Epithelial 3D-spheroids as a tool to study air pollutant-induced lung pathology

Cigarette smoke (CS) and air pollutants (AP) activate pathological processes in bronchial epithelial cells resulting in lung function decline which severely impacts human health. Knowledge about the molecular mechanism(s) by which CS and AP induce pathology is limited. Our previous studies in 2D cultures of human bronchial epithelial (BEAS-2B) cells showed that CS exposure activates transforming growth factor-β1 (TGF-β1) release and signaling. Furthermore, CS exposure reduced the expression of E-cadherin, which was prevented by applying a TGF-β1 neutralizing antibody. Exposure of BEAS-2B cells cultured in 2D to diesel exhaust particles (DEP) increased TGF-β1 protein expression and reduced the expression of epithelial cell markers, whereas mesenchymal markers are upregulated. Conventional 2D cell culture may, however, not fully reflect the physiology of bronchial epithelial cells in vivo. To simulate the in vivo situation more closely we cultured the bronchial epithelial cells in a 3D environment in the current study. Treatment of epithelial spheroids with TGF-β resulted in reduced E-cadherin and increased collagen I expression, indicating the activation of epithelial-to-mesenchymal transition (EMT). Similarly, exposure of spheroids to DEP induced and EMT-like phenotype. Collectively, our data indicate AP induces an EMT-like phenotype of BEAS-2B cells in 3D spheroid cultures. This opens new avenues for drug development for the treatment of lung diseases induced by AP. The 3D spheroid cell culture is a novel, innovative and physiologically relevant model for culturing a variety of cells. It is a versatile tool for both high-throughput studies and for identifying molecular mechanisms involved in bronchial epithelial cell (patho)physiology.

Blood-retina barrier dysfunction in experimental autoimmune uveitis: the pathogenesis and therapeutic targets

Experimental autoimmune uveitis (EAU), an animal model of human uveitis, is characterized by infiltration of autoimmune T cells in the uvea as well as in the retina of susceptible animals. EAU is induced by the immunization of uveitogenic antigens, including either retinal soluble-antigen or interphotoreceptor retinoid-binding proteins, in Lewis rats. The pathogenesis of EAU in rats involves the proliferation of autoimmune T cells in peripheral lymphoid tissues and breakdown of the blood-retinal barrier, primarily in the uvea and retina, finally inducing visual dysfunction. In this review, we describe recent EAU studies to facilitate the design of a therapeutic strategy through the interruption of uveitogenic factors during the course of EAU, which will be helpful for controlling human uveitis.

Oxidative stress activates Ryr2-Ca2+ and apoptosis to promote PM2.5-induced heart injury of hyperlipidemia mice

The increased cases of hyperlipemia in China and the crucial role of PM_2.5 in inducing and promoting cardiovascular diseases have attracting more and more researchers' attention. However, the effects and mechanisms of PM_2.5 on cardiovascular system of hyperlipidemia people are still unclear. In this study, hyperlipidemia mice model was established by high-fat diet. Then we exposed these mice to PM_2.5 or saline to explore the underling mechanism of cardiac injury in hyperlipidemia mice. The hyperlipemia mice are more susceptible to heart damage caused by PM_2.5 exposure. The participation of oxidative stress, cell apoptosis and Ca²⁺ related mechanism could be observed in this model. After NAC (N-acetyl-L-cysteine) treatment, the oxidative stress level induced by PM_2.5 exposure significantly decreased in hyperlipemia mice. NAC effectively alleviated cardiac injury, improved the imbalance of calcium and attenuated apoptosis induced by PM_2.5 exposure in hyperlipemia mice. The strong oxidative stress in hyperlipemia mice could lead to calcium homeostasis imbalance and activation of apoptosis-related pathways. This mechanism of PM_2.5-induced myocardial injury was also verified in vitro. In our present study, we demonstrated the contribution of the PM_2.5-ROS-Ryr2-Ca²⁺ axis in PM_2.5-induced heart injury of hyperlipidemia mice, offering a potential therapeutical target for related pathology.

The Adverse Effects of Air Pollution on the Eye: A Review

Air pollution is inevitably the result of human civilization, industrialization, and globalization. It is composed of a mixture of gases and particles at harmful levels. Particulate matter (PM), nitrogen oxides (NOx), and carbon dioxides (CO₂) are mainly generated from vehicle emissions and fuel consumption and are the main materials causing outdoor air pollution. Exposure to polluted outdoor air has been proven to be harmful to human eyes. On the other hand, indoor air pollution from environmental tobacco smoking, heating, cooking, or poor indoor ventilation is also related to several eye diseases, including conjunctivitis, glaucoma, cataracts, and age-related macular degeneration (AMD). In the past 30 years, no updated review has provided an overview of the impact of air pollution on the eye. We reviewed reports on air pollution and eye diseases in the last three decades in the PubMed database, Medline databases, and Google Scholar and discussed the effect of various outdoor and indoor pollutants on human eyes.

