Seeger Tanja, Hart Melanie, Patarroyo Manuel, Rolauffs Bernd, Aicher Wilhelm K, Klein Gerd
University Medical Clinic Department II, Center for Medical Research, University of Tübingen, Tübingen, Germany.
Department of Urology, University of Tübingen, Tübingen, Germany.
PLoS One. 2015 Sep 25;10(9):e0137419. doi: 10.1371/journal.pone.0137419. eCollection 2015.
Multipotent mesenchymal stromal cells (MSCs) are well known for their tri-lineage potential and ability to differentiate in vitro into osteogenic, chondrogenic or adipogenic lineages. By selecting appropriate conditions MSCs can also be differentiated in vitro into the myogenic lineage and are therefore a promising option for cell-based regeneration of muscle tissue such as an aged or damaged sphincter muscle. For the differentiation into the myogenic lineage there is still a need to evaluate the effects of extracellular matrix proteins such as laminins (LM) which are crucial for different stem cell types and for normal muscle function. The laminin family consists of 16 functionally different isoforms with LM-211 being the most abundant isoform of adult muscle tissues. In the sphincter tissue a strong expression of the isoforms LM-211/221, LM-411/421 and LM-511/521 can be detected in the different cell layers. Bone marrow-derived MSCs in culture, however, mainly express the isoforms LM-411 and LM-511, but not LM-211. Even after myogenic differentiation, LM-211 can hardly be detected. All laminin isoforms tested (LM-211, LM-411, LM-511 and LM-521) showed a significant inhibition of the proliferation of undifferentiated MSCs but, with the exception of LM-521, they had no influence on the proliferation of MSCs cultivated in myogenic medium. The strongest cellular adhesion of MSCs was to LM-511 and LM-521, whereas LM-211 was only a weakly-adhesive substrate for MSCs. Myogenic differentiation of MSCs even reduced the interaction with LM-211, but it did not affect the interaction with LM-511 and LM-521. Since during normal myogenesis the latter two isoforms are the major laminins surrounding developing myogenic progenitors, α5 chain-containing laminins are recommended for further improvements of myogenic differentiation protocols of MSCs into smooth muscle cells.
多能间充质基质细胞（MSCs）以其三系分化潜能以及在体外分化为成骨、软骨或脂肪谱系的能力而闻名。通过选择合适的条件，MSCs也能在体外分化为肌源性谱系，因此是基于细胞的肌肉组织再生（如衰老或受损的括约肌肌肉）的一个有前景的选择。对于分化为肌源性谱系，仍需要评估细胞外基质蛋白（如层粘连蛋白（LM））的作用，这些蛋白对不同干细胞类型和正常肌肉功能至关重要。层粘连蛋白家族由16种功能不同的异构体组成，其中LM - 211是成人肌肉组织中最丰富的异构体。在括约肌组织中，可在不同细胞层检测到异构体LM - 211/221、LM - 411/421和LM - 511/521的强表达。然而，培养的骨髓来源的MSCs主要表达异构体LM - 411和LM - 511，而不表达LM - 211。即使在肌源性分化后，也很难检测到LM - 211。所有测试的层粘连蛋白异构体（LM - 211、LM - 411、LM - 511和LM - 521）均显示对未分化的MSCs增殖有显著抑制作用，但除LM - 521外，它们对在肌源性培养基中培养的MSCs增殖没有影响。MSCs与LM - 511和LM - 521的细胞黏附最强，而LM - 211只是MSCs的弱黏附底物。MSCs的肌源性分化甚至减少了与LM - 211的相互作用，但不影响与LM - 511和LM - 521的相互作用。由于在正常肌生成过程中，后两种异构体是围绕发育中的肌源性祖细胞的主要层粘连蛋白，因此建议使用含α5链的层粘连蛋白来进一步改进MSCs向平滑肌细胞的肌源性分化方案。
