Brain Accumulation and Toxicity Profiles of Silica Nanoparticles: The Influence of Size and Exposure Route

The crosstalk between autophagy and apoptosis mechanism of hemocytes in Chlamys farreri under B[a]P exposure in vitro

The impact of polycyclic aromatic hydrocarbons (PAHs) on the immune function of marine animals has garnered significant attention. C. farrei is frequently exposed to pollutants and has only innate immunity. To delve more deeply into the immunotoxicity mechanism of PAHs in C. farrei, its hemocytes were cultured in vitro as they were the primary drivers of immune activities. The autophagy and apoptosis of hemocytes are essential components of the immune response. The exposure of pollutant, autophagy and apoptosis of immune cells are often disrupted, leading to immunodeficiency. In aquatic animals, the mechanism of autophagy and apoptosis in hemocytes remains unclear, and the crosstalk between the two needs to be further investigated. To evaluate the mechanism of autophagy and apoptosis of hemocytes in vitro, 0 μM, 1 μM, 2.5 μM or 5 μM Benzopyrene (B[a]p) was chosen. Experimental results demonstrated that B[a]P triggered autophagosome formation, but also caused significant damage to lysosomes, resulting in a compromised autophagic flux. B[a]P causes an increase in apoptosis levels in hemocytes of C. farreri by affecting the transcriptional level of AIF. To further explore the crosstalk mechanism between the two, activator and inhibitor of autophagy were used. After adding autophagy activator or inhibitor, the present results indicated that Lysosomal function determined the patency of autophagic flux. When massive autophagosomes accumulate, it leads to a much higher rate of apoptosis through caspase-dependent apoptotic pathway. Lysosomal damage further leads to apoptosis and inhibit autophagy. In the B[a]P-treated group, immunological parameters were markedly decreased due to autophagy and apoptosis of hemocytes. The immunotoxicity mechanism of B[a]P in C. farreri hemocytes was investigated in present study, which enriched the immunotoxicity network.

Pulmonary microbiota disruption by respiratory exposure to carbon quantum dots induces neuronal damages in mice

Given the fact that carbon quantum dots (CQDs) have been commercially produced in quantities, it is inevitable to make their ways into environment and interact closely with the public. Even though CQDs in the environment have been reported to damage the central nervous system, the underlying mechanisms of neurotoxic effects of CQDs following respiratory exposure is still not clear. Intranasal instilled CQDs, mimicking respiratory exposure, induces neurobehavioral impairments associated with neuronal cell death of ferroptosis and disulfidptosis that is regulated by metabolic reprogramming of glutathione and cysteine pathways in the cortex and hippocampus where CQDs were hardly accumulated. Therefore, further exploration found that dysbiosis in the lung microbiome was found specifically manipulated by CQDs, which correlated with systemic and neuroinflammatory responses, implicating a lung-brain axis other than gut-brain axis as a critical pathway through which microbiota dysbiosis may impact neurological health after respiratory exposure to CQDs. This study pioneers the exploration of the neurological consequences of inhaled CQDs in the environment through the regulation of microbiome-lung-brain axis, which is key in understanding the mechanistic link between CQDs exposure and neurotoxicity. The findings could develop potential strategies for mitigating the neurological effects of CQDs even other types of nanoparticles.

Exploring the mechanisms of lithium neurotoxicity based on network toxicology and molecular docking

The rapid growth of lithium (Li)-related industrial activities and the application of Li-containing products have become an emerging human health concern. Li has been employed to treat human mental disorders; however, excessive Li salt accumulation can lead to brain damage. The mechanism of toxicity of long-term exposure to Li in the brain warrants further investigation. This research study established a network toxicology strategy to evaluate the molecular mechanisms and putative toxicity of lithium chloride (LiCl). The analysis of online databases identified 80 intersection targets for LiCl-induced neurotoxicity. Further refinements via STRING and Cytoscape software highlight 10 core targets. Furthermore, phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT), apoptosis pathways, and mitogen-activated protein kinase (MAPK) were enriched. Molecular docking validated the robust interaction of core targets with Li+. In vivo analyses of mice brains revealed substantial pathological alterations, neuronal degeneration, and nerve cell apoptosis. LiCl elevated the mRNA level of core genes. Further, the phosphorylation status of core proteins was primarily modulated by LiCl. Our investigation employs novel strategies for assessing the environmental pollutant toxicity and gives theoretical basis for elaborating the LiCl-induced neurotoxicity-related molecular mechanism. This may be employed to guide risk assessment of environmental Li exposure.

