CD44在小鼠下颌第一磨牙牙冠发育过程中的表达及作用

doi:10.13591/j.cnki.kqyx.2026.05.002

摘要/Abstract

摘要：

目的探讨CD44在小鼠下颌第一磨牙牙冠发育过程中的时空表达特征及其生物学作用。方法采用胚胎期E11.5至出生后PN7不同发育阶段的小鼠下颌第一磨牙样本，通过免疫组织化学染色检测下颌第一磨牙CD44蛋白在其发育过程中的定位与表达，并采用实时定量PCR分析其mRNA表达水平。为进一步探究CD44的功能，分离E16.5小鼠下颌第一磨牙牙胚进行体外器官培养，并转染小干扰RNA（siRNA）以敲低CD44表达。通过大体形态观察、牙胚宽度与高度测量，并结合HE染色、Masson三色染色及免疫荧光染色技术，评估牙胚发育、成釉细胞与成牙本质细胞的分化状态、胶原分泌以及前期牙本质的形成情况。结果在牙胚发育起始阶段（E11.5），CD44在牙板上皮及深层牙源性间充质中均未见明显表达。在蕾状期（E13.5），CD44在牙上皮细胞中呈现微弱表达。从帽状期（E14.5）至钟状晚期（E18.5），CD44在成釉器各类细胞中均有表达，并于内釉上皮与中间层细胞中呈现高表达。出生后（PN1至PN7），CD44在成釉细胞与星网状层持续表达；自PN3起，在牙尖部的成牙本质细胞下层中也检测到阳性信号。RT-qPCR结果显示，CD44 mRNA的表达水平在PN5达到峰值。牙胚体外培养实验表明，与对照组相比，siCD44干扰组的牙胚宽度与高度均减小，成釉细胞与成牙本质细胞分化受阻，胶原纤维分泌减少，前期牙本质形成受损。结论 CD44在小鼠磨牙牙冠发育过程中呈现动态时空表达特征，抑制其表达可导致牙胚形态变化、关键细胞分化障碍及前期牙本质形成减少，提示CD44在该过程中发挥重要作用。

关键词: CD44, 牙冠发育, 成釉器, 免疫组织化学染色, 器官培养

Abstract:

Objective To investigate the spatiotemporal expression characteristics and biological functions of CD44 during the development of the mandibular first molar crown in mice. Methods Immunohistochemical staining was performed to examine CD44 protein localization and expression in the mandibular first molar tooth germs at different developmental stages from E11.5 （embryonic day 11.5） to PN7 （postnatal day 7）. Real-time quantitative PCR was used to analyze the mRNA expression level of CD44. To further explore the function of CD44，mouse mandibular first molar dental germs at E16.5 were isolated for organ culture and transfected with small interfering RNA to knock down CD44 expression. The overall morphology of the dental germs，their width and height，as well as the differentiation status of ameloblasts and odontoblasts，collagen secretion，and the formation of predentin were evaluated using HE staining，Masson trichrome staining，and immunofluorescence staining techniques. Results At the initiation stage of tooth germ development （E11.5），CD44 was not significantly expressed in the dental plate epithelium and the underlying mesenchyme. In the bud stage （E13.5），CD44 showed weak expression in the dental epithelial cells. From the cap stage （E14.5） to the late bell stage （E18.5），CD44 was expressed in all types of cells in the enamel organ，and was highly expressed in the inner enamel epithelium and stratum intermedium. After birth （PN1 to PN7），CD44 continued to be highly expressed in the ameloblasts and stratum reticulum. From PN3 onwards，positive signals were also detected in the sub-odontoblastic layer near the odontoblasts at the tooth cusps. RT-qPCR results showed that the expression level of CD44 mRNA reached its peak at PN5. The culture experiment of dental germs showed that compared with the control group，the width and height of the dental germ in the siCD44 group were reduced； the differentiation of ameloblasts and odontoblasts was inhibited； collagen secretion was significantly decreased，and the formation of predentin was impaired. Conclusion CD44 exhibits dynamic spatiotemporal expression characteristics during the development of the mandibular first molar crown in mice. Inhibiting its expression can affect the morphology of the dental germ，key cell differentiation，and the formation of predentin，suggesting that CD44 plays an important role in this process.

Key words: CD44, dental crown development, enamel organ, immunohistochemical staining, organ culture

中图分类号:

R339.35

司梦婷, 颜燕宏, 吴佳艳, 蒋备战. CD44在小鼠下颌第一磨牙牙冠发育过程中的表达及作用[J]. 口腔医学, 2026, 46(5): 330-336.

