Rho-A Is Critical for Osteoclast Podosome Organization, Motility, and Bone Resorption

Chellaiah, Meenakshi A.; Soga, Norihito; Swanson, Suzanne; McAllister, Sandy; Alvarez, Ulises; Wang, Dongmei; Dowdy, Steven F.; Hruska, Keith A.

doi:10.1074/jbc.275.16.11993

Cited by 243 publications

(240 citation statements)

References 66 publications

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“…By contrast, concentrations of NE10790 that inhibited resorption (0.5-1 mM) had little effect on F-actin organization at the mineral surface, with no significant reduction in the number of F-actin rings. This is consistent with the evidence that regulation of the osteoclast cytoskeleton, required for bone resorption, involves small GTPases prenylated by GGTase I, such as Rho and Rac (16,(27)(28)(29). NE10790 specifically inhibits Rab prenylation by Rab GGTase, demonstrating for the first time that Rab proteins are also required for osteoclastic bone resorption.…”

Section: Figsupporting

confidence: 74%

Identification of a Novel Phosphonocarboxylate Inhibitor of Rab Geranylgeranyl Transferase That Specifically Prevents Rab Prenylation in Osteoclasts and Macrophages

Coxon

Helfrich²,

Larijani

et al. 2001

Journal of Biological Chemistry

159

162

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Nitrogen-containing bisphosphonate drugs inhibit bone resorption by inhibiting FPP synthase and thereby preventing the synthesis of isoprenoid lipids required for protein prenylation in bone-resorbing osteoclasts. NE10790 is a phosphonocarboxylate analogue of the potent bisphosphonate risedronate and is a weak antiresorptive agent. Although NE10790 was a poor inhibitor of FPP synthase, it did inhibit prenylation in J774 macrophages and osteoclasts, but only of proteins of molecular mass ϳ22-26 kDa, the prenylation of which was not affected by peptidomimetic inhibitors of either farnesyl transferase (FTI-277) or geranylgeranyl transferase I (GGTI-298). These 22-26-kDa proteins were shown to be geranylgeranylated by labelling J774 cells with [ 3 H]geranylgeraniol. Furthermore, NE10790 inhibited incorporation of [ 14 C]mevalonic acid into Rab6, but not into H-Ras or Rap1, proteins that are modified by FTase and GGTase I, respectively. These data demonstrate that NE10790 selectively prevents Rab prenylation in intact cells. In accord, NE10790 inhibited the activity of recombinant Rab GGTase in vitro, but did not affect the activity of recombinant FTase or GGTase I. NE10790 therefore appears to be the first specific inhibitor of Rab GGTase to be identified. In contrast to risedronate, NE10790 inhibited bone resorption in vitro without markedly affecting osteoclast number or the F-actin "ring" structure in polarized osteoclasts. However, NE10790 did alter osteoclast morphology, causing the formation of large intracellular vacuoles and protrusion of the basolateral membrane into large, "domed" structures that lacked microvilli. The anti-resorptive activity of NE10790 is thus likely due to disruption of Rabdependent intracellular membrane trafficking in osteoclasts.

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Section: Figsupporting

confidence: 74%

Identification of a Novel Phosphonocarboxylate Inhibitor of Rab Geranylgeranyl Transferase That Specifically Prevents Rab Prenylation in Osteoclasts and Macrophages

Coxon

Helfrich²,

Larijani

et al. 2001

Journal of Biological Chemistry

159

162

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“…In the former case it was membrane ruffles, whereas in the latter, it was in podosome rosettes, the major actin structures in Src-transformed fibroblasts. Podosome formation is known to be Rho GTPase-dependent (Chellaiah et al, 2000;Chellaiah, 2005;Osiak et al, 2005), and we found that RhoGDI was closely associated with RhoA in the rosettes ( Figure 6C). RhoGDI Y156E -expressing cells exhibited increased cell spreading, membrane ruffling, and motility compared with the suppression of these responses by wild-type RhoGDI or RhoGDI Y156F .…”

Section: Discussionmentioning

confidence: 64%

Phosphorylation of RhoGDI by Src Regulates Rho GTPase Binding and Cytosol-Membrane Cycling

