Plasma interleukin (IL)-18 (interferon-gamma-inducing factor) and other inflammatory cytokines in patients with gouty arthritis and monosodium urate monohydrate crystal-induced secretion of IL-18

To determine whether levels of interleukin (IL)-18, together with those of IL-1beta, tumor necrosis factor-alpha, IL-6, and IL-8, are elevated in the plasma of patients with gouty arthritis, the plasma concentrations of those cytokines were measured in 31 males with gouty arthritis. Further, CD14+ cells were obtained from human blood and thioglycolate medium-induced peritoneal cells obtained from caspase 1-deficient mice, and then separately cultured in the presence of monosodium urate monohydrate (MSU) crystals. In addition, in an animal in vivo experiment, MSU crystals were injected into subcutaneous air pouches of IL-18-deficient mice. The plasma concentrations of IL-18, IL-6, and IL-8 were elevated in the presence of gouty arthritis in the gout patients. In the in vitro study, the presence of MSU crystals stimulated CD14+ cells (monocytes) to secrete IL-18 and increased the activity of caspase 1 in CD14+ cells, whereas there was no significant effect on IL-18 messenger RNA in CD14+ cells and only a slight induction of IL-18 secretion from thioglycolate medium-induced caspase 1-deficient peritoneal cells. In the in vivo experiment, MSU crystals injected into the air pouch promoted neutrophil accumulation along with an increase in concentrations of keratinocyte-derived chemokine (KC) and macrophage inflammatory protein (MIP)-1alpha in air-pouch fluids in both IL-18-deficient and wild-type mice. However, there was no increase in the concentration of IL-18 in air-pouch fluids in either mouse strain. Our results suggest that plasma IL-18, IL-6, IL-8, and C-reactive protein (CRP) levels reflect local inflammation associated with gouty arthritis, though IL-18 does not play an important role in neutrophil accumulation. Further, they suggest that MSU crystals accelerate the processing of IL-18 from an inactive to active form via the activation of caspase 1.     

Walking activity of flightless Harmonia axyridis (Coleoptera: Coccinellidae) as a biological control agent

The use of flightless strains of the multicolored Asian lady beetle, Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), established via artificial selection, can be highly effective as a biological control agent for aphids. However, flightless H. axyridis must depend on walking for dispersion. Therefore, data on the walking activity levels in flightless strains are important for the development of effective methods when releasing these agents in the field. Results of measurement of walking activity levels using an infrared actograph showed that walking activity levels during the daytime (but not nighttime) in both sexes of pure flightless strains tended to be lower than those of control strains. We also found that walking activity levels during the daytime for the F1 generation of hybrid strains, produced by reciprocal crossing between two pure flightless strains, were approximately equal to those of pure strains; the reduction in walking activity levels was not recovered by hybrid vigor. Our results indicate that the reduction in walking activity levels in the pure flightless strains was not caused merely by inbreeding depression stemming from the artificial selection process. Instead, potentially flight ability and walking activity levels in this species may be controlled by the pleiotropic effect of a gene.     

Tankyrase-1 assembly to large protein complexes blocks its telomeric function

Tankyrase-1 poly(ADP-ribosyl)ates the telomere-binding protein TRF1. This post-translational modification dissociates TRF1 from telomeres, enhancing telomerase-mediated telomere elongation. Tankyrase-1 multimerizes via its sterile alpha motif domain, but its functional implication remains elusive. Here, we found that excessive amounts of tankyrase-1 form punctate nuclear foci. This focus formation depends on both homophilic multimerization and heterophilic protein-protein interaction. These foci are functionally dormant because they do not efficiently release TRF1 from telomeres. Consistently, hyper-overexpression of tankyrase-1 attenuates its ability to elongate telomeres. These observations suggest that tankyrase-1 assembly to large protein complexes masks its telomeric function.

Structured summary

MINT-7987689, MINT-7987677: Tankyrase-1 (uniprotkb:O95271) and TRF1 (uniprotkb:P54274) colocalize (MI:0403) by fluorescence microscopy (MI:0416)MINT-7987977: Tankyrase-1 (uniprotkb:O95271) physically interacts (MI:0915) with TRF1 (uniprotkb:P54274) by anti tag coimmunoprecipitation (MI:0007)MINT-7987998: Tankyrase-1 (uniprotkb:O95271) physically interacts (MI:0915) with Tankyrase-1 (uniprotkb:O95271) by anti tag coimmunoprecipitation (MI:0007).     

