Toxicity mechanism of engineered nanomaterials: Focus on mitochondria

Zinc oxide nanoparticles promote migrasomes formation

The rising pollution from zinc oxide nanoparticles (ZnO-NPs) poses significant global concerns due to their widespread environmental presence and potential negative effects on human health. This study explores how ZnO-NPs impact migrasomes formation, a crucial process for cellular migration and communication. Our findings indicate that 28 nm ZnO-NPs enhance migrasomes formation, correlating with increased levels of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and GTP-RhoA-essential molecules in migrasomes biogenesis. Additionally, ZnO-NPs help alleviate mitochondrial damage caused by carbonyl cyanide 3-chlorophenylhydrazone (CCCP) through mitocytosis, which removes dysfunctional mitochondria, thereby preserving cellular integrity. The migrasomes induced by ZnO-NPs were found to contain various cellular components, including mitochondria, lysosomes, lipid droplets, and the ZnO-NPs themselves. These results underscore the role of ZnO-NPs in promoting migrasomes formation and protecting mitochondrial function, revealing significant implications for cellular behavior, therapeutic applications, and environmental and health safety.

Adverse Outcome Pathway-Based Strategies to Mitigate Ag2Se Quantum Dot-Induced Neurotoxicity

Silver selenide quantum dots (Ag2Se QDs) show great advantages in tumor imaging due to their excellent optical performance and good biocompatibility. However, the ultrasmall particle size of Ag2Se QDs allows them to cross the blood-brain barrier, thus potentially affecting the central nervous system. Therefore, risk assessment and response strategies for Ag2Se QDs are important. The adverse outcome pathway (AOP) framework makes it possible to develop risk management strategies based on toxicity mechanisms. In this study, using the AOP framework, we constructed causal mechanism relationship diagrams at different biological levels of Ag2Se QD neurotoxicity. In this framework, excess mitochondrial reactive oxygen species (mtROS) triggered Nod-like receptor protein 3 (NLRP3) inflammasome activation in microglia was molecular initiation event (MIE). Proinflammatory mediator secretion and microglia activation were key events (KEs) at the cellular level. Neuroinflammation and neuronal damage were KEs at the organ/tissue level. Altered hippocampal physiology was the adverse outcome (AO) at the individual level. Based on the established AOP framework, further studies confirmed that mtROS-activated nuclear-factor-E2-related factor 2 (Nrf2)/PTEN-induced kinase 1 (PINK1)- mitophagy contributed to weaken the MIE. Molecular docking-assisted molecular biology experiments demonstrated that quercetin (Qu) enhanced this process. This article emphasizes the importance of the AOP in the risk management of nanomaterials. Furthermore, this paper guides the use of natural small-molecule drugs as a strategy to mitigate nanomaterial-induced neurotoxicity.

Toxic effects and mechanistic insights of cadmium telluride quantum dots on the homeostasis and regeneration in planarians

The widespread application of quantum dots (QDs) in recent years has raised concerns about potential environmental and human health risks. Although the toxicity of cadmium telluride quantum dots (CdTe QDs) has been partially studied, their effects on stem cells, tissue regeneration, neurodevelopment, and neurobehavioral toxicity remain unclear. This study aimed to investigate the combined toxic effects and mechanisms of CdTe QDs on planarians at the individual, tissue, cellular, and molecular levels. The results showed that exposure to CdTe QDs led to tissue damage, abnormal motor behavior, delayed regeneration, morphological abnormalities, and reduced survival. Furthermore, CdTe QDs caused excessive stem cell proliferation, leading to defective differentiation of tissues such as the epidermis, cilia, protonephridia, muscle, and nerves. Neurotoxicity manifests as a reduction in the number of neurons and neurotransmitter imbalance. Further studies revealed that CdTe QDs induced cell death by promoting reactive oxygen species (ROS) accumulation, triggering oxidative stress and deoxyribonucleic acid (DNA) damage, which led to excessive mitochondrial fission and activation of the mitochondria-dependent apoptotic signaling pathway. Overall, the balance between stem cell proliferation, differentiation, and apoptosis was disrupted, ultimately leading to delayed regeneration and homeostatic imbalance. These findings offer new insights into the environmental risk assessment of QDs and provide valuable directions for further research on their toxic effects on human stem cells and regenerative processes.

