Proliferative effect of hypericine on human skin fibroblast cells and identification of the mechanism of action in molecular level

Abstract

Hypericine is traditionally used as a wound healing agent. There-fore it is a potential promoter for reprogramming inducedpluripotent stem cells (IPSCs) which posses several problems due to drawbacks associated with efficiency and viral genome integra-tion. In order to improve reprogramming efficiency and compen-sate for viral transduction, new chemicals have been exploredthrough IPSC research. The aim of this study was to investigatethe proliferative effect of hypericine on human skin fibroblastcells (SF) in-vitro, and to identify the mechanism of action inmolecular level.The proliferation was measured using the Clonogenic andDimethylthiazol Diphenyltetrazolium Bromide (MTT) assays.Real-time quantitative polymerase chain reaction (qRT-PCR)was performed to detect the mRNA levels of cyclins (D1 and B1)and cell cycle controller genes (p53 and p21).SF cells were treated with different doses (1 nM–100lM) ofhypericine for 24 h and 48 h. A significant cell proliferation wasobserved in moderate concentrations (0.1–15lM; %110–%134),but at high concentrations (25–50lM) cytotoxic effects emergedin SF cells (IC50=23.62 M,R2=0.915). qRT-PCR resultsrevealed that the most proliferative dose of hypericine (15lM)stimulates cyclin D1. The anti-proliferative activity of hypericinewas accompanied by inhibition of cyclin B1 mRNA, whereas itinduced expression of p53 and p21 genes, and thus apoptosis wasobserved by DNA laddering at the same dose (50lM).Overall results suggested that hypericine can compensate forviral transduction and improve reprogramming efficiency ofIPSCs by enforcing them in G1 phase. Hence we report thathypericine can be a good candidate component for cocktails pro-duced to trigger IPSC proliferation.