Jori F P, Melone M A B, Napolitano M A, Cipollaro M, Cascino A, Giordano A, Galderisi U
Department of Neurological Sciences, Second University of Naples, Naples, Italy.
Cell Death Differ. 2005 Jan;12(1):65-77. doi: 10.1038/sj.cdd.4401499.
Marrow stromal stem cells (MSCs) are stem-like cells that are currently being tested for their potential use in cell therapy for a number of human diseases. MSCs can differentiate into both mesenchymal and nonmesenchymal lineages. In fact, in addition to bone, cartilage and fat, it has been demonstrated that MSCs are capable of differentiating into neurons and astrocytes. RB and RB2/p130 genes are involved in the differentiation of several systems. For this reason, we evaluated the role of RB and RB2/p130 in the differentiation and apoptosis of MSCs under experimental conditions that allow for MSC differentiation toward the neuron-like phenotype. To this end, we ectopically expressed either RB or RB2/p130 and monitored proliferation, differentiation and apoptosis in rat primary MSC cultures induced to differentiate toward the neuron-like phenotype. Both RB and RB2/P130 decreased cell proliferation rate. In pRb-overexpressing cells, the arrest of cell growth was also observed in the presence of the HDAC-inhibitor TSA, suggesting that its antiproliferative activity does not rely upon the HDAC pathway, while the addition of TSA to pRb2/p130-overexpressing cells relieved growth inhibition. TUNEL reactions and studies on the expression of genes belonging to the Bcl-2 family showed that while RB protected differentiating MSCs from apoptosis, RB2/p130 induced an increase of apoptosis compared to controls. The effects of both RB and RB2/p130 on programmed cell death appeared to be HDAC- independent. Molecular analysis of neural differentiation markers and immunocytochemistry revealed that RB2/p130 contributes mainly to the induction of generic neural properties and RB triggers cholinergic differentiation. Moreover, the differentiation potentials of RB2/p130 and RB appear to rely, at least in part, on the activity of HDACs.
骨髓基质干细胞（MSCs）是一类干细胞样细胞，目前正在接受测试，以评估其在多种人类疾病细胞治疗中的潜在用途。MSCs能够分化为间充质和非间充质谱系。事实上，除了骨、软骨和脂肪外，已有研究表明MSCs能够分化为神经元和星形胶质细胞。RB和RB2/p130基因参与多个系统的分化过程。因此，我们在能够使MSCs向神经元样表型分化的实验条件下，评估了RB和RB2/p130在MSCs分化和凋亡中的作用。为此，我们异位表达RB或RB2/p130，并监测诱导分化为神经元样表型的大鼠原代MSCs培养物中的增殖、分化和凋亡情况。RB和RB2/P130均降低了细胞增殖速率。在过表达pRb的细胞中，即使存在HDAC抑制剂TSA，也观察到细胞生长停滞，这表明其抗增殖活性不依赖于HDAC途径，而向过表达pRb2/p130的细胞中添加TSA可缓解生长抑制。TUNEL反应以及对Bcl-2家族相关基因表达的研究表明，RB可保护分化中的MSCs免于凋亡，而与对照组相比，RB2/p130可诱导凋亡增加。RB和RB2/p130对程序性细胞死亡的影响似乎均不依赖于HDAC。对神经分化标志物的分子分析和免疫细胞化学显示，RB2/p130主要促进一般神经特性的诱导，而RB则触发胆碱能分化。此外，RB2/p130和RB的分化潜能似乎至少部分依赖于HDAC的活性。
