Perfluoroalkyl substance pollutants activate the innate immune system through the AIM2 inflammasome

Perfluoroalkyl and polyfluoroalkyl substances crossing the blood-joint barrier: Their occurrence and distribution in synovial fluid

Per- and polyfluoroalkyl substances (PFASs) have garnered considerable research attention due to their potential adverse effects on human health. Epidemiological studies have indicated a possible association between PFASs exposure and the prevalence of osteoarthritis (OA). However, the presence of PFASs in the synovial fluid of OA patients and the distribution of PFASs across the blood-joint barrier remains unreported. This study identified significant differences in PFASs profiles between patients and controls, with a markedly higher PFOS-to-PFOA ratio observed in patients. Additionally, the blood-joint transfer efficiency of PFOS was significantly greater in patients than in controls (0.75 vs. 0.53, p < 0.05). Furthermore, PFOS levels were elevated in patients with advanced OA compared to those in the early stages. Positive correlations were observed between synovial fluid PFOS and inflammatory markers C-reactive protein (CRP) and tumor necrosis factor-α (TNF-α), implying that inflammation may facilitate the distribution of PFOS across the joint barrier. This study represents the first documented evidence of the human joint exposure to PFASs and their blood-joint transfer abilities.

Integration of Animal, Population, and Toxicogenomic Evidence on the Hematotoxic and Immunosuppressive Effects of Environmental Exposure to PFAS Mixtures in Adolescents

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are emerging contaminants widely found in drinking water and food, potentially entering the human body through these sources. To investigate these effects, we simulated PFAS exposure doses in animal models, ranging from general population to occupational levels, and analyzed blood and spleen samples. Epidemiological studies linked PFAS exposure to immunosuppression and hematotoxicity, while toxicogenomic analyses validated the underlying biological mechanisms. PFAS exposure caused immunotoxic effects, including altered blood parameters and lymphocyte edema. Cellular abnormalities such as decreased cytoplasmic density, incomplete rough endoplasmic reticulum, chromatin condensation, lymphocyte nuclear shrinkage, and reduced mitochondrial cristae were observed. Epidemiological evidence revealed a dose-response relationship between mixed PFAS exposure and hematologic indices such as hematocrit (HCT), hemoglobin (HGB), platelet count (PLT), platelet-to-lymphocyte ratio (PLR), white blood cell count (WBC), monocyte percentage, and platelet large cell ratio (PLCR), with perfluorooctanoic acid (PFOA) playing a dominant role. Toxicogenomic analysis identified genes associated with platelets, anemia, and leukocyte function, linked to inflammation, Th17 cell differentiation, apoptosis, lipid metabolism, atherosclerosis, and JAK-STAT signaling. This study provides novel insights into the hematotoxicity and immunosuppressive effects of mixed PFAS exposure, emphasizing the need for PFAS substitution, removal, and policies addressing mixed exposures to protect public health.

Celecoxib as a potential treatment for hepatocellular carcinoma in populations exposed to high PFAS levels

Per- and polyfluoroalkyl substances (PFAS), including perfluorooctane sulfonate and perfluorooctanoic acid, are associated with adverse human effects. However, few studies have assessed the effects of PFAS mixtures on hepatocellular carcinoma (HCC). In this study, we systematically investigated the effects and underlying mechanisms of PFAS mixtures on the proliferation, migration, and invasion of HCC cells (JHH-7 and Li-7) in vitro using a combination of biological techniques and high-coverage untargeted metabolomics. A six day exposure to a 5 μM PFAS mixture significantly enhanced the malignant progression of HCC in vitro. Metabolomic analysis identified the upregulation of prostaglandin E2 (PGE2) as a key factor associated with these effects. This hypothesis was further validated using celecoxib, a PGE2 inhibitor, which reduced PGE2 levels in HCC cells, consequently slowing their migration and invasion. Additionally, mice treated with celecoxib exhibited reduced tumor volumes compared with those treated with PFAS alone. These results suggest that PFAS exposure enhances HCC malignancy through the PI3K/AKT signaling pathway via increased PGE2 production. In conclusion, a 5 μM PFAS mixture accelerates HCC proliferation and invasion; moreover, celecoxib demonstrates potential as a therapeutic agent that inhibits these effects.

Evidence of the occurrence, detection, and ecotoxicity studies of perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in aqueous environments

Perflorochemicals (PFCs), among which are the most commonly detected perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), are persistent emergent contaminants of concern in recent times. These compounds have been reported for their cytotoxicity, genotoxicity, carcinogenicity, immunotoxicity, and developmental toxicities. Meanwhile, they have been detected in diverse matrices such as soil, sediment, and, surprisingly, in serum and even breastmilk. Worrisomely, these compounds are detected in drinking water across the globe, aquaculture water, and other surface waters. Thus, it was important to appraise the studies conducted on PFOS and PFOA to provide an overview of the environmental status of contamination regarding them. The present review article sought to provide insights into the occurrence patterns and ecotoxic effects of both pollutants in the water ecosystems within five continents of the world. Based on the information gathered in this article, the ∑ P F O S concentration (ng/L) within the five continents is in the order Europe > Asia > Africa > North America > South America, while the ∑ P F O A level (ng/L) is in the order Europe > Asia > South America > Africa > North America. The study also investigated the previous works that have been conducted regarding the diverse elimination technologies employed for the removal of these pollutants from the aqueous environments, with plasma combined with surfactant process being the most efficient. Generally, studies on PFOS/PFOA are still scanty when compared to those on pharmaceuticals and personal care products (PPCPs), especially in North America. The information gathered in this study could be useful in establishing thresholds of PFOA and PFOS environmental levels and be adopted by appropriate authorities as safety guidelines.

Broflanilide induces zebrafish neurobehavioral defects by interfering with synaptic homeostasis

Broflanilide is a novel bisamide insecticide that is extensively used. Previous study reported that broflanilide induced neurotoxicity during zebrafish embryonic development, however, its behavior impact and the involved neural cell heterogeneous mechanism remains largely unknown. Here, we performed a series of neuro-behavior test for adult zebrafish that were exposed to 5 and 25 μg/L broflanilide for 30 days. We found that 25 μg/L broflanilide could induce abnormal locomotion and cognitive defect. These changes were accompanied by synaptic homeostasis inference (decreased number of synaptic knobs), and neuron loss. Simultaneously, a targeted metabolomic assay showed that the glutathione metabolism and GABAergic synapses in brain were significantly altered, indicating an altered synaptic transmission, which is consistent with the synaptic injury. Single-cell RNA sequencing of zebrafish brain showed changed cell composition after exposure, including a decreased ratio of neuron and oligodendrocyte, and an increased proportion of astrocytes. Meanwhile, genes involved in synaptic functional pathways were altered in neuron, astrocyte and oligodendrocytes, which partly explained the disruption of synaptic homeostasis. These findings reveal the long-term risk of broflanilide toward neural health of aquatic organisms and suggest an across-cell types transcriptional regulation in mediating the neurotoxicity.

Perfluoroalkyl substance pollutants disrupt microglia function and trigger transcriptional and epigenomic changes

Per- and polyfluoroalkyl substances (PFAS), commonly referred to as "forever chemicals", are widely utilized in various industries and consumer products worldwide. Their exposure has been associated with numerous diseases and malignancies, including neurodevelopmental and neurodegenerative disorders. However, the molecular mechanisms underlying PFAS-induced adverse effects on the central nervous system (CNS) remain poorly understood. In this study, we investigated the transcriptomic and epigenetic changes in microglia exposed to perfluorooctane sulfonate (PFOS), a prevalent PFAS compound. Our findings demonstrate that 24-hour PFOS exposure (25 and 50 µM) disrupts the microglial transcriptome and compromises their homeostatic state, marked by increased inflammation and impaired actin cytoskeleton remodeling. Comparative analysis with in vivo transcriptional states revealed that PFOS-exposed microglia exhibit gene expression profiles resembling those of aged microglia. Additionally, profiling of active chromatin regions uncovered significant alterations in the H3K27ac landscape in PFOS-exposed microglia. Notably, these epigenetic disruptions persisted even after PFOS withdrawal, with a subset of H3K27ac-enriched regions remaining altered, suggesting the presence of lasting epigenetic scars. Furthermore, transcription factor analysis implicated the AP-1 and TEAD families as potential upstream regulators connecting the altered chromatin landscape to transcriptomic changes. Collectively, these findings provide mechanistic insights into how PFOS exposure disrupts microglial function and highlight its potential role in exacerbating neurodegenerative processes.

