Rapid increase in endothelial nitric oxide production by bradykinin is mediated by protein kinase A signaling pathway

Bradykinin (BK) acutely increases endothelial nitric oxide (NO) production by activating endothelial NO synthase (eNOS), and this increase is in part correlated with enhanced phosphorylation/dephosphorylation of eNOS by several protein kinases and phosphatases. However, the signaling mechanisms producing this increase are still controversial. In an attempt to delineate the acute effect of BK on endothelial NO production, confluent bovine aortic endothelial cells were incubated with BK, and NO production was measured by NO-specific chemiluminescence. Significant increase in NO levels was detected as early as 1 min after BK treatment, with concomitant increase in the phosphorylation of Ser(1179) (bovine sequence) site of eNOS (eNOS-Ser(1179)). This acute effect of BK on both increases was blocked only by treatment of protein kinase A inhibitor H-89, but not by the inhibitors of calmodulin-dependent kinase II and protein kinase B, suggesting that the rapid increase in NO production by BK is mediated by the PKA-dependent phosphorylation of eNOS-Ser(1179).     

IgE production in CD40/CD40L cross-talk of B and mast cells and mediator release via TGase 2 in mouse allergic asthma

TGase 2 is over-expressed in a variety of inflammatory diseases including allergic asthma. This study aimed to investigate the role of TGase 2 on IgE production and signaling pathways in mast cell activation related to OVA-induced allergic asthma. Bone marrow-derived mast cells (BMMCs) isolated from WT or TGase 2^?/? mice were activated with Ag/Ab (refer to act-WT-BMMCs and act-KO-BMMCs, respectively). B cells isolated from splenocytes were activated with anti-mouse IgM (act-B cells), and B cells were co-cultured with BMMCs. WT and TGase 2^?/? mice were sensitized and challenged with OVA adsorbed in alum hydroxide. Intracellular Ca^2 + ([Ca^2 +]_i) levels were determined by fluorescence intensity; IgE, mediators and TGase 2 activity by ELISA; the CD138 expression by FACS analyzer; cell surface markers and signal molecules by Western blot; NF-κB by EMSA; co-localization of mast cells and B cells by immunohistochemistry; Fcε RI-mediated mast cell activation by PCA test; expression of cytokines, MMPs, TIMPs, TLR2 and Fc?RI by RT-PCR. In vitro, act-KO-BMMCs reduced the [Ca^2 +]i levels, NF-κB activity, expression of CD40/CD40L, plasma cells, total IgE levels and TGase 2 activity in act-B cells co-cultured with act-BMMCs, expression of inflammatory cytokines and MMPs2/9, release of mediators (TNF-α, LTs and cytokines), and activities of signal molecules (PKCs, MAP kinases, I-κB and PLA2), which were all increased in act-WT-BMMCs. TGase 2 siRNA transfected/activated-BMMCs reduced all responses as same as those in act-KO-BMMCs. In allergic asthma model, TGase 2^?/? mice protected against PCA reaction, OVA-specific IgE production and AHR, and they reduced co-localization of mast cells and B cells or IgE in lung tissues, expression and co-localization of surface molecules in mast cells (c-kit and CD40L) and B cells (CD23 and CD40), inflammatory cells including mast cells, goblet cells, amounts of collagen and mediator release in BAL fluid and/or lung tissues, which were all increased in WT mice. TLR expression in TGase 2^?/? mice did not differ from those in WT mice. Our data suggest that TGase 2 expression and Ca^2 + influx required by bidirectional events in mast cell activation facilitate IgE production in B cells via up-regulating mast cell CD40L expression, and induce the expression of numerous signaling molecules associated with airway inflammation and remodeling in allergic asthma.     

Gender-Specific Metabolomic Profiling of Obesity in Leptin-Deficient ob/ob Mice by 1H NMR Spectroscopy

Despite the numerous metabolic studies on obesity, gender bias in obesity has rarely been investigated. Here, we report the metabolomic analysis of obesity by using leptin-deficient ob/ob mice based on the gender. Metabolomic analyses of urine and serum from ob/ob mice compared with those from C57BL/6J lean mice, based on the ¹H NMR spectroscopy in combination with multivariate statistical analysis, revealed clear metabolic differences between obese and lean mice. We also identified 48 urine and 22 serum metabolites that were statistically significantly altered in obese mice compared to lean controls. These metabolites are involved in amino acid metabolism (leucine, alanine, ariginine, lysine, and methionine), tricarbocylic acid cycle and glucose metabolism (pyruvate, citrate, glycolate, acetoacetate, and acetone), lipid metabolism (cholesterol and carnitine), creatine metabolism (creatine and creatinine), and gut-microbiome-derived metabolism (choline, TMAO, hippurate, p-cresol, isobutyrate, 2-hydroxyisobutyrate, methylamine, and trigonelline). Notably, our metabolomic studies showed distinct gender variations. The obese male mice metabolism was specifically associated with insulin signaling, whereas the obese female mice metabolism was associated with lipid metabolism. Taken together, our study identifies the biomarker signature for obesity in ob/ob mice and provides biochemical insights into the metabolic alteration in obesity based on gender.     

Metformin modifies the exercise training effects on risk factors for cardiovascular disease in impaired glucose tolerant adults

Impaired glucose tolerant (IGT) adults are at elevated risk for cardiovascular disease (CVD). Exercise or metformin reduce CVD risk, but the efficacy of combining treatments is unclear.

Objective:

To determine the effects of exercise training plus metformin (EM), compared with each treatment alone, on CVD risk factors in IGT adults.

