Amorphous silica nanoparticles accelerated atherosclerotic lesion progression in ApoE-/- mice through endoplasmic reticulum stress-mediated CD36 up-regulation in macrophage

Targeting macrophages with multifunctional nanoparticles to detect and prevent atherosclerotic cardiovascular disease

Despite the emergence of novel diagnostic, pharmacological, interventional, and prevention strategies, atherosclerotic cardiovascular disease remains a significant cause of morbidity and mortality. Nanoparticle (NP)-based platforms encompass diverse imaging, delivery, and pharmacological properties that provide novel opportunities for refining diagnostic and therapeutic interventions for atherosclerosis at the cellular and molecular levels. Macrophages play a critical role in atherosclerosis and therefore represent an important disease-related diagnostic and therapeutic target, especially given their inherent ability for passive and active NP uptake. In this review, we discuss an array of inorganic, carbon-based, and lipid-based NPs that provide magnetic, radiographic, and fluorescent imaging capabilities for a range of highly promising research and clinical applications in atherosclerosis. We discuss the design of NPs that target a range of macrophage-related functions such as lipoprotein oxidation, cholesterol efflux, vascular inflammation, and defective efferocytosis. We also provide examples of NP systems that were developed for other pathologies such as cancer and highlight their potential for repurposing in cardiovascular disease. Finally, we discuss the current state of play and the future of theranostic NPs. Whilst this is not without its challenges, the array of multifunctional capabilities that are possible in NP design ensures they will be part of the next frontier of exciting new therapies that simultaneously improve the accuracy of plaque diagnosis and more effectively reduce atherosclerosis with limited side effects.

Maleic anhydride-functionalized cellulose nanocrystal-stabilized high internal phase Pickering emulsion for pesticide delivery

The salt-responsiveness of Pickering emulsions has significantly influenced their applications due to the large amount of salt on the surface of plant leaves. The present study provided a maleic anhydride-functionalized cellulose nanocrystal-stabilized high internal phase Pickering emulsion (MACNCs-HIPPEs) that was stable to high-concentration salt and used for pesticide delivery. The stability of MACNCs-HIPPEs was investigated by adjusting the oil-phase volume fraction (φ), the MACNCs concentration, NaCl dosages, and the rheological properties. The high internal phase Pickering emulsion was obtained at φ of 0.8 and MACNCs concentration of 2wt% and showed excellent salt stability (NaCl, 1200 mM) and significant storage stability (60 days). The sustained release of imidacloprid (IMI) from imidacloprid-loaded MACNCs-HIPPEs (IMI@MACNCs-HIPPEs) showed a positive correlation to the temperature (15°C, 25°C, 35°C), indicating clear thermo-responsiveness of the prepared pesticide formulation. The test of spread and retention of IMI@MACNCs-HIPPEs on the leaf surface showed a significant advantage compared with the commercial IMI water dispersible granules (CG). All the advantages mentioned above showed the excellent potential of the MACNCs-HIPPEs in delivering lipophilic pesticides.

Epithelium-derived exosomes promote silica nanoparticles-induced pulmonary fibroblast activation and collagen deposition via modulating fibrotic signaling pathways and their epigenetic regulations

BACKGROUND

In the context of increasing exposure to silica nanoparticles (SiNPs) and ensuing respiratory health risks, emerging evidence has suggested that SiNPs can cause a series of pathological lung injuries, including fibrotic lesions. However, the underlying mediators in the lung fibrogenesis caused by SiNPs have not yet been elucidated.

RESULTS

The in vivo investigation verified that long-term inhalation exposure to SiNPs induced fibroblast activation and collagen deposition in the rat lungs. In vitro, the uptake of exosomes derived from SiNPs-stimulated lung epithelial cells (BEAS-2B) by fibroblasts (MRC-5) enhanced its proliferation, adhesion, and activation. In particular, the mechanistic investigation revealed SiNPs stimulated an increase of epithelium-secreted exosomal miR-494-3p and thereby disrupted the TGF-β/BMPR2/Smad pathway in fibroblasts via targeting bone morphogenetic protein receptor 2 (BMPR2), ultimately resulting in fibroblast activation and collagen deposition. Conversely, the inhibitor of exosomes, GW4869, can abolish the induction of upregulated miR-494-3p and fibroblast activation in MRC-5 cells by the SiNPs-treated supernatants of BEAS-2B. Besides, inhibiting miR-494-3p or overexpression of BMPR2 could ameliorate fibroblast activation by interfering with the TGF-β/BMPR2/Smad pathway.

CONCLUSIONS

Our data suggested pulmonary epithelium-derived exosomes serve an essential role in fibroblast activation and collagen deposition in the lungs upon SiNPs stimuli, in particular, attributing to exosomal miR-494-3p targeting BMPR2 to modulate TGF-β/BMPR2/Smad pathway. Hence, strategies targeting exosomes could be a new avenue in developing therapeutics against lung injury elicited by SiNPs.

Cardiovascular toxic effects of nanoparticles and corresponding molecular mechanisms

Rapid advancements in nanotechnology have been integrated into various disciplines, leading to an increased prevalence of nanoparticle exposure. The widespread utilization of nanomaterials and heightened levels of particulate pollution have prompted government departments to intensify their focus on assessing the safety of nanoparticles (NPs). The cardiovascular system, crucial for maintaining human health, has emerged as vulnerable to damage from nanoparticle exposure. A mounting body of evidence indicates that interactions can occur when NPs come into contact with components of the cardiovascular system, contributing to adverse cardiovascular disease (CVD). However, the underlying molecular mechanisms driving these events remain elusive. This work provides a comprehensive review of recent advance on nanoparticle-induced adverse cardiovascular events and offers insight into the associated molecular mechanisms. Finally, the influencing factors of NPs-induced cardiovascular toxicity are discussed.

M1/M2 macrophage-targeted nanotechnology and PROTAC for the treatment of atherosclerosis

Macrophages play key roles in atherosclerosis progression, and an imbalance in M1/M2 macrophages leads to unstable plaques; therefore, M1/M2 macrophage polarization-targeted treatments may serve as a new approach in the treatment of atherosclerosis. At present, there is little research on M1/M2 macrophage polarization-targeted nanotechnology. Proteolysis-targeting chimera (PROTAC) technology, a targeted protein degradation technology, mediates the degradation of target proteins and has been widely promoted in preclinical and clinical applications as a novel therapeutic modality. This review summarizes the recent studies on M1/M2 macrophage polarization-targeted nanotechnology, focusing on the mechanism and advantages of PROTACs in M1/M2 macrophage polarization as a new approach for the treatment of atherosclerosis.

Associations of coal mine dust exposure with arterial stiffness and atherosclerotic cardiovascular disease risk in chinese coal miners

OBJECTIVE

Whether coal mine dust exposure increases cardiovascular diseases (CVDs) risk was rarely explored. Our objective was to examine the association between coal mine dust exposure and cardiovascular risk.

METHODS

We estimated cumulative coal mine dust exposure (CDE) for 1327 coal miners by combining data on workplace dust concentrations and work history. We used brachial-ankle pulse wave velocity (baPWV, a representative indicator of arterial stiffness) and ten-year atherosclerotic cardiovascular disease (ASCVD) risk to assess potential CVD risk, exploring their associations with CDE.

RESULTS

Positive dose-response relationships of CDE with baPWV and ten-year ASCVD risk were observed after adjusting for covariates. Specifically, each 1 standard deviation (SD) increase in CDE was related to a 0.27 m/s (95% CI: 0.21, 0.34) increase in baPWV and a 1.29 (95% CI: 1.14, 1.46) elevation in OR (odds ratio) of risk of abnormal baPWV. Moreover, each 1 SD increase in CDE was associated with a 0.74% (95% CI: 0.63%, 0.85%) increase in scores of ten-year ASCVD and a 1.91 (95% CI: 1.62, 2.26) increase in OR of risk of ten-year ASCVD. When compared with groups unexposed to coal mine dust, significant increase in the risk of arterial stiffness and ten-year ASCVD in the highest CDE groups were detected.

