Association of the methionine sulfoxide reductase A rs10903323 gene polymorphism with cardiovascular disease in patients with rheumatoid arthritis

Polygenic markers of survival and longevity in the antioxidant genes PON1, PON2, MTHFR, MSRA, SOD1, NQO1, and CAT in a 20-year follow-up study in the population from the Volga-Ural region

BACKGROUND

Genetic background of healthy or pathological styles of aging and human lifespan is determined by joint gene interactions. Lucky combinations of antioxidant gene polymorphisms can result in a highly adaptive phenotype, providing a successful way to interact with external triggers. Our purpose was to identify the polygenic markers of survival and longevity in the antioxidant genes among elderly people with physiological and pathological aging.

METHODS

In a 20-year follow-up study of 2350 individuals aged 18-114 years residing in the Volga-Ural region of Russia, sex-adjusted association analyses of MTHFR rs1801133, MSRA rs10098474, PON1 rs662, PON2 rs7493, SOD1 rs2070424, NQO1 rs1131341 and CAT rs1001179 polymorphic loci with longevity were carried out. Survival analysis was subsequently performed using the established single genes and gene-gene combinations as cofactors.

RESULTS

The PON1 rs662*G allele was defined as the main longevity marker in women (OR = 1.44, p = 3E-04 in the log-additive model; HR = 0.77, p = 1.9E-04 in the Cox-survival model). The polymorphisms in the MTHFR, MSRA, PON2, SOD1, and CAT genes had an additive effect on longevity. A strong protective effect of combined MTHFR rs1801133*C, MSRA rs10098474*T, PON1 rs662*G, and PON2 rs7493*C alleles against mortality was obtained in women (HR = 0.81, p = 5E-03). The PON1 rs662*A allele had a meaningful impact on mortality for both long-lived men with cerebrovascular accidents (HR = 1.76, p = 0.027 for the PON1 rs662*AG genotype) and women with cardiovascular diseases (HR = 1.43, p = 0.002 for PON1 rs662*AA genotype). The MTHFR rs1801133*TT (HR = 1.91, p = 0.036), CAT rs1001179*TT (HR = 2.83, p = 0.031) and SOD1 rs2070424*AG (HR = 1.58, p = 0.018) genotypes were associated with the cancer mortality.

CONCLUSION

In our longitudinal 20-year study, we found the combinations of functional polymorphisms in antioxidant genes involved in longevity and survival in certain clinical phenotypes in the advanced age.

Cardiovascular Manifestations in Rheumatoid Arthritis

Rheumatoid arthritis (RA) is a systemic inflammatory disorder that characteristically affects the joints. RA has extra-articular manifestations that can impact multiple organ systems including the heart, lungs, eyes, skin, and brain. Cardiovascular involvement is a leading cause of mortality in RA. Cardiovascular manifestations of RA include accelerated atherosclerosis, heart failure, pericarditis, myocarditis, endocarditis, rheumatoid nodules, and amyloidosis. Inflammation is an important mediator of endothelial dysfunction and is a key driver of cardiovascular risk and complications in patients with RA. Prompt identification of cardiac pathologies in patients with RA is essential for appropriate management and treatment. Choosing the most appropriate treatment regimen is based on individual patient factors. In this article, we provide a comprehensive review of the epidemiology, pathophysiology, clinical manifestations, diagnosis, and medical management of cardiovascular manifestations of RA. We also discuss the relationship between anti-rheumatic medications, specifically non-steroidal anti-inflammatory drugs, corticosteroids, methotrexate, statins, tumor necrosis factor inhibitors, interleukin-6 inhibitors, Janus kinase inhibitors, and cardiovascular disease.

Association of the methionine sulfoxide reductase A rs10903323 gene polymorphism with functional activity and oxidative modification of alpha-1-antitrypsin in COPD patients

OBJECTIVE

Chronic obstructive pulmonary disease (COPD) is multi-factorial disorder which results from environmental influences and genetic factors. We aimed to investigate whether methionine sulfoxide reductase A (MSRA) rs10903323 gene polymorphism is associated with COPD development and severity in Serbian adult population.

METHODS

The study included 155 patients with COPD and 134 healthy volunteers. Genotyping was determined performing home-made polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The difference between the inhibitory activities of normal and oxidized Alpha-1-Antitrypsin (A1AT) against elastase and trypsin was used for determination of Oxidized Alpha-1-Antitrypsin (OxyA1AT) (expressed as % and g/L). Functional activity of A1AT was presented as a specific inhibitor activity to elastase (SIA-Elastase, kU/g).

RESULTS

Frequencies of the genotypes AA, AG and GG were 80.0%, 20.0%, 0% in COPD patients and 80.5%, 18.5% and 1.5% in the control group, and there was no significant difference in genotype or allele distributions between groups. Serum level of A1AT (g/L) and OxyA1AT was significantly higher in COPD patients than in the control group, but functional activity of A1AT (SIA-Elastase) was significantly lower in COPD patients than in the control group. In COPD group, increased level of OxyA1AT was present in G allele carriers who were smokers relative to G allele carriers who were not smokers. In the smoker group of patients with severe and very severe COPD (GOLD3+4), significant increase in OxyA1AT level was present in G allele carriers compared to AA homozygotes.

