title: Tissue kallikrein is essential for invasive capacity of circulating proangiogenic cells.
abstract: BACKGROUND
  Homing of proangiogenic cells (PACs) is guided by chemoattractants and requires proteases to disrupt the extracellular matrix. The possibility that PAC recruitment involves an interaction between proteases and chemotactic factor receptors remains largely unexplored.
  
  
  OBJECTIVE
  To determine the role of human tissue kallikrein (hK1) in PAC invasion and its dependency on kinin receptor signaling.
  
  
  RESULTS
  Human mononuclear cells (MNCs) and culture-selected PACs express and release mature hK1 protein. HK1 gene (KLK1) silencing reduced PACs migratory, invasive, and proangiogenic activities. KLK1-knockout mouse bone marrow-derived MNCs showed similar impairments and were unable to support reparative angiogenesis in a mouse model of peripheral ischemia. Conversely, adenovirus-mediated KLK1 (Ad.KLK1) gene transfer enhanced PAC-associated functions, whereas the catalytically inactive variant R53H-KLK1 was ineffective. HK1-induced effects are mediated by a kinin B(2) receptor (B(2)R)-dependent mechanism involving inducible nitric oxide synthase and metalloproteinase-2 (MMP2). Lower hK1 protein levels were observed in PACs from type 2 diabetic (T2D) patients, whereas KLK1 mRNA levels were similar to those of healthy subjects, suggesting a post-transcriptional defect. Furthermore, B(2)R is normally expressed on T2D-PACs but remains uncoupled from downstream signaling. Importantly, whereas Ad.KLK1 alone could not restore T2D-PAC invasion capacity, combined KLK1 and B(2)R expression rescued the diabetic phenotype.
  
  
  CONCLUSIONS
  This study reveals new interactive components of the PACs invasive machinery, acting via protease- and kinin receptor-dependent mechanisms.
authors.affiliation: Chair of Experimental Cardiovascular Medicine, University of Bristol, Bristol BS28HW, United Kingdom.
authors.forename: Gaia
authors.initials: G
authors.lastname: Spinetti
authors.forename: Orazio
authors.initials: O
authors.lastname: Fortunato
authors.forename: Daniela
authors.initials: D
authors.lastname: Cordella
authors.forename: Paola
authors.initials: P
authors.lastname: Portararo
authors.forename: Nicolle
authors.initials: N
authors.lastname: Kränkel
authors.forename: Rajesh
authors.initials: R
authors.lastname: Katare
authors.forename: Graciela B
authors.initials: GB
authors.lastname: Sala-Newby
authors.forename: Christine
authors.initials: C
authors.lastname: Richer
authors.forename: Marie-Pascale
authors.initials: MP
authors.lastname: Vincent
authors.forename: Francois
authors.initials: F
authors.lastname: Alhenc-Gelas
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Tonolo
authors.forename: Sara
authors.initials: S
authors.lastname: Cherchi
authors.forename: Costanza
authors.initials: C
authors.lastname: Emanueli
authors.forename: Paolo
authors.initials: P
authors.lastname: Madeddu
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D016022:Case-Control Studies; D002465:Cell Movement / Q000502:physiology*; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism / Q000473:pathology; D015536:Down-Regulation; D005260:Female; D006614:Hindlimb / Q000098:blood supply; D006801:Humans; D007511:Ischemia / Q000378:metabolism; D007610:Kallikreins / Q000235:genetics / Q000378:metabolism*; D007705:Kinins / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000166:cytology* / Q000378:metabolism*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008875:Middle Aged; D023421:Models, Animal; D018919:Neovascularization, Physiologic / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D043782:Receptor, Bradykinin B2 / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: D007705:Kinins; D012333:RNA, Messenger; D043782:Receptor, Bradykinin B2; D019001:Nitric Oxide Synthase; D007610:Kallikreins; D020778:Matrix Metalloproteinase 2