CD45-positive cells are not an essential component in cardiosphere formation.
The cardiosphere (CS) is composed of a heterogeneous population of cells, including CD45(+) cells that are bone marrow (BM)-derived. However, whether the CD45(+) cells are an essential cell component in CS formation is unknown. The current study was undertaken to address this question. Cardiospheres (CSs) were harvested from 1-week post-myocardial infarction (MI) or non-MI hearts of C57BL/6 J mice. The process of CS formation was observed by timelapse photography. To analyze the role of BM-derived CD45(+) cells in CS formation, CD45(+) cells were depleted from populations of CS-forming cells by immunomagnetic beads. We recorded the number of CSs formed in culture from the same amount (10(5)) of intact CS-forming cells, from CD45(+)-cell-depleted CS-forming cells and from CD45(+) cells alone (n=6-9/cell type). CS-forming cells selectively aggregated together to form CSs by 35 h after plating. The depletion of CD45(+) cells from CS-forming cells actually increased the formation of CSs (67±10 CSs/10(5) cells) compared with non-depleted CS-forming cells (51±6 CSs/10(5) cells, P<0.0001). Purified CD45(+) cells from CS-forming cells did not form CSs in culture. Thus, BM-derived CD45(+) cells including BM progenitors are neither necessary nor sufficient for CS formation.
Department of Medicine, Division of Cardiology, University of California, San Francisco, San Francisco, CA, USA.
Jianqin
J
Ye
Andrew J
AJ
Boyle
Henry
H
Shih
Richard E
RE
Sievers
Zhi-En
ZE
Wang
Matthew
M
Gormley
Yerem
Y
Yeghiazarians
D000818:Animals; D001854:Bone Marrow Cells / Q000166:cytology / Q000378:metabolism; D049109:Cell Proliferation; D017493:Leukocyte Common Antigens / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism; D018874:Spheroids, Cellular / Q000166:cytology* / Q000378:metabolism
D017493:Leukocyte Common Antigens