CONCLUSION

The study suggested that cumulative exposure to coal mine dust was associated with elevated arterial stiffness and ten-year ASCVD risk in a dose-response manner. These findings contribute valuable insights for cardiovascular risk associated with coal mine dust.

Proteomics revealed composition- and size-related regulators for hepatic impairments induced by silica nanoparticles

Along with the growing production and application of silica nanoparticles (SiNPs), increased human exposure and ensuing safety evaluation have progressively attracted concern. Accumulative data evidenced the hepatic injuries upon SiNPs inhalation. Still, the understanding of the hepatic outcomes resulting from SiNPs exposure, and underlying mechanisms are incompletely elucidated. Here, SiNPs of two sizes (60 nm and 300 nm) were applied to investigate their composition- and size-related impacts on livers of ApoE-/- mice via intratracheal instillation. Histopathological and biochemical analysis indicated SiNPs promoted inflammation, lipid deposition and fibrosis in the hepatic tissue, accompanied by increased ALT, AST, TC and TG. Oxidative stress was activated upon SiNPs stimuli, as evidenced by the increased hepatic ROS, MDA and declined GSH/GSSG. Of note, these alterations were more dramatic in SiNPs with a smaller size (SiNPs-60) but the same dosage. LC-MS/MS-based quantitative proteomics unveiled changes in mice liver protein profiles, and filtered out particle composition- or size-related molecules. Interestingly, altered lipid metabolism and oxidative damage served as two critical biological processes. In accordance with correlation analysis and liver disease-targeting prediction, a final of 10 differentially expressed proteins (DEPs) were selected as key potential targets attributable to composition- (4 molecules) and size-related (6 molecules) liver impairments upon SiNPs stimuli. Overall, our study provided strong laboratory evidence for a comprehensive understanding of the harmful biological effects of SiNPs, which was crucial for toxicological evaluation to ensure nanosafety.

Ferroptosis contributing to cardiomyocyte injury induced by silica nanoparticles via miR-125b-2-3p/HO-1 signaling

BACKGROUND

Amorphous silica nanoparticles (SiNPs) have been gradually proven to threaten cardiac health, but pathogenesis has not been fully elucidated. Ferroptosis is a newly defined form of programmed cell death that is implicated in myocardial diseases. Nevertheless, its role in the adverse cardiac effects of SiNPs has not been described.

RESULTS

We first reported the induction of cardiomyocyte ferroptosis by SiNPs in both in vivo and in vitro. The sub-chronic exposure to SiNPs through intratracheal instillation aroused myocardial injury, characterized by significant inflammatory infiltration and collagen hyperplasia, accompanied by elevated CK-MB and cTnT activities in serum. Meanwhile, the activation of myocardial ferroptosis by SiNPs was certified by the extensive iron overload, declined FTH1 and FTL, and lipid peroxidation. The correlation analysis among detected indexes hinted ferroptosis was responsible for the SiNPs-aroused myocardial injury. Further, in vitro tests, SiNPs triggered iron overload and lipid peroxidation in cardiomyocytes. Concomitantly, altered expressions of TfR, DMT1, FTH1, and FTL indicated dysregulated iron metabolism of cardiomyocytes upon SiNP stimuli. Also, shrinking mitochondria with ridge fracture and ruptured outer membrane were noticed. To note, the ferroptosis inhibitor Ferrostatin-1 could effectively alleviate SiNPs-induced iron overload, lipid peroxidation, and myocardial cytotoxicity. More importantly, the mechanistic investigations revealed miR-125b-2-3p-targeted HO-1 as a key player in the induction of ferroptosis by SiNPs, probably through regulating the intracellular iron metabolism to mediate iron overload and ensuing lipid peroxidation.

CONCLUSIONS

Our findings firstly underscored the fact that ferroptosis mediated by miR-125b-2-3p/HO-1 signaling was a contributor to SiNPs-induced myocardial injury, which could be of importance to elucidate the toxicity and provide new insights into the future safety applications of SiNPs-related nano products.

State of the Art of Silica Nanoparticles: An Overview on Biodistribution and Preclinical Toxicity Studies

Over the past few years, nanoparticles have drawn particular attention in designing and developing drug delivery systems due to their distinctive advantages like improved pharmacokinetics, reduced toxicity, and specificity. Along with other successful nanosystems, silica nanoparticles (SNPs) have shown promising effects for therapeutic and diagnostic purposes. These nanoparticles are of great significance owing to their modifiable surface with various ligands, tunable particle size, and large surface area. The rate and extent of degradation and clearance of SNPs depend on factors such as size, shape, porosity, and surface modification, which directly lead to varying toxic mechanisms. Despite SNPs' enormous potential for clinical and pharmaceutical applications, safety concerns have hindered their translation into the clinic. This review discusses the biodistribution, toxicity, and clearance of SNPs and the formulation-related factors that ultimately influence clinical efficacy and safety for treatment. A holistic view of SNP safety will be beneficial for developing an enabling SNP-based drug product.

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.

Lipidomics Investigation Reveals the Reversibility of Hepatic Injury by Silica Nanoparticles in Rats After a 6-Week Recovery Duration

Given the inevitable human exposure owing to its increasing production and utilization, the comprehensive safety evaluation of silica nanoparticles (SiNPs) has sparked concerns. Substantial evidence indicated liver damage by inhaled SiNPs. Notwithstanding, few reports focused on the persistence or reversibility of hepatic injuries, and the intricate molecular mechanisms involved remain limited. Here, rats are intratracheally instilled with SiNPs in two regimens (a 3-month exposure and a subsequent 6-week recovery after terminating SiNPs administration) to assess the hepatic effects. Nontargeted lipidomics revealed alterations in lipid metabolites as a contributor to the hepatic response and recovery effects of SiNPs. In line with the functional analysis of differential lipid metabolites, SiNPs activated oxidative stress, and induced lipid peroxidation and lipid deposition in the liver, as evidenced by the elevated hepatic levels of ROS, MDA, TC, and TG. Of note, these indicators showed great improvements after a 6-week recovery, even returning to the control levels. According to the correlation, ROC curve, and SEM analysis, 11 lipids identified as potential regulatory molecules for ameliorating liver injury by SiNPs. Collectively, the work first revealed the reversibility of SiNP-elicited hepatotoxicity from the perspective of lipidomics and offered valuable laboratory evidence and therapeutic strategy to facilitate nanosafety.

Prospects and hazards of silica nanoparticles: Biological impacts and implicated mechanisms

With the thrive of nanotechnology, silica nanoparticles (SiNPs) have been extensively adopted in the agriculture, food, cosmetic, and even biomedical industries. Due to the mass production and use, SiNPs inevitably entered the environment, resulting in ecological toxicity and even posing a threat to human health. Although considerable investigations have been conducted to assess the toxicity of SiNPs, the correlation between SiNPs exposure and consequent health risks remains ambiguous. Since the biological impacts of SiNPs can differ from their design and application, the toxicity assessment for SiNPs may be extremely difficult. This review discussed the application of SiNPs in different fields, especially their biomedical use, and documented their potential release pathways into the environment. Meanwhile, the current process of assessing SiNPs-related toxicity on various model organisms and cell lines was also detailed, thus estimating the health threats posed by SiNPs exposure. Finally, the potential toxic mechanisms of SiNPs were also elaborated based on results obtained from both in vivo and in vitro trials. This review generally summarizes the biological effects of SiNPs, which will build up a comprehensive perspective of the application and toxicity of SiNPs.

