SummaryThis study tested the feasibility of oral immunotherapy for bronchial asthma using a newly developed subunit vaccine in which a fragment (p45-145) of mite allergen (Der p 1) containing immunodominant human and mouse T cell epitopes was encapsulated in endoplasmic reticulum-derived protein bodies of transgenic (Tg) rice seed. Allergen-specific serum immunoglobulin responses, T cell proliferation, Th1 ⁄ Th2 cytokine production, airway inflammatory cell infiltration, bronchial hyper-responsiveness (BHR) and lung histology were investigated in allergen-immunized and -challenged mice. Prophylactic oral vaccination with the Tg rice seeds clearly reduced the serum levels of allergen-specific IgE and IgG. Allergen-induced CD4 + T cell proliferation and production of Th2 cytokines in vitro, infiltration of eosinophils, neutrophils and mononuclear cells into the airways and BHR were also inhibited by oral vaccination. The effects of the vaccine were antigen-specific immune response because the levels of specific IgE and IgG in mice immunized with Der f 2 or ovalbumin were not significantly suppressed by oral vaccination with the Der p 1 expressing Tg rice. Thus, the vaccine does not induce nonspecific bystander suppression, which has been a problem with many oral tolerance regimens. These results suggest that our novel vaccine strategy is a promising approach for allergen-specific oral immunotherapy against allergic diseases including bronchial asthma.

Over the past few decades, the prevalence of overweight and obesity has increased markedly worldwide, along with the adoption of westernized lifestyles characterized by excessive energy intake and a lack of physical activity. Consequently, obesity and a cluster of obesity-related comorbidities often referred to as the metabolic syndrome have become a serious public health problem and a major risk factor for the development of severe diseases such as cardiovascular disease. 1) Obesity is strongly associated with insulin resistance, in which elevation of circulating fatty acids results in increased fatty acid availability that exceeds the fat disposal capacity of cells, which decreases insulin-stimulated glucose oxidation in muscles and subsequently leads to contractile dysfunction of the heart. 2) The precise mechanisms underlying these "lipotoxic" consequences remain incompletely defined, but it is currently accepted that excessive fatty acid uptake into cells leads to the accumulation of proinflammatory lipid metabolites such as fatty acyl-CoA, diacylglycerol and ceramide. These metabolites stimulate stress-activated kinases, which interfere with insulin signaling. 2,3) It is also becoming clear that fatty acid beta-oxidation is increased in the insulin-resistant heart and oxidative skeletal muscle, and that mitochondrial overload and incomplete oxidation of fatty acids contribute to the impairment of insulin sensitivity. 2,4) Under these conditions, enhanced beta-oxidation, which is not accompanied by appropriate upregulation of the tricarboxylic acid (TCA) cycle or electron transport chain (ETC) activity, fails to oxidize fatty acids completely to CO 2 and deposits incomplete fat catabolites along with diminished levels of TCA cycle intermediates. These stressful environments created within mitochondria are thought to exacerbate cellular insulin resistance by enhanced oxidative stress, for example. 4) However, acyl-CoA thioesterase (ACOT) exists within the mitochondrial matrix of mammalian cells 5) and its expression is expected to be upregulated in response to fatty acid overload, as demonstrated in diabetic and fasted animals. 6,7) ACOT comprises a group of enzymes that are localized in multiple compartments in cells and catalyze the hydrolysis of long-chain acyl-CoA thioesters to free fatty acids and CoA-SH. For example, ACOT1 (formerly known as CTE-I or ACH2) and ACOT7a (CTE-II, BACH or ACT) are localized in the cytosol while ACOT2 (MTE-I or ARTISt) and ACOT7b (MTE-II or LACH1) are present in mitochondria. [8][9][10] These catalytic properties of ACOT mean that it is capable of lowering the increased levels of acyl-CoA imported by carnitine palmitoyltransferase (CPT) across the mitochondrial membranes from the cytosol. Accordingly, ACOT could counteract the enhanced beta-oxidation and reduce the mitochondrial stress caused by the imbalance between beta-oxidation and TCA cycle/ETC activity during fatty acid overload. Moreover, the ACOT isoforms present in the cytosol could scavenge surplus acyl-CoA to prev...

There were notable differences in allergic lung inflammation mediated by different T cell subsets. CCR4 blockage was selectively effective for suppression of Th2-mediated allergic inflammation by blocking infiltration of Th2 cells.

Organic solute carrier protein 1 (OSCP1) is a recently described human gene that facilitates the transport of various organic solutes into the cell, when expressed in frog eggs. In this study, we cloned a mouse ortholog of OSCP1 encoding 379 amino acid protein, with 94% homology to the human counterpart. The mouse OSCP1 mRNA was predominantly expressed in the testis, in which it was attributed to the spermatogenic cells, except the spermatogonia. Immunohistochemistry confirmed that OSCP1 protein is continuously expressed during spermatogenesis in a stage- and cell type-specific manner, in the leptotene spermatocytes at stage IX through step 15 spermatids. Subcellular fractionation of mouse testis homogenates indicated that OSCP1 is a 45-kDa cytosolic protein. Moreover, when green fluorescent protein-OSCP1 fusion constructs were transfected into cultured cells, the fluorescence localized evenly in the cytoplasm. These results suggest that mouse testis OSCP1 may indirectly mediate substrate uptake into meiotic and spermiogenic germ cells, within the cytosol.

Lipid droplets (LDs) are ubiquitous organelles that contain neutral lipids and are surrounded by a phospholipid monolayer. How proteins specifically localize to the phospholipid monolayer of the LD surface has been a matter of extensive investigations. In the present study, we show that syntaxin 17 (Stx17), a soluble -ethylmaleimide-sensitive factor attachment protein receptor (SNARE) protein whose expression in the liver is regulated by diet, participates in LD biogenesis by regulating the distribution of acyl-CoA synthetase (ACSL)3, a key enzyme for LD biogenesis that redistributes from the endoplasmic reticulum (ER) to LDs during LD formation. Stx17 interacts with ACSL3, but not with LD formation-unrelated ACSL1 or ACSL4, through its SNARE domain. The interaction occurs at the ER-mitochondria interface and depends on the active site occupancy of ACSL3. Depletion of Stx17 impairs ACSL3 redistribution to nascent LDs. The defect in LD maturation due to Stx17 knockdown can be compensated for by ACSL3 overexpression, suggesting that Stx17 increases the efficiency of ACSL3 redistribution to LDs. Moreover, we show that the interaction between Stx17 and ACSL3 during LD maturation may be regulated by synaptosomal-associated protein of 23 kDa.