Résumé
The aims of the present study were to evaluate the effects of puerarin on angiotensin II-induced cardiac fibroblast proliferation and to explore the molecular mechanisms of action. Considering the role of HO in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation, we hypothesized that modulating catalase activity would be a potential target in regulating the redox-sensitive pathways. Our results showed that the activation of Rac1 was dependent on the levels of intracellular HO. Puerarin blocked the phosphorylation of extracellular regulated protein kinases (ERK)1/2, abolished activator protein (AP)-1 binding activity, and eventually attenuated cardiac fibroblast proliferation through the inhibition of HO-dependent Rac1 activation. Further studies revealed that angiotensin II treatment resulted in decreased catalase protein expression and enzyme activity, which was disrupted by puerarin via the upregulation of catalase protein expression at the transcriptional level and the prolonged protein degradation. These findings indicated that the anti-proliferation mechanism of puerarin was mainly through blocking angiontensin II-triggered downregulation of catalase expression and HO-dependent Rac1 activation.
Sujets)
Animaux , Souris , Angiotensine-II , Pharmacologie , Antagonistes du récepteur de type 1 de l'angiotensine-II , Pharmacologie , Animaux nouveau-nés , Catalase , Génétique , Métabolisme , Prolifération cellulaire , Cellules cultivées , Extracellular Signal-Regulated MAP Kinases , Métabolisme , Fibroblastes , Régulation de l'expression des gènes , Coeur , Peroxyde d'hydrogène , Métabolisme , Pharmacologie , Isoflavones , Pharmacologie , Myocarde , Biologie cellulaire , Métabolisme , NADPH oxidase , Métabolisme , Neuropeptides , Métabolisme , Transduction du signal , Facteur de transcription AP-1 , Métabolisme , Activation de la transcription , Protéine G rac1 , MétabolismeRésumé
The aims of the present study were to evaluate the effects of puerarin on angiotensin II-induced cardiac fibroblast proliferation and to explore the molecular mechanisms of action. Considering the role of HO in nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation, we hypothesized that modulating catalase activity would be a potential target in regulating the redox-sensitive pathways. Our results showed that the activation of Rac1 was dependent on the levels of intracellular HO. Puerarin blocked the phosphorylation of extracellular regulated protein kinases (ERK)1/2, abolished activator protein (AP)-1 binding activity, and eventually attenuated cardiac fibroblast proliferation through the inhibition of HO-dependent Rac1 activation. Further studies revealed that angiotensin II treatment resulted in decreased catalase protein expression and enzyme activity, which was disrupted by puerarin via the upregulation of catalase protein expression at the transcriptional level and the prolonged protein degradation. These findings indicated that the anti-proliferation mechanism of puerarin was mainly through blocking angiontensin II-triggered downregulation of catalase expression and HO-dependent Rac1 activation.