Award type：Award from Japanese society, conference, symposium, etc. 

Language：English   Publisher：Stem Cells and Development  

The periodontal ligament (PDL) is a fibrous connective tissue that connects the cementum of the root to the alveolar bone. PDL stem cells (PDLSCs) contained in the PDL can differentiate into cementoblasts, osteoblasts, and PDL fibroblasts, with essential roles in periodontal tissue regeneration. Therefore, PDLSCs are expected to be useful in periodontal tissue regeneration therapy. In a previous study, we differentiated induced pluripotent stem cells (iPSCs) into PDLSC-like cells (iPDLSCs), which expressed PDL-related markers and mesenchymal stem cell (MSC) markers; they also exhibited high proliferation and multipotency. However, the iPSCs used in this differentiation method were cultured on mouse embryonic fibroblasts; thus, they constituted on-feeder iPSCs (OF-iPSCs). Considering the risk of contamination with feeder cell-derived components, iPDLSCs differentiated from OF-iPSCs (ie, OF-iPDLSCs) are unsuitable for clinical applications. In this study, we aimed to obtain PDLSC-like cells from feeder-free iPSCs (FF-iPSCs) using OF-iPDLSC differentiation method. First, we differentiated FF-iPSCs into neural crest cell-like cells (FF-iNCCs) and confirmed that FF-iNCCs expressed NCC markers (eg, Nestin and p75NTR). Then, we cultured FF-iNCCs on human primary PDL cell-derived extracellular matrix for 2 weeks; the resulting cells were named FF-iPDLSCs. FF-iPDLSCs exhibited higher expression of PDL-related and MSC markers compared with OF-iPDLSCs. FF-iPDLSCs also demonstrated proliferation and multipotency in vitro. Finally, we analyzed the ability of FF-iPDLSCs to form periodontal tissue in vivo upon subcutaneous transplantation with β-tricalcium phosphate scaffolds into dorsal tissues of immunodeficient mice. Eight weeks after transplantation, FF-iPDLSCs had formed osteocalcin-positive bone/cementum-like tissues and collagen 1-positive PDL-like fibers. These results suggested that we successfully obtained PDLSC-like cells from FF-iPSCs. Our findings will contribute to the development of novel periodontal regeneration therapies.

DOI： 10.1089/scd.2024.0122

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PubMed

Language：English   Publisher：Stem Cells and Development  

Periodontal tissue regeneration is important for preserving teeth. Periodontal ligament stem cells (PDLSCs) are useful in periodontal tissue regeneration; however, tooth extraction is required to obtain these cells. Therefore, we focused on induced pluripotent stem (iPS) cells and established a method to obtain PDLSC-like cells from iPS cells. Specifically, we first differentiated iPS cells into neural crest-like cells (iNCs). Next, we obtained PDLSC-like cells (iPDLSCs) by culturing iNCs on extracellular matrix (ECM) derived from human primary periodontal ligament cells (HPDLCs). This differentiation method suggested that ECM derived from HPDLCs is important for iPDLSC differentiation. Thus, we aimed to identify the PDLSC-inducing factor present in HPDLC-derived ECM in this study. We first performed comprehensive analyses of HPDLC genes and identified fibrillin-2 (FBN2), an ECM-related factor. Furthermore, to clarify the effect of FBN2 on iPDLSC differentiation, we cultured iNCs using ECM derived from HPDLCs with FBN2 knocked down. As a result, expression of PDL-related markers was reduced in iNCs cultured on ECM derived from HPDLCs transfected with FBN2 siRNA (iNC-siFBN2) compared with iPDLSCs. Furthermore, the expression of CD105 (a mesenchymal stem cell marker), proliferation ability, and multipotency of iNC-siFBN2 were lower compared with iPDLSCs. Next, we cultured iNCs on FBN2 recombinant protein; however, expression of PDL-related markers did not increase compared with iPDLSC. The present results suggest the critical involvement of FBN2 in inducing iPDLSCs from iNCs when in fact it does not promote iPDLSC differantiation. Therefore, we need to elucidate the entire HPDLC-ECMs, responsible for iPDLSCs induction.

DOI： 10.1089/scd.2024.0013

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Language：Japanese   Publisher：(一社)日本歯内療法学会  

ニッケルチタン(NiTi)製ファイルは根管治療を行う上で重要な器具のひとつである。NiTi合金は熱処理によって圧縮強さや引っ張り強さが変化することが知られており、プログライダーは熱処理加工されていないNiTiファイルと比較して柔軟性と破折抵抗性に優れる。本研究では、プログライダーとOptimum Glide Path(OGP)モードならびに新駆動方式(N-OGPモード)を組み合わせ、穿通の可否および穿通までに要した時間を検証することで、レシプロケーション運動による熱処理NiTiファイルの使用が根尖孔穿通のオプションのひとつとなる可能性について検討した。根管の先端径が0.1mmであるS字根管模型70本を実験に使用し、術者は当科に所属する臨床経験年数6～11年の歯科医師7名(Practician Group)と経験1年未満の研修歯科医7名(Trainee Group)とした。Practician Groupではすべての術者において5群とも穿通が可能であり、穿通率は100%であった。穿通までに要した時間は短い順にN-OGP+SPF、OGP+SPF、OGP+PRG、N-OGP+PRG、KFであった。Trainee Groupでは1術者のOGP+PRGにおいてのみファイル破折が生じたため穿通不可であったが、他の術者および実験群では穿通が可能であり、穿通率は97.1%であった。穿通までに要した時間は短い順にOGP+SPF、N-OGP+PRG、N-OGP+SPF、OGP+PRG、KFであった。

Language：English   Publisher：Scientific Reports  

Conventional direct pulp-capping materials induce pulp cells to secrete various biomolecules in pulp tissues that promote reparative dentin formation through induction of odontoblastic differentiation of dental pulp stem cells (DPSCs). However, these biomolecules sometimes induce bone-like dentin with poor sealing properties. Therefore, exploration of biomolecules that allow tight sealing by tubular reparative dentin is required. We recently reported that dopamine (DA) is involved in dentinogenesis. Hence, we investigated the effect of DA on odontoblastic differentiation of DPSCs and reparative dentin formation. Both tyrosine hydroxylase (TH), a DA synthetase, and DA were expressed in odontoblast-like cells in vivo. In vitro, their expression was increased during odontoblastic differentiation of DPSCs. Furthermore, TH-overexpressing DPSCs had promoted odontoblastic differentiation and DA production. Moreover, DA stimulation promoted their differentiation and induced tubular reparative dentin. These results suggest that DA produced by TH is involved in odontoblastic differentiation of DPSCs and has an inductive capacity for reparative dentin formation similar to primary dentin. This study may lead to the development of therapy to preserve vital pulp tissues.

DOI： 10.1038/s41598-023-32126-1

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Language：English  

DOI： 10.3390/biomedicines10123269

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PubMed

Event date： 2023.3

Event date： 2022.3

Event date： 2022.3

Language：Japanese