Despite intensive investigation of molecular mechanisms underlying the pathogenesis of sepsis, many aspects of sepsis remain unresolved; this hampers the development of appropriate therapeutics. In the present study, we developed a biologic nanomedicine containing a cationic antimicrobial decapeptide KSLW (KKVVFWVKFK), self-associated with biocompatible and biodegradable PEGylated phospholipid micelles (PLM), and analyzed its efficacy for treating sepsis. KSLW was modified with polyethylene glycol (PEG)-aldehyde or was conjugated with distearoylphosphatidylethanolamine (DSPE) -PEG-aldehyde. We compared the antibacterial and antiseptic effects of PEG-KSLW and PLM-KSLW with those of unmodified KSLW both in vitro and in vivo. We found that the PLM-KSLW improved the survival rate of sepsis mouse models without undesired immune responses, and inhibited lipopolysaccharide (LPS)-induced severe vascular inflammatory responses in human umbilical vein endothelial cells compared with unmodified KSLW or PEG-KSLW. Furthermore, PLM-KSLW dramatically reduced the bacterial count and inhibited bacterial growth. We also found a new role of PLM-KSLW in tightening vascular barrier integrity by binding to the glycine/tyrosine-rich domain of occludin (OCLN). Our results showed that PLM-KSLW had a more effective antiseptic effect than KSLW or PEG-KSLW, possibly because of its high affinity toward OCLN. Moreover, PLM-KSLW could be potentially used to treat severe vascular inflammatory diseases, including sepsis and septic shock.
Zingerone (ZGR), a phenolic alkanone isolated from ginger, has been reported to possess various pharmacological activities. Transforming growth factor β-induced protein (TGFBIp) is an extracellular matrix protein whose expression in several cell types is greatly increased by TGF-β. TGFBIp is released by human umbilical vein endothelial cells and functions as a mediator of experimental sepsis. We hypothesized that ZGR could reduce TGFBIp-mediated severe inflammatory responses in human endothelial cells and mice. Here, we investigated the anti-septic effects and underlying mechanisms of ZGR against TGFBIp-mediated septic responses. ZGR effectively inhibited lipopolysaccharide-induced release of TGFBIp and suppressed TGFBIp-mediated septic responses. In addition, ZGR suppressed TGFBIp-induced sepsis lethality and pulmonary injury. In conclusion, ZGR suppressed TGFBIp-mediated and CLP-induced septic responses. Therefore, ZGR could be a potential therapeutic agent for treatment of various severe vascular inflammatory diseases via inhibition of the TGFBIp signaling pathway.
A certain nucleosomal protein-high mobility group box-1 (HMGB1)-has recently been established as a late mediator of sepsis, with a relatively wide therapeutic window for pharmacological intervention. Pelargonidin (PEL) is a well-known red pigment found in plants; it has important biological activities that are potentially beneficial for human health. In the present study, we investigated whether PEL can modulate HMGB1-mediated inflammatory responses in human umbilical vein endothelial cells (HUVECs) and in mice. The anti-inflammatory activities of PEL were determined by measuring permeability, leukocyte adhesion and migration, and activation of pro-inflammatory proteins in HMGB1-activated HUVECs and mice, as well as the beneficial effects of PEL on survival rate in the mouse sepsis model. The data showed that PEL had effectively inhibited lipopolysaccharide (LPS)-induced release of HMGB1 and suppressed HMGB1-mediated septic responses, such as hyperpermeability, adhesion and migration of leukocytes, and expression of cell adhesion molecules. Furthermore, PEL inhibited the HMGB1-mediated production of tumor necrosis factor alpha (TNF-α) and interleukin 6 (IL-6), as well as the activation of nuclear factor-κB (NF-κB) and extracellular signal-regulated kinases 1 and 2 (ERK1/2). Collectively, these results indicate that PEL could be used to treat various severe vascular inflammatory diseases via the inhibition of the HMGB1 signaling pathway.
Drug repositioning is used to discover drug candidates to treat human diseases, through the application of drugs or compounds that are approved for the treatment of other diseases. This method can significantly reduce the time required and cost of discovering new drug candidates for human diseases. Previous studies have reported pro‐inflammatory responses of endothelial cells to the release of polyphosphate (PolyP). In this study, we examined the anti‐inflammatory responses and mechanisms of methylthiouracil (MTU), which is an antithyroid drug, and its effects on PolyP‐induced septic activities in human umbilical vein endothelial cells (HUVECs) and mice. The survival rates, septic biomarker levels, behaviour of human neutrophils and vascular permeability were determined in PolyP‐activated HUVECs and mice. MTU suppressed the PolyP‐mediated vascular barrier permeability, up‐regulation of inflammatory biomarkers, adhesion/migration of leucocytes, and activation and/or production of nuclear factor‐κB, tumour necrosis factor‐α and interleukin‐6. Furthermore, MTU demonstrated protective effects on PolyP‐mediated lethal death and the levels of the related septic biomarkers. Therefore, these results indicated the therapeutic potential of MTU on various systemic inflammatory diseases, such as sepsis or septic shock.
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