Characterisation of Cultured Mesothelial Cells Derived from the Murine Adult Omentum

The human omentum has been long regarded as a healing patch, used by surgeons for its ability to immunomodulate, repair and vascularise injured tissues. A major component of the omentum are mesothelial cells, which display some of the characteristics of mesenchymal stem/stromal cells. For instance, lineage tracing studies have shown that mesothelial cells give rise to adipocytes and vascular smooth muscle cells, and human and rat mesothelial cells have been shown to differentiate into osteoblast- and adipocyte-like cells in vitro, indicating that they have considerable plasticity. However, so far, long-term cultures of mesothelial cells have not been successfully established due to early senescence. Here, we demonstrate that mesothelial cells isolated from the mouse omentum could be cultured for more than 30 passages. While epithelial markers were downregulated over passages in the mesothelial cells, their mesenchymal profile remained unchanged. Early passage mesothelial cells displayed clonogenicitiy, expressed several stem cell markers, and up to passage 5 and 13, respectively, could differentiate along the adipogenic and osteogenic lineages, demonstrating stem/progenitor characteristics and differentiation potential.长期以来，人类网膜（omentum）被视为一种医用修复贴片，外科医生常利用其免疫调节、修复损伤组织并促进损伤部位血管生成的能力。网膜的主要组成成分为间皮细胞（mesothelial cells），这类细胞具备间充质干细胞/基质细胞（mesenchymal stem/stromal cells）的部分特征。例如，谱系示踪（lineage tracing）研究证实，间皮细胞可分化为脂肪细胞与血管平滑肌细胞；人类及大鼠的间皮细胞在体外可被诱导分化为成骨细胞样及脂肪细胞样细胞，这表明其具有较强的细胞可塑性。然而截至目前，由于早期细胞衰老问题，间皮细胞的长期体外培养始终未能成功建立。本研究证实，从小鼠网膜中分离得到的间皮细胞可连续传代超过30次。随着传代次数增加，间皮细胞的上皮标志物（epithelial markers）表达逐渐下调，但其间充质表型却保持稳定。早期传代的间皮细胞具备克隆形成能力，可表达多种干细胞标志物；且分别在传代5代及13代前，仍可沿成脂及成骨分化谱系进行分化，这表明其具有干/祖细胞特性与分化潜能。