title: Comparative transcriptomics reveals RhoE as a novel regulator of actin dynamics in bone-resorbing osteoclasts.
abstract: The function of osteoclasts (OCs), multinucleated giant cells (MGCs) of the monocytic lineage, is bone resorption. To resorb bone, OCs form podosomes. These are actin-rich adhesive structures that pattern into rings that drive OC migration and into "sealing-zones" (SZs) that confine the resorption lacuna. Although changes in actin dynamics during podosome patterning have been documented, the mechanisms that regulate these changes are largely unknown. From human monocytic precursors, we differentiated MGCs that express OC degradation enzymes but are unable to resorb the mineral matrix. We demonstrated that, despite exhibiting bona fide podosomes, these cells presented dysfunctional SZs. We then performed two-step differential transcriptomic profiling of bone-resorbing OCs versus nonresorbing MGCs to generate a list of genes implicated in bone resorption. From this list of candidate genes, we investigated the role of Rho/Rnd3. Using primary RhoE-deficient OCs, we demonstrated that RhoE is indispensable for OC migration and bone resorption by maintaining fast actin turnover in podosomes. We further showed that RhoE activates podosome component cofilin by inhibiting its Rock-mediated phosphorylation. We conclude that the RhoE-Rock-cofilin pathway, by promoting podosome dynamics and patterning, is central for OC migration, SZ formation, and, ultimately, bone resorption.
authors.affiliation: Institut de Génomique Fonctionnelle de Lyon, Université de Lyon, Université Lyon 1, CNRS, Ecole Normale Supérieure de Lyon, Lyon Cedex 07, France Laboratoire de Biologie Moléculaire de la Cellule, Université de Lyon, Université Lyon 1, CNRS, Ecole Normale Supérieure de Lyon, Lyon Cedex 07, France Departamento Medicina y Cirugía Animal, Facultad de Veterinaria, Universidad CEU Cardenal Herrera, 46115 Alfara del Patriarca, Valencia, Spain Plateau Technique Imagerie/Microscopie Facility, SFR Biosciences (UMS3444/US8), Ecole Normale Supérieure de Lyon, Lyon Cedex 07, France Laboratory of Cellular Pathology, 46012 Valencia, Spain Departamento Ciencias Biomédicas-Seminario Salud, 46113 Moncada, Valencia, Spain.
authors.forename: Dan
authors.initials: D
authors.lastname: Georgess
authors.forename: Marlène
authors.initials: M
authors.lastname: Mazzorana
authors.forename: José
authors.initials: J
authors.lastname: Terrado
authors.forename: Christine
authors.initials: C
authors.lastname: Delprat
authors.forename: Christophe
authors.initials: C
authors.lastname: Chamot
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Guasch
authors.forename: Ignacio
authors.initials: I
authors.lastname: Pérez-Roger
authors.forename: Pierre
authors.initials: P
authors.lastname: Jurdic
authors.forename: Irma
authors.initials: I
authors.lastname: Machuca-Gayet
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D051339:Actin Depolymerizing Factors / Q000378:metabolism; D000199:Actins / Q000378:metabolism*; D000577:Amides / Q000494:pharmacology; D000818:Animals; D001862:Bone Resorption / Q000235:genetics / Q000378:metabolism*; D002417:Cattle; D002454:Cell Differentiation / Q000235:genetics; D002465:Cell Movement; D002478:Cells, Cultured; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020869:Gene Expression Profiling; D015726:Giant Cells / Q000378:metabolism; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D010010:Osteoclasts / Q000378:metabolism*; D010766:Phosphorylation; D011725:Pyridines / Q000494:pharmacology; D059467:Transcriptome; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D051339:Actin Depolymerizing Factors; D000199:Actins; D000577:Amides; D004791:Enzyme Inhibitors; D011725:Pyridines; C108830:Y 27632; D054460:rho-Associated Kinases; C508705:RND3 protein, human; D020741:rho GTP-Binding Proteins