Barrier protective functions of hederacolchiside-E against HMGB1-mediated septic responses.

The role of high mobility group box 1 (HMGB1) has been recognized as important, and suppression of HMGB1 release and restoration of vascular barrier integrity are regarded as potentially promising therapeutic strategies against sepsis. Hederacolchiside-E (HCE), namely 3-O-{α-L-rhamnopyranosyl (1→2)-[ß-D-glucopyranosyl(1→4)]-α-L-arabinopyranosyl}-28-O-[α-L-rhamnopyranosyl (1→4)-ß-D-glucopyranosyl(1→6)-ß-D-glucopyranosyl ester, is a bidesmosidic oleanane saponin first isolated in 1970 from the leaves of Hedera colchica. We tested our hypothesis that HCE inhibits HMGB1-induced vascular hyperpermeability and thereby increases the survival of septic mouse model from suppression of HMGB1 release upon lipopolysaccharide (LPS)-stimulation. In LPS-activated human endothelial cells and a sepsis mouse model by cecal ligation and puncture (CLP), antiseptic activity of HCE was investigated from suppression of vascular permeability, pro-inflammatory proteins, and tissue injury markers. Post-treatment of HCE significantly suppressed HMGB1 release both in LPS-activated human endothelial cells and the CLP-induced sepsis mouse model. HCE inhibited hyperpermeability and alleviated HMGB1-mediated vascular disruptions, and reduced sepsis-related mortality and tissue injury in mice. Our results suggest that reduction of HMGB1 release and septic mortality by HCE may be useful for the drug candidate of sepsis, indicating a possibility of successful repositioning of HCE.

Biapenem reduces sepsis mortality via barrier protective pathways against HMGB1-mediated septic responses.

BACKGROUND: As a late mediator of sepsis, the role of high mobility group box 1 (HMGB1) has been recognized as important, and suppression of HMGB1 release and restoration of vascular barrier integrity are regarded as potentially promising therapeutic strategies for sepsis. For repositioning of previously FDA-approved drugs to develop new therapies for human diseases, screening of chemical compound libraries, biological active, is an efficient method. Our study illustrates an example of drug repositioning of Biapenem (BIPM), a carbapenem antibiotic, for the modulation of HMGB1-induced septic responses. METHODS: We tested our hypothesis that BIPM inhibits HMGB1-induced vascular hyperpermeability and thereby increases the survival of septic mouse model from suppression of HMGB1 release upon lipopolysaccharide (LPS)-stimulation. In LPS-activated human umbilical vein endothelial cells (HUVECs) and a cecal ligation and puncture (CLP)-induced sepsis mouse model, antiseptic activity of BIPM was investigated from suppression of vascular permeability, pro-inflammatory proteins, and markers for tissue injury. RESULTS: BIPM significantly suppressed release of HMGB1 both in LPS-activated HUVECs (upto 60%) and the CLP-induced sepsis mouse model (upto 54%). BIPM inhibited hyperpermeability (upto 59%) and reduced HMGB1-mediated vascular disruptions (upto 62%), mortality (upto 50%), and also tissue injury including lung, liver, and kidney in mice. CONCLUSION: Reduction of HMGB1 release and septic mortality by BIPM (in vitro, from 5 to 15 µM for 6 h; in vivo, from 0.37 to 1.1 mg/kg, 24 h) indicate a possibility of successful repositioning of BIPM for the treatment of sepsis.

Sulforaphane Alleviates Particulate Matter-Induced Oxidative Stress in Human Retinal Pigment Epithelial Cells.

