Assembly and release of infectious hepatitis C virus involving unusual organization of the secretory pathway

AIM: To determine if calnexin(CANX), RAB1 and alphatubulin were involved in the production of hepatitis C virus(HCV) particles by baby hamster kidney-West Nile virus(BHK-WNV) cells. METHODS: Using a si RNA-based approach complemented with immuno-fluorescence confocal microscope and Western blot studies, we examined the roles of CANX, RAB1 and alpha-tubulin in the production of HCV particles by permissive BHK-WNV cells expressing HCV structural proteins or the full-length genome of HCV genotype 1a. Immuno-fluorescence studies in producer cells were performed with monoclonal antibodies against HCV structural proteins, as well as immunoglobulin from the serum of a patient recently cured from an HCV infection of same genotype. The cellular compartment stained by the serum immunoglobulin was also observedin thin section transmission electron microscopy. These findings were compared with the JFH-1 strain/Huh-7.5 cell model.RESULTS: We found that CANX was necessary for the production of HCV particles by BHK-WNV cells. This process involved the recruitment of a subset of HCV proteins, detected by immunoglobulin of an HCV-cured patient, in a compartment of rearranged membranes bypassing the endoplasmic reticulum-Golgi intermediary compartment and surrounded by mitochondria. It also involved the maturation of N-linked glycans on HCV envelope proteins, which was required for assembly and/or secretion of HCV particles. The formation of this specialized compartment required RAB1; upon expression of HCV structural genes, this compartment developed large vesicles with viral particles. RAB1 and alpha-tubulin were required for the release of HCV particles. These cellular factors were also involved in the production of HCVcc in the JFH-1 strain/Huh-7.5 cell system, which involves HCV RNA replication. The secretion of HCV particles by BHK-WNV cells presents similarities with a pathway involving caspase-1; a caspase-1 inhibitor was found to suppress the production of HCV particles from a full-length genome.CONCLUSION: Prior activity of the WNV subgenomic replicon in BHK-21 cells promoted re-wiring of host factors for the assembly and release of infectious HCV in a caspase-1-dependent mechanism.

Toward a molecular mechanism-based prediction of CRISPR-Cas9 targeting effects

The CRISPR-Cas9 system,serving as a powerful genome-editing technology,has revolutionized the life sciences.However,it exhibits off-target activities that may present severe problems in clinical applications.Although a great number of in silico models have been developed to predict CRISPR targeting efficiency and specificity,they are running into a bottleneck with the lack of a mechanistic understanding of the on-and off-target activities of Cas9.

Exploring the utility of the Chasing Principle:influence of drug-free SNEDDS composition on solubilization of carvedilol, cinnarizine and R3040 in aqueous suspension

This study assessed the influence of the composition of drug-free SNEDDS co-dosed with aqueous suspensions of carvedilol(CAR), cinnarizine(CIN) or R3040 on drug solubilization in a twocompartment in vitro lipolysis model. Correlation of drug log P or solubility in SNEDDS with drug solubilization during in vitro lipolysis in the presence of drug-free SNEDDS was assessed. SNEDDS with varying ratios of soybean oil:Maisine 35-1(1:1, w/w) and Kolliphor RH40, with ethanol at 10%(w/w) were used. SNEDDS were named F65, F55 and F20(numbers refer to the percentage of lipids) and aqueous suspensions without drug-free SNEDDS(F0) were also analyzed. While the ranking order of drug solubilization was F65? F55? F204F0 for CAR; F65? F554F204F0 for CIN and F65? F55? F204F0 for R3040-with higher CAR solubilization than for R3040 and CIN-the ranking of S_(eq)of CAR, CIN and R3040 in SNEDDS was F65 o F55o F20, F65? F554F20 and F654F554F20, respectively. Therefore, the composition of SNEDDS influenced the solubilization of CIN, but not CAR and R3040. Furthermore, high S_(eq) in SNEDDS did not reflect high drug solubilization. As CAR(log P 3.8) showed higher solubilization than CIN(log P 5.8) and R3040(log P 10.4), a correlation between drug log P and drug solubilization was observed.

Doubling down with CAR-T cell cancer immunotherapy:a two-step recognition circuit enables discrimination between target antigen high and low cancer cells

In a recent article published in Science by Hernandez-Lopez et al.chimeric antigen receptor(CAR)expressing T(CAR-T)cells with a two-step recognition system successfully discriminated between target cells expressing high and low levels of their target antigen,which enabled the specific rejection of solid tumour xenograft.

A Pseudopaline Fluorescent Probe for the Selective Detection of Pseudomonas aeruginosa

The rise of resistance to all known antibiotics is a global crisis.In addition to novel treatment options,there is an urgent need to develop rapid,specific,sensitive,and reliable diagnostic methods to detect pathogenic bacteria in clinical samples and reduce the overuse and misuse antibiotics.Pseudopaline,a metallophore produced by the human pathogen Pseudomonas aeruginosa,transports divalent metal ions via a dedicated active transport system,making it an ideal carrier for a second functional moiety.