Berger Anthony J, Anvari Golnaz, Bellas Evangelia
Department of Bioengineering, College of Engineering, Temple University, 1947 N. 12th Street, Philadelphia, PA 19122 USA.
Department of Surgery, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19122 USA.
Cell Mol Bioeng. 2021 Oct 13;14(5):397-408. doi: 10.1007/s12195-021-00705-9. eCollection 2021 Oct.
Adipose derived stem cells (ASCs) hold great promise for clinical applications such as soft tissue regeneration and for tissue models and are notably easy to derive in large numbers. Specifically, ASCs provide an advantage for models of adipose tissue, where they can be employed as tissue specific cells and for patient specific models. However, ASC expansion may unintentionally reduce adipogenic capacity due to the stiffness of tissue culture plastic (TCPS).
Here, we expanded freshly isolated ASCs on soft and stiff substrates for 4 passages before adipogenic differentiation. At the last passage we swapped the substrate from stiff to soft, or soft to stiff to determine if short term exposure to a different substrate altered adipogenic capacity.
Expansion on stiff substrates reduced adipogenic capacity by 50% which was not rescued by swapping to a soft substrate for the last passage. Stiff substrates had greater nuclear area and gene expression of nesprin-2, a protein that mediates the tension of the nuclear envelope by tethering it to the actin cytoskeleton. Upon swapping to a soft substrate, the nuclear area was reduced but nesprin-2 levels did not fully recover, which differentially regulated cell commitment transcriptional factors.
Therefore, expansion on stiff substrates must be carefully considered when the end-goal of the expansion is for adipose tissue or soft tissue applications.
脂肪来源干细胞（ASC）在软组织再生等临床应用以及组织模型方面具有巨大潜力，并且特别易于大量获取。具体而言，ASC为脂肪组织模型提供了优势，在该模型中它们可作为组织特异性细胞以及患者特异性模型。然而，由于组织培养塑料（TCPS）的硬度，ASC的扩增可能会无意中降低其成脂能力。
在此，我们将新鲜分离的ASC在软质和硬质基质上扩增4代后进行成脂分化。在最后一代，我们将基质从硬质换成软质，或从软质换成硬质，以确定短期暴露于不同基质是否会改变成脂能力。
在硬质基质上扩增使成脂能力降低了50%，在最后一代换成软质基质并不能挽救这种情况。硬质基质具有更大的核面积以及核膜层蛋白-2（nesprin-2）的基因表达，nesprin-2是一种通过将核膜与肌动蛋白细胞骨架相连来介导核膜张力的蛋白质。换成软质基质后，核面积减小，但nesprin-2水平并未完全恢复，这对细胞定向转录因子产生了不同的调节作用。
因此，当扩增的最终目标是用于脂肪组织或软组织应用时，必须谨慎考虑在硬质基质上的扩增。
