Properties of biomolecular condensates defined by Activator of G-protein Signaling 3.

Activator of G-protein signaling 3 (AGS3; also known as GPSM1), a receptor-independent activator of G-protein signaling, oscillates among defined subcellular compartments and biomolecular condensates (BMCs) in a regulated manner that is likely related to the functional diversity of the protein. We determined the influence of cell stress on the cellular distribution of AGS3 and core material properties of AGS3 BMCs. Cellular stress (oxidative, pHi and thermal) induced the formation of AGS3 BMCs in HeLa and COS-7 cells, as determined by fluorescent microscopy. Oxidative stress-induced AGS3 BMCs were distinct from G3BP1 stress granules and from RNA processing BMCs defined by the P-body protein Dcp1a. Immunoblots indicated that cellular stress shifted AGS3, but not the stress granule protein G3BP1 to a membrane pellet fraction following cell lysis. The stress-induced generation of AGS3 BMCs was reduced by co-expression of the signaling protein Gαi3, but not the AGS3-binding partner DVL2. Fluorescent recovery following photobleaching of individual AGS3 BMCs indicated that there are distinct diffusion kinetics and restricted fluidity for AGS3 BMCs. These data suggest that AGS3 BMCs represent a distinct class of stress granules that serve as a previously unrecognized signal processing node.

Intersection of two key signal integrators in the cell: activator of G-protein signaling 3 and dishevelled-2.

Activator of G-protein signaling 3 (AGS3, encoded by GPSM1) was discovered as a one of several receptor-independent activators of G-protein signaling, which are postulated to provide a platform for divergence between canonical and noncanonical G-protein signaling pathways. Similarly, Dishevelled (DVL) proteins serve as a point of divergence for ß-catenin-dependent and -independent signaling pathways involving the family of Frizzled (FZD) ligands and cell-surface WNT receptors. We recently discovered the apparent regulated localization of dishevelled-2 (DVL2) and AGS3 to distinct cellular puncta, suggesting that the two proteins interact as part of various cell signaling systems. To address this hypothesis, we asked the following questions: (1) do AGS3 signaling pathways influence the activation of ß-catenin (CTNNB1)-regulated transcription through the WNT-Frizzled-Dishevelled axis, and (2) is the AGS3 and DVL2 interaction regulated? The interaction of AGS3 and DVL2 was regulated by protein phosphorylation, subcellular distribution, and a cell-surface G-protein-coupled receptor. These data, and the commonality of functional system impacts observed for AGS3 and DVL2, suggest that the AGS3-DVL2 complex presents an unexpected path for functional integration within the cell.This article has an associated First Person interview with the first author of the paper.

Gαi2 Signaling Regulates Inflammasome Priming and Cytokine Production by Biasing Macrophage Phenotype Determination.

Macrophages exist as innate immune subsets that exhibit phenotypic heterogeneity and functional plasticity. Their phenotypes are dictated by inputs from the tissue microenvironment. G-protein-coupled receptors are essential in transducing signals from the microenvironment, and heterotrimeric Gα signaling links these receptors to downstream effectors. Several Gαi-coupled G-protein-coupled receptors have been implicated in macrophage polarization. In this study, we use genetically modified mice to investigate the role of Gαi2 on inflammasome activity and macrophage polarization. We report that Gαi2 in murine bone marrow-derived macrophages (BMDMs) regulates IL-1ß release after activation of the NLRP3, AIM2, and NLRC4 inflammasomes. We show this regulation stems from the biased polarity of Gαi2 deficient (Gnai2 -/-) and RGS-insensitive Gαi2 (Gnai2 G184S/G184S) BMDMs. We determined that although Gnai2 G184S/G184S BMDMs (excess Gαi2 signaling) have a tendency toward classically activated proinflammatory (M1) phenotype, Gnai2-/- BMDMs (Gαi2 deficient) are biased toward alternatively activated anti-inflammatory (M2) phenotype. Finally, we find that Gαi2-deficient macrophages have increased Akt activation and IFN-ß production but defects in ERK1/2 and STAT3 activation after LPS stimulation. Gαi2-deficient macrophages also exhibit increased STAT6 activation after IL-4 stimulation. In summary, our data indicates that excess Gαi2 signaling promotes an M1 macrophage phenotype, whereas Gαi2 signaling deficiency promotes an M2 phenotype. Understanding Gαi2-mediated effects on macrophage polarization may bring to light insights regarding disease pathogenesis and the reprogramming of macrophages for the development of novel therapeutics.

