Song Haibo, Wang Hui, Wu Weiwei, Qi Lei, Shao Lei, Wang Fang, Lai Yimu, Leach Desiree, Mathis Bryan, Janicki Joseph S, Wang Xing Li, Tang Dongqi, Cui Taixing
Shandong University Qilu Hospital Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital of Shandong University, Jinan, 250012, People's Republic of China.
Department of Cell Biology and Anatomy, University of South Carolina School of Medicine, Columbia, SC, 29208, USA.
Cell Tissue Res. 2015 Oct;362(1):97-113. doi: 10.1007/s00441-015-2193-9. Epub 2015 May 29.
Proliferative or synthetic vascular smooth muscle cells (VSMCs) are widely accepted to be mainly derived from the dedifferentiation or phenotypic modulation of mature contractile VSMCs, i.e., a phenotype switch from a normally quiescent and contractile type into a proliferative or synthetic form. However, this theory has been challenged by recent evidence that synthetic VSMCs predominantly originate instead from media-derived multipotent vascular stem cells (MVSCs). To test these hypotheses further, we re-examine whether the conventional rat aortic SMC (RASMC) culture involves the VSMC differentiation of MVSCs or the dedifferentiation of mature VSMCs and the potential mechanism for controlling the synthetic phenotype of RASMCs. We enzymatically isolated RASMCs and cultured the cells in both a regular growth medium (RGM) and a stem cell growth medium (SCGM). Regardless of culture conditions, only a small portion of freshly isolated RASMCs attaches, survives and grows slowly during the first 7 days of primary culture, while expressing both SMC- and MVSC-specific markers. RGM-cultured cells undergo a process of synthetic SMC differentiation, whereas SCGM-cultured cells can be differentiated into not only synthetic SMCs but also other somatic cells. Notably, compared with the RGM-cultured differentiated RASMCs, the SCGM-cultured undifferentiated cells exhibit the phenotype of MVSCs and generate greater amounts of reactive oxygen species (ROS) that act as a negative regulator of differentiation into synthetic VSMCs. Knockdown of phospholipase A2, group 7 (Pla2g7) suppresses ROS formation in the MVSCs while enhancing SMC differentiation of MVSCs. These results suggest that cultured synthetic VSMCs can be derived from the SMC differentiation of MVSCs with ROS as a negative regulator.
增殖性或合成性血管平滑肌细胞（VSMC）被广泛认为主要来源于成熟收缩性VSMC的去分化或表型调节，即从正常静止和收缩型的表型转变为增殖性或合成型。然而，这一理论受到了最近证据的挑战，该证据表明合成性VSMC主要来源于中膜来源的多能血管干细胞（MVSC）。为了进一步验证这些假设，我们重新审视了传统的大鼠主动脉平滑肌细胞（RASMC）培养是否涉及MVSC的VSMC分化或成熟VSMC的去分化，以及控制RASMC合成表型的潜在机制。我们通过酶法分离RASMC，并将细胞分别培养在常规生长培养基（RGM）和干细胞生长培养基（SCGM）中。无论培养条件如何，在原代培养的前7天，只有一小部分新鲜分离的RASMC附着、存活并缓慢生长，同时表达SMC和MVSC特异性标记物。RGM培养的细胞经历合成性SMC分化过程，而SCGM培养的细胞不仅可以分化为合成性SMC，还可以分化为其他体细胞。值得注意的是，与RGM培养的分化RASMC相比，SCGM培养的未分化细胞表现出MVSC的表型，并产生大量作为合成性VSMC分化负调节因子的活性氧（ROS）。敲低磷脂酶A2第7组（Pla2g7）可抑制MVSC中的ROS形成，同时增强MVSC的SMC分化。这些结果表明，培养的合成性VSMC可以来源于MVSC的SMC分化，其中ROS作为负调节因子。
