The epithelial cell rests of Malassez (ERM) are odontogenic epithelial cells located within the periodontal ligament matrix. While their function is unknown, they may support tissue homeostasis and maintain periodontal ligament space or even contribute to periodontal regeneration. We investigated the notion that ERM contain a subpopulation of stem cells that could undergo epithelial–mesenchymal transition and differentiate into mesenchymal stem-like cells with multilineage potential. For this purpose, ERM collected from ovine incisors were subjected to different inductive conditions in vitro, previously developed for the characterization of bone marrow mesenchymal stromal/stem cells (BMSC). We found that ex vivo-expanded ERM expressed both epithelial (cytokeratin-8, E-cadherin, and epithelial membrane protein-1) and BMSC markers (CD44, CD29, and heat shock protein-90β). Integrin α6/CD49f could be used for the enrichment of clonogenic cell clusters [colony-forming units-epithelial cells (CFU-Epi)]. Integrin α6/CD49f-positive-selected epithelial cells demonstrated over 50- and 7-fold greater CFU-Epi than integrin α6/CD49f-negative cells and unfractionated cells, respectively. Importantly, ERM demonstrated stem cell-like properties in their differentiation capacity to form bone, fat, cartilage, and neural cells in vitro. When transplanted into immunocompromised mice, ERM generated bone, cementum-like and Sharpey's fiber-like structures. Additionally, gene expression studies showed that osteogenic induction of ERM triggered an epithelial–mesenchymal transition. In conclusion, ERM are unusual cells that display the morphological and phenotypic characteristics of ectoderm-derived epithelial cells; however, they also have the capacity to differentiate into a mesenchymal phenotype and thus represent a unique stem cell population within the periodontal ligament.
Get full access to this article
View all access options for this article.
References
1.
BeertsenW, McCullochCA, SodekJ. 1997. The periodontal ligament: a unique, multifunctional connective tissue. Periodontol 2000, 13:20–40.
2.
DiekwischTG. 2001. The developmental biology of cementum. Int J Dev Biol, 45:695–706.
3.
Ten CateAR. 1996. The role of epithelium in the development, structure and function of the tissues of tooth support. Oral Dis, 2:55–62.
RinconJC, YoungWG, BartoldPM. 2006. The epithelial cell rests of Malassez—a role in periodontal regeneration?J Periodontal Res, 41:245–252.
6.
OhshimaM, YamaguchiY, MickeP, AbikoY, OtsukaK. 2008. In vitro characterization of the cytokine profile of the epithelial cell rests of Malassez. J Periodontol, 79:912–919.
7.
LindskogS, BlomlofL, HammarstromL. 1988. Evidence for a role of odontogenic epithelium in maintaining the periodontal space. J Clin Periodontol, 15:371–373.
8.
HasegawaN, KawaguchiH, OgawaT, UchidaT, KuriharaH. 2003. Immunohistochemical characteristics of epithelial cell rests of Malassez during cementum repair. J Periodontal Res, 38:51–56.
9.
ShinmuraY, TsuchiyaS, HataK, HondaMJ. 2008. Quiescent epithelial cell rests of Malassez can differentiate into ameloblast-like cells. J Cell Physiol, 217:728–738.
10.
BacigalupoA, FrassoniF, Van LintMT. 2000. Bone marrow or peripheral blood as a source of stem cells for allogeneic transplants. Curr Opin Hematol, 7:343–347.
11.
BucknerCD. 1999. Autologous bone marrow transplants to hematopoietic stem cell support with peripheral blood stem cells: a historical perspective. J Hematother, 8:233–236.
12.
HuangGT, GronthosS, ShiS. 2009. Mesenchymal stem cells derived from dental tissues vs. those from other sources: their biology and role in regenerative medicine. J Dent Res, 88:792–806.
13.
GronthosS, MankaniM, BrahimJ, RobeyPG, ShiS. 2000. Postnatal human dental pulp stem cells (DPSCs) in vitro and in vivo. Proc Natl Acad Sci U S A, 97:13625–13630.
14.
MiuraM, GronthosS, ZhaoM, LuB, FisherLW, RobeyPG, ShiS. 2003. SHED: stem cells from human exfoliated deciduous teeth. Proc Natl Acad Sci U S A, 100:5807–5812.
15.
SeoBM, MiuraM, GronthosS, BartoldPM, BatouliS, BrahimJ, YoungM, RobeyPG, WangCY, ShiS. 2004. Investigation of multipotent postnatal stem cells from human periodontal ligament. Lancet, 364:149–155.
SonoyamaW, LiuY, YamazaT, TuanRS, WangS, ShiS, HuangGT. 2008. Characterization of the apical papilla and its residing stem cells from human immature permanent teeth: a pilot study. J Endod, 34:166–171.
18.
MorsczeckC, GotzW, SchierholzJ, ZeilhoferF, KuhnU, MohlC, SippelC, HoffmannKH. 2005. Isolation of precursor cells (PCs) from human dental follicle of wisdom teeth. Matrix Biol, 24:155–165.
