Extracellular Vesicles and Immune Signaling

Our group measured the evolution of EV subtypes in stored blood and determined the influence of blood manufacturing method on EV generation. In addition, we found that EVs in blood interact primarily with monocytes, inducing a pro-inflammatory response in these cells. The immunologically active portion of EVs was contained in the smaller, exosome fraction. More recent studies of critically ill subjects has led to the development of a model whereby EVs generated by endothelial cells, granulocytes, and platelets activate monocytes, which can lead to increased tissue damage.

Our group has also made significant contributions into methods to quantitate and characterize EVs by flow cytometry. We defined methods to avoid contamination by pre-filtering fluorochrome-conjugated antibodies to remove aggregates and to decrease background signal through washing and gating strategies. These techniques are now being applied to subjects in clinical trials of blood transfusion to detect immune modulation induced by transfusion.

Selected Publications:

Spinella PC, Sparrow RL, Hess JR, Norris PJ. Properties of stored RBCs: Understanding immune and vascular reactivity. Transfusion 51(4):894-900 PMC3081134 (2011).

Danesh A, Inglis HC, Jackman RP, Wu S, Deng X, Muench MO, Heitman JW, Norris PJ. Exosomes from RBC units bind to monocytes and induce pro-inflammatory cytokines, boosting T cell responses in vitro. Blood 123(5):687-96 PMC3907755 (2014).

Inglis HC, Danesh A, Shah A, Lacroix J, Spinella PC, Norris PJ. Techniques to improve detection and analysis of extracellular vesicles using flow cytometry. Cytometry A 87(11):1052-63 PMC4876854 (2015).

Inglis HC, Norris PJ, Danesh A. Techniques for the analysis of extracellular vesicles using flow cytometry. J Vis Exp (97) (2015).

Bakkour S, Acker JP, Chafets DM, Inglis HC, Norris PJ, Lee TH, Busch MP. Manufacturing method affects mitochondrial DNA release and microparticle composition in stored red blood cells. Vox Sang 111(1):22-32 (2016).