Role of G-proteins and phosphorylation in the distribution of AGS3 to cell puncta.

Activator of G-protein signaling 3 (AGS3, also known as GPSM1) exhibits broad functional diversity and oscillates among different subcellular compartments in a regulated manner. AGS3 consists of a tetratricopeptide repeat (TPR) domain and a G-protein regulatory (GPR) domain. Here, we tested the hypothesis that phosphorylation of the AGS3 GPR domain regulates its subcellular distribution and functionality. In contrast to the cortical and/or diffuse non-homogeneous distribution of wild-type (WT) AGS3, an AGS3 construct lacking all 24 potential phosphorylation sites in the GPR domain localized to cytosolic puncta. This change in localization was revealed to be dependent upon phosphorylation of a single threonine amino acid (T602). The punctate distribution of AGS3-T602A was rescued by co-expression of Gαi and Gαo but not Gαs or Gαq Following treatment with alkaline phosphatase, both AGS3-T602A and WT AGS3 exhibited a gel shift in SDS-PAGE as compared to untreated WT AGS3, consistent with a loss of protein phosphorylation. The punctate distribution of AGS3-T602A was lost in an AGS3-A602T conversion mutant, but was still present upon T602 mutation to glutamate or aspartate. These results implicate dynamic phosphorylation as a discrete mechanism to regulate the subcellular distribution of AGS3 and associated functionality.

Activator of G-Protein Signaling 3-Induced Lysosomal Biogenesis Limits Macrophage Intracellular Bacterial Infection.

Many intracellular pathogens cause disease by subverting macrophage innate immune defense mechanisms. Intracellular pathogens actively avoid delivery to or directly target lysosomes, the major intracellular degradative organelle. In this article, we demonstrate that activator of G-protein signaling 3 (AGS3), an LPS-inducible protein in macrophages, affects both lysosomal biogenesis and activity. AGS3 binds the Gi family of G proteins via its G-protein regulatory (GoLoco) motif, stabilizing the Gα subunit in its GDP-bound conformation. Elevated AGS3 levels in macrophages limited the activity of the mammalian target of rapamycin pathway, a sensor of cellular nutritional status. This triggered the nuclear translocation of transcription factor EB, a known activator of lysosomal gene transcription. In contrast, AGS3-deficient macrophages had increased mammalian target of rapamycin activity, reduced transcription factor EB activity, and a lower lysosomal mass. High levels of AGS3 in macrophages enhanced their resistance to infection by Burkholderia cenocepacia J2315, Mycobacterium tuberculosis, and methicillin-resistant Staphylococcus aureus, whereas AGS3-deficient macrophages were more susceptible. We conclude that LPS priming increases AGS3 levels, which enhances lysosomal function and increases the capacity of macrophages to eliminate intracellular pathogens.

Regulation of Chemokine Signal Integration by Activator of G-Protein Signaling 4 (AGS4).

Activator of G-protein signaling 4 (AGS4)/G-protein signaling modulator 3 (Gpsm3) contains three G-protein regulatory (GPR) motifs, each of which can bind Gαi-GDP free of Gßγ We previously demonstrated that the AGS4-Gαi interaction is regulated by seven transmembrane-spanning receptors (7-TMR), which may reflect direct coupling of the GPR-Gαi module to the receptor analogous to canonical Gαßγ heterotrimer. We have demonstrated that the AGS4-Gαi complex is regulated by chemokine receptors in an agonist-dependent manner that is receptor-proximal. As an initial approach to investigate the functional role(s) of this regulated interaction in vivo, we analyzed leukocytes, in which AGS4/Gpsm3 is predominantly expressed, from AGS4/Gpsm3-null mice. Loss of AGS4/Gpsm3 resulted in mild but significant neutropenia and leukocytosis. Dendritic cells, T lymphocytes, and neutrophils from AGS4/Gpsm3-null mice also exhibited significant defects in chemoattractant-directed chemotaxis and extracellular signal-regulated kinase activation. An in vivo peritonitis model revealed a dramatic reduction in the ability of AGS4/Gpsm3-null neutrophils to migrate to primary sites of inflammation. Taken together, these data suggest that AGS4/Gpsm3 is required for proper chemokine signal processing in leukocytes and provide further evidence for the importance of the GPR-Gαi module in the regulation of leukocyte function.

