Thioredoxin-1 and its mimetic peptide improve systolic cardiac function and remodeling after myocardial infarction.

Myocardial infarction (MI) is characterized by a significant loss of cardiomyocytes (CMs), and it is suggested that reactive oxygen species (ROS) are involved in cell cycle arrest, leading to impaired CM renewal. Thioredoxin-1 (Trx-1) scavenges ROS and may play a role in restoring CM renewal. However, the truncated form of Trx-1, Trx-80, can compromise its efficacy by exerting antagonistic effects. Therefore, a Trx-1 mimetic peptide called CB3 was tested as an alternative way to restore CMs. This study aimed to investigate the effects of Trx-1, Trx-80, and CB3 on mice with experimental MI and study the underlying mechanism of CB3 on CMs. Mouse cardiac parameters were quantified by echocardiography, and infarction size and fibrosis determined using Trichrome and Picro-Sirius Red staining. The study found that Trx-1 and CB3 improved mouse cardiac function, reduced the size of cardiac infarct and fibrosis, and decreased the expression of cardiac inflammatory markers. Furthermore, CB3 polarized macrophages into M2 phenotype, reduced apoptosis and oxidative stress after MI, and increased CM proliferation in cell culture and in vivo. CB3 effectively protected against myocardial infarction and could represent a new class of compounds for treating MI.

Human Plasma Thioredoxin-80 Increases With Age and in ApoE-/- Mice Induces Inflammation, Angiogenesis, and Atherosclerosis.

BACKGROUND: Thioredoxin (TRX)-1, a ubiquitous 12-kDa protein, exerts antioxidant and anti-inflammatory effects. In contrast, the truncated form, called TRX80, produced by macrophages induces upregulation of proinflammatory cytokines. TRX80 also promotes the differentiation of mouse peritoneal and human macrophages toward a proinflammatory M1 phenotype. METHODS: TRX1 and TRX80 plasma levels were determined with a specific ELISA. A disintegrin and metalloproteinase domain-containing protein (ADAM)-10, ADAM-17, and ADAM-10 activities were measured with SensoLyte 520 ADAM10 Activity Assay Kit, Fluorimetric, and InnoZyme TACE Activity Kit, respectively. Western immunoblots were performed with specific antibodies to ADAM-10 or ADAM-17. Angiogenesis study was evaluated in vitro with human microvascular endothelial cells-1 and in vivo with the Matrigel plug angiogenesis assay in mice. The expression of macrophage phenotype markers was investigated with real-time polymerase chain reaction. Phosphorylation of Akt, mechanistic target of rapamycin, and 70S6K was determined with specific antibodies. The effect of TRX80 on NLRP3 inflammasome activity was evaluated by measuring the level of interleukin-1ß and -18 in the supernatants of activated macrophages with ELISA. Hearts were used for lesion surface evaluation and immunohistochemical studies, and whole descending aorta were stained with Oil Red O. For transgenic mice generation, the human scavenger receptor (SR-A) promoter/enhancer was used to drive macrophage-specific expression of human TRX80 in mice. RESULTS: In this study, we observed a significant increase of plasma levels of TRX80 in old subjects compared with healthy young subjects. In parallel, an increase in expression and activity of ADAM-10 and ADAM-17 in old peripheral blood mononuclear cells compared with those of young subjects was observed. Furthermore, TRX80 was found to colocalize with tumor necrosis factor-α, a macrophage M1 marker, in human atherosclerotic plaque. In addition, TRX80 induced the expression of murine M1 macrophage markers through Akt2/mechanistic target of rapamycin-C1/70S6K pathway and activated the inflammasome NLRP3, leading to the release of interleukin-1ß and -18, potent atherogenic cytokines. Moreover, TRX80 exerts a powerful angiogenic effect in both in vitro and in vivo mouse studies. Finally, transgenic mice that overexpress human TRX80 specifically in macrophages of apoE-/- mice have a significant increase of aortic atherosclerotic lesions. CONCLUSIONS: TRX80 showed an age-dependent increase in human plasma. In mouse models, TRX80 was associated with a proinflammatory status and increased atherosclerosis.

