Hypoxia-Inducible Factor 1 Alpha-Mediated RelB/APOBEC3B Down-regulation Allows Hepatitis B Virus Persistence.

BACKGROUND AND AIMS: Therapeutic strategies against HBV focus, among others, on the activation of the immune system to enable the infected host to eliminate HBV. Hypoxia-inducible factor 1 alpha (HIF1α) stabilization has been associated with impaired immune responses. HBV pathogenesis triggers chronic hepatitis-related scaring, leading inter alia to modulation of liver oxygenation and transient immune activation, both factors playing a role in HIF1α stabilization. APPROACH AND RESULTS: We addressed whether HIF1α interferes with immune-mediated induction of the cytidine deaminase, apolipoprotein B mRNA editing enzyme catalytic subunit 3B (APOBEC3B; A3B), and subsequent covalently closed circular DNA (cccDNA) decay. Liver biopsies of chronic HBV (CHB) patients were analyzed by immunohistochemistry and in situ hybridization. The effect of HIF1α induction/stabilization on differentiated HepaRG or mice ± HBV ± LTßR-agonist (BS1) was assessed in vitro and in vivo. Induction of A3B and subsequent effects were analyzed by RT-qPCR, immunoblotting, chromatin immunoprecipitation, immunocytochemistry, and mass spectrometry. Analyzing CHB highlighted that areas with high HIF1α levels and low A3B expression correlated with high HBcAg, potentially representing a reservoir for HBV survival in immune-active patients. In vitro, HIF1α stabilization strongly impaired A3B expression and anti-HBV effect. Interestingly, HIF1α knockdown was sufficient to rescue the inhibition of A3B up-regulation and -mediated antiviral effects, whereas HIF2α knockdown had no effect. HIF1α stabilization decreased the level of v-rel reticuloendotheliosis viral oncogene homolog B protein, but not its mRNA, which was confirmed in vivo. Noteworthy, this function of HIF1α was independent of its partner, aryl hydrocarbon receptor nuclear translocator. CONCLUSIONS: In conclusion, inhibiting HIF1α expression or stabilization represents an anti-HBV strategy in the context of immune-mediated A3B induction. High HIF1α, mediated by hypoxia or inflammation, offers a reservoir for HBV survival in vivo and should be considered as a restricting factor in the development of immune therapies.

Needs for an Integration of Specific Data Sources and Items - First Insights of a National Survey Within the German Center for Infection Research.

State-subsidized programs develop medical data integration centers in Germany. To get infection disease (ID) researchers involved in the process of data sharing, common interests and minimum data requirements were prioritized. In 06/2019 we have initiated the German Infectious Disease Data Exchange (iDEx) project. We have developed and performed an online survey to determine prioritization of requests for data integration and exchange in ID research. The survey was designed with three sub-surveys, including a ranking of 15 data categories and 184 specific data items and a query of available 51 data collecting systems. A total of 84 researchers from 17 fields of ID research participated in the survey (predominant research fields: gastrointestinal infections n=11, healthcare-associated and antibiotic-resistant infections n=10, hepatitis n=10). 48% (40/84) of participants had experience as medical doctor. The three top ranked data categories were microbiology and parasitology, experimental data, and medication (53%, 52%, and 47% of maximal points, respectively). The most relevant data items for these categories were bloodstream infections, availability of biomaterial, and medication (88%, 87%, and 94% of maximal points, respectively). The ranking of requests of data integration and exchange is diverse and depends on the chosen measure. However, there is need to promote discipline-related digitalization and data exchange.

Redox sensitivity of the MyD88 immune signaling adapter.

The transcription factor nuclear factor-κB (NF-κB) mediates expression of key genes involved in innate immunity and inflammation. NF-κB activation has been repeatedly reported to be modulated by hydrogen peroxide (H2O2). Here, we show that the NF-κB-activating signaling adapter myeloid differentiation primary response gene 88 (MyD88) is highly sensitive to oxidation by H2O2 and may be redox-regulated in its function, thus facilitating an influence of H2O2 on the NF-κB signaling pathway. Upon oxidation, MyD88 forms distinct disulfide-linked conjugates which are reduced by the MyD88-interacting oxidoreductase nucleoredoxin (Nrx). MyD88 cysteine residues functionally modulate MyD88-dependent NF-κB activation, suggesting a link between MyD88 thiol oxidation state and immune signaling.