Sexual dimorphism in rabbit aortic endothelial function under acute hyperglycemic conditions and gender-specific responses to acute 17beta-estradiol

Epidemiological data suggest that hyperglycemia abrogates the gender-based cardiovascular protection possibly associated with estrogens. This study was designed to investigate 1) whether rabbit aortic rings show gender differences in the development of abnormal endothelium-dependent vasodilation (EDV) under acute hyperglycemic conditions, 2) the potential role of PKC isoforms and superoxide (O2-) in acute hyperglycemia-induced vascular dysfunction, and 3) the effect of acute estrogen administration on hyperglycemia-induced endothelial dysfunction in male and female rabbits. EDV to ACh was determined before and after 3 h of treatment with high glucose (HG) in phenylephrine-precontracted aortic rings from male and female New Zealand White rabbits. Similar experiments were conducted in the presence of inhibitors of PKC-alpha, PKC-beta, and PKC-delta or an O2- scavenger. The effect of acute estrogen administration was evaluated in the presence and absence of HG. Finally, mRNA expression of PKC isoforms was measured by real-time PCR. We found that 1) 3 h of incubation with HG impairs EDV to a greater extent in female than male aorta, 2) inhibition of PKC-beta or O2- prevents HG-induced impairment of EDV in female aorta, 3) acute 17beta-estradiol aggravates HG-induced endothelial dysfunction in female, but not male, aorta, and 4) PKC-alpha and PKC-beta expression are significantly higher in female than male aorta. This study reveals the predisposition of female rabbit aorta to vascular injury under hyperglycemic conditions, possibly via activation of PKC-beta and O2- production. Furthermore, it suggests that, under hyperglycemic conditions, acute estrogen treatment is detrimental to endothelial function in female rabbits.     

Identification of dysregulation of atrial proteins in rats with chronic obstructive apnea using two‐dimensional polyacrylamide gel electrophoresis and mass spectrometry

Obstructive sleep apnea (OSA) affects an estimated 20% of adults worldwide and has been associated with electrical and structural abnormalities of the atria, although the molecular mechanisms are not well understood. Here, we used two‐dimensional polyacrylamide gel electrophoresis (2D PAGE) coupled with nanoliquid chromatography‐tandem mass spectrometry (nanoLC‐MS/MS) to investigate the proteins that are dysregulated in the atria from severe and moderate apnea when compared to control. We found enzymes involved in the glycolysis, beta‐oxidation, electron transport chain and Krebs cycle to be down‐regulated. The data suggested that the dysregulated proteins may play a role in atrial pathology developing via chronic obstructive apnea and hypoxia. Our results are consistent with our previous 1D‐PAGE and nanoLC‐MS/MS study (Channaveerappa et al, J Cell Mol Med. 2017), where we found that some aerobic and anaerobic glycolytic and Krebs cycle enzymes were down‐regulated, suggesting that apnea may be a result of paucity of oxygen and production of ATP and reducing equivalents (NADH). The 2D‐PAGE study not only complements our current study, but also advances our understanding of the OSA. The complete mass spectrometry data are available via ProteomeXchange with identifier PXD011181.     

Down syndrome’s brain dynamics: analysis of fractality in resting state

To the best knowledge of the authors there is no study on nonlinear brain dynamics of down syndrome (DS) patients, whereas brain is a highly complex and nonlinear system. In this study, fractal dimension of EEG, as a key characteristic of brain dynamics, showing irregularity and complexity of brain dynamics, was used for evaluation of the dynamical changes in the DS brain. The results showed higher fractality of the DS brain in almost all regions compared to the normal brain, which indicates less centrality and higher irregular or random functioning of the DS brain regions. Also, laterality analysis of the frontal lobe showed that the normal brain had a right frontal laterality of complexity whereas the DS brain had an inverse pattern (left frontal laterality). Furthermore, the high accuracy of 95.8 % obtained by enhanced probabilistic neural network classifier showed the potential of nonlinear dynamic analysis of the brain for diagnosis of DS patients. Moreover, the results showed that the higher EEG fractality in DS is associated with the higher fractality in the low frequencies (delta and theta), in broad regions of the brain, and the high frequencies (beta and gamma), majorly in the frontal regions.     

