Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
Cell Biochem Funct. 2014 Jan;32(1):77-86. doi: 10.1002/cbf.2974. Epub 2013 May 8.
A close relationship between cell death and pathological calcification has recently been reported, such as vascular calcification in atherosclerosis. However, the roles of cell death in calcification by osteoblast lineage have not been elucidated in detail. In this study, we investigated whether cell death is involved in the calcification on osteoblastic differentiation of human bone marrow mesenchymal stem cells (hMSC) under osteogenic culture in vitro. Apoptosis and necrosis occurred in an osteogenic culture of hMSC, and cell death preceded calcification. The generation of intracellular reactive oxygen species, chromatin condensation and fragmentation, and caspase-3 activation increased in this culture. A pan-caspase inhibitor (Z-VAD-FMK) and anti-oxidants (Tiron and n-acetylcysteine) inhibited osteogenic culture-induced cell death and calcification. Furthermore, calcification was significantly promoted by the addition of necrotic dead cells or its membrane fraction. Spontaneously dead cells by osteogenic culture and exogenously added necrotic cells were surrounded by calcium deposits. Induction of localized cell death by photodynamic treatment in the osteogenic culture resulted in co-localized calcification. These findings show that necrotic and apoptotic cell deaths were induced in an osteogenic culture of hMSC and indicated that both necrotic and apoptotic cells of osteoblast lineage served as nuclei for calcification on osteoblastic differentiation of hMSC in vitro.
细胞死亡与病理性钙化之间存在密切关系，例如动脉粥样硬化中的血管钙化。然而，成骨细胞谱系中的细胞死亡在钙化过程中的作用尚未详细阐明。在这项研究中，我们研究了在体外成骨培养条件下，人骨髓间充质干细胞（hMSC）成骨分化过程中细胞死亡是否参与钙化。hMSC 的成骨培养中发生了细胞凋亡和坏死，并且细胞死亡先于钙化发生。该培养中细胞内活性氧的产生、染色质凝聚和片段化以及 caspase-3 的激活增加。泛半胱天冬酶抑制剂（Z-VAD-FMK）和抗氧化剂（Tiron 和 N-乙酰半胱氨酸）抑制成骨培养诱导的细胞死亡和钙化。此外，坏死的死细胞或其膜部分的添加显著促进了钙化。成骨培养中自发死亡的细胞和外源添加的坏死细胞被钙沉积物包围。在成骨培养中通过光动力处理诱导局部细胞死亡会导致钙沉积的共定位。这些发现表明在 hMSC 的成骨培养中诱导了坏死和凋亡性细胞死亡，并表明成骨细胞谱系中的坏死细胞和凋亡细胞都可以作为 hMSC 体外成骨分化过程中钙化的核心。
