Bronchoalveolar cytokine profile differentiates Pulmonary Langerhans cell histiocytosis patients from other smoking-related interstitial lung diseases.

BACKGROUND: Pulmonary Langerhans cell histiocytosis (PLCH) is a rare interstitial lung disease (ILD) associated with smoking, whose definitive diagnosis requires the exclusion of other forms of ILD and a compatible surgical lung biopsy. Bronchoalveolar lavage (BAL) is commonly proposed for the diagnosis of ILD, including PLCH, but the diagnostic value of this technique is limited. Here, we have analyzed the levels of a panel of cytokines and chemokines in BAL from PLCH patients, in order to identify a distinct immune profile to discriminate PLCH from other smoking related-ILD (SR-ILD), and comparing the results with idiopathic pulmonary fibrosis (IPF) as another disease in which smoking is considered a risk factor. METHODS: BAL samples were collected from thirty-six patients with different ILD, including seven patients with PLCH, sixteen with SR-ILD and thirteen with IPF. Inflammatory profiles were analyzed using the Human Cytokine Membrane Antibody Array. Principal component analysis (PCA) was performed to reduce dimensionality and protein-protein interaction (PPI) network analysis using STRING 11.5 database were conducted. Finally, Random forest (RF) method was used to build a prediction model. RESULTS: We have found significant differences (p < 0.05) on thirty-two cytokines/chemokines when comparing BAL from PLCH patients with at least one of the other ILD. Four main groups of similarly regulated cytokines were established, identifying distinct sets of markers for each cluster. Exploratory analysis using PCA (principal component analysis) showed clustering and separation of patients, with the two first components capturing 69.69% of the total variance. Levels of TARC/CCL17, leptin, oncostatin M (OSM) and IP-10/CXCL10 were associated with lung function parameters, showing positive correlation with FVC. Finally, random forest (RF) algorithm demonstrates that PLCH patients can be differentiated from the other ILDs based solely on inflammatory profile (accuracy 96.25%). CONCLUSIONS: Our results show that patients with PLCH exhibit a distinct BAL immune profile to SR-ILD and IPF. PCA analysis and RF model identify a specific immune profile useful for discriminating PLCH.

Synthesis of Quinoline and Dihydroquinoline Embelin Derivatives as Cardioprotective Agents.

A set of new dihydroquinoline embelin derivatives was obtained from the reaction of the natural benzoquinone embelin (1) with anilines and aromatic aldehydes in the presence of AgOTf. The synthesis of these compounds involves the formation of a Knoevenagel adduct, followed by nucleophilic addition of aniline and subsequent electrocyclic ring closure. The scope of the reaction regarding the aldehydes and anilines was determined. Quinoline derivatives were also obtained from the corresponding dihydroquinolines under oxidation with DDQ. The cardioprotective activity of the synthesized compounds was screened using a doxorubicin-induced cardiotoxicity model in H9c2 cardiomyocytes. Some structure-activity relationships were outlined, and the best activities were achieved with quinoline-embelin derivatives having a 4-nitrophenyl group attached at the pyridine ring. The obtained results indicated that embelin derivatives 4i, 6a, 6d, 6k, and 6m could have potential as cardioprotective agents, as they attenuated a DOX-induced cardiotoxicity effect acting on oxidative stress and apoptosis.

Phenolic and quinone methide nor-triterpenes as selective NLRP3 inflammasome inhibitors.

