Reversal effects of Isochlorogenic acid A on HBV-induced transcriptional dysregulation and apoptotic signaling

Abstract

Chronic hepatitis B virus (HBV) infection contributes to hepatocellular carcinoma by disrupting host transcription, cell-cycle control, and apoptotic signaling. Isochlorogenic acid A (ICAA), a natural compound with antiviral and hepatoprotective properties, was previously shown to inhibit HBV replication by interfering with multiple steps of the viral life cycle. Because chronic HBV often reflects an imbalance between proliferation and cell death, we investigated how ICAA affects gene expression related to these processes in the presence or absence of HBV. We performed transcriptome analysis using RNA sequencing (RNA-seq) in HepAD38 cells (a HepG2-derived stable HBV-expressing line) and HepG2 control cells (HBV-negative) treated with ICAA or DMSO. HBV caused major differences in gene expression in HepAD38 cells compared with HBV-negative HepG2 cells. Principal component analysis showed that ICAA significantly altered HBV-dependent expression patterns, resulting in 189 differentially expressed genes (DEGs) that were regulated in opposite directions by both HBV and ICAA. Functional enrichment analysis highlighted pathways in viral carcinogenesis, apoptosis, MAPK signaling, and p53 signaling. Annexin V/propidium iodide assays showed apoptotic cells in both treated and untreated HepAD38 cultures, with only minor pattern changes. Mechanistically, in untreated HBV-positive cells caspase-9 cleavage failed to activate PARP, suggesting that induction of intrinsic apoptosis is followed by blocked execution. In contrast, ICAA inhibits caspase-9 cleavage in a dose-dependent manner, while activating PARP. Consistent with this, ICAA treatment increased apoptotic DNA fragmentation in HepAD38, reflecting the proapoptotic potential of ICAA under these conditions facilitating the elimination of HBV-positive cells by apoptosis. These findings highlight the potential therapeutic relevance of this compound in processes associated with HBV pathogenesis, together with its antiviral effect. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=185 SRC="FIGDIR/small/733975v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@38d107org.highwire.dtl.DTLVardef@235a13org.highwire.dtl.DTLVardef@ee988aorg.highwire.dtl.DTLVardef@60cb13_HPS_FORMAT_FIGEXP M_FIG C_FIG