Role of galanin on immune cell migration and polarization

The project titled The role of the regulatory peptide galanin on immune cell migration and polarization investigates the communication and interaction between the nervous and immune systems. The exchange of these two systems is essential for a well-functioning organism to be able to adapt to an acute challenge of the body like an infection or a chronic inflammation but also acute or chronic stress. Diverse chemical messengers are responsible for the exchange of information and one group of these messengers are called regulatory peptides. These regulatory peptides are released by nerve cells but also by immune cells and bind to other immune cells to exchange information about the condition of the microenvironment. The regulatory peptide of our interest is named galanin, which can interact with three different surface proteins (also called receptors) of cells to transmit different signals. The involvement of galanin and its receptors in different inflammatory models including psoriasis and colitis has been proven. To date, it is unclear which immune cells mediate the pro- or anti-inflammatory functions of the galanin system during acute/chronic inflammation and homeostasis. Based on the scientific literature and our preliminary data, we hypothesize that galanin induces the production of signaling molecules in immune cells, which are needed to attract other immune cells to the area of inflammation. Furthermore, due to the fact that galanin plays a role in the later stages of inflammation, we hypothesize that galanin affects the activation and polarization of specific immune cells (T cells), which are part of the immune cell memory. In in vitro studies, we will first use primary human immune cells, which will be treated with galanin and the effect of this treatment on the ability to influence immune cell migration will be determined. Furthermore, in mice, which either lack galanin or its receptors in their body, differences in the immune response upon an acute inflammation will be analyzed and compared to the response in wild-type animals. Our studies will reveal which immune cells are a source and a target of galanin and how this systems affects the function of diverse immune cell subpopulations. The results of the study will provide a basis for preclinical studies aimed at the therapeutic application of galanin receptor ligands in certain inflammatory diseases. 1