PM2.5 exposure increases dry eye disease risks through corneal epithelial inflammation and mitochondrial dysfunctions

Stibene glucoside prevents PM2.5 caused pulmonary fibrosis by Pseudo hypoxia, autophagy and NF-κB signal pathways

Although the association between PM2.5 exposure and pulmonary fibrosis is well-documented, the underlying molecular mechanisms remain poorly understood, and effective preventive strategies against PM2.5-induced pulmonary toxicity are yet to be established‌. This study investigated the role of reactive oxygen species (ROS)-mediated pseudo-hypoxia signaling and NF-κB pathway activation in PM2.5-triggered epithelial-mesenchymal transition (EMT) and fibrosis, alongside the therapeutic potential of the antioxidant compound stilbene glucoside (TSG). ‌In vivo‌, C57BL/6 mice exposed to PM2.5 for two months developed pulmonary fibrosis, with transcriptomic analysis revealing significant alterations in pathways associated with carbohydrate metabolism, cancer signaling, and immune-related diseases‌. Concurrently, upregulated expression of EMT markers (fibronectin, vimentin), glycolysis-related genes (PKM, LDHA), and inflammatory cytokines (TGF-beta) was observed in lung tissues‌. ‌In vitro‌, PM2.5 induced EMT in BEAS-2B cells via ROS-driven mitochondrial membrane potential collapse, mitophagy, HIF-1α activation, and NF-κB-mediated inflammation, which collectively promoted a metabolic shift toward glycolysis‌. Notably, TSG treatment attenuated PM2.5-induced pulmonary fibrosis by suppressing ROS accumulation, pseudo-hypoxia signaling, and NF-κB pathway activation. These effects correlated with restored mitochondrial function and normalized glucose metabolism in cellular models‌. ‌We come to the conclusion that PM2.5 exacerbates pulmonary fibrosis through ROS/HIF-1α and NF-κB axis-driven EMT and metabolic reprogramming. TSG, as a multifunctional antioxidant, represents a promising prophylactic agent against PM2.5-associated pulmonary damage‌.

κ-Carrageenan from Grateloupia filicina protects against PM2.5-induced intraocular pressure elevation

This study investigates the efficacy of GFP01, an almost pure κ-carrageenan derived from Grateloupia filicina, in counteracting intraocular pressure (IOP) elevation induced by PM2.5 exposure. GFP01, characterized by a molecular weight of 97.8 kDa, exhibits a linear backbone composed of 4-O-sulfated-β-D-galactose and 3,6-anhydro-α-D-galactose. In a murine model subjected to PM2.5-induced high IOP, GFP01 treatment significantly mitigated IOP compared to the PM2.5 group (n = 12, p < 0.01). In vitro assays revealed a 27.7 % increase in cell viability in human trabecular meshwork cells (HTMCs) treated with GFP01 compared to controls exposed to PM2.5 (p < 0.001, n = 5 cell lines). Additionally, GFP01 decreased PM2.5-induced transendothelial electrical resistance (TEER) of angular aqueous plexus (AAP) cells by 35.8 % at 48 h post-treatment (p < 0.05, n = 3 cell lines). Western blot analysis further demonstrated GFP01's role in inhibiting NLRP3/caspase-1/GSDMD/IL-1β axis in ocular tissues and HTMCs. Cytotoxicity assessment and slit-lamp imaging confirmed the safety of GFP01. In conclusion, GFP01 demonstrates a significant protective effect against PM2.5-induced IOP elevation, making it a promising therapeutic candidate for clinical applications.