Translocation of activator of G-protein signaling 3 to the Golgi apparatus in response to receptor activation and its effect on the trans-Golgi network.

Group II activators of G-protein signaling play diverse functional roles through their interaction with Gαi, Gαt, and Gαo via a G-protein regulatory (GPR) motif that serves as a docking site for Gα-GDP. We recently reported the regulation of the AGS3-Gαi signaling module by a cell surface, seven-transmembrane receptor. Upon receptor activation, AGS3 reversibly dissociates from the cell cortex, suggesting that it may function as a signal transducer with downstream signaling implications, and this question is addressed in the current report. In HEK-293 and COS-7 cells expressing the α2A/D-AR and Gαi3, receptor activation resulted in the translocation of endogenous AGS3 and AGS3-GFP from the cell cortex to a juxtanuclear region, where it co-localized with markers of the Golgi apparatus (GA). The agonist-induced translocation of AGS3 was reversed by the α2-AR antagonist rauwolscine. The TPR domain of AGS3 was required for agonist-induced translocation of AGS3 from the cell cortex to the GA, and the translocation was blocked by pertussis toxin pretreatment or by the phospholipase Cß inhibitor U73122. Agonist-induced translocation of AGS3 to the GA altered the functional organization and protein sorting at the trans-Golgi network. The regulated movement of AGS3 between the cell cortex and the GA offers unexpected mechanisms for modulating protein secretion and/or endosome recycling events at the trans-Golgi network.

Chromosome 9p21 rs10757278 polymorphism is associated with the risk of metabolic syndrome.

Metabolic syndrome (MetS) is a common multifactorial disorder that involves abdominal obesity, dyslipidemia, hypertension, and hyperglycemia. Genome-wide association studies have identified a major risk locus for coronary artery disease and myocardial infarction on chromosome 9p21. Here, we examined the frequency of single nucleotide polymorphisms (SNPs) on chromosome 9p21 in a sample of Turkish patients with MetS and further investigated the correlation between regional SNPs, haplotypes, and MetS. The real-time polymerase chain reaction (RT-PCR) was used to analyze 4 SNPs (rs10757274 A/G, rs2383207 A/G, rs10757278 A/G, rs1333049 C/G) in 291 MetS patients and 247 controls. Analysis of 4 SNPs revealed a significant difference in the genotype distribution for rs2383207, rs10757278, and rs1333049 between MetS patients and controls (p = 0.041, p = 0.005, p = 0.023, respectively) but not for rs10757274 (p = 0.211). MetS and control allelic frequencies for rs2383207, rs10757278, and rs1333049 were statistically different (p < 0.05). The rs2383207 AG variant, was identified as a MetS risk factor (p = 0.012, OR = 33.271; 95 % CI: 2.193-504.805) and the AA haplotype in block 1 and the GC, AG haplotypes in block 2 were associated with MetS (χ(2) = 3.875, p = 0.049; χ(2) = 9.334, p = 0.0022; χ (2) = 9.134, p = 0.0025, respectively). In this study, we found that chromosome 9p21 SNP rs10757278 and related haplotypes correlate with MetS risk. This is the first report showing an association between a 9p21 variant and MetS and suggests that rs10757278 polymorphism may confer increased risk for disease.

Regulation of the AGS3·G{alpha}i signaling complex by a seven-transmembrane span receptor.

