SPARC promotes the development of erythroid progenitors.
Secreted protein acidic and rich in cysteine (SPARC) is a well-recognized regulator that affects cell proliferation, differentiation, and survival. Here, we investigated the impact of SPARC on erythropoiesis. Erythropoiesis in bone marrow (BM) from SPARC(-/-) mice was analyzed by flow cytometry and colony-forming assays. The mechanisms that affected erythropoiesis were investigated by BM transplantation experiments. CD34(+) cells from umbilical cord blood were isolated by MiniMACS, and the effect of SPARC on human erythropoiesis was assessed by colony-formation assay and erythroid differentiation culture. The hemoglobin level in peripheral blood (PB) was lower in SPARC(-/-) mice. Neither red blood cell count in PB nor the percentage of Ter119(+) erythrocytes in BM showed significant difference between SPARC(-/-) and WT mice. However, the ability of SPARC(-/-) bone marrow cells (BMCs) to form erythroid burst-forming units (BFU-E), as well as spleen colony-forming units (CFU-S8), was significantly decreased. The addition of exogenous SPARC could promote the formation of BFU-E from SPARC(-/-) BMCs in vitro. And the impaired ability of SPARC(-/-) BMCs to form BFU-E could be restored by transplanted into WT BM microenvironment, whereas the BFU-E formation of WT BMCs was impaired after transplanted into SPARC(-/-) recipients. Furthermore, exogenous SPARC promoted umbilical cord blood CD34(+) cells to form erythroid colonies and the hemoglobinization of erythroid, but did not affect the expression levels of glycophorin A and CD71. In conclusion, our results indicate that SPARC promotes the development of erythroid progenitors, but does not affect terminal erythroid differentiation.
Department of Adult Stem Cells, Institute of Reproduction and Stem Cell Engineering, Central South University, Changsha, China.
Zhen
Z
Luo
Pan
P
Luo
Yan
Y
Yu
Qian
Q
Zhao
Xiuhua
X
Zhao
Lamei
L
Cheng
D000818:Animals; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D016026:Bone Marrow Transplantation; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D003114:Colony-Forming Units Assay / Q000379:methods; D015672:Erythroid Precursor Cells / Q000166:cytology / Q000378:metabolism*; D004920:Erythropoiesis / Q000502:physiology*; D005312:Fetal Blood / Q000166:cytology / Q000378:metabolism*; D006021:Glycophorins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D015676:Osteonectin / Q000235:genetics / Q000378:metabolism*; D011990:Receptors, Transferrin / Q000235:genetics / Q000378:metabolism
D015703:Antigens, CD; C068126:CD71 antigen; D006021:Glycophorins; D015676:Osteonectin; D011990:Receptors, Transferrin