Rebamipide Enhances Pathogen Defense and Mitigates Inflammation in a Particulate Matter-Induced Ocular Surface Inflammation Rat Model

Particulate matter (PM) exposure is known to induce significant ocular surface inflammation, necessitating effective therapeutic interventions. This study compared the efficacy of 2% rebamipide (REB) with 0.1% hyaluronic acid (HA) eye drops in investigating the anti-inflammatory and pathogen-clearance effects in a PM-induced ocular surface inflammation model using Sprague-Dawley (SD) rats. Parameters including clinical signs, histological changes, mucin secretions, inflammatory cytokines, mast cell degranulation, dysregulated cell proliferation, and cellular apoptosis were evaluated. 2% REB alleviated ocular surface inflammation by downregulating the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) inflammatory pathway and upregulating epidermal growth factor receptor (EGFR) signaling, thereby enhancing mucin secretion and promoting pathogen clearance. Histopathological analysis, western blot, and immunohistochemical staining revealed a marked reduction in inflammatory markers including MMP-9, IL-1β, TNF-α, IL-17, and CD-4, decreased mast cell degranulation, increased goblet cell density, and enhanced expression of mucins, including MUC5AC and MUC16, in the 2% REB-treated group compared to the 0.1% HA-treated and PM-exposed groups. Moreover, 2% REB demonstrated decreased apoptosis (TUNEL) and reduced uncontrolled cell proliferation (Ki67), indicating improved cellular integrity. In conclusion, 2% REB is a promising treatment option for PM-induced ocular surface inflammation in a rat model compared with 0.1% HA, offering the benefits of reducing inflammation, clearing pathogens, and protecting overall ocular health.

Tagetes erecta Linn flower extract inhibits particulate matter 2.5-promoted epithelial-mesenchymal transition by attenuating reactive oxygen species generation in human retinal pigment epithelial ARPE-19 cells

BACKGROUND/OBJECTIVES

Particulate matter 2.5 (PM2.5) exposure can promote epithelial-mesenchymal transition (EMT) in human retinal pigment epithelial (RPE) cells. The flowers of Tagetes erecta Linn, commonly known as marigold, are rich in diverse flavonoids and carotenoids and play a significant role in preventing cellular damage induced by oxidative stress, but the role of their extracts in RPE cells has not been reported. This study aimed to evaluate the influence of an ethanol extract of T. erecta Linn flower (TE) on PM2.5-induced EMT processes in RPE ARPE-19 cells.

MATERIALS/METHODS

To investigate the protective effect of TE against ARPE-19 cell damage following PM2.5 treatment, cells were exposed to TE for 1 h before exposure to PM2.5 for 24 h. We investigated whether the efficacy of TE on suppressing PM2.5-induced EMT was related to antioxidant activity and the effect on the expression changes of factors involved in EMT regulation. Additionally, we further explored the role of intracellular signaling pathways associated with EMT inhibition.

RESULTS

TE significantly blocked PM2.5-induced cytotoxicity while effectively preventing mitochondrial dysfunction, increased reactive oxygen species (ROS) generation, and mitochondrial membrane potential disruption. TE inhibited PM2.5-induced EMT and inflammatory response by suppressing the ROS-mediated transforming growth factor-β/suppressor of mothers against decapentaplegic/mitogen-activated protein kinases signaling pathway.

CONCLUSION

Our results suggest that marigold extract is a highly effective in protection against PM2.5-induced eye damage.

Association between indoor ventilation frequency and low muscle mass among older adults in China: a national cross-sectional research

Previous studies have established associations between indoor air pollution and loss of muscle mass. While indoor ventilation improves indoor air quality, its association with low muscle mass (LMM) remains unexplored. We investigated the association between indoor ventilation frequency (IVF) and LMM in older Chinese adults. Utilizing data from the China Longitudinal Healthy Longevity Survey (CLHLS), IVF was assessed via self-reported weekly window-opening frequency in each season of the past year. LMM was defined using appendicular skeletal muscle mass (ASM) prediction equations. Binary logistic regression models were employed to evaluate the association between IVF and LMM, with subgroup and sensitivity analyses conducted. After adjusting for covariates, participants with intermediate IVF (OR: 0.805; 95% CI: 0.669-0.969) and high IVF (OR: 0.818; 95% CI: 0.684-0.979) were 19.5% and 18.2% less likely to develop LMM, compared with participants with low IVF. The probability of LMM in the spring was 25.3% (OR: 0.747; 95% CI: 0.581-0.961) and 23.3% (OR: 0.767; 95% CI: 0.597-0.985) lower in the middle and high IVF elderly populations, respectively, whereas the probability of LMM in the spring was 36.5% (OR: 0.625; 95% CI: 0.474-0.824) and 34.1% (OR: 0.659; 95% CI: 0.501-0.868). The association between IVF and LMM was statistically significant (p < 0.05) in gender, age, residence, living arrangement, marital status, economic situation, work, smoking, drinking, exercise, cooking ventilation, life satisfaction, self-rated health, hypertension, diabetes, heart disease, dementia, and NO2. Interaction analyses showed a significant interaction effect between the drinking subgroup and IVF (P for interaction < 0.05). Higher IVF is significantly associated with a lower risk of LMM. Optimizing ventilation practices may mitigate LMM burden in older adults, informing personalized health strategies.

