Zika virus (ZIKV), formerly a neglected pathogen, has recently been associated with microcephaly in fetuses 1 , and with Guillian-Barré syndrome in adults 2 . Here we present the 3.7 Å resolution cryoelectron microscopy structure of ZIKV, and show that the overall architecture of the virus is similar to that of other flaviviruses. Sequence and structural comparisons of the ZIKV envelope (E) protein with other flaviviruses show that parts of the E protein closely resemble the neurovirulent West Nile and Japanese encephalitis viruses, while others are similar to dengue virus (DENV). However, the contribution of the E protein to flavivirus pathobiology is currently not understood. The virus particle was observed to be structurally stable even when incubated at 40 °C, in sharp contrast to the less thermally stable DENV 3 . This is also reflected in the infectivity of ZIKV compared to DENV serotypes 2 and 4 (DENV2 and DENV4) at different temperatures. The cryoelectron microscopy structure shows a virus with a more compact surface. This structural stability of the virus may help it to survive in the harsh conditions of semen 4 , saliva 5 and urine 6 . Antibodies or drugs that destabilize the structure may help to reduce the disease outcome or limit the spread of the virus.Zika virus (ZIKV), a flavivirus, is thought to be principally transmitted to humans by the mosquito (Aedes aegypti) vector. Other flaviviriuses include West Nile virus (WNV), Japanese encephalitis virus (JEV), dengue virus (DENV) and yellow fever virus (YFV). ZIKV generally causes a mild disease. However, when pregnant women are infected with ZIKV, there is an increased risk of developing microcephaly in the fetus 1 .Retrospective analysis of data collected from a ZIKV outbreak in French Polynesia in 2013-2014 showed association of the virus with microcephaly 7 . Here we present the 3.7 Å resolution structure of ZIKV strain H/PF/2013 isolated during that outbreak 8 .For cryo-electron microscopy (cryoEM) studies, ZIKV was grown in the mosquito cell line at 28 °C and purified at 4 °C by polyethylene glycol precipitation, a sucrose cushion, followed by a potassium tartrate gradient. The gel analysis of the purified sample suggested it contained mostly mature virus (Extended Data Fig. 1). The ZIKV samples were incubated at 28 °C, 37 °C and 40 °C (mimicking high fever) for 30 min, before imaging by cryoEM (Fig. 1a). At 28 °C, there were broken and shrivelled particles together with some smooth surfaced particles (about 500 Å in diameter), similar to the compact DENV mature particles. Conversely, samples incubated at 37 °C and 40 °C showed many more smooth surfaced particles. The presence of a larger fraction of shrivelled particles at 28 °C could be due to the exposure of particles to high osmolality during purification. We speculate that ZIKV particles may expand into smooth surfaced particles when incubated at higher temperatures, making the lipid envelope more fluid, and allowing the structure to revert to its normal state. Some strains of DENV2 (New G...
<b><i>Background:</i></b> Primary liver cancer, around 90% are hepatocellular carcinoma in China, is the fourth most common malignancy and the second leading cause of tumor-related death, thereby posing a significant threat to the life and health of the Chinese people. <b><i>Summary:</i></b> Since the publication of <i>Guidelines for Diagnosis and Treatment of Primary Liver Cancer (2017 Edition)</i> in 2018, additional high-quality evidence has emerged with relevance to the diagnosis, staging, and treatment of liver cancer in and outside China that requires the guidelines to be updated. The new edition <i>(2019 Edition)</i> was written by more than 70 experts in the field of liver cancer in China. They reflect the real-world situation in China regarding diagnosing and treating liver cancer in recent years. <b><i>Key Messages:</i></b> Most importantly, the new guidelines were endorsed and promulgated by the Bureau of Medical Administration of the National Health Commission of the People’s Republic of China in December 2019.
The results of this study suggest that autologous adipose-derived SVF treatment is safe and can effectively relief pain, improve function, and repair cartilage defects in patients with knee osteoarthritis.
