DAMP activation and orchestration of cytokine storm by the cold shock protein

• Applicant: Dr. Sabine Brandt
• Subject Area: Nephrology
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 517830864

Acute kidney injury is a common sequela of diseases associated with blood pressure decrements, such as septicemia or hypoxia. Dead cells and activated tissue resident cells trigger an immune response with subsequent organ failure that represents a complex intermingled process. The focus of this application is to elucidate common underlying mechanisms and cell responses. In sepsis, soluble factors released by bacteria into the blood, circulate as pathogen-associated molecular patterns (PAMPs) and incite local and systemic inflammatory responses. PAMPs are recognized by pattern recognizing receptors (PRRs) and activate NF-kB signaling, leading to increased expression of damage-associated molecular patterns (DAMPs). DAMPs are released from the nuclear, mitochondrial, or cytoplasmic compartments following inflammasome activation, pyroptosis, necroptosis, or by exosomes. DAMPs initiate and sustain a noninfectious inflammatory response that is associated with systemic inflammation, organ damage, and cell death. Y-box binding protein-1 (YB-1) is a mediator of local and systemic inflammatory responses. Inflammatory stimuli, such as LPS and hypoxia, trigger intracellular upregulation as well as YB 1 secretion. Wild type and whole body Ybx1 knockout mice (Ybx1DeltaRosaCreERT) were challenged with LPS. While the majority (70%) of wild type mice die, 75% of Ybx1 knockout mice survive. Changes in the inflammatory milieu show that YB-1 is not only present in the secretome but also regulates the composition. These findings form the basis for the present work program, in which the role of YB-1 in DAMP activation and orchestration of cytokine storm will be investigated. The following questions will be addressed: (i) Which DAMPs are regulated by YB-1 in a cell-specific manner? Comparative studies of secretomes in different cell types of wild type and Ybx1 knockout mice will be performed. (ii) What is the contribution of YB-1 for DAMP-dependent cell-cell communication in in vitro models? (iii) What is the in vivo relevance of YB-1 for damage perpetuation and protective effects in an ischemia/reperfusion model. Chimeric bone marrow animals with YB-1 wild type and YB-1-deficient cells will be generated. The secretome data will be analyzed for cell-specific protective factors as well as damage markers. These data will be used to design therapeutic strategies. Two approaches are envisioned: 1. Blockade of LPS and hypoxia-induced damage markers (DAMPs, cytokines) by inhibiting YB-1 activities and 2. To introduce the identified protective factors as an intervention strategy. In summary, the project proposal will expand our understanding of inflammatory secretomes, with a focus on a centrally acting molecule of the cold shock protein family. The results will be translated into intervention strategies to ameliorate acute kidney injury and initiate tissue regeneration.

• DFG Programme: Research Grants