Adiponectin protects against doxorubicin-induced cardiomyopathy by anti-apoptotic effects through AMPK up-regulation

Department of Cardiovascular Medicine, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
Cardiovascular Research (Impact Factor: 5.94). 10/2010; 89(2):309-19. DOI: 10.1093/cvr/cvq335
Source: PubMed


Adiponectin (APN) has been reported to protect against ischaemia-reperfusion injury and hypertrophy. However, few reports have investigated the cardioprotective effects of APN in doxorubicin (DOX)-induced cardiomyopathy; therefore, we studied the cardioprotective mechanisms of APN in this model.
In an in vivo study, we quantified the cardiac pathohistology of C57BL/6 mice [wild-type (WT) mice], APN transgenic mice with high APN concentrations [APN transgenic sense (SE) mice], and those with reduced APN concentrations [APN transgenic antisense (AS) mice] after intraperitoneal injections of DOX (4 mg/kg) weekly for 6 weeks. The survival rate after 14 days was significantly increased in APN-SE mice (WT vs. APN-AS vs. APN-SE: 40 vs. 17 vs. 73%, P < 0.05). We assessed myocardial pathohistological changes and observed that fibrosis and apoptosis were significantly decreased in APN-SE mice compared with those of the other groups. We also assessed DOX-induced apoptotic mechanisms in vitro using cultured cardiomyocytes isolated from neonatal WT mice. The expression of adenosine monophosphate-activated protein kinase (AMPK) and anti-apoptotic factor Bcl-2 increased, but that of pro-apoptotic factor Bax decreased in cardiomyocytes treated with highly concentrated APN. The protective effects of APN were reversed by the addition of an AMPK inhibitor (dorsomorphin) to the culture medium.
These data suggest that APN improved cardiac function through anti-apoptotic effects by up-regulation of AMPK in DOX-induced cardiomyopathy in mice.

