Drug delivery by polymeric nanoparticles induces autophagy in macrophages

Beyond the polysaccharide and glycoconjugate vaccines for Streptococcus pneumoniae: Does protein/peptide nanovaccines hold promises?

Streptococcus pneumoniae having almost 98 serotypes and being common cause of acute otitis media, pneumonia, bacteremia, meningitis etc., which results in high mortality and morbidity globally. Although vaccines like PCV-13 and PPV-23 are available, some problems like serotype replacement and poor immunogenicity in children, old age and immunocompromised people has been observed. To overcome these drawbacks protein/peptide-based vaccine can be a good strategy as these provides wide serotype coverage. However, immunogenicity of protein subunit vaccines is lower, that issue can be solved by using adjuvants. Recently nanoparticles as an adjuvant for vaccine delivery being used, which has provided not only good immunogenicity but also improved delivery and efficiency of protein-based vaccines. In this review we have discussed the latest advancement of nanoparticles-based protein/peptide vaccine delivery for Streptococcus pneumoniae.

Autophagy-induced intracellular signaling fractional nano-drug system for synergistic anti-tumor therapy

Autophagy inducers increase the sensitivity of tumor cells to chemotherapeutic drugs and enhance anti-tumor efficacy. An autophagy-induced intracellular signaling fractional nano-drug system was constructed for the co-delivery of the autophagy inducer rapamycin (RAPA) and the anti-tumor drug 9-nitro-20(S)-camptothecin (9-NC). Link peptides, including cathepsin B-sensitive peptides (Ala-Leu-Ala-Leu, ALAL), nucleus-targeting peptides (TAT, sequence: YGRKKRRQRRR), and chrysin (CHR)-modified hydrophobic biodegradable polymers (poly(-caprolactone)) (PCL), were grafted onto hyaluronic acid (HA) to yield two amphiphiles, HA-ALAL-PCL-CHR (CPAH) and HA-ALAL-TAT-PCL-CHR (CPTAH). Spherical RAPA- and 9-NC-loaded micelles were obtained by the self-assembly of amphiphiles comprising CPAH and RAPA and CPTAH and 9-NC. In this fractional nano-drug system, RAPA was released earlier than 9-NC, as CPAH as a RAPA carrier lacked a nucleus-targeting TAT (unlike CPTAH as an 9-NC carrier). RAPA induced autophagy in tumor cells and improved their sensitivity, whereas the secondary nucleus-targeting micelles directly delivered 9-NC to the nucleus, considerably improving anti-tumor efficacy. Immunofluorescence staining, acridine orange (AO) staining, and western blotting results demonstrated that the system induced a high level of autophagy in combination chemotherapy. The proposed system possesses a high level of cytotoxicity in vitro and in vivo and provides a potential method for enhancing anti-tumor efficacy in clinical settings.

Methotrexate conjugated gold nanoparticles improve rheumatoid vascular dysfunction in rat adjuvant-induced arthritis: gold revival

Endothelial vasomotor dysfunction and accelerated atherosclerosis encompass the features of rheumatoid vascular dysfunction (RVD), increasing cardiovascular morbidity and mortality among rheumatoid arthritis (RA) patients. Methotrexate, among DMARDs, effectively reduces cardiovascular events, but its non-selectivity together with its pharmacokinetic variability often limit drug adherence and contribute to its potential toxicity. Thus, methotrexate was conjugated to gold nanoparticles (MTX/AuNPs) and its effect on RVD in rats' adjuvant-induced arthritis was evaluated. A comparative study between MTX/AuNPs, free MTX, and AuNPs treatments on joint inflammation, vascular reactivity and architecture, smooth muscle phenotype, systemic inflammation, and atherogenic profile was done. Since MTX/AuNPs effect was superior, it appears that conjugation of MTX to AuNPs demonstrated a synergistic action. MTX immunomodulatory action combined with AuNPs anti-atherogenic potential yielded prompt control of whole features of RVD. These findings highlight the usefulness of nanoparticles-targeted drug-delivery system in refining rheumatoid-induced vascular dysfunction treatment and reviving gold use in RA.

Nanomaterials targeting macrophages in sepsis: A promising approach for sepsis management

Sepsis is a life-threatening organ dysfunction resulting from dysregulated host responses to infection. Macrophages play significant roles in host against pathogens and the immunopathogenesis of sepsis, such as phagocytosis of pathogens, secretion of cytokines, and phenotype reprogramming. However, the rapid progression of sepsis impairs macrophage function, and conventional antimicrobial and supportive treatment are not sufficient to restore dysregulated macrophages roles. Nanoparticles own unique physicochemical properties, surface functions, localized surface plasmon resonance phenomenon, passive targeting in vivo, good biocompatibility and biodegradability, are accessible for biomedical applications. Once into the body, NPs are recognized by host immune system. Macrophages are phagocytes in innate immunity dedicated to the recognition of foreign substances, including nanoparticles, with which an immune response subsequently occurs. Various design strategies, such as surface functionalization, have been implemented to manipulate the recognition of nanoparticles by monocytes/macrophages, and engulfed by them to regulate their function in sepsis, compensating for the shortcomings of sepsis traditional methods. The review summarizes the mechanism of nanomaterials targeting macrophages and recent advances in nanomedicine targeting macrophages in sepsis, which provides good insight for exploring macrophage-based nano-management in sepsis.

Nanotherapeutics in autophagy: a paradigm shift in cancer treatment

Autophagy is a catabolic process in which an organism responds to its nutrient or metabolic emergencies. It involves the degradation of cytoplasmic proteins and organelles by forming double-membrane vesicles called "autophagosomes." They sequester cargoes, leading them to degradation in the lysosomes. Although autophagy acts as a protective mechanism for maintaining homeostasis through cellular recycling, it is ostensibly a cause of certain cancers, but a cure for others. In other words, insufficient autophagy, due to genetic or cellular dysfunctions, can lead to tumorigenesis. However, many autophagy modulators are developed for cancer therapy. Diverse nanoparticles have been documented to induce autophagy. Also, the highly stable nanoparticles show blockage to autophagic flux. In this review, we revealed a general mechanism by which autophagy can be induced or blocked via nanoparticles as well as several studies recently performed to prove the stated fact. In addition, we have also elucidated the paradoxical roles of autophagy in cancer and how their differential role at different stages of various cancers can affect its treatment outcomes. And finally, we summarize the breakthroughs in cancer disease treatments by using metallic, polymeric, and liposomal nanoparticles as potent autophagy modulators.

Vaccines platforms and COVID-19: what you need to know

BACKGROUND

The novel SARS-CoV-2, responsible for the COVID-19 pandemic, is the third zoonotic coronavirus since the beginning of the 21 first century, and it has taken more than 6 million human lives because of the lack of immunity causing global economic losses. Consequently, developing a vaccine against the virus represents the fastest way to finish the threat and regain some "normality."