G-protein signaling modulators (GPSM) play diverse functional roles through their interaction with G-protein subunits. AGS3 (GPSM1) contains four G-protein regulatory motifs (GPR) that directly bind Gα(i) free of Gßγ providing an unusual scaffold for the "G-switch" and signaling complexes, but the mechanism by which signals track into this scaffold are not well understood. We report the regulation of the AGS3·Gα(i) signaling module by a cell surface, seven-transmembrane receptor. AGS3 and Gα(i1) tagged with Renilla luciferase or yellow fluorescent protein expressed in mammalian cells exhibited saturable, specific bioluminescence resonance energy transfer indicating complex formation in the cell. Activation of α(2)-adrenergic receptors or µ-opioid receptors reduced AGS3-RLuc·Gα(i1)-YFP energy transfer by over 30%. The agonist-mediated effects were inhibited by pertussis toxin and co-expression of RGS4, but were not altered by Gßγ sequestration with the carboxyl terminus of GRK2. Gα(i)-dependent and agonist-sensitive bioluminescence resonance energy transfer was also observed between AGS3 and cell-surface receptors typically coupled to Gα(i) and/or Gα(o) indicating that AGS3 is part of a larger signaling complex. Upon receptor activation, AGS3 reversibly dissociates from this complex at the cell cortex. Receptor coupling to both Gαßγ and GPR-Gα(i) offer additional flexibility for systems to respond and adapt to challenges and orchestrate complex behaviors.

Circulating p53 and cytochrome c levels in acute myocardial infarction patients.

BACKGROUND: Apoptosis causes myocardiocyte loss during and after myocardial infarction. Therapeutic approaches designed to arrest apoptosis would be a significant new development in the recovery of acute myocardial infarction (AMI). In order to examine apoptotic markers in the circulation, serum levels of p53 and cytochrome c were assessed in patients with AMI. METHODS: Blood samples were taken on admission (before initiation of therapy) and on the 3rd and 7th days of hospitalization. Serum levels of p53 and cytochrome c were measured by enzyme-linked immunassay. RESULTS: The serum level of p53 was higher in AMI patients on admission compared to the control group. A time-dependent decrease was observed in the serum level of p53, but there was no significant change in the serum level of cytochrome c during therapy. CONCLUSIONS: p53, but not cytochrome c, appears to have potential as a biomarker for reporting on apoptosis following myocardial infarction.

Effects of serum homocysteine and adiponectin levels on platelet aggregation in untreated patients with essential hypertension.

The aim of the present study is to determine and correlate adiponectin, homocysteine, nitric oxide, and ADP-induced platelet aggregation levels in untreated patients with essential hypertension and healthy individuals. A total of 36 individuals, 23 untreated patients with essential hypertension and 13 healthy individuals, were included in the scope of this study. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum adiponectin and TNF-alpha levels. The levels of serum homocysteine were measured by using competitive chemiluminescent enzyme immunoassay. Serum concentrations of hsCRP were measured by the Nephelometer. Plasma nitrite, nitrate, and total nitric oxide (NOx) levels were determined by colorimetric method. Homocysteine and hsCRP levels in patients with essential hypertension were found to be significantly higher than those in the control group (P = 0.02, P = 0.001, respectively). The average platelet aggregation levels in patient group were higher than control group, but there were no statistically significant differences between them (P > 0.05). In addition, in patients with essential hypertension adiponectin and nitrite levels are significantly lower than control group (P < 0.001, P = 0.045, respectively). We have also found significant correlations between nitrite-platelet aggregation amplitude, nitrite-platelet aggregation slope, nitrite-adiponectin, homocysteine-platelet aggregation amplitude, and sistolic blood pressure-platelet aggregation amplitude levels (r = -0.844; P < 0.001, r = -0.680; P = 0.011, r = 0.454; P = 0.05, r = 0.414; P = 0.05, r = 0.442; P = 0.035, respectively). Increased homocysteine and decreased adiponectin serum levels in patients with essential hypertension correlate well with changes in ADP-induced conventional platelet aggregation. This association may potentially contribute to future thrombus formation and higher risks for cardiovascular events in hypertensive patients.

Serum myeloperoxidase level predicts reperfusion in patients with myocardial infarction receiving thrombolytic therapy.

