Measles virus nucleocapsid protein increases osteoblast differentiation in Paget’s disease
Jumpei Teramachi, … , Noriyoshi Kurihara, G. David Roodman
Jumpei Teramachi, … , Noriyoshi Kurihara, G. David Roodman
Published February 15, 2016
Citation Information: J Clin Invest. 2016;126(3):1012-1022. https://doi.org/10.1172/JCI82012.
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Measles virus nucleocapsid protein increases osteoblast differentiation in Paget’s disease

Abstract

Paget’s disease (PD) is characterized by focal and dramatic bone resorption and formation. Treatments that target osteoclasts (OCLs) block both pagetic bone resorption and formation; therefore, PD offers key insights into mechanisms that couple bone resorption and formation. Here, we evaluated OCLs from 3 patients with PD and determined that measles virus nucleocapsid protein (MVNP) was expressed in 70% of these OCLs. Moreover, transgenic mice with OCL-specific expression of MVNP (MVNP mice) developed PD-like bone lesions that required MVNP-dependent induction of high IL-6 expression levels in OCLs. In contrast, mice harboring a knockin of p62P394L (p62-KI mice), which is the most frequent PD-associated mutation, exhibited increased bone resorption, but not formation. Evaluation of OCLs from MVNP, p62-KI, and WT mice revealed increased IGF1 expression in MVNP-expressing OCLs that resulted from the high IL-6 expression levels in these cells. IL-6, in turn, increased the expression of coupling factors, specifically ephrinB2 on OCLs and EphB4 on osteoblasts (OBs). IGF1 enhanced ephrinB2 expression on OCLs and OB differentiation. Importantly, ephrinB2 and IGF1 levels were increased in MVNP-expressing OCLs from patients with PD and MVNP-transduced human OCLs compared with levels detected in controls. Further, anti-IGF1 or anti-IGF1R blocked Runx2 and osteocalcin upregulation in OBs cocultured with MVNP-expressing OCLs. These results suggest that in PD, MVNP upregulates IL-6 and IGF1 in OCLs to increase ephrinB2-EphB4 coupling and bone formation.

Authors

Jumpei Teramachi, Yuki Nagata, Khalid Mohammad, Yuji Inagaki, Yasuhisa Ohata, Theresa Guise, Laëtitia Michou, Jacques P. Brown, Jolene J. Windle, Noriyoshi Kurihara, G. David Roodman

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Figure 3

Effects of ephrinB2-Fc or EphB4-Fc on OB and OCL differentiation.

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Effects of ephrinB2-Fc or EphB4-Fc on OB and OCL differentiation. (A) OB...
(A) OB precursors from WT and MVNP mice were treated with ephrinB2-Fc for 4 days and analyzed for p-ERK1/2, osterix, and Runx2. (B) OBs from WT and MVNP mice were cultured with control-Fc or ephrinB2-Fc and stained for ALP or alizarin red (26). ALP and alizarin red staining was quantitated by ImageJ software. The values for cultures treated with IgG-Fc were set at 1. Original magnification, ×1. (C) Cocultures of OBs and OCLs from WT and MVNP mice were treated with EphB4-Fc for 3 days and then analyzed for Runx2 or NFATc1 expression. (D) CD11b+ cells from WT and MVNP mice were cultured with M-CSF, followed by 1,25-(OH)2D3 or RANKL and EphB4-Fc or IgG-Fc and stained for TRACP. Data represent the mean ± SD. *P < 0.01 compared with cultures with IgG-Fc using 1-way ANOVA. (E) Resorption pits formed on dentin slices by OCLs cultured with 1,25-(OH)2D3 or RANKL with or without EphB4-Fc. Original magnification, ×250. Data are expressed as the percentage of resorption area (mean ± SD; n = 4 technical replicates). *P < 0.01 compared with control cultures using a 2-tailed, unpaired Student’s t test. (F) CD11b+ cells were cultured with EphB4-Fc or control IgG-Fc as described in Methods. Cell lysates were analyzed for c-Fos, NFATc1, TRACP, cathepsin K, TRAF6, and Vav3. Protein expression levels in Figure 3 were compared with β-actin or GAPDH by densitometry. The value of the ratio obtained in lysates from untreated WT OCLs compared with β-actin or GAPDH was arbitrarily set at 1. Results for Figure 3 (except E) are representative of 3 biological replicates.