Effect of cigarette smoke on mucosal vaccine response with activation of plasmacytoid dendritic cells: The outcomes of in vivo and in vitro experiments.

Mucosal vaccines offer several advantages over transdermal vaccines, including the ability to acquire systemic and mucosal immunities. Smoking is a huge public health threat and major risk factor for various diseases that exacerbate or prolong respiratory symptoms and conditions. However, its impact on the efficacy of mucosal vaccines remains partially explored. Thus, this study investigates the effects of smoking on mucosal vaccine reactivity by assessing the induction of Th1 immunity, a vital response in infection defense. Cigarette smoke condensate was prepared as a substitute for mainstream smoke. We intranasally administered diphtheria toxoid as an antigen and natural CpG oligonucleotide G9.1, which enhances the Th1-type antibody (Ab) response in a plasmacytoid dendritic cells (pDCs) dependent manner, as an adjuvant to mice to assess the effect of cigarette smoke condensate on Ab responses. The mechanism of its effect was evaluated using human peripheral blood mononuclear cells and their pDC-rich fraction cultured with or without G9.1. In mice, cigarette smoke condensate tended to decrease diphtheria toxoid-specific Ab response, with a higher reduction in Th1-type IgG2 Ab response than in Th2-type IgG1 Ab response. In human peripheral blood mononuclear cells, cigarette smoke condensate significantly reduced the induction of IFN-α production by G9.1. Moreover, G9.1-induced increases in the CD83 expression in pDCs and the CD80 expression in DCs were suppressed via treatment with cigarette smoke condensate. Among the mechanisms suggested were decreased expression of toll-like receptor 9 mRNA, decreased expression of mRNA for IFN regulatory factor 7, and increased CpG methylation of its promoter region. The analysis of Tbet and GATA3 expressions revealed that cigarette smoke condensate exhibits Th1-directed immunostimulatory activity at a steady state but becomes more Th2-directed under G9.1 stimulation. In conclusion, smoking could reduce mucosal vaccine responses by decreasing pDC activation and, consequently, Th1-dominant immunity.

Two-step photomechanical motion of a dibenzobarrelene crystal.

Photomechanical crystals are interesting from both basic and applied perspectives, and thus it is important to develop new examples. We investigated the photomechanical bending behaviour of a photochromic crystal of a dibenzobarrelene derivative. When a plate-like crystal was irradiated with ultraviolet (UV) light at 365 nm, two-step bending was observed. In the first step, the crystal quickly bent away from the light source, with an accompanying crystal colour change from colourless to purple. In the second step, under prolonged UV light, the bending returned slowly and then the crystal bent up towards the opposite direction, accompanied by an additional colour change to light yellow. Spectroscopic measurements and X-ray crystallographic analysis suggested that a long-lived biradical species is generated immediately upon UV light irradiation via a Norrish type II intramolecular hydrogen abstraction, and then the final photoproducts are formed under continuous UV exposure. X-ray crystallographic analysis before and after UV light irradiation for a few seconds revealed that the longitudinal axis (a axis) of the crystal elongated slightly after irradiation, which is consistent with the direction of the first-step bending. Based on these results, we propose that first-step bending could be induced by a biradical species, generated via a Norrish type II intramolecular hydrogen abstraction, and the second-step bending could originate from the formation of a mixture of final photoproducts under prolonged light irradiation.

Hyperoxia causes diffuse alveolar damage through mechanisms involving upregulation of c-Myc/Bax and enhanced production of reactive oxygen species.

BACKGROUND: Hyperoxia is a known cause of diffuse alveolar damage (DAD). We previously reported the transcript profiling of DAD induced by hyperoxia exposure in mouse lungs and showed that the gene expression of myelocytomatosis oncogene (c-Myc) was significantly upregulated whereas that of surfactant-associated protein (SP)-C was downregulated. However, the mechanism underlying hyperoxia-induced DAD is not well understood. METHODS: The hyperoxia-induced changes in SP-A/B/C/D, c-Myc, B-cell chronic lymphocytic leukemia/lymphoma (Bcl)-2, and Bcl-2-associated X protein (Bax) expression in mouse lungs were examined by cDNA microarray analysis. The expression levels of the above mentioned genes, cell viability, caspase activity, and reactive oxygen species (ROS) production were also examined in the human lung adenocarcinoma cell line A549 and mouse fibroblast-like cell line NIH/3T3. RESULTS: Hyperoxia induced a decrease in SP-C/A expression in mouse lungs, and SP-C downregulation was also confirmed in A549 cells. In addition to enhanced c-Myc expression, Bax expression also increased following exposure of the mice to hyperoxia. In vitro analysis showed that expression of these genes is regulated in a cell-type-dependent manner, i.e., upregulation of c-Myc in NIH/3T3 cells and Bax in A549 cells occurred regardless of whether there was a similar decrease in cell viability and increase in caspase-3/7 activation in response to hyperoxia. ROS production and caspase-8 activation were also observed in both cells. CONCLUSIONS: We concluded that hyperoxia induces ROS production and cell death in lung tissues through a cell-type specific mechanism involving the upregulation of c-Myc/Bax, and caspase-8 and -3/7 activation-dependent pathways, thereby leading to the development of DAD.