OBJECTIVE

Here, we provide information about the main features of the most important vaccine platforms, some of them already approved, to clear common doubts fostered by widespread misinformation and to reassure the public of the safety of the vaccination process and the different alternatives presented.

METHODS

Articles published in open access databases until January 2022 were identified using the search terms "SARS-CoV-2," "COVID-19," "Coronavirus," "COVID-19 Vaccines," "Pandemic," COVID-19, and LMICs or their combinations.

DISCUSSION

Traditional first-generation vaccine platforms, such as whole virus vaccines (live attenuated and inactivated virus vaccines), as well as second-generation vaccines, like protein-based vaccines (subunit and viral vector vaccines), and third-generation vaccines, such as nanoparticle and genetic vaccines (mRNA vaccines), are described.

CONCLUSIONS

SARS-CoV-2 sequence information obtained in a record time provided the basis for the fast development of a COVID-19 vaccine. The adaptability characteristic of the new generation of vaccines is changing our capability to react to emerging threats to future pandemics. Nevertheless, the slow and unfair distribution of vaccines to low- and middle-income countries and the spread of misinformation are a menace to global health since the unvaccinated will increase the chances for resurgences and the surge of new variants that can escape the current vaccines.

In Vitro Molecular Study of Titanium-Niobium Alloy Biocompatibility

Titanium dental implants have common clinical applications due to their biocompatibility, biophysical and biochemical characteristics. Although current titanium is thought to be safe and beneficial for patients, there are several indications that it may release toxic metal ions or metal nanoparticles from its alloys into the surrounding environment, which could lead to clinically relevant complications including toxic reactions as well as immune dysfunctions. Hence, an adequate selection and testing of medical biomaterial with outstanding properties are warranted. This study was designed to explore the biocompatibility of smooth titanium-niobium alloy (S_TiNb) versus smooth titanium commercially pure (S_TiCp)—a reference in implantology. All experiments were performed in vitro using human osteoblast-like SaOs-2 and monocyte THP-1 cell lines as models. Cell adhesion and growth morphology were determined by scanning electron microscopy, while cell viability was evaluated using WST-1 assay. Because niobate anions or niobium nanoparticles can be released from implants during biomaterial-cell interaction, potential immunotoxicity of potassium niobate (KNbO₃₎ salt was evaluated by examining both metabolic activity and transcriptomic profiling of treated THP-1 monocytes. The main findings of this study are that S_TiCp and S_TiNb discs do not show an impact on the proliferation and viability of SaOs-2 cells compared to polystyrene surfaces, whereas a significant decrease in THP-1 cells’ viability and metabolic activity was observed in the presence of S_TiNb discs compared to the control group. However, no significant changes were found neither at the metabolic activity nor at the transcriptomic level of THP-1 monocytes exposed to KNbO₃ salt, suggesting that niobium has no effect on the immune system. Overall, these data imply a possible toxicity of S_TiNb discs toward THP-1 cells, which may not be directly related to niobium but perhaps to the manufacturing process of titanium-niobium alloy. Thus, this limitation must be overcome to make titanium alloy an excellent material for medical applications.

Design and Evaluation of Autophagy-Inducing Particles for the Treatment of Abnormal Lipid Accumulation

Autophagy is a fundamental housekeeping process by which cells degrade their components to maintain homeostasis. Defects in autophagy have been associated with aging, neurodegeneration and metabolic diseases. Non-alcoholic fatty liver diseases (NAFLDs) are characterized by hepatic fat accumulation with or without inflammation. No treatment for NAFLDs is currently available, but autophagy induction has been proposed as a promising therapeutic strategy. Here, we aimed to design autophagy-inducing particles, using the autophagy-inducing peptide (Tat-Beclin), and achieve liver targeting in vivo, taking NAFLD as a model disease. Polylactic acid (PLA) particles were prepared by nanoprecipitation without any surfactant, followed by surface peptide adsorption. The ability of Tat-Beclin nanoparticles (NP T-B) to modulate autophagy and to decrease intracellular lipid was evaluated in vitro by LC3 immunoblot and using a cellular model of steatosis, respectively. The intracellular localization of particles was evaluated by transmission electron microscopy (TEM). Finally, biodistribution of fluorescent NP T-B was evaluated in vivo using tomography in normal and obese mice. The results showed that NP T-B induce autophagy with a long-lasting and enhanced effect compared to the soluble peptide, and at a ten times lower dose. Intracellular lipid also decreased in a cellular model of NAFLD after treatment with T-B and NP T-B under the same dose conditions. Ultrastructural studies revealed that NP T-B are internalized and located in endosomal, endolysosomal and autolysosomal compartments, while in healthy and obese mice, NP T-B could accumulate for several days in the liver. Given the beneficial effects of autophagy-inducing particles in vitro, and their capacity to target the liver of normal and obese mice, NP T-B could be a promising therapeutic tool for NAFLDs, warranting further in vivo investigation.

Polymeric nanoparticles in the diagnosis and treatment of myocardial infarction: Challenges and future prospects

Myocardial infarction (MI) is the leading cause of morbidity and mortality worldwide. Despite extensive efforts to provide early diagnosis and adequate treatment regimens, detection of MI still faces major limitations and pathological MI complications continue to threaten the recovery of survivors. Polymeric nanoparticles (NPs) represent novel noninvasive drug delivery systems for the diagnosis and treatment of MI and subsequent prevention of fatal heart failure. In this review, we cover the recent advances in polymeric NP-based diagnostic and therapeutic approaches for MI and their application as multifunctional theranostic tools. We also discuss the in vivo behavior and toxicity profile of polymeric NPs, their application in noninvasive imaging, passive, and active drug delivery, and use in cardiac regenerative therapy. We conclude with the challenges faced with polymeric nanosystems and suggest future efforts needed for clinical translation.

Recent Advancements in Hyperthermia-Driven Controlled Drug Delivery from Nanotherapeutics

Previous reviews of the works on magnetic nanoparticles for hyperthermia-induced treatment concentrated mostly on magnetic fluid hyperthermia (MFH) employing monometallic/metal oxide nanocomposites. In the literature, the word "hyperthermia" was also limited to the use of heat for medicinal purposes. A number of articles have recently been published demonstrating that magnetic nanoparticle-based hyperthermia may produce restricted high temperatures, resulting in the release of medicines that are either connected to the magnetic nanoparticles or encased in polymer matrices. In this debate, we propose broadening the concept of "hyperthermia" to encompass temperature-based treatment as well as magnetically controlled medication delivery. The review also addresses core-shell magnetic nanomaterials, particularly nanoshells made by stacked assembly, for the use of hyperthermia- based treatment and precise administration of drugs. The primary objective of this review article is to demonstrate how the combination of hyperthermia-induced therapy and on-demand' drug release models may lead to effective applications in personalized medicine.

Assessment of changes in autophagic vesicles in human immune cell lines exposed to nano particles

Background

Safe and rational development of nanomaterials for clinical translation requires the assessment of potential biocompatibility. Autophagy, a critical homeostatic pathway intrinsically linked to cellular health and inflammation, has been shown to be affected by nanomaterials. It is, therefore, important to be able to assess possible interactions of nanomaterials with autophagic processes.

