CD155 on HIV-infected cells is not modulated by HIV-1 Vpu and Nef but synergizes with NKG2D ligands to trigger NK cell lysis of autologous primary HIV-infected cells

Activation of primary CD4(+) T cells induces the CD155, but not the CD112 ligands for the natural killer (NK) cell activation receptor (aNKR) CD226 [DNAX accessory molecule-1 (DNAM-1)]. We hypothesize that HIV productively infects activated CD4(+) T cells and makes itself vulnerable to NK cell-mediated lysis when CD155 on infected T cells engages DNAM-1. The primary objective of this study is to determine whether CD155 alone or together with NKG2D ligands triggers autologous NK cell lysis of HIV-infected T cells and whether HIV modulates CD155. To determine whether HIV modulates this activation ligand, we infected “activated” CD4(+) T cells with HIV in the absence or presence of Nef and/or Vpu and determined by flow cytometry whether they modulated CD155. To determine if CD155 alone, or together with NKG2D ligands, triggered NK cell lysis of autologous HIV-infected T cells, we treated purified NK cells with DNAM-1 and/or NKG2D blocking antibodies before the addition of purified autologous HIV-infected cells in cytolytic assays. Finally, we determined whether DNAM-1 works together with NKG2D as an NK cell coactivation receptor (caNKR) or whether they work independently as aNKRs to induce an NK cell lytic response. We demonstrate that HIV and specifically Nef and/or Vpu do not modulate CD155 on infected primary T cells; and both CD155 and NKG2D ligands synergize as aNKRs to trigger NK cell lysis of the infected cell

Endocytic uptake, transport and macromolecular interactions of anionic PAMAM dendrimers within lung tissue

Purpose: Polyamidoamine (PAMAM) dendrimers are a promising class of nanocarrier with applications in both small and large molecule drug delivery. Here we report a comprehensive evaluation of the uptake and transport pathways that contribute to the lung disposition of dendrimers. Methods: Anionic PAMAM dendrimers and control dextran probes were applied to an isolated perfused rat lung (IPRL) model and lung epithelial monolayers. Endocytosis pathways were examined in primary alveolar epithelial cultures by confocal microscopy. Molecular interactions of dendrimers with protein and lipid lung fluid components were studied using small angle neutron scattering (SANS). Results: Dendrimers were absorbed across the intact lung via a passive, size-dependent transport pathway at rates slower than dextrans of similar molecular sizes. SANS investigations of concentration-dependent PAMAM transport in the IPRL confirmed no aggregation of PAMAMs with either albumin or dipalmitoylphosphatidylcholine lung lining fluid components. Distinct endocytic compartments were identified within primary alveolar epithelial cells and their functionality in the rapid uptake of fluorescent dendrimers and model macromolecular probes was confirmed by co-localisation studies. Conclusions: PAMAM dendrimers display favourable lung biocompatibility but modest lung to blood absorption kinetics. These data support the investigation of dendrimer-based carriers for controlled-release drug delivery to the deep lung

Imogolite: An Aluminosilicate Nanotube Endowed with Low Cytotoxicity and Genotoxicity

High-aspect-ratio nanomaterials (HARN) (typically, single-walled carbon nanotubes (SWCNT) or multiwalled carbon nanotubes (MWCNT)) impair airway barrier function and are toxic to macrophages. Here, we assess the biological effects of nanotubes of imogolite (INT), a hydrated aluminosilicate [(OH)3Al2O3SiOH] occurring as single-walled NT, on murine macrophages and human airway epithelial cells. Cell viability was assessed with resazurin. RT-PCR was used to study the expression of Nos2 and Arg1, markers of classical or alternative macrophage activation, respectively, and nitrite concentration in the medium was determined to assess NO production. Epithelial barrier integrity was evaluated from the trans-epithelial electrical resistance (TEER). Potential genotoxicity of INT was assessed with comet and cytokinesis-block micronucleus cytome assays. Compared to MWCNT and SWCNT, INT caused much smaller effects on RAW264.7 and MH-S macrophage viability. The incubation of macrophages with INT at doses as high as 120 μg/cm2 for 72 h did not alter either Nos2 or Arg1 expression nor did it increase NO production, whereas IL6 was induced in RAW264.7 cells but not in MH-S cells. INT did not show any genotoxic effect in RAW264.7 and A549 cells except for a decrease in DNA integrity observed in epithelial A549 cells after treatment with the highest dose (80 μg/cm2). No significant change in permeability was recorded in Calu-3 epithelial cell monolayers exposed to INT, whereas comparable doses of both SWCNT and MWCNT lowered TEER. Thus, in spite of their fibrous nature, INT appear not to be markedly toxic for in vitro models of lung−blood barrier cell

Emerging Nanotechnology in Chronic Respiratory Diseases

A large population, including people of all age groups, is suffering from chronic respiratory diseases worldwide. Asthma, chronic obstructive pulmonary disease, occupational lung diseases, cystic fibrosis, etc. are the most common of these diseases and are noncurable with conventional and currently available therapies. Nanotechnology is emerging as a great therapeutic promise in different spheres including drug delivery systems and is becoming the technology of choice nowadays. The administration of drugs via inhalation helps in avoiding the first-pass metabolism by targeted delivery to the affected site. It has been observed that there is a huge diversity in nanotechnology being used in pulmonary diseases, and thus safety assessment is a challenging as well as important task. The present review focuses on some of the major emerging nanotechnologies for chronic pulmonary diseases and includes some of the latest studies in the field of nanomedicines