Background Surging production of lithium-ion batteries elevates exposure to NCM cathodes, triggering complex internal metal co-exposure. However, current data are limited to individual metals, the health impacts of this co-exposure remain unclear, directly hindering biomarkers development for risk assessment. Methods Employing a “data-driven to experimentally-validated” strategy, we utilized network toxicology of components to elucidate the health risks and pathogenic characteristics of co-exposure. These were substantiated using an in vivo mouse model and a 402-subject occupational cohort. Guided by these features, we integrated whole-blood transcriptomics with machine learning to identify a plasma protein panel. A predictive risk model was constructed by integrating the measured population protein panel levels with risk stratification. Findings NCM metals share common risks on cardiovascular disease, especially heart injury, with related biomarkers elevated 2.05-fold in highly exposed populations. Furthermore, this risk is characterized by a pathogenic axis featuring IL1B (upregulated 1.70-fold) as a central hub gene activating the NF-κB pathway (2.98-fold) and increase of IL1Bhi macrophages (3.6-fold). Leveraging these characteristics, a five-plasma protein biomarker panel (IL1B, FOS, DUSP1, HSPA5, and RGS2) was identified to develop a machine learning-driven risk model, which showed consistent performance with established heart injury biomarkers (r = 0.80, p < 0.01). Interpretation Our findings define a previously underappreciated IL1B-centric heart injury risk associated with NCM exposure, providing a scalable biomarker panel and risk model for risk assessment.

Organophosphate flame retardants (OPFRs) have been widely used as the main alternatives to bromine-based flame retardants, resulting in their widespread detection in environmental media and even in human blood. The potential health risks arising therefrom, particularly the direct impacts on the blood system, have become a focus in the field of environmental health. This article systematically reviewed the latest research progress on the hematotoxicity of OPFRs, covering three core aspects: the toxic effects aspect, which systematically elaborated on the bidirectional interference of OPFRs with coagulation function, their toxic effects on the hematopoietic system, and their disruptive effects on blood biochemical metabolism; the mechanistic analysis aspect, which dissected the multi-pathway, multi-target toxic mechanism network of OPFRs, including common pathways based on oxidative stress and inflammatory responses, the direct and indirect regulation of coagulation function mediated by nuclear receptors and endocrine disruption, and the disturbance of blood cell production at the source through disruption of the hematopoietic microenvironment; and the risk assessment aspect, which, in response to the limitations of traditional methods, focused on the application prospects and core advantages of novel approaches based on structure-activity relationships in filling data gaps and achieving precise risk prediction. This review aims to systematically summarize the research progress on the mechanisms of OPFR-induced hematotoxicity, providing systematic theoretical support for subsequent in-depth mechanistic studies, targeted epidemiological investigations, and the optimization of risk assessment models.

Environmental nanoparticle exposure in real-world scenarios is often intermittent rather than continuous, yet its associated risks and mechanisms remain poorly understood. This study investigates whether such intermittent exposure induces maladaptive trained immunity within the bone marrow (BM) to drive inflammatory injury. We establish a physiologically relevant "prime-rest-rechallenge" mouse model of intermittent inhalation to cobalt (II, III) oxide (Co3O4) nanoparticles, a representative environmental stressor. Using this model, we provide in vivo evidence that intermittent Co3O4 exposure establishes a lasting, maladaptive immune memory in the BM─termed BM-mediated trained immunity. Primary Co3O4 exposure induces hematopoietic reprogramming toward a myeloid-biased phenotype, a state that is restored following a rest period. Upon secondary challenge, this reprogrammed state drives an augmented myelopoietic response, characterized by a 1.5-fold expansion of myeloid progenitors and a sustained output of mature myeloid cells. Integrated bioinformatics analysis and functional validation identify tumor necrosis factor-alpha (TNF-α), the highest-degree node (degree = 17) in the interaction network, as the central mediator orchestrating this BM-mediated trained immunity. In vivo TNF-α neutralization abrogates this trained myelopoietic phenotype. Furthermore, this Co3O4-induced, TNF-α-dependent trained immunity exacerbates inflammatory injury in distant organs, including the heart and brain. Our work establishes intermittent exposure as a critical yet overlooked risk paradigm, reveals trained immunity as a mechanistic link between nanoparticles and inflammatory disorders, and positions TNF-α as a potential therapeutic target to mitigate pollution-related risks.

