Vasodilatory Effect of Phellinus linteus Extract in Rat Mesenteric Arteries

Phellinus linteus is a well-known medicinal mushroom that is widely used in Asian countries. In several experimental models, Phellinus linteus extracts were reported to have various biological effects, including anti-inflammatory, anti-cancer, hepatoprotective, anti-diabetic, neuroprotective, and anti-angiogenic activity. In the present study, several bioactive compounds, including palmitic acid ethyl ester and linoleic acid, were identified in Phellinus linteus. The intermediate-conductance calcium-activated potassium channel (IKCa) plays an important role in the regulation of the vascular smooth muscle cells’ (VSMCs) contraction and relaxation. The activation of the IKCa channel causes the hyperpolarization and relaxation of VSMCs. To examine whether Phellinus linteus extract causes vasodilation in the mesenteric arteries of rats, we measured the isometric tension using a wire myograph. After the arteries were pre-contracted with U46619 (a thromboxane analogue, 1 µM), Phellinus linteus extract was administered. The Phellinus linteus extract induced vasodilation in a dose-dependent manner, which was independent of the endothelium. To further investigate the mechanism, we used the non-selective K+ channel blocker tetraethylammonium (TEA). TEA significantly abolished Phellinus linteus extract-induced vasodilation. Thus, we tested three different types of K+ channel blockers: iberiotoxin (BKca channel blocker), apamin (SKca channel blocker), and charybdotoxin (IKca channel blocker). Charybdotoxin significantly inhibited Phellinus linteus extract-induced relaxation, while there was no effect from apamin and iberiotoxin. Membrane potential was measured using the voltage-sensitive dye bis-(1,3-dibutylbarbituric acid)-trimethine oxonol (DiBAC4(3)) in the primary isolated vascular smooth muscle cells (VSMCs). We found that the Phellinus linteus extract induced hyperpolarization of VSMCs, which is associated with a reduced phosphorylation level of 20 KDa myosin light chain (MLC20)

Visualization 1: Enhancement of light-matter interaction and photocatalytic efficiency of Au/TiO₂ hybrid nanowires

Real-time view of Au growth along hybrid nanowires driven by local UV illumination. Originally published in Optics Express on 11 July 2016 (oe-24-14-15171

Edge-On MoS₂ Thin Films by Atomic Layer Deposition for Understanding the Interplay between the Active Area and Hydrogen Evolution Reaction

The edge sites of molybdenum disulfide (MoS₂) have been shown to be efficient electrocatalysts for the hydrogen evolution reaction (HER). To utilize these structures, two main strategies have been proposed. The first strategy is to use amorphous structures, which should be beneficial in maximizing the area of the edge-site moieties of MoS₂. However, these structures experience structural instability during HER. The other strategy is nanostructuring, in which, to enhance the resulting HER performance, the exposed surfaces of MoS₂ cannot be inert basal planes. Therefore, MoS₂ may need critical nanocrystallinity to produce the desired facets. Here, we first describe that when atomic layer deposition (ALD) is applied to layered materials such as MoS₂, MoS₂ exhibits the nonideal mode of ALD growth on planar surfaces. As a model system, the ALD of MoCl₅ and H₂S was studied. This nonideality does not allow for the conventional linear relationship between the growth thickness and the number of cycles. Instead, it provides the ability to control the relative ratios of the edge sites and basal planes of MoS₂ to the exposed surfaces. The number of edge sites produced was carefully characterized in terms of the geometric surface area and effective work function and was correlated to the HER performance, including Tafel slopes and exchange current densities. We also discussed how, as a result of the low growth temperature, the incorporation of chlorine impurities affected the electron doping and formation of mixed 2H and 1T phases. Remarkably, the resulting 1T phase was stable even upon thermal annealing at 400 °C. With the simple, planar MoS₂ films, we monitored the resulting catalytic performance, finding current densities of up to 20 mA cm^–2 at −0.3 V versus the reversible hydrogen electrode (RHE), a Tafel slope of 50–60 mV/decade, and an onset potential of 143 mV versus RHE

Spatial Charge Separation in Asymmetric Structure of Au Nanoparticle on TiO₂ Nanotube by Light-Induced Surface Potential Imaging

Both enhancing the excitons’ lifetime and ingeniously controlling the spatial charge transfer are the key to the realization of efficiently photocatalytic and artificially photosynthetic devices. Nanostructured metal/metal-oxide interfaces often exhibit improved energy conversion efficiency. Understanding the surface potential changes of nano-objects under light illumination is crucial in photoelectrochemical cells. Under ultraviolet (UV) illumination, here, we directly observed the charge separation phenomena at the Au-nanoparticle/TiO₂-nanotube interfaces by using Kelvin probe force microscopy. The surface potential maps of TiO₂ nanotubes with and without Au nanoparticles were compared on the effect of different substrates. We observed that in a steady state, approximately 0.3 electron per Au particle of about 4 nm in diameter is effectively charged and consequently screens the surface potential of the underlying TiO₂ nanotubes. Our observations should help design improved photoelectrochemical devices for energy conversion applications

CR6 interacting factor 1 deficiency promotes endothelial inflammation by SIRT1 downregulation

