Cell 'cannibalism' captured
Image: Immune cells - 'macrophages' - ingesting another cell or with another cell already in their interior. [CNIC]
Spain-based researchers have unveiled stunning images of immune cells ingesting other cells.
The images of cell 'cannabalism' are part of research at the Centro Nacional de Investigadores Cardiovasculares Carlos III (CNIC) that is shedding slight on how specialised cells ingest and degrade old, dead or damaged cells to prevent accumulation and tissue damage.
Researchers have long investigated how organisms eliminate debris from dead cells, as well as rogue cells, with the most common mechanism being a digestive process called phagocytosis, carried out by 'macrophage' immune cells.
But by using an ingenious method for joining the circulations of two mice, with the cells of one mouse expressing a fluorescent protein, Noelia Alonso-González and Andrés Hidalgo have shown how the process is organised in living tissue.
Results indicate that phagocytosing macrophages are different in each tissue, and different from macrophages that do not ingest dead or damaged cells.
Microscopy images of macrophages in the process of ingesting another cell or with another cell already in their interior. The images on the right show this process in living tissues, with the phagocytosed cell in green and the macrophage in red. In these examples, the ingested cells are neutrophils. [CNIC/Jose María Adrover Montemayor (left), Noelia Alonso González (right)]
Crucially, the researchers also reveal that the act of ingesting expired cells educates the immune system in how to maintain tissues in a clean and healthy state, and that macrophages play a critical role in this process.
The researchers were able to pinpoint the different molecules that carry out important tasks in the phagocytic process in each tissue, from the gut to the liver and bone marrow.
What's more, they also discovered that each tissue has its own specific molecular toolkit for eliminating unwanted cells.
As Alonso-González highlights: "This discovery suggests that it should in principle be possible to modulate phagocytosis in individual organs, without altering events in neighboring organs."
"One could, for example, promote the elimination of dangerous cells in the spleen without risking elimination of beneficial cells in the lung," she adds.
Research is published in the Journal of Experimental Medicine.