[3-Deazaadenosine (3-DAA) accelerates Japanese encephalitis virus replication and down-regulates levels of inflammatory factors in mouse and hamster cells].

Objective To investigate the effect of 3-deazaadenosine (3-DAA), an N6-methyladenosine (m6A) methylation modification inhibitor, on the replication of the Japanese encephalitis virus (JEV). Methods Neuro2a mouse neuroblastoma cells, N9 mouse microglial cells, and BHK baby hamster kidney cells were exposed to JEV and then treated with 3-DAA. JEV was also injected into the footpad of adult C57BL/6 mice, which were then administered 3-DAA intraperitoneally. Real-time quantitative PCR was utilized to measure mRNA expression levels of JEV, interleukin 1ß (IL-1ß), IL-6, tumor necrosis factor α (TNF-α), monocyte chemoattractant protein 1 (MCP-1), inducible nitric oxide synthase (iNOS), arginase 1 (Arg1), interferon (IFN)-α, IFN-ß, IFN-γ, and C-X-C motif chemokine ligand 10 (CXCL10) in the cells and mouse brain tissues. Western blot analysis was used to detect JEV protein expression in the cells and mouse brain tissues. Furthermore, the survival of the mice was monitored and pathological changes in mouse brains were observed via hematoxylin and eosin (HE) staining. Results 3-DAA had a dose-dependent effect on the replication of RNA and protein expression of JEV in both BHK, N9, Neuro 2α cells and mouse brain tissues, which resulted in rapid progression of JEV infection in mice and a decrease in their survival rate. Furthermore, 3-DAA suppressed the expression of inflammatory factors such as IL-6, TNF-α, CXCL10, IL-1ß and iNOS, thus weakening the immune response. Conclusion 3-DAA promotes JEV infection and hastens death of infected cells and mice, indicating that m6A modification may negatively regulate JEV replication.

N6-methyladenosine modification positively regulate Japanese encephalitis virus replication.

N6-methyladenosine (m6A) is present in diverse viral RNA and plays important regulatory roles in virus replication and host antiviral innate immunity. However, the role of m6A in regulating JEV replication has not been investigated. Here, we show that the JEV genome contains m6A modification upon infection of mouse neuroblast cells (neuro2a). JEV infection results in a decrease in the expression of m6A writer METTL3 in mouse brain tissue. METTL3 knockdown by siRNA leads to a substantial decrease in JEV replication and the production of progeny viruses at 48 hpi. Mechanically, JEV triggered a considerable increase in the innate immune response of METTL3 knockdown neuro2a cells compared to the control cells. Our study has revealed the distinctive m6A signatures of both the virus and host in neuro2a cells infected with JEV, illustrating the positive role of m6A modification in JEV infection. Our study further enhances understanding of the role of m6A modification in Flaviviridae viruses.

[Analysis for 171 cases of esophageal foreign bodies impacted in upper esophagus with endoscopic treatment].

OBJECTIVE: To assess the effectiveness and complications of rigid endoscopy (RE) and flexible endoscopy (FE) for the extraction of esophageal foreign bodies (FBs) in adults. METHODS: A retrospective analysis was conducted on the medical records of 171 adult patients with the upper esophageal FB impaction treated at Peking University Third Hospital, Beijing, China, between January 2008 and December 2012. RESULTS: In the study, 126 patients with the upper esophageal foreign body impaction were treated with RE, while 45 patients received FE. (1)The size of FBs in FE group was the same as RE group(P = 0.495, P = 0.125). (2)The period impacted in the esophagus of RE group (25.8 ± 28.6) h was longer than that of FE group (13.9 ± 14.5) h (P = 0.009). (3)71.4% of the patients in RE and 88.9% in FE group went to hospital for treatment within 24 hours from being impacted, while 15.1% in RE group and 8.9% in FE group were between 24 and 48 hours.13.5% in RE and 2.2% in FE group went to hospital beyond 48 hours.(4)The proportion of FBs puncturing into one or two esophageal walls in RE group (67.5%) was higher than that in FE group (35.6%).(5) The positive rates with the upper gastrointestinal barium contrast and chest X-ray or abdominal plain film were 98.3%,23.6% and 100%,14.3% for diagnosing esophageal FBs in RE and FE groups.(6)The successful rate, complication rate and perforation rate were 100%,38.1% and 6.3%and 95.6%,48.9%,and 2.2% in RE and FE groups, respectively with no statistical difference (P > 0.05). CONCLUSION: Both RE and FE were effective in the extraction of upper esophageal FBs with no difference in the complication and perforation rates. But FE was cheaper and no need for general anesthesia.

[Complication related factors and efficacy with flexible endoscopy of 101 esophageal foreign bodies].

OBJECTIVE: To analyze the related factors of complications and treatment efficacy with flexible endoscopy for esophageal foreign body (FB). METHODS: In a retrospective study with consecutive data, 101 adults including 52 males and 49 females with esophageal FB impaction between January 2005 and December 2012 admitted into Department of Gastroenterology's Endoscopic Unit at Peking University Third Hospital were included, aged (49 ± 21) years. RESULTS: (1) FB impaction in upper and middle esophagus accounted for 87.1% (n = 88) of all esophageal FBs. No significant difference existed in interval time from impaction to removal of FB impacted between upper, middle and lower esophagus (P > 0.05) . (2) Patients with esophageal FB seeking hospital treatment accounted for 82.2% (n = 83) within 24 h and 99.0% (n = 100) within 48 h. Food lump, fish bone, chicken bone and fruit seeds accounted for 76.2% (n = 77). (3) Positive rates were 91.3% (21/23) and 24.1% (7/29) with upper gastrointestinal barium contrast and chest or abdominal plain film. The success rate was 94.1% (n = 95) with flexible endoscopy for removal of FB. (4) Denture was the most difficult FB for removal. Four patients in all 11 patients with denture impacted were not removed successfully with flexible endoscopy. (5) The complication (except for mild scratch) rate was 48.5% (n = 49) and the perforation rate 3.0% (n = 3) . Whether complications took place or not was independent of age, location of impaction, time from impaction to removal and size of FB (all P > 0.05) , but dependent on piercing into esophageal wall, concomitant with esophageal stricture and types of FB (all P < 0.01) . Whether perforation or not was independent of any above factor. CONCLUSION: Esophageal FB should be removed as soon as possible within 24 h especially for those with sharp edges and piercing into esophageal wall.