Nanoparticles' toxic effects on macrophages Nanoparticles macrophages Nanotoxicity Cytotoxicity Toxicity Cellularinternalization ElsevierNews
By Dr. Priyom Bose, Ph.D.Jul 31 2022Reviewed by Benedette Cuffari, M.Sc. Due to the extensive usage of nanoparticles, toxicologists and scientists alike are interested in better understanding their safety profile. The toxic effects of nanoparticles on macrophages, for example, warrants further study, as these immune cells are often the first to encounter nanoparticles after they enter the body.
Background Nanoparticles can be both engineered or natural particles that are smaller than 100 nanometers in at least one dimension. Over the past several decades, nanotechnology has evolved rapidly, which has subsequently increased the demand for nanoparticles like titanium dioxide, zinc oxide , graphene, and smaller quantum dots. These nanoparticles, which are widely used in many industries, including clothes, food, and cosmetics, have small sizes and excellent optical properties.
Macrophages, which belong to both the immune and mononuclear phagocytic systems , are essential members of the immune response, as they phagocytize approximately 95% of invading nanoparticles. However, macrophages are susceptible to foreign nanoparticles and are, as a result, partly involved in the process of tissue injury.
Related StoriesThe physicochemical factors influencing the cytotoxicity of macrophages following nanoparticle exposure have also been assessed. To this end, the size, shape, charge, and surface properties of nanoparticles can affect their uptake and cell interactions. The surface modification of nanoparticles also contributes to their overall cytotoxicity. For example, silica coating significantly improves the biocompatibility of gadolinium oxide nanoparticles and, as a result, reduces their cytotoxicity.
The mechanism of ROS production is different across nanoparticles, with the mitochondria being the main source of ROS production. Importantly, not all nanoparticles induce ROS production, with the majority of metal nanoparticles generating toxicity through the induction of a hydroxyl reaction by means of a Fenton-type reaction.
United States Latest News, United States Headlines
Similar News:You can also read news stories similar to this one that we have collected from other news sources.
Boy Meets World stars slam boss for 'toxic work environment'Danielle Fishel opens up about how she was embarrassed in front of the cast and crew.
Read more »
Monkeypox is not a cover-up for the effects of the Covid-19 vaccine - Full FactThere’s no evidence of any link between the recent monkeypox virus outbreak and the Covid-19 vaccines, which do not damage immune systems, as a video claims.
Read more »
Large-scale manipulation of promoter DNA methylation reveals context-specific transcriptional responses and stability - Genome BiologyBackground Cytosine DNA methylation is widely described as a transcriptional repressive mark with the capacity to silence promoters. Epigenome engineering techniques enable direct testing of the effect of induced DNA methylation on endogenous promoters; however, the downstream effects have not yet been comprehensively assessed. Results Here, we simultaneously induce methylation at thousands of promoters in human cells using an engineered zinc finger-DNMT3A fusion protein, enabling us to test the effect of forced DNA methylation upon transcription, chromatin accessibility, histone modifications, and DNA methylation persistence after the removal of the fusion protein. We find that transcriptional responses to DNA methylation are highly context-specific, including lack of repression, as well as cases of increased gene expression, which appears to be driven by the eviction of methyl-sensitive transcriptional repressors. Furthermore, we find that some regulatory networks can override DNA methylation and that promoter methylation can cause alternative promoter usage. DNA methylation deposited at promoter and distal regulatory regions is rapidly erased after removal of the zinc finger-DNMT3A fusion protein, in a process combining passive and TET-mediated demethylation. Finally, we demonstrate that induced DNA methylation can exist simultaneously on promoter nucleosomes that possess the active histone modification H3K4me3, or DNA bound by the initiated form of RNA polymerase II. Conclusions These findings have important implications for epigenome engineering and demonstrate that the response of promoters to DNA methylation is more complex than previously appreciated.
Read more »