Warning on the inhalation of silica nanoparticles: Experimental evidence for its easy passage through the air-blood barrier, resulting in systemic distribution and pathological injuries

As a result of accumulating data, silica nanoparticles (SiNPs) are known to be harmful when inhaled. Nevertheless, the systemic research on its biological processes remains incompletely understood. In our work, we investigated the systemic effects in rats in response to the respiratory exposure of SiNPs, and in-depth clarified the particle distribution in vivo. Moreover, a model of the air-blood barrier was developed to assess the interplay of SiNPs with the epithelium/endothelium interface in vitro. The model was established via a transwell co-culturing of the alveolar epithelium (MLE-12) and the pulmonary microvascular epithelium (MPVECs). Consequently, our data revealed a systemic particle distribution and ensuing multi-tissue pathological injuries in SiNPs-instilled rats, including the heart, spleen, and kidneys. Simultaneously, the translocation of SiNPs passing through the air-blood barrier was verified in vitro. Also, a dose-dependent interruption to the air-blood barrier integrity by SiNPs was noticed in vitro, accompanied by the damage of tight junctions. SiNPs translocation across the air-blood barrier can inevitably facilitate the extra-pulmonary distribution of SiNPs and ensuing systemic effects. Overall, this study provides evidence on the systemic toxicity potential of SiNPs, while highlighting the significance of comprehending SiNPs toxicity and ultimately controlling the health hazards.

Intranasal Zinc Oxide Nanoparticles Induce Neuronal PANoptosis via Microglial Pathway

Recent data have revealed an increased risk of respiratory exposure during the manufacturing process and application of nanomaterials, resulting in an increased incidence of neurodegenerative diseases in the general population. Zinc oxide nanoparticles (ZNPs) are among the most used nanomaterials in biomedical and manufactured consumer products. In this study, neurological dysfunction after intranasal administration of ZNPs is observed, in which the ZNPs enter the brain via the nose-to-brain pathway and accumulate in microglia but not in astrocytes or neurons. By using a coculture system of microglia and neurons, the ZNPs are found that induce microglia-derived oxidative stress injury and lead to neuronal cell PANoptosis. In this context, ZNPs induced the generation of reactive oxygen species (ROS) originating from microglial NADPH oxidase 2 (NOX2), which further induced neuronal membrane lipid peroxidation and increased Ca2+ influx and mitochondrial DNA release. The leaked mitochondrial DNA subsequently initiates PANoptosis of neurons. Importantly, inhibition of microglial NOX2 activation can significantly alleviate brain oxidative injury and rescue neuronal PANoptosis. This study can advance the understanding of the mode of neuronal cell death while underscoring the importance of the interconnections among glial cells and neurons, which is beneficial for informing effective interventions for respiratory exposure to nanoparticles.

Uptake and transpiration of solid and hollow SiO2 nanoparticles by terrestrial plant (Apium Graveolens var. secalinum)

Recent studies have raised concerns about the potential toxicity of amorphous silica (SiO2) nanoparticles (NPs). This investigation explores the uptake, transport, and transpiration of silica NPs in Apium graveolens var. secalinum. The study reveals that SiO2 NPs can infiltrate the plant cell wall, translocate from roots to stems and leaves, leading to elevated silicon levels and posing ingestion exposure risks. Furthermore, the release of these NPs through transpiration droplets (481 ± 205 mg·m-2day-1 for 10 nm SiO2 NPs and 367 ± 22 mg·m-2day-1for 20 nm SiO2 NPs) presents significant health and environmental hazards. Modeling silica-coated NPs with thin-shelled hollow silica (h-SiO2) NPs demonstrate in vitro and in vivo toxicity. Exposure of mice to these NPs (10 mg·Kg-1day-1) over four weeks induces oxidative stress, inflammation, and apoptosis, along with observed tissue damage in the brain, liver, and kidneys. These findings necessitate additional research into the neurobehavioral impacts of nanoparticles on mice.

