title: Long non-coding RNAs expression profile in HepG2 cells reveals the potential role of long non-coding RNAs in the cholesterol metabolism.
abstract: BACKGROUND
  Green tea has been shown to improve cholesterol metabolism in animal studies, but the molecular mechanisms underlying this function have not been fully understood. Long non-coding RNAs (lncRNAs) have recently emerged as a major class of regulatory molecules involved in a broad range of biological processes and complex diseases. Our aim was to identify important lncRNAs that might play an important role in contributing to the benefits of epigallocatechin-3-gallate (EGCG) on cholesterol metabolism.
  
  
  METHODS
  Microarrays was used to reveal the lncRNA and mRNA profiles in green tea polyphenol(-)-epigallocatechin gallate in cultured human liver (HepG2) hepatocytes treated with EGCG and bioinformatic analyses of the predicted target genes were performed to identify lncRNA-mRNA targeting relationships. RNA interference was used to investigate the role of lncRNAs in cholesterol metabolism.
  
  
  RESULTS
  The expression levels of 15 genes related to cholesterol metabolism and 285 lncRNAs were changed by EGCG treatment. Bioinformatic analysis found five matched lncRNA-mRNA pairs for five differentially expressed lncRNAs and four differentially expressed mRNA. In particular, the lncRNA AT102202 and its potential targets mRNA-3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) were identified. Using a real-time polymerase chain reaction technique, we confirmed that EGCG down-regulated mRNA expression level of the HMGCR and up-regulated expression of AT102202. After AT102202 knockdown in HepG2, we observed that the level of HMGCR expression was significantly increased relative to the scrambled small interfering RNA control (P < 0.05).
  
  
  CONCLUSIONS
  Our results indicated that EGCG improved cholesterol metabolism and meanwhile changed the lncRNAs expression profile in HepG2 cells. LncRNAs may play an important role in the cholesterol metabolism.
authors.forename: Gang
authors.initials: G
authors.lastname: Liu
authors.forename: Xinxin
authors.initials: X
authors.lastname: Zheng
authors.forename: Yanlu
authors.initials: Y
authors.lastname: Xu
authors.forename: Jie
authors.initials: J
authors.lastname: Lu
authors.forename: Jingzhou
authors.initials: J
authors.lastname: Chen
authors.affiliation: Department of Special Medical Treatment Center, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Huang
mesh_terms: D002392:Catechin / Q000031:analogs & derivatives / Q000378:metabolism; D045744:Cell Line, Tumor; D002784:Cholesterol / Q000378:metabolism*; D056945:Hep G2 Cells; D006801:Humans; D062085:RNA, Long Noncoding / Q000235:genetics*
chemical_list: D062085:RNA, Long Noncoding; D002392:Catechin; D002784:Cholesterol; C045651:epigallocatechin gallate