The alterations of ocular surface metabolism and the related immunity inflammation in dry eye

Background

Dry eye disease (DED) stands as a prominent ocular condition of global prevalence, emerging as a growing concern within public health. However, the underlying mechanisms involved in its pathogenesis remain largely unknown. In recent years, with the development of metabolomics, numerous studies have reported alterations in ocular surface metabolism in DED and offered fresh perspectives on the development of DED.

Main text

The metabolic changes of the ocular surface of DED patients are closely intertwined with the cellular metabolism process and immune inflammation changes. This article expounds upon the correlation between ocular surface metabolism and immune inflammation alterations in DED in terms of glycolysis, lipid metabolism, amino acid metabolism, cellular signaling pathways, and immune inflammation regulation.

Conclusions

The alterations in ocular surface metabolism of patients with dry eye are closely associated with their inflammatory status. Our work contributes novel insights into the pathogenesis of dry eye diseases and offers innovative molecular targets for diagnosing, detecting, and managing DED patients.

Impact of particulate matter and air pollution on ocular surface disease: A systematic review of preclinical and clinical evidence

PURPOSE

Exposure to particulate matter (PM) and air pollution has been implicated in the etiology of ocular surface diseases (OSD). The purpose of this systematic review is to evaluate and synthesize peer-reviewed literature on the impact of PM exposure on the ocular surface, integrating results from preclinical in vitro and in vivo studies with clinical findings to provide a comprehensive understanding of molecular mechanisms, physiological effects, clinical implications, and potential therapies to target acute and chronic PM-induced ocular toxicity.

METHODS

A systematic literature search was performed using PubMed and EMBASE over the period from 2009 to 2024 following the recommendations for the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) reporting guidelines. 102 studies were identified that met the inclusion/exclusion criteria. All studies were assessed for the risk of bias and qualitative data were analyzed.

RESULTS

Preclinical studies using models of corneal and conjunctival cells found that exposure to PM and similar air pollutants resulted in apoptosis, primarily via inflammatory and oxidative stress pathways as well as allergic and immune responses. Animal models resulted in phenotypes reminiscent of that of dry eye disease, presenting with reduced tear volumes and ocular surface damage. These results were corroborated by clinical studies, which reported that patients commonly presented with symptoms of itching, burning, and irritation, and ocular surface signs correlated with a diagnosis of dry eye disease, conjunctivitis, and allergic eye disease.

CONCLUSIONS

This systematic review provides a comprehensive summary of our current understanding of PM exposure on the ocular surface, highlighting the correlation between exposure to PM and ocular surface dysfunction.

Exposure to particulate matter (PM2.5) weakens corneal defense by downregulating thrombospondin-1 and tight junction proteins

BACKGROUND

Fine particulate matter (PM2.5) induces ocular surface toxicity through pyroptosis, oxidative stress, autophagy, and inflammatory responses. However, the precise molecular pathways through which PM2.5 causes corneal damage remain unclear. This study aims to investigate the underlying mechanisms by exposing human corneal epithelial cells (HCECs) to PM2.5.