Silica nanoparticles promoted pro-inflammatory macrophage and foam cell transformation via ROS/PPARγ/NF-κB signaling

Experimental evidence has pointed out silica nanoparticles (SiNPs) possessing a proatherogenic capability. However, the interplay between SiNPs and macrophages in the pathogenesis of atherosclerosis was poorly understood. Here, we demonstrated SiNPs could promote macrophage adhesion to endothelial cells, accompanied by elevated Vcam1 and Mcp1. Upon SiNPs stimuli, macrophages manifested enhanced phagocytic activity and a pro-inflammatory phenotype, as reflected by the transcriptional determination of M1/M2-related biomarkers. In particular, our data certified the increased macrophage M1 subset facilitated more lipid accumulation and resultant foam cell transformation in comparison to the M2 phenotype. More importantly, the mechanistic investigations revealed ROS-mediated PPARγ/NF-κB signaling was a key contributor to the above phenomena. That was, SiNPs caused ROS accumulation in macrophages, resulting in the deactivation of PPARγ, nuclear translocation of NF-κB, ultimately contributing to macrophage phenotype shift toward M1 and foam cell transformation. Collectively, we first revealed SiNPs facilitated pro-inflammatory macrophage and foam cell transformation via ROS/PPARγ/NF-κB signaling. These data would provide new insight into the atherogenic property of SiNPs in a macrophage model.

MPA-capped CdTequantum dots induces endoplasmic reticulum stress-mediated autophagy and apoptosis through generation of reactive oxygen species in human liver normal cell and liver tumor cell

The rapid developments in nanotechnology have brought increased attention to the safety of Quantum Dots (QDs). Exploring their mechanisms of toxicity and characterizing their toxic effects in different cell lines will help us better understand and apply QDs appropriately. This study aims to elucidate the importance of reactive oxygen species (ROS) and endoplasmic reticulum (ER) stress-induced autophagy for CdTe QDs toxicity, that is, the importance of the nanoparticles in mediating cellular uptake and consequent intracellular stress effects inside the cell. The results of the study showed that cancer cells and normal cells have different cell outcomes as a result of intracellular stress effects. In normal human liver cells (L02), CdTe QDs leads to ROS generation and prolong ER stress. The subsequent autophagosome accumulation eventually triggers apoptosis by activating proapoptotic signaling pathways and the expression of proapoptotic Bax. In contrast, in human liver cancer cells (HepG2 cells), expression of UPR restrains proapoptotic signaling and downregulates Bax, and activated protective cellular autophagy, as a result of protecting these liver cancer cells from CdTe QDs-induced apoptosis. In summary, we assess the safety of CdTe QDs and recounted the molecular mechanism underlying its nanotoxicity in normal and cancerous cells. Notwithstanding, additional detailed studies on the deleterious effects of these nanoparticles in the organisms of interest are required to ensure low-risk application.

Insights into the toxicological effects of nanomaterials on atherosclerosis: mechanisms involved and influence factors

Atherosclerosis is one of the most common types of cardiovascular disease and is driven by lipid accumulation and chronic inflammation in the arteries, which leads to stenosis and thrombosis. Researchers have been working to design multifunctional nanomedicines with the ability to target, diagnose, and treat atherosclerosis, but recent studies have also identified that nanomaterials can cause atherosclerosis. Therefore, this review aims to outline the molecular mechanisms and physicochemical properties of nanomaterials that promote atherosclerosis. By analyzing the toxicological effects of nanomaterials on cells involved in the pathogenesis of atherosclerosis such as vascular endothelial cells, vascular smooth muscle cells and immune cells, we aim to provide new perspectives for the prevention and treatment of atherosclerosis, and raise awareness of nanotoxicology to advance the clinical translation and sustainable development of nanomaterials.

Long-term exposure of molybdenum disulfide nanosheets leads to hepatic lipid accumulation and atherogenesis in apolipoprotein E deficient mice

Before their large-scale applications, it is necessary to understand the biological effects of nanomaterials. Although two-dimensional nanomaterials (2D NMs) molybdenum disulfide nanosheets (MoS₂ NSs) are promising in biomedical fields, the current knowledge regarding their toxicities is inadequate. Using apolipoprotein E deficient (ApoE^-/-) mice as a long-term exposure model, this study demonstrated that intravenous (i.v.) injection of MoS₂ NSs most accumulated in the liver and caused in situ hepatic damage. Histopathological examination indicated severe infiltration of inflammatory cells and irregular central veins in the MoS₂ NSs-treated mouse liver. Meanwhile, the overwhelming expressions of inflammatory cytokines, dyslipidemia, and dysregulated hepatic lipid metabolism implied the potential vascular toxicity of MoS₂ NSs. Indeed, our result supported that MoS₂ NSs exposure is highly associated with atherosclerotic progression. This study provided the first line of evidence on the vascular toxicity of MoS₂ NSs, which remind scientists to pay attention to the rational use of MoS₂ NSs, especially in the biomedical fields.

SiNPs induce ferroptosis in HUVECs through p38 inhibiting NrF2 pathway

Introduction

Despite of growing evidence linking silica nanoparticles (SiNPs), one of the global-top-three-produced and -used nanoparticle (NP), to human health risks, there remain many knowledge gaps over the adverse effects of SiNPs exposure on cardiovascular system and the underlying molecular mechanisms.

Methods

In this study, the ferroptotic effects of SiNPs (20 nm; 0, 25, 50, and 100 μg/mL) on human umbilical vein endothelial cells (HUVECs) and the possible molecular mechanism were studied with the corresponding biochemical and molecular biology assays.

Results and discussion

The results showed that at the tested concentrations, SiNPs could decrease HUVEC viability, but the deferoxamine mesylate (an iron ion chelator) might rescue this reduction of cell viability. Also, increased levels of intracellular reactive oxygen species and enhanced mRNA expression of lipid oxidation enzymes (ACSL4 and LPCAT3) with increase in lipid peroxidation (malondialdehyde), but decreased ratios of intracellular GSH/total-GSH and mitochondrial membrane potential as well as reduced enzymatic activities of anti-oxidative enzymes (CAT, SOD, and GSH-PX), were found in the SiNPs-treated HUVECs. Meanwhile, increase in p38 protein phosphorylation and decrease in NrF2 protein phosphorylation with reduced mRNA expressions of downstream anti-oxidative enzyme genes (CAT, SOD1, GSH-PX, and GPX4) was identified in the SiNPs-exposed HUVECs. These data indicated that SiNPs exposure might induce ferroptosis in HUVECs via p38 inhibiting NrF2 pathway. Ferroptosis of HUVECs will become a useful biomarker for assessing the cardiovascular health risks of environmental contaminants.

Perfluorooctane sulfonate promotes atherosclerosis by modulating M1 polarization of macrophages through the NF-κB pathway

Perfluorooctane sulfonate (PFOS) is a widely used and distributed perfluorinated compounds and is reported to be harmful to cardiovascular health; however, the direct association between PFOS exposure and atherosclerosis and the underlying mechanisms remain unknown. Therefore, this study aimed to investigate the effects of PFOS exposure on the atherosclerosis progression and the underlying mechanisms. PFOS was administered through oral gavage to apolipoprotein E-deficient (ApoE^-/-) mice for 12 weeks. PFOS exposure significantly increased pulse wave velocity (PWV) and intima-media thickness (IMT), increased aortic plaque burden and vulnerability, and elevated serum lipid and inflammatory cytokine levels. PFOS promoted aortic and RAW264.7 M1 macrophage polarization, which increased the secretion of nitric oxide synthase (iNOS) and pro-inflammatory factors (tumor necrosis factor-α [TNF-α], interleukin-6 [IL-6], and interleukin-1β [IL-1β]), and suppressed M2 macrophage polarization, which decreased the expression of CD206, arginine I (Arg-1), and interleukin-10 (IL-10). Moreover, PFOS activated nuclear factor-kappa B (NF-κB) in the aorta and macrophages. BAY11-7082 was used to inhibit NF-κB-alleviated M1 macrophage polarization and the inflammatory response induced by PFOS in RAW264.7 macrophages. Our results are the first to reveal the acceleratory effect of PFOS on the atherosclerosis progression in ApoE^-/- mice, which is associated with the NF-κB activation of macrophages to M1 polarization to induce inflammation.

