Increased viperin expression induced by avian infectious bronchitis virus inhibits viral replication by restricting cholesterol synthesis: an in vitro study.

With the emergence of new variant strains resulting from high mutation rates and genome recombination, avian infectious bronchitis virus (IBV) has caused significant economic losses to the poultry industry worldwide. Little is known about the underlying mechanisms of IBV-host interactions, particularly how IBV utilizes host metabolic pathways for efficient viral replication and transmission. In the present study, the effects of the cell membrane, viral envelope membrane, and viperin-mediated cholesterol synthesis on IBV replication were explored. Our results revealed significant increase in cholesterol levels and the expression of viperin after IBV infection. Acute cholesterol depletion in the cell membrane and viral envelope membrane by treating cells with methyl-ß-cyclodextrin (MßCD) obviously inhibited IBV replication; thereafter, replenishment of the cell membrane with cholesterol successfully restored viral replication, and direct addition of exogenous cholesterol to the cell membrane significantly promoted IBV infection during the early stages of infection. In addition, overexpression of viperin effectively suppressed cholesterol synthesis, as well as IBV replication, whereas knockdown of viperin (gene silencing with siRNA targeting viperin, siViperin) significantly increased IBV replication and cholesterol levels, whereas supplementation with exogenous cholesterol to viperin-transfected cells markedly restored viral replication. In conclusion, the increase in viperin induced by IBV infection plays an important role in IBV replication by affecting cholesterol production, providing a theoretical basis for understanding the pathogenesis of IBV and discovering new potential antiviral targets.

In vivo antiviral effect of plant essential oils against avian infectious bronchitis virus.

BACKGROUND: Infectious bronchitis virus (IBV) leads to huge economic losses in the poultry industry worldwide. The high levels of mutations of IBV render vaccines partially protective. Therefore, it is urgent to explore an effective antiviral drug or agent. The present study aimed to investigate the in vivo anti-IBV activity of a mixture of plant essential oils (PEO) of cinnamaldehyde (CA) and glycerol monolaurate (GML), designated as Jin-Jing-Zi. RESULTS: The antiviral effects were evaluated by clinical signs, viral loads, immune organ indices, antibody levels, and cytokine levels. The infection rates in the PEO-M (middle dose) and PEO-H (high dose) groups were significantly lower than those in the prevention, positive drug, and PEO-L (low dose) groups. The cure rates in the PEO-M and PEO-H groups were significantly higher than those in the prevention, positive drug, and PEO-L groups, and the PEO-M group had the highest cure rate of 92.31%. The symptom scores and IBV mRNA expression levels were significantly reduced in the PEO-M group. PEO significantly improved the immune organ indices and IBV-specific antibody titers of infected chickens. The anti-inflammatory factor levels of IL-4 and IFN-γ in the PEO-M group maintained high concentrations for a long time. The IL-6 levels in the PEO-M group were lower than those in prevention, positive drug, and PEO-L groups. CONCLUSION: The PEO had remarkable inhibition against IBV and the PEO acts by inhibiting virus multiplication and promoting immune function, suggesting that the PEO has great potential as a novel anti-IBV agent for inhibiting IBV infection.

[The effect of inhalable titanium dioxide on the oxidative stress among occupational population].

OBJECTIVE: To investigate the inhalable titanium dioxide exposure level and make an assessment of its oxidative effect on occupational exposed population. METHODS: A total of 7 workers occupationally exposing to inhalable titanium dioxide were recruited into the study. The basic information and occupational history were collected by interview, while their blood sample (10 ml for each subject) were collected before and after the investigation, respectively. Pre- and post-work shift urine samples (60 ml for each subject) were collected for 29 days consecutively. The daily personal titanium dioxide exposure level, temperature and relative humidity were detected too. Urinary 8-hydroxy-deoxyguanosine (8-OHdG) and serum high-sensitivity C-reactive protein (hs-CRP) were detected by ELISA and latex immunoturbidimetric assay, respectively. RESULTS: The mean concentration of air inhalable titanium dioxide was (1.194 ± 1.015) mg/m(3). Serum hs-CRP level before and after the investigation was (1.13 ± 1.08), (1.33 ± 1.01) mg/L, respectively. No statistical significance was observed between hs-CRP level before and after the investigation (t = -0.848, P = 0.425). Pre- and post-work shift urinary 8-OHdG was (3.51 ± 1.39), (3.65 ± 1.06) µmol/mol Cr, respectively. A positive correlation was found between the concentration of inhalable titanium dioxide and the changes of 8-OHdG level (r = 0.192, t = 2.09, P = 0.039). Linear mixed-effect models, adjusted by work shift, years of employment, age, body mass index, smoking status, temperature and relative humidity, showed no significant exposure-respond trend between the inhalable titanium dioxide concentration and 8-OHdG level (ß = 0.288, t = 1.940, P = 0.055). CONCLUSION: Our findings do not support the potential link between occupationally exposure to inhalable titanium dioxide and high induction of DNA oxidative stress.