CONCLUSION

These findings suggest that MSRA rs10903323 gene polymorphism is probably not a risk for COPD by itself but could represent a COPD modifier, since minor, G allele, is associated with an increased level of oxidized A1AT, indicating impaired ability of MSRA to repair oxidized A1AT in COPD-smokers, and in severe form of COPD.

Genome-Wide Assessment of Shared Genetic Architecture Between Rheumatoid Arthritis and Cardiovascular Diseases

Background Patients with rheumatoid arthritis (RA) have a 2- to 10-fold increased risk of cardiovascular disease (CVD), but the biological mechanisms and existence of causality underlying such associations remain to be investigated. We aimed to investigate the genetic associations and underlying mechanisms between RA and CVD by leveraging large-scale genomic data and genetic cross-trait analytic approaches. Methods and Results Within UK Biobank data, we examined the genetic correlation, shared genetics, and potential causality between RA (Ncases=6754, Ncontrols=452 384) and cardiovascular diseases (CVD, Ncases=44 238, Ncontrols=414 900) using linkage disequilibrium score regression, cross-trait meta-analysis, and Mendelian randomization. We observed significant genetic correlations of RA with myocardial infarction (rg:0.40 [95% CI, 0.24-0.56), angina (rg:0.42 [95% CI, 0.28-0.56]), coronary heart diseases (rg:0.41 [95% CI, 0.27-0.55]), and CVD (rg:0.43 [95% CI, 0.29-0.57]) after correcting for multiple testing (P<0.05/5). When stratified by frequent use of analgesics, we found increased genetic correlation between RA and CVD among participants without aspirin usage (rg:0.54 [95% CI, 0.30-0.78] for angina; Pvalue=6.69×10-6) and among participants with paracetamol usage (rg:0.75 [95% CI, 0.20-1.29] for myocardial infarction; Pvalue=8.90×10-3), whereas others remained similar. Cross-trait meta-analysis identified 9 independent shared loci between RA and CVD, including PTPN22 at chr1p13.2, BCL2L11 at chr2q13, and CCR3 at chr3p21.31 (Psingle trait<1×10-3 and Pmeta<5×10-8), highlighting potential shared pathogenesis including accelerating atherosclerosis, upregulating oxidative stress, and vascular permeability. Finally, Mendelian randomization estimates showed limited evidence of causality between RA and CVD. Conclusions Our results supported shared genetic pathogenesis rather than causality in explaining the observed association between RA and CVD. The identified shared genetic factors provided insights into potential novel therapeutic target for RA-CVD comorbidities.

Methionine sulfoxide reductases and cholesterol transporter STARD3 constitute an efficient system for detoxification of cholesterol hydroperoxides

Methionine sulfoxide reductases (MSRs) are key enzymes in the cellular oxidative defense system. Reactive oxygen species oxidize methionine residues to methionine sulfoxide, and the methionine sulfoxide reductases catalyze their reduction back to methionine. We previously identified the cholesterol transport protein STARD3 as an in vivo binding partner of MSRA (methionine sulfoxide reductase A), an enzyme that reduces methionine-S-sulfoxide back to methionine. We hypothesized that STARD3 would also bind the cytotoxic cholesterol hydroperoxides and that its two methionine residues, Met307 and Met427, could be oxidized, thus detoxifying cholesterol hydroperoxide. We now show that in addition to binding MSRA, STARD3 binds all three MSRB (methionine sulfoxide reductase B), enzymes that reduce methionine-R-sulfoxide back to methionine. Using pure 5, 6, and 7 positional isomers of cholesterol hydroperoxide, we found that both Met307 and Met427 on STARD3 are oxidized by 6α-hydroperoxy-3β-hydroxycholest-4-ene (cholesterol-6α-hydroperoxide) and 7α-hydroperoxy-3β-hydroxycholest-5-ene (cholesterol-7α-hydroperoxide). MSRs reduce the methionine sulfoxide back to methionine, restoring the ability of STARD3 to bind cholesterol. Thus, the cyclic oxidation and reduction of methionine residues in STARD3 provides a catalytically efficient mechanism to detoxify cholesterol hydroperoxide during cholesterol transport, protecting membrane contact sites and the entire cell against the toxicity of cholesterol hydroperoxide.

Methionine sulfoxide and the methionine sulfoxide reductase system as modulators of signal transduction pathways: a review

Methionine oxidation and reduction is a common phenomenon occurring in biological systems under both physiological and oxidative-stress conditions. The levels of methionine sulfoxide (MetO) are dependent on the redox status in the cell or organ, and they are usually elevated under oxidative-stress conditions, aging, inflammation, and oxidative-stress related diseases. MetO modification of proteins may alter their function or cause the accumulation of toxic proteins in the cell/organ. Accordingly, the regulation of the level of MetO is mediated through the ubiquitous and evolutionary conserved methionine sulfoxide reductase (Msr) system and its associated redox molecules. Recent published research has provided new evidence for the involvement of free MetO or protein-bound MetO of specific proteins in several signal transduction pathways that are important for cellular function. In the current review, we will focus on the role of MetO in specific signal transduction pathways of various organisms, with relation to their physiological contexts, and discuss the contribution of the Msr system to the regulation of the observed MetO effect.

