title: HMGB-1 induces c-kit+ cell microvascular rolling and adhesion via both toll-like receptor-2 and toll-like receptor-4 of endothelial cells.
abstract: High-mobility group box 1 (HMGB-1) is a strong chemo-attractive signal for both inflammatory and stem cells. The aim of this study is to evaluate the mechanisms regulating HMGB-1-mediated adhesion and rolling of c-kit(+)  cells and assess whether toll-like receptor-2 (TLR-2) and toll-like receptor-4 (TLR-4) of endothelial cells or c-kit(+)  cells are implicated in the activation of downstream migration signals to peripheral c-kit(+)  cells. Effects of HMGB-1 on the c-kit(+)  cells/endothelial interaction were evaluated by a cremaster muscle model in wild-type (WT), TLR-2 (-/-) and Tlr4 (LPS-del) mice. The mRNA and protein expression levels of endothelial nitric oxide synthase were determined by quantitative real-time PCR and immunofluorescence staining. Induction of crucial adhesion molecules for rolling and adhesion of stem cells and leukocytes were monitored in vivo and in vitro. Following local HMGB-1 administration, a significant increase in cell rolling was detected (32.4 ± 7.1% in 'WT' versus 9.9 ± 3.2% in 'control', P < 0.05). The number of firmly adherent c-kit(+)  cells was more than 13-fold higher than that of the control group (14.6 ± 5.1 cells/mm(2)  in 'WT' versus 1.1 ± 1.0 cells/mm(2)  in 'control', P < 0.05). In knockout animals, the fraction of rolling cells did not differ significantly from control levels. Firm endothelial adhesion was significantly reduced in TLR-2 (-/-) and Tlr4 (LPS-del) mice compared to WT mice (1.5 ± 1.4 cells/mm(2)  in 'TLR-2 (-/-)' and 2.4 ± 1.4 cells/mm(2)  in 'Tlr4 (LPS-del)' versus 14.6 ± 5.1 cells/mm(2)  in 'WT', P < 0.05). TLR-2 (-/-) and Tlr4 (LPS-del) stem cells in WT mice did not show significant reduction in rolling and adhesion compared to WT cells. HMGB-1 mediates c-kit(+)  cell recruitment via endothelial TLR-2 and TLR-4.
authors.affiliation: Reference and Translation Centre for Cardiac Stem Cell Therapy, Department of Cardiac Surgery, University Rostock, Rostock, Germany.
authors.forename: Dario
authors.initials: D
authors.lastname: Furlani
authors.forename: Peter
authors.initials: P
authors.lastname: Donndorf
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Westien
authors.forename: Murat
authors.initials: M
authors.lastname: Ugurlucan
authors.forename: Erik
authors.initials: E
authors.lastname: Pittermann
authors.forename: Weiwei
authors.initials: W
authors.lastname: Wang
authors.forename: Wenzhong
authors.initials: W
authors.lastname: Li
authors.forename: Brigitte
authors.initials: B
authors.lastname: Vollmar
authors.forename: Gustav
authors.initials: G
authors.lastname: Steinhoff
authors.forename: Alexander
authors.initials: A
authors.lastname: Kaminski
authors.forename: Nan
authors.initials: N
authors.lastname: Ma
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects*; D002465:Cell Movement / Q000187:drug effects; D024243:HMGB1 Protein / Q000378:metabolism* / Q000494:pharmacology; D036904:Leukocyte Rolling / Q000187:drug effects / Q000502:physiology*; D008297:Male; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D055806:Microvessels / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000187:drug effects; D052250:Nitric Oxide Synthase Type III / Q000096:biosynthesis; D019009:Proto-Oncogene Proteins c-kit / Q000502:physiology*; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*
chemical_list: D024243:HMGB1 Protein; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; D019009:Proto-Oncogene Proteins c-kit