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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Research Article Bone biology

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 5

Increased IGF1 expression by MVNP-expressing OCLs.

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Increased IGF1 expression by MVNP-expressing OCLs. (A) Bone lysates were...
(A) Bone lysates were analyzed for IGF1 expression. (B) OCLs formed by CD11b+ cells from 8-month-old WT, MVNP, and p62-KI mice were analyzed for IGF1 expression. (C) Vertebral sections from 12-month-old WT, p62-KI, and MVNP mice were stained with anti-IGF1 or control IgG. Only OCLs from MVNP mice positively stained for IGF1. Original magnification, ×400. (D) IGF1 expression in OCLs from normal donors or patients with PD. The results shown in D are derived from the same gel shown in Figure 2. (E) IGF1 levels in OCL-conditioned media using an ELISA kit. Results represent the mean of 5 technical replicates from 2 biological replicates. (F) EphrinB2 and NFATc-1 expression in OCLs formed by CD11b+ cells treated with IGF1 for 4 days. (G) OCLs from PD patients were cultured with anti-IGF1 for 48 hours and the cell lysates assayed for ephrinB2 expression. (H) IGF1R expression on OCLs formed by CD11b+ cells were prepared as in B. (I) OBs were prepared as described previously (26), cultured with IGF1 for 3 days, and analyzed for EphB4 or Runx2 expression. Results for Figure 5 (except E) are representative of 3 biological replicates. The basal ratio of every molecule/loading control for vehicle treatment of WT cells was set at 1.0 in A, B, D, and F–I. Staining of OCLs from MVNP and WT mice (scored as positive or negative) showed positive anti-IGF1 staining in OCLs from MVNP, but not WT, mice.