Double-stranded RNA induces S100 gene expression by a cycloheximide-sensitive factor.

Viral double-stranded RNA (dsRNA) and its synthetic analog polyI:C are recognized via multiple pathways and induce the expression of genes related to inflammation. In the present study, we demonstrated the polyI:C-induced gene expression of the damage associated molecular pattern (DAMP) molecules S100A8 and S100A9, while other S100 genes were not affected. Cycloheximide and Brefeldin A treatment revealed both the expression of S100A8 and S100A9 as secondary response genes and the involvement of polyI:C-induced cytokines herein. Several type I and type III interferons such as IFNß, IL-20, IL-24, and IFNλ/IL-29 were expressed in response to polyI:C, however, they failed to induce S100A8 and S100A9 gene expression. These data indicate the involvement of the danger molecule S100A8/A9 in the resistance against viruses.

Typha latifolia L. fruit polysaccharides induce the differentiation and stimulate the proliferation of human keratinocytes in vitro.

ETHNOPHARMACOLOGICAL RELEVANCE: In Northern America Typha latifolia L. (Typhaceae) fruits are used for more than 4000 years for treatment of skin disorders, burns and as wound dressing to absorb the ichors. AIM OF THE STUDY: The following studies attempted to characterize water-soluble polysaccharides from aqueous Typha latifolia extracts and to investigate the influence of the polymers on cell physiology of human dermal fibroblasts (NHDF) and epidermal keratinocytes (NHEK). MATERIALS AND METHODS: Water-soluble raw polysaccharides (RPS) were isolated from Typha latifolia fruits and fractionated by anion exchange chromatography (AEC) and size exclusion chromatography (GPC). Fractions obtained were characterized concerning monosaccharide composition by HPAEC-PAD. The bioactivity of the polysaccharides was investigated on cell viability, proliferation, differentiation and gene expression NHDF of NHEK. RESULTS: RPS was fractionated into 5 heterodisperse fractions (TL1-TL5). The polysaccharides were composed mainly of glucose (more than 50% in RPS and TL4), galactose, xylose, mannose, glucuronic acid, galacturonic acid, arabinose, ribose, fucose, rhamnose, and fructose with differing amounts concerning to RPS and AEC-fractions. Proteins were detected in the RPS (10%) and to a less extend in TL1-TL3 (1-3%). TL1-TL3 significantly increased the proliferation of keratinocytes, whereas TL4 was shown to be a potent inductor of the early differentiation process of keratinocytes. Gene expression analysis supported these results since Smad3 and PKC-α, known to be part of signal pathways leading to cell differentiation, were significantly up regulated. Effects on fibroblasts were not observed, indicating cell specific activity of the polysaccharides. CONCLUSION: The results clearly indicate a rationale for the traditional use of Typha latifolia fruits extracts for wound healing to the strong stimulatory activity of the polysaccharides on keratinocytes proliferation and early differentiation, major activities necessary for potent wound-healing agents.

Double-stranded RNA induces MMP-9 gene expression in HaCaT keratinocytes by tumor necrosis factor-α.

Viral double-stranded RNA (dsRNA) and its synthetic analog poly (I:C) are recognized via multiple pathways and induce the expression of genes related to inflammation. In the present study, we demonstrate that poly (I:C) specifically induced the expression of matrix metallo-proteinase-9 (MMP-9) in HaCaT keratinocytes. Studies using specific pharmacological inhibitors revealed the involvement of NF-κB, p38 MAPK, and PI-3K signal transduction pathways in poly (I:C)-induced MMP-9 gene expression. MMP-9 gene induction was sensitive toward treatment with the macrolide antibiotic bafilomycin A1, a vacuolar H(+)-ATPase inhibitor, and with the lysosomotropic agent chloroquine. However, cycloheximide treatment only partially blocked poly (I:C)-induced MMP-9 gene expression. Although HaCaT keratinocytes produce a number of cytokines and chemokines in response to poly (I:C), stimulation experiments revealed that exclusively TNFα strongly promoted MMP-9 gene expression. During the antiviral response MMP-9 expression may be of importance for the tissue injury phase.

Proanthocyanidin-enriched extract from Myrothamnus flabellifolia Welw. exerts antiviral activity against herpes simplex virus type 1 by inhibition of viral adsorption and penetration.

