Cacalol Acetate, a Sesquiterpene from Psacalium decompositum, Exerts an Anti-inflammatory Effect through LPS/NF-KB Signaling in Raw 264.7 Macrophages.

Inflammatory diseases remain critical health problems worldwide. The search for anti-inflammatory drugs is a primary activity in the pharmaceutical industry. Cacalol is a sesquiterpene with anti-inflammatory potential that is isolated from Psacalium decompositum, a medicinal plant with several scientific reports supporting its anti-inflammatory activity. Cacalol acetate (CA) is the most stable form. Nevertheless, the participation of CA in the main signaling pathway associated with inflammation is unknown. Our aim was to study the anti-inflammatory effect of CA and to determine its participation in NF-κB signaling. In TPA-induced edema in mice, CA produced 70.3% inhibition. To elucidate the influence of CA on the NF-κB pathway, RAW 264.7 macrophages were pretreated with CA and then stimulated with LPS, evaluating NF-ΚB activation, IKK phosphorylation, IΚB-α, p65, cytokine expression, and COX-2 release and activity. CA inhibited NF-κB activation and its upstream signaling, decreasing phosphorylation IKB-α and p65 levels. CA also reduced expression and secretion of TNF-α, IL-1ß, and IL-6. Additionally, it decreased the activity and expression of COX-2 mRNA. These data support that CA regulates the NF-κB signaling pathway, which might explain, at least in part, its anti-inflammatory effect. CA is a bioactive molecule useful for the development of anti-inflammatory agents with innovative mechanisms of action.

Immunomodulatory role of chloroquine and pyrimethamine in Plasmodium yoelii 17XL infected mice.

Chloroquine (CLQ) and Pyrimethamine (PYR) are used for the treatment of malaria and some autoimmune diseases; although their mechanism of action is only partially understood, their therapeutic effectiveness in the second case has been attributed to their ability to increase apoptosis of T lymphocytes. In view of the potential for immunomodulation during malaria chemotherapy, we investigated the effects of CLQ and PYR treatment on lymphocyte apoptosis and cytokine expression during infection with blood-stage Plasmodium. This work shows that infection of BALB/c mice with Plasmodium yoelii 17XL (Py17XL) reduced apoptosis in spleen cells but when infected mice were treated with CLQ, apoptosis of B and T lymphocytes increased significantly via a Fas-mRNA expression independent mechanism associated with downregulation of Bcl-2 expression, whereas treatment with PYR increased apoptosis to a lesser extent and only in B lymphocytes. CLQ treatment of Py17XL infected mice upregulated tumour necrosis factor-alpha mRNA expression, while PYR treatment increased interferon-gamma mRNA expression. In infected mice, treatment with CLQ downregulated expression of the anti-inflammatory cytokines, interleukin-10 and transforming growth factor-beta (TGF-beta), while PYR treatment upregulated TGF-beta. Thus, in addition to their anti-malarial effects, both drugs modulate the immune response in malaria by increasing apoptosis and modulating the mRNA expression of cytokines involved in parasite elimination and regulation of inflammatory responses.

NF-kappaB translocation and endothelial cell activation is potentiated by macrophage-released signals co-secreted with TNF-alpha and IL-1beta.

OBJECTIVE AND METHODS: Over-expression of the immune response can lead to pathological conditions such as septic shock or chronic inflammation. Endothelial cell activation by pro-inflammatory products of activated macrophages plays a key role in these conditions. Here we examine the response of primary human endothelial cells (HUVEC) to conditioned media (CM) obtained from LPS-activated macrophages. We further characterized the translocation of NF-kappaB in the presence of CM by studying the degradation rate of individual IkappaB isoforms. RESULTS: We show that, as expected, CM induced NF-kappaB translocation, as well as adhesion capacity in HUVEC. We further show that this response is critically dependent on TNF-alpha and IL1beta naturally present in the CM. However, both the amplitude of NF-kappaB translocation and adhesiveness observed with CM were well beyond the saturation levels attained after the sole stimulation with recombinant TNF-alpha and IL-1beta, either separately or together. Our results show that CM induced a faster degradation of the IkappaB-beta and IkappaB-epsilon isoforms than the recombinant cytokines, leading to an enhanced recruitment of NF-kappaB activity. CONCLUSIONS: The above results suggest that the physiological context of factors co-secreted by LPS-activated macrophages enhances TNF-alpha mediated endothelial activation.

Ceramide reproduces late appearance of oxidative stress during TNF-mediated cell death in L929 cells.

Tumor necrosis factor alpha mediated cell death in L929 cells correlates with a late increase in reduction of the superoxide scavenger 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), suggesting an increase in MTT reduction per viable cell. This effect was studied in two TNF-sensitive and in five different TNF-resistant clones. Within 36 hrs TNF promoted a 7-fold increase in the reduction of MTT in TNF-sensitive cells. Exogenous ceramide induced a similar effect prior to cell death. Four of the five TNF-resistant clones were also resistant to ceramide and displayed no increase in MTT reduction with either TNF or ceramide. The remaining TNF-resistant clone was sensitive to ceramide, displaying an increase in MTT reduction. Our results suggest a late increase in superoxide production prior to cellular destruction during TNF and ceramide mediated cell death and support the notion that ceramide can serve as a second messenger for TNF in cell death.