Self-replicating murine ex vivo cultured alveolar macrophages as a model for toxicological studies of particle-induced inflammation.

Alveolar macrophages (AM) are integral to maintaining homeostasis within the lungs following exposure to inhaled particles. However, due to the high animal number requirements for in vitro research with primary AM, there remains a need for validated cell models that replicate alveolar macrophages in form and function to better understand the mechanisms that contribute to particle-induced inflammation and disease. A novel, easily adaptable, culture model that facilitates the continued expansion of murine alveolar macrophages for several months, termed murine ex vivo cultured AM (mexAM) has been recently described.

Hyperspectral microscopy of subcutaneously released silver nanoparticles reveals sex differences in drug distribution.

Biomaterials have a great potential to improve human health, however in vitro and in vivo studies are necessary to provide information on their efficacy and safety. This study reports on a comprehensive evaluation of core-shell electrospun fibers loaded with silver nanoparticles (Ag NP) where the delivery rate was controlled by different sizes of Ag NP and thermoresponsive poly(n-isopropylacrylamide) (PNIPAM) hydrogel particles. Fiber meshes also contain zinc oxide nanoparticles (ZnO NP), to improve pore structure for controlled release of Ag NP.

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.

Respiratory and systemic impacts following MWCNT inhalation in B6C3F1/N mice.

Background: A very pure multi-walled carbon nanotube (MWCNT) that was shown to have very low toxicity in vitro, was evaluated for lung and systemic effects and distribution following inhalation exposure.

Methods: B6C3F1/N mice were exposed to varying doses (0, 0.06, 0.

Therapeutic treatment of dietary docosahexaenoic acid for particle-induced pulmonary inflammation in Balb/c mice.

Objective And Design: The omega-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) has been reported to suppress inflammation. Pulmonary inflammation can be directly linked to exposure of various occupational and man-made particles leading to pulmonary diseases. Therapeutic treatments are lacking for particle-induced pulmonary inflammation.

Docosahexaenoic acid impacts macrophage phenotype subsets and phagolysosomal membrane permeability with particle exposure.

Inhalation of particles results in pulmonary inflammation; however, treatments are currently lacking. Docosahexaenoic acid (DHA) is an omega-3 polyunsaturated fatty acid shown to exhibit anti-inflammatory capabilities. The impact of DHA on particle-induced inflammation is unclear; therefore, the aim of this study was to examine the hypothesis that DHA downregulates macrophage inflammatory responses by altering phagolysosomal membrane permeability (LMP) and shifting macrophage phenotype.

Mouse pulmonary dose- and time course-responses induced by exposure to nitrogen-doped multi-walled carbon nanotubes.

In this study, we compared and bioactivity of nitrogen-doped multi-walled carbon nanotubes (NDMWCNT) to MWCNT to test the hypothesis that nitrogen doping would alter bioactivity. High-resolution transmission electron microscopy (TEM) confirmed the multilayer structure of MWCNT with an average layer distance of 0.36 nm, which was not altered by nitrogen doping: the nanomaterials had similar widths and lengths.

Multiwalled Carbon Nanotubes of Varying Size Lead to DNA Methylation Changes That Correspond to Lung Inflammation and Injury in a Mouse Model.

Diversity in physicochemical properties of engineered multiwalled carbon nanotubes (MWCNTs) increases the complexity involved in interpreting toxicity studies of these materials. Studies indicate that epigenetic changes could be at least partially involved in MWCNTs-induced pro-inflammatory and fibrotic lung pathology. Therefore, we examined distinct methylation changes in response to MWCNTs of varied sizes to identify potential epigenetic biomarkers of MWCNTs exposure and disease progression.

Lung deposition patterns of MWCNT vary with degree of carboxylation.

Functionalization of multi-walled carbon nanotubes (MWCNT) is known to affect the biological response (e.g. toxicity, inflammation) in vitro and in vivo.

Modification of nano-silver bioactivity by adsorption on carbon nanotubes and graphene oxide.

Objective: The toxicity of silver nanomaterials in various forms has been extensively evaluated, but the toxicity of silver nanocarbon composites is less well understood. Therefore, silver-carbon nanotube composites (Ag-MWCNT-COOH) and silver-graphene oxide composites (Ag-GO) were synthesized by microwave irradiation and evaluated in two in vitro cell models.