Review on the role of autophagy in the toxicity of nanoparticles and the signaling pathways involved

As the development of nanotechnology, the application of nanoproducts and the advancement of nanomedicine, the contact of nanoparticles (NPs) with human body is becoming increasingly prevalent. This escalation elevates the risk of NPs exposure for workers, consumers, researchers, and both aquatic and terrestrial organisms throughout the production, usage, and disposal stages. Consequently, evaluating nanotoxicity remains critically important, though standardized assessment criteria are still lacking. The diverse and complex properties of NPs further complicate the understanding of their toxicological mechanisms. Autophagy, a fundamental cellular process, exhibits dual functions-both pro-survival and pro-death. This review offers an updated perspective on the dual roles of autophagy in nanotoxicity and examines the factors influencing autophagic responses. However, no definitive framework exists for predicting NPs-induced autophagy. Beyond the conventional autophagy pathways, the review highlights specific transcription factors activated by NPs and explores metabolic reprogramming. Particular attention is given to NPs-induced selective autophagy, including mitophagy, ER-phagy, ferritinophagy, lysophagy, and lipophagy. Additionally, the review investigates autophagy's involvement in NPs-mediated biological processes such as ferroptosis, inflammation, macrophage polarization, epithelial-mesenchymal transition, tumor cell proliferation and drug resistance, as well as liver and kidney injury, neurotoxicity, and other diseases. In summary, this review presents a novel update on selective autophagy-mediated nanotoxicity and elucidates the broader interactions of autophagy in NPs-induced biological processes. Collectively, these insights offer valuable strategies for mitigating nanotoxicity through autophagy modulation and advancing the development of NPs in biomedical applications.

The Constituent-Dependent Translocation Mechanism for PM2.5 to Travel through the Olfactory Pathway

The neurotoxic risk of PM2.5 is of worldwide concern, but the pathways through which PM2.5 gets to the central nervous system are still under debate. The olfactory pathway provides a promising shortcut to the brain, which bypasses the blood-brain barrier for PM2.5. However, direct evidence is lacking, and the translocation mechanism is still unclear. This study used the primary murine olfactory sensory neurons (OSNs) as an in vitro model to explore the translocation mechanism of PM2.5 in the olfactory system. We found that PM2.5 can be internalized into the OSNs via vesicle transportation. This process responds only to the water-insoluble compositions of PM2.5 (WIS-PM2.5) and cannot be affected by the water-soluble compositions of PM2.5 (WS-PM2.5). PM2.5 can further disrupt the integrity of the barrier constituted by the OSNs, and WS-PM2.5 plays a heightened role in inducing the damages. Our results suggested that both cellular and paracellular pathways are possibly involved in the translocation of PM2.5 in the olfactory system. More advanced microscopy techniques need to be developed to explore the whole translocation process in the olfactory-brain pathway in both in vitro and in vivo models.

Mechanistic insights into zinc oxide nanoparticles induced embryotoxicity via H3K9me3 modulation

The widespread application of nanoparticles (NPs) in various fields has raised health concerns, especially in reproductive health. Our research has shown zinc oxide nanoparticles (ZnONPs) exhibit the most significant toxicity to pre-implantation embryos in mice compared to other common NPs. In patients undergoing assisted reproduction technology (ART), a significant negative correlation was observed between Zn concentration and clinical outcomes. Therefore, this study explores the impact of ZnONPs exposure on pre-implantation embryonic development and its underlying mechanisms. We revealed that both in vivo and in vitro exposure to ZnONPs impairs pre-implantation embryonic development. Moreover, ZnONPs were found to reduce the pluripotency of mouse embryonic stem cells (mESCs), as evidenced by teratoma and diploid chimera assays. Employing multi-omics approaches, including RNA-Seq, CUT&Tag, and ATAC-seq, the embryotoxicity mechanisms of ZnONPs were elucidated. The findings indicate that ZnONPs elevate H3K9me3 levels, leading to increased heterochromatin and consequent inhibition of gene expression related to development and pluripotency. Notably, Chaetocin, a H3K9me3 inhibitor, sucessfully reversed the embryotoxicity effects induced by ZnONPs. Additionally, the direct interaction between ZnONPs and H3K9me3 was verified through pull-down and immunoprecipitation assays. Collectively, these findings offer new insights into the epigenetic mechanisms of ZnONPs toxicity, enhancing our understanding of their impact on human reproductive health.