Overexpression of glutathione peroxidase attenuates myocardial remodeling and preserves diastolic function in diabetic heart

Oxidative stress plays an important role in the structural and functional abnormalities of diabetic heart. Glutathione peroxidase (GSHPx) is a critical antioxidant enzyme that removes H(2)O(2) in both the cytosol and mitochondia. We hypothesized that the overexpression of GSHPx gene could attenuate left ventricular (LV) remodeling in diabetes mellitus (DM). We induced DM by injection of streptozotocin (160 mg/kg ip) in male GSHPx transgenic mice (TG+DM) and nontransgenic wildtype littermates (WT+DM). GSHPx activity was higher in the hearts of TG mice compared with WT mice, with no significant changes in other antioxidant enzymes. LV thiobarbituric acid-reactive substances measured in TG+DM at 8 wk were significantly lower than those in WT+DM (58 +/- 3 vs. 71 +/- 5 nmol/g, P < 0.05). Heart rate and aortic blood pressure were comparable between groups. Systolic function was preserved normal in WT+DM and TG+DM mice. In contrast, diastolic function was impaired in WT+DM and was improved in TG+DM as assessed by the deceleration time of peak velocity of transmitral diastolic flow and the time needed for relaxation of 50% maximal LV pressure to baseline value (tau; 13.5 +/- 1.2 vs. 8.9 +/- 0.7 ms, P < 0.01). The TG+DM values were comparable with those of WT+Control (tau; 7.8 +/- 0.2 ms). Improvement of LV diastolic function was accompanied by the attenuation of myocyte hypertrophy, interstitial fibrosis, and apoptosis. Overexpression of GSHPx gene ameliorated LV remodeling and diastolic dysfunction in DM. Therapies designed to interfere with oxidative stress might be beneficial to prevent cardiac abnormalities in DM.     

Salicylic acid and a chitin elicitor both control expression of the CAD1 gene involved in the plant immunity of Arabidopsis

The Arabidopsis mutant cad1 (constitutively activated cell death 1) shows a phenotype that mimics hypersensitive response (HR)-like cell death. The CAD1 gene, which encodes a protein containing a domain with significant homology to the MACPF (membrane attach complex and perforin) domain of complement components and perforin, is likely to control plant immunity negatively and has a W-box cis-element in its promoter region. We found that expression of the CAD1 gene and other W-box containing genes, such as NPR1 and PR2, was promoted by salicylic acid (SA) and benzothiadiazole (BTH) as a SA agonist. The CAD1 gene was also stimulated by a purified chitin oligosaccharide elicitor (degree of polymerization = 8). This latter control was not under SA, because CAD1 expression was not suppressed in 35SnahG transgenic plants, which are unable to accumulate SA. These expression profiles were confirmed by promoter analysis using pCAD1::GUS transgenic plants. The CAD1 expression promoted by BTH and the chitin elicitor was not suppressed in the npr1 mutant, which is insensitive to SA signaling. These results indicate that the CAD1 gene is regulated by two distinct pathways involving SA and a chitin elicitor: viz., SA signaling mediated through an NPR1-independent pathway, and chitin elicitor signaling, through an SA-independent pathway. Three CAD1 homologs that have multiple W-box elements in their promoters were also found to be under the control of SA.     

A plant growth retardant, uniconazole, is a potent inhibitor of ABA catabolism in Arabidopsis

Plant growth retardants (PGRs) reduce the shoot growth of plants by inhibiting gibberellin biosynthesis. In this study, we performed detailed analyses of the inhibitory effects of PGRs on Arabidopsis abscisic acid (ABA) 8'-hydroxylase, a major ABA catabolic enzyme, recently identified as CYP707As. In an in vitro assay with CYP707A3 microsomes expressed in insect cells, uniconazole-P inhibited CYP707A3 activity more effectively than paclobutrazol or tetcyclacis, whereas the other PGRs tested did not inhibit it significantly. Uniconazole-P was found to be a strong competitive inhibitor (K(i)=8.0 nM) of ABA 8'-hydroxylase. Uniconazole-P-treated Arabidopsis plants showed enhanced drought tolerance. In uniconazole-P-treated plants, endogenous ABA levels increased 2-fold as compared with the control, and co-application of GA(4) did not suppress the effects, indicating that the effects were not due to gibberellin deficiency. Thus uniconazole-P effectively inhibits ABA catabolism in Arabidopsis plants. We also discuss the structure-activity relationship of the azole-type compounds on ABA 8'-hydroxylase inhibitory activity.     

