CTSA Consortium Consensus Scientific Review Committee (SRC) Working Group Report on the SRC Processes

Human research projects must have a scientifically valid study design, analytic plan, and be operationally feasible in order to be successfully completed and thus to have translational impact. To ensure this, institutions that conduct clinical research should have a scientific review process prior to submission to the Institutional Review Committee (IRB). This paper reports the Clinical and Translational Science Award (CTSA) Consortium Scientific Review Committee (SRC) Consensus Working Group's proposed framework for a SRC process. Recommendations are provided for institutional support and roles of CTSAs, multisite research, criteria for selection of protocols that should be reviewed, roles of committee members, application process, and committee process. Additionally, to support the SCR process effectively, and to ensure efficiency, the Working Group recommends information technology infrastructures and evaluation metrics to determine outcomes are provided.

The pathology and pathobiology of bicuspid aortic valve: State of the art and novel research perspectives

Bicuspid aortic valve is the most prevalent cardiac valvular malformation. It is associated with a high rate of long‐term morbidity including development of calcific aortic valve disease, aortic regurgitation and concomitant thoracic aortic aneurysm and dissection. Recently, basic and translational studies have identified some key processes involved in the development of bicuspid aortic valve and its morbidity. The development of aortic valve disease and thoracic aortic aneurysm and dissection is the result of complex interactions between genotypes, environmental risk factors and specific haemodynamic conditions created by bicuspid aortic valve anatomy. Herein, we review the pathobiology of bicuspid aortic valve with a special emphasis on translational aspects of these basic findings. Important but unresolved problems in the pathology of bicuspid aortic valve and thoracic aortic aneurysm and dissection are discussed, along with the molecular processes involved.

Genetic modifiers of response to glucose-insulin-potassium (GIK) infusion in acute coronary syndromes and associations with clinical outcomes in the IMMEDIATE trial

Modifiers of response to glucose, insulin and potassium (GIK) infusion may affect clinical outcomes in acute coronary syndromes (ACS). In an Immediate Myocardial Metabolic Enhancement During Initial Assessment And Treatment In Emergency Care (IMMEDIATE) trial's sub-study (n = 318), we explored effects of 132,634 genetic variants on plasma glucose and potassium response to 12-h GIK infusion. Associations between metabolite-associated variants and infarct size (n = 84) were assessed. The 'G' allele of rs12641551, near ACSL1, as well as the 'A' allele of XPO4 rs2585897 were associated with a differential glucose response (P for 2 degrees of freedom test, P2df ⩽ 4.75 × 10(-7)) and infarct size with GIK (P2df < 0.05). Variants within or near TAS1R3, LCA5, DNAH5, PTPRG, MAGI1, PTCSC3, STRADA, AKAP12, ARFGEF2, ADCYAP1, SETX, NDRG4 and ABCB11 modified glucose response, and near CSF1/AHCYL1 potassium response (P2df ⩽ 4.26 × 10(-7)), but not outcomes. Gene variants may modify glucose and potassium response to GIK infusion, contributing to cardiovascular outcomes in ACS.

A common variant in the CLDN7/ELP5 locus predicts adiponectin change with lifestyle intervention and improved fitness in obese individuals with diabetes

Overweight/obese individuals with Type 2 diabetes have low adiponectin levels, which may improve with lifestyle changes. We investigated whether genetic variants associated with adiponectin levels in genome-wide association studies (GWAS) would also be related with adiponectin changes in response to an intensive lifestyle intervention (ILI), potentially through mechanisms altering the adipose microenvironment via weight loss and/or improved cardiorespiratory fitness. Look AHEAD was a randomized trial comparing the cardiovascular benefits of ILI-induced weight loss and physical activity compared with diabetes support and education among overweight/obese individuals with Type 2 diabetes. In a subsample of Look AHEAD with adiponectin data and genetic consent (n=1,351), we evaluated the effects of 24 genetic variants, demonstrated by GWAS to be cross-sectionally associated with adiponectin, on adiponectin change 1-yr postintervention. We explored via mediational analyses whether any differential effects by treatment arm were occurring through weight loss and/or improved fitness. A variant, rs222857, in the CLDN7 locus, potentially associated with epithelial barrier integrity and tight junction physiology, and a putative cis expression quantitative trail locus for elongator acetyltransferase complex subunit 5 (ELP5), predicted adiponectin increases within ILI (log-adiponectin in overall sample per copy: β±SE=0.05±0.02, P=0.008; in non-Hispanic whites: 0.06±0.02, P=0.009). The favorable effects of rs222857 (minor allele frequency 45.5%) appeared to be mediated by mechanisms associated with improved fitness, and not weight loss. This is the first study to identify a genetic variant that modifies adiponectin response to lifestyle intervention in overweight/obese diabetic individuals.

Calcific aortic valve disease: a consensus summary from the Alliance of Investigators on Calcific Aortic Valve Disease

Calcific aortic valve disease (CAVD) is increasingly prevalent worldwide with significant morbidity and mortality. Therapeutic options beyond surgical valve replacement are currently limited. In 2011, the National Heart Lung and Blood Institute assembled a working group on aortic stenosis. This group identified CAVD as an actively regulated disease process in need of further study. As a result, the Alliance of Investigators on CAVD was formed to coordinate and promote CAVD research, with the goals of identifying individuals at risk, developing new therapeutic approaches, and improving diagnostic methods. The group is composed of cardiologists, geneticists, imaging specialists, and basic science researchers. This report reviews the current status of CAVD research and treatment strategies with identification of areas in need of additional investigation for optimal management of this patient population.

Abstract 77: Distinct Profiles of Transient Receptor Potential Canonical (TRPC) Channel Expression in Biventricular Failure

Heart failure is a major cause of morbidity and mortality. The transient receptor potential canonical (TRPC) family of channels mediate pathologic cardiac remodeling. In particular, TRPC6 participates in a self-propagating circuit that amplifies cardiac hypertrophy and fibrosis. The objective of this study was to explore biventricular expression of TRPCs in advanced heart failure.

Methods: Viable left (LV) and right (RV) ventricular free wall tissue was obtained from human subjects with end-stage heart failure (n=12) referred for transplantation or biventricular assist devices. Control LV and RV tissue was obtained from the National Disease Research Interchange (n=3/group). To explore TRPC expression in a murine model, adult male C57BL/6 mice underwent thoracic aortic constriction (TAC) for 10 weeks (n=6/group). Biventricular tissue was analyzed by real-time polymerase chain reaction.

Results: Compared to normal LV and RV, levels of TRPC 1, 3, 4 and 6 were increased in failing LV and RV samples, respectively. Levels of TRPC1 and TRPC6 were greater in failing RV than failing LV samples. TRPC 5 and 7 expression were not consistently detected in normal or failing tissue samples. Compared to sham LV, levels of TPRC 1, 4 and 6 increased in the LV after TAC. Compared to sham RV, levels of TRPC 3, 4, and 6 increased in the RV after TAC. Levels of TRPC3 were greater in the RV than LV after TAC.

Conclusions: Our results identify distinct profiles of TRPC expression in the RV versus LV in both human tissue and in a murine model of advanced biventricular failure. Levels of select TRPCs are higher in the failing RV compared to LV, suggesting a potentially important role for TRPCs in RV remodeling.

Gene-centric meta-analyses for central adiposity traits in up to 57 412 individuals of European descent confirm known loci and reveal several novel associations

Waist circumference (WC) and waist-to-hip ratio (WHR) are surrogate measures of central adiposity that are associated with adverse cardiovascular events, type 2 diabetes and cancer independent of body mass index (BMI). WC and WHR are highly heritable with multiple susceptibility loci identified to date. We assessed the association between SNPs and BMI-adjusted WC and WHR and unadjusted WC in up to 57 412 individuals of European descent from 22 cohorts collaborating with the NHLBI's Candidate Gene Association Resource (CARe) project. The study population consisted of women and men aged 20-80 years. Study participants were genotyped using the ITMAT/Broad/CARE array, which includes ∼50 000 cosmopolitan tagged SNPs across ∼2100 cardiovascular-related genes. Each trait was modeled as a function of age, study site and principal components to control for population stratification, and we conducted a fixed-effects meta-analysis. No new loci for WC were observed. For WHR analyses, three novel loci were significantly associated (P < 2.4 × 10(-6)). Previously unreported rs2811337-G near TMCC1 was associated with increased WHR (β ± SE, 0.048 ± 0.008, P = 7.7 × 10(-9)) as was rs7302703-G in HOXC10 (β = 0.044 ± 0.008, P = 2.9 × 10(-7)) and rs936108-C in PEMT (β = 0.035 ± 0.007, P = 1.9 × 10(-6)). Sex-stratified analyses revealed two additional novel signals among females only, rs12076073-A in SHC1 (β = 0.10 ± 0.02, P = 1.9 × 10(-6)) and rs1037575-A in ATBDB4 (β = 0.046 ± 0.01, P = 2.2 × 10(-6)), supporting an already established sexual dimorphism of central adiposity-related genetic variants. Functional analysis using ENCODE and eQTL databases revealed that several of these loci are in regulatory regions or regions with differential expression in adipose tissue.