Evaluating the safety and efficiency of nanomaterials: A focus on mitochondrial health

Nanomaterials (NMs) have extensive application potential in drug delivery, tissue engineering, and various other domains, attributable to their exceptional physical and chemical properties. Nevertheless, an increasing body of literature underscores the diverse safety risks are associated with NMs upon interaction with the human body, including oxidative stress and programmed cell death. Mitochondria, serving as cellular energy factories, play a pivotal role in energy metabolism and the regulation of cell fate. Organs with substantial energy demands, including the heart and brain, are highly sensitive to mitochondrial integrity, with mitochondrial impairment potentially resulting in significant dysfunction and pathologies such as as heart failure and neurodegenerative disease. This review elucidates the pathways by which NMs translocate into mitochondria, their intracellular dynamics, and their impact on mitochondrial morphology, respiratory chain activity, and metabolic processes. We further investigate associated molecular mechanisms, including mitochondrial dynamic imbalance, calcium overload, and oxidative stress, and elucidate the pivotal roles of mitochondria in different forms of programmed cell death such as apoptosis and autophagy. Finally, we offer recommendations regarding the safety and efficacy of NMs for medical applications. By systematically analyzing the interactions and molecular mechanisms between NMs and mitochondria, this paper aims to enhance the toxicological evaluation framework of NMs and provide a foundational reference and theoretical basis for their clinical utilization.

Quercetin attenuates SiO2-induced ZBP-1-mediated PANoptosis in mouse neuronal cells via the ROS/TLR4/NF-κb pathway

With the increasing development of the society, silicon dioxide (SiO2) has been used in various fields, such as agriculture, food industry, etc., and its residues can pose a potential health threat to organisms. Quercetin (Que) is a potent free radical scavenger commonly found in plants. C57BL/6 mice were chosen to established a mouse model of SiO2 exposure and Que antagonism to investigate the mechanism of action of Que in rescuing the toxic damage of SiO2 on mouse cerebellum tissue. The results showed that cytoplasmic vacuolization, and inflammatory cell infiltration caused by SiO2 were alleviated by the addition of Que, and reduced oxidative stress in mouse cerebellum, alleviated the activation of TLR4 pathway induced by SiO2, and substantially reduced the occurrence of ZBP-1-mediated PANoptosis induced by SiO2 exposure in mouse cerebellum. In NS20Y cells, the oxidative stress activator (Elesclomol) and inhibitor N-acetyl cysteine (NAC), and the NF-κB activator 2 (NA2) were added. Elesclomol and NAC confirm the involvement of ROS in regulating the TLR4/NF-κB pathway, the TLR4/NF-κB pathway regulated ZBP-1-mediated PANoptosis in cerebellum and NS20Y cells induced by SiO2 exposure. In conclusion, the present experimental data suggest that Que mitigates the onset of ZBP-1-mediated PANoptosis in neuronal cells induced by SiO2 through the ROS/TLR4/NF-κB pathway. The present experimental findings help to understand the detoxification effect of Que in more tissues and provide an important reference for the rescue of organisms in long-term SiO2 environment.

Thyroid and parathyroid function disorders induced by short-term exposure of microplastics and nanoplastics: Exploration of toxic mechanisms and early warning biomarkers

Human exposure to micro- and nano-plastics (MNPs) primarily occurs through respiration and diet in the environment. However, the early effects and warning signs of MNPs exposure on vertebrates are unclear. Here we used intratracheal instillation and intragastric infusion to establish mouse models for MNPs exposure to systematically investigate the toxic mechanisms of MNPs on endocrine organs. Results showed that MNPs induced endocrine disruptions in short-term exposure by both dietary and respiratory pathways. Microplastics (MPs) exposed through dietary route were more toxic to thyroid gland, whereas nanoplastics (NPs) exhibited the highest level of toxicity to parathyroid gland through respiration. The transcriptome and validation of related functional genes revealed that MNPs affected the synthesis of thyroglobulin by interfering with the expressions of PAX8 and CREB. MNPs also impacted the levels of thyroid stimulating hormone, further mediating the secretion of thyroid hormones. Moreover, MNPs modulate the expression of Mafb, thereby exerting regulatory effects on parathyroid hormone (PTH) synthesis and growth development in parathyroid cells. Meanwhile, MNPs interfered with the expression of IP3R in the calcium signaling pathway, indirectly affecting the secretion of PTH. This study reveals the effects and mechanisms of MNPs on thyroid and parathyroid and highlights the significance of early warning of MNPs exposure.

