The Human Innate Immune Protein Calprotectin Elicits a Multi-Metal Starvation Response in Pseudomonas Aeruginosa

The study investigated the effects of the innate immune protein calprotectin (CP) on the opportunistic pathogen Pseudomonas aeruginosa, focusing on how CP induces a multi-metal starvation response. CP was found to sequester essential metals like iron (Fe), zinc (Zn), and manganese (Mn), which are crucial for pathogen growth. The research revealed that CP triggered an incomplete Fe-starvation response but a more complete Zn-starvation response, leading to increased expression of Zn transporters and Zn-independent proteins. Additionally, CP induced the expression of membrane-modifying proteins, enhancing resistance to polymyxin B. This response involved both single and multi-metal starvation, affecting factors related to the pathogen's virulence potential and providing insights into the interaction between P. aeruginosa and the host's immune system.