Results

CEM (T cell), Raji (B lymphocyte), and THP-1 (human monocyte) cell lines were subject to treatment with rapamycin and chloroquine, known to affect the autophagic process, in order to evaluate cell line-specific responses. Flow cytometric quantification of a fluorescent autophagic vacuole stain showed that maximum observable effects (105%, 446%, and 149% of negative controls) were achieved at different exposure durations (8, 6, and 24 h for CEM, Raji, and THP-1, respectively). THP-1 was subsequently utilised as a model to assess the autophagic impact of a small library of nanomaterials. Association was observed between hydrodynamic size and autophagic impact (r² = 0.11, p = 0.004). An ELISA for p62 confirmed the greatest impact by 10 nm silver nanoparticles, abolishing p62, with 50 nm silica and 180 nm polystyrene also lowering p62 to a significant degree (50%, 74%, and 55%, respectively, p < 0.05).

Conclusions

This data further supports the potential for a variety of nanomaterials to interfere with autophagic processes which, in turn, may result in altered cellular function and viability. The association of particle size with impact on autophagy now warrants further investigation.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-021-00648-8.

The Macrophage Response to Mycobacterium tuberculosis and Opportunities for Autophagy Inducing Nanomedicines for Tuberculosis Therapy

The major causative agent of tuberculosis (TB), i.e., Mycobacterium tuberculosis (Mtb), has developed mechanisms to evade host defense responses and persist within host cells for prolonged periods of time. Mtb is also increasingly resistant to existing anti-TB drugs. There is therefore an urgent need to develop new therapeutics for TB and host directed therapies (HDTs) hold potential as effective therapeutics for TB. There is growing interest in the induction of autophagy in Mtb host cells using autophagy inducing compounds (AICs). Nanoparticles (NPs) can enhance the effect of AICs, thus improving stability, enabling cell targeting and providing opportunities for multimodal therapy. In this review, we focus on the macrophage responses to Mtb infection, in particular, the mechanistic aspects of autophagy and the evasion of autophagy by intracellular Mtb. Due to the overlap between the onset of autophagy and apoptosis; we also focus on the relationship between apoptosis and autophagy. We will also review known AICs in the context of Mtb infection. Finally, we discuss the applications of NPs in inducing autophagy with the intention of sharing insights to encourage further research and development of nanomedicine HDTs for TB therapy.

Toxicity of TiO2 Nanoparticles: Validation of Alternative Models

There are many studies concerning titanium dioxide (TiO2) nanoparticles (NP) toxicity. Nevertheless, there are few publications comparing in vitro and in vivo exposure, and even less comparing air-liquid interface exposure (ALI) with other in vitro and in vivo exposures. The identification and validation of common markers under different exposure conditions are relevant for the development of smart and quick nanotoxicity tests. In this work, cell viability was assessed in vitro by WST-1 and LDH assays after the exposure of NR8383 cells to TiO2 NP sample. To evaluate in vitro gene expression profile, NR8383 cells were exposed to TiO2 NP during 4 h at 3 cm2 of TiO2 NP/cm2 of cells or 19 μg/mL, in two settings-submerged cultures and ALI. For the in vivo study, Fischer 344 rats were exposed by inhalation to a nanostructured aerosol at a concentration of 10 mg/m3, 6 h/day, 5 days/week for 4 weeks. This was followed immediately by gene expression analysis. The results showed a low cytotoxic potential of TiO2 NP on NR8383 cells. Despite the absence of toxicity at the doses studied, the different exposures to TiO2 NP induce 18 common differentially expressed genes (DEG) which are involved in mitosis regulation, cell proliferation and apoptosis and inflammation transport of membrane proteins. Among these genes, we noticed the upregulation of Ccl4, Osm, Ccl7 and Bcl3 genes which could be suggested as early response biomarkers after exposure to TiO2 NP. On the other hand, the comparison of the three models helped us to validate the alternative ones, namely submerged and ALI approaches.

Targeted tumor therapy by autophagy of nanoparticles

Autophagy is an important biological mechanism that regulates the growth, death and energy metabolism of eukaryotic cells. It is also an active and evolutionarily conservative catabolic process to maintain homeostasis during cell stress response and cell survival. Autophagy maintains the body’s stability by degrading damaged proteins, organelles, cytoplasm and invasive microorganisms. Studies have found that autophagy also has a significant impact on the occurrence and development of tumors. Simultaneously, nanoparticles (NPs) can induce autophagy in cells, and the level of autophagy can be regulated by the synthesis design of NPs. Therefore, the study of the regulation of autophagy by NPs is of great significance for the treatment of cancer autocorrelation.

Long Term Pharmacological Perturbation of Autophagy in Mice: Are HCQ Injections a Relevant Choice?

Macroautophagy (hereafter referred to as autophagy) is an evolutionarily conserved catabolic process whose loss-of-function has been linked to a growing list of pathologies. Knockout mouse models of key autophagy genes have been instrumental in the demonstration of the critical functions of autophagy, but they display early lethality, neurotoxicity and unwanted autophagy-independent phenotypes, limiting their applications for in vivo studies. To avoid problems encountered with autophagy-null transgenic mice, we investigated the possibility of disturbing autophagy pharmacologically in the long term. Hydroxychloroquine (HCQ) ip injections were done in juvenile and adult C57bl/6j mice, at range doses adapted from the human malaria prophylactic treatment. The impact on autophagy was assessed by western-blotting, and juvenile neurodevelopment and adult behaviours were evaluated for four months. Quite surprisingly, our results showed that HCQ treatment in conditions used in this study neither impacted autophagy in the long term in several tissues and organs nor altered neurodevelopment, adult behaviour and motor capabilities. Therefore, we recommend for future long-term in vivo studies of autophagy, to use genetic mouse models allowing conditional inhibition of selected Atg genes in appropriate lineage cells instead of HCQ treatment, until it could be successfully revisited using higher HCQ doses and/or frequencies with acceptable toxicity.

Genes expression profiling of alveolar macrophages exposed to non-functionalized, anionic and cationic multi-walled carbon nanotubes shows three different mechanisms of toxicity

Functionalized multi-walled carbon nanotubes (MWCNT) have become the focus of increased research interest, particularly in their application as tools in different areas, such as the biomedical field. Despite the benefits associated with functionalization of MWCNT, particularly in overcoming issues relating to solubility, several studies have demonstrated that these functionalized nanoparticles display different toxicity profiles. For this study, we aim to compare NR8383 cells responses to three well-characterized MWCNT with varying functional groups. This study employed cytotoxicity assays, transcriptomics and proteomics to assess their toxicity using NR8383 rat alveolar macrophages as an in vitro model. The study findings indicated that all MWCNT altered ribosomal protein translation, cytoskeleton arrangement and induced pro-inflammatory response. Only functionalized MWCNT alter mTOR signaling pathway in conjunction with increased Lamtor gene expression. Furthermore, the type of functionalization was also important, with cationic MWCNT activating the transcription factor EB and inducing autophagy while the anionic MWCNT altering eukaryotic translation initiation factor 4 (EIF4) and phosphoprotein 70 ribosomal protein S6 kinase (p70S6K) signaling pathway as well as upregulation Tlr2 gene expression. This study proposes that MWCNT toxicity mechanisms are functionalization dependent and provides evidence that inflammatory response is a key event of carbon nanotubes toxicity.