METHODS

After the morphology and chemical composition analysis of the PM samples, we conducted both in vivo and in vitro experiments to investigate PM2.5-induced corneal epithelial damage. We assessed corneal barrier function in HCECs using transepithelial electrical resistance (TEER) assays. To explore the molecular mechanisms of PM2.5-induced corneal epithelial damage, we performed whole-transcriptome resequencing, quantitative RT-PCR, and western blotting in vitro. In addition, we analyzed mouse corneas exposed to concentrated ambient PM2.5 through immunofluorescence staining to observe the resulting changes in corneal epithelial protein expression in vivo.

RESULTS

Our results showed significant impairment of corneal epithelial barrier function in PM2.5-treated HCECs, as indicated by decreased TEER values. The expression of thrombospondin-1 (THBS1) and claudin-1, both key factors for maintaining corneal epithelial barrier integrity, was markedly reduced at the gene and protein levels in both in vitro and in vivo PM2.5 exposure models. Moreover, the levels of tight junction-associated proteins, including occludin, zonula occludens-1 (ZO-1) and ZO-2, essential components of the corneal epithelial barrier, were significantly diminished in PM2.5-treated HCECs.

CONCLUSION

PM2.5 exposure leads to corneal epithelium damage by disrupting tight junction proteins and THBS1 expression. These findings provide insight into potential pathways for PM2.5-induced ocular toxicity and underscore the need for protective strategies against such environmental pollutants.

Pathological Mechanisms of Particulate Matter-Mediated Ocular Disorders: A Review

Air pollution presents a severe risk to public health, with particulate matter (PM) identified as a significant hazardous element. However, despite the eye organ being constantly exposed to air pollution, only recently has the impact of PM on ocular health caught the attention of researchers and healthcare professionals. By compiling pertinent data, this paper aims to enhance our understanding of the underlying pathological mechanisms of PM-mediated ocular disorders and facilitate the development of effective treatment strategies. Recent data support the association between exposure to PM and the development of ocular pathologies such as dry eye syndrome, retinal atherosclerosis, and glaucoma. Based on the results of multiple studies, PM exposure can lead to oxidative stress, inflammation, autophagy, cell death, and, ultimately, the development of ophthalmic diseases. This review aims to consolidate the latest findings on PM-mediated ocular diseases by summarizing the outcomes from epidemiological, in vitro, and in vivo studies on ocular surface and retinal disorders as well as other relevant ophthalmic disorders.

cRGD-Conjugated Bilirubin Nanoparticles Alleviate Dry Eye Disease Via Activating the PINK1-Mediated Mitophagy

Purpose

The purpose of this study was to evaluate the cytoprotective effect and the mechanism of cRGD-conjugated bilirubin nanoparticles (cNPs@BR) in dry eye disease (DED).

Methods

The binding capacity and cellular uptake of cNPs@BR in human corneal epithelial cells (HCECs) were assessed by immunofluorescence. The anti-inflammation and anti-oxidative stress effects of cNPs@BR were determined by flow cytometry, immunofluorescence, Western blot, chromatin immunoprecipitation (ChIP), and ELISA assay in LPS-stimulated RAW264.7 cells and hypertonic HCECs. The function of ocular surface barrier, tear production, and the number of goblet cells after cNPs@BR treatment were further assessed by fluorescein sodium staining, phenol red cotton threads, quantitative PCR (qPCR), hematoxylin and eosin (H&E) staining, and Periodic Acid-Schiff (PAS) staining in a 0.2% BAC-induced DED mouse model. Furthermore, the mechanism of cNPs@BR in treating DED was explored by RNA sequencing and RNA interference.

Results

The cRGD peptide prolonged the retention time of nanoparticles on HCECs and enhanced the cellular uptake efficiency. In both cell models, 20 µM cNPs@BR pretreatment ameliorated oxidative stress by decreasing the intracellular reactive oxygen species (ROS) levels and the expression of NOX4 and 4-HNE, while promoting HO-1 and nuclear Nrf2 levels. Moreover, cNPs@BR alleviated the inflammatory response by inhibiting NF-κB p65 nuclear translocation and decreasing the expression of iNOS and the secretion of IL-1β, IL-6, and TNF-α. In addition, cNPs@BR protected ocular surface epithelium against oxidative stress and inflammation and restored conjunctival goblet cells in the mouse model of DED by activating PINK1-mediated mitophagy.

