Gene expression profiling of sense and antisense transcripts in liver regeneration by microarray analysis

Abstract

Liver regeneration is a hyperplastic phenomenon induced by partial hepatectomy (PH) or hepatic damage. A large number of genes have been indicated to be involved in the process of liver regeneration. It was recently reported that natural antisense transcripts are involved in the regulation of gene expression. However, no antisense transcript expressions in liver regeneration have been reported thus far. Therefore, the present study aimed to comprehensively identify up- or downregulated sense and antisense transcripts in liver regeneration using PH mice and a sense/antisense custom-microarray. The results showed that 97 genes were upregulated and 7 genes were downregulated for sense transcripts, whereas 15 genes were upregulated and 2 genes were downregulated for antisense transcripts in regenerating livers as compared to normal livers (P<0.05 and fold change >2.0). Sense and antisense transcripts of the genes, Apoa4, Hp, Fgb and Fgg, exhibited concordant upregulation during the course of liver regeneration. Apoa4, Hp and Fgb transcripts were further investigated by strand-specific reverse transcription-quantitative polymerase chain reaction (RT-qPCR), revealing results consistent with those of the microarray. In conclusion, the up- or downregulated sense and antisense transcripts identified in the present study are suggested to be involved in liver regeneration.

Keywords: 70%; liver regeneration; microarray; partial hepatectomy; sense/antisense transcripts; strand-specific reverse transcription-quantitative polymerase chain reaction.

Figure 1

Histological appearance of regenerating livers at each time point post PH. Mice were sacrificed at five time points: 0, 2, 6, 12 and 24 h post PH. Regenerating livers were embedded in paraffin blocks. In order to visualize the fine structures of regenerating livers, hematoxylin and eosin staining was performed on the 4-μm sections. Scale bar, 50 mm.

Figure 2

Venn diagram of upregulated (Up) sense and antisense transcripts in liver regeneration based on microarray analysis.

Figure 3

Relative expression ratio of Apoa4, Hp and Fgb sense and antisense transcripts in the early phase of live regeneration. Total RNAs were isolated from regenerating and sham-operated livers (n=3 at each time point). Strand-specific cDNA derived from sense or antisense transcripts was synthesized using the reverse or forward primers described in Table III. qPCRs were performed using these primer pairs, Power SYBR-Green PCR Master Mix and StepOnePlus Real-Time PCR system. Means ± standard error of the mean (SEM) were obtained using the standard-curve method and calculated taking the values of strand-specific RT-qPCR at 0 h post PH (normal livers) as 1.0. (A) Apoa4 sense transcripts. (B) Apoa4 antisense transcripts. (C) Hp sense transcripts. (D) Hp antisense transcripts. (E) Fgb sense transcripts. (F) Fgb antisense transcripts.