Isolation and characterization of a human cementocyte-like cell line, HCY-23

Abstract Cementum is the mineralized tissue covering the tooth root that functions in tooth attachment and post-eruptive adjustment of tooth position. It has been reported to be highly similar to bone in several respects but remains poorly understood in terms of development and regeneration. Here, we investigate whether cementocytes, the residing cells in cellular cementum, have the potential to be protagonist in cementum homeostasis, responding to endocrine signals and directing local cementum metabolism. Cells from healthy erupted human teeth were isolated using sequential collagenase/EDTA digestions, and maintained in standard cell culture conditions. A cementocyte-like cell line was cloned (HCY-23, for human cementocyte clone 23), which presented a cementocyte compatible gene expression signature, including the expression of dentin matrix protein 1 ( DMP1 ), sclerostin ( SOST ), and E11/gp38/podoplanin ( E11 ). In contrast, these cells did not express the odontoblast/dentin marker dentin sialoprotein ( DSPP ). HCY-23 cells produced mineral-like nodules in vitro under differentiation conditions, and were highly responsive to inorganic phosphate (Pi). Within the limits of the present study, it can be concluded that cementocytes are phosphate-responsive cells, and have the potential do play a key role in periodontal homeostasis and regeneration.摘要 牙骨质（cementum）是覆盖牙根的矿化组织，兼具牙齿附着与牙齿萌出后位置调整的功能。已有研究表明其在多个方面与骨组织高度相似，但人们对其发育与再生机制仍知之甚少。本研究旨在探究细胞性牙骨质中的常驻细胞——牙骨质细胞（cementocytes）是否可作为牙骨质稳态的核心调控者，响应内分泌信号并调控局部牙骨质代谢。研究人员通过分步胶原酶/乙二胺四乙酸（EDTA）消化法，从健康的已萌出人类牙齿中分离得到细胞，并在标准细胞培养条件下进行培养。最终成功克隆得到一株牙骨质细胞样细胞系（命名为HCY-23，即人牙骨质细胞克隆23），该细胞系呈现出符合牙骨质细胞特征的基因表达谱，包括牙本质基质蛋白1 (dentin matrix protein 1, DMP1)、骨硬化蛋白 (sclerostin, SOST) 以及E11/gp38/足突蛋白 (podoplanin, E11) 的表达。与之相反，该细胞不表达成牙本质细胞/牙本质标记物牙本质涎蛋白 (dentin sialoprotein, DSPP)。HCY-23细胞在体外分化培养条件下可形成类矿化结节，且对无机磷酸盐 (Pi) 具有高度响应性。基于本研究的限定范围，可得出如下结论：牙骨质细胞是一类响应磷酸盐的细胞，且有望在牙周稳态与再生过程中发挥关键作用。