Effect of ABA upon anthocyanin synthesis in regenerated torenia shoots

To elucidate the mechanism of anthocyanin synthesis induction concomitant with chlorophyll degradation, we established a system in which anthocyanin synthesis and degradation of chlorophyll in regenerated torenia (Torenia fournieri) shoots was induced on medium containing 7% sucrose. Here, we studied the effect of several plant-growth regulators on anthocyanin synthesis and the degradation of chlorophyll in the torenia shoot regenerating system. Exogenous abscisic acid (ABA) could induce anthocyanin synthesis and chlorophyll senescence in regenerating torenia shoots on the medium containing a low concentration of sucrose (1.5%). We determined the changes in the amount of endogenous ABA in the regenerated shoots during the process of anthocyanin synthesis on the medium containing 7% sucrose. It was revealed that the 7% sucrose treatment elevated endogenous ABA levels before the induction of anthocyanin synthesis and chlorophyll degradation. However, while retransfer to the 1.5% sucrose medium resulted in a gradual decrease in the ABA level and a failure of induction of anthocyanin synthesis, normal shoot regeneration. These results suggest that changes in the amount of endogenous ABA may play an important role in the induction of anthocyanin synthesis and chlorophyll degradation in regenerated torenia shoots.     

Prolactin-releasing peptide is essential to maintain the prolactin level and osmotic balance in freshwater teleost fish

We administered prolactin-releasing peptide (PrRP) or anti-PrRP antiserum to goldfish in fresh water and analyzed their effects on prolactin and osmoregulatory mechanisms. The pituitary mRNA level of prolactin increased by PrRP but decreased by anti-PrRP. The rate of water inflow in the gills decreased by PrRP and increased by anti-PrRP, showing that PrRP restricts branchial water permeability, as also restricted by prolactin. PrRP also expanded the mucous cell layers on the scales, which may restrict efficiently water inflow by the mucous system. Eventually, the plasma osmotic pressure decreased by anti-PrRP. We conclude that PrRP is essential to maintain prolactin levels and osmotic balance in fresh water.     

Hypothalamic LPXRF-amide peptides in vertebrates: identification, localization and hypophysiotropic activity

Probing undiscovered neuropeptides that play important roles in the regulation of pituitary function in vertebrates is essential for the progress of neuroendocrinology. Recently, we identified a novel hypothalamic neuropeptide with a C-terminal LPLRF-amide sequence in the quail brain. This avian neuropeptide was shown to be located in the hypothalamo-hypophysial system and to decrease gonadotropin release from cultured anterior pituitary. We, therefore, designated this novel neuropeptide as gonadotropin-inhibitory hormone (GnIH). We further identified novel hypothalamic neuropeptides closely related to GnIH in the brains of other vertebrates, such as mammals, amphibians, and fish. The identified neuropeptides possessed a LPXRF-amide (X = L or Q) motif at their C-termini. These LPXRF-amide peptides also were localized in the hypothalamus and other brainstem areas and regulated pituitary hormone release. Subsequently, cDNAs that encode LPXRF-amide peptides were characterized in vertebrate brains. In this review, we summarize the identification, localization, and hypophysiotropic activity of these newly identified hypothalamic LPXRF-amide peptides in vertebrates.     

Cleavage of amyloid-beta precursor protein (APP) by membrane-type matrix metalloproteinases

Amyloid-beta precursor protein (APP) was identified on expression cloning from a human placenta cDNA library as a gene product that modulates the activity of membrane-type matrix metalloproteinase-1 (MT1-MMP). Co-expression of MT1-MMP with APP in HEK293T cells induced cleavage and shedding of the APP ectodomain when co-expressed with APP adaptor protein Fe65. Among the MT-MMPs tested, MT3-MMP and MT5-MMP also caused efficient APP shedding. The recombinant APP protein was cleaved by MT3-MMP in vitro at the A463-M464, N579-M580, H622-S623, and H685-Q686 peptide bonds, which included a cleavage site within the amyloid beta peptide region known to produce a C-terminal fragment. The Swedish-type mutant of APP, which produces a high level of amyloid beta peptide, was more effectively cleaved by MT3-MMP than wild-type APP in both the presence and absence of Fe65; however, amyloid beta peptide production was not affected by MT3-MMP expression. Expression of MT3-MMP enhanced Fe65-dependent transactivation by APP fused to the Gal4 DNA-binding and transactivation domains. These results suggest that MT1-MMP, MT3-MMP and MT5-MMP should play an important role in the regulation of APP functions in tissues including the central nervous system.