A6: Role of exosomes in trauma-induced extravasation of neutrophil granulocytes

PIs: S. Paschke, T. Seufferlein

Neutrophils are critical regulators of the trauma response. We have previously shown that the actin cytoskeleton is important for deformability and transendothelial passage of neutrophils, regulated by Protein Kinase D (PKD). The actin cytoskeleton is also vital for endothelial barrier stability and exosome secretion. Our preliminary data indicate that trauma drives barrier breakdown and fosters exosome release thereby boosting barrier dysfunction. Interestingly, PKD has also a major role in exosome secretion and endothelial barrier stability. Thus, it is the objective of project A06 to investigate how quantitative and qualitative modulation of exosome secretion, e.g. by PKD, affects endothelial and epithelial barrier stability and may improve trauma outcome. We hypothesize that trauma enhances exosome secretion to boost disruption of endothelial and epithelial barriers. Thus, we will investigate how exosomes released after blunt chest trauma w/wo hemorrhagic shock (HS), polytrauma w/wo HS (cooperation project A01) or from a pig hemorrhagic shock model (project B03) will impact on endothelial barrier stability in vitro and in a 3D-lung barrier model (A05). We will also elucidate whether quantitative and qualitative modulation of exosome secretion after thorax trauma affects the integrity of endogenous barriers. To this end we will assess how modulation of exosome release and in particular cargo content in blunt chest trauma mice, e.g. by PKD inhibition will impact on endothelial/alveolar barrier stability using in vitro barrier assays and mouse models (cooperation projectA01). We further propose to investigate if exosomal microRNAs modulate endogenous barrier integrity after thorax trauma. Exosomal microRNAs are important for the education of recipient cells. Utilizing microRNA microarrays we will elucidate which microRNAs are released into exosomes after trauma and how these microRNAs affect barrier stability or inflammatory response. We will further investigate how PKD inhibition impacts on exosome microRNA content and trauma outcome by regulating barrier integrity.

Projektleiter

Dr. med. Stephan Paschke
Zentrum für Chirurgie
Klinik für Allgemein- und Viszeralchirurgie
Albert-Einstein-Allee 23
89081 Ulm
Tel.: +49 731 500 53596
Fax: +49 731 500 53502
stephan.paschke(at)uniklinik-ulm.de
Homepage

Prof. Dr. Thomas Seufferlein
Zentrum für Innere Medizin
Klinik für Innere Medizin I
Albert-Einstein-Allee 23
89081 Ulm
Tel.: +49 731 500 44501
Fax: +49 731 500 44502
thomas.seufferlein(at)uniklinik-ulm.de
Homepage

 

Extravasation (A) and interstitial movement (B) of neutrophils. Both aspects of neutrophil migration require highly dynamic shape changes that require a considerable amount of deformability. The actin filament network is a major compartment of the cytoskeleton in neutrophils and plays an important part in controlling these processes. Protein Kinases D (PKD) family are crucial regulators during the dynamic rearrangement of actin filaments.
Visualisation of the subcortical cytoskeleton by scanning electron microscopy. Inset (A) depicts a human neutrophil. The cell membrane (m) was partially removed to reveal the filamentous cytoskeleton (c) within the subcortical compartment. The filaments are composed of actin as demonstrated in inset (B) by immunogold labelling with an anti-actin antibody (red dots). The scale bars represent 150 nm.