Nanoparticle-based vaccines

Infectious diseases are the tip of the iceberg in the economic burden of the developing countries, due to the resistance of the pathogens to antibiotics and the lack of vaccines. The vaccines have become a big challenge in the last decades, where the attention has been focused on scientific challenges such as new vaccine development and adjuvants or delivery systems. The classical vaccines were developed from live-attenuated or killed organisms, such as influenza, smallpox, and BCG, as well as subunits such as Hepatitis B. The attenuated vaccines carry the risk of regaining their pathogenicity under immunosuppression conditions. The development of subunit vaccines without risk are considered as an essential need in combination with adequate delivery systems to obtain desired cell and humoral immune responses against infectious diseases. In the last decades, the use of nanoparticles as a delivery system in vaccines has received special attention to improve vaccine efficacy. These nanoparticles could be composed of lipids, metal and nonmetal inorganics, several polymers, and virus-like particles, which have been tested in research; some of them have already been approved for human and animal use. The characteristics of the nanoparticles have allowed targeting desired antigen-presenting cells to improve immunization strategies to induce protection. The main characteristics of the nanoparticles are to protect the antigens from early proteolytic degradation, control antigen release, and help antigen uptake and processing by antigen-presenting cells, and they should be safe for human and veterinary use. In addition, the nanoparticles could be modified in their physicochemical properties to target specific cells and improve vaccine efficacy. This chapter focuses on the nanoparticle-based vaccine formulations and the approaches used to realize efficient delivery of vaccines in order to induce host protective immunity against infectious diseases.

Polyethyleneimine coated Fe3O4 magnetic nanoparticles induce autophagy, NF-κB and TGF-β signaling pathway activation in HeLa cervical carcinoma cells via reactive oxygen species generation

Fe₃O₄ magnetic nanoparticles (MNPs), as one of the most intensively researched NPs, have a range of applications in cancer treatments. In current research, we have focused on the influences of MNPs on cancer cells. We chose polyethyleneimine (PEI) coated MNPs (PEI-MNPs) as a model and they are colloidally stable in biological media. It can be proved that PEI-MNPs result in autophagy induction via mTOR-Akt-p70S6 K and ATG7 signaling pathways. For the first time, we have reported that PEI-MNPs activate both NF-κB and TGF-β signaling, two key pro-inflammatory pathways, in cancer cells. More significantly, we have found that autophagy induction and NF-κB and TGF-β activation can be efficiently suppressed through the inhibition of PEI-MNP dependent reactive oxygen species (ROS) over-production. ROS are deemed as a 'double edge sword' for cancer cells, owing to the cancer-suppressing and cancer-promoting actions. Our findings would be useful for designing MNPs induced ROS anti-cancer strategies or diminishing long-term toxic effects.

Protein and lipid homeostasis altered in rat macrophages after exposure to metallic oxide nanoparticles

Metal oxide nanoparticles (NPs), such as ZnO, ZnFe₂O₄, and Fe₂O₃, are widely used in industry. However, little is known about the cellular pathways involved in their potential toxicity. Here, we particularly investigated the key molecular pathways that are switched on after exposure to sub-toxic doses of ZnO, ZnFe₂O₄, and Fe₂O₃ in the in vitro rat alveolar macrophages (NR8383). As in our model, the calculated IC₅₀ were respectively 16, 68, and more than 200 μg/mL for ZnO, ZnFe₂O₄, and Fe₂O₃; global gene and protein expression profiles were only analyzed after exposure to ZnO and ZnFe₂O₄ NPs. Using a rat genome microarray technology, we found that 985 and 1209 genes were significantly differentially expressed in NR8383 upon 4 h exposure to ¼ IC₅₀ of ZnO and ZnFe₂O₄ NPs, respectively. It is noteworthy that metallothioneins were overexpressed genes following exposure to both NPs. Moreover, Ingenuity Pathway Analysis revealed that the top canonical pathway disturbed in NR8383 exposed to ZnO and ZnFe₂O₄ NPs was eIF2 signaling involved in protein homeostasis. Quantitative mass spectrometry approach performed from both NR8383 cell extracts and culture supernatant indicated that 348 and 795 proteins were differentially expressed upon 24 h exposure to ¼ IC₅₀ of ZnO and ZnFe₂O₄ NPs, respectively. Bioinformatics analysis revealed that the top canonical pathways disturbed in NR8383 were involved in protein homeostasis and cholesterol biosynthesis for both exposure conditions. While VEGF signaling was specific to ZnO exposure, iron homeostasis signaling pathway was specific to ZnFe₂O₄ NPs. Overall, the study provides resource of transcriptional and proteomic markers of response to ZnO and ZnFe₂O₄ NP-induced toxicity through combined transcriptomics, proteomics, and bioinformatics approaches.

Effect of pristine and functionalized multiwalled carbon nanotubes on rat renal cortex

The increasing application of carbon nanotubes (CNTs) within environmental, occupational and consumer settings has raised concerns regarding their biosafety and adverse effects on human health. The present study was designed to investigate the possible adverse effect of pristine and functionalized (amylated and polyethelene glycol coated) multi-walled (MW) CNTs on rat kidney with special concern to the histological alterations and the associated oxidative stress, apoptosis and inflammation. Healthy male albino rats (n = 40) were randomly divided into 4 groups: group I (control), group II (pristine MWCNTs), group III (amylated MWCNTs) and group IV [polyethelene glycol (PEG)-coated MWCNTs]. Animals of groups II, III and IV received a single dose of 1 mg/kg body weight of MWCNTs via intra-tracheal (IT) instillation at the beginning of the experiment and all rats were sacrificed after 30 days. Rats in groups II and III showed, nearly similar, renal tissue damage (evidenced by thin collapsed glomeruli, packed mesangial and endothelial cells as well as edematous hemorrhagic glomeruli with apoptotic changes) and functional disruptions (indicated by high serum levels of urea and creatinine) probably through induction of oxidative stress [revealed by high level of the lipid peroxidation marker malondialdehyde (MDA) and lower levels of the antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx)], apoptosis (indicated by high caspase 3 activity), and inflammation (evidenced by high level of IL1β). However, PEG-coated MWCNTs-treated group (group IV) showed nearly normal renal structure and function. It could be concluded that pristine and functionalized amylated MWCNTs have nephrotoxic effect, while PEG-coated MWCNTs had lowest, or none, toxic effects making them safer for therapy and diagnosis of a variety of diseases.