Respiratory Health Impacts from Natural Disasters and Other Extreme Weather Events: The Role of Environmental Stressors on Asthma and Allergies

PURPOSE OF REVIEW

The frequency of natural disasters, other extreme weather events, and downstream emissions of emerging contaminants is increasing. One category of health outcome that is now experiencing increased prevalence due to these environmental threats is respiratory disease, specifically asthma and allergies; though a review summarizing current knowledge and research gaps has not been synthesized on this topic in recent years despite growing evidence.

RECENT FINDINGS

We identified recent literature that connects allergy/asthma with environmental events that are increasing in prevalence alongside natural disasters and other extreme weather events, including algal blooms, floods, heat stress, wildfires, and thunderstorms. Coinciding emissions of per-and polyfluoroalkyl substances (PFAS) and microplastics (MPs) are also discussed as downstream outcomes of these environmental events. Available evidence ranged according to environmental event/stressor type, with over 50 papers identified as relevant to this research scope in the last five years. Narrative synthesis of these papers highlighted exposure-disease linkages for stressors related to natural disasters, other extreme weather events, and downstream emissions of emerging contaminants with pulmonary asthma and allergy outcomes. Underlying biological mechanisms are beginning to be elucidated and include widespread inflammation in the lungs and changes in immune cell signaling and function across the pulmonary system. Take home points in this review pave the way for future investigations to better understand the impacts of these environmental events amongst the complex milieu of threats becoming increasingly prevalent worldwide.

Incidence of respiratory diseases associated with per- and polyfluoroalkyl substances (PFAS) in PM2.5: New evidence from a population-based survey of Pearl River Delta (PRD), China

Epidemiological studies have evinced that particulate matter (PM) is linked to respiratory diseases, but the relationship between the specific constituents of PM and respiratory diseases remains scarce. Here, we evaluated the relationship between PFAS in PM2.5 with respiratory diseases. In this study, from May 2016 to May 2018, we recruited 131,346 school-aged children and adolescents living in Pearl River Delta, Guangdong Province, China. Participants self-reported the respiratory diseases, including asthma, wheezing, phlegm, cough and rhinitis. Logistic regression and qg-comp models were used to analyze the relationship between PFAS exposure and respiratory diseases. We found several PFAS were significantly associated with higher prevalence of respiratory diseases. For instance, higher quintiles of PFSA exposure (Q2-Q4), as compared to Q1, were associated with greater odds of respiratory diseases: 1.35 (95 %CI: 1.23, 1.48) in Q2, 1.95 (95 %CI: 1.78, 2.14) in Q3 and 2.83 (95 %CI: 2.76, 3.11) in Q4. Furthermore, qg-comp model analysis revealed PFCA as the most important weight in respiratory diseases. Moreover, the effect estimates were higher in boys, older children (>12 years old) and overweight/obesity, indicating the vulnerability of these subpopulations. In summary, exposure to PFAS, a specific PM2.5 constituent, potentially increases the risk of respiratory diseases among school-aged children and adolescents.

Exposure-effect of PFOS and PFOA on lung function: An integrated approach with epidemiological, cellular, and animal studies

Perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are increasingly recognized for their adverse impact on human health, particularly on lung function. However, current research results are inconsistent and molecular mechanisms remain unclear, with no studies combining epidemiological, in vivo and in vitro investigations. Our population-based study revealed that PFOS and PFOA exposure is negatively associated with lung function. In vitro, PFOS and PFOA exposure significantly downregulated SP-B mRNA and protein levels, and SP-B expression was restored by overexpression of HSD17B1. PFOS induced hypermethylation and downregulated expression of HSD17B1 in tandem with SP-B. Notably, expression of SP-B was restored after treatment with demethyltransferase inhibitor. In vivo studies corroborated these findings, where PFOS exposure resulted in impaired lung function, histopathological changes, and decreased expression of SP-B and HSD17B1 in lung tissues. Our research demonstrates that PFOS downregulates SP-B expression by inducing hypermethylation and downregulating expression of HSD17B1, leading to impaired lung function.

Exposure to Long- and Short-Chain Per- and Polyfluoroalkyl Substances in Mice and Ovarian-Related Outcomes: An in Vivo and in Vitro Study

BACKGROUND

The extensive use of per- and polyfluoroalkyl substances (PFAS) has led to environmental contamination and bioaccumulation of these substances. Previous research linked PFAS exposure to female reproductive disorders, but the mechanism remains elusive. Further, most studies focused on legacy long-chain PFOA and PFOS, yet the reproductive impacts of other long-chain PFAS and short-chain alternatives are rarely explored.

OBJECTIVES

We investigated the effects of long- and short-chain PFAS on the mouse ovary and further evaluated the toxic mechanisms of long-chain perfluorononanoic acid (PFNA).

METHODS

A 3D in vitro mouse ovarian follicle culture system and an in vivo mouse model were used, together with approaches of reverse transcription-quantitative polymerase chain reaction (RT-qPCR), enzyme-linked immunosorbent assay (ELISA), RNA sequencing (RNA-seq), pharmacological treatments, in situ zymography, histology, in situ hybridization, analytical chemistry, and benchmark dose modeling (BMD). Using these approaches, a wide range of exposure levels (1 - 250 μ M ) of long-chain PFAS (PFOA, PFOS, PFNA) and short-chain PFAS (PFHpA, PFBS, GenX) were first tested in cultured follicles to examine their effects on follicle growth, hormone secretion, and ovulation. We identified 250 μ M as the most effective concentration for further investigation into the toxic mechanisms of PFNA, followed by an in vivo mouse exposure model to verify the accumulation of PFNA in the ovary and its ovarian-disrupting effects.

RESULTS

In vitro cultured ovarian follicles exposed to long- but not short-chain PFAS showed poorer gonadotropin-dependent follicle growth, ovulation, and hormone secretion in comparison with control follicles. RT-qPCR and RNA-seq analyses revealed significant alterations in the expression of genes involved in follicle-stimulating hormone (FSH)-dependent follicle growth, luteinizing hormone (LH)-stimulated ovulation, and associated regulatory pathways in the PFNA-exposed group in comparison with the control group. The PPAR agonist experiment demonstrated that a peroxisome proliferator-activated receptor gamma (PPAR γ ) antagonist could reverse both the phenotypic and genotypic effects of PFNA exposure, restoring them to levels comparable to the control group. Furthermore, in vivo experiments confirmed that PFNA could accumulate in ovarian tissues and validated the in vitro findings. The BMD, in vitro, and in vivo extrapolation analyses estimated follicular rupture as the most sensitive end point and that observed effects occurred in the range of human exposure to long-chain PFAS.

DISCUSSION

Our study demonstrates that long-chain PFAS, particularly PFNA, act as a PPAR γ agonist in granulosa cells to interfere with gonadotropin-dependent follicle growth, hormone secretion, and ovulation; and exposure to high levels of PFAS may cause adverse ovarian outcomes. https://doi.org/10.1289/EHP14876.

The toxicological effects of perfluorooctanoic acid (PFOA) exposure in large yellow croaker (Larimichthys crocea): exploring the relationship between liver damage and gut microbiota dysbiosis

Per- and polyfluoroalkyl substances (PFASs) are synthetic organofluorine compounds characterized by their persistence, toxicity, and bioaccumulative properties, rendering them substantial environmental contaminants. However, limited research has investigated the effects of a short-term low-concentration PFAS exposure on the hepatic and intestinal systems of marine fish. In this study, large yellow croaker was selected as the experimental subject to explore the toxic effects of exposure to 1000 ng/L PFOA after 3, 7, and 14 days, with a focus on liver and gut microbiota. The results demonstrated that a short-term exposure to PFOA induced significant histopathological damage in both liver and gut, with cumulative effects becoming more pronounced over time. Moreover, transcriptome analysis of the liver revealed that PFOA exposure significantly altered the expression of genes associated with lipid metabolism, inflammatory response, and cellular apoptosis. GO and KEGG functional enrichment analyses showed significant enrichment in the P53, NF-κB, MAPK, and PPAR signaling pathways. On the other hand, 16S rRNA gene sequencing demonstrated that PFOA exposure resulted in a decline in gut microbiota diversity, an increase in the abundance of potentially pathogenic bacteria (e.g. Proteobacteria), and a significant reduction in beneficial bacteria (Lactobacillus). These changes indicated gut microbiota dysbiosis. Correlation analysis between gut microbiota changes and potential liver damage indicators suggested an association between liver damage and gut microbiota dysbiosis. Furthermore, we propose a hypothetical model involving lipid accumulation-mediated mitochondrial oxidative stress and inflammation pathway activation, triggered by damage-associated molecular patterns (DAMPs) resulting from PFOA exposure. These findings offered valuable insights into the toxic effects of a short-term low-concentration PFOA on the hepatic and intestinal systems of large yellow croaker, and establish a connection between liver damage to gut microbiota dysbiosis after PFOA exposure.