Low-dose dopamine or low-dose nesiritide in acute heart failure with renal dysfunction: the ROSE acute heart failure randomized trial

IMPORTANCE

Small studies suggest that low-dose dopamine or low-dose nesiritide may enhance decongestion and preserve renal function in patients with acute heart failure and renal dysfunction; however, neither strategy has been rigorously tested.

OBJECTIVE

To test the 2 independent hypotheses that, compared with placebo, addition of low-dose dopamine (2 μg/kg/min) or low-dose nesiritide (0.005 μg/kg/min without bolus) to diuretic therapy will enhance decongestion and preserve renal function in patients with acute heart failure and renal dysfunction.

DESIGN, SETTING, AND PARTICIPANTS

Multicenter, double-blind, placebo-controlled clinical trial (Renal Optimization Strategies Evaluation [ROSE]) of 360 hospitalized patients with acute heart failure and renal dysfunction (estimated glomerular filtration rate of 15-60 mL/min/1.73 m2), randomized within 24 hours of admission. Enrollment occurred from September 2010 to March 2013 across 26 sites in North America.

INTERVENTIONS

Participants were randomized in an open, 1:1 allocation ratio to the dopamine or nesiritide strategy. Within each strategy, participants were randomized in a double-blind, 2:1 ratio to active treatment or placebo. The dopamine (n = 122) and nesiritide (n = 119) groups were independently compared with the pooled placebo group (n = 119).

MAIN OUTCOMES AND MEASURES

Coprimary end points included 72-hour cumulative urine volume (decongestion end point) and the change in serum cystatin C from enrollment to 72 hours (renal function end point).

RESULTS

Compared with placebo, low-dose dopamine had no significant effect on 72-hour cumulative urine volume (dopamine, 8524 mL; 95% CI, 7917-9131 vs placebo, 8296 mL; 95% CI, 7762-8830 ; difference, 229 mL; 95% CI, -714 to 1171 mL; P = .59) or on the change in cystatin C level (dopamine, 0.12 mg/L; 95% CI, 0.06-0.18 vs placebo, 0.11 mg/L; 95% CI, 0.06-0.16; difference, 0.01; 95% CI, -0.08 to 0.10; P = .72). Similarly, low-dose nesiritide had no significant effect on 72-hour cumulative urine volume (nesiritide, 8574 mL; 95% CI, 8014-9134 vs placebo, 8296 mL; 95% CI, 7762-8830; difference, 279 mL; 95% CI, -618 to 1176 mL; P = .49) or on the change in cystatin C level (nesiritide, 0.07 mg/L; 95% CI, 0.01-0.13 vs placebo, 0.11 mg/L; 95% CI, 0.06-0.16; difference, -0.04; 95% CI, -0.13 to 0.05; P = .36). Compared with placebo, there was no effect of low-dose dopamine or nesiritide on secondary end points reflective of decongestion, renal function, or clinical outcomes.

CONCLUSION AND RELEVANCE

In participants with acute heart failure and renal dysfunction, neither low-dose dopamine nor low-dose nesiritide enhanced decongestion or improved renal function when added to diuretic therapy.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01132846.

Human cardiovascular disease IBC chip-wide association with weight loss and weight regain in the look AHEAD trial

BACKGROUND/AIMS

The present study identified genetic predictors of weight change during behavioral weight loss treatment.

METHODS

Participants were 3,899 overweight/obese individuals with type 2 diabetes from Look AHEAD, a randomized controlled trial to determine the effects of intensive lifestyle intervention (ILI), including weight loss and physical activity, relative to diabetes support and education, on cardiovascular outcomes. Analyses focused on associations of single nucleotide polymorphisms (SNPs) on the Illumina CARe iSelect (IBC) chip (minor allele frequency >5%; n = 31,959) with weight change at year 1 and year 4, and weight regain at year 4, among individuals who lost ≥ 3% at year 1.

RESULTS

Two novel regions of significant chip-wide association with year-1 weight loss in ILI were identified (p < 2.96E-06). ABCB11 rs484066 was associated with 1.16 kg higher weight per minor allele at year 1, whereas TNFRSF11A, or RANK, rs17069904 was associated with 1.70 kg lower weight per allele at year 1.

CONCLUSIONS

This study, the largest to date on genetic predictors of weight loss and regain, indicates that SNPs within ABCB11, related to bile salt transfer, and TNFRSF11A, implicated in adipose tissue physiology, predict the magnitude of weight loss during behavioral intervention. These results provide new insights into potential biological mechanisms and may ultimately inform weight loss treatment.

Do genetic modifiers of high-density lipoprotein cholesterol and triglyceride levels also modify their response to a lifestyle intervention in the setting of obesity and type-2 diabetes mellitus?: The Action for Health in Diabetes (Look AHEAD) study

BACKGROUND

High-density lipoprotein cholesterol (HDL-C) and triglycerides are cardiovascular risk factors susceptible to lifestyle behavior modification and genetics. We hypothesized that genetic variants identified by genome-wide association studies as associated with HDL-C or triglyceride levels modify 1-year treatment response to an intensive lifestyle intervention, relative to a usual care of diabetes mellitus support and education.

METHODS AND RESULTS

We evaluated 82 single-nucleotide polymorphisms, which represent 31 loci demonstrated by genome-wide association studies to be associated with HDL-C and triglycerides, in 3561 participants who consented for genetic studies and met eligibility criteria. Variants associated with higher baseline HDL-C levels, cholesterol ester transfer protein (CETP) rs3764261 and hepatic lipase (LIPC) rs8034802, were found to be associated with HDL-C increases with intensive lifestyle intervention (P=0.0038 and 0.013, respectively) and had nominally significant treatment interactions (P=0.047 and 0.046, respectively). The fatty acid desaturase-2 rs1535 variant, associated with low baseline HDL-C (P=0.017), was associated with HDL-C increases with intensive lifestyle intervention (0.0037) and had a nominal treatment interaction (P=0.035). Apolipoprotein B (rs693) and LIPC (rs8034802) single-nucleotide polymorphisms showed nominally significant associations with HDL-C and triglyceride changes with intensive lifestyle intervention and a treatment interaction (P<0.05). Phosphatidylglycerophosphate synthase-1 single-nucleotide polymorphisms (rs4082919) showed the most significant triglyceride treatment interaction in the full cohort (P=0.0009).

CONCLUSIONS

This is the first study to identify genetic variants modifying lipid responses to a randomized lifestyle behavior intervention in overweight or obese individuals with diabetes mellitus. The effects of genetic factors on lipid changes may differ from the effects on baseline lipids and are modifiable by behavioral intervention.

Association of OPRM1 and COMT single-nucleotide polymorphisms with hospital length of stay and treatment of neonatal abstinence syndrome

IMPORTANCE

Neonatal abstinence syndrome (NAS) caused by in utero opioid exposure is a growing problem; genetic factors influencing the incidence and severity have not been previously examined. Single-nucleotide polymorphisms (SNPs) in the μ-opioid receptor (OPRM1), multidrug resistance (ABCB1), and catechol-o-methyltransferase (COMT) genes are associated with risk for opioid addiction in adults.

OBJECTIVE

To determine whether SNPs in the OPRM1, ABCB1, and COMT genes are associated with length of hospital stay and the need for treatment of NAS.

DESIGN, SETTING, AND PARTICIPANTS

Prospective multicenter cohort study conducted at 5 tertiary care centers and community hospitals in Massachusetts and Maine between July 2011 and July 2012. DNA samples were genotyped for SNPs, and then NAS outcomes were correlated with genotype. Eighty-six of 140 eligible mother-infant dyads were enrolled. Infants were eligible if they were 36 weeks' gestational age or older and exposed to methadone or buprenorphine in utero .

MAIN OUTCOMES AND MEASURES

Primary outcome measure was length of hospital stay, with between-group differences expressed as β and calculated with linear regression models. Secondary outcome measures included need for any medical treatment for NAS and treatment with 2 or more medications.

RESULTS

Infants with the OPRM1 118A>G AG/GG genotype had shortened length of stay (β = -8.5 days; 95% CI, -14.9 to -2.1 days; P = .009) and were less likely to receive any treatment than AA infants (48% vs 72%; adjusted odds ratio, 0.76; 95% CI, 0.63-0.96; P = .006). The COMT 158A>G AG/GG genotype was associated with shortened length of stay (β = -10.8 days; 95% CI, -18.2 to -3.4 days; P = .005) and less treatment with 2 or more medications (18% vs 56%; adjusted odds ratio, 0.68; 95% CI, 0.55-0.86; P = .001) than the AA genotype. Associations with the ABCB1 SNPs were not significant.

CONCLUSIONS AND RELEVANCE

Among infants with NAS, variants in the OPRM1 and COMT genes were associated with a shorter length of hospital stay and less need for treatment. These preliminary findings may provide insight into the mechanisms underlying NAS.