The global transition to electric vehicles hinges on lithium-ion batteries, yet the health risks of their core components, such as nickel-manganese-cobalt (NCM) cathodes, remain a critical and misunderstood gap, threatening a truly sustainable energy transition. Herein, we reveal that inhaled NCM particles undergo sustained lysosomal dissolution, transforming into metal mixtures whose composition mirrors the parent material. Crucially, we decipher the unique toxicological interactions within this biologically generated mixture-antagonism from Ni/Co and synergy from Mn. This fundamental discovery of NCM's biological fate unlocks accurate risk assessment. Building on this mechanistic insight, we identified the Integrated Addition and Interaction (IAI) model as the framework capable of capturing complex interactions. Applying this model to real-world exposure data uncovers moderate yet significant population-level health risks. Our work establishes a transformative, evidence-based paradigm that connects in-body material transformation to real-world health outcomes, providing the scientific foundation to ensure that the clean energy transition is not only green but fundamentally safe for human well-being.

Volatile organic compounds (VOCs) are prevalent indoor pollutants, posing significant health risks. However, current toxicological data focus predominantly on individual compounds, leaving a critical gap in understanding how exposure to mixed VOCs alters the plasma proteome and impacts health risk prediction. Herein, we investigated VOCs-induced hematological disturbances using a whole-body inhalation exposure model with C57BL/6J mice (n = 3) exposed to decoration-derived VOCs for 8 weeks. By integrating plasma proteomics with machine learning, we demonstrated that VOCs exposure significantly disrupts hemostatic homeostasis, primarily by perturbing the complement and coagulation cascades. Network enrichment and correlation analyses further identified a network of suppressed pathways (e.g., platelet activation and focal adhesion) and activated pathways (e.g., necroptosis and IL-17 signaling pathway) that collectively drive this dysregulation. Critically, we identified downregulated von Willebrand factor (VWF) and cell division control protein 42 (CDC42) as a robust biomarker signature, as evidenced by correlation coefficients (r) of 0.91 and 0.90 with complement and coagulation cascades, respectively. Leveraging these biomarkers, we developed a highly accurate health risk scoring model. This study provides the first comprehensive molecular portrait of VOCs-induced hematological disturbances and presents a novel proteomics-driven framework for the early prediction and intervention of VOCs-related health effects.

Organophosphate flame retardants (OPFRs), as emerging substitutes for halogenated flame retardants, are widely detected in populations and pose global health concerns. However, their structural diversity and expanding numbers challenge conventional experimental risk assessment. Here, we present a quantitative mode-of-action (qMOA) framework integrating structural attributes and cascade mechanistic insights to enable predictive risk evaluation. From 68 registered OPFRs, 59 representative structurally diverse compounds (average pairwise similarity value: 0.51) were selected for model training. The model identified benzene ring count (55.34%) and substituent type (39.14%) as the primary structural determinants of toxicity. This structure-activity relationship was experimentally validated across tiered events in mitochondrial dysfunction─a recognized MOA for environmental pollutants. Leveraging the validated link and experimental data, we developed a qMOA model to calculate mitochondrial dysfunction MOA-specific threshold doses for individual OPFRs. For example, model-derived thresholds for widely detected OPFRs were 27.84 μg/mL for EHDPP (two benzene rings) and 75.76 μg/mL for TEP (three CH3 substituents, nonbenzene ring). This enables direct comparison with human exposure data, revealing that relatively multibenzene-ring OPFRs pose higher potential health risks. This study advances a mechanism-informed strategy that enhances the reliability of toxicity inference and enables rapid risk quantification for diverse existing OPFRs and emerging analogues.

