Virus-host interactions during hepatitis C virus entry — implications for pathogenesis and novel treatment approaches

Hepatitis C virus (HCV) is a member of the Flaviviridae family and causes acute and chronic hepatitis. Chronic HCV infection may result in severe liver damage including liver cirrhosis and hepatocellular carcinoma. The liver is the primary target organ of HCV, and the hepatocyte is its primary target cell. Attachment of the virus to the cell surface followed by viral entry is the first step in a cascade of interactions between the virus and the target cell that is required for successful entry into the cell and initiation of infection. This step is an important determinant of tissue tropism and pathogenesis; it thus represents a major target for antiviral host cell responses, such as antibody-mediated virus neutralization. Following the development of novel cell culture models for HCV infection our understanding of the HCV entry process and mechanisms of virus neutralization has been markedly advanced. In this review we summarize recent developments in the molecular biology of viral entry and its impact on pathogenesis of HCV infection, development of novel preventive and therapeutic antiviral strategies.      

Prolonged root hypoxia induces ammonium accumulation and decreases the nutritional quality of tomato fruits

Here we examined the effects of root hypoxia (1-2% oxygen) on the physiology of the plant and on the biochemical composition of fruits in tomato (Solanum lycopersicum cv. Micro-Tom) plants submitted to gradual root hypoxia at first flower anthesis. Root hypoxia enhanced nitrate absorption with a concomitant release of nitrite and ammonium into the medium, a reduction of leaf photosynthetic activity and chlorophyll content, and an acceleration of fruit maturation, but did not affect final fruit size. Quantitative metabolic profiling of mature pericarp extracts by (1)H NMR showed that levels of major metabolites including sugars, organic acids and amino acids were not modified. However, ammonium concentration increased dramatically in fruit flesh, and ascorbate and lycopene concentrations decreased. Our data indicate that the unfavorable effects of root hypoxia on fruit quality cannot be explained by two of the well-known effects of root hypoxia on the plant, namely a decrease in photosynthesis or an excess in ethylene production, but may instead result from disturbances in the supply of either growth regulators or ammonium, by the roots.     

Hsc70 regulates cell surface ASIC2 expression and vascular smooth muscle cell migration

Recent studies suggest members of the degenerin (DEG)/epithelial Na(+) channel (ENaC)/acid-sensing ion channel (ASIC) protein family play an important role in vascular smooth muscle cell (VSMC) migration. In a previous investigation, we found suppression of a certain DEG/ENaC/ASIC member, ASIC2, increased VSMC chemotactic migration, raising the possibility that ASIC2 may play an inhibitory role. Because ASIC2 protein was retained in the cytoplasm, we reasoned increasing surface expression of ASIC2 might unmask the inhibitory role of ASIC2 in VSMC migration so we could test the hypothesis that ASIC2 inhibits VSMC migration. Therefore, we used the chemical chaperone glycerol to enhance ASIC2 expression. Glycerol 1) increased cytoplasm ASIC2 expression, 2) permitted detection of ASIC2 at the cell surface, and 3) inhibited platelet-derived growth factor (PDGF)-bb mediated VSMC migration. Furthermore, ASIC2 silencing completely abolished the inhibitory effect of glycerol on migration, suggesting upregulation of ASIC2 is responsible for glycerol-induced inhibition of VSMC migration. Because other investigators have shown that glycerol regulates ENaC/ASIC via interactions with a certain heat shock protein, heat shock protein 70 (Hsc70), we wanted to determine the importance of Hsc70 on ASIC2 expression in VSMCs. We found that Hsc70 silencing increases ASIC2 cell surface expression and inhibits VSMC migration, which is abolished by cosilencing ASIC2. These data demonstrate that Hsc70 inhibits ASIC2 expression, and, when the inhibitory effect of Hsc70 is removed, ASIC2 expression increases, resulting in reduced VSMC migration. Because VSMC migration contributes to vasculogenesis and remodeling following vascular injury, our findings raise the possibility that ASIC2-Hsc70 interactions may play a role in these processes.     

