P6 - Novel functions of polysialic acid in kidney and immune cell development

Polysialic acid (polySia) is a unique and dynamically regulated posttranslational modification on a limited number of proteins involved in the control of cell-cell interactions and cell migration. While well known to support cell plasticity by stereo-chemical means, recent studies demonstrate that polySia binds to soluble proteins, e.g. chemokines or neurotropic factors and thus assists the build-up of instructive gradients. PolySia-negative mice show defects in kidney vasculogenesis similar to mice with destroyed VEGF-A and CXCL12/CXCR4 signaling. Since CXCL12 is critical for controlling cell migration processes that accompany development of immune homeostasis and since polySia-deficient mice exhibit increased contact hypersensitivity, we hypothesize that polySia contributes to the sensing of VEGF-A and CXCL12 signals. Here, we will investigate the topology and dynamics of polySia expression during kidney and lymphoid organ organogenesis as well as plasma cell differentiation. We commence studies on the cellular and molecular mechanisms that enable the functional crosstalk. Results will advance our understanding on the role of polySia in steering and interpreting the intricate network of informational cues that guide kidney and lymphoid organ development.