Background The widespread environmental contamination by cobalt compounds, coupled with their documented respiratory toxicities, has become a pressing public health concern. Current mechanistic research on the health impacts of these substances lacks coherence and integration, highlighting the need for a comprehensive investigation into the mechanisms of cobalt-induced lung injury. Methods Utilizing CTDbase and NetInfer databases, we obtained target genes of cobalt and its compound and ascertained their associated lung adverse outcomes. Disease-related targets were retrieved from OMIM, DisGeNet, GeneCards, and NCBI databases. A protein-protein interaction (PPI) network was constructed to identify the core targets between compounds and diseases. Based on the DAVID database, enrichment pathways were evaluated by GO and KEGG analyses. Finally, single-cell analysis was conducted to investigate specific cell types implicated in the cobalt-induced lung hazards. Results Pulmonary hypertension (PH) was determined as the most critical lung injury associated with cobalt compounds. In total, we identified 275 compound-related and 3146 PH-related targets, ultimately pinpointing 169 overlapping targets. Among these, 28 pivotal co-targets were implicated in cobalt and its compound-induced PH, including IL6, AKT1, TNF, TP53, NFKB1, HIF1A, etc., which were primarily involved in the IL-17, TNF, and HIF-1 signaling pathways. Moreover, monocytes and macrophages were recognized as effector cells underlying the induction of PH by cobalt exposure, with CXCL8 and HIF1A serving as signature genes. Conclusion Our study not only elucidates pivotal target genes, pathways, and specific cell types involved in cobalt-induced lung hazards, but also establishes a novel approach to clarify the mechanisms underlying metal toxicity.

Organophosphate esters (OPEs) have emerged as a significant environmental concern due to their widespread occurrence and potential human health risks. The presence of OPEs in human blood suggests direct interactions with hematological components, which may compromise hemostatic balance and lead to adverse health outcomes. Despite the critical role of hemostatic balance in maintaining blood stability, the effects of OPEs on this system remain poorly understood. This investigation was undertaken to delineate the effects and potential mechanisms of OPEs that modulate hemostasis, utilizing in silico approach and high-throughput in vitro investigation. We analyzed 85 environmentally prevalent OPEs for their structural descriptors and affinity for proteins essential to hemostatic function. The multiple linear regression implicated aryl-OPEs, distinguished by their benzene ring scaffold, as potent disruptors of hemostatic balance. This analysis result was rigorously validated through the in vitro hemostatic balance assays. Further investigation through network toxicology, artificial intelligence (α-Fold) algorithms, and an agonist cotreatment assay revealed proliferator-activated receptor γ (PPARγ) as a key mediator of aryl-OPEs induced hemostatic disruption. By integrating in vitro experimental insights with in vivo exposure data, we concluded that specific aryl-OPEs, such as bisphenol a bis (diphenyl phosphate) (BDP) and cresyl diphenyl phosphate (CDP), pose a moderate risk to the hemostatic balance of the general population. Our findings not only contribute to the prioritization of OPEs risk management but also establish a methodology for assessing the hematological toxicity of emerging pollutants.