19.
ZhangQ, ShiS, LiuY, UyanneJ, ShiY, LeAD. 2009. Mesenchymal stem cells derived from human gingiva are capable of immunomodulatory functions and ameliorate inflammation-related tissue destruction in experimental colitis. J Immunol, 183:7787–7798.
20.
OwensRB, SmithHS, Nelson-ReesWA, SpringerEL. 1976. Epithelial cell cultures from normal and cancerous human tissues. J Natl Cancer Inst, 56:843–849.
21.
RinconJC, XiaoY, YoungWG, BartoldPM. 2005. Production of osteopontin by cultured porcine epithelial cell rests of Malassez. J Periodontal Res, 40:417–426.
22.
KuznetsovSA, KrebsbachPH, SatomuraK, KerrJ, RiminucciM, BenayahuD, RobeyPG. 1997. Single-colony derived strains of human marrow stromal fibroblasts form bone after transplantation in vivo. J Bone Miner Res, 12:1335–1347.
23.
MenicaninD, BartoldPM, ZannettinoAC, GronthosS. 2010. Identification of a common gene expression signature associated with immature clonal mesenchymal cell populations derived from bone marrow and dental tissues. Stem Cells Dev, 19:1501–1510.
24.
WadaN, MenicaninD, ShiS, BartoldPM, GronthosS. 2009. Immunomodulatory properties of human periodontal ligament stem cells. J Cell Physiol, 219:667–676.
25.
ShiS, GronthosS. 2003. Perivascular niche of postnatal mesenchymal stem cells in human bone marrow and dental pulp. J Bone Miner Res, 18:696–704.
26.
LiA, KaurP. 2005. FACS enrichment of human keratinocyte stem cells. Methods Mol Biol, 289:87–96.
27.
LiA, SimmonsPJ, KaurP. 1998. Identification and isolation of candidate human keratinocyte stem cells based on cell surface phenotype. Proc Natl Acad Sci U S A, 95:3902–3907.
28.
GronthosS, ZannettinoAC, HaySJ, ShiS, GravesSE, KortesidisA, SimmonsPJ. 2003. Molecular and cellular characterisation of highly purified stromal stem cells derived from human bone marrow. J Cell Sci, 116:1827–1835.
IsenmannS, ArthurA, ZannettinoAC, TurnerJL, ShiS, GlackinCA, GronthosS. 2009. TWIST family of basic helix-loop-helix transcription factors mediate human mesenchymal stem cell growth and commitment. Stem Cells, 27:2457–2468.
31.
ArthurA, RychkovG, ShiS, KoblarSA, GronthosS. 2008. Adult human dental pulp stem cells differentiate toward functionally active neurons under appropriate environmental cues. Stem Cells, 26:1787–1795.
32.
NamH, KimJ, ParkJ, ParkJC, KimJW, SeoBM, LeeJC, LeeG. 2011. Expression profile of the stem cell markers in human Hertwig's epithelial root sheath/Epithelial rests of Malassez cells. Mol Cells, 31:355–360.
33.
AziziSA, StokesD, AugelliBJ, DiGirolamoC, ProckopDJ. 1998. Engraftment and migration of human bone marrow stromal cells implanted in the brains of albino rats—similarities to astrocyte grafts. Proc Natl Acad Sci U S A, 95:3908–3913.
34.
FerrariG, Cusella-De AngelisG, ColettaM, PaolucciE, StornaiuoloA, CossuG, MavilioF. 1998. Muscle regeneration by bone marrow-derived myogenic progenitors. Science, 279:1528–1530.
KuciaM, RecaR, CampbellFR, Zuba-SurmaE, MajkaM, RatajczakJ, RatajczakMZ. 2006. A population of very small embryonic-like (VSEL) CXCR4(+)SSEA-1(+)Oct-4+ stem cells identified in adult bone marrow. Leukemia, 20:857–869.
37.
KrauseDS, TheiseND, CollectorMI, HenegariuO, HwangS, GardnerR, NeutzelS, SharkisSJ. 2001. Multi-organ, multi-lineage engraftment by a single bone marrow-derived stem cell. Cell, 105:369–377.
38.
LiR, LiangJ, NiS, ZhouT, QingX, LiH, HeW, ChenJ, LiFet al.2010. A mesenchymal-to-epithelial transition initiates and is required for the nuclear reprogramming of mouse fibroblasts. Cell Stem Cell, 7:51–63.
39.
Samavarchi-TehraniP, GolipourA, DavidL, SungHK, BeyerTA, DattiA, WoltjenK, NagyA, WranaJL. 2010. Functional genomics reveals a BMP-driven mesenchymal-to-epithelial transition in the initiation of somatic cell reprogramming. Cell Stem Cell, 7:64–77.
40.
YamanakaS, BlauHM. 2010. Nuclear reprogramming to a pluripotent state by three approaches. Nature, 465:704–712.