Silica nanoparticles aggravated the metabolic associated fatty liver disease through disturbed amino acid and lipid metabolisms-mediated oxidative stress

The metabolic associated fatty liver disease (MAFLD) is a public health challenge, leading to a global increase in chronic liver disease. The respiratory exposure of silica nanoparticles (SiNPs) has revealed to induce hepatotoxicity. However, its role in the pathogenesis and progression of MAFLD was severely under-studied. In this context, the hepatic impacts of SiNPs were investigated in vivo and in vitro through using ApoE^-/- mice and free fatty acid (FFA)-treated L02 hepatocytes. Histopathological examinations and biochemical analysis showed SiNPs exposure via intratracheal instillation aggravated hepatic steatosis, lipid vacuolation, inflammatory infiltration and even collagen deposition in ApoE^-/- mice, companied with increased hepatic ALT, AST and LDH levels. The enhanced fatty acid synthesis and inhibited fatty acid β-oxidation and lipid efflux may account for the increased hepatic TC/TG by SiNPs. Consistently, SiNPs induced lipid deposition and elevated TC in FFA-treated L02 cells. Further, the activation of hepatic oxidative stress was detected in vivo and in vitro, as evidenced by ROS accumulation, elevated MDA, declined GSH/GSSG and down-regulated Nrf2 signaling. Endoplasmic reticulum (ER) stress was also triggered in response to SiNPs-induced lipid accumulation, as reflecting by the remarkable ER expansion and increased BIP expression. More importantly, an UPLC-MS-based metabolomics analysis revealed that SiNPs disturbed the hepatic metabolic profile in ApoE^-/- mice, prominently on amino acids and lipid metabolisms. In particular, the identified differential metabolites were strongly correlated to the activation of oxidative stress and ensuing hepatic TC/TG accumulation and liver injuries, contributing to the progression of liver diseases. Taken together, our study showed SiNPs promoted hepatic steatosis and liver damage, resulting in the aggravation of MAFLD progression. More importantly, the disturbed amino acids and lipid metabolisms-mediated oxidative stress was a key contributor to this phenomenon from a metabolic perspective.

The uses of transcriptomics and lipidomics indicated that direct contact with graphene oxide altered lipid homeostasis through ER stress in 3D human brain organoids

The potential uses of graphene-based nanomaterials (NMs) in various fields lead to the concern about their neurotoxicity, considering that graphene-based NMs are capable to cross blood brain barrier (BBB) and enter central nervous system (CNS). Although previous studies reported the possibility of graphene-based NM exposure to alter lipid homeostasis in animals or cultured neurons, recent studies suggested the need to use 3D human brain organoids for mechanism-based toxicological studies as this model might better recapitulate the complex human brains. Herein, we used multi-omics techniques to investigate the mechanisms of graphene oxide (GO) on lipid homeostasis in a novel 3D brain organoid model. We found that 50 μg/mL GO induced cytotoxicity but not superoxide. RNA-sequencing data showed that 50 μg/mL GO significantly up-regulated and down-regulated 80 and 121 genes, respectively. Furthermore, we found that GO exposure altered biological molecule metabolism pathways including lipid metabolism. Consistently, lipidomics data supported dose-dependent alteration of lipid profiles by GO in 3D brain organoids. Interestingly, co-exposure to GO and endoplasmic reticulum (ER) stress inhibitor 4-phenylbutyric acid (4-PBA) decreased most of the lipid classes compared with the exposure of GO only. We further verified that exposure to GO promoted ER stress marker GRP78 proteins, which in turn activated IRE1α/XBP-1 axis, and these changes were partially or completely inhibited by 4-PBA. These results proved that direct contact with GO disrupted lipid homeostasis through the activation of ER stress. As 3D brain organoids resemble human brains, these data might be better extrapolated to humans.

Fuzheng Nizeng Decoction regulated ferroptosis and endoplasmic reticulum stress in the treatment of gastric precancerous lesions: A mechanistic study based on metabolomics coupled with transcriptomics

Background: Fuzheng Nizeng Decoction (FZNZ) has a history of decades in gastric precancerous lesions (GPL) treatment, which has shown clear clinical efficacy. Blocking GPL is a key measure to reduce the incidence of gastric cancer (GC). Therefore, we aim to investigate the mechanism of FZNZ-induced ferroptosis and endoplasmic reticulum (ER) in MNNG-induced gastric precancerous lesion (MC) cells, which has been rarely studied in Traditional Chinese Medicine (TCM). Methods: First, CCK8 and lactate dehydrogenase assays were conducted to study the potential effect of FZNZ on MC cells. Second, combined transcriptomic and metabolomic analysis were used to explore the effect and mechanism of FZNZ. Functionally, the occurrence of ferroptosis was assessed by transmission electron microscopy morphological observation and measurement of ferrous iron levels, lipid peroxidation, and glutathione levels. Finally, the expression levels of mRNAs or proteins related to ferroptosis and ER stress were determined by qPCR or western blot assays, respectively. Results: FZNZ inhibited MC cells viability and induced cell death. By metabolomics coupled with transcriptomics analysis, we found that the mechanism of FZNZ treatment induced ferroptosis and was related to glutathione metabolism and ER stress. We then, for the first time, found that FZNZ induced ferroptosis, which contributed to an increase in intracellular ferrous iron, reactive oxygen species, and malondialdehyde and a decrease in glutathione. Meanwhile, the protein level of glutathione peroxidase 4 (GPX4) was decreased. The mRNA levels of ATF3/CHOP/CHAC1, which are related to ferroptosis and ER stress, were also upregulated. Conclusion: Our results elaborate that FZNZ could induce ferroptosis and ER stress in MC cells, and reduce GPX4/GSH. ATF3/CHOP/CHAC1 may play a crosstalk role, which provides a new molecular mechanism for the treatment of GPL.

Silica nanoparticles perturbed mitochondrial dynamics and induced myocardial apoptosis via PKA-DRP1-mitochondrial fission signaling

Silica nanoparticles (SiNPs) are among the most abundantly produced nanosized particles in the global market, and their potential toxicity has aroused a great concern. Increasing epidemiological investigations and experimental evidence revealed the threaten of SiNPs exposure to cardiovascular system. The myocardial toxicity caused by SiNPs was gradually demonstrated, nevertheless, the underlying mechanisms remain unclear. In view of mitochondria serving as the centrality in the prominent of cardiovascular disease, we investigated the role of mitochondria and related mechanisms in SiNPs-induced adverse effects on cardiomyocytes. As a result, SiNPs were found in cytoplasm, accompanied with morphological alterations in mitochondria, such as cristae fracture or disappearance, vacuolation. The induction of mitochondrial dysfunction by SiNPs was confirmed, as indicated by the excessive reactive oxygen species (ROS) formation, and blockage of cellular respiratory and ATP production. Concomitantly, SiNPs activated mitochondria-mediated apoptotic signaling in view of the up-regulated BAX, increased Caspase-9 cleavage and declined Bcl-2, ultimately resulting in myocardial apoptosis. It was noteworthy that SiNPs disturbed mitochondrial dynamics toward fission phenotype, which was supported by the dysregulated fission/fusion regulators. Especially, DRP1 and its phosphorylated level at s616 (p-DRP1^s616) were up-regulated, whilst its phosphorylated level at s637 (p-DRP1^s637) and PKA phosphorylation were down-regulated in SiNPs-treated cardiomyocytes in a dose-dependent manner. More importantly, the mechanistic investigations revealed PKA-DRP1-mediated mitochondrial fission was responsible for SiNPs-induced cardiomyocyte apoptosis through the mitochondria-mediated apoptotic way. This study firstly demonstrated the disturbance of mitochondrial dynamics played a crucial role in cardiomyocyte apoptosis caused by SiNPs, attributing to PKA-DRP1-mitochondrial fission signaling.

