他克莫司对HaCaT细胞干细胞因子mRNA及小鼠B16黑素瘤细胞c-kit mRNA表达的影响

目的 探讨他克莫司对角质形成细胞干细胞因子(SCF)mRNA及黑素细胞c-kit mRNA表达水平的影响.方法 分别培养人永生化角质形成细胞(HaCaT)和小鼠B16黑素瘤细胞,经他克莫司作用48 h后,采用实时荧光定量PCR法检测SCF mRNA及c-kit mRNA的表达.结果 他克莫司作用后,HaCaT细胞SCF mRNA、B16黑素瘤细胞c-kit mRNA的相对表达量均升高,与空白对照组比较,差异均有统计学意义(P均<0.05).结论 他克莫司可以上调HaCaT细胞SCF mRNA及B16黑素瘤细胞c-kit mRNA的表达量.

Background:Hematopoietic stem cell (HSC) transplantation can be used to treat blood and immune system disorders. Fresh umbilical cord blood (UCB), a major source of HSC for potential clinical applications, contains a limited number of HSCs. Stem cell factor (SCF) activates HSC self-renewal and is being used to stimulate ex vivo expansion of HSCs for treating various hematologic diseases in clinic. Yet, the mechanism by which SCF stimulates and supports HSCs expansion remains poorly understood. Thus, the purpose of the study is to obtain novel monoclonal antibodies for structural and functional SCF characterizations, as well as for the optimization of HSCs ex vivo expansion. Methods:Recombinant human stem cell factor (rhSCF) was used for producing monoclonal antibody (mAb). High-titer mAb speciifc to rhSCF was selected by following immunochemical screening to various mAb cell lines. HSCs with CD34+ epitope were isolated from UCB using affinity chromatography. SCF activity was tested in an ex vivo HSC expansion assay, with use of flow cytometry for detection of CD34+ cell and total mononuclear cells. Part of rhSCF that contained the antibody-binding site was identified via immunoblot analysis of rhSCF tryptic peptides, rhSCF-speciifc mAb, and subsequent NH2-terminal amino acid sequence analysis of the detected peptides. Results: The mAb cell line 23C8 with a high titer was found to be speciifc for rhSCF. In ex vivo cord blood expansion assays, the ability of rhSCF to stimulate the expansion of CD34+ cells was significantly inhibited by 23C8 in a dose-dependet fashion(?). Through peptide mapping, the binding site of 23C8 on rhSCF was mapped to the ifrst 104 amino acids.. Conclusion: The mAb cell line 23C8 produces speciifc and inhibitory anti-rhSCF mAb. The mAb appears to bind directly to a part of rhSCF that is critical for biological activity. This functionally active site of rhSCF is located in the ifrst 104 amino acids from the NH2-terminus. The novel anti-rhSCF mAb will be valuable for further dissection of SCF functional domains and optimization of HSCs ex vivo expansion.