GO-PEG Represses the Progression of Liver Inflammation via Regulating the M1/M2 Polarization of Kupffer Cells.

As a highly promising nanomaterial, exploring the impact of the liver, a vital organ, stands out as a crucial focus in the examination of its biological effects. Kupffer cells (KCs) are one of the first immune cells to contact with exotic-substances in liver. Therefore, this study investigates the immunomodulatory effects and mechanisms of polyethylene glycol-modified graphene oxide (GO-PEG) on KCs. Initial RNA-seq and KEGG pathway analyses reveal the inhibition of the TOLL-like receptor, TNF-α and NOD-like receptor pathways in continually stimulated KCs exposed to GO-PEG. Subsequent biological experiments validate that a 48-hour exposure to GO-PEG alleviates LPS-induced KCs immune activation, characterized by a shift in polarization from M1 to M2. The underlying mechanism involves the absorption of double-stranded RNA/single-stranded RNA, inhibiting the activation of TLR3 and TLR7 in KCs. Employing a Kupffer/AML12 cell co-culture model and animal studies, it is observed that GO-PEG indirectly inhibit oxidative stress, mitochondrial dysfunction, and apoptosis in AML12 cells, partially mitigating systemic inflammation and preserving liver tissue/function. This effect is attributed to the paracrine interaction between KCs and hepatocytes. These findings suggest a meaningful and effective strategy for treating liver inflammation, particularly when combined with anti-inflammatory drugs.

Research advance of occupational exposure risks and toxic effects of semiconductor nanomaterials.

In recent years, semiconductor nanomaterials, as one of the most promising and applied classes of engineered nanomaterials, have been widely used in industries such as photovoltaics, electronic devices, and biomedicine. However, occupational exposure is unavoidable during the production, use, and disposal stages of products containing these materials, thus posing potential health risks to workers. The intricacies of the work environment present challenges in obtaining comprehensive data on such exposure. Consequently, there remains a significant gap in understanding the exposure risks and toxic effects associated with semiconductor nanomaterials. This paper provides an overview of the current classification and applications of typical semiconductor nanomaterials. It also delves into the existing state of occupational exposure, methodologies for exposure assessment, and prevailing occupational exposure limits. Furthermore, relevant epidemiological studies are examined. Subsequently, the review scrutinizes the toxicity of semiconductor nanomaterials concerning target organ toxicity, toxicity mechanisms, and influencing factors. The aim of this review is to lay the groundwork for enhancing the assessment of occupational exposure to semiconductor nanomaterials, optimizing occupational exposure limits, and promoting environmentally sustainable development practices in this domain.

Safety assessment of graphene oxide and microcystin-LR complex: a toxicological scenario beyond physical mixture.

BACKGROUND: Nanomaterials have been widely used in electrochemistry, sensors, medicine among others applications, causing its inevitable environmental exposure. A raising question is the "carrier" effect due to unique surface properties of nanomaterials, which may collectively impact the bioavailability, toxicokinetic, distribution and biological effects of classic toxicants. Noteworthy, this aspect of information remains largely unexplored. METHODS: Here, we deliberately selected two entities to mimic this scenario. One is graphene oxide (GO), which is made in ton quantity with huge surface-area that provides hydrophilicity and π-π interaction to certain chemicals of unique structures. The other is Microcystin-LR (MCLR), a representative double-bond rich liver-toxic endotoxin widely distributed in aquatic-system. Firstly, the adsorption of GO and MCLR after meeting under environmental conditions was explored, and then we focused on the toxicological effect and related mechanism of GO-MCLR complex on human skin cutin forming cells (HaCaT cells) and normal liver cells (L02 cells). RESULTS: Abiotically, our study demonstrated that GO could effectively adsorb MCLR through hydrogen bonding and π-π interaction, the oxidation degree of GO-MCLR decreased significantly and surface defect level raised. Compared to GO or MCLR, GO-MCLR was found to induce more remarkable apoptosis and ferroptosis in both HaCaT and L02 cells. The underlying mechanism was that GO-MCLR induced stronger intracellular reactive oxygen species (ROS) and mtROS generation, followed by Fe2+ accumulation, mitochondrial dysfunction and cytoskeletal damage. CONCLUSIONS: These results suggest that the GO-MCLR complex formed by GO adsorption of MCLR may exhibit more toxic effects than the single material, which demonstrates the necessity for assessing nano-toxicant complexity. Our discovery may serve as a new toxicological paradigm in which nanomaterial mediated surface adsorption effects could impact the degree of cytotoxicity and toxicological mechanisms of classic toxins.