Anti-inflammatory and antiatherogenic effects of the NLRP3 inflammasome inhibitor arglabin in ApoE2.Ki mice fed a high-fat diet.

BACKGROUND: This study was designed to evaluate the effect of arglabin on the NLRP3 inflammasome inhibition and atherosclerotic lesion in ApoE2Ki mice fed a high-fat Western-type diet. METHODS AND RESULTS: Arglabin was purified, and its chemical identity was confirmed by mass spectrometry. It inhibited, in a concentration-dependent manner, interleukin (IL)-1ß and IL-18, but not IL-6 and IL-12, production in lipopolysaccharide and cholesterol crystal-activated cultured mouse peritoneal macrophages, with a maximum effect at ≈50 nmol/L and EC50 values for both cytokines of ≈ 10 nmol/L. Lipopolysaccharide and cholesterol crystals did not induce IL-1ß and IL-18 production in Nlrp3(-/-) macrophages. In addition, arglabin activated autophagy as evidenced by the increase in LC3-II protein. Intraperitoneal injection of arglabin (2.5 ng/g body weight twice daily for 13 weeks) into female ApoE2.Ki mice fed a high-fat diet resulted in a decreased IL-1ß plasma level compared with vehicle-treated mice (5.2±1.0 versus 11.7±1.1 pg/mL). Surprisingly, arglabin also reduced plasma levels of total cholesterol and triglycerides to 41% and 42%, respectively. Moreover, arglabin oriented the proinflammatory M1 macrophages into the anti-inflammatory M2 phenotype in spleen and arterial lesions. Finally, arglabin treatment markedly reduced the median lesion areas in the sinus and whole aorta to 54% (P=0.02) and 41% (P=0.02), respectively. CONCLUSIONS: Arglabin reduces inflammation and plasma lipids, increases autophagy, and orients tissue macrophages into an anti-inflammatory phenotype in ApoE2.Ki mice fed a high-fat diet. Consequently, a marked reduction in atherosclerotic lesions was observed. Thus, arglabin may represent a promising new drug to treat inflammation and atherosclerosis.

Inhibition of the Inflammasome NLRP3 by Arglabin Attenuates Inflammation, Protects Pancreatic ß-Cells from Apoptosis, and Prevents Type 2 Diabetes Mellitus Development in ApoE2Ki Mice on a Chronic High-Fat Diet.

Intraperitoneal injection of arglabin (2.5 ng/g of body weight, twice daily, 13 weeks) into female human apolipoprotein E2 gene knock-in (ApoE2Ki) mice fed a high-fat Western-type diet (HFD) reduced plasma levels of glucose and insulin by ∼20.0% ± 3.5% and by 50.0% ± 2.0%, respectively, in comparison with vehicle-treated mice. Immunohistochemical analysis revealed the absence of active caspase-3 in islet sections from ApoE2Ki mice fed a HFD and treated with arglabin. In addition, arglabin reduced interleukin-1ß (IL-1ß) production in a concentration-dependent manner in Langerhans islets isolated from ApoE2Ki mice treated with lipopolysaccharide (LPS) and with cholesterol crystals. This inhibitory effect is specific for the inflammasome NOD-like receptor family, pyrin domain-containing 3 (NLRP3) because IL-1ß production was abolished in Langerhans islets isolated from Nlrp3(-/-) mice. In the insulin-secreting INS-1 cells, arglabin inhibited, in a concentration-dependent manner, the maturation of pro-IL-1ß into biologically active IL-1ß probably through the inhibition of the maturation of procaspase-1 into active capsase-1. Moreover, arglabin reduced the susceptibility of INS-1 cells to apoptosis by increasing Bcl-2 levels. Similarly, autophagy activation by rapamycin decreased apoptosis susceptibility while autophagy inhibition by 3-methyladenin treatment promoted apoptosis. Arglabin further increased the expression of the autophagic markers Bcl2-interacting protein (Beclin-1) and microtubule-associated protein 1 light chain 3 II (LC3-II) in a concentration-dependent manner. Thus, arglabin reduces NLRP3-dependent inflammation as well as apoptosis in pancreatic ß-cells in vivo and in the INS-1 cell line in vitro, whereas it increases autophagy in cultured INS-1 cells, indicating survival-promoting properties of the compound in these cells. Hence, arglabin may represent a new promising compound to treat inflammation and type 2 diabetes mellitus development.

