The ESCRT System Is Required for Hepatitis C Virus Production

BACKGROUND: Recently, lipid droplets have been found to be involved in an important cytoplasmic organelle for hepatitis C virus (HCV) production. However, the mechanisms of HCV assembly, budding, and release remain poorly understood. Retroviruses and some other enveloped viruses require an endosomal sorting complex required for transport (ESCRT) components and their associated proteins for their budding process. METHODOLOGY/PRINCIPAL FINDINGS: To determine whether or not the ESCRT system is needed for HCV production, we examined the infectivity of HCV or the Core levels in culture supernatants as well as HCV RNA levels in HuH-7-derived RSc cells, in which HCV-JFH1 can infect and efficiently replicate, expressing short hairpin RNA or siRNA targeted to tumor susceptibility gene 101 (TSG101), apoptosis-linked gene 2 interacting protein X (Alix), Vps4B, charged multivesicular body protein 4b (CHMP4b), or Brox, all of which are components of the ESCRT system. We found that the infectivity of HCV in the supernatants was significantly suppressed in these knockdown cells. Consequently, the release of the HCV Core into the culture supernatants was significantly suppressed in these knockdown cells after HCV-JFH1 infection, while the intracellular infectivity and the RNA replication of HCV-JFH1 were not significantly affected. Furthermore, the HCV Core mostly colocalized with CHMP4b, a component of ESCRT-III. In this context, HCV Core could bind to CHMP4b. Nevertheless, we failed to find the conserved viral late domain motif, which is required for interaction with the ESCRT component, in the HCV-JFH1 Core, suggesting that HCV Core has a novel motif required for HCV production. CONCLUSIONS/SIGNIFICANCE: These results suggest that the ESCRT system is required for infectious HCV production

Metabolic synergies in the biotransformation of organic and metallic toxic compounds by a saprotrophic soil fungus

The saprotrophic fungus Penicillium griseofulvum was chosen as model organism to study responses to a mixture of hexachlorocyclohexane (HCH) isomers (α-HCH, β-HCH, γ-HCH, δ-HCH) and of potentially toxic metals (vanadium, lead) in solid and liquid media. The P. griseofulvum FBL 500 strain was isolated from polluted soil containing high concentrations of HCH isomers and potentially toxic elements (Pb, V). Experiments were performed in order to analyse the tolerance/resistance of this fungus to xenobiotics, and to shed further light on fungal potential in inorganic and organic biotransformations. The aim was to examine the ecological and bioremedial potential of this fungus verifying the presence of mechanisms that allow it to transform HCH isomers and metals under different, extreme, test conditions. To our knowledge, this work is the first to provide evidence on the biotransformation of HCH mixtures, in combination with toxic metals, by a saprotrophic non-white-rot fungus and on the metabolic synergies involved

Selective gene silencing by viral delivery of short hairpin RNA

RNA interference (RNAi) technology has not only become a powerful tool for functional genomics, but also allows rapid drug target discovery and in vitro validation of these targets in cell culture. Furthermore, RNAi represents a promising novel therapeutic option for treating human diseases, in particular cancer. Selective gene silencing by RNAi can be achieved essentially by two nucleic acid based methods: i) cytoplasmic delivery of short double-stranded (ds) interfering RNA oligonucleotides (siRNA), where the gene silencing effect is only transient in nature, and possibly not suitable for all applications; or ii) nuclear delivery of gene expression cassettes that express short hairpin RNA (shRNA), which are processed like endogenous interfering RNA and lead to stable gene down-regulation. Both processes involve the use of nucleic acid based drugs, which are highly charged and do not cross cell membranes by free diffusion. Therefore, in vivo delivery of RNAi therapeutics must use technology that enables the RNAi therapeutic to traverse biological membrane barriers in vivo. Viruses and the vectors derived from them carry out precisely this task and have become a major delivery system for shRNA. Here, we summarize and compare different currently used viral delivery systems, give examples of in vivo applications, and indicate trends for new developments, such as replicating viruses for shRNA delivery to cancer cells

Polymorphisms in STK17A gene are associated to systemic lupus erythematosus and its clinical manifestations

Systemic lupus erythematosus (SLE) is an autoimmune disorderwith several clinicalmanifestations. SLE etiology has a strong genetic component, which plays a key role in disease's predisposition, as well as participation of environmental factors, such and UV light exposure. In this regard, we investigated whether polymorphisms in STK17A, a DNA repair related gene, encoding for serine/threonine-protein kinase 17A, are associated with SLE susceptibility. A total of 143 SLE patients and 177 healthy controls from Southern Brazil were genotyped for five STK17A TagSNPs. Our results indicated association of rs7805969 SNP (A and G/A genotype, OR = 1.40 and OR = 1.73, respectively) with SLE predisposition and the following clinical manifestations: arthritis, cutaneous and immunological alterations. When analyzing haplotypes distribution, we found association between TGGTC, TAGTC and AAGAT haplotypes and risk to develop SLE. When considering clinical manifestations, the haplotypes TGGTT and TAGTC were associated with protection against cutaneous alterations and the haplotype TAGTC to hematological alterations. We also observed association between SLE clinical manifestations and ethnicity, with the European-derived patients being more susceptible to cutaneous and hematological alterations

FYB gene polymorphisms are associated with susceptibility for Systemic Lupus Erythemathosus (SLE)

Systemic Lupus Erythematosus (SLE) is a multifactorial autoimmune disease affecting different organs or systems. Several genes have been associated with SLE susceptibility so far. A previous study has reported, in SLE patients, a differential expression of Fyn Binding Protein gene (FYB), encoding for a protein participating in the T cells signaling cascade and in the interleukin-2A expression modulation. This study investigates the association of 10 FYB SNPs with differential susceptibility to SLE in 143 SLE patients and 184 controls from Southern Brazil. Significant differences were observed when comparing allele and genotype frequencies distribution in patients and controls: the T allele for rs6863066 C>T SNP and C for rs358501 T>C SNP were significantly more frequent in SLE patients than in controls (p=0.0002 and p=0.008) and associated with an increased risk for SLE (OR=1.93 and OR=1.69). The frequencies of rs6863066 C/T and T/T and rs358501 C/C genotypes were significantly higher in patients than in controls (p=0.001, p=0.006 and p=0.008). A significant association was also found for the rs6863066-rs358501 T-T and T-C haplotypes (OR=2.06, p=0.002 and OR=2.93, p=0.001). When considering clinical and laboratorial manifestations, an association was found between rs2161612 G allele and G/G genotype and hematological alterations (p=0.008) and rs379707 A/C genotype and anti-dsDNA (p=0.01). In conclusion, our findings indicate an association between polymorphisms located in FYB gene and SLE, suggesting their possible involvement in disease susceptibility and clinical manifestations