DENV type 2 NS1 (a.a. 777-1131)

Ethnopharmacological relevance: Honeysuckle (Lonicera japonica Thunb.), a traditional Chinese herb, has widely been used to treat pathogen infection. However, the underlying-mechanism remains elusive. Aims of the study: To reveal the host microRNA (miRNA) profile with the anti-viral activity after honeysuckle treatment. Materials and methods: Here we reveal the differentially expressed miRNAs by Solexa (R) deep sequencing from the blood of human and mice after the aqueous extract treatment. Among these overexpressed innate miRNAs both in human and mice, let-7a is able to target the NS1 region (nt 3313-3330) of dengue virus (DENV) serotypes 1, 2 and 4 predicated by the target predication software. Results: We confirmed that let-7a could target DENV2 at the predicated NS1 sequence and suppress DENV2 replication demonstrated by luciferase-reporter activity, RT-PCR, real-time PCR, Western blotting and plaque assay. ICR-suckling mice consumed honeysuckle aqueous extract either before or after intracranial injection with DENV2 showed decreased levels of NS1 RNA and protein expression accompanied with alleviated disease symptoms, decreased virus load, and prolonged survival time. Similar results were observed when DENV2infected mice were intracranially injected with let-7a. Conclusion: We reveal that honeysuckle attenuates DENY replication and related pathogenesis in vivo through induction of let-7a expression. This study opens a new direction for prevention and treatment of DENY infection through induction of the innate miRNA let-7a by honeysuckle.

Background Rapid tests detecting both dengue virus (DENV) NS1 antigen and anti-DENV IgM and IgG antibodies facilitate diagnosis of dengue fever (DF) in resource-poor settings. Methodology/principal findings 92 acute phase serum samples from patients with a PCR-confirmed DENV infection collected in Lao People's Democratic Republic (Lao PDR) in 2013 and 2015 were analyzed with the SD Bioline Dengue Duo test. A subset of 74 samples was additionally tested with the Platelia NS1 antigen test, the Panbio DENV mu-capture ELISA and the Panbio DENV IgG ELISA. IgM seroconversion was assayed using follow-up samples of 35 patients collected in the convalescent phase. 57.6%, 22.8% and 44.6% of acute phase serum samples tested positive in the SD Bioline Dengue Duo NS1, IgM, and IgG test, respectively. Diagnostic sensitivity of the SD Bioline Dengue Duo NS1 test strongly correlated with viral load, decreased rapidly over the acute phase of the disease, and was significantly reduced in presence of high anti-DENV IgG antibody titers resulting from secondary DENV infection. While a good concordance (Cohen's kappa 0.78) was found between the SD Bioline Dengue Duo NS1 test and the Platelia NS1 antigen ELISA, both the SD Bioline Dengue Duo IgM and IgG test displayed a significantly lower sensitivity than the corresponding ELISA tests. Conclusions/significance The SD Bioline Dengue Duo test is a valuable tool for diagnosis of DENV infections especially when analyzing early acute phase samples with high viral load. Nevertheless, in endemic areas, where secondary flavivirus infections are common, diagnostic sensitivity of the NS1 and IgM test components may be compromised.