Proinflammatory Effect of Carbon-Based Nanomaterials: In Vitro Study on Stimulation of Inflammasome NLRP3 via Destabilisation of Lysosomes

Long circulating liposomal platform utilizing hydrophilic polymer-based surface modification: preparation, characterisation, and biological evaluation

Liposomes are one of the most important drug delivery vectors, nowadays used in clinics. In general, polyethylene glycol (PEG) is used to ensure the stealth properties of the liposomes. Here, we have employed hydrophilic, biocompatible and highly non-fouling N-(2-hydroxypropyl) methacrylamide (HPMA)-based copolymers containing hydrophobic cholesterol anchors for the surface modification of liposomes, which were prepared by the method of lipid film hydration and extrusion through 100 nm polycarbonate filters. Efficient surface modification of liposomes was confirmed by transmission electron microscopy, atomic force microscopy, and gradient ultracentrifugation. The ability of long-term circulation in the vascular bed was demonstrated in rabbits after i.v. application of fluorescently labelled liposomes. Compared to PEGylated liposomes, HPMA-based copolymer-modified liposomes did not induce specific antibody formation and did not activate murine and human complement. Compared with PEGylated liposomes, HPMA-based copolymer-modified liposomes showed a better long-circulating effect after repeated administration. HPMA-based copolymer-modified liposomes thus represent suitable new candidates for a generation of safer and improved liposomal drug delivery platforms.

Role of NLRP3 inflammasome in nanoparticle adjuvant-mediated immune response

The nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family pyrin domain-containing 3 (NLRP3) inflammasome is pivotal in orchestrating the immune response induced by nanoparticle adjuvants. Understanding the intricate mechanisms underlying the activation of NLRP3 inflammasome by these adjuvants is crucial for deciphering their immunomodulatory properties. This review explores the involvement of the NLRP3 inflammasome in mediating immune responses triggered by nanoparticle adjuvants. It delves into the signaling pathways and cellular mechanisms involved in NLRP3 activation, highlighting its significance in modulating the efficacy and safety of nanoparticle-based adjuvants. A comprehensive grasp of the interplay between NLRP3 inflammasome and nanoparticle adjuvants holds promise for optimizing vaccine design and advancing immunotherapeutic strategies.

Comprehensive Analysis of Predictive Value and the potential therapeutic target of NLRP3 inflammasome in glioma based on tumor microenvironment

BACKGROUND

Glioma exhibits high recurrence rates and poor prognosis. The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome plays a crucial role in inflammation. There is a lack of research exploring the NLRP3 in glioma.

METHODS

We used several databases, networks, Western blotting, multiple immunofluorescence staining to analyze the role of NLRP3 in inflammatory tumor microenvironment (TME).

RESULTS

NLRP3 is higher-expression in glioma with a low mutation load. NLRP3 expression is linked to the infiltration of immune cells, chemokines, immunomodulators, and the TME. Signaling pathways, co-expression genes and interacting proteins contribute to the up-regulation of NLRP3. Patients responding to immunotherapy positively tend to have lower NLRP3 expression relating to the overall survival based on nomogram. Sensitivity to molecular medicines is observed in relation to NLRP3.

CONCLUSION

The NLRP3 inflammasome plays a pivotal role in TME which could serve as a higher predictive value biomarker and therapeutic target for glioma treatment.

Carbon dot-based nanomaterials: a promising future nano-platform for targeting tumor-associated macrophages

The tumor microenvironment (TME) is the internal environment that tumors depend on for survival and development. Tumor-associated macrophages (TAMs), as an important part of the tumor microenvironment, which plays a crucial role in the occurrence, development, invasion and metastasis of various malignant tumors and has immunosuppressant ability. With the development of immunotherapy, eradicating cancer cells by activating the innate immune system has yielded encouraging results, however only a minority of patients show a lasting response. Therefore, in vivo imaging of dynamic TAMs is crucial in patient-tailored immunotherapy to identify patients who will benefit from immunotherapy, monitor efficacy after treatment, and identify alternative strategies for non-responders. Meanwhile, developing nanomedicines based on TAMs-related antitumor mechanisms to effectively inhibit tumor growth is expected to become a promising research field. Carbon dots (CDs), as an emerging member of the carbon material family, exhibit unexpected superiority in fluorescence imaging/sensing, such as near infrared imaging, photostability, biocompatibility and low toxicity. Their characteristics naturally integrate therapy and diagnosis, and when CDs are combined with targeted chemical/genetic/photodynamic/photothermal therapeutic moieties, they are good candidates for targeting TAMs. We concentrate our discussion on the current learn of TAMs and describe recent examples of macrophage modulation based on carbon dot-associated nanoparticles, emphasizing the advantages of their multifunctional platform and their potential for TAMs theranostics.