Polymorphonuclear leukocytes play a central role in all stages of the atherothrombotic inflammatory process. The atherothrombotic activity of polymorphonuclear leukocytes is exerted by mediators such as myeloperoxidase (MPO). Although the role of MPO has been studied with respect to the development of adverse cardiac events in acute coronary syndromes (ACS), the association of this molecule with effectiveness of reperfusion in patients receiving thrombolysis is not yet known. The study population consisted of a total of 158 patients with acute coronary syndromes. Final diagnosis was ST-segment elevation myocardial infarction in 86 patients, 80 of whom received thrombolysis. Blood samples were drawn at presentation of the patients and serum myeloperoxidase levels were measured. Reperfusion was defined in terms of electrocardiographic ST-segment resolution. The serum levels of MPO were found to be correlated with rates of in-hospital adverse events including death (P < 0.001), reinfarction (P < 0.001), recurrent ischemia (P < 0.001), arrhythmias (P < 0.001), clinical heart failure (P < 0.001), and cardiogenic shock (P < 0.001). There was a significant difference in serum MPO levels between subjects with three-vessel disease and two- or one-vessel disease (P < 0.001). Pre-lytic serum high-sensitivity C-reactive protein levels in patients with successful reperfusion were lower than in patients with failed reperfusion (P < 0.001). Analysis of patients with ST segment elevation myocardial infarction receiving thrombolytic therapy revealed that pre-lytic serum MPO levels in patients with successful reperfusion were significantly lower than those of patients with failed reperfusion (P < 0.001). In the present study, serum MPO levels were found to be a strong predictor of response to thrombolytic treatment in patients with ST-segment elevation myocardial infarction. Therefore the level of inflammatory activity in acute coronary syndromes seems to influence the effectiveness of fibrinolysis.

Homocysteine and nitric oxide in patients undergoing diagnostic coronary angiography.

We evaluated the plasma homocysteine (tHcy) and nitric oxide metabolites (nitrite plus nitrate; NOx) data of consecutive patients undergoing diagnostic coronary angiography (n=79) with respect to the presence and severity of coronary artery disease (CAD), the presence of acute coronary syndromes (ACS), and the risk status of patients. Hyperhomocysteinemia (>15 micromol/L) was detected in 11% of the controls (n=19) and 37% of CAD patients (n=60) (p=0.03). Plasma tHcy in CAD patients was not significantly different from controls, but those with 3-vessel disease had a significantly higher tHcy concentrations than did controls (p=0.049). The patients with 3-vessel disease and ACS had the highest concentrations of tHcy (16.9 +- 4.4 micromol/L), and the difference from the ACS patients with 1- and 2-vessel involvement was significant (p=0.03). In patients with 1-vessel involvement, tHcy was correlated with NOx (r=0.62, p=0.005); in patients with 2- and 3-vessel disease this correlation could not be observed. The high-risk patients (n=51) had a higher mean number of vessel involvement and tHcy (p<0.001, p<0.05, respectively) but lower NOx (p<0.05) when compared to the low-risk patients (n=28). It appears that in the early stages of atherosclerosis hyperhomocysteinemia causes an increase in NOx production, but with progression of the disease this compensatory increase disappears.

Tor-dependent post-transcriptional regulation of autophagy: Implications for cancer therapeutics.

Paradoxically, both anticancer immunosurveillance and tumor progression have been associated with intact autophagy, which is regulated by the target of rapamycin (Tor1). Here, we describe the potential impact on the design of cancer therapeutics of a newly described highly conserved post-transcriptional mechanism whereby Tor regulates autophagy.

The relationship between circulating microRNAs and left ventricular mass in symptomatic heart failure patients with systolic dysfunction.