PM2.5 induces inflammatory responses via oxidative stress-mediated mitophagy in human bronchial epithelial cells

BACKGROUND

Fine particulate matter (PM_2.5) is a ubiquitous air pollutant, and it has been reported to be closely associated with lung inflammatory injury. In this study, the potential molecular mechanisms underlying PM_2.5-induced cellular inflammation in human bronchial epithelial (BEAS-2B) cells were investigated.

MATERIALS AND METHODS

Ambient PM_2.5 particulates from Suzhou, China, were collected and re-suspended in ultrapure water. Cellular damages, characterized by oxidative stress, mitochondrial injury, and inflammatory cytokine production, were determined in 24 h PM_2.5-treated BEAS-2B cells with or without 3-methyladenine (3-MA; autophagy inhibitor) pretreatment. Biomarkers related to oxidative damage, inflammatory injury and autophagy signaling pathways were also measured.

RESULTS

Uptake of PM_2.5 in BEAS-2B cells induced cellular oxidative damage, mitochondrial injury, and inflammatory responses as indicated by a significant decrease in GSH/GSSG ratio, increased MDA content, dilated mitochondria with loss and rupture of crista, and production of inflammatory cytokines. Activation of Nrf-2/TXNIP-mediated NF-κB and Bnip3L/NIX-dependent mitophagy signaling pathways, as well as accumulation of autophagosomes and autolysosomes, were also observed. A 6 h pretreatment of 3-MA increased PM_2.5-induced oxidative damage and cellular inflammation as indicated by increasing protein levels of HO-1, TXNIP, Bnip3L/NIX and IL-8 gene expression.

CONCLUSIONS

PM_2.5 induced cellular inflammatory injury by oxidative stress, mitochondrial dysfunction, and mitophagy initiation. Although induction of Bnip3L/NIX-mediated mitophagy in BEAS-2B cells appeared to confer protection in response to PM_2.5, dysfunction of autophagic flux may be a critical contributor to defective mitophagy and cellular inflammatory response.

PM2.5 activated NLRP3 inflammasome and IL-1β release in MH-S cells by facilitating autophagy via activating Wnt5a

Particulate matter 2.5 (PM2.5)-induced pulmonary inflammation is an important issue worldwide. NLRP3 inflammasome activation has been found to be involved in pulmonary inflammation development. However, whether PM2.5 induces pulmonary inflammation by activating the NLRP3 inflammasome has not yet been fully elucidated. This study researched whether PM2.5 induces the NLRP3 inflammasomes activation to trigger pulmonary inflammation.

Mice and MH-S cells were exposed to PM2.5, BOX5, and Rapamycin. Hematoxylin and eosin staining was performed on the lung tissues of mice. M1 macrophage marker CD80 expression in the lung tissues of mice and LC3B expression in MH-S cells was detected by immunofluorescence. IL-1β level in the lavage fluid and MH-S cells were detected by enzyme-linked immunosorbent assay. Protein expression was detected by Western blot. Autophagy assay in MH-S cells was performed by LC3B-GFP punctae experiment.PM2.5 exposure induced the lung injury of mice and increased NLRP3, P62, Wnt5a, LC3BII/I, and CD80 expression and IL-1β release in the lung tissues. PM2.5 treatment increased NLRP3, pro-caspase-1, cleaved caspase-1, Pro-IL-1β, Pro-IL-18, P62, LC3BII/I, and Wnt5a expression, IL-1β release, and LC3B-GFP punctae in MH-S cells. However, BOX5 treatment counteracted this effect of PM2.5 on lung tissues of mice and MH-S cells. Rapamycin reversed the effect of BOX5 on PM2.5-induced lung tissues of mice and MH-S cells.PM2.5 activated the NLRP3 inflammasome and IL-1β release in MH-S cells by facilitating the autophagy via activating Wnt5a. The findings of this study provided a new clue for the treatment of pulmonary inflammation caused by PM2.5.

Lipid emulsion attenuates propranolol-induced early apoptosis in rat cardiomyoblasts

OBJECTIVE

Propranolol is used to treat several cardiovascular diseases; however, toxic doses of propranolol cause severe myocardial depression and cardiac arrest. The aim of this study was to examine the effects of lipid emulsion (LE) on cardiotoxicity induced by toxic doses of propranolol in H9C2 rat cardiomyoblast cell line and to elucidate the underlying mechanism.