Ischemic heart disease (IHD) is a major cardiovascular health concern. In addition to metabolic and behavioral risks, diesel particulate matter (DPM), with a widely exposed population, is an important external environmental risk factor for IHD. However, the effect biomarkers used to diagnose DPM-caused IHD and underlying mechanisms remain unknown. We investigated the biomarkers and underlying mechanisms of DPM in relation to myocardial hypoxia injury. This study applied a unique population of diesel engine testers with stable DPM exposure. Electrocardiogram examination, echocardiogram examination, serum levels of myocardial enzymes, and 6-min walking test were used for the myocardial risks assessment. A mouse model exposed to occupational environmental DPM dose and in vitro models of DPM-induced myocardial hypoxia injury were used for assessment of mitochondrial aerobic metabolism via the oxygraph-2k system, western blotting, and kits. Ion fluorescence probes, ion supplements, and mitochondrial RNA splicing protein 2 (Mrs2) overexpression transfection were used in further investigations and verifications of the mechanism of mitochondrial Mg2+ deficiency. We identified compromised myocardial mitochondrial aerobic metabolism as a precursor biomarker for the cardiac risk of myocardial hypertrophy and hypoxia injury in DPM exposure. DPM induce mitochondrial Mg2+ deficiency of cardiomyocytes, which in turn disrupt the mitochondrial aerobic metabolism processes, including the tricarboxylic acid cycle, oxidative phosphorylation, and ATP synthesis. Mg2+ deficiency is mediated by the disruption of Mg2+ transport proteins, such as DPM-enhanced hyperubiquitination and degradation of Mrs2, a protein responsible for mitochondrial Mg2+ uptake. Our findings show that compromised mitochondrial aerobic metabolism, associated with Mg2+ deficiency, serves as a critical biomarker for DPM-induced IHD and represents a promising investigative avenue for intervention.

Tris(2-chloroethyl) phosphate (TCEP), a prevalent organophosphorus flame retardant, has been identified in various environmental matrices and human blood samples, provoking alarm regarding its hematological toxicity, a subject that has not been thoroughly investigated. Red blood cells (RBCs), or erythrocytes, are the predominant cell type in peripheral blood and are crucial for the maintenance of physiological health. This investigation employed oral gavage to examine the effects of TCEP exposure on erythrocyte counts in mice and to clarify the underlying mechanisms. The results demonstrated a marked increase in circulating RBC counts post-TCEP exposure, concomitantly heightening the risk of polycythemia vera (PV). TCEP exposure stimulated erythropoiesis across all stages of medullary development, including the differentiation of hematopoietic stem cells into erythroid progenitors, the progression of erythrocyte development, and the maturation of erythrocyte. Moreover, TCEP potentiated extramedullary erythropoiesis in the spleen and liver. Subsequent bioinformatics analysis implied that TCEP-induced erythropoiesis was attributed to p53 downregulation. Thus, these findings indicate that TCEP disrupts erythrocyte-mediated hematological homeostasis through the enhancement of both medullary and extramedullary erythropoiesis, leading to the alteration of hematological equilibrium.

Environmental pollutants like PM2.5 threaten hematopoietic homeostasis, yet how real-world exposure disrupts blood cell production, especially locally in the lung and systemically in the bone marrow (BM), remains poorly understood. Previous studies often used artificial particles or lacked mechanistic insights into systemic effects. Hypoxia-inducible factor-1alpha (HIF-1α) is essential for hematopoietic stem cell (HSC) maintenance. Herein, we utilized a real-ambient PM2.5 exposure system and conducted a detailed characterization of hematopoietic and downstream immune cell populations in mice with myeloid lineage-specific knockout of HIF-1α (mHIF-1α−/−) and their wild-type littermate controls. Our findings demonstrate that real-ambient PM2.5 exposure induces a HIF-1α-dependent myeloid-biased hematopoiesis within both the lung and BM. This bias results in an accumulation of mature myeloid cells, particularly neutrophils and macrophages, in peripheral organs such as the liver and spleen. Critically, this cellular redistribution precipitates inflammatory injury in a HIF-1α-dependent manner. These results provide novel insights into how environmental contaminants, exemplified by PM2.5, perturb hematopoiesis, highlighting the critical role of HIF-1α in mediating lineage-specific hematopoietic responses and subsequent inflammatory sequelae.

