IL-34 Plays a Role for Differentiation of Osteoclasts in Inflammatory Destruction of Alveolar Bone

Kawabe, Mutsuki

IL-34 Plays a Role for Differentiation of Osteoclasts in Inflammatory Destruction of Alveolar Bone

Mutsuki Kawabe , Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Japan

Masahiro Urade PhD, Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Japan

Kazuma Noguchi PhD, Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Japan

Kazuki Takaoka PhD, Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Japan

Yusuke Zushi PhD, Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Japan

Kyohei Yoshikawa , Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Japan

Hiromitsu Kishimoto PhD, Oral and Maxillofacial Surgery, Hyogo College of Medicine, Nishinomiya, Japan

Introduction: Periodontitis and osteomyelitisis are infectious inflammatory diseases caused by periodontopathic bacteria. TNF-α represents pro-inflammatory cytokines and plays a major role in host defense, and it affects pro-inflammatory activities through various cells. Periodontal ligaments (PDL) are connective tissue between alveolar bone and cementum. IL-34 strongly binds to CSF-1R and promotes the differentiation, proliferation, and survival of mononuclear phagocyte lineage cells such as monocytes, macrophages, and osteoclasts as M-CSF does. In this study, to elucidate the involvement of IL-34 in periodontal biology, we evaluated the gene expression levels and the protein levels of IL-34 in PDL cells affected by TNF-α.

Materials and methods: Human PDL (hPDL) cells were isolated from PDLs tissue of patients undergoing extraction of premolars. We treated hPDL cells without or with the concentration of 0.1, 1, 10 ng/mL TNF-α for 48 hours. We accomplished analyses by using quantitative real-time PCR analysis and ELISA.

Results: IL-34 mRNA expression was increased in a dose-dependent manner of TNF-α. In particular by TNF-α above 1 ng/mL, IL-34 mRNA expression was determined highly. Furthermore the release of IL-34 protein from hPDL cells were detected in a dose-dependent manner of TNF-α.

Conclusion: It is likely that IL-34 plays a significant role for differentiation of osteoclasts in inflammatory bone destruction of alveolar bone and could constitute a new therapeutic target. We need further research to reveal a role of IL-34 in the inflammatory process associated with Periodontitis.