Anionic nanoplastic exposure induces endothelial leakiness

Wet oxidation technology can significantly reduce both microplastics and nanoplastics

For the resource recovery of biomass waste, it is a challenge to simultaneously remove micro-/nano-plastics pollution but preserve organic resources. Wet oxidation is a promising technology for valorization of organic wastes through thermal hydrolysis and oxidation. This might in turn result in the degradation of microplastics in the presence of oxygen and high temperatures. Based on this hypothesis, this study quantified both microplastics and nanoplastics in an industrial-scale wet oxidation reactor from a full-size coverage perspective. Wet oxidation significantly reduced the size and mass of individual microplastics, and decreased total mass concentration of microplastics and nanoplastics by 94.8 % to 98.6 %. This technology also reduced the micro- and nanoplastic shapes and polymer types, resulting in a complete removal of fibers, clusters, polypropylene (PP) and poly(methyl methacrylate) (PMMA). The present study confirms that wet oxidation technology is effective in removing microplastics and nanoplastics while recovering organic waste.

Polystyrene nanoplastics accelerate atherosclerosis: Unraveling the impact on smooth muscle cells through KIF15-mediated migration

Microplastics and nanoplastics (MNPs) originating from plastic pollution pose potential threats to cardiovascular health, with prior studies linking MNPs to atherosclerosis. Our earlier research elucidated how nanoplastics enhance macrophages' phagocytic activity, leading to the formation of foam cells and an elevated risk of atherosclerosis. However, the specific influence of MNPs on smooth muscle cells (SMCs) in the context of MNP-induced atherosclerosis remains poorly understood. In this study, ApoE knockout (ApoE-/-) male mice with a high-fat diet were orally exposed to environmentally realistic concentrations of 2.5-250 mg/kg polystyrene nanoplastics (PS-NPs, 50 nm) for consecutive 19 weeks. Cardiovascular toxicity was comprehensively assessed through histopathological, transcriptomic, and proteomic analyses, while mechanisms underlying this toxicity were explored through in vitro studies. Herein, hematoxylin and eosin staining revealed accelerated atherosclerotic plaque development in ApoE-/- mice exposed to PS-NPs. Multi-omics analysis identified kinesin family member 15 (KIF15) as a pivotal target molecule. Both in vitro and in vivo experiments affirmed the specific upregulation of KIF15 in mouse aortic SMCs exposed to PS-NPs. Furthermore, in vitro experiments demonstrated that PS-NPs can promote the migration ability of MOVAS cells. Knockdown of Kif15 revealed its role in reducing MOVAS cell migration, with subsequent exposure to PS-NPs reversing the increased migration ability. This suggests that PS-NPs promote SMC migration by upregulating KIF15, and the migration of SMCs is closely associated with atherosclerosis outcomes. This study significantly advances our understanding of MNP-induced cardiovascular toxicity, providing valuable insights for risk assessment of human MNP exposure.

The porcine corpus luteum as a model for studying the effects of nanoplastics

Nanoplastics (NPs) affect fertility. We evaluated the effects of NPs treatment on luteal and endothelial cells. We examined crucial markers of growth and redox status. NPs treatment did not induce changes in ATP levels in luteal cells, while it increased (p< 0.05) their proliferation. In endothelial cells, no change in proliferation was detected, while an increase (p<0.05) in ATP levels was observed. The increase of reactive oxygen species, superoxide anion (p<0.05) and nitric oxide (p<0.001) was detected in both cell types, which also showed changes in superoxide dismutase enzyme activity as well as an increase of non-enzymatic antioxidant power (p<0.05). A decrease (p<0.05) in progesterone production as well as an increase of vascular endothelial growth factor A levels were detected (p<0.05). In addition, a dose-dependent accumulation of NPs in endothelial cells was shown, that likely occurred through adhesion and internalization. Results underline potential risk of NPs for corpus luteum functionality.

Spiky tubular nanoparticles with low protein corona can realize efficient and non-destructive penetration through endothelial barrier

Upon intravascular applications, i.e., cancer treatment, nanoparticles (NPs) are required to deliver through blood circulation, sustain serum protein interactions, before they penetrate the blood vessels and reach targeted sites for payload drug release. For a delivery process as such, it is elusive and difficult to comprehend the morphological change of NP surface and evaluate associated effects on its targeted delivery. Herein, we used silica NPs with different surface modifications to demonstrate the morphological impact of NPs during the application of the NP-blood protein interaction, vascular endothelial cell penetration, subsequent targeted delivery and photodynamic therapy efficacy, and pursue high drug-load NPs with surface designs. Compared to solid and mesoporous NPs, we found the spiky tubular NPs reserved the NPs' antifouling properties (or shedding of "protein corona"), promoted better endothelial penetration and less destruction in vitro and in vivo. Such effects could be attributed to their spiky surface structures, which can limit the NP-protein interaction area and promote the NP-protein steric hindrance. Further in molecular simulations, we determined that the spiky tubular morphological modification on NPs enhanced the interaction free energy and lowered the amino acids number and the subsequent frequency in contacting with VE-cadherin of vascular endothelia. As a result, the spiky tubular NPs demonstrated its advantages in mitigating damages to VE-cadherin stability and endothelial cell integrity. Exploiting such spiky tubular surface modification, we can improve the NP delivery efficiency and prohibit the leakiness of vascular endothelia, helping address challenges faced by tumor migration in nanomedicine applications for cancer therapy.

