Platelets not only play a key role in blood clotting, but can also significantly intensify inflammatory processes. This is shown by a new study that could open up new ways to treat autoimmune diseases. The results are published in the journal Cell Reports.
For a long time, the role of platelets appeared to be clear: in the event of an injury, they adhere to the wound and stick to each other to rapidly stop the bleeding. This wound closure mechanism works quickly and efficiently, but its protagonists were not considered to have any other functions.
For some years now, this picture has begun to change significantly: these tiny cells, each of which is about the size of an intestinal bacterium, are also believed to perform important functions in the immune system. The current study supports this thesis: it shows that platelets ensure that the white blood cells (the leukocytes) secrete significantly more inflammatory messengers. "It is possible that this effect contributes to the often severe course of autoimmune diseases," explains the senior author. "These are diseases in which the immune system attacks and destroys the body's own tissue."
In their study, the researchers focused on an important immune mechanism: the activation of the NLRP3 inflammasome. Inflammasomes are molecular machines that consist of a number of different proteins. Among other things, they are able to convert inactive inflammatory messengers into their active form. One of them is the interleukin 1 (IL-1). When cells secrete IL-1, they call on other immune cells to help and thereby trigger a strong inflammatory reaction. As this can also become dangerous for the body, the activity of the inflammasomes, and hence also the formation of IL-1, is strictly regulated.
"We have now been able to demonstrate that platelets interfere with this regulation," explains the first author of the study: "They cause certain white blood cells, the macrophages and neutrophilic granulocytes, to form more active inflammasomes." To do this, they apparently release a whole cocktail of substances that diffuse to the white blood cells. Once there, these ensure, among other things, that certain genes required for the construction of the inflammasomes are more frequently expressed. This effect does not require the platelets to make direct contact with the macrophages or granulocytes. Instead, they release their active substances into the environment, for example, into the blood.
"To prove that, we incubated human platelets in the laboratory and then filtered them off, so the platelet factor could be present in the culture medium," explains the author. "When we added this platelet medium to human white blood cells, the formation of inflammasomes and the IL-1 production were significantly boosted." Exactly which of the substances released by the platelets are responsible for this process is not yet known. However, the effect was supported by observations in human malaria patients: the more platelets they have, the higher the IL-1 concentration in their plasma. The researchers also experimentally reduced the number of platelets in mice. The animals then released significantly less IL-1 after being injected with inflammatory compounds.
As IL-1 promotes inflammation, the messenger substance can significantly worsen the course of autoimmune diseases. Nevertheless, the lead author is keen to speak up against a one-sided view of platelets as villains: they also intervene in other ways in the immune response, for example by preventing the development of life-threatening sepsis after an infection. Regardless of this, the results might pave the way to new therapies for diseases such as rheumatism or diabetes.
However, one important message of the current study is of a more general nature: isolated blood cells in culture often behave very differently than in their natural environment, where they communicate with numerous other cells. "Experiments in the test tube therefore do not provide complete insight into the processes happening in the body," emphasizes the senior author. "Still, most of research into inflammasomes are based on them, which is a fact we should rethink." After all, platelets may only reveal their additional immune functions in concert with white blood cells.
https://www.uni-bonn.de/news/119-2020
https://www.cell.com/cell-reports/fulltext/S2211-1247(20)30564-7
http://sciencemission.com/site/index.php?page=news&type=view&id=publications%2Fplatelets-fuel-the&filter=22
Platelets exacerbate immune response
- 1,511 views
- Added
Edited
Latest News
DNA attached to nanoparticl…
By newseditor
Posted 29 Mar
Neighboring synapses shape…
By newseditor
Posted 29 Mar
Complete vascularization of…
By newseditor
Posted 28 Mar
Immune cells identified as…
By newseditor
Posted 28 Mar
TB blood test which could d…
By newseditor
Posted 27 Mar
Other Top Stories
How taking breaks enhances learning process
Read more
Eating soft foods may alter the brain's control of chewing
Read more
A link between childhood stress and early molars
Read more
Omega-6 fatty acid-enriched western diet induces reversible periphe…
Read more
What is Thanatosis?
Read more
Protocols
Spatial proteomics in neuro…
By newseditor
Posted 28 Mar
All-optical presynaptic pla…
By newseditor
Posted 23 Mar
Epigenomic tomography for p…
By newseditor
Posted 20 Mar
A mouse DRG genetic toolkit…
By newseditor
Posted 17 Mar
An optogenetic method for t…
By newseditor
Posted 13 Mar
Publications
DNA corona on nanoparticles…
By newseditor
Posted 29 Mar
Co-dependent excitatory and…
By newseditor
Posted 29 Mar
A microfluidic platform int…
By newseditor
Posted 28 Mar
Salmonella manipulates macr…
By newseditor
Posted 28 Mar
BHLHE40/41 regulate microgl…
By newseditor
Posted 28 Mar
Presentations
Hydrogels in Drug Delivery
By newseditor
Posted 12 Apr
Lipids
By newseditor
Posted 31 Dec
Cell biology of carbohydrat…
By newseditor
Posted 29 Nov
RNA interference (RNAi)
By newseditor
Posted 23 Oct
RNA structure and functions
By newseditor
Posted 19 Oct
Posters
A chemical biology/modular…
By newseditor
Posted 22 Aug
Single-molecule covalent ma…
By newseditor
Posted 04 Jul
ASCO-2020-HEALTH SERVICES R…
By newseditor
Posted 23 Mar
ASCO-2020-HEAD AND NECK CANCER
By newseditor
Posted 23 Mar
ASCO-2020-GENITOURINARY CAN…
By newseditor
Posted 23 Mar