TFEB-lysosome pathway activation is associated with different cell death responses to carbon quantum dots in Kupffer cells and hepatocytes.

BACKGROUND: Carbon dot has been widely used in biomedical field as a kind of nanomaterial with low toxicity and high biocompatibility. CDs has demonstrated its unique advantages in assisted drug delivery, target diagnosis and targeted therapy with its small size and spontaneous fluorescence. However, the potential biosafety of CDs cannot be evaluated. Therefore, we focused on the study of liver, the target organ involved in CDs metabolism, to evaluate the risk of CDs in vitro. METHODS AND RESULTS: Liver macrophage KUP5 cells and normal liver cells AML12 cells were incubated in CDs at the same concentration for 24 h to compare the different effects under the same exposure conditions. The study found that both liver cell models showed ATP metabolism disorder, membrane damage, autophagosome formation and lysosome damage, but the difference was that, KUP5 cells exhibited more serious damage than AML12 cells, suggesting that immunogenic cell type is particularly sensitive to CDs. The underlying mechanism of CDs-induced death of the two hepatocyte types were also assessed. In KUP5 cells, death was caused by inhibition of autophagic flux caused by autophagosome accumulation, this process that was reversed when autophagosome accumulation was prevented by 3-MA. AML12 cells had no such response, suggesting that the accumulation of autophagosomes caused by CDs may be specific to macrophages. CONCLUSION: Activation of the TFEB-lysosome pathway is important in regulating autophagy and apoptosis. The dual regulation of ERK and mTOR phosphorylation upstream of TFEB influences the death outcome of AML12 cells. These findings provide a new understanding of how CDs impact different liver cells and contribute to a more complete toxicological safety evaluation of CDs.

Panax quinquefolius saponins and panax notoginseng saponins attenuate myocardial hypoxia-reoxygenation injury by reducing excessive mitophagy.

OBJECTIVE: Panax quinquefolius saponins (PQS) and Panax notoginseng saponins (PNS) are key bioactive compounds in Panax quinquefolius L. and Panax notoginseng, commonly used in the treatment of clinical ischemic heart disease. However, their potential in mitigating myocardial ischemia-reperfusion injury remains uncertain. This study aims to evaluate the protective effects of combined PQS and PNS administration in myocardial hypoxia/reoxygenation (H/R) injury and explore the underlying mechanisms. METHODS: To investigate the involvement of HIF-1α/BNIP3 mitophagy pathway in the myocardial protection conferred by PNS and PQS, we employed small interfering BNIP3 (siBNIP3) to silence key proteins of the pathway. H9C2 cells were categorized into four groups: control, H/R, H/R + PQS + PNS, and H/R + PQS + PNS+siBNIP3. Cell viability was assessed by Cell Counting Kit-8, apoptosis rates determined via flow cytometry, mitochondrial membrane potential assessed with the JC-1 fluorescent probes, intracellular reactive oxygen species detected with 2',7'-dichlorodihydrofluorescein diacetate, mitochondrial superoxide production quantified with MitoSOX Red, and autophagic flux monitored with mRFP-GFP-LC3 adenoviral vectors. Autophagosomes and their ultrastructure were visualized through transmission electron microscopy. Moreover, mRNA and protein levels were analyzed via real-time PCR and Western blotting. RESULTS: PQS + PNS administration significantly increased cell viability, reduced apoptosis, lowered reactive oxygen species levels and mitochondrial superoxide production, mitigated mitochondrial dysfunction, and induced autophagic flux. Notably, siBNIP3 intervention did not counteract the cardioprotective effect of PQS + PNS. The PQS + PNS group showed downregulated mRNA expression of HIF-1α and BNIP3, along with reduced HIF-1α protein expression compared to the H/R group. CONCLUSIONS: PQS + PNS protects against myocardial H/R injury, potentially by downregulating mitophagy through the HIF-1α/BNIP3 pathway.

