scholarly journals Rab11A Functions as a Negative Regulator of Osteoclastogenesis through Dictating Lysosome-Induced Proteolysis of c-fms and RANK Surface Receptors

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2384 ◽  
Author(s):  
Yuka Okusha ◽  
Manh Tien Tran ◽  
Mami Itagaki ◽  
Chiharu Sogawa ◽  
Takanori Eguchi ◽  
...  
Keyword(s):  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Osteoclast Formation ◽  
Negative Regulator ◽  
Immunocytochemical Staining ◽  
Nuclear Factor ◽  
Lysosomal Activity ◽  
Late Endosomes ◽  
Early Endosomes ◽  
Receptor Activator

Osteoclast differentiation and activity are controlled by two essential cytokines, macrophage colony-stimulating factor (M-CSF) and the receptor activator of nuclear factor-κB ligand (RANKL). Rab11A GTPase, belonging to Rab11 subfamily representing the largest branch of Ras superfamily of small GTPases, has been identified as one of the crucial regulators of cell surface receptor recycling. Nevertheless, the regulatory role of Rab11A in osteoclast differentiation has been completely unknown. In this study, we found that Rab11A was strongly upregulated at a late stage of osteoclast differentiation derived from bone marrow-derived macrophages (BMMs) or RAW-D murine osteoclast precursor cells. Rab11A silencing promoted osteoclast formation and significantly increased the surface levels of c-fms and receptor activator of nuclear factor-κB (RANK) while its overexpression attenuated osteoclast formation and the surface levels of c-fms and RANK. Using immunocytochemical staining for tracking Rab11A vesicular localization, we observed that Rab11A was localized in early and late endosomes, but not lysosomes. Intriguingly, Rab11A overexpression caused the enhancement of fluorescent intensity and size-based enlargement of early endosomes. Besides, Rab11A overexpression promoted lysosomal activity via elevating the endogenous levels of a specific lysosomal protein, LAMP1, and two key lysosomal enzymes, cathepsins B and D in osteoclasts. More importantly, inhibition of the lysosomal activity by chloroquine, we found that the endogenous levels of c-fms and RANK proteins were enhanced in osteoclasts. From these observations, we suggest a novel function of Rab11A as a negative regulator of osteoclastogenesis mainly through (i) abolishing the surface abundance of c-fms and RANK receptors, and (ii) upregulating lysosomal activity, subsequently augmenting the degradation of c-fms and RANK receptors, probably via the axis of early endosomes–late endosomes–lysosomes in osteoclasts.

MafB negatively regulates RANKL-mediated osteoclast differentiation

Blood ◽  
2006 ◽  
Vol 109 (8) ◽  
pp. 3253-3259 ◽  
Author(s):  
Kabsun Kim ◽  
Jung Ha Kim ◽  
Junwon Lee ◽  
Hye Mi Jin ◽  
Hyun Kook ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Transcription Factors ◽  
Phagocytic Activity ◽  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Osteoclast Formation ◽  
Nuclear Factor ◽  
Binding Ability ◽  
Receptor Activator ◽  
Macrophage Lineage

Abstract Receptor activator of nuclear factor κB ligand (RANKL) induces osteoclast formation from hematopoietic cells via regulation of various transcription factors. Here, we show that MafB negatively regulates RANKL-induced osteoclast differentiation. Expression levels of MafB are significantly reduced by RANKL during osteoclastogenesis. Overexpression of MafB in bone marrow-derived monocyte/macrophage lineage cells (BMMs) inhibits the formation of TRAP+ multinuclear osteoclasts, but phagocytic activity of BMMs is retained. Furthermore, overexpression of MafB in BMMs attenuates the gene induction of NFATc1 and osteoclast-associated receptor (OSCAR) during RANKL-mediated osteoclastogenesis. In addition, MafB proteins interfere with the DNA-binding ability of c-Fos, Mitf, and NFATc1, inhibiting their transactivation of NFATc1 and OSCAR. Furthermore, reduced expression of MafB by RNAi enhances osteoclastogenesis and increases expression of NFATc1 and OSCAR. Taken together, our results suggest that MafB can act as an important modulator of RANKL-mediated osteoclastogenesis.

