Circulating Microvesicle-Associated Inducible Nitric Oxide Synthase Is a Novel Therapeutic Target to Treat Sepsis: Current Status and Future Considerations.

To determine whether mitigating the harmful effects of circulating microvesicle-associated inducible nitric oxide (MV-A iNOS) in vivo increases the survival of challenged mice in three different mouse models of sepsis, the ability of anti-MV-A iNOS monoclonal antibodies (mAbs) to rescue challenged mice was assessed using three different mouse models of sepsis. The vivarium of a research laboratory Balb/c mice were challenged with an LD80 dose of either lipopolysaccharide (LPS/endotoxin), TNFα, or MV-A iNOS and then treated at various times after the challenge with saline as control or with an anti-MV-A iNOS mAb as a potential immunotherapeutic to treat sepsis. Each group of mice was checked daily for survivors, and Kaplan-Meier survival curves were constructed. Five different murine anti-MV-A iNOS mAbs from our panel of 24 murine anti-MV-A iNOS mAbs were found to rescue some of the challenged mice. All five murine mAbs were used to genetically engineer humanized anti-MV-A iNOS mAbs by inserting the murine complementarity-determining regions (CDRs) into a human IgG1,kappa scaffold and expressing the humanized mAbs in CHO cells. Three humanized anti-MV-A iNOS mAbs were effective at rescuing mice from sepsis in three different animal models of sepsis. The effectiveness of the treatment was both time- and dose-dependent. Humanized anti-MV-A iNOS rHJ mAb could rescue up to 80% of the challenged animals if administered early and at a high dose. Our conclusions are that MV-A iNOS is a novel therapeutic target to treat sepsis; anti-MV-A iNOS mAbs can mitigate the harmful effects of MV-A iNOS; the neutralizing mAb's efficacy is both time- and dose-dependent; and a specifically targeted immunotherapeutic for MV-A iNOS could potentially save tens of thousands of lives annually and could result in improved antibiotic stewardship.

Isodeoxyelephantopin, a sesquiterpene lactone from Elephantopus scaber Linn., inhibits pro-inflammatory mediators' production through both NF-κB and AP-1 pathways in LPS-activated macrophages.

Isodeoxyelephantopin (IDET) has been identified as an anti-tumor natural constituent whose anti-tumor activity and mechanism have been widely investigated. Since the occurrence and development of cancer usually accompany with inflammation, and tumor signaling shares many components with inflammation signaling, the agents with anti-tumor activity are likely to possess anti-inflammation potential. Thus, the current study aims to demonstrate the anti-inflammatory activity along with the underlying mechanism of IDET in lipopolysaccharide (LPS)-primed macrophages. By using Griess method and ELISA, we found that in both bone marrow derived macrophages and alveolar macrophage cell line, IDET, at relatively low concentrations (0.75, 1.5 and 3 µM), could inhibit LPS-induced expression of various pro-inflammatory mediators including nitric oxide (NO) generated by inducible nitric oxide synthase (iNOS), interleukin (IL)-6, monocyte chemotactic protein-1 (MCP-1) and IL-1ß. Meanwhile, in activated MH-S cells, the inhibitory action of IDET on mRNA expression levels of these cytokines was also detected using qPCR. Mechanistically, the effects of IDET on two key inflammatory signalings, nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) pathways, were determined in LPS-activated MH-S cells by reporter gene along with western blot assays. On the one hand, IDET suppressed NF-κB signaling via down-regulating phosphorylation and degradation of inhibitor of NF-κB (IκB)-α and the subsequent p65 translocation. On the other hand, IDET dampened AP-1 signaling through attenuating phosphorylation of both c-jun N-terminal kinase 1/2 (JNK1/2) and extracellular signal regulated kinase 1/2 (ERK1/2). Our study indicates that IDET might be a promising constituent from the anti-inflammatory herb Elephantopus scaber Linn. in mitigating inflammatory conditions, especially respiratory inflammation.