Effect of HCV NS3 on proliferation and phosphorylation of MAPK in human hepatocytes

Gene expression profile analysis of spontaneous reversion of CCl4-induced hepatic fibrosis in rats

AIM: To screen the differentially expressed gene in the spontaneous reversion of hepatic fibrosis induced by carbon tetrachloride (CCl₄), and to reveal the gene expression profile in this process.

METHODS: Animal model of hepatic fibrosis with spontaneous reversion was created in SD rats by injection of carbon tetrachloride (CCl₄) for 8 weeks and then withdrawing for 6 weeks. The mRNA of liver tissues was extracted at different time spots in the process of reversion. Then cDNA microarray was used to screen the differentially expressed genes. Finally the products were subjected to hierarchical clustering and confirmed by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) of α-synuclein, A-raf, presenilin-2 and β-actin.

RESULTS: Hepatic fibrosis was progressively reversed after stopping injection of CCl₄. All together, there were 254 (21.59%) genes that changed at the transcription level. Meanwhile, 54, 85, 97 and 132 genes were identified differentially expressed in the 8^th, 10^th, 12^th and 14^th week, respectively. After confirmed by RT-PCR, the differentially expressed were associated with metabolic enzymes, ion channels, transcription factors, gastrointestinal hormones and their receptors, mitogen-activated protein kinase (MAPK) and PI3k/Akt signaling pathway.

CONCLUSION: The gene expression profile is significantly changed in the spontaneous recovery of CCl₄-induced hepatic fibrosis. Genes closely related to the spontaneous recovery are associated with metabolic enzymes, transporter/symporter proteins, gastrointestinal hormones/receptors, lipoprotein/fatty acid binding proteins, transcription factor/nuclear factors, and MAPK signal pathway.

RNA interference: Antiviral weapon and beyond

RNA interference (RNAi) is a remarkable type of gene regulation based on sequence-specific targeting and degradation of RNA. The term encompasses related pathways found in a broad range of eukaryotic organisms, including fungi, plants, and animals. RNA interference is part of a sophisticated network of interconnected pathways for cellular defense, RNA surveillance, and development and it may become a powerful tool to manipulate gene expression experimentally. RNAi technology is currently being evaluated not only as an extremely powerful instrument for functional genomic analyses, but also as a potentially useful method to develop specific dsRNA based gene-silencing therapeutics. Several laboratories have been interested in using RNAi to control viral infection and many reports in Nature and in Cell show that short interfering (si) RNAs can inhibit infection by HIV-1, polio and hepatitis C viruses in a sequence-specific manner. RNA-based strategies for gene inhibition in mammalian cells have recently been described, which offer the promise of antiviral therapy.