Signal transducer and activator of transcription 4 (STAT4) is a member of the STAT family and localizes to the cytoplasm. STAT4 is phosphorylated after a variety of cytokines bind to the membrane, and then dimerized STAT4 translocates to the nucleus to regulate gene expression. We reviewed the essential role played by STAT4 in a wide variety of cells and the pathogenesis of diverse human diseases, especially many kinds of autoimmune and inflammatory diseases, via activation by different cytokines through the Janus kinase (JAK)-STAT signaling pathway.

Hepatocellular carcinoma (HCC) is one of the most notable lethal malignancies worldwide. However, the molecular mechanisms involved in the initiation and progression of this disease remain poorly understood. Over the past decade, many studies have demonstrated the important regulatory roles of long non-coding RNAs (lncRNAs) in HCC. Here, we comprehensively review recent discoveries regarding HCC-associated lncRNA functions, which we have classified and described according to their mechanism models. Electronic supplementary material The online version of this article (10.1186/s13046-019-1213-0) contains supplementary material, which is available to authorized users.

Summary Background Hepatitis B virus (HBV) infection is a serious global health burden. TRIM26 has been reported to affect hepatitis C virus replication. Aims To manifest the role of TRIM26 on HBV replication and explore if there are single‐nucleotide polymorphisms (SNPs) in TRIM26 associated with response to pegylated interferon‐alpha (PegIFNα) treatment in patients with chronic hepatitis B (CHB). Methods We investigated the effect and mechanism of TRIM26 on HBV replication in vitro. The association between SNPs in TRIM26 and PegIFNα treatment response was evaluated in two independent cohorts including 238 and 707 patients with HBeAg‐positive CHB. Results Knockdown of TRIM26 increased, while overexpression of TRIM26 inhibited, HBV replication. Co‐immunoprecipitation assays and immunofluorescence showed that TRIM26 interacted and co‐localised with HBx. Co‐transfection of HBx‐HIS and TRIM26‐FLAG plasmids in Huh7 cells showed that TRIM26 inhibited the expression of HBx. Furthermore, TRIM26 inhibited HBV replication by mediating HBx ubiquitination degradation, and TRIM26 SPRY domain was responsible for the interaction and degradation of HBx. Besides, IFN increased TRIM26 expression. TRIM26 rs116806878 was associated with response to PegIFNα in two CHB cohorts. Moreover, a polygenic score integrating TRIM26 rs116806878, STAT4 rs7574865 and CFB rs12614 (previously reported to be associated with response to PegIFNα) was related to response to PegIFNα in CHB. Conclusions TRIM26 inhibits HBV replication; IFN promotes TRIM26 expression. TRIM26 exerts an inhibitory effect on HBx by promoting ubiquitin‐mediated degradation of HBx. Furthermore, TRIM26 rs116806878 is a potential predictive biomarker of response to PegIFNα in patients with CHB.