METHODS

The experimental groups comprised control, propranolol alone, esmolol alone, or LE followed by propranolol or esmolol treatment, and reactive oxygen species (ROS) inhibitor N-acetyl-L-cysteine (NAC) followed by propranolol treatment. The effects of propranolol, esmolol, NAC, and LE, alone or in combination, on cell viability, apoptosis, and ROS production were examined. Additionally, we investigated the effect of LE on propranolol concentration.

RESULTS

LE and NAC reversed the inhibition of cell viability induced by propranolol (p < .001). However, LE had no effect on the inhibition of cell viability caused by esmolol. The LE inhibited propranolol-induced expressions of cleaved caspase-3 (p < .001), caspase-9 (p < .001), and Bax (p < .01), but not caspase-8. NAC inhibited the propranolol-induced expression of cleaved caspase-3. LE inhibited propranolol-induced early apoptosis, but had no effect on late apoptosis. Additionally, LE inhibited the number of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive cells generated by propranolol. It attenuated propranolol-induced ROS production. However, it had no effect on propranolol concentration.

CONCLUSION

LE inhibits early apoptosis caused by a toxic dose of propranolol by suppressing the intrinsic apoptotic pathway, via direct inhibition of ROS production.

Magnetic resonance imaging investigations reveal that PM2.5 exposure triggers visual dysfunction in mice

OBJECTIVES

To investigate how PM_2.5 exposure affects the microstructure, metabolites or functions of the visual system.

METHODS

C57BL/6J mice were randomly assigned to groups exposed to the filtered air (the control group) or the concentrated ambient PM_2.5 (the PM_2.5 group). Visual evoked potentials (VEP), electroretinograms (ERG), diffusion tensor imaging (DTI), proton magnetic resonance spectroscopy (¹H-MRS) and resting-state functional MRI (rsfMRI) were performed. Parameters were obtained and compared between the two groups, including latencies and amplitudes of the P1 wave, N1 wave and P2 wave from VEP, latencies and amplitudes of the a wave and b wave from ERG, fractional anisotropy (FA), mean diffusion (MD), axial diffusivity (AD) and radial diffusivity (RD) from DTI, visual cortex (VC) metabolites from ¹H-MRS, and regional homogeneity (ReHo) from rsfMRI.

RESULTS

Compared with the values of the control group, the PM_2.5 group showed a prolonged N1 latency (43.11 ± 7.94 ms vs. 38.75 ± 4.60 ms) and lowered P1 amplitude (5.62 ± 4.38 μV vs. 8.56 ± 5.92 μV) on VEP (all p < 0.05). On ERG, the amplitude of the a wave was lowered (- 91.39 ± 56.29 μV vs. - 138.68 ± 89.05 μV), the amplitude of the b wave was lowered (194.38 ± 126.27 μV vs. 284.72 ± 170.99 μV), and the latency of the b wave was prolonged (37.78 ± 10.72 ms vs. 33.01 ± 4.34 ms) than the values of the control group (all p < 0.05). DTI indicated FA increase in the bilateral piriform cortex (Pir), FA decrease in the bilateral somatosensory cortex (S) and the bilateral striatum (Stri), AD decrease in the bilateral VC, the right S and the bilateral Pir, MD decrease in the bilateral Pir, and RD decrease in the bilateral Pir in the PM_2.5 mice (all p < 0.05, Alphasim corrected). ¹H-MRS showed Glutamate (Glu) increase and Phosphocholine (PCh) increase in the VC of the PM_2.5 group than those of the control group (PCh 1.63 ± 0.25 vs. 1.50 ± 0.25; PCh/total creatine(tCr) 0.19 ± 0.03 vs. 0.18 ± 0.03; Glu 10.46 ± 1.50 vs. 9.60 ± 1.19; Glu/tcr 1.23 ± 0.11 vs. 1.12 ± 0.11) (all p < 0.05). rsfMRI showed higher ReHo in the PM_2.5 mice in the left superior colliculus, the left motor cortex, the hippocampus, the periaqueductal gray and the right mesencephalic reticular formation (all p < 0.01, AlphaSim corrected).

CONCLUSIONS

This study revealed that PM_2.5 exposure triggered visual dysfunction, and altered microstructure, metabolite and function in the retina and visual brain areas along the visual system.

