colonic vs bone marrow MSC

We found that mesenchymal stem cells isolated from colonic tissue express significantly increased expression of Ptgs2 or cox-2 compared to that of mesenchymal stem cells isolated from the bone marrow, one of the most common tissues from which this cell type is derived. We hypothesized that the localization of these cells in the colon exposes them to specific environmental factors that induce and/or maintain increased constitutive levels of cox-2 uniquely in this cell type. In order to identify possible candidate molecules regulating cox-2 in these cells, we decided to compare the transcriptomes of colonic mesenchymal stem cells and bone marrow-derived mesenchymal stem cells. Mesenchymal stem cells were isolated by fast plastic adherence after collagenase type I-mediated dissociation of the tissue of origin. Cells were maintained in culture in low glucose DMEM with 10mM HEPES and 10% FBS. Cells were passaged at 90-100% confluency. Approximately 4 million cells from four MSC lines, two from colon and two from bone marrow, were lysed between passages 5 and 10. Total RNA was isolated, amplified, and hybridized to Affymetrix MOE230.2 chips.

我们发现，从结肠组织分离得到的间充质干细胞（mesenchymal stem cells, MSCs），其Ptgs2（又称环氧化酶2，cox-2）的表达水平显著高于该细胞类型最常见的分离来源之一——骨髓来源的间充质干细胞。我们提出如下假说：这类细胞定位于结肠微环境中，使其暴露于特定的环境因子，这些因子可诱导并/或维持该类细胞中cox-2组成型表达水平的特异性升高。为了鉴定调控这类细胞中cox-2的潜在候选分子，我们计划对比结肠来源间充质干细胞与骨髓来源间充质干细胞的转录组。间充质干细胞的分离流程为：先用I型胶原酶（collagenase type I）介导来源组织解离，再通过快速塑料贴壁法完成分离。细胞培养于添加10mM羟乙基哌嗪乙磺酸（HEPES）与10%胎牛血清（Fetal Bovine Serum, FBS）的低糖DMEM（low glucose DMEM）中。细胞在汇合度达到90%-100%时进行传代。我们在第5至10代之间，对4株间充质干细胞系（2株来自结肠，2株来自骨髓）的约400万个细胞进行裂解。提取总RNA并进行扩增，随后与Affymetrix MOE230.2基因芯片进行杂交。