Exposure to Sodium p-Perfluorous Nonenoxybenzenesulfonate Induces Renal Fibrosis in Mice by Disrupting Lysine Metabolism

Environmental exposure is one driving factor of chronic kidney disease (CKD), yet the intrinsic molecular mechanisms are largely unexplored. As a persistent chemical, perfluorooctanesulfonate (PFOS) is regulated due to a great potential to induce multiple diseases, including renal fibrosis, a major pathological characteristic of CKD. It is hypothesized that sodium p-perfluorous nonenoxybenzenesulfonate (OBS), a typical alternative to PFOS, may also induce renal fibrosis. We observed distinct renal fibrosis in mice exposed to OBS. Metabolomics analysis showed that Nα-acetyllysine was the primary metabolite biomarker, whose level decreased greatly due to its excessive consumption by lysyloxidase (LOX). This suppressed the miR-140-5p expression, promoting upregulation of fibroblast growth factor 9 (FGF9), which activated the PI3K/Akt signaling pathway through fibroblast growth factor receptor 3 (FGFR3), thereby enhancing proliferation and activation of fibroblasts. Supplement of Nα-acetyllysine upregulated miR-140-5p expression, reduced expressions of FGF9 and FGFR3, and eventually ameliorated OBS-induced renal fibrosis. Similarly, treatment with miR-140-5p agomir and PI3K/Akt signaling pathway inhibitor LY294002 attenuated OBS-induced renal fibrosis. Taken together, OBS caused renal fibrosis through the LOX-Nα-acetyllysine-miR-140-5p-FGF9-FGFR3-PI3K/Akt-Bad-Bcl-2-fibroblast axis. The results of this study reveal a specific molecular axis for OBS to induce renal fibrosis and call for concerns in supervising the application of OBS.

Mitochondrial damage-associated molecular patterns: New perspectives for mitochondria and inflammatory bowel diseases

Mitochondria are key regulators of inflammatory responses and mitochondrial dysfunction is closely linked to various inflammatory diseases. Increasing genetic and experimental evidence suggests that mitochondria play a critical role in inflammatory bowel disease (IBD). In the complex environment of the intestinal tract, intestinal epithelial cells (IECs) and their mitochondria possess unique phenotypic features, shaping each other and regulating intestinal homeostasis and inflammation through diverse mechanisms. Here, we focus on intestinal inflammation in IBD induced by mitochondrial damage-associated molecular patterns (mtDAMPs), which comprise mitochondrial components and metabolic products. The pathogenic mechanisms of mtDAMP signaling pathways mediated by two major mtDAMPs, mitochondrial DNA (mtDNA) and mitochondrial reactive oxygen species (mtROS), are discussed.

Mitochondrial DNA in Exercise-Mediated Innate Immune Responses

Mitochondria are considered as "the plant of power" with cells for a long time. However, recent researches suggest that mitochondria also take part in innate immune response to a great extent. Remarkably, mtDNA was reported to have immunnostimulatory potential in 2004. Since then, there has been rapid growth in understanding the role of mtDNA in innate immune. The mtDNA is released into cytosol, extracellular environment, or circulating blood through BAK/BAX pore, mPTP, and GSDMD pore upon mitochondrial damage, where it is recognized by PRRs including TLR9, cGAS, and NLRP3, thereby triggering innate immune response. On the other hand, regular exercise has been recognized as an effective intervention strategy for innate immune response. Some studies show that chronic moderate-intensity endurance exercise, resistance training, HIIT, and moderate-intensity acute exercise enhance mitochondrial function by promoting mtDNA transcription and replication, thus blunting the abnormal release of mtDNA and excessive innate immune response. On the contrary, high-intensity acute exercise elicits the opposite effect. Nevertheless, only a very small body of research by far has been performed to illustrate the impact of exercise on mtDNA-driven innate immune response, and an overall review is lacking. In light of these, we summarize the current knowledge on the mechanism mediating the release of mtDNA, the role of mtDNA in innate immune response and the influence of exercise on mtDNA leakage, hoping to pave the way to investigate new diagnostic and therapeutic approaches for immunopathies.

Impact of PFOS Exposure on Murine Fetal Hematopoietic Stem Cells, Associated with Intrauterine Metabolic Perturbation

This study hypothesized that perfluorooctanesulfonate (PFOS) exposure disrupts maternal-fetal metabolism, affecting fetal liver hematopoietic stem cell (FL-HSC) development. Pregnant mice received PFOS (0.3 and 3 μg/g bw) and were sacrificed on gestation day 14.5. Metabolomic analysis of maternal plasma revealed disruptions in steroid hormone, purine, carbohydrate, and amino acid metabolism, which aligned with the enriched pathways in amniotic fluid (AF). FL analysis indicated increased purine metabolism and disrupted glucose and amino acid metabolism. FL exhibited higher levels of polyunsaturated fatty acids, glycolytic and TCA metabolites, and pro-inflammatory cytokine IL-23, crucial for hematopoiesis regulation. Transcriptomic analysis of FL-HSCs revealed disturbances in the PPAR signaling pathway, pyruvate metabolism, oxidative phosphorylation, and amino acid metabolism, correlating with FL metabolic changes. Metabolomic analysis indicated significant rises in glycerophospholipid and vitamin B6 metabolism related to HSC expansion and differentiation. Flow cytometric analysis confirmed increased HSC populations and progenitor activation for megakaryocyte, erythrocyte, and lymphocyte lineages. The CFU assay showed a significant increase in BFU-E and CFU-G, but a decrease in CFU-GM in FL-HSCs from the H-PFOS group, indicating altered differentiation potential. These findings provide for the first time insights into the effects of PFOS on maternal-fetal metabolism and fetal hematopoiesis, highlighting implications for pollution-affected immune functions.

Association of Per- and Polyfluoroalkyl Substance Exposure with Coronary Stenosis and Prognosis in Acute Coronary Syndrome

Per- and polyfluoroalkyl substances (PFAS) have been associated with an increased risk of acute coronary syndromes (ACS), but the influence on the degree of coronary stenosis and prognosis is unclear. This study enrolled 571 newly diagnosed ACS cases and investigated the association of 12 PFAS with coronary stenosis severity and prognosis. Coronary stenosis was assessed via Gensini score (GS) and number of lesioned vessels (LVN). Prognosis was estimated by tracking major adverse cardiovascular events (MACE). Statistical analyses included ordered logistic regression, Cox regression, threshold effect models, Bayesian kernel machine regression, and quantile g-computation models. The adverse outcome pathway (AOP) framework was applied to reveal the underlying mechanism. The results showed positive association between perfluorooctanesulfonic acid (PFOS) and coronary stenosis, with an odds ratio (95% confidence interval, CI) of 1.33 (1.06, 1.67) for GS and 1.36 (1.08, 1.71) for LVN. PFOS significantly increased the incidence of poor prognosis, with hazard ratios (95% CI) of 1.96 (1.34, 2.89) for MACE. Threshold effects were observed for PFAS on coronary stenosis and prognosis, with PFOS thresholds of 4.65 ng/mL for GS, 4.54 ng/mL for LVN, and 5.14 ng/mL for MACE, and 5.03 ng/mL for nonfatal myocardial infarction. PFAS mixture exposure increased the occurrence of MACE and nonfatal myocardial infarction. The AOP framework shows that PFAS may impact protein binding, the cytoskeleton, multicellular biological processes, and heart function. In summary, our study revealed the adverse effects of PFAS on the degree of coronary stenosis and prognosis in ACS and identified potentially relevant molecular loci.

Effects of mixed exposure to PFAS on adolescent non-alcoholic fatty liver disease: Integrating evidence from human cohorts, toxicogenomics, and animal models to uncover mechanisms and potential target sites

Extensive evidence suggests a correlation between environmental pollutants, specifically perfluoroalkyl and polyfluoroalkyl substances (PFAS) and non-alcoholic fatty liver disease (NAFLD). This study aims to investigate the association and underlying mechanisms of PFAS-induced NAFLD in adolescents by employing a comprehensive approach of population-based studies, toxicogenomics, and animal models. A total of 2014 freshmen from Dali University were recruited for this study, with 1694 participants undergoing serum testing for PFAS exposure. Additionally, Comparative Toxicogenomics Database analysis and PFAS exposure experiments were conducted by orally administering PFAS to 8-week-old adult C57/6 J mice for 28 days. Epidemiological analysis of the adolescent cohort revealed that perfluorohexanesulfonic acid and perfluorooctanoic acid are significant risk factors for NAFLD in adolescents. Toxicogenomic analysis revealed that the negative regulation of gap junction assembly and glutathione derivative biosynthesis contributes to NAFLD development. Animal model studies further demonstrated that combined PFAS exposure led to pathological changes in hepatocytes, including inflammation and steatosis, elevated liver enzymes, cholestasis, and bile canalicular blockage. This study reveals that PFAS exposure serves as a significant risk factor for hepatic steatosis/NAFLD in adolescents. The activation of cytochrome P4502E1 and glutathione S-transferase A1 signaling highlights new molecular targets for PFAS-induced disruptions in hepatic lipid metabolism.

