A conformational change in C-Reactive protein enhances leukocyte recruitment and reactive Oxygen species generation in Ischemia/Reperfusion injury
Thiele, Jan R.
Frontiers in Immunology ; 9 (2018). - Art.-Nr. 675. - eISSN 1664-3224
Link zur Originalveröffentlichunghttps://dx.doi.org/10.3389/fimmu.2018.00675
InstitutionenUKU. Institut für Klinische und Experimentelle Trauma-Immunologie
Externe KooperationenRoosevelt University
Baker Heart and Diabetes Institute
DokumentversionVeröffentlichte Version (Verlags-PDF)
Introduction C-reactive protein circulates as a pentameric protein (pCRP). pCRP is a well-established diagnostic marker as plasma levels rise in response to tissue injury and inflammation. We recently described pro-inflammatory properties of CRP, which are mediated by conformational changes from pCRP to bioactive isoforms expressing pro-inflammatory neo-epitopes [pCRP* and monomeric C-reactive protein (mCRP)]. Here, we investigate the role of CRP isoforms in renal ischemia/reperfusion injury (IRI). Methods Rat kidneys in animals with and without intraperitoneally injected pCRP were subjected to IRI by the time of pCRP exposure and were subsequently analyzed for monocyte infiltration, caspase-3 expression, and tubular damage. Blood urea nitrogen (BUN) was analyzed pre-ischemia and post-reperfusion. CRP effects on leukocyte recruitment were investigated via intravital imaging of rat-striated muscle IRI. Localized conformational CRP changes were analyzed by immunohistochemistry using conformation specific antibodies. 1,6-bis(phosphocholine)-hexane (1,6-bisPC), which stabilizes CRP in its native pentameric form was used to validate CRP effects. Leukocyte activation was assessed by quantification of reactive oxygen species (ROS) induction by CRP isoforms ex vivo and in vitro through electron spin resonance spectroscopy. Signaling pathways were analyzed by disrupting lipid rafts with nystatin and subsequent ROS detection. In order to confirm the translational relevance of our findings, biopsies of microsurgical human free tissue transfers before and after IRI were examined by immunofluorescence for CRP deposition and co-localization of CD68+ leukocytes. Results The application of pCRP aggravates tissue damage in renal IRI. 1,6-bisPC reverses these effects via inhibition of the conformational change that leads to exposure of pro-inflammatory epitopes in CRP (pCRP* and mCRP). Structurally altered CRP induces leukocyte–endothelial interaction and induces ROS formation in leukocytes, the latter can be abrogated by blocking lipid raft-dependent signaling pathways with Nystatin. Stabilizing pCRP in its native pentameric state abrogates these pro-inflammatory effects. Importantly, these findings are confirmed in human IRI challenged muscle tissue. Conclusion These results suggest that CRP is a potent modulator of IRI. Stabilizing the native pCRP conformation represents a promising anti-inflammatory therapeutic strategy by attenuation of leukocyte recruitment and ROS formation, the primary pathomechanisms of IRI.
Schlagwörter[GND]: C-reaktives Protein | Leukozyt
[MeSH]: C-reactive protein | Ischemia | Reactive oxygen species | Leukocytes
[Freie Schlagwörter]: therapeutic targets | conformational change | translational medical research | leukocyte recruitment | rat models
[DDC Sachgruppe]: DDC 610 / Medicine & health
LizenzCC BY 4.0 International
DOI & Zitiervorlage
Nutzen Sie bitte diesen Identifier für Zitate & Links: http://dx.doi.org/10.18725/OPARU-40187