Conclusions

The cNPs@BR suppressed oxidative stress and inflammatory response in the ocular surface epithelium and restored goblet cells by activating PINK1-mediated mitophagy.

Impact of fine particulate matter (PM2.5) on ocular health among people living in Chiang Mai, Thailand

Considering the limited information on the impact of PM2.5 content on ocular health, a follow-up study was conducted on 50 healthy adults. Samples were collected twice, once before the PM2.5 exposure season and again after exposure. Daily PM2.5 concentration data was gathered from Thung Satok monitoring station. All subjects completed the self-structured ocular symptom questionnaire. The concentrations of 1-OHP were determined using HPLC-FLD. Logistic regression analysis investigated the relationship between PM2.5 toxicity and ocular symptoms. The findings revealed that daily PM2.5 concentrations surpassed the WHO-recommended range by around threefold. Exposure to PM2.5 significantly raised the likelihood of ocular redness (adjusted OR: 12.39, 95% CI), watering (adjusted OR: 2.56, 95% CI), and dryness (adjusted OR: 5.06, 95% CI). Additionally, these symptoms had an exposure-response relationship with increasing 1-OHP levels. Ocular symptoms worsened in frequency and severity during the high PM2.5 season, showing a strong link to elevated PM2.5 levels. Lymphocyte counts were also positively correlated with redness, watering, and dryness during high PM2.5 exposure. In conclusion, our study shows that subjects exposed to higher PM2.5 levels presented more significant ocular surface alterations.

Attenuating mitochondrial dysfunction-derived reactive oxygen species and reducing inflammation: the potential of Daphnetin in the viral pneumonia crisis

Amidst the global burden of viral pneumonia, mitigating the excessive inflammatory response induced by viral pneumonia has emerged as a significant challenge. Pneumovirus infections can lead to the persistent activation of M1 macrophages, culminating in cytokine storms that exacerbate pulmonary inflammation and contribute to the development of pulmonary fibrosis. Mitochondria, beyond their role as cellular powerhouses, are pivotal in integrating inflammatory signals and regulating macrophage polarization. Mitochondrial damage in alveolar macrophages is postulated to trigger excessive release of reactive oxygen species (ROS), thereby amplifying macrophage-mediated inflammatory pathways. Recent investigations have highlighted the anti-inflammatory potential of Daphnetin, particularly in the context of cardiovascular and renal disorders. This review elucidates the mechanisms by which viral infection-induced mitochondrial damage promotes ROS generation, leading to the phenotypic shift of alveolar macrophages towards a pro-inflammatory state. Furthermore, we propose a mechanism whereby Daphnetin attenuates inflammatory signaling by inhibiting excessive release of mitochondrial ROS, thus offering mitochondrial protection. Daphnetin may represent a promising pharmacological intervention for viral pneumonia and could play a crucial role in addressing future pandemics.

Cell death pathways in dry eye disease: Insights into ocular surface inflammation

Dry eye disease (DED) is increasingly prevalent, with inflammation playing a crucial role in its pathogenesis. Severe cases of DED result in significant ocular discomfort and visual impairment due to damage and loss of ocular surface epithelial cells. The precise mechanisms underlying the loss of these epithelial cells remain a subject of ongoing research and debate. Programmed cell death (PCD) mechanisms, including pyroptosis, apoptosis, and necroptosis, are known to be critical in maintaining ocular surface homeostasis and responding to stressors in DED. The concept of PANoptosis, which integrates elements of various PCD pathways, has been implicated in the development of numerous systemic diseases, including infections, cancer, neurodegenerative, and inflammatory conditions. It also provides novel insights into the inflammatory processes underlying DED. This review highlights the crosstalk of PCD pathways in DED, particularly the significance of PANoptosis in ocular inflammation and its potential as a therapeutic target for more effective interventions.