AIM OF THE STUDY: Extracts from the aerial parts of the South African resurrection plant Myrothamnus flabellifolia Welw. have been used traditionally against infections of the upper respiratory tract and skin diseases. A polyphenol-enriched extract was investigated for potential antiviral effects against herpes simplex virus type 1 (HSV-1) and adenovirus, and the underlying mode of action was to be studied. MATERIALS AND METHODS: Antiviral effects of an acetone-water extract (MF) from Myrothamnus flabellifolia on HSV-1 and adenovirus type 3 were tested in infected Vero cells by plaque reduction assay, MTT test and immunofluorescence. The influence of the extract on the HSV-1 envelope glycoprotein D was shown by Western blot. Organotypic full thickness skin models consisting of multilayer skin equivalents were used for the investigation of MF effects on HSV-1 replication. RESULTS: MF exhibited strong antiviral activity against HSV-1. The HSV-1-specific inhibitory concentration (IC(50)) was determined as 0.4 µg/mL and the cytotoxic concentration (CC(50)) against Vero cells as 50 µg/mL. A selectivity index (SI) (ratio of CC(50) to IC(50)) of approximately 120 was calculated when MF was added to the virus inoculum for 1h at 37°C prior to infection. The replication of adenovirus 3 was not affected by MF. MF abolished virus entry into the host cell by blocking viral attachment to the cell surface. When added after attachment at a concentration of >6 µg/mL, the extract also inhibited penetration of HSV-1 into the host cell. Polyphenolic compounds from MF directly interacted with viral particles, leading to the oligomerisation of envelope proteins as demonstrated for the essential viral glycoprotein D (gD). Using organotypic full thickness tissue cultures, it was shown that treatment of HSV-1 infected cultures with the MF resulted in reduced viral spread. CONCLUSIONS: A polyphenol-enriched extract from Myrothamnus flabellifolia strongly acts against HSV-1 by blocking viral entry into the cells.

Inhibition of viral adsorption and penetration by an aqueous extract from Rhododendron ferrugineum L. as antiviral principle against herpes simplex virus type-1.

The polyphenol-enriched aqueous extract RF from the aerial parts of Rhododendron ferrugineum exhibited strong antiviral activity against herpes simplex virus type-1 while adenovirus 3 was not affected. RF exhibited an IC(50) of 7.4 µg/mL and a selectivity index of 64 when added to the virus inoculum prior to infection. RF abolished virus entry into the host cell by blocking attachment to the cell surface. When added after attachment at a concentration of >25 µg/mL, RF inhibited also penetration of HSV-1 into the host cell. RF directly interacts with viral envelope proteins as demonstrated for the viral glycoprotein gD.

Oligomeric proanthocyanidins from Rumex acetosa L. inhibit the attachment of herpes simplex virus type-1.

The polyphenole-enriched acetone-water extract R2 from the aerial parts of Rumex acetosa L. containing high amounts of oligomeric and polymeric proanthocyanidins and flavonoids was tested for antiviral activity. R2 exhibited strong antiviral activity against herpes simplex virus type-1 (HSV-1) while the replication of adenovirus 3 was not affected. By plaque reduction test and MTT assay on Vero cells, the HSV-1-specific inhibitory concentration (IC(50)) and cytotoxic concentration (CC(50)) were determined. R2 exibited an IC(50) of 0.8 µg/mL and a selectivity index (SI) (ratio of IC(50) to CC(50)) of approximately 100 when added to the virus inoculum for 1h at 37°C prior to infection. The antiviral activity was due to the presence of flavan-3-ols and oligomeric proanthocyanidins in the extract. Structure-activity analyses indicated that flavan-3-ols and proanthocyanidins with galloylation at position O-3 are highly potent compounds (SI>40), while ungalloylated compounds did not exhibit antiviral effects (SI<1). R2 and a major proanthocyanidin from R2, epicatechin-3-O-gallate-(4ß→8)-epicatechin-3-O-gallate abolished virus entry into the host cell by blocking attachment to the cell surface. When added after attachment at a concentration of ≥ 12.5 µg/mL, R2 inhibited also penetration of HSV-1 into the host cell. R2 and epicatechin-3-O-gallate-(4ß→8)-epicatechin-3-O-gallate were shown to directly interact with viral particles leading to the oligomerisation of envelope proteins as demonstrated for the essential viral glycoprotein gD. Using raft cultures with three-dimensional organotypic human skin equivalents it was shown that treatment of cultures with R2 after infection with HSV-1 resulted in a reduced viral spread.