Schisandrae Fructus ethanol extract attenuates particulate matter 2.5-induced inflammatory and oxidative responses by blocking the activation of the ROS-dependent NF-κB signaling pathway

BACKGROUND/OBJECTIVES

Schisandrae Fructus, the fruit of Schisandra chinensis Baill., has traditionally been used as a medicinal herb for the treatment of various diseases, and has proven its various pharmacological effects, including anti-inflammatory and antioxidant activities. In this study, we investigated the inhibitory effect of Schisandrae Fructus ethanol extract (SF) on inflammatory and oxidative stress in particulate matter 2.5 (PM2.5)-treated RAW 264.7 macrophages.

MATERIALS/METHODS

To investigate the anti-inflammatory and antioxidant effects of SF in PM2.5-stimulated RAW 264.7 cells, the levels of pro-inflammatory mediator such as nitric oxide (NO) and prostaglandin E₂ (PGE₂), cytokines including interleukin (IL)-6 and IL-1β, and reactive oxygen species (ROS) were measured. To elucidate the mechanism underlying the effect of SF, the expression of genes involved in the generation of inflammatory factors was also investigated. We further evaluated the anti-inflammatory and antioxidant efficacy of SF against PM2.5 in the zebrafish model.

RESULTS

The results indicated that SF treatment significantly inhibited the PM2.5-induced release of NO and PGE₂, which was associated with decreased inducible NO synthase and cyclooxygenase-2 expression. SF also attenuated the PM2.5-induced expression of IL-6 and IL-1β, reducing their extracellular secretion. Moreover, SF suppressed the PM2.5-mediated translocation of nuclear factor-kappa B (NF-κB) from the cytosol into nuclei and the degradation of inhibitor IκB-α, indicating that SF exhibited anti-inflammatory effects by inhibiting the NF-κB signaling pathway. In addition, SF abolished PM2.5-induced generation of ROS, similar to the pretreatment of a ROS scavenger, but not by an inhibitor of NF-κB activity. Furthermore, SF showed strong protective effects against NO and ROS production in PM2.5-treated zebrafish larvae.

CONCLUSIONS

Our findings suggest that SF exerts anti-inflammatory and antioxidant effects against PM2.5 through ROS-dependent down-regulating the NF-κB signaling pathway, and that SF can be a potential functional substance to prevent PM2.5-mediated inflammatory and oxidative damage.

Blocking connexin43 hemichannels prevents TGF-β2 upregulation and epithelial-mesenchymal transition in retinal pigment epithelial cells

Epithelial-mesenchymal transition (EMT) occurs when polarised epithelial cells change to a mesenchymal phenotype. EMT plays a role in several chronic conditions, including ocular diseases with retinal pigment epithelium (RPE) EMT associated with retinal diseases such as diabetic retinopathy (DR). Here, EMT results in breakdown of the blood-retinal barrier (BRB) leading to sub-retinal fluid deposition and retinal detachment. Previous studies have shown that blocking connexin43 (Cx43) hemichannels can protect against RPE BRB breakdown, but the underlying mechanism is unknown. To determine whether open Cx43 hemichannels may enable EMT of RPE cells and thus result in BRB breakdown, ARPE-19 cells were either challenged with high glucose plus the inflammatory cytokines IL-1β and TNF-α (HG + Cyt) to simulate DR or treated with the Cx43 hemichannel blocker tonabersat alongside the HG + Cyt challenge. HG + Cyt induced a morphological change in RPE cells to a fibroblastic phenotype with a corresponding decrease in epithelial zonular occludens-1 and an increase in the fibroblastic marker α-SMA. The HG + Cyt challenge also induced loss of transepithelial electrical resistance while increasing dye passage between RPE cells. All of these changes were significantly reduced with tonabersat treatment, which also prevented HG + Cyt-induced transforming growth factor-β2 (TGF-β2) release. In conclusion, Cx43 hemichannel block with tonabersat attenuated both TGF-β2 release and RPE EMT under disease-mimicking conditions, offering the potential to ameliorate the progression of EMT-associated retinal diseases.

The Protective Effect of Topical Spermidine on Dry Eye Disease with Retinal Damage Induced by Diesel Particulate Matter2.5