Diverse Pathways of Engineered Nanoparticle-Induced NLRP3 Inflammasome Activation

With the rapid development of engineered nanomaterials (ENMs) in biomedical applications, their biocompatibility and cytotoxicity need to be evaluated properly. Recently, it has been demonstrated that inflammasome activation may be a vital contributing factor for the development of biological responses induced by ENMs. Among the inflammasome family, NLRP3 inflammasome has received the most attention because it directly interacts with ENMs to cause the inflammatory effects. However, the pathways that link ENMs to NLRP3 inflammasome have not been thoroughly summarized. Thus, we reviewed recent findings on the role of major ENMs properties in modulating NLRP3 inflammasome activation, both in vitro and in vivo, to provide a better understanding of the underlying mechanisms. In addition, the interactions between ENMs and NLRP3 inflammasome activation are summarized, which may advance our understanding of safer designs of nanomaterials and ENM-induced adverse health effects.

Immunotoxicity of Carbon-Based Nanomaterials, Starring Phagocytes

In the field of science, technology and medicine, carbon-based nanomaterials and nanoparticles (CNMs) are becoming attractive nanomaterials that are increasingly used. However, it is important to acknowledge the risk of nanotoxicity that comes with the widespread use of CNMs. CNMs can enter the body via inhalation, ingestion, intravenously or by any other route, spread through the bloodstream and penetrate tissues where (in both compartments) they interact with components of the immune system. Like invading pathogens, CNMs can be recognized by large numbers of receptors that are present on the surface of innate immune cells, notably monocytes and macrophages. Depending on the physicochemical properties of CNMs, i.e., shape, size, or adsorbed contamination, phagocytes try to engulf and process CNMs, which might induce pro/anti-inflammatory response or lead to modulation and disruption of basic immune activity. This review focuses on existing data on the immunotoxic potential of CNMs, particularly in professional phagocytes, as they play a central role in processing and eliminating foreign particles. The results of immunotoxic studies are also described in the context of the entry routes, impacts of contamination and means of possible elimination. Mechanisms of proinflammatory effect depending on endocytosis and intracellular distribution of CNMs are highlighted as well.

Plant-derived bioactive compounds regulate the NLRP3 inflammasome to treat NAFLD

Non-alcoholic fatty liver disease (NAFLD) is a liver disorder characterized by abnormal accumulation of hepatic fat and inflammatory response with complex pathogenesis. Over activation of the pyrin domain-containing protein 3 (NLRP3) inflammasome triggers the secretion of interleukin (IL)-1β and IL-18, induces pyroptosis, and promotes the release of a large number of pro-inflammatory proteins. All of which contribute to the development of NAFLD. There is a great deal of evidence indicating that plant-derived active ingredients are effective and safe for NAFLD management. This review aims to summarize the research progress of 31 active plant-derived components (terpenoids, flavonoids, alkaloids, and phenols) that alleviate lipid deposition, inflammation, and pyroptosis by acting on the NLRP3 inflammasome studied in both in vitro and in vivo NAFLD models. These studies confirmed that the NLRP3 inflammasome and its related genes play a key role in NAFLD amelioration, providing a starting point for further study on the correlation of plant-derived compounds treatment with the NLRP3 inflammasome and NAFLD.

