RESUMEN
α2-antiplasmin (α2AP) is known to be a physiological inhibitor of plasmin. Previously, we showed that α2AP displays various functions, such as promotion of extracellular matrix production, cell growth, and cell differentiation that are not promoted by its function as a plasmin inhibitor. We herein investigated the role of α2AP in bone formation by examining calcein incorporation after its injection in α2AP-deficient mice. We found that α2AP deficiency enhanced the bone formation rate in mice. We also found that the osteocalcin expression and alkaline phosphatase activity were elevated in the femur and serum of the α2AP-deficient mice. Intriguingly, α2AP deficiency promoted osteoblast (OB) differentiation of primary calvarial OBs. In contrast, α2AP attenuated OB differentiation of mouse osteoblastic the MC3T3-E1 cells. Furthermore, α2AP attenuated Wnt-3a-induced ß-catenin expression and lowdensity lipoprotein receptor-related protein 6 activation in the MC3T3-E1 cells. These results suggest that α2AP negatively affects OB differentiation and function by inhibiting the Wnt/ß-catenin pathway. These findings provide a basis for clinical strategies to improve various bone disorders.
Asunto(s)
Diferenciación Celular , Osteoblastos/metabolismo , Osteogénesis , Vía de Señalización Wnt , alfa 2-Antiplasmina/metabolismo , Animales , Línea Celular , Ratones , Ratones Noqueados , Proteína Wnt3A/genética , Proteína Wnt3A/metabolismo , alfa 2-Antiplasmina/genética , beta Catenina/genética , beta Catenina/metabolismoRESUMEN
Chronic inflammatory diseases, such as rheumatoid arthritis and periodontitis-caused bone destruction, results from an increase of bone-resorbing osteoclasts (OCs) induced by inflammation. However, the detailed mechanisms underlying this disorder remain unclear. We herein investigated that the effect of urokinase-type plasminogen activator (uPA) on inflammatory osteoclastogenesis induced by lipopolysaccharide (LPS), which is a potent stimulator of bone resorption in inflammatory diseases. We found that the uPA deficiency promoted inflammatory osteoclastogenesis and bone loss induced by LPS. We also showed that LPS induced the expression of uPA, and the uPA treatment attenuated the LPS-induced inflammatory osteoclastogenesis of RAW264.7 mouse monocyte/macrophage lineage cells. Additionally, we showed that the uPA-attenuated inflammatory osteoclastgenesis is associated with the activation of plasmin/protease-activated receptor (PAR)-1 axis by uPA. Moreover, we examined the mechanism underlying the effect of uPA on inflammatory osteoclastogenesis, and found that uPA/plasmin/PAR-1 activated the adenosine monophosphate-activated protein kinase (AMPK) pathway through Ca2+/calmodulin dependent protein kinase kinase (CaMKK) activation, and attenuated inflammatory osteoclastogenesis by inactivation of NF-κB in RAW264.7 cells. These data suggest that uPA attenuated inflammatory osteoclastogenesis through the plasmin/PAR-1/Ca2+/CaMKK/AMPK axis. Our findings may provide a novel therapeutic approach to bone loss caused by inflammatory diseases.