Augmentation index and aortic stiffness in bicuspid aortic valve patients with non-dilated proximal aortas

Background

We compared aortic stiffness, aortic impedance and pressure from wave reflections in the setting of bicuspid aortic valve (BAV) to the tricuspid aortic valve (TAV) in the absence of proximal aortic dilation. We hypothesized BAV is associated with abnormal arterial stiffness.

Methods

Ten BAV subjects (47 ± 4 years, 6 male) and 13 TAV subjects (46 ± 4 years, 10 male) without significant aortic valve disease were prospectively recruited. Characteristic impedance (Zc) was derived from echocardiographic images and pulse wave Doppler of the left ventricular outflow tract. Applanation tonometry was performed to obtain pulse wave velocity (PWV) at several sites as measures of arterial stiffness and augmentation index (AIx) as a measure of wave reflection.

Results

There were no significant differences between BAV and TAV subjects with regard to heart rate or blood pressure. Zc was similar between BAV and TAV subjects (p=0.25) as was carotid-femoral pulse wave velocity (cf-PWV) and carotid-radial PWV (cr-PWV) between BAV and TAV subjects (p=0.99). Carotid AIx was significantly higher in BAV patients compared with TAV patients (14.3 ± 4.18% versus -3.02 ± 3.96%, p=0.007).

Conclusions

Aortic stiffness and impedance is similar between subjects with BAV and TAV with normal aortic dimensions. The significantly higher carotid AIx in BAV, a proxy of increased pressure from wave reflections, may reflect abnormal vascular function distal to the aorta.

Genetic polymorphisms associated with carotid artery intima-media thickness and coronary artery calcification in women of the Kronos Early Estrogen Prevention Study

Menopausal hormone treatment (MHT) may limit progression of cardiovascular disease (CVD) but poses a thrombosis risk. To test targeted candidate gene variation for association with subclinical CVD defined by carotid artery intima-media thickness (CIMT) and coronary artery calcification (CAC), 610 women participating in the Kronos Early Estrogen Prevention Study (KEEPS), a clinical trial of MHT to prevent progression of CVD, were genotyped for 13,229 single nucleotide polymorphisms (SNPs) within 764 genes from anticoagulant, procoagulant, fibrinolytic, or innate immunity pathways. According to linear regression, proportion of European ancestry correlated negatively, but age at enrollment and pulse pressure correlated positively with CIMT. Adjusting for these variables, two SNPs, one on chromosome 2 for MAP4K4 gene (rs2236935, β = 0.037, P value = 2.36 × 10(-06)) and one on chromosome 5 for IL5 gene (rs739318, β = 0.051, P value = 5.02 × 10(-05)), associated positively with CIMT; two SNPs on chromosome 17 for CCL5 (rs4796119, β = -0.043, P value = 3.59 × 10(-05); rs2291299, β = -0.032, P value = 5.59 × 10(-05)) correlated negatively with CIMT; only rs2236935 remained significant after correcting for multiple testing. Using logistic regression, when we adjusted for waist circumference, two SNPs (rs11465886, IRAK2, chromosome 3, OR = 3.91, P value = 1.10 × 10(-04); and rs17751769, SERPINA1, chromosome 14, OR = 1.96, P value = 2.42 × 10(-04)) associated positively with a CAC score of >0 Agatston unit; one SNP (rs630014, ABO, OR = 0.51, P value = 2.51 × 10(-04)) associated negatively; none remained significant after correcting for multiple testing. Whether these SNPs associate with CIMT and CAC in women randomized to MHT remains to be determined.

Formin homology 2 domain containing 3 variants associated with hypertrophic cardiomyopathy

BACKGROUND

Incomplete penetrance and variable expression of hypertrophic cardiomyopathy (HCM) is well appreciated. Common genetic polymorphisms variants that may affect HCM penetrance and expression have been predicted but are not well established.

METHODS AND RESULTS

We performed a case-control genomewide association study to identify common HCM-associated genetic polymorphisms and then asked whether such common variants were more represented in HCM or could explain the heterogeneity of HCM phenotypes. We identified an intronic FHOD3 variant (rs516514) associated with HCM (odds ratio, 2.45; 95% confidence interval, 1.76-3.41; P=1.25×10(-7)) and validated this finding in an independent cohort. Next, we tested FHOD3-V1151I (rs2303510), a nonsynonymous variant in partial linkage disequilibrium with rs516514, and we detected an even stronger association with HCM (P=1.76×10(-9)). Although HCM patients were more likely to carry these, FHOD3 allele subjects homozygous for FHOD3-1151I had similar HCM phenotypes as carriers of the V1151 allele. FHOD3 expression is increased in the setting of HCM, and both alleles of FHOD3-V1151I were detected in HCM myectomy tissue. Previously, FHOD3 was found to be required for formation of the sarcomere, and here we demonstrate that its fly homolog fhos is required for normal adult heart systolic contraction.

CONCLUSIONS

Here we demonstrate the association of a common nonsynonymous FHOD3 genetic variant with HCM. This discovery further strengthens the potential role of gene mutations and polymorphisms that alter the amino acid sequence of sarcomere proteins and HCM.

Biogeographic ancestry, self-identified race, and admixture-phenotype associations in the Heart SCORE Study

Large epidemiologic studies examining differences in cardiovascular disease (CVD) risk factor profiles between European Americans and African Americans have exclusively used self-identified race (SIR) to classify individuals. Recent genetic epidemiology studies of some CVD risk factors have suggested that biogeographic ancestry (BGA) may be a better predictor of CVD risk than SIR. This hypothesis was investigated in 464 African Americans and 771 European Americans enrolled in the Heart Strategies Concentrating on Risk Evaluation (Heart SCORE) Study in March and April 2010. Individual West African and European BGA were ascertained by means of a panel of 1,595 genetic ancestry informative markers. Individual BGA varied significantly among African Americans and to a lesser extent among European Americans. In the total cohort, BGA was not found to be a better predictor of CVD risk factors than SIR. Both measures predicted differences in the presence of the metabolic syndrome, waist circumference, triglycerides, body mass index, very low density lipoprotein cholesterol, lipoprotein A, and systolic and diastolic blood pressure between European Americans and African Americans. These results suggest that for most nongenetic cardiovascular epidemiology studies, SIR is sufficient for predicting CVD risk factor differences between European Americans and African Americans. However, higher body mass index and diastolic blood pressure were significantly associated with West African BGA among African Americans, suggesting that BGA should be considered in genetic cardiovascular epidemiology studies carried out among African Americans.

Obesity susceptibility loci and dietary intake in the Look AHEAD Trial

BACKGROUND

Genome-wide association studies (GWAS) have identified consistent associations with obesity. However, the mechanisms remain unclear.

OBJECTIVE

The objective was to determine the association between obesity susceptibility loci and dietary intake.

DESIGN

The association of GWAS-identified obesity risk alleles (FTO, MC4R, SH2B1, BDNF, INSIG2, TNNI3K, NISCH-STAB1, MTIF3, MAP2K5, QPCTL/GIPR, and PPARG) with dietary intake, measured through food-frequency questionnaires, was investigated in 2075 participants from the Look AHEAD (Action for Health in Diabetes) clinical trial. We adjusted for age, sex, population stratification, and study site.

RESULTS

Obesity risk alleles at FTO rs1421085 significantly predicted more eating episodes per day (P = 0.001)-an effect that persisted after adjustment for body weight (P = 0.004). Risk variants within BDNF were significantly associated with more servings from the dairy product and the meat, eggs, nuts, and beans food groups (P ≤ 0.004). The risk allele at SH2B1 rs4788099 was significantly associated with more servings of dairy products (P = 0.001), whereas the risk allele at TNNI3K rs1514176 was significantly associated with a lower percentage of energy from protein (P = 0.002).

CONCLUSION

These findings suggest that obesity risk loci may affect the pattern and content of food consumption among overweight or obese individuals with type 2 diabetes. The Look AHEAD Genetic Ancillary Study was registered at clinicaltrials.gov as NCT01270763 and the Look AHEAD study as NCT00017953.

Evaluation of new and established age-related macular degeneration susceptibility genes in the Women's Health Initiative Sight Exam (WHI-SE) Study

PURPOSE

To assess whether established and newly reported genetic variants, independent of known lifestyle factors, are associated with the risk of age-related macular degeneration (AMD) among women participating in the Women's Health Initiative Sight Exam (WHI-SE) Genetic Ancillary Study.

DESIGN

Multicenter case-control study.

METHODS

One hundred and forty-six women with intermediate and late stages of AMD and 1269 subjects without AMD underwent ocular examinations and fundus photography to determine stage of AMD. Fourteen polymorphisms at or near 11 genes, including previously confirmed genes CFH, ARMS2/HTRA1, C2, C3, and CFI; recently reported AMD genes in the high-density lipoprotein cholesterol (HDL) pathway LIPC, ABCA1, CETP, and LPL; TIMP3/SYN3, a known ocular gene recently linked with AMD; and APOE, were assessed using logistic regression analysis.

