ADRP is dissociated from lipid droplets by ARF1-dependent mechanism

Adipocyte differentiation-related protein (ADRP) is a member of PAT proteins existing in lipid droplets (LDs). By yeast two-hybrid screening, we identified ADP-ribosylation factor 1 (ARF1) as a binding partner of ADRP. The interaction of ADRP and ARF1 was verified by GST pull-down and co-immunoprecipitation experiments. Interestingly, ADRP precipitated the GDP-bound ARF1 preferentially to the GTP-bound ARF1. Consistent with this, either brefeldin A (BFA), a fungal metabolite to inhibit ARF-GEF, or a dominant-negative mutant of ARF1 caused dissociation of ADRP from LD. On the other hand, overexpression of wild-type ARF1 did not promote the ADRP dissociation or new LD formation. By using deletion mutants, a central domain of ADRP, which is dispensable for LD binding, was shown to bind to ARF1. The present study showed that the GDP-bound ARF1 induces dissociation of ADRP from the LD surface, and that LD is a target of BFA action.     

Ectopic CD40 ligand expression on B cells triggers intestinal inflammation

Several studies indicate that CD4(+) T cells, macrophages, and dendritic cells initially mediate intestinal inflammation in murine models of human inflammatory bowel disease. However, the initial role of B cells in the development of intestinal inflammation remains unclear. In this study we present evidence that B cells can trigger intestinal inflammation using transgenic (Tg) mice expressing CD40 ligand (CD40L) ectopically on B cells (CD40L/B Tg). We demonstrated that CD40L/B Tg mice spontaneously developed severe transmural intestinal inflammation in both colon and ileum at 8-15 wk of age. In contrast, CD40L/B TgxCD40(-/-) double-mutant mice did not develop colitis, indicating the direct involvement of CD40-CD40L interaction in the development of intestinal inflammation. The inflammatory infiltrates consisted predominantly of massive aggregated, IgM-positive B cells. These mice were also characterized by the presence of anti-colon autoantibodies and elevated IFN-gamma production. Furthermore, although mice transferred with CD4(+) T cells alone or with both CD4(+) T and B220(+) B cells, but not B220(+) cells alone, from diseased CD40L/B Tg mice, develop colitis, mice transferred with B220(+) B cells from diseased CD40L/B Tg mice and CD4(+) T cells from wild-type mice also develop colitis, indicating that the Tg B cells should be a trigger for this colitis model, whereas T cells are involved as effectors. As it has been demonstrated that CD40L is ectopically expressed on B cells in some autoimmune diseases, the present study suggests the possible contribution of B cells in triggering intestinal inflammation in human inflammatory bowel disease.     

Mechanism of fibrogenesis in submandibular glands in patients with IgG4-RD

The aim of this study was to investigate the mechanisms driving fibrosis in the submandibular glands (SMG) of patients with IgG4-related disease (IgG4-RD). Immunohistochemistry showed that many fibroblast-like cells expressing IL-6, IL-18, TSLP, IL-33, and MMP1 were present in SMG from the affected patients. SMG fibroblasts were derived from patients with or without IgG4-RD and were cultured in vitro. Expression of IL-6, IL-18, TSLP, IL-33 and MMP1, the secretion of IL-6 and G2/M phase were upregulated in the fibroblasts from the affected patients. By treatment with inflammatory cytokines IL-1β, TNFα or TGF-β after treatment with or without the NF-κB inhibitor curcumin, curucumin blocked the production and secretion of IL-6 upregulated by IL-1β, TNFα, or TNFα/TGF-β in all fibroblasts. Wnt1-inducible signaling protein 1 (WISP1), which can enhance fibroblasts proliferation, was also more abundantly expressed in affected fibroblasts, while treatment with IL-6 induced WISP1, treatment with WISP1 increased the G2/M phase, and curucumin inhibited WISP1 induced by TNFα/TGF-β in unaffected fibroblasts. IL-33 in affected fibroblasts was induced by IL-1β, TNFα, or TNFα/TGF-β, while the effect of IL-1β or TNFα/TGF-β was blocked by curcumin. These results suggest fibrosis in the SMG of affected patients is closely linked to the proliferation of fibroblasts following induction of IL-6 and WISP1 by inflammatory cytokines. The Th2 cytokines TSLP and IL-33 are also upregulated in affected SMG, and thus may cause chronic inflammation and IgG4 accumulation.     