Preliminary study on the E-liquid and aerosol on the neurobehavior of C. elegans.

E-cigarettes, also known as electronic nicotine delivery systems (ENDS), are mainly used among adolescents and young adults. Similar to traditional cigarettes, different concentrations of nicotine are also added to E-cigarette's liquid (E-liquid), but due to the supplementation of chemicals such as propylene glycol (PG), vegetable glycerin (VG) and flavors, it is difficult to determine the risk after using E-cigarettes. And given to the specificity of the aerosol particle composition and atomization process of E-cigarettes, it is necessary to assess the neurotoxic effects of long-term E-cigarettes use. In this study, two commercial nicotine-containing (5%) and nicotine-free E-liquids were diluted to investigate the neurobehavioral changes and addictive tendencies of developing C. elegans after sub-chronic exposure to E-liquid. The results showed that sub-chronic exposure of E-liquid could lead to impaired growth and development of nematodes, abnormal general neuromotor behavior and advanced learning and memory behavior, and nicotine-containing E-liquid could also lead to increased addiction tendency of nematodes. Although the damage effect of nicotine free E-liquid is smaller than that of the nicotine-containing group, its toxic effect cannot be ignored. Further analysis of the neurotoxicity mechanism found that redox imbalance-mediated mitochondrial stress and aging may be important causes of E-liquid-induced biological damage. The biosafety of e-cigarette aerosols was also included in the assessment. The study found that the heated atomization process did not alter the E-liquid components, and E-cigarette aerosols still have the effect of interfering with the growth and development of nematodes and neurobehavior, and its addictive nature is also of concern. This study can provide new ideas for future studies on the neurotoxic effects and safety assessment of the E-cigarettes, and provide theoretical reference for the study on the injury mechanism of E-cigarettes.

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.

Nose-to-brain translocation and nervous system injury in response to indium tin oxide nanoparticles of long-term low-dose exposures.

Indium tin oxide (ITO) is a semiconductor nanomaterial with broad application in liquid crystal displays, solar cells, and electrochemical immune sensors. It is worth noting that, with the gradual increase in worker exposure opportunities, the exposure risk in occupational production cannot be ignored. At present, the toxicity of ITO mainly focuses on respiratory toxicity. ITO inhaled through the upper respiratory tract can cause pathological changes such as interstitial pneumonia and pulmonary fibrosis. Still, extrapulmonary toxicity after nanoscale ITO nanoparticle (ITO NPs) exposure, such as long-term effects on the central nervous system, should also be of concern. Therefore, we set up exposure dose experiments (0 mg·kg-1, 3.6 mg·kg-1, and 36 mg·kg-1) based on occupational exposure limits to treat C57BL/6 mice via nasal drops for 15 weeks. Moreover, we conducted a preliminary assessment of the neurotoxicity of ITO NPs (20-30 nm) in vivo. The results indicated that ITO NPs can cause diffuse inflammatory infiltrates in brain tissue, increased glial cell responsiveness, abnormal neuronal cell lineage transition, neuronal migration disorders, and neuronal apoptosis related to the oxidative stress induced by ITO NPs exposure. Hence, our findings provide useful information for the fuller risk assessment of ITO NPs after occupational exposure.

How UV radiation and pH alternation impact graphene oxide mediated environmental toxicant adsorption and resulting safety characteristics - A toxicology study beyond a classic carrier effect.