RESULTS

After adjustment for demographic, behavioral, and other genetic factors, a protective effect was detected among TT carriers compared with non-carriers for the HDL pathway gene, LIPC rs493258, for intermediate and late AMD (OR [95% confidence interval]: 0.3 [0.2-0.7], P = .003). Variants in CFH rs1410996, ARMS2/HTRA1 A69S, and C3 R102G were significantly associated with an increased risk of AMD. Individuals with the homozygous CFI rs10033900 TT genotype had a 2.9 [1.2-7.2]-fold increased risk, and those with the CFH Y402H GG genotype had a 2.2 [1.0-4.8]-fold higher risk of developing AMD compared with non-carriers. APOE4 carriers may have a reduced risk of intermediate/late AMD (OR = 0.5 [0.3-0.9], P = .015. Suggestive associations were seen between AMD and the HDL pathway genes CETP and LPL.

CONCLUSION

In this unique national cohort of women, we found associations with established AMD-related genetic factors and the recently reported LIPC gene in the HDL pathway. These findings may help develop novel therapeutic targets to treat or delay the onset of the disease.

ANGPTL4 variants E40K and T266M are associated with lower fasting triglyceride levels in Non-Hispanic White Americans from the Look AHEAD Clinical Trial

Background

Elevated triglyceride levels are a risk factor for cardiovascular disease. Angiopoietin-like protein 4 (Angptl4) is a metabolic factor that raises plasma triglyceride levels by inhibiting lipoprotein lipase (LPL). In non-diabetic individuals, the ANGPTL4 coding variant E40K has been associated with lower plasma triglyceride levels while the T266M variant has been associated with more modest effects on triglyceride metabolism. The objective of this study was to determine whether ANGPTL4 E40K and T266M are associated with triglyceride levels in the setting of obesity and T2D, and whether modification of triglyceride levels by these genetic variants is altered by a lifestyle intervention designed to treat T2D.

Methods

The association of ANGPTL4 E40K and T266M with fasting triglyceride levels was investigated in 2,601 participants from the Look AHEAD Clinical Trial, all of whom had T2D and were at least overweight. Further, we tested for an interaction between genotype and treatment effects on triglyceride levels.

Results

Among non-Hispanic White Look AHEAD participants, ANGPTL4 K40 carriers had mean triglyceride levels of 1.61 ± 0.62 mmol/L, 0.33 mmol/L lower than E40 homozygotes (p = 0.001). Individuals homozygous for the minor M266 allele (MAF 30%) had triglyceride levels of 1.75 ± 0.58 mmol/L, 0.24 mmol/L lower than T266 homozygotes (p = 0.002). The association of the M266 with triglycerides remained significant even after removing K40 carriers from the analysis (p = 0.002). There was no interaction between the weight loss intervention and genotype on triglyceride levels.

Conclusions

This is the first study to demonstrate that the ANGPTL4 E40K and T266M variants are associated with lower triglyceride levels in the setting of T2D. In addition, our findings demonstrate that ANGPTL4 genotype status does not alter triglyceride response to a lifestyle intervention in the Look AHEAD study.

Lack of association of Klotho gene variants with valvular and vascular calcification in Caucasians: a candidate gene study of the Framingham Offspring Cohort

BACKGROUND

Valvular and vascular calcification are important early aging phenotypes and represent risk factors for cardiovascular morbidity and mortality. Klotho is a gene primarily expressed in the kidney that has an important role in calcium-phosphate homeostasis. The functional KL-VS variant of Klotho has been associated with aging and cardiovascular disease in human studies, but its role in valvular and vascular calcification remains unknown. We performed a candidate gene study in the Framingham Offspring Cohort to evaluate the effect of KL-VS variant of the Klotho gene on valvular calcification.

METHODS

We analyzed the Klotho KL-VS genotype (rs9536314) from the Affymetrix 550K genome-wide dataset, distributed by dbGAP, on 1389 cases and 2139 controls from the Framingham Heart Study Offspring Cohort. Allele and genotype frequencies were compared between cases and controls. Valvular calcification was defined as presence of calcification on the mitral annulus or the aortic valve as determined by echocardiography. A sensitivity analysis of coronary artery calcification by electron beam computed tomography was performed on 1363 patients.

RESULTS

The frequency of the TT versus the TG allele was not different between the cases and the controls (39 versus 41%). The KL-VS variant of Klotho was not associated with valvular or vascular calcification, despite adequate power to detect association (86% for odds ratios ≥1.2). In sensitivity analyses, no association (P > 0.001) between other common variants of Klotho, β-Klotho or fibroblast growth factor-23 and the end points of valvular or vascular calcification was observed.

CONCLUSIONS

In our adequately powered candidate gene study, we did not observe an association with the functional KL-VS variant of Klotho and presence of valvular or vascular calcification. Future studies aimed at combining cohorts with echocardiographic phenotypes need to be conducted to identify genetic variants associated with valvular calcification.

Heterogeneity of the phenotypic definition of coronary artery disease and its impact on genetic association studies

BACKGROUND

Variability in phenotypic characterization of coronary artery disease (CAD) may contribute to the heterogeneity of genetic association studies, and more consistency in phenotype definitions might improve replication of genetic associations. We assessed the extent of phenotypic heterogeneity and quantified its impact in a large literature sample of association studies.

METHODS AND RESULTS

We searched for large (≥15 studies) meta-analyses of genetic associations and reviewed all studies included therein. From each primary study, we extracted phenotypic definitions, demographics, study design characteristics, and genotypic data. For each association, we assessed the magnitude and heterogeneity of genetic effects within and across CAD phenotypes, using meta-analytic methodologies. A total of 965 individual studies investigating 32 distinct variants in 22 genes were included, from which we grouped CAD phenotypes into 3 categories: acute coronary syndromes (ACS) (426 [44%] studies); angiographically documented disease (323 [34%] studies); and broad, not otherwise specified CAD (216 [22%] studies). These clinical phenotypes were overlapping. Subgroup meta-analyses by phenotype showed discordant results, but phenotypic classification generally explained small proportions of between-study heterogeneity. Differences between phenotypic groups were minimized for associations with robust statistical support. No CAD phenotype was consistently associated with larger or more homogeneous genetic effects in meta-analyses.

CONCLUSIONS

Substantial phenotypic heterogeneity exists in CAD genetic associations, but differences in phenotype definition make a small contribution to between-study heterogeneity. We did not find a consistent effect in terms of the magnitude or homogeneity of summary effects for a specific phenotype to support its preferential use in genetic studies or meta-analyses for CAD.

Cardiac-specific overexpression of dominant-negative CREB leads to increased mortality and mitochondrial dysfunction in female mice

Cardiac failure is associated with diminished activation of the transcription factor cyclic nucleotide regulatory element binding-protein (CREB), and heart-specific expression of a phosphorylation-deficient CREB mutant in transgenic mice [dominant negative CREB (dnCREB) mice] recapitulates the contractile phenotypes of cardiac failure (Fentzke RC, Korcarz CE, Lang RM, Lin H, Leiden JM. Dilated cardiomyopathy in transgenic mice expressing a dominant-negative CREB transcription factor in the heart. J Clin Invest 101: 2415-2426, 1998). In the present study, we demonstrated significantly elevated mortality and contractile dysfunction in female compared with male dnCREB mice. Female dnCREB mice demonstrated a 21-wk survival of only 17% compared with 67% in males (P < 0.05) and exclusively manifest decreased cardiac peroxisome proliferator-activated receptor-γ coactivator-1α and estrogen-related receptor-α content, suggesting sex-related effects on cardiac mitochondrial function. Hearts from 4-wk-old dnCREB mice of both sexes demonstrated diminished mitochondrial respiratory capacity compared with nontransgenic controls. However, by 12 wk of age, there was a significant decrease in mitochondrial density (citrate synthase activity) and deterioration of mitochondrial structure, as demonstrated by transmission electron microscopy, in female dnCREB mice, which were not found in male transgenic littermates. Subsarcolemmal mitochondria isolated from hearts of female, but not male, dnCREB mice demonstrated increased ROS accompanied by decreases in the expression/activity of the mitochondrial antioxidants MnSOD and glutathione peroxidase. These results demonstrate that heart-specific dnCREB expression results in mitochondrial respiratory dysfunction in both sexes; however, increased oxidant burden, reduced antioxidant expression, and disrupted mitochondrial structure are exacerbated by the female sex, preceding and contributing to the greater contractile morbidity and mortality. These results provide further support for the role of the CREB transcription factor in regulating mitochondrial integrity and identify a critical pathway that may contribute to sex differences in heart failure.