A Self-Cascade Penetrating Brain Tumor Immunotherapy Mediated by Near-Infrared II Cell Membrane-Disrupting Nanoflakes via Detained Dendritic Cells

Immunotherapy can potentially suppress the highly aggressive glioblastoma (GBM) by promoting T lymphocyte infiltration. Nevertheless, the immune privilege phenomenon, coupled with the generally low immunogenicity of vaccines, frequently hampers the presence of lymphocytes within brain tumors, particularly in brain tumors. In this study, the membrane-disrupted polymer-wrapped CuS nanoflakes that can penetrate delivery to deep brain tumors via releasing the cell-cell interactions, facilitating the near-infrared II (NIR II) photothermal therapy, and detaining dendritic cells for a self-cascading immunotherapy are developed. By convection-enhanced delivery, membrane-disrupted amphiphilic polymer micelles (poly(methoxypoly(ethylene glycol)-benzoic imine-octadecane, mPEG-b-C18) with CuS nanoflakes enhances tumor permeability and resides in deep brain tumors. Under low-power NIR II irradiation (0.8 W/cm2), the intense heat generated by well-distributed CuS nanoflakes actuates the thermolytic efficacy, facilitating cell apoptosis and the subsequent antigen release. Then, the positively charged polymer after hydrolysis of the benzoic-imine bond serves as an antigen depot, detaining autologous tumor-associated antigens and presenting them to dendritic cells, ensuring sustained immune stimulation. This self-cascading penetrative immunotherapy amplifies the immune response to postoperative brain tumors but also enhances survival outcomes through effective brain immunotherapy.

Hazard assessment of nanoplastics is driven by their surface-functionalization. Effects in human-derived primary endothelial cells

During plastic waste degradation into micro/nanoplastics (MNPLs) their physicochemical characteristics including surface properties (charge, functionalization, biocorona, etc.) can change, potentially affecting their biological effects. This paper focuses on the surface functionalization of MNPLs to determine if it has a direct impact on the toxicokinetic and toxicodynamic interactions in human umbilical vein endothelial cells (HUVECs), at different exposure times. Pristine polystyrene nanoplastics (PS-NPLs), as well as their carboxylated (PS-C-NPLs) and aminated (PS-A-NPLs) forms, all around 50 nm, were used in a wide battery of toxicological assays. These assays encompassed evaluations on cell viability, cell internalization, induction of intracellular reactive oxygen species (iROS), and genotoxicity. The experiments were conducted at a concentration of 100 μg/mL, chosen to ensure a high internalization rate across all treatments while maintaining a sub-toxic concentration. Our results show that all PS-NPLs are internalized by HUVECs, but the internalization dynamic depends on the particle's functionalization. PS-NPLs and PS-C-NPLs internalization modify the morphology of the cell increasing its inner complexity/granularity. Regarding cell toxicity, only PS-A-NPLs reduced cell viability. Intracellular ROS was induced by the three different PS-NPLs but at different time points. Genotoxic damage was induced by the three PS-NPLs at short exposures (2 h), but not for PS-C-NPLs at 24 h. Overall, this study suggests that the toxicological effects of PSNPLs on HUVEC cells are surface-dependent, highlighting the relevance of using human-derived primary cells as a target.

Nanoplastic Size and Surface Chemistry Dictate Decoration by Human Saliva Proteins

Environmental pollution with plastic polymers has become a global problem, leaving no continent and habitat unaffected. Plastic waste is broken down into smaller parts by environmental factors, which generate micro- and nanoplastic particles (MNPPs), ultimately ending up in the human food chain. Before entering the human body, MNPPs make their first contact with saliva in the human mouth. However, it is unknown what proteins attach to plastic particles and whether such protein corona formation is affected by the particle's biophysical properties. To this end, we employed polystyrene MNPPs of two different sizes and three different charges and incubated them individually with saliva donated by healthy human volunteers. Particle zeta potential and size analyses were performed using dynamic light scattering complemented by nanoliquid chromatography high-resolution mass spectrometry (nLC/HRMS) to qualitatively and quantitatively reveal the protein soft and hard corona for each particle type. Notably, protein profiles and relative quantities were dictated by plastic particle size and charge, which in turn affected their hydrodynamic size, polydispersity, and zeta potential. Strikingly, we provide evidence of the latter to be dynamic processes depending on exposure times. Smaller particles seemed to be more reactive with the surrounding proteins, and cultures of the particles with five different cell lines (HeLa, HEK293, A549, HepG2, and HaCaT) indicated protein corona effects on cellular metabolic activity and genotoxicity. In summary, our data suggest nanoplastic size and surface chemistry dictate the decoration by human saliva proteins, with important implications for MNPP uptake in humans.

Controlling nanoparticle-induced endothelial leakiness with the protein corona

Understanding nanoparticle-cell interaction is essential for advancing research in nanomedicine and nanotoxicology. Apart from the transcytotic pathway mediated by cellular recognition and energetics, nanoparticles (including nanomedicines) may harness the paracellular route for their transport by inducing endothelial leakiness at cadherin junctions. This phenomenon, termed as NanoEL, is correlated with the physicochemical properties of the nanoparticles in close association with cellular signalling, membrane mechanics, as well as cytoskeletal remodelling. However, nanoparticles in biological systems are transformed by the ubiquitous protein corona and yet the potential effect of the protein corona on NanoEL remains unclear. Using confocal fluorescence microscopy, biolayer interferometry, transwell, toxicity, and molecular inhibition assays, complemented by molecular docking, here we reveal the minimal to significant effects of the anionic human serum albumin and fibrinogen, the charge neutral immunoglobulin G as well as the cationic lysozyme on negating gold nanoparticle-induced endothelial leakiness in vitro and in vivo. This study suggests that nanoparticle-cadherin interaction and hence the extent of NanoEL may be partially controlled by pre-exposing the nanoparticles to plasma proteins of specific charge and topology to facilitate their biomedical applications.