Cytotoxicity and global transcriptional responses induced by zinc oxide nanoparticles NM 110 in PMA-differentiated THP-1 cells

Despite a wide production and use of zinc oxide nanoparticles (ZnONP), their toxicological study is only of limited number and their impact at a molecular level is seldom addressed. Thus, we have used, as a model, zinc oxide nanoparticle NM110 (ZnO110NP) exposure to PMA-differentiated THP-1 macrophages. The cell viability was studied at the cellular level using WST-1, LDH and Alamar Blue^® assays, as well as at the molecular level by transcriptomic analysis. Exposure of cells to ZnO110NP for 24 h decreased their viability in a dose-dependent manner with mean inhibitory concentrations (IC₅₀) of 8.1 μg/mL. Transcriptomic study of cells exposed to two concentrations of ZnO110NP: IC₅₀ and a quarter of it (IC₅₀/4) for 4 h showed that the expressions of genes involved in metal metabolism are perturbed. In addition, expression of genes acting in transcription regulation and DNA binding, as well as clusters of genes related to protein synthesis and structure were altered. It has to be noted that the expressions of metallothioneins genes (MT1, MT2) and genes of heat-shock proteins genes (HSP) were strongly upregulated for both conditions. These genes might be used as an early marker of exposure to ZnONP. On the contrary, at IC₅₀ exposure, modifications of gene expression involved in inflammation, apoptosis and mitochondrial suffering were noted indicating a less specific cellular response. Overall, this study brings a resource of transcriptional data for ZnONP toxicity for further mechanistic studies.

Crosstalk between Autophagy and Nanomaterials: Internalization, Activation, Termination

Nanomaterials (NMs) are comprehensively applied in biomedicine due to their unique physical and chemical properties. Autophagy, as an evolutionarily conserved cellular quality control process, is closely associated with the effect of NMs on cells. In this review, the recent advances in NM-induced/inhibited autophagy (NM-phagy) are summarized, with an aim to present a comprehensive description of the mechanisms of NM-phagy from the perspective of internalization, activation, and termination, thereby bridging autophagy and nanomaterials. Several possible mechanisms are extensively reviewed including the endocytosis pathway of NMs and the related cross components (clathrin and adaptor protein 2 (AP-2), adenosine diphosphate (ADP)-ribosylation factor 6 (Arf6), Rab, UV radiation resistance associated gene (UVRAG)), three main stress mechanisms (oxidative stress, damaged organelles stress, and toxicity stress), and several signal pathway-related molecules. The mechanistic insight is beneficial to understand the autophagic response to NMs or NMs' regulation of autophagy. The challenges currently encountered and research trend in the field of NM-phagy are also highlighted. It is hoped that the NM-phagy discussion in this review with the focus on the mechanistic aspects may serve as a guideline for future research in this field.

Induction of protein citrullination and auto-antibodies production in murine exposed to nickel nanomaterials

Citrullination, or the post-translational deimination of polypeptide-bound arginine, is involved in several pathological processes in the body, including autoimmunity and tumorigenesis. Recent studies have shown that nanomaterials can trigger protein citrullination, which might constitute a common pathogenic link to disease development. Here we demonstrated auto-antibody production in serum of nanomaterials-treated mice. Citrullination-associated phenomena and PAD levels were found to be elevated in nanomaterials -treated cell lines as well as in the spleen, kidneys and lymph nodes of mice, suggesting a systemic response to nanomaterials injection, and validated in human pleural and pericardial malignant mesothelioma (MM) samples. The observed systemic responses in mice exposed to nanomaterials support the evidence linking exposure to environmental factors with the development of autoimmunity responses and reinforces the need for comprehensive safety screening of nanomaterials. Furthermore, these nanomaterials induce pathological processes that mimic those observed in Pleural MM, and therefore require further investigations into their carcinogenicity.

Autophagy promotes degradation of polyethyleneimine-alginate nanoparticles in endothelial progenitor cells

Polyethyleneimine (PEI)–alginate (Alg) nanoparticle (NP) is a safe and effective vector for delivery of siRNA or DNA. Recent studies suggest that autophagy is related to cytotoxicity of PEI NPs. However, contribution of autophagy to degradation of PEI–Alg NPs remains unknown. CD34⁺VEGFR-3⁺ endothelial progenitor cells isolated from rat bone marrow were treated with 25 kDa branched PEI modified by Alg. After treatment with the NPs, morphological changes and distribution of the NPs in the cells were examined with scanning and transmission electron microscopies. Cytotoxicity of the NPs was analyzed by reactive oxygen species (ROS) production, lactate dehydrogenase leakage and induction of apoptosis. The level of autophagy was assessed with expression of Beclin-1 and LC3 and formation of autophagic structures and amphisomes. Colocalization of LC3-positive puncta and the NPs was determined by LC3–GFP tracing. Cytotoxicity of PEI NPs was reduced greatly after modification with Alg. PEI–Alg NPs were distributed in mitochondria, rough endoplasmic reticula and nuclei as well as cytoplasm. After phagocytosis of the NPs, expression of Beclin-1 mRNA and LC3 protein was upregulated, and the number of LC3-positive puncta, autophagic structures and amphisomes increased significantly. The number of lysosomes also increased obviously. There were LC3-positive puncta in nuclei, and some puncta were colocalized with the NPs. These results demonstrate that the activated autophagy promotes degradation of PEI–Alg NPs via multiple pathways.

Single-cell time-lapse imaging of intracellular O2 in response to metabolic inhibition and mitochondrial cytochrome-c release

The detection of intracellular molecular oxygen (O₂) levels is important for understanding cell physiology, cell death, and drug effects, and has recently been improved with the development of oxygen-sensitive probes that are compatible with live cell time-lapse microscopy. We here provide a protocol for the use of the nanoparticle probe MitoImage-MM2 to monitor intracellular oxygen levels by confocal microscopy under baseline conditions, in response to mitochondrial toxins, and following mitochondrial cytochrome-c release. We demonstrate that the MitoImage-MM2 probe, which embeds Pt(II)-5,10,15,20-tetrakis-(2,3,4,5,6-pentafluorophenyl)-porphyrin as oxygen sensor and poly(9,9-dioctylfluorene) as an O₂-independent component, enables quantitative, ratiometric time-lapse imaging of intracellular O₂. Multiplexing with tetra-methyl-rhodamine-methyl ester in HeLa cervical cancer cells showed significant increases in intracellular O₂ accompanied by strong mitochondrial depolarization when respiratory chain complexes III or IV were inhibited by Antimycin A or sodium azide, respectively, and when cells were maintained at 'physiological' tissue O₂ levels (5% O₂). Multiplexing also allowed us to monitor intracellular O₂ during the apoptotic signaling process of mitochondrial outer membrane permeabilization in HeLa expressing cytochrome-c-eGFP, and demonstrated that mitochondria post cytochrome-c release are able to retain their capacity to respire at physiological O₂ despite a decrease in mitochondrial membrane potential.