BACKGROUND: In recent years, many microRNAs (miRNAs) were shown to be dysregulated in specific tissues playing critical roles in the pathogenesis and progression of heart failure (HF). Left ventricular (LV) mass (LVM) has long been recognised as an important prognostic marker in systolic HF patients. AIM: We hypothesised that circulating miRNAs may be associated with LVM in systolic HF patients. The present study aimed to evaluate the relationship between previously reported and novel dysregulated circulating miRNAs and echocardiographically determined LVM in symptomatic HF patients with LV systolic dysfunction. METHODS: Forty-two consecutive patients diagnosed with NYHA II-IV symptomatic systolic HF and a control group consisting of 15 age- and sex-matched healthy volunteers were enrolled. After labelling extracted RNA, poly-A tails were added. RNAs were later hybridised on a GeneChip miRNA 2.0 array. After hybridisation and staining, arrays were scanned to determine miRNA expression levels, and differentially expressed miRNAs were identified. RESULTS: Eighteen miRNAs were found to be upregulated in serum of HF patients, while 11 were demonstrated to be downregulated. When the association between dysregulated miRNAs and echocardiographic findings was investigated, miR-182 (p = 0.04), miR-200a* (p = 0.019), and miR-568 (p = 0.023) were found to be inversely correlated with LVM index (LVMI), while miR-155 (p = 0.019) and miR-595 (p = 0.04) were determined to be positively correlated with LVMI. CONCLUSIONS: The results of our study revealed that dysregulated circulating miRNAs were correlated with anatomic changes in LV, in terms of LVMI, in symptomatic HF patients with systolic LV dysfunction.

TOR-dependent post-transcriptional regulation of autophagy.

Regulation of autophagy is required to maintain cellular equilibrium and prevent disease. While extensive study of post-translational mechanisms has yielded important insights into autophagy induction, less is known about post-transcriptional mechanisms that could potentiate homeostatic control. In our study, we showed that the RNA-binding protein, Dhh1 in Saccharomyces cerevisiae and Vad1 in the pathogenic yeast Cryptococcus neoformans is involved in recruitment and degradation of key autophagy mRNAs. In addition, phosphorylation of the decapping protein Dcp2 by the target of rapamycin (TOR), facilitates decapping and degradation of autophagy-related mRNAs, resulting in repression of autophagy under nutrient-replete conditions. The post-transcriptional regulatory process is conserved in both mouse and human cells and plays a role in autophagy-related modulation of the inflammasome product IL1B. These results were then applied to provide mechanistic insight into autoimmunity of a patient with a PIK3CD/p110δ gain-of-function mutation. These results thus identify an important new post-transcriptional mechanism of autophagy regulation that is highly conserved between yeast and mammals.

The role of transcriptional 'futile cycles' in autophagy and microbial pathogenesis.

Eukaryotic cells utilize macroautophagy (hereafter autophagy) to recycle cellular materials during nutrient stress. Target of rapamycin (Tor) is a central regulator of this process, acting by post-translational mechanisms, phosphorylating preformed autophagy-related (Atg) proteins to repress autophagy during log-phase growth. We recently reported an additional role for post-transcriptional regulation of autophagy, whereby the mRNA decapping protein, Dcp2, undergoes Tor-dependent phosphorylation, resulting in increased ATG mRNA decapping and degradation under nutrient-rich, repressing conditions. Dephosphorylation of Dcp2 during starvation is associated with dissociation of the decapping-ATG mRNA complex, with resultant stabilization of, and accumulation of, ATG transcripts, leading to induction of autophagy. Regulation of mRNA degradation occurs in concert with known mRNA synthetic inductive mechanisms to potentiate overall transcriptional regulation. This mRNA degradative pathway thus constitutes a type of transcriptional 'futile cycle' where under nutrient-rich conditions transcript is constantly being generated and degraded. As nutrient levels decline, steady state mRNA levels are increased by both inhibition of degradation as well as increased de novo synthesis. A role for this regulatory process in fungal virulence was further demonstrated by showing that overexpression of the Dcp2-associated mRNA-binding protein Vad1 in the AIDS-associated pathogen Cryptococcus neoformans results in constitutive repression of autophagy even under starvation conditions as well as attenuated virulence in a mouse model. In summary, Tor-dependent post-transcriptional regulation of autophagy plays a key role in the facilitation of microbial pathogenesis.

A conserved mechanism of TOR-dependent RCK-mediated mRNA degradation regulates autophagy.