Quantitative and rapid detection of nanoplastics labeled by luminescent metal phenolic networks using surface-enhanced Raman scattering

The escalating prevalence of nanoplastics contamination in environmental ecosystems has emerged as a significant health hazard. Conventional analytical methods are suboptimal, hindered by their inefficiency in analyzing nanoplastics at low concentrations and their time-intensive processes. In this context, we have developed an innovative approach that employs luminescent metal-phenolic networks (L-MPNs) coupled with surface-enhanced Raman spectroscopy (SERS) to separate and label nanoplastics, enabling rapid, sensitive and quantitative detection. Our strategy utilizes L-MPNs composed of zirconium ions, tannic acid, and rhodamine B to uniformly label nanoplastics across a spectrum of sizes (50-500 nm) and types (e.g., polystyrene, polymethyl methacrylate, polylactic acid). Rhodamine B (RhB) functions as a Raman reporter within these L-MPNs-based SERS tags, providing the requisite sensitivity for trace measurement of nanoplastics. Moreover, the labeling with L-MPNs aids in the efficient separation of nanoplastics from liquid media. Utilizing a portable Raman instrument, our methodology offers cost-effective, swift, and field-deployable detection capabilities, with excellent sensitivity in nanoplastic analysis and a detection threshold as low as 0.1 μg/mL. Overall, this study proposes a highly promising strategy for the robust and sensitive analysis of a broad spectrum of particle analytes, underscored by the effective labeling performance of L-MPNs when coupled with SERS techniques.

The biodistribution of polystyrene nanoparticles administered intravenously in the chicken embryo

Nanoplastics can cause severe malformations in chicken embryos. To improve our understanding of the toxicity of nanoplastics to embryos, we have studied their biodistribution in living chicken embryos. We injected the embryos in the vitelline vein at stages 18-19. We injected polystyrene nanoparticles (PS-NPs) tagged with europium- or fluorescence. Their biodistribution was tracked using inductively-coupled plasma mass spectrometry on tissue lysates, paraffin histology, and vibratome sections analysed by machine learning algorithms. PS-NPs were found at high levels in the heart, liver and kidneys. Furthermore, PS-NPs crossed the endocardium of the heart at sites of epithelial-mesenchymal transformation; they also crossed the liver endothelium. Finally, we detected PS-NPs in the allantoic fluid, consistent with their being excreted by the kidneys. Our study shows the power of the chicken embryo model for analysing the biodistribution of nanoplastics in embryos. Such experiments are difficult or impossible in mammalian embryos. These findings are a major advance in our understanding of the biodistribution and tissue-specific accumulation of PS-NPs in developing animals.

Combined exposure of nano-titanium dioxide and polystyrene nanoplastics exacerbate oxidative stress-induced liver injury in mice by regulating the Keap-1/Nrf2/ARE pathway

It is well known that polystyrene nanoplastics (PS-NaP) and nano-titanium dioxide (TiO2 NPs) are frequently co-appeared in daily life and can cause liver injury when they accumulate in the liver. Nonetheless, the combined toxicological impacts and potential molecular mechanisms of PS-NaP and TiO2 NPs in the hepatic system have not been revealed. Thus, we conducted experiments on C57BL/6 mice exposed to PS-NaP or/and TiO2 NPs for 4 weeks. The findings suggested that PS-NaP and TiO2 NPs co-exposed significantly altered the hepatic function parameters, levels of antioxidant-related enzymes and genes expression of Keap-1/Nrf2/ARE signaling pathway, as well as significantly increased the hepatic Ti contents, aggravated hepatic pathological and oxidative stress (OS) damage compared with individual exposure to PS-NaP or TiO2 NPs. Using N-Acetyl-L-cysteine (NAC), an OS inhibitor, we further demonstrated that OS played a pivotal role in coexposure-induced liver injury. NAC reduced the levels of OS in mice, which mitigated co-exposure-induced liver injury. Taken together, we proposed that PS-NaP and TiO2 NPs co-exposed activated the Keap-1, then inhibited the recognition of Nrf2 and ARE, consequently exacerbated liver injury. These findings shed light on the co-toxicity and potential mechanism of nanoplastics and nanoparticles, which informed the risk assessment of human exposure to environmental pollutants.

Nematode Uptake Preference toward Different Nanoplastics through Avoidance Behavior Regulation

Expounding bioaccumulation pathways of nanoplastics in organisms is a prerequisite for assessing their ecological risks in the context of global plastic pollution. Invertebrate uptake preference toward nanoplastics is a key initial step of nanoplastic food chain transport that controls their global biosafety, while the biological regulatory mechanism remains unclear. Here, we reveal a preferential uptake mechanism involving active avoidance of nanoplastics by Caenorhabditis elegans and demonstrate the relationship between the uptake preference and nanoplastic characteristics. Nanoplastics with 100 nm in size or positive surface charges induce stronger avoidance due to higher toxicity, causing lower accumulation in nematodes, compared to the 500 nm-sized or negatively charged nanoplastics, respectively. Further evidence showed that nematodes did not actively ingest any types of nanoplastics, while different nanoplastics induced defense responses in a toxicity-dependent manner and distinctly stimulated the avoidance behavior of nematodes (ranged from 15.8 to 68.7%). Transcriptomics and validations using mutants confirmed that the insulin/IGF signaling (IIS) pathway is essential for the selective avoidance of nanoplastics. Specifically, the activation of DAF-16 promoted the IIS pathway-mediated defense against nanoplastics and stimulated the avoidance behavior, increasing the survival chances of nematodes. Considering the genetical universality of this defense response among invertebrates, such an uptake preference toward certain nanoplastics could lead to cascaded risks in the ecosystem.

Nanoplastic Stimulates the Amyloidogenesis of Parkinson's Alpha-Synuclein NACore

Environmental plastic wastes are potential health hazards due to their prevalence as well as their versatility in initiating physical, chemical, and biological interactions and transformations. Indeed, recent research has implicated the adverse effects of micro- and nano-plastics, including their neurotoxicity, yet how plastic particulates may impact the aggregation pathway and toxicity of amyloid proteins pertinent to the pathologies of neurological diseases remains unknown. Here, electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS) is employed to reveal the polymorphic oligomerization of NACore, a surrogate of alpha-synuclein that is associated with the pathogenesis of Parkinson's disease. These data indicate that the production rate and population of the NACore oligomers are modulated by their exposure to a polystyrene nanoplastic, and these cellular assays further reveal an elevated NACore toxicity in microglial cells elicited by the nanoplastic. These simulations confirm that the nanoplastic-NACore association is promoted by their hydrophobic interactions. These findings are corroborated by an impairment in zebrafish hatching, survival, and development in vivo upon their embryonic exposure to the nanoplastic. Together, this study has uncovered the dynamics and mechanism of amyloidogenesis elevated by a nanoplastic trigger, shedding a new light on the neurological burden of plastic pollution.

