Negative Regulation of Toll-like Receptor-4 Signaling through the Binding of Glycosylphosphatidylinositol-anchored Glycoprotein,CD14, with the Sialic Acid-binding Lectin,CD33

When monocyte-derived immature dendritic cells (imDCs) were stimulated with LPS in the presence of anti-CD33/Siglec-3 mAb, the production of IL-12 and phosphorylation of NF-κB decreased significantly. The cell surface proteins of imDCs were chemically cross-linked, and CD33-linked proteins were analyzed by SDS-PAGE and immunoblotting. It was CD14 that was found to be cross-linked with CD33. A proximity ligation assay also indicated that CD33 was colocalized with CD14 on the cell surface of imDCs. Sialic acid-dependent binding of CD33 to CD14 was confirmed by a plate assay using recombinant CD33 and CD14. Three types of cells (HEK293T cells expressing the LPS receptor complex (Toll-like receptor (TLR) cells), and the LPS receptor complex plus either wild-type CD33 (TLR/CD33WT cells) or mutated CD33 without sialic acid-binding activity (TLR/CD33RA cells)) were prepared, and then the binding and uptake of LPS were investigated. Although the level of LPS bound on the cell surface was similar among these cells, the uptake of LPS was reduced in TLR/CD33WT cells. A higher level of CD14-bound LPS and a lower level of TLR4-bound LPS were detected in TLR/CD33WT cells compared with the other two cell types, probably due to reduced presentation of LPS from CD14 to TLR4. Phosphorylation of NF-κB after stimulation with LPS was also compared. Wild-type CD33 but not mutated CD33 significantly reduced the phosphorylation of NF-κB. These results suggest that CD14 is an endogenous ligand for CD33 and that ligation of CD33 with CD14 modulates with the presentation of LPS from CD14 to TLR4, leading to down-regulation of TLR4-mediated signaling.     

Functional analysis of the honeybee (Apis mellifera L.) salivary system using proteomics

In insects, specific proteins and physiologically active molecules whose functions are related to their lifestyles are secreted from the salivary system. To investigate proteins/molecules related to the sociality of the European honeybee (Apis mellifera L.), we performed a proteomic analysis of the honeybee salivary system. The honeybee salivary system comprises two secretory glands: the postcerebral gland (PcG) and the thoracic gland (TG), both of which are connected to a common duct that opens in the mouthpart. Although most (31 out of 35) of the major proteins identified from the PcG and TG were housekeeping proteins, the spot intensities for aldolase and acetyl-CoA acyltransferase 2 were stronger in the PcG than in the TG in the 2-dimensional gel electrophoresis. Immunoblotting confirmed that the expression of these proteins was stronger in the PcG than in the TG, whereas expression was almost not detectable in the hypopharyngeal gland (HpG), suggesting that carbohydrate metabolism is enhanced in the honeybee PcG. In addition, imaginal disc growth factor 4 (IDGF4) was synthesized in the honeybee salivary system. Immunoblotting indicated IDGF4 expression was very strong in the PcG, moderate in the TG, and very weak in the HpG. A considerable amount of IDGF4 was detected in the royal jelly, while less was detected in honey, strongly suggesting that the honeybee salivary system secretes IDGF4 into the royal jelly and honey. The secreted IDGF4 might therefore affect growth and physiology of the other colony members.     

Metabolic engineering for the production of shikimic acid in an evolved <Emphasis Type="Italic">Escherichia coli</Emphasis> strain lacking the phosphoenolpyruvate: carbohydrate phosphotransferase system

Background  

Shikimic acid (SA) is utilized in the synthesis of oseltamivir-phosphate, an anti-influenza drug. In this work, metabolic engineering approaches were employed to produce SA in Escherichia coli strains derived from an evolved strain (PB12) lacking the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS^-) but with capacity to grow on glucose. Derivatives of PB12 strain were constructed to determine the effects of inactivating aroK, aroL, pykF or pykA and the expression of plasmid-coded genes aroG ^fbr, tktA, aroB and aroE, on SA synthesis.     

Effect of pre-composting on vermicomposting of kitchen waste

The aim of this work was to test combination of the thermocomposting and vermicomposting to improve the treatment efficiency and assess the optimum period required in each method to produce good quality compost. The results showed that pre-thermocomposting improved vermicomposting of kitchen waste. A 9-day thermocomposting prior to vermicomposting helped in mass reduction, moisture management and pathogen reduction.     