Fine needle aspiration in aspergilloma of frontal sinus: a case report

BACKGROUND: The increased incidence of fungal diseases in humans is most likely due to indiscriminate use of broad-spectrum antibiotics and increased numbers of immunocompromised patients. Although Aspergillus species are ubiquitous and normally nonpathogenic, they can be opportunistic pathogens in immunocompromised individuals. CASE: A 22-year-old immunocompetent man presented with a gradually increasing subcutaneous swelling near the root of his nose for previous 6 months. The mass was soft to firm, solid, nontender and immobile. There was no superficial skin ulceration and no local signs of inflammation. Proptosis of the left eye was present without any visual impairment. An osteolytic lesion that was contiguous with the subcutaneous mass, with the opacities of both the fontal sinuses was observed radiographically. Fine needle aspiration cytology (FNAC) demonstrated presence of branching hyphae in the cytoplasm of multinucleated giant cells along with mixed inflammatory cells. The species was identified by culture in Sabouraud's agar with chloramphenicol and wet mount with lactophenol cotton blue stain. CONCLUSION: Aspergillosis can remain dormant over a long period. Although uncommon, it can occur in immunocompetent patients. FNA is a very useful tool in establishing the diagnosis     

Cloning,Expression, and Assessment of Cytotoxic Effects of A-NGR Fusion Protein

Targeted drug delivery is an attractive field in cancer studies. In this study, a novel fusion protein consisting of Shiga toxin A subunit and NGR peptide has been constructed. The cytotoxic Shiga toxin A subunit has the ability to kill cancer cells while NGR is a well-known peptide that targets the whole molecule to cancer cells. Two forms of this novel fusion protein, one without linker (A-NGR) and one with linker (A-GGGGS-NGR) were studied. 3D structure prediction of the two forms carried out by I-TASSER and their validation and analysis were performed by ProSA web and RAMPAGE. Results showed that A-NGR is a better model than the one with linker. A-NGR was constructed by PCR method and cloned in pBAD/gIII A vector. Then, it was successfully expressed in Escherichia coli by induction with arabinose and subsequently purified by affinity chromatography under denaturing condition. Ultimately, the cytotoxic effect of the purified protein was evaluated on U937 cancer cells and MRC-5 normal cells by MTT assay. Conclusively, the fusion protein was successfully cloned and expressed and evaluated for its cytotoxic effects. The IC50 value of A-NGR fusion protein for U937 cell was about 26.86 µg/ml while no cytotoxic effect was observed on MRC-5 cells. Therefore, considering the promising cytotoxic effects of the fusion protein, further in vitro evaluations of this fusion protein on different cell lines are underway.     

Regulation of autophagy by polyphenols: Paving the road for treatment of neurodegeneration

In the present paper, we will discuss on the importance of autophagy in the central nervous system, and outline the relation between autophagic pathways and the pathogenesis of neurodegenerative disorders. The potential therapeutic benefits of naturally occurring phytochemicals as pharmacological modulators of autophagy will also be addressed. Our findings provide renewed insight on the molecular modes of protection by polyphenols, which is likely to be at least in part mediated not only by their potent antioxidant and anti-inflammatory effects, but also through modulation of autophagic processes to remove the aberrant protein aggregates.     

Polarization‐multiplexed,dual‐beam swept source optical coherence tomography angiography

A polarization‐multiplexed, dual‐beam setup is proposed to expand the field of view (FOV) for a swept source optical coherence tomography angiography (OCTA) system. This method used a Wollaston prism to split sample path light into 2 orthogonal‐polarized beams. This allowed 2 beams to shine on the cornea at an angle separation of ~14°, which led to a separation of ~4.2 mm on the retina. A 3‐mm glass plate was inserted into one of the beam paths to set a constant path length difference between the 2 polarized beams so the interferogram from the 2 beams are coded at different frequency bands. The resulting OCTA images from the 2 beams were coded with a depth separation of ~2 mm. A total of 5 × 5 mm² angiograms from the 2 beams were obtained simultaneously in 4 seconds. The 2 angiograms then were montaged to get a wider FOV of ~5 × 9.2 mm².      