Dysregulated inflammasome activity, particularly of the NLRP3 inflammasome, is associated with the development of several inflammatory diseases. The study of molecules directly targeting NLRP3 is an emerging field in the discovery of new therapeutic compounds for the treatment of inflammatory disorders. Friedelane triterpenes are biologically active phytochemicals having a wide range of activities including anti-inflammatory effects. In this work, we evaluated the potential anti-inflammatory activity of phenolic and quinonemethide nor-triterpenes (1-11) isolated from Maytenus retusa and some semisynthetic derivatives (12-16) through inhibition of the NLRP3 inflammasome in macrophages. Among them, we found that triterpenes 6 and 14 were the most potent, showing markedly reduced caspase-1 activity, IL-1ß secretion (IC50 = 1.15 µM and 0.19 µM, respectively), and pyroptosis (IC50 = 2.21 µM and 0.13 µM, respectively). Further characterization confirmed their selective inhibition of NLRP3 inflammasome in both canonical and non-canonical activation pathways with no effects on AIM2 or NLRC4 inflammasome activation.

Labdane conjugates protect cardiomyocytes from doxorubicin-induced cardiotoxicity.

The cardiovascular side effects associated with doxorubicin (DOX), a wide spectrum anticancer drug, have limited its clinical application. Therefore, to explore novel strategies with cardioprotective effects, a series of new labdane conjugates were prepared (6a-6c and 8a-8d) from the natural diterpene labdanodiol (1). These hybrid compounds contain anti-inflammatory privileged structures such as naphthalimide, naphthoquinone, and furanonaphthoquinone. Biological activity of these conjugates against DOX-induced cardiotoxicity was tested in vitro and the potential molecular mechanisms of protective effects were explored in H9c2 cardiomyocytes. Three compounds 6c, 8a, and 8b significantly improved cardiomyocyte survival, via inhibition of reactive oxygen species-mediated mitogen-activated protein kinase signaling pathways (extracellular signal-regulated kinase and c-Jun N-terminal kinase) and autophagy mediated by Akt activation. Some structure-activity relationships were outlined, and the best activity was achieved with the labdane-furonaphthoquinone conjugate 8a having an N-cyclohexyl substituent. The findings of this study pave the way for further investigations to obtain more compounds with potential cardioprotective activity.

Dehydrohispanolone Derivatives Attenuate the Inflammatory Response through the Modulation of Inflammasome Activation.

The NLRP3 inflammasome plays a critical role in inflammation-mediated human diseases and represents a promising drug target for novel anti-inflammatory therapies. Hispanolone is a labdane diterpenoid isolated from the aerial parts of Ballota species. This diterpenoid and some derivatives have demonstrated anti-inflammatory effects in classical inflammatory pathways. In the present study, a series of dehydrohispanolone derivatives (1-19) was synthesized, and their anti-inflammatory activities toward NLRP3 inflammasome activation were evaluated. The structures of the dehydrohispanolone analogues produced were elucidated by NMR spectroscopy and mass spectrometry. Four derivatives significantly inhibited IL-1ß secretion, with 15 and 18 being the most active (IC50 = 18.7 and 13.8 µM, respectively). Analysis of IL-1ß and caspase-1 expression revealed that the new diterpenoids 15 and 18 are selective inhibitors of the NLRP3 inflammasome, reinforcing the previously demonstrated anti-inflammatory properties of hispanolone derivatives.

Semisynthesis and Inhibitory Effects of Solidagenone Derivatives on TLR-Mediated Inflammatory Responses.

A series of nine derivatives (2⁻10) were prepared from the diterpene solidagenone (1) and their structures were elucidated by means of spectroscopic studies. Their ability to inhibit inflammatory responses elicited in peritoneal macrophages by TLR ligands was investigated. Compounds 5 and 6 showed significant anti-inflammatory effects, as they inhibited the protein expression of nitric oxide synthase (NOS-2), cyclooxygenase-2 (COX-2), and cytokine production (TNF-α, IL-6, and IL-12) induced by the ligand of TLR4, lipopolysaccharide (LPS), acting at the transcriptional level. Some structure⁻activity relationships were outlined. Compound 5 was selected as a representative compound and molecular mechanisms involved in its biological activity were investigated. Inhibition of NF-κB and p38 signaling seems to be involved in the mechanism of action of compound 5. In addition, this compound also inhibited inflammatory responses mediated by ligands of TLR2 and TLR3 receptors. To rationalize the obtained results, molecular docking and molecular dynamic studies were carried out on TLR4. All these data indicate that solidagenone derivative 5 might be used for the design of new anti-inflammatory agents.

