title: Astragalus polysaccharide suppresses palmitate-induced apoptosis in human cardiac myocytes: the role of Nrf1 and antioxidant response.
abstract: OBJECTIVE
  Previous studies have shown that Astragalus polysaccharides (APS) can be used to ameliorate cardiotoxicity due to chemotherapy and improve the cardiac function. However, the mechanism by which APS mediate this effect is unclear. In the present study, the effects of APS, which suppressed ROS-mediated apoptosis through Nrf1 accumulation in human cardiac myocytes (HCMs), was investigated.
  
  
  METHODS
  The cell viability was detected by the CCK8 assay. The cell apoptosis was assessed by annexin V-PI double-labeling staining. Expression of genes and proteins were analyzed by real-time PCR and western blotting respectively. Nrf1 gene was overexpressed using a lentiviral expression vector in HCMs in vitro, in order to explore the mechanism by which the Nrf1 promoted cell growth.
  
  
  RESULTS
  CCK8 and Annexin V-PI double-labeling showed that PAL induced cell death in a concentration-dependent manner, and suppressed HCMs proliferation. The combination PAL with APS was significantly decreased the percentage of the early phase of apoptosis cells. ROS levels were increased in HCMs by exposure to PAL. APS treatment significantly inhibited generation of ROS in response to palmitate. Moreover, PAL administration significantly decreased the mRNA and proteins expression of Bcl-2 as well as increased the mRNA expression of BAX and the protein expression of caspase-3 and caspase-8 as compare to those of control group, but APS treatment could reverse PA-induced HCMs apoptosis. The levels of reactive oxygen species (ROS), which was an oxidative stress marker, was significantly increased in cardiomyocytes by exposure to PAL, but overexpressing Nrf1 could ameliorate ROS-induced cardiomyocyte toxicity and increase the expression of SOD1 and SOD2 in HCMs by overexpressing Nrf1.
  
  
  CONCLUSIONS
  This study demonstrated that the PAL could induce HCMs apoptosis. However, APS could reverse PAL-induced cardiomyocyte toxicity, at least partially, through suppression ROS and Nrf1 accumulation in HCMs.
authors.affiliation: Department of Cardiology, Shanghai Tenth People's Hospital of Tongji University Shanghai 200072, China.
authors.forename: Ji
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, Tongji Hospital of Tongji University Shanghai 200072, China.
authors.forename: Jian-Yun
authors.initials: JY
authors.lastname: Gu
authors.affiliation: Department of Cardiology, Tongji Hospital of Tongji University Shanghai 200072, China.
authors.forename: Zhi-Song
authors.initials: ZS
authors.lastname: Chen
authors.affiliation: Shanghai Cinoasia Institute Shanghai 200433, China.
authors.forename: Kai-Chen
authors.initials: KC
authors.lastname: Xing
authors.affiliation: Department of Cardiology, Tongji Hospital of Tongji University Shanghai 200072, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Sun
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D027883:Astragalus Plant; D015153:Blotting, Western; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D032383:Myocytes, Cardiac / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D051266:Nuclear Respiratory Factor 1 / Q000378:metabolism*; D010168:Palmitates / Q000633:toxicity; D018517:Plant Roots; D011134:Polysaccharides / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D059467:Transcriptome; D014162:Transfection
chemical_list: D004365:Drugs, Chinese Herbal; C495633:NRF1 protein, human; D051266:Nuclear Respiratory Factor 1; D010168:Palmitates; D011134:Polysaccharides; D017382:Reactive Oxygen Species
keywords: APS; HCMs; Palmitate; ROS; nuclear respiratory factor 1