An adherent condition is required for formation of multinuclear osteoclasts in the presence of macrophage colony-stimulating factor and receptor activator of nuclear factor κB ligand

Blood ◽  
2000 ◽  
Vol 96 (13) ◽  
pp. 4335-4343 ◽  
Author(s):  
Takeshi Miyamoto ◽  
Fumio Arai ◽  
Osamu Ohneda ◽  
Katsumasa Takagi ◽  
Dirk M. Anderson ◽  
...  
Keyword(s):  
Culture Medium ◽  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Precursor Cells ◽  
Osteoclast Precursor ◽  
Nuclear Factor ◽  
Receptor Activator ◽  
Multinuclear Cells ◽  
Differentiation And Proliferation

Abstract Identification of receptor activator of nuclear factor-κB (RANK) and RANK-ligand (RANKL) has provided new insights into the osteoclast differentiation pathway. Osteoclast precursor cells were isolated using monoclonal antibodies against c-Fms and RANK, and the effect of adherence on the in vitro differentiation and proliferation of these cells was examined in 2 different types of stromal-cell–free culture systems: a semisolid culture medium (a nonadherent system) and a liquid culture medium (an adherent system). Osteoclast precursor cells were not able to differentiate into mature osteoclasts efficiently in the semisolid culture system. Trimerized RANKL enhanced osteoclast differentiation in semisolid cultures, but not to the extent seen when cells were allowed to adhere to plastic. Initial precursor cells were capable of differentiating into macrophages or osteoclasts. Once these cells were transferred to adherent conditions, striking differentiation was induced. Multinuclear cells were observed even after they had displayed phagocytic activity, which suggests that cell adhesion plays an important role in the differentiation of osteoclast precursor cells. Integrins, especially the arginine-glycine-aspartic acid (RGD)–recognizing integrins αv and β3, were needed for osteoclast-committed precursor cells to proliferate in order to form multinuclear osteoclasts, and the increase in cell density affected the formation of multinuclear cells. A model of osteoclast differentiation with 2 stages of precursor development is proposed: (1) a first stage, in which precursor cells are bipotential and capable of anchorage-independent growth, and (2) a second stage, in which the further proliferation and differentiation of osteoclast-committed precursor cells is anchorage-dependent.

scholarly journals Interleukin-6 Inhibits Receptor Activator of Nuclear Factor κB Ligand-Induced Osteoclastogenesis by Diverting Cells into the Macrophage Lineage: Key Role of Serine727 Phosphorylation of Signal Transducer and Activator of Transcription 3

Endocrinology ◽  
2008 ◽  
Vol 149 (7) ◽  
pp. 3688-3697 ◽  
Author(s):  
Laurence Duplomb ◽  
Marc Baud’huin ◽  
Céline Charrier ◽  
Martine Berreur ◽  
Valérie Trichet ◽  
...  
Keyword(s):  
Osteoclast Differentiation ◽  
Nuclear Factor Κb ◽  
Mouse Bone Marrow ◽  
Nuclear Factor ◽  
Signal Transducer ◽  
Blood Monocytes ◽  
Receptor Activator ◽  
Few Data ◽  
Macrophage Lineage

Osteoclasts are bone-resorptive cells that differentiate from hematopoietic precursors upon receptor activator of nuclear factor κB ligand (RANKL) activation. Previous studies demonstrated that IL-6 indirectly stimulates osteoclastogenesis through the production of RANKL by osteoblasts. However, few data described the direct effect of IL-6 on osteoclasts. To investigate this effect, we used several models: murine RAW264.7 cells, mouse bone marrow, and human blood monocytes. In the three models used, the addition of IL-6 inhibited RANKL-induced osteoclastogenesis. Furthermore, IL-6 decreased the expression of osteoclast markers and up-modulated macrophage markers. To elucidate this inhibition, signal transducer and activator of transcription (STAT) 3, the main signaling molecule activated by IL-6, was analyzed. Addition of two STAT3 inhibitors completely abolished RANKL-induced osteoclastogenesis, revealing a key role of STAT3. We demonstrated that a basal level of phosphorylated-STAT3 on Serine727 associated with an absence of phosphorylation on Tyrosine705 is essential for osteoclastogenesis. Furthermore, a decrease of Serine727 phosphorylation led to an inhibition of osteoclast differentiation, whereas an increase of Tyrosine705 phosphorylation upon IL-6 stimulation led to the formation of macrophages instead of osteoclasts. In conclusion, we showed for the first time that IL-6 inhibits RANKL-induced osteoclastogenesis by diverting cells into the macrophage lineage, and demonstrated the functional role of activated-STAT3 and its form of phosphorylation in the control of osteoclastogenesis.

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