Hidden link between endocrine-disrupting chemicals and pediatric obesity

The increasing prevalence of pediatric obesity has emerged as a significant public health concern. Among various contributing factors, exposure to endocrine-disrupting chemicals (EDCs) has gained recognition for its potential role. EDCs, including bisphenols, phthalates, per- and polyfluoroalkyl substances, polycyclic aromatic hydrocarbons, and organochlorines, disrupt hormonal regulation and metabolic processes, contributing to alterations in fat storage, appetite regulation, and insulin sensitivity. This study offers a comprehensive review of the current research linking EDC exposure to pediatric obesity by integrating the findings from experimental and epidemiological studies. It also addresses the complexities of interpreting this evidence in the context of public health, highlighting the urgent need for further research.

Association Between Per- and Polyfluoroalkyl Substances and All-Cause Mortality in Diabetic Patients: Insights from a National Cohort Study and Toxicogenomic Analysis

Per- and polyfluoroalkyl substances (PFAS) are a group of environmental contaminants associated with various health risks; however, their relationship with all-cause mortality in individuals with diabetes remains unclear. A total of 1256 participants from the National Health and Nutrition Examination Survey (NHANES) were included to explore the association between seven PFAS compounds and all-cause mortality in diabetic patients. Preliminary logistic regression identified three PFAS compounds (perfluorooctanoic acid [PFOA], perfluorooctane sulfonic acid [PFOS], and 2-(N-methyl-PFOSA) acetate acid [MPAH]) as significantly associated with mortality in the diabetic population. The optimal cut-off values for PFOS, PFOA, and MPAH were determined using the X-tile algorithm, and participants were categorized into high- and low-exposure groups. Kaplan-Meier survival curves and multivariable Cox proportional hazards regression models were used to assess the relationship between PFAS levels and mortality risk. The results showed that high levels of PFOS were significantly associated with increased all-cause mortality risk in diabetic patients (hazard ratio [HR]: 1.55, 95% confidence interval [CI]: 1.06-2.29), while PFOA and MPAH showed no significant associations. To explore mechanisms underlying the PFOS-mortality link, toxicogenomic analysis identified 95 overlapping genes associated with PFOS exposure and diabetes-related mortality using the Comparative Toxicogenomics Database (CTD) and GeneCards. Functional enrichment analysis revealed key biological processes, such as glucose homeostasis and response to peptide hormone, with pathways including the longevity regulating pathway, apoptosis, and p53 signaling pathway. Protein-protein interaction network analysis identified 10 hub genes, and PFOS was found to upregulate or downregulate their mRNA expression, protein activity, or protein expression, with notable effects on mRNA levels. These findings suggest that PFOS exposure contributes to increased mortality risk in diabetic patients through pathways related to glucose metabolism, apoptosis, and cellular signaling. Our study provides new insights into the association between PFAS and all-cause mortality in diabetes, highlighting the need for large-scale cohort studies and further in vivo and in vitro experiments to validate these findings.

GSDMD-mediated pyroptosis: molecular mechanisms, diseases and therapeutic targets

Pyroptosis is a regulated form of inflammatory cell death in which Gasdermin D (GSDMD) plays a central role as the key effector molecule. GSDMD-mediated pyroptosis is characterized by complex biological features and considerable heterogeneity in its expression, mechanisms, and functional outcomes across various tissues, cell types, and pathological microenvironments. This heterogeneity is particularly pronounced in inflammation-related diseases and tumors. In the context of inflammatory diseases, GSDMD expression is typically upregulated, and its activation in macrophages, neutrophils, T cells, epithelial cells, and mitochondria triggers both pyroptotic and non-pyroptotic pathways, leading to the release of pro-inflammatory cytokines and exacerbation of tissue damage. However, under certain conditions, GSDMD-mediated pyroptosis may also serve a protective immune function. The expression of GSDMD in tumors is regulated in a more complex manner, where it can either promote immune evasion or, in some instances, induce tumor cell death. As our understanding of GSDMD's role continues to progress, there have been advancements in the development of inhibitors targeting GSDMD-mediated pyroptosis; however, these therapeutic interventions remain in the preclinical phase. This review systematically examines the cellular and molecular complexities of GSDMD-mediated pyroptosis, with a particular emphasis on its roles in inflammation-related diseases and cancer. Furthermore, it underscores the substantial therapeutic potential of GSDMD as a target for precision medicine, highlighting its promising clinical applications.

PFOS-Induced Perturbations in Trophoblast Functions through the Oip5os1/miR-155/Rnd3 Axis in PE

The widespread use of perfluorooctanesulfonic acid (PFOS) has raised concerns regarding its potential on pregnant women, particularly in relation to the development of pre-eclampsia (PE). This study investigates the impact of PFOS exposure on the LncRNA/Rnd3 axis in pregnant mice and its association with trophoblast cell functions in PE. Bioinformatics analysis revealed PFOS-related gene alterations in PE, with pathways enriched in apoptotic signaling and cytokine interactions. Experimental findings showed the downregulation of Oip5os1 and Rnd3, along with the upregulation of miR-155, affecting trophoblast behavior. Animal experiments confirmed that PFOS-induced gene expression changes are linked to PE progression. PFOS exposure impairs trophoblast proliferation and migration via the Oip5os1/miR-155/Rnd3 axis, contributing to PE development.

Mitochondrial DNA leakage: underlying mechanisms and therapeutic implications in neurological disorders

Mitochondrial dysfunction is a pivotal instigator of neuroinflammation, with mitochondrial DNA (mtDNA) leakage as a critical intermediary. This review delineates the intricate pathways leading to mtDNA release, which include membrane permeabilization, vesicular trafficking, disruption of homeostatic regulation, and abnormalities in mitochondrial dynamics. The escaped mtDNA activates cytosolic DNA sensors, especially cyclic gmp-amp synthase (cGAS) signalling and inflammasome, initiating neuroinflammatory cascades via pathways, exacerbating a spectrum of neurological pathologies. The therapeutic promise of targeting mtDNA leakage is discussed in detail, underscoring the necessity for a multifaceted strategy that encompasses the preservation of mtDNA homeostasis, prevention of membrane leakage, reestablishment of mitochondrial dynamics, and inhibition the activation of cytosolic DNA sensors. Advancing our understanding of the complex interplay between mtDNA leakage and neuroinflammation is imperative for developing precision therapeutic interventions for neurological disorders.

Per- and Polyfluoroalkyl Substances and Female Health Concern: Gender-based Accumulation Differences, Adverse Outcomes, and Mechanisms

The deleterious health implications of perfluoroalkyl and polyfluoroalkyl substances (PFAS) are widely recognized. Females, in contrast to males, exhibit unique pathways for PFAS exposure and excretion, leading to complex health outcomes. The health status of females is largely influenced by hormone-related processes. PFAS have been reported to be associated with various aspects of female health, including reproductive system disorders and pregnancy-related diseases. In this article, we provide insights into the correlations between PFAS and female-prevalent diseases. Current epidemiological and toxicological evidence has demonstrated that the adverse effects of PFAS on the health of the female reproductive system are primarily attributed to the disruption of the hypothalamic-pituitary-gonadal (HPG) axis and hormonal homeostasis. However, these findings do not sufficiently elucidate the intricate associations between PFAS and specific diseases. Furthermore, autoimmune disorders, another category that is more prevalent in women compared to men, require additional investigation. Immune biomarkers pertinent to autoimmune disorders have been observed to be influenced by PFAS exposure, although epidemiological evidence is insufficient to substantiate these relations. Further thorough exploration encompassing epidemiological and toxicological studies is essential to elucidating the inherent influence of PFAS on human pathologies. Additionally, comprehensive investigations into female health issues beyond their reproductive functions is essential.