Activation and Pharmacological Regulation of Inflammasomes

Inflammasomes are intracellular signaling complexes of the innate immune system, which is part of the response to exogenous pathogens or physiological aberration. The multiprotein complexes mainly consist of sensor proteins, adaptors, and pro-caspase-1. The assembly of the inflammasome upon extracellular and intracellular cues drives the activation of caspase-1, which processes pro-inflammatory cytokines IL-1β and IL-18 to maturation and gasdermin-D for pore formation, leading to pyroptosis and cytokine release. Inflammasome signaling functions in numerous infectious or sterile inflammatory diseases, including inherited autoinflammatory diseases, metabolic disorders, cardiovascular diseases, cancers, neurodegenerative disorders, and COVID-19. In this review, we summarized current ideas on the organization and activation of inflammasomes, with details on the molecular mechanisms, regulations, and interventions. The recent developments of pharmacological strategies targeting inflammasomes as disease therapeutics were also covered.

Cationic Carbon Nanoparticles Induce Inflammasome-Dependent Pyroptosis in Macrophages via Lysosomal Dysfunction

Carbon nanomaterials, including carbon dots (CDs), form a growing family of engineered nanoparticles (NPs) with widespread applications. As the rapid expansion of nanotechnologies raises safety concerns, interaction of NPs with the immune system is receiving a lot of attention. Recent studies have reported that engineered NPs may induce macrophage death by pyroptosis. Therefore, this study investigated whether cationic CDs induce pyroptosis in human macrophages and assessed the role of inflammasome and lysosome in this process. Cationic CDs were synthetized by microwave-assisted pyrolysis of citric acid and high molecular weight branched polyethyleneimine. The NPs evoked a dose-dependent viability loss in THP-1-derived macrophages. A cell leakage, an increase in IL-1β secretion and an activation of caspase-1 were also observed in response to the NPs. Inhibition of caspase-1 decreased CD-induced cell leakage and IL-1β secretion, while restoring cell viability. Besides, CDs triggered swelling and loss of integrity of lysosome, and inhibition of the lysosomal enzyme cathepsin B decreased CD-induced IL-1β secretion. Thus, our data provide evidence that cationic CDs induce inflammasome-dependent pyroptosis in macrophages via lysosomal dysfunction.

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.

The Role of the NLRP3 Inflammasome in Mediating Glomerular and Tubular Injury in Diabetic Nephropathy

The NOD-like receptor protein 3 (NLRP3) inflammasome is a multi-protein signalling complex integral to the chronic inflammatory response, activated in response to sterile and non-sterile cellular damage. The assembly and activation of the NLRP3 inflammasome comprise a two-step process involving nuclear factor kappa B (NFkB)-mediated priming, followed by canonical, non-canonical or alternative signalling pathways. These result in the maturation and release of inflammatory cytokines interleukin 1 beta (IL1ß) and interleukin-18 (IL18), which are associated with chronic inflammatory conditions including diabetic kidney disease. Diabetic nephropathy is a condition affecting ∼40% of people with diabetes, the key underlying pathology of which is tubulointerstitial inflammation and fibrosis. There is growing evidence to suggest the involvement of the NLRP3 inflammasome in this chronic inflammation. Early deterioration of kidney function begins in the glomerulus, with tubular inflammation dictating the progression of late-stage disease. Priming and activation of the NLRP3 inflammasome have been linked to several clinical markers of nephropathy including proteinuria and albuminuria, in addition to morphological changes including mesangial expansion. Treatment options for diabetic nephropathy are limited, and research that examines the impact of directly targeting the NLRP3 inflammasome, or associated downstream components are beginning to gain favour, with several agents currently in clinical trials. This review will explore a role for NLRP3 inflammasome activation and signalling in mediating inflammation in diabetic nephropathy, specifically in the glomerulus and proximal tubule, before briefly describing the current position of therapeutic research in this field.

The Effect of Chronic Exposure of Graphene Nanoplates on the Viability and Motility of A549 Cells

Graphene and its derivatives are popular nanomaterials used worldwide in many technical fields and biomedical applications. Due to such massive use, their anticipated accumulation in the environment is inevitable, with a largely unknown chronic influence on living organisms. Although repeatedly tested in chronic in vivo studies, long-term cell culture experiments that explain the biological response to these nanomaterials are still scarce. In this study, we sought to evaluate the biological responses of established model A549 tumor cells exposed to a non-toxic dose of pristine graphene for eight weeks. Our results demonstrate that the viability of the A549 cells exposed to the tested graphene did not change as well as the rate of their growth and proliferation despite nanoplatelet accumulation inside the cells. In addition, while the enzymatic activity of mitochondrial dehydrogenases moderately increased in exposed cells, their overall mitochondrial damage along with energy production changes was also not detected. Conversely, chronic accumulation of graphene nanoplates in exposed cells was detected, as evidenced by electron microscopy associated with impaired cellular motility.