Materials/methods: Toxicity of silver nanosphere (Ag), Ag-MWCNT-COOH and Ag-GO were analyzed by MTS assay and LDH assay in primary C57BL/6 murine alveolar macrophages and human THP-1 cells.

Effect of Carbon Nanotube-Metal Hybrid Particle Exposure to Freshwater Algae Chlamydomonas reinhardtii.

We demonstrate for the first time the toxicity of carbon nanotube (CNT) metal hybrids on freshwater algae. Carbon nanotube-silver (CNT-Ag) and platinum hybrids (CNT-Pt) were synthesized and exposed to Chlamydomonas reinhardtii (C. reinhardtii), and their toxicity was compared to the pure metal salts.

The Effects of Varying Degree of MWCNT Carboxylation on Bioactivity in Various In Vivo and In Vitro Exposure Models.

Functionalization has been shown to alter toxicity of multi-walled carbon nanotube (MWCNT) in several studies. This study varied the degree of functionalization (viz., amount of MWCNT surface carboxylation) to define the relationship between the extent of carboxylation and effects in a variety of in vitro cell models and short-term ex vivo/in vivo particle exposures.

Perinatal exposure to environmental tobacco smoke is associated with changes in DNA methylation that precede the adult onset of lung disease in a mouse model.

Prenatal and early-life environmental tobacco smoke (ETS) exposure can induce epigenetic alterations associated with inflammation and respiratory disease. The objective of this study was to address the long-term epigenetic consequences of perinatal ETS exposure on latent respiratory disease risk, which are still largely unknown. C57BL/6 mice were exposed to prenatal and early-life ETS; offspring lung pathology, global DNA, and gene-specific methylation were measured at two adult ages.

Length, but Not Reactive Edges, of Cup-stack MWCNT Is Responsible for Toxicity and Acute Lung Inflammation.

Multiwalled carbon nanotube (MWCNT) toxicity after inhalation has been associated with size, aspect ratio, rigidity, surface modification, and reactive oxygen species production. In this study, we investigated a series of cup-stacked MWCNT prepared as variants of the Creos 24PS. Mechanical chopping produced a short version (AR10) and graphitization to remove active reaction sites by extreme heat (2,800°C; Creos 24HT) to test the contribution of length and alteration of potential reaction sites to toxicity.

Engineered nanomaterial-induced lysosomal membrane permeabilization and anti-cathepsin agents.

Engineered nanomaterials (ENMs), or small anthropogenic particles approximately < 100 nm in size and of various shapes and compositions, are increasingly incorporated into commercial products and used for industrial and medical purposes. There is an exposure risk to both the population at large and individuals in the workplace with inhalation exposures to ENMs being a primary concern. Further, there is increasing evidence to suggest that certain ENMs may represent a significant health risk, and many of these ENMs exhibit distinct similarities with other particles and fibers that are known to induce adverse health effects, such as asbestos, silica, and particulate matter (PM).

Phagolysosome acidification is required for silica and engineered nanoparticle-induced lysosome membrane permeabilization and resultant NLRP3 inflammasome activity.

NLRP3 inflammasome activation occurs in response to hazardous particle exposures and is critical for the development of particle-induced lung disease. Mechanisms of Lysosome Membrane Permeabilization (LMP), a central pathway for activation of the NLRP3 inflammasome by inhaled particles, are not fully understood. We demonstrate that the lysosomal vATPases inhibitor Bafilomycin A1 blocked LMP in vitro and ex vivo in primary murine macrophages following exposure to silica, multi-walled carbon nanotubes, and titanium nanobelts.

Autophagy deficiency in macrophages enhances NLRP3 inflammasome activity and chronic lung disease following silica exposure.

Autophagy is an important metabolic mechanism that can promote cellular survival following injury. The specific contribution of autophagy to silica-induced inflammation and disease is not known. The objective of these studies was to determine the effects of silica exposure on the autophagic pathway in macrophages, as well as the general contribution of autophagy in macrophages to inflammation and disease.

The Association of LINE-1 Hypomethylation with Age and Centromere Positive Micronuclei in Human Lymphocytes.