Autophagy is an essential eukaryotic pathway requiring tight regulation to maintain homeostasis and preclude disease. Using yeast and mammalian cells, we report a conserved mechanism of autophagy regulation by RNA helicase RCK family members in association with the decapping enzyme Dcp2. Under nutrient-replete conditions, Dcp2 undergoes TOR-dependent phosphorylation and associates with RCK members to form a complex with autophagy-related (ATG) mRNA transcripts, leading to decapping, degradation and autophagy suppression. Simultaneous with the induction of ATG mRNA synthesis, starvation reverses the process, facilitating ATG mRNA accumulation and autophagy induction. This conserved post-transcriptional mechanism modulates fungal virulence and the mammalian inflammasome, the latter providing mechanistic insight into autoimmunity reported in a patient with a PIK3CD/p110δ gain-of-function mutation. We propose a dynamic model wherein RCK family members, in conjunction with Dcp2, function in controlling ATG mRNA stability to govern autophagy, which in turn modulates vital cellular processes affecting inflammation and microbial pathogenesis.

Evaluation of association between common genetic variants on chromosome 9p21 and coronary artery disease in Turkish population.

OBJECTIVE: Coronary artery disease (CAD), which develops from complex interactions between genetic and enviromental factors, is a leading cause of death worldwide. Based on genome-wide association studies (GWAS), the chromosomal region 9p21 has been identified as the most relevant locus presenting a strong association with CAD in different populations. The aim of the present study was to investigate the association of two SNPs on chromosome 9p21 on susceptibility to CAD and the effect of these SNPs along with cardiovascular risk factors on the severity of CAD in the Turkish population. METHODS: This study had an observational case-control design. We genotyped 460 subjects, aged 30-65 years, to investigate the association of 2 SNPs (rs1333049, rs2383207) on chromosome 9p21 and CAD risk in Turkish population. Real-time polymerase chain reaction (RT-PCR) was used to analyze the 2 SNPs in CAD patients and healthy controls. The genotype and allelic variations of these SNPs with the severity of CAD was also assessed using semi-quantitative methods such as the Gensini score. Student's t test and multiple regression analysis were used for statistical analysis. RESULTS: The SNPs rs1333049 and rs2383207 were found to be associated with CAD with an adjusted OR of 1.81 (95% Cl 1.05-3.12) and 2.12 (95% CI 1.19-4.10) respectively. After adjustment of CAD risk factors such as smoking, family history of CAD and diabetes, the homozygous AA genotype for rs2383207 increased the CAD risk with an OR 3.69. Also a very strong association was found between rs1333049 and rs2383207 and Gensini scores representing the severity of CAD (p<0.001). CONCLUSION: The rs2383207 and rs1333049 SNPs on 9p21 chromosome were significantly associated with the risk and severity of CAD in the Turkish population.

The prognostic value of circulating microRNAs in heart failure: preliminary results from a genome-wide expression study.

INTRODUCTION: Recent studies have demonstrated the potential of microRNAs (miRNA) as biomarkers in various cardiovascular disorders. The aim of the present study was to quantitatively evaluate the expression levels of miRNAs in patients with chronic congestive heart failure (CHF) in order to identify differential expression profiles as biomarkers with prognostic values. MATERIALS AND METHOD: The study included 20 clinically stable [New York Heart Association (NYHA) II] and 22 decompensated (NYHA III and IV) CHF patients and 15 healthy controls. miRNA profiling was performed using a microarray method. Dysregulated miRNAs were evaluated for their biomarker potential. RESULTS: Microarray profiling revealed an increase in the expression of miR-21, miR-650, miR-744, miR-516-5p, miR-1292, miR-182, miR-1228, miR-595, miR-663b, miR-1296, miR-1825, miR-299-3p, miR-662 miR-122, miR-3148 and miR-518e and a decrease in the expression of miR-129-3p, miR-3155, miR-3175, miR-583, miR-568, miR-30d, miR-200a-star, miR-1979, miR-371-3p, miR-155-star and miR-502-5p in sera of CHF patients. The prognostic value of miR-182 [area under the curve (AUC) 0.695] was found to be superior to pro-brain type natriuretic peptide (NT-proBNP; AUC 0.350) and high-sensitivity C-reactive protein (hs-CRP) (AUC 0.475) by receiver operator characteristic (ROC) analysis. Cox regression analysis showed that miR-182 could predict cardiovascular mortality (P = 0.032). CONCLUSION: We demonstrated the increased expression levels of circulating miRNAs in CHF as compared with controls. Moreover, miR-182 was found to be a potential prognostic marker in CHF.