The Dose- and Time-Dependent Cytotoxic Effect of Graphene Nanoplatelets: In Vitro and In Vivo Study

Graphene-based nanomaterials received attention from scientists due to their unique properties: they are highly conductive, mechanically resistant and elastic. These materials can be used in different sectors of society from electronic energy storage in industry to biomedical applications. This study evaluates the influence of graphene nanoplatelets in vitro and in vivo. The toxicological influence of graphene nanoplatelets (GPs) was analyzed by cytotoxic methods, the change of cell proliferation was assessed in real-time, and the effect of GPs on a living organism was evaluated in an animal model using histopathological examination. We analyzed two types of GP administration: intratracheal and peroral. We found dose- and time-dependent cytotoxic effects of GPs in vitro; the concentration above 50 μg/mL increased the cytotoxicity significantly. The real-time analysis confirmed these data; the cells exposed to a high concentration of GPs for a longer time period resulted in a decrease in cell index which indicated lower cell viability. Histopathological examination revealed thickened alveolar septa and accumulation of GPs in the endocardium after intratracheal exposure. Peroral administration did not reveal any morphological changes. This study showed the dose- and time-dependent cytotoxic potential of graphene nanoplatelets in in vitro and in vivo models.

Modified Nanodiamonds as a Means of Polymer Surface Functionalization. From Fouling Suppression to Biosensor Design

The development of different methods for tuning surface properties is currently of great interest. The presented work is devoted to the use of modified nanodiamonds to control the wetting and biological fouling of polymers using optical sensors as an example. We have shown that, depending on the type of modification and the amount of nanodiamonds, the surface of the same fluorinated polymer can have both bactericidal properties and, on the contrary, good adhesion to the biomaterial. The precise control of wetting and biofouling properties of the surface was achieved by the optimization of the modified nanodiamonds thermal anchoring conditions. In vitro and in vivo tests have shown that the fixation of amine functional groups leads to inhibition of biological activity, while the presence of a large number of polar groups of mixed composition (amide and acid chloride) promotes adhesion of the biomaterial and allows one to create a biosensor on-site. A comprehensive study made it possible to establish that in the first 5 days the observed biosensor response is provided by cells adhered to the surface due to the cell wall interaction. On the 7th day, the cells are fixed by means of the polysaccharide matrix, which provides much better retention on the surface and a noticeably greater response to substrate injections. Nevertheless, it is important to note that even 1.5 h of incubation is sufficient for the formation of the reliable bioreceptor on the surface with the modified nanodiamonds. The approach demonstrated in this work makes it possible to easily and quickly isolate the microbiome on the surface of the sensor and perform the necessary studies of its substrate specificity or resistance to toxic effects.

Dietary Docosahexaenoic Acid as a Potential Treatment for Semi-acute and Chronic Particle-Induced Pulmonary Inflammation in Balb/c Mice

Acute and chronic inflammation are vital contributing factors to pulmonary diseases which can be triggered by exposure to occupational and man-made particles; however, there are no established treatments. One potential treatment shown to have anti-inflammatory capabilities is the dietary supplement docosahexaenoic acid (DHA), an omega-3 polyunsaturated fatty acid found in fish oil. DHA's anti-inflammatory mechanisms are unclear for particle-induced inflammation; therefore, this study evaluated DHA as a prophylactic treatment for semi-acute and chronic particle-induced inflammation in vivo. Balb/c mice were fed a control or 1% DHA diet and exposed to dispersion media, an inflammatory multi-walled carbon nanotube (MWCNT), or crystalline silica (SiO₂) either once (semi-acute) or once a week for 4 weeks (chronic). The hypothesis was that DHA will decrease pulmonary inflammatory markers in response to particle-induced inflammation. Results indicated that DHA had a trending anti-inflammatory effect in mice exposed to MWCNT. There was a general decrease in inflammatory signals within the lung lavage fluid and upregulation of M2c macrophage gene expression in the spleen tissue. In contrast, mice exposed to SiO₂ while on the DHA diet significantly increased most inflammatory markers. However, DHA stabilized the phagolysosomal membrane upon prolonged treatment. This indicated that DHA treatment may depend upon certain inflammatory particle exposures as well as the length of the exposure.

