Abstract
Bone absorption is necessary for the maintenance of bone homeostasis. An osteoclast (OC) is a monocyte–macrophage lineage cell that absorbs bone tissue. Extracellular signal-regulated kinases (ERKs) are known to play important roles in regulating OC growth and differentiation. In this study, we examined specific downstream signal pathways affected by ERK inhibition during OC differentiation. Our results showed that the ERK inhibitors PD98059 and U0126 increased receptor activator of NF-κB ligand (RANKL)-induced OC differentiation in RAW 264.7 cells, implying a negative role in OC differentiation. This is supported by the effect of ERK2-specific small interfering RNA on increasing OC differentiation. In contrast to our findings regarding the RAW 264.7 cells, the ERK inhibitors attenuated the differentiation of bone marrow-derived cells into OCs. The ERK inhibitors significantly increased the phosphorylation of adenosine 5′-monophosphate-activated protein kinase (AMPK) but not the activation of p38 MAPK, Lyn, and mTOR. In addition, while the ERK inhibition increased the expression of the RANKL receptor RANK, it decreased the expression of negative mediators of OC differentiation, such as interferon regulatory factor-8, B-cell lymphoma 6, and interferon-γ. These dichotomous effects of ERK inhibition suggest that while ERKs may play positive roles in bone marrow-derived cells, ERKs may also play negative regulatory roles in RAW 264.7 cells. These data provide important information for drug development utilizing ERK inhibitors in OC-related disease treatment.
Funder
National Research Foundation of Korea
Subject
Inorganic Chemistry,Organic Chemistry,Physical and Theoretical Chemistry,Computer Science Applications,Spectroscopy,Molecular Biology,General Medicine,Catalysis
Reference58 articles.
1. Bone quality-the material and structural basis of bone strength and fragility;Seeman;N. Engl. J. Med.,2006
2. Coupling signals between the osteoclast and osteoblast: How are messages transmitted between these temporary visitors to the bone surface?;Sims;Front. Endocrinol.,2015
3. Osteoblast-osteoclast interactions;Chen;Connect. Tissue Res.,2018
4. Zhu, S., Ehnert, S., Roub, M., Häussling, V., Aspera, R.H., Chen, T., and Nussler, A.K. From the clinical problem to the basic research: Co-culture models of osteoblasts and osteoclasts. Int. J. Mol. Sci., 2018. 19.
5. Osteocyte-driven bone remodeling;Bellido;Calcif. Tissue Int.,2014
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