The μ-opioid receptor variant N190K is unresponsive to peptide agonists yet can be rescued by small-molecule drugs

The μ-opioid receptor (MOR) plays an important role in modulating analgesia, feeding behavior, and a range of autonomic functions. In the current study, we investigated the degree to which 13 naturally occurring missense mutations affect the pharmacological properties of the human MOR. After expression of each receptor in human embryonic kidney 293 cells, signaling (Gα(i/o)-mediated) induced by peptide agonists was assessed using luciferase reporter gene assays. Multiple mutants (S66F, S147C, R260H, R265C, R265H, and S268P) show a significant reduction in agonist potency. At the N190K variant, agonist-mediated signaling was essentially absent. Enzyme-linked immunosorbent assay, microscopic analysis, and radioligand binding assays revealed that this mutant shows markedly reduced cell-surface expression, whereas all other receptor variants were expressed at normal levels. Surface expression of the N190K variant could be increased by incubation with the alkaloid agonist buprenorphine or with either naltrexone or naloxone, structurally related MOR antagonists. We were surprised to find that both putative antagonists, despite being inactive at the wild-type MOR, triggered a concentration-dependent increase in N190K receptor-mediated signaling. In contrast, peptidic ligands failed to promote expression or rescue function of the N190K mutant. Subsequent analysis of the N190K variant in an ethnically diverse cohort identified this isoform in a subgroup of African Americans. Taken together, our studies reveal that the N190K mutation leads to severe functional alterations and, in parallel, changes the response to established MOR ligands. The extent to which this mutation results in physiological abnormalities or affects drug sensitivity in selected populations (e.g., those with chronic pain or addiction) remains to be investigated.

Little ROCK is a ROCK1 pseudogene expressed in human smooth muscle cells

Background

Sequencing of the human genome has identified numerous chromosome copy number additions and subtractions that include stable partial gene duplications and pseudogenes that when not properly annotated can interfere with genetic analysis. As an example of this problem, an evolutionary chromosome event in the primate ancestral chromosome 18 produced a partial duplication and inversion of rho-associated protein kinase 1 (ROCK1 -18q11.1, 33 exons) in the subtelomeric region of the p arm of chromosome 18 detectable only in humans. ROCK1 and the partial gene copy, which the gene databases also currently call ROCK1, include non-unique single nucleotide polymorphisms (SNPs).

Results

Here, we characterize this partial gene copy of the human ROCK1, termed Little ROCK, located at 18p11.32. Little ROCK includes five exons, four of which share 99% identity with the terminal four exons of ROCK1 and one of which is unique to Little ROCK. In human while ROCK1 is expressed in many organs, Little ROCK expression is restricted to vascular smooth muscle cell (VSMC) lines and organs rich in smooth muscle. The single nucleotide polymorphism database (dbSNP) lists multiple variants contained in the region shared by ROCK1 and Little ROCK. Using gene and cDNA sequence analysis we clarified the origins of two non-synonymous SNPs annotated in the genome to actually be fixed differences between the ROCK1 and the Little ROCK gene sequences. Two additional coding SNPs were valid polymorphisms selectively within Little ROCK. Little ROCK-Green Fluorescent fusion proteins were highly unstable and degraded by the ubiquitin-proteasome system in vitro.

Conclusion

In this report we have characterized Little ROCK (ROCK1P1), a human expressed pseudogene derived from partial duplication of ROCK1. The large number of pseudogenes in the human genome creates significant genetic diversity. Our findings emphasize the importance of taking into consideration pseudogenes in all candidate gene and genome-wide association studies, as well as the need for complete annotation of human pseudogenome.

Application of gene network analysis techniques identifies AXIN1/PDIA2 and endoglin haplotypes associated with bicuspid aortic valve

Bicuspid Aortic Valve (BAV) is a highly heritable congenital heart defect. The low frequency of BAV (1% of general population) limits our ability to perform genome-wide association studies. We present the application of four a priori SNP selection techniques, reducing the multiple-testing penalty by restricting analysis to SNPs relevant to BAV in a genome-wide SNP dataset from a cohort of 68 BAV probands and 830 control subjects. Two knowledge-based approaches, CANDID and STRING, were used to systematically identify BAV genes, and their SNPs, from the published literature, microarray expression studies and a genome scan. We additionally tested Functionally Interpolating SNPs (fitSNPs) present on the array; the fourth consisted of SNPs selected by Random Forests, a machine learning approach. These approaches reduced the multiple testing penalty by lowering the fraction of the genome probed to 0.19% of the total, while increasing the likelihood of studying SNPs within relevant BAV genes and pathways. Three loci were identified by CANDID, STRING, and fitSNPS. A haplotype within the AXIN1-PDIA2 locus (p-value of 2.926x10(-06)) and a haplotype within the Endoglin gene (p-value of 5.881x10(-04)) were found to be strongly associated with BAV. The Random Forests approach identified a SNP on chromosome 3 in association with BAV (p-value 5.061x10(-06)). The results presented here support an important role for genetic variants in BAV and provide support for additional studies in well-powered cohorts. Further, these studies demonstrate that leveraging existing expression and genomic data in the context of GWAS studies can identify biologically relevant genes and pathways associated with a congenital heart defect.

Role of cyclic AMP-dependent kinase response element-binding protein in recombinant adeno-associated virus-mediated transduction of heart muscle cells

Recombinant adeno-associated virus (rAAV) vectors represent a promising approach to gene delivery for clinical use. Published data indicate that rAAV vector genomes persist in vivo as episomal chromatin in the skeletal muscle of nonhuman primates. In this study, we assessed the interconnection between the transcription factor cyclic AMP response element-binding protein (CREB) and recombinant AAV serotype 2 vector genomes after transduction in vitro and in vivo. rAAV-mediated myocyte transduction was potently blocked in the hearts of mice expressing CREB-S133A, which is a CREB-S133A dominant-negative mutant. Isoproterenol, a strong CREB activator, prominently increased rAAV transduction and the increase was abrogated by silencing the CREB gene with small interfering RNA. In addition, rAAV infection of muscle cells mildly but significantly induced CREB protein phosphorylation at serine-133, and was capable of stimulating CREB-dependent transcription from a reporter plasmid. Using chromatin immunoprecipitation and immunoblotting assays, both CREB and p300 were found to physically associate with two different rAAV genomes. Accordingly, CREB/p300 appears to have a role in rAAV transduction to establish active vector transcription in heart muscle cells.

Daxx inhibits muscle differentiation by repressing E2A-mediated transcription

The basic helix-loop-helix (HLH) E2A transcription factors bind to DNA as homodimers or as heterodimers formed with other basic HLH factors, activate gene expression, and promote differentiation of muscle, lymphoid, neuronal, and other cell types. These E2A functions can be inhibited by the Id proteins, HLH factors that sequester E2A in non-DNA binding dimers. Here we describe the direct interaction of E2A with Daxx, a broadly expressed non-HLH protein previously associated with apoptosis and transcriptional repression. Daxx inhibits E2A function, but not via an Id-like mechanism; rather, it recruits histone deacetylase activity to E2A-dependent promoters. Increased Daxx expression during muscle differentiation inhibits E2A-dependent expression of key myogenic genes and reduces myotube formation, while decreased Daxx expression promotes myotube formation. These results identify a new mechanism for limiting E2A activity and establish a link between Daxx-mediated gene regulation and control of cellular differentiation.

Deletion of GSK-3beta in mice leads to hypertrophic cardiomyopathy secondary to cardiomyoblast hyperproliferation

Based on extensive preclinical data, glycogen synthase kinase-3 (GSK-3) has been proposed to be a viable drug target for a wide variety of disease states, ranging from diabetes to bipolar disorder. Since these new drugs, which will be more powerful GSK-3 inhibitors than lithium, may potentially be given to women of childbearing potential, and since it has controversially been suggested that lithium therapy might be linked to congenital cardiac defects, we asked whether GSK-3 family members are required for normal heart development in mice. We report that terminal cardiomyocyte differentiation was substantially blunted in Gsk3b(-/-) embryoid bodies. While GSK-3alpha-deficient mice were born without a cardiac phenotype, no live-born Gsk3b(-/-) pups were recovered. The Gsk3b(-/-) embryos had a double outlet RV, ventricular septal defects, and hypertrophic myopathy, with near obliteration of the ventricular cavities. The hypertrophic myopathy was caused by cardiomyocyte hyperproliferation without hypertrophy and was associated with increased expression and nuclear localization of three regulators of proliferation - GATA4, cyclin D1, and c-Myc. These studies, which we believe are the first in mammals to examine the role of GSK-3alpha and GSK-3beta in the heart using loss-of-function approaches, implicate GSK-3beta as a central regulator of embryonic cardiomyocyte proliferation and differentiation, as well as of outflow tract development. Although controversy over the teratogenic effects of lithium remains, our studies suggest that caution should be exercised in the use of newer, more potent drugs targeting GSK-3 in women of childbearing age.

Increased FOG-2 in failing myocardium disrupts thyroid hormone-dependent SERCA2 gene transcription

Reduced expression of sarcoplasmic reticulum calcium ATPase (SERCA)2 and other genes in the adult cardiac gene program has raised consideration of an impaired responsiveness to thyroid hormone (T3) that develops in the advanced failing heart. Here, we show that human and murine cardiomyopathy hearts have increased expression of friend of GATA (FOG)-2, a cardiac nuclear hormone receptor corepressor protein. Cardiac-specific overexpression of FOG-2 in transgenic mice led to depressed cardiac function, activation of the fetal gene program, congestive heart failure, and early death. SERCA2 transcript and protein levels were reduced in FOG-2 transgenic hearts, and FOG-2 overexpression impaired T3-mediated SERCA2 expression in cultured cardiomyocytes. FOG-2 physically interacts with thyroid hormone receptor-alpha1 and abrogated even high levels of T3-mediated SERCA2 promoter activity. These results demonstrate that SERCA2 is an important target of FOG-2 and that increased FOG-2 expression may contribute to a decline in cardiac function in end-stage heart failure by impaired T3 signaling.