Once released into water, the widely used graphene oxide (GO) is likely to adsorb classical environmental pollutants, exemplified by Microcystin-LR (MCLR) that is a representative double-bond rich liver-toxic endotoxin. While GO-mediated carrier effect is fairly predictable, the involvement of environmental factors like UV and pH may add additional level of sophistication as these factors may impact the adsorption capacity of GO to MCLR. Here, we firstly investigated the changes of GO structure under different UV-radiation durations and pH conditions with a view to establish the correlation in terms of MCLR adsorption onto GO. We demonstrated that GO reduction especially oxygen-containing groups reduction induced by UV- radiation caused the compromised adsorption MCLR capacity on GO. Besides, the higher pH decreased the non-biological MCLR adsorption to GO by reducing GO defect sites and increasing electrostatic repulsion. These abiotic discoveries were further investigated to compare the safety features of GO-MCLR complex. Under dark condition (pH = 7), we revealed the cytotoxicity of GO-MCLR to normal liver cells, which involved the ROS generation and cell ferroptosis caused by Fe2+ accumulation. Introduction of UV and pH alternation in environment impacted GO-mediated environmental toxicant adsorption and resulting safety characteristics, which reminded us environmental factors should not be ignored in the GO-mediated carrier effect.

Intracellular reactive oxygen species trigger mitochondrial dysfunction and apoptosis in cadmium telluride quantum dots-induced liver damage.

Quantum dots (QDs), also known as semiconductor QDs, have specific photoelectricproperties which find application in bioimaging, solar cells, and light-emitting diodes (LEDs). However, the application of QDs is often limited by issues related to health risks and potential toxicity. The purpose of this study was to provide evidence regarding the safety of cadmium telluride (CdTe) QDs by exploring the detailed mechanisms involved in its hepatotoxicity. This study showed that CdTe QDs can increase reactive oxygen species (ROS) in hepatocytes after being taken up by hepatocytes, which triggers a significant mitochondrial-dependent apoptotic pathway, leading to hepatocyte apoptosis. CdTe QDs-induce mitochondrial cristae abnormality, adenosine triphosphate (ATP) depletion, and mitochondrial membrane potential (MMP) depolarization. Meanwhile, CdTe QDs can change the morphology, function, and quantity of mitochondria by reducing fission and intimal fusion. Importantly, inhibition of ROS not only protects hepatocyte viability but can also interfere with apoptosis and activation of mitochondrial dysfunction. Similarly, the exposure of CdTe QDs in Institute of Cancer Research (ICR) mice showed that CdTe QDs caused oxidative damage and apoptosis in liver tissue. NAC could effectively remove excess ROS could reduce the level of oxidative stress and significantly alleviate CdTe QDs-induced hepatotoxicity in vivo. CdTe QDs-induced hepatotoxicity may originate from the generation of intracellular ROS, leading to mitochondrial dysfunction and apoptosis, which was potentially regulated by mitochondrial dynamics. This study revealed the nanobiological effects of CdTe QDs and the intricate mechanisms involved in its toxicity at the tissue, cell, and subcellular levels and provides information for narrowing the gap between in vitro and in vivo animal studies and a safety assessment of QDs.

The involvement of DRP1-mediated caspase-1 activation in inflammatory response by urban particulate matter in EA.hy926 human vascular endothelial cells.

Atmospheric particulate matter (PM) has been reported to be closely related to cardiovascular adverse events. However, the underlying mode of action remains to be elucidated. Previous studies have documented that PM induces mitochondrial damage and inflammation, the relation between these two biological outcomes is still unclear though. In this study, we used EA.hy926 human vascular endothelial cells and a standard PM, PM SRM1648a to study the potential effects of mitochondrial dysfunction on endothelial inflammatory responses. As a result, PM SRM1648a changes mitochondrial morphology and interrupts mitochondrial dynamics with a persistent tendency of fission in a dose-dependent manner. Additionally, the caspase-1/IL-1ß axis is involved in inflammatory responses but not cell pyroptosis in EA.hy926 cells following the exposure to PM SRM1648a. The activation of caspase-1 has implications in inflammation but not pyroptosis, because caspase-1-dependent pyroptosis is not the main modality of cell death in PM SRM1648a-treated EA.hy926 cells. With regard to the association between mitochondrial damage and inflammation in the case of particle stimulation, DRP1-mediated mitochondrial fission is responsible for inflammatory responses as a result of caspase-1 activation. The current study showed that PM SRM1648a has the ability to disturb mitochondrial dynamics, and trigger endothelial inflammation via DRP1/caspase-1/IL-1ß regulatory pathway. In a conclusion, mitochondrial fission enables EA.hy926 cells to facilitate caspase-1 activation in response to PM SRM1648a, which is a crucial step for inflammatory reaction in vascular endothelial cells.