Parkin Coordinates Platelet Stress Response in Diabetes Mellitus: A Big Role in a Small Cell

Increased platelet activation and apoptosis are characteristic of diabetic (DM) platelets, where a Parkin-dependent mitophagy serves a major endogenous protective role. We now demonstrate that Parkin is highly expressed in both healthy platelets and diabetic platelets, compared to other mitochondria-enriched tissues such as the heart, muscle, brain, and liver. Abundance of Parkin in a small, short-lived anucleate cell suggest significance in various key processes. Through proteomics we identified 127 Parkin-interacting proteins in DM platelets and compared them to healthy controls. We assessed the 11 highest covered proteins by individual IPs and confirmed seven proteins that interacted with Parkin; VCP/p97, LAMP1, HADHA, FREMT3, PDIA, ILK, and 14-3-3. Upon further STRING analysis using GO and KEGG, interactions were divided into two broad groups: targeting platelet activation through (1) actions on mitochondria and (2) actions on integrin signaling. Parkin plays an important role in mitochondrial protection through mitophagy (VCP/p97), recruiting phagophores, and targeting lysosomes (with LAMP1). Mitochondrial β-oxidation may also be regulated by the Parkin/HADHA interaction. Parkin may regulate platelet aggregation and activation through integrin signaling through interactions with proteins like FREMT3, PDIA, ILK, and 14-3-3. Thus, platelet Parkin may regulate the protection (mitophagy) and stress response (platelet activation) in DM platelets. This study identified new potential therapeutic targets for platelet mitochondrial dysfunction and hyperactivation in diabetes mellitus.

Methionine sulfoxide reductase (Msr) dysfunction in human brain disease

Extensive research has shown that oxidative stress is strongly associated with aging, senescence and several diseases, including neurodegenerative and psychiatric disorders. Oxidative stress is caused by the overproduction of reactive oxygen species (ROS) that can be counteracted by both enzymatic and nonenzymatic antioxidants. One of these antioxidant mechanisms is the widely studied methionine sulfoxide reductase system (Msr). Methionine is one of the most easily oxidized amino acids and Msr can reverse this oxidation and restore protein function, with MsrA and MsrB reducing different stereoisomers. This article focuses on experimental and genetic research performed on Msr and its link to brain diseases. Studies on several model systems as well as genome-wide association studies are compiled to highlight the role of MSRA in schizophrenia, Alzheimer's disease, and Parkinson's disease. Genetic variation of MSRA may also contribute to the risk of psychosis, personality traits, and metabolic factors.

Association of Interleukin-17F 7488A/G and 7383A/G Polymorphisms With Rheumatoid Arthritis: A Meta-Analysis

OBJECTIVES

This meta-analysis aims to summarize and estimate the relationship between rheumatoid arthritis (RA) susceptibility and two polymorphisms of interleukin-17F (IL-17F) 7488A/G and 7383A/G.

MATERIALS AND METHODS

PubMed, Embase and Web of Science were searched up to 01 July 2017. Case-control studies with genotype frequencies data for 7488A/G and 7383A/G were included. The pooled effects were calculated by fixed-effect model or random effects model.

RESULTS

A total of seven publications with 1,409 RA patients and 1,303 controls were included in the present meta-analysis. The results indicated that 7488A/G was significantly associated with increased susceptibility to RA (GA vs. AA: odds ratio [OR]=1.43, 95% confidence interval [CI]: 1.07-1.90, p=0.02; GG vs. AA: OR=3.22, 95% CI: 1.54-6.74, p=0.002; GA+GG vs. AA: OR=1.57, 95% CI: 1.02-2.42, p=0.04; GG vs. GA+AA: OR=3.05, 95% CI: 1.46-6.39, p=0.003). In subgroup analysis, 7488A/G was a strong risk factor in Europeans but not in Americans or Africans. No significant association was found between 7383A/G and RA in overall population or ethnic subgroups by all genetic model comparisons.

CONCLUSION

This meta-analysis provided evidence that IL-17F 7488A/G polymorphism is associated with increased RA susceptibility, while no clear correlation was found between 7383A/G and RA.

Mechanisms of vascular comorbidity in autoimmune diseases

Purpose of review

Persuasive statistics support the clinical observation that because of cardiovascular comorbidities patients with inflammatory joint disease die significantly earlier despite anti-inflammatory therapy.

Recent findings

The reason for this earlier death is multifactorial and involves a combination of a complex genetic background, environmental influences, classical cardiovascular risk factors and the impact of anti-inflammatory therapy. We will describe the importance of several new mechanisms, especially the diverse intercellular communication routes including extracellular vesicles and microRNAs that support the development of cardiovascular comorbidities.