The physiological role of microRNAs (miRNAs) in osteoblast differentiation remains elusive. Exosomal miRNAs isolated from human bone marrow-derived mesenchymal stem cells (BMSCs) culture were profiled using miRNA arrays containing probes for 894 human matured miRNAs. Seventy-nine miRNAs (∼8.84%) could be detected in exosomes isolated from BMSC culture supernatants when normalized to endogenous control genes RNU44. Among them, nine exosomal miRNAs were up regulated and 4 miRNAs were under regulated significantly (Relative fold>2, p<0.05) when compared with the values at 0 day with maximum changes at 1 to 7 days. Five miRNAs (miR-199b, miR-218, miR-148a, miR-135b, and miR-221) were further validated and differentially expressed in the individual exosomal samples from hBMSCs cultured at different time points. Bioinformatic analysis by DIANA-mirPath demonstrated that RNA degradation, mRNA surveillance pathway, Wnt signaling pathway, RNA transport were the most prominent pathways enriched in quantiles with differential exosomal miRNA patterns related to osteogenic differentiation. These data demonstrated exosomal miRNA is a regulator of osteoblast differentiation.
Structures of flavivirus (dengue virus and Zika virus) particles are known to near-atomic resolution and show detailed structure and arrangement of their surface proteins (E and prM in immature virus or M in mature virus). By contrast, the arrangement of the capsid proteins: RNA complex, which forms the core of the particle, is poorly understood, likely due to inherent dynamics. Here, we stabilize immature Zika virus via an antibody that binds across the E and prM proteins, resulting in a subnanometer resolution structure of capsid proteins within the virus particle. Fitting of the capsid protein into densities shows the presence of a helix previously thought to be removed via proteolysis. This structure illuminates capsid protein quaternary organization, including its orientation relative to the lipid membrane and the genomic RNA, and its interactions with the transmembrane regions of the surface proteins. Results show the capsid protein plays a central role in the flavivirus assembly process.
PRSS3 plays an important role in the progression, metastasis and prognosis of human pancreatic cancer. Targeting the PRSS3 signalling pathway may be an effective and feasible approach for treatment of this lethal cancer.
Bromodomain 4 (BRD4) is an epigenetic regulator that, when inhibited, has anti-cancer effects. In this study, we investigated whether BRD4 could be a target for treatment of human hepatocellular carcinoma (HCC). We show that BRD4 is overexpressed in HCC tissues. Suppression of BRD4, either by siRNA or using JQ1, a pharmaceutical BRD4 inhibitor, reduced cell growth and induced apoptosis in HCC cell lines while also slowing HCC xenograft tumor growth in mice. JQ1 treatment induced G1 cell cycle arrest by repressing MYC expression, which led to the up-regulation of CDKN1B (P27). JQ1 also de-repressed expression of the pro-apoptotic BCL2L11 (BIM). Moreover, siRNA knockdown of BIM attenuated JQ1-triggered apoptosis in HCC cells, suggesting an essential role for BIM in mediating JQ1 anti-HCC activity.
The rapid spread of Zika virus (ZIKV), which causes microcephaly and Guillain-Barré syndrome, signals an urgency to identify therapeutics. Recent efforts to rescreen dengue virus human antibodies for ZIKV cross-neutralization activity showed antibody C10 as one of the most potent. To investigate the ability of the antibody to block fusion, we determined the cryoEM structures of the C10-ZIKV complex at pH levels mimicking the extracellular (pH8.0), early (pH6.5) and late endosomal (pH5.0) environments. The 4.0 Å resolution pH8.0 complex structure shows that the antibody binds to E proteins residues at the intra-dimer interface, and the virus quaternary structure-dependent inter-dimer and inter-raft interfaces. At pH6.5, antibody C10 locks all virus surface E proteins, and at pH5.0, it locks the E protein raft structure, suggesting that it prevents the structural rearrangement of the E proteins during the fusion event—a vital step for infection. This suggests antibody C10 could be a good therapeutic candidate.
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