Exosome Heterogeneity Affects the Distal "Barrier-Crossing" Trafficking of Exosome Encapsulated Quantum Dots

The biological activities of nanoparticles (NPs), which include endocytosis by macrophages and subsequent intracellular degradation and/or release, transfer to other cells, or translocation across tissue barriers, highly depend on their fate in living organisms. Yet, translocation across barriers, especially the distal "barrier-crossing" trafficking of NPs, is still unclear. The exosome (Exo) plays a crucial role in intercellular communication and biological barrier trafficking. Here, we report that ZnCdSe@ZnS quantum dots (QDs), as a representation of NPs in biomedical applications, could cross the blood-brain barrier and approach the mouse brain via active Exo encapsulation. By employing multiple techniques, we demonstrated that QDs were internalized by macrophages (J774A.1) and tumor cells (HeLa) and then released to the extracellular environment along with Exo. Exo encapsulation facilitates the distal barrier-crossing trafficking of QDs in vivo, while Exo biogenesis inhibitor GW4869 suppressed the QDs enriched in the brains of mice with a 4T1-Luc breast cancer xenograft. Interestingly, Exo heterogeneity affects the distal trafficking of enveloped QDs. Exo derived from tumorous HeLa cells, not macrophages, that were enriched in functional proteins with cell adhesion, cell migration, axon guidance, and cell motility, showed a better capacity for the remote trafficking of QDs. This study proposes Exo as a vehicle to deliver exogenous NPs to translocate across the distal barrier and provides further information for biomedical application and the risk assessment of NPs.

Nanoplastic propels diet-induced NAFL to NASH via ER-mitochondrial tether-controlled redox switch

Nonalcoholic steatohepatitis (NASH) is multifactorial that lifestyle, genetic, and environmental factors contribute to its onset and progression, thereby posing a challenge for therapeutic intervention. Nanoplastic (NP) is emerged as a novel environmental metabolism disruptor but the etiopathogenesis remains largely unknown. In this study, C57BL/6 J mice were fed with normal chow diet (NCD) and high-fat diet (HFD) containing 70 nm polystyrene microspheres (NP). We found that dietary-derived NP adsorbed proteins and agglomerated during the in vivo transportation, enabling diet-induced hepatic steatosis to NASH. Mechanistically, NP promoted liver steatosis by upregulating Fatp2. Furthermore, NP stabilized the Ip3r1, and facilitated ER-mitochondria contacts (MAMs) assembly in the hepatocytes, resulting in mitochondrial Ca2+ overload and redox imbalance. The redox-sensitive Nrf2 was decreased in the liver of NP-exposed mice, which positively regulated miR26a via direct binding to its promoter region [-970 bp to -847 bp and -318 bp to -176 bp]. NP decreased miR26a simultaneously upregulated 10 genes involved in MAMs formation, lipid uptake, inflammation, and fibrosis. Moreover, miR26a inhibition elevated MAMs-tether Vdac1, which promoted the nucleus translocation of NF-κB P65 and Keap1 and functionally inactivated Nrf2, leading to a vicious cycle. Hepatocyte-specific overexpressing miR26a effectively restored ER-mitochondria miscommunication and ameliorated NASH phenotype in NP-exposed and Keap1-overexpressed mice on HFD. The hepatic MAM-tethers/Nrf2/miR26a feedback loop is an essential metabolic switch from simple steatosis to NASH and a promising therapeutic target for oxidative stress-associated liver damage and NASH.

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.

An Emerging Role of Micro- and Nanoplastics in Vascular Diseases

Vascular diseases are the leading causes of death worldwide, and they are attributable to multiple pathologies, such as atherosclerosis, diabetes, and chronic obstructive pulmonary disease. Exposure to various environmental contaminants is associated with the development of various diseases, including vascular diseases. Among environmental contaminants, micro- and nanoplastics have gained attention as global environmental risk factors that threaten human health. Recently, extensive research has been conducted on the effects of micro- and nanoplastics on various human diseases, including vascular diseases. In this review, we highlight the effects of micro- and nanoplastics on vascular diseases.

Nano-induced endothelial leakiness-reversing nanoparticles for targeting, penetration and restoration of endothelial cell barrier

Nano-induced endothelial leakiness (NanoEL) can improve the ability of nanoparticles (NPs) to enter the tumor environment, nevertheless, it can inadvertently trigger adverse effects such as tumor metastasis. To overcome these concerns, it becomes important to develop a NPs design strategy that capitalizes on the NanoEL effect while averting unwanted side effects during the drug delivery process. Herein, we introduce the PLGA-ICG-PEI-Ang1@M NP which has a core comprising poly (lactic-co-glycolic acid) (PLGA) and the inner shell with a highly positively charged polyethyleneimine (PEI) and the anti-permeability growth factor Angiopoietin 1 (Ang1), while the outer shell is camouflaged with a Jurkat cell membrane. During the drug delivery process, our NPs exhibit their capability to selectively target and penetrate endothelial cell layers. Once the NPs penetrate the endothelial layer, the proton sponge effect triggered by PEI in the acidic environment surrounding the tumor site can rupture the cell membrane on the NPs' surface. This rupture, in turn, enables the positively charged Ang1 to be released due to the electrostatic repulsion from PEI and the disrupted endothelial layer can be restored. Consequently, the designed NPs can penetrate endothelial layers, promote the cell layer recovery, restrict the tumor metastasis, and facilitate efficient cancer therapy. STATEMENT OF SIGNIFICANCE.