Effects of Air Pollution and Meteorological Conditions on DED: Associated Manifestations and Underlying Mechanisms

This study aims to explore the associations and the underlying mechanism among dry eye disease (DED), air pollution, and meteorological conditions. DED is positively correlated with air pollutants (i.e., PM2.5, PM10, O3, NO2, CO, and SO2) and meteorological conditions (i.e., high altitude and wind speed), while negatively associated with relative humidity. Both low and high air temperatures effect DED. Atmospheric pollutants affect DED mainly through necroptosis or autophagy, inflammatory responses, and oxidative stress. Meteorological factors affect DED not only by their own affects but also by dispersing the concentration of air pollutants, and then reducing the negative exposure. In summary, this review may expand the understanding of the effects of air pollution and meteorological factors on DED and emphasize the importance of air environmental protection.

Biochanin A: Disrupting the inflammatory vicious cycle for dry eye disease

Dry eye disease (DED) is a complex disorder driven by several factors like reduced tear production, increased evaporation, or poor tear quality. Oxidative stress plays a key role by exacerbating the inflammatory cycle. Previous studies explored antioxidants for DED treatment due to the link between oxidative damage and inflammation. Biochanin A (BCA) is a bioisoflavone from red clover with potent anti-inflammatory effects. This study investigated BCA's therapeutic potential for DED. Human corneal epithelial cells were cultured under hyperosmotic conditions to mimic DED. BCA treatment increased cell viability and decreased apoptosis and inflammatory cytokine expression. A DED mouse model was developed using female C57BL/6 mice in a controlled low-humidity environment combined with scopolamine injections. Mice received eye drops containing phosphate-buffered saline, low-dose BCA, or high-dose BCA. The effectiveness was evaluated by measuring tear volume, fluorescein staining, eye-closing ratio, corneal sensitivity and PAS staining. The levels of inflammatory components in corneas and conjunctiva were measured to assess DED severity. Maturation of antigen-presenting cells in cervical lymph nodes was analyzed by flow cytometry. BCA eye drops effectively reduced inflammation associated with DED in mice. BCA also decreased oxidative stress levels by reducing reactive oxygen species and enhancing the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2). These findings demonstrate that BCA ameliorates oxidative stress and ocular surface inflammation, indicating potential as a DED treatment by relieving oxidative damage and mitigating inflammation.

Inflammatory Cytokines and Chemokines Are Synergistically Induced in a ROS-Dependent Manner by a Co-Culture of Corneal Epithelial Cells and Neutrophil-like Cells in the Presence of Particulate Matter

Ocular exposure to particulate matter (PM) causes local inflammation; however, the influence of neutrophils on PM-induced ocular inflammation is still not fully understood. In this study, we constructed a system to investigate the role of PM in ocular inflammation using a co-culture of human corneal epithelial cells (HCE-T) and differentiation-induced neutrophils (dHL-60). To investigate whether HCE-T directly endocytosed PM, we performed a holographic analysis, which showed the endocytosis of PM in HCE-T. The cytokines and chemokines produced by HCE-T were measured using an ELISA. HCE-T treated with PM produced IL-6 and IL-8, which were inhibited by N-Acetyl-L-cysteine (NAC), suggesting the involvement of ROS. Their co-culture with dHL-60 enhanced their production of IL-6, IL-8, and MCP-1. This suggests an inflammatory loop involving intraocular corneal epithelial cells and neutrophils. These cytokines and chemokines are mainly regulated by NF-κB. Therefore, this co-culture system was examined in the presence of an IKK inhibitor known to downregulate NF-κB activity. The IKK inhibitor dramatically suppressed the production of these factors in co-culture supernatants. The results suggest that the inflammatory loop observed in the co-culture is mediated through ROS and the transcription factor NF-κB. Thus, the co-culture system is considered a valuable tool for analyzing complex inflammations.

Ambient air pollution exposure and the risk of probable sarcopenia: A prospective cohort study

BACKGROUND

Sarcopenia is characterized by decreased muscle mass and strength, posing threat to quality of life. Air pollutants are increasingly recognized as risk factors for diseases, while the relationship between the two remains to be elucidated. This study investigated whether exposure to ambient air pollution contributes to the development of sarcopenia.