Perfluorochemicals (PFCs) are emergent and persistent organic pollutants with widespread application. Their structural similarity and detection in serum raises substantial concerns regarding their toxicological effects. While the endocrine-disrupting effects of PFCs are well-recognized, the structure-activity relationship with respect to vascular function has not been investigated yet. This study addresses this critical gap by investigating the impact of PFCs on endothelial cell function, a key determinant of cardiovascular health. Through a machine learning-based quantitative structure-activity relationship (QSAR) model, we analyzed 16 structural descriptors for 23 environmentally prevalent PFCs with respect to their binding affinities to endothelial cell receptors. The eXtreme Gradient Boosting (XGBoost) algorithm suggested short-chain PFCs with strong acid groups may as particularly detrimental to endothelial cells, a finding substantiated by subsequent cell culture experiments. We also integrated computational and experimental approaches, providing a detailed understanding of the structure-activity and dose-response relationships of PFCs. Furthermore, the population health risk assessment, linking in vitro adverse effect with in vivo exposure data, indicated differences in risks across countries due to the global shift in the fluoride industry; the entire Chinese population is at high risk, with risk varying by gender and industrialization level. This study not only elucidates the structure-activity relationship of PFCs on vascular function but also offers a strategic framework for managing toxic PFCs and proposing the development of safer alternatives.

Tris(2-chloroethyl) phosphate, an extensively used organophosphorus flame retardant in consumer products, has caused pervasive environmental contamination and increased human exposure, raising concerns about its cardiotoxic potential. However, the detailed toxicological profile, particularly concerning the crucial cardiac energy metabolism, and the precise mechanisms remain poorly understood. This study in C57BL/6 J mice exposed to TCEP for 36 days at varying doses revealed cardiac dysfunction, structural abnormalities, and hypoxia. Analysis of energy metabolism indicated a shift from aerobic processes (tricarboxylic acid cycle, β-oxidation, and oxidative phosphorylation) to anaerobic metabolism (glycolysis). Further restoration of energy metabolism remodeling, which was achieved by activating oxidative phosphorylation and inhibiting glycolysis, mitigated TCEP-induced cardiotoxicity, highlighting the critical role of energy metabolism remodeling in TCEP-induced cardiac injury. Mechanistically, this metabolic remodeling was primarily driven by TCEP-enhanced hyperubiquitination and degradation of prolyl hydroxylase domain 2 (PHD2), leading to the accumulation and nuclear translocation of hypoxia-inducible factor-1α (HIF-1α). This study yields key insights into the cardiotoxicity of TCEP-like OPFRs exposure, and emphasizes the role of altered cardiac energy metabolism and the oxygen-sensing pathway, thereby proposing potential intervention strategies for OPFR-induced cardiac toxicity.

Perfluorinated compounds (PFCs) are a well-recognized environmental risk factor for atherosclerosis. However, corresponding atherogenic risk in susceptible populations consuming high-fat diets (HFDs) remains unclear. Here, we found that perfluorooctane sulfonic acid (PFOS), a canonical PFCs, elevated the atherogenic risk in mice fed with HFD, which was characterized by an increased number of pro-inflammatory phenotype macrophages. We also found that macrophages exhibited a metabolic reprogramming to glycolysis, which was attributed to increased intracellular Fe2+ level. Mechanistic investigation revealed that PFOS directly bound to the iron-storage site on the ferritin heavy chain, subsequently weakening the iron-storage function. Notably, PFCs with acidic substituents and short chains had a higher atherogenic risk, as evidenced in the crucial indicators and observed in a population with a high triglyceride level. These findings highlight the potential atherogenic risk posed by PFCs exposure in susceptible populations consuming HFD and provide a potential intervention target.