PCSK9 polymorphism in a Tunisian cohort: identification of a new allele, L8, and association of allele L10 with reduced coronary heart disease risk.

The c.61_63dupCTG (L10) allele of rs72555377 polymorphism in PCSK9 has been reported to be associated with low-density lipoprotein-cholesterol (LDL-C) levels and with a decreased risk of coronary artery disease (CAD). We investigated the effect of two known alleles for rs72555377, L10 and L11, on the risk of CAD in a Tunisian cohort (218 patients diagnosed by angiography and 125 control subjects). Two subgroups of patients were defined by their level of stenosis: ≥50% for CAD and <50% for no-CAD. The genotypes were obtained by the size measurement of fluorescent-labeled PCR products. We identified a novel allele for the rs72555377 polymorphism: an in-frame deletion, c.61_63delCTG (L8). The frequency of the L10 allele was significantly higher in the no-CAD subgroup than in the CAD subgroup (0.210 vs 0.114, p = 0.045), and than in the subgroup of CAD patients presenting a stenosis ≥50% in two or three major coronary arteries (0.210 vs 0.125, p = 0.028). Multiple regression analysis showed that the L10 allele was significantly associated with a reduced risk of CAD (p = 0.049, OR = 0.51[0.26-1.00]), and with its reduced severity (p = 0.045, OR = 0.44[0.20-0.98]). The L10 allele is associated with a reduced risk and severity of CAD, seemingly independently of its LDL-lowering effect, suggesting a direct effect of PCSK9 on atherogenesis.

Truncated thioredoxin (Trx-80) promotes pro-inflammatory macrophages of the M1 phenotype and enhances atherosclerosis.

Vascular cells are particularly susceptible to oxidative stress that is believed to play a key role in the pathogenesis of cardiovascular disorders. Thioredoxin-1 (Trx-1) is an oxidative stress-limiting protein with anti-inflammatory and anti-apoptotic properties. In contrast, its truncated form (Trx-80) exerts pro-inflammatory effects. Here we analyzed whether Trx-80 might exert atherogenic effects by promoting macrophage differentiation into the M1 pro-inflammatory phenotype. Trx-80 at 1 µg/ml significantly attenuated the polarization of anti-inflammatory M2 macrophages induced by exposure to either IL-4 at 15 ng/ml or IL-4/IL-13 (10 ng/ml each) in vitro, as evidenced by the expression of the characteristic markers, CD206 and IL-10. By contrast, in LPS-challenged macrophages, Trx-80 significantly potentiated the differentiation into inflammatory M1 macrophages as indicated by the expression of the M1 cytokines, TNF-α and MCP-1. When Trx-80 was administered to hyperlipoproteinemic ApoE2.Ki mice at 30 µg/g body weight (b.w.) challenged either with LPS at 30 µg/30 g (b.w.) or IL-4 at 500 ng/30 g (b.w.), it significantly induced the M1 phenotype but inhibited differentiation of M2 macrophages in thymus and liver. When ApoE2.Ki mice were challenged once weekly with LPS for 5 weeks, they showed severe atherosclerotic lesions enriched with macrophages expressing predominantly M1 over M2 markers. Such effect was potentiated when mice received daily, in addition to LPS, the Trx-80. Moreover, the Trx-80 treatment led to a significantly increased aortic lesion area. The ability of Trx-80 to promote differentiation of macrophages into the classical proinflammatory phenotype may explain its atherogenic effects in cardiovascular diseases.

Thioredoxin-1 promotes anti-inflammatory macrophages of the M2 phenotype and antagonizes atherosclerosis.

