Peripheral Nerve Injury Induced by Japanese Encephalitis Virus in C57BL/6 Mouse.

Japanese encephalitis virus (JEV), with neurotoxic and neuroinvasive properties, is the major cause of human viral encephalitis in Asia. Although Guillain-Barré syndrome caused by JEV infections is not frequent, a few cases have been reported in recent years. To date, no existing animal model for JEV-induced peripheral nerve injury (PNI) has been established, and thus the pathogenic mechanism is not clarified. Therefore, an animal model is urgently required to clarify the correlation between JEV infection and PNI. In the present study, we used JEV GIb strain of NX1889 to establish a mouse model of JEV infection. The general neurological signs emerged on day 3 of modeling. The motor function continued to deteriorate, reaching a maximum at 8 to 13 days postinfection (dpi) and gradually recovered after 16 dpi. The injuries of 105 PFU and 106 PFU groups were the most severe. Transmission electron microscopy and immunofluorescence staining showed varying degrees of demyelination and axonal degeneration in the sciatic nerves. The electrophysiological recordings demonstrated the presence of demyelinating peripheral neuropathy with reduced nerve conduction velocity. The decreased amplitudes and the prolonged end latency revealed axonal-type motor neuropathy. Demyelination is predominant in the early stage, followed by axonal injury. The expression level of JEV-E protein and viral RNA was elevated in the injured sciatic nerves, suggesting that it may cause PNI at the early stage. Inflammatory cell infiltration and increased inflammatory cytokines indicated that neuroinflammation is involved in JEV-induced PNI. IMPORTANCE JEV is a neurotropic flavivirus belonging to the Flaviviridae family and causes high mortality and disability rates. It invades the central nervous system and induces acute inflammatory injury and neuronal death. Thus, JEV infection is a major global public health concern. Previously, motor dysfunction was mainly attributed to central nervous system damage. Our knowledge regarding JEV-induced PNI is vague and neglected. Therefore, a laboratory animal model is essential. Herein, we showed that C57BL/6 mice can be used to study JEV-induced PNI through multiple approaches. We also demonstrated that viral loads might be positively correlated with lesion severity. Therefore, inflammation and direct virus infection may be the putative mechanisms underlying JEV-induced PNI. The results of this study laid the foundation for further elucidation of the pathogenesis mechanisms of PNI caused by JEV.

Label-free proteomics-based analysis of peripheral nerve injury induced by Japanese encephalitis virus.

Japanese encephalitis (JE) is just an acute encephalitis syndrome contributed to Japanese encephalitis virus (JEV) infection. It the chief causes of viral encephalitis in Asia. In recent years, association of JEV infection with neurological problems such as Guillain-Barré syndrome(GBS) had reported. Nevertheless, its potential pathogenic mechanism has not previously been reported. Therefore, it is urgent to study the relationship between peripheral nerve injury (PNI) and JEV infection. Here, we use the liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique to make out the protein expression levels of mice sciatic nerve between JEV infection group and the sham group. In general, 4303 proteins were designated by MS, and 187 differentially expressed proteins(DEPs) were found. There were 105 proteins up-regulated in the injured sciatic nerve, and 82 proteins were down-regulated. Functional enrichment analysis of DEPs showed that the up-regulated proteins were mainly related to immune regulatory response, and down-regulated proteins were related to ribosomal structural components and translation. SIGNIFICANCE: The Japanese encephalitis virus, a member of the flavivirus, is a Mosquito borne virus. It leads to central nervous system injury by the immune response and inflammation in the brain. In addition, the virus also gave rise to PNI. It is a major public health problem in Asia. The diversity of clinical symptoms has brought serious challenges to the diagnosis and treatment of the disease. Label-Free Proteomics was undertaken to explore the potential mechanisms between JEV and peripheral nervous system in this study. It provided strong evidence that tissue damage is caused by the immune-mediated mechanisms rather than the virus, which offers a basis for the prevention of the disease and further looking for treatment targets.