CFU-megakaryocytic progenitors expanded ex vivo from cord blood maintain their in vitro homing potential and express matrix metalloproteinases.
BACKGROUND
In patients transplanted with cord blood (CB), prolonged thrombocytopenia is a major complication. However, this could be alleviated by supplementing the CB graft with ex vivo-expanded megakaryocytic progenitors (CFU-Meg), provided that the homing properties of these cells are not affected negatively by expansion.


RESULTS
We assessed the in vitro homing potential of CFU-Meg progenitors expanded from CB and showed that the combination of thrombopoietin (TPO) with interleukin-3 (IL-3) used for expansion not only results in optimal proliferation of CFU-Meg but also protects these cells from apoptosis. Moreover, we found that ex vivo-expanded CFU-Meg maintained expression of the CXCR4 receptor throughout a 9-day culture and were chemoattracted towards a stromal cell-derived factor-1 (SDF-1) gradient. They also expressed matrix metalloproteinase-9 (MMP-9) and membrane-type (MT) 1-MMP, and transmigrated across the reconstituted basement membrane Matrigel. Finally, we observed that SDF-1 up-regulated the expression of both MMP-9 and MT1-MMP in CB CD34(+) cells and ex vivo-expanded CFU-Meg.


CONCLUSIONS
We suggest that CB-expanded CFU-Meg, in particular those from day 3 of expansion, when their proliferation and in vitro homing potential are maximal, could be employed to supplement CB grafts and speed up platelet recovery in transplant recipients.
Shirvaikar
N
N
Canadian Blood Services, Research and Development, Edmonton, Alberta, Canada.
Reca
R
R
Jalili
A
A
Marquez-Curtis
L
L
Lee
S Fong
SF
Ratajczak
M Z
MZ
Janowska-Wieczorek
A
A
D018952:Antigens, CD34 / Q000378:metabolism; D002392:Catechin / Q000031:analogs & derivatives / Q000494:pharmacology; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D054377:Chemokine CXCL12 / Q000378:metabolism; D002630:Chemotactic Factors / Q000494:pharmacology; D002633:Chemotaxis / Q000187:drug effects; D003094:Collagen / Q000378:metabolism; D003114:Colony-Forming Units Assay; D004338:Drug Combinations; D005312:Fetal Blood / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D006801:Humans; D007377:Interleukin-3 / Q000494:pharmacology; D007700:Kinetics; D007797:Laminin / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism*; D008533:Megakaryocytes / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology; D040201:Platelet Membrane Glycoprotein IIb / Q000378:metabolism; D011509:Proteoglycans / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000378:metabolism; D013234:Stem Cells / Q000166:cytology* / Q000187:drug effects; D013926:Thrombopoietin / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
D018952:Antigens, CD34; C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D002630:Chemotactic Factors; D004338:Drug Combinations; D007377:Interleukin-3; D007797:Laminin; D040201:Platelet Membrane Glycoprotein IIb; D011509:Proteoglycans; D019718:Receptors, CXCR4; C059485:matrigel; D002392:Catechin; D003094:Collagen; D013926:Thrombopoietin; C045651:epigallocatechin gallate; D020780:Matrix Metalloproteinase 9; D053511:Matrix Metalloproteinase 14