Navigating Neurotoxicity and Safety Assessment of Nanocarriers for Brain Delivery: Strategies and Insights

Nanomedicine, an area that uses nanomaterials for theragnostic purposes, is advancing rapidly, particularly in the detection and treatment of neurodegenerative diseases. The design of nanocarriers can be optimized to enhance drug bioavailability and targeting to specific organs, improving therapeutic outcomes. However, clinical translation hinges on biocompatibility and safety. Nanocarriers can cross the blood-brain barrier (BBB), potentially causing neurotoxic effects through mechanisms such as oxidative stress, DNA damage, and neuroinflammation. Concerns about their accumulation and persistence in the brain make it imperative to carry out a nanotoxicological risk assessment. Generally, this involves identifying exposure sources and routes, characterizing physicochemical properties, and conducting cytotoxicity assays both in vitro and in vivo. The lack of a specialized regulatory framework creates substantial gaps, making it challenging to translate findings across development stages. Additionally, there is a pressing need for innovative testing methods due to constraints on animal use and the demand for high-throughput screening. This review examines the mechanisms of nanocarrier-induced neurotoxicity and the challenges in risk assessment, highlighting the impact of physicochemical properties and the advantages and limitations of current neurotoxicity evaluation models. Future perspectives are also discussed. Additional guidance is crucial to improve the safety of nanomaterials and reduce associated uncertainty. STATEMENT OF SIGNIFICANCE: Nanocarriers show tremendous potential for theragnostic purposes in neurological diseases, enhancing drug targeting to the brain, and improving biodistribution and pharmacokinetics. However, their neurotoxicity is still a major field to be explored, with only 5% of nanotechnology-related publications addressing this matter. This review focuses on the issue of neurotoxicity and safety assessment of nanocarriers for brain delivery. Neurotoxicity-relevant exposure sources, routes, and molecular mechanisms, along with the impact of the physicochemical properties of nanomaterials, are comprehensively described. Moreover, the different experimental models used for neurotoxicity evaluation are explored at length, including their main advantages and limitations. To conclude, we discuss current challenges and future perspectives for a better understanding of risk assessment of nanocarriers for neurobiomedical applications.

Taurine Protects against Silica Nanoparticle-Induced Apoptosis and Inflammatory Response via Inhibition of Oxidative Stress in Porcine Ovarian Granulosa Cells

Silica nanoparticles (SNPs) induce reproductive toxicity through ROS production, which significantly limits their application. The protective effects of taurine (Tau) against SNP-induced reproductive toxicity remain unexplored. So this study aims to investigate the impact of Tau on SNP-induced porcine ovarian granulosa cell toxicity. In vitro, granulosa cells were exposed to SNPs combined with Tau. The localization of SNPs was determined by TEM. Cell viability was examined by CCK-8 assay. ROS levels were measured by CLSM and FCM. SOD and CAT levels were evaluated using ELISA and qPCR. Cell apoptosis was detected by FCM, and pro-inflammatory cytokine transcription levels were measured by qPCR. The results showed that SNPs significantly decreased cell viability, while increased cell apoptosis and ROS levels. Moreover, SOD and CAT were decreased, while IFN-α, IFN-β, IL-1β, and IL-6 were increased after SNP exposures. Tau significantly decreased intracellular ROS, while it increased SOD and CAT compared to SNPs alone. Additionally, Tau exhibited anti-inflammatory effects and inhibited cell apoptosis. On the whole, these findings suggest that Tau mitigates SNP-induced cytotoxicity by reducing oxidative stress, inflammatory response, and cell apoptosis. Tau may be an effective strategy to alleviate SNP-induced toxicity and holds promising application prospects in the animal husbandry and veterinary industry.

