The future of phagosome research begins in Jena: Thuringia funds a new research group at the Leibniz-HKI

| by Charlotte Fuchs

Lung epithelial cells infected with the fungal pathogen Aspergillus fumigatus. Several fungal conidia are swallowed by the host cells in phagosomes.
On the screen are shown lung epithelial cells (green and red) infected with the fungal pathogen Aspergillus fumigatus (blue). Several fungal conidia are engulfed by the host cells in phagosomes (in green circle). Source: Anna Schroll / Leibniz-HKI

At the beginning of January, the Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI) expanded to include a new research group. Under the leadership of Leijie Jia, the group aims to unravel the secrets of fungal-host interactions in the context of phagocytosis and is thus breaking new ground towards a better understanding of phagosome-related processes. The group is financed by the Free State of Thuringia with funds from the European Social Fund Plus.

Invasive fungal infections cause serious diseases with a high mortality rate in people with weakened immune systems. In October 2022, the WHO published its first list of "priority", i.e. medium, high or critical priority, disease-causing fungal pathogens, emphasizing the enormous importance of research into fungal infections. In the list, the four fungal species Aspergillus fumigatus, Candida albicans, Candida auris and Cryptococcus neoformans are rated as particularly critical, as they cause invasive infections in around 6.5 million people worldwide each year, for the treatment of which only a few antifungal drugs are available.

Several studies show that the human innate immune system is part of the first line of defense against fungal infections. It was found that, in addition to the cells known as "phagocytes", epithelial cells are also able to take up fungal pathogens and kill them intracellularly. The uptake of particles by cells is known as phagocytosis. Alongside muscles, nerves and connective tissue, epithelial cells form one of the four basic tissue types, the epithelial tissue. This covers both internal and external body surfaces and serves, among other things, to seal and protect against the outside world.

Leijie Jia in the laboratory
Leijie Jia transfers proteins from a gel to a membrane, as a step of Western blotting, a method to detect specific proteins. Source: Anna Schroll / Leibniz HKI

The process of phagocytosis, i.e. the uptake of pathogens and their processing, involves the formation of a special intracellular structure that kills the pathogen, the phagolysosome. However, all the fungi mentioned above and also many bacteria, for example the tuberculosis pathogen Mycobacterium tuberculosis, have developed strategies to evade killing in the phagolysosome. This type of suppression of the immune response allows the infection to progress further.

The new Phagosome Biology and Engineering research group, founded at the beginning of 2024, is headed by Dr. Leijie Jia. Jia received his doctorate from the Chinese Academy of Sciences in Shanghai, China in 2016 and then moved to the Center for Excellence in Molecular Plant Sciences in Shanghai before joining the Leibniz-HKI as a postdoc.

Leijie Jia is pursuing two goals with his own group: On the one hand, he wants to research the pathogen-induced reprogramming of phagosomes and better understand the mechanisms by which fungal pathogens circumvent killing in the phagosome. On the other hand, the research group will use these findings to develop new strategies to better combat fungal infections.

Leijie Jia's research program convinced the jury of the Thuringian funding program for research groups, which is supervised by the Thüringer Aufbaubank. With the new research group, the Leibniz-HKI is further expanding its position as the most important research center for life-threatening fungal infections in Germany and consistently developing its research profile: "Leijie Jia is an extremely talented young scientist. His group fits in with our mission to advance research into fungal infections and develop new, more effective treatments. We are confident that Dr. Jia and his team will make an important contribution to this field and are therefore very pleased about the funding from the Free State of Thuringia", said Axel Brakhage, Director of the Leibniz-HKI.


Leijie Jia