Effect of selective interventions on the spatial organization of an inflammation

• Applicant: Professor Dr. Klaus Scholich
• Subject Area: Pharmacology
• Term: from 2010 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 175655649

An inflammation can be roughly divided in two phases: the proinflammatory phase and the resolution of inflammation. At nearly any given time point during these phases, pro- as well as antiinflammatory processes can be observed. Thus, functionally different microenvironments can be defined based on the differential spatial localization of pro- and antiinflammatory mediators and immune cells. Immune cells respond to signals they receive from their microenvironment by adjusting their actions to the needs of the specific local situation. Therefore, to understand the mechanisms, which regulate immune cell phenotypes and functions, in the context of an inflammation, it is necessary to characterize their microenvironment and specifically the spatial relations between the different immune cell populations forming these microenvironments.One technology, which is especially useful to characterize microenvironments, is the Multi-Epitope-Ligand-Cartography (MELC). MELC is an imaging technology for sequential immunohistology, which we use to visualize over 40 proteins on the same tissue slice. In the previous funding period we employed this system to investigate signaling pathways, which regulate the proinflammatory functions of macrophages and mast cells. The data showed a specific spatial distribution of the immune cells in regard to the injected pathogen (zymosan). Here, a core region can be defined, which comprises the pathogen, neutrophils and proinflammatory macrophages. This core region is surrounded by a region dominated by antiinflammatory macrophages and antiinflammatory mediators. The intermediary area between the core and the antiinflammatory region is characterized by dendritic cells and eosinophils.The objective of the current project is the quantitative assessment of the spatial distribution of immune cells and signaling mediators during a zymosan-induced inflammation. The goal is to identify and define the different microenvironments, which arise during the course of an inflammation. In this regard, the MELC data will be analyzed to describe immune cell localization and their neighboring cells using a machine learning approach. To investigate the functional relationships between the different microenvironments, the effect of region-selective interventions (G2A knockout mice, eosinophil depletion and pharmacological intervention) on the inflammatory architecture will be tested, validated by FACS and compared to pathophysiological effects, such as edema formation and nociceptive behavior. Also, a special focus will be put on the identification of cells with an antiinflammatory phenotype in early states of the inflammation and the characterization of their role in the formation of the antiinflammatory region.

• DFG Programme: Research Grants