Diel behavior in moths and butterflies: a synthesis of data illuminates the evolution of temporal activity

Lepidoptera (butterflies and moths) are one of the most taxonomically diverse insect orders with nearly 160,000 described species. They have been studied extensively for centuries and are found on nearly all continents and in many environments. It is often assumed that adult butterflies are strictly diurnal and adult moths are strictly nocturnal, but there are many exceptions. Despite the broad interest in butterflies and moths, a comprehensive review of diel (day-night) activity has not been conducted. Here, we synthesize existing data on diel activity in Lepidoptera, trace its evolutionary history on a phylogeny, and show where gaps lie in our knowledge. Diurnality was likely the ancestral condition in Lepidoptera, the ancestral heteroneuran was likely nocturnal, and more than 40 transitions to diurnality subsequently occurred. Using species diversity estimates across the order, we predict that roughly 75-85% of Lepidoptera are nocturnal. We also define the three frequently used terms for activity in animals (diurnal, nocturnal, crepuscular), and show that literature on the activity of micro-moths is significantly lacking. Ecological factors leading to nocturnality/diurnality is a compelling area of research and should be the focus of future studies.     

QTL affecting fitness of hybrids between wild and cultivated soybeans in experimental fields

The objective of this study was to identify quantitative trait loci (QTL) affecting fitness of hybrids between wild soybean (Glycine soja) and cultivated soybean (Glycine max). Seed dormancy and seed number, both of which are important for fitness, were evaluated by testing artificial hybrids of G. soja × G. max in a multiple‐site field trial. Generally, the fitness of the F₁ hybrids and hybrid derivatives from self‐pollination was lower than that of G. soja due to loss of seed dormancy, whereas the fitness of hybrid derivatives with higher proportions of G. soja genetic background was comparable with that of G. soja. These differences were genetically dissected into QTL for each population. Three QTLs for seed dormancy and one QTL for total seed number were detected in the F₂ progenies of two diverse cross combinations. At those four QTLs, the G. max alleles reduced seed number and severely reduced seed survival during the winter, suggesting that major genes acquired during soybean adaptation to cultivation have a selective disadvantage in natural habitats. In progenies with a higher proportion of G. soja genetic background, the genetic effects of the G. max alleles were not expressed as phenotypes because the G. soja alleles were dominant over the G. max alleles. Considering the highly inbreeding nature of these species, most hybrid derivatives would disappear quickly in early self‐pollinating generations in natural habitats because of the low fitness of plants carrying G. max alleles.     

Metabolic impact of overexpression of liver glycogen synthase with serine-to-alanine substitutions in rat primary hepatocytes

To investigate the effect of elevation of liver glycogen synthase (GYS2) activity on glucose and glycogen metabolism, we performed adenoviral overexpression of the mutant GYS2 with six serine-to-alanine substitutions in rat primary hepatocytes. Cell-free assays demonstrated that the serine-to-alanine substitutions caused constitutive activity and electrophoretic mobility shift. In rat primary hepatocytes, overexpression of the mutant GYS2 significantly reduced glucose production by 40% and dramatically induced glycogen synthesis via the indirect pathway rather than the direct pathway. Thus, we conclude that elevation of glycogen synthase activity has an inhibitory effect on glucose production in hepatocytes by shunting gluconeogenic precursors into glycogen. In addition, although intracellular compartmentation of glucose-6-phosphate (G6P) remains unclear in hepatocytes, our results imply that there are at least two G6P pools via gluconeogenesis and due to glucose phosphorylation, and that G6P via gluconeogenesis is preferentially used for glycogen synthesis in hepatocytes.     

