Transcriptome Analysis Illuminates a Hub Role of SREBP2 in Cholesterol Metabolism by α-Mangostin

摘要

Whole-transcriptome analysis of α-mangostin-treated HepG2 cells revealed that genes relevant to lipid and cholesterol metabolic processes responded to α-mangostin treatment. α-Mangostin downregulated a series of cholesterol biosynthetic genes, including SQLE , HMGCR , and LSS , and controlled specific cholesterol trafficking-associated genes such as ABCA1 , SOAT1 , and PCSK9 . In particular, the downregulation of SREBP2 expression highlighted SREBP2 as a key transcriptional factor controlling lipid or cholesterol metabolic processes. Gene network analysis of SREBP2 and responses of its target proteins demonstrated that the effect of α-mangostin on HepG2 cells was mediated by the downregulation of SREBP2 expression, which was further supported by the reduction of the amount of SREBP2–SCAP complex. In the presence of exogenous cholesterols, α-mangostin downregulated SREBP2 expression and suppressed PCSK9 synthesis, which might contribute to the increased cholesterol uptake in cells, in part explaining the cholesterol-lowering effect of α-mangostin.