Silicon dioxide nanoparticles induce anxiety-like behavior in a size-specific manner via the microbiota-gut-brain axis

The impacts of silicon dioxide nanoparticles (SiO2-NPs) on human health have attracted increasing interest due to their widespread utilization in medicine and food additives. However, the size-dependent effects of SiO2-NPs on brain health remain sparse. Herein we investigated alterations in behavioral patterns, the gut microbiota, inflammation and oxidative stress of mice after a 12-week exposure to SiO2-NPs with either small size (NP-S) or large size (NP-L). A more pronounced deleterious effect of NP-S was found on anxiety-like behavior in mice relative to NP-L. We also found that SiO2-NPs exposure induced inflammation and oxidative stress in the colon, hippocampus and cortex of mice in a size-specific manner. Correlation network analysis revealed potential links between anxiety-like behavior and SiO2-NPs-induced shifts in the gut microbiota including Parvibacter, Faecalibaculum, Gordonibacter and Ileibacterium. Furthermore, anxiety-like behavior caused by SiO2-NPs exposure exhibited correlations with decreased levels of hippocampal IL-10 and cortex Nqo1 as well as increased levels of intestinal Acox1 and hippocampal TNF-α. Therefore, our findings suggest that exposure to SiO2-NPs promoted anxiety-like behavior through the mediation of interplay between the gut and the brain, and SiO2-NPs of smaller size may generate a more adverse effect on brain health.

De novo design of a nanoregulator for the dynamic restoration of ovarian tissue in cryopreservation and transplantation

The cryopreservation and transplantation of ovarian tissue underscore its paramount importance in safeguarding reproductive capacity and ameliorating reproductive disorders. However, challenges persist in ovarian tissue cryopreservation and transplantation (OTC-T), including the risk of tissue damage and dysfunction. Consequently, there has been a compelling exploration into the realm of nanoregulators to refine and enhance these procedures. This review embarks on a meticulous examination of the intricate anatomical structure of the ovary and its microenvironment, thereby establishing a robust groundwork for the development of nanomodulators. It systematically categorizes nanoregulators and delves deeply into their functions and mechanisms, meticulously tailored for optimizing ovarian tissue cryopreservation and transplantation. Furthermore, the review imparts valuable insights into the practical applications and obstacles encountered in clinical settings associated with OTC-T. Moreover, the review advocates for the utilization of microbially derived nanomodulators as a potent therapeutic intervention in ovarian tissue cryopreservation. The progression of these approaches holds the promise of seamlessly integrating nanoregulators into OTC-T practices, thereby heralding a new era of expansive applications and auspicious prospects in this pivotal domain.

Emerging Perspectives on Prime Editor Delivery to the Brain

Prime editing shows potential as a precision genome editing technology, as well as the potential to advance the development of next-generation nanomedicine for addressing neurological disorders. However, turning in prime editors (PEs), which are macromolecular complexes composed of CRISPR/Cas9 nickase fused with a reverse transcriptase and a prime editing guide RNA (pegRNA), to the brain remains a considerable challenge due to physiological obstacles, including the blood-brain barrier (BBB). This review article offers an up-to-date overview and perspective on the latest technologies and strategies for the precision delivery of PEs to the brain and passage through blood barriers. Furthermore, it delves into the scientific significance and possible therapeutic applications of prime editing in conditions related to neurological diseases. It is targeted at clinicians and clinical researchers working on advancing precision nanomedicine for neuropathologies.

Beyond the promise: Exploring the complex interactions of nanoparticles within biological systems

The exploration of nanoparticle applications is filled with promise, but their impact on the environment and human health raises growing concerns. These tiny environmental particles can enter the human body through various routes, such as the respiratory system, digestive tract, skin absorption, intravenous injection, and implantation. Once inside, they can travel to distant organs via the bloodstream and lymphatic system. This journey often results in nanoparticles adhering to cell surfaces and being internalized. Upon entering cells, nanoparticles can provoke significant structural and functional changes. They can potentially disrupt critical cellular processes, including damaging cell membranes and cytoskeletons, impairing mitochondrial function, altering nuclear structures, and inhibiting ion channels. These disruptions can lead to widespread alterations by interfering with complex cellular signaling pathways, potentially causing cellular, organ, and systemic impairments. This article delves into the factors influencing how nanoparticles behave in biological systems. These factors include the nanoparticles' size, shape, charge, and chemical composition, as well as the characteristics of the cells and their surrounding environment. It also provides an overview of the impact of nanoparticles on cells, organs, and physiological systems and discusses possible mechanisms behind these adverse effects. Understanding the toxic effects of nanoparticles on physiological systems is crucial for developing safer, more effective nanoparticle-based technologies.

