Papers by Guilhem Larigauderie
Genome Announcements, 2015
We report here the draft genome sequence of Bacillus atrophaeus strain 930029. Strain 930029 show... more We report here the draft genome sequence of Bacillus atrophaeus strain 930029. Strain 930029 shows evidence of drift, based on a comparison to the corresponding source strain publicly available today.
Journal of Microbiological Methods, 2014
Test and evaluation of engineered biothreat agent detection systems ("bi... more Test and evaluation of engineered biothreat agent detection systems ("biodetectors") are a challenging task for government agencies and industries involved in biosecurity and biodefense programs. In addition to user friendly features, biodetectors need to perform both highly sensitive and specific detection, and must not produce excessive false alerts. In fact, the atmosphere displays a number of variables such as airborne bacterial content that can interfere with the detection process, thus impeding comparative tests when carried out at different times or places. To overcome these bacterial air content fluctuations, a standardized reagent bacterial mixture (SRBM), consisting in a collection of selected cultivable environmental species that are prevalent in temperate climate bioaerosols, was designed to generate a stable, reproducible, and easy to use surrogate of bioaerosol sample. The rationale, design, and production process are reported. The results showed that 8.59; CI 95%: 8.46-8.72 log cfu distributed into vials underwent a 0.95; CI 95%: 0.65-1.26 log viability decay after dehydration and subsequent reconstitution, thus advantageously mimicking a natural bioaerosol sample which is typically composed of cultivable and uncultivable particles. Dehydrated SRBM was stable for more than 12months at 4°C and allowed the reconstitution of a dead/live cells aqueous suspension that is stable for 96h at +4°C, according to plate counts. Specific detection of a simulating biothreat agent (e.g. Bacillus atrophaeus) by immuno-magnetic or PCR assays did not display any significant loss of sensitivity, false negative or positive results in the presence of SRBM. This work provides guidance on testing and evaluating detection devices, and may contribute to the establishment of suitable standards and normalized procedures.
Atherosclerosis Supplements, 2005
Atherosclerosis Supplements, 2005
Conclusions. These results show that sPLA2-V is physiologically more relevant for lipopretein met... more Conclusions. These results show that sPLA2-V is physiologically more relevant for lipopretein metabolism and atheresclerosis than sPLA2-IIA.
Atherosclerosis Supplements, 2003
Atherosclerosis Supplements, 2006
Atherosclerosis Supplements, 2006
Objectives: Abnormal lipid deposition in human arteries leads to the formation of fatty streak du... more Objectives: Abnormal lipid deposition in human arteries leads to the formation of fatty streak due to the accumulation of a large number of macrophages derived-foam cells. The formation and catabolism of intracellular lipid droplets is regulated by droplet-associated proteins. Among such proteins, the role of perilipin in human macrophages was unknown.
FEBS Journal, 2006
Lipid accumulation alters macrophage biology and contributes to lipid retention within the vessel... more Lipid accumulation alters macrophage biology and contributes to lipid retention within the vessel wall. In this study, we investigated the role of adipophilin on triglyceride accumulation and lipid-droplet formation in THP-1-derived macrophages (THP-1 macrophages). In the presence of acetylated low-density lipoprotein, macrophages infected with an adenovirus expressing human adipophilin showed a 31% increase in triglyceride content and a greater number of lipid droplets compared with control cells. Incubation of macrophages with very low-density lipoprotein (VLDL) dramatically increased cellular triglyceride content similarly in control and adipophilin-overexpressing cells. By itself, VLDL increased adipophilin expression, which explains the lack of effect of adipophilin overexpression on cellular triglyceride content in macrophages loaded with VLDL. The lipid-droplet content of macrophages was increased by overexpression of adipophilin and/or loading with VLDL. In contrast, inhibition of adipophilin expression using siRNA prevented lipid-droplet formation and significantly reduced intracellular triglyceride content. Using inhibitors of beta-oxidation and acyl-coenzyme A synthetase, results were obtained which suggest that adipophilin elevates cellular lipids by inhibition of beta-oxidation and stimulation of long-chain fatty acid incorporation into triglycerides. Adipophilin expression in THP-1 macrophages altered the cellular content of different lipids and enhanced the size of lipid droplets, consistent with a role for adipophilin in human foam cell formation.
