Long Noncoding RNA AROD Inhibits Host Antiviral Innate Immunity via the miR-324-5p-CUEDC2 Axis.

Long noncoding RNAs (lncRNAs) are a class of noncoding RNAs that are involved in multiple biological processes. Here, we report a mechanism through which the lnc-AROD-miR-324-5p-CUEDC2 axis regulates the host innate immune response, using influenza A virus (IAV) as a model. We identified that host lnc-AROD without protein-coding capability is composed of 975 nucleotides. Moreover, lnc-AROD inhibited interferon-ß expression, as well as interferon-stimulated genes ISG15 and MxA. Furthermore, in vivo assays confirmed that lnc-AROD overexpression increased flu virus pathogenicity and mortality in mice. Mechanistically, lnc-AROD interacted with miR-324-5p, leading to decreased binding of miR-324-5p to CUEDC2. Collectively, our findings demonstrated that lnc-AROD is a critical regulator of the host antiviral response via the miR-324-5p-CUEDC2 axis, and lnc-AROD functions as competing endogenous RNA. Our results also provided evidence that lnc-AROD serves as an inhibitor of the antiviral immune response and may represent a potential drug target. IMPORTANCE lnc-AROD is a potential diagnostic and discriminative biomarker for different cancers. However, so far the mechanisms of lnc-AROD regulating virus replication are not well understood. In this study, we identified that lnc-AROD is downregulated during RNA virus infection. We demonstrated that lnc-AROD enhanced CUEDC2 expression, which in turn inhibited innate immunity and favored IAV replication. Our studies indicated that lnc-AROD functions as a competing endogenous RNA that binds miR-324-5p and reduces its inhibitory effect on CUEDC2. Taken together, our findings reveal that lnc-AROD plays an important role during the host antiviral immune response.

Optimized Expression, Purification of Herpes B Virus gD Protein in Escherichia coli, and Production of Its Monoclonal Antibodies.

BACKGROUND: Herpes B virus (BV) is a zoonotic disease caused by double-stranded enveloped DNA virus with cercopithecidae as its natural host. The mortality rate of infected people could be up to 70% with fatal encephalitis and encephalomyelitis. Up to now, there are no effective treatments for BV infection. Among the various proteins encoded by monkey B virus, gD, a conserved structural protein, harbors important application value for serological diagnosis of frequent variations of the monkey B virus. OBJECTIVES: This study aimed to expressed the gD protein of BV in Escherichia coli by a recombinant vector, and prepare specific monoclonal antibodies against gD of BV to pave the way for effective and quick diagnosis reagent research. MATERIALS AND METHODS: The gD gene of BV was optimized by OptimWiz to improve codon usage bias and synthesis, and the recombinant plasmid, pET32a/gD, was constructed and expressed in E. coli Rosetta (DE3). The expressed fusion protein, His-gD, was purified and the BALB/c mice were immunized by this protein. Spleen cells from the immunized mice and SP2/0 myeloma cells were fused together, and the monoclonal cell strains were obtained by indirect enzyme-linked immunosorbent assay (ELISA) screening, followed by preparation of monoclonal antibody ascetic fluid. RESULTS: The optimized gD protein was highly expressed in E. coli and successfully purified. Five monoclonal antibodies (mAbs) against BV were obtained and named as 4E3, 3F8, 3E7, 1H3 and 4B6, and with ascetic fluid titers of 2 × 10(6), 2 × 10(5), 2 × 10(5), 2 × 10(3) and 2 × 10(2), respectively. The 1H3 and 4E3 belonged to the IgG2b subclass, while 3E7, 3F8 and 4B6 belonged to the IgG1 subclass. CONCLUSIONS: The cell lines obtained in this work secreted potent, stable and specific anti-BV mAbs, which were suitable for the development of herpes B virus diagnosis reagents.

Prokaryotic Expression, Purification, and Polyclonal Antibody Production of a Truncated Recombinant Rabies Virus L Protein.

BACKGROUND: Rabies virus (RABV) is a deadly neurotropic virus that causes the disease of rabies in humans and animals. L protein is one of the large structural protein of rabies virus, which displays multiple enzymatic activities, and is required for viral transcription and replication. OBJECTIVES: A truncated L protein of Rabies virus is being cloned, expressed and purified to produce relevant polyclonal antibody. MATERIALS AND METHODS: The gene fragment of L protein of RABV was subcloned into prokaryotic expression vector pET- 28a and transformed into E. coli Rosetta DE3 host strain. The recombinant L protein of RABV was expressed and characterized by SDS-PAGE and western blot analysis using anti-his tag antibody. Mice were immunized with the purified recombinant L protein, the reaction of the anti-serum was checked by immunofluorescence and dot-blot, respectively. RESULTS: The results of PCR and sequencing confirmed that the fragment of L gene of RABV was successfully cloned into the expression vector. The expression of recombinant L protein fragment induced by IPTG was confirmed by the band of 43 kDa in SDS-PAGE and western blot. The antiserum of purified L protein immunized mice was reacted with RABV infected N2a cells and suckling mouse brain tissue lysates. CONCLUSIONS: Our data showed that the recombinant L protein produced by pET-28a vector was very successful, and the purified L protein could efficiently induce the antibody response in mice. The antiserum could recognize the virus in RABV infected cells and tissue very well.