Exposure to different surface-modified polystyrene nanoparticles caused anxiety, depression, and social deficit in mice via damaging mitochondria in neurons

Nanoplastics (NPs) are unavoidable hazardous materials that result from the human production and use of plastics. While there is evidence that NPs can bioaccumulate in the brain, no enough research regarding the pathways by which NPs reach the brain was conducted, and it is also urgently needed to evaluate the health threat to the nervous system. Here, we observed accumulation of polystyrene nanoplastics (PS-NPs) with different surface modifications (PS, PS-COOH, and PS-NH2) in mouse brains. Further studies showed that PS-NPs disrupted the tight junctions between endothelial cells and transport into endothelial cells via the endocytosis and macropinocytosis pathways. Additionally, NPs exposure induced a series of alternations in behavioral tests, including anxiety- and depression-like changes and impaired social interaction performance. Further results identified that NPs could be internalized into neurons and localized in the mitochondria, bringing about mitochondrial dysfunction and a concurrent decline of ATP production, which might be associated with abnormal animal behaviors. The findings provide novel insights into the neurotoxicity of NPs and provide a basis for the formulation of policy on plastic production and usage by relevant government agencies.

Mixed Metal Components in PM2.5 Contribute to Chemokine Receptor CCR5-Mediated Neuroinflammation and Neuropathological Changes in the Mouse Olfactory Bulb

Particulate matter, especially PM2.5, can invade the central nervous system (CNS) via the olfactory pathway to induce neurotoxicity. The olfactory bulb (OB) is the key component integrating immunoprotection and olfaction processing and is necessarily involved in the relevant CNS health outcomes. Here we show that a microglial chemokine receptor, CCR5, is the target of environmentally relevant PM2.5 in the OB to trigger neuroinflammation and then neuropathological injuries. Mechanistically, PM2.5-induced CCR5 upregulation results in the pro-inflammatory paradigm of microglial activation, which subsequently activates TLR4-NF-κB neuroinflammation signaling and induces neuropathological changes that are closely related to neurodegenerative disorders (e.g., Aβ deposition and disruption of the blood-brain barrier). We specifically highlight that manganese and lead in PM2.5 are the main contributors to CCR5-mediated microglial activation and neuroinflammation in synergy with aluminum. Our results uncover a possible pathway of PM2.5-induced neuroinflammation and identify the principal neurotoxic components, which can provide new insight into efficiently diminishing the adverse health effects of PM2.5.

Coronal ApoE Protein Combines with LRP1 to Inactivate GSK3β That Mitigates Silica Nanoparticle-Induced Brain Lesion

Silica nanoparticles (SiO2 NPs) are widely used engineered materials that warrant their obvious environmental exposure risk. Our previous study has shown that different routes of SiO2 NP exposure on the glycogen synthase kinase 3 beta (GSK3β) activity were related to the serum proteins enriched on the surface of SiO2 NPs, which implied that a particular protein in the serum changed the inherent toxic behavior of SiO2 NPs and inhibited the activation of GSK3β by SiO2 NPs. Here, we identified that the SiO2 NP surface enriched a large amount of apolipoprotein E (ApoE), and the ApoE protein corona bound to the lipoprotein receptor-related protein 1 (LRP1) to inactivate GSK3β, thereby reducing the damage of SiO2 NPs to the brain. This work presented the first evidence that specific biocorona reduced the toxicity of SiO2 NPs at the molecular level, which helped to elucidate the role of specific corona components on nanotoxicity.

Silica Nanoparticle Exposure Implicates β-Amyloid (1-42) Inbound and the Accelerating Alzheimer's Disease Progression in Mice Overexpressing Mutated Forms of Human Amyloid Precursor Protein and Presenilin 1 Genes

