中文摘要：

目的 观察miRNAs在人骨髓间充质干细胞（MSC）中的表达情况。方法以从骨髓中分离培养的人骨髓MSC为实验对象，分离提取细胞内小片段RNA（≤200nt），经多聚腺苷酸化和5旌接子连接后进行反转录，扩增克隆到得到大约109bp的DNA片段，测序后经生物信息学分析确定miRNAs的表达情况。选取部分miRNAs和新发现miRNAs，合成相应探针，与从人骨髓MSC、人成骨肉瘤细胞系SOSP-9607和大鼠成骨肉瘤细胞系UMR-106中分离出的小片段RNA进行杂交验证（Northern blot）。结果 成功从骨髓中分离培养出骨髓MSC，流式细胞仪检测93％以上的MSC表达CD44，但不表达CD34、CD45。从MSC中克隆测序得到194个克隆体，经生物信息学分析发现52个miRNAs（27种），其中包括26种已知的miRNAs和1种Nature杂志预测的miRNAs（PREDICTED-miR-202）。选取4条miRNAs（miR-495、miR-34a、miR-17-5p和PREDICTED-miR-202）进行Northem blot验证，发现它们均在MSC中表达。其中miR-34a和PREDICTED-miR-202只表达于MSC，miR-495在MSC和SOSP-9607中表达，miR-17—5p在3种细胞中均有表达。结论 筛选出了在人骨髓MSC中表达的miRNAs，为miRNAs参与调控MSC的自我更新提供了依据，同时为miRNAs在干细胞中的潜在应用奠定了基础。

英文摘要：

Objective To identify the expression of miRNAs in human bone marrow-derived mesenchymal stem cells （hMSCs）. Method Low molecular weight RNA fraction （≤200nt） from human bone marrow-derived mesenchymal stem cells was extracted, and polyadenylated by poly（A） polymerase, Then a 5rRNA adapter was ligated to poly（A）-tailed RNA using T4 RNA ligase, RNAs were reversely transcribed and amplified by RT-PCR. The PCR products with a size of about 109 bp were recovered and cloned into pCR 4-TOPO vector. After sequencing, database searching, and expression profiling, the expression of miRNAs in hMSCs was sieve＆ The expression of novel and some known miRNAs was examined by Northern blotting with small RNAs （≤200nt） isolated from hMSCs, osteosarcoma cell line SOSP-9607 and UMR-106. Results hMSCs were isolated from bone marrow and purified by centrifuge and in vitro culture. Cell markers CD44 were positive, but CD34 and CD45 were negative. A total of 194 clones were subsequently characterized by DNA sequencing and database searching. 52 clones （correspond to 27species） out of 194 clones from hMSCs were identified as miRNAs. One novel miRNAs （PREDICTED-miR-202） was discovered among other 26 known miRNAs, which were predicted in Nature Northern blotting confirmed that 1 novel miRNAs and 3 known miRNAs （miR-495, miR-34a, miR-17-5p, PREDICTED-miR-202） were stably expressed in hMS~. Conelmion These findings indicate that a large diverse population of miRNAs are likely important regulators for hMSCs in maintaining their state of self-renewal, and have potential value in stem cells research.