Endothelial leakiness elicited by amyloid protein aggregation

Alzheimer's disease (AD) is a major cause of dementia debilitating the global ageing population. Current understanding of the AD pathophysiology implicates the aggregation of amyloid beta (Aβ) as causative to neurodegeneration, with tauopathies, apolipoprotein E and neuroinflammation considered as other major culprits. Curiously, vascular endothelial barrier dysfunction is strongly associated with Aβ deposition and 80-90% AD subjects also experience cerebral amyloid angiopathy. Here we show amyloid protein-induced endothelial leakiness (APEL) in human microvascular endothelial monolayers as well as in mouse cerebral vasculature. Using signaling pathway assays and discrete molecular dynamics, we revealed that the angiopathy first arose from a disruption to vascular endothelial (VE)-cadherin junctions exposed to the nanoparticulates of Aβ oligomers and seeds, preceding the earlier implicated proinflammatory and pro-oxidative stressors to endothelial leakiness. These findings were analogous to nanomaterials-induced endothelial leakiness (NanoEL), a major phenomenon in nanomedicine depicting the paracellular transport of anionic inorganic nanoparticles in the vasculature. As APEL also occurred in vitro with the oligomers and seeds of alpha synuclein, this study proposes a paradigm for elucidating the vascular permeation, systemic spread, and cross-seeding of amyloid proteins that underlie the pathogeneses of AD and Parkinson's disease.

Nanoplastics induce neuroexcitatory symptoms in zebrafish (Danio rerio) larvae through a manner contrary to Parkinsonian's way in proteomics

Although nanoplastics (NPs) can penetrate the blood-brain barrier and accumulate in the brain, the neurotoxicity of these particles and the mechanisms associated with their unique physio-chemical properties have yet to be sufficiently ascertained. In this study, we assessed the neuroexcitatory symptoms of zebrafish (Danio rerio) larvae treated with polystyrene (PS) NPs based on an examination of locomotory behaviour, dopamine levels, and acetylcholinesterase activity. We found that PS NPs caused oxidative stress and inhibited atoh1a expression in the cerebellum of Tg(atoh1a:dTomato) transgenic zebrafish larvae, thereby indicating damage to the central nervous system. In contrast to the Parkinson's disease (PD) like effects induced by most types of nanoparticles, such as graphene oxide, we established that PS NPs influenced the neuronal proteomic profiles of zebrafish larvae in a manner contrary to the molecular pathways characteristic of PD-like effects, which could be explained by the molecular dynamic simulation. Unlike graphene oxide nanoparticles that promote significant change in the internal structure of neuroproteins, the complex macromolecular polymers of PS NPs promoted the coalescence and increased expression of neuroproteins, thereby plausibly contributing to the neuroexcitatory symptoms observed in treated zebrafish larvae. Consequently, compared with traditional nanoparticles, we believe that the unique physio-chemical properties of NPs could be a potential factor contributing to their toxicity.

Environmental relevant concentrations of polystyrene nanoplastics and lead co-exposure triggered cellular cytotoxicity responses and underlying mechanisms in Eisenia fetida

Heavy metal pollution of soils and the widespread use of plastics have caused environmental problems worldwide. Nanoplastics (NPs) contaminants in water and soil environments can adsorb heavy metals, thereby affecting the bioavailability and toxicity of heavy metals. In this paper, the effect of co-exposure of polystyrene microspheres with 100 nm particle size and lead acetate (Pb) on the Eisenia fetida coelomocytes was investigated. The environmental concentration of NPs used was 0.01 mg/L and the concentration of Pb ranged from 0.01 to 1 mg/L, and the exposed cells were incubated at 298 k for 24 h. Our study demonstrated that exposure of cells to environmental relevant concentrations of NPs did not significantly affect the cytotoxicity of Pb exposure. It was shown that co-exposure induced cellular production of reactive oxygen species (ROS, increased to 134.4 %) disrupted the antioxidant system of earthworm body cavity cells, activated superoxide dismutase and catalase (CAT), produced reduced glutathione, and inhibited glutathione-dependent enzyme (GST) activity (Reduced to 64 %). Total antioxidant capacity (T-AOC) is first enhanced against ROS due to the stress of NPs and Pb. When the antioxidant reserves of cells are exhausted, the antioxidant capacity will decrease. The level of malondialdehyde, a biomarker of eventual lipid peroxidation, increased to 231.7 %. At the molecular level, due to co-exposure to NPs and Pb, CAT was loosely structured and the secondary structure is misfolded, which was responsible for exacerbating oxidative damage in E. fetida coelomocytes. The findings of this study have significant implications for the toxicological interaction and future risk assessment of co-contamination of NPs and Pb in the environment.

Toxic effects and mechanisms of nanoplastics on embryonic brain development using brain organoids model

Nanoplastics can be easily absorbed into the human body through inhalation, ingestion, and skin contact due to their physicochemical property. Despite the numerous studies postulating the potential adverse effects of environmental exposure to nanoplastics on neurodevelopment, the effects of nanoplastics and their regulatory mechanisms have not been specifically elucidated. We focused on the toxic effects of nanoplastics on brain developmental processes by investigating their interactions with brain organoids. Our findings indicated that nanoplastics exposure caused cellular dysfunction and structural disorders. Nanoplastics adversely affected critical cells in brain organoids, resulting in the reduction of neural precursor cells and neuronal cells. The expression of neural cadherin was also inhibited, which might lead to impaired axonal extension and formation of synaptic connections. In addition, transcriptome sequencing was performed to study the effects of different concentrations of nanoplastics on the signaling pathway. The qRT-PCR analysis confirmed that nanoplastics exposure resulted in decreased expression of several genes related to the Wnt signaling pathway, suggesting that nanoplastics may adversely affect embryonic brain growth through the suppression of the expression of these genes. Our research findings shed light on the deleterious effects of nanoplastics on embryonic brain development and have significant implications for the field of environmental toxicology.