Design and Methods:

Subjects were assigned to placebo (P), metformin (M), exercise training plus placebo (EP), or EM (8/group). In a double‐blind design, P or 2,000 mg/d of M were administered for 12 weeks and half performed aerobic and resistance training 3 days/week for ～60 min/day at 70% pretraining heart rate peak. Outcomes included adiposity, blood pressure (BP), lipids, and high sensitivity C‐reactive protein (hs‐CRP). Z‐scores were calculated to determine metabolic syndrome severity.

Results:

M and EM, but not EP, decreased body weight compared with P (P < 0.05). M and EP lowered systolic blood pressure by 6% (P < 0.05), diastolic blood pressure by 6% (P < 0.05), and hs‐CRP by 20% (M: trend P = 0.06; EP: P < 0.05) compared with P. Treatments raised high‐density lipoprotein cholesterol (P < 0.05; EM: trend P = 0.06) compared with P and lowered triacyglycerol (P < 0.05) and metabolic syndrome Z‐score compared with baseline (EP; trend P = 0.07 and EM or M; P < 0.05).

Conclusions:

Although exercise and/or metformin improve some CVD risk factors, only training or metformin alone lowered hs‐CRP and BP. Thus, metformin may attenuate the effects of training on some CVD risk factors and metabolic syndrome severity in IGT adults.     

In-gel total protein quantification using a ninhydrin-based method

Precise in-gel quantification of total protein amount of bands or spots in gels is the basis of subsequent biochemical, molecular biological and immunological analyses. Though several methods have been designed to evaluate relative amounts of proteins, these methods are of limited reliability because (semi-) quantifications depend on the amount of protein migrating into the gel and different proteins may lead to different absorptions/intensities of stained bands or spots. In the present study, we described a method to quantify both, hydrophilic and hydrophobic proteins using in-gel digestion with proteinase K, subsequent extraction and acid hydrolysis followed by the use of the ninhydrin reaction. The protocol is accurate and compatible with mass spectrometric characterization of proteins. Reproducible in-gel protein quantification was performed from SDS-PAGE and IEF/SDS-PAGE gels using bovine serum albumin as a standard protein. Bacteriorhodopsin separated on SDS-PAGE gel was quantified in addition in order to show that the method is also suitable for quantification of hydrophobic protein. This protocol for reliable in-gel protein quantification, which not only provides “arbitrary units of optical density”, can also be completed in a minimum of 4 days or maximum 1 week depending on the type of electrophoresis with the disadvantage of being time consuming.     

Comparison of the Effects of Cuprizone on Demyelination in the Corpus Callosum and Hippocampal Progenitors in Young Adult and Aged Mice

Neurochemical Research - Cuprizone is commonly used to induce neuronal demyelination in mice. In the present study, we compared the cuprizone-induced demyelination in the corpus callosum and...     

Mutagenesis of phospholipase D defines a superfamily including a trans-Golgi viral protein required for poxvirus pathogenicity.

Phospholipase D (PLD) genes are members of a superfamily that is defined by several highly conserved motifs. PLD in mammals has been proposed to play a role in membrane vesicular trafficking and signal transduction. Using site-directed mutagenesis, 25 point mutants have been made in human PLD1 (hPLD1) and characterized. We find that a motif (HxKxxxxD) and a serine/threonine conserved in all members of the PLD superfamily are critical for PLD biochemical activity, suggesting a possible catalytic mechanism. Functional analysis of catalytically inactive point mutants for yeast PLD demonstrates that the meiotic phenotype ensuing from PLD deficiency in yeast derives from a loss of enzymatic activity. Finally, mutation of an HxKxxxxD motif found in a vaccinia viral protein expressed in the Golgi complex results in loss of efficient vaccinia virus cell-to-cell spreading, implicating the viral protein as a member of the superfamily and suggesting that it encodes a lipid modifying or binding activity. The results suggest that vaccinia virus and hPLD1 may act through analogous mechanisms to effect viral cellular egress and vesicular trafficking, respectively.     

Syntheses of sphingosine-1-phosphate stereoisomers and analogues and their interaction with EDG receptors

Sphingosine-1-phosphate (S1P) is considered to be an important regulator of diverse biological processes acting as a natural ligand to EDG receptors. As a preliminary study to develop potent and selective agonist and antagonist for EDG receptors, we report synthesis of S1P stereoisomers and analogues and their binding affinities to EDG-1, -3, and -5.     

Calcium spikes in a leech nonspiking neuron

The NS neurons are nonspiking cells, present as pairs in each midbody ganglion of the leech nervous system, which display a very extensive arborization. They were shown to regulate the coactivation of motoneurons. Here we have investigated the electrophysiological properties of these neurons under the hypothesis that transmission along the extensive neurites requires the aid of voltage-dependent conductances. The results indicate that NS neurons respond to electrical stimulation with a spike-like event, which was not an all-or-none but rather a graded phenomenon that depended on the intensity and duration of the electrical stimulus. The spike-like response was activated at a membrane potential of approximately −50 mV; its amplitude was a logarithmic function of the extracellular Ca²⁺ concentration and was unaffected by a broad range of changes in the extracellular Na⁺ concentration; intracellular application of tetraethylammonium (TEA) caused a large increase in its amplitude and duration. These data indicate that NS neurons bear voltage-dependent low-threshold Ca²⁺ and TEA-sensitive K⁺ conductances that could contribute to shaping synaptic signals, or transmission along the extensive neuritic tree.