Volatile organic compounds (VOCs) emitted from interior decorations are suggested to pose substantial respiratory hazards as they disturb the immune response in the lung. Despite this, the characteristics and mechanisms underlying immune cell responses to real-world VOC mixtures, rather than previously individual or dominant VOC species, remain poorly understood. Employing a whole-body inhalation exposure model, we reveal that interior decorative VOCs alter pulmonary immune cell profiles with a persistent increase in alveolar T cells. This sustained elevation results from intensified lymphoid-biased hematopoiesis in the bone marrow (BM) rather than in situ lung, which is followed by thymic maturation and subsequent recruitment to lung tissues. The ex vivo biosensor and antibody neutralization assays clarify that VOCs-induced lymphoid-biased hematopoiesis is primarily driven by osteogenic differentiation within the BM niche, a process further regulated by interleukin-6 (IL-6) and interleukin-17A (IL-17A). Moreover, the cohort study associates VOCs-expanded lymphocytes with increased risks of obstructive lung diseases, where exposed individuals show elevated IL-6 and IL-17A levels, correlating with VOC concentrations and lymphocyte proportions. These findings highlight compelling indicators (i.e., T cells) and potential interventions (i.e., IL-6 and IL-17A) for evaluating and mitigating VOC-associated respiratory risks.

Tris (2-chloroethyl) phosphate (TCEP), recognized as an emerging pollutant, has been frequently detected in human blood. Maintenance of blood homeostasis is indispensable for regulating various physiological states and overall health, yet hematological toxicology of TCEP has not been extensively investigated. Platelets, a vital component of blood, are fundamental in the processes of hemostasis and thrombosis through their activation; thus, this study was designed to elucidate the effects and underlying mechanisms of TCEP on platelet activation. Utilizing an in vivo model, we conducted a proteomic analysis of platelets and found that TCEP exposure inhibited platelet activation. An ex vivo platelet evaluation system was employed to further dissect the processes of platelet activation, revealing that TCEP predominantly suppressed platelet aggregation, degranulation and clot retraction. These processes were highly dependent on energy metabolism, and TCEP was found to decrease ATP levels, primarily by impairing glycolysis and pentose phosphate pathways. Subsequent investigation into the molecular mechanisms revealed that TCEP decreased the activity of phosphofructokinase platelet (PFKP) by enhancing O-linked N-acetylglucosamine (O-GlcNAc) transferase interaction with PFKP. This study is the first to uncover the disruptive effects of TCEP on platelet activation process, providing valuable insights into the assessment of hematologic health risks associated with TCEP-like emerging pollutants exposure.

Tetrabromobisphenol A (TBBPA) and its derivatives widely exist in various environments and biota. Although the available data indicate that TBBPA exposure is highly associated with the increased incidence of endometrial cancer (EC), the effects of TBBPA and its main derivatives on EC proliferation and the involved crucial mechanism remain unclear. The present study aimed to investigate the effects of TBBPA and its derivatives under environmental concentrations on the proliferation of EC, and the crucial mechanism on the progression of EC caused by bromine flame retardants exposure. In this research, TBBPA and two of the most common TBBPA derivatives including TBBPA bis (2-hydroxyethyl ether) (TBBPA-BHEE) and TBBPA bis (dibromopropyl ether) (TBBPA-BDBPE) were screened for their capacities in induced EC proliferation and explored the related mechanism by in vitro cell culture model and in vivo mice model. Under environmental concentrations, TBBPA promoted the proliferation of EC, the main derivatives of TBBPA (TBBPA-BHEE and TBBPA-BDBPE) did not present the similar facilitation effects. The ubiquitination degradation of p53 was crucial in TBBPA induced EC proliferation, which resulted in the increase of downstream cell cycle and decrease of apoptosis. The further molecular docking result suggested the high affinity between TBBPA and ubiquitinated proteasome. This finding revealed the effects of TBBPA and its derivatives on EC proliferation, thus providing novel insights into the underlying mechanisms of TBBPA-caused EC.