Journal of Vascular Research, 2006
We investigated the effect of plasma levels of human tissue inhibitor of metalloproteinase (hTIMP... more We investigated the effect of plasma levels of human tissue inhibitor of metalloproteinase (hTIMP)-1 on arterial lesion development and aneurysm formation in apolipoprotein-E-deficient mice (ApoE(-/-)). Control and transgenic mice were fed either a chow diet or a high-fat diet for 90 and 180 days. hTIMP-1 has a tendency to decrease atherosclerotic lesions, but did not attain significance (approximately 6% reduction in hTIMP-1(+/+), p = 0.075, and approximately 4% in hTIMP-1(+/0), p = 0.088 vs. control). Immunohistological and histological analyses revealed a reduction in macrophage accumulation (23% of control in hTIMP(+/0), p = 0.065, and 49% of control in hTIMP(+/+), p < 0.05) but not in collagen degradation within the lesion in transgenic mice. Moreover, elastin degradation in sites of pseudo-microaneurysms was reduced in transgenic mice (37% of control in hTIMP-1(+/0), p < 0.05, and 50% of control in hTIMP-1(+/+), p < 0.05). DNA array analysis of matrix metalloproteinase (MMP) expression followed by real-time PCR quantification revealed a significant up-regulation of MMP-3, MMP-12 and MMP-13 in arterial lesions of ApoE(-/-) mice fed a high-fat diet in comparison with the same mice fed a chow diet. These data show that hTIMP-1 reduces aneurysm formation in ApoE(-/-) mice but does not protect them against the development of arterial lesions.
Journal of Molecular Biology, 2003
The infB gene encodes translation initiation factor IF2. We have determined the entire sequence o... more The infB gene encodes translation initiation factor IF2. We have determined the entire sequence of infB from two cold-sensitive Escherichia coli strains IQ489 and IQ490. These two strains have been isolated as suppressor strains for the temperature-sensitive secretion mutation secY24. The mutations causing the suppression phenotype are located within infB. The only variations from the wild-type (wt) infB found in the two mutant strains are a replacement of Asp409 with Glu in strain IQ489 and an insertion of Gly between Ala421 and Gly422 in strain IQ490. Both positions are located in the GTP-binding G-domain of IF2. A model of the G-domain of E.coli IF2 is presented in. Physiological quantities of the recombinant mutant proteins were expressed in vivo in E.coli strains from which the chromosomal infB gene has been inactivated. At 42 degrees C, the mutants sustained normal cell growth, whereas a significant decrease in growth rate was found at 25 degrees C for both mutants as compared to wt IF2 expressed in the control strain. Circular dichroism spectra were recorded of the wt and the two mutant proteins to investigate the structural properties of the proteins. The spectra are characteristic of alpha-helix dominated structure, and reveal a significant different behavior between the wt and mutant IF2s with respect to temperature-induced conformational changes. The temperature-induced conformational change of the wt IF2 is a two-state process. In a ribosome-dependent GTPase assay in vitro the two mutants showed practically no activity at temperatures below 10 degrees C and a reduced activity at all temperatures up to 45 degrees C, as compared to wt IF2. The results indicate that the amino acid residues, Asp409 and Gly422, are located in important regions of the IF2 G-domain and demonstrate the importance of GTP hydrolysis in translation initiation for optimal cell growth.