Variation in estrogen-related genes associated with cardiovascular phenotypes and circulating estradiol, testosterone, and dehydroepiandrosterone sulfate levels

BACKGROUND

Younger age at the onset of menopause and lower circulating levels of estrogen are risk factors for cardiovascular disease. Several studies have detected associations between variations in genes encoding estrogen receptors alpha (ESR1) and beta (ESR2), and enzyme aromatase (CYP19A1), which regulates the estrogen to testosterone ratio, and cardiovascular phenotypes in the Framingham Heart Study. To explore potential mechanisms by which these gene variants may contribute to cardiovascular disease, we tested the hypothesis that the polymorphisms were associated with endogenous steroid hormone levels.

METHODS

Multiple regression analysis was used to assess the relation between reported polymorphisms and total serum estradiol, testosterone, and dehydroepiandrosterone sulfate levels in 834 men and 687 women who attended the third and fourth Framingham Heart Study examination cycles.

RESULTS

In men, significant associations were detected between CYP19A1 polymorphisms and estradiol and testosterone levels, and the estradiol to testosterone ratio (P ranges 0.0005-0.01). Specifically, carriers of common haplotype rs700518[G]-(TTTA)(n) [L]-rs726547[C] had higher estradiol levels (5% per copy; P = 0.0004), lower testosterone levels (17% per copy; P = 0.036), and a higher estradiol to testosterone ratio (24% per copy; P < 0.0001) compared with the rs700518[A]-(TTTA)(n) [S]-rs726547[C] carriers. In addition, postmenopausal carriers of the ESR2 (CA)(n) long allele and rs1256031 [C] allele had moderately higher estradiol levels (P < or = 0.03). No significant associations with the ESR1 variants were detected.

CONCLUSIONS

Our findings suggest that variations in CYP19A1 correlate with steroid hormone levels in men. Knowledge that a specific carrier status may predispose to altered steroid hormone levels may lead to targeted intervention strategies to reduce health risks in genetically susceptible individuals.

The CREB leucine zipper regulates CREB phosphorylation, cardiomyopathy, and lethality in a transgenic model of heart failure

Signaling through cAMP plays an important role in heart failure. Phosphorylation of cAMP response element binding protein (CREB) at serine-133 regulates gene expression in the heart. We examined the functional significance of CREB-S133 phosphorylation by comparing transgenic models in which a phosphorylation resistant CREB-S133A mutant containing either an intact or a mutated leucine zipper domain (CREB-S133A-LZ) was expressed in the heart. In vitro, CREB-S133A retained the ability to interact with wild-type CREB, whereas CREB-S133A-LZ did not. In vivo, CREB-S133A and CREB-S133A-LZ were expressed at comparable levels in the heart; however, CREB-S133A markedly suppressed the phosphorylation of endogenous CREB, whereas CREB-S133A-LZ had no effect. The one-year survival of mice from two CREB-S133A-LZ transgenic lines was equivalent to nontransgenic littermate control mice (NTG), whereas transgenic CREB-S133A mice died with heart failure at a median 30 wk of age (P < 0.0001). CREB-S133A mice had an altered gene expression characteristic of the failing heart, whereas CREB-S133A-LZ mice did not. Left ventricular contractile function was substantially reduced in CREB-S133A mice versus NTG mice and only modestly reduced in CREB-S133A-LZ mice (P < 0.02). When considered in light of other studies, these findings indicate that overexpression of the CREB leucine zipper is required for both inhibition of endogenous CREB phosphorylation and cardiomyopathy in this murine model of heart failure.

Age-related changes in echocardiographic measurements: association with variation in the estrogen receptor-alpha gene

Left ventricular (LV) mass and other LV measures have been shown to be heritable. In this study we hypothesized that functional variation in the gene coding for estrogen receptor-alpha (ESR1), known for mediating the effect of estrogens on myocardium, is associated with age-related changes in LV structure. Four genetic markers (ESR1 TA repeat; rs2077647, or +30T>C; rs2234693, or PvuII; and rs9340799, or XbaI) were genotyped in 847 unrelated individuals (488 women) from the Framingham Offspring Study, who attended 2 examination cycles 16 years apart (mean ages at first examination: 43+/-9 years; at follow-up: 59+/-9 years). ANCOVA was used to assess the association of polymorphisms and their haplotypes with cross-sectional measurements and longitudinal changes in LV mass, wall thickness, end-diastolic and end-systolic internal diameter, and fractional shortening after adjustment for factors known to influence these variables. Changes over time were detected for all of the LV measurements (P ranging from <0.0001 to 0.02), except for fractional shortening in men. The SS genotype of the ESR1 TA repeat polymorphism in the promoter region was associated with longitudinal changes in LV mass and LV wall thickness (P ranging from 0.0006 to 0.01). Moreover, the TA[S]-+30[T]-PvuII[T]-XbaI[A] haplotype (frequency: 47.5%) was associated with greater LV changes as compared with the TA[L]-+30[C]-PvuII[C]-XbaI[G] haplotype (frequency: 31.8%). Our results are consistent with the hypothesis that common ESR1 polymorphisms are significantly associated with age-related changes in LV structure. Understanding the mechanisms predisposing to unfavorable LV remodeling of the heart with advancing age may aid in the discovery of new therapeutic targets for the prevention of heart failure.

GATA5 Activation of the Progesterone Receptor Gene Promoter in Breast Cancer Cells Is Influenced by the +331G/A Polymorphism

Previously, a modest association was observed between the progesterone receptor +331G/A gene variant and breast cancer risk. Here, in a larger sample of breast cancer cases and controls (n = 1,322/n = 1,953) nested in the Nurses' Health Study cohort, we confirm a significant association (odds ratio, 1.41; 95% confidence interval, 1.10-1.79) and suggest a molecular model. The association of the +331G/A variant with breast cancer was particularly strong among obese women (body mass index > 30; odds ratio, 2.87; 95% confidence interval, 1.40-5.90). To help understand the molecular mechanism by which this variant may predispose women to breast cancer, we identified nearby transcription factor binding sites. This search predicted a binding site for the GATA family of transcriptional regulators adjacent to this hPR polymorphism. Importantly, we found GATA3, GATA4, and GATA6 are expressed in normal breast tissue and two breast cancer cell lines, whereas GATA5 is minimally expressed in normal mammary tissue and more strongly expressed in two breast cancer cell lines. This finding was relevant because GATA5 bound the site adjacent to the +331G/A polymorphism, and activated the hPR (-711 to +822)-luciferase reporter plasmid in breast cancer cells. Overexpression of GATA5 increased expression of the endogenous hPR transcript, and GATA5 more strongly activated an hPR promoter construct encoding the PR-B isoform. Finally, hPR promoter constructs including the +331A were more strongly activated by GATA5 than constructs including +331G. Our findings suggest that GATA5 interacts with the +331G/A polymorphism to stimulate hPR-B expression in mammary cells, which may contribute to breast cancer susceptibility.

A functional polymorphism in the promoter of the progesterone receptor gene associated with endometrial cancer risk

Excessive estrogen stimulation unopposed by progesterone strongly predisposes to endometrial cancer. Because the antiproliferative effect of progesterone requires the progesterone receptor (PR), which exists in two isoforms, PR-A and -B, we reasoned that variants in the PR gene may predispose to endometrial cancer. We found six variable sites, including four polymorphisms in the hPR gene and five common haplotypes. One promoter region polymorphism, +331G/A, creates a unique transcription start site. Biochemical assays showed that the +331G/A polymorphism increases transcription of the PR gene, favoring production of hPR-B in an endometrial cancer cell line. Using a case-control study nested within the Nurses' Health Study cohort, we observed a statistically significant association between the +331G/A polymorphism and the risk of endometrial cancer, which was even greater in overweight women carriers. After including a second population of controls, these associations remained intact. Our findings suggest that the +331G/A hPR gene polymorphism may contribute to endometrial cancer risk by increasing expression of the hPR-B isoform.

Cardiomyocyte-specific gene expression following recombinant adeno-associated viral vector transduction

Recombinant adeno-associated viral (rAAV) vectors hold promise for delivering genes for heart diseases, but cardiac-specific expression by the use of rAAV has not been demonstrated. To achieve this goal rAAV vectors were generated expressing marker or potentially therapeutic genes under the control of the cardiac muscle-specific alpha myosin heavy chain (MHC) gene promoter. The rAAV-MHC vectors expressed in primary cardiomyocytes with similar kinetics to rAAV-CMV; however, expression by the rAAV-MHC vectors was restricted to cardiomyocytes. rAAV vectors have low cytotoxicity, and it is demonstrated here that rAAV fails to induce apoptosis in cardiomyocytes compared with a recombinant adenoviral vector. rAAV-MHC or rAAV-CMV vectors were administered to mice to determine the specificity of expression in vivo. The rAAV-MHC vectors expressed specifically in cardiomyocytes, whereas the control rAAV-CMV vector expressed in heart, skeletal muscle, and brain. rAAV-MHC transduction resulted in long term (16 weeks) expression of human growth hormone following intracardiac, yet not intramuscular, injection. Finally, we defined the minimal MHC enhancer/promoter sequences required for specific and robust in vivo expression in the context of a rAAV vector. For the first time we describe a panel of rAAV vectors capable of long term cardiac specific expression of intracellular and secreted proteins.