Numerical Study of Optical Behavior of Nano-Hole Array with Non-Vertical Sidewall Profile

Due to the limit of nanofabrication methods of the nano-hole array (i.e., focused ion beam, nanoimprint/electron beam lithography, and metal film evaporation on top of the free standing membrane), the nano-hole arrays patterned in a noble metal film always has a non-vertical sidewall profile. In this work, the optical transmittance of the non-vertical profile nano-hole array with different tapered angle (α) and structural periodicity (P) was numerically investigated. The optimum tapered angle in case of positive profile of the nano-hole arrays was found as 10° and 12° at structural period of 450 and 500 nm, respectively. However, in case of negative profile, the optimum tapered angle of the nano-hole array was obtained as 4° at both structural period of 450 and 500 nm. The first and the second resonance modes of the nano-hole arrays with negative profile were shown a blueshift of 16 and 9 nm on increasing the tapered angle from 0° to 16° at structural period of 450 and 500 nm, respectively. It was also found that nano-hole arrays with positive tapered profile result in higher transmission than the negative profile one.     

Design and Synthesis of Novel Arylisoxazole‐Chromenone Carboxamides: Investigation of Biological Activities Associated with Alzheimer's Disease

A novel series of hybrid arylisoxazole‐chromenone carboxamides were designed, synthesized, and evaluated for their cholinesterase (ChE) inhibitory activity based on the modified Ellman's method. Among synthesized compounds, 5‐(3‐nitrophenyl)‐N‐{4‐[(2‐oxo‐2H‐1‐benzopyran‐7‐yl)oxy]phenyl}‐1,2‐oxazole‐3‐carboxamide depicted the most acetylcholinesterase (AChE) inhibitory activity (IC₅₀=1.23 μm ) and 5‐(3‐chlorophenyl)‐N‐{4‐[(2‐oxo‐2H‐1‐benzopyran‐7‐yl)oxy]phenyl}‐1,2‐oxazole‐3‐carboxamide was found to be the most potent butyrylcholinesterase (BChE) inhibitor (IC₅₀=9.71 μm ). 5‐(3‐Nitrophenyl)‐N‐{4‐[(2‐oxo‐2H‐1‐benzopyran‐7‐yl)oxy]phenyl}‐1,2‐oxazole‐3‐carboxamide was further investigated for its BACE1 inhibitory activity as well as neuroprotectivity and metal chelating ability as important factors involved in onset and progress of Alzheimer's disease. It could inhibit BACE1 by 48.46 % at 50 μm . It also showed 6.4 % protection at 25 μm and satisfactory chelating ability toward Zn²⁺, Fe²⁺, and Cu²⁺ ions. Docking studies of 5‐(3‐nitrophenyl)‐N‐{4‐[(2‐oxo‐2H‐1‐benzopyran‐7‐yl)oxy]phenyl}‐1,2‐oxazole‐3‐carboxamide and 5‐(3‐chlorophenyl)‐N‐{4‐[(2‐oxo‐2H‐1‐benzopyran‐7‐yl)oxy]phenyl}‐1,2‐oxazole‐3‐carboxamide confirmed desired interactions with those amino acid residues of the AChE and BChE, respectively.     

The acute-phase protein serum amyloid A induces endothelial dysfunction that is inhibited by high-density lipoprotein