Silica nanoparticles induce cardiac injury and dysfunction via ROS/Ca2+/CaMKII signaling

Interest is growing to better comprehend the interaction of silica nanoparticles (SiNPs) with the cardiovascular system. In particular, the extremely small size, relatively large surface area and associated unique properties may greatly enhance its toxic potentials compared to larger-sized counterparts. Nevertheless, the underlying mechanisms still need to be evaluated. In this context, the cardiotoxicity of nano-scale (Si-60; particle diameter about 60 nm) and submicro-scale silica particles (Si-300; 300 nm) were examined in ApoE^-/- mice via intratracheal instillation, 6.0 mg/kg·bw, once per week for 12 times. The echocardiography showed that the sub-chronic exposure of Si-60 declined cardiac output (CO) and stroke volume (SV), shorten LVIDd and LVIDs, and thickened LVAWs of ApoE^-/- mice in compared to the control and Si-300 groups. Histological investigations manifested Si-60 enhanced inflammatory infiltration, myocardial fiber arrangement disorder, hypertrophy and fibrosis in the cardiac tissue, as well as mitochondrial ultrastructural injury. Accordingly, the serum cTnT, cTnI and ANP were significantly elevated by Si-60, as well as cardiac ANP content. In particular, Si-60 greatly increased cardiac ROS, Ca²⁺ levels and CaMKII activation in comparison with Si-300. Further, in vitro investigations revealed silica particles induced a dose- and size-dependent activation of oxidative stress, mitochondrial membrane permeabilization, intracellular Ca²⁺ overload, CaMKII signaling activation and ensuing myocardial apoptosis in human cardiomyocytes (AC16). Mechanistic analyses revealed SiNPs induced myocardial apoptosis via ROS/Ca²⁺/CaMKII signaling, which may contribute to the abnormalities in cardiac structure and function in vivo. In summary, our research revealed SiNPs caused myocardial impairments, dysfunction and even structural remodeling via ROS/Ca²⁺/CaMKII signaling. Of note, a size-dependent myocardial toxicity was noticed, that is, Si-60 greater than Si-300.

Toxicity mechanism of nanomaterials: Focus on endoplasmic reticulum stress

Over the years, although the broad application of nanomaterials has not brought convenience to people's life, growing concern surrounds their safety. Recently, much emphasis has been placed on exploring the toxicity mechanism of nanoparticles. Currently established toxic mechanisms include oxidative stress, inflammatory response, autophagy, and DNA damage. In recent years, endoplasmic reticulum stress (ERS) has gained widespread attention as another toxic mechanism of nanomaterials. It is widely acknowledged that the endoplasmic reticulum (ER) is an important site for protein synthesis, and lipids and Ca⁺ storage, playing an esseential role in the normal operation of the body functions. When the body's internal environment is damaged, the structure and function of the endoplasmic reticulum are destroyed, leading to a series of biological reactions called endoplasmic reticulum stress (ERS.) This paper reviews the mechanism of ERS in nanomaterial-associated toxicity. The process of ERS and its related unfolded protein response were briefly introduced, summarizing the factors affecting the nanoparticle ability to induce ERS and expounding on the changes of ER morphology after exposure to nanoparticles. Finally, the specific role and molecular mechanism of ERS under the action of different nanoparticles were comprehensively analyzed, including the relationship between ERS and inflammation, oxidative stress, lipid metabolism and apoptosis. This review provides a foothold for future studies on the toxic mechanism of nanoparticles, and provides novel insights into the safe application of nanoparticles and the treatment of diseases.

Long-term respiratory exposure to amorphous silica nanoparticles promoted systemic inflammation and progression of fibrosis in a susceptible mouse model

Exposure to amorphous silica nanoparticles (SiNPs) has increased dramatically, and concerns are growing about their potential health effects. However, their long-term systemic toxicity profile and underlying mechanisms following respiratory exposure still remains unexplored. It is well documented that the inhalation of ultrafine particles is firmly associated with adverse effects in humans. Environmental pollutants may contribute to diverse adverse effect or comorbidity in susceptible individuals. Thereby, we examined the long-term systemic effects of inhaled SiNPs using a sensitive mouse model (ApoE^-/-) fed by a western diet. Male ApoE^-/- mice were intratracheally instilled with SiNPs suspension at a dose of 1.5, 3.0 and 6.0 mg/kg·bw, respectively, once per week, 12 times in total. The histological analysis was conducted. The serum cytokine levels were quantified by RayBiotech antibody array. As a result, systemic histopathological alterations were noticed, mainly characterized by inflammation and fibrosis. More importantly, cytokine array analysis indicated the key role of mast cells accumulation in systemic inflammation and fibrosis progression induced by inhaled SiNPs. Collectively, our study firstly demonstrated that long-term exposure to inhaled SiNPs promoted the mast cell-dominated activation of inflammatory response, not only in the lung but also in heart, liver and kidney, etc., eventually leading to the progression of tissue fibrosis in ApoE^-/- mice.

Amorphous silica nanoparticles caused lung injury through the induction of epithelial apoptosis via ROS/Ca2+/DRP1-mediated mitochondrial fission signaling

The adverse effects of amorphous silica nanoparticles (SiNPs) exposure on the respiratory system were increasingly recognized, however, its potential pathogenesis still remains not fully elucidated. So, this study aimed to explore its effects on pulmonary injury, and to investigate related mechanisms. Histological investigations illustrated SiNPs triggered the lung injury, mainly manifested as alveolar structure destruction, collagen deposition, and mitochondrial ultrastructural injury. In particular, SiNPs greatly enhanced pulmonary ROS and TUNEL positive rate in lungs, both of which were positively correlated with lung impairments. Further, the underlying mechanisms were investigated in cultured human bronchial epithelial cells (16HBE). Consistent with the in vivo findings, SiNPs caused the impairments on mitochondrial structure, as well as the activation of ROS generation and oxidative injury. Upon SiNPs stimuli, mitochondrial respiration was greatly inhibited, while Ca2+ overload in cytosol and mitochondria owing to ER calcium release was noticed, resulting in mitochondrial-dependent epithelial apoptosis. More importantly, mitochondrial dynamics was imbalanced toward a fission type, as evidenced by upregulated DRP1 and its phosphorylation at Ser616 (DRP1s616), while downregulated DRP1s637, and also MFN1, MFN2. Mechanistic investigations revealed that the activation of ROS/Ca2+ signaling promoted DRP1-mediated mitochondrial fission by SiNPs, forming a vicious cycle, and ultimately contributing to apoptosis in 16HBE. In summary, our results disclosed SiNPs caused pulmonary injury through the induction of epithelial apoptosis via a ROS/Ca2+/DRP1-mediated mitochondrial fission axis.

Silica nanoparticles: Biomedical applications and toxicity

Silica nanoparticles (SiNPs) are composed of silicon dioxide, the most abundant compound on Earth, and are used widely in many applications including the food industry, synthetic processes, medical diagnosis, and drug delivery due to their controllable particle size, large surface area, and great biocompatibility. Building on basic synthetic methods, convenient and economical strategies have been developed for the synthesis of SiNPs. Numerous studies have assessed the biomedical applications of SiNPs, including the surface and structural modification of SiNPs to target various cancers and diagnose diseases. However, studies on the in vitro and in vivo toxicity of SiNPs remain in the exploratory stage, and the toxicity mechanisms of SiNPs are poorly understood. This review covers recent studies on the biomedical applications of SiNPs, including their uses in drug delivery systems to diagnose and treat various diseases in the human body. SiNP toxicity is discussed in terms of the different systems of the human body and the individual organs in those systems. This comprehensive review includes both fundamental discoveries and exploratory progress in SiNP research that may lead to practical developments in the future.