Air pollutants, especially ambient fine particulate matter2.5, may contribute to various ocular surface disorders, including dry eye disease, keratitis and conjunctivitis. A natural polyamine spermidine has a protective effect on the retina and optic nerve; however, no study has been conducted on the application of spermidine in particulate matter2.5-induced dry eye disease. In the present study, we investigated the effect of spermidine eye drops in topically exposed particulate matter2.5-induced dry eye models of Sprague-Dawley rats, by hematological, biochemical and histological evaluation. Spermidine eye drops attenuated the particulate matter2.5 exposure-induced reduction of tear secretion and corneal epithelial damage. Furthermore, spermidine protected against conjunctival goblet cell loss and retinal ganglion cell loss induced by particulate matter2.5. Additionally, spermidine markedly prevented particulate matter2.5-induced infiltration of cluster of differentiation3⁺ and cluster of differentiation4⁺ T lymphocytes and F4/80⁺ macrophages on lacrimal gland. Moreover, over expression of pro-inflammatory cytokines, including tumor necrosis factor-α, interleukin-6 and interleukin-17 in the lacrimal gland and cornea. Meanwhile, the levels of serum total cholesterol and low-density lipoprotein cholesterol were markedly increased by topical exposure to particulate matter2.5, but this change in the lipid profile was decreased by spermidine. Taken together, spermidine may have protective effects against particulate matter2.5-induced dry eye symptoms via stabilization of the tear film and suppression of inflammation and may in part contribute to improving retinal function and lipid metabolism disorder.

2-IPMA Ameliorates PM2.5-Induced Inflammation by Promoting Primary Ciliogenesis in RPE Cells

Primary cilia mediate the interactions between cells and external stresses. Thus, dysregulation of primary cilia is implicated in various ciliopathies, e.g., degeneration of the retina caused by dysregulation of the photoreceptor primary cilium. Particulate matter (PM) can cause epithelium injury and endothelial dysfunction by increasing oxidative stress and inflammatory responses. Previously, we showed that PM disrupts the formation of primary cilia in retinal pigment epithelium (RPE) cells. In the present study, we identified 2-isopropylmalic acid (2-IPMA) as a novel inducer of primary ciliogenesis from a metabolite library screening. Both ciliated cells and primary cilium length were increased in 2-IPMA-treated RPE cells. Notably, 2-IPMA strongly promoted primary ciliogenesis and restored PM2.5-induced dysgenesis of primary cilia in RPE cells. Both excessive reactive oxygen species (ROS) generation and activation of a stress kinase, JNK, by PM2.5 were reduced by 2-IPMA. Moreover, 2-IPMA inhibited proinflammatory cytokine production, i.e., IL-6 and TNF-α, induced by PM2.5 in RPE cells. Taken together, our data suggest that 2-IPMA ameliorates PM2.5-induced inflammation by promoting primary ciliogenesis in RPE cells.

The Protective Effect of Oral Application of Corni Fructus on the Disorders of the Cornea, Conjunctiva, Lacrimal Gland and Retina by Topical Particulate Matter 2.5

Particulate matter 2.5 (PM_2.5) may aggravate dry eye disease (DED). Corni Fructus (CF), which is fruit of Cornus officinalis Sieb. et Zucc., has been reported to have various beneficial pharmacological effects, whereas the effect of CF on the eye is still unknown. Therefore, in this study, we investigated the effect of oral administration of water extract of CF (CFW) on the eye, hematology, and biochemistry in a DED model induced by topical exposure to PM_2.5. Furthermore, the efficacy of CFW compared with cyclosporine (CsA), an anti-inflammatory agent, and lutein, the posterior eye-protective agent. Sprague-Dawley rats were topically administered 5 mg/mL PM_2.5 in both eyes four times daily for 14 days. During the same period, CFW (200 mg/kg and 400 mg/kg) and lutein (4.1 mg/kg) were orally administered once a day. All eyes of rats in the 0.05% cyclosporine A (CsA)-treated group were topically exposed to 20 μL of CsA, twice daily for 14 days. Oral administration of CFW attenuated the PM_2.5-induced reduction of tear secretion and corneal epithelial damage. In addition, CFW protected against goblet cell loss in conjunctiva and overexpression of inflammatory factors in the lacrimal gland following topical exposure to PM_2.5. Furthermore, CFW markedly prevented PM_2.5-induced ganglion cell loss and recovered the thickness of inner plexiform layer. Meanwhile, CFW treatment decreased the levels of total cholesterol and low-density lipoprotein cholesterol in serum induced by PM_2.5. Importantly, the efficacy of CFW was superior or similar to that of CsA and lutein. Taken together, oral administration of CFW may have protective effects against PM_2.5-induced DED symptoms via stabilization of the tear film and suppression of inflammation. Furthermore, CFW may in part contribute to improving retinal function and lipid metabolism disorder.

