Role of IL-6 and IL-1beta in reactivation by acetylcholine of latently infecting pseudorabies virus

Establishment of an Alzheimer's disease model with latent herpesvirus infection using PS2 and Tg2576 double transgenic mice

A relationship between Alzheimer’s disease and herpes simplex virus infection has been pointed out. We established a model of Alzheimer’s disease with a latent herpesvirus infection using a mouse model of Alzheimer’s disease (PS2Tg2576) and examined the changes in amyloid β (Aβ) in the brain. We crossbred female PS2 mice with male Tg2576 hemi mice and chose PS2Tg2576 mice. After priming 5-week-old male mice with anti-pseudorabies virus swine serum, we challenged the mouse with 100 LD₅₀ of YS-81, a wild-type strain of pseudorabies virus. The viral DNA was detected in nasal swabs by a reactivation test and in the trigeminal ganglia. At two months after infection, the Aβ40 and Aβ42 levels in the brains of the mice of the latently infected group were increased; the increase was greater than that observed in the noninfected group. Latent pseudorabies virus infection was established in PS2Tg2576 mice and the level of Aβ increased with the reactivation of the latent virus.

Classical swine fever virus NS5A protein changed inflammatory cytokine secretion in porcine alveolar macrophages by inhibiting the NF-κB signaling pathway

Background

Classical swine fever (CSF) caused by CSF virus (CSFV) is a highly contagious disease of the pigs. A number of studies have suggested that CSFV non-structural (NS) 5A protein is involved in CSFV-associated pathogenesis, but its mechanism is still uncertain. The aim of this study was to investigate the roles of NS5A protein in CSFV-associated pathogenesis in cultured porcine alveolar macrophages (PAMs).

Methods

After PAMs cultured in vitro were transfected with CSFV NS5A, the alterations in IL-1β, IL-6 and TNF-α expression were determined by ELISA, the RIG-I signaling activity related to inflammatory cytokine secretion was investigated by Western blot and Immunofluorescent staining.

Results

It was suggested that, the stable expressed CSFV NS5A solely had no influence on the expressions of inflammatory cytokines IL-1β, IL-6 and TNF-α in PAMs Moreover, NS5A protein could suppressed IL-1β, IL-6 and TNF-α expression induced by poly(I:C). It was also showed that NS5A protein did not impair the expressions of RIG-I, MDA5, IPS-1, NF-κB and IkBα in cells without poly(I:C) stimulation. Protein expressions of RIG-I, MDA5, IPS-1, NF-κB were not disrupted by NS5A protein in poly(I:C)-stimulated cells, while poly(I:C)-induced NF-κB nuclear translocation and activity was obviously suppressed by this protein. A suppression in poly(I:C)-induced IkBα degradation in NS5A-expressing cells was also observed.

Conclusion

These data indicated that CSFV NS5A protein could inhibit the secretion of inflammatory cytokine induced by poly(I:C) through the suppression of the NF-κB signaling pathway, indicating the participation of CSFV NS5A protein in the pathogenesis of CSFV.

Analysis of the mechanism of reactivation of latently infecting pseudorabies virus by acetylcholine

In this study, the effect of cholinergic or adrenergic inhibitors on the reactivation of latent Pseudorabies virus (PRV) was analyzed to clarify the mechanism of the reactivation of latent PRV by acetylcholine. For acetylcholine inhibition, latently infected mice were injected with scopolamine or succynilcholine before acetylcholine stimulation. For sympathetic blocking, mice were preinjected intraperitoneally with phenoxybenzamine or propranolol. The signals to both acetylcholine receptors had no relationship to the reactivation of latent PRV, and both sympathetic blockers showed inhibition of PRV reactivation by acetylcholine. In our reactivation model, a large amount of acetylcholine may stimulate the sympathetic nerve system in some way to reactivate the virus.

Usage of analgesic in a murine model infected latently with pseudorabies virus

Butorphanol tartrate (BT) was injected into mice before injection with acetylcholine in a murine model infected latently with pseudorabies virus. The analgesic effect and its influence on virus reactivation were observed. Mice preinjected with BT showed suppression of screaming, moving and excitation and the same level of movement after excitation as mice injected with PBS. In the group injected with BT i.p., one mouse died and another developed diarrhea with increased virus excretion. These results showed that BT has analgesic effects by both injection routes, s.c. and i.p.; however, BT induced death as a side effect, especially with i.p. injection. The injection route for BT should therefore be investigated further.