8,9-Dehydrohispanolone-15,16-lactol diterpene prevents LPS-triggered inflammatory responses by inhibiting endothelial activation.

Endothelial activation contributes to lung inflammatory disorders by inducing leucocyte recruitment to pulmonary parenchyma. Consequently, vascular-targeted therapies constitute promising strategies for the treatment of inflammatory pathologies. In the present study, we evaluated the effect of 8,9-dehydrohispanolone-15,16-lactol diterpene (DT) on lung endothelium during inflammation. Lung endothelial cells pre-treated with DT and activated with lipopolysaccharide (LPS) or tumour necrosis factor-α (TNF-α) exhibited reduced expression of the pro-inflammatory cytokines Cxcl10, Ccl5 and Cxcl1, whereas the anti-inflammatory molecules IL1r2 and IL-10 were induced. Consistent with this result, DT pre-treatment inhibited nuclear factor κB (NF-κB) nuclear translocation, by interfering with IκBα phosphorylation, and consequently NF-κB transcriptional activity in endothelium activated by LPS or TNF-α. Furthermore, DT, probably through p38 signalling, induced transcriptional activation of genes containing activator protein 1 (AP-1)-binding elements. Inhibition of p38 prevented IL1r2 mRNA expression in endothelium incubated with DT alone or in combination with LPS or TNF-α. Accordingly, conditioned medium (CM) from these cells failed to stimulate leucocytes as measured by a reduction in adhesive ability of the leucocyte cell line J774 to fibronectin (FN). Additionally, DT reduced the expression of the endothelial adhesion molecules E-selectin, vascular cell adhesion molecule 1 (VCAM-1) and intercellular adhesion molecule 1 (ICAM-1) after activation. Similarly, expression of VCAM-1 and ICAM-1 molecules on the lung endothelial layer of C57/BL6 mice pre-treated with DT and challenged with LPS were unchanged. Finally, inhibition of vascular adhesion molecule expression by DT decreased the interaction of J774 cells with lung endothelial cells in an inflammatory environment. Our findings establish DT as a novel endothelial inhibitor for the treatment of inflammatory-related diseases triggered by Gram-negative bacteria or by the associated cytokine TNF-α.

Critical role of p38 MAPK in IL-4-induced alternative activation of peritoneal macrophages.

Alternative activation of macrophages plays an important role in a range of physiological and pathological processes. This alternative phenotype, also known as M2 macrophages, is induced by type 2 cytokines such as IL-4. The binding of IL-4 to its receptor leads to activation of two major signaling pathways: STAT-6 and PI3K. However, recent studies have described that p38 MAPK might play a role in IL-4-dependent signaling in some cells, although its role in macrophages is still controversial. In this study, we investigated whether p38 MAPK plays a role in the polarization of macrophages in mice. Our results reveal that IL-4 induces phosphorylation of p38 MAPK in thioglycollate-elicited murine peritoneal macrophages, in addition to STAT-6 and PI3K activation. Furthermore, p38 MAPK inactivation, by gene silencing or pharmacological inhibition, suppressed IL-4-induced typical M2 markers, indicating the involvement of p38 MAPK in the signaling of IL-4 leading to M2-macrophage polarization. Moreover, p38 MAPK inhibition blocked phosphorylation of STAT-6 and Akt, suggesting that p38 MAPK is upstream of these signaling pathways. Finally, we show that in an in vivo model of chitin-induced M2 polarization, p38 MAPK inhibition also diminished activation of M2 markers. Taken together, our data establish a new role for p38 MAPK during IL-4-induced alternative activation of macrophages.

Chemokines and relapses in childhood acute lymphoblastic leukemia: A role in migration and in resistance to antileukemic drugs.