Cosegregation of asymmetric features during cell division

Cellular asymmetry plays a major role in the ageing and evolution of multicellular organisms. However, it remains unknown how the cell distinguishes ‘old’ from ‘new’ and whether asymmetry is an attribute of highly specialized cells or a feature inherent in all cells. Here, we investigate the segregation of three asymmetric features: old and new DNA, the spindle pole body (SPB, the centrosome analogue) and the old and new cell ends, using a simple unicellular eukaryote, Schizosaccharomyces pombe. To our knowledge, this is the first study exploring three asymmetric features in the same cells. We show that of the three chromosomes of S. pombe, chromosome I containing the new parental strand, preferentially segregated to the cells inheriting the old cell end. Furthermore, the new SPB also preferentially segregated to the cells inheriting the old end. Our results suggest that the ability to distinguish ‘old’ from ‘new’ and to segregate DNA asymmetrically are inherent features even in simple unicellular eukaryotes.     

Role of the DELSEED Loop in Torque Transmission of F1-ATPase

F₁-ATPase is an ATP-driven rotary motor that generates torque at the interface between the catalytic β-subunits and the rotor γ-subunit. The β-subunit inwardly rotates the C-terminal domain upon nucleotide binding/dissociation; hence, the region of the C-terminal domain that is in direct contact with γ—termed the DELSEED loop—is thought to play a critical role in torque transmission. We substituted all the DELSEED loop residues with alanine to diminish specific DELSEED loop-γ interactions and with glycine to disrupt the loop structure. All the mutants rotated unidirectionally with kinetic parameters comparable to those of the wild-type F₁, suggesting that the specific interactions between DELSEED loop and γ is not involved in cooperative interplays between the catalytic β-subunits. Glycine substitution mutants generated half the torque of the wild-type F₁, whereas the alanine mutant generated comparable torque. Fluctuation analyses of the glycine/alanine mutants revealed that the γ-subunit was less tightly held in the α₃β₃-stator ring of the glycine mutant than in the wild-type F₁ and the alanine mutant. Molecular dynamics simulation showed that the DELSEED loop was disordered by the glycine substitution, whereas it formed an α-helix in the alanine mutant. Our results emphasize the importance of loop rigidity for efficient torque transmissions.     

Expression of prohibitins on the surface of activated T cells

Prohibitins (prohibitin-1 and -2) comprise a family of highly conserved proteins that are mainly localized to mitochondria. Recent studies showed that prohibitins are up-regulated upon T cell activation and play an essential role in maintaining mitochondrial homeostasis. In the present study, we found that a considerable proportion of prohibitin-1 and -2 induced in response to T cell activation was expressed on the surface of activated T cells. When mouse and human T cells were stimulated with PMA and ionomycin, prohibitins expressed on the cell surface were increased significantly, peaking at 48 h after stimulation. Stimulation of mouse T cells with anti-CD3 and anti-CD28 antibodies also remarkably induced the cell surface expression of prohibitins. Their expression on the cell surface was also detected in T cell leukemia cells such as Jurkat cells. In Jurkat cells, prohibitin-1 and -2 were co-localized with CD3 on the cell surface, and anti-CD3 antibody-induced signaling, the MAP kinase cascade, was inhibited on treatment with protein A magnetic beads co-conjugated with anti-CD3 antibody and anti-prohibitin-1 or anti-prohibitin-2 antibody. These results suggest that prohibitins expressed on the surface of activated T cells are involved in the T cell receptor-mediated signaling cascade.     

A phase II trial of intraperitoneal interleukin-2 in patients with platinum-resistant or platinum-refractory ovarian cancer

Ovarian cancer patients with persistent (platinum-resistant) or progressive (platinum-refractory) disease respond poorly to second line chemotherapy and have low survival expectancy. New and improved therapeutic approaches are needed and immune biologics are one possibility. Interleukin-2 (IL-2) is a T-cell growth factor believed to be important in anti-tumor immunity. We performed a phase II clinical trial with intraperitoneal (IP) recombinant IL-2 administered in weekly infusions of 6 × 10⁵ IU/m². Thirty-one subjects were sequentially entered into the study and clinical responses were surgically confirmed in 24 patients. The primary end point of this study was clinical response with immunologic measurements as secondary end points. The IP regimen was generally well tolerated. Of the 24 patients assessed for response, there were 6 (4 complete, 2 partial) responses for an overall response rate of 25.0% [95% confidence interval (CI) of 11–45]. The median survival of the 31 patient cohort was 2.1 years (95% CI of 1.3–4.4), but for the 6 patients with responses the median survival has not been reached (range 24–120+ months). Eosinophil and lymphocyte numbers were continuously monitored during treatment. Peripheral blood eosinophils were markedly increased at the completion of treatment (p < 0.0001) and associated with increased circulating eotaxin (p = 0.03). We also found significant associations between changes in CD3 counts and survival (p = 0.05) and between IFNγ-secreting CD8 T cells at early time points and survival (p = 0.04). This study provides important evidence for IP IL-2 in platinum-resistant ovarian cancer and identifies several immune correlates of survival.