Alkali-treated titanium dioxide promotes formation of proteoglycan layer and altered calcification and immunotolerance capacity in bone marrow stem cell

Tomomi Mizutani; Shuhei Tsuchiya; Masaki Honda; Jorge Luis Montenegro Raudales; Kensuke Kuroda; Hironori Miyamoto; Tomohisa Nakamura; Kenichiro Ishibashi; Yasuyuki Shibuya

doi:10.1016/j.bbrep.2023.101569

Alkali-treated titanium dioxide promotes formation of proteoglycan layer and altered calcification and immunotolerance capacity in bone marrow stem cell

Biochem Biophys Rep. 2023 Nov 9:36:101569. doi: 10.1016/j.bbrep.2023.101569. eCollection 2023 Dec.

Authors

Tomomi Mizutani¹, Shuhei Tsuchiya¹, Masaki Honda², Jorge Luis Montenegro Raudales², Kensuke Kuroda³, Hironori Miyamoto¹, Tomohisa Nakamura¹, Kenichiro Ishibashi¹, Yasuyuki Shibuya¹

Affiliations

¹ Department of Oral Maxillofacial Surgery, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi Mizuho-cho Mizuho-ku, Nagoya, Aichi, 467-8602, Japan.
² Department of Oral Anatomy, School of Dentistry, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya, Aichi, 470-0131, Japan.
³ EcoTopia Science Institute, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8603, Japan.

Abstract

Introduction: In this study, we report that a proteoglycans (PGs)-layer between the bone and titanium dioxide (TiO₂) surface after osseointegration improved the calcification capacity and immunotolerance of human bone marrow mesenchymal stem cells (hBMSCs) on TiO₂. Alkaline treatment of TiO₂ is a method for promoting osteogenesis in hBMSCs. We hypothesized that promotion of osteogenesis due to alkaline treatment was caused by changing PGs-layer on TiO₂.

Objective: This study aimed to analyze whether alkaline treatment of TiO₂ affects PGs-layer formation and immunotolerance in hBMSCs.

Methods: The topology and wettability of the alkaline-treated titanium (Ti-Al) and unprocessed titanium (Ti-MS) surfaces were characterized. Initial cell attachment, cell proliferation, calcification capacity, alkaline phosphatase activity, PGs-layer formation, PGs function, and the expression of osteogenic and immunotolerance-related genes were analyzed. The conditioned medium (CM) from hBMSCs grown on Ti-Al and Ti-MS was added to macrophages (hMps) and Jurkat cells, and immunotolerance gene expression in these cells was analyzed.

Results: hBMSCs cultured on Ti-Al showed increased initial cell attachment, cell proliferation, PG-layer formation, and osteogenic capacity compared with hBMSCs on Ti-MS. Gene expression of indoleamine 2,3-dioxygenase (IDO) in the hBMSCs cultured on Ti-Al was higher than that in the hBMSCs on Ti-MS. CM from hBMSCs did not affect markers of M1 and M2 macrophages in hMps. CM from hBMSCs cultured on Ti-Al altered the gene expression of Foxp3 in Jurkat cells compared to that of CM from hBMSCs on Ti-MS.

Significance: These results suggest that alkaline treatment of TiO₂ altered PGs-layer formation, and changed the osteogenesis and immunotolerance of hBMSCs.

Keywords: Alkaline treatment; Bone marrow stem cells; Immunotolerance; Macrophage; Proteoglycan; T-cell; Titanium dioxide.