METHODS

We employed the data from the UK Biobank with 303,031 eligible participants. Concentrations of PM2·5, NO2, and NOx were estimated. Cox proportional hazard regression models were applied to investigate the associations between pollutants and sarcopenia.

RESULTS

30,766 probable sarcopenia cases was identified during the follow-up. We observed that exposure to PM2.5 (HR, 1.232; 95% CI, 1.053-1.440), NO2 (HR, 1.055; 95% CI, 1.032-1.078) and NOx (HR, 1.016; 95% CI, 1.007-1.026) were all significantly associated with increased risk for probable sarcopenia for each 10 μg/m3 increase in pollutant concentration. In comparison with individuals in the lowest quartiles of exposure, those in the upper quartiles had significantly increased risk of probable sarcopenia. Sarcopenia-related factors, e.g., reduced lean muscle mass, diminished walking pace, and elevated muscle fat infiltration ratio, also exhibited positive associations with exposure to ambient air pollution. On the contrary, high level physical activity significantly mitigated the influence of air pollutants on the development of probable sarcopenia.

CONCLUSIONS

Air pollution exposure elevated the risk of developing sarcopenia and related manifestations in a dose-dependent manner, while physical activity maintained protective under this circumstance. Efforts should be made to control air pollution and emphasize the importance of physical activity for skeletal muscle health under this circumstance.

Mechanisms of PM10 Disruption of the Nrf2 Pathway in Cornea

We have previously shown that PM10 exposure causes oxidative stress and reduces Nrf2 protein levels, and SKQ1 pre-treatment protects against this damage in human corneal epithelial cells (HCE-2). The current study focuses on uncovering the mechanisms underlying acute PM10 toxicity and SKQ1-mediated protection. HCE-2 were pre-treated with SKQ1 and then exposed to 100 μg/mL PM10. Cell viability, oxidative stress markers, programmed cell death, DNA damage, senescence markers, and pro-inflammatory cytokines were analyzed. Nrf2 cellular location and its transcriptional activity were determined. Effects of the Nrf2 inhibitor ML385 were similarly evaluated. Data showed that PM10 decreased cell viability, Nrf2 transcriptional activity, and mRNA levels of antioxidant enzymes, but increased p-PI3K, p-NFκB, COX-2, and iNOS proteins levels. Additionally, PM10 exposure significantly increased DNA damage, phosphor-p53, p16 and p21 protein levels, and β-galactosidase (β-gal) staining, which confirmed the senescence. SKQ1 pre-treatment reversed these effects. ML385 lowered the Nrf2 protein levels and mRNA levels of its downstream targets. ML385 also abrogated the protective effects of SKQ1 against PM10 toxicity by preventing the restoration of cell viability and reduced oxidative stress. In conclusion, PM10 induces inflammation, reduces Nrf2 transcriptional activity, and causes DNA damage, leading to a senescence-like phenotype, which is prevented by SKQ1.

Consequences of exposure to particulate matter on the ocular surface: Mechanistic insights from cellular mechanisms to epidemiological findings

Exposure to air pollutants, especially in the case of particulate matter (PM), poses significant health risks throughout the body. The ocular surface is directly exposed to atmospheric PM making it challenging to avoid. This constant exposure makes the ocular surface a valuable model for investigating the impact of air pollutants on the eyes. This comprehensive review assembles evidence from across the spectrum, from in vitro and in vivo investigations to clinical studies and epidemiological studies, offering a thorough understanding of how PM10 and PM2.5 affect the health of the ocular surface. PM has been primarily found to induce inflammatory responses, allergic reactions, oxidative stress, DNA damage, mitochondrial impairment, and inhibit the proliferation and migration of ocular surface cells. In toto these effects ultimately lead to impaired wound healing and ocular surface damage. In addition, PM can alter tear composition. These events contribute to ocular diseases such as dry eye disease, blepharitis, conjunctivitis, keratitis, limbal stem cell deficiency and pterygium. Importantly, preexisting ocular conditions such as dry eye, allergic conjunctivitis, and infectious keratitis can be worsened by PM exposure. Adaptive responses may partially alleviate the mentioned insults, resulting in morphological and physiological changes that could be different between periods of short-term and long-term exposure. Particle size is not the only determinant of the ocular effect of PM, the composition and solubility of PM also play critical roles. Increasing awareness of how PM affects the ocular surface is crucial in the field of public health, and mechanistic insights of these adverse effects may provide guidelines for preventive and therapeutic strategies in dealing with a polluted environment.

