Inhibition of ERK1/2 by silymarin in mouse mesangial cells.

The present study aimed to show that pro-inflammatory cytokines [tumor necrosis factor (TNF)-α, interferon (IFN)-γ, and interleukin (IL)-1ß] synergistically induce the production of nitric oxide (NO) production in mouse mesangial cells, which play an important role in inflammatory glomerular injury. We also found that co-treatment with cytokines at low doses (TNF-α; 5 ng/ml, IFN-γ; 5 ng/ml, and IL-1ß; 1.25 U/ml) synergistically induced NO production, whereas treatment with each cytokine alone did not increase NO production at doses up to 100 ng/ml or 50 U/ml. Silymarin, a polyphenolic flavonoid isolated from milk thistle (Silybum marianum), attenuates cytokine mixture (TNF-α, IFN-γ, and IL-1ß)-induced NO production. Western blot and RT-PCR analyses showed that silymarin inhibits inducible nitric oxide synthase (iNOS) expression in a dose-dependent manner. Silymarin also inhibited extracellular signal-regulated protein kinase-1 and -2 (ERK1/2) phosphorylation. Collectively, we have demonstrated that silymarin inhibits NO production in mouse mesangial cells, and may act as a useful anti-inflammatory agent.

A Novel FLCN c.1489_1490delTG Mutation that Escapes the Nonsense-Mediated Decay System.

A novel FLCN c.1489_1490delTG (p.Val497Glyfs*22) mutation at the genomic DNA and mRNA levels was identified in a 43-year-old woman with complaining of recurrent primary spontaneous pneumothorax. The aberrant FLCN mRNA escaped the nonsense-mediated decay system (NMD) because of a premature termination code located in an NMD-incompetent region. To the best of our knowledge, this is the first case report of an FLCN mutation escaping the NMD.

Synergistic effects and antibiofilm properties of chimeric peptides against multidrug-resistant Acinetobacter baumannii strains.

The increasing prevalence of drug-resistant pathogens highlights the need to identify novel antibiotics. Here we investigated the efficacies of four new antimicrobial peptides (AMPs) for potential drug development. The antibacterial activities, synergistic effects, and antibiofilm properties of the four chimeric AMPs were tested against Acinetobacter baumannii, an emerging Gram-negative, nosocomial, drug-resistant pathogen. Nineteen A. baumannii strains resistant to ampicillin, cefotaxime, ciprofloxacin, tobramycin, and erythromycin were isolated at a hospital from patients with cholelithiasis. All four peptides exhibited significant antibacterial effects (MIC=3.12 to 12.5 µM) against all 19 strains, whereas five commercial antibiotics showed little or no activity against the same pathogens. An exception was polymyxin, which was effective against all of the strains tested. Each of the peptides showed synergy against one or more strains when administered in combination with cefotaxime, ciprofloxacin, or erythromycin. The peptides also exhibited an ability to prevent biofilm formation, which was not seen with cefotaxime, ciprofloxacin, or erythromycin, though polymyxin also inhibited biofilm formation. Indeed, when administered in combination with ciprofloxacin, the AMP HPMA exerted a potent synergistic effect against A. baumannii biofilm formation. Collectively, our findings indicate that the AMPs tested have no cytotoxicity but possess potent antibacterial and antibiofilm activities and may act synergistically with commercial antibiotics.

Influence of Fimasartan (a Novel AT(1) Receptor Blocker) on Catecholamine Release in the Adrenal Medulla of Spontaneously Hypertensive Rats.

The aim of this study was to determine whether fimasartan, a newly developed AT(1) receptor blocker, can affect the CA release in the isolated perfused model of the adrenal medulla of spontaneously hypertensive rats (SHRs). Fimasartan (5~50 µM) perfused into an adrenal vein for 90 min produced dose- and time-dependently inhibited the CA secretory responses evoked by ACh (5.32 mM), high K(+) (56 mM, a direct membrane depolarizer), DMPP (100 µM) and McN-A-343 (100 µM). Fimasartan failed to affect basal CA output. Furthermore, in adrenal glands loaded with fimasartan (15 µM), the CA secretory responses evoked by Bay-K-8644 (10 µM, an activator of L-type Ca(2+) channels), cyclopiazonic acid (10 µM, an inhibitor of cytoplasmic Ca(2+)-ATPase), and veratridine (100 µM, an activator of Na(+) channels) as well as by angiotensin II (Ang II, 100 nM), were markedly inhibited. In simultaneous presence of fimasartan (15 µM) and L-NAME (30 µM, an inhibitor of NO synthase), the CA secretory responses evoked by ACh, high K(+), DMPP, Ang II, Bay-K-8644, and veratridine was not affected in comparison of data obtained from treatment with fimasartan (15 µM) alone. Also there was no difference in NO release between before and after treatment with fimasartan (15 µM). Collectively, these experimental results suggest that fimasartan inhibits the CA secretion evoked by Ang II, and cholinergic stimulation (both nicotininc and muscarinic receptors) as well as by membrane depolarization from the rat adrenal medulla. It seems that this inhibitory effect of fimasartan may be mediated by blocking the influx of both Na(+) and Ca(2+) through their ion channels into the rat adrenomedullary chromaffin cells as well as by inhibiting the Ca(2+) release from the cytoplasmic calcium store, which is relevant to AT(1) receptor blockade without NO release.