Summary

The aim of this review is to give an updated overview about the known risk factors in the development of cardiovascular comorbidities with the latest insights about their mechanism of action. Furthermore, the impact of newly identified risk factors and significance will be discussed.

Defective protein repair under methionine sulfoxide A deletion drives autophagy and ARE-dependent gene transcription

OBJECTIVE

Reduction of oxidized methionines is emerging as a major protein repair pathway. The lack of methionine sulfoxide reductase A (MsrA) exacerbates cardiovascular disease phenotypes driven by increased oxidative stress. However, the role of MsrA on maintaining cellular homeostasis in the absence of excessive oxidative stress is less well understood.

METHODS AND RESULTS

Constitutive genetic deletion of MsrA increased formation of p62-containing protein aggregates, activated autophagy, and decreased a marker of apoptosis in vascular smooth muscle cells (VSMC). The association of Keap1 with p62 was augmented in MsrA-/- VSMC. Keap1 targets the transcription factor Nrf2, which regulates antioxidant genes, for proteasomal degradation. However, in MsrA-/- VSMC, the association of Nrf2 with Keap1 was diminished. Whereas Nrf2 mRNA levels were not decreased in MsrA-/- VSMC, we detected decreased ubiquitination of Nrf2 and a corresponding increase in total Nrf2 protein in the absence of biochemical markers of oxidative stress. Moreover, nuclear-localized Nrf2 was increased under MsrA deficiency, resulting in upregulation of Nrf2-dependent transcriptional activity. Consequently, transcription, protein levels and enzymatic activity of glutamate-cysteine ligase and glutathione reductase were greatly augmented in MsrA-/- VSMC.

SUMMARY

Our findings demonstrate that reversal of methionine oxidation is required for maintenance of cellular homeostasis in the absence of increased oxidative stress. These data provide the first link between autophagy and activation of Nrf2 in the setting of MsrA deletion.

Myristoylated methionine sulfoxide reductase A is a late endosomal protein

Methionine residues in proteins provide antioxidant defense by reacting with oxidizing species, which oxidize methionine to methionine sulfoxide. Reduction of the sulfoxide back to methionine is catalyzed by methionine sulfoxide reductases, essential for protection against oxidative stress. The nonmyristoylated form of methionine sulfoxide reductase A (MSRA) is present in mitochondria, whereas the myristoylated form has been previously reported to be cytosolic. Despite the importance of MSRA in antioxidant defense, its in vivo binding partners and substrates have not been identified. Starting with a protein array, and followed by immunoprecipitation experiments, colocalization studies, and subcellular fractionation, we identified the late endosomal protein, StAR-related lipid transfer domain-containing 3 (STARD3), as a binding partner of myristoylated MSRA, but not of nonmyristoylated MSRA. STARD3 is known to have both membrane-binding and cytosolic domains that are important in STARD3-mediated transport of cholesterol from the endoplasmic reticulum to the endosome. We found that the STARD3 cytosolic domain localizes MSRA to the late endosome. We propose that the previous conclusion that myristoylated MSRA is strictly a cytosolic protein is artifactual and likely due to vigorous overexpression of MSRA. We conclude that myristoylated MSRA is a late endosomal protein that may play a role in lipid metabolism or may protect endosomal proteins from oxidative damage.

Methionine in Proteins: It's Not Just for Protein Initiation Anymore

Methionine in proteins is often thought to be a generic hydrophobic residue, functionally replaceable with another hydrophobic residue such as valine or leucine. This is not the case, and the reason is that methionine contains sulfur that confers special properties on methionine. The sulfur can be oxidized, converting methionine to methionine sulfoxide, and ubiquitous methionine sulfoxide reductases can reduce the sulfoxide back to methionine. This redox cycle enables methionine residues to provide a catalytically efficient antioxidant defense by reacting with oxidizing species. The cycle also constitutes a reversible post-translational covalent modification analogous to phosphorylation. As with phosphorylation, enzymatically-mediated oxidation and reduction of specific methionine residues functions as a regulatory process in the cell. Methionine residues also form bonds with aromatic residues that contribute significantly to protein stability. Given these important functions, alteration of the methionine-methionine sulfoxide balance in proteins has been correlated with disease processes, including cardiovascular and neurodegenerative diseases. Methionine isn't just for protein initiation.

