Enhancement of Differentiation and Mineralization of Human Dental Pulp Stem Cells via TGF-β Signaling in Low-Level Laser Therapy Using Er:YAG Lasers

Ryo Yoshida; Kazuyuki Kobayashi; Kazuo Onuma; Ryuji Yamamoto; Risako Chiba Ohkuma; Takeo Karakida; Shunjiro Yamakawa; Noriyasu Hosoya; Yasushi Yamazaki; Yasuo Yamakoshi

doi:10.1016/j.job.2025.100617

Enhancement of Differentiation and Mineralization of Human Dental Pulp Stem Cells via TGF-β Signaling in Low-Level Laser Therapy Using Er:YAG Lasers

J Oral Biosci. 2025 Jan 18:100617. doi: 10.1016/j.job.2025.100617. Online ahead of print.

Authors

Affiliations

¹ Department of Endodontology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan. Electronic address: [email protected].
² Department of Dental Hygiene, Tsurumi Junior College, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan. Electronic address: [email protected].
³ Department of Biochemistry and Molecular Biology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan. Electronic address: [email protected].
⁴ Department of Biochemistry and Molecular Biology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan. Electronic address: [email protected].
⁵ Department of Biochemistry and Molecular Biology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan. Electronic address: [email protected].
⁶ Department of Biochemistry and Molecular Biology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan. Electronic address: [email protected].
⁷ Department of Endodontology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan. Electronic address: [email protected].
⁸ Department of Endodontology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan. Electronic address: [email protected].
⁹ Department of Endodontology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan. Electronic address: [email protected].
¹⁰ Department of Biochemistry and Molecular Biology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan. Electronic address: [email protected].

PMID: 39832694
DOI: 10.1016/j.job.2025.100617

Abstract

Objectives: Low-level laser therapy (LLLT) using an erbium-doped yttrium aluminum garnet (Er:YAG) laser provides a non-invasive approach applicable to various dental treatments. Here, we investigated the effects of Er:YAG laser irradiation on human dental pulp stem cells (hDPSCs) in an in vitro experiment.

Methods: The hDPSCs were categorized into four groups: laser-irradiated with activators (VLT: activated vitamin D₃, bone morphogenetic protein receptor inhibitor, and transforming growth factor-beta (TGF-β)) (LLLT(+)VLT), laser-irradiated without activators (LLLT(+)-only), non-irradiated with activators (LLLT(-)VLT), and non-irradiated without activators (control). Cell proliferation, hard tissue differentiation, TGF-β signaling pathway activity, mineralization induction, and gene expression levels were assessed using several approaches, including cell proliferation assays, ALP assays, western blotting, Alizarin Red S staining, X-ray diffraction, and quantitative polymerase chain reaction.

Results: Cell proliferation was similar between the LLLT(+)-only and control groups. The ALP activity was significantly higher in LLLT(+)VLT group than in LLLT(-)VLT group (p < 0.05); however, it was suppressed by TGF-β signaling inhibitors. Western blotting showed enhanced SMAD3 phosphorylation in the LLLT(+)VLT group. The mineralization nodules and mRNA levels of matrix vesicle marker genes were significantly higher in LLLT(+)VLT group, and the nodules were partially composed of hydroxyapatite. The hard tissue formation marker gene expression in LLLT(+)VLT group was significantly higher (p < 0.05) than that in the LLLT(+)-only and control groups; however, it was unchanged or suppressed compared with that in LLLT(-)VLT group.

Conclusions: LLLT using an Er:YAG laser, combined with VLT, may promote the differentiation of hDPSCs into hard tissue-forming cells and enhance mineralization.

Keywords: dental pulp; lasers; low-level laser therapy; stem cells; transforming growth factor-beta.