Global hypomethylation in white blood cell (WBC) DNA has recently been proposed as a potential biomarker for determining cancer risk through genomic instability. However, the amplitude of the changes associated with age and the impacts of environmental factors on DNA methylation are unclear. In this study, we investigated the association of genomic hypomethylation with age, cigarette use, drinking status and the presence of centromere positive micronuclei (MNC+)-a biomarker for age-dependent genomic instability.

Synthesis, characterization, and bioactivity of carboxylic acid-functionalized titanium dioxide nanobelts.

Background: Surface modification strategies to reduce engineered nanomaterial (ENM) bioactivity have been used successfully in carbon nanotubes. This study examined the toxicity and inflammatory potential for two surface modifications (humic acid and carboxylation) on titanium nanobelts (TNB).

Methods: The in vitro exposure models include C57BL/6 alveolar macrophages (AM) and transformed human THP-1 cells exposed to TNB for 24 hrs in culture.

Role of lysosomes in silica-induced inflammasome activation and inflammation in absence of MARCO.

MARCO is the predominant scavenger receptor for recognition and binding of silica particles by alveolar macrophages (AM). Previously, it was shown that mice null for MARCO have a greater inflammatory response to silica, but the mechanism was not described. The aim of this study was to determine the relationship between MARCO and NLRP3 inflammasome activity.

The effect of size on Ag nanosphere toxicity in macrophage cell models and lung epithelial cell lines is dependent on particle dissolution.

Silver (Ag) nanomaterials are increasingly used in a variety of commercial applications. This study examined the effect of size (20 and 110 nm) and surface stabilization (citrate and PVP coatings) on toxicity, particle uptake and NLRP3 inflammasome activation in a variety of macrophage and epithelial cell lines. The results indicated that smaller Ag (20 nm), regardless of coating, were more toxic in both cell types and most active in the THP-1 macrophages.

Effect of MWCNT size, carboxylation, and purification on in vitro and in vivo toxicity, inflammation and lung pathology.

Background: Several properties of multi-walled carbon nanotubes (MWCNT) have the potential to affect their bioactivity. This study examined the in vitro and in vivo outcomes of the influence of diameter, length, purification and carboxylation (in vitro testing only) of MWCNT.

Methods: Three original 'as received' MWCNT that varied in size (diameter and length) were purified and functionalized by carboxylation.

Three human cell types respond to multi-walled carbon nanotubes and titanium dioxide nanobelts with cell-specific transcriptomic and proteomic expression patterns.

The growing use of engineered nanoparticles (NPs) in commercial and medical applications raises the urgent need for tools that can predict NP toxicity. Global transcriptome and proteome analyses were conducted on three human cell types, exposed to two high aspect ratio NP types, to identify patterns of expression that might indicate high versus low NP toxicity. Three cell types representing the most common routes of human exposure to NPs, including macrophage-like (THP-1), small airway epithelial and intestinal (Caco-2/HT29-MTX) cells, were exposed to TiO2 nanobelts (TiO2-NB; high toxicity) and multi-walled carbon nanotubes (MWCNT; low toxicity) at low (10 µg/mL) and high (100 µg/mL) concentrations for 1 and 24 h.

Interlaboratory evaluation of in vitro cytotoxicity and inflammatory responses to engineered nanomaterials: the NIEHS Nano GO Consortium.

Background: Differences in interlaboratory research protocols contribute to the conflicting data in the literature regarding engineered nanomaterial (ENM) bioactivity.

Objectives: Grantees of a National Institute of Health Sciences (NIEHS)-funded consortium program performed two phases of in vitro testing with selected ENMs in an effort to identify and minimize sources of variability.

Methods: Consortium program participants (CPPs) conducted ENM bioactivity evaluations on zinc oxide (ZnO), three forms of titanium dioxide (TiO2), and three forms of multiwalled carbon nanotubes (MWCNTs).

Purification and sidewall functionalization of multiwalled carbon nanotubes and resulting bioactivity in two macrophage models.

This study examined the consequences of surface carboxylation of multiwalled carbon nanotubes (MWCNT) on bioactivity. Since commercial raw MWCNT contain impurities that may affect their bioactivity, HCl refluxing was exploited to purify raw "as-received" MWCNT by removing the amorphous carbon layer on the MWCNT surface and reducing the metal impurities (e.g.