We studied whether chemokines may have a role in relapses in childhood acute lymphoblastic leukemia (ALL). We compared the levels of chemokine receptors in marrow samples from 82 children with ALL at diagnosis versus 15 at relapses, and quantified the levels of chemokines in central system fluid (CSF) samples. The functional role of specific chemokines was studied in vitro and in vivo. The expression of some chemokine receptors was upregulated upon leukemic relapse, both in B- and in T-ALL, and in cases of medullary and extramedullary involvement. CXCL10 induced chemotaxis in leukemic cell lines and in primary leukemic cells, depending upon the levels of CXCR3 expression. CXCL10 specifically diminished chemotherapy-induced apoptosis on ALL cells expressing CXCR3, partially inhibiting caspase activation and maintaining the levels of the antiapoptotic protein Bcl-2. Finally, immunodeficient mice engrafted with CXCR3-expressing human leukemic cells showed decreased infiltration of marrow, spleen, and CNS after receiving a CXCR3-antagonist molecule. CXCR3 signaling in ALL may have a dual function: chemotactic for the localisation of leukemic blasts in specific niches, and it may also confer resistance to chemotherapy, enhancing the chances for relapses.

α-Hispanolol sensitizes hepatocellular carcinoma cells to TRAIL-induced apoptosis via death receptor up-regulation.

Hispanolone derivatives have been previously described as anti-inflammatory and antitumoral agents. However, their effects on overcoming Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) resistance remain to be elucidated. In this study, we analyzed the cytotoxic effects of the synthetic hispanolone derivative α-hispanolol (α-H) in several tumor cell lines, and we evaluated the induction of apoptosis, as well as the TRAIL-sensitizing potential of α-H in the hepatocellular carcinoma cell line HepG2. Our data show that α-H decreased cell viability in a dose-dependent manner in HeLa, MDA-MB231, U87 and HepG2 cell lines, with a more prominent effect in HepG2 cells. Interestingly, α-H had no effect on non-tumoral cells. α-H induced activation of caspase-8 and caspase-9 and also increased levels of the proapoptotic protein Bax, decreasing antiapoptotic proteins (Bcl-2, X-IAP and IAP-1) in HepG2 cells. Specific inhibition of caspase-8 abrogated the cascade of caspase activation, suggesting that the extrinsic pathway has a critical role in the apoptotic events induced by α-H. Furthermore, combined treatment of α-H with TRAIL enhanced apoptosis in HepG2 cells, activating caspase-8 and caspase-9. This correlated with up-regulation of both the TRAIL death receptor DR4 and DR5. DR4 or DR5 neutralizing antibodies abolished the effect of α-H on TRAIL-induced apoptosis, suggesting that sensitization was mediated through the death receptor pathway. Our results demonstrate that α-H induced apoptosis in the human hepatocellular carcinoma cell line HepG2 through activation of caspases and induction of the death receptor pathway. In addition, we describe a novel function of α-H as a sensitizer on TRAIL-induced apoptotic cell death in HepG2 cells.

Biological evaluation of angular disubstituted naphthoimidazoles as anti-inflammatory agents.

A series of naphthoimidazoles derivatives (3a-3f) were tested for potential anti-inflammatory activity on lipopolysaccharide (LPS)-treated macrophages. Naphthoimidazole 3e exhibited significant inhibitory effects on nitric oxide (NO) production (IC50 <10µM) and decreased the expression of nitric oxide synthase-2 (NOS-2) and cycloxygenase-2 (COX-2) enzymes. It also inhibited the activation of transcription factor NF-κB. Naphthoimidazole 3e might represent a starting point for the synthesis of new anti-inflammatory naphthoimidazoles derivatives.

IL10 released by a new inflammation-regulated lentiviral system efficiently attenuates zymosan-induced arthritis.