Lysosomal impairment-mediated autophagy dysfunction responsible for the vascular endothelial apoptosis caused by silica nanoparticle via ROS/PARP1/AIF signaling pathway

Understanding the underlying interactions of nanoparticles (NPs) with cells is crucial to the nanotoxicological research. Evidences suggested lysosomes as a vital target upon the accumulation of internalized NPs, and lysosomal damage and autophagy dysfunction are emerging molecular mechanisms for NPs-elicited toxicity. Nevertheless, the interaction with lysosomes, ensuing adverse effects and the underlying mechanisms are still largely obscure, especially in NPs-induced vascular toxicity. In this study, silica nanoparticles (SiNPs) were utilized to explore the adverse effects on lysosome in vascular endothelial cells by using in vitro cultured human endothelial cells (HUVECs), and in-depth investigated the mechanisms involved. Consequently, the internalized SiNPs accumulated explicitly in the lysosomes, and caused lysosomal dysfunction, which were prominent on the increased lysosomal membrane permeability, decline in lysosomal quantity, destruction of acidic environment of lysosome, and also disruption of lysosomal enzymes activities, resulting in autophagy flux blockage and autophagy dysfunction. More importantly, mechanistic results revealed the SiNPs-caused lysosomal impairments and resultant autophagy dysfunction could promote oxidative stress, DNA damage and the eventual cell apoptosis activated by ROS/PARP1/AIF signaling pathway. These findings improved the understanding of SiNPs-induced vascular injury, and may provide novel information and warnings for SiNPs applications in the fields of nanomedicine.

Nutrient molecule corona: An update for nanomaterial-food component interactions

The adsorption of biological molecules to nanomaterials (NMs) will significantly impact NMs' behavior in complex microenvironments. Previously we proposed the need to consider the interactions between food components and NMs for the evaluation of oral toxicity of NMs. This review updated this concept as nutrient molecule corona, that the adsorption of nutrient molecules alters the uptake of nutrient molecules and/or NMs, as well as the signaling pathways to induce a combined toxicity due to the biologically active nature of nutrient molecules. Even with the presence of protein corona, nutrient molecules may still bind to NMs to change the identities of NMs in vivo. Furthermore, this review proposed the binding of excessive nutrient molecules to NMs to induce a combined toxicity under pathological conditions such as metabolic diseases. The structures of nutrient molecules and physicochemical properties of NMs determine nutrient molecule corona formation, and these aspects should be considered to limit the unwanted effects brought by nutrient molecule corona. In conclusion, similar to other biological molecule corona, the formation of nutrient molecule corona due to the presence of food components or excessive nutrient molecules in pathophysiological microenvironments will alter the behaviors of NMs.

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

Nanoparticles (NPs) can make their way to the brain and cause in situ damage, which is a concern for nanomaterial application and airborne particulate matter exposure. Our recent study indicated that respiratory exposure to silica nanoparticles (SiO₂ NPs) caused unexpected cardiovascular toxic effects. However, the toxicities of SiO₂ NPs in other organs have warranted further investigation. To confirm the accumulation of SiO₂ NPs in the brain, we introduced SiO₂ NPs with different diameters into mice via intranasal instillation (INI) and intravenous injection (IVI) in parallel. We found that SiO₂ NPs may target the brain through both olfactory and systemic routes, but the size of SiO₂ NPs and delivery routes both significantly affected their brain accumulation. Surprisingly, while equivalent SiO₂ NPs were found in the brain regions, brain lesions were distinctly much higher in INI than in the IVI group. Mechanistically, we showed that SiO₂ NPs introduced via INI induced brain apoptosis and autophagy, while the SiO₂ NPs introduced via IVI only induced autophagy in the brain.

Myocardial toxicity induced by silica nanoparticles in a transcriptome profile

The deleterious effects of silica nanoparticles (SiNPs) on human health and the ecological system have gradually gained attention owing to their heavy annual output and extensive global flux. The updated epidemiological or experimental investigations have demonstrated the potential myocardial toxicity triggered by SiNPs, but the underlying mechanisms and long-lasting cardiac effects are still poorly understood. Here, a rat model of sub-chronic respiratory exposure to SiNPs was conducted, and the histopathological analysis and ultrastructural investigation of heart tissues were carried out. More importantly, a comprehensive analysis of whole-genome transcription was utilized in rat heart to uncover key biological and cellular mechanisms triggered by SiNPs. The widening of myocardial space and partial fiber rupture were clearly manifested in rat heart after prolonged SiNPs exposure, particularly accompanied by mitochondrial swelling and cristae rupture. With the aid of Affymetrix GeneChips, 3153 differentially expressed genes (DEGs) were identified after SiNPs exposure, including 1916 down- and 1237 up-regulated genes. GO and KEGG analysis illustrated many important biological processes and pathways perturbed by SiNPs, mainly specializing in cellular stress, energy metabolism, actin filament dynamics and immune response. Signal-net analysis revealed that Prkaca (PKA) plays a core role in the cardiac toxification process of prolonged exposure of SiNPs to rats. Furthermore, qRT-PCR verified that PKA-mediated calcium signaling is probably responsible for SiNPs-induced cardiac injury. Conclusively, our study revealed that SiNPs caused myocardial injury, and particularly, provided transcriptomic insight into the role of PKA-calcium signaling triggered by SiNPs, which would facilitate SiNPs-based nanosafety assessment and biomedicine development.

PINK1/TAX1BP1-directed mitophagy attenuates vascular endothelial injury induced by copper oxide nanoparticles

Copper oxide nanoparticles (CuONPs) are widely used metal oxide NPs owing to their excellent physical–chemical properties. Circulation translocation of CuONPs after inhalation leads to vascular endothelial injury. Mitochondria, an important regulatory hub for maintaining cell functions, are signaling organelles in responses to NPs-induced injury. However, how mitochondrial dynamics (fission and fusion) and mitophagy (an autophagy process to degrade damaged mitochondria) are elaborately orchestrated to maintain mitochondrial homeostasis in CuONPs-induced vascular endothelial injury is still unclear. In this study, we demonstrated that CuONPs exposure disturbed mitochondrial dynamics through oxidative stress-dependent manner in vascular endothelial cells, as evidenced by the increase of mitochondrial fission and the accumulation of fragmented mitochondria. Inhibition of mitochondrial fission with Mdivi-1 aggravated CuONPs-induced mtROS production and cell death. Furthermore, we found that mitochondrial fission led to the activation of PINK1-mediated mitophagy, and pharmacological inhibition with wortmannin, chloroquine or genetical inhibition with siRNA-mediated knockdown of PINK1 profoundly repressed mitophagy, suggesting that the protective role of mitochondrial fission and PINK1-mediated mitophagy in CuONPs-induced toxicity. Intriguingly, we identified that TAX1BP1 was the primary receptor to link the ubiquitinated mitochondria with autophagosomes, since TAX1BP1 knockdown elevated mtROS production, decreased mitochondrial clearance and aggravated CuONPs-induced cells death. More importantly, we verified that urolithin A, a mitophagy activator, promoted mtROS clearance and the removal of damaged mitochondria induced by CuONPs exposure both in vitro and in vivo. Overall, our findings indicated that modulating mitophagy may be a therapeutic strategy for pathological vascular endothelial injury caused by NPs exposure.

CuONPs disturb mitochondrial dynamics and trigger mitophagy in vascular endothelial cells and mouse blood vessel.

PINK1/TAX1BP1-mediated mitophagy regulates the removal of excessive ROS and aberrant mitochondria in CuONPs-treated vascular endothelial cells.

The mitophagy activator urolithin A attenuates CuONPs-induced vascular endothelial cells death and mice vascular injury.