OBJECTIVE: Oxidative stress is believed to play a key role in cardiovascular disorders. Thioredoxin (Trx) is an oxidative stress-limiting protein with anti-inflammatory and antiapoptotic properties. Here, we analyzed whether Trx-1 might exert atheroprotective effects by promoting macrophage differentiation into the M2 anti-inflammatory phenotype. METHODS AND RESULTS: Trx-1 at 1 µg/mL induced downregulation of p16(INK4a) and significantly promoted the polarization of anti-inflammatory M2 macrophages in macrophages exposed to interleukin (IL)-4 at 15 ng/mL or IL-4/IL-13 (10 ng/mL each) in vitro, as evidenced by the expression of the CD206 and IL-10 markers. In addition, Trx-1 induced downregulation of nuclear translocation of activator protein-1 and Ref-1, and significantly reduced the lipopolysaccharide-induced differentiation of inflammatory M1 macrophages, as indicated by the decreased expression of the M1 cytokines, tumor necrosis factor-α and monocyte chemoattractant protein-1. Consistently, Trx-1 administered to hyperlipoproteinemic ApoE2.Ki mice at 30 µg/30 g body weight challenged either with lipopolysaccharide at 30 µg/30 g body weight or with IL-4 at 500 ng/30 g body weight significantly induced the M2 phenotype while inhibiting differentiation of macrophages into the M1 phenotype in liver and thymus. ApoE2.Ki mice challenged once weekly with lipopolysaccharide for 5 weeks developed severe atherosclerotic lesions enriched with macrophages expressing predominantly M1 over M2 markers. In contrast, however, daily injections of Trx-1 shifted the phenotype pattern of lesional macrophages in these animals to predominantly M2 over M1, and the aortic lesion area was significantly reduced (from 100%±18% to 62.8%±9.8%; n=8; P<0.01). Consistently, Trx-1 colocalized with M2 but not with M1 macrophage markers in human atherosclerotic vessel specimens. CONCLUSIONS: The ability of Trx-1 to promote differentiation of macrophages into an alternative, anti-inflammatory phenotype may explain its protective effects in cardiovascular diseases. These data provide novel insight into the link between oxidative stress and cardiovascular diseases.

Peroxisome proliferator-activated receptor gamma induces apoptosis and inhibits autophagy of human monocyte-derived macrophages via induction of cathepsin L: potential role in atherosclerosis.

Macrophages play a pivotal role in the pathophysiology of atherosclerosis. These cells express cathepsin L (CatL), a cysteine protease that has been implicated in atherogenesis and the associated arterial remodeling. In addition, macrophages highly express peroxisome proliferator-activated receptor (PPAR) γ, a transcription factor that regulates numerous genes important for lipid and lipoprotein metabolism, for glucose homeostasis, and inflammation. Hence, PPARγ might affect macrophage function in the context of chronic inflammation such as atherogenesis. In the present study, we examined the effect of PPARγ activation on the expression of CatL in human monocyte-derived macrophages (HMDM). Activation of PPARγ by the specific agonist GW929 concentration-dependently increased the levels of CatL mRNA and protein in HMDM. By promoter analysis, we identified a functional PPAR response element-like sequence that positively regulates CatL expression. In addition, we found that PPARγ-induced CatL promotes the degradation of Bcl2 without affecting Bax protein levels. Consistently, degradation of Bcl2 could be prevented by a specific CatL inhibitor, confirming the causative role of CatL. PPARγ-induced CatL was found to decrease autophagy through reduction of beclin 1 and LC3 protein levels. The reduction of these proteins involved in autophagic cell death was antagonized either by the CatL inhibitor or by CatL knockdown. In conclusion, our data show that PPARγ can specifically induce CatL, a proatherogenic protease, in HMDM. In turn, CatL inhibits autophagy and induces apoptosis. Thus, the proatherogenic effect of CatL could be neutralized by apoptosis, a beneficial phenomenon, at least in the early stages of atherosclerosis.

