MicroRNAs may solve the mystery of chronic hepatitis B virus infection.

Hepatitis B virus (HBV) infection is a global public health problem that causes persistent liver diseases such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma. A large amount of people die annually from HBV infection. However, the pathogenesises of the HBV-related diseases are ill defined and the therapeutic strategies for the diseases are less than optimum. The recently discovered microRNAs (miRNAs) are tiny noncoding RNAs that regulate gene expression primarily at the post-transcriptional level by binding to mRNAs. miRNAs contribute to a variety of physiological and pathological processes. A number of miRNAs have been found to play a pivotal role in the host-virus interaction including host-HBV interaction. Numerous studies have indicated that HBV infection could change the cellular miRNA expression patterns and different stages of HBV associated disease have displayed distinctive miRNA profiles. Furthermore, the differential expressed miRNAs have been found involved in the progression of HBV-related diseases, for instance some miRNAs are involved in liver tumorigenesis and tumor metastasis. Studies have also shown that the circulating miRNA in serum or plasma might be a very useful biomarker for the diagnosis and prognosis of HBV-related diseases. In addition, miRNA-based therapy strategies have attracted increasing attention, indicating a promising future in the treatment of HBV-related diseases.