Deep Sequencing Analysis of the MicroRNAs in the Serum of Chronic Hepatitis B with Persistently Normal Alanine Aminotransferase

Background: Circulating miRNAs, a new family of miRNAs presentin plasma and serum, have shown great potential as novel body fluid biomarkers for non-invasive diagnosis and prognosis of several diseases. Methods: In the present study, we employed next-generation sequencing technology to analyze the expression profiles of circulating miRNAs in the serum of chronic hepatitis B (CHB) patients presenting persistently normal alanine aminotransferase with significant histological features (SPNALT),PNALT patients with no significant histological features (NSPNALT),and healthy control patients. Results: MiRNAs were found to be the major constituents of small RNA-annotated reads by comparing the annotate draw sequence reads with miRNA databases and genome and other small RNA libraries. Our results point to a total of 2767 unique reads that can be mapped to human miRNAs or pre-miRNAs in miRbase, and the pre-miRNAs can be further mapped to the human genome. Thirty novel miRNA genes were identified in three groups. The differential expression levels of 143 miRNAs showed significant variation when the SPNALT and control group were compared. Among these, 22 miRNAs were >4-fold up-regulated (P<0.01) in SPNALT group and 4 were >2-fold down-regulated (P<0.01).When the SPNALT and NSPNALT group were compared, the differential expression levels of 84 miRNAs showed significant variation. Among these, 13 miRNAs showed a >4-fold up-regulation (P<0.01) in the SPNALT group and 21 showed a >2-fold down-regulation (P<0.01). Conclusions: Our results show that circulating miRNAs in the serum of SPNALT patients could be more comprehensively detected by the next-generation sequencing technology. Newly identified miRNAs might be used as biomarkers for diagnosis of chronic hepatitis B patients presenting persistently normal alanine aminotransferase with significant histological features. Overall design: Serum samples were pooled from 6 healthy control donors (control group), 6 NSPNALT patients (NSPNALT group),and 6 SPNALT patients (SPNALT group). Sample sets were obtained fromThe First Affiliated Hospital of Soochow University.