About this Research Topic
Neutrophils have been long known to be the first responders to arrive at sites of infection and inflammation where they initiate a rapid response against microbes. However, discoveries during more recent years have revealed that neutrophils do much more than that. They are equipped with an array of molecules that they use to interact with other immune and non-immune cells. Consequently, they are important in shaping both innate and adaptive immune responses and are therefore critical players in the development and progression of various inflammatory and autoimmune diseases and our protective immunity against pathogens.
We now know that neutrophils can have both pro and anti-inflammatory functions which are highly dependent on the timing, the context, and the type of signals they receive. They can promote inflammation through the release of microvesicles and various molecules including their granule enzymes such as proteases and myeloperoxidase (MPO), as well as reactive oxidants, neutrophil extracellular traps (NETs), cytokines, and chemokines. The release of neutrophil enzymes and other bioactive macromolecules may introduce post-translational modifications into surrounding host tissues, in the process providing neo-antigens and contributing to tissue damage. In contrast, neutrophils also have a critical role in the resolution of inflammation, often through their interactions with macrophages, and subsequent tissue repair. In addition, they can both positively and negatively regulate the development of adaptive immunity in secondary lymphoid organs through their effects on dendritic cells, T cells, and B cells. In some instances, it has become evident that neutrophils can even themselves act as antigen-presenting cells to activate T cells. They also provide a rich source of autoantigens such as proteinase-3 and MPO, the autoimmunity to which causes severe inflammation of small blood vessels or vasculitis. Furthermore, research over the last decade has uncovered that neutrophils, acting as immunosuppressive granulocytic myeloid-derived suppressor cells (MDSC), can promote cancer growth, but, on the other hand, have a protective role in autoimmune diseases.
It is clear that there are still many undiscovered functions of neutrophils in immunity and that more research is needed to fully understand these phagocytes. The aim of this Research Topic is to expand our knowledge about the new and diverse roles of neutrophils and granulocytic MDSC as regulators of the immune system, with a special focus on autoimmune diseases, inflammation, and immunity against pathogens.
We welcome the submission of Original Research articles, Reviews, Mini-Reviews, Perspectives, Methods, and Hypothesis and Theory that cover the following topics:
1. Neutrophils as antigen-presenting cells and regulators of adaptive immunity in secondary lymphoid organs
2. The role of neutrophil granule components and microvesicles in innate and adaptive immunity
3. NETs as regulators of innate and adaptive immune responses
4. New roles and mechanisms of granulocytic MDSC in autoimmunity, inflammation, and immunity against pathogens
5. Novel insights into autoimmunity against neutrophil-derived autoantigens
6. Therapeutic targeting of neutrophils or their constituents as a treatment for inflammatory and autoimmune diseases
Keywords: neutrophils, myeloid suppressor cells, NETs, myeloperoxidase, MPO, inflammation, autoimmunity, infection, microvesicles, exosomes, MDSC
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