title: Concentrative uptake of cyclic ADP-ribose generated by BST-1+ stroma stimulates proliferation of human hematopoietic progenitors.
abstract: Cyclic ADP-ribose (cADPR) is an intracellular calcium mobilizer generated from NAD(+) by the ADP-ribosyl cyclases CD38 and BST-1. cADPR, both exogenously added and paracrinally produced by a CD38(+) feeder layer, has recently been demonstrated to stimulate the in vitro proliferation of human hemopoietic progenitors (HP) and also the in vivo expansion of hemopoietic stem cells. The low density of BST-1 expression on bone marrow (BM) stromal cells and the low specific activity of the enzyme made it unclear whether cADPR generation by a BST-1(+) stroma could stimulate HP proliferation in the BM microenvironment. We developed and characterized two BST-1(+) stromal cell lines, expressing an ectocellular cyclase activity similar to that of BST-1(+) human mesenchymal stem cells, the precursors of BM stromal cells. Long term co-culture of cord blood-derived HP over these BST-1(+) feeders determined their expansion. Influx of paracrinally generated cADPR into clonogenic HP was mediated by a concentrative, nitrobenzylthioinosine- and dipyridamole-inhibitable nucleoside transporter, this providing a possible explanation to the effectiveness of the hormone-like concentrations of the cyclic nucleotide measured in the medium conditioned by BST-1(+) feeders. These results suggest that the BST-1-catalyzed generation of extracellular cADPR, followed by the concentrative uptake of the cyclic nucleotide by HP, may be physiologically relevant in normal hemopoiesis.
authors.affiliation: Department of Hematology, 2nd Division, Pad.5, S. Martino Hospital, Largo R. Benzi 10, 16132 Genova, Italy.
authors.forename: Marina
authors.initials: M
authors.lastname: Podestà
authors.forename: Federica
authors.initials: F
authors.lastname: Benvenuto
authors.forename: Anna
authors.initials: A
authors.lastname: Pitto
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Figari
authors.forename: Andrea
authors.initials: A
authors.lastname: Bacigalupo
authors.forename: Santina
authors.initials: S
authors.lastname: Bruzzone
authors.forename: Lucrezia
authors.initials: L
authors.lastname: Guida
authors.forename: Luisa
authors.initials: L
authors.lastname: Franco
authors.forename: Laura
authors.initials: L
authors.lastname: Paleari
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Bodrato
authors.forename: Cesare
authors.initials: C
authors.lastname: Usai
authors.forename: Antonio
authors.initials: A
authors.lastname: De Flora
authors.forename: Elena
authors.initials: E
authors.lastname: Zocchi
mesh_terms: D016475:3T3 Cells; D036541:ADP-ribosyl Cyclase / Q000235:genetics / Q000378:metabolism*; D051997:ADP-ribosyl Cyclase 1; D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D018952:Antigens, CD34 / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D019556:COS Cells; D002118:Calcium / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D018920:Coculture Techniques; D036563:Cyclic ADP-Ribose / Q000378:metabolism*; D005434:Flow Cytometry; D058851:GPI-Linked Proteins; D006412:Hematopoietic Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008562:Membrane Glycoproteins; D051379:Mice; D009243:NAD / Q000378:metabolism; D033703:Nucleoside Transport Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; D018952:Antigens, CD34; D058851:GPI-Linked Proteins; D008562:Membrane Glycoproteins; D033703:Nucleoside Transport Proteins; D009243:NAD; D036563:Cyclic ADP-Ribose; D036541:ADP-ribosyl Cyclase; C087521:ADP-ribosyl cyclase 2; C498154:CD38 protein, human; C498155:Cd38 protein, mouse; D051997:ADP-ribosyl Cyclase 1; D002118:Calcium