<div><p>Aims</p><p>CR6 interacting factor 1 (CRIF1) deficiency impairs mitochondrial oxidative phosphorylation complexes, contributing to increased mitochondrial and cellular reactive oxygen species (ROS) production. CRIF1 downregulation has also been revealed to decrease sirtuin 1 (SIRT1) expression and impair vascular function. Inhibition of SIRT1 disturbs oxidative energy metabolism and stimulates nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB)-induced inflammation. Therefore, we hypothesized that both CRIF1 deficiency-induced mitochondrial ROS production and SIRT1 reduction play stimulatory roles in vascular inflammation.</p><p>Methods and results</p><p>Plasma levels and mRNA expression of proinflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-1β, and IL-6) were markedly elevated in endothelium-specific CRIF1-knockout mice and CRIF1-silenced endothelial cells, respectively. Moreover, CRIF1 deficiency-induced vascular adhesion molecule-1 (VCAM-1) expression was consistently attenuated by the antioxidant N-acetyl-cysteine and NF-κB inhibitor (BAY11). We next showed that siRNA-mediated CRIF1 downregulation markedly activated NF-κB. SIRT1 overexpression not only rescued CRIF1 deficiency-induced NF-κB activation but also decreased inflammatory cytokines (TNF-α, IL-1β, and IL-6) and VCAM-1 expression levels in endothelial cells.</p><p>Conclusions</p><p>These results strongly suggest that CRIF1 deficiency promotes endothelial cell inflammation by increasing VCAM-1 expression, elevating inflammatory cytokines levels, and activating the transcription factor NF-κB, all of which were inhibited by SIRT1 overexpression.</p></div

CRIF1 deletion stimulated the activation of the NF-κB signaling pathway in HUVECs.

<p>(A) HUVECs were transfected with CRIF1 (50 or 100 pmol) for 48 h, cytosolic and nuclear fractions were isolated, and p65 and IκBα protein levels in the cytoplasm and nucleus were detected by western blotting. (B) p65 and IκBα protein levels were quantified by densitometric analysis. (C) Representative immunofluorescence images of p65 (green) and Hoechst (blue) staining. Scale bars indicate 20 um. (D) NF-κB activity was measured using a dual luciferase reporter gene assay in HUVECs transfected with CRIF1 siRNA (50 and 100 pmol) for 48 h. The graph presents the fold changes in NF-κB activation compared with that in the control. All western blots are representative of three independent experiments. The data are presented as means ± SEM of three independent experiments. *p < 0.05 vs. control cells.</p

SIRT1 mediated CRIF1 deficiency-induced NF-κB activation in HUVECs.

<p>(A) HUVECs were transfected with CRIF1 siRNA (50 and 100 pmol) and SIRT1 siRNA (50 and 100 pmol) for 48 h, and the cytosolic and nuclear fractions were isolated. The protein expression levels of cytosolic p65 and IκBα and nuclear p65 were detected by western blotting. p65 and IκBα protein levels were quantified by densitometric analysis (right panel). (B) HUVECs were infected with β-Gal and SIRT1 adenovirus for 24 h, followed by transfection with CRIF1 siRNA (100 pmol) for 36 h. Cytosolic p65 and IκBα and nuclear p65 protein expression levels were quantified by densitometric analysis (right panel). All western blots are representative of three independent experiments. The data are presented as means ± SEM of three independent experiments. ^#p < 0.05 vs. CRIF1 control cells. *p < 0.05 vs. SIRT1 control cells.</p

SIRT1-mediated CRIF1 deletion-induced inflammatory cytokine and VCAM-1 expression.

<p>(A) HUVECs were infected with β-Gal and SIRT1 adenovirus for 24 h, followed by transfection with CRIF1 (100 pmol) siRNA for 36 h. TNFα, IL-1β, and IL-6 mRNA levels were quantified using qPCR. (B) Whole cell lysates were collected and analyzed for VCAM-1 protein expression by western blotting. VCAM-1 protein levels were quantified by densitometric analysis (right panel). (C) The aorta from WT and CRIF1 EKO mice were infected with β-Gal (control) or SIRT1 adenovirus and incubated for 24 h. Representative immunohistochemical staining images of CD31 (green) and VCAM-1 (red). Scale bars indicate 50 um. Arrowhead indicates VCAM-1 expression. L indicates lumen. Quantified VCAM-1 expression was normalized to the β-Gal (WT) control group (right panel). n = 5 per group. All western blots are representative of three independent experiments (A, B). The data are presented as means ± SEM of three independent experiments. *p < 0.05 vs. control cells or WT mice. ^#p < 0.05 vs. CRIF1 cells or CRIF1 EKO mice.</p

Endothelial CRIF1 deletion elevated inflammatory cytokine and VCAM-1 expression <i>in vivo</i> and <i>in vitro</i>.

<p>(A) Lung endothelial cells were isolated from WT and CRIF1 EKO mice using CD31 and CD45 beads. Endothelial VCAM-1 mRNA and protein expression was determined by western blotting and qPCR, respectively. β-actin was used as the internal control. Densitometric analysis of VCAM-1 protein levels is shown in the middle panel, and the relative mRNA expression of VCAM-1 is shown in the right panel. (B) HUVECs were transfected with CRIF1 siRNA (50 or 100 pmol) for 48 h. TNFα, IL-1β, and IL-6 mRNA levels were quantified by qPCR. (C) ELISAs of TNF-α, IL-1β, and IL-6 expression in the plasma of WT and CRIF1 EKO mice. Data are expressed as the fold change in expression compared with the control group. Western blots are representative of three independent experiments. The data are presented as means ± SEM of three independent experiments. *p < 0.05 vs. control cells.</p