Administration of anti-inflammatory cytokines is a common therapeutic strategy in chronic inflammatory diseases. Gene therapy is an efficient method for delivering therapeutic molecules to target cells. Expression of the cell adhesion molecule E-selectin (ESEL), which is expressed in the early stages of inflammation, is controlled by proinflammatory cytokines, making its promoter a good candidate for the design of inflammation-regulated gene therapy vectors. This study describes an ESEL promoter (ESELp)-based lentiviral vector (LV) that drives localized transgene expression during inflammation. Mouse matrigel plug assays with ESELp-transduced endothelial cells showed that systemic lipopolysaccharide (LPS) administration selectively induces ESELp-controlled luciferase expression in vivo. Inflammation-specific induction was confirmed in a mouse model of arthritis, showing that this LV is repeatedly induced early in acute inflammation episodes and is downregulated during remission. Moreover, the local acute inflammatory response in this animal model was efficiently blocked by expression of the anti-inflammatory cytokine interleukin-10 (IL10) driven by our LV system. This inflammation-regulated expression system has potential application in the design of new strategies for the local treatment of chronic inflammatory diseases such as cardiovascular and autoimmune diseases.

Synthesis and cytotoxic activity of metallic complexes of lawsone.

In the present study, a series of metallic complexes of the 1,4-naphthoquinone lawsone (2-6) were synthesized and evaluated for potential cytotoxicity in a mouse leukemic macrophagic RAW 264.7 cell line. Cell viability was determined by the MTT assay. Significant growth inhibition was observed for the copper complex (4) with an IC(50) value of 2.5 µM. This compound was selected for further evaluation of cytotoxic activity on several human cancer cells including HT-29 (human colorectal adenocarcinoma), HepG2 (human hepatocellular carcinoma) and HeLa, (human cervical adenocarcinoma cells). Significant cell viability decrease was also observed in HepG2 cells. The apoptotic potential of this complex was evaluated in these cells. Compound 4 induced apoptosis by a mechanism that involves the activation of caspases 3, 8 and 9 and modulation of apoptotic-related proteins such as Bax, Bad, and p53. These results indicate that metal complexes of lawsone derivatives, in particular compound 4, might be used for the design of new antitumoral agents.

The tumor suppressor ARF regulates innate immune responses in mice.

The innate immune system is the first line of defense against invading organisms, and TLRs are the main sensors of microbial components, initiating signaling pathways that induce the production of proinflammatory cytokines and type I IFNs. An antiviral action for the tumor suppressor alternative reading frame (ARF) has been reported; however, the precise role of ARF in innate immunity is unknown. In this study, we show that ARF plays an important role in regulation of inflammatory responses. In peritoneal macrophages and bone marrow-derived macrophages from ARF-deficient animals, the induction of proinflammatory cytokines and chemokines by TLR ligands was severely impaired. The altered responses of ARF(-/-) cells to TLR ligands result from aberrant activation of intracellular signaling molecules including MAPKs, IκBα degradation, and NF-κB activation. Additionally, animals lacking ARF were resistant to LPS-induced endotoxic shock. This impaired activation of inflammation in ARF(-/-) mice was not restricted to TLRs, as it was also shown in response to non-TLR signaling pathways. Thus, ARF(-/-) mice were also unable to trigger a proper inflammatory response in experimental peritonitis or in 12-O-tetradecanoylphorbol-13-acetate-induced edema. Overexpression of ARF, but not its downstream target p53, rescued the ARF-deficient phenotype, increasing TLR4 levels and restoring inflammatory reaction. An increase in the E2F1 protein levels observed in ARF(-/-) macrophages at basal condition and after LPS stimulation may be involved in the impaired response in this system, as E2F1 has been described as an inflammatory suppressor. These results indicate that tumor suppressor ARF is a new regulator of inflammatory cell signaling.

Visualization of Lipid Droplets in the Alveolar Macrophage Cell Line MH-S with Live-cell Imaging by 3D Holotomographic Microscopy (Nanolive).