Targeted pulmonary delivery of inducers of host macrophage autophagy as a potential host-directed chemotherapy of tuberculosis

One of the promising host-directed chemotherapeutic interventions in tuberculosis (TB) is based on inducing autophagy as an immune effector. Here we consider the strengths and weaknesses of potential autophagy-based pharmacological intervention. Using the existing drugs that induce autophagy is an option, but it has limitations given the broad role of autophagy in most cells, tissues, and organs. Thus, it may be desirable that the agent being used to modulate autophagy is applied in a targeted manner, e.g. delivered to affected tissues, with infected macrophages being an obvious choice. This review addresses the advantages and disadvantages of delivering drugs to induce autophagy in M. tuberculosis-infected macrophages. One option, already being tested in models, is to design particles for inhalation delivery to lung macrophages. The choice of drugs, drug release kinetics and intracellular residence times, non-target cell exposure and feasibility of use by patients is discussed. We term here this (still experimental) approach, of compartment-targeting, autophagy-based, host-directed therapy as "Track-II antituberculosis chemotherapy."

CS/PAA@TPGS/PLGA nanoparticles with intracellular pH-sensitive sequential release for delivering drug to the nucleus of MDR cells

Development of novel nano-drug delivery systems (NDDS) that can transport anticancer drugs into cell nuclei is still a highly desirable strategy for reversing multi-drug resistance (MDR) in cancer therapy. Herein, we designed and prepared a novel NDDS, designated S@L NPs, in which several smaller nanoparticles are contained within a larger nanoparticle. Our S@L NPs (CS/PAA/VP-16@TPGS/PLGA NPs) possess a structure in which smaller nanoparticles (Chitosan-Poly(acrylic acid) nanoparticles, CS/PAA NPs) containing the drug etoposide (VP-16) are loaded within a larger nanoparticle (Vitamin E d-a-tocopheryl polyethylene glycol 1000 succinate-modified poly(lactic-co-glycolic acid) nanoparticles, TPGS/PLGA NPs). The system utilizes intracellular pH gradients to achieve pH-sensitive sequential release within different intracellular domains of MDR cells. S@L NPs could be triggered to degrade and release CS/PAA/VP-16 NPs in the acid environment of the cytosol, endosomes or lysosomes, and CS/PAA/VP-16 NPs were capable of entering the nucleus through nucleopores. It is significant that CS/PAA/VP-16 NPs exhibit disaggregation in the alkaline environment of the nucleus and thereby release the contained anticancer drug. Further mechanistic studies showed that CS/PAA/VP-16 NPs escaped retention and degradation within lysosomes and protected the drug from P-glycoprotein-induced efflux. Simultaneously, S@L NPs enhanced the anticancer effect of the loaded drug by inducing autophagy and apoptosis of MDR cells. This novel NDDS may provide a promising platform for nuclear drug delivery for reversing MDR.

Plant extracts: from encapsulation to application

INTRODUCTION

Plants are a natural source of various products with diverse biological activities offering treatment for several diseases. Plant extract is a complex mixture of compounds, which can have antioxidant, antibiotic, antiviral, anticancer, antiparasitic, antifungal, hypoglycemic, anti-hypertensive and insecticide properties. The extraction of these extracts requires the use of organic solvents, which not only complicates the formulations but also makes it difficult to directly use the extracts for humans. To overcome these problems, recent research has been focused on developing new ways to formulate the plant extracts and delivering them safely with enhanced therapeutic efficacy.

AREAS COVERED

This review focuses on the research done in the development and use of polymeric nanoparticles for the encapsulation and administration of plant extracts. It describes in detail, the different encapsulation techniques, main physicochemical characteristics of the nanoparticles, toxicity tests and results obtained from in vivo or in vitro assays.

EXPERT OPINION

Major obstacles associated with the use of plant extracts for clinical applications include their complex composition, toxicity risks and extract instability. It is observed that encapsulation can be successfully used to decrease plant extracts toxicity, to provide targeted drug delivery and to solve stability related problems.

Evaluation of endocytosis of silica particles used in biodegradable implants in the brain

Silica nanoparticles embedded in a biodegradable scaffold have been proposed to offer several advantages when used in laser-tissue-soldering of blood vessels in the brain. During degradation, these nanoparticles are likely to be released into the surrounding brain tissue. The aim of this study was to investigate possible cellular uptake mechanism(s) of the two silica nanoparticle types in microglial cells as well as their effect on autophagy and inflammatory cytokines. The nanoparticle uptake was analysed quantitatively using high-content analysis. Nanoparticle incubation did not modulate cytokine secretion and autophagy at any time point investigated. The nanoparticles were taken up by the microglia cells in a time- and particle-dependent manner. The maximal uptake was reached after 4hours and the nanoparticles were found in the endoplasmic reticulum and lysosomes. Macropinocytosis and phagocytosis were predominantly responsible for the uptake, whereas clathrin- and caveolin-independent endocytosis were involved to a minor extent.

An in vitro alveolar macrophage assay for predicting the short-term inhalation toxicity of nanomaterials

BACKGROUND

Most in vitro studies investigating nanomaterial pulmonary toxicity poorly correlate to in vivo inhalation studies. Alveolar macrophages (AMs) play an outstanding role during inhalation exposure since they effectively clear the alveoli from particles. This study addresses the applicability of an in vitro alveolar macrophage assay to distinguish biologically active from passive nanomaterials.

METHODS

Rat NR8383 alveolar macrophages were exposed to 18 inorganic nanomaterials, covering AlOOH, BaSO4, CeO2, Fe2O3, TiO2, ZrO2, and ZnO NMs, amorphous SiO2 and graphite nanoplatelets, and two nanosized organic pigments. ZrO2 and amorphous SiO2 were tested without and with surface functionalization. Non-nanosized quartz DQ12 and corundum were used as positive and negative controls, respectively. The test materials were incubated with the cells in protein-free culture medium. Lactate dehydrogenase, glucuronidase, and tumour necrosis factor alpha were assessed after 16 h. In parallel, H2O2 was assessed after 1.5 h. Using the no-observed-adverse-effect concentrations (NOAECs) from available rat short-term inhalation studies (STIS), the test materials were categorized as active (NOAEC < 10 mg/m(3)) or passive.

RESULTS

In vitro data reflected the STIS categorization if a particle surface area-based threshold of <6000 mm(2)/mL was used to determine the biological relevance of the lowest observed significant in vitro effects. Significant effects that were recorded above this threshold were assessed as resulting from test material-unspecific cellular 'overload'. Test materials were assessed as active if ≥2 of the 4 in vitro parameters undercut this threshold. They were assessed as passive if 0 or 1 parameter was altered. An overall assay accuracy of 95 % was achieved.