The Journal of Lipid Research, 2006
Human data raised the possibility that coronary heart disease is associated with mutations in the... more Human data raised the possibility that coronary heart disease is associated with mutations in the apolipoprotein gene cluster APOA1/C3/A4 that result in multideficiency of cluster-encoded apolipoproteins and hypoalphalipoproteinemia. To test this hypothesis, we generated a mouse model for human apolipoprotein A-I (apoA-I)/C-III/A-IV deficiency. Homozygous mutants (Apoa1/c3/a4 2/2 ) lacking the three cluster-encoded apolipoproteins were viable and fertile. In addition, feeding behavior and growth were apparently normal. Total cholesterol (TC), high density lipoprotein cholesterol (HDLc), and triglyceride levels in the plasma of fasted mutants fed a regular chow were 32% (P , 0.001), 17% (P , 0.001), and 70% (P , 0.01), respectively, those of wild-type mice. When fed a high-fat Western-type (HFW) diet, Apoa1/ c3/a4 2/2 mice showed a further decrease in HDLc concentration and a moderate increase in TC, essentially in non-HDL fraction. The capacity of Apoa1/c3/a4 2/2 plasma to promote cholesterol efflux in vitro was decreased to 75% (P , 0.001), and LCAT activity was decreased by 38% (P , 0.01). Despite the very low total plasma cholesterol, the imbalance in lipoprotein distribution caused small but detectable aortic lesions in one-third of Apoa1/c3/a4 2/2 mice fed a HFW diet. In contrast, none of the wild-type mice had lesions. These results demonstrate that Apoa1/c3/a4 2/2 mice display clinical features similar to human apoA-I/C-III/A-IV deficiency (i.e., marked hypoalphalipoproteinemia) and provide further support for the apoa1/c3/a4 gene cluster as a minor susceptibility locus for atherosclerosis in mice.-Mezdour, H., G. Larigauderie, G. Castro, G. Torpier, J. Fruchart, M. Nowak, J-C. Fruchart, M. Rouis, and N. Maeda. Characterization of a new mouse model for human apolipoprotein A-I/C-III/A-IV deficiency. J. Lipid Res. 2006. 47: 912-920.
Journal of Cellular Physiology, 2008
The fate and phenotype of lesion macrophages is regulated by cellular oxidative stress. Thioredox... more The fate and phenotype of lesion macrophages is regulated by cellular oxidative stress. Thioredoxin-1 (Trx-1) plays a major role in the regulation of cellular redox balance, with resultant effects on gene expression and cellular responses including cell growth and death. Trx-1 activity is inhibited by interaction with vitamin D-upregulated protein-1 (VDUP-1). Peroxisome proliferator-activated receptor gamma (PPARg) is expressed by human monocyte-derived macrophages (HMDM) and PPARg agonism has been reported to decrease expression of inflammatory genes and to promote apoptosis of these cells. To determine whether VDUP-1 may be involved in regulating the effects of PPARg agonists in macrophages, we investigated the effect of a synthetic PPARg agonist (GW929) on the expression of VDUP-1 in HMDM. GW929 concentration-dependently increased HMDM expression of VDUP-1 (mRNA and protein). Transfection of different fragments of the VDUP-1 promoter as well as gel shift analysis revealed the presence of functional PPARg response elements (PPRE) in the promoter. Under conditions in which PPAR agonism altered levels of VDUP-1, caspase-3 activity, and macrophage apoptosis were also elevated. The results suggest that PPARg activation stimulates apoptosis in human macrophages by altering the cellular redox balance via regulation of VDUP-1.
Journal of Biological Chemistry, 2005
Oxidative stress plays an important role in atherosclerotic vascular disease, and several recent ... more Oxidative stress plays an important role in atherosclerotic vascular disease, and several recent studies were focused on thioredoxin-1 (Trx-1) and its potential protective role against oxidative stress. Since human monocyte-derived macrophages (HMDM) are important cells in several inflammatory diseases including atherosclerosis, we conducted this study to evaluate the impact of extracellular recombinant human Trx-1 (rhTrx-1) on gene expression in lipopolysaccharide-activated HMDM. Our results showed that rhTrx-1 was capable of reducing interleukin (IL)-1beta mRNA and protein synthesis in a dose-dependent manner. This effect was partly mediated through a reduction of NF-kappaB activation as analyzed by transient transfection and gel shift assays. In addition, we showed that the attenuation of NF-kappaB activity was the result of the reduction of both p50 and p65 subunit mRNA and protein synthesis on one hand and of the induction of I-kappaBalpha mRNA and protein expression on the other hand. Moreover, inhibition of endogenous Trx-1 mRNA was also observed, suggesting a contribution to the diminution of NF-kappaB activity since endogenous Trx-1, in contrast to the exogenous Trx-1, activates the NF-kappaB system. Finally, H2O2-oxidized rhTrx-1 reduced IL-1beta mRNA synthesis in lipopolysaccharide-activated HMDM. This result highly suggested that the rhTrx-1 used in this study could be oxidized in the culture medium and, in turn, reduced IL-1beta mRNA and protein synthesis. Taken together, these data indicated a potential new mechanism through which extracellular rhTrx-1 exerts an anti-inflammatory function in HMDM.
