A new study published in Scientific Reports examining how nanoparticles interact with mast cells offers insights into the role these microscopic particles may play in the cellular pathway of allergic response.
Mast cells are found throughout body tissues and play a central role in allergic reactions: when triggered, they release a flood of inflammatory chemicals that cause the swelling, redness and irritation associated with allergies. In people with mast cellMast cell A type of white blood cell produced in the bone marrow. They help defend against infections and play a key role in allergic reactions. In SM, mast cells become overactive and build up throughout the body. disorders such as systemic mastocytosis (SM), these cells are abnormally abundant and prone to excessive activation.
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The researchers exposed laboratory-grown mast cells, sensitized with an allergy antibody (immunoglobulin E) to mimic an allergic state, to two different nanoparticles: negatively charged silica (SiO2) and manganese-doped titanium dioxide (mTiO2). They then measured how each nanoparticle affected mast cell behavior, both on its own and when combined with an allergen.
The results were notably different between the two particles. When silica nanoparticles were introduced at the same time as an allergen, they reduced degranulation, the process by which mast cells release their inflammatory contents, by roughly 50% at moderate doses, and nearly completely at higher doses. They also reduced levels of interleukin-13, an inflammatory signaling protein (called a cytokine) that is elevated in allergic skin conditions.
Titanium dioxide nanoparticles had the opposite effect. They were toxic to mast cells at higher doses, and at lower doses they independently triggered signs of mast cell activationMast cell activation Describes when mast cells release histamine and other mediators into the blood stream in response to an allergen or other trigger. This leads to symptoms like fatigue, rash and, in severe cases, anaphylaxis., including the release of TNF-α, another pro-inflammatory cytokine. When combined with an allergen, titanium dioxide nanoparticles worsened the release of the inflammatory cytokine interleukin-6.
The team also tracked changes in proteins on the surface of mast cells that signal whether the cells are activated. Silica nanoparticles suppressed these activation signals in the presence of an allergen, whereas titanium dioxide nanoparticles triggered them in the absence of an allergen.
“In summary, this work builds on our knowledge base showing how [nanoparticles] can modulate [bone marrow mast cell] activation and related cell surface markers that can be used to predict the effects of unknown compounds on mast cell activation,” the authors highlighted, noting the findings are consistent with earlier animal studies showing silica nanoparticles reduced allergic skin responses in mice.
The findings contribute to a broader body of research on whether nanoparticles can be designed to reach specific immune cells and modulate targeted immune responses. This approach is considered potentially more precise than systemic immunosuppressants, the most commonly used drugs for allergy treatment, which work by broadly suppressing the immune system and can carry significant side effects with long-term use.
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