Ball milling nano-sized biochar: bibliometrics, preparation, and environmental application

Nano-sized biochar, which is a small structure prepared from biochar by grinding, has surpassed traditional biochar in performance, showing enhanced effects and potential for a wide range of environmental applications. Firstly, this paper visualizes and analyzes the literature in this field by CiteSpace to clarify the development trend of nano-sized biochar. The review intuitively shows the most influential countries, the most productive institutions, and the most concerned hot spots in the field of nano-sized biochar. Secondly, these hotspots in environment management are summarized by keywords and clustering: (1) The application of ball milling is a modification scheme that researchers have paid attention to, and it is also a key method for preparing biochar nanomaterials. It has a more dispersed structure and can support more modified materials. (2) Nano-sized biochar in the comprehensive utilization of water, soil, and plants was discussed and is a small range of application modification methods. (3) The bidirectional effects of nano-sized biochar on plants were analyzed, and the challenges in its application were listed. Finally, the economic management of nano-sized biochar and the relationship between microorganisms are the focus of the next research.

Impact of polystyrene nanoplastics on apoptosis and inflammation in zebrafish larvae: Insights from reactive oxygen species perspective

In recent years, there has been a growing focus on the toxicity and mortality induced by nanoplastics (NPs) in aquatic organisms. However, studies investigating mechanisms underlying oxidative stress (OS), apoptosis, and inflammation induced by NPs in fish remain limited. This study observed that polystyrene NPs (PS-NPs) were accumulated into zebrafish larvae and zebrafish embryonic fibroblast (ZF4 cells), accompanied by the occurrence of pathological damage both at the cellular and tissue-organ level. Additionally, the transcriptional up-regulation of NADPH oxidases (NOXs) and subsequent excessive generation of reactive oxygen species (ROS) resulted in notable changes in the relative mRNA and protein expression levels associated with antioxidant oxidase systems in larvae. Furthermore, the study identified the impact of NPs on mitochondrial ultrastructural, resulting in mitochondrial depolarization and downregulation of mRNA expression related to the electron transport chain due to excessive ROS generation. Short-term exposure to NPs also triggered apoptosis and inflammation in zebrafish larvae, evident from significant up-regulation in mRNA expressions of proapoptotic factors and NF-κB proinflammatory signaling pathway, as well as increased transcription and protein levels of pro-inflammatory factors in larvae. Inhibition of intracellular excessive ROS effectively reduced the induction of apoptosis, NF-κB P65 nuclear migration levels, and cytokine secretion, underscoring OS as a pivotal factor throughout the process of apoptosis and inflammatory responses induced by NPs. This research significantly advances our comprehension of biological effects and underlying mechanisms of NPs in freshwater fish.

Engineering exosomes to reshape the immune microenvironment in breast cancer: Molecular insights and therapeutic opportunities

BACKGROUND

Breast cancer remains a global health challenge, necessitating innovative therapeutic approaches. Immunomodulation and immunotherapy have emerged as promising strategies for breast cancer treatment. Engineered exosomes are the sort of exosomes modified with surface decoration and internal therapeutic molecules. Through suitable modifications, engineered exosomes exhibit the capability to overcome the limitations associated with traditional therapeutic approaches. This ability opens up novel avenues for the development of more effective, personalized, and minimally invasive interventions.

MAIN BODY

In this comprehensive review, we explore the molecular insights and therapeutic potential of engineered exosomes in breast cancer. We discuss the strategies employed for exosome engineering and delve into their molecular mechanisms in reshaping the immune microenvironment of breast cancer.

CONCLUSIONS

By elucidating the contribution of engineered exosomes to breast cancer immunomodulation, this review underscores the transformative potential of this emerging field for improving breast cancer therapy.

HIGHLIGHTS

Surface modification of exosomes can improve the targeting specificity. The engineered exosome-loaded immunomodulatory cargo regulates the tumour immune microenvironment. Engineered exosomes are involved in the immune regulation of breast cancer.