Targeting NLRP3 Inflammasome in the Treatment Of Diabetes and Diabetic Complications: Role of Natural Compounds from Herbal Medicine

Diabetes, a common metabolic disease with various complications, is becoming a serious global health pandemic. So far there are many approaches in the management of diabetes; however, it still remains irreversible due to its complicated pathogenesis. Recent studies have revealed that nucleotide-binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome plays a vital role in the progression of diabetes and many of its complications, making it a promising therapeutic target in pharmaceutical design. Natural derived herbal medicine, known for its utilization of natural products such as herbs or its bioactive ingredients, is shown to be able to ameliorate hyperglycemia-associated symptoms and to postpone the progression of diabetic complications due to its anti-inflammatory and anti-oxidative properties. In this review, we summarized the role of NLRP3 inflammasome in diabetes and several diabetic complications, as well as 31 active compounds that exert therapeutic effect on diabetic complications via inhibiting NLRP3 inflammasome. Improving our understanding of these promising candidates from natural compounds in herbal medicine targeting NLRP3 inflammasome inspires us the relationship between inflammation and metabolic disorders, and also sheds light on searching potential agents or therapies in the treatment of diabetes and diabetic complications.

Carbon-Based Nanomaterials Increase Reactivity of Primary Monocytes towards Various Bacteria and Modulate Their Differentiation into Macrophages

The evaluation of carbon-based nanomaterials' (C-BNMs') interactions with the immune system, notably their ability to cause inflammation, is a critical step in C-BNM health risk assessment. Particular attention should be given to those C-BNMs that do not cause direct cytotoxicity or inflammation on their own. However, the intracellular presence of these non-biodegradable nanomaterials could dysregulate additional cell functions. This is even more crucial in the case of phagocytes, which are the main mediators of defensive inflammation towards pathogens. Hence, our study was focused on multi-walled carbon nanotubes (MWCNTs) and two different types of graphene platelets (GPs) and whether their intracellular presence modulates a proinflammatory response from human primary monocytes towards common pathogens. Firstly, we confirmed that all tested C-BNMs caused neither direct cytotoxicity nor the release of tumour necrosis factor α (TNF-α), interleukin (IL)-6 or IL-10. However, such pre-exposed monocytes showed increased responsiveness to additional bacterial stimuli. In response to several types of bacteria, monocytes pre-treated with GP1 produced a significantly higher quantity of TNF-α, IL-6 and IL-10. Monocytes pre-treated with MWCNTs produced increased levels of IL-10. All the tested C-BNMs enhanced monocyte phagocytosis and accelerated their differentiation towards macrophages. This study confirms the immunomodulatory potential of C-BNMs.

In Vitro Assessment of the Genotoxic Potential of Pristine Graphene Platelets

(1) Background: Graphene is a two-dimensional atomic structure with a wide range of uses, including for biomedical applications. However, knowledge of its hazards is still limited. This work brings new cytotoxic, cytostatic, genotoxic and immunotoxic data concerning the in vitro exposure of human cell line to two types of graphene platelets (GP). It also contributes to the formation of general conclusions about the health risks of GP exposure. (2) Methods: In vitro exposure of a THP-1 cell line to three concentrations of two GP over 40 h. The cytotoxic potential was assessed by the measurement of LDH and glutathione (ROS) and by a trypan blue exclusion assay (TBEA); the cytostatic and genotoxic potential were assessed by the cytokinesis-block micronucleus (CBMN) test; and the immunotoxic potential was assessed by the measurement of IL-6, IL-10 and TNF-α. (3) Results: We found a significant dose-dependent increase in DNA damage (CBMN). The lowest observed genotoxic effect levels (LOGEL) were 5 µg/mL (GP1) and 30 µg/mL (GP2). We found no significant leaking of LDH from cells, increase in dead cells (TBEA), induction of ROS, increased levels of cytostasis, or changes in IL-6, IL-10 and TNF-α levels. (4) Conclusions: The genotoxicity increased during the short-term in vitro exposure of THP-1 to two GP. No increase in cytotoxicity, immunotoxicity, or cytostasis was observed.