The acute-phase protein serum amyloid A (SAA) is elevated during inflammation and may be deposited in atheroma where it promotes atherosclerosis. We investigated the proatherogenic effects of SAA on the vascular endothelium and their regulation by high-density lipoprotein (HDL). Exposure of human aortic endothelial cells (HAEC) to SAA (0.25-25 μg/ml) decreased nitric oxide (^•NO) synthesis/bioavailability, although the endothelial NO synthase monomer-to-dimer ratio was unaffected. SAA (10 μg/ml) stimulated a Ca²⁺ influx linked to apocynin-sensitive superoxide radical anion (O₂^•−) production. Gene expression for arginase-1, nuclear factor κB (NF-κB), interleukin-8, and tissue factor (TF) increased within 4 h of SAA stimulation. Enzymatically active Arg-1/2 was detected in HAEC cultured with SAA for 24 h. Therefore, in addition to modulating ^•NO bioavailability by stimulating O₂^•− production in the endothelium, SAA modulated vascular l-Arg bioavailability. SAA also diminished relaxation of preconstricted aortic rings induced by acetylcholine, and added superoxide dismutase restored the vascular response. Preincubation of HAEC with HDL (100 or 200, but not 50, μg/ml) before (not after) SAA treatment ameliorated the Ca²⁺ influx and O₂^•− production; decreased TF, NF-κB, and Arg-1 gene expression; and preserved overall vascular function. Thus, SAA may promote endothelial dysfunction by modulating ^•NO and l-Arg bioavailability, and HDL pretreatment may be protective. The relative HDL to SAA concentrations may regulate the proatherogenic properties of SAA on the vascular endothelium.     

Immune amplification of murine CD8 suppressor T cells induced via an immune-privileged site: quantifying suppressor T cells functionally

Background

CD8⁺ suppressor T cells exert antigen-specific suppression of the expression of hypersensitivity by activated T cells. Therefore, CD8⁺ suppressor T cells serve a major regulatory role for the control of active immunity. Accordingly, the number and/or activity of CD8⁺ suppressor T cells should be influenced by an immune response to the antigen. To test this hypothesis we used an adoptive transfer assay that measures the suppression of the expression of delayed-type hypersensitivity (DTH) by CD8⁺ suppressor T cells to quantify the antigen-specific suppression of DTH by these suppressor T cells.

Methods

Suppressor T cells were induced in the spleens of mice by the injection of antigen into the anterior chamber of an eye. Following this injection, the mice were immunized by the same antigen injected into the anterior chamber. Spleen cells recovered from these mice (AC-SPL cells) were titrated in an adoptive transfer assay to determine the number of AC-SPL cells required to effect a 50% reduction of antigen-induced swelling (Sw50) in the footpad of immunized mice challenged by antigen.

Results

Suppression of the expression of DTH is proportional to the number of AC-SPL cells injected into the site challenged by antigen. The number of AC-SPL cells required for a 50% reduction in DTH-induced swelling is reduced by injecting a cell population enriched for CD8⁺ AC-SPL cells. Immunizing the mice receiving intracameral antigen to the same antigen decreases the RSw50 of AC-SPL cells required to inhibit the expression of DTH.

Conclusions

The results provide the first quantitative demonstration that the numbers of antigen-specific splenic CD8⁺ suppressor T cells are specifically amplified by antigen during an immune response.     

Acquisition of CD80 by human T cells at early stages of activation: functional involvement of CD80 acquisition in T cell to T cell interaction

The interaction between CD28 on T cells and CD80 on APCs intensifies the linkage between TCR and MHC at the site of contact between T cells and APCs. In this study, we demonstrate that during human T cell/human APC interaction, the autologous or allogeneic human CD4(+) T cells become positive for the detection of CD80 at an early stage of activation (24 h). This detection of CD80 is attributable to the acquisition of CD80 from APCs, as opposed to the up-regulation of endogenous CD80, as demonstrated by CD4(+) T cells treated with cyclohexamide. Furthermore, no CD80 mRNA could be detected at 24 h in T cells that had acquired CD80 from APCs. CD80 acquisition by T cells from APCs was enhanced upon TCR engagement. The amount of CD80 acquisition by CD4(+) T cells was shown to be related to the expression of CD80 on APCs. Using soluble fusion proteins (soluble CTLA-4, CD28, and CD80) to block either CD28 on the surface of T cells or CD80 on the surface of APCs, it was demonstrated that CD80 acquisition by T cells is mediated through its receptors, possibly CD28 interaction. Moreover, we demonstrate that T cells that have acquired CD80 have the ability to stimulate other T cells. These data thus suggest that CD80 acquisition by human T cells might play a role in the immunoregulation of T cell responses.