title: A novel approach to prevent endothelial hyperpermeability: the Crataegus extract WS® 1442 targets the cAMP/Rap1 pathway.
abstract: Endothelial hyperpermeability followed by edema formation is a hallmark of many severe disorders. Effective drugs directly targeting endothelial barrier function are widely lacking. We hypothesized that the hawthorn (Crataegus spp.) extract WS® 1442, a proven multi-component drug against moderate forms of heart failure, would prevent vascular leakage by affecting endothelial barrier-regulating systems. In vivo, WS® 1442 inhibited the histamine-evoked extravasation of FITC-dextran from mouse cremaster muscle venules. In cultured human endothelial cells, WS® 1442 blocked the thrombin-induced FITC-dextran permeability. By applying biochemical and microscopic techniques, we revealed that WS® 1442 abrogates detrimental effects of thrombin on adherens junctions (vascular endothelial-cadherin), the F-actin cytoskeleton, and the contractile apparatus (myosin light chain). Mechanistically, WS® 1442 inhibited the thrombin-induced rise of intracellular calcium (ratiometric measurement), followed by an inactivation of PKC and RhoA (pulldown assay). Moreover, WS® 1442 increased endothelial cAMP levels (ELISA), which consequently activated PKA and Rap1 (pulldown assay). Utilizing pharmacological inhibitors or siRNA, we found that PKA is not involved in barrier protection, whereas Epac1, Rap1, and Rac1 play a crucial role in the WS® 1442-induced activation of cortactin, which triggers a strong cortical actin rearrangement. In summary, WS® 1442 effectively protects against endothelial barrier dysfunction in vitro and in vivo. It specifically interacts with endothelial permeability-regulating systems by blocking the Ca(2+)/PKC/RhoA and activating the cAMP/Epac1/Rap1 pathway. As a proven safe herbal drug, WS® 1442 opens a novel pharmacological approach to treat hyperpermeability-associated diseases. This in-depth mechanistic work contributes to a better acceptance of this herbal remedy.
authors.affiliation: Department of Pharmacy, Center for Drug Research, Pharmaceutical Biology, University of Munich, Butenandtstr. 5-13, 81377 Munich, Germany.
authors.forename: Martin F
authors.initials: MF
authors.lastname: Bubik
authors.forename: Elisabeth A
authors.initials: EA
authors.lastname: Willer
authors.forename: Peter
authors.initials: P
authors.lastname: Bihari
authors.forename: Guido
authors.initials: G
authors.lastname: Jürgenliemk
authors.forename: Hermann
authors.initials: H
authors.lastname: Ammer
authors.forename: Fritz
authors.initials: F
authors.lastname: Krombach
authors.forename: Stefan
authors.initials: S
authors.lastname: Zahler
authors.forename: Angelika M
authors.initials: AM
authors.lastname: Vollmar
authors.forename: Robert
authors.initials: R
authors.lastname: Fürst
mesh_terms: D022005:Adherens Junctions / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects*; D002478:Cells, Cultured; D051356:Cortactin / Q000378:metabolism; D027825:Crataegus; D000242:Cyclic AMP / Q000378:metabolism*; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology*; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D006801:Humans; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D010936:Plant Extracts / Q000494:pharmacology*; D011493:Protein Kinase C / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D022502:Stress Fibers / Q000187:drug effects; D013917:Thrombin / Q000494:pharmacology; D020827:rap1 GTP-Binding Proteins / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000378:metabolism
chemical_list: D051356:Cortactin; D005419:Flavonoids; D020662:Guanine Nucleotide Exchange Factors; D010936:Plant Extracts; C116122:RAPGEF3 protein, human; C421782:WS 1442; C007145:crataegus extract; D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D013917:Thrombin; D020827:rap1 GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D002118:Calcium