pH Sensitive Dextran Coated Fluorescent Nanodiamonds as a Biomarker for HeLa Cells Endocytic Pathway and Increased Cellular Uptake

Fluorescent nanodiamonds are a useful for biosensing of intracellular signaling networks or environmental changes (such as temperature, pH or free radical generation). HeLa cells are interesting to study with these nanodiamonds since they are a model cell system that is widely used to study cancer-related diseases. However, they only internalize low numbers of nanodiamond particles very slowly via the endocytosis pathway. In this work, we show that pH-sensitive, dextran-coated fluorescent nanodiamonds can be used to visualise this pathway. Additionally, this coating improved diamond uptake in HeLa cells by 5.3 times (*** p < 0.0001) and decreased the required time for uptake to only 30 min. We demonstrated further that nanodiamonds enter HeLa cells via endolysosomes and are eventually expelled by cells.

[Effects of length and chemical modification on the activation of vascular endothelial cells induced by multi walled carbon nanotubes]

OBJECTIVE

To investigate the effects of multi-walled carbon nanotubes (MWCNTs) with different length or chemical modification on endothelial cell activation and to explore the role of nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome.

METHODS

MWCNTs were characterized by dynamic light scattering (DLS) after being suspended in culture medium. The immortalized mouse cerebral microvascular endothelial cell line b.End3 was treated with short MWCNTs (S-MWCNT, 0.5 to 2 μm), long MWCNTs (L-MWCNT, 10 to 30 μm) and the above long MWCNTs functionalized by carboxyl-(L-MWCNT-COOH), amino-(L-MWCNT-NH₂) or hydroxyl-(L-MWCNT-OH) modification. Cytotoxicity of MWCNTs in b.End3 cells was determined by cell counting kit-8 (CCK-8) assay and lactate dehydrogenase (LDH) release assay, and non-toxic low dose was selected for subsequent experiments. Effects of all types of MWCNTs on the endothelial activation of b.End3 were determined by the measurement of vascular cell adhesion molecule-1 (VCAM-1) concentration in cell supernatant and adhesion assay of human monocytic cell line THP-1 to b.End3.To further elucidate the mechanism involved, the protein expressions of nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3(NLRP3) in cells treated with S-MWCNT, L-MWCNT and L-MWCNT-COOH were measured by Western blot.

RESULTS

At a higher concentration (125 μg/cm²) and treated for 24 h, all types of MWCNTs significantly inhibited viability of b.End3 cells. At a sub-toxic concentration (6.25 μg/cm²), all types of MWCNTs treated for 12 h significantly induced the activation of b.End3 cells, as evidenced by the elevated VCAM-1 release and THP-1 adhesion. Compared with S-MWCNT, L-MWCNT significantly promoted endothelial cell activation. L-MWCNT and L-MWCNT-COOH activated b.End3 cells to a similar extent. Furthermore, treatment with S-MWCNT, L-MWCNT and L-MWCNT-COOH increased NLRP3 expression in a time-dependent manner at 6.25 μg/cm². Compared with S-MWCNT, cells treated with L-MWCNT for 4 h and 12 h exhibited significantly increased protein expressions of NLRP3. However, no significant differences were detected in the level of NLRP3 protein in cells treated with L-MWCNT and L-MWCNT-COOH.

CONCLUSION

Compared with the surface chemical modification, length changes of MWCNTs exerted more influence on endothelial cell activation, which may be related to the activation of NLRP3 inflammasome. Our study contributes further understanding of the impact of MWCNTs on endothelial cells, which may have implications for the improvement of safety evaluation of MWCNTs.

[Effects of length and chemical modification on the activation of vascular endothelial cells induced by multi walled carbon nanotubes]

OBJECTIVE

To investigate the effects of multi-walled carbon nanotubes (MWCNTs) with different length or chemical modification on endothelial cell activation and to explore the role of nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome.