Ambient particulate matter triggers defective autophagy and hijacks endothelial cell renewal through oxidative stress-independent lysosomal impairment.

Ambient particulate matter (APM) has been authenticated to exert hazards on human vascular endothelial cells, including abnormal autophagy. However, the potential reasons for autophagosome accumulation are still obscure. Since autophagy is a dynamic process, it is imperative to systemically consider the autophagic induction combined with its degradation to reflect realistic scenarios. Therefore, in the current study, different exposure durations were initially employed for the detection of autophagic marker proteins to assess the dynamic autophagic state preliminarily. Additionally, LC3 turn-over and autophagic flux assays were used to determine the specific cause of LC3II upregulation in EA.hy926 human vascular endothelial cells by a type of standard urban particulate matter, PM SRM1648a. As a result, PM SRM1648a stimulates excess autophagic vacuoles in EA. hy926 cells, in which the underlying causes are probably different at varying incubation endpoints. Intriguingly, LC3II upregulation was due to the intensifying autophagic initiation after 6 h of exposure, whereas as exposure period was extended to 24 h, overloaded autophagic vacuoles were attributed to the defective autophagy. Mechanistically, PM SRM1648a damages EA. hy926 cells by inducing lysosomal disequilibrium and resultant autophagic malfunction which are not directly mediated by oxidative stress. These data indicate that appropriate maintenance of lysosomal function and autophagic flux is probably a protective measure against APM-induced endothelial cell damage.

Reactive oxygen species trigger NF-κB-mediated NLRP3 inflammasome activation involvement in low-dose CdTe QDs exposure-induced hepatotoxicity.

Cadmium telluride (CdTe) quantum dots (QDs) can be employed as imaging and drug delivery tools; however, the toxic effects and mechanisms of low-dose exposure are unclear. Therefore, this pioneering study focused on hepatic macrophages (Kupffer cells, KCs) and explored the potential damage process induced by exposure to low-dose CdTe QDs. In vivo results showed that both 2.5 µM/kg·bw and 10 µM/kg·bw could both activate KCs to cause liver injury, and produce inflammation by disturbing antioxidant levels. Abnormal liver function further verified the risks of low-dose exposure to CdTe QDs. The KC model demonstrated that low-dose CdTe QDs (0 nM, 5 nM and 50 nM) can be absorbed by cells and cause severe reactive oxygen species (ROS) production, oxidative stress, and inflammation. Additionally, the expression of NF-κB, caspase-1, and NLRP3 were decreased after pretreatment with ROS scavenging agent N-acetylcysteine (NAC, 5 mM pretreated for 2 h) and the NF-κB nuclear translocation inhibitor Dehydroxymethylepoxyquinomicin (DHMEQ, 10 µg/mL pretreatment for 4 h) respectively. The results indicate that the activation of the NF-κB pathway by ROS not only directly promotes the expression of inflammatory factors such as pro-IL-1ß, TNF-α, and IL-6, but also mediates the assembly of NLRP3 by ROS activation of NF-κB pathway, which indirectly promotes the expression of NLRP3. Finally, a high-degree of overlap between the expression of the NF-κB and NLRP3 and the activated regions of KCs, further support the importance of KCs in inflammation induced by low-dose CdTe QDs.