The global practice of reusing sewage sludge in agriculture and its landfill disposal reintroduces environmental contaminants, posing risks to human and ecological health. This study screened sewage sludge from 30 Chinese cities for androgen receptor (AR) disruptors, utilizing a disruptor list from the Toxicology in the 21st Century program (Tox21), and identified 25 agonists and 33 antagonists across diverse use categories. Predominantly, natural products 5α-dihydrotestosterone and thymidine emerged as agonists, whereas the industrial intermediate caprolactam was the principal antagonist. In-house bioassays for identified disruptors displayed good alignment with Tox21 potency data, validating employing Tox21 toxicity data for theoretical toxicity estimations. Potency calculations revealed 5α-dihydrotestosterone and two pharmaceuticals (17β-trenbolone and testosterone isocaproate) as the most potent AR agonists and three dyes (rhodamine 6G, Victoria blue BO, and gentian violet) as antagonists. Theoretical effect contribution evaluations prioritized 5α-dihydrotestosterone and testosterone isocaproate as high-risk AR agonists and caprolactam, rhodamine 6G, and 8-hydroxyquinoline (as a biocide and a preservative) as key antagonists. Notably, 16 agonists and 20 antagonists were newly reported in the sludge, many exhibiting significant detection frequencies, concentrations, and/or toxicities, demanding future scrutiny. Our study presents an efficient strategy for estimating environmental sample toxicity and identifying key toxicants, thereby supporting the development of appropriate sludge management strategies.

Per- and polyfluoroalkyl substances (PFAS), widely utilized in consumer products, have been linked to an increased risk of cardiovascular disease (CVD). With the increasing prevalence of high-fat diet, a common risk factor for CVD, the PFAS exposed populations who consume a high-fat diet will inevitably grow and may have a higher CVD risk. However, the potential toxic effect and mode of action remain elusive. We constructed a mouse model orally exposed to perfluorooctane sulfonate (PFOS), a prototypical PFAS, and fed a high-fat diet. PFOS exposure induced cardiomyopathy and structural abnormalities in the mice heart. Moreover, a characteristic of energy metabolism remodeling from aerobic to anaerobic process was observed. Interestingly, PFOS was rarely detected in heart but showed high level in serum, suggesting an indirect route of action for PFOS-caused cardiac toxicity. We further demonstrated that PFOS-caused circulating inflammation promoted metabolic remodeling and contractile dysfunction in cardiomyocytes. Wherein, PFOS stimulated the release of IL-1β from circulating proinflammatory macrophages mediated by NF-κB and caspase-1. This study provides valuable data on PFAS-induced cardiac risks associated with exposed populations with increasing high-fat diet consumption, highlighting the significance of indirect pathways in PFOS's impact on the heart, based on the distribution of internal exposure.

Nanomaterials have been extensively applied in multiple industries, among which silver nanoparticles (AgNPs), silicon dioxide nanoparticles (SiNPs), and gold nanoparticles (AuNPs) have become representative of widely consumed NPs. Limited knowledge is available regarding the subcellular responses of NPs with different physicochemical properties, i.e. material type and size, under the noncytotoxic concentrations. Macrophages are important sensitive cells exposed to NPs, and mitochondria are sensitive organelles that respond at the subcellular level. Herein, we found that sublethal concentrations of AgNPs and SiNPs, not AuNPs, decreased the mitochondrial membrane potential (MMP) and tubular mitochondria, and further resulted in an increase of ROS level and a decrease of ATP generation. AgNPs and SiNPs can also disturb mitochondrial dynamics manifested as increasing Mfn2 expression and decreasing Drp1 expression. Further assessments for mitochondrial function showed that AgNPs and SiNPs exposure led to a decrease in the gene expressions related to complex I (Ndufa8 and Ndufs2), complex III (Uqcrc2 and Uqcrfs1), complex IV (Cox6b1), and activity of complex I, suggesting their potential roles in impairing cellular respiration. In terms of the effects of NPs with different sizes, stronger toxicity was observed in smaller-sized nanoparticles. Among the above mitochondrial changes, we identified that ROS, ATP, MMP, tubular mitochondria, and expression of Drp1 were relatively sensitive indicators in subcellular response to NPs. With the above sensitive indicators, the comparison of heterogeneity between material type and size of the NPs showed that material type occupied a main influence on subcellular mitochondrial effects. Our finding provided important data on the potential subcellular risks of NPs, and indicated the vital role of material type for a better understanding of the nanomaterial biological safety.