Anti-inflammatory and anticoagulant effects of polyphenol-rich extracts from Thymus atlanticus: An in vitro and in vivo study.

ETHNOPHARMACOLOGICAL EVIDENCE: Thymus atlanticus (TA) is used in traditional medicine in Morocco to treat chronic inflammatory diseases, after local and oral treatment. AIM OF STUDY: This study aimed to investigate the in vitro and in vivo anti-inflammatory and anticoagulant activities of an aqueous extract (AE) and polyphenol fraction (PF) derived from TA. MATERIALS AND METHODS: The effect of AE and PF on monocyte chemoattractant protein-1 (MCP-1) production by naïve and LPS-stimulated peritoneal macrophages isolated from C57Bl/6 mice was assessed by ELISA assay. The effect of chronic administration of the extracts at three different doses by oral rout for 2 weeks on blood coagulation and inflammation induced by carrageenan in Wistar rats was evaluated. In addition, the in vitro anticoagulant effect was tested on blood plasma collected from healthy rats using the activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) tests. The acute toxicity of AE was investigated. Phytochemical analysis was carried out by HPLC. RESULTS: Analysis by HPLC indicated rosmarinic acid as the main phenolic acid in TA extracts. Compared to control macrophages, MCP-1 level was lower in medium supplemented with AE at 50 and 500 µg/mL and PF at 500 µg/mL, but higher in medium with PF at 50 µg/mL. Rosmarinic and chicoric acids, served as controls, significantly decreased MCP-1 production. Chronic oral administration of TA extracts prevented inflammation induced by carrageenan and induced a significant prolongation of blood coagulation time, in a dose dependant manner, in Wistar rats. The results of the in vitro assay showed that the coagulation time was significantly prolonged in plasma incubated with extracts in APTT, PT and TT tests. Lethal dose 50 of AE in mice was 27.90 ± 1.19 g/kg. CONCLUSION: This study indicated TA as an herb with anti-inflammatory and anticoagulant proprieties and supports the traditional use of this plant for the treatment of inflammatory diseases.

Antiinflammatory and antiatherogenic effects of the NF-kappaB inhibitor acetyl-11-keto-beta-boswellic acid in LPS-challenged ApoE-/- mice.

OBJECTIVE: In this article, we studied the effect of acetyl-11-keto-beta-boswellic acid (AKbetaBA), a natural inhibitor of the proinflammatory transcription factor NF-kappaB on the development of atherosclerotic lesions in apolipoprotein E-deficient (apoE-/-) mice. METHODS AND RESULTS: Atherosclerotic lesions were induced by weekly LPS injection in apoE-/- mice. LPS alone increased atherosclerotic lesion size by approximately 100%, and treatment with AKbetaBA significantly reduced it by approximately 50%. Moreover, the activity of NF-kappaB was also reduced in the atherosclerotic plaques of LPS-injected apoE-/- mice treated with AKbetaBA. As a consequence, AKbetaBA treatment led to a significant downregulation of several NF-kappaB-dependent genes such as MCP-1, MCP-3, IL-1alpha, MIP-2, VEGF, and TF. By contrast, AKbetaBA did not affect the plasma concentrations of triglycerides, total cholesterol, antioxidized LDL antibodies, and various subsets of lymphocyte-derived cytokines. Moreover, AKbetaBA potently inhibited the IkappaB kinase (IKK) activity immunoprecipitated from LPS-stimulated mouse macrophages and mononuclear cells leading to decreased phosphorylation of IkappaB alpha and inhibition of p65/NF-kappaB activation. Comparable AKbetaBA-mediated inhibition was also observed in LPS-stimulated human macrophages. CONCLUSIONS: The inhibition of NF-kappaB activity by plant resins from species of the Boswellia family might represent an alternative for classical medicine treatments for chronic inflammatory diseases such as atherosclerosis.

Matrix metalloproteinase-12 gene regulation by a PPAR alpha agonist in human monocyte-derived macrophages.

