Department of Adult Stem Cells, Institute of Reproduction and Stem Cell Engineering, Central South University, Changsha, China.
Exp Hematol. 2012 Oct;40(10):828-36. doi: 10.1016/j.exphem.2012.06.002. Epub 2012 Jun 9.
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.
富含半胱氨酸的酸性分泌蛋白(SPARC)是一种公认的调节因子,可影响细胞增殖、分化和存活。在这里,我们研究了 SPARC 对红细胞生成的影响。通过流式细胞术和集落形成测定分析 SPARC(-/-)小鼠骨髓中的红细胞生成。通过骨髓移植实验研究影响红细胞生成的机制。通过 MiniMACS 分离脐血 CD34(+)细胞,通过集落形成测定和红系分化培养评估 SPARC 对人红细胞生成的影响。SPARC(-/-)小鼠外周血(PB)中的血红蛋白水平较低。PB 中的红细胞计数或 BM 中 Ter119(+)红细胞的百分比在 SPARC(-/-)和 WT 小鼠之间没有明显差异。然而,SPARC(-/-)骨髓细胞(BMC)形成红系爆式集落形成单位(BFU-E)以及脾集落形成单位(CFU-S8)的能力显著降低。外源性 SPARC 的添加可以促进 SPARC(-/-)BMC 体外形成 BFU-E。并且 SPARC(-/-)BMC 形成 BFU-E 的受损能力可以通过移植到 WT BM 微环境中得到恢复,而 WT BMC 的 BFU-E 形成在移植到 SPARC(-/-)受体后受到损害。此外,外源性 SPARC 促进脐血 CD34(+)细胞形成红系集落和红系的血红蛋白化,但不影响糖蛋白 A 和 CD71 的表达水平。总之,我们的结果表明 SPARC 促进了红细胞祖细胞的发育,但不影响终末红细胞的分化。