CONCLUSIONS

The in vitro NR8383 alveolar macrophage assay allows distinguishing active from passive nanomaterials. Thereby, it allows determining whether in vivo short-term inhalation testing is necessary for hazard assessment. Results may also be used to group nanomaterials by biological activity. Further work should aim at validating the assay.

New acrylate terpolymer-based nanoparticles for the release of nucleic acid: a preliminary study

PURPOSE

Nano-drug delivery systems based on polymeric biomaterials have received considerable interest as drug delivery vehicles. In this work, radical polymerization was carried out in order to obtain nanoparticles based on a new acrylate terpolymer (PBMA-(PEG)MEMA-PDMAEMA).

METHODS

Nanoparticles were developed in the form both of nanospheres and nanocapsules, an innovative kind of hollow nanoparticles with a great potential because of their low effective density and high specific surface area. The ability of the nanoparticles to load and then release a nucleic acid (DNA) to be used in cancer treatment was also investigated.

RESULTS

Scanning electron microscopy analysis showed a spherical shape, nanometric dimensions, and a homogeneous distribution of the nanoparticles, also confirmed by dynamic light scattering measurements. Fourier-transform infrared spectroscopy chemical imaging analysis carried out on the nanocapsules before and after removal of the core demonstrated the presence of the cavity. High-performance liquid chromatography analysis confirmed good encapsulation efficiency of DNA both for nanospheres and nanocapsules. Drug release tests showed controlled release kinetics for both the systems with a high release of DNA in the first hours. In vitro MTT assay showed that the particles do not have cytotoxic effects on the cells.

CONCLUSIONS

The preliminary investigation showed that the terpolymer-based nanoparticles developed in this study could be good candidates to be used as innovative and versatile gene delivery systems.

Nanomedicine and nanotoxicology: the pros and cons for neurodegeneration and brain cancer

Current strategies for brain diseases are mostly symptomatic and noncurative. Nanotechnology has the potential to facilitate the transport of drugs across the blood-brain barrier and to enhance their pharmacokinetic profile. However, to reach clinical application, an understanding of nanoneurotoxicity in terms of oxidative stress and inflammation is required. Emerging evidence has also shown that nanoparticles have the ability to alter autophagy, which can induce inflammation and oxidative stress, or vice versa. These effects may increase neurodegenerative processes damage, but on the other hand, they may have benefits for brain cancer therapies. In this review, we emphasize how nanomaterials may induce neurotoxic effects focusing on neurodegeneration, and how these effects could be exploited toward brain cancer treatment.

The autophagic response to polystyrene nanoparticles is mediated by transcription factor EB and depends on surface charge

BACKGROUND

A number of engineered nanoparticles induce autophagy, the main catabolic pathway that regulates bulk degradation of cytoplasmic material by the lysosomes. Depending on the specific physico-chemical properties of the nanomaterial, however, nanoparticle-induced autophagy may have different effects on cell physiology, ranging from enhanced autophagic degradation to blockage of autophagic flux. To investigate the molecular mechanisms underlying the impact of nanoparticle charge on the nature of the autophagic response, we tested polystyrene nanoparticles (50 nm) with neutral, anionic, and cationic surface charges.

RESULTS

We found all polystyrene nanoparticles investigated in this study to activate autophagy. We showed that internalization of polystyrene nanoparticles results in activation of the transcription factor EB, a master regulator of autophagy and lysosome biogenesis. Autophagic clearance, however, was observed to depend specifically on the charge of the nanoparticles. Particularly, we found that the autophagic response to polystyrene nanoparticles presenting a neutral or anionic surface involves enhanced clearance of autophagic cargo. Cell exposure to polystyrene nanoparticles presenting a cationic surface, on the other hand, results in transcriptional upregulation of the pathway, but also causes lysosomal dysfunction, ultimately resulting in blockage of autophagic flux.

CONCLUSIONS

This study furthers our understanding of the molecular mechanisms that regulate the autophagic response to nanoparticles, thus contributing essential design criteria for engineering benign nanomaterials.

Challenges in carrier-mediated intracellular delivery: moving beyond endosomal barriers

The deployment of molecular to microscale carriers for intracellular delivery has tremendous potential for biology and medicine, especially for in vivo therapies. The field remains limited, however, by a poor understanding of how carriers gain access to the cell interior. In this review, we provide an overview of the different types of carriers, their speculated modes of entry, putative pathways of vesicular transport, and sites of endosomal escape. We compare this alongside pertinent examples from the cell biology of how viruses, bacteria, and their effectors enter cells and escape endosomal confinement. We anticipate insights into the mechanisms of cellular entry and endosomal escape will benefit future research efforts on effective carrier-mediated intracellular delivery. WIREs Nanomed Nanobiotechnol 2016, 8:465-478. doi: 10.1002/wnan.1377 For further resources related to this article, please visit the WIREs website.

Non-genetic engineering of cells for drug delivery and cell-based therapy

Cell-based therapy is a promising modality to address many unmet medical needs. In addition to genetic engineering, material-based, biochemical, and physical science-based approaches have emerged as novel approaches to modify cells. Non-genetic engineering of cells has been applied in delivering therapeutics to tissues, homing of cells to the bone marrow or inflammatory tissues, cancer imaging, immunotherapy, and remotely controlling cellular functions. This new strategy has unique advantages in disease therapy and is complementary to existing gene-based cell engineering approaches. A better understanding of cellular systems and different engineering methods will allow us to better exploit engineered cells in biomedicine. Here, we review non-genetic cell engineering techniques and applications of engineered cells, discuss the pros and cons of different methods, and provide our perspectives on future research directions.

Fluorescent nanodiamonds as a relevant tag for the assessment of alum adjuvant particle biodisposition

BACKGROUND

Aluminum oxyhydroxide (alum) is a crystalline compound widely used as an immunologic adjuvant of vaccines. Concerns linked to alum particles have emerged following recognition of their causative role in the so-called macrophagic myofasciitis (MMF) lesion in patients with myalgic encephalomyelitis, revealing an unexpectedly long-lasting biopersistence of alum within immune cells and a fundamental misconception of its biodisposition. Evidence that aluminum-coated particles phagocytozed in the injected muscle and its draining lymph nodes can disseminate within phagocytes throughout the body and slowly accumulate in the brain further suggested that alum safety should be evaluated in the long term. However, lack of specific staining makes difficult the assessment of low quantities of bona fide alum adjuvant particles in tissues.

METHODS

We explored the feasibility of using fluorescent functionalized nanodiamonds (mfNDs) as a permanent label of alum (Alhydrogel(®)). mfNDs have a specific and perfectly photostable fluorescence based on the presence within the diamond lattice of nitrogen-vacancy centers (NV centers). As the NV center does not bleach, it allows the microspectrometric detection of mfNDs at very low levels and in the long-term. We thus developed fluorescent nanodiamonds functionalized by hyperbranched polyglycerol (mfNDs) allowing good coupling and stability of alum:mfNDs (AluDia) complexes. Specificities of AluDia complexes were comparable to the whole reference vaccine (anti-hepatitis B vaccine) in terms of particle size and zeta potential.