Sulforaphane Alleviates Particulate Matter-Induced Oxidative Stress in Human Retinal Pigment Epithelial Cells

Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly, and oxidative damage to retinal pigment epithelial (RPE) cells plays a major role in the pathogenesis of AMD. Exposure to high levels of atmospheric particulate matter (PM) with an aerodynamic diameter of <2.5 μm (PM2.5) causes respiratory injury, primarily due to oxidative stress. Recently, a large community-based cohort study in the UK reported a positive correlation between PM2.5 exposure and AMD. Sulforaphane (SFN), a natural isothiocyanate found in cruciferous vegetables, has known antioxidant effects. However, the protective effects of SNF in the eye, especially in the context of AMD, have not been evaluated. In the present study, we evaluated the effect of SFN against PM2.5-induced toxicity in human RPE cells (ARPE-19) and elucidated the molecular mechanism of action. Exposure to PM2.5 decreased cell viability in ARPE-19 cells in a time- and dose-dependent manner, potentially due to elevated intracellular reactive oxygen species (ROS). SFN treatment increased ARPE-19 cell viability and decreased PM2.5-induced oxidative stress in a dose-dependent manner. PM2.5-induced downregulation of serum- and glucocorticoid-inducible kinase 1 (SGK1), a cell survival factor, was recovered by SFN. PM2.5 treatment decreased the enzymatic activities of the antioxidant enzymes including superoxide dismutase and catalase, which were restored by SFN treatment. Taken together, these findings suggest that SFN effectively alleviates PM2.5-induced oxidative damage in human ARPE-19 cells via its antioxidant effects, and that SFN can potentially be used as a therapeutic agent for AMD, particularly in cases related to PM2.5 exposure.

PM2.5 aggravates NQO1-induced mucus hyper-secretion through release of neutrophil extracellular traps in an asthma model

BACKGROUND

Particulate matter of 2.5 µm or less in diameter (PM2.5) is one of the most complex pollutants in the atmospheric environment and harmful to human health. Epidemiologic evidence suggests that asthma exacerbation is associated with PM2.5 exposure. However, the molecular mechanism of PM2.5 in the development of asthma is not fully addressed.

METHODS

PM2.5 was collected from Chengdu, China, and the components were analyzed. The relationship between PM2.5 exposure and asthma severity was investigated in an Ovalbumin (OVA)-induced murine model of asthma. U-BIOPRED data from public database and our own RNA-seq data were analyzed to identify the hub genes. Real-time qPCR, immunofluorescence, immunohistochemistry and pathological staining were applied for mechanism dissection in both in vitro and in vivo studies.

RESULTS

In PM2.5 samples, a total of 11 elements including major elements and trace elements were identified, 14 of the 16 Polycyclic aromatic hydrocarbons (PAHs) were detected except Acenaphthene and Fluorene. PM2.5 exposure aggravated pulmonary inflammation, mucus secretion, and neutrophils infiltration in asthma model. Based on transcriptome analysis of mild-to-severe asthma dataset, it showed that mucus secretion and neutrophil degranulation correlated with asthma severity. Moreover, NAD(P)H:quinone oxidoreductase 1 (NQO1) was screened out as a hub gene whose expression positively correlated with MUC5AC expression in patient with asthma by performing joint analysis. Furthermore, in OVA-induced asthma model and in vitro assay, it also revealed that PM2.5-induced MU5AC expression was regulated by NQO1 through neutrophil extracellular traps (NETs) caused by oxidative stress.

CONCLUSION

Taken together, we discovered a potential relationship between asthma severity and PM2.5 exposure. In addition, neutrophil depletion, NETs inhibition or anti-NQO1 might be novel potential therapeutic options for treatment of PM2.5-induced mucus hyper-secretion.

PM2.5-induced pulmonary inflammation via activating of the NLRP3/caspase-1 signaling pathway

Particulate matter 2.5 (PM2.5)-induced pulmonary inflammation has become a public concern in recent years. In which, the activation of the NLRP3/caspase-1 pathway was closely related to the inflammatory response of various diseases. However, the promotion effect of the NLRP3/caspase-1 pathway on PM2.5-induced pulmonary inflammation remains largely unclear. Here, our data showed that PM2.5 exposure caused lung injury in the mice by which inflammatory cell infiltration occurred in lung and alveolar structure disorder. Meanwhile, the exposure of human bronchial epithelial cells (16HBE) to PM2.5 resulted in suppressed cell viability, as well as elevated cell apoptosis. Moreover, a higher level of inflammatory cytokine and activation of the NLRP3/caspase-1 pathway in PM2.5-induced inflammation mice models and 16HBE cells. Mechanistically, pretreatment with MCC950, a NLRP3/caspase-1 pathway inhibitor, prevented PM2.5-induced lung injury, inflammatory response, and the number of inflammatory cells in BALFs, as well as promoted cell viability and decreased inflammatory cytokine secretion. Collectively, our findings indicated that the NLRP3/caspase-1 pathway serves a vital role in the pathological changes of pulmonary inflammation caused by PM2.5 exposure. MCC950 was expected to be the therapeutic target of PM2.5 inhalation mediated inflammatory diseases.