Protein methionine oxidation augments reperfusion injury in acute ischemic stroke

Reperfusion injury can exacerbate tissue damage in ischemic stroke, but little is known about the mechanisms linking ROS to stroke severity. Here, we tested the hypothesis that protein methionine oxidation potentiates NF-κB activation and contributes to cerebral ischemia/reperfusion injury. We found that overexpression of methionine sulfoxide reductase A (MsrA), an antioxidant enzyme that reverses protein methionine oxidation, attenuated ROS-augmented NF-κB activation in endothelial cells, in part, by protecting against the oxidation of methionine residues in the regulatory domain of calcium/calmodulin-dependent protein kinase II (CaMKII). In a murine model, MsrA deficiency resulted in increased NF-κB activation and neutrophil infiltration, larger infarct volumes, and more severe neurological impairment after transient cerebral ischemia/reperfusion injury. This phenotype was prevented by inhibition of NF-κB or CaMKII. MsrA-deficient mice also exhibited enhanced leukocyte rolling and upregulation of E-selectin, an endothelial NF-κB-dependent adhesion molecule known to contribute to neurovascular inflammation in ischemic stroke. Finally, bone marrow transplantation experiments demonstrated that the neuroprotective effect was mediated by MsrA expressed in nonhematopoietic cells. These findings suggest that protein methionine oxidation in nonmyeloid cells is a key mechanism of postischemic oxidative injury mediated by NF-κB activation, leading to neutrophil recruitment and neurovascular inflammation in acute ischemic stroke.

Understanding the Causes and Implications of Endothelial Metabolic Variation in Cardiovascular Disease through Genome-Scale Metabolic Modeling

High-throughput biochemical profiling has led to a requirement for advanced data interpretation techniques capable of integrating the analysis of gene, protein, and metabolic profiles to shed light on genotype-phenotype relationships. Herein, we consider the current state of knowledge of endothelial cell (EC) metabolism and its connections to cardiovascular disease (CVD) and explore the use of genome-scale metabolic models (GEMs) for integrating metabolic and genomic data. GEMs combine gene expression and metabolic data acting as frameworks for their analysis and, ultimately, afford mechanistic understanding of how genetic variation impacts metabolism. We demonstrate how GEMs can be used to investigate CVD-related genetic variation, drug resistance mechanisms, and novel metabolic pathways in ECs. The application of GEMs in personalized medicine is also highlighted. Particularly, we focus on the potential of GEMs to identify metabolic biomarkers of endothelial dysfunction and to discover methods of stratifying treatments for CVDs based on individual genetic markers. Recent advances in systems biology methodology, and how these methodologies can be applied to understand EC metabolism in both health and disease, are thus highlighted.

Etanercept improves endothelial function via pleiotropic effects in rat adjuvant-induced arthritis

OBJECTIVES

To determine the effect of etanercept on endothelial dysfunction and on traditional cardiovascular (CV) risk factors in the adjuvant-induced arthritis (AIA) rat model.

METHODS

At the first signs of arthritis, etanercept (10 mg/kg/3 days, s.c.) or saline was administered for 3 weeks in AIA rats. Body weights and arthritis scores were monitored daily. Endothelial function was studied in aortic rings relaxed with acetylcholine (Ach) with or without inhibitors of nitric oxide synthase (NOS), cyclo-oxygenase (COX-2), arginase, endothelium-derived hyperpolarizing factor and superoxide anions (O2 (-)°) production. Aortic expression of endothelial nitic oxide synthase (eNOS), Ser1177-phospho-eNOS, COX-2, arginase-2, p22(phox) and p47(phox) was evaluated by western blotting analysis. Blood pressure, heart rate and blood levels of triglycerides, cholesterol and glucose were measured.

RESULTS

Etanercept significantly reduced arthritis score (P < 0.001). It improved Ach-induced relaxation (P < 0.05) as a result of increased NOS activity, decreased COX-2/arginase activities and decreased O2 (-)° production. These functional effects relied on increased eNOS expression and phosphorylation, and decreased COX-2, arginase-2 and p22(phox) expressions. No correlation was found between arthritis score and Ach-induced relaxation. The treatment did not change triglycerides, cholesterol and glucose levels, but significantly increased systolic blood pressure and heart rate (P < 0.05).

CONCLUSION

Our data demonstrated that efficient dosage of etanercept on inflammatory symptoms improved endothelial function in AIA. This beneficial effect on endothelial function is disconnected from its impact on CV risk factors and relates to pleiotropic effects of etanercept on endothelial pathways. These results suggest that etanercept could be a good choice for patients with rheumatoid arthritis at high risk of CV events.

Deletion of Methionine Sulfoxide Reductase A Does Not Affect Atherothrombosis but Promotes Neointimal Hyperplasia and Extracellular Signal-Regulated Kinase 1/2 Signaling

OBJECTIVE

Emerging evidence suggests that methionine oxidation can directly affect protein function and may be linked to cardiovascular disease. The objective of this study was to define the role of the methionine sulfoxide reductase A (MsrA) in models of vascular disease and identify its signaling pathways.

APPROACH AND RESULTS

MsrA was readily identified in all layers of the vascular wall in human and murine arteries. Deletion of the MsrA gene did not affect atherosclerotic lesion area in apolipoprotein E-deficient mice and had no significant effect on susceptibility to experimental thrombosis after photochemical injury. In contrast, the neointimal area after vascular injury caused by complete ligation of the common carotid artery was significantly greater in MsrA-deficient than in control mice. In aortic vascular smooth muscle cells lacking MsrA, cell proliferation was significantly increased because of accelerated G1/S transition. In parallel, cyclin D1 protein and cdk4/cyclin D1 complex formation and activity were increased in MsrA-deficient vascular smooth muscle cell, leading to enhanced retinoblastoma protein phosphorylation and transcription of E2F. Finally, MsrA-deficient vascular smooth muscle cell exhibited greater activation of extracellular signal-regulated kinase 1/2 that was caused by increased activity of the Ras/Raf/mitogen-activated protein kinase signaling pathway.