Lipid droplets (LD), triglycerides and sterol esters among them, are well known for their capacity as lipid storage organelles. Recently, they have emerged as critical cytoplasmic structures involved in numerous biological functions. LD storage is generated de novo by the cell and provides an energy reserve, lipid precursors, and cell protection. Moreover, LD accumulation can be observed in some pathologies as obesity, atherosclerosis, or lung diseases. Fluorescence imaging techniques are the most widely used techniques to visualize cellular compartments in live cells, including LD. Nevertheless, presence of fluorophores can damage subcellular components and induce cytotoxicity, or even alter the dynamics of the organelles. As an alternative to fluorescence microscopy, label-free techniques such as stimulated Raman scattering and coherent anti-stokes Raman scattering microscopy offer a solution to avoid the undesirable effects caused by dyes and fluorescent proteins, but are expensive and complex. Here, we describe a label-free method using live-cell imaging by 3D holotomographic microscopy (Nanolive) to visualize LD accumulation in the MH-S alveolar macrophage cell line after treatment with oleic acid, a monounsaturated fatty acid that promotes lipid accumulation.

Labdanolic acid methyl ester (LAME) exerts anti-inflammatory effects through inhibition of TAK-1 activation.

Labdane derivatives obtained from the diterpenoid labdanediol suppressed NO and PGE(2) production in LPS-stimulated RAW 264.7 macrophages. However, mechanisms involved in these inhibitory effects are not elucidated. In this study, we investigated the signaling pathways involved in the anti-inflammatory effects of labdanolic acid methyl ester (LAME) in peritoneal macrophages and examined its therapeutic effect in a mouse endotoxic shock model. LAME reduced the production of NO and PGE(2) in LPS-activated macrophages. This effect involved the inhibition of NOS-2 and COX-2 gene expression, acting at the transcription level. Examination of the effects of the diterpene on NF-κB signaling showed that LAME inhibits the phosphorylation of IκBα and IκBß, preventing their degradation and the nuclear translocation of the NF-κB p65 subunit. Moreover, inhibition of MAPK signaling was also observed. A further experiment revealed that LAME inhibited the phosphorylation of transforming growth factor-ß (TGF-ß)-activated kinase 1 (TAK1), an upstream signaling molecule required for IKK and mitogen-activated protein kinases (MAPKs) activation. Inflammatory cytokines such as IL-6, TNF-α and IP-10 were downregulated in the presence of this compound after stimulation with LPS. Additionally, LAME also improved survival in a mouse model of endotoxemia and reduced the circulatory levels of cytokines (IL-6, TNF-α). In conclusion, these results indicate that labdane diterpene LAME significantly attenuates the pro-inflammatory response induced by LPS both in vivo and in vitro.

Macrophages, inflammation, and tumor suppressors: ARF, a new player in the game.

The interaction between tumor progression and innate immune system has been well established in the last years. Indeed, several lines of clinical evidence indicate that immune cells such as tumor-associated macrophages (TAMs) interact with tumor cells, favoring growth, angiogenesis, and metastasis of a variety of cancers. In most tumors, TAMs show properties of an alternative polarization phenotype (M2) characterized by the expression of a series of chemokines, cytokines, and proteases that promote immunosuppression, tumor proliferation, and spreading of the cancer cells. Tumor suppressor genes have been traditionally linked to the regulation of cancer progression; however, a growing body of evidence indicates that these genes also play essential roles in the regulation of innate immunity pathways through molecular mechanisms that are still poorly understood. In this paper, we provide an overview of the immunobiology of TAMs as well as what is known about tumor suppressors in the context of immune responses. Recent advances regarding the role of the tumor suppressor ARF as a regulator of inflammation and macrophage polarization are also reviewed.

Dehydroisohispanolone as a Promising NLRP3 Inhibitor Agent: Bioevaluation and Molecular Docking.