Age-related macular degeneration (AMD) is a leading cause of blindness in the elderly, and oxidative damage to retinal pigment epithelial (RPE) cells plays a major role in the pathogenesis of AMD. Exposure to high levels of atmospheric particulate matter (PM) with an aerodynamic diameter of <2.5 µm (PM2.5) causes respiratory injury, primarily due to oxidative stress. Recently, a large community-based cohort study in the UK reported a positive correlation between PM2.5 exposure and AMD. Sulforaphane (SFN), a natural isothiocyanate found in cruciferous vegetables, has known antioxidant effects. However, the protective effects of SNF in the eye, especially in the context of AMD, have not been evaluated. In the present study, we evaluated the effect of SFN against PM2.5-induced toxicity in human RPE cells (ARPE-19) and elucidated the molecular mechanism of action. Exposure to PM2.5 decreased cell viability in ARPE-19 cells in a time- and dose-dependent manner, potentially due to elevated intracellular reactive oxygen species (ROS). SFN treatment increased ARPE-19 cell viability and decreased PM2.5-induced oxidative stress in a dose-dependent manner. PM2.5-induced downregulation of serum- and glucocorticoid-inducible kinase 1 (SGK1), a cell survival factor, was recovered by SFN. PM2.5 treatment decreased the enzymatic activities of the antioxidant enzymes including superoxide dismutase and catalase, which were restored by SFN treatment. Taken together, these findings suggest that SFN effectively alleviates PM2.5-induced oxidative damage in human ARPE-19 cells via its antioxidant effects, and that SFN can potentially be used as a therapeutic agent for AMD, particularly in cases related to PM2.5 exposure.

Fisetin Suppresses Pulmonary Inflammatory Responses Through Heme Oxygenase-1 Mediated Downregulation of Inducible Nitric Oxide Synthase.

The effects of a mixture of fisetin on cytokine-mediated pulmonary damages have not been studied, despite its known antiviral, neuroprotective, and anti-inflammatory activities. Using lipopolysaccharide (LPS)-activated human pulmonary artery endothelial cells (HPAECs), we determined the effects of fisetin on the induction of heme oxygenase-1 (HO-1), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). In the lung tissue of LPS-treated mice, fisetin was also evaluated for its effect on the regulation of iNOS and tumor necrosis factor (TNF)-α. In LPS-activated HPAECs, fisetin increased nuclear factor erythrocyte 2-related factor 2-antioxidant response element (Nrf2-ARE) reporter activity through the nuclear translocation of Nrf2, and the expression of HO-1, and decreased IL-1ß and iNOS/NO production. In particular, the suppression of iNOS/NO expression by the administration of fisetin was dependent on HO-1. Current findings indicate that the anti-inflammatory activity of fisetin was due to its HO-1 dependent downregulation of p-STAT-1 and nuclear factor kappa B (NF-κB) and the resultant inhibition of iNOS, and also suggest TNF-α as a potential target for HO-1. We propose that administration of fisetin may be a novel approach, ideal for the treatment of inflammatory pulmonary disease.

Inhibitory functions of cardamonin against particulate matter-induced lung injury through TLR2,4-mTOR-autophagy pathways.

Particulate matter with an aerodynamic diameter equal to or less than 2.5 µm (PM2.5) is a form of air pollutant that causes significant lung damage when inhaled. Cardamonin, a flavone found in Alpinia katsumadai Heyata seeds, has been reported to have anti-inflammatory and anticoagulative activity. The aim of this study was to determine the protective effects of cardamonin on PM2.5-induced lung injury. Mice were treated with cardamonin via tail-vein injection 30 min after the intratracheal instillation of PM2.5. The results showed that cardamonin markedly reduced the pathological lung injury, lung wet/dry weight ratio, and hyperpermeability caused by PM2.5. Cardamonin also significantly inhibited PM2.5-induced myeloperoxidase (MPO) activity in lung tissue, decreased the levels of PM2.5-induced inflammatory cytokines and effectively attenuated PM2.5-induced increases in the number of lymphocytes in the bronchoalveolar lavage fluid (BALF). And, cardamonin increased the phosphorylation of mammalian target of rapamycin (mTOR) and dramatically suppressed the PM2.5-stimulated expression of toll-like receptor 2 and 4 (TLR 2,4), MyD88, and the autophagy-related proteins LC3 II and Beclin 1. In conclusion, these findings indicate that cardamonin has a critical anti-inflammatory effect due to its ability to regulate both the TLR2,4-MyD88 and mTOR-autophagy pathways and may thus be a potential therapeutic agent against PM2.5-induced lung injury.