Alpha1-adrenoceptor-dependent vascular hypertrophy and remodeling in murine hypoxic pulmonary hypertension

Excessive proliferation of vascular wall cells underlies the development of elevated vascular resistance in hypoxic pulmonary hypertension (PH), but the responsible mechanisms remain unclear. Growth-promoting effects of catecholamines may contribute. Hypoxemia causes sympathoexcitation, and prolonged stimulation of alpha(1)-adrenoceptors (alpha(1)-ARs) induces hypertrophy and hyperplasia of arterial smooth muscle cells and adventitial fibroblasts. Catecholamine trophic actions in arteries are enhanced when other conditions favoring growth or remodeling are present, e.g., injury or altered shear stress, in isolated pulmonary arteries from rats with hypoxic PH. The present study examined the hypothesis that catecholamines contribute to pulmonary vascular remodeling in vivo in hypoxic PH. Mice genetically deficient in norepinephrine and epinephrine production [dopamine beta-hydroxylase(-/-) (DBH(-/-))] or alpha(1)-ARs were examined for alterations in PH, cardiac hypertrophy, and vascular remodeling after 21 days exposure to normobaric 0.1 inspired oxygen fraction (Fi(O(2))). A decrease in the lumen area and an increase in the wall thickness of arteries were strongly inhibited in knockout mice (order of extent of inhibition: DBH(-/-) = alpha(1D)-AR(-/-) > alpha(1B)-AR(-/-)). Distal muscularization of small arterioles was also reduced (DBH(-/-) > alpha(1D)-AR(-/-) > alpha(1B)-AR(-/-) mice). Despite these reductions, increases in right ventricular pressure and hypertrophy were not attenuated in DBH(-/-) and alpha(1B)-AR(-/-) mice. However, hematocrit increased more in these mice, possibly as a consequence of impaired cardiovascular activation that occurs during reduction of Fi(O(2)). In contrast, in alpha(1D)-AR(-/-) mice, where hematocrit increased the same as in wild-type mice, right ventricular pressure was reduced. These data suggest that catecholamine stimulation of alpha(1B)- and alpha(1D)-ARs contributes significantly to vascular remodeling in hypoxic PH.     

Blockade of both alpha1A- and alpha1B-adrenergic receptor subtype signaling is required to inhibit neointimal formation in the mouse femoral artery

Attenuation of early restenosis after percutaneous coronary intervention (PCI) is important for the successful treatment of coronary artery disease. Some clinical studies have shown that hypertension is a risk factor for early restenosis after PCI. These findings suggest that alpha(1)-adrenergic receptors (alpha(1)-ARs) may facilitate restenosis after PCI because of alpha(1)-AR's remarkable contribution to the onset of hypertension. In this study, we examined the neointimal formation after vascular injury in the femoral artery of alpha(1A)-knockout (alpha(1A)-KO), alpha(1B)-KO, alpha(1D)-KO, alpha(1A)-/alpha(1B)-AR double-KO (alpha(1AB)-KO), and wild-type mice to investigate the functional role of each alpha(1)-AR subtype in neointimal formation, which is known to promote restenosis. Neointimal formation 4 wk after wire injury was significantly (P < 0.05) smaller in alpha(1AB)-KO mice than in any other group of mice, while blood pressures were not altered in any of the groups of mice after wire injury compared with those before it. These results suggest that lack of both alpha(1A)- and alpha(1B)-ARs could be necessary to inhibit neointimal formation in the mouse femoral artery.     

Construction of a stepwise gene integration system by transient expression of actinophage R4 integrase in cyanobacterium Synechocystis sp. PCC 6803

The integrase of actinophage R4, which belongs to the large serine-recombinase family, catalyzes site-specific recombination between two distinct attachment site sequences of the phage (attP) and actinomycete Streptomyces parvulus 2297 chromosome (attB). We previously reported that R4 integrase (Sre) catalyzed site-specific recombination both in vivo and in vitro. In the present study, a Sre-based system was developed for the stepwise site-specific integration of multiple genes into the chromosome of cyanobacterium Synechocystis sp. PCC 6803 (hereafter PCC 6803). A transgene-integrated plasmid with two attP sites and a non-replicative sre-containing plasmid were co-introduced into attB-inserted PCC 6803 cells. The transiently expressed Sre catalyzed highly efficient site-specific integration between one of the two attP sites on the integration plasmid and the attB site on the chromosome of PCC 6803. A second transgene-integrated plasmid with an attB site was integrated into the residual attP site on the chromosome by repeating site-specific recombination. The transformation frequencies (%) of the first and second integrations were approximately 5.1 × 10^?5 and 8.2 × 10^?5, respectively. Furthermore, the expression of two transgenes was detected. This study is the first to apply the multiple gene site-specific integration system based on R4 integrase to cyanobacteria.