Sinnema, N. (2014) Netting Neutrophils. Master's Thesis / Essay, Biology.
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Abstract
NETosis is a form of cell death used by neutrophils to trap microorganisms. NETosis is induced by microorganisms, but also by inflammatory stimuli like cytokines, antibodies and HMGB1.The formation of NETs is dependent on a correct working of the NADPH-oxidative complex and the formation of ROS. NETosis plays a role in innate immunity, but has also a pathogenic role in auto-immune diseases like SLE and UC. NETs form a pool of auto-antigens because NET components like DNA, histones, and granular proteins are available in the extracellular space. This makes it easy for auto-antigens to bind. A hypothesis is that NETs can directly stimulate B-cell to produce (auto)antibodies. NETosis could play a crucial role in the manifestation of auto-immune diseases, and therefore it is important to study this subject. Therapeutics that can inhibit NETosis might be necessary. From this study can be concluded that NETs are formed after 3 hours, but change in form and composition after 4 hours. After 4 hours of stimulation MPO leaves NETs and the NETs have a more dread-like structure compared to the cloud-like structure of NETs after 3 hours of stimulation. NETosis can be induced by PMA, LPS and HMGB1 in healthy controls. Neutrophils from SLE patients show a higher spontaneous NETosis, but the difference with healthy controls is not significant. This may be caused by the inclusion of quiescent patients in this study. Neutrophils from SLE patients form NETs after stimulation with PMA, but not after stimulation with LPS or HMGB1. This could be caused by the medication used by the patients. NETosis could be inhibited by 5-ASA and Cigarette Smoke Extract (CSE), but not by prednisolone or hydroxychloroquine. After pre-treatment with 5-ASA the amount of NETs is decreased, but neutrophils do show signs of activation. The cells are stretched-out and have a round nucleus. CSE paralyses neutrophils and inhibits NETosis in an early state of the signal transduction route. Neutrophils pre-treated with CSE maintain their round shape and polymorph nucleus. It is important to find the working compound and the working mechanism behind CSE. NETs do not increase the amount of IgG found in B-cell supernatants. It could be the case that NETs inhibit antibody production of B-cells, but other reasons like the trapping of IgG by NETs should be excluded.
| Item Type: | Thesis (Master's Thesis / Essay) |
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| Degree programme: | Biology |
| Thesis type: | Master's Thesis / Essay |
| Language: | English |
| Date Deposited: | 15 Feb 2018 08:03 |
| Last Modified: | 15 Feb 2018 08:03 |
| URI: | https://fse.studenttheses.ub.rug.nl/id/eprint/12569 |
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