A phase 2, open-label, randomized, multiple-dose study evaluating Inarigivir in treatment-naïve patients with chronic hepatitis B

BACKGROUND/AIMS

Novel agents acting against hepatitis B virus (HBV) are needed to improve HBsAg seroclearance or termed as 'functional cure'. Inarigivir (retinoic acid-inducible gene I agonist) has immunomodulatory and direct antiviral actions against HBV. We aimed to determine the safety and efficacy of Inarigivir for the treatment of HBV infection.

PATIENTS/METHODS

80 treatment-naïve patients were randomized in 4 ascending dose cohorts to receive 12 weeks of Inarigivir 25, 50, 100, 200 mg or placebo in a ratio of 4:1. All patients were then given tenofovir for another 12 weeks.

RESULTS

Least squares (LS) mean reductions in HBV DNA from baseline increased with higher doses of Inarigivir (0.6116 in 25 mg and 1.5774 in 200 mg groups vs. 0.0352 in placebo group) (95% CI 0.9518-0.2011 and 1.921-1.1634 respectively). LS mean changes in HBV RNA and HBsAg from baseline ranged from -0.3856 to -0.5794 versus -0.1474 and -0.0956 to -0.1818 versus +0.0026 in Inarigivir-treated versus placebo groups respectively. During the tenofovir-treated period, LS mean reductions in HBsAg in the Inarigivir-treated groups ranged from 0.1709 to 0.3529 versus 0.1984 in the placebo group. Inarigivir-treated groups showed mean reductions in ALT from baseline between 23.3 and 33.8 versus 0.7 U/L in the placebo group. Treatment-emergent adverse events related to Inarigivir and placebo occurred in 4.7% and 6.3% patients respectively.

CONCLUSIONS

Twelve-week Inarigivir up to 200 mg dose was associated with a reduction of HBV DNA, HBV RNA and antigen levels. A trend for greater HBsAg reduction was observed in Inarigivir pre-treated patients after switching to tenofovir.

A Human Long Non-coding RNA LncATV Promotes Virus Replication Through Restricting RIG-I-Mediated Innate Immunity

Pattern recognition receptors sense pathogen components and initiate the host antiviral innate immune response, such as inducing interferons (IFNs). Long non-coding RNAs (lncRNAs) are emerging regulators of multiple biological processes. However, their role in antiviral response, especially through regulating the human innate immune, is largely unexplored. Here we characterized that lncATV, a human specific lncRNA, was up-regulated upon type I/III IFN stimulations and virus infection. LncATV was cytoplasmic localized and relatively high expressed in human monocytes, erythroleukemia cells and hepatoma cells. Notably, lncATV knockdown significantly inhibited the replication of multiple RNA viruses, such as hepatitis C virus, Zika virus, Newcastle disease virus, and Sendai virus. Mechanistically, RIG-I antiviral signaling and IFN effective pathway were enhanced when lncATV expression was knocked down but inhibited by overexpressed lncATV. RNA immunoprecipitation results demonstrated an association between LncATV and RIG-I. Collectively, our findings reveal the functional role of a novel human specific lncATV as a regulatory lncRNA restricting virus associated innate immune response.

What Really Rigs Up RIG-I?

RIG-I (retinoic acid-inducible gene 1) is an archetypal member of the cytoplasmic DEAD-box dsRNA helicase family (RIG-I-like receptors or RLRs), the members of which play essential roles in the innate immune response of the metazoan cell. RIG-I functions as a pattern recognition receptor that detects nonself RNA as a pathogen-associated molecular pattern (PAMP). However, the exact molecular nature of the viral RNAs that act as a RIG-I ligand has remained a mystery and a matter of debate. In this article, we offer a critical review of the actual viral RNAs that act as PAMPs to activate RIG-I, as seen from the perspective of a virologist, including a recent report that the viral Leader-read-through transcript is a novel and effective RIG-I ligand.

Increased expression of retinoic acid-induced gene 1 in the dorsolateral prefrontal cortex in schizophrenia, bipolar disorder, and major depression

BACKGROUND

Retinoids regulate gene expression in different cells and tissues at the transcriptional level. Retinoic acid transcriptionally regulates downstream regulatory molecules, including enzymes, transcription factors, cytokines, and cytokine receptors. Animal models indicate an involvement of retinoid signaling pathways in the regulation of synaptic plasticity and learning, especially in the hippocampus. Retinoic acid-inducible or induced gene 1 (RAI-1) is induced during neuronal differentiation, and was associated with the severity of the phenotype and response to medication in schizophrenic patients.

METHODS

In the present study, we used immunohistochemistry to investigate the expression of RAI-1 in 60 brains from the Stanley Neuropathology Consortium (15 cases each from controls and from patients with schizophrenia, bipolar disorder, and major depression). Rating scores for density and intensity were determined in the dorsolateral prefrontal cortex.

RESULTS

All four groups showed high interindividual variation. RAI-1-positive cells were identified as neurons and astrocytes. Significantly increased intensities in cortical neurons were noted in all three major psychiatric groups compared with controls. The density of RAI-1-positive neurons was increased (P=0.06) in schizophrenia and bipolar disorder. In bipolar disorder, RAI-1-positive astrocytes in gray matter showed a significantly increased intensity and compound value. Thus, a significant increase in the parameters measured was found in schizophrenia, bipolar disorder, and major depression.

CONCLUSION

Our study shows a significant increase in expression of RAI-1 in the brains from patients with schizophrenia, bipolar disorder, or major depression. The increased expression might reflect altered signaling pathways, like that for retinoic acid. The underlying mechanisms leading to the increased expression and its functional consequences are so far unknown, and remain to be investigated in future studies.

Highly immunostimulatory RNA derived from a Sendai virus defective viral genome

Defective viral genomes (DVGs) are generated during virus replication. DVGs bearing complementary ends are strong inducers of dendritic cell (DC) maturation and of the expression of antiviral and pro-inflammatory cytokines by triggering signaling of the RIG-I family of intracellular pattern recognition receptors. Our data show that DCs stimulated with virus containing DVGs have an enhanced ability to activate human T cells and can induce adaptive immunity in mice. In addition, we describe the generation of a short Sendai virus (SeV)-derived DVG RNA (DVG-324) that maintains strong immunostimulatory activity in vitro and in vivo. DVG-324 induced high levels of Ifnb expression when transfected into cells and triggered fast expression of pro-inflammatory cytokines and mobilization of dendritic cells when injected into the footpad of mice. Importantly, DVG-324 enhanced the production of antibodies to a prototypic vaccine after a single intramuscular immunization in mice. Notably, the pro-inflammatory cytokine profile induced by DVG-324 was different from that induced by poly I:C, the only viral RNA analog currently used as an immunostimulant in vivo, suggesting a distinct mechanism of action. SeV-derived oligonucleotides represent novel alternatives to be harnessed as potent adjuvants for vaccination.