AasenT, RayaA, BarreroMJ, GarretaE, ConsiglioA, GonzalezF, VassenaR, BilicJ, PekarikVet al.2008. Efficient and rapid generation of induced pluripotent stem cells from human keratinocytes. Nat Biotechnol, 26:1276–1284.
43.
BrunetteDM, MelcherAH, MoeHK. 1976. Culture and origin of epithelium-like and fibroblast-like cells from porcine periodontal ligament explants and cell suspensions. Arch Oral Biol, 21:393–400.
44.
JiangXY, FuSL, NieBM, LiY, LinL, YinL, WangYX, LuPH, XuXM. 2006. Methods for isolating highly-enriched embryonic spinal cord neurons: a comparison between enzymatic and mechanical dissociations. J Neurosci Methods, 158:13–18.
45.
JonesPH, WattFM. 1993. Separation of human epidermal stem cells from transit amplifying cells on the basis of differences in integrin function and expression. Cell, 73:713–724.
46.
KaurP, LiA. 2000. Adhesive properties of human basal epidermal cells: an analysis of keratinocyte stem cells, transit amplifying cells, and postmitotic differentiating cells. J Invest Dermatol, 114:413–420.
CalenicB, IshkitievN, YaegakiK, ImaiT, KumazawaY, NasuM, HirataT. 2010. Magnetic separation and characterization of keratinocyte stem cells from human gingiva. J Periodontal Res, 45:703–708.
49.
IzumiK, TobitaT, FeinbergSE. 2007. Isolation of human oral keratinocyte progenitor/stem cells. J Dent Res, 86:341–346.
50.
GronthosS, McCartyR, MrozikK, FitterS, PatonS, MenicaninD, ItescuS, BartoldPM, XianC, ZannettinoAC. 2009. Heat shock protein-90 beta (Hsp90ss) is expressed at the surface of multipotential mesenchymal precursor cells (MPC): generation of a novel monoclonal antibody, STRO-4, with specificity for MPC from human and ovine tissues. Stem Cells Dev, 18:1253–1262.
51.
TechawattanawisalW, NakahamaK, KomakiM, AbeM, TakagiY, MoritaI. 2007. Isolation of multipotent stem cells from adult rat periodontal ligament by neurosphere-forming culture system. Biochem Biophys Res Commun, 357:917–923.
52.
SonoyamaW, SeoBM, YamazaT, ShiS. 2007. Human Hertwig's epithelial root sheath cells play crucial roles in cementum formation. J Dent Res, 86:594–599.
53.
TsaoMC, WalthallBJ, HamRG. 1982. Clonal growth of normal human epidermal keratinocytes in a defined medium. J Cell Physiol, 110:219–229.
54.
VaraniJ, ShayevitzJ, PerryD, MitraRS, NickoloffBJ, VoorheesJJ. 1990. Retinoic acid stimulation of human dermal fibroblast proliferation is dependent on suboptimal extracellular Ca2+ concentration. Am J Pathol, 136:1275–1281.
55.
StruysT, SchuermansJ, CorpasL, PolitisC, VrielinckL, SchepersS, JacobsR, IvoL. 2010. Proliferation of epithelial rests of Malassez following auto-transplantation of third molars: a case report. J Med Case Reports, 4:328.
56.
TalicNF, EvansCA, DanielJC, ZakiAE. 2003. Proliferation of epithelial rests of Malassez during experimental tooth movement. Am J Orthod Dentofacial Orthop, 123:527–533.
57.
HuangX, BringasPJr., SlavkinHC, ChaiY. 2009. Fate of HERS during tooth root development. Dev Biol, 334:22–30.
58.
JungHS, LeeDS, LeeJH, ParkSJ, LeeG, SeoBM, KoJS, ParkJC. 2011. Directing the differentiation of human dental follicle cells into cementoblasts and/or osteoblasts by a combination of HERS and pulp cells. J Mol Histol, 42:227–235.
59.
AkimotoT, FujiwaraN, KagiyaT, OtsuK, IshizekiK, HaradaH. 2010. Establishment of Hertwig's epithelial root sheath cell line from cells involved in epithelial-mesenchymal transition. Biochem Biophys Res Commun, 404:308–312.
RadiskyDC, LaBargeMA. 2008. Epithelial-mesenchymal transition and the stem cell phenotype. Cell Stem Cell, 2:511–512.
62.
PolyakK, WeinbergRA. 2009. Transitions between epithelial and mesenchymal states: acquisition of malignant and stem cell traits. Nat Rev Cancer, 9:265–273.
ManiSA, GuoW, LiaoMJ, EatonEN, AyyananA, ZhouAY, BrooksM, ReinhardF, ZhangCCet al.2008. The epithelial-mesenchymal transition generates cells with properties of stem cells. Cell, 133:704–715.
65.
ThieryJP, AcloqueH, HuangRY, NietoMA. 2009. Epithelial-mesenchymal transitions in development and disease. Cell, 139:871–890.
66.
LeeJM, DedharS, KalluriR, ThompsonEW. 2006. The epithelial-mesenchymal transition: new insights in signaling, development, and disease. J Cell Biol, 172:973–981.
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