MMP-12, a macrophage-specific matrix metalloproteinase with large substrate specificity, has been reported to be highly expressed in mice, rabbits and human atherosclerotic lesions. Increased MMP-12 from inflammatory macrophages is associated with several degenerative diseases such as atherosclerosis. In this manuscript, we show that IL-1beta, a proinflammatory cytokine found in atherosclerotic plaques, increases both mRNA and protein levels of MMP-12 in human monocyte-derived macrophages (HMDM). Since peroxisome proliferator-activated receptors (PPARs), such as PPARalpha and PPARgamma, are expressed in macrophages and because PPAR activation exerts an anti-inflammatory effect on vascular cells, we have investigated the effect of PPARalpha and gamma isoforms on MMP-12 regulation in HMDM. Our results show that MMP-12 expression (mRNA and protein) is down regulated in IL-1beta-treated macrophages only in the presence of a specific PPARalpha agonist, GW647, in a dose-dependent manner. In contrast, this inhibitory effect was abolished in IL-1beta-stimulated peritoneal macrophages isolated from PPARalpha(-/-) mice and treated with the PPARalpha agonist, GW647. Moreover, reporter gene transfection experiments using different MMP-12 promoter constructs showed a reduction of the promoter activities by approximately 50% in IL-1beta-stimulated PPARalpha-pre-treated cells. However, MMP-12 promoter analysis did not reveal the presence of a PPRE response element. The IL-1beta effect is known to be mediated through the AP-1 binding site. Mutation of the AP-1 site, located at -81 in the MMP-12 promoter region relative to the transcription start site, followed by transfection analysis, gel shift and ChIP experiments revealed that the inhibitory effect was the consequence of the protein-protein interaction between GW 647-activated PPARalpha and c-Fos or c-Jun transcription factors, leading to inhibition of their binding to the AP-1 motif. These studies suggest that PPARalpha agonists may be used therapeutically, not only for lipid disorders, but also to prevent inflammation and atheromatous plaque rupture, where their ability to inhibit MMP-12 expression in HMDM may be beneficial.

A thioredoxin-mimetic peptide exerts potent anti-inflammatory, antioxidant, and atheroprotective effects in ApoE2.Ki mice fed high fat diet.

Aims: Oxidative stress and inflammation play a pathogenic role in atherosclerosis. Thioredoxin-1 (Trx-1) is an anti-oxidative, anti-inflammatory protein with atheroprotective effects. However, in vivo cleavage of Trx-1 generates a truncated pro-inflammatory protein, Trx-80, which compromises the therapeutic use of Trx-1. Here we analysed whether the thioredoxin-mimetic peptide (TxMP), CB3 might exert anti-oxidative, anti-inflammatory, and atheroprotective effects in ApoE2.Ki mice. Methods and results: We synthesized a small TxMP, Ac-Cys-Pro-Cys-amide, CB3 and characterized its antioxidant and anti-inflammatory effects on cultured peritoneal murine macrophages. CB3 significantly and dose-dependently reduced the level of reactive oxygen species in lipopolysaccharides (LPS)-activated macrophages. In addition, it efficiently lowered LPS-induced inflammatory process through NF-κB inhibition, as evidenced by the reduced secretion of monocyte chemoattractant protein-1, interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α by macrophages. Nevertheless, CB3 did not affect cholesterol accumulation in macrophages. A daily-administered dose of 10 µg/g body weight CB3 to ApoE2.Ki mice on high fat diet did not affect plasma of total cholesterol and triglycerides levels but significantly reduced the plasma levels of pro-inflammatory cytokines (IL-33 and TNF-α) and oxidative markers. In contrast, it significantly induced the plasma levels of anti-inflammatory proteins (adiponectin, IL-10). In addition, CB3 reduced the number of pro-inflammatory M1 macrophages in spleen and decreased the ratio of M1/M2 macrophages in atherosclerotic lesion areas. Finally, CB3 significantly reduced the surface area of aortic lesions. Conclusions: Our results clearly showed that similar to the full length Trx-1, CB3 exerts protective effects, by reducing inflammation and oxidative stress in macrophages and in ApoE2.Ki mice. The atheroprotective effect of CB3 opens promising therapeutic approaches for treatment of atherosclerosis.