Melatonin alleviates PM2.5-triggered macrophage M1 polarization and atherosclerosis via regulating NOX2-mediated oxidative stress homeostasis

It is reported that oxidative stress homeostasis was involved in PM_2.5-induced foam cell formation and progression of atherosclerosis, but the exact molecular mechanism is still unclear. Melatonin is an effective antioxidant that could reverse the cardiopulmonary injury. The main purpose of this study is to investigate the latent mechanism of PM_2.5-triggered atherosclerosis development and the protective role of melatonin administration. Vascular Doppler ultrasound showed that PM_2.5 exposure reduced aortic elasticity in ApoE^-/- mice. Meanwhile, blood biochemical and pathological analysis demonstrated that PM_2.5 exposure caused dyslipidemia, elicited oxidative damage of aorta and was accompanied by an increase in atherosclerotic plaque area; while the melatonin administration could effectively alleviate PM_2.5-induced macrophage M1 polarization and atherosclerosis in mice. Further investigation verified that NADPH oxidase 2 (NOX2) and mitochondria are two prominent sources of PM_2.5-induced ROS production in vascular macrophages. Whereas, the combined use of two ROS-specific inhibitors and adopted with melatonin markedly rescued PM_2.5-triggered macrophage M1 polarization and foam cell formation by inhibiting NOX2-mediated crosstalk of Keap1/Nrf2/NF-κB and TLR4/TRAF6/NF-κB signaling pathways. Our results demonstrated that NOX2-mediated oxidative stress homeostasis is critical for PM_2.5-induced atherosclerosis and melatonin might be a potential treatment for air pollution-related cardiovascular diseases.

Silica nanoparticles induce pyroptosis and cardiac hypertrophy via ROS/NLRP3/Caspase-1 pathway

Growing literatures suggest that silica nanoparticles (SiNPs) exposure is correlated with adverse cardiovascular effects. Cardiac hypertrophy is one of the most common risk factors for heart failure. However, whether SiNPs involved in cardiac hypertrophy and the underlying mechanisms was remained unexploited. Our study aimed to investigate the molecular mechanisms of SiNPs on pyroptosis and cardiac hypertrophy. The in vivo results found that SiNPs induced ultrastructural change and histopathological damage, accompanied by oxidative damage occurred and increased levels of inflammatory factors (IL-18 and IL-1β) in heart tissue. In addition, SiNPs could upregulate the expressions of cardiac hypertrophy-related special marker including ANP, BNP, β-MHC, it also elevated the pyroptosis-related protein, such as NLRP3, Cleaved-Caspase-1, GSDMD, IL-18 and Cleaved-IL-1β in vivo. For in vitro study, SiNPs increased the intracellular ROS generation and activated the NLRP3/Caspase-1/GSDMD signaling pathway in cardiomyocytes. Whereas, the NADPH oxidase (NOX) inhibitor VAS2870 had effectively inhibited the ROS level and suppressed the expression of NLRP3, ASC, Pro-Caspase-1, Cleaved-Caspase-1, N-GSDMD, IL-18, Cleaved-IL-1β, ANP, BNP and β-MHC. Moreover, transfected with si-NLRP3 or adopted with Caspase-1 inhibitor VX-765 in cardiomyocytes showed an inhibitory effect on SiNPs-induced pyroptosis and cardiac hypertrophy. In summary, our results demonstrated that SiNPs could trigger pyroptosis and cardiac hypertrophy via ROS/NLRP3/Caspase-1 signaling pathway.

TiO2 nanosheets promote the transformation of vascular smooth muscle cells into foam cells in vitro and in vivo through the up-regulation of nuclear factor kappa B subunit 2

Titanium dioxide (TiO₂) nanomaterials have been shown to promote atherosclerosis through endothelial dysfunction. This study investigated the toxicity of TiO₂ nanosheets (NSs) to vascular smooth muscle cells (VSMCs), one of the pivotal cells involved in all stages of atherosclerosis. Only a high concentration of TiO₂ NSs (128 μg/mL) modestly induced cytotoxicity by decreasing thiols. RNA-sequencing data revealed that 64 μg/mL TiO₂ NSs significantly down-regulated 94 genes and up-regulated 174 genes, respectively. Gene ontology (GO) terms and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways related to SMC function and lipid metabolism were altered. TiO₂ NSs increased nuclear factor kappa B subunit 2 (NFKB2), which led to a decrease in VSMC marker actin alpha 2, smooth muscle (ACTA2). On the other hand, macrophage marker CD36 and fatty acid synthase (FASN) proteins were increased. Additionally, TiO₂ NSs induced inflammatory cytokines and lipid accumulation, and these effects were curtailed by NFKB inhibitor - triptolide. Furthermore, repeated TiO₂ NS injection (5 mg/kg BW, once a day for 5 continuous days) into ICR mice led to increased NFKB2, CD36 and FASN, with a decreased ACTA2. Our results suggested that TiO₂ NSs promoted the transformation of VSMCs into foam cells through the up-regulation of NFKB2.

Inhaled silica nanoparticles exacerbate atherosclerosis through skewing macrophage polarization towards M1 phenotype

BACKGROUND AND AIMS

Exposure to environmental nanoparticles is related to the adverse impact on health, including cardiovascular system. Various forms of nanoparticles have been reported to interact with endothelium and induce inflammation. However, the potential role of nanoparticles in the pathogenesis of atherosclerosis and their mechanisms of action are still unclear. The aim of this study was to investigate the effect of two broadly used nanomaterials, which also occur in natural environment - silicon oxide (SiO2) and ferric oxide (Fe2O3) in the form of nanoparticles (NPs) - on the development of atherosclerosis.

METHODS

We used apolipoprotein E-knockout mice exposed to silica and ferric oxide nanoparticles in a whole body inhalation chamber.

RESULTS

Inhaled silica nanoparticles augmented the atherosclerotic lesions and increased the percentage of pro-inflammatory M1 macrophages in both the plaque and the peritoneum in apoE-/- mice. Exposure to ferric oxide nanoparticles did not enhance atherogenesis process, however, it caused significant changes in the atherosclerotic plaque composition (elevated content of CD68-positive macrophages and enlarged necrotic core accompanied by the decreased level of M1 macrophages). Both silica and ferric oxide NPs altered the phenotype of T lymphocytes in the spleen by promoting polarization towards Th17 cells.

CONCLUSIONS

Exposure to silica and ferric oxide nanoparticles exerts impact on atherosclerosis development and plaque composition. Pro-atherogenic abilities of silica nanoparticles are associated with activation of pro-inflammatory macrophages.

Macrophage-targeted nanomedicine for the diagnosis and treatment of atherosclerosis

Nanotechnology could improve our understanding of the pathophysiology of atherosclerosis and contribute to the development of novel diagnostic and therapeutic strategies to further reduce the risk of cardiovascular disease. Macrophages have key roles in atherosclerosis progression and, therefore, macrophage-associated pathological processes are important targets for both diagnostic imaging and novel therapies for atherosclerosis. In this Review, we highlight efforts in the past two decades to develop imaging techniques and to therapeutically manipulate macrophages in atherosclerotic plaques with the use of rationally designed nanoparticles. We review the latest progress in nanoparticle-based imaging modalities that can specifically target macrophages. Using novel molecular imaging technology, these modalities enable the identification of advanced atherosclerotic plaques and the assessment of the therapeutic efficacy of medical interventions. Additionally, we provide novel perspectives on how macrophage-targeting nanoparticles can deliver a broad range of therapeutic payloads to atherosclerotic lesions. These nanoparticles can suppress pro-atherogenic macrophage processes, leading to improved resolution of inflammation and stabilization of plaques. Finally, we propose future opportunities for novel diagnostic and therapeutic strategies and provide solutions to challenges in this area for the purpose of accelerating the clinical translation of nanomedicine for the treatment of atherosclerotic vascular disease.