The Impact of Particulate Matter (PM2.5) on Human Retinal Development in hESC-Derived Retinal Organoids

Increasing evidence demonstrated that PM2.5 could cross the placenta and fetal blood-brain barrier, causing neurotoxicity of embryonic development. The retina, an embryologic extension of the central nervous system, is extremely sensitive and vulnerable to environmental insults. The adverse effects of PM2.5 exposure on the retina during embryonic neurodevelopment are still largely unknown. Our goal was to investigate the effect of PM2.5 on human retinal development, which was recapitulated by human embryonic stem cell (hESC)-derived retinal organoids (hEROs). In the present study, using the hEROs as the model, the influences and the mechanisms of PM2.5 on the developing retina were analyzed. It demonstrated that the formation rate of the hERO-derived neural retina (NR) was affected by PM2.5 in a concentration dosage-dependent manner. The areas of hEROs and the thickness of hERO-NRs were significantly reduced after PM2.5 exposure at the concentration of 25, 50, and 100 μg/ml, which was due to the decrease of proliferation and the increase of apoptosis. Although we did not spot significant effects on retinal differentiation, PM2.5 exposure did lead to hERO-NR cell disarranging and structural disorder, especially retinal ganglion cell dislocation. Transcriptome analysis showed that PM2.5 treatment was significantly associated with the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/AKT pathways and reduced the level of the fibroblast growth factors (FGFs), particularly FGF8 and FGF10. These results provided evidence that PM2.5 exposure potentially inhibited proliferation and increased apoptosis at the early development stage of the human NR, probably through the MAPK and PI3K/Akt pathway. Our study suggested that exposure to PM2.5 suppressed cell proliferation and promoted cell apoptosis, thereby contributing to abnormal human retinal development.

Fine particulate matter PM2.5 generated by building demolition increases the malignancy of breast cancer MDA-MB-231 cells

OBJECTIVES

This study investigates the effects of water-extracted PM_2.5 on a triple-negative breast cancer (TNBC) cell line, MDA-MB-231, by sampling suspended particulates around a building demolition site.

METHODS

PM_2.5 particles were obtained using a high-flow TISCH sampler. Water-soluble PM_2.5 were extracted by an ultrasonic oscillator and then freeze-dried. The heavy metal components of soluble PM_2.5 was analyzed by ICP-MS. Cell viability was evaluated by MTT assay for cells that were exposed to PM_2.5 (200, 400 and 600 μg/mL). Wound healing and transwell cell migration and invasion assays were used to measure cell motility and the invasiveness of cancer cells that had been exposed to PM_2.5 into a chemo-attractant substance. Interrelated mechanisms of cancer malignancy were analyzed by Western blot analysis.

RESULTS

Nearby PM_2.5 concentrations increased significantly during the deconstruction of buildings, and the Cd, Cu, Pb, Zn and Cr contents of soluble PM_2.5 also significantly increased. Following exposure to PM_2.5, the survival rate of breast cancer cells was significantly higher than that of the control group. Soluble PM_2.5-treated cells had a higher migration capacity. The signaling pathway of FAK/PI3K/AKT proteins was more activated in PM_2.5-treated cells than the control group. Increased levels of Aurora B and Bcl-2 were associated with cell proliferation. Elevated levels of cathepsins D, β-catenin, N-cadherin, vimentin and MMP-9 were associated with breast cancer cell metastasis.

CONCLUSION

Soluble PM_2.5 from building demolition may promote/progress in surviving TNBC cells, increasing the malignancy of breast cancer. This study offered evidence of a link between demolition PM_2.5 and cancer progression.

Urban Aerosol Particulate Matter Promotes Necrosis and Autophagy via Reactive Oxygen Species-Mediated Cellular Disorders that are Accompanied by Cell Cycle Arrest in Retinal Pigment Epithelial Cells

Urban particulate matter (UPM) is recognized as a grave public health problem worldwide. Although a few studies have linked UPM to ocular surface diseases, few studies have reported on retinal dysfunction. Thus, the aim of the present study was to evaluate the influence of UPM on the retina and identify the main mechanism of UPM toxicity. In this study, we found that UPM significantly induced cytotoxicity with morphological changes in ARPE-19 human retinal pigment epithelial (RPE) cells and increased necrosis and autophagy but not apoptosis. Furthermore, UPM significantly increased G2/M arrest and simultaneously induced alterations in cell cycle regulators. In addition, DNA damage and mitochondrial dysfunction were remarkably enhanced by UPM. However, the pretreatment with the potent reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine (NAC) effectively suppressed UPM-mediated cytotoxicity, necrosis, autophagy, and cell cycle arrest. Moreover, NAC markedly restored UPM-induced DNA damage and mitochondrial dysfunction. Meanwhile, UPM increased the expression of mitophagy-regulated proteins, but NAC had no effect on mitophagy. Taken together, although further studies are needed to identify the role of mitophagy in UPM-induced RPE injury, the present study provides the first evidence that ROS-mediated cellular damage through necrosis and autophagy is one of the mechanisms of UPM-induced retinal disorders.