Ozonized low density lipoprotein (ozLDL) inhibits NF-kappaB and IRAK-1-associated signaling.

OBJECTIVE: Recent studies have provided strong evidence for the presence of ozone in atherosclerotic lesions. In addition, modification of LDL has been suggested to be involved in atherosclerosis. In the present study we wanted to investigate whether LDL exposed to ozone (ozLDL) is able to modulate the NF-kappaB system, as a paradigm for inflammatory signaling. METHODS AND RESULTS: We showed that activation of NF-kappaB by lipopolysaccharide (LPS), a prototypic inducer of innate immunity, was reversibly inhibited by ozLDL in monocytic THP-1 cells in a dose-dependent manner, whereas tumor necrosis factor (TNF) signaling was not affected. This was not attributable to a direct ozone effect or solely the presence of lipoprotein, and neither required direct contact to LPS nor was accompanied by a change in LPS binding. Comparable inhibitory effects of ozLDL were observed in human monocyte/macrophages and endothelial cells. The presence of ozLDL led to a decrease in LPS-induced IkappaB alpha proteolysis and a reduction of kappaB-dependent transcription/target-gene expression. Furthermore, ozLDL markedly lowered stimulus-induced IkappaB kinase (IKK) activity and phosphorylation/proteolysis of interleukin (IL)-1 receptor-associated kinase-1 (IRAK-1). Finally, cholesterol ozonization products were identified as effective ozLDL inhibitory compounds. CONCLUSIONS: Our study demonstrated that ozLDL inhibited NF-kappaB and IRAK-1-associated signaling which may impair immune function and promote apoptosis.

[Metalloproteinases: therapeutic target in atherosclerosis]. / Les métalloprotéases: cibles thérapeutiques dans l'athérosclérose.

Matrix metalloproteinases are a family of enzymes which collectively can cleave all components of the extracellular matrix. In physiological situations, the expression of matrix metalloproteinases is very low. The increase of their expression leads to several diseases as atherosclerosis, restenosis, rheumatoid arthritis and cancers. In atherosclerosis, metalloproteinases are implicated in the rupture of the atheromatous plaque and contribute to acute vascular accident. Consequently, several studies hypothesized that the inhibition of matrix metalloproteinases activity could reduce the volume of the atheromatous plaque and prevent its destabilisation and therefore could be useful in the treatment of atherosclerosis. However, clinical results have so far been inconclusive because matrix metalloproteinases inhibitors are not very specific. The development of selective inhibitors and gene transfer approaches may better suit the treatment of atherosclerosis.

Plasma metalloproteinase-12 and tissue inhibitor of metalloproteinase-1 levels and presence, severity, and outcome of coronary artery disease.

Several matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) have been implicated in the development and outcome of coronary artery disease (CAD). We investigated whether MMP-12 and TIMP-1 levels were associated with risk, severity, and outcome of CAD. Plasma MMP-12 and TIMP-1 levels are measured in 50 and 44 patients with CAD, respectively, by enzyme-linked immunosorbent assay. Of all patients, 16 were taking statins. Patients who were not on statins were classified into 3 groups according to number of >50% stenotic vessels. Compared with 29 volunteers without CAD, patients without statins (n = 34) had higher MMP-12 concentrations (1.71 vs 1.08 ng/ml, p = 0.021). MMP-12 levels were significantly lower in patients with than in those without statin treatment (0.99 vs 1.71 ng/ml, p = 0.008). There was no association between MMP-12 levels and number of >50% stenotic vessels. MMP-12 concentrations were not associated with outcome of CAD. However, plasma TIMP-1 levels were associated with restenosis independently of number of stenotic vessels and age (p = 0.035) but not with risk or severity of CAD. In conclusion, plasma MMP-12 concentration was associated with the presence of CAD. Statin therapy decreases plasma MMP-12 levels in patients with CAD. Increased TIMP-1 levels may prevent restenosis after angioplasty.

