Diosgenin, a plant steroid, induces apoptosis in human rheumatoid arthritis synoviocytes with cyclooxygenase-2 overexpression

In the present study, we have shown for the first time that a plant steroid, diosgenin, causes an inhibition of the growth of fibroblast-like synoviocytes from human rheumatoid arthritis, with apoptosis induction associated with cyclooxygenase-2 (COX-2) up-regulation. Celecoxib, a selective COX-2 inhibitor, provoked a large decrease in diosgenin-induced apoptosis even in the presence of exogenous prostaglandin E(2), whereas interleukin-1β, a COX-2 inducer, strongly increased diosgenin-induced apoptosis of these synoviocytes. These findings suggest that the proapoptotic effect of diosgenin is associated with overexpression of COX-2 correlated with overproduction of endogenous prostaglandin E(2). We also observed a loss of mitochondrial membrane potential, caspase-3 activation, and DNA fragmentation after diosgenin treatment

Les cellules leucémiques de LAL modulent-elles l'angiogenèse dans la moelle osseuse ? Rôle de l'endothéline-1 et de l'hypoxie

Increased microvessel density has been described in the bone marrow of patients with Acute Lymphoblastic Leukemia (ALL). The bone marrow is an hypoxic microenvironment, and hypoxia is an important event in triggering angiogenesis. However, the crosstalk between ALL cells and endothelial cells has not been well explored, and usual in vitro assays use cells maintained under 21% O2, which did not mimic bone marrow environment. In this study, the angiogenic activity of factors secreted by the human B-ALL Nalm-6 cell line was tested by using conditioned serum-free medium, that was applied on the human bone marrow endothelial cells HBME-1. Under 21% O2, factors secreted by Nalm-6 cells induced an angiogenic response on HBME-1 cells in vitro. This angiogenic response was not dependent on VEGF secretion but involved, at least in part, the endothelin-endothelin receptor axis. The influence of hypoxia was then studied by culturing both cell lines under 5% O2, an oxygen tension that fits the bone marrow microenvironment. Hypoxia stimulated the secretion of VEGFA by both Nalm-6 and HBME-1 cells, but the angiogenic response to leukemic conditioned medium was altered by chronic hypoxia, which affects the ability of endothelial cells to respond to endothelin-1. Thus, we concluded that leukemic secretion products did not induce angiogenesis at oxygen conditions met in vivo. This work highlights the importance of the oxygen rate in the modulation of cell interactions within the bone marrow, not yet well explored in ALL

Les cellules leucémiques de LAL modulent-elles l'angiogenèse dans la moelle osseuse ? Rôle de l'endothéline-1 et de l'hypoxie

Increased microvessel density has been described in the bone marrow of patients with Acute Lymphoblastic Leukemia (ALL). The bone marrow is an hypoxic microenvironment, and hypoxia is an important event in triggering angiogenesis. However, the crosstalk between ALL cells and endothelial cells has not been well explored, and usual in vitro assays use cells maintained under 21% O2, which did not mimic bone marrow environment. In this study, the angiogenic activity of factors secreted by the human B-ALL Nalm-6 cell line was tested by using conditioned serum-free medium, that was applied on the human bone marrow endothelial cells HBME-1. Under 21% O2, factors secreted by Nalm-6 cells induced an angiogenic response on HBME-1 cells in vitro. This angiogenic response was not dependent on VEGF secretion but involved, at least in part, the endothelin-endothelin receptor axis. The influence of hypoxia was then studied by culturing both cell lines under 5% O2, an oxygen tension that fits the bone marrow microenvironment. Hypoxia stimulated the secretion of VEGFA by both Nalm-6 and HBME-1 cells, but the angiogenic response to leukemic conditioned medium was altered by chronic hypoxia, which affects the ability of endothelial cells to respond to endothelin-1. Thus, we concluded that leukemic secretion products did not induce angiogenesis at oxygen conditions met in vivo. This work highlights the importance of the oxygen rate in the modulation of cell interactions within the bone marrow, not yet well explored in ALL

Efficient new synthesis of N-arylbenzo[b]furo[3,2-d]pyrimidin-4-amines and their benzo[b]thieno[3,2-d]pyrimidin-4-amine analogues via a microwave-assisted Dimroth rearrangement

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Effect of diosgenin on DNA fragmentation after stimulation with IL-1β (an inducer of cyclooxygenase-2 COX-2)

<p><b>Copyright information:</b></p><p>Taken from "Diosgenin, a plant steroid, induces apoptosis in human rheumatoid arthritis synoviocytes with cyclooxygenase-2 overexpression"</p><p>Arthritis Research & Therapy 2004;6(4):R373-R383.</p><p>Published online 17 Jun 2004</p><p>PMCID:PMC464911.</p><p>Copyright © 2004 Liagre et al.; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.</p> Human rheumatoid arthritis fibroblast-like synoviocytes (FLS) were preincubated with or without IL-1β (1 ng/ml) for 4 hours and then 40 μM diosgenin was added for 24 or 48 hours. Measurements were made on FLS from four different patients. Data are expressed as mean ± SD of four experiments. *A value of less than 0.05 (Fisher's protected-least-significant-difference test) was considered to indicate significance in comparison with diosgenin alone. OD, optical density

Microwave-accelerated Dimroth rearrangement for the synthesis of 4-anilino-6-nitroquinazolines. Application to an efficient synthesis of a microtubule destabilizing agent.