SI Mengting, YAN Yanhong, WU Jiayan, JIANG Beizhan. The spatiotemporal expression pattern of CD44 in developing mandibular first molar crown in mice[J]. Stomatology, 2026, 46(5): 330-336.

图/表 6

图1

图2

图3

图4

图5

图6

参考文献 21

[1]	Yu TS, Klein OD. Molecular and cellular mechanisms of tooth development, homeostasis and repair[J]. Development, 2020, 147(2): dev184754.
[2]	Krivanek J, Soldatov RA, Kastriti ME, et al. Dental cell type atlas reveals stem and differentiated cell types in mouse and human teeth[J]. Nat Commun, 2020, 11: 4816.
[3]	Hassn Mesrati M, Syafruddin SE, Mohtar MA, et al. CD44: A multifunctional mediator of cancer progression[J]. Biomolecules, 2021, 11(12): 1850.
[4]	Chen L, Fu CY, Zhang Q, et al. The role of CD44 in pathological angiogenesis[J]. FASEB J, 2020, 34(10): 13125-13139.
[5]	Felszeghy S, Módis L, Tammi M, et al. The distribution pattern of the hyaluronan receptor CD44 during human tooth development[J]. Arch Oral Biol, 2001, 46(10): 939-945.
[6]	Khadiza N, Hasegawa T, Nagai T, et al. Immunolocalization of podoplanin/E11/gp38, CD44, and endomucin in the odontoblastic cell layer of murine tooth germs[J]. Biomed Res, 2019, 40(4): 133-143.
[7]	Leonardi R, Loreto C, Caltabiano R, et al. Immunolocalization of CD44s in human teeth[J]. Acta Histochem, 2006, 108(6): 425-429.
[8]	Kajiura K, Umemura N, Ohkoshi E, et al. Shikonin induces odontoblastic differentiation of dental pulp stem cells AKT-mTOR signaling in the presence of CD44[J]. Connect Tissue Res, 2021, 62(6): 689-697.
[9]	Chen KL, Huang YY, Lung J, et al. CD44 is involved in mineralization of dental pulp cells[J]. J Endod, 2013, 39(3): 351-356.
[10]	Nakamura H, Ozawa H. Immunolocalization of CD44 and the ezrin-radixin-moesin(ERM)family in the stratum intermedium and papillary layer of the mouse enamel organ[J]. J Histochem Cytochem, 1997, 45(11): 1481-1492.
[11]	He B, Kram V, Furusawa T, et al. Epigenetic regulation of ameloblast differentiation by HMGN proteins[J]. J Dent Res, 2024, 103(1): 51-61.
[12]	Yuta T, Tian T, Chiba YT, et al. Development of a novel ex vivo organ culture system to improve preservation methods of regenerative tissues[J]. Sci Rep, 2023, 13: 3354.
[13]	Wang H, Wang X, Huang L, et al. Overburdened ferroptotic stress impairs tooth morphogenesis[J]. Elife, 2023, 12: 1-15.
[14]	Yamaguti PM, de la Dure-Molla M, Monnot S, et al. Unequal impact of COL1A1 and COL1A2 variants on dentinogenesis imperfecta[J]. J Dent Res, 2023, 102(6): 616-625.
[15]	Yang GF, Jiang BZ, Cai WP, et al. Hyaluronan and hyaluronan synthases expression and localization in embryonic mouse molars[J]. J Mol Histol, 2016, 47(4): 413-420.
[16]	Sánchez N, González-Ramírez MC, Contreras EG, et al. Balance between tooth size and tooth number is controlled by hyaluronan[J]. Front Physiol, 2020, 11: 996.
[17]	Weng X, Maxwell-Warburton S, Hasib A, et al. The membrane receptor CD44: Novel insights into metabolism[J]. Trends Endocrinol Metab, 2022, 33(5): 318-332.
[18]	Al-Rekabi Z, Fura AM, Juhlin I, et al. Hyaluronan-CD44 interactions mediate contractility and migration in periodontal ligament cells[J]. Cell Adhes Migr, 2019, 13(1): 139-151.
[19]	Hernández D, Miquel-Serra L, Docampo MJ, et al. Role of versican V0/V1 and CD44 in the regulation of human melanoma cell behavior[J]. Int J Mol Med, 2011, 27(2): 269-275.
[20]	Harada H, Takahashi M. CD44-dependent intracellular and extracellular catabolism of hyaluronic acid by hyaluronidase-1 and-2[J]. J Biol Chem, 2007, 282(8): 5597-5607.
[21]	Huang HY, Hu XY, Wu JY, et al. Hyaluronan degradation by HYAL2 is essential for odontoblastic differentiation and migration of mouse dental papilla cells[J]. Matrix Biol, 2024, 129: 1-14.