Polystyrene nanoplastic exposure induces excessive mitophagy by activating AMPK/ULK1 pathway in differentiated SH-SY5Y cells and dopaminergic neurons in vivo

BACKGROUND

Microplastics and nanoplastics (MNPs) are emerging environmental contaminants detected in human samples, and have raised concerns regarding their potential risks to human health, particularly neurotoxicity. This study aimed to investigate the deleterious effects of polystyrene nanoplastics (PS-NPs, 50 nm) and understand their mechanisms in inducing Parkinson's disease (PD)-like neurodegeneration, along with exploring preventive strategies.

METHODS

Following exposure to PS-NPs (0.5-500 μg/mL), we assessed cytotoxicity, mitochondrial integrity, ATP levels, and mitochondrial respiration in dopaminergic-differentiated SH-SY5Y cells. Molecular docking and dynamic simulations explored PS-NPs' interactions with mitochondrial complexes. We further probed mitophagy's pivotal role in PS-NP-induced mitochondrial damage and examined melatonin's ameliorative potential in vitro. We validated melatonin's intervention (intraperitoneal, 10 mg/kg/d) in C57BL/6 J mice exposed to 250 mg/kg/d of PS-NPs for 28 days.

RESULTS

In our in vitro experiments, we observed PS-NP accumulation in cells, including mitochondria, leading to cell toxicity and reduced viability. Notably, antioxidant treatment failed to fully rescue viability, suggesting reactive oxygen species (ROS)-independent cytotoxicity. PS-NPs caused significant mitochondrial damage, characterized by altered morphology, reduced mitochondrial membrane potential, and decreased ATP production. Subsequent investigations pointed to PS-NP-induced disruption of mitochondrial respiration, potentially through interference with complex I (CI), a concept supported by molecular docking studies highlighting the influence of PS-NPs on CI. Rescue experiments using an AMPK pathway inhibitor (compound C) and an autophagy inhibitor (3-methyladenine) revealed that excessive mitophagy was induced through AMPK/ULK1 pathway activation, worsening mitochondrial damage and subsequent cell death in differentiated SH-SY5Y cells. Notably, we identified melatonin as a potential protective agent, capable of alleviating PS-NP-induced mitochondrial dysfunction. Lastly, our in vivo experiments demonstrated that melatonin could mitigate dopaminergic neuron loss and motor impairments by restoring mitophagy regulation in mice.

CONCLUSIONS

Our study demonstrated that PS-NPs disrupt mitochondrial function by affecting CI, leading to excessive mitophagy through the AMPK/ULK1 pathway, causing dopaminergic neuron death. Melatonin can counteract PS-NP-induced mitochondrial dysfunction and motor impairments by regulating mitochondrial autophagy. These findings offer novel insights into the MNP-induced PD-like neurodegenerative mechanisms, and highlight melatonin's protective potential in mitigating the MNP's environmental risk.

Anionic nanoplastic contaminants promote Parkinson's disease-associated α-synuclein aggregation

Recent studies have identified increasing levels of nanoplastic pollution in the environment. Here, we find that anionic nanoplastic contaminants potently precipitate the formation and propagation of α-synuclein protein fibrils through a high-affinity interaction with the amphipathic and non-amyloid component (NAC) domains in α-synuclein. Nanoplastics can internalize in neurons through clathrin-dependent endocytosis, causing a mild lysosomal impairment that slows the degradation of aggregated α-synuclein. In mice, nanoplastics combine with α-synuclein fibrils to exacerbate the spread of α-synuclein pathology across interconnected vulnerable brain regions, including the strong induction of α-synuclein inclusions in dopaminergic neurons in the substantia nigra. These results highlight a potential link for further exploration between nanoplastic pollution and α-synuclein aggregation associated with Parkinson's disease and related dementias.

Interaction between antibiotics and microplastics: Recent advances and perspective

Both microplastics and antibiotics are emerging pollutants, which are ubiquitous in aquatic environments. With small size, high specific surface area, and attached biofilm, microplastics are capable of adsorbing or biodegrading antibiotic pollutants across aquatic environments. However, the interactions between them are poorly understood, especially factors that affect microplastics' chemical vector effects and the mechanisms driving these interactions. In this review, the properties of microplastics and their interaction behavior and mechanisms towards antibiotics were comprehensively summarized. Particularly, the impact of weathering properties of microplastics and the growth of attached biofilm was highlighted. We concluded that compared with virgin microplastics, aged microplastics usually adsorb more types and quantities of antibiotics from aquatic environments, whilst the attached biofilm could further enhance the adsorption capacities and biodegrade some antibiotics. This review can answer the knowledge gaps of the interaction between microplastics and antibiotics (or other pollutants), offer basic information for evaluating their combined toxicity, provide insights into the distribution of both emerging pollutants in the global water chemical cycle, and inform measures to remove microplastic-antibiotic pollution.

Anionic Nanoplastic Contaminants Promote Parkinson's Disease-Associated α-Synuclein Aggregation

Recent studies have identified increasing levels of nanoplastic pollution in the environment. Here we find that anionic nanoplastic contaminants potently precipitate the formation and propagation of α-synuclein protein fibrils through a high-affinity interaction with the amphipathic and non-amyloid component (NAC) domains in α-synuclein. Nanoplastics can internalize in neurons through clathrin-dependent endocytosis, causing a mild lysosomal impairment that slows the degradation of aggregated α-synuclein. In mice, nanoplastics combine with α-synuclein fibrils to exacerbate the spread of α-synuclein pathology across interconnected vulnerable brain regions, including the strong induction of α-synuclein inclusions in dopaminergic neurons in the substantia nigra. These results highlight a potential link for further exploration between nanoplastic pollution and α-synuclein aggregation associated with Parkinson's disease and related dementias.