Arginine Metabolism Reprogramming in Perfluorooctanoic Acid (PFOA)-Induced Liver Injury

Perfluorooctanoic acid (PFOA) is a persistent pollutant that has gained worldwide attention, owing to its widespread presence in the environment. Previous studies have reported that PFOA upregulates lipid metabolism and is associated with liver injury in humans. However, when the fatty acid degradation pathway is activated, lipid accumulation still occurs, suggesting the presence of unknown pathways and mechanisms that remain to be elucidated. In this study, adult C57BL/6N mice were exposed to PFOA at 0.1, 1, and 10 mg/kg/day. Using integrated metabolomics and transcriptomics, it was uncovered that arginine metabolism was differentially downregulated in all three groups. In vitro studies confirmed the downregulation of arginine metabolism in MIHA cell lines treated with PFOA. Supplementation of arginine could effectively rescue liver injury and downregulate the chemokine levels caused by PFOA. This finding highlights the contribution of arginine metabolism in maintaining liver health following PFOA exposure and suggests potential mechanisms of metabolic and immune modulation.

Short-Chain Chlorinated Paraffins May Induce Ovarian Damage in Mice via AIM2- and NLRP12-PANoptosome

Humans may intake 0.02 mg/kg/day of short-chain chlorinated paraffins (SCCPs), and no study is available on mammalian ovarian damage caused by low-level SCCPs. In this study, four groups of 5-week-old female Institute of Cancer Research (ICR) mice were orally administered 0, 0.01, 0.1, and 1.0 mg/kg/day SCCPs for 21 consecutive days, and serum and ovaries were collected 20 h after the last SCCPs-administration. SCCPs at ≥0.1 mg/kg/day were found to reduce follicle counts at each stage, induce dose-dependent oxidative stress in mice, and lower serum E2 and ovarian anti-Müllerian hormone levels. The data indicated that cellular PANoptosis increased in the ovaries of all SCCP-treated mice. Furthermore, AIM2- and NLRP12-PANoptosome gene and protein levels were considerably elevated. Female germline stem cells (FGSCs) in the cortical portion of the ovary exhibited substantial damage in all SCCP groups, additionally, the expression of FGSC marker genes and major marker proteins was diminished in the ovaries. Oral administration of SCCPs with 0.01, 0.1, and 1.0 mg/kg/day to mice resulted in PANoptosis of the ovaries. Therefore, it was suggested that the oral administration of ≥0.1 mg/kg/day of SCCPs suppressed ovarian function, which may be attributed to the fact that SCCPs induced the generation of AIM2- and NLRP12-PANoptosome in ovary cells.

Molecular mechanisms of emerging inflammasome complexes and their activation and signaling in inflammation and pyroptosis

Inflammasomes are multi-protein complexes that assemble within the cytoplasm of mammalian cells in response to pathogen-associated molecular patterns (PAMPs) or damage-associated molecular patterns (DAMPs), driving the secretion of the pro-inflammatory cytokines IL-1β and IL-18, and pyroptosis. The best-characterized inflammasome complexes are the NLRP3, NAIP-NLRC4, NLRP1, AIM2, and Pyrin canonical caspase-1-containing inflammasomes, and the caspase-11 non-canonical inflammasome. Newer inflammasome sensor proteins have been identified, including NLRP6, NLRP7, NLRP9, NLRP10, NLRP11, NLRP12, CARD8, and MxA. These inflammasome sensors can sense PAMPs from bacteria, viruses and protozoa, or DAMPs in the form of mitochondrial damage, ROS, stress and heme. The mechanisms of action, physiological relevance, consequences in human diseases, and avenues for therapeutic intervention for these novel inflammasomes are beginning to be realized. Here, we discuss these emerging inflammasome complexes and their putative activation mechanisms, molecular and signaling pathways, and physiological roles in health and disease.

DAMP-ing IBD: Extinguish the Fire and Prevent Smoldering

In inflammatory bowel diseases (IBD), the most promising therapies targeting cytokines or immune cell trafficking demonstrate around 40% efficacy. As IBD is a multifactorial inflammation of the intestinal tract, a single-target approach is unlikely to solve this problem, necessitating an alternative strategy that addresses its variability. One approach often overlooked by the pharmaceutically driven therapeutic options is to address the impact of environmental factors. This is somewhat surprising considering that IBD is increasingly viewed as a condition heavily influenced by such factors, including diet, stress, and environmental pollution-often referred to as the "Western lifestyle". In IBD, intestinal responses result from a complex interplay among the genetic background of the patient, molecules, cells, and the local inflammatory microenvironment where danger- and microbe-associated molecular patterns (D/MAMPs) provide an adjuvant-rich environment. Through activating DAMP receptors, this array of pro-inflammatory factors can stimulate, for example, the NLRP3 inflammasome-a major amplifier of the inflammatory response in IBD, and various immune cells via non-specific bystander activation of myeloid cells (e.g., macrophages) and lymphocytes (e.g., tissue-resident memory T cells). Current single-target biological treatment approaches can dampen the immune response, but without reducing exposure to environmental factors of IBD, e.g., by changing diet (reducing ultra-processed foods), the adjuvant-rich landscape is never resolved and continues to drive intestinal mucosal dysregulation. Thus, such treatment approaches are not enough to put out the inflammatory fire. The resultant smoldering, low-grade inflammation diminishes physiological resilience of the intestinal (micro)environment, perpetuating the state of chronic disease. Therefore, our hypothesis posits that successful interventions for IBD must address the complexity of the disease by simultaneously targeting all modifiable aspects: innate immunity cytokines and microbiota, adaptive immunity cells and cytokines, and factors that relate to the (micro)environment. Thus the disease can be comprehensively treated across the nano-, meso-, and microscales, rather than with a focus on single targets. A broader perspective on IBD treatment that also includes options to adapt the DAMPing (micro)environment is warranted.

Increased perfluorooctanoic acid accumulation facilitates the migration and invasion of lung cancer cells via remodeling cell mechanics

Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are widely used in industrial and household products, raising serious concerns due to their environmental persistence and mobility. Epidemiological studies have reported potential carcinogenic risks of PFAS based on their widespread occurrence and population exposure. In this study, we observed that perfluorooctanoic acid (PFOA), a common PFAS, functions as a mechanical regulator in lung cancer cells. PFOA exposure reduces cell stiffness, thereby decreasing cell adhesion and enhancing immune evasion, ultimately exacerbating tumor metastasis. In various lung cancer models, more aggressive tumor metastases have been observed in the PFOA exposure group. Additionally, serum PFOA levels in patients with advanced lung adenocarcinoma were significantly higher than those in patients with early-stage disease. Mechanistically, the interaction between PFOA and transmembrane integrins in cancer cells triggers changes in cellular mechanical properties, leading to the reorganization of the cytoskeleton, and activation of the intracellular FAK-PI3K-Akt signaling pathway. Our findings demonstrate that in individuals with lung adenocarcinoma, PFOA can increase the risk of cancer metastasis even at daily exposure levels.

The ENDOMIX perspective: how everyday chemical mixtures impact human health and reproduction by targeting the immune system†

Endocrine-disrupting chemicals are natural and synthetic compounds found ubiquitously in the environment that interfere with the hormonal-immune axis, potentially impacting human health and reproduction. Exposure to endocrine-disrupting chemicals has been associated with numerous health risks, such as neurodevelopmental disorders, metabolic syndrome, thyroid dysfunction, infertility, and cancers. Nevertheless, the current approach to establishing causality between these substances and disease outcomes has limitations. Epidemiological and experimental research on endocrine-disrupting chemicals faces challenges in accurately assessing chemical exposure and interpreting non-monotonic dose response curves. In addition, most studies have focused on single chemicals or simple mixtures, overlooking complex real-life exposures and mechanistic insights, in particular regarding endocrine-disrupting chemicals' impact on the immune system. The ENDOMIX project, funded by the EU's Horizon Health Program, addresses these challenges by integrating epidemiological, risk assessment, and immunotoxicology methodologies. This systemic approach comprises the triangulation of human cohort, in vitro, and in vivo data to determine the combined effects of chemical mixtures. The present review presents and discusses current literature regarding human reproduction in the context of immunotolerance and chemical disruption mode of action. It further underscores the ENDOMIX perspective to elucidate the impact of endocrine-disrupting chemicals on immune-reproductive health.

Per- and polyfluoroalkyl substances alter innate immune function: evidence and data gaps

Per- and polyfluoroalkyl substances (PFASs) are a large class of compounds used in a variety of processes and consumer products. Their unique chemical properties make them ubiquitous and persistent environmental contaminants while also making them economically viable and socially convenient. To date, several reviews have been published to synthesize information regarding the immunotoxic effects of PFASs on the adaptive immune system. However, these reviews often do not include data on the impact of these compounds on innate immunity. Here, current literature is reviewed to identify and incorporate data regarding the effects of PFASs on innate immunity in humans, experimental models, and wildlife. Known mechanisms by which PFASs modulate innate immune function are also reviewed, including disruption of cell signaling, metabolism, and tissue-level effects. For PFASs where innate immune data are available, results are equivocal, raising additional questions about common mechanisms or pathways of toxicity, but highlighting that the innate immune system within several species can be perturbed by exposure to PFASs. Recommendations are provided for future research to inform hazard identification, risk assessment, and risk management practices for PFASs to protect the immune systems of exposed organisms as well as environmental health.