  • Source
    • "However, some researchers reported that DOX inhibited AMPKα phosphorylation in cardiomyocytes [33], [34], In these studies, AMPK phosphorylation was detected at 24 h and 16 h after DOX stimulation, whereas AMPK and p53 phosphorylation were examined at 2 h after DOX exposure in our study. In fact, they also observed that DOX activated AMPK at the initial stage (<4 h) [34]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Cardiomyocyte apoptosis is an important event in doxorubicin (DOX)-induced cardiac injury. The aim of the present study was to investigate the protection of berberine (Ber) against DOX- triggered cardiomyocyte apoptosis in neonatal rat cardiomyocytes and rats. In neonatal rat cardiomyocytes, Ber attenuated DOX-induced cellular injury and apoptosis in a dose-dependent manner. However, Ber has no significant effect on viability of MCF-7 breast cancer cells treated with DOX. Ber reduced caspase-3 and caspase-9, but not caspase-8 activity in DOX-treated cardiomyocytes. Furthermore, Ber decreased adenosine monophosphate-activated protein kinase α (AMPKα) and p53 phosphorylation at 2 h, cytosolic cytochrome c and mitochondrial Bax levels and increased Bcl-2 level at 6 h in DOX-stimulated cardiomyocytes. Pretreatment with compound C, an AMPK inhibitor, also suppressed p53 phosphorylation and apoptosis in DOX-treated cardiomyocytes. DOX stimulation for 30 min led to a loss of mitochondrial membrane potential and a rise in the AMP/ATP ratio. Ber markedly reduced DOX-induced mitochondrial membrane potential loss and an increase in the AMP/ATP ratio at 1 h and 2 h post DOX exposure. In in vivo experiments, Ber significantly improved survival, increased stroke volume and attenuated myocardial injury in DOX-challenged rats. TUNEL and Western blot assays showed that Ber not only decreased myocardial apoptosis, caspase-3 activation, AMPKα and p53 phosphorylation, but also increased Bcl-2 expression in myocardium of rats exposed to DOX for 84 h. These findings indicate that Ber attenuates DOX-induced cardiomyocyte apoptosis via protecting mitochondria, inhibiting an increase in the AMP/ATP ratio and AMPKα phosphorylation as well as elevating Bcl-2 expression, which offer a novel mechanism responsible for protection of Ber against DOX-induced cardiomyopathy.
    Preview · Article · Oct 2012 · PLoS ONE
  • Source
    • "PI3K/Akt has been shown to play a major role in the prevention of apoptosis [16], and ERK1/2 is a well-known taking part in a signal transduction cascade in response to extracellular stimuli, and plays an important role in cell proliferation, growth and cell death [17]. Several studies have exhibited that anti-apoptotic effect of adiponectin on the heart, which appeared to be mediated via PI3K/Akt, ERK1/2MAPK and AMP-activated protein kinase (AMPK) signaling pathway [15,18,19]. Adiponectin could protect against acute cardiac injury by attenuating the apoptosis, but the mechanism involved the effect of adiponectin in palmitate-induced apoptosis are not fully understood. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Cardiomyocytes apoptosis is an important contributor to myocardial dysfunction and heart failure. Adiponectin has cardioprotective effects, potential mechanisms behind it are not clear in cardiomyocytes. The purpose of the study was to investigate whether adiponectin can block palmitate-induced apoptosis and the underlying biochemical mechanism in H9c2 cells. Methods H9c2 cells were treated with palmitate presence or absence of 2.5 μg/mL globular adiponectin. The effect on the cell viability of H9c2 cells was evaluated using MTT assay, and cell apoptosis was determined by Hoechst 33342 staining. Protein expression was measured using the western blot method. Results Our results showed that the palmitate treatment induced apoptosis in H9c2 cells, which was associated with increasing the level of cleaved caspase-3 and cleaved PARP. Meanwhile, palmitate-induced apoptosis increased the protein level of p-ERK1/2, and decreased the protein level of p-Akt significantly. However, levels of both of these proteins were restored to the normal when pretreated with adiponectin, and followed with the decrease of cleaved caspase-3 and cleaved PARP. In line with these results, the protective effect of adiponectin can be blocked by PI3K/Akt inhibitor LY294002, and palmitate-induced apoptosis can be attenuated by ERK1/2 inhibitor U0126. Conclusions Taken together, the present study demonstrated that adiponectin protects H9c2 cells from palmitate-induced apoptosis via PI3K/Akt and ERK1/2 signaling pathways. Our results reveal a link between adiponectin and cardiomyocytes apoptosis, suggesting that adioponectin may be a promising therapeutic for the treatment of lipotoxicity cardiomyopathy.
    Full-text · Article · Oct 2012 · Lipids in Health and Disease
    • "Adiponectin is an adipokine synthesized in the adipose tissue, which, through its binding to specific receptors and the activation of AMPK, exerts beneficial effects on the vasculature and myocardium [21]. The expression of adiponectin and its receptors has been described in the myocardium [22] [23], along with its capacity to reduce oxidative stress and to promote cell survival [21] and even to attenuate the apoptosis induced by doxorubicin [24]. However, it is not known whether metformin Free Radical Biology & Medicine 51 (2011) 1861–1871 Abbreviations: adipoR, adiponectin receptor; AMPK, 5′-adenosine monophosphateactivated protein kinase; CAT, catalase; GPx, glutathione peroxidase; ROS, reactive oxygen species; SOD, superoxide dismutase; siRNA, small interfering RNA. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Doxorubicin has cardiotoxic effects that limit its clinical benefit in cancer patients. Metformin exerts cardioprotective actions via AMP-activated protein kinase (AMPK) and increases the expression of adiponectin and its receptors (adipoR1 and adipoR2) in skeletal muscle and adipose tissue, but its effect on cardiac tissue is still unknown. This work aimed to study whether metformin exerts any protective action against the cardiotoxicity of doxorubicin and whether the cardiac system of adiponectin is involved in any such action. The addition of doxorubicin (5μM) to adult mouse cardiomyocytes (HL-1 cell line) induced apoptosis, which was characterized by a loss of cell viability, activation of caspases, and fragmentation of the genetic material. Doxorubicin treatment also caused a decrease in the activity of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase. Pretreatment with metformin (4mM, 24h) provided protection against doxorubicin-induced damage. This pretreatment significantly increased cell viability, attenuated the activation of caspases and the fragmentation of genetic material, and restored the antioxidant activity. In addition, metformin up-regulated the expression of adiponectin and its receptors, adipoR1 and adipoR2, in cardiomyocytes. In contrast, silencing either adipoR1 or adipoR2 with siRNA inhibited the AMPK activation and the protective effects of metformin. Taken together, these results demonstrate that metformin protects cardiomyocytes from doxorubicin-induced damage and that the cardiac adiponectin system plays an important role in this protective action.
    No preview · Article · Aug 2011 · Free Radical Biology and Medicine
Show more