Synergistic Induction of iNOS by IFN-γ and Glycoprotein Isolated from Dioscorea batatas.

Dioscorea species continue to be used in traditional Chinese medicine, and represent a major source of steroid precursors for conventional medicine. In the previous study, We isolated glycoprotein (GDB) from Dioscorea batatas, characterized, and demonstrated immunostimulating activity in C57BL/6 mice. The aim of this study was to investigate the mechanism whereby GDB activates macrophages. Macrophages activation by GDB was investigated by analyzing the effects of GDB on nitric oxide (NO) production, iNOS expression, mitogen activated protein kinase (MAPK) phosphorylation, and transcription factor activation. In the presence of IFN-γ, GDB strongly stimulated macrophages to express iNOS and produce NO. Furthermore, the activation of p38 was synergistically induced by GDB plus IFN-γ , but SB203580 (a p38 inhibitor) inhibited GDB plus IFN-γ-induced p38 activation. This study indicates that GDB is an important activator of macrophages. Furthermore, due to the critical role that macrophage activation plays in innate immune response, the activation effects of GDB on macrophages suggest that GDB may be a useful immunopotentiating agent.

Inhibition of p65 Nuclear Translocation by Baicalein.

We demonstrate that baicalein, a bioactive flavonoid originally isolated from Scutellaria baicalensis, inhibits LPS-induced expression of iNOS gene in RAW 264.7 cells. Treatment of peritoneal macrophages and RAW 264.7 cells with baicalein inhibited LPS-stimulated nitric oxide production in a dose-related manner. Immunohistochemical staining of iNOS and RT-PCR analysis showed that the decrease of NO was due to the inhibition of iNOS gene expression in RAW 264.7 cells. Immunostaining of p65, EMSA, and reporter gene assay showed that baicalein inhibited NF-κB nuclear translocation, DNA binding, and transcriptional activation, respectively. Collectively, these series of experiments indicate that baicalein inhibits iNOS gene expression by blocking NF-κB nuclear translocation. Due to the critical role that NO release plays in mediating inflammatory responses, the inhibitory effects of baicalein on iNOS suggest that baicalein may represent a useful anti-inflammatory agent.

KIOM-79 inhibits LPS-induced iNOS gene expression by blocking NF-kappaB/Rel and p38 kinase activation in murine macrophages.

We demonstrate that KIOM-79, combined extracts obtained from Magnolia officinalis, Pueraria lobata, Glycyrrhiza uralensis, and Euphorbia pekinensis, inhibits LPS-induced expression of iNOS gene in RAW 264.7 cells. Treatment of RAW 264.7 cells with KIOM-79 inhibited LPS-stimulated nitric oxide production in a dose-related manner. Immunohisto-chemical staining of iNOS and RT-PCR analysis showed that the decrease of NO was due to the inhibition of iNOS gene expression. Immunostaining of p65, EMSA, and reporter gene assay showed that KIOM-79 inhibited NF-kappa/Rel nuclear translocation, DNA binding, and transcriptional activation, respectively. Western immunoblot analysis of p38 kinase showed KIOM-79 significantly inhibited the phosphoylation of p38 kinase which is important in the regulation of iNOS gene expression. Collectively, this series of experiments indicates that KIOM inhibits iNOS gene expression by blocking NF-kappa/Rel and p38 kinase signaling. Due to the critical role that NO release plays in mediating inflammatory responses, the inhibitory effects of KIOM-79 on iNOS suggest that KIOM-79 may represent a useful anti-inflammatory agent.