Background: A critical issue with nanomaterials is the clear understanding of their potential toxicity. We evaluated the toxic effect of 24 nanoparticles of similar equivalent spherical diameter and various elemental compositions on 2 human pulmonary cell lines: A549 and THP-1. A secondary aim was to elaborate a generic experimental set-up that would allow the rapid screening of cytotoxic effect of nanoparticles. We therefore compared 2 cytotoxicity assays (MTT and Neutral Red) and analyzed 2 time points (3 and 24 hours) for each cell type and nanoparticle. When possible, TC50 (Toxic Concentration 50 i.e. nanoparticle concentration inducing 50% cell mortality) was calculated.

HIV (human immunodeficiency virus) diverts the cellular ESCRT (endosomal sorting complex required for transport) machinery to promote virion release from infected cells. The ESCRT consists of four heteromeric complexes (ESCRT-0 to ESCRT-III), which mediate different membrane abscission processes, most importantly formation of intralumenal vesicles at multivesicular bodies. The ATPase VPS4 (vacuolar protein sorting 4) acts at a late stage of ESCRT function, providing energy for ESCRT dissociation. Recruitment of ESCRT by late-domain motifs in the viral Gag polyprotein and a role of ESCRT in HIV release are firmly established, but the order of events, their kinetics and the mechanism of action of individual ESCRT components in HIV budding are unclear at present. Using live-cell imaging, we show late-domain-dependent recruitment of VPS4A to nascent HIV particles at the host cell plasma membrane. Recruitment of VPS4A was transient, resulting in a single or a few bursts of at least two to five VPS4 dodecamers assembling at HIV budding sites. Bursts lasted for ∼35 s and appeared with variable delay before particle release. These results indicate that VPS4A has a direct role in membrane scission leading to HIV-1 release.

Bullous pemphigoid (BP) is an autoimmune skin disease characterized by the binding of autoantibodies to components of the hemidesmosome structure resulting in an inflammatory response and subepidermal blister formation. To investigate the role of immune orientation in the inflammatory processes associated to disease progression, blister fluid, serum and biopsy specimens were collected from thirty one consecutive BP patients. Blister fluids displayed high level of IL-6, IL-17, IL-22, IL-23, whereas TGF-β was increased in BP sera. However neither immunocytochemistry on a trans-differentiation model of IL-17-producing PBMCs nor immunohistochemistry on BP biopsy specimens could demonstrate the presence of Th17 lymphocytes. Instead innate immune cells, especially neutrophils, produced IL-17 at the skin lesional site. Of note, superpotent topical corticosteroid application quickly and dramatically reduced both IL-17 expression and clinical signs of BP. Consistently, IL-17 upregulated MMP-9 and neutrophil elastase expression, two proteases involved in blister formation, thereof further demonstrating its role in the progress of BP. Finally IL-17-induced matrix degradation originated from neutrophil activation, initiated the formation of an amplification loop of the inflammatory response that could represent the underlying phenomenon leading to the maintenance and even disease extent. Thus, our results could open new therapeutic strategies for BP patients.