Corrigendum: Intracellular Delivery: Exploiting Viral Membrane Topic Peptide.

The authors declare that after the publication of the article, it was noticed that two citations were inadvertently omitted. The references have now been included as [74b] and [74c]: [74] (b) Vitiello, M.; Galdiero, M.; Galdiero, M. Inhibition of Viral-Induced Membrane Fusion by Peptides. Protein Pep. Lett., 2009, 16(7), 786-793. (c) Galdiero, S.; Falanga, A.; Vitiello, M.; D'Isanto, M.; Cantisani, M.; Kampanaraki, A.; Benedetti, E.; Browne, H.; Galdiero, M. Peptides containing membrane-interacting motifs inhibit herpes simplex virus type 1 infectivity. Peptides, 2008, 29(9), 1461- 1471. The authors would like to include this reference in the online version of the article to ensure completeness.

Antiviral activity of mycosynthesized silver nanoparticles against herpes simplex virus and human parainfluenza virus type 3.

The interaction between silver nanoparticles and viruses is attracting great interest due to the potential antiviral activity of these particles, and is the subject of much research effort in the treatment of infectious diseases. In this work, we demonstrate that silver nanoparticles undergo a size-dependent interaction with herpes simplex virus types 1 and 2 and with human parainfluenza virus type 3. We show that production of silver nanoparticles from different fungi is feasible, and their antiviral activity is dependent on the production system used. Silver nanoparticles are capable of reducing viral infectivity, probably by blocking interaction of the virus with the cell, which might depend on the size and zeta potential of the silver nanoparticles. Smaller-sized nanoparticles were able to inhibit the infectivity of the viruses analyzed.

Conformational modifications of gB from herpes simplex virus type 1 analyzed by synthetic peptides.

Entry of enveloped viruses requires fusion of viral and cellular membranes, driven by conformational changes of viral glycoproteins. The crystallized trimeric glycoprotein gB of herpes simplex virus has been described as a postfusion conformation, and several studies prove that like other class III fusion proteins, gB undergoes a pH-dependent switch between the pre- and postfusion conformations. Using several biophysical techniques, we show that peptides corresponding to the long helix of the gB postfusion structure interfere with the membrane fusion event, likely hampering the conformational rearrangements from the pre- to the postfusion structures. Those peptides represent good candidates for further design of peptidomimetic antagonists capable of blocking the fusion process.

Intracellular delivery: exploiting viral membranotropic peptides.

Recent advances in the understanding of cellular and molecular mechanisms of the pathogenesis of several diseases offer the possibility to address novel molecular targets for an improved diagnosis and therapy. In fact, in order to fulfill their function, macromolecular drugs, reporter molecules, and imaging agents often require to be delivered into specific intracellular compartments, usually the cytoplasm or the nucleus. From a medical perspective, biological membranes represent a critical hindrance due to their barrier-like behaviour not easily circumvented by many pharmacologically-active molecules. Therefore, identifying strategies for membrane translocation is essential. Several technologies have been designed to improve cellular uptake of therapeutic molecules, including cell-penetrating peptides (CPPs). These peptides, which are able to efficiently translocate macromolecules through the plasma membrane, have attracted a lot of attention, and new translocating peptides are continuously described. In this review, we will focus on the viral derived peptides, and in particular those derived by viral entry proteins that may be useful as delivery vehicles due to their intrinsic properties of inducing membrane perturbation.

P2 porin and loop L7 from Haemophilus influenzae modulate expression of IL-6 and adhesion molecules in astrocytes.

During neuropathological conditions such as infections and degenerative diseases, astrocytes can be activated by infiltrating immune cells. Activated astrocytes can produce chemokines, cytokines and adhesion molecules. In this study, the production of IL-6 and adhesion molecules intercellular adhesion molecule-1 (ICAM-1), vascular cellular adhesion molecule-1 (VCAM-1) and E-selectin by human astroglioma cells stimulated with Gram-negative surface components was investigated. Haemophilus influenzae type b porin P2 and its selected active peptide, loop L7, were found to induce MEK1-MEK2/ mitogen-activated protein kinase phosphorylation in U87-MG cells as demonstrated by ELISA, and up-regulate cellular adhesion molecule and interleukin-6 (IL-6) production as shown by RT-PCR and ELISA. Using two potent and selective inhibitors of MEK activation by Raf-1 (PD-098059) and p38 (SB-203580), it was also demonstrated that both ERK1/2 and p38 pathways play key roles in the production of IL-6 as well as in ICAM-1, VCAM-1 and E-selectin expression by Hib porin.