Florian Puhm1,2, Taras Afonyushkin1,2, Ulrike Resch3, Georg Obermayer1,2, Manfred Rohde4, Thomas Penz2, Michael Schuster2, Gabriel Wagner1, Andre F Rendeiro2, Imene Melki5, Christoph Kaun6, Johann Wojta6,7,8, Christoph Bock1,2, Bernd Jilma9, Nigel Mackman10, Eric Boilard5, Christoph J Binder1,2. 1. From the Department of Laboratory Medicine (F.P., T.A., G.O., G.W., C.B., C.J.B.). 2. Research Center for Molecular Medicine (CeMM) of the Austrian Academy of Sciences, Vienna (F.P., T.A., G.O., T.P., M.S., A.F.R., C.B., C.J.B.). 3. Center of Physiology and Pharmacology (U.R.). 4. Central Facility for Microscopy, Helmholtz Centre for Infection Research, Braunschweig, Germany (M.R.). 5. Department of Infectious Diseases and Immunity, Faculty of Medicine, Centre de Recherche du Centre Hospitalier Universitaire de Québec, Université Laval, Quebec City, Canada (I.M., E.B.). 6. Department of Internal Medicine II (C.K., J.W.). 7. Core Facilities (J.W.). 8. Ludwig Boltzmann Cluster for Cardiovascular Research, Vienna, Austria (J.W.). 9. Department of Clinical Pharmacology (B.J.), Medical University of Vienna, Austria. 10. Division of Hematology and Oncology, Department of Medicine, University of North Carolina at Chapel Hill (N.M.).
Abstract
RATIONALE: Extracellular vesicles, including microvesicles, are increasingly recognized as important mediators in cardiovascular disease. The cargo and surface proteins they carry are considered to define their biological activity, including their inflammatory properties. Monocyte to endothelial cell signaling is a prerequisite for the propagation of inflammatory responses. However, the contribution of microvesicles in this process is poorly understood. OBJECTIVE: To elucidate the mechanisms by which microvesicles derived from activated monocytic cells exert inflammatory effects on endothelial cells. METHODS AND RESULTS: LPS (lipopolysaccharide)-stimulated monocytic cells release free mitochondria and microvesicles with mitochondrial content as demonstrated by flow cytometry, quantitative polymerase chain reaction, Western Blot, and transmission electron microscopy. Using RNAseq analysis and quantitative reverse transcription-polymerase chain reaction, we demonstrated that both mitochondria directly isolated from and microvesicles released by LPS-activated monocytic cells, as well as circulating microvesicles isolated from volunteers receiving low-dose LPS-injections, induce type I IFN (interferon), and TNF (tumor necrosis factor) responses in endothelial cells. Depletion of free mitochondria significantly reduced the ability of these microvesicles to induce type I IFN and TNF-dependent genes. We identified mitochondria-associated TNFα and RNA from stressed mitochondria as major inducers of these responses. Finally, we demonstrated that the proinflammatory potential of microvesicles and directly isolated mitochondria were drastically reduced when they were derived from monocytic cells with nonrespiring mitochondria or monocytic cells cultured in the presence of pyruvate or the mitochondrial reactive oxygen species scavenger MitoTEMPO. CONCLUSIONS: Mitochondria and mitochondria embedded in microvesicles constitute a major subset of extracellular vesicles released by activated monocytes, and their proinflammatory activity on endothelial cells is determined by the activation status of their parental cells. Thus, mitochondria may represent critical intercellular mediators in cardiovascular disease and other inflammatory settings associated with type I IFN and TNF signaling.
RATIONALE: Extracellular vesicles, including microvesicles, are increasingly recognized as important mediators in cardiovascular disease. The cargo and surface proteins they carry are considered to define their biological activity, including their inflammatory properties. Monocyte to endothelial cell signaling is a prerequisite for the propagation of inflammatory responses. However, the contribution of microvesicles in this process is poorly understood. OBJECTIVE: To elucidate the mechanisms by which microvesicles derived from activated monocytic cells exert inflammatory effects on endothelial cells. METHODS AND RESULTS:LPS (lipopolysaccharide)-stimulated monocytic cells release free mitochondria and microvesicles with mitochondrial content as demonstrated by flow cytometry, quantitative polymerase chain reaction, Western Blot, and transmission electron microscopy. Using RNAseq analysis and quantitative reverse transcription-polymerase chain reaction, we demonstrated that both mitochondria directly isolated from and microvesicles released by LPS-activated monocytic cells, as well as circulating microvesicles isolated from volunteers receiving low-dose LPS-injections, induce type I IFN (interferon), and TNF (tumor necrosis factor) responses in endothelial cells. Depletion of free mitochondria significantly reduced the ability of these microvesicles to induce type I IFN and TNF-dependent genes. We identified mitochondria-associated TNFα and RNA from stressed mitochondria as major inducers of these responses. Finally, we demonstrated that the proinflammatory potential of microvesicles and directly isolated mitochondria were drastically reduced when they were derived from monocytic cells with nonrespiring mitochondria or monocytic cells cultured in the presence of pyruvate or the mitochondrial reactive oxygen species scavenger MitoTEMPO. CONCLUSIONS: Mitochondria and mitochondria embedded in microvesicles constitute a major subset of extracellular vesicles released by activated monocytes, and their proinflammatory activity on endothelial cells is determined by the activation status of their parental cells. Thus, mitochondria may represent critical intercellular mediators in cardiovascular disease and other inflammatory settings associated with type I IFN and TNF signaling.
Authors: Gentaro Ikeda; Michelle R Santoso; Yuko Tada; Albert M Li; Evgeniya Vaskova; Ji-Hye Jung; Connor O'Brien; Elizabeth Egan; Jiangbin Ye; Phillip C Yang Journal: J Am Coll Cardiol Date: 2021-03-02 Impact factor: 24.094
Authors: E Letsiou; L G Teixeira Alves; D Fatykhova; M Felten; T J Mitchell; H C Müller-Redetzky; A C Hocke; M Witzenrath Journal: Sci Rep Date: 2021-05-05 Impact factor: 4.379