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Comparative study on gene expression profile in rat lung after repeated exposure to diesel and biodiesel exhausts upstream and downstream of a particle filter

International audienceBiodiesel is considered as a valuable and less toxic alternative to diesel. However, cellular and molecular effects of repeated exposure to biodiesel emissions from a recent engine equipped with a diesel particle filter (DPF) remain to be characterized. To gain insights about this point, the lung transcriptional signatures were analyzed for rats (n = 6 per group) exposed to filtered air, 30% rapeseed biodiesel (B30) blend or reference diesel (RF0), upstream and downstream a DPF, for 3 weeks (3 h/day, 5 days/week). Genomic analysis revealed a modest regulation of gene expression level (lower than a 2-fold) by both fuels and a higher number of genes regulated downstream the DPF than upstream, in response to either RF0 or to B30 exhaust emissions. The presence of DPF was found to notably impact the lung gene signature of rats exposed to B30. The number of genes regulated in common by both fuels was low, which is likely due to differences in concentrations of regulated pollutants in exhausts, notably for compound organic volatiles, polycyclic aromatic hydrocarbons, NO or NOx. Nevertheless, we have identified some pathways that were activated for both exhaust emissions, such as integrin-, IGF-1- and Rac-signaling pathways, likely reflecting the effects of gas phase products. By contrast, some canonical pathways relative to &quot;oxidative phosphorylation&quot; and &quot;mitochondrial dysfunction&quot; appear as specific to B30 exhaust emission; the repression of transcripts of mitochondrial respiratory chain in lung of rats exposed to B30 downstream of DPF supports the perturbation of mitochondria function. This study done with a recent diesel engine (compliant with the European IV emission standard) and commercially-available fuels reveals that the diesel blend composition and the presence of an after treatment system may modify lung gene signature of rats repeatedly exposed to exhaust emissions, however in a rather modest manner

Effect of diosgenin on DNA fragmentation after incubation with celecoxib (an inhibitor of cyclooxygenase-2 COX-2) or exogenous prostaglandin E(PGE)

<p><b>Copyright information:</b></p><p>Taken from "Diosgenin, a plant steroid, induces apoptosis in human rheumatoid arthritis synoviocytes with cyclooxygenase-2 overexpression"</p><p>Arthritis Research & Therapy 2004;6(4):R373-R383.</p><p>Published online 17 Jun 2004</p><p>PMCID:PMC464911.</p><p>Copyright © 2004 Liagre et al.; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.</p> (a) Human rheumatoid arthritis fibroblast-like synoviocytes (FLS) were preincubated with or without celecoxib (1 μM) for 4 hours and then 40 μM diosgenin was added for 24 or 48 hours. Measurements were made on FLS from four different patients. Data are expressed as mean ± SD of four experiments. *A value of less than 0.05 (Fisher's protected-least-significant-difference test [PLSD]) was considered to indicate significance in comparison with diosgenin alone. (b) Cells were preincubated with or without celecoxib (1 μM) in the absence or presence of PGE(10 nM) for 4 hours, followed by incubation with 40 μM diosgenin for an additional 24 hours. Measurements were made on FLS from four different patients. Data are expressed as mean ± SD of four experiments. *A -value of less than 0.05 (Fisher's PLSD test) was considered to indicate significance in comparison with diosgenin alone. OD, optical density

Analysis of mitochondrial membrane potential (Δψm) after diosgenin treatment

<p><b>Copyright information:</b></p><p>Taken from "Diosgenin, a plant steroid, induces apoptosis in human rheumatoid arthritis synoviocytes with cyclooxygenase-2 overexpression"</p><p>Arthritis Research & Therapy 2004;6(4):R373-R383.</p><p>Published online 17 Jun 2004</p><p>PMCID:PMC464911.</p><p>Copyright © 2004 Liagre et al.; licensee BioMed Central Ltd. This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original URL.</p> Human rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) were cultured in 10% FCS medium for 48 hours and then treated or not with 40 μM diosgenin. Δψm was analyzed in adherent RA FLS after 24 hours of treatment, using the potential-dependent aggregate-forming lipophilic cation JC-1 (5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazole carbocyanide iodide). Red fluorescence (a) represents mitochondria with intact membrane potential whereas green fluorescence (b) represents de-energized mitochondria. Staining with DAPI (4',6-diamidino-2-phenylindole), showed that diosgenin treatment of cells altered the extracellular and nuclear membrane permeability, as is shown by the nuclear localization of the DAPI (b, white arrows) in comparison with untreated cells (a). Pictures were taken with a Nikon microscope ECLIPSE E800 (original magnification ×400). One of three representative experiments from three different patients is shown