Department of Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA.
Stem Cells. 2013 Jun;31(6):1097-106. doi: 10.1002/stem.1360.
While a variety of natural and synthetic matrices have been used to influence embryonic stem cell (ESC) self-renewal or differentiation, and ESCs also deposit a rich matrix of their own, the mechanisms behind how extracellular matrix affects cell fate are largely unexplored. The ESC matrix is continuously remodeled by matrix metalloproteinases (MMPs), a process that we find is enhanced by the presence of mouse embryonic fibroblast feeders in a paracrine manner. Matrix remodeling by MMPs aids in the self-renewal of ESCs, as inhibition of MMPs inhibits the ability of ESCs to self-renew. We also find that addition of the interstitial collagenase MMP1 is sufficient to maintain long-term leukemia inhibitory factor (LIF)-independent mouse ESC (mESC) self-renewal in a dose-dependent manner. This remarkable ability is due to the presence of endogenously produced self-renewal-inducing signals, including the LIF-family ligand ciliary neurotrophic factor, that are normally trapped within the ECM and become exposed upon MMP-induced matrix remodeling to signal through JAK and Stat3. These results uncover a new role for feeder cells in maintaining self-renewal and show that mESCs normally produce sufficient levels of autocrine-acting pro-self-renewal ligands.
虽然已经有多种天然和合成基质被用于影响胚胎干细胞(ESC)的自我更新或分化,而且 ESC 自身也会分泌丰富的基质,但细胞外基质如何影响细胞命运的机制在很大程度上仍未被探索。基质金属蛋白酶(MMPs)会不断重塑 ESC 基质,我们发现这种重塑过程会受到小鼠胚胎成纤维细胞饲养层以旁分泌方式存在的增强。MMPs 介导的基质重塑有助于 ESC 的自我更新,因为 MMPs 的抑制会抑制 ESC 自我更新的能力。我们还发现,间质胶原酶 MMP1 的添加足以以剂量依赖的方式维持长期白血病抑制因子(LIF)独立的小鼠 ESC(mESC)的自我更新。这种显著的能力归因于内源性产生的自我更新诱导信号的存在,包括 LIF 家族配体睫状神经营养因子,这些信号通常被困在细胞外基质中,并且在 MMP 诱导的基质重塑后暴露出来,通过 JAK 和 Stat3 信号传递。这些结果揭示了饲养细胞在维持自我更新中的新作用,并表明 mESC 通常会产生足够水平的自分泌作用的促自我更新配体。