Gold and Female Reproductive Organs: an Ultrastructural Study

Gold, a heavy yellow-colored metal, is usually found in nature as a metallic element or as salts. This noble metal historically had a reputation as an anti-inflammatory medicine for rheumatoid arthritis, a nervine, and a remedy for nervous disorders, as well as a potential anticancer agent. It has also been used as component in dental restorations and in implant materials. The present study was undertaken to point out histological and ultrastructural effects of gold, administered by intraperitoneal route, in pregnant female reproductive organs (ovary and uterus), in order to clarify its side effects on the reproductive function. Using the transmission electron microscopy (TEM), the ultrastructural investigations of both ultrathin ovarian and uterine sections of treated pregnant rats revealed the existence of numerous heterogeneous clusters with very electron-dense inclusions characterized by various aspects in the lysosomes of granulosa, theca interna cells, and theca externa cells. Degeneration of these tissues, like cell vacuolization, marked expansion of the endoplasmic reticulum, mitochondrial alterations, and necrotic foci, were also highlighted. Moreover, huge phagolysosomes and high numbers of eosinophils as signs of inflammation were also identified especially in endometrial and myometrial cells of gold-treated rats. The ultrastructural investigations of reproductive organ sections of control pregnant rats showed a normal ultrastructural aspect and no loaded lysosomes. These results speculated the toxicity of gold at the used dose. The observed signs of toxicity allowed concluding that the important role of lysosome in the sequestration of this element under an insoluble form in all categories of cells in the studied tissues does not seem to be efficient.     

Production of TNFα and IL-6 by Activated Whole Blood from HIV-1 Infected Patients Detected by a One-Stage Procedure: Relationship with the Phenotype of HIV-1 Isolates

Diluted whole blood (WB) culturing may be the most appropriate milieu in which to study cytokine production in vitro. We tested TNFα and IL-6 production using small volumes of WB (25 μl) from HIV-1 positive patients with a one-step procedure that combines WB stimulation with LPS, PHA and cytokine measurement. We studied 49 patients without secondary infection or at distance of secondary infection staged according to the 1993 classification of the CDC and 12 healthy seronegative subjects. Heparinized blood from 5 control subjects had been collected sequentially during a period of 5 months. The individual variations of TNFα and IL-6 production were limited for all these individuals. In 1 out of 20 CDC group A patients, 6 out of 17 CDC group B patients and 3 out of 12 CDC group C patients, we obtained higher values of TNFα than the mean + 2 S.D. of the control group. In 3 out of 20 CDC group A patients, 1 out of 17 CDC group B patients without AIDS and 5 out of 12 CDC group C patients, the TNFα values were lower than the mean ?2 S.D. of the control group. Low IL-6 values were obtained in 1 out of 20 CDC group A patients and 1 out of 17 CDC group B patients and 3 out of 12 CDC group C patients. There was no correlation between TNFα production in vitro and plasma level of TNFα. We found no correlation between the levels of cytokines and monocyte count or between the levels of cytokines and CD4 T-cell count in peripheral blood. Our data point out a disarray in TNFα and IL-6 production by WB from HIV-1 infected patients. The relationship between the disarray of cytokine production and cytopathogenicity of HIV-1 isolates in the P4 cell line was investigated in this study. We found a correlation between the high level of TNFα produced by WB and the phenotype of HIV-1 isolates isolated from patients. The one-stage procedure used in this work is of potential value to investigate the activation status of cells for monitoring HIV-1 positive individuals and predicting HIV-1 phenotype.