The increasing nanoparticle (NP) applications in the biomedical field have become an emerging concern regarding human health. NP exposure may play a role in the accelerating Alzheimer's disease (AD) progression; however, the etiology of this disorder is complex and remains largely unclear. Here, we identified that intravenous injection of silica NPs (SiNPs) caused the blood-brain barrier breakdown via downregulating tight junction-related gene expressions. Meanwhile, SiNPs upregulate the transport receptor for advanced glycation end products (RAGE) that govern the β-amyloid (Aβ) influx to the brain; however, low-density lipoprotein receptor-related protein 1 (LRP1) that controls the efflux of Aβ from the brain was not affected. Consequently, an increase in Aβ burden in the brain of SiNP-challenged APP/PS1 mice was found. Intriguingly, plasma apolipoprotein E (ApoE) adsorbed on the surface of SiNPs partially relieves this effect. Using ApoE knockout (ApoE-/-) mice, we confirmed that SiNPs covered with serum without ApoE showed further elevated AD symptoms. Together, this study offered a compilation of data to support the potential risk factors of NP exposure and AD pathology.

Implications of ferroptosis in silver nanoparticle-induced cytotoxicity of macrophages

Metal nanoparticles (NPs) are widely used in daily life and commercial activities owing to their unique physicochemical properties. Consequently, there is an increasing risk of daily and occupational exposure to metal NPs, which raises concerns regarding their health hazards. Programmed cell deaths (PCDs) have been clarified to be involved in metal NP-induced cytotoxicity, including apoptosis, autophagy, and pyroptosis. However, whether and how ferroptosis, a newly recognized PCD, contributes to metal NP-induced cell death remain unclear. In this study, we investigated the ferroptotic effects of two representative metal NPs, silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs), on macrophages in vitro. Our results revealed that AgNPs, rather than AuNPs, induced non-apoptotic PCD, accompanied by lipid peroxidation and iron homeostasis disorders, which are two hallmarks of ferroptosis, in macrophages. Treatment with a ferroptosis inhibitor (ferrostatin-1) and iron chelator (deferoxamine) reversed AgNP-induced PCD, corroborating the induction of ferroptosis upon exposure to AgNPs. Moreover, our results revealed that smaller AgNPs elicited greater ferroptotic effects on macrophages than larger ones. Importantly, ferroptosis in AgNP-treated macrophages was mainly triggered by AgNPs per se rather than by Ag ions. Overall, our study highlights the ferroptotic effects elicited by AgNPs in macrophages, which will promote the understanding of their cytotoxic effects and facilitate the safer design of metal nanoproducts.

Ambient air pollution and infant health: a narrative review

The extensive evidence regarding the effects of ambient air pollution on child health is well documented, but limited review summarized their health effects during infancy. Symptoms or health conditions attributed to ambient air pollution in infancy could result in the progression of severe diseases during childhood. Here, we reviewed previous empirical epidemiological studies and/or reviews for evaluating the linkages between ambient air pollution and various infant outcomes including adverse birth outcomes, infant morbidity and mortality, early respiratory health, early allergic symptoms, early neurodevelopment, early infant growth and other relevant outcomes. Patterns of the associations varied by different pollutants (i.e., particles and gaseous pollutants), exposure periods (i.e., pregnancy and postpartum) and exposure lengths (i.e., long-term and short-term). Protection of infant health requires that paediatricians, researchers, and policy makers understand to what extent infants are affected by ambient air pollution, and a call for action is still necessary to reduce ambient air pollution.

Co-Exposure of Ambient Particulate Matter and Airborne Transmission Pathogens: The Impairment of the Upper Respiratory Systems

Recent evidence has pinpointed the positive relevance between air particulate matter (PM) pollution and epidemic spread. However, there are still significant knowledge gaps in understanding the transmission and infection of pathogens loaded on PMs, for example, the interactions between pathogens and pre-existing atmospheric PM and the health effects of co-exposure on the inhalation systems. Here, we unraveled the interactions between fine particulate matter (FPM) and Pseudomonas aeruginosa (P. aeruginosa) and evaluated the infection and detrimental effects of co-exposure on the upper respiratory systems in both in vitro and in vivo models. We uncovered the higher accessibility and invasive ability of pathogens to epithelial cells after loading on FPMs, compared with the single exposure. Furthermore, we designed a novel laboratory exposure model to simulate a real co-exposure scenario. Intriguingly, the co-exposure induced more serious functional damage and longer inflammatory reactions to the upper respiratory tract, including the nasal cavity and trachea. Collectively, our results provide a new point of view on the transmission and infection of pathogens loaded on FPMs and uncover the in vivo systematic impairments of the inhalation tract under co-exposure through a novel laboratory exposure model. Hence, this study sheds light on further investigations of the detrimental effects of air pollution and epidemic spread.