小鼠胎肝和骨髓细胞基因表达差异的比较研究

Comparative Study of Differentially Expressed Genes in Mouse Bone Marrow and Fetal Liver Cells

造血发育经历了从卵黄囊到胎肝、胎脾并最终定位于骨髓的复杂过程。虽然已有部分研究发现决定这一迁移过程的重要因素是造血微环境 ,但缺乏对不同造血器官微环境差别的系统性比较研究。为了探讨胎肝与成年骨髓造血微环境差别的分子基础 ,对小鼠胎肝和骨髓细胞RNA进行cDNA微阵列 (cDNAmicroarray)杂交 ,以生物信息学方法分析杂交结果 ,并以RT PCR和Northernblot对杂交结果进行进一步验证。结果表明 ,在 588种具有重要功能的已知基因中 ,二者相比 ,骨髓高表达的基因有 65种 ,胎肝高表达的基因有 13 1种。进一步分析发现骨髓高表达的基因中与造血相关的基因有 3 9种 ,胎肝高表达的基因中与造血相关的有 71种 ,分别占差异基因群的60 %和 54%。RT PCR和Northernblot验证的结果表明 ,CD18、CD44及PSGL 1基因在骨髓中高表达而在胎肝中低表达或不表达 ,此结果与微阵列杂交结果相符。同时还发现 ,CD18和CD44基因在胎肝中的表达水平随胎龄增加呈下调趋势。结论 :胎肝与骨髓细胞的基因表达谱显著不同 ,其中某些基因的表达随发育阶段不同而变化。这些基因的差异性表达 ,尤其是与造血细胞发育、迁移、植入等密切相关基因的差别性表达 ,可能是胎肝造血兴衰。

Hematopoiesis undergoes several migrations fr om yolk sac to liver and spleen, and finally bone marrow until the en d of life. A number of investigations have demonstrated that the hematopoietic m icroenvironment plays very important role in this process. However, the exact m echanisms remain unknown. In order to systematically analyze and understand the role of hematopoietic microenvironment in the regulation and control of hemato poiesis, a microarray containing 588 complementary DNAs was used to compare the gene expressions between those in murine fetal liver and bone marrow cells. The results obtained from array hybridization were analyzed and reconfirmed by using bioinformatics and RT-PCR as well as Northern blot. The resul ts showed that 65 and 131 genes were relatively high expressed in bone marrow an d fetal liver cells respectively among 588 known genes in the array-membrane. A ccordin g to the survey in the PubMed, 39 out of bone-marrow-expressed genes and 71 in fetal-liver-expressed genes were closely related to the hematopoiesis. Furthe r reconfirmation by RT-PCR or Northern blot has demonstrated that CD18, CD44 an d PSGL-1 genes chosen for analysis were highly expressed in adult bone marrow, but unexpressed or lower expressed in fetal liver cells , resulting in high simi larity to the array results. Moreover, the expressi ons of CD18 and CD44 in fetal liver were down-regulated with the increment of gestational age. In conclusion, the gene expressions in bone marrow and fetal li ver cells are obviously different, some of the genes are down-regul ated at the different stages of ontogeny. The different gene expression levels b etween bone marrow and fetal liver, especially those genes closely related to th e hematopoiesis, may be the molecular basis for the explanation of why hematopo i etic stem cells derived from different tissues have different characterizations as well as the differences from the beginning and terminating of fetal liver he matopoie sis, and why hematopoietic stem cells derived from fetal liver is tremendously d ifficult to be grafted in bone marrow.