CONCLUSIONS

Our findings implicate MsrA as a negative regulator of vascular smooth muscle cell proliferation and neointimal hyperplasia after vascular injury through control of the Ras/Raf/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase 1/2 signaling pathway.

PEP-1-MsrA ameliorates inflammation and reduces atherosclerosis in apolipoprotein E deficient mice

BACKGROUND

Methionine sulfoxide reductase A (MsrA) is a potent intracellular oxidoreductase and serves as an essential factor that protects cells against oxidative damage. However, therapeutic use of exogenous MsrA in oxidative stress-induced diseases is limited, because it cannot enter the cells. The aim of this study is to investigate whether MsrA with PEP-1, a cell penetrating peptide, fused to its N-terminus can protect against oxidative stress in macrophages and can attenuate atherosclerosis in apolipoprotein E deficient (apoE(-/-)) mice.

METHODS

MsrA and the fusion protein PEP-1-MsrA were expressed and purified using a pET28a expression system. Transduction of the fusion protein into macrophages was confirmed by Western blot and immunofluorescence staining. Intracellular reactive oxygen species (ROS) and apoptosis levels were measured by flow cytometry. In in vivo study, MsrA or PEP-1-MsrA proteins were intraperitoneally injected into apoE(-/-) mice fed a Western diet for 12 weeks. Plasma lipids levels, inflammatory gene expression, and paraoxonase-1 (PON1) and superoxide dismutase (SOD) activities were assessed. Atherosclerotic lesions were analyzed by Oil Red O staining and immunohistochemistry.

RESULTS

PEP-1-MsrA could penetrate the cells and significantly reduced intracellular ROS levels and apoptosis in H2O2-treated macrophages. It also decreased TNFα and IL-1β mRNA levels and increased the IL-10 mRNA level in lipopolysaccharide-treated macrophages. In in vivo study, PEP-1-MsrA injection significantly increased plasma PON1 and SOD activities and decreased plasma monocyte chemoattractant protein 1 (MCP-1) level compared to the injection of vehicle control or MsrA. In PEP-1-MsrA injected mice, hepatic PON1 levels were increased, while the expression of TNFα and IL-6 mRNA in the liver was suppressed. Although plasma total cholesterol and triglyceride levels did not change, the aortic atherosclerosis in PEP-1-MsrA treated mice was significantly reduced. This was accompanied by a reduction of total and apoptotic macrophages in the lesions.

CONCLUSION

Our study provides evidence that PEP-1-MsrA may be a potential therapeutic agent for atherosclerosis-related cardiovascular diseases.

Hepatic overexpression of methionine sulfoxide reductase A reduces atherosclerosis in apolipoprotein E-deficient mice

Methionine sulfoxide reductase A (MsrA), a specific enzyme that converts methionine-S-sulfoxide to methionine, plays an important role in the regulation of protein function and the maintenance of redox homeostasis. In this study, we examined the impact of hepatic MsrA overexpression on lipid metabolism and atherosclerosis in apoE-deficient (apoE^−/−) mice. In vitro study showed that in HepG2 cells, lentivirus-mediated human MsrA (hMsrA) overexpression upregulated the expression levels of several key lipoprotein-metabolism-related genes such as liver X receptor α, scavenger receptor class B type I, and ABCA1. ApoE^−/− mice were intravenously injected with lentivirus to achieve high-level hMsrA expression predominantly in the liver. We found that hepatic hMsrA expression significantly reduced plasma VLDL/LDL levels, improved plasma superoxide dismutase, and paraoxonase-1 activities, and decreased plasma serum amyloid A level in apoE^−/− mice fed a Western diet, by significantly altering the expression of several genes in the liver involving cholesterol selective uptake, conversion and excretion into bile, TG biosynthesis, and inflammation. Moreover, overexpression of hMsrA resulted in reduced hepatic steatosis and aortic atherosclerosis. These results suggest that hepatic MsrA may be an effective therapeutic target for ameliorating dyslipidemia and reducing atherosclerosis-related cardiovascular diseases.