A palindromic CpG-containing phosphodiester oligodeoxynucleotide as a mucosal adjuvant stimulates plasmacytoid dendritic cell-mediated T(H)1 immunity.

BACKGROUND: CpG oligodeoxynucleotides (ODNs), resembling bacterial DNA, are currently tested in clinical trials as vaccine adjuvants. They have the nuclease-resistant phosphorothioate bond; the immune responses elicited differ according to the CpG ODN sequence and vaccination method. To develop a CpG ODN that can induce plasmacytoid dendritic cell (pDC)-mediated T(H)1 immunity through the mucosa, we constructed phosphodiester G9.1 comprising one palindromic CpG motif with unique polyguanosine-runs that allows degradation similar to naturally occurring bacterial DNA. METHODS: T(H)1 and T(H)2 immunity activation was evaluated by cytokine production pattern and T-bet/GATA-3 ratio in human peripheral blood mononuclear cells and mouse bone marrow cells. Adjuvanticity was evaluated in mice administered G9.1 with diphtheria toxoid (DT) through nasal vaccination. RESULTS: G9.1 exhibited stronger IFN-α-inducing activity than A-class CpG ODN2216 and increased T-bet/GATA-3 ratio by enhancing T-bet expression. Nasally administered G9.1 plus DT induced DT-specific mucosal IgA and serum IgG, but not IgE, responses with antitoxin activity in C57BL/6 and BALB/c mice, possibly due to IFN/BAFF production. Induction of T(H)1, but not T(H)2-type Abs depended completely on pDCs, the first in vivo demonstration by CpG ODNs. CONCLUSIONS: G9.1 is a promising mucosal adjuvant for induction of pDC-mediated T(H)1 immunity.

Determination of the torsion angles of alanine and glycine residues of model compounds of spider silk (AGG)(10) using solid-state NMR methods.

Spiders synthesize several kinds of silk fibers. In the primary structure of spider silk, one of the major ampullate (dragline, frame) silks, spidroin 1, and flagelliform silk (core fibers of adhesive spiral), there are common repeated X-Gly-Gly (X = Ala, Leu, Pro, Tyr, Glu, and Arg) sequences, which are considered to be related to the elastic character of these fibers. In this paper, two dimensional spin diffusion solid-state NMR under off magic angle spinning (OMAS), (13)C chemical shift contour plots, and Rotational Echo DOuble Resonance (REDOR) were applied to determine the torsion angles of one Ala and two kinds of Gly residues in the Ala-Gly-Gly sequence of (13)C=O isotope-labeled (Ala-Gly-Gly)(10). The torsion angles were determined to be (phi, psi) = (-90 degrees, 150 degrees ) within an experimental error of +/-10 degrees for each residue. This conformation is characterized as 3(1) helix which is in agreement with the structure proposed from the X-ray powder diffraction pattern of poly(Ala-Gly-Gly). The 3(1) helix of (Ala-Gly-Gly)(10) does not change by formic acid treatment although (Ala-Gly)(15) easily changes from the silk I conformation (the structure of Bombyx mori silk fibroin before spinning in the solid state) to silk II conformation (the structure of the silk fiber after spinning) by such treatment. Thus, the 3(1) helix conformation of (Ala-Gly-Gly)(10) is considered very stable. Furthermore, the torsion angles of the 16th Leu residue of (Leu-Gly-Gly)(10) were also determined as (phi, psi) = (-90 degrees, 150 degrees ) and this peptide is also considered to take 3(1) helix conformation.