Beschreibung:
<jats:title>Abstract</jats:title>
<jats:p>Calcium and phosphate are well known as the main minerals in bone ossification. But they also have an immunomodulatory potential as components of calciprotein particles. Such particles precipitate spontaneously in body fluids if the calcium and phosphate homeostasis is disturbed. An abnormally increased mineral load could lead to soft tissue calcification. In our study we investigated the cellular response of freshly isolated peripheral blood monocytes in serum-containing medium under precipitating (high calcium and high phosphate content) conditions. Using dynamic mass redistribution analyses with the EPIC® system and IL-1β measurements as readout, we identified phosphate as a necessary co-modulator of calcium-triggered overall cellular responses and NLRP3 inflammasome activation. Moreover, flow cytometry and ImageStream® analyses revealed the uptake of spontaneously formed nanoparticles under stimulating conditions, which depends on the activation of the G protein-coupled receptor Calcium-sensing receptor (CaSR). Our study unraveled a GPCR-mediated mechanism by which monocytes detect imbalances in calcium phosphate homeostasis in the extracellular space resulting in an enormous pro-inflammatory cellular response.</jats:p>