Open AccessOsteoclasts Modulate Bone Erosion in Cholesteatoma via RANKL Signaling
Author(s) -
Ryusuke Imai,
Takashi Sato,
Yasuhiro Iwamoto,
Yukiko Hanada,
Mineko Terao,
Yumi Ohta,
Yasuhiro Osaki,
Toshio Imai,
Tetsuo Morihana,
Suzuyo Okazaki,
Koichiro Oshima,
Daisuke Okuzaki,
Ichiro Katayama,
Hidenori Inohara
Publication year - 2019
Publication title -
journal of the association for research in otolaryngology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.498
H-Index - 72
eISSN - 1525-3961
pISSN - 1438-7573
DOI - 10.1007/s10162-019-00727-1
Subject(s) - cholesteatoma , rankl , osteoclast , bone erosion , medicine , pathology , cancer research , tumor necrosis factor alpha , bone resorption , microbiology and biotechnology , receptor , rheumatoid arthritis , biology , immunology , activator (genetics) , surgery
Cholesteatoma starts as a retraction of the tympanic membrane and expands into the middle ear, eroding the surrounding bone and causing hearing loss and other serious complications such as brain abscess and meningitis. Currently, the only effective treatment is complete surgical removal, but the recurrence rate is relatively high. In rheumatoid arthritis (RA), osteoclasts are known to be responsible for bone erosion and undergo differentiation and activation by receptor activator of NF-κB ligand (RANKL), which is secreted by synovial fibroblasts, T cells, and B cells. On the other hand, the mechanism of bone erosion in cholesteatoma is still controversial. In this study, we found that a significantly larger number of osteoclasts were observed on the eroded bone adjacent to cholesteatomas than in unaffected areas, and that fibroblasts in the cholesteatoma perimatrix expressed RANKL. We also investigated upstream transcription factors of RANKL using RNA sequencing results obtained via Ingenuity Pathways Analysis, a tool that identifies relevant targets in molecular biology systems. The concentrations of four candidate factors, namely interleukin-1β, interleukin-6, tumor necrosis factor α, and prostaglandin E2, were increased in cholesteatomas compared with normal skin. Furthermore, interleukin-1β was expressed in infiltrating inflammatory cells in the cholesteatoma perimatrix. This is the first report demonstrating that a larger-than-normal number of osteoclasts are present in cholesteatoma, and that the disease involves upregulation of factors related to osteoclast activation. Our study elucidates the molecular basis underlying bone erosion in cholesteatoma.