Dehydroisohispanolone (DIH), is a labdane diterpene that has exhibited anti-inflammatory activity via inhibition of NF-κB activation, although its potential effects on inflammasome activation remain unexplored. This study aims to elucidate whether DIH modulates NLR family pyrin domain-containing protein 3 (NLRP3) inflammasome in macrophages. Our findings show that DIH inhibited NLRP3 activation triggered by Nigericin (Nig), adenosine triphosphate (ATP) and monosodium urate (MSU) crystals, indicating broad inhibitory effects. DIH significantly attenuated caspase-1 activation and secretion of the interleukin-1ß (IL-1ß) in J774A.1 cells. Interestingly, the protein expressions of NLRP3, apoptosis-associated speck-like protein containing a CARD (ASC), pro-caspase-1 and pro-IL-1ß were not affected by DIH treatment. Furthermore, we found that DIH pretreatment also inhibited the lipopolysaccharide (LPS)-induced NLRP3 inflammasome priming stage. In addition, DIH alleviated pyroptosis mediated by NLRP3 inflammasome activation. Similar results on IL-1ß release were observed in Nig-activated bone marrow-derived macrophages (BMDMs). Covalent molecular docking analysis revealed that DIH fits well into the ATP-binding site of NLRP3 protein, forming a covalent bond with Cys415. In conclusion, our experiments show that DIH is an effective NLRP3 inflammasome inhibitor and provide new evidence for its application in the therapy of inflammation-related diseases.

Synthesis and induction of apoptosis signaling pathway of ent-kaurane derivatives.

Thirty one ent-kaurane derivatives were prepared from kaurenoic acid (1), grandiflorenic acid (16), 15alpha-acetoxy-kaurenoic acid (26) and 16alpha-hydroxy-kaurenoic acid (31). They were tested for their ability to inhibit cell viability in the mouse leukemic macrophagic RAW 264.7 cell line. The most effective compounds were 12, 20, 21, and 23. These were selected for further evaluation in other human cancer cell lines such as Hela, HepG2, and HT-29. Similar effects were obtained although RAW 264.7 cells were more sensitive. In addition, these compounds were significantly less cytotoxic in non-transformed cells. The apoptotic potential of the most active compounds was investigated and they were able to induce apoptosis with compound 12 being the best inducer. The caspase-3, -8 and -9 activities were measured. The results obtained showed that compounds 12, 21, and 23 induce apoptosis via the activation of caspase-8, whereas compound 20 induces apoptosis via caspase-9. Immunoblot analysis of the expression of p53, Bax, Bcl-2, Bcl-xl, and IAPs in RAW 264.7 cells was also carried out. When cells were exposed to 5 microM of the different compounds, expression levels of p53 and Bax increased whereas levels of antiapoptotic proteins such as Bc1-2, Bc1-x1, and IAPs decreased. In conclusion, kaurane derivatives (12, 20, 21, and 23) induce apoptosis via both the mitochondrial and membrane death receptor pathways, involving the Bcl-2 family proteins. Taken together these results provide a role of kaurane derivatives as apoptotic inducers in tumor cells.

Current status of terpenoids as inflammasome inhibitors.

Increasing evidence supports NLRP3 inflammasome as a new target to control inflammation. Dysregulation of NLRP3 inflammasome has been reported to be involved in the pathogenesis of several human inflammatory diseases. However, no NLRP3 inflammasome inhibitors are available in clinic. Terpenoids are natural products with multi-target activities against inflammation. Recent studies have revealed that these compounds are capable of inhibiting the activation of NLRP3 inflammasome in several mouse models of NLRP3 inflammasome-related pathogenesis. Thus, terpenoids represent an interesting pharmacological approach for the treatment of inflammatory diseases as they are endowed with a dual mechanism of inhibition of NF-KB transcription factor and inflammasome activation, both critically involved in their anti-inflammatory effects. This work provides an overview of the current knowledge on the therapeutic potential of terpenoids as NLRP3 inflammasome inhibitors.