Mechanistic Understanding toward the Maternal Transfer of Nanoplastics in Daphnia magna

Nanoplastics induce transgenerational toxicity to aquatic organisms, but the specific pathways for the maternal transfer of nanoplastics remain unclear. Herein, laser scanning confocal microscopy (LSCM) observations identified the specific pathways on the maternal transfer of polystyrene (PS) nanoplastics (25 nm) in Daphnia magna. In vivo and in vitro experiments showed that PS nanoplastics could enter the brood chamber through its opening and then be internalized to eggs and embryos using LSCM imaging (pathway I). In addition, PS nanoplastics were observed in the oocytes of the ovary, demonstrating gut-ovary-oocyte transfer (pathway II). Furthermore, label-free hyperspectral imaging was used to detect the distribution of nanoplastics in the embryos and ovary of Daphnia, again confirming the maternal transfer of nanoplastics through the two pathways mentioned above. The contribution from pathway I (88%) was much higher than pathway II (12%) based on nanoflow cytometry quantification. In addition, maternal transfer in Daphnia depended on the particle size of PS nanoplastics, as demonstrated by using LSCM and hyperspectral imaging. Unlike 25 nm nanoplastics, 50 nm PS nanoplastics could enter the brood chamber and the eggs/embryos (pathway I), but were not detected in the ovary (pathway II); 100 nm PS nanoplastics were difficult to be internalized by eggs/embryos and could not enter the ovary either. These findings provide insight into the maternal transfer mechanisms of nanoplastics in Daphnia, and are critical for better understanding the transgenerational toxicity of aquatic organisms.

Long-Chain Acyl Carnitines Aggravate Polystyrene Nanoplastics-Induced Atherosclerosis by Upregulating MARCO

Exposure to micro- and nanoplastics (MNPs) is common because of their omnipresence in environment. Recent studies have revealed that MNPs may cause atherosclerosis, but the underlying mechanism remains unclear. To address this bottleneck, ApoE^-/- mice are exposed to 2.5-250 mg kg^-1 polystyrene nanoplastics (PS-NPs, 50 nm) by oral gavage with a high-fat diet for 19 weeks. It is found that PS-NPs in blood and aorta of mouse exacerbate the artery stiffness and promote atherosclerotic plaque formation. PS-NPs activate phagocytosis of M1-macrophage in the aorta, manifesting as upregulation of macrophage receptor with collagenous structure (MARCO). Moreover, PS-NPs disrupt lipid metabolism and increase long-chain acyl carnitines (LCACs). LCAC accumulation is attributed to the PS-NP-inhibited hepatic carnitine palmitoyltransferase 2. PS-NPs, as well as LCACs alone, aggravate lipid accumulation via upregulating MARCO in the oxidized low-density lipoprotein-activated foam cells. Finally, synergistic effects of PS-NPs and LCACs on increasing total cholesterol in foam cells are found. Overall, this study indicates that LCACs aggravate PS-NP-induced atherosclerosis by upregulating MARCO. This study offers new insight into the mechanisms underlying MNP-induced cardiovascular toxicity, and highlights the combined effects of MNPs with endogenous metabolites on the cardiovascular system, which warrant further study.

Effects of true-to-life PET nanoplastics using primary human nasal epithelial cells

Since inhalation is a relevant exposure route, studies using appropriate micro/nanoplastic (MNPLs) models, representative targeted cells, and relevant biomarkers of effect are required. We have used lab-made polyethylene terephthalate (PET)NPLs obtained from PET plastic water bottles. Human primary nasal epithelial cells (HNEpCs) were used as a model of the first barrier of the respiratory system. Cell internalization and intracellular reactive oxygen species (iROS) induction, as well as the effects on mitochondria functionality and in the modulation of the autophagy pathway, were evaluated. The data indicated significant cellular uptake and increased levels of iROS. Furthermore, a loss of mitochondrial membrane potential was observed in the exposed cells. Regarding the effects on the autophagy pathway, PETNPLs exposure significantly increases LC3-II protein expression levels. PETNPLs exposure also induced significant increases in the expression of p62. This is the first study showing that true-to-life PETNPLs can alter the autophagy pathway in HNEpCs.

Potential lifetime effects caused by cellular uptake of nanoplastics: A review

Plastics have been used for about 100 years, and daily-use products composed of plastics are now prevalent. As a result, humans are very easily exposed to the plastic particles generated from the daily-use plastics. However, studies on cellular uptake of nanoplastics in "human cells" have only recently begun to attract attention. In previous studies, definitions of nanoplastics and microplastics were vague, but recently, they have been considered to be different and are being studied separately. However, nanoplastics, unlike plastic particles of other sizes such as macro- and microplastics, can be absorbed by human cells, and thus can cause various risks such as cytotoxicity, inflammation, oxidative stress, and even diseases such as cancer^{82, 83.} and diabetes (Fan et al., 2022; Wang et al., 2023). Thus, in this review, we defined microplastics and nanoplastics to be different and described the potential risks of nanoplastics to human caused by cellular uptake according to their diverse factors. In addition, during and following plastic product usage a substantial number of fragments of different sizes can be generated, including nanoplastics. Fragmentation of microplastics into nanoplastics may also occur during ingestion and inhalation, which can potentially cause long-term hazards to human health. However, there are still few in vivo studies conducted on the health effect of nanoplastics ingestion and inhalation.