Diesel Particulate Matter 2.5 Induces Epithelial-to-Mesenchymal Transition and Upregulation of SARS-CoV-2 Receptor during Human Pluripotent Stem Cell-Derived Alveolar Organoid Development

Growing evidence links prenatal exposure to particulate matter (PM2.5) with reduced lung function and incidence of pulmonary diseases in infancy and childhood. However, the underlying biological mechanisms of how prenatal PM2.5 exposure affects the lungs are incompletely understood, which explains the lack of an ideal in vitro lung development model. Human pluripotent stem cells (hPSCs) have been successfully employed for in vitro developmental toxicity evaluations due to their unique ability to differentiate into any type of cell in the body. In this study, we investigated the developmental toxicity of diesel fine PM (dPM2.5) exposure during hPSC-derived alveolar epithelial cell (AEC) differentiation and three-dimensional (3D) multicellular alveolar organoid (AO) development. We found that dPM2.5 (50 and 100 μg/mL) treatment disturbed the AEC differentiation, accompanied by upregulation of nicotinamide adenine dinucleotide phosphate oxidases and inflammation. Exposure to dPM2.5 also promoted epithelial-to-mesenchymal transition during AEC and AO development via activation of extracellular signal-regulated kinase signaling, while dPM2.5 had no effect on surfactant protein C expression in hPSC-derived AECs. Notably, we provided evidence, for the first time, that angiotensin-converting enzyme 2, a receptor to mediate the severe acute respiratory syndrome coronavirus clade 2 (SARS-CoV-2) entry into target cells, and the cofactor transmembrane protease serine 2 were significantly upregulated in both hPSC-AECs and AOs treated with dPM2.5. In conclusion, we demonstrated the potential alveolar development toxicity and the increase of SARS-Cov-2 susceptibility of PM2.5. Our findings suggest that an hPSC-based 2D and 3D alveolar induction system could be a useful in vitro platform for evaluating the adverse effects of environmental toxins and for virus research.

Polarity and epithelial-mesenchymal transition of retinal pigment epithelial cells in proliferative vitreoretinopathy

Under physiological conditions, retinal pigment epithelium (RPE) is a cellular monolayer composed of mitotically quiescent cells. Tight junctions and adherens junctions maintain the polarity of RPE cells, and are required for cellular functions. In proliferative vitreoretinopathy (PVR), upon retinal tear, RPE cells lose cell-cell contact, undergo epithelial-mesenchymal transition (EMT), and ultimately transform into myofibroblasts, leading to the formation of fibrocellular membranes on both surfaces of the detached retina and on the posterior hyaloids, which causes tractional retinal detachment. In PVR, RPE cells are crucial contributors, and multiple signaling pathways, including the SMAD-dependent pathway, Rho pathway, MAPK pathways, Jagged/Notch pathway, and the Wnt/β-catenin pathway are activated. These pathways mediate the EMT of RPE cells, which play a key role in the pathogenesis of PVR. This review summarizes the current body of knowledge on the polarized phenotype of RPE, the role of cell-cell contact, and the molecular mechanisms underlying the RPE EMT in PVR, emphasizing key insights into potential approaches to prevent PVR.

Down-regulation of diesel particulate matter-induced airway inflammation by the PDZ motif peptide of ZO-1

Although diesel airborne particulate matter (PM2.5) has been known to play a role in many human diseases, there is no direct evidence that therapeutic drugs or proteins can diminish PM2.5-induced diseases. Nevertheless, studies examining the negative control mechanisms of PM2.5-induced diseases are critical to develop novel therapeutic medications. In this study, the consensus PDZ peptide of ZO-1 inhibited PM2.5-induced inflammatory cell infiltration, pro-inflammatory cytokine gene expression, and TEER in bronchoalveolar lavage (BAL) fluid and AM cells. Our data indicated that the PDZ domain in ZO-1 is critical for regulation of the PM2.5-induced inflammatory microenvironment. Therefore, the PDZ peptide may be a potential therapeutic candidate during PM-induced respiratory diseases.