Identification and characterization of novel inflammasome molecules and pathways

• Applicant: Dr. Jens Kortmann
• Subject Area: Immunology
• Term: from 2012 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 221939457

A hallmark of salmonellosis is the ability of its causative agent, Salmonella, to survive and replicate within macrophages. Macrophages are able to detect intracellular Salmonella via a set of cytosolic receptors that recognize specific bacterial patterns. One example is the NLRC4 receptor, which is very specific for molecules such as flagellin or parts of the type III secretion system. This intracellular recognition leads to the assembly of a host-protective multimolecular complex termed inflammasome. The inflammasome promotes (i) the caspase-1-dependent release of immunological signalling molecules (cytokines) and (ii) the pro-inflammatory macrophage cell death (pyroptosis). Pyroptosis removes the intracellular niche of microbial replication and re-exposes the pathogen to extracellular immune responses. Recent results indicate that a spatially distinct inflammasome complex (death complex) might govern pyroptosis. Despite its central role in immunity, the precise molecular architecture and composition of inflammasome complexes remains largely unknown. The death complex lacks an adaptor protein crucial for proper assembly of the inflammasome. Its function is adopted by adaptor-like features of the NLRC4 receptor mentioned above. This circumstance allows the usage of the NLRC4 receptor as bait for co-precipitation of novel death complex binding partners. All novel proteins identified with this approach will be analyzed further to determine their role in inflammasome assembly, cytokine release and activating or inhibiting pyroptosis by knocking down their expression via shRNA (short hairpin RNA) constructs. I will perform the relevant phenotypic analysis at single macrophage cell level by using time-lapse video microscopy.

• DFG Programme: Research Fellowships
• International Connection: USA
• Host: Professorin Denise Monack, Ph.D.