Cordycepin ameliorates cardiac hypertrophy via activating the AMPKα pathway

Abstract

Increase of myocardial oxidative stress is closely related to the occurrence and development of cardiac hypertrophy. Cordycepin, also known as 3'-deoxyadenosine, is a natural bioactive substance extracted from Cordyceps militaris (which is widely cultivated for commercial use in functional foods and medicine). Since cordycepin suppresses oxidative stress both in vitro and in vivo, we hypothesized that cordycepin would inhibit cardiac hypertrophy by blocking oxidative stress-dependent related signalling. In our study, a mouse model of cardiac hypertrophy was induced by aortic banding (AB) surgery. Mice were intraperitoneally injected with cordycepin (20 mg/kg/d) or the same volume of vehicle 3 days after-surgery for 4 weeks. Our data demonstrated that cordycepin prevented cardiac hypertrophy induced by AB, as assessed by haemodynamic parameters analysis and echocardiographic, histological and molecular analyses. Oxidative stress was estimated by detecting superoxide generation, superoxide dismutase (SOD) activity and malondialdehyde levels, and by detecting the protein levels of gp91^phox and SOD. Mechanistically, we found that cordycepin activated activated protein kinase α (AMPKα) signalling and attenuated oxidative stress both in vivo in cordycepin-treated mice and in vitro in cordycepin treated cardiomyocytes. Taken together, the results suggest that cordycepin protects against post-AB cardiac hypertrophy through activation of the AMPKα pathway, which subsequently attenuates oxidative stress.

Keywords: AMPKα; cardiac hypertrophy; cardiac remodeling; cordycepin; oxidative stress.

Figure 1

Cordycepin attenuated cardiac hypertrophy induced by pressure‐overload in vivo. (A,B) HE staining of tissues from sham and AB model mice at 4 wk after surgery. The mice were treated with vehicle or cordycepin (n = 6). A: 10×; B: 400×. (C) Statistical results for the cross‐sectional area (n = 6 sample, 150‐200 cells per sample). (D‐E) Statistical results for the HW/BW ratio and HW/TL ratio at 4 wk after AB surgery (n = 10). (F‐H) mRNA levels of hypertrophic markers (n = 6). (I) Echocardiographic representative pictures. ^# P < 0.05 vs the sham group; *P < 0.05 vs the AB + vehicle group

Figure 2

Cordycepin attenuated cardiac fibrosis induced by pressure‐overload in vivo. (A‐C) Representative picrosirius red staining of histological sections and the statistical results (n = 6). (C‐F) Real‐time PCR analysis of fibrosis‐related genes (n = 6). (G,H) Representative blots of TGF‐β1, phosphorylated Smad2, total Smad2, phosphorylated Smad3 and total Smad3 from the indicated groups (n = 5). ^# P < 0.05 vs the sham group; *P < 0.05 vs the AB + vehicle group.

Figure 3

Cordycepin attenuated oxidative stress induced by pressure‐overload in vivo. (A,B) Detection of superoxide anion production rate and malondialdehyde (MDA) generation with related kits. (C‐F) Representative blots of gp91^phox, SOD1 and SOD2 from indicated groups (n = 5). (G,H) Detection of SOD activity and glutathione peroxidase (GSH‐Px) by related kits. ^# P < 0.05 vs the sham group; *P < 0.05 vs the AB + vehicle group

Figure 4

Effects of cordycepin on the AMPKα, ACC, mTOR and ERK1/2 signalling pathway. (A‐E) Protein levels of phosphorylated AMPKα and related targets in the indicated groups (n = 5). ^# P < 0.05 vs the sham group; *P < 0.05 vs the AB + vehicle group

Figure 5

The effects of cordycepin on hypertrophy induced by Ang II were blocked by Compound C (CpC). (A,B) Immunofluorescence staining of a‐actinin and the cell surface area of NRVMs in the indicated groups (n = 6 samples, with 150+ cells per group). (C‐E) The mRNA levels of ANP, BNP, and b‐MHC in NRVMs in each group (n = 6). ^# P < 0.05 vs the control group; *P < 0.05 vs the Ang II group.

Figure 6

The effects of cordycepin on AMPKα and pro‐hypertrophic pathways were blocked by Compound C (CpC). (A‐E) The protein levels of phosphorylated AMPKα and related targets in indicated groups (n = 6). *P < 0.05 vs the corresponding group

Figure 7

The effects of cordycepin on oxidative stress were blocked by Compound C (CpC) and a mechanistic simulation diagram. (A‐D) The protein levels of gp91^phox, SOD1, SOD2 in the indicated groups (n = 6). *P < 0.05 vs the corresponding group