Microglial mitochondrial DNA release contributes to neuroinflammation after intracerebral hemorrhage through activating AIM2 inflammasome

Intracerebral hemorrhage (ICH) is a severe disease that often leads to disability and death. Neuroinflammatory response is a key causative factor of early secondary brain injury after ICH. AIM2 is a DNA-sensing protein that recognizes cytosolic double-stranded DNA and take a significant part in neuroinflammation. Mitochondrial DNA participates in the translation of proteins such as the respiratory chain in the mitochondria. Whether mtDNA is involved in forming AIM2 inflammasome after ICH remains unclear. We used mice to construct ICH model in vivo and we used BV2 microglial cells treated with oxyhemoglobin to simulate ICH in vitro. Following lentiviral transfection to overexpress AIM2 antagonist P202, a notable decrease was observed in the levels of AIM2 inflammasome-associated proteins, leading to a reduction in dead neurons surrounding the hematoma and an enhancement in long-term and short-term behavior of neurological deficits. We further explored whether mtDNA took part in the AIM2 activation after ICH. The cytosolic mtDNA level was down-regulated by the mitochondrial division protector Mdivi-1 and up-regulated by transfection of mtDNA into cytoplasm. We found the expression level of AIM2 inflammasome-related proteins and inflammatory cytokines release were regulated by the cytosolic mtDNA level. In conclusion, after ICH, the mtDNA content in the cytoplasm of microglia around the hematoma rises, causing AIM2 inflammation leading to neuronal apoptosis, which leads to neurological deficits in mice. On the other hand, P202 was able to block inflammatory vesicle activation and improve neurological function by preventing the interaction between AIM2 protein and mitochondrial DNA.

Exposure to polystyrene microplastics during lactational period alters immune status in both male mice and their offspring

The widespread use of microplastics and their harmful effects on the environment have emerged as serious concerns. However, the effect of microplastics on the immune system of mammals, particularly their offspring, has received little attention. In this study, polystyrene microplastics (PS-MPs) were orally administered to male mice during lactation. Flow cytometry was used to assess the immune cells in the spleens of both adult male mice and their offspring. The results showed that mice exposed to PS-MPs exhibited an increase in spleen weight and an elevated number of B and regulatory T cells (Tregs), irrespective of dosage. Furthermore, the F1 male offspring of the PS-MPs-exposed group had enlarged spleens; an increased number of B cells, T helper cells (Th cells), and Tregs; and an elevated ratio of T helper cells 17 (Th17 cells) to Tregs and T helper cells 1 (Th1 cells) to T helper cells 2 (Th2 cells). These results suggested a pro-inflammatory state in the spleen. In contrast, in the F1 female offspring exposed to PS-MPs, the changes in splenic immune cells were less pronounced. In the F2 generation of mice with exposed to PS-MPs, minimal alterations were observed in spleen immune cells and morphology. In conclusion, our study demonstrated that exposure to real human doses of PS-MPs during lactation in male mice altered the immune status, which can be passed on to F1 offspring but is not inherited across generations.

SAP130 mediates crosstalk between hepatocyte ferroptosis and M1 macrophage polarization in PFOS-induced hepatotoxicity

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant widely utilized in industrial manufacturing and daily life, leading to significant environmental accumulation and various public health issues. This study aims to characterize spliceosome-associated protein 130 (SAP130) as a key mediator of crosstalk between hepatocytes and macrophages, elucidating its role in PFOS-induced liver inflammation. The data demonstrate that PFOS exposure induces ferroptosis in mouse liver and AML12 cells. During ferroptosis, SAP130 is released from injured hepatocytes into the microenvironment, binding to macrophage-inducible C-type lectin (Mincle) and activating the Mincle/Syk signaling pathway in macrophages, ultimately promoting M1 polarization and exacerbating liver injury. Treatment with the ferroptosis inhibitor Ferrostatin-1 reduces SAP130 release, inhibits Mincle/Syk signaling activation, and mitigates inflammatory response. Furthermore, siSAP130 suppresses the activation of the Mincle signaling pathway and M1 polarization in BMDM cells. Conversely, treatment with the ferroptosis agonist Erastin enhances paracrine secretion of SAP130 and exacerbates inflammation. These findings emphasize the significance of hepatocyte-macrophage crosstalk as a critical pathway for PFOS-induced liver injury in mice while highlighting SAP130 as a pivotal regulator of ferroptosis and inflammation, thereby elucidating the potential mechanism of PFOS-induced liver injury.

Pyroptosis in asthma: inflammatory phenotypes, immune and non-immune cells, and novel treatment approaches

Pyroptosis is a form of inflammatory programmed cell death, and is activated by pathogen infections or endogenous danger signals. The canonical pyroptosis process is characterized by the inflammasome (typically NLRP3)-mediated activation of caspase-1, which in turn cleaves and activates IL-1β and IL-18, as well as gasdermin D, which is a pore-forming executor protein, leading to cell membrane rupture, and the release of proinflammatory cytokines and damage-associated molecular pattern molecules. Pyroptosis is considered a part of the innate immune response. A certain level of pyroptosis can help eliminate pathogenic microorganisms, but excessive pyroptosis can lead to persistent inflammatory responses, and cause tissue damage. In recent years, pyroptosis has emerged as a crucial contributor to the development of chronic inflammatory respiratory diseases, such as asthma. The present study reviews the involvement of pyroptosis in the development of asthma, in terms of its role in different inflammatory phenotypes of the disease, and its influence on various immune and non-immune cells in the airway. In addition, the potential therapeutic value of targeting pyroptosis for the treatment of specific phenotypes of asthma is discussed.

Clinical, histological, molecular, and toxicokinetic renal outcomes of per-/polyfluoroalkyl substances (PFAS) exposure: Systematic review and meta-analysis

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals present in the environment that can negatively affect health. Kidney is the major target organ of PFAS exposure, yet the renal impact of PFAS is not completely understood. Here we review the effects of PFAS exposure on kidney health to identify gaps in our understanding and mark potential avenues for future research.

METHODS

PubMed and SCOPUS databases were searched for studies that examined the association between PFAS exposure and kidney-related outcomes. We included all epidemiological, animal, and cell studies and categorized outcomes into four categories: clinical, histological, molecular and toxicokinetic.

RESULTS

We identified 169 studies, including 51 on clinical outcomes, 28 on histological changes, 42 on molecular mechanisms, and 68 on toxicokinetics. Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) exposure were associated with kidney dysfunction, chronic kidney diseases, and increased risk of kidney cancer. Various histological changes were reported, especially in tubular epithelial cells, and the etiology of PFAS-induced kidney injury included various molecular mechanisms. Although PFOA and PFOS are not considered genotoxic, they exhibit several characteristics of carcinogens. Toxicokinetics of PFOA and PFOS differed significantly between species, with renal elimination influenced by various factors such as sex, age, and structure of the compound.

CONCLUSION

Evidence suggests that PFAS, especially PFOA and PFOS, negatively affects kidney health, though gaps in our understanding of such effects call for further research.

Review of Excessive Cytosolic DNA and Its Role in AIM2 and cGAS-STING Mediated Psoriasis Development

In psoriasis, keratinocytes are triggered by factors, such as infection or tissue damage, to release DNA, which thereby activates plasmacytoid dendritic cells and macrophages to induce inflammation, thickened epidermis, and parakeratosis. The recognition of double-stranded (ds)DNA facilitates the activation of cytoplasmic DNA sensors absent in melanoma 2 (AIM2) inflammasome assembly and cyclic guanosine monophosphate adenosine monophosphate (cGAMP) synthase (cGAS) - stimulator of interferon gene (STING) pathway, both of which play a pivotal role in mediating the inflammatory response and driving the progression of psoriasis. Additionally, secreted proinflammatory cytokines can stimulate further DNA release from keratinocytes. Notably, the activation of AIM2 and cGAS-STING signaling pathways also mediates programmed cell death, potentially enhancing DNA overproduction. As a result, excessive DNA can activate these pathways, amplifying persistent inflammatory responses that contribute to the maintenance of psoriasis. Several studies have validated that targeting DNA and its mediated activation of AIM2 and cGAS-STING offers promising therapeutic strategies for psoriasis. Here, we postulate a hypothesis that excessive cytosolic DNA can activate AIM2 and cGAS-STING, mediating inflammation and programmed cell death, ultimately fostering DNA accumulation and contributing to the development of psoriasis.