Influences of Unmodified and Carboxylated Carbon Nanotubes on Lipid Profiles in THP-1 Macrophages: A Lipidomics Study

Since the possible roles of surface modifications in determining multi-walled carbon nanotube (MWCNT)-promoted endoplasmic reticulum (ER) stress-mediated lipid-laden macrophage foam cell formation are still in debate, we compared unmodified and carboxylated MWCNT-induced cytotoxicity, lipid profile changes, and expression of ER stress genes in THP-1 macrophages. Particularly, we focused on lipid profile changes by using lipidomics approaches. We found that unmodified and carboxylated MWCNTs significantly decreased cellular viability and appeared to damage the cellular membrane to a similar extent. Likewise, the results from Oil Red O staining showed that both types of MWCNTs slightly but significantly induced lipid accumulation. In keeping with Oil Red O staining results, lipidomics data showed that both types of MWCNTs up-regulated most of the lipid classes. Interestingly, almost all lipid classes were relatively higher in carboxylated MWCNT-exposed THP-1 macrophages compared with unmodified MWCNT-exposed cells, indicating that carboxylated MWCNTs more effectively changed lipid profiles. But in contrast to our expectation, none of the MWCNTs significantly induced the expression of ER stress genes. Even, compared with carboxylated MWCNTs, unmodified MWCNTs induced higher expression of lipid genes, including macrophage scavenger receptor 1 and fatty acid synthase. Combined, our results suggested that even though carboxylation did not significantly affect MWCNT-induced lipid accumulation, carboxylated MWCNTs were more potent to alter lipid profiles in THP-1 macrophages, indicating the need to use omics techniques to understand the exact nanotoxicological effects of MWCNTs. However, the differential effects of unmodified and carboxylated MWCNTs on lipid profiles might not be related with the induction of ER stress.

Nanoparticles and trained immunity: Glimpse into the future

Emerging evidences show that innate immune cells can display changes in their functional programs after infection or vaccination, which lead to immunomodulation (increased or reduced responsiveness) upon secondary activation to the same stimuli or even to a different one. Innate cells acquire features of immunological memory, nowadays using the new term of "trained immunity" or "innate immune memory", which is different from the specific memory immune response elicited by B and T lymphocytes. The review focused on the concept of trained immunity, mostly on myeloid cells. Special attention is dedicated to the pathogen recognition along the evolution (bacteria, plants, invertebrate and vertebrate animals), and to techniques used to study epigenetic reprogramming and metabolic rewiring. Nanomaterials can be recognized by immune cells offering a very promising way to learn about trained immunity. Nanomaterials could be modified in order to immunomodulate the responses ad hoc. Many therapeutic possibilities are opened, and they should be explored.

Oxidative stress- and mitochondrial dysfunction-mediated cytotoxicity by silica nanoparticle in lung epithelial cells from metabolomic perspective

Quantities of researches have demonstrated silica nanoparticles (SiNPs) exposure inevitably induced damage to respiratory system, nonetheless, knowledge of its toxicological behavior and metabolic interactions with the cellular machinery that determines the potentially deleterious outcomes are limited and poorly elucidated. Here, the metabolic responses of lung bronchial epithelial cells (BEAS-2B) under SiNPs exposure were investigated using ultra performance liquid chromatography-mass spectrum (UPLC-MS)-based metabolomics research. Results revealed that even with low cytotoxicity, SiNPs disturbed global metabolism. Five metabolic pathways were significantly perturbed, in particular, oxidative stress- and mitochondrial dysfunction-related GSH metabolism and pantothenate and coenzyme A (CoA) biosynthesis, where the identified metabolites glutathione (GSH), glycine, beta-alanine, cysteine, cysteinyl-glycine and pantothenic acid were included. In support of the metabolomics profiling, SiNPs caused abnormality in mitochondrial structure and mitochondrial dysfunction, as evidenced by the inhibition of cellular respiration and ATP production. Moreover, SiNPs triggered oxidative stress as confirmed by the dose-dependent ROS generation, down-regulated nuclear factor erythroid 2-related factor 2 (NRF2) signaling, together with GSH depletion in SiNPs-treated BEAS-2B cells. Oxidative DNA damage and cell membrane dis-integrity were also detected in response to SiNPs exposure, which was correspondingly in agreed with the elevated 8-hydroxyguanosine (8-OHdG) and decreased phospholipids screened through metabolic analysis. Thereby, we successfully used the metabolomics approaches to manifest SiNPs-elicited toxicity through oxidative stress, mitochondrial dysfunction, DNA damage and rupture of membrane integrity in BEAS-2B cells. Overall, our study provided novel insights into the mechanism underlying SiNPs-induced pulmonary toxicity.

Comparison of multi-walled carbon nanotubes and halloysite nanotubes on lipid profiles in human umbilical vein endothelial cells

Tubular nanomaterials (NMs), such as multi-walled carbon nanotubes (MWCNTs) and halloysite nanotubes (HNTs), may be used in biomedicine, but previous studies showed that MWCNTs induced toxicity to endothelial cells (ECs). However, the influence of tubular NMs on EC lipid profiles has gained little attention, probably because ECs are not traditionally considered to be involved in regulating lipid homeostasis. This study compared the different effects of MWCNTs and HNTs on lipid profile changes in human umbilical vein ECs (HUVECs). The results showed that MWCNTs but not HNTs of the same mass concentrations induced cytotoxicity, ultrastuctural changes and intracellular thiol depletion. Meanwhile, only MWCNTs promoted lipid accumulation due to the induction of ER stress leading to up-regulation of fatty acid synthase (FASN). Interestingly, lipidomics results showed that the main lipid classes induced by MWCNTs but not HNTs were ceramide (Cer) and phosphatidylinositol (PI), with most of the lipid classes unaltered or even decreased after NM exposure. Then, extra Cer and PI were added to explore the implications of increase of these lipids. Adding Cer promoted the cytotoxicity of MWCNTs to HUVECs, indicating the lipotoxic role of Cer. Whereas adding PI partially increased intracellular NO and decreased interleukin-6 (IL-6) release due to MWCNT exposure, indicating the signaling role of PI. These results indicated novel roles of lipid dysfunction in NM-induced toxicity to ECs, even though ECs are not the professional cells for controlling lipid homeostasis.

Potential roles of Kruppel-like factors in mediating adverse vascular effects of nanomaterials: A review

The development of nanotechnology leads to the exposure of human beings to nanomaterials (NMs), and there is a health concern about the adverse vascular effects of NMs. Current data from epidemiology, controlled human exposure, and animal studies suggested that exposure to NMs could induce cardiopulmonary effects. In support of in vivo findings, in vitro studies showed that direct contact of vascular cells with NMs could induce endothelial cell (EC) activation and promote macrophage foam cell formation, although only limited studies showed that NMs could damage vascular smooth muscle cells and promote their phenotypic switch. It has been proposed that NMs induced adverse vascular effects via different mechanisms, but it is still necessary to understand the upstream events. Kruppel-like factors (KLFs) are a set of C2H2 zinc finger transcription factors (TFs) that can regulate various aspects of vascular biology, but currently, the roles of KLF2 in mediating the adverse vascular effects of NMs have gained little attention by toxicologists. This review summarized current knowledge about the adverse vascular effects of NMs and proposed the potential roles of KLFs in mediating these effects based on available data from toxicological studies as well as the current understanding about KLFs in vascular biology. Finally, the challenges in investigating the role of KLFs in vascular toxicology were also summarized. Considering the important roles of KLFs in vascular biology, further studies are needed to understand the influence of NMs on KLFs and the downstream events.

Adverse effects of amorphous silica nanoparticles: Focus on human cardiovascular health

Amorphous silica nanoparticle (SiNPs) has tremendous potential for a host of applications, while its mass production, broad application and environmental release inevitably increase the risk of human exposure. SiNPs could enter into the human body through different routes such as inhalation, ingestion, skin contact and even injection for medical applications. The cardiovascular system is gradually recognized as one of the primary sites for engineered NPs exerting adverse effects. Accumulating epidemiological or experimental evidence support the association between SiNPs exposure and adverse cardiovascular effects. However, this topic is still in its infancy, and the literature shows high inter-study variability and even contradictory results. New challenges still present in the safety evaluation of SiNPs, and its toxicological mechanisms are poorly understood. Here, scientific papers related to cardiovascular studies of SiNPs in vivo and in vitro were selected, and the updated particle-caused cardiovascular toxicity and potential mechanisms were summarized. Moreover, the understanding of how factors primarily including exposure dose, route of administration, particle size and surface properties, influence the interaction between SiNPs and cardiovascular system was discussed. In particular, the adverse outcome pathway (AOP) framework by which SiNPs cause deleterious effects in the cardiovascular system was described, aiming to provide useful information necessary for the regulatory decision and to guide a safer application of nanotechnology.