Friend of GATA 2 physically interacts with chicken ovalbumin upstream promoter-TF2 (COUP-TF2) and COUP-TF3 and represses COUP-TF2-dependent activation of the atrial natriuretic factor promoter

Friend of GATA (FOG)-2 is a multi-zinc finger transcriptional corepressor protein that binds specifically to GATA4. Gene targeting studies have demonstrated that FOG-2 is required for normal cardiac morphogenesis, including the development of the coronary vasculature, left ventricular compact zone, and heart valves. To better understand the molecular mechanisms by which FOG-2 regulates these cardiac developmental programs, we screened a mouse day 11 embryo library using a yeast two-hybrid interaction trap with the fifth and sixth zinc fingers of FOG-2 as bait. Using this approach, we isolated clones encoding the orphan nuclear receptors chicken ovalbumin upstream promoter-transcription factor (COUP-TF) 2 and COUP-TF3. COUP-TF2-null embryos die during embryonic development with defective angiogenesis and cardiac defects, a pattern that partly resembles the FOG-2-null phenotype. The interaction between COUP-TF2 and FOG-2 in mammalian cells was confirmed by co-immunoprecipitation of these proteins from transfected COS-7 cells. The sites of binding interaction between COUP-TF2 and FOG-2 were mapped to zinc fingers 5 and 6 and fingers 7 and 8 of FOG-2 and to the carboxyl terminus of the COUP-TF proteins. Binding to COUP-TF2 was specific because FOG-2 did not interact with the ligand-binding domains of retinoid X receptor alpha, glucocorticoid receptor, and peroxisome proliferating antigen receptor gamma, which are related to the COUP-TF proteins. Full-length FOG-2 markedly enhanced transcriptional repression by GAL4-COUP-TF2(117-414), but not by a COUP-TF2 repression domain mutant. Moreover, FOG-2 repressed COUP-TF2dependent synergistic activation of the atrial natriuretic factor promoter by both GATA4 and the FOG-2-independent mutant GATA4-E215K. Taken together, these findings suggest that FOG-2 functions as a corepressor for both GATA and COUP-TF proteins.

Thioredoxin facilitates the induction of heme oxygenase-1 in response to inflammatory mediators

Heme oxygenase (HO)-1 is a stress response protein that is regulated by oxidative stress. HO-1 catalyzes the generation of biliverdin, carbon monoxide, and iron from heme. Lipopolysaccharide (LPS) and interleukin (IL)-1beta induce HO-1 through the binding of nuclear proteins to AP-1 motifs in enhancer regions upstream from the transcription start site. The DNA binding activity of AP-1 proteins depends on the reduction of cysteines in their DNA-binding domains. We found that agents that disrupt free sulfhydryl groups abolish AP-1 binding activity in nuclear proteins obtained from rat aortic smooth muscle cells and macrophages stimulated with IL-1beta or LPS. Thioredoxin (TRX) may regulate the redox status of nuclear transcription factors in response to oxidative stimuli, thus we determined the role of TRX in the physiologic regulation of HO-1. TRX underwent nuclear translocation in cells stimulated with IL-1beta and LPS. We transfected macrophages with a heterologous promoter construct containing two AP-1 sites from an upstream enhancer region in the HO-1 promoter. Recombinant TRX induced promoter activity to a level analogous to that induced by LPS, and this TRX response was abolished by mutation of the AP-1 sites. An inhibitor of TRX reductase, used to prevent TRX translocation in the reduced state, decreased HO-1 induction by IL-1beta and LPS. These data provide the first evidence that TRX contributes to the induction of HO-1 by inflammatory mediators.

A functionally conserved N-terminal domain of the friend of GATA-2 (FOG-2) protein represses GATA4-dependent transcription

GATA4 is a transcriptional activator of cardiac-restricted promoters and is required for normal cardiac morphogenesis. Friend of GATA-2 (FOG-2) is a multizinc finger protein that associates with GATA4 and represses GATA4-dependent transcription. To better understand the transcriptional repressor activity of FOG-2 we performed a functional analysis of the FOG-2 protein. The results demonstrated that 1) zinc fingers 1 and 6 of FOG-2 are each capable of interacting with evolutionarily conserved motifs within the N-terminal zinc finger of mammalian GATA proteins, 2) a nuclear localization signal (RKRRK) (amino acids 736-740) is required to program nuclear targeting of FOG-2, and 3) FOG-2 can interact with the transcriptional co-repressor, C-terminal-binding protein-2 via a conserved sequence motif in FOG-2 (PIDLS). Surprisingly, however, this interaction with C-terminal-binding protein-2 is not required for FOG-2-mediated repression of GATA4-dependent transcription. Instead, we have identified a novel N-terminal domain of FOG-2 (amino acids 1-247) that is both necessary and sufficient to repress GATA4-dependent transcription. This N-terminal repressor domain is functionally conserved in the related protein, Friend of GATA1. Taken together, these results define a set of evolutionarily conserved mechanisms by which FOG proteins repress GATA-dependent transcription and thereby form the foundation for genetic studies designed to elucidate the role of FOG-2 in cardiac development.

A syndrome of tricuspid atresia in mice with a targeted mutation of the gene encoding Fog-2

Tricuspid atresia (TA) is a common form of congenital heart disease, accounting for 1-3% of congenital cardiac disorders. TA is characterized by the congenital agenesis of the tricuspid valve connecting the right atrium to the right ventricle and both an atrial septal defect (ASD) and a ventricular septal defect (VSD). Some patients also have pulmonic stenosis, persistence of a left-sided superior vena cava or transposition of the great arteries. Most cases of TA are sporadic, but familial occurrences with disease in multiple siblings have been reported. Gata4 is a zinc-finger transcription factor with a role in early cardiac development. Gata4-deficient mice fail to form a ventral heart tube and die of circulatory failure at embryonic day (E) 8.5 (refs 6,7). Zfpm2 (also known as Fog-2) is a multi-zinc-finger protein that is co-expressed with Gata4 in the developing heart beginning at E8.5 (refs 8-10). Zfpm2 interacts specifically with the N-terminal zinc finger of Gata4 and represses Gata4-dependent transcription. Here we use targeted mutagenesis to explore the role of Zfpm2 in normal cardiac development. Zfpm2-deficient mice died of congestive heart failure at E13 with a syndrome of tricuspid atresia that includes an absent tricuspid valve, a large ASD, a VSD, an elongated left ventricular outflow tract, rightward displacement of the aortic valve and pulmonic stenosis. These mice also display hypoplasia of the compact zone of the left ventricle. Our findings indicate the importance of Zfpm2 in the normal looping and septation of the heart and suggest a genetic basis for the syndrome of tricuspid atresia.

Role of activating protein-1 and high mobility group-I(Y) protein in the induction of CD44 gene expression by interleukin-1beta in vascular smooth muscle cells

CD44 is a multifunctional cell adhesion molecule that participates in pathological states such as inflammation and tumorigenesis. CD44 is induced on vascular smooth muscle cells after arterial wall injury and may mediate their proliferation and migration into the neointima during arteriosclerosis. We have demonstrated elsewhere that the proinflammatory cytokine interleukin (IL)-1beta up-regulates CD44 mRNA and protein expression in cultured rat aortic smooth muscle cells (RASMC) by increasing gene transcription. By transient transfection of 5'-deletion constructs into RASMC, we show in the present study that a conserved AP-1 site 110 base pairs from the transcription start site of the mouse CD44 promoter is important for basal activity. Mutation of the AP-1 site significantly reduced induction of promoter activity by IL-1beta, and electrophoretic mobility shift assays demonstrated that Fos and c-Jun were present in the CD44 AP-1 binding complex after IL-1beta stimulation. In addition, cotransfection of the architectural transcription factor high mobility group (HMG)-I(Y) protein with c-Fos and c-Jun markedly increased trans-activation of the CD44 promoter. Taken together, our studies demonstrate that AP-1 proteins are a central regulatory component used by IL-1beta to modulate expression of CD44 during an inflammatory response in vascular smooth muscle cells and that transcription of CD44 by AP-1 proteins is enhanced by HMG-I(Y). -Foster, L. C., Wiesel, P., Huggins, G. S, Pañares, R., Chin, M. T., Pellacani, A., Perrella, M. A. Role of activating protein-1 and high mobility group-I(Y) protein in the induction of CD44 gene expression by interleukin-1beta in vascular smooth muscle cells.