Per and poly-fluoroalkyl substances and respiratory health in an Inuit community

BACKGROUND

Concentrations of plasma per and poly-fluoroalkyl substances (PFAS) are elevated in the Inuit population of Nunavik and may be causing adverse health effects. Respiratory health outcomes have been associated with PFAS, but have not been explored in Inuit communities. The aim of the study was to examine the association between PFAS and respiratory health outcomes, and the moderating role of nutritional biomarkers.

METHODS

We included up to 1298 participants of the Qanuilirpitaa? 2017 survey aged 16-80 years. Generalized regression models were used to estimate the associations between six individual PFAS congeners and four self-reported symptoms, four spirometry measures, and physician-diagnosed asthma. Outcomes associated with PFAS from single chemical models were further explored using Bayesian Kernel Machine Regression (BKMR). The modifying effect of n-3 PUFA in red blood cell quartiles and vitamin D deficiency were examined on the associations between PFAS and respiratory outcomes.

RESULTS

PFNA and PFOS were associated with asthma (odds ratio (OR) 1.61, 95% confidence interval (CI) 1.12, 2.32; OR 1.45 95% CI 1.04, 2.03). PFOA, PFNA, PFDA and PFHxS were associated with a decrease in the ratio between the forced expiratory volume in the first second and forced vital capacity (FEV1/FVC). No associations were observed with self-reported respiratory symptoms. No associations were observed between a PFAS mixture and asthma. Some associations were modified by nutritional factors, namely, stronger associations between PFOA and PFHxS and asthma with lower n-3 PUFA levels and stronger associations between PFDA, PFUnDA and PFOS and FEV1/FVC with vitamin D deficiency.

CONCLUSION

These findings add to the growing literature on the impacts of PFAS on respiratory health, and the importance of their global regulation. Associations were modified by nutritional factors pointing to the nutritional value of traditional Inuit foods.

Developmental perfluorooctane sulfonic acid exposure exacerbates house dust mite induced allergic responses in adult mice

Perfluorooctane sulfonic acid (PFOS) is a long-chain per- and polyfluoroalkyl substance (PFAS), a persistent organic pollutant, which has been used in aqueous film-forming foams. Emerging epidemiological evidence indicates a significant body burden of PFOS is observed in the lungs. Furthermore, developmental PFOS exposure dysregulates lung development and exacerbates eosinophilic inflammation, which are critical risk factors for asthma. However, it is unknown whether PFOS exerts sex-dependent effects on house dust mite (HDM) induced asthmatic progression and allergic inflammation. In this study, timed pregnant Balb/cJ dams were dosed orally via PFOS (1.0 mg/kg/d) spiked or vehicle control mealworms from gestational day (GD) 0.5 to postnatal day (PND) 21. Subsequently, HDM (30 μg/day) was administered starting at PND 77-82 for 10 days, and the mice were sacrificed 48 h after their final treatment. The serum and lung PFOS concentrations were 3.391 ± 0.189 μg/mL and 3.567 ± 0.1676 μg/g in the offspring, respectively. Male mice exposed to PFOS + HDM showed higher total cell counts in bronchoalveolar lavage fluid (BALF), macrophage counts, and eosinophil counts compared to mice exposed to HDM alone. Female mice exposed to PFOS + HDM had increased BALF eosinophil percentage, mucous production, alternatively activated (M2) macrophage polarization, and M2-associated gene expression compared to female mice exposed to HDM alone. PFOS exposure had no significant effect on HDM-induced IL-4, IL-5, or IL-13, but RANTES was further elevated in female mice. Overall, our data suggest that developmental PFOS exposure increased the risk of exacerbated eosinophilic inflammation and M2 polarization, which were more severe in female mice, suggesting sex-dependent developmental effects of PFOS on allergic airway responses.

Immunotoxicity of legacy and alternative per- and polyfluoroalkyl substances on zebrafish larvae

Hexafluoropropylene oxide dimer acid (HFPO-DA) and perfluoroethylcyclohexane sulfonate (PFECHS) are increasingly used as alternatives for perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). However, their immunotoxicity and underlying molecular mechanisms remain poorly understood. Here, to assess immunotoxic effects, zebrafish embryos were exposed to environmentally relevant concentrations of PFOA, PFOS, HFPO-DA, and PFECHS for four days. Results revealed that all four per- and polyfluoroalkyl substances (PFAS) resulted in decreased heart rate and spontaneous movement, and induced oxidative stress in zebrafish larvae. Notably, HFPO-DA exhibited more severe oxidative stress than PFOA. Immune dysfunction was observed, characterized by elevated cytokine, complement factor, nitric oxide, and neutrophil content, along with a significant decrease in lysozyme content. Transcriptomic analysis revealed the activation of Toll-like receptor (TLR)/NOD-like receptor (NLR)/RIG-I-like receptor (RLR) and associated downstream genes, indicating their pivotal role in PFAS-induced immunomodulation. Molecular docking simulations demonstrated stable interactions between PFAS and key receptors (TLR2, NOD2 and RIG-I). Overall, HFPO-DA and PFECHS exhibited immunotoxic effects in zebrafish larvae similar to legacy PFAS, providing important information for understanding the toxic mode of action of these emerging alternatives.

The phosphorylation of Smad3 by CaMKIIγ leads to the hepatocyte pyroptosis under perfluorooctane sulfonate exposure

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant and accumulated in the liver of mammals. PFOS exposure is closely associated with the development of pyroptosis. Nevertheless, the underlying mechanism is unclear. We found here that PFOS induced pyroptosis in the mice liver and L-02 cells as demonstrated by activation of the NOD-like receptor protein 3 inflammasome, gasdermin D cleavage and increased release of interleukin-1β and interleukin-18. The level of cytoplasmic calcium was accelerated in hepatocytes upon exposure to PFOS. The phosphorylated/activated form of calcium/calmodulin-dependent protein kinase II (CaMKII) was augmented by PFOS in vivo and in vitro. PFOS-induced pyroptosis was relieved by CaMKII inhibitor. Among various CaMKII subtypes, we identified that CaMKIIγ was activated specifically by PFOS. CaMKIIγ interacted with Smad family member 3 (Smad3) under PFOS exposure. PFOS increased the phosphorylation of Smad3, and CaMKII inhibitor or CaMKIIγ siRNA alleviated PFOS-caused phosphorylation of Smad3. Inhibiting Smad3 activity was found to alleviate PFOS-induced hepatocyte pyroptosis. This study puts forward that CaMKIIγ-Smad3 is the linkage between calcium homeostasis disturbance and pyroptosis, providing a mechanistic explanation for PFOS-induced pyroptosis.

In vitro cytotoxicity of six per- and polyfluoroalkyl substances (PFAS) in human immune cell lines

Per- and Polyfluoroalkyl substances (PFAS) are a group of persistent long-lived chemicals with global environmental contamination. The published literature is rife with confusing and sometimes contradictory effects of PFAS on animal and cell models, as well as epidemiological studies. Cytotoxicity studies are often used as an early indicator to guide safety requirements, regulation, and further studies and thus can be useful to understand important toxicity differences by various PFAS. Recent studies have found that PFAS are not equivalently toxic on all cell types, and that not all cell types exhibit the same sensitivity to individual PFAS. However, immune cells have not been well studied. As immune cells are important for regulating responses to environmental toxins, infection, and cancer, we sought to discover the sensitivity of these cells to various PFAS, including legacy and replacement compounds. We assessed a range of concentrations and found that immune cells are generally more robust when exposed to PFAS, and that Jurkat T-cells were more sensitive than THP-1 monocytes. As monocytes are critical for coordinating inflammatory responses to external threats with cell death cascades, we further investigated these cells. We discovered that THP-1 cells do not undergo organized or programmed death, such as apoptosis or pyroptosis, and instead PFAS exposure results in a more necrotic/lytic and unorganized death, likely contributing to potential inflammatory effects downstream.

Pyroptosis in health and disease: mechanisms, regulation and clinical perspective

Pyroptosis is a type of programmed cell death characterized by cell swelling and osmotic lysis, resulting in cytomembrane rupture and release of immunostimulatory components, which play a role in several pathological processes. Significant cellular responses to various stimuli involve the formation of inflammasomes, maturation of inflammatory caspases, and caspase-mediated cleavage of gasdermin. The function of pyroptosis in disease is complex but not a simple angelic or demonic role. While inflammatory diseases such as sepsis are associated with uncontrollable pyroptosis, the potent immune response induced by pyroptosis can be exploited as a therapeutic target for anti-tumor therapy. Thus, a comprehensive review of the role of pyroptosis in disease is crucial for further research and clinical translation from bench to bedside. In this review, we summarize the recent advancements in understanding the role of pyroptosis in disease, covering the related development history, molecular mechanisms including canonical, non-canonical, caspase 3/8, and granzyme-mediated pathways, and its regulatory function in health and multiple diseases. Moreover, this review also provides updates on promising therapeutic strategies by applying novel small molecule inhibitors and traditional medicines to regulate pyroptosis. The present dilemmas and future directions in the landscape of pyroptosis are also discussed from a clinical perspective, providing clues for scientists to develop novel drugs targeting pyroptosis.