Lysosomal nanotoxicity: Impact of nanomedicines on lysosomal function

Although several nanomedicines got clinical approval over the past two decades, the clinical translation rate is relatively small so far. There are many post-surveillance withdrawals of nanomedicines caused by various safety issues. For successful clinical advancement of nanotechnology, it is of unmet need to realize cellular and molecular foundation of nanotoxicity. Current data suggest that lysosomal dysfunction caused by nanoparticles is emerging as the most common intracellular trigger of nanotoxicity. This review analyzes prospect mechanisms of lysosomal dysfunction-mediated toxicity induced by nanoparticles. We summarized and critically assessed adverse drug reactions of current clinically approved nanomedicines. Importantly, we show that physicochemical properties have great impact on nanoparticles interaction with cells, excretion route and kinetics, and subsequently on toxicity. We analyzed literature on adverse reactions of current nanomedicines and hypothesized that adverse reactions might be linked with lysosomal dysfunction caused by nanomedicines. Finally, from our analysis it becomes clear that it is unjustifiable to generalize safety and toxicity of nanoparticles, since different particles possess distinct toxicological properties. We propose that the biological mechanism of the disease progression and treatment should be central in the optimization of nanoparticle design.

Unveiling Distribution of Per- and Polyfluoroalkyl Substances in Matched Placenta-Serum Tetrads: Novel Implications for Birth Outcome Mediated by Placental Vascular Disruption

The placenta is pivotal for fetal development and maternal-fetal transfer of many substances, including per- and polyfluoroalkyl substances (PFASs). However, the intraplacental distribution of PFASs and their effects on placental vascular function remain unclear. In this study, 302 tetrads of matched subchorionic placenta (fetal-side), parabasal placenta (maternal-side), cord serum, and maternal serum samples were collected from Guangzhou, China. Eighteen emerging and legacy PFASs and five placental vascular biomarkers were measured. Results showed that higher levels of perfluorooctanoic (PFOA), perfluorooctane sulfonic acid (PFOS), and chlorinated polyfluorinated ether sulfonic acids (Cl-PFESAs) were detected in subchorionic placenta compared to parabasal placenta. There were significant associations of PFASs in the subchorionic placenta, but not in the serum, with placental vascular biomarkers (up to 32.5%) and lower birth size. Birth weight was negatively associated with PFOA (β: -103.8, 95% CI: -186.3 and -21.32) and 6:2 Cl-PFESA (β: -80.04, 95% CI: -139.5 and -20.61), primarily in subchorionic placenta. Mediation effects of altered placental angiopoietin-2 and vascular endothelial growth factor receptor-2 were evidenced on associations of adverse birth outcomes with intraplacental PFOS and 8:2 Cl-PFESA, explaining 9.5%-32.5% of the total effect. To the best of our knowledge, this study is the first to report on differential intraplacental distribution of PFASs and placental vascular effects mediating adverse birth outcomes and provides novel insights into the placental plate-specific measurement in PFAS-associated health risk assessment.

Nanoplastic-induced vascular endothelial injury and coagulation dysfunction in mice

Nanoplastics are the persistent pollutants in a variety of environments, representing a potential threat to human health. Notably, plastic particles have been detected in sample of human bloodstream. It is thus significant to investigate the effects of nanoplastics on the cardiovascular system owing to its ease transfer through the bloodstream to other organs. However, few studies have been performed to evaluate the cardiovascular toxicity of nanoplastics. Herein, we pursued to investigate the adverse cardiovascular impacts of polystyrene (PS), PS-NH₂ and PS-COOH nanoplastics on mice. Experimental results demonstrated that the exposure to these nanoplastics could result in structural damage of vascular endothelial cells and inflammatory response. Moreover, it was found out that the dysfunctions of coagulation and prethrombotic state were caused by nanoplastics, which could be ascribed to the activation of JAK1/STAT3/TF signaling pathway. In summary, results clearly indicated that nanoplastic exposure lead to vascular toxicity to mice, which serves as a basis for future studies about the potential physiological threat of nanoplastics to humans.

Small Plastics, Big Inflammatory Problems

The immune system is the first defense against potentially dangerous chemicals, infections, and damaged cells. Interactions between immune cells and inflammatory mediators increase the coordinated activation of cross-talking signaling pathways, resulting in an acute response necessary to restore homeostasis but potentially detrimental if uncontrolled and prolonged. Plastic production exceeds million tons per year, becoming a global concern due to the stability of its constituent polymers, low density, which allows them to spread easily, and small size, which prevents proper removal by wastewater treatment plants, promoting environmental accumulation and increasing health threats. The interaction between plastic particles and the immune system is still being investigated, owing to growing evidence of increased risk not only for dietary intake due to its presence in food packaging, drinking water, and even fruits and vegetables, but also to emerging evidence of new intake pathways such as respiratory and cutaneous. We discuss in depth the impact of small plastic particles on the immune response across the body, with a focus on the nervous system and peripheral organs and tissues such as the gastrointestinal, respiratory, lymphatic, cardiovascular, and reproductive systems, as well as the involvement in increased susceptibility to worsening concomitant diseases and future perspectives in the exploration of potential therapeutics.

Unraveling the potential human health risks from used disposable face mask-derived micro/nanoplastics during the COVID-19 pandemic scenario: A critical review

With the global spread of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), disposable face masks (DFMs) have caused negative environmental impacts. DFMs will release microplastics (MPs) and nanoplastics (NPs) during environmental degradation. However, few studies reveal the release process of MPs/NPs from masks in the natural environment. This review presents the current knowledge on the abiotic and biotic degradation of DFMs. Though MPs and NPs have raised serious concerns about their potentially detrimental effects on human health, little attention was paid to their impacts on human health from DFM-derived MPs and NPs. The potential toxicity of mask-derived MPs/NPs, such as gastrointestinal toxicity, pneumotoxicity, neurotoxicity, hepatotoxicity, reproductive and transgenerational toxicity, and the underlying mechanism will be discussed in the present study. MPs/NPs serve as carriers of toxic chemicals and pathogens, leading to their bioaccumulation and adverse effects of biomagnification by food chains. Given human experiments are facing ethical issues and animal studies cannot completely reveal human characteristics, advanced human organoids will provide promising models for MP/NP risk assessment. Moreover, in-depth investigations are required to identify the release of MPs/NPs from discarded face masks and characterize their transportation through the food chains. More importantly, innovative approaches and eco-friendly strategies are urgently demanded to reduce DFM-derived MP/NP pollution.