title: Flunarizine suppresses endothelial Angiopoietin-2 in a calcium - dependent fashion in sepsis.
abstract: Sepsis is a life-threatening organ dysfunction caused by a dysregulated host response to an infection leading to systemic inflammation and endothelial barrier breakdown. The vascular-destabilizing factor Angiopoietin-2 (Angpt-2) has been implicated in these processes in humans. Here we screened in an unbiased approach FDA-approved compounds with respect to Angpt-2 suppression in endothelial cells (ECs) in vitro. We identified Flunarizine - a well-known anti-migraine calcium channel (CC) blocker - being able to diminish intracellular Angpt-2 protein in a time- and dose-dependent fashion thereby indirectly reducing the released protein. Moreover, Flunarizine protected ECs from TNFα-induced increase in Angpt-2 transcription and vascular barrier breakdown. Mechanistically, we could exclude canonical Tie2 signalling being responsible but found that three structurally distinct T-type - but not L-type - CC blockers can suppress Angpt-2. Most importantly, experimental increase in intracellular calcium abolished Flunarizine's effect. Flunarizine was also able to block the injurious increase of Angpt-2 in murine endotoxemia in vivo. This resulted in reduced pulmonary adhesion molecule expression (intercellular adhesion molecule-1) and tissue infiltration of inflammatory cells (Gr-1). Our finding could have therapeutic implications as side effects of Flunarizine are low and specific sepsis therapeutics that target the dysregulated host response are highly desirable.
authors.affiliation: Division of Nephrology and Hypertension, Hannover Medical School, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Retzlaff
authors.affiliation: Division of Nephrology and Hypertension, Hannover Medical School, Germany.
authors.forename: Kristina
authors.initials: K
authors.lastname: Thamm
authors.affiliation: Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Vascular Biology Research, Boston, MA, USA.
authors.forename: Chandra C
authors.initials: CC
authors.lastname: Ghosh
authors.affiliation: Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Ziegler
authors.affiliation: Division of Nephrology and Hypertension, Hannover Medical School, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Haller
authors.affiliation: Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Vascular Biology Research, Boston, MA, USA.
authors.forename: Samir M
authors.initials: SM
authors.lastname: Parikh
authors.affiliation: Division of Nephrology and Hypertension, Hannover Medical School, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: David
mesh_terms: D042702:Angiopoietin-2 / Q000096:biosynthesis*; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D019446:Endotoxemia / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D005444:Flunarizine / Q000494:pharmacology*; D061307:Human Umbilical Vein Endothelial Cells / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D051379:Mice; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: C586513:ANGPT2 protein, human; D042702:Angiopoietin-2; D005444:Flunarizine; D002118:Calcium