isofraxidin and Inflammation

Platelets have been proved to exacerbate influenza infection and its complications. Inhibition of platelet activation may be a feasible method for preventing severe infection and secondary acute lung injury (ALI). Isofraxidin (IFD) is a natural coumarin isolated from the plants Sarcandra glabra and Siberian ginseng, and exerts anticancer, antioxidant and antiinflammatory effects. In the present study, we examined the therapeutic effects of IFD in ADP- or arachidonic acid (AA)-induced platelet aggregation model and in influenza A virus (IAV)-induced ALI mouse model. The results showed that IFD significantly inhibited platelet aggregation induced by ADP and AA in vitro in a concentration-dependent manner as well as the release of soluble P-selectin and platelet factor 4. Moreover, IFD significantly relieved IAV-induced lung inflammation, reduced the expressions of platelet activation biomarkers (P-selectin and CD61), decreased the serum levels of TNF-α, IL-1β, IL-6 and MIP-2, suppressed peripheral platelet aggregation and prolonged the survival time of infected mice. The western blotting results also demonstrated that IFD reduced the phosphorylation levels of PI3K, AKT and p38 in the activated platelets stimulated by ADP and IAV infection. But IFD did not have any effects on IAV replication. It indicated that IFD ameliorated IAV-induced severe lung damage and lethal infection by suppressing platelet aggregation via regulating PI3K/AKT and MAPK pathways.

Topics: Acute Lung Injury; Alphainfluenzavirus; Animals; Anti-Inflammatory Agents; Coumarins; Cytokines; Dogs; Inflammation; Madin Darby Canine Kidney Cells; Male; Mice, Inbred ICR; Mitogen-Activated Protein Kinases; Orthomyxoviridae Infections; Phosphatidylinositol 3-Kinases; Platelet Aggregation; Platelet Aggregation Inhibitors; Proto-Oncogene Proteins c-akt; Rats, Sprague-Dawley

Inflammation has been demonstrated to be the key factor for intervertebral disc degeneration (IVD), which remains a major public health problem. Isofraxidin is a coumarin compound that possesses strong anti-inflammatory activity. However, the role of isofraxidin in IVD remains unclear. The aim of this study was to evaluate the effects of isofraxidin on inflammatory response in human nucleus pulposus cells (NPCs) exposed to interleukin-1β (IL-1β). The results proved that isofraxidin attenuated the IL-1β-induced significant increases in inflammatory mediators and cytokines including nitric oxide (NO), inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), prostaglandin E2 (PGE2), tumor necrosis factor alpha (TNF-α), and IL-6. Besides, isofraxidin also inhibited the induction effect of IL-1β on matrix metalloproteinases (MMP)-3 and MMP-13. Moreover, the NF-κB activation caused by IL-1β was significantly inhibited by isofraxidin treatment. These findings suggested that isofraxidin alleviates IL-1β-induced inflammation in NPCs. Our work provided an idea that isofraxidin might act as a novel preventive role in IVD.

Topics: Blotting, Western; Cell Survival; Cells, Cultured; Coumarins; Cyclooxygenase 2; Dinoprostone; Enzyme-Linked Immunosorbent Assay; Humans; Inflammation; Interleukin-1beta; Nitric Oxide; Nitric Oxide Synthase Type II; Nucleus Pulposus; Signal Transduction

Osteoarthritis (OA) is the most prevalent disease of knee especially in the aged people. Isofraxidin (IF) is a coumarin compound refined from traditional Chinese medicines with potential anti-inflammatory ability. This study aimed to evaluate protective anti-inflammatory effects of IF in human OA chondrocytes. The chondrocytes were isolated from OA patients and pretreated with IF before treatment with IL-1β. The results showed that IF blocked IL-1β-stimulated production of NO and PGE2. In addition, IF inhibited the expression of COX-2, iNOs, MMP-1, MMP-3, MMP-13, ADAMTS-4 and ADAMTS-5, and increased the levels of aggrecan and collagen-II. Mechanistically, IF suppressed IL-1β-induced IκB-α degradation and NF-κB activation. In conclusion, our results demonstrate that IF inhibits inflammation in OA via the regulation of NF-κB signaling, and suggest that IF may be a potential therapeutic agent for OA.

Topics: ADAMTS4 Protein; Cell Survival; Cells, Cultured; Chondrocytes; Collagen Type II; Coumarins; Dinoprostone; Humans; Inflammation; Interleukin-1beta; Metalloproteases; NF-kappa B; Nitric Oxide Synthase Type II; Osteoarthritis

Isofraxidin (IF), the major bioactive component of Sarcandra glabra, has been reported to be an effective anti-inflammatory compound. In a previous study, we showed that IF acts via the MAPK pathway to produce anti-inflammatory effects, both in vivo and in vitro. However, the effect and mechanism of action of IF on inflammatory cytokines and NF-κB activation in vivo has not been investigated. We therefore aimed to evaluate how IF regulates the production of inflammatory cytokines in vivo by intraperitoneal injection of IF (1, 5 or 15mg/kg) prior to treatment with LPS (1mg/kg, i.p.). Macroscopic, biochemical and histopathological parameters were measured. Treatment with IF prior to LPS challenge decreased mortality rate, body weight loss, organ coefficient and histopathological changes. IF also suppressed the protein expression of NF-κB, levels of NO and IL-6 in serum and production of TNF-α in liver. Our results show that pretreatment with IF increases the survival rate following LPS stimulation in mice. The effect involves regulation of NF-κB signal which, in turn, regulates production of inflammatory cytokine TNF-α, suggesting that IF may have a therapeutic effect against LPS-induced inflammatory disease.

Topics: Animals; Anti-Inflammatory Agents; Coumarins; Heart; Inflammation; Interleukin-12; Interleukin-6; Lipopolysaccharides; Liver; Lung; Macrophages; Male; Mice; Nitric Oxide; Protective Agents; Signal Transduction; Survival Rate; Transcription Factor RelA; Tumor Necrosis Factor-alpha