title: Different levels of the neuronal nitric oxide synthase isoform modulate the rate of osteoclastic differentiation of TIB-71 and CRL-2278 RAW 264.7 murine cell clones.
abstract: It has been clearly established that osteoclasts, which play a crucial role in bone resorption, differentiate from hematopoietic cells belonging to the monocyte/macrophage lineage in the presence of macrophage-colony stimulating factor (M-CSF) and receptor activator of NF-kappaB ligand (RANKL). We have here investigated the M-CSF- and RANKL-induced osteoclastic differentiation of two distinct clones of the murine monocytic/macrophagic RAW 264.7 cell line, known as TIB-71 and CRL-2278, the latter cell clone being defective for the expression of the inducible nitric oxide synthase isoform in response to interferon-gamma or lipopolysaccharide. CRL-2278 cells demonstrated a more rapid osteoclastic differentiation than TIB-71 cells, as documented by morphology, tartrate-resistant acid phosphatase positivity, and bone resorption activity. The enhanced osteoclastic differentiation of CRL-2278 was accompanied by a higher rate of cells in the S/G2-M phases of cell cycle as compared to TIB-71. The analysis of nitric oxide synthase (NOS) isoforms clearly demonstrated that only neuronal NOS was detectable at high levels in CRL-2278 but not in TIB cells under all tested conditions. Moreover, the broad inhibitor of NOS activity L-NAME significantly inhibited osteoclastic differentiation of CRL-2278 cells. Altogether, these results demonstrate that a basal constitutive neuronal NOS activity positively affects the RANKL/M-CSF-related osteoclastic differentiation.
authors.affiliation: Department of Normal Human Morphology, University of Trieste, Trieste, Italy. nicolin@units.it
authors.forename: Vanessa
authors.initials: V
authors.lastname: Nicolin
authors.forename: Cristina
authors.initials: C
authors.lastname: Ponti
authors.forename: Paola
authors.initials: P
authors.lastname: Narducci
authors.forename: Vittorio
authors.initials: V
authors.lastname: Grill
authors.forename: Roberta
authors.initials: R
authors.lastname: Bortul
authors.forename: Marina
authors.initials: M
authors.lastname: Zweyer
authors.forename: Mauro
authors.initials: M
authors.lastname: Vaccarezza
authors.forename: Giorgio
authors.initials: G
authors.lastname: Zauli
mesh_terms: D000135:Acid Phosphatase / Q000378:metabolism; D000818:Animals; D001862:Bone Resorption / Q000188:drug therapy; D002352:Carrier Proteins / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D045744:Cell Line, Tumor; D002999:Clone Cells; D007527:Isoenzymes / Q000378:metabolism; D016173:Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D008562:Membrane Glycoproteins / Q000494:pharmacology; D051379:Mice; D052248:Nitric Oxide Synthase Type I / Q000378:metabolism*; D010010:Osteoclasts / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; D000071681:Tartrate-Resistant Acid Phosphatase
chemical_list: D002352:Carrier Proteins; D007527:Isoenzymes; D008562:Membrane Glycoproteins; D053245:RANK Ligand; D053246:Receptor Activator of Nuclear Factor-kappa B; C505687:Tnfrsf11a protein, mouse; C505689:Tnfsf11 protein, mouse; D016173:Macrophage Colony-Stimulating Factor; D052248:Nitric Oxide Synthase Type I; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase