Kashiwakura Yuji, Katoh Youichi, Tamayose Kenji, Konishi Hakuoh, Takaya Norihide, Yuhara Senji, Yamada Masanori, Sugimoto Koichi, Daida Hiroyuki
Department of Cardiology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo 113-8421, Japan.
Circulation. 2003 Apr 29;107(16):2078-81. doi: 10.1161/01.CIR.0000070082.64414.B5. Epub 2003 Apr 21.
Bone marrow stromal cells (BMSCs) have many characteristics of mesenchymal stem cells that can differentiate into smooth muscle cells (SMCs). However, there have been few studies closely following the cell development of smooth muscle lineage among BMSCs.
To investigate the possible existence of a cell population committed to the SMC lineage among bone marrow adhesion cells, we tried to detect and follow the in vitro differentiation of such a cell type by using a promoter-sorting method with a human SM22alpha promoter (-480 bp)/green fluorescent protein (GFP) construct. The construct was transfected to adhesion cells that appeared 5 days after the seeding of mononuclear cells from bone marrow. GFP was first detectable 5 days after the transfection in a cell population [Ad(G) cells], which expressed PDGF-beta but neither mature (calponin) nor immature (SMemb) SMC-specific proteins at that time. However, the cells were eventually grown into individual clones that expressed SMC-specific proteins (alpha-smooth muscle actin, calponin, and SM-1), suggesting that Ad(G) cells have partly at least progenitor properties. Because early studies have reported that PDGF-beta signaling plays pivotal roles in the differentiation of mesenchymal smooth muscle progenitor cells, Ad(G) cells might be putative mesenchymal smooth muscle progenitors expressing PDGF-beta.
We demonstrated the presence of a cell population fated to become SMCs and followed their differentiation into SMCs among BMSCs.
骨髓基质细胞（BMSCs）具有许多间充质干细胞的特征，能够分化为平滑肌细胞（SMCs）。然而，很少有研究密切追踪BMSCs中平滑肌谱系的细胞发育情况。
为了研究骨髓黏附细胞中可能存在的定向分化为SMC谱系的细胞群体，我们尝试通过使用人SM22α启动子（-480 bp）/绿色荧光蛋白（GFP）构建体的启动子分选方法来检测和追踪此类细胞类型的体外分化。将该构建体转染至骨髓单个核细胞接种5天后出现的黏附细胞。转染5天后，在一个细胞群体[Ad(G)细胞]中首次检测到GFP，此时该细胞群体表达血小板衍生生长因子β（PDGF-β），但不表达成熟（钙调蛋白）或未成熟（平滑肌胚蛋白）SMC特异性蛋白。然而，这些细胞最终生长为表达SMC特异性蛋白（α-平滑肌肌动蛋白、钙调蛋白和SM-1）的单个克隆，这表明Ad(G)细胞至少部分具有祖细胞特性。因为早期研究报道PDGF-β信号在间充质平滑肌祖细胞的分化中起关键作用，Ad(G)细胞可能是表达PDGF-β的假定间充质平滑肌祖细胞。
我们证明了在BMSCs中存在注定要成为SMCs的细胞群体，并追踪了它们向SMCs的分化过程。