DerMardirossian

Rocklin

Seo

et al. 2006

MBoC

151

144

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Rho GTPases (Rac, Rho, and Cdc42) play important roles in regulating cell function through their ability to coordinate the actin cytoskeleton, modulate the formation of signaling reactive oxidant species, and control gene transcription. Activation of Rho GTPase signaling pathways requires the regulated release of Rho GTPases from RhoGDI complexes, followed by their reuptake after membrane cycling. We show here that Src kinase binds and phosphorylates RhoGDI both in vitro and in vivo at Tyr156. Analysis of Rho GTPase-RhoGDI complexes using in vitro assays of complexation and in vivo by coimmunoprecipitation analysis indicates that Src-mediated phosphorylation of Tyr156 causes a dramatic decrease in the ability of RhoGDI to form a complex with RhoA, Rac1, or Cdc42. Phosphomimetic mutation of Tyr1563 Glu results in the constitutive association of RhoGDI Y156E with the plasma membrane and/or associated cortical actin. Substantial cortical localization of tyrosine-phosphorylated RhoGDI is also observed in fibroblasts expressing active Src, where it is most evident in podosomes and regions of membrane ruffling. Expression of membrane-localized RhoGDI Y156E mutant is associated with enhanced cell spreading and membrane ruffling. These results suggest that Src-mediated RhoGDI phosphorylation is a novel physiological mechanism for regulating Rho GTPase cytosol membrane-cycling and activity. INTRODUCTIONThe Rho GTPases regulate cellular activities that include growth and differentiation, vesicular transport, production of reactive oxygen species (ROS), apoptosis, cell motility, and various other aspects of cytoskeletal dynamics and cell polarity (Van Aelst and Souza-Schorey, 1997;Bishop and Hall, 2000). Rho GTPases function as molecular switches in cell signaling, alternating between inactive GDP-bound states maintained as cytosolic complexes with GDP dissociation inhibitors (GDIs), and active GTP-bound states usually associated with membranes where effector targets reside. Complexation of Rho, Rac, or Cdc42 with GDIs inhibits GDP dissociation and localizes GTPases to the cytosol in inert forms unable to interact with GEFs (guanine nucleotide exchange factors), GAPs (GTPase activating proteins), or effector targets (Van Aelst and Souza-Schorey, 1997;DerMardirossian and Bokoch, 2005). GDIs maintain Rho GTPases as soluble cytosolic proteins by forming high-affinity complexes that mask the C-terminal geranylgeranyl membrane-targeting moiety within a hydrophobic pocket formed by the immunoglobulin-like domain of RhoGDI (Gosser et al., 1997;Keep et al., 1997;Hoffman et al., 2000). When Rho proteins are released from GDIs, they insert into the membrane lipid bilayer through their isoprenylated and polybasic C-terminal domains to be activated by membrane-associated GEFs, initiating the association with effector targets at the membrane. A reassociation with GDI, possibly associated with GTP hydrolysis, is postulated to induce recycling of the GTPase to the cytosol. Regulation of the cytosol-membrane cycling of the Rho GTPase by G...

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“…However, miR‐31a‐5p reduction in the supernatant not only led to decreased osteoclastogenesis and bone resorption but also elevated expression of RhoA. Although studies have demonstrated that RhoA activity, controlling cytoskeleton organization, is crucial for osteoclast maturation and bone resorption (Chellaiah et al., 2000), it has also been reported that inhibition of RhoA maintained the podosomal and sealing zone stability, which is possibly correlated with increased microtubule acetylation and stabilization in osteoclasts (Destaing et al., 2005; Granot‐Attas, Luxenburg, Finkelshtein, & Elson, 2009; Ory, Brazier, Pawlak, & Blangy, 2008; Wu et al., 2017). In our study, increased RhoA expression through miR‐31a‐5p inhibition reduced osteoclastogenesis, while decreased RhoA expression favored osteoclastogenesis.…”

Section: Discussionmentioning

confidence: 91%

MicroRNA‐31a‐5p from aging BMSCs links bone formation and resorption in the aged bone marrow microenvironment

et al. 2018

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The alteration of age‐related molecules in the bone marrow microenvironment is one of the driving forces in osteoporosis. These molecules inhibit bone formation and promote bone resorption by regulating osteoblastic and osteoclastic activity, contributing to age‐related bone loss. Here, we observed that the level of microRNA‐31a‐5p (miR‐31a‐5p) was significantly increased in bone marrow stromal cells (BMSCs) from aged rats, and these BMSCs demonstrated increased adipogenesis and aging phenotypes as well as decreased osteogenesis and stemness. We used the gain‐of‐function and knockdown approach to delineate the roles of miR‐31a‐5p in osteogenic differentiation by assessing the decrease of special AT‐rich sequence‐binding protein 2 (SATB2) levels and the aging of BMSCs by regulating the decline of E2F2 and recruiting senescence‐associated heterochromatin foci (SAHF). Notably, expression of miR‐31a‐5p, which promotes osteoclastogenesis and bone resorption, was markedly higher in BMSCs‐derived exosomes from aged rats compared to those from young rats, and suppression of exosomal miR‐31a‐5p inhibited the differentiation and function of osteoclasts, as shown by elevated RhoA activity. Moreover, using antagomiR‐31a‐5p, we observed that, in the bone marrow microenvironment, inhibition of miR‐31a‐5p prevented bone loss and decreased the osteoclastic activity of aged rats. Collectively, our results reveal that miR‐31a‐5p acts as a key modulator in the age‐related bone marrow microenvironment by influencing osteoblastic and osteoclastic differentiation and that it may be a potential therapeutic target for age‐related osteoporosis.

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Rho-A Is Critical for Osteoclast Podosome Organization, Motility, and Bone Resorption

Cited by 243 publications

References 66 publications

Identification of a Novel Phosphonocarboxylate Inhibitor of Rab Geranylgeranyl Transferase That Specifically Prevents Rab Prenylation in Osteoclasts and Macrophages

Identification of a Novel Phosphonocarboxylate Inhibitor of Rab Geranylgeranyl Transferase That Specifically Prevents Rab Prenylation in Osteoclasts and Macrophages

Phosphorylation of RhoGDI by Src Regulates Rho GTPase Binding and Cytosol-Membrane Cycling

MicroRNA‐31a‐5p from aging BMSCs links bone formation and resorption in the aged bone marrow microenvironment

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