RESULTS

In vivo, AluDia injection was followed by prompt phagocytosis and AluDia particles remained easily detectable by the specific signal of the fND particles in the injected muscle, draining lymph nodes, spleen, liver and brain. In vitro, mfNDs had low toxicity on THP-1 cells and AluDia showed cell toxicity similar to alum alone. Expectedly, AluDia elicited autophagy, and allowed highly specific detection of small amounts of alum in autophagosomes.

CONCLUSIONS

The fluorescent nanodiamond technology is able to overcome the limitations of previously used organic fluorophores, thus appearing as a choice methodology for studying distribution, persistence and long-term neurotoxicity of alum adjuvants and beyond of other types of nanoparticles.

Unravelling "off-target" effects of redox-active polymers and polymer multilayered capsules in prostate cancer cells

Redox-active polymers and carriers are oxidizing nanoagents that can potentially trigger intracellular off-target effects. In the present study, we investigated the occurrence of off-target effects in prostate cancer cells following exposure to redox-active polymer and thin multilayer capsules with different chemical properties. We show that, depending on the intracellular antioxidant capacity, thiol-functionalized poly(methacrylic acid), PMA(SH) triggers cell defense responses/perturbations that result in off-target effects (i.e., induction of autophagy and down-regulation of survivin). Importantly, the conversion of the carboxyl groups of PMA(SH) into the neutral amides of poly(hydroxypropylmetacrylamide) (pHPMA(SH)) nullified the off-target effects and cytotoxicity in tested cell lines. This suggests that the simultaneous action of carboxyl and disulfide groups in PMA(SH) polymer or capsules may play a role in mediating the intracellular off-target effects. Our work provides evidence that the rational design of redox-active carriers for therapeutic-related application should be guided by a careful investigation on potential disturbance of the cellular machineries related to the carrier association.

Impact of nanoparticles on human and environment: review of toxicity factors, exposures, control strategies, and future prospects

Nanotechnology has revolutionized the world through introduction of a unique class of materials and consumer products in many arenas. It has led to production of innovative materials and devices. Despite of their unique advantages and applications in domestic and industrial sectors, use of materials with dimensions in nanometers has raised the issue of safety for workers, consumers, and human environment. Because of their small size and other unique characteristics, nanoparticles have ability to harm human and wildlife by interacting through various mechanisms. We have reviewed the characteristics of nanoparticles which form the basis of their toxicity. This paper also reviews possible routes of exposure of nanoparticles to human body. Dermal contact, inhalation, and ingestion have been discussed in detail. As very limited data is available for long-term human exposures, there is a pressing need to develop the methods which can determine short and long-term effects of nanoparticles on human and environment. We also discuss in brief the strategies which can help to control human exposures to toxic nanoparticles. We have outlined the current status of toxicological studies dealing with nanoparticles, accomplishments, weaknesses, and future challenges.

Dimethylaminoethyl methacrylate copolymer-siRNA nanoparticles for silencing a therapeutically relevant gene in macrophages

DMC nanoparticles target Bfl1/A1 gene in lung macrophages and effective silencing of Bfl1/A1 gene by DMC nanoparticles paves the way for research on alternative treatment strategies for tuberculosis.

Selective elevation of circulating CCL2/MCP1 levels in patients with longstanding post-vaccinal macrophagic myofasciitis and ASIA

Several medical conditions sharing similar signs and symptoms may be related to immune adjuvants. These conditions described as ASIA (Autoimmune/inflammatory Syndrome Induced by Adjuvants), include a condition characterized by macrophagic myofasciitis (MMF) assessing long-term persistence of vaccine derived-alum adjuvants into macrophages at sites of previous immunization. Despite increasing data describing clinical manifestations of ASIA have been reported, biological markers are particularly lacking for their characterization and follow up. We report an extensive cytokine screening performed in serum from 44 MMF patients compared both to sex and age matched healthy controls and to patients with various types of inflammatory neuromuscular diseases. Thirty cytokines were quantified using combination of Luminex® technology and ELISA. There was significant mean increase of serum levels of the monocytechemoattractant protein 1 (CCL2/MCP-1) in MMF patients compared to healthy subjects. MMF patients showed no elevation of other cytokines. This contrasted with inflammatory patients in whom CCL2/MCP-1 serum levels were unchanged, whereas several other inflammatory cytokines were elevated (IL1β, IL5 and CCL3/MIP1α). These results suggest that CCL2 may represent a biological marker relevant to the pathophysiology of MMF rather than a non specific inflammatory marker and that it should be checked in the other syndromes constitutive of ASIA.

Development of wheat glutenin nanoparticles and their biodistribution in mice

Wheat glutenin nanoparticles intended for targeted drug delivery were biocompatible and were detected in the kidney, liver, and spleen in mice. Protein-based nanoparticles are preferred for therapeutic drug and gene delivery owing to their biocompatibility and ability to load various types of drugs. However, proteins such as a collagen and albumin are unstable in aqueous environments and are not ideal for drug delivery applications. Wheat glutenin has been demonstrated to be biocompatible and have good stability under aqueous conditions. Films and fibers have been made from wheat glutenin for medical applications but there are no reports on developing micro- or nanoparticles. In this research, wheat glutenin nanoparticles (70-140 nm) were prepared and the stability of the nanoparticles under various physiological conditions was investigated. Nanoparticles were fluorescently labeled and later injected into mice and the ability of the nanoparticles to penetrate into the cells in various organs was studied. Strong acidic or alkaline conditions provided glutenin nanoparticles with low diameters and the particles were more stable under the pH 7 rather than pH of 4. Glutenin nanoparticles were predominantly found in the liver in mice. Our in vivo and in vitro studies suggest that glutenin nanoparticles are suitable for drug delivery applications.

Autophagy as a Possible Underlying Mechanism of Nanomaterial Toxicity

The rapid development of nanotechnologies is raising safety concerns because of the potential effects of engineered nanomaterials on human health, particularly at the respiratory level. Since the last decades, many in vivo studies have been interested in the pulmonary effects of different classes of nanomaterials. It has been shown that some of them can induce toxic effects, essentially depending on their physico-chemical characteristics, but other studies did not identify such effects. Inflammation and oxidative stress are currently the two main mechanisms described to explain the observed toxicity. However, the exact underlying mechanism(s) still remain(s) unknown and autophagy could represent an interesting candidate. Autophagy is a physiological process in which cytoplasmic components are digested via a lysosomal pathway. It has been shown that autophagy is involved in the pathogenesis and the progression of human diseases, and is able to modulate the oxidative stress and pro-inflammatory responses. A growing amount of literature suggests that a link between nanomaterial toxicity and autophagy impairment could exist. In this review, we will first summarize what is known about the respiratory effects of nanomaterials and we will then discuss the possible involvement of autophagy in this toxicity. This review should help understand why autophagy impairment could be taken as a promising candidate to fully understand nanomaterials toxicity.