Regulation of thrombosis and vascular function by protein methionine oxidation

Redox biology is fundamental to both normal cellular homeostasis and pathological states associated with excessive oxidative stress. Reactive oxygen species function not only as signaling molecules but also as redox regulators of protein function. In the vascular system, redox reactions help regulate key physiologic responses such as cell adhesion, vasoconstriction, platelet aggregation, angiogenesis, inflammatory gene expression, and apoptosis. During pathologic states, altered redox balance can cause vascular cell dysfunction and affect the equilibrium between procoagulant and anticoagulant systems, contributing to thrombotic vascular disease. This review focuses on the emerging role of a specific reversible redox reaction, protein methionine oxidation, in vascular disease and thrombosis. A growing number of cardiovascular and hemostatic proteins are recognized to undergo reversible methionine oxidation, in which methionine residues are posttranslationally oxidized to methionine sulfoxide. Protein methionine oxidation can be reversed by the action of stereospecific enzymes known as methionine sulfoxide reductases. Calcium/calmodulin-dependent protein kinase II is a prototypical methionine redox sensor that responds to changes in the intracellular redox state via reversible oxidation of tandem methionine residues in its regulatory domain. Several other proteins with oxidation-sensitive methionine residues, including apolipoprotein A-I, thrombomodulin, and von Willebrand factor, may contribute to vascular disease and thrombosis.

Association between interleukin 17A polymorphisms and susceptibility to rheumatoid arthritis in a Chinese population

BACKGROUND

Previous studies have revealed an association between interleukin 17A (IL17A) polymorphisms and the prevalence of rheumatoid arthritis (RA) in Japanese and Caucasian patients. We hypothesized that IL17A polymorphisms might also affect RA susceptibility in the Chinese population.

METHODS

We studied IL17A rs2275913 G/A, rs3819024 A/G, rs3819025 G/A, rs4711998 A/G, rs8193036 C/T and rs8193037 G/A polymorphisms in 615 RA patients and 839 controls in a Chinese population. Genotyping was performed using a custom-by-design 48-Plex SNP scan™ Kit.

RESULTS

Our results indicated that IL17A rs4711998 A/G and IL17A rs8193037 G/A polymorphisms were not associated with RA, and IL17A rs2275913 G/A and IL17A rs3819024 A/G variant alleles decrease the risk of RA, while IL17A rs3819025 G/A and IL17A rs8193036 C/T variant alleles increase the risk of RA.

CONCLUSIONS

These findings suggest that IL17A polymorphisms may be associated with RA. Future larger studies with other ethnic populations are required to confirm current findings.

Association between polymorphisms of interleukin 10 with inflammatory biomarkers in East Chinese Han patients with rheumatoid arthritis

OBJECTIVES

The aim of the present study was to examine the association between polymorphisms of IL-10 with inflammatory biomarkers in East Chinese Han patients with rheumatoid arthritis (RA).

METHODS

We examined IL-10 rs1800872 A/C polymorphisms in 615 RA patients, and 839 controls, in an East Chinese Han population. Genotyping was performed using a custom-by-design 48-Plex SNP scan TM Kit. The blood plasma concentration of IL-10 was measured using an Iodine [(125)I] IL-10 Radioimmunoassay Kit, in 90 RA patients and 90 controls.

RESULTS

IL-10 rs1800872 A/C polymorphisms were associated with risk of RA. Following stratified analysis, an increased risk of RA was associated with the CC genotype among male, older, C-reactive protein-positive, anti-cyclic citrullinated peptide antibody-positive, and rheumatoid factor-positive-patients, and among patients with a DAS28 of≥3.20 or an erythrocyte sedimentation rate of≥25, and in functional class I and II patients. The average plasma concentration of IL-10 was significantly higher in RA patients compared with controls. RA patients positive for the homozygote CC were characterized by significantly higher levels of IL-10 compared with patients with the heterozygote AC. We also found that there were significant relationships between the single nucleotide polymorphisms in the human IL-10 rs1800872 A/C and production of IL-10.

CONCLUSIONS

Our results suggest that the IL-10 rs1800872 A/C allele might increase the risk of RA. The IL-10 rs1800872 A/C allele might also impact the inflammatory reaction of IL-10 in patients with RA.

Circulating progenitor cells in rheumatoid arthritis: association with inflammation and oxidative stress

OBJECTIVES

To evaluate the association between inflammation, oxidative stress, and circulating progenitor cell (CPC) number and redox equilibrium, vascular lesions and accelerated atherosclerosis in rheumatoid arthritis (RA).

METHOD

Circulating CD34+ cells were isolated from 33 RA patients and 33 controls. Reactive oxygen species (ROS) levels and mRNA expression of manganese superoxide dismutase (MnSOD), catalase (CAT), glutathione peroxidase type 1 (GPx-1) antioxidant enzymes, and the gp91phox-containing nicotinamide adenine dinucleotide phosphate (NADPH) oxidase NOX2 were measured in CD34+ cells. C-reactive protein (CRP), fibrinogen, erythrocyte sedimentation rate (ESR), carotid intima-media thickness (cIMT), and arterial stiffness (AS) were also evaluated. We investigated the relationships between inflammatory markers, vascular parameters, cell number, and antioxidant enzymes.

RESULTS

CD34+ cell number was lower in RA patients than in controls. In CD34+ cells from RA patients, ROS levels, MnSOD mRNA, and NOX2 mRNA were higher, while mRNA expression of GPx-1 and CAT was significantly lower. The AS, pulse wave velocity (PWV), and augmentation index (AIx) were higher, as was cIMT. CD34+ cell number was inversely correlated with CRP, ROS, PWV, and AIx, and with the CAT/MnSOD and GPx-1/MnSOD ratios. CRP was correlated with MnSOD mRNA, PWV, and AIx but not with CAT and GPx-1 mRNA.