Induction of high mobility group I architectural transcription factors in proliferating vascular smooth muscle in vivo and in vitro

Proliferation of vascular smooth muscle cells (VSMCs) is a hallmark of arteriosclerosis. Architectural transcription factors of the high mobility group (HMG)-I family have been implicated in the control of cell proliferation and gene expression. We studied the pattern of HMG-I mRNA and protein expression in proliferating VSMCs. HMG-I(Y) and HMGI-C mRNAs were barely detectable by Northern analysis in samples prepared from uninjured rat carotid arteries. In contrast, these mRNAs were induced dramatically in carotid arteries 2 and 5-6 days after balloon injury. By in situ hybridization at 6 days after injury, the induced mRNAs localized to smooth muscle cells of the developing neointima, and immunocytochemical analysis showed that HMG-I(Y) protein was expressed in the nuclei of these cells. To confirm this association between HMG-I protein induction and cell growth, we assessed HMG-I(Y) and HMGI-C mRNA expression in rat aortic smooth muscle cells (RASMCs) in primary culture. The HMG-I mRNAs were barely detectable in quiescent RASMCs but were induced markedly by serum stimulation. This induction of mRNA by serum was time dependent and peaked at 9 h. Western blot analysis confirmed that HMG-I(Y) protein induction also occurred in vitro. To our knowledge, this is the first demonstration of induction of HMG-I protein expression in proliferating RASMCs in vivo and in vitro. This demonstration suggests that the HMG-I proteins may play an important role in smooth muscle cell proliferation.

Characterization of the mUBC9-binding sites required for E2A protein degradation

Mammalian Ubc9 (mUbc9) is required for rapid degradation of the E2A proteins E12 and E47 by the ubiquitin-proteasome system. We have shown elsewhere that mUbc9 interacts with amino acids 477-530 of E12/E47. Here we test the hypothesis that this region, rich in proline, glutamic acid, serine, and threonine (PEST) residues, serves as the E2A protein degradation domain (DD). An E2A protein lacking this region, E47Delta(478-531), was significantly more stable than wild-type E47(half-life of more than 6 h versus 55 min). Deletion of the E2A DD had no effect on the E-box-binding and transcriptional activity of E47. We mapped two discreet mUbc9-interacting regions within the E2A DD: amino acids 476-494 and 505-513. E2A(505-513) interacted with mUbc9 but not with human Ubc5, MyoD, Id3, or the polymyositis-scleroderma autoantigen. Substitution of the E2A(505-513) central hydrophobic residues with basic residues abolished interaction with mUbc9. Also, full-length E47 lacking the second mUbc9-interacting region was significantly more stable than wild-type E47. Reintroduction of the E2A DD into the long-lived, naturally occurring chimeric oncoprotein E2A-HLF (hepatic leukemic factor) destabilized it, suggesting that this domain can transfer a degradation signal to a heterologous protein. E2A-HLF-DD chimeric protein was stabilized by the proteasome inhibitor LLNL, indicating the role of the ubiquitin-proteasome system mediating degradation through the E2A degradation domain. Our experiments indicate that the E2A DD mediates E2A protein interactions with the ubiquitin-proteasome system and that the E2A DD is required for metabolism of these widely expressed proteins.

Effects of short-term treatment of hyperlipidemia on coronary vasodilator function and myocardial perfusion in regions having substantial impairment of baseline dilator reverse

BACKGROUND

We tested the hypothesis that correction of hyperlipidemia improves coronary vasodilator response and maximal perfusion in myocardial regions having substantial impairment of pretreatment vasodilator capacity.

METHODS AND RESULTS

Measurements of myocardial blood flow were made with PET [13N]ammonia in 12 patients with ischemic heart disease (11 men; age, 65+/-8 years [mean+/-SD]) at rest and during adenosine at 70 and then 140 microg . kg-1 . min-1 for 5 minutes each before and approximately 4 months after simvastatin treatment (40 mg daily). Simvastatin reduced LDL (171+/-13 before versus 99+/-18 mg/dL after simvastatin, P<0.001) and increased HDL (39+/-8 versus 45+/-9 mg/dL, P<0.05). Myocardial segments were classified on the basis of pretreatment blood flow response to 140 microg . kg-1 . min-1 adenosine as normal (flow >/=2 mL . min-1 . g-1) or abnormal (flow <2 mL . min-1 . g-1). In normal segments, baseline myocardial blood flow (0.95+/-0.32) increased (P<0.001) at both low- (1.62+/-0.81) and high- (2.63+/-0.41) dose adenosine and was unchanged both at rest and with adenosine after simvastatin. In abnormal segments, myocardial blood flow at rest (0. 73+/-0.19) increased at low- (1.06+/-0.59, P<0.02) and high- (1. 29+/-0.33, P<0.01) dose adenosine. After simvastatin, myocardial blood flow increased more compared with pretreatment at both low- (1. 37+/-0.66, P<0.05 versus pretreatment) and high- (1.89+/-0.79, P<0. 01 versus pretreatment) dose adenosine.

CONCLUSIONS

Short-term lipid-lowering therapy increases stenotic segment maximal myocardial blood flow by approximately 45%. The mechanism involves enhanced, flow-mediated dilation of stenotic epicardial conduit vessels and may account at least in part for the efficacy of lipid lowering in secondary prevention trials and in reducing ischemic episodes in ambulatory patients.

Induction of heme oxygenase-1 during endotoxemia is downregulated by transforming growth factor-beta1

Heme oxygenase (HO)-1 generates CO, a gas with vasodilatory properties, during heme metabolism. HO-1 is expressed highly in vascular tissue after endotoxin stimulation, and generation of CO through the HO-1 pathway contributes to the hemodynamic compromise of endotoxic shock. Shock related to endotoxemia is an immune-mediated process that involves the generation of proinflammatory cytokines such as interleukin (IL)-1beta. Because transforming growth factor (TGF)-beta1 is a modulator of immune-mediated inflammatory responses and it blocks the hypotension of endotoxic shock, we determined whether TGF-beta1 could be used to reduce expression of HO-1 in vascular tissue and smooth muscle cells. In a rat model of endotoxic shock, lipopolysaccharide-induced HO-1 mRNA and protein expression was reduced by TGF-beta1 in highly vascularized tissue, such as heart and lung, by Northern and Western analysis. Furthermore, TGF-beta1 downregulated HO-1 mRNA after its induction by IL-1beta in vascular smooth muscle cells in culture. TGF-beta1 also decreased HO-1 but not HO-2 protein expression in these cells. TGF-beta1 decreased HO enzyme activity induced in IL-1beta treated vascular smooth muscle cells to a level not different from that in vehicle-treated cells. These studies suggest that this downregulation of HO-1 mRNA and protein expression and decrease in IL-1beta-induced HO enzyme activity may contribute to the beneficial effect of TGF-beta1 on endotoxic shock.

The polymyositis-scleroderma autoantigen interacts with the helix-loop-helix proteins E12 and E47

The basic helix-loop-helix (bHLH) transcription factors E12 and E47 regulate cellular differentiation and proliferation in diverse cell types. While looking for proteins that bind to E12 and E47 by the yeast interaction trap, we isolated the rat (r) homologue of the human (h) polymyositis-scleroderma autoantigen (PM-Scl), which has been localized to the granular layer of the nucleolus and to distinct nucleocytoplasmic foci. The rPM-Scl and hPM-Scl homologues are 96% similar and 91% identical. We found that rPM-Scl mRNA expression was regulated by growth factor stimulation in cultured rat aortic smooth muscle cells. rPM-Scl bound to E12 and E47 but not to Id3, Gax, Myb, OCT-1, or Max. The C terminus of rPM-Scl (amino acids 283-353) interacted specifically with a 54-amino acid domain in E12 that is distinct from the bHLH domain. Finally, cotransfection of rPM-Scl and E47 specifically increased the promoter activity of a luciferase reporter construct containing an E box and did not affect the basal activity of the reporter construct. rPM-Scl appears to be a novel non-HLH-interacting partner of E12/E47 that regulates E2A protein transcription.

Degradation of E2A proteins through a ubiquitin-conjugating enzyme, UbcE2A

The helix-loop-helix E2A proteins (E12 and E47) govern cellular growth and differentiation. To identify binding partners that regulate the function of these ubiquitous transcription factors, we screened for proteins that interacted with the C terminus of E12 by the yeast interaction trap. UbcE2A, a rat enzyme that is highly homologous to and functionally complements the yeast ubiquitin-conjugating enzyme UBC9, was identified and cloned. UbcE2A appears to be an E2A-selective ubiquitin-conjugating enzyme because it interacts specifically with a 54-amino acid region in E47-(477-530) distinct from the helix-loop-helix domain. In contrast, most of the UbcE2A protein is required for interaction with an E2A protein. The E2A proteins appear to be degraded by the ubiquitin-proteasome pathway because the E12 half-life of 60 min is extended by the proteasome inhibitor MG132, and E12 is multi-ubiquitinated in vivo. Finally, antisense UbcE2A reduces E12 degradation. By participating in the degradation of the E2A proteins, UbcE2A may regulate cell growth and differentiation.