Background and purpose: In this study we examined the effect of the natural product cardamonin, upon lipopolysaccharide (LPS)‐induced inflammatory gene expression in order to attempt to pinpoint the mechanism of action.Experimental approaches: Cardamonin was isolated from the Greek plantA. absinthiumL. Its effects were assessed on LPS‐induced nitrite release and iNOS and COX‐2 protein expression in two macrophage cell lines. Western blotting was used to investigate its effects on phosphorylation of the mitogen activated protein (MAP) kinases, ERK, JNK and p38 MAP kinase, and activation of the NFκB pathway, at the level of IκBαdegradation and phosphorylation of NFκB. Also its effects on NFκB and GAS/GAF‐DNA binding were assessed by EMSA.Key results: Cardamonin concentration‐dependently inhibited both NO release and iNOS expression but had no effect on COX‐2 expression. It did not affect phosphorylation of the MAP kinases, degradation of IκBαor phosphorylation of NFκB. However, it inhibited NFκB DNA‐binding in both LPS‐stimulated cells and nuclear extracts of the cells (in vitro). It also inhibited IFNγ‐stimulated iNOS induction and GAS/GAF‐DNA binding.Conclusions and Implications: These results show that the inhibitory effect of cardamonin on LPS‐induced iNOS induction is not mediated via effects on the initial activation of the NFκB or MAP kinase pathways but is due to a direct effect on transcription factor binding to DNA. However, although some selectivity in cardamonin's action is implicated by its inability to affect COX‐2 expression, its exact mechanism(s) of action has yet to be identified.British Journal of Pharmacology(2006)149, 188–198. doi:10.1038/sj.bjp.0706856

The role of progesterone in modulating dendritic cell (DC) function following stimulation of different TLRs is relatively unknown. We compared the ability of progesterone to modulate murine bone marrow-derived DC cytokine production (IL-6 and IL-12) and costimulatory molecule expression (CD40, CD80, and CD86) induced by either TLR3 or TLR4 ligation and determined whether activity was via the progesterone receptor (PR) or glucocorticoid receptor (GR) by comparative studies with the PR-specific agonist norgestrel and the GR agonist dexamethasone. Progesterone was found to downregulate, albeit with different sensitivities, both TLR3- and TLR4-induced IL-6 production entirely via the GR, but IL-12p40 production via either the GR or PR. Of particular significance was that progesterone was able to significantly inhibit TLR3- but not TLR4-induced CD40 expression in bone marrow-derived DCs. Stimulation of the PR (with progesterone and norgestrel) by pretreatment of DCs was found to sustain IFN regulatory factor-3 phosphorylation following TLR3 ligation, but not TLR4 ligation. Overall, these studies demonstrate that progesterone can differentially regulate the signaling pathways employed by TLR3 and TLR4 agonists to affect costimulatory molecule expression and cytokine production.

There is limited evidence that inhibition of the activity of the cytosolic cysteine protease calpain reduces ischemia/reperfusion injury. The multiple organ injury associated with hemorrhagic shock is due at least in part to ischemia (during hemorrhage) and reperfusion (during resuscitation) of target organs. Here we investigate the effects of calpain inhibitor I on the organ injury (kidney, liver, pancreas, lung, intestine) and dysfunction (kidney) associated with hemorrhagic shock in the anesthetized rat. Hemorrhage and resuscitation with shed blood resulted in an increase in calpain activity (heart), activation of NF‐κB (kidney), expression of iNOS and COX‐2 (kidney), and the development of multiple organ injury and dysfunction, all of which were attenuated by calpain inhibitor I (10 mg/kg i.p.), administered 30 min prior to hemorrhage. Chymostatin, a serine protease inhibitor that does not prevent the activation of NF‐κB, had no effect on the organ injury/failure caused by hemorrhagic shock. Pretreatment (for 1 h) of murine macrophages or rat aortic smooth muscle cells (activated with endotoxin) with calpain inhibitor I attenuated the binding of activated NF‐κB to DNA and the degradation of IκBα, IKBβ, and IκBε. Selective inhibition of iNOS activity with L‐NIL reduced the circulatory failure and liver injury, while selective inhibition of COX‐2 activity with SC58635 reduced the renal dysfunction and liver injury caused by hemorrhagic shock. Thus, we provide evidence that the mechanisms by which calpain inhibitor I reduces the circulatory failure as well as the organ injury and dysfunction in hemorrhagic shock include 1 ) inhibition of calpain activity, 2 ) inhibition of the activation of NF‐κB and thus prevention of the expression of NFκB‐dependent genes, 3 ) prevention of the expression of iNOS, and 4 ) prevention of the expression of COX‐2. Inhibition of calpain activity may represent a novel therapeutic approach for the therapy of hemorrhagic shock.—McDonald, M. C., Mota‐Filipe, H., Paul, A., Cuzzocrea, S., Abdelrahman, M., Harwood, S., Plevin, R., Chatterjee, P. K., Yaqoob, M. M., Thiemermann, C. Calpain inhibitor I reduces the activation of nuclear factor‐κB and organ injury/dysfunction in hemorrhagic shock. FASEB J. 15, 171–186 (2001)