CONCLUSIONS

Our data show a link between inflammation, oxidative stress, and the impairment of the antioxidant system of CPCs and their number, and with arterial stiffness in RA subjects. This could suggest a perspective on the accelerated development of vascular damage and atherosclerosis in RA.

Methionine sulfoxide reductase A rs10903323 G/A polymorphism is associated with increased risk of coronary artery disease in a Chinese population

OBJECTIVE

Coronary artery disease (CAD) is a complex disease resulting from a combination of environmental and genetic factors. We hypothesized that polymorphisms in methionine sulfoxide reductase A (MSRA: rs10903323 G/A) and vascular endothelial growth factor A (VEGFA: rs699947 C/A, rs2010963 G/C, and rs3025039 C/T) contribute to CAD susceptibility.

DESIGNS AND METHODS

We examined the association between the four polymorphisms and the risk of CAD in a Chinese population of 435 CAD patients and 480 controls. Genotyping was performed using matrix-assisted laser desorption ionization/time-of-flight mass spectrometry (MALDI/TOF-MS).

RESULTS

When the MSRA rs10903323 GG homozygous genotype was used as the reference group, the GA and GA/AA genotypes were associated with a significantly increased risk of CAD (GA vs GG: adjusted OR=1.36, 95% CI=1.02-1.82, p=0.038; GA/AA vs GG: adjusted OR=1.33, 95% CI=1.01-1.76, p=0.042). The AA homozygous genotype was not associated with a risk of CAD. In the recessive model, when the MSRA rs10903323 GG/GA genotypes were used as the reference group, the AA homozygous genotype was not associated with a risk of CAD. Logistic regression analyses revealed that the VEGFA rs699947 C/A, VEGFA rs2010963 G/C, and VEGFA rs3025039 C/T polymorphisms were not associated with a risk of CAD.

CONCLUSIONS

These findings suggest that the functional MSRA rs10903323 G/A polymorphism is associated with CAD development. However, our results allow only a preliminary conclusion, which must be validated with a larger study of a more diverse ethnic population.

Vascular endothelial growth factor A (VEGFA) polymorphisms in Chinese patients with rheumatoid arthritis

OBJECTIVES

Vascular endothelial growth factor A (VEGFA) is the most potent proangiogenic molecule promoting the angiogenic phenotype of rheumatoid arthritis (RA). We hypothesized that VEGFA polymorphisms may contribute to RA susceptibility.

METHOD

We studied VEGFA rs699947 C/A, rs2010963 G/C, and rs3025039 C/T gene polymorphisms in 329 patients with RA and 697 controls in a Chinese population. Genotyping was performed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS).

RESULTS

VEGFA rs699947 C/A, rs2010963 G/C, and rs3025039 C/T polymorphisms were not associated with the risk of RA. However, in the dominant genetic model, a significantly decreased risk for RA associated with the VEGFA rs699947 CA/AA genotypes was evident among older patients and anti-cyclic citrullinated peptide antibody (ACPA)-negative patients compared with the VEGFA rs699947 CC genotype. A significantly decreased risk for RA associated with the VEGFA rs699947 CA genotype was evident among older patients.

CONCLUSIONS

These findings suggest that the functional single nucleotide polymorphism (SNP) VEGFA rs699947 C/A allele may decrease the risk of RA in older patients and ACPA-negative patients. However, our results were obtained from a moderate-sized sample and therefore this is a preliminary conclusion. Validation by a larger study from a more diverse ethnic population is needed to confirm these findings.

Atherosclerosis and rheumatoid arthritis: more than a simple association

In the last decades a large amount of evidence linked rheumatoid arthritis (RA) to atherosclerosis. In fact, RA patients have an increased risk of cardiovascular events that is not fully explained by other classic cardiovascular risk factors. RA and atherosclerosis may share several common pathomechanisms and inflammation undoubtedly plays a primary role. The proinflammatory cytokines such as tumor necrosis factor alpha and interleukin-6, involved in the pathogenesis of RA, are also independently predictive of subsequent cardiovascular disease (CVD). In RA, inflammation alters HDL constituents and the concentration of LDL and HDL, thus facilitating atherosclerosis and CVD events. On the other hand, also the increase of oxidative processes, frequently observed in RA, induces atherosclerosis. Interestingly, some genetic polymorphisms associated with RA occurrence enhance atherosclerosis, however, other polymorphisms associated with RA susceptibility do not increase CVD risk. Several other mechanisms may influence atherosclerotic processes in RA. Moreover, atherosclerosis may be directly mediated also by underlying autoimmune processes, and indirectly by the occurrence of metabolic syndrome and impaired physical activity. Finally, the effects of RA therapies on cardiovascular system in general and on atherosclerosis in particular are really wide and different. However, the starting point of every RA treatment is that disease control, or better remission, is the best way we have for the reduction of CVD occurrence.