Free Radical Biology and Medicine, 2004
Uptake of modified low-density lipoproteins (LDLs) by macrophages in the arterial wall is an impo... more Uptake of modified low-density lipoproteins (LDLs) by macrophages in the arterial wall is an important event in atherogenesis. Indeed, oxidatively modified LDLs (oxLDLs) are known to affect various cellular processes by modulating oxidation-sensitive signaling pathways. Here we found that the ubiquitous 55 kDa selenoprotein thioredoxin reductase 1 (TrxR1), which is a key enzyme for cellular redox control and antioxidant defense, was upregulated in human atherosclerotic plaques and expressed in foam cells. Using reverse transcription polymerase chain reaction analysis, we also found that oxLDLs, but not native LDLs (nLDLs), dose-dependently increased TrxR1 mRNA in human monocytederived macrophages (HMDMs). This stimulating effect was specific for oxLDLs, as pro-inflammatory factors, such as lipopolysaccharides (LPSs), interleukin-1h (IL-1h), interleukin-6 (Il-6), and tumor necrosis factor a (TNFa), under the same conditions, failed to induce TrxR1 mRNA levels to the same extent. Moreover, phorbol ester-differentiated THP-1 cells or HMDMs transiently transfected with TrxR1 promoter fragments linked to a luciferase reporter gene allowed identification of a defined promoter region as specifically responding to the phospholipid component of oxLDLs (p < .05 vs. phospholipid component of nLDLs). Gel mobility shift analyses identified a short 40-nucleotide stretch of the promoter carrying AP-1 and HoxA5 consensus motifs that responded with an altered shift pattern in THP-1 cells treated with oxLDLs, however, without evident involvement of either the Fos, Jun, Nrf2, or HoxA5 transcription factors. D
Atherosclerosis, 2004
Larigauderie 45 ABCG5 and ABCG8, have been proposed to contribute to the decrease in cholesterol ... more Larigauderie 45 ABCG5 and ABCG8, have been proposed to contribute to the decrease in cholesterol absorption after phytosterols consumption. In the last yem's other biological properties have been ascribed to these plant compounds, such as a dfl'ect immune modulatory activity and a role in cancer protection. Objectives: To explore the moleculm" basis of the effect of phytosterols.
Atherosclerosis, 2006
Abnormal lipid deposition in human arteries leads to the formation of fatty streaks due to the ac... more Abnormal lipid deposition in human arteries leads to the formation of fatty streaks due to the accumulation of a large number of macrophage derived-foam cells. The formation and catabolism of intracellular lipid droplets is regulated by droplet-associated proteins. Among such proteins, the role of perilipin in human macrophages was unknown. In this study, we first showed that perilipin expression was increased during differentiation of human monocytes to macrophages. Interestingly, cellular perilipin content was unaffected by treatment of cells with OxLDL, AcLDL, VLDL or sterol esters. Moreover, its expression was not dependent on the presence of adipophilin, another lipid dropletassociated protein, since it was not affected by transfection of macrophages with siRNA-adipophilin. Perilipin overexpression in macrophages with an expression vector resulted in significant lipid droplet formation and TG accumulation and this was unaffected by decreasing adipophilin levels using siRNA.
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Papers by Guilhem Larigauderie