Asunto(s)
Quinasa de la Proteína Quinasa Dependiente de Calcio-Calmodulina/metabolismo , Fibrinolisina/metabolismo , Lipopolisacáridos/farmacología , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Osteoclastos/citología , Osteoclastos/efectos de los fármacos , Receptor PAR-1/metabolismo , Activador de Plasminógeno de Tipo Uroquinasa/farmacología , Animales , Diferenciación Celular/efectos de los fármacos , Línea Celular , Ratones , Transducción de Señal/efectos de los fármacos , Activador de Plasminógeno de Tipo Uroquinasa/metabolismoRESUMEN
Renal fibrosis is the final common pathway of a wide variety of chronic kidney diseases. Myofibroblast formation via the differentiation of from tissue-resident fibroblasts and bone marrow-derived mesenchymal stem cells (MSCs), and epithelial-to-mesenchymal transition (EMT) is known to play a pivotal role in the development of renal fibrosis. However, the detailed mechanisms underlying this disorder remain unclear. We herein investigated the role of alpha 2-antiplasmin (α2AP) in myofibroblast formation and the development of renal fibrosis. We observed the development of renal fibrosis using unilateral ureteral obstruction (UUO). α2AP had accumulated in the UUO-induced obstructed kidneys and α2AP deficiency attenuated UUO-induced renal fibrosis in mice. The degree of myofibroblast formation in the obstructed kidneys of α2AP(-/-) mice was less than that in α2AP(+/+) mice. In vitro, α2AP induced myofibroblast formation in renal tubular epithelial cells (RTECs), renal fibrosblasts, and bone marrow-derived mesenchymal stem cells (MSCs). α2AP also induced the production of TGF-ß, which is known to be a key regulator of myofibroblast formation and fibrosis. α2AP-induced the TGF-ß production was significantly reduced by SP600125, c-Jun N-terminal kinase (JNK) specific inhibitor. Our findings suggest that α2AP induces myofibroblast formation in the obstructed kidneys, and mediates the development of renal fibrosis.
Asunto(s)
Riñón/metabolismo , Miofibroblastos/metabolismo , Insuficiencia Renal/genética , Factor de Crecimiento Transformador beta/genética , Obstrucción Ureteral/genética , alfa 2-Antiplasmina/genética , Animales , Antracenos/farmacología , Diferenciación Celular , Células Epiteliales/metabolismo , Células Epiteliales/patología , Fibrosis , Regulación de la Expresión Génica , Riñón/patología , MAP Quinasa Quinasa 4/antagonistas & inhibidores , MAP Quinasa Quinasa 4/genética , MAP Quinasa Quinasa 4/metabolismo , Masculino , Células Madre Mesenquimatosas/metabolismo , Células Madre Mesenquimatosas/patología , Ratones , Ratones Noqueados , Miofibroblastos/patología , Cultivo Primario de Células , Inhibidores de Proteínas Quinasas/farmacología , Insuficiencia Renal/complicaciones , Insuficiencia Renal/metabolismo , Insuficiencia Renal/patología , Transducción de Señal , Factor de Crecimiento Transformador beta/metabolismo , Uréter/metabolismo , Uréter/patología , Obstrucción Ureteral/complicaciones , Obstrucción Ureteral/metabolismo , Obstrucción Ureteral/patología , alfa 2-Antiplasmina/deficienciaRESUMEN
BACKGROUND: The α2-antiplasmin (α2AP) protein is known to be a principal physiological inhibitor of plasmin, and is expressed in various part of the brain, including the hippocampus, cortex, hypothalamus and cerebellum, thus suggesting a potential role for α2AP in brain functions. However, the involvement of α2AP in brain functions is currently unclear. OBJECTIVES: The goal of this study was to investigate the effects of the deletion of the α2AP gene on the behavior of mice. METHODS: The motor function was examined by the wire hang test and rotarod test. To evaluate the cognitive function, a repeated rotarod test, Y-maze test, Morris water maze test, passive or shuttle avoidance test and fear conditioning test were performed. An open field test, dark/light transition test or tail suspension test was performed to determine the involvement of α2AP in anxiety or depression-like behavior. RESULTS AND CONCLUSIONS: The α2AP knockout (α2AP-/-) mice exhibited impaired motor function compared with α2AP+/+ mice. The α2AP-/- mice also exhibited impairments in motor learning, working memory, spatial memory and fear conditioning memory. Furthermore, the deletion of α2AP induced anxiety-like behavior, and caused an anti-depression-like effect in tail suspension. Therefore, our findings suggest that α2AP is a crucial mediator of motor function, cognitive function, anxiety-like behavior and depression-like behavior, providing new insights into the role of α2AP in the brain functions.