Jan R Thiele1, Jonathon Habersberger1, David Braig1, Yvonne Schmidt1, Kurt Goerendt1, Valentin Maurer1, Holger Bannasch1, Amelie Scheichl1, Kevin J Woollard1, Ernst von Dobschütz1, Frank Kolodgie1, Renu Virmani1, G Bjoern Stark1, Karlheinz Peter1, Steffen U Eisenhardt2. 1. From the University of Freiburg Medical Center, Department of Plastic and Hand Surgery (J.R.T., D.B., Y.S., K.G., V.M., H.B., G.B.S., S.U.E.) and Section of Endocrine Surgery, Clinic of General, Visceral and Thoracic Surgery, Academic Teaching Hospital University of Hamburg (E.v.D.), Reinbeck, Germany; Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (J.H., A.S., K.P.); Imperial College London, Department of Medicine, London, United Kingdom (K.J.W.); and CVPath Institute, Gaithersburg, MD (F.K., R.V.). 2. From the University of Freiburg Medical Center, Department of Plastic and Hand Surgery (J.R.T., D.B., Y.S., K.G., V.M., H.B., G.B.S., S.U.E.) and Section of Endocrine Surgery, Clinic of General, Visceral and Thoracic Surgery, Academic Teaching Hospital University of Hamburg (E.v.D.), Reinbeck, Germany; Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia (J.H., A.S., K.P.); Imperial College London, Department of Medicine, London, United Kingdom (K.J.W.); and CVPath Institute, Gaithersburg, MD (F.K., R.V.). steffen.eisenhardt@uniklinik-freiburg.de.
Abstract
BACKGROUND: The relevance of the dissociation of circulating pentameric C-reactive protein (pCRP) to its monomeric subunits (mCRP) is poorly understood. We investigated the role of conformational C-reactive protein changes in vivo. METHODS AND RESULTS: We identified mCRP in inflamed human striated muscle, human atherosclerotic plaque, and infarcted myocardium (rat and human) and its colocalization with inflammatory cells, which suggests a general causal role of mCRP in inflammation. This was confirmed in rat intravital microscopy of lipopolysaccharide-induced cremasteric muscle inflammation. Intravenous pCRP administration significantly enhanced leukocyte rolling, adhesion, and transmigration via localized dissociation to mCRP in inflamed but not noninflamed cremaster muscle. This was confirmed in a rat model of myocardial infarction. Mechanistically, this process was dependent on exposure of lysophosphatidylcholine on activated cell membranes, which is generated after phospholipase A2 activation. These membrane changes could be visualized intravitally on endothelial cells, as could the colocalized mCRP generation. Blocking of phospholipase A2 abrogated C-reactive protein dissociation and thereby blunted the proinflammatory effects of C-reactive protein. Identifying the dissociation process as a therapeutic target, we stabilized pCRP using 1,6-bis(phosphocholine)-hexane, which prevented dissociation in vitro and in vivo and consequently inhibited the generation and proinflammatory activity of mCRP; notably, it also inhibited mCRP deposition and inflammation in rat myocardial infarction. CONCLUSIONS: These results provide in vivo evidence for a novel mechanism that localizes and aggravates inflammation via phospholipase A2-dependent dissociation of circulating pCRP to mCRP. mCRP is proposed as a pathogenic factor in atherosclerosis and myocardial infarction. Most importantly, the inhibition of pCRP dissociation represents a promising, novel anti-inflammatory therapeutic strategy.
BACKGROUND: The relevance of the dissociation of circulating pentameric C-reactive protein (pCRP) to its monomeric subunits (mCRP) is poorly understood. We investigated the role of conformational C-reactive protein changes in vivo. METHODS AND RESULTS: We identified mCRP in inflamed human striated muscle, humanatherosclerotic plaque, and infarcted myocardium (rat and human) and its colocalization with inflammatory cells, which suggests a general causal role of mCRP in inflammation. This was confirmed in rat intravital microscopy of lipopolysaccharide-induced cremasteric muscle inflammation. Intravenous pCRP administration significantly enhanced leukocyte rolling, adhesion, and transmigration via localized dissociation to mCRP in inflamed but not noninflamed cremaster muscle. This was confirmed in a rat model of myocardial infarction. Mechanistically, this process was dependent on exposure of lysophosphatidylcholine on activated cell membranes, which is generated after phospholipase A2 activation. These membrane changes could be visualized intravitally on endothelial cells, as could the colocalized mCRP generation. Blocking of phospholipase A2 abrogated C-reactive protein dissociation and thereby blunted the proinflammatory effects of C-reactive protein. Identifying the dissociation process as a therapeutic target, we stabilized pCRP using 1,6-bis(phosphocholine)-hexane, which prevented dissociation in vitro and in vivo and consequently inhibited the generation and proinflammatory activity of mCRP; notably, it also inhibited mCRP deposition and inflammation in ratmyocardial infarction. CONCLUSIONS: These results provide in vivo evidence for a novel mechanism that localizes and aggravates inflammation via phospholipase A2-dependent dissociation of circulating pCRP to mCRP. mCRP is proposed as a pathogenic factor in atherosclerosis and myocardial infarction. Most importantly, the inhibition of pCRP dissociation represents a promising, novel anti-inflammatory therapeutic strategy.
Authors: Ursula M Schick; Paul L Auer; Joshua C Bis; Honghuang Lin; Peng Wei; Nathan Pankratz; Leslie A Lange; Jennifer Brody; Nathan O Stitziel; Daniel S Kim; Christopher S Carlson; Myriam Fornage; Jeffery Haessler; Li Hsu; Rebecca D Jackson; Charles Kooperberg; Suzanne M Leal; Bruce M Psaty; Eric Boerwinkle; Russell Tracy; Diego Ardissino; Svati Shah; Cristen Willer; Ruth Loos; Olle Melander; Ruth Mcpherson; Kees Hovingh; Muredach Reilly; Hugh Watkins; Domenico Girelli; Pierre Fontanillas; Daniel I Chasman; Stacey B Gabriel; Richard Gibbs; Deborah A Nickerson; Sekar Kathiresan; Ulrike Peters; Josée Dupuis; James G Wilson; Stephen S Rich; Alanna C Morrison; Emelia J Benjamin; Myron D Gross; Alex P Reiner Journal: Hum Mol Genet Date: 2014-09-03 Impact factor: 6.150