Chlorantraniliprole induces mitophagy, ferroptosis, and cytokine homeostasis imbalance in grass carp (Ctenopharyngodon idella) hepatocytes via the mtROS-mitochondrial fission/fusion axis

Chlorantraniliprole (CAP) is a bis-amide pesticide used for pest control mainly in agricultural production activities and rice-fish co-culture systems. CAP residues cause liver damage in non-target organism freshwater fish. However, it is unclear whether CAP-exposure-induced liver injury in fish is associated with mitochondrial dysfunction-mediated mitophagy, ferroptosis, and cytokines. Therefore, we established grass carp hepatocyte models exposed to different concentrations of CAP (20, 40, and 80 μM) in vitro. MitoSOX probe, JC-1 staining, immunofluorescence double staining, Fe2+ staining, lipid peroxidation staining, qRT-PCR, and Western blot were used to verify the physiological regulatory mechanism of CAP induced liver injury. In the present study, the CAP-treated groups exhibited down-regulation of antioxidant-related enzyme activities and accumulation of peroxides. CAP treatment induced an increase in mitochondrial reactive oxygen species (mtROS) levels and altered expression of mitochondrial fission/fusion (Drp1, Fis1, Mfn1, Mfn2, and Opa1) genes in grass carp hepatocytes. In addition, mitophagy (Parkin, Pink1, p62, LC3II/I, and Beclin-1), ferroptosis (GPX4, COX2, ACSL4, FTH, and NCOA4), and cytokine (IFN-γ, IL-18, IL-17, IL-6, IL-10, IL-1β, IL-2, and TNF-α)-related gene expression was significantly altered. Collectively, these findings suggest that CAP exposure drives mitophagy activation, ferroptosis occurrence, and cytokine homeostasis imbalance in grass carp hepatocytes by triggering mitochondrial dysfunction mediated by the mtROS-mitochondrial fission/fusion axis. This study partly explained the physiological regulation mechanism of grass carp hepatocyte injury induced by insecticide CAP from the physiological and biochemical point of view and provided a basis for evaluating the safety of CAP environmental residues to non-target organisms.

Salidroside alleviates oxidative stress in dry eye disease by activating autophagy through AMPK-Sirt1 pathway

Dry eye disease (DED) is a multifactorial disease, and oxidative stress plays a crucial role in its pathogenesis. Recently, multiple studies have shown that upregulation of autophagy can protect the cornea from oxidative stress damage. The present study investigated the therapeutic effects of salidroside, the main component of Rhodiola crenulata, in both in vivo and in vitro dry eye models. The results showed that topical eye drop treatment with salidroside restored corneal epithelium damage, increased tear secretion, and reduced cornea inflammation in the DED mice. Salidroside activated autophagy through AMP-activated protein kinase (AMPK)-sirtuin-1 (Sirt1) signaling pathway, which promoted the nuclear translocation of nuclear factor erythroid-2-related factor 2 (Nrf2) and increased the expression of downstream antioxidant factors heme oxygenase-1 (HO-1) and NAD(P)H quinone dehydrogenase 1 (NQO1). This process restored antioxidant enzyme activity, reduced reactive oxygen species (ROS) accumulation, and alleviated oxidative stress. The application of autophagy inhibitor chloroquine and AMPK inhibitor Compound C reversed the therapeutic efficacy of salidroside, validating the above findings. In conclusion, our data suggest that salidroside is a promising candidate for DED treatment.