RESUMEN
Cellularity, viability and immunophenotype of mononuclear cells derived from the tibial marrow of C57bL/6 mice were measured after the 30-day "Bion-M1" space flight and subsequent 7-day recovery. Cell number in the flight group was significantly less than in the group of vivarium control. There was no difference in the parameter between the flight and control groups after the recovery. Viability of mononuclear cells was more than 95% in all examined groups. Flow cytometric analysis failed to show differences in bone marrow cell immunophenotype (CD45, CD34, CD90.1 (Thy1); however, the flight animals had more large-sized CD45+ mononuclears than the control groups of mice. These results indicate that spaceflight factors did not have significant damaging effects on the number or immunophenotype of murine bone marrow mononuclears. These observations are consistent with the previously made assumption of a moderate and reversible stress reaction of mammals to space flight.
Asunto(s)
Células de la Médula Ósea/citología , Leucocitos Mononucleares/citología , Vuelo Espacial , Tibia/citología , Adaptación Fisiológica , Animales , Antígenos CD/inmunología , Densidad Ósea , Células de la Médula Ósea/inmunología , Supervivencia Celular , Femenino , Inmunofenotipificación , Leucocitos Mononucleares/inmunología , Ratones , Tibia/inmunología , IngravidezRESUMEN
BACKGROUND AND PURPOSE: Airway remodelling in asthma is manifested, in part, as increased airway smooth muscle (ASM) mass, reflecting myocyte proliferation. We hypothesized that calcitriol, a secosteroidal vitamin D receptor (VDR) modulator, would inhibit growth factor-induced myocyte proliferation. EXPERIMENTAL APPROACH: Human ASM cell cultures were derived from bronchial samples taken during surgery. ASM cells were treated with platelet-derived growth factor (PDGF) (10 ng.mL(-1)) for 24 h in the presence of calcitriol, dexamethasone or a checkpoint kinase 1 (Chk1) inhibitor (SB218078). The effects of calcitriol on PDGF-mediated cell proliferation were assessed by thymidine incorporation assay, propidium iodide-based cell cycle analysis, caspase-3 assay and immunoblotting for specific cell cycle modulators. KEY RESULTS: Calcitriol, but not dexamethasone, inhibited PDGF-induced ASM DNA synthesis concentration dependently (IC(50)= 520 +/- 52 nM). These effects were associated with VDR-mediated expression of cytochrome CYP24A1 with no effects on ASM apoptosis. Calcitriol substantially inhibited (P < 0.01) PDGF-stimulated cell growth in ASM derived from both normal (59 +/- 8%) and asthmatic subjects (57 +/- 9%). Calcitriol inhibited PDGF-induced phosphorylation of retinoblastoma protein (Rb) and Chk1, with no effects on PDGF-mediated activation of extracellular signal-regulated kinases 1/2, PI3-kinase and S6 kinase, or expression of p21(Waf/Cip-1), p27(Kip1), cyclin D and E2F-1. Consistent with these observations, SB218078 also inhibited (IC(50)= 450 +/- 100 pM) PDGF-induced cell cycle progression. CONCLUSIONS AND IMPLICATIONS: Calcitriol decreased PDGF-induced ASM cell growth by inhibiting Rb and Chk1 phosphorylation.
Asunto(s)
Remodelación de las Vías Aéreas (Respiratorias)/efectos de los fármacos , Calcitriol/farmacología , Miocitos del Músculo Liso/efectos de los fármacos , Vitaminas/farmacología , Adulto , Asma/tratamiento farmacológico , Asma/fisiopatología , Bronquios/citología , Bronquios/metabolismo , Calcitriol/administración & dosificación , Proliferación Celular/efectos de los fármacos , Células Cultivadas , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1) , Dexametasona/farmacología , Femenino , Glucocorticoides/farmacología , Humanos , Concentración 50 Inhibidora , Masculino , Persona de Mediana Edad , Miocitos del Músculo Liso/metabolismo , Fosforilación/efectos de los fármacos , Factor de Crecimiento Derivado de Plaquetas/farmacología , Proteínas Quinasas/efectos de los fármacos , Proteínas Quinasas/metabolismo , Proteína de Retinoblastoma/efectos de los fármacos , Proteína de Retinoblastoma/metabolismo , Vitaminas/administración & dosificaciónRESUMEN
The role of myosin-binding in cytoskeletal arrangement of non-muscle low molecular weight caldesmon (l-caldesmon) was studied. The N-terminal myosin-binding domain of caldesmon N152 colocalized with myosin in transiently transfected chicken fibroblasts. When added exogenously to the Triton-insoluble cytoskeleton, N152 enhanced l-caldesmon displacement by exogenous C-terminal actin-binding fragment (H1). Thus, a significant fraction of l-caldesmon cross-links actin and myosin. In contrast, in epithelioid HeLa cells most of l-caldesmon was only actin-bound as H1 alone was enough for its displacement. Phosphorylation by mitogen-activated protein kinase reduced the capability of H1 to displace endogenous l-caldesmon, suggesting it may represent a regulatory mechanism for actin-caldesmon interaction in vivo.
Asunto(s)
Actomiosina/metabolismo , Proteínas de Unión a Calmodulina/metabolismo , Fibroblastos/metabolismo , Actinas/metabolismo , Animales , Unión Competitiva/efectos de los fármacos , Unión Competitiva/fisiología , Proteínas de Unión a Calmodulina/genética , Proteínas de Unión a Calmodulina/farmacología , Células Cultivadas , Pollos , Reactivos de Enlaces Cruzados/farmacología , Citoesqueleto/metabolismo , Fibroblastos/citología , Células HeLa/citología , Células HeLa/metabolismo , Humanos , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Quinasas Activadas por Mitógenos/farmacología , Mutagénesis Sitio-Dirigida , Miosinas/metabolismo , Fragmentos de Péptidos/genética , Fragmentos de Péptidos/farmacología , Fosforilación/efectos de los fármacos , Estructura Terciaria de Proteína/fisiología , TransfecciónAsunto(s)
Movimiento Celular , Proteína Quinasa 1 Activada por Mitógenos/fisiología , Proteínas Quinasas Activadas por Mitógenos/fisiología , Músculo Liso/citología , Activador de Plasminógeno de Tipo Uroquinasa/fisiología , Células Cultivadas , Humanos , Kringles , Músculo Liso/enzimología , Músculo Liso/metabolismo , Mutación , Cadenas Ligeras de Miosina/metabolismo , Fosforilación , Proteínas Recombinantes/farmacología , Activador de Plasminógeno de Tipo Uroquinasa/genética , Activador de Plasminógeno de Tipo Uroquinasa/farmacología , Proteínas Quinasas p38 Activadas por MitógenosRESUMEN
The recombinant urokinase plasmogen activator (r-uPA) activated migration of the smooth muscle cells whereas the uPA mutant containing an altered growth factor-like domain (GFD) was ineffective. The uPA seems to possess properties of the urokinase receptor antagonist.