METHODS

MWCNTs were characterized by dynamic light scattering (DLS) after being suspended in culture medium. The immortalized mouse cerebral microvascular endothelial cell line b.End3 was treated with short MWCNTs (S-MWCNT, 0.5 to 2 μm), long MWCNTs (L-MWCNT, 10 to 30 μm) and the above long MWCNTs functionalized by carboxyl-(L-MWCNT-COOH), amino-(L-MWCNT-NH2) or hydroxyl-(L-MWCNT-OH) modification. Cytotoxicity of MWCNTs in b.End3 cells was determined by cell counting kit-8 (CCK-8) assay and lactate dehydrogenase (LDH) release assay, and non-toxic low dose was selected for subsequent experiments. Effects of all types of MWCNTs on the endothelial activation of b.End3 were determined by the measurement of vascular cell adhesion molecule-1 (VCAM-1) concentration in cell supernatant and adhesion assay of human monocytic cell line THP-1 to b.End3.To further elucidate the mechanism involved, the protein expressions of nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3(NLRP3) in cells treated with S-MWCNT, L-MWCNT and L-MWCNT-COOH were measured by Western blot.

RESULTS

At a higher concentration (125 μg/cm2) and treated for 24 h, all types of MWCNTs significantly inhibited viability of b.End3 cells. At a sub-toxic concentration (6.25 μg/cm2), all types of MWCNTs treated for 12 h significantly induced the activation of b.End3 cells, as evidenced by the elevated VCAM-1 release and THP-1 adhesion. Compared with S-MWCNT, L-MWCNT significantly promoted endothelial cell activation. L-MWCNT and L-MWCNT-COOH activated b.End3 cells to a similar extent. Furthermore, treatment with S-MWCNT, L-MWCNT and L-MWCNT-COOH increased NLRP3 expression in a time-dependent manner at 6.25 μg/cm2. Compared with S-MWCNT, cells treated with L-MWCNT for 4 h and 12 h exhibited significantly increased protein expressions of NLRP3. However, no significant differences were detected in the level of NLRP3 protein in cells treated with L-MWCNT and L-MWCNT-COOH.

CONCLUSION

Compared with the surface chemical modification, length changes of MWCNTs exerted more influence on endothelial cell activation, which may be related to the activation of NLRP3 inflammasome. Our study contributes further understanding of the impact of MWCNTs on endothelial cells, which may have implications for the improvement of safety evaluation of MWCNTs.

An update on the regulatory mechanisms of NLRP3 inflammasome activation

The NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome is a multiprotein complex involved in the release of mature interleukin-1β and triggering of pyroptosis, which is of paramount importance in a variety of physiological and pathological conditions. Over the past decade, considerable advances have been made in elucidating the molecular mechanisms underlying the priming/licensing (Signal 1) and assembly (Signal 2) involved in NLRP3 inflammasome activation. Recently, a number of studies have indicated that the priming/licensing step is regulated by complicated mechanisms at both the transcriptional and posttranslational levels. In this review, we discuss the current understanding of the mechanistic details of NLRP3 inflammasome activation with a particular emphasis on protein-protein interactions, posttranslational modifications, and spatiotemporal regulation of the NLRP3 inflammasome machinery. We also present a detailed summary of multiple positive and/or negative regulatory pathways providing upstream signals that culminate in NLRP3 inflammasome complex assembly. A better understanding of the molecular mechanisms underlying NLRP3 inflammasome activation will provide opportunities for the development of methods for the prevention and treatment of NLRP3 inflammasome-related diseases.

Combined In Vitro and In Vivo Approaches to Propose a Putative Adverse Outcome Pathway for Acute Lung Inflammation Induced by Nanoparticles: A Study on Carbon Dots

With the growth of nanotechnologies, concerns raised regarding the potential adverse effects of nanoparticles (NPs), especially on the respiratory tract. Adverse outcome pathways (AOP) have become recently the subject of intensive studies in order to get a better understanding of the mechanisms of NP toxicity, and hence hopefully predict the health risks associated with NP exposure. Herein, we propose a putative AOP for the lung toxicity of NPs using emerging nanomaterials called carbon dots (CDs), and in vivo and in vitro experimental approaches. We first investigated the effect of a single administration of CDs on mouse airways. We showed that CDs induce an acute lung inflammation and identified airway macrophages as target cells of CDs. Then, we studied the cellular responses induced by CDs in an in vitro model of macrophages. We observed that CDs are internalized by these cells (molecular initial event) and induce a series of key events, including loss of lysosomal integrity and mitochondrial disruption (organelle responses), as well as oxidative stress, inflammasome activation, inflammatory cytokine upregulation and macrophage death (cellular responses). All these effects triggering lung inflammation as tissular response may lead to acute lung injury.

Review on Carbon Nanotube Varieties for Healthcare Application: Effect of Preparation Methods and Mechanism Insight

Many potential uses of carbon nanotubes (CNT) in various sectors have created an urge to assess their diverse range of properties pertaining to various applications like catalysis, biosensor, and antimicrobial activity. Increasing studies on the biosensor and antibacterial activity of CNT have prompted tremendous interest in the utilization of the carbon-based nanostructured material as an alternative to currently existing antibiotics. However, the study of bactericidal aspects of this nanomaterial is relatively new and hence the deeper understanding of the various physicochemical characteristics and antimicrobial nature of CNT is extremely wanted. This review covers the effect of framework substitution and explains the understanding of membrane disintegration and oxidative stresses upon nanomaterials for antimicrobial activity. The present article has also reviewed effect of preparation nanoparticle deposition and framework modification on carbon nanotube structure. The recent research on graphene-modified nanomaterials for biosensor applications related to healthcare/clinical applications have also been discussed. Major physicochemical contributing factors such as size, functionalization, high surface area, and aggregation features of CNT assisting in the bacterial killing have nicely been outlined. Hence, the present review explains the supporting information related with Single and multi-walled carbon nanotube and summarized the advantages of functionalized carbon nanotube/graphene-based nanostructured carbon-based materials towards protection and reduction of bacterial/viral infections in the healthcare sector.

2D materials in electrochemical sensors for in vitro or in vivo use

Individual cells and cell populations are at the present time investigated with a myriad of analytical tools. While most of them are commercially available, some of these analytical tools are just emerging from research laboratories and are in the developmental phase. Electrochemical sensors which allow the monitoring of low molecular weight compounds released (and / or uptaken) by cells are among these emerging tools. Such sensors are increasingly built using 2D materials (e.g. graphene-based materials, transition metal dichalcogenides, etc.) with the aim of conferring better analytical performances to these devices. The present work critically reviews studies published during the last 10 years describing electrochemical sensors made with 2D materials and exploited to monitor small compounds (e.g. H₂O₂, ·NO, glucose, etc.) in living biological systems. It also discusses the very few 2D material-based electrochemical sensors which are wearable or usable in vivo. Finally, the present work includes a specific section about 2D material biocompatibility, a fundamental requirement for 2D material-based sensor applications in vitro and in vivo. As such, the review provides a critical view on the state of the art of electrochemical sensors made with 2D materials and used at cellular level and it evaluates the possibility that such sensors will be used on / in the human body on a wider scale.

Scalable Fabrication of Modified Graphene Nanoplatelets as an Effective Additive for Engine Lubricant Oil

The use of nano-additives is widely recognized as a cheap and effective pathway to improve the performance of lubrication by minimizing the energy loss from friction and wear, especially in diesel engines. In this work, a simple and scalable protocol was proposed to fabricate a graphene additive to improve the engine lubricant oil. Graphene nanoplates (GNPs) were obtained by a one-step chemical exfoliation of natural graphite and were successfully modified with a surfactant and an organic compound to obtain a modified GNP additive, that can be facilely dispersed in lubricant oil. The GNPs and modified GNP additive were characterized using scanning electron microscopy, X-ray diffraction, atomic force microscopy, Raman spectroscopy, and Fourier-transform infrared spectroscopy. The prepared GNPs had wrinkled and crumpled structures with a diameter of 10–30 µm and a thickness of less than 15 nm. After modification, the GNP surfaces were uniformly covered with the organic compound. The addition of the modified GNP additive to the engine lubricant oil significantly enhanced the friction and antiwear performance. The highest reduction of 35% was determined for the wear scar diameter with a GNP additive concentration of approximately 0.05%. The mechanism for lubrication enhancement by graphene additives was also briefly discussed.