Per- and Polyfluoroalkyl Substances (PFAS) Affect Female Reproductive Health: Epidemiological Evidence and Underlying Mechanisms

PFAS (per- and polyfluoroalkyl substances) have been extensively used across numerous industries and consumer goods. Due to their high persistence and mobility, they are ubiquitous in the environment. Exposure to PFAS occurs in people via multiple pathways such as dermal contact, water supply, air inhalation, and dietary intake. Even if some PFAS are being phased out because of their persistent presence in the environment and harmful impacts on human health, mixes of replacement and legacy PFAS will continue to pollute the ecosystem. Numerous toxicological investigations have revealed harmful effects of PFAS exposure on female reproductive health, e.g., polycystic ovaries syndrome, premature ovarian failure, endometriosis, reproductive system tumors, pregnancy complications, and adverse pregnancy outcomes. Despite extensive epidemiological studies on the reproductive toxicity of PFAS, research findings remain inconsistent, and the underlying mechanisms are not well understood. In this review, we give an in-depth description of the sources and pathways of PFAS, and then review the reproductive toxicity of PFAS and its possible mechanisms.

Disrupted mitochondrial transcription factor A expression promotes mitochondrial dysfunction and enhances ocular surface inflammation by activating the absent in melanoma 2 inflammasome

PURPOSE

Severe dry eye disease causes ocular surface damage, which is highly associated with mitochondrial dysfunction. Mitochondrial transcription factor A (TFAM) is essential for packaging mitochondrial DNA (mtDNA) and is crucial for maintaining mitochondrial function. Herein, we aimed to explore the effect of a decreased TFAM expression on ocular surface damage.

METHODS

Female C57BL/6 mice were induced ocular surface injury by topical administrating benzalkonium chloride (BAC). Immortalized human corneal epithelial cells (HCECs) were stimulated by tert-butyl hydroperoxide (t-BHP) to create oxidative stress damage. HCECs with TFAM knockdown were established. RNA sequencing was employed to analyze the whole-genome expression. Mitochondrial changes were measured by transmission electron microscopy, Seahorse metabolic flux analysis, mitochondrial membrane potential, and mtDNA copy number. TFAM expression and inflammatory cytokines were determined using RT-qPCR, immunohistochemistry, immunofluorescence, and immunoblotting.

RESULTS

In both the corneas of BAC-treated mice and t-BHP-induced HCECs, we observed impaired TFAM expression, accompanied by mitochondrial structure and function defects. TFAM downregulation in HCECs suppressed mitochondrial respiratory capacity, reduced mtDNA content, induced mtDNA leakage into the cytoplasm, and led to inflammation. RNA sequencing revealed the absent in melanoma 2 (AIM2) inflammasome was activated in the corneas of BAC-treated mice. The AIM2 inflammasome activation was confirmed in TFAM knockdown HCECs. TFAM knockdown in t-BHP-stimulated HCECs aggravated mitochondrial dysfunction and the AIM2 inflammasome activation, thereby further triggering the secretion of inflammatory factors such as interleukin (IL) -1β and IL-18.

CONCLUSIONS

TFAM reduction impaired mitochondrial function, activated AIM2 inflammasome and promoted ocular surface inflammation, revealing an underlying molecular mechanism for ocular surface disorders.

Per- and Polyfluoroalkyl Substances May Be Correlated With Chlamydia trachomatis: Data From the National Health and Nutrition Examination Survey 2003-2016

OBJECTIVE

Per- and polyfluoroalkyl substances (PFAS) alter immune function increasing infectious diseases risk. We examined the relationship between PFAS and chlamydia.

METHODS

A total of 3965 nonpregnant adults ages 18-39 years from the National Nutrition Examination Survey 2003-2016 cycles were included. Poisson regression with robust error variance estimated the prevalence ratio and 95% confidence intervals for the association between PFAS and chlamydia. A g computation model was used to examine PFAS mixtures and chlamydia.

RESULTS

In adjusted age and sex-stratified models, an increase in PFAS mixtures by one quintile was associated with chlamydia in older males and younger females. Associations were not observed before stratification.

CONCLUSIONS

PFAS exposure associated with higher chlamydia prevalence, but only in stratified models suggesting biological differences by gender and age. However, small sample sizes could have affected the precision of our models.

Caspase-8 promotes NLRP3 inflammasome activation mediates eye development defects in zebrafish larvae exposed to perfulorooctane sulfonate (PFOS)

Epidemiological evidence showed that serum high perfluorooctane sulfonate (PFOS) levels are associated with multiple eye related diseases, but the potential underlying molecular mechanisms remain poorly understood. Zebrafish and photoreceptor cell (661w) models were used to investigate the molecular mechanism of PFOS induced eye development defects. Our results showed a novel molecular mechanism of PFOS-induced inflammation response-mediated photoreceptor cell death associated with eye development defects. Inhibition of Caspase-8 activation significantly decreased photoreceptor cell death in PFOS exposure. Mechanistically, Toll-like receptor 4 (TLR4) mediates activation of Caspase-8 promote activation of NLR family pyrin domain-containing 3 (NLRP3) inflammasome to elicit maturation of interleukin-1 beta (IL-1β) via Caspase-1 activation, facilitating photoreceptor cell inflammation damage in PFOS exposure. In addition, we also made a novel finding that Caspase-3 activation was increased via Caspase-8 activation and directly intensified cell death. Our results show the important role of Caspase-8 activation in PFOS induced eye development defects and highlight Caspase-8 mediated activation of the NLRP3 inflammation triggers activation of Caspase-1 and promote the maturation of IL-1β in retinal inflammatory injury.

Cadmium activates the innate immune system through the AIM2 inflammasome

Cadmium (Cd) is a widely used heavy metal and has recently been recognized as a possible source of human toxicity due to its ability to accumulate in organs. Accumulation of heavy metals has several adverse effects, including inducing inflammation, in multiple organs, such as the testis. However, how Cd ions are sensed by host cells and how tissue inflammation eventually occurs remains unclear. Here, we show that Cd activates the AIM2 inflammasome by mediating genomic DNA release into the cytoplasm after DNA damage via oxidative stress, to trigger IL-1β secretion and pyroptosis. Specifically, the toxicity effects induced by Cd in cells were prevented by melatonin, which served as an antagonist of oxidative stress. Accordingly, in a mouse model, Cd-induced inflammation in the testis and consequential male reproductive dysfunction were effectively reversed by melatonin. Thus, our results suggest a function of AIM2 in Cd-mediated testis inflammation and identify AIM2 as a major pattern recognition receptor in response to heavy metal Cd ions.

Advances in immunology of male reproductive toxicity induced by common environmental pollutants

Humans are exposed to an ever-increasing number of environmental toxicants, some of which have gradually been identified as major risk factors for male reproductive health, even associated with male infertility. Male infertility is usually due to the reproductive system damage, which may be influenced by the exposure to contaminants such as heavy metals, plasticizers, along with genetics and lifestyle. Testicular immune microenvironment (TIM) is important in maintaining normal physiological functions of the testis, whether disturbed TIM after exposure to environmental toxicants could induce reproductive toxicity remains to be explored. Therefore, the current review aims to contribute to the further understanding of exposure and male infertility by characterizing environmental exposures and the effect on TIM. We first summarized the male reproductive toxicity phenotypes induced by common environmental pollutants. Contaminants including heavy metals and plastic additives and fine particulate matter (PM2.5), have been repetitively associated with male infertility, whereas emerging contaminants such as perfluoroalkyl substances and micro(nano)plastics have also been found to disrupt TIM and lead to male reproductive toxicity. We further reviewed the importance of TIM and its homeostasis in maintaining the normal physiological functions of the testis. Most importantly, we discussed the advances in immunology of male reproductive toxicity induced by metals and metalloids, plastic additives, persistent organic pollutants (POPs), micro(nano)plastic and PM2.5 to suggest the importance of reproductive immunotoxicology in the future study of environmental toxicants, but also contribute to the development of effective prevention and treatment strategies for mitigating adverse effects of environmental pollutants on human health.