title: Mesenchymal stem cells, used as bait, disclose tissue binding sites: a tool in the search for the niche?
abstract: We developed an ex vivo approach characterizing renal mesenchymal stem cell (MSC) adhesion to kidney sections. Specificity of MSC adhesion was confirmed by demonstrating a) 3T3 cells displayed 10-fold lower adhesion, and b) MSC adhesion was CXCR4/stromal-derived factor-1 (SDF-1)-dependent. MSC adhesion was asymmetrical, with postischemic sections exhibiting more than twofold higher adhesion than controls, and showed preference to perivascular areas. Pretreating kidney sections with cyclic arginine-glycine-aspartic acid peptide resulted in increased MSC adhesion (by displacing resident cells), whereas blockade of CXCR4 with AMD3100 and inhibition of alpha4beta1(VLA4) integrin or vascular cellular adhesion molecule-1, reduced adhesion. The difference between adhered cells under cyclic arginine-glycine-aspartic acid peptide-treated and control conditions reflected prior occupancy of binding sites with endogenous cells. The AMD3100-inhibitable fraction of adhesion reflected CXCR4-dependent adhesion, whereas maximal adhesion was interpreted as kidney MSC-lodging capacity. MSC obtained from mice overexpressing caveolin-1 exhibited more robust adhesion than those obtained from knockout animals, consistent with CXCR4 dimerization in caveolae. These data demonstrate a) CXCR4/SDF-1-dependent adhesion increases in ischemia; b) CXCR4/SDF-1 activation is dependent on MSC surface caveolin-1; and c) occupancy of MSC binding sites is decreased, while d) capacity of MSC binding sites is expanded in postischemic kidneys. In conclusion, we developed a cell-bait strategy to unmask renal stem cell binding sites, which may potentially shed light on the MSC niche(s) and its characteristics.
authors.affiliation: Department of Medicine, New York Medical College, Renal Research Institute, Valhalla, NY 10595, USA.
authors.forename: Brian B
authors.initials: BB
authors.lastname: Ratliff
authors.forename: Nandita
authors.initials: N
authors.lastname: Singh
authors.forename: Kaoru
authors.initials: K
authors.lastname: Yasuda
authors.forename: Hyeong-Cheon
authors.initials: HC
authors.lastname: Park
authors.forename: Francesco
authors.initials: F
authors.lastname: Addabbo
authors.forename: Tammer
authors.initials: T
authors.lastname: Ghaly
authors.forename: Maharshi
authors.initials: M
authors.lastname: Rajdev
authors.forename: Jean-Francois
authors.initials: JF
authors.lastname: Jasmin
authors.forename: Matthew
authors.initials: M
authors.lastname: Plotkin
authors.forename: Michael P
authors.initials: MP
authors.lastname: Lisanti
authors.forename: Michael S
authors.initials: MS
authors.lastname: Goligorsky
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001665:Binding Sites; D051242:Caveolin 1 / Q000378:metabolism; D002448:Cell Adhesion; D002478:Cells, Cultured; D054377:Chemokine CXCL12 / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology; D016023:Integrins / Q000378:metabolism; D007668:Kidney / Q000166:cytology*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000502:physiology*; D051379:Mice; D008822:Mice, Transgenic; D019718:Receptors, CXCR4 / Q000378:metabolism; D055153:Stem Cell Niche
chemical_list: D051242:Caveolin 1; D054377:Chemokine CXCL12; C515256:Cxcl12 protein, mouse; D016023:Integrins; D019718:Receptors, CXCR4