The Oxygen Paradox, the French Paradox, and age-related diseases.

A paradox is a seemingly absurd or impossible concept, proposition, or theory that is often difficult to understand or explain, sometimes apparently self-contradictory, and yet ultimately correct or true. How is it possible, for example, that oxygen "a toxic environmental poison" could be also indispensable for life (Beckman and Ames Physiol Rev 78(2):547-81, 1998; Stadtman and Berlett Chem Res Toxicol 10(5):485-94, 1997)?: the so-called Oxygen Paradox (Davies and Ursini 1995; Davies Biochem Soc Symp 61:1-31, 1995). How can French people apparently disregard the rule that high dietary intakes of cholesterol and saturated fats (e.g., cheese and paté) will result in an early death from cardiovascular diseases (Renaud and de Lorgeril Lancet 339(8808):1523-6, 1992; Catalgol et al. Front Pharmacol 3:141, 2012; Eisenberg et al. Nat Med 22(12):1428-1438, 2016)?: the so-called, French Paradox. Doubtless, the truth is not a duality and epistemological bias probably generates apparently self-contradictory conclusions. Perhaps nowhere in biology are there so many apparently contradictory views, and even experimental results, affecting human physiology and pathology as in the fields of free radicals and oxidative stress, antioxidants, foods and drinks, and dietary recommendations; this is particularly true when issues such as disease-susceptibility or avoidance, "healthspan," "lifespan," and ageing are involved. Consider, for example, the apparently paradoxical observation that treatment with low doses of a substance that is toxic at high concentrations may actually induce transient adaptations that protect against a subsequent exposure to the same (or similar) toxin. This particular paradox is now mechanistically explained as "Adaptive Homeostasis" (Davies Mol Asp Med 49:1-7, 2016; Pomatto et al. 2017a; Lomeli et al. Clin Sci (Lond) 131(21):2573-2599, 2017; Pomatto and Davies 2017); the non-damaging process by which an apparent toxicant can activate biological signal transduction pathways to increase expression of protective genes, by mechanisms that are completely different from those by which the same agent induces toxicity at high concentrations. In this review, we explore the influences and effects of paradoxes such as the Oxygen Paradox and the French Paradox on the etiology, progression, and outcomes of many of the major human age-related diseases, as well as the basic biological phenomenon of ageing itself.

Adipophilin increases triglyceride storage in human macrophages by stimulation of biosynthesis and inhibition of beta-oxidation.

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.

Perilipin, a potential substitute for adipophilin in triglyceride storage in human macrophages.

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 droplet-associated 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. Consequently, perilipin, like adipophilin, might play an important role in the conversion of macrophages into foam cells and contribute to lesion formation. Therefore, inhibition of adipophilin might not be sufficient to prevent lesion formation as previously suggested, and perilipin inhibition might be additionally required.

Matrix metalloproteinases: a potential therapeutic target in atherosclerosis.

Mature human atherosclerotic plaques are frequently characterized by a lipid-rich core covered by a fibrous cap composed of fibrillar collagens, elastin, proteoglycans and smooth muscle cells (SMC). Most sudden deaths due to acute myocardial infarction are caused by rupture of coronary atheroma, leading to a prothrombotic response followed by rapid occlusion of the artery. The accumulation of macrophage-derived foam cells in vulnerable shoulder regions of atherosclerotic plaques correlates with increased local release of matrix-degrading metalloproteinases (MMPs) and weak fibrous cap tissue. These findings suggest a potential role of macrophage-derived MMPs in the weakening and ultimate rupture of plaque structures. Consequently, several studies have focussed on the hypothesis that inhibiting MMP activity would reduce plaque volume and prevent plaque rupture and therefore would be useful in the treatment of atherosclerosis. However, current synthetic MMP inhibitors are